Highly stable gel electrolytes for dye solar cells based on chemically engineered polymethacrylic hosts.

PubMed

De Gregorio, Gian Luca; Agosta, Rita; Giannuzzi, Roberto; Martina, Francesca; De Marco, Luisa; Manca, Michele; Gigli, Giuseppe

2012-03-25

Four different species of ionically conductive polymers were synthesized and successfully implemented to formulate novel quasi-solid electrolytes for dye solar cells. A power conversion efficiency superior to 85% of the correspondent liquid electrolyte as well as an excellent cell's stability was demonstrated after 500 days of storage.

Process for Preparing Microcapsules Having Gelatin Walls Crosslinked with Quinone.

DTIC Science & Technology

A process for conveniently producing microcapsules containing a gelatin wall crosslinked with quinone and a core of an active compound such as a...provides microcapsules of excellent strength, storage stability, and resistance to aqueous exposure, such that the rate of release of the fouling reducing agent can be controlled with precision. jg

Facile synthesis of nickel-doped Co9S8 hollow nanoparticles with large surface-controlled pseudocapacitive and fast sodium storage

NASA Astrophysics Data System (ADS)

Zhou, Hepeng; Cao, Yijun; Ma, Zilong; Li, Shulei

2018-05-01

Transition metal sulfides are considered to be promising candidates as anodes for sodium ion batteries (SIBs). However, their further applications are limited by poor electrical conductivity and sluggish electrochemical kinetics. We report, for the first time, nickel-doped Co9S8 hollow nanoparticles as SIB anodes with enhanced electrical conductivity and a large pseudocapacitive effect, leading to fast kinetics. This compound exhibits excellent sodium storage performance, including a high capacity of 556.7 mA h g-1, a high rate capability of 2000 mA g-1 and an excellent stability up to 200 cycles. The results demonstrate that nickel-doped Co9S8 hollow nanoparticles are a promising anode material for SIBs.

Facile synthesis of nickel-doped Co9S8 hollow nanoparticles with large surface-controlled pseudocapacitive and fast sodium storage.

PubMed

Zhou, Hepeng; Cao, Yijun; Ma, Zilong; Li, Shulei

2018-05-11

Transition metal sulfides are considered to be promising candidates as anodes for sodium ion batteries (SIBs). However, their further applications are limited by poor electrical conductivity and sluggish electrochemical kinetics. We report, for the first time, nickel-doped Co 9 S 8 hollow nanoparticles as SIB anodes with enhanced electrical conductivity and a large pseudocapacitive effect, leading to fast kinetics. This compound exhibits excellent sodium storage performance, including a high capacity of 556.7 mA h g -1 , a high rate capability of 2000 mA g -1 and an excellent stability up to 200 cycles. The results demonstrate that nickel-doped Co 9 S 8 hollow nanoparticles are a promising anode material for SIBs.

Na3.4Zr1.8Mg0.2Si2PO12 filled poly(ethylene oxide)/Na(CF3SO2)2N as flexible composite polymer electrolyte for solid-state sodium batteries

NASA Astrophysics Data System (ADS)

Zhang, Zhizhen; Xu, Kaiqi; Rong, Xiaohui; Hu, Yong-Sheng; Li, Hong; Huang, Xuejie; Chen, Liquan

2017-12-01

Solid electrolytes with high ionic conductivity and excellent electrochemical stability are of prime significance to enable the application of solid-state batteries in energy storage and conversion. In this study, solid composite polymer electrolytes (CPEs) based on sodium bis(trifluorosulfonyl) imide (NaTFSI) and poly (ethylene oxide) (PEO) incorporated with active ceramic filler (NASICON) are reported for the first time. With the addition of NASICON fillers, the thermal stability and electrochemical stability of the CPEs are improved. A high conductivity of 2.8 mS/cm (at 80 °C) is readily achieved when the content of the NASICON filler in the composite polymer reaches 50 wt%. Furthermore, Na3V2(PO4)3/CPE/Na solid-state batteries using this composite electrolyte display good rate and excellent cycle performance.

Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) for application of ascorbyl palmitate.

PubMed

Uner, M; Wissing, S A; Yener, G; Müller, R H

2005-08-01

The aim of this study was to improve the chemical stability of ascorbyl palmitate (AP) in a colloidal lipid carrier for its topical use. For this purpose, AP-loaded solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC) and for comparison, a nanoemulsion (NE) were prepared employing the high pressure homogenization technique and stored at room temperature (RT), 4 degrees C and 40 degrees C. During 3 months, physical stability of these formulations compared to placebo formulations which were prepared by the same production method, was studied including recrystallization behaviour of the lipid with differential scanning calorimetry (DSC), particle size distribution and storage stability with photon correlation spectroscopy (PCS) and laser diffractometry (LD). After evaluating data indicating excellent physical stability, AP-loaded SLN, NLC and NE were incorporated into a hydrogel by the same production method as the next step. Degradation of AP by HPLC and physical stability in the same manner were investigated at the same storage temperatures during 3 months. As a result, AP was found most stable in both the NLC and SLN stored at 4 degrees C (p > 0.05) indicating the importance of storage temperature. Nondegraded AP content in NLC, SLN and NE was found to be 71.1% +/- 1.4, 67.6% +/- 2.9 and 55.2% +/- 0.3 after 3 months, respectively. Highest degradation was observed with NE at all the storage temperatures indicating even importance of the carrier structure.

Recent Advances in Porous Carbon Materials for Electrochemical Energy Storage.

PubMed

Wang, Libin; Hu, Xianluo

2018-06-18

Climate change and the energy crisis have promoted the rapid development of electrochemical energy-storage devices. Owing to many intriguing physicochemical properties, such as excellent chemical stability, high electronic conductivity, and a large specific surface area, porous carbon materials have always been considering as a promising candidate for electrochemical energy storage. To date, a wide variety of porous carbon materials based upon molecular design, pore control, and compositional tailoring have been proposed for energy-storage applications. This focus review summarizes recent advances in the synthesis of various porous carbon materials from the view of energy storage, particularly in the past three years. Their applications in representative electrochemical energy-storage devices, such as lithium-ion batteries, supercapacitors, and lithium-ion hybrid capacitors, are discussed in this review, with a look forward to offer some inspiration and guidelines for the exploitation of advanced carbon-based energy-storage materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon Redox-Polymer-Gel Hybrid Supercapacitors.

PubMed

Vlad, A; Singh, N; Melinte, S; Gohy, J-F; Ajayan, P M

2016-02-26

Energy storage devices that provide high specific power without compromising on specific energy are highly desirable for many electric-powered applications. Here, we demonstrate that polymer organic radical gel materials support fast bulk-redox charge storage, commensurate to surface double layer ion exchange at carbon electrodes. When integrated with a carbon-based electrical double layer capacitor, nearly ideal electrode properties such as high electrical and ionic conductivity, fast bulk redox and surface charge storage as well as excellent cycling stability are attained. Such hybrid carbon redox-polymer-gel electrodes support unprecedented discharge rate of 1,000C with 50% of the nominal capacity delivered in less than 2 seconds. Devices made with such electrodes hold the potential for battery-scale energy storage while attaining supercapacitor-like power performances.

Extrusion cast explosive

DOEpatents

Scribner, Kenneth J.

1985-01-01

Improved, multiphase, high performance, high energy, extrusion cast explosive compositions, comprising, a crystalline explosive material; an energetic liquid plasticizer; a urethane prepolymer, comprising a blend of polyvinyl formal, and polycaprolactone; a polyfunctional isocyanate; and a catalyst are disclosed. These new explosive compositions exhibit higher explosive content, a smooth detonation front, excellent stability over long periods of storage, and lower sensitivity to mechanical stimulants.

In Situ Encapsulating α-MnS into N,S-Codoped Nanotube-Like Carbon as Advanced Anode Material: α → β Phase Transition Promoted Cycling Stability and Superior Li/Na-Storage Performance in Half/Full Cells.

PubMed

Liu, Dai-Huo; Li, Wen-Hao; Zheng, Yan-Ping; Cui, Zheng; Yan, Xin; Liu, Dao-Sheng; Wang, Jiawei; Zhang, Yu; Lü, Hong-Yan; Bai, Feng-Yang; Guo, Jin-Zhi; Wu, Xing-Long

2018-04-02

Incorporation of N,S-codoped nanotube-like carbon (N,S-NTC) can endow electrode materials with superior electrochemical properties owing to the unique nanoarchitecture and improved kinetics. Herein, α-MnS nanoparticles (NPs) are in situ encapsulated into N,S-NTC, preparing an advanced anode material (α-MnS@N,S-NTC) for lithium-ion/sodium-ion batteries (LIBs/SIBs). It is for the first time revealed that electrochemical α → β phase transition of MnS NPs during the 1st cycle effectively promotes Li-storage properties, which is deduced by the studies of ex situ X-ray diffraction/high-resolution transmission electron microscopy and electrode kinetics. As a result, the optimized α-MnS@N,S-NTC electrode delivers a high Li-storage capacity (1415 mA h g -1 at 50 mA g -1 ), excellent rate capability (430 mA h g -1 at 10 A g -1 ), and long-term cycling stability (no obvious capacity decay over 5000 cycles at 1 A g -1 ) with retained morphology. In addition, the N,S-NTC-based encapsulation plays the key roles on enhancing the electrochemical properties due to its high conductivity and unique 1D nanoarchitecture with excellent protective effects to active MnS NPs. Furthermore, α-MnS@N,S-NTC also delivers high Na-storage capacity (536 mA h g -1 at 50 mA g -1 ) without the occurrence of such α → β phase transition and excellent full-cell performances as coupling with commercial LiFePO 4 and LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathodes in LIBs as well as Na 3 V 2 (PO 4 ) 2 O 2 F cathode in SIBs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cervarix, the GSK HPV-16/HPV-18 AS04-adjuvanted cervical cancer vaccine, demonstrates stability upon long-term storage and under simulated cold chain break conditions.

PubMed

Le Tallec, David; Doucet, Diane; Elouahabi, Abdelatif; Harvengt, Pol; Deschuyteneer, Michel; Deschamps, Marguerite

2009-07-01

Cervarix is a recombinant human papillomavirus (HPV)-16 and -18 L1 virus-like-particle (VLP) AS04-adjuvanted vaccine designed to protect against cervical intraepithelial neoplasia and cervical cancer caused by the HPV types 16 and 18. Assessment of the stability of the vaccine during long-term storage and after transient exposure to temperatures out of normal storage range is an integrated part of vaccine quality evaluation. This assessment was done with vaccine samples stored at 2-8 degrees C for up to 36 months, with or without simulated cold chain break (either one week at 37 degrees C, or two or four weeks at 25 degrees C). Among the stability-indicating parameters, antigenicity and immunogenicity were evaluated along with L1 antigen integrity and adsorption to aluminum. Differential scanning calorimetry (DSC) was used to investigate the structural stability of the VLPs before and after vaccine formulation and over time. Cervarix was stable at 2-8 degrees C for at least three years, and the occurrence of cold chain break had no impact, as shown by unchanged product characteristics during the full storage period. DSC analysis demonstrated that the structure of the HPV-16 and -18 L1 proteins and their corresponding VLPs was not affected throughout the manufacturing process. Moreover, the structure of aluminum-adsorbed HPV-16 and -18 L1 VLPs was robust over a 14-month test period. In conclusion, Cervarix was very stable upon long-term storage at 2-8 degrees C with or without transient exposure to higher temperatures (up to 37 degrees C). The observed robust structure of the L1 VLPs contributes to the excellent stability of Cervarix.

Rapid fabrication of superhydrophobic Al/Fe2O3 nanothermite film with excellent energy-release characteristics and long-term storage stability

NASA Astrophysics Data System (ADS)

Ke, Xiang; Zhou, Xiang; Hao, Gaozi; Xiao, Lei; Liu, Jie; Jiang, Wei

2017-06-01

One of the challenges for the application of energetic materials is their energy-retaining capabilities after long-term storage. In this study, we report a facile method to fabricate superhydrophobic Al/Fe2O3 nanothermite film by combining electrophoretic deposition and surface modification technologies. Different concentrations of dispersion solvents and additives are investigated to optimize the deposition parameters. Meanwhile, the dependence of deposition rates on nanoparticle concentrations is also studied. The surface morphology and chemical composition are characterized by field-emission scanning electron microscopy, X-ray diffraction, X-ray energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. A static contact angles as high as 156° shows the superhydrophobicity of the nanothermite film. Natural and accelerated aging tests are performed and the thermal behavior is analyzed. Thermal analysis shows that the surface modification contributes to significantly improved energy-release characteristics for both fresh and aged samples, which is supposed to be attributed to the preignition reaction between Al2O3 shell and FAS-17. Superhydrophobic Al/Fe2O3 nanothermite film exhibits excellent long-time storage stability with 83.4% of energy left in natural aging test and 60.5% in accelerated aging test. This study is instructive to the practical applications of nanothermites, especially in highly humid environment.

A Porphyrin Complex as a Self-Conditioned Electrode Material for High-Performance Energy Storage.

PubMed

Gao, Ping; Chen, Zhi; Zhao-Karger, Zhirong; Mueller, Jonathan E; Jung, Christoph; Klyatskaya, Svetlana; Diemant, Thomas; Fuhr, Olaf; Jacob, Timo; Behm, R Jürgen; Ruben, Mario; Fichtner, Maximilian

2017-08-21

The novel functionalized porphyrin [5,15-bis(ethynyl)-10,20-diphenylporphinato]copper(II) (CuDEPP) was used as electrodes for rechargeable energy-storage systems with an extraordinary combination of storage capacity, rate capability, and cycling stability. The ability of CuDEPP to serve as an electron donor or acceptor supports various energy-storage applications. Combined with a lithium negative electrode, the CuDEPP electrode exhibited a long cycle life of several thousand cycles and fast charge-discharge rates up to 53 C and a specific energy density of 345 Wh kg -1 at a specific power density of 29 kW kg -1 . Coupled with a graphite cathode, the CuDEPP anode delivered a specific power density of 14 kW kg -1 . Whereas the capacity is in the range of that of ordinary lithium-ion batteries, the CuDEPP electrode has a power density in the range of that of supercapacitors, thus opening a pathway toward new organic electrodes with excellent rate capability and cyclic stability. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon Redox-Polymer-Gel Hybrid Supercapacitors

PubMed Central

Vlad, A.; Singh, N.; Melinte, S.; Gohy, J.-F.; Ajayan, P.M.

2016-01-01

Energy storage devices that provide high specific power without compromising on specific energy are highly desirable for many electric-powered applications. Here, we demonstrate that polymer organic radical gel materials support fast bulk-redox charge storage, commensurate to surface double layer ion exchange at carbon electrodes. When integrated with a carbon-based electrical double layer capacitor, nearly ideal electrode properties such as high electrical and ionic conductivity, fast bulk redox and surface charge storage as well as excellent cycling stability are attained. Such hybrid carbon redox-polymer-gel electrodes support unprecedented discharge rate of 1,000C with 50% of the nominal capacity delivered in less than 2 seconds. Devices made with such electrodes hold the potential for battery-scale energy storage while attaining supercapacitor-like power performances. PMID:26917470

Extrusion cast explosive

DOEpatents

Scribner, K.J.

1985-01-29

Improved, multiphase, high performance, high energy, extrusion cast explosive compositions, comprising, a crystalline explosive material; an energetic liquid plasticizer; a urethane prepolymer, comprising a blend of polyvinyl formal, and polycaprolactone; a polyfunctional isocyanate; and a catalyst are disclosed. These new explosive compositions exhibit higher explosive content, a smooth detonation front, excellent stability over long periods of storage, and lower sensitivity to mechanical stimulants. 1 fig.

Extrusion cast explosive

DOEpatents

Scribner, K.J.

1985-11-26

Disclosed is an improved, multiphase, high performance, high energy, extrusion cast explosive compositions, comprising, a crystalline explosive material; an energetic liquid plasticizer; a urethane prepolymer, comprising a blend of polyvinyl formal, and polycaprolactone; a polyfunctional isocyanate; and a catalyst. These new explosive compositions exhibit higher explosive content, a smooth detonation front, excellent stability over long periods of storage, and lower sensitivity to mechanical stimulants. 1 fig.

Enhanced electrochemical performance and storage property of LiNi0.815Co0.15Al0.035O2 via Al gradient doping

NASA Astrophysics Data System (ADS)

Duan, Jianguo; Hu, Guorong; Cao, Yanbing; Tan, Chaopu; Wu, Ceng; Du, Ke; Peng, Zhongdong

2016-09-01

LiNi1-x-yCoxAlyO2 is a commonly used Ni-rich cathode material because of its relatively low cost, excellent rate capability and high gravimetric energy density. Surface modification is an efficient way to overcome the shortcomings of Ni-rich cathodes such as poor cycling stability and poor thermal stability. A high-powered concentration-gradient cathode material with an average composition of LiNi0.815Co0.15Al0.035O2 (LGNCAO) has been successfully synthesized by using spherical concentration-gradient Ni0.815Co0.15Al0.035(OH)2 (GNCA)as the starting material. An efficient design of the Al3+ precipitation method is developed, which enables obtaining spherical GNCA with ∼10 μm particle size and high tap density. In LGNCAO, the nickel and cobalt concentration decreases gradually whereas the aluminum concentration increases from the centre to the outer layer of each particle. Electrochemical performance and storage properties of LGNCAO have been investigated comparatively. The LGNCAO displays better electrochemical performance and improved storage stability than LNCAO.

Structural water engaged disordered vanadium oxide nanosheets for high capacity aqueous potassium-ion storage.

PubMed

Charles, Daniel Scott; Feygenson, Mikhail; Page, Katharine; Neuefeind, Joerg; Xu, Wenqian; Teng, Xiaowei

2017-05-23

Aqueous electrochemical energy storage devices using potassium-ions as charge carriers are attractive due to their superior safety, lower cost and excellent transport properties compared to other alkali ions. However, the accommodation of potassium-ions with satisfactory capacity and cyclability is difficult because the large ionic radius of potassium-ions causes structural distortion and instabilities even in layered electrodes. Here we report that water induces structural rearrangements of the vanadium-oxygen octahedra and enhances stability of the highly disordered potassium-intercalated vanadium oxide nanosheets. The vanadium oxide nanosheets engaged by structural water achieves high capacity (183 mAh g -1 in half-cells at a scan rate of 5 mV s -1 , corresponding to 0.89 charge per vanadium) and excellent cyclability (62.5 mAh g -1 in full cells after 5,000 cycles at 10 C). The promotional effects of structural water on the disordered vanadium oxide nanosheets will contribute to the exploration of disordered structures from earth-abundant elements for electrochemical energy storage.

Structural water engaged disordered vanadium oxide nanosheets for high capacity aqueous potassium-ion storage

DOE PAGES

Charles, Daniel Scott; Feygenson, Mikhail; Page, Katharine; ...

2017-05-23

Aqueous electrochemical energy storage devices using potassium-ions as charge carriers are attractive due to their superior safety, lower cost and excellent transport properties compared to other alkali ions. However, the accommodation of potassium-ions with satisfactory capacity and cyclability is difficult because large ionic radius of potassium-ions causes structural distortion and instabilities even in layered electrodes. Here we report that water induces structural rearrangements of the vanadium-oxygen octahedra and enhances stability of the highly disordered potassium-intercalated vanadium oxide nanosheets. The vanadium oxide nanosheets engaged by structural water achieves high capacity (183 mAh g -1 in half-cells at a scan rate ofmore » 5 mV s -1, corresponding to 0.89 charge per vanadium) and excellent cyclability (62.5 mAh g -1 in full-cells after 5,000 cycles at 10 C). Finally, the promotional effects of structural water on the disordered vanadium oxide nanosheets will contribute to the exploration of disordered structures from earth-abundant elements for electrochemical energy storage.« less

Structural water engaged disordered vanadium oxide nanosheets for high capacity aqueous potassium-ion storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charles, Daniel Scott; Feygenson, Mikhail; Page, Katharine

Aqueous electrochemical energy storage devices using potassium-ions as charge carriers are attractive due to their superior safety, lower cost and excellent transport properties compared to other alkali ions. However, the accommodation of potassium-ions with satisfactory capacity and cyclability is difficult because large ionic radius of potassium-ions causes structural distortion and instabilities even in layered electrodes. Here we report that water induces structural rearrangements of the vanadium-oxygen octahedra and enhances stability of the highly disordered potassium-intercalated vanadium oxide nanosheets. The vanadium oxide nanosheets engaged by structural water achieves high capacity (183 mAh g -1 in half-cells at a scan rate ofmore » 5 mV s -1, corresponding to 0.89 charge per vanadium) and excellent cyclability (62.5 mAh g -1 in full-cells after 5,000 cycles at 10 C). Finally, the promotional effects of structural water on the disordered vanadium oxide nanosheets will contribute to the exploration of disordered structures from earth-abundant elements for electrochemical energy storage.« less

Stability of tacrolimus injection diluted in 0.9% sodium chloride injection and stored in Excel bags.

PubMed

Myers, Alan L; Zhang, Yanping; Kawedia, Jitesh D; Shank, Brandon R; Deaver, Melissa A; Kramer, Mark A

2016-12-15

The chemical stability and physical compatibility of tacrolimus i.v. infusion solutions prepared in Excel bags and stored at 23 or 4 °C for up to nine days were studied. Tacrolimus admixtures (2, 4, and 8 μg/mL) were prepared in Excel bags using 0.9% sodium chloride injection and stored at 23 °C without protection from light or at 4 °C in the dark. Test samples were withdrawn from triplicate bag solutions immediately after preparation and at predetermined time intervals (1, 3, 5, 7, and 9 days). Chemical stability was assessed by measuring tacrolimus concentrations using a validated stability-indicating high-performance liquid chromatography assay. The physical stability of the admixtures was assessed by visual examination and by measuring turbidity, particle size, and drug content. All test solutions stored at 23 or 4 °C had a no greater than 6% loss of the initial tacrolimus concentration throughout the nine-day study period. All test samples of tacrolimus admixtures, under both storage conditions, were without precipitation and remained clear initially and throughout the nine-day observation period. Changes in turbidities were minor; measured particulates remained few in number in all samples throughout the study. Extemporaneously prepared infusion solutions of tacrolimus 2, 4, and 8 μg/mL in 0.9% sodium chloride injection in Excel bags were chemically and physically stable for at least nine days when stored at room temperature (23 °C) without protection from light and when stored in a refrigerator (4 °C) in the dark. Copyright © 2016 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

Coordination complex pyrolyzation for the synthesis of nanostructured GeO₂ with high lithium storage properties.

PubMed

Li, Xiaona; Liang, Jianwen; Hou, Zhiguo; Zhu, Yongchun; Wang, Yan; Qian, Yitai

2014-11-21

A new (NH4)3H(Ge7O16)(H2O)2.72 precursor-pyrolyzation approach was designed and developed for the facile synthesis of nanostructured GeO2, avoiding the use of any hazardous or expensive germanium compounds. The products show promising anode application in lithium ion batteries with high capacity and excellent cycling stability.

Soft-Template Construction of 3D Macroporous Polypyrrole Scaffolds.

PubMed

Liu, Shaohua; Wang, Faxing; Dong, Renhao; Zhang, Tao; Zhang, Jian; Zheng, Zhikun; Mai, Yiyong; Feng, Xinliang

2017-04-01

A bottom-up approach toward 3D hierarchical macroporous polypyrrole aerogels is demonstrated via soft template-directed synthesis and self-assembly of ultrathin polypyrrole nanosheets in solution, which present interconnected macropores, ultrathin walls, and large specific surface areas, thereby exhibiting a high capacity, satisfactory rate capability, and excellent cycling stability for Na-ion storage. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cobalt Disulfide Nanoparticles Embedded in Porous Carbonaceous Micro-Polyhedrons Interlinked by Carbon Nanotubes for Superior Lithium and Sodium Storage.

PubMed

Ma, Yuan; Ma, Yanjiao; Bresser, Dominic; Ji, Yuanchun; Geiger, Dorin; Kaiser, Ute; Streb, Carsten; Varzi, Alberto; Passerini, Stefano

2018-06-27

Transition metal sulfides are appealing electrode materials for lithium and sodium batteries owing to their high theoretical capacity. However, they are commonly characterized by rather poor cycling stability and low rate capability. Herein, we investigate CoS 2 , serving as a model compound. We synthesized a porous CoS 2 /C micro-polyhedron composite entangled in a carbon-nanotube-based network (CoS 2 -C/CNT), starting from zeolitic imidazolate frameworks-67 as a single precursor. Following an efficient two-step synthesis strategy, the obtained CoS 2 nanoparticles are uniformly embedded in porous carbonaceous micro-polyhedrons, interwoven with CNTs to ensure high electronic conductivity. The CoS 2 -C/CNT nanocomposite provides excellent bifunctional energy storage performance, delivering 1030 mAh g -1 after 120 cycles and 403 mAh g -1 after 200 cycles (at 100 mA g -1 ) as electrode for lithium-ion (LIBs) and sodium-ion batteries (SIBs), respectively. In addition to these high capacities, the electrodes show outstanding rate capability and excellent long-term cycling stability with a capacity retention of 80% after 500 cycles for LIBs and 90% after 200 cycles for SIBs. In situ X-ray diffraction reveals a significant contribution of the partially graphitized carbon to the lithium and at least in part also for the sodium storage and the report of a two-step conversion reaction mechanism of CoS 2 , eventually forming metallic Co and Li 2 S/Na 2 S. Particularly the lithium storage capability at elevated (dis-)charge rates, however, appears to be substantially pseudocapacitive, thus benefiting from the highly porous nature of the nanocomposite.

Layer-by-layer grown scalable redox-active ruthenium-based molecular multilayer thin films for electrochemical applications and beyond.

PubMed

Kaliginedi, Veerabhadrarao; Ozawa, Hiroaki; Kuzume, Akiyoshi; Maharajan, Sivarajakumar; Pobelov, Ilya V; Kwon, Nam Hee; Mohos, Miklos; Broekmann, Peter; Fromm, Katharina M; Haga, Masa-aki; Wandlowski, Thomas

2015-11-14

Here we report the first study on the electrochemical energy storage application of a surface-immobilized ruthenium complex multilayer thin film with anion storage capability. We employed a novel dinuclear ruthenium complex with tetrapodal anchoring groups to build well-ordered redox-active multilayer coatings on an indium tin oxide (ITO) surface using a layer-by-layer self-assembly process. Cyclic voltammetry (CV), UV-Visible (UV-Vis) and Raman spectroscopy showed a linear increase of peak current, absorbance and Raman intensities, respectively with the number of layers. These results indicate the formation of well-ordered multilayers of the ruthenium complex on ITO, which is further supported by the X-ray photoelectron spectroscopy analysis. The thickness of the layers can be controlled with nanometer precision. In particular, the thickest layer studied (65 molecular layers and approx. 120 nm thick) demonstrated fast electrochemical oxidation/reduction, indicating a very low attenuation of the charge transfer within the multilayer. In situ-UV-Vis and resonance Raman spectroscopy results demonstrated the reversible electrochromic/redox behavior of the ruthenium complex multilayered films on ITO with respect to the electrode potential, which is an ideal prerequisite for e.g. smart electrochemical energy storage applications. Galvanostatic charge-discharge experiments demonstrated a pseudocapacitor behavior of the multilayer film with a good specific capacitance of 92.2 F g(-1) at a current density of 10 μA cm(-2) and an excellent cycling stability. As demonstrated in our prototypical experiments, the fine control of physicochemical properties at nanometer scale, relatively good stability of layers under ambient conditions makes the multilayer coatings of this type an excellent material for e.g. electrochemical energy storage, as interlayers in inverted bulk heterojunction solar cell applications and as functional components in molecular electronics applications.

Interfacial film stabilized W/O/W nano multiple emulsions loaded with green tea and lotus extracts: systematic characterization of physicochemical properties and shelf-storage stability.

PubMed

Mahmood, Tariq; Akhtar, Naveed; Manickam, Sivakumar

2014-05-12

Multiple emulsions have excellent encapsulating potential and this investigation has been aimed to encapsulate two different plant extracts as functional cosmetic agents in the W/O/W multiple emulsions and the resultant system's long term stability has been determined in the presence of a thickener, hydroxypropyl methylcellulose (HPMC). Multiple W/O/W emulsions have been generated using cetyl dimethicone copolyol as lipophilic emulsifier and a blend of polyoxyethylene (20) cetyl ether and cetomacrogol 1000® as hydrophilic emulsifiers. The generated multiple emulsions have been characterized with conductivity, pH, microscopic analysis, phase separation and rheology for a period of 30 days. Moreover, long term shelf-storage stability has been tested to understand the shelf-life by keeping the generated multiple emulsion formulations at 25 ± 10°C and at 40 ± 10% relative humidity for a period of 12 months. It has been observed that the hydrophilic emulsifiers and HPMC have considerably improved the stability of multiple emulsions for the followed period of 12 months at different storage conditions. These multiple emulsions have shown improved entrapment efficiencies concluded on the release rate of conductometric tracer entrapped in the inner aqueous phase of the multiple emulsions. Multiple emulsions have been found to be stable for a longer period of time with promising characteristics. Hence, stable multiple emulsions loaded with green tea and lotus extracts could be explored for their cosmetic benefits.

The orientation construction of S and N dual-doped discoid-like graphene with high-rate electrode property

NASA Astrophysics Data System (ADS)

Song, Xinyu; Ma, Xinlong; Ning, Guoqing; Gao, Daowei; Yu, Zhiqing; Xiao, Zhihua

2018-06-01

The orientation construction of S and N dual-doped discoid-like graphene (labeled as SNDG) is achieved by regular arrangement of the polycyclic aromatics in pitch molecules using natural diatomites as templates. The superior electrochemical energy storage ability of SNDG is demonstrated by cathode and anode tests, respectively. The synergistic effects of the robust scaffold coupled with the hollow structure, unique porous structure, the excellent structural stability and the dual-doping of S and N lead to the electrode property enhancement in terms of rate capability and durability. The Li ion hybrid capacitor using SNDG as both anode and cathode, presents excellent long-term cycling stability and markedly energy and power densities (up to 143 Wh kg-1 and 13,548 W kg-1). This work provides a novel pathway to realize the mass production of high-rate electrode materials via the high value-added utilization of pitch.

Amorphous Red Phosphorus Embedded in Sandwiched Porous Carbon Enabling Superior Sodium Storage Performances.

PubMed

Wu, Ying; Liu, Zheng; Zhong, Xiongwu; Cheng, Xiaolong; Fan, Zhuangjun; Yu, Yan

2018-03-01

The red P anode for sodium ion batteries has attracted great attention recently due to the high theoretical capacity, but the poor intrinsic electronic conductivity and large volume expansion restrain its widespread applications. Herein, the red P is successfully encapsulated into the cube shaped sandwich-like interconnected porous carbon building (denoted as P@C-GO/MOF-5) via the vaporization-condensation method. Superior cycling stability (high capacity retention of about 93% at 2 A g -1 after 100 cycles) and excellent rate performance (502 mAh g -1 at 10 A g -1 ) can be obtained for the P@C-GO/MOF-5 electrode. The superior electrochemical performance can be ascribed to the successful incorporation of red P into the unique carbon matrix with large surface area and pore volume, interconnected porous structure, excellent electronic conductivity and superior structural stability. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Phase-Separation Route to Synthesize Porous CNTs with Excellent Stability for Na+ Storage.

PubMed

Chen, Zhi; Wang, Taihong; Zhang, Ming; Cao, Guozhong

2017-06-01

Porous carbon nanotubes (CNTs) are obtained by removing MoO 2 nanoparticles from MoO 2 @C core@shell nanofibers which are synthesized by phase-segregation via a single-needle electrospinning method. The specific surface area of porous CNTs is 502.9 m 2 g -1 , and many oxygen-containing functional groups (COH, CO) are present. As anodes for sodium-ion batteries, the porous CNT electrode displays excellent rate performance and cycling stability (110 mA h g -1 after 1200 cycles at 5 A g -1 ). Those high properties can be attributed to the porous structure and surface modification to steadily store Na + with high capacity. The work provides a facile and broadly applicable way to fabricate the porous CNTs and their composites for batteries, catalysts, and fuel cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Excess Li-Ion Storage on Reconstructed Surfaces of Nanocrystals To Boost Battery Performance

DOE PAGES

Duan, Yandong; Zhang, Bingkai; Zheng, Jiaxin; ...

2017-08-03

Because of their enhanced kinetic properties, nanocrystallites have received much attention as potential electrode materials for energy storage. However, because of the large specific surface areas of nanocrystallites, they usually suffer from decreased energy density, cycling stability, and effective electrode capacity. Here, in this work, we report a size-dependent excess capacity beyond theoretical value (170 mA h g -1) by introducing extra lithium storage at the reconstructed surface in nanosized LiFePO 4 (LFP) cathode materials (186 and 207 mA h g -1 in samples with mean particle sizes of 83 and 42 nm, respectively). Moreover, this LFP composite also showsmore » excellent cycling stability and high rate performance. Our multimodal experimental characterizations and ab initio calculations reveal that the surface extra lithium storage is mainly attributed to the charge passivation of Fe by the surface C–O–Fe bonds, which can enhance binding energy for surface lithium by compensating surface Fe truncated symmetry to create two types of extra positions for Li-ion storage at the reconstructed surfaces. Such surface reconstruction nanotechnology for excess Li-ion storage makes full use of the large specific surface area of the nanocrystallites, which can maintain the fast Li-ion transport and greatly enhance the capacity. Finally, this discovery and nanotechnology can be used for the design of high-capacity and efficient lithium ion batteries.« less

Excess Li-Ion Storage on Reconstructed Surfaces of Nanocrystals To Boost Battery Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, Yandong; Zhang, Bingkai; Zheng, Jiaxin

Because of their enhanced kinetic properties, nanocrystallites have received much attention as potential electrode materials for energy storage. However, because of the large specific surface areas of nanocrystallites, they usually suffer from decreased energy density, cycling stability, and effective electrode capacity. Here, in this work, we report a size-dependent excess capacity beyond theoretical value (170 mA h g -1) by introducing extra lithium storage at the reconstructed surface in nanosized LiFePO 4 (LFP) cathode materials (186 and 207 mA h g -1 in samples with mean particle sizes of 83 and 42 nm, respectively). Moreover, this LFP composite also showsmore » excellent cycling stability and high rate performance. Our multimodal experimental characterizations and ab initio calculations reveal that the surface extra lithium storage is mainly attributed to the charge passivation of Fe by the surface C–O–Fe bonds, which can enhance binding energy for surface lithium by compensating surface Fe truncated symmetry to create two types of extra positions for Li-ion storage at the reconstructed surfaces. Such surface reconstruction nanotechnology for excess Li-ion storage makes full use of the large specific surface area of the nanocrystallites, which can maintain the fast Li-ion transport and greatly enhance the capacity. Finally, this discovery and nanotechnology can be used for the design of high-capacity and efficient lithium ion batteries.« less

Development of High Heat Input Welding High Strength Steel Plate for Oil Storage Tank in Xinyu Steel Company

NASA Astrophysics Data System (ADS)

Zhao, Hemin; Dong, Fujun; Liu, Xiaolin; Xiong, Xiong

This essay introduces the developed high-heat input welding quenched and tempered pressure vessel steel 12MnNiVR for oil storage tank by Xinyu Steel, which passed the review by the Boiler and Pressure Vessel Standards Technical Committee in 2009. The review comments that compared to the domestic and foreign similar steel standard, the key technical index of enterprise standard were in advanced level. After the heat input of 100kJ/cm electro-gas welding, welded points were still with excellent low temperature toughness at -20°C. The steel plate may be constructed for oil storage tank, which has been permitted by thickness range from 10 to 40mm, and design temperature among -20°C-100°C. It studied microstructure genetic effects mechanical properties of the steel. Many production practices indicated that the mechanical properties of products and the steel by stress relief heat treatment of steel were excellent, with pretreatment of hot metal, converter refining, external refining, protective casting, TMCP and heat treatment process measurements. The stability of performance and matured technology of Xinyu Steel support the products could completely service the demand of steel constructed for 10-15 million cubic meters large oil storage tank.

New energy storage option: toward ZnCo2O4 nanorods/nickel foam architectures for high-performance supercapacitors.

PubMed

Liu, Bin; Liu, Boyang; Wang, Qiufan; Wang, Xianfu; Xiang, Qingyi; Chen, Di; Shen, Guozhen

2013-10-23

Hierarchical ZnCo2O4/nickel foam architectures were first fabricated from a simple scalable solution approach, exhibiting outstanding electrochemical performance in supercapacitors with high specific capacitance (∼1400 F g(-1) at 1 A g(-1)), excellent rate capability (72.5% capacity retention at 20 A g(-1)), and good cycling stability (only 3% loss after 1000 cycles at 6 A g(-1)). All-solid-state supercapacitors were also fabricated by assembling two pieces of the ZnCo2O4-based electrodes, showing superior performance in terms of high specific capacitance and long cycling stability. Our work confirms that the as-prepared architectures can not only be applied in high energy density fields, but also be used in high power density applications, such as electric vehicles, flexible electronics, and energy storage devices.

High-performance supercapacitors of Cu-based porous coordination polymer nanowires and the derived porous CuO nanotubes.

PubMed

Wu, Meng-Ke; Zhou, Jiao-Jiao; Yi, Fei-Yan; Chen, Chen; Li, Yan-Li; Li, Qin; Tao, Kai; Han, Lei

2017-12-12

Electrode materials for supercapacitors with one-dimensional porous nanostructures, such as nanowires and nanotubes, are very attractive for high-efficiency storage of electrochemical energy. Herein, ultralong Cu-based porous coordination polymer nanowires (copper-l-aspartic acid) were used as the electrode material for supercapacitors, for the first time. The as-prepared material exhibits a high specific capacitance of 367 F g -1 at 0.6 A g -1 and excellent cycling stability (94% retention over 1000 cycles). Moreover, porous CuO nanotubes were successfully fabricated by the thermal decomposition of this nanowire precursor. The CuO nanotube exhibits good electrochemical performance with high rate capacity (77% retention at 12.5 A g -1 ) and long-term stability (96% retention over 1000 cycles). The strategy developed here for the synthesis of porous nanowires and nanotubes can be extended to the construction of other electrode materials for more efficient energy storage.

Ultrahigh volumetric capacitance and cyclic stability of fluorine and nitrogen co-doped carbon microspheres

NASA Astrophysics Data System (ADS)

Zhou, Junshuang; Lian, Jie; Hou, Li; Zhang, Junchuan; Gou, Huiyang; Xia, Meirong; Zhao, Yufeng; Strobel, Timothy A.; Tao, Lu; Gao, Faming

2015-09-01

Highly porous nanostructures with large surface areas are typically employed for electrical double-layer capacitors to improve gravimetric energy storage capacity; however, high surface area carbon-based electrodes result in poor volumetric capacitance because of the low packing density of porous materials. Here, we demonstrate ultrahigh volumetric capacitance of 521 F cm-3 in aqueous electrolytes for non-porous carbon microsphere electrodes co-doped with fluorine and nitrogen synthesized by low-temperature solvothermal route, rivaling expensive RuO2 or MnO2 pseudo-capacitors. The new electrodes also exhibit excellent cyclic stability without capacitance loss after 10,000 cycles in both acidic and basic electrolytes at a high charge current of 5 A g-1. This work provides a new approach for designing high-performance electrodes with exceptional volumetric capacitance with high mass loadings and charge rates for long-lived electrochemical energy storage systems.

Large Energy Density, Excellent Thermal Stability, and High Cycling Endurance of Lead-Free BaZr0.2Ti0.8O3 Film Capacitors.

PubMed

Sun, Zixiong; Ma, Chunrui; Wang, Xi; Liu, Ming; Lu, Lu; Wu, Ming; Lou, Xiaojie; Wang, Hong; Jia, Chun-Lin

2017-05-24

A large energy storage density (ESD) of 30.4 J/cm 3 and high energy efficiency of 81.7% under an electrical field of 3 MV/cm was achieved at room temperature by the fabrication of environmentally friendly lead-free BaZr 0.2 Ti 0.8 O 3 epitaxial thin films on Nb-doped SrTiO 3 (001) substrates by using a radio-frequency magnetron sputtering system. Moreover, the BZT film capacitors exhibit great thermal stability of the ESD from 16.8 J/cm 3 to 14.0 J/cm 3 with efficiency of beyond 67.4% and high fatigue endurance (up to 10 6 cycles) in a wide temperature range from room temperature to 125 °C. Compared to other BaTiO 3 -based energy storage capacitor materials and even Pb-based systems, BaZr 0.2 Ti 0.8 O 3 thin film capacitors show either high ESD or great energy efficiency. All of these excellent results revealed that the BaZr 0.2 Ti 0.8 O 3 film capacitors have huge potential in the application of modern electronics, such as locomotive and pulse power, in harsh working environments.

Physicochemical stability, pharmacokinetic, and biodistribution evaluation of paclitaxel solid dispersion prepared using supercritical antisolvent process.

PubMed

Shanmugam, Srinivasan; Park, Jae-Hyun; Chi, Sang-Cheol; Yong, Chul Soon; Choi, Han-Gon; Woo, Jong Soo

2011-06-01

To investigate the physicochemical stability, pharmacokinetics (PK), and biodistribution of paclitaxel (PTX) from paclitaxel solid dispersion (PSD) prepared by supercritical antisolvent (SAS) process. Physicochemical stability was performed in accelerated (40°C 70 ± 5% RH) and stress (60°C) storage conditions for a period of 6 months and 4 weeks, respectively. PK and biodistribution studies were performed in rats following i.v. administration of PTX equivalent to 6 and 12 mg/kg formulations. Physical stability of PSD showed excellent stability with no recrystallization of the amorphous form. Chemical stability of PSD in terms of % PTX remaining was 98.2 ± 0.6% at 6 months and 97.9 ± 0.3% at 4 weeks of accelerated and stress conditions, respectively. The PK study showed a nonlinear increase in AUC with increasing dose, that is, 100% increase in dose (from 6 to 12 mg/kg) resulted in 405.90% increase in AUC. Unlike PK study, the organ distribution study of PTX from PSD showed linear relationship with dose escalation. The order of organ distribution of PTX from highest to lowest for both PSD and Taxol® was liver>kidney>lung>brain. This study demonstrated excellent physicochemical stability with insight information on the PK and biodistribution of PTX from PSD prepared by SAS process.

Mechanical ball-milling preparation of fullerene/cobalt core/shell nanocomposites with high electrochemical hydrogen storage ability.

PubMed

Bao, Di; Gao, Peng; Shen, Xiande; Chang, Cheng; Wang, Longqiang; Wang, Ying; Chen, Yujin; Zhou, Xiaoming; Sun, Shuchao; Li, Guobao; Yang, Piaoping

2014-02-26

The design and synthesis of new hydrogen storage nanomaterials with high capacity at low cost is extremely desirable but remains challenging for today's development of hydrogen economy. Because of the special honeycomb structures and excellent physical and chemical characters, fullerenes have been extensively considered as ideal materials for hydrogen storage materials. To take the most advantage of its distinctive symmetrical carbon cage structure, we have uniformly coated C60's surface with metal cobalt in nanoscale to form a core/shell structure through a simple ball-milling process in this work. The X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, high-solution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrometry (EDX) elemental mappings, and X-ray photoelectron spectroscopy (XPS) measurements have been conducted to evaluate the size and the composition of the composites. In addition, the blue shift of C60 pentagonal pinch mode demonstrates the formation of Co-C chemical bond, and which enhances the stability of the as-obtained nanocomposites. And their electrochemical experimental results demonstrate that the as-obtained C60/Co composites have excellent electrochemical hydrogen storage cycle reversibility and considerably high hydrogen storage capacities of 907 mAh/g (3.32 wt % hydrogen) under room temperature and ambient pressure, which is very close to the theoretical hydrogen storage capacities of individual metal Co (3.33 wt % hydrogen). Furthermore, their hydrogen storage processes and the mechanism have also been investigated, in which the quasi-reversible C60/Co↔C60/Co-Hx reaction is the dominant cycle process.

Niobium Nitride Nb4N5 as a New High‐Performance Electrode Material for Supercapacitors

PubMed Central

Cui, Houlei; Zhu, Guilian; Liu, Xiangye; Liu, Fengxin; Xie, Yian; Yang, Chongyin; Lin, Tianquan; Gu, Hui

2015-01-01

Supercapacitors suffer either from low capacitance for carbon or derivate electrodes or from poor electrical conductivity and electrochemical stability for metal oxide or conducting polymer electrodes. Transition metal nitrides possess fair electrical conductivity but superior chemical stability, which may be desirable candidates for supercapacitors. Herein, niobium nitride, Nb4N5, is explored to be an excellent capacitive material for the first time. An areal capacitance of 225.8 mF cm−2, with a reasonable rate capability (60.8% retention from 0.5 to 10 mA cm−2) and cycling stability (70.9% retention after 2000 cycles), is achieved in Nb4N5 nanochannels electrode with prominent electrical conductivity and electrochemical activity. Faradaic pseudocapacitance is confirmed by the mechanistic studies, deriving from the proton incorporation/chemisorption reaction owing to the copious +5 valence Nb ions in Nb4N5. Moreover, this Nb4N5 nanochannels electrode with an ultrathin carbon coating exhibits nearly 100% capacitance retention after 2000 CV cycles, which is an excellent cycling stability for metal nitride materials. Thus, the Nb4N5 nanochannels are qualified for a candidate for supercapacitors and other energy storage applications. PMID:27980920

Niobium Nitride Nb4N5 as a New High-Performance Electrode Material for Supercapacitors.

PubMed

Cui, Houlei; Zhu, Guilian; Liu, Xiangye; Liu, Fengxin; Xie, Yian; Yang, Chongyin; Lin, Tianquan; Gu, Hui; Huang, Fuqiang

2015-12-01

Supercapacitors suffer either from low capacitance for carbon or derivate electrodes or from poor electrical conductivity and electrochemical stability for metal oxide or conducting polymer electrodes. Transition metal nitrides possess fair electrical conductivity but superior chemical stability, which may be desirable candidates for supercapacitors. Herein, niobium nitride, Nb 4 N 5 , is explored to be an excellent capacitive material for the first time. An areal capacitance of 225.8 mF cm -2 , with a reasonable rate capability (60.8% retention from 0.5 to 10 mA cm -2 ) and cycling stability (70.9% retention after 2000 cycles), is achieved in Nb 4 N 5 nanochannels electrode with prominent electrical conductivity and electrochemical activity. Faradaic pseudocapacitance is confirmed by the mechanistic studies, deriving from the proton incorporation/chemisorption reaction owing to the copious +5 valence Nb ions in Nb 4 N 5 . Moreover, this Nb 4 N 5 nanochannels electrode with an ultrathin carbon coating exhibits nearly 100% capacitance retention after 2000 CV cycles, which is an excellent cycling stability for metal nitride materials. Thus, the Nb 4 N 5 nanochannels are qualified for a candidate for supercapacitors and other energy storage applications.

Three-dimensional hierarchical NiCo2O4 nanowire@Ni3S2 nanosheet core/shell arrays for flexible asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Liu, Bo; Kong, Dezhi; Huang, Zhi Xiang; Mo, Runwei; Wang, Ye; Han, Zhaojun; Cheng, Chuanwei; Yang, Hui Ying

2016-05-01

Three-dimensional (3D) hierarchical NiCo2O4@Ni3S2 core/shell arrays on Ni foam were synthesized by a facile, stepwise synthesis approach. The 3D heterogeneous NiCo2O4 nanostructure forms an interconnected web-like scaffold and serves as the core for the Ni3S2 shell. The as-prepared NiCo2O4@Ni3S2 nanowire array (NWA) electrodes exhibited excellent electrochemical performance, such as high specific areal capacitance and excellent cycling stability. The specific areal capacitance of 3.0 F cm-2 at a current density of 5 mA cm-2 is among the highest values and the only 6.7% capacitance decay after 10 000 cycles demonstrates the excellent cycling stability. A flexible asymmetric supercapacitor (ASC) was fabricated with activated carbon (AC) as the anode and the obtained NiCo2O4@Ni3S2 NWAs as the cathode. The ASC device exhibited a high energy density of 1.89 mW h cm-3 at 5.81 W cm-3 and a high power density of 56.33 W cm-3 at 0.94 mW h cm-3. As a result, the hybrid nanoarchitecture opens a new way to design high performance electrodes for electrochemical energy storage applications.Three-dimensional (3D) hierarchical NiCo2O4@Ni3S2 core/shell arrays on Ni foam were synthesized by a facile, stepwise synthesis approach. The 3D heterogeneous NiCo2O4 nanostructure forms an interconnected web-like scaffold and serves as the core for the Ni3S2 shell. The as-prepared NiCo2O4@Ni3S2 nanowire array (NWA) electrodes exhibited excellent electrochemical performance, such as high specific areal capacitance and excellent cycling stability. The specific areal capacitance of 3.0 F cm-2 at a current density of 5 mA cm-2 is among the highest values and the only 6.7% capacitance decay after 10 000 cycles demonstrates the excellent cycling stability. A flexible asymmetric supercapacitor (ASC) was fabricated with activated carbon (AC) as the anode and the obtained NiCo2O4@Ni3S2 NWAs as the cathode. The ASC device exhibited a high energy density of 1.89 mW h cm-3 at 5.81 W cm-3 and a high power density of 56.33 W cm-3 at 0.94 mW h cm-3. As a result, the hybrid nanoarchitecture opens a new way to design high performance electrodes for electrochemical energy storage applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02600a

Changes in chokeberry (Aronia melanocarpa L.) polyphenols during juice processing and storage.

PubMed

Wilkes, Kail; Howard, Luke R; Brownmiller, Cindi; Prior, Ronald L

2014-05-07

Chokeberries are an excellent source of polyphenols, but their fate during juice processing and storage is unknown. The stability of anthocyanins, total proanthocyanidins, hydroxycinnamic acids, and flavonols at various stages of juice processing and over 6 months of storage at 25 °C was determined. Flavonols, total proanthocyanidins, and hydroxycinnamic acids were retained in the juice to a greater extent than anthocyanins, with losses mostly due to removal of seeds and skins following pressing. Anthocyanins were extensively degraded by thermal treatments during which time levels of protocatechuic acid and phloroglucinaldehyde increased, and additional losses occurred following pressing. Flavonols, total proanthocyanidins, and hydroxycinnamic acids were well retained in juices stored for 6 months at 25 °C, whereas anthocyanins declined linearly. Anthocyanin losses during storage were paralleled by increased polymeric color values, indicating that the small amounts of anthocyanins remaining were present in large part in polymeric forms.

Synergistic effects from graphene and carbon nanotubes endow ordered hierarchical structure foams with a combination of compressibility, super-elasticity and stability and potential application as pressure sensors.

PubMed

Kuang, Jun; Dai, Zhaohe; Liu, Luqi; Yang, Zhou; Jin, Ming; Zhang, Zhong

2015-01-01

Nanostructured carbon material based three-dimensional porous architectures have been increasingly developed for various applications, e.g. sensors, elastomer conductors, and energy storage devices. Maintaining architectures with good mechanical performance, including elasticity, load-bearing capacity, fatigue resistance and mechanical stability, is prerequisite for realizing these functions. Though graphene and CNT offer opportunities as nanoscale building blocks, it still remains a great challenge to achieve good mechanical performance in their microarchitectures because of the need to precisely control the structure at different scales. Herein, we fabricate a hierarchical honeycomb-like structured hybrid foam based on both graphene and CNT. The resulting materials possess excellent properties of combined high specific strength, elasticity and mechanical stability, which cannot be achieved in neat CNT and graphene foams. The improved mechanical properties are attributed to the synergistic-effect-induced highly organized, multi-scaled hierarchical architectures. Moreover, with their excellent electrical conductivity, we demonstrated that the hybrid foams could be used as pressure sensors in the fields related to artificial skin.

Peroxidase-Mimicking Nanozyme with Enhanced Activity and High Stability Based on Metal-Support Interactions.

PubMed

Li, Zhihao; Yang, Xiangdong; Yang, Yanbing; Tan, Yaning; He, Yue; Liu, Meng; Liu, Xinwen; Yuan, Quan

2018-01-09

Peroxidase-mimicking nanozymes offer unique advantages in terms of high stability and low cost over natural peroxidase for applications in bioanalysis, biomedicine, and the treatment of pollution. However, the design of high-efficiency peroxidase-mimicking nanozymes remains a great challenge. In this study, we adopted a structural-design approach through hybridization of cube-CeO 2 and Pt nanoparticles to create a new peroxidase-mimicking nanozyme with high efficiency and excellent stability. Relative to pure cube-CeO 2 and Pt nanoparticles, the as-hybridized Pt/cube-CeO 2 nanocomposites display much improved activities because of the strong metal-support interaction. Meanwhile, the nanocomposites also maintain high catalytic activity after long-term storage and multiple recycling. Based on their excellent properties, Pt/cube-CeO 2 nanocomposites were used to construct high-performance colorimetric biosensors for the sensitive detection of metabolites, including H 2 O 2 and glucose. Our findings highlight opportunities for the development of high-efficiency peroxidase-mimicking nanozymes with potential applications such as diagnostics, biomedicine, and the treatment of pollution. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mesoporous CLEAs-silica composite microparticles with high activity and enhanced stability

PubMed Central

Cui, Jiandong; Jia, Shiru; Liang, Longhao; Zhao, Yamin; Feng, Yuxiao

2015-01-01

A novel enzyme immobilization approach was used to generate mesoporous enzymes-silica composite microparticles by co-entrapping gelatinized starch and cross-linked phenylalanine ammonia lyase (PAL) aggregates (CLEAs) containing gelatinized starch into biomemitic silica and subsequently removing the starch by α-amylase treatment. During the preparation process, the gelatinzed starch served as a pore-forming agent to create pores in CLEAs and biomimetic silica. The resulting mesoporous CLEAs-silica composite microparticles exhibited higher activity and stability than native PAL, conventional CLEAs, and PAL encapsulated in biomimetic silica. Furthermore, the mesoporous CLEAs-silica composite microparticles displayed good reusability due to its suitable size and mechanical properties, and had excellent stability for storage. The superior catalytic performances were attributed to the combinational unique structure from the intra-cross-linking among enzyme aggregates and hard mesoporous silica shell, which not only decreased the enzyme-support negative interaction and mass-transfer limitations, but also improved the mechanical properties and monodispersity. This approach will be highly beneficial for preparing various bioactive mesoporous composites with excellent catalytic performance. PMID:26374188

An amperometric enzyme electrode and its biofuel cell based on a glucose oxidase-poly(3-anilineboronic acid)-Pd nanoparticles bionanocomposite for glucose biosensing.

PubMed

Sun, Lingen; Ma, Yixuan; Zhang, Pei; Chao, Long; Huang, Ting; Xie, Qingji; Chen, Chao; Yao, Shouzhuo

2015-06-01

A new amperometric enzyme electrode and its biofuel cell were fabricated based on a glucose oxidase (GOx)-poly(3-anilineboronic acid) (PABA)-Pd nanoparticles (PdNPs) bionanocomposite for biosensing of glucose. Briefly, Pd was electroplated on a multiwalled carbon nanotubes (MWCNTs)-modified Au electrode, and the GOx-PABA-PdNPs bionanocomposite was prepared on the Pd(plate)/MWCNTs/Au electrode through the chemical oxidation of a GOx-3-anilineboronic acid adduct by Na2PdCl4, followed by electrode-modification with an outer-layer chitosan (CS) film. The thus-prepared CS/GOx-PABA-PdNPs/Pd(plate)/MWCNTs/Au electrode exhibited a linear amperometric response to glucose concentration from 2.0 μM to 4.5 mM with a sensitivity of 160 μA/mM/cm(2), sub-μM detection limit, and excellent operation/storage stability in the first-generation biosensing mode, as well as excellent analytical performance in the second-generation biosensing mode. The good recoveries of glucose obtained from spiked urine samples revealed the application potential of our amperometric enzyme electrode. In addition, a glucose/O2 biofuel cell was constructed using this enzyme electrode as the anode and a Pt/MWCNTs/Au electrode as the cathode, and this biofuel cell as a self-powered biosensing device showed a linear voltage response to glucose concentration from 100 μM to 13.5 mM with a sensitivity of 43.5 mV/mM/cm(2) and excellent operation/storage stability. Copyright © 2015 Elsevier B.V. All rights reserved.

Maillard-Reaction-Functionalized Egg Ovalbumin Stabilizes Oil Nanoemulsions.

PubMed

Liu, Gang; Yuan, Dan; Wang, Qi; Li, Wanrong; Cai, Jie; Li, Shuyi; Lamikanra, Olusola; Qin, Xinguang

2018-04-25

Egg white proteins are an excellent source of nutrition, with high biological and technological values. However, their limited functional properties prevent their widespread industrial applications. In this study, the ovalbumin functionality was improved via glycation by Maillard reaction with d-lactose. The free amino groups and sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile were determined, confirming that glycation occurred between ovalbumin and lactose. The emulsification of the conjugate was 2.69-fold higher than that of ovalbumin at pH 7.0 after glycation. The thermal stability also improved remarkably. The glycated protein products were used to form an oil-water nanoemulsion for polymethoxyflavone-rich aged orange peel oil. The resulting nanoemulsion showed good pH, thermal, and storage stabilities.

Enhanced thermal properties of novel shape-stabilized PEG composite phase change materials with radial mesoporous silica sphere for thermal energy storage.

PubMed

Min, Xin; Fang, Minghao; Huang, Zhaohui; Liu, Yan'gai; Huang, Yaoting; Wen, Ruilong; Qian, Tingting; Wu, Xiaowen

2015-08-11

Radial mesoporous silica (RMS) sphere was tailor-made for further applications in producing shape-stabilized composite phase change materials (ss-CPCMs) through a facile self-assembly process using CTAB as the main template and TEOS as SiO2 precursor. Novel ss-CPCMs composed of polyethylene glycol (PEG) and RMS were prepared through vacuum impregnating method. Various techniques were employed to characterize the structural and thermal properties of the ss-CPCMs. The DSC results indicated that the PEG/RMS ss-CPCM was a promising candidate for building thermal energy storage applications due to its large latent heat, suitable phase change temperature, good thermal reliability, as well as the excellent chemical compatibility and thermal stability. Importantly, the possible formation mechanisms of both RMS sphere and PEG/RMS composite have also been proposed. The results also indicated that the properties of the PEG/RMS ss-CPCMs are influenced by the adsorption limitation of the PEG molecule from RMS sphere with mesoporous structure and the effect of RMS, as the impurities, on the perfect crystallization of PEG.

Enhanced thermal properties of novel shape-stabilized PEG composite phase change materials with radial mesoporous silica sphere for thermal energy storage

PubMed Central

Min, Xin; Fang, Minghao; Huang, Zhaohui; Liu, Yan’gai; Huang, Yaoting; Wen, Ruilong; Qian, Tingting; Wu, Xiaowen

2015-01-01

Radial mesoporous silica (RMS) sphere was tailor-made for further applications in producing shape-stabilized composite phase change materials (ss-CPCMs) through a facile self-assembly process using CTAB as the main template and TEOS as SiO2 precursor. Novel ss-CPCMs composed of polyethylene glycol (PEG) and RMS were prepared through vacuum impregnating method. Various techniques were employed to characterize the structural and thermal properties of the ss-CPCMs. The DSC results indicated that the PEG/RMS ss-CPCM was a promising candidate for building thermal energy storage applications due to its large latent heat, suitable phase change temperature, good thermal reliability, as well as the excellent chemical compatibility and thermal stability. Importantly, the possible formation mechanisms of both RMS sphere and PEG/RMS composite have also been proposed. The results also indicated that the properties of the PEG/RMS ss-CPCMs are influenced by the adsorption limitation of the PEG molecule from RMS sphere with mesoporous structure and the effect of RMS, as the impurities, on the perfect crystallization of PEG. PMID:26261089

Aging behavior of lithium iron phosphate based 18650-type cells studied by in situ neutron diffraction

NASA Astrophysics Data System (ADS)

Paul, Neelima; Wandt, Johannes; Seidlmayer, Stefan; Schebesta, Sebastian; Mühlbauer, Martin J.; Dolotko, Oleksandr; Gasteiger, Hubert A.; Gilles, Ralph

2017-03-01

The aging behavior of commercially produced 18650-type Li-ion cells consisting of a lithium iron phosphate (LFP) based cathode and a graphite anode based on either mesocarbon microbeads (MCMB) or needle coke (NC) is studied by in situ neutron diffraction and standard electrochemical techniques. While the MCMB cells showed an excellent cycle life with only 8% relative capacity loss (i.e., referenced to the capacity after formation) after 4750 cycles and showed no capacity loss on storage for two years, the needle coke cells suffered a 23% relative capacity loss after cycling and a 11% loss after storage. Based on a combination of neutron diffraction and electrochemical characterization, it is shown that the entire capacity loss for both cell types is dominated by the loss of active lithium; no other aging mechanisms like structural degradation of anode or cathode active materials or deactivation of active material could be found, highlighting the high structural stability of the active material and the excellent quality of the investigated cells.

Confined Transformation Derived Ultrathin Titanate Nanosheets/ Graphene Films for Excellent Na/K Ion Storage.

PubMed

Zeng, Cheng; Xie, Fangxi; Yang, Xianfeng; Jaroniec, Mietek; Zhang, Lei; Qiao, Shizhang

2018-05-02

Confined transformation of assembled two-dimensional MXene (titanium carbide) and reduced graphene oxide (rGO) nanosheets was employed to prepare the free-standing films of the integrated ultrathin sodium titanate (NTO)/potassium titanate (KTO) nanosheets sandwiched between graphene layers. The ultrathin Ti-based nanosheets reduce the diffusion distance while rGO layers enhance conductivity. Incorporation of graphene into the titanate films produced efficient binder-free anodes for ion storage. The resulting NTO/rGO electrode for sodium ion batteries exhibited an excellent rate performance and long cycling stability characterized by reversible capacity of 72 mA h g-1 at 5 A g-1 after 10000 cycles. Moreover, flexible KTO/rGO electrode for potassium ion batteries maintained a reversible capacity of 75 mA h g-1 after 700 cycles at 2 A g-1. These results demonstrate the superiority of the unique sandwich-type electrodes. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Galileo probe lithium-sulfur dioxide cell life testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hofland, L.M.; Stofel, E.J.; Taenaka, R.K.

Several hundred D-sized, Li/SO{sub 2} battery cells have been in a carefully controlled quiescent storage test for up to 14 years, starting at Honeywell but completing at the NASA Ames Research Center, in support of the Atmospheric Probe portion of the Galileo Mission to the planet Jupiter. This population of cells includes similar samples from 8 different manufacturing lots; the earliest from October 1981, the latest from October 1988. The baseline samples have been divided among several storage chambers, each having its own constant temperature, respectively set between 0 to 40 C. Non-invasive measurements have been made repeatedly of openmore » circuit voltage and internal resistance (at 1,000 Hz). At intervals, a small portion of the cells has been removed from storage and fully discharged under repetitive conditions, thus assessing any storage related loss of discharge capacity. The results show that for storage up to 20 C the cells have excellent stability. Above 20 C noticeable degradation occurs.« less

Effects of grape seed extract on the oxidative and microbial stability of restructured mutton slices.

PubMed

Reddy, G V Bhaskar; Sen, A R; Nair, Pramod N; Reddy, K Sudhakar; Reddy, K Kondal; Kondaiah, N

2013-10-01

The antioxidant and antimicrobial efficacy of grape seed extract (GSE) was studied in restructured mutton slices (RMS) under aerobic and vacuum packaging conditions during refrigerated storage. The RMS treated with grape seed extract (GSE) had significantly (P<0.05) lower thiobarbituric acid reactive substance (TBARS) values and free fatty acids (FFA) % compared to control (C) and butylated hydroxy anisole (BHA) treated RMS during storage at 4±1°C. Addition of GSE significantly (P<0.05) reduced the total psychrophilic and coliform counts in RMS during refrigerated storage. The GSE treated mutton slices recorded significantly (P<0.05) superior scores of color, flavor, juiciness and overall palatability than C and BHA treated RMS. The TBARS values, FFA % and microbial counts increased significantly (P<0.05) during storage. It can be concluded that GSE has excellent antioxidant and antimicrobial properties compared to control and BHA treated RMS during refrigerated storage under aerobic and vacuum conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Numerical Simulations, Mean Field Theory and Modulational Stability Analysis of Thermohaline Intrusions

DTIC Science & Technology

2011-09-01

on the exchange and storage of freshwater. It is an excellent tracer of circulation, which is 3 important in the redistribution of heat and carbon ... dioxide . The Climate Variability and Predictability Program (CLIVAR) was created to investigate the “slowly varying components of the climate...fingers in the thermocline of the tropical Atlantic. Science Magazine, 308, 685–688. Schmitt, R. W., 1979: The growth rate of supercritical salt

Interfacial film stabilized W/O/W nano multiple emulsions loaded with green tea and lotus extracts: systematic characterization of physicochemical properties and shelf-storage stability

PubMed Central

2014-01-01

Background and aims Multiple emulsions have excellent encapsulating potential and this investigation has been aimed to encapsulate two different plant extracts as functional cosmetic agents in the W/O/W multiple emulsions and the resultant system’s long term stability has been determined in the presence of a thickener, hydroxypropyl methylcellulose (HPMC). Methods Multiple W/O/W emulsions have been generated using cetyl dimethicone copolyol as lipophilic emulsifier and a blend of polyoxyethylene (20) cetyl ether and cetomacrogol 1000® as hydrophilic emulsifiers. The generated multiple emulsions have been characterized with conductivity, pH, microscopic analysis, phase separation and rheology for a period of 30 days. Moreover, long term shelf-storage stability has been tested to understand the shelf-life by keeping the generated multiple emulsion formulations at 25 ± 10°C and at 40 ± 10% relative humidity for a period of 12 months. Results It has been observed that the hydrophilic emulsifiers and HPMC have considerably improved the stability of multiple emulsions for the followed period of 12 months at different storage conditions. These multiple emulsions have shown improved entrapment efficiencies concluded on the release rate of conductometric tracer entrapped in the inner aqueous phase of the multiple emulsions. Conclusion Multiple emulsions have been found to be stable for a longer period of time with promising characteristics. Hence, stable multiple emulsions loaded with green tea and lotus extracts could be explored for their cosmetic benefits. PMID:24885994

Highly transparent and thermal-stable silver nanowire conductive film covered with ZnMgO by atomic-layer-deposition

NASA Astrophysics Data System (ADS)

Wang, Lei; Huang, Dongchen; Li, Min; Xu, Hua; Zou, Jianhua; Tao, Hong; Peng, Junbiao; Xu, Miao

2017-12-01

Solution-processed silver nanowires (AgNWs) have been considered as a promising material for next generation flexible transparent conductive electrodes. However AgNWs films have several intrinsic drawbacks, such as thermal stability and storage stability. Herein, we demonstrate a laminated ZnO/MgO (ZnMgO, ZMO) as a protective layer on the AgNWs films using atomic layer deposition (ALD). The fabricated films exhibited a low sheet resistance of 16 Ω/sq with high transmittance of 91% at 550 nm, an excellent thermal stability and bending property. The ZMO film grows perpendicularly on the surface of the AgNWs, making a perfect coverage of bulk silver nanowires and junction, which can effectively prompt the electrical transport behavior and enhance stability of the silver nanowires network.

All-solid-state flexible supercapacitors based on highly dispersed polypyrrole nanowire and reduced graphene oxide composites.

PubMed

Yu, Chenfei; Ma, Peipei; Zhou, Xi; Wang, Anqi; Qian, Tao; Wu, Shishan; Chen, Qiang

2014-10-22

Highly dispersed polypyrrole nanowires are decorated on reduced graphene oxide sheets using a facile in situ synthesis route. The prepared composites exhibit high dispersibility, large effective surface area, and high electric conductivity. All-solid-state flexible supercapacitors are assembled based on the prepared composites, which show excellent electrochemical performances with a specific capacitance of 434.7 F g(-1) at a current density of 1 A g(-1). The as-fabricated supercapacitor also exhibits excellent cycling stability (88.1% capacitance retention after 5000 cycles) and exceptional mechanical flexibility. In addition, outstanding power and energy densities were obtained, demonstrating the significant potential of prepared material for flexible and portable energy storage devices.

Novel Conjugated Ladder-Structured Oligomer Anode with High Lithium Storage and Long Cycling Capability.

PubMed

Xie, Jian; Rui, Xianhong; Gu, Peiyang; Wu, Jiansheng; Xu, Zhichuan J; Yan, Qingyu; Zhang, Qichun

2016-07-06

Herein we report the development of nanostructured poly(1,4-dihydro-11H-pyrazino[2',3':3,4]cyclopenta[1,2-b]quinoxalin-11-one) (PPCQ), a novel conjugated ladderlike oligomer with the presence of a rich amount of heteroatoms, as the anode material. Beyond its remarkable lithium storage of 972 mAh g(-1) after 120 cycles, the superior cycle life and stable capacity performance of 489 mAh g(-1) revealed by ultralong testing of 1000 cycles (with an average Coulombic efficiency 99.8%) at a high current density of 2.5 A g(-1) indicate its excellent electrochemical stability to be promisingly applied for high-performance lithium-ion batteries (LIBs).

Flexible graphene/carbon nanotube hybrid papers chemical-reduction-tailored by gallic acid for high-performance electrochemical capacitive energy storages

NASA Astrophysics Data System (ADS)

Yao, Lu; Zhou, Chao; Hu, Nantao; Hu, Jing; Hong, Min; Zhang, Liying; Zhang, Yafei

2018-03-01

Mechanically robust graphene papers with both high gravimetric and volumetric capacitances are desired for high-performance energy storages. However, it's still a challenge to tailor the structure of graphene papers in order to meet this requirement. In this work, a kind of chemical-reduction-tailored mechanically-robust reduced graphene oxide/carbon nanotube hybrid paper has been reported for high-performance electrochemical capacitive energy storages. Gallic acid (GA), as an excellent reducing agent, was used to reduce graphene oxide. Through vacuum filtration of gallic acid reduced graphene oxide (GA-rGO) and carboxylic multiwalled carbon nanotubes (MWCNTs) aqueous suspensions, mechanically robust GA-rGO/MWCNTs hybrid papers were obtained. The resultant hybrid papers showed high gravimetric capacitance of 337.6 F g-1 (0.5 A g-1) and volumetric capacitance of 151.2 F cm-3 (0.25 A cm-3). In addition, the assembled symmetric device based on the hybrid papers exhibited high gravimetric capacitance of 291.6 F g-1 (0.5 A g-1) and volumetric capacitance of 136.6 F cm-3 (0.25 A cm-3). Meanwhile, it exhibited excellent rate capability and cycling stability. Above all, this chemical reduction tailoring technique and the resultant high-performance GA-rGO/MWCNTs hybrid papers give an insight for designing high-performance electrodes and hold a great potential in the field of energy storages.

Toward highly stable solid-state unconventional thin-film battery-supercapacitor hybrid devices: Interfacing vertical core-shell array electrodes with a gel polymer electrolyte

NASA Astrophysics Data System (ADS)

Pandey, Gaind P.; Klankowski, Steven A.; Liu, Tao; Wu, Judy; Li, Jun

2017-02-01

A novel solid-state battery-supercapacitor hybrid device is fabricated for high-performance electrical energy storage using a Si anode and a TiO2 cathode in conjunction with a flexible, solid-like gel polymer electrolyte film as the electrolyte and separator. The electrodes were fabricated as three-dimensional nanostructured vertical arrays by sputtering active materials as conformal shells on vertically aligned carbon nanofibers (VACNFs) which serve as the current collector and structural template. Such nanostructured vertical core-shell array-electrodes enable short Li-ion diffusion path and large pseudocapacitive contribution by fast surface reactions, leading to the hybrid features of batteries and supercapacitors that can provide high specific energy over a wide range of power rates. Due to the improved mechanical stability of the infiltrated composite structure, the hybrid cell shows excellent cycling stability and is able to retain more than 95% of the original capacity after 3500 cycles. More importantly, this solid-state device can stably operate in a temperature range from -20 to 60 °C with a very low self-discharge rate and an excellent shelf life. This solid-state architecture is promising for the development of highly stable thin-film hybrid energy storage devices for unconventional applications requiring largely varied power, wider operation temperature, long shelf-life and higher safety standards.

High-Performance Biomass-Based Flexible Solid-State Supercapacitor Constructed of Pressure-Sensitive Lignin-Based and Cellulose Hydrogels.

PubMed

Peng, Zhiyuan; Zou, Yubo; Xu, Shiqi; Zhong, Wenbin; Yang, Wantai

2018-06-19

Employing renewable, earth-abundant, environmentally friendly, low-cost natural materials to design flexible supercapacitors (FSCs) as energy storage devices in wearable/portable electronics represents the global perspective to build sustainable and green society. Chemically stable and flexible cellulose and electroactive lignin have been employed to construct a biomass-based FSC for the first time. The FSC was assembled using lignosulfonate/single-walled carbon nanotube HNO 3 (Lig/SWCNT HNO 3 ) pressure-sensitive hydrogels as electrodes and cellulose hydrogels as an electrolyte separator. The assembled biomass-based FSC shows high specific capacitance (292 F g -1 at a current density of 0.5 A g -1 ), excellent rate capability, and an outstanding energy density of 17.1 W h kg -1 at a power density of 324 W kg -1 . Remarkably, the FSC presents outstanding electrochemical stability even suffering 1000 bending cycles. Such excellent flexibility, stability, and electrochemical performance enable the designed biomass-based FSCs as prominent candidates in applications of wearable electronic devices.

Preparation of Glucose Sensor Using Polydimethylsiloxane / Polypyrrole Complex

NASA Astrophysics Data System (ADS)

Yasuzawa, Mikito; Inoue, Shigeru; Imai, Shinji

New glucose oxidase (GOD) immobilized glucose sensors were prepared by the electropolymerization of 1-(6-D-gluconamidohexyl) pyrrole (GHP) on the platinum wire electrode precoated with the mixture solution of pyrrole derivative GHP, polydimethylsiloxane (PDS) and Nafion. The addition of Nafion into the precoating mixture solution was essential to obtain suitable sensor sensitivity. However, the sensitivity was about the half of that of the electrode without PDS precoating. Although, the introduction of Nafion was effective to improve the long-term stability of the enzyme-immobilized electrode, the electrode prepared using Nafion, PDS and GHP performed excellent long-term stability even at the measurement and storage temperatures of 40°C. Relatively constant response current was obtained over 30 days under the condition of 40°C and over 9 months measured at 25°C. Moreover, the GOD-immobilized GHP polymer film prepared on the electrode precoated with GHP, PDS and Nafion solution, was found to have excellent hemocompatibility from the result of platelet rich plasma contacting test.

Rapid Recovery of Clofazimine-Loaded Nanoparticles with Long-Term Storage Stability as Anti-Cryptosporidium Therapy.

PubMed

Feng, Jie; Zhang, Yingyue; McManus, Simon A; Ristroph, Kurt D; Lu, Hoang D; Gong, Kai; White, Claire E; Prud'homme, Robert K

2018-05-25

While the formulation of nanoparticle (NP) suspensions has been widely applied in materials and life science, the recovery of NPs from such a suspension into a solid state is practically important to confer long-term storage stability. However, solidification, while preserving the original nanoscale properties, remains a formidable challenge in the pharmaceutical and biomedical applications of NPs. Herein we combined flash nanoprecipitation (FNP) and spray-drying as a nanofabrication platform for NP formulation and recovery without compromising the dissolution kinetics of the active ingredient. Clofazimine was chosen to be the representative drug, which has been recently repurposed as a potential treatment for cryptosporidiosis. Clofazimine was encapsulated in NPs with low-cost surface coatings, hypromellose acetate succinate (HPMCAS) and lecithin, which were required by the ultimate application to global health. Spray-drying and lyophilization were utilized to produce dried powders with good long-term storage stability for application in hot and humid climatic zones. The particle morphology, yield efficiency, drug loading, and clofazimine crystallinity in the spray-dried powders were characterized. The in vitro release kinetics of spray-dried NP powders were compared to analogous dissolution profiles from standard lyophilized NP samples, crystalline clofazimine powder, and the commercially available formulation Lamprene. The spray-dried powders showed a supersaturation level of up to 60 times the equilibrium solubility and remarkably improved dissolution rates. In addition, the spray-dried powders with both surface coatings showed excellent stability during aging studies with elevated temperature and humidity, in view of the dissolution and release in vitro. Considering oral delivery for pediatric administration, the spray-dried powders show less staining effects with simulated skin than crystalline clofazimine and may be made into minitablets without additional excipients. These results highlight the potential of combining FNP and spray-drying as a feasible and versatile platform to design and rapidly recover amorphous NPs in a solid dosage form, with the advantages of satisfactory long-term storage stability, low cost, and easy scalability.

Stabilization of Phenylalanine Ammonia Lyase from Rhodotorula glutinis by Encapsulation in Polyethyleneimine-Mediated Biomimetic Silica.

PubMed

Cui, Jiandong; Liang, Longhao; Han, Cong; Lin Liu, Rong

2015-06-01

Phenylalanine ammonia lyase (PAL) from Rhodotorula glutinis was encapsulated within polyethyleneimine-mediated biomimetic silica. The main factors in the preparation of biomimetic silica were optimized by response surface methodology (RSM). Compared to free PAL (about 2 U), the encapsulated PAL retained more than 43 % of their initial activity after 1 h of incubation time at 60 °C, whereas free PAL lost most of activity in the same conditions. It was clearly indicated that the thermal stability of PAL was improved by encapsulation. Moreover, the encapsulated PAL exhibited the excellent stability of the enzyme against denaturants and storage stability, and pH stability was improved by encapsulation. Operational stability of 7 reaction cycles showed that the encapsulated PAL was stable. Nevertheless, the K m value of encapsulated PAL in biomimetic silica was higher than that of the free PAL due to lower total surface area and increased mass transfer resistance.

Phase Restructuring in Transition Metal Dichalcogenides for Highly Stable Energy Storage.

PubMed

Leng, Kai; Chen, Zhongxin; Zhao, Xiaoxu; Tang, Wei; Tian, Bingbing; Nai, Chang Tai; Zhou, Wu; Loh, Kian Ping

2016-09-28

Achieving homogeneous phase transition and uniform charge distribution is essential for good cycle stability and high capacity when phase conversion materials are used as electrodes. Herein, we show that chemical lithiation of bulk 2H-MoS 2 distorts its crystalline domains in three primary directions to produce mosaic-like 1T' nanocrystalline domains, which improve phase and charge uniformity during subsequent electrochemical phase conversion. 1T'-Li x MoS 2 , a macroscopic dense material with interconnected nanoscale grains, shows excellent cycle stability and rate capability in a lithium rechargeable battery compared to bulk or exfoliated-restacked MoS 2 . Transmission electron microscopy studies reveal that the interconnected MoS 2 nanocrystals created during the phase change process are reformable even after multiple cycles of galvanostatic charging/discharging, which allows them to play important roles in the long term cycling performance of the chemically intercalated TMD materials. These studies shed light on how bulk TMDs can be processed into quasi-2D nanophase material for stable energy storage.

Fully Printed Ultraflexible Supercapacitor Supported by a Single-Textile Substrate.

PubMed

Zhang, Huihui; Qiao, Yan; Lu, Zhisong

2016-11-30

Textile-based supercapacitors have recently attracted much attention owing to their great potential as energy storage components in wearable electronics. However, fabrication of a high-performance, fully printed, and ultraflexible supercapacitor based on a single textile still remains a great challenge. Herein, a facile, low-cost, and textile-compatible method involving screen printing and transfer printing is developed to construct all-solid-state supercapacitors on a single silk fabric. The system exhibits a high specific capacitance of 19.23 mF cm -2 at a current density of 1 mA cm -2 and excellent cycling stability with capacitance retention of 84% after 2000 charging/discharging cycles. In addition, the device possesses superior mechanical stability with stable performance and structures after 100 times of bending and twisting. A butterfly-patterned supercapacitor was manufactured to demonstrate the compatibility of the printing approaches to textile aesthetics. This work may provide a facile and versatile approach for fabricating rationally designed ultraflexible textile-based power-storage elements for potential applications in smart textiles and stretchable/flexible electronics.

A low cost, all-organic Na-ion Battery Based on Polymeric Cathode and Anode

PubMed Central

Deng, Wenwen; Liang, Xinmiao; Wu, Xianyong; Qian, Jiangfeng; Cao, Yuliang; Ai, Xinping; Feng, Jiwen; Yang, Hanxi

2013-01-01

Current battery systems have severe cost and resource restrictions, difficultly to meet the large scale electric storage applications. Herein, we report an all-organic Na-ion battery using p-dopable polytriphenylamine as cathode and n-type redox-active poly(anthraquinonyl sulphide) as anode, excluding the use of transition-metals as in conventional electrochemical batteries. Such a Na-ion battery can work well with a voltage output of 1.8 V and realize a considerable specific energy of 92 Wh kg−1. Due to the structural flexibility and stability of the redox-active polymers, this battery has a superior rate capability with 60% capacity released at a very high rate of 16 C (3200 mA g−1) and also exhibit an excellent cycling stability with 85% capacity retention after 500 cycles at 8 C rate. Most significantly, this type of all-organic batteries could be made from renewable and earth-abundant materials, thus offering a new possibility for widespread energy storage applications. PMID:24036973

Egg-Box Structure in Cobalt Alginate: A New Approach to Multifunctional Hierarchical Mesoporous N-Doped Carbon Nanofibers for Efficient Catalysis and Energy Storage.

PubMed

Li, Daohao; Lv, Chunxiao; Liu, Long; Xia, Yanzhi; She, Xilin; Guo, Shaojun; Yang, Dongjiang

2015-08-26

Carbon nanomaterials with both doped heteroatom and porous structure represent a new class of carbon nanostructures for boosting electrochemical application, particularly sustainable electrochemical energy conversion and storage applications. We herein demonstrate a unique large-scale sustainable biomass conversion strategy for the synthesis of earth-abundant multifunctional carbon nanomaterials with well-defined doped heteroatom level and multimodal pores through pyrolyzing electrospinning renewable natural alginate. The key part for our chemical synthesis is that we found that the egg-box structure in cobalt alginate nanofiber can offer new opportunity to create large mesopores (∼10-40 nm) on the surface of nitrogen-doped carbon nanofibers. The as-prepared hierarchical carbon nanofibers with three-dimensional pathway for electron and ion transport are conceptually new as high-performance multifunctional electrochemical materials for boosting the performance of oxygen reduction reaction (ORR), lithium ion batteries (LIBs), and supercapacitors (SCs). In particular, they show amazingly the same ORR activity as commercial Pt/C catalyst and much better long-term stability and methanol tolerance for ORR than Pt/C via a four-electron pathway in alkaline electrolyte. They also exhibit a large reversible capacity of 625 mAh g(-1) at 1 A g(-1), good rate capability, and excellent cycling performance for LIBs, making them among the best in all the reported carbon nanomaterials. They also represent highly efficient carbon nanomaterials for SCs with excellent capacitive behavior of 197 F g(-1) at 1 A g(-1) and superior stability. The present work highlights the importance of biomass-derived multifunctional mesoporous carbon nanomaterials in enhancing electrochemical catalysis and energy storage.

Egg-Box Structure in Cobalt Alginate: A New Approach to Multifunctional Hierarchical Mesoporous N-Doped Carbon Nanofibers for Efficient Catalysis and Energy Storage

PubMed Central

2015-01-01

Carbon nanomaterials with both doped heteroatom and porous structure represent a new class of carbon nanostructures for boosting electrochemical application, particularly sustainable electrochemical energy conversion and storage applications. We herein demonstrate a unique large-scale sustainable biomass conversion strategy for the synthesis of earth-abundant multifunctional carbon nanomaterials with well-defined doped heteroatom level and multimodal pores through pyrolyzing electrospinning renewable natural alginate. The key part for our chemical synthesis is that we found that the egg-box structure in cobalt alginate nanofiber can offer new opportunity to create large mesopores (∼10–40 nm) on the surface of nitrogen-doped carbon nanofibers. The as-prepared hierarchical carbon nanofibers with three-dimensional pathway for electron and ion transport are conceptually new as high-performance multifunctional electrochemical materials for boosting the performance of oxygen reduction reaction (ORR), lithium ion batteries (LIBs), and supercapacitors (SCs). In particular, they show amazingly the same ORR activity as commercial Pt/C catalyst and much better long-term stability and methanol tolerance for ORR than Pt/C via a four-electron pathway in alkaline electrolyte. They also exhibit a large reversible capacity of 625 mAh g–1 at 1 A g–1, good rate capability, and excellent cycling performance for LIBs, making them among the best in all the reported carbon nanomaterials. They also represent highly efficient carbon nanomaterials for SCs with excellent capacitive behavior of 197 F g–1 at 1 A g–1 and superior stability. The present work highlights the importance of biomass-derived multifunctional mesoporous carbon nanomaterials in enhancing electrochemical catalysis and energy storage. PMID:27162980

β-Cobalt sulfide nanoparticles decorated graphene composite electrodes for high capacity and power supercapacitors

NASA Astrophysics Data System (ADS)

Qu, Baihua; Chen, Yuejiao; Zhang, Ming; Hu, Lingling; Lei, Danni; Lu, Bingan; Li, Qiuhong; Wang, Yanguo; Chen, Libao; Wang, Taihong

2012-11-01

Electrochemical supercapacitors have drawn much attention because of their high power and reasonably high energy densities. However, their performances still do not reach the demand of energy storage. In this paper β-cobalt sulfide nanoparticles were homogeneously distributed on a highly conductive graphene (CS-G) nanocomposite, which was confirmed by transmission electron microscopy analysis, and exhibit excellent electrochemical performances including extremely high values of specific capacitance (~1535 F g-1) at a current density of 2 A g-1, high-power density (11.98 kW kg-1) at a discharge current density of 40 A g-1 and excellent cyclic stability. The excellent electrochemical performances could be attributed to the graphene nanosheets (GNSs) which could maintain the mechanical integrity. Also the CS-G nanocomposite electrodes have high electrical conductivity. These results indicate that high electronic conductivity of graphene nanocomposite materials is crucial to achieving high power and energy density for supercapacitors.

β-Cobalt sulfide nanoparticles decorated graphene composite electrodes for high capacity and power supercapacitors.

PubMed

Qu, Baihua; Chen, Yuejiao; Zhang, Ming; Hu, Lingling; Lei, Danni; Lu, Bingan; Li, Qiuhong; Wang, Yanguo; Chen, Libao; Wang, Taihong

2012-12-21

Electrochemical supercapacitors have drawn much attention because of their high power and reasonably high energy densities. However, their performances still do not reach the demand of energy storage. In this paper β-cobalt sulfide nanoparticles were homogeneously distributed on a highly conductive graphene (CS-G) nanocomposite, which was confirmed by transmission electron microscopy analysis, and exhibit excellent electrochemical performances including extremely high values of specific capacitance (~1535 F g(-1)) at a current density of 2 A g(-1), high-power density (11.98 kW kg(-1)) at a discharge current density of 40 A g(-1) and excellent cyclic stability. The excellent electrochemical performances could be attributed to the graphene nanosheets (GNSs) which could maintain the mechanical integrity. Also the CS-G nanocomposite electrodes have high electrical conductivity. These results indicate that high electronic conductivity of graphene nanocomposite materials is crucial to achieving high power and energy density for supercapacitors.

Tunneled Mesoporous Carbon Nanofibers with Embedded ZnO Nanoparticles for Ultrafast Lithium Storage.

PubMed

An, Geon-Hyoung; Lee, Do-Young; Ahn, Hyo-Jin

2017-04-12

Carbon and metal oxide composites have received considerable attention as anode materials for Li-ion batteries (LIBs) owing to their excellent cycling stability and high specific capacity based on the chemical and physical stability of carbon and the high theoretical specific capacity of metal oxides. However, efforts to obtain ultrafast cycling stability in carbon and metal oxide composites at high current density for practical applications still face important challenges because of the longer Li-ion diffusion pathway, which leads to poor ultrafast performance during cycling. Here, tunneled mesoporous carbon nanofibers with embedded ZnO nanoparticles (TMCNF/ZnO) are synthesized by electrospinning, carbonization, and postcalcination. The optimized TMCNF/ZnO shows improved electrochemical performance, delivering outstanding ultrafast cycling stability, indicating a higher specific capacity than previously reported ZnO-based anode materials in LIBs. Therefore, the unique architecture of TMCNF/ZnO has potential for use as an anode material in ultrafast LIBs.

Extra-weak chemiluminescence produced by autoxidation of kampo extract preparations stored in heat-stressed conditions.

PubMed

Sato, H; Hirayama, H; Yamamoto, T; Ishizawa, F; Mizugaki, M

1998-06-01

The purpose of this study was to evaluate the usefulness of extra-weak chemiluminescence (CL) measurement as a rapid method to estimate the stability of Kampo extract preparations. It was found that the Kampo drugs that emit little CL were stable, while those with higher CL were comparatively unstable with regard to the various stability markers, including change of coloration (browning), contents of specific ingredients, high molecular compounds, amino acids and sugars under various conditions of heat storage. Excellent correlation existed between the CL of Kampo drugs and the coloration (delta E* (ab)) and the other above-mentioned evaluation markers. From this investigation, it was deduced that the CL of Kampo drugs originates in the early stage of the Maillard reaction and reflects the stability of the preparations, and that CL is useful for estimating the stability of Kampo drugs.

Free-standing and flexible organic cathode based on aromatic carbonyl compound/carbon nanotube composite for lithium and sodium organic batteries.

PubMed

Yuan, Chenpei; Wu, Qiong; Shao, Qi; Li, Qiang; Gao, Bo; Duan, Qian; Wang, Heng-Guo

2018-05-01

Free-standing and flexible organic cathode based on aromatic carbonyl compound/carbon nanotubes (CNTs) has been successfully synthesized by a simple vacuum filtration strategy. The obtained flexible and free-standing film could be directly used as the binder-, additive- and current collector-free cathode for lithium ion batteries (LIBs) and sodium ion batteries (SIBs). Benefitting from the synergistic effect provided by the aromatic carbonyl compound and CNTs, the flexible organic cathode shows excellent lithium and sodium storage properties, including high reversible capacity (∼150 mAh g -1 at 50 mA g -1 for LIBs and 57.8 mAh g -1 at 25 mA g -1 for SIBs), excellent cycling stability (over 500 cycles for LIBs and 300 cycles for SIBs) and good rate capability (48 mAh g -1 even at 2000 mA g -1 for LIBs and 48 mAh g -1 even at 1000 mA g -1 for SIBs). In view of the simple preparation process and excellent performance, the proposed strategy might open new avenues for the design of high-performance flexible organic electrode for the application in energy storage and conversion. Copyright © 2018 Elsevier Inc. All rights reserved.

Pseudocapacitive Sodium Storage by Ferroelectric Sn2 P2 S6 with Layered Nanostructure.

PubMed

Huang, Sheng; Meng, Chao; Xiao, Min; Ren, Shan; Wang, Shuanjin; Han, Dongmei; Li, Yuning; Meng, Yuezhong

2018-04-19

Sodium ion batteries (SIB) are considered promising alternative candidates for lithium ion batteries (LIB) because of the wide availability and low cost of sodium, therefore the development of alternative sodium storage materials with comparable performance to LIB is urgently desired. The sodium ions with larger sizes resist intercalation or alloying because of slow reaction kinetics. Most pseudocapacitive sodium storage materials are based on subtle nanomaterial engineering, which is difficult for large-scale production. Here, ferroelectric Sn 2 P 2 S 6 with layered nanostructure is developed as sodium ion storage material. The ferroelectricity-enhanced pseudocapacitance of sodium ion in the interlayer spacing makes the electrochemical reaction easier and faster, endowing the Sn 2 P 2 S 6 electrode with excellent rate capability and cycle stability. Furthermore, the facile solid state reaction synthesis and common electrode fabrication make the Sn 2 P 2 S 6 that becomes a promising anode material of SIB. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graetz, Jason

Hydrogen, the most abundant element in the universe, burns excellently and cleanly, with only pure water as a byproduct. NASA has used hydrogen as fuel for years in the space program. So, why not use hydrogen to fuel cars? The bottleneck of developing hydrogen-fueled vehicles has been identified: the greatest problem is storage. The conventional storage method, compressed hydrogen gas, requires a large tank volume, and the possibility of a tank rupture poses a significant safety risk. Another method, low temperature liquid storage, is expensive and impractical for most automotive applications. An alternative is to store the hydrogen in themore » solid state. In his talk, Jason Graetz will describe the new approaches to hydrogen storage being studied by his group at BNL. These include using kinetically stabilized hydrides, bialkali alanates and reversible metal-organic hydrides. The researchers are also using novel synthesis approaches, state-of-the-art characterization and first principles modeling, all providing a better fundamental understanding of these interesting and useful new materials.« less

Novel layered polyaniline-poly(hydroquinone)/graphene film as supercapacitor electrode with enhanced rate performance and cycling stability.

PubMed

Ren, Lijun; Zhang, Gaini; Lei, Ji; Wang, Yan; Hu, Dengwei

2018-02-15

It is a challenge to fabricate polyaniline (PANI) materials with high rate performance and excellent stability. Herein a new special supercapacitor electrode material of polyaniline-poly(hydroquinone)/graphene (PANI-PHQ/RGO) film with layered structure was prepared by chemical oxidative polymerization of aniline and hydroquinone (H 2 Q) in the presence of RGO hydrogel film. The synergistic effect and loose layered structure of the composite film facilitate fast diffusion and transportation of electrolyte ions through unimpeded channels during rapid charge-discharge process, resulting in high rate capability and stable cycling performance. As a result, the PANI-PHQ/RGO-61 film electrode exhibited 356 F g -1 at a current density of 0.5 A g -1 and high capacitance retention of 83% from 0.5 to 30 A g -1 . Moreover, it presented an excellent cycling stability with 94% of capacitance retention in comparison with 60% of pure PANI electrode and an outstanding Coulombic efficiency of 99% after 1000 cycles of galvanostatic charge-discharge. These superior electrocapacitive properties make it one of promising candidates for electrochemical energy storage. Copyright © 2017 Elsevier Inc. All rights reserved.

Multifunctional CNT-polymer composites for ultra-tough structural supercapacitors and desalination devices.

PubMed

Benson, Jim; Kovalenko, Igor; Boukhalfa, Sofiane; Lashmore, David; Sanghadasa, Mohan; Yushin, Gleb

2013-12-03

Pulsed electrodeposition of polyaniline (PANI) allows the fabrication of flexible, electrically conductive, nonwoven PANI-carbon nanotube (PANI-CNT) composite fabrics. They possess specific tensile strength and a modulus of toughness higher than that of aluminum matrix composites, titanium and aluminum alloys, steels, and many other structural materials. Electrochemical tests show that these nanocomposites additionally offer excellent cycle stability and ion electro-sorption and storage properties. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

MnO Nanoparticle@Mesoporous Carbon Composites Grown on Conducting Substrates Featuring High-performance Lithium-ion Battery, Supercapacitor and Sensor

PubMed Central

Wang, Tianyu; Peng, Zheng; Wang, Yuhang; Tang, Jing; Zheng, Gengfeng

2013-01-01

We demonstrate a facile, two-step coating/calcination approach to grow a uniform MnO nanoparticle@mesoporous carbon (MnO@C) composite on conducting substrates, by direct coating of the Mn-oleate precursor solution without any conducting/binding reagents, and subsequent thermal calcination. The monodispersed, sub-10 nm MnO nanoparticles offer high theoretical energy storage capacities and catalytic properties, and the mesoporous carbon coating allows for enhanced electrolyte transport and charge transfer towards/from MnO surface. In addition, the direct growth and attachment of the MnO@C nanocomposite in the supporting conductive substrates provide much reduced contact resistances and efficient charge transfer. These excellent features allow the use of MnO@C nanocomposites as lithium-ion battery and supercapacitor electrodes for energy storage, with high reversible capacity at large current densities, as well as excellent cycling and mechanical stabilities. Moreover, this MnO@C nanocomposite has also demonstrated a high sensitivity for H2O2 detection, and also exhibited attractive potential for the tumor cell analysis. PMID:24045767

Hierarchical nanostructured conducting polymer hydrogel with high electrochemical activity

PubMed Central

Pan, Lijia; Yu, Guihua; Zhai, Dongyuan; Lee, Hye Ryoung; Zhao, Wenting; Liu, Nian; Wang, Huiliang; Tee, Benjamin C.-K.; Shi, Yi; Cui, Yi; Bao, Zhenan

2012-01-01

Conducting polymer hydrogels represent a unique class of materials that synergizes the advantageous features of hydrogels and organic conductors and have been used in many applications such as bioelectronics and energy storage devices. They are often synthesized by polymerizing conductive polymer monomer within a nonconducting hydrogel matrix, resulting in deterioration of their electrical properties. Here, we report a scalable and versatile synthesis of multifunctional polyaniline (PAni) hydrogel with excellent electronic conductivity and electrochemical properties. With high surface area and three-dimensional porous nanostructures, the PAni hydrogels demonstrated potential as high-performance supercapacitor electrodes with high specific capacitance (∼480 F·g-1), unprecedented rate capability, and cycling stability (∼83% capacitance retention after 10,000 cycles). The PAni hydrogels can also function as the active component of glucose oxidase sensors with fast response time (∼0.3 s) and superior sensitivity (∼16.7 μA·mM-1). The scalable synthesis and excellent electrode performance of the PAni hydrogel make it an attractive candidate for bioelectronics and future-generation energy storage electrodes. PMID:22645374

High Performance Hybrid Energy Storage with Potassium Ferricyanide Redox Electrolyte.

PubMed

Lee, Juhan; Choudhury, Soumyadip; Weingarth, Daniel; Kim, Daekyu; Presser, Volker

2016-09-14

We demonstrate stable hybrid electrochemical energy storage performance of a redox-active electrolyte, namely potassium ferricyanide in aqueous media in a supercapacitor-like setup. Challenging issues associated with such a system are a large leakage current and high self-discharge, both stemming from ion redox shuttling through the separator. The latter is effectively eliminated when using an ion exchange membrane instead of a porous separator. Other critical factors toward the optimization of a redox-active electrolyte system, especially electrolyte concentration and volume of electrolyte, have been studied by electrochemical methods. Finally, excellent long-term stability is demonstrated up to 10 000 charge/discharge cycles at 1.2 and 1.8 V, with a broad maximum stability window of up to 1.8 V cell voltage as determined via cyclic voltammetry. An energy capacity of 28.3 Wh/kg or 11.4 Wh/L has been obtained from such cells, taking the nonlinearity of the charge-discharge profile into account. The power performance of our cell has been determined to be 7.1 kW/kg (ca. 2.9 kW/L or 1.2 kW/m(2)). These ratings are higher compared to the same cell operated in aqueous sodium sulfate. This hybrid electrochemical energy storage system is believed to find a strong foothold in future advanced energy storage applications.

Analysis of the aging/stability process of organic solar cells based on PTB7:[70]PCBM and an alternative free-vacuum deposited cathode: the effect of active layer scaling

NASA Astrophysics Data System (ADS)

Barreiro-Argüelles, Denisse; Ramos-Ortiz, Gabriel; Maldonado, José-Luis L.; Romero-Borja, Daniel; Meneses-Nava, Marco-Antonio; Pérez-Gutiérrez, Enrique

2017-08-01

The PV performance and aging/stability of organic photovoltaic (OPV) devices based on the well-known system PTB7:[70]PCBM and an alternative air-stable electrode deposited at room conditions are fully studied when the active area is scaled by a factor of 25. On the other hand, the aging/stability processes were also studied through single diode model, impedance spectroscopy and light-beam induced current (LBIC) measurements in accordance with the established ISOS-D1 (dark storage) and ISOS-L1 (illumination conditions) protocols. Results are a good indication that the alternative cathode Field's metal (FM) cathode works as an encapsulating material and provides excellent PV performance comparable with the common and costly high-vacuum evaporated Al cathode.

Novel Shape-Stabilized Phase Change Materials Composed of Polyethylene Glycol/Nonsurfactant-Templated Mesoporous Silica: Preparation and Thermal Properties

NASA Astrophysics Data System (ADS)

Chen, Yan; Zhu, Yingying; Wang, Jinbao; Lv, Mengjiao; Zhang, Xiongjie; Gao, Junkai; Zhang, Zijun; Lei, Hao

2017-12-01

A novel shape-stabilized phase change material (PEG/TAMS), fabricated using tannic acid-templated mesoporous silica (TAMS) as a support for polyethylene glycol, was developed for thermal energy storage. The method used to synthesize TAMS was simple, cost effective, environmentally friendly, and free of surfactant. The characterization results indicated that PEG was physically absorbed to TAMS and that TAMS had no influence on the crystal structure of PEG. According to the TGA thermograms, PEG/TAMS has excellent thermal stability and can be applied over a wide temperature range. Additionally, the differential scanning calorimetry results suggested that PEG/TAMS has good thermal properties and that its fusion and solidification enthalpies reached 114.7 J/g and 102.4 J/g, respectively. The results indicated that PEG/TAMS has great potential for practical applications.

Liquid Salt as Green Solvent: A Novel Eco-Friendly Technique to Enhance Solubility and Stability of Poorly Soluble Drugs

NASA Astrophysics Data System (ADS)

Patel, Anant A.

As a result of tremendous efforts in past few decades, various techniques have been developed in order to resolve solubility issues associated with class II and IV drugs, However, majority of these techniques offer benefits associated with certain drawbacks; majorly including low drug loading, physical instability on storage and excessive use of environmentally challenging organic solvents. Hence, current effort was to develop an eco-friendly technique using liquid salt as green solvent, which can offer improvement in dissolution while maintaining long term stability. The liquid salt formulations (LSF) of poorly soluble model drugs ibuprofen, gemfibrozil and indomethacin were developed using 1-Ethyl-3-methylimidazolium ethyl sulfate (EMIM ES) as a non-toxic and environmentally friendly alternate to organic solvents. Liquid medications containing clear solutions of drug, EMIM ES and polysorbate 20, were adsorbed onto porous carrier Neusilin US2 to form free flowing powder. The LSF demonstrated greater rate and extent of dissolution compared to crystalline drugs. The dissolution data revealed that more than 80% drug release from LSF within 20 mins compared to less than 18% release from pure drugs. As high as 70% w/w liquid loading was achieved while maintaining good flowability and compressibility. In addition, the LSF samples exposed to high temperature and high humidity i.e. 40°C/80% RH for 8 weeks, demonstrated excellent physical stability without any signs of precipitation or crystallization. As most desirable form of administration is tablet, the developed liquid salt formulations were transformed into tablets using design of experiment approach by Design Expert Software. The tablet formulation composition and critical parameter were optimized using Box-Behnken Design. This innovative liquid salt formulation technique offered improvement in dissolution rate and extent as well as contributed to excellent physical stability on storage. Moreover, this formulation approach served as eco-friendly compelling alternate to conventional techniques involving organic solvents.

Novel jojoba oil-based emulsion gel formulations for clotrimazole delivery.

PubMed

Shahin, Mostafa; Hady, Seham Abdel; Hammad, Mohammed; Mortada, Nahed

2011-03-01

Jojoba oil-based emulgel formulations were prepared using different concentrations of various gelling agents, such as hydroxypropyl methylcellulose (HPMC) and Carbopol 934 P and combination of both. The prepared emulgels were physically evaluated for their stability after temperature cycle test, centrifugation and long-term shelf storage for 1 year at room temperature. The in vitro release at 37 °C was studied to define the effect of the concentration and type of the gelling agent. A comparison between the formulated emulgels and two commercially available products, Candistan® and Canesten® creams, was carried out to judge their efficacy and stability. The prepared emulgels exhibited non-Newtonian shear thinning behavior with little or no thixotropy. Four emulgels showed excellent stability as they demonstrated consistent rheological model under different treatment conditions. The in vitro release test showed variation in the extent of percent drug released. The drug release from the commercial preparation was lower than some of the prepared emulgel formulae. One formula containing combination of the two gelling agents (HPMC and Carbopol 934 P), showed excellent stability and high extent of clotrimazole release was microbiologically evaluated against Candida albicans using cylinder and plate method. The selected formula showed superior antimycotic activity compared to the commercially available formulation. Further in vivo animal studies for the obtained stable formula is recommended. © 2011 American Association of Pharmaceutical Scientists

2D Perovskites with Short Interlayer Distance for High-Performance Solar Cell Application.

PubMed

Ma, Chunqing; Shen, Dong; Ng, Tsz-Wai; Lo, Ming-Fai; Lee, Chun-Sing

2018-05-01

2D perovskites have emerged as one of the most promising photovoltaic materials owing to their excellent stability compared with their 3D counterparts. However, in typical 2D perovskites, the highly conductive inorganic layers are isolated by large organic cations leading to quantum confinement and thus inferior electrical conductivity across layers. To address this issue, the large organic cations are replaced with small propane-1,3-diammonium (PDA) cations to reduce distance between the inorganic perovskite layers. As shown by optical characterizations, quantum confinement is no longer dominating in the PDA-based 2D perovskites. This leads to considerable enhancement of charge transport as confirmed with electrochemical impedance spectroscopy, time-resolved photoluminescence, and mobility measurements. The improved electric properties of the interlayer-engineered 2D perovskites yield a power conversion efficiency of 13.0%. Furthermore, environmental stabilities of the PDA-based 2D perovskites are improved. PDA-based 2D perovskite solar cells (PSCs) with encapsulation can retain over 90% of their efficiency upon storage for over 1000 h, and PSCs without encapsulation can maintain their initial efficiency at 70 °C for over 100 h, which exhibit promising stabilities. These results reveal excellent optoelectronic properties and intrinsic stabilities of the layered perovskites with reduced interlayer distance. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of metal ion intercalation on the structure of MXene and water dynamics on its internal surfaces

DOE PAGES

Osti, Naresh C.; Naguib, Michael; Ostadhossein, Alireza; ...

2016-03-24

MXenes are a recently discovered class of 2D materials with an excellent potential for energy storage applications. Because MXene surfaces are hydrophilic and attractive interaction forces between the layers are relatively weak, water molecules can spontaneously intercalate at ambient humidity and significantly influence the key properties of this 2D material. Using complementary X-ray and neutron scattering techniques, we demonstrate that intercalation with potassium cations significantly improves structural homogeneity and water stability in MXenes. Furthermore, in agreement with molecular dynamics simulations, intercalated potassium ions reduce the water self-diffusion coefficient by 2 orders of magnitude, suggesting greater stability of hydrated MXene againstmore » changing environmental conditions.« less

Development and Provision of Functional Foods to Promote Health on Long-Duration Space Missions

NASA Technical Reports Server (NTRS)

Bermudez-Aguirre, D.; Cooper, M. R.; Douglas, G.; Smith, S.

2016-01-01

During long-duration NASA space missions, such as proposed missions to Mars, astronauts may experience negative physiological effects such as bone loss. Functional foods such as high-lycopene, high-flavonoids and high-omega-3 products and fruits and vegetables may mitigate the negative effects of spaceflight on physiological factors including the bone health of crewmembers. Previous studies showed that current ISS provisions provide high-lycopene and high-omega-3 food items but the variety is limited, which could promote menu fatigue. Bioactive compounds can degrade like other chemical compounds and lose functionality. The native concentrations and stability of bioactive compounds have never been determined in spaceflight foods, and adequate information is not available for commercial products for the storage durations required for space exploration (5 years). The purpose of this task is to develop new spaceflight foods that are high in omega-3 fatty acids, lycopene, or flavonoids, identify commercial products with these bioactive compounds that meet spaceflight requirements, and define the stability of these nutrients in storage to enable purposeful functional food incorporation into the space food system. The impact of storage temperature on the stability of lutein, lycopene, beta-carotene, omega-3 fatty acids, phenolics, anthocyanins and sterols is being studied in 12 ISS menu items stored at three different temperatures (4, 21, 35 degree C) over 2 years. Additionally, nutrient and quality stability are being assessed on a larger food set stored at 21 degree C over 2 years that contains twelve newly developed foods, 10 commercial products repackaged to spaceflight requirements, and another 5 current ISS menu items expected to be good sources of omega-3 fatty acids, lycopene, or flavonoids. All items were shipped overnight to the Linus Pauling Institute at Oregon State University (Corvalis, OR) after processing and 1-year of storage and analyzed for bioactive compound concentrations. Sensory evaluation was conducted on the newly developed functional foods and commercial products with untrained panelists (n is greater than or equal to 25) using a 9-point Hedonic scale to test sensory attributes and overall acceptability after processing and 1-year of storage (21 degree C). Repeat nutritional and sensory analyses will be conducted in the same foods after the 2-year storage period is completed. The stability of bioactive compounds in the selected foods was dependent on storage temperature and food matrix. Omega-3 showed excellent stability in the analyzed products after 1-year of storage, regardless of the storage temperature; phenolic compounds also showed good stability. Lycopene was more stable in oil-based products rather than water-based products because of the protection that lipids offer to lycopene molecules. Also, lycopene was more stable in freeze-dried products than in high moisture foods. The 12 newly developed functional foods showed good overall acceptability in sensory attributes after processing (average score 7.2 out of 9.0) and maintained sensory quality through 1-year (21 degree C); the overall acceptability was on average 7.1 after storage. Similar behavior was observed for the 10 commercial products after 1 year. The developed products are good sources of omega-3 (both plant and marine), vegetables (7 vegetable-based products), and good sources of carotenoids, such as the Curry Pumpkin Soup and the Sweet and Savory Kale. Nine of the new products, such as Mango Salad, Pickled Beets, and Braised Red Cabbage, are rich in phenolic compounds. Stability of most of the studied nutrients seems to be adequate after 1-year of storage in most of the tested foods. However, storage temperature of the food must be considered during long-duration space missions to achieve stability of all nutrients. Likewise, more information is needed regarding nutrient retention after 2-years of storage to identify nutritional gaps that may be expected over the 5-year shelf life required for a Mars mission. New developed products will be filling a gap in the current space food system to minimize menu fatigue, provide specific nutrients to reduce the negative effects of long-duration space missions and maintain crew members' health. Information about bioactive compounds in developed products after 1-year and 2-year of storage will provide the knowledge base for further product development.

pH-regulative synthesis of Na 3(VPO 4) 2F 3 nanoflowers and their improved Na cycling stability

DOE PAGES

Qi, Yuruo; Mu, Linqin; Zhao, Junmei; ...

2016-04-08

Na-ion batteries are becoming increasingly attractive as a low cost energy storage device. Sodium vanadium fluorophosphates have been studied extensively recently due to their high storage capacity and high discharge voltage. Shape and size often have a crucial influence over the properties. The controlling synthesis of nanoparticles with special microstructures is significant, which becomes a challenging issue and has drawn considerable attention. In this study, Na 3(VPO 4) 2F 3 nanoflowers have been synthesized via a pH-regulative low-temperature (120 °C) hydro-thermal route. In particular, it is a green route without any organic compounds involved. The hydro-thermal reaction time for themore » formation of Na 3(VPO 4) 2F 3 nanoflowers has also been investigated. A weak acid environment (pH = 2.60) with the possible presence of hydrogen fluoride molecules is necessary for the formation of the desired nanoflower microstructures. Moreover, compared to the nanoparticles obtained by Na 2HPO 4·12H 2O, the as-synthesized Na 3(VPO 4) 2F 3 nanoflowers showed an excellent Na-storage performance in terms of superior cycle stability, even without any further carbon coating or high-temperature treatment.« less

Vitamin D2 Stability During the Refrigerated Storage of Ultraviolet B-Treated Cultivated Culinary-Medicinal Mushrooms.

PubMed

Slawinska, Aneta; Fornal, Emilia; Radzki, Wojciech; Jablonska-Rys, Ewa; Parfieniuk, Ewa

2017-01-01

The effects of ultraviolet B (UVB) irradiation on the synthesis of vitamin D2 and its stability during refrigerated storage was determined in fresh cultivated culinary-medicinal mushrooms (Agaricus bisporus, Pleurotus ostreatus, and Lentinus edodes) after harvest. The irradiated mushrooms were stored at 4°C for up to 10 days. The concentrations of vitamin D2 and ergosterol were determined using ultrahigh-performance liquid chromatography/tandem mass spectrometry. The cultivated mushrooms not treated with UVB were devoid of vitamin D2. After UVB irradiation, we obtained mushrooms with a large amount of ergocalciferol. A. bisporus showed the lowest vitamin D2 content (3.55 ± 0.11 μg D2/g dry weight); P. ostreatus contained 58.96 ± 1.15 μg D2/g dry weight, and L. edodes contained 29.46 ± 2.21 μg/g dry weight. During storage at 4°C, the amount of vitamin D2 was gradually decreased in P. ostreatus and L. edodes, whereas in A. bisporus vitamin D2 gradually increased until the sixth day, then decreased. Mushrooms exposed to UVB radiation contain a significant amount of vitamin D2 and are therefore an excellent food source of vitamin D.

Development of a dry, stable and inhalable acyl-homoserine-lactone-acylase powder formulation for the treatment of pulmonary Pseudomonas aeruginosa infections.

PubMed

Wahjudi, Mariana; Murugappan, Senthil; van Merkerk, Ronald; Eissens, Anko C; Visser, Marinella R; Hinrichs, Wouter L J; Quax, Wim J

2013-03-12

In the lungs of cystic fibrosis (CF) patients, Pseudomonas aeruginosa commonly causes chronic infections. It has been shown that the P. aeruginosa quorum sensing (QS) system controls the expression of virulence factors during invasion and infection to host cells. PvdQ is an acyl-homoserine lactone (AHL) acylase able to degrade the signal molecule of P. aeruginosa QS. The role of PvdQ in inhibiting the QS and its successive virulence determinants has been established in in vitro as well as in in vivo, the latter in a Caenorabdhitis elegans model. For the treatment of pulmonary P. aeruginosa infections, we propose that PvdQ can be best administered directly to the lungs of the patients as a dry powder because this is expected to give specific advantages in delivery as compared to nebulizing. Therefore in this study we investigated the production of a PvdQ powder by spray-freeze drying using mannitol, trehalose and inulin as excipient. The activity of PvdQ in the powder was determined immediately after production and after subsequent storage during 4 weeks at 20°C and 55°C. We found that the enzymatic activity of PvdQ is fully maintained during spray-freeze drying using mannitol, trehalose or inulin as excipient. However, mannitol was not able to stabilize the protein during storage, while PvdQ incorporated in trehalose or inulin was fully stabilized even during storage at 55°C for at least 4 weeks. The poor stabilizing capacities of mannitol during storage could be related to its crystalline nature while the excellent stabilizing capacities of trehalose and inulin during storage could be related to their amorphous nature. The trehalose and inulin-based particles consisted of porous spheres with a volume average aerodynamical diameter of ∼1.8 μm implying that they are suitable for pulmonary delivery. This is the first study in which an AHL-degrading enzyme is processed into spray-freeze-dried powder suitable for inhalation. Copyright © 2013 Elsevier B.V. All rights reserved.

Filter paper saturated by urine sample in metabolic disorders detection by proton magnetic resonance spectroscopy.

PubMed

Blasco, Hélène; Garrigue, Marie-Ange; De Vos, Aymeric; Antar, Catherine; Labarthe, François; Maillot, François; Andres, Christian R; Nadal-Desbarats, Lydie

2010-02-01

NMR spectroscopy of urine samples is able to diagnose many inborn errors of metabolism (IEM). However, urinary metabolites have a poor stability, requiring special care for routine analysis (storage of urine at -20 or -80 degrees C, fast transport). The aim of our study was to investigate the reliability of dried urine filter paper for urine storage and transport and to evaluate the ability of NMR to detect several IEM using this method. Urine samples from five healthy subjects were analyzed by (1)H NMR following different storage conditions (-20 vs 4 degrees C vs dried on filter paper) and at different time points (24 h, 48 h, 96 h, and 7 days). Urine pattern of fresh urine was considered as a reference. We analyzed the conservation of some amino acids and organic acids using Bland and Altman plot with intraclass correlation coefficient determination. Then, we evaluated the use of filter paper to detect four different IEM (methylmalonic and isovaleric acidurias, ornithine transcarbamylase deficiency, and cystinuria). Analysis of urine samples from healthy subjects revealed a high stability of studied molecules (ICC > 0.8) even after 7 days of storage on filter paper. Moreover, an excellent preservation of metabolites specifically accumulated in IEM was observed when analysis of dried urine filter paper was compared to fresh urine (coefficient of variation < 15%). This preliminary study demonstrates that storage of dried urine on filter paper is reliable for (1)H NMR spectroscopy analysis. Preservation of urine molecules over time using that method is convenient for routine clinical practice.

Hybrid Graphene-Polyoxometalates Nanofluids as Liquid Electrodes for Dual Energy Storage in Novel Flow Cells.

PubMed

Dubal, Deepak P; Rueda-Garcia, Daniel; Marchante, Carlos; Benages, Raul; Gomez-Romero, Pedro

2018-02-22

Solid Hybrid materials abound. But flowing versions of them are new actors in the materials science landscape and in particular for energy applications. This paper presents a new way to deliver nanostructured hybrid materials for energy storage, namely, in the form of nanofluids. We present here the first example of a hybrid electroactive nanofluid (HENFs) combining capacitive and faradaic energy storage mechanisms in a single fluid material. This liquid electrode is composed of reduced graphene oxide and polyoxometalates (rGO-POMs) forming a stable nanocomposite for electrochemical energy storage in novel Nanofluid Flow Cells. Two graphene based hybrid materials (rGO-phosphomolybdate, rGO-PMo 12 and rGO-phosphotungstate, rGO-PW 12 ) were synthesized and dispersed with the aid of a surfactant in 1 M H 2 SO 4 aqueous electrolyte to yield highly stable hybrid electroactive nanofluids (HENFs) of low viscosity which were tested in a home-made flow cell under static and continuous flowing conditions. Remarkably, even low concentration rGO-POMs HENFs (0.025 wt%) exhibited high specific capacitances of 273 F/g(rGO-PW 12 ) and 305 F/g(rGO-PMo 12 ) with high specific energy and specific power. Moreover, rGO-POM HENFs show excellent cycling stability (∼95 %) as well as Coulombic efficiency (∼77-79 %) after 2000 cycles. Thus, rGO-POM HENFs effectively behave as real liquid electrodes with excellent properties, demonstrating the possible future application of HENFs for dual energy storage in a new generation of Nanofluid Flow Cells. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flexible solid-state supercapacitors based on three-dimensional graphene hydrogel films.

PubMed

Xu, Yuxi; Lin, Zhaoyang; Huang, Xiaoqing; Liu, Yuan; Huang, Yu; Duan, Xiangfeng

2013-05-28

Flexible solid-state supercapacitors are of considerable interest as mobile power supply for future flexible electronics. Graphene or carbon nanotubes based thin films have been used to fabricate flexible solid-state supercapacitors with high gravimetric specific capacitances (80-200 F/g), but usually with a rather low overall or areal specific capacitance (3-50 mF/cm(2)) due to the ultrasmall electrode thickness (typically a few micrometers) and ultralow mass loading, which is not desirable for practical applications. Here we report the exploration of a three-dimensional (3D) graphene hydrogel for the fabrication of high-performance solid-state flexible supercapacitors. With a highly interconnected 3D network structure, graphene hydrogel exhibits exceptional electrical conductivity and mechanical robustness to make it an excellent material for flexible energy storage devices. Our studies demonstrate that flexible supercapacitors with a 120 μm thick graphene hydrogel thin film can exhibit excellent capacitive characteristics, including a high gravimetric specific capacitance of 186 F/g (up to 196 F/g for a 42 μm thick electrode), an unprecedented areal specific capacitance of 372 mF/cm(2) (up to 402 mF/cm(2) for a 185 μm thick electrode), low leakage current (10.6 μA), excellent cycling stability, and extraordinary mechanical flexibility. This study demonstrates the exciting potential of 3D graphene macrostructures for high-performance flexible energy storage devices.

Hydrogen storage in lithium hydride: A theoretical approach

NASA Astrophysics Data System (ADS)

Banger, Suman; Nayak, Vikas; Verma, U. P.

2018-04-01

First principles calculations have been carried out to analyze structural stability of lithium hydride (LiH) in NaCl phase using the full potential linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory (DFT). Calculations have been extended to physiosorbed H-atom compounds LiH·H2, LiH·3H2 and LiH·4H2. The obtained results are discussed in the paper. The results for LiH are in excellent agreement with earlier reported data. The obtained direct energy band gap of LiH is 3.0 eV which is in excellent agreement with earlier reported theoretical band gap. The electronic band structure plots of the hydrogen adsorbed compounds show metallic behavior. The elastic constants, anisotropy factor, shear modulus, Young's modulus, Poisson's ratio and cohesive energies of all the compounds are calculated. Calculation of the optical spectra such as the real and imaginary parts of dielectric function, optical reflectivity, absorption coefficient, optical conductivity, refractive index, extinction coefficient and electron energy loss are performed for the energy range 0-15 eV. The obtained results for LiH·H2, LiH·3H2 and LiH·4H2, are reported for the first time. This study has been made in search of materials for hydrogen storage. It is concluded that LiH is a promising material for hydrogen storage.

Robust and conductive two-dimensional metal-organic frameworks with exceptionally high volumetric and areal capacitance

DOE PAGES

Feng, Dawei; Lei, Ting; Lukatskaya, Maria R.; ...

2018-01-01

For miniaturized capacitive energy storage, volumetric and areal capacitances are more important metrics than gravimetric ones because of the constraints imposed by device volume and chip area. Typically used in commercial supercapacitors, porous carbons, although they provide a stable and reliable performance, lack volumetric performance because of their inherently low density and moderate capacitances. In this paper, we report a high-performing electrode based on conductive hexaaminobenzene (HAB)-derived two-dimensional metal-organic frameworks (MOFs). In addition to possessing a high packing density and hierarchical porous structure, these MOFs also exhibit excellent chemical stability in both acidic and basic aqueous solutions, which is inmore » sharp contrast to conventional MOFs. Submillimetre-thick pellets of HAB MOFs showed high volumetric capacitances up to 760 F cm -3 and high areal capacitances over 20 F cm -2. Furthermore, the HAB MOF electrodes exhibited highly reversible redox behaviours and good cycling stability with a capacitance retention of 90% after 12,000 cycles. In conclusion, these promising results demonstrate the potential of using redox-active conductive MOFs in energy-storage applications.« less

Phase restructuring in transition metal dichalcogenides for highly stable energy storage

DOE PAGES

Leng, Kai; Chen, Zhongxin; Zhao, Xiaoxu; ...

2016-09-16

Achieving homogeneous phase transition and uniform charge distribution is essential for good cycle stability and high capacity when phase conversion materials are used as electrodes. Herein, we show that chemical lithiation of bulk 2H-MoS 2 distorts its crystalline domains in three primary directions to produce mosaic-like 1T' nanocrystalline domains, which improve phase and charge uniformity during subsequent electrochemical phase conversion. 1T'-Li xMoS 2, a macroscopic dense material with interconnected nanoscale grains, shows excellent cycle stability and rate capability in a lithium rechargeable battery compared to bulk or exfoliated-restacked MoS 2. Transmission electron microscopy studies reveal that the interconnected MoS 2more » nanocrystals created during the phase change process are reformable even after multiple cycles of galvanostatic charging/discharging, which allows them to play important roles in the long term cycling performance of the chemically intercalated TMD materials. Finally, these studies shed light on how bulk TMDs can be processed into quasi-2D nanophase material for stable energy storage.« less

Robust and conductive two-dimensional metal-organic frameworks with exceptionally high volumetric and areal capacitance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Dawei; Lei, Ting; Lukatskaya, Maria R.

For miniaturized capacitive energy storage, volumetric and areal capacitances are more important metrics than gravimetric ones because of the constraints imposed by device volume and chip area. Typically used in commercial supercapacitors, porous carbons, although they provide a stable and reliable performance, lack volumetric performance because of their inherently low density and moderate capacitances. In this paper, we report a high-performing electrode based on conductive hexaaminobenzene (HAB)-derived two-dimensional metal-organic frameworks (MOFs). In addition to possessing a high packing density and hierarchical porous structure, these MOFs also exhibit excellent chemical stability in both acidic and basic aqueous solutions, which is inmore » sharp contrast to conventional MOFs. Submillimetre-thick pellets of HAB MOFs showed high volumetric capacitances up to 760 F cm -3 and high areal capacitances over 20 F cm -2. Furthermore, the HAB MOF electrodes exhibited highly reversible redox behaviours and good cycling stability with a capacitance retention of 90% after 12,000 cycles. In conclusion, these promising results demonstrate the potential of using redox-active conductive MOFs in energy-storage applications.« less

Long-life Li/polysulphide batteries with high sulphur loading enabled by lightweight three-dimensional nitrogen/sulphur-codoped graphene sponge

PubMed Central

Zhou, Guangmin; Paek, Eunsu; Hwang, Gyeong S.; Manthiram, Arumugam

2015-01-01

Lithium–sulphur batteries with a high theoretical energy density are regarded as promising energy storage devices for electric vehicles and large-scale electricity storage. However, the low active material utilization, low sulphur loading and poor cycling stability restrict their practical applications. Herein, we present an effective strategy to obtain Li/polysulphide batteries with high-energy density and long-cyclic life using three-dimensional nitrogen/sulphur codoped graphene sponge electrodes. The nitrogen/sulphur codoped graphene sponge electrode provides enough space for a high sulphur loading, facilitates fast charge transfer and better immobilization of polysulphide ions. The hetero-doped nitrogen/sulphur sites are demonstrated to show strong binding energy and be capable of anchoring polysulphides based on first-principles calculations. As a result, a high specific capacity of 1,200 mAh g−1 at 0.2C rate, a high-rate capacity of 430 mAh g−1 at 2C rate and excellent cycling stability for 500 cycles with ∼0.078% capacity decay per cycle are achieved. PMID:26182892

Synergetic Effect of Yolk-Shell Structure and Uniform Mixing of SnS-MoS₂ Nanocrystals for Improved Na-Ion Storage Capabilities.

PubMed

Choi, Seung Ho; Kang, Yun Chan

2015-11-11

Mixed metal sulfide composite microspheres with a yolk-shell structure for sodium-ion batteries are studied. Tin-molybdenum oxide yolk-shell microspheres prepared by a one-pot spray pyrolysis process transform into yolk-shell SnS-MoS2 composite microspheres. The discharge capacities of the yolk-shell and dense-structured SnS-MoS2 composite microspheres for the 100th cycle are 396 and 207 mA h g(-1), and their capacity retentions measured from the second cycle are 89 and 47%, respectively. The yolk-shell SnS-MoS2 composite microspheres with high structural stability during repeated sodium insertion and desertion processes have low charge-transfer resistance even after long-term cycling. The synergetic effect of the yolk-shell structure and uniform mixing of the SnS and MoS2 nanocrystals result in the excellent sodium-ion storage properties of the yolk-shell SnS-MoS2 composite microspheres by improving their structural stability during cycling.

Robust and conductive two-dimensional metal-organic frameworks with exceptionally high volumetric and areal capacitance

NASA Astrophysics Data System (ADS)

Feng, Dawei; Lei, Ting; Lukatskaya, Maria R.; Park, Jihye; Huang, Zhehao; Lee, Minah; Shaw, Leo; Chen, Shucheng; Yakovenko, Andrey A.; Kulkarni, Ambarish; Xiao, Jianping; Fredrickson, Kurt; Tok, Jeffrey B.; Zou, Xiaodong; Cui, Yi; Bao, Zhenan

2018-01-01

For miniaturized capacitive energy storage, volumetric and areal capacitances are more important metrics than gravimetric ones because of the constraints imposed by device volume and chip area. Typically used in commercial supercapacitors, porous carbons, although they provide a stable and reliable performance, lack volumetric performance because of their inherently low density and moderate capacitances. Here we report a high-performing electrode based on conductive hexaaminobenzene (HAB)-derived two-dimensional metal-organic frameworks (MOFs). In addition to possessing a high packing density and hierarchical porous structure, these MOFs also exhibit excellent chemical stability in both acidic and basic aqueous solutions, which is in sharp contrast to conventional MOFs. Submillimetre-thick pellets of HAB MOFs showed high volumetric capacitances up to 760 F cm-3 and high areal capacitances over 20 F cm-2. Furthermore, the HAB MOF electrodes exhibited highly reversible redox behaviours and good cycling stability with a capacitance retention of 90% after 12,000 cycles. These promising results demonstrate the potential of using redox-active conductive MOFs in energy-storage applications.

Porous Ni-Co-Mn oxides prisms for high performance electrochemical energy storage

NASA Astrophysics Data System (ADS)

Zhao, Jianbo; Li, Man; Li, Junru; Wei, Chengzhen; He, Yuyue; Huang, Yixuan; Li, Qiaoling

2017-12-01

Porous Ni-Co-Mn oxides prisms have been successfully synthesized via a facile route. The process involves the preparation of nickel-cobalt-manganese acetate hydroxide by a simple co-precipitation method and subsequently the thermal treatment. The as-synthesized Ni-Co-Mn oxides prisms had a large surface area (96.53 m2 g-1) and porous structure. As electrode materials for supercapacitors, porous Ni-Co-Mn oxides prisms showed a high specific capacitance of 1623.5 F g-1 at 1.0 A g-1. Moreover, the porous Ni-Co-Mn oxides prisms were also employed as positive electrode materials to assemble flexible solid-state asymmetric supercapacitors. The resulting flexible device had a maximum volumetric energy density (0.885 mW h cm-3) and power density (48.9 mW cm-3). Encouragingly, the flexible device exhibited good cycling stability with only about 2.2% loss after 5000 charge-discharge cycles and excellent mechanical stability. These results indicate that porous Ni-Co-Mn oxides prisms have the promising application in high performance electrochemical energy storage.

Robust Design of a Particle-Free Silver-Organo-Complex Ink with High Conductivity and Inkjet Stability for Flexible Electronics.

PubMed

Vaseem, Mohammad; McKerricher, Garret; Shamim, Atif

2016-01-13

Currently, silver-nanoparticle-based inkjet ink is commercially available. This type of ink has several serious problems such as a complex synthesis protocol, high cost, high sintering temperatures (∼200 °C), particle aggregation, nozzle clogging, poor shelf life, and jetting instability. For the emerging field of printed electronics, these shortcomings in conductive inks are barriers for their widespread use in practical applications. Formulating particle-free silver inks has potential to solve these issues and requires careful design of the silver complexation. The ink complex must meet various requirements, such as in situ reduction, optimum viscosity, storage and jetting stability, smooth uniform sintered films, excellent adhesion, and high conductivity. This study presents a robust formulation of silver-organo-complex (SOC) ink, where complexing molecules act as reducing agents. The 17 wt % silver loaded ink was printed and sintered on a wide range of substrates with uniform surface morphology and excellent adhesion. The jetting stability was monitored for 5 months to confirm that the ink was robust and highly stable with consistent jetting performance. Radio frequency inductors, which are highly sensitive to metal quality, were demonstrated as a proof of concept on flexible PEN substrate. This is a major step toward producing high-quality electronic components with a robust inkjet printing process.

Development of a Highly Stable, Nonaqueous Glucagon Formulation for Delivery via Infusion Pump Systems

PubMed Central

Newswanger, Brett; Ammons, Steve; Phadnis, Neelima; Ward, W. Kenneth; Castle, Jessica; Campbell, Robert W.

2015-01-01

Background: Despite a vigorous research effort, to date, the development of systems that achieve glucagon stability in aqueous formulations (without reconstitution) has failed to produce any clinical candidates. We have developed a novel, nonaqueous glucagon formulation based on a biocompatible pharmaceutical solvent, dimethyl sulfoxide, which demonstrates excellent physical and chemical stability at relatively high concentrations and at high temperatures. Methods: This article reports the development of a novel, biocompatible, nonaqueous native human glucagon formulation for potential use in subcutaneous infusion pump systems. Results: Data are presented that demonstrate physical and chemical stability under presumed storage conditions (>2 years at room temperature) as well as “in use” stability and compatibility in an Insulet’s OmniPod® infusion pump. Also presented are results of a skin irritation study in a rabbit model and pharmacokinetics/pharmacodynamics data following pump administration of glucagon in a diabetic swine model. Conclusions: This nonaqueous glucagon formulation is suitable for further clinical development in pump systems. PMID:25550410

Development of a highly stable, nonaqueous glucagon formulation for delivery via infusion pump systems.

PubMed

Newswanger, Brett; Ammons, Steve; Phadnis, Neelima; Ward, W Kenneth; Castle, Jessica; Campbell, Robert W; Prestrelski, Steven J

2015-01-01

Despite a vigorous research effort, to date, the development of systems that achieve glucagon stability in aqueous formulations (without reconstitution) has failed to produce any clinical candidates. We have developed a novel, nonaqueous glucagon formulation based on a biocompatible pharmaceutical solvent, dimethyl sulfoxide, which demonstrates excellent physical and chemical stability at relatively high concentrations and at high temperatures. This article reports the development of a novel, biocompatible, nonaqueous native human glucagon formulation for potential use in subcutaneous infusion pump systems. Data are presented that demonstrate physical and chemical stability under presumed storage conditions (>2 years at room temperature) as well as "in use" stability and compatibility in an Insulet's OmniPod(®) infusion pump. Also presented are results of a skin irritation study in a rabbit model and pharmacokinetics/pharmacodynamics data following pump administration of glucagon in a diabetic swine model. This nonaqueous glucagon formulation is suitable for further clinical development in pump systems. © 2015 Diabetes Technology Society.

Heterogeneous nanocrystals assembled TiO2/SnO2/C composite for improved lithium storage

NASA Astrophysics Data System (ADS)

Tian, Qinghua; Mao, Yuning; Zhang, Xuzhen; Yang, Li

2018-07-01

Using stable TiO2 and flexible carbon as double-functional structure protector of nanostructural SnO2 to fabricate TiO2/SnO2/C composites is widely considered as a favorable strategy for improving the lithium storage performance of SnO2 anodes. But, it is still a challenge to obtain a satisfying TiO2/SnO2/C composite. Herein, an interesting porous nanostructure of TiO2/SnO2/C nanosphere composite assembled by TiO2 and SnO2 nanocrystals with an outer carbon coating has been fabricated by a well-designed approach. Thanks to the perfectly combined action of porous spherical nanostructure, TiO2 and SnO2 nanocrystals and carbon coating, the as-prepared composite obtains excellent structure stability and improved electrochemcial properties. When used as a promising anode for lithium-ion batteres, it exhibits outstanding lithium storage performance, delivering a high capacity of 687.2 mAh g-1 after even 400 cycles.

Ascorbic Acid-Assisted Eco-friendly Synthesis of NiCo2O4 Nanoparticles as an Anode Material for High-Performance Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Karunakaran, Gopalu; Maduraiveeran, Govindhan; Kolesnikov, Evgeny; Balasingam, Suresh Kannan; Viktorovich, Lysov Dmitry; Ilinyh, Igor; Gorshenkov, Mikhail V.; Sasidharan, Manickam; Kuznetsov, Denis; Kundu, Manab

2018-05-01

We have synthesized NiCo2O4 nanoparticles (NCO NPs) using an ascorbic acid-assisted co-precipitation method for the first time. When NCO NPs are used as an anode material for lithium-ion batteries, the cell exhibits superior lithium storage properties, such as high capacity (700 mA h g-1 after 300 cycles at 200 mA g-1), excellent rate capabilities (applied current density range 100-1200 mA g-1), and impressive cycling stability (at 1200 mA g-1 up to 650 cycles). The enhanced electrochemical properties of NCO NPs are due to the nanometer dimensions which not only offers a smooth charge-transport pathway and short diffusion paths of the lithium ions but also adequate spaces for volume expansion during Li storage. Hence, this eco-friendly synthesis approach will provide a new strategy for the synthesis of various nanostructured metal oxide compounds, for energy conversion and storage systems applications.

Large-Scale Multifunctional Electrochromic-Energy Storage Device Based on Tungsten Trioxide Monohydrate Nanosheets and Prussian White.

PubMed

Bi, Zhijie; Li, Xiaomin; Chen, Yongbo; He, Xiaoli; Xu, Xiaoke; Gao, Xiangdong

2017-09-06

A high-performance electrochromic-energy storage device (EESD) is developed, which successfully realizes the multifunctional combination of electrochromism and energy storage by constructing tungsten trioxide monohydrate (WO 3 ·H 2 O) nanosheets and Prussian white (PW) film as asymmetric electrodes. The EESD presents excellent electrochromic properties of broad optical modulation (61.7%), ultrafast response speed (1.84/1.95 s), and great coloration efficiency (139.4 cm 2 C -1 ). In particular, remarkable cyclic stability (sustaining 82.5% of its initial optical modulation after 2500 cycles as an electrochromic device, almost fully maintaining its capacitance after 1000 cycles as an energy storage device) is achieved. The EESD is also able to visually detect the energy storage level via reversible and fast color changes. Moreover, the EESD can be combined with commercial solar cells to constitute an intelligent operating system in the architectures, which would realize the adjustment of indoor sunlight and the improvement of physical comfort totally by the rational utilization of solar energy without additional electricity. Besides, a scaled-up EESD (10 × 11 cm 2 ) is further fabricated as a prototype. Such promising EESD shows huge potential in practically serving as electrochromic smart windows and energy storage devices.

Rod-like polyaniline supported on three-dimensional boron and nitrogen-co-doped graphene frameworks for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Liao, Kexuan; Gao, Jialu; Fan, Jinchen; Mo, Yao; Xu, Qunjie; Min, Yulin

2017-12-01

In this work, novel three-dimensional (3D) boron and nitrogen-co-doped three-dimensional (3D) graphene frameworks (BN-GFs) supporting rod-like polyaniline (PANI) are facilely prepared and used as electrodes for high-performance supercapacitors. The results demonstrated that BN-GFs with tuned electronic structure can not only provide a large surface area for rod-like PANI to anchor but also effectively facilitate the ion transfer and charge storage in the electrode. The PANI/BN-GF composite with wrinkled boron and nitrogen-co-doped graphene sheets interconnected by rod-like PANI exhibits excellent capacitive properties with a maximum specific capacitance of 596 F/g at a current density of 0.5 A/g. Notably, they also show excellent cycling stability with more than 81% capacitance retention after 5000 charge-discharge cycles.

Freestanding polyaniline nanorods grown on graphene for highly capacitive energy storage

NASA Astrophysics Data System (ADS)

Li, Zijiong; Qin, Zhen; Yang, Baocheng; Guo, Jian; Wang, Haiyan; Zhang, Weiyang; Lv, Xiaowei; Stack, Alison

2015-02-01

Freestanding polyaniline (PANI) nanorods grown in situ on microwave-expanded graphene oxide (MEGO) sheets were prepared through a facile solution method. The morphological characterization indicates that large quantity of free-standing PANI nanorods with average diameter of 50 nm were uniformly deposited onto the double sides of the MEGO nanosheets to form a sandwich structure. The hybrid of PANI/MEGO (GPANI) exhibit high specific surface area and high electrical conductivity, compared with pristine PANI nanorods. When evaluated as electrodes for supercapacitors, the GPANI demonstrate high specific capacitance of 628 F g-1 at a current density of 1.1 A g-1, high-rate performance, and excellent cycle stability compared to individual component. Such excellent electrochemical performance should be attributed to the combined double-layer capacitance and pseudo -capacitance mechanisms from the MEGO sheets and PANI nanorods.

Identification of catalytic sites for oxygen reduction and oxygen evolution in N-doped graphene materials: Development of highly efficient metal-free bifunctional electrocatalyst

PubMed Central

Yang, Hong Bin; Miao, Jianwei; Hung, Sung-Fu; Chen, Jiazang; Tao, Hua Bing; Wang, Xizu; Zhang, Liping; Chen, Rong; Gao, Jiajian; Chen, Hao Ming; Dai, Liming; Liu, Bin

2016-01-01

Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are critical to renewable energy conversion and storage technologies. Heteroatom-doped carbon nanomaterials have been reported to be efficient metal-free electrocatalysts for ORR in fuel cells for energy conversion, as well as ORR and OER in metal-air batteries for energy storage. We reported that metal-free three-dimensional (3D) graphene nanoribbon networks (N-GRW) doped with nitrogen exhibited superb bifunctional electrocatalytic activities for both ORR and OER, with an excellent stability in alkaline electrolytes (for example, KOH). For the first time, it was experimentally demonstrated that the electron-donating quaternary N sites were responsible for ORR, whereas the electron-withdrawing pyridinic N moieties in N-GRW served as active sites for OER. The unique 3D nanoarchitecture provided a high density of the ORR and OER active sites and facilitated the electrolyte and electron transports. As a result, the as-prepared N-GRW holds great potential as a low-cost, highly efficient air cathode in rechargeable metal-air batteries. Rechargeable zinc-air batteries with the N-GRW air electrode in a two-electrode configuration exhibited an open-circuit voltage of 1.46 V, a specific capacity of 873 mAh g−1, and a peak power density of 65 mW cm−2, which could be continuously charged and discharged with an excellent cycling stability. Our work should open up new avenues for the development of various carbon-based metal-free bifunctional electrocatalysts of practical significance. PMID:27152333

Hierarchically interconnected porous scaffolds for phase change materials with improved thermal conductivity and efficient solar-to-electric energy conversion.

PubMed

Yang, Jie; Yu, Peng; Tang, Li-Sheng; Bao, Rui-Ying; Liu, Zheng-Ying; Yang, Ming-Bo; Yang, Wei

2017-11-23

An ice-templating self-assembly strategy and a vacuum impregnation method were used to fabricate polyethylene glycol (PEG)/hierarchical porous scaffold composite phase change materials (PCMs). Hierarchically interconnected porous scaffolds of boron nitride (BN), with the aid of a small amount of graphene oxide (GO), endow the composite PCMs with high thermal conductivity, excellent shape-stability and efficient solar-to-electric energy conversion. The formation of a three-dimensional (3D) thermally conductive pathway in the composites contributes to improving the thermal conductivity up to 2.36 W m -1 K -1 at a relatively low content of BN (ca. 23 wt%). This work provides a route for thermally conductive and shape-stabilized composite PCMs used as energy storage materials.

Radiation resistant polypropylene blended with mobilizer,. antioxidants and nucleating agent

NASA Astrophysics Data System (ADS)

Shamshad, A.; Basfar, A. A.

2000-03-01

Post-irradiation storage of medical disposables prepared from isotactic polypropylene renders them brittle due to degradation. To avoid this, isotactic polypropylene [(is)PP] was blended with a mobilizer, dioctyl pthallate (DOP), three antioxidants (hindered amines and a secondary antioxidant) and benzoic acid to obtain radiation-resistant, thermally-stable and transparent material. Different formulations prepared were subjected to gamma radiation to doses of 25 and 50 kGy. Tests of breakage on bending after ageing in an oven at 70°C up to 12 months have shown that the addition of DOP and the antioxidants imparts improved radiation and thermal stability as compared to (is)PP alone or its blend with DOP. All the formulations irradiated or otherwise demonstrated excellent colour stability even after accelerated ageing at 70°C for prolonged periods.

Stability of Beriplast P fibrin sealant: storage and reconstitution.

PubMed

Eberhard, Ulrich; Broder, Martin; Witzke, Günther

2006-04-26

This study was performed to investigate the stability of Beriplast P fibrin sealant (FS) across a range of storage conditions, both pre- and post-reconstitution. Storage stability of the FS was evaluated during long-term refrigeration (24 months) with or without interim storage at elevated temperatures (40 degrees C for 1 week and 25 degrees C for 1 and 3 months). Stability of individual FS components was assessed by measuring: fibrinogen content, Factor XIII activity (FXIII), thrombin activity and aprotinin potency. The package integrity of each component was also checked (sterility testing, moisture content and pH). Storage stability was also evaluated by testing the reconstituted product for adhesion (tearing force testing after mixing the solutions) and sterility. Reconstitution stability was evaluated following 3-months' storage, for up to 50 h post-reconstitution using the same tests as for the storage stability investigations. Pre-defined specifications were met for fibrinogen content, Factor XIII activity, and thrombin activity, demonstrating storage stability. Package integrity and the functionality and sterility of the reconstituted product were confirmed throughout. Reconstitution stability was demonstrated for up to 50 h following reconstitution, in terms of both tearing force and sterility tests. In conclusion, the storage stability of Beriplast P was demonstrated over a range of 24-month storage schedules including interim exposure to elevated temperature, and the reconstituted product was stable for up to 50 h.

NETL CO 2 Storage prospeCtive Resource Estimation Excel aNalysis (CO 2-SCREEN) User's Manual

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanguinito, Sean M.; Goodman, Angela; Levine, Jonathan

This user’s manual guides the use of the National Energy Technology Laboratory’s (NETL) CO 2 Storage prospeCtive Resource Estimation Excel aNalysis (CO 2-SCREEN) tool, which was developed to aid users screening saline formations for prospective CO 2 storage resources. CO 2- SCREEN applies U.S. Department of Energy (DOE) methods and equations for estimating prospective CO 2 storage resources for saline formations. CO2-SCREEN was developed to be substantive and user-friendly. It also provides a consistent method for calculating prospective CO 2 storage resources that allows for consistent comparison of results between different research efforts, such as the Regional Carbon Sequestration Partnershipsmore » (RCSP). CO 2-SCREEN consists of an Excel spreadsheet containing geologic inputs and outputs, linked to a GoldSim Player model that calculates prospective CO 2 storage resources via Monte Carlo simulation.« less

CoNi2 S4 Nanoparticle/Carbon Nanotube Sponge Cathode with Ultrahigh Capacitance for Highly Compressible Asymmetric Supercapacitor.

PubMed

Cao, Xin; He, Jin; Li, Huan; Kang, Liping; He, Xuexia; Sun, Jie; Jiang, Ruibing; Xu, Hua; Lei, Zhibin; Liu, Zong-Huai

2018-05-30

Compared with other flexible energy-storage devices, the design and construction of the compressible energy-storage devices face more difficulty because they must accommodate large strain and shape deformations. In the present work, CoNi 2 S 4 nanoparticles/3D porous carbon nanotube (CNT) sponge cathode with highly compressible property and excellent capacitance is prepared by electrodepositing CoNi 2 S 4 on CNT sponge, in which CoNi 2 S 4 nanoparticles with size among 10-15 nm are uniformly anchored on CNT, causing the cathode to show a high compression property and gives high specific capacitance of 1530 F g -1 . Meanwhile, Fe 2 O 3 /CNT sponge anode with specific capacitance of 460 F g -1 in a prolonged voltage window is also prepared by electrodepositing Fe 2 O 3 nanosheets on CNT sponge. An asymmetric supercapacitor (CoNi 2 S 4 /CNT//Fe 2 O 3 /CNT) is assembled by using CoNi 2 S 4 /CNT sponge as positive electrode and Fe 2 O 3 /CNT sponge as negative electrode in 2 m KOH solution. It exhibits excellent energy density of up to 50 Wh kg -1 at a power density of 847 W kg -1 and excellent cycling stability at high compression. Even at a strain of 85%, about 75% of the initial capacitance is retained after 10 000 consecutive cycles. The CoNi 2 S 4 /CNT//Fe 2 O 3 /CNT device is a promising candidate for flexible energy devices due to its excellent compressibility and high energy density. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent Progress in Some Amorphous Materials for Supercapacitors.

PubMed

Li, Qing; Xu, Yuxia; Zheng, Shasha; Guo, Xiaotian; Xue, Huaiguo; Pang, Huan

2018-05-14

A breakthrough in technologies having "green" and sustainable energy storage conversion is urgent, and supercapacitors play a crucial role in this area of research. Owing to their unique porous structure, amorphous materials are considered one of the best active materials for high-performance supercapacitors due to their high specific capacity, excellent cycling stability, and fast charging rate. This Review summarizes the synthesis of amorphous materials (transition metal oxides, carbon-based materials, transition metal sulfides, phosphates, hydroxides, and their complexes) to highlight their electrochemical performance in supercapacitors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Performance Lithium-Ion Hybrid Capacitors Employing Fe3O4-Graphene Composite Anode and Activated Carbon Cathode.

PubMed

Zhang, Shijia; Li, Chen; Zhang, Xiong; Sun, Xianzhong; Wang, Kai; Ma, Yanwei

2017-05-24

Lithium-ion capacitors (LICs) are considered as promising energy storage devices to realize excellent electrochemical performance, with high energy-power output. In this work, we employed a simple method to synthesize a composite electrode material consisting of Fe 3 O 4 nanocrystallites mechanically anchored among the layers of three-dimensional arrays of graphene (Fe 3 O 4 -G), which exhibits several advantages compared with other traditional electrode materials, such as high Li storage capacity (820 mAh g -1 at 0.1 A g -1 ), high electrical conductivity, and improved electrochemical stability. Furthermore, on the basis of the appropriated charge balance between cathode and anode, we successfully fabricated Fe 3 O 4 -G//activated carbon (AC) soft-packaging LICs with a high energy density of 120.0 Wh kg -1 , an outstanding power density of 45.4 kW kg -1 (achieved at 60.5 Wh kg -1 ), and an excellent capacity retention of up to 94.1% after 1000 cycles and 81.4% after 10 000 cycles. The energy density of the Fe 3 O 4 -G//AC hybrid device is comparable with Ni-metal hydride batteries, and its capacitive power capability and cycle life is on par with supercapacitors (SCs). Therefore, this lithium-ion hybrid capacitor is expected to bridge the gap between Li-ion battery and SCs and gain bright prospects in next-generation energy storage fields.

Controlled synthesis of MnOOH multilayer nanowires as anode materials for lithium-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Yue; Yue, Kaiqiang; Wang, Yuanxin

MnOOH multilayer nanowires have been successfully synthesized by a hydrothermal method. It is found that the uniform multilayer structure of nanowires ran through the entire nanowire, which is formed via a layer by layer. The electrochemical properties of MnOOH multilayer nanowires as an anode material for Li-ion batteries (LIB) were investigated, and excellent capacity retention, superior cycling performance, and high rate capability were achieved. Specifically, the reversible capacity of MnOOH multilayer nanowires is 521 mAh/g after 500 cycles at 0.1 C, with excellent electrochemical stability. The multilayer nanowire electrodes exhibit short electron path lengths, high internal dislocation densities and largemore » surface to volume ratio, resulting in increased specific capacity, cycling stability and rate performance in the energy storage devices, which serves as an indication of their potential application in LIBs. - Highlights: •MnOOH multilayer nanowires were synthesized by a hydrothermal method. •The uniform multilayer structure of nanowires was formed via layer by layer. •The reversible capacity of product shows 521 mAh/g after 500 cycles at 0.1 C. •MnOOH multilayer nanowires showed higher property as anode material in LIB.« less

High-performance flexible all-solid-state supercapacitors based on densely-packed graphene/polypyrrole nanoparticle papers

NASA Astrophysics Data System (ADS)

Yang, Chao; Zhang, Liling; Hu, Nantao; Yang, Zhi; Wei, Hao; Wang, Yanyan; Zhang, Yafei

2016-11-01

Graphene-based all-solid-state supercapacitors (ASSSCs) have received increasing attention. It's a great challenge to fabricate high-performance flexible solid-state supercapacitors with high areal and volumetric energy storage capability, superior electron and ion conductivity, robust mechanical flexibility, as well as long term stability. Herein, we report a facile method to fabricate flexible ASSSCs based on densely-packed reduced graphene oxide (rGO)/polypyrrole nanoparticle (PPy NP) hybrid papers with a sandwich framework, which consists of well-separated and continuously-aligned rGO sheets. The incorporation of PPy NPs not only provides pseudocapacitance but also facilitates the infiltration of gel electrolyte. The assembled ASSSCs possess maximum areal and volumetric specific capacitances of 477 mF/cm2 and 94.9 F/cm3 at 0.5 mA/cm2. They also exhibit little capacitance deviation under different bending states, excellent cycling stability, small leakage current and low self-discharge characteristics. Additionally, the maximum areal and volumetric energy densities of 132.5 μWh/cm2 and 26.4 mWh/cm3 are achieved, which indicate that this hybrid paper is a promising candidate for high-performance flexible energy storage devices.

Construction of NiO/MnO2/CeO2 hybrid nanoflake arrays as platform for electrochemical energy storage

NASA Astrophysics Data System (ADS)

Cui, Lihua; Cui, Jiewu; Zheng, Hongmei; Wang, Yan; Qin, Yongqiang; Shu, Xia; Liu, Jiaqin; Zhang, Yong; Wu, Yucheng

2017-09-01

Rational design and fabrication of novel electrode materials are of great importance for developing supercapacitors with remarkable capacitance and enhanced cycling stability. In this paper, we present a simple one-pot hydrothermal deposition followed by calcinations process for the in situ construction of homogeneous NiO/MnO2/CeO2 (NMC) nanoflake arrays on Ni foam substrate, which could be directly adopted as the binder-free electrode materials for high performance supercapacitors. The field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) are carried out to investigate the morphology, microstructure and composition of NMC nanoflake arrays. As-prepared hierarchical NMC nanoflake arrays exhibit the specific capacitance of 1027.8 F g-1 at a current density of 3.1 A g-1 and excellent cycling stability of 97.8% after 5000 charge/discharge cycles. This facile, cost-effective and controllable fabrication route and the robust supercapacitive activity suggest that the ordered NMC nanoflake arrays could be promising candidate electrode materials for high performance electrochemical energy storage devices.

Reverse microemulsion synthesis of nickel-cobalt hexacyanoferrate/reduced graphene oxide nanocomposites for high-performance supercapacitors and sodium ion batteries

NASA Astrophysics Data System (ADS)

Qiu, Xiaoming; Liu, Yongchang; Wang, Luning; Fan, Li-Zhen

2018-03-01

Prussian blue analogues with tunable open channels are of fundamental and technological importance for energy storage systems. Herein, a novel facile synthesis of nickel-cobalt hexacyanoferrate/reduced graphene oxide (denoted as Ni-CoHCF/rGO) nanocomposite is realized by a reverse microemulsion method. The very fine Ni-CoHCF nanoparticles (10-20 nm) are homogeneously anchored on the surface of reduced graphene oxide by electrostatic adsorption and reduced graphene oxide is well-separated by Ni-CoHCF particles. Benefiting from the combined advantages of this structure, the Ni-. It CoHCF/rGO nanocomposite can be used as electrodes for both supercapacitors and sodium ion batteries exhibits excellent pseudocapacitve performance in terms of high specific capacitance of 466 F g-1 at 0.2 A g-1 and 350 F g-1 at 10 A g-1, along with high cycling stabilities. As a cathode material for sodium ion batteries, it also demonstrates a high reversible capacity of 118 mAh g-1 at 0.1 A g-1, good rate capability, and superior cycling stability. These results suggest its potential as an efficient electrode for high-performance energy storage and renewable delivery devices.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, Yandong; Zhang, Bingkai; Zheng, Jiaxin

Abstract. Due to the enhanced kinetic properties, nanocrystallites have received much attention as potential electrode materials for energy storage. However, because of the large specific surface areas of nanocrystallites, they usually suffer from decreased energy density, reduced cycling stability and total electrode capacity. In this work, we report a size-dependent excess capacity beyond the theoretical value of 170 mAhg-1 in a special carbon coated LiFePO4 composite cathode material, which delivers capacities of 191.2 and 213.5 mAhg-1 with the mean particle sizes of 83 nm and 42 nm, respectively. Moreover, this LiFePO4 composite also shows excellent cycling stability and high ratemore » performance. Our further experimental tests and ab initio calculations reveal that the excess capacity comes from the charge passivation for which the C-O-Fe bonds would lead to charge redistribution on the surface of LiFePO4 and hence to enhance the bonding interaction between surface O atoms and Li-ions. The surface reconstruction for excess Li-ion storage makes full use of the large specific surface area for the nanocrystallites, which can maintain the fast Li-ion transport and enhance the capacity greatly that the nanocrystallites usually suffers.« less

Enhanced recoverable energy storage density and high efficiency of SrTiO3-based lead-free ceramics

NASA Astrophysics Data System (ADS)

Yang, Haibo; Yan, Fei; Lin, Ying; Wang, Tong

2017-12-01

In this study, (1-x)SrTiO3-x(Bi0.48La0.02Na0.48Li0.02Ti0.98Zr0.02O3) [(1-x)ST-xBLNLTZ] lead-free ceramics with x = 0-0.4 were designed and fabricated using the tape casting process and the subsequent conventional solid-state sintering method. The (1-x)ST-xBLNLTZ ceramics are characterized by the excellent frequency stability of the dielectric constant, large maximum polarization (Pmax), low remnant polarization (Pr), and slim polarization-electric field (P-E) loops. For the composition of x = 0.4, Pmax is increased to 30.35 μC/cm2, 3.82 times higher than that of pure SrTiO3 (7.95 μC/cm2). The breakdown strength is larger than 200 kV/cm for all the samples. The sample with x = 0.1 exhibits a high recoverable energy storage density (Wrec) of 2.59 J/cm3 and a high energy storage efficiency (η) of 85% simultaneously. The results demonstrate that the (1-x)ST-xBLNLTZ ceramics are promising lead-free materials for high energy storage applications.

Ultra-tiny ZnMn2O4 nanoparticles encapsulated in sandwich-like carbon nanosheets for high-performance supercapacitors.

PubMed

Guan, Yongxin; Feng, Yangyang; Mu, Yanping; Fang, Ling; Zhang, Huijuan; Wang, Yu

2016-11-25

Known as an excellent energy storage material, ZnMn 2 O 4 has a wide range of applications in supercapacitors. In this report, a special sandwich-like structure of ZnMn 2 O 4 /C has been first designed and synthesized via a simple hydrothermal method and subsequent calcinations. The designed special sandwich-like structure can benefit ion exchange and remit the probable volume changes during a mass of electrochemical reactions. Furthermore, the porous carbon nanosheets, derived from low-cost glucose, can effectively increase ion flux. Therefore, the novel sandwich-like ZnMn 2 O 4 nanoparticles encapsulated in carbon nanosheets can undoubtedly demonstrate an exceptional electrochemical performance for SCs. In this work, the composite material with porous sandwich-like structure exhibits excellent cyclic stability for 5000 cycles (∼5% loss) and high specific capacitance of 1786 F g -1 .

Ultra-tiny ZnMn2O4 nanoparticles encapsulated in sandwich-like carbon nanosheets for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Guan, Yongxin; Feng, Yangyang; Mu, Yanping; Fang, Ling; Zhang, Huijuan; Wang, Yu

2016-11-01

Known as an excellent energy storage material, ZnMn2O4 has a wide range of applications in supercapacitors. In this report, a special sandwich-like structure of ZnMn2O4/C has been first designed and synthesized via a simple hydrothermal method and subsequent calcinations. The designed special sandwich-like structure can benefit ion exchange and remit the probable volume changes during a mass of electrochemical reactions. Furthermore, the porous carbon nanosheets, derived from low-cost glucose, can effectively increase ion flux. Therefore, the novel sandwich-like ZnMn2O4 nanoparticles encapsulated in carbon nanosheets can undoubtedly demonstrate an exceptional electrochemical performance for SCs. In this work, the composite material with porous sandwich-like structure exhibits excellent cyclic stability for 5000 cycles (˜5% loss) and high specific capacitance of 1786 F g-1.

Highly efficient growth of vertically aligned carbon nanotubes on Fe-Ni based metal alloy foils for supercapacitors

NASA Astrophysics Data System (ADS)

Amalina Raja Seman, Raja Noor; Asyadi Azam, Mohd; Ambri Mohamed, Mohd

2016-12-01

Supercapacitors are highly promising energy devices with superior charge storage performance and a long lifecycle. Construction of the supercapacitor cell, especially electrode fabrication, is critical to ensure good performance in applications. This work demonstrates direct growth of vertically aligned carbon nanotubes (CNTs) on Fe-Ni based metal alloy foils, namely SUS 310S, Inconel 600 and YEF 50, and their use in symmetric vertically aligned CNT supercapacitor electrodes. Alumina and cobalt thin film catalysts were deposited onto the foils, and then CNT growth was performed using alcohol catalytic chemical vapour deposition. By this method, vertically aligned CNTs were successfully grown and used directly as a binder-free supercapacitor electrode to deliver excellent electrochemical performance. The device showed relatively good specific capacitance, a superior rate capability and excellent cycle stability, maintaining about 96% capacitance up to 1000 cycles.

Dynamic and galvanic stability of stretchable supercapacitors.

PubMed

Li, Xin; Gu, Taoli; Wei, Bingqing

2012-12-12

Stretchable electronics are emerging as a new technological advancement, since they can be reversibly stretched while maintaining functionality. To power stretchable electronics, rechargeable and stretchable energy storage devices become a necessity. Here, we demonstrate a facile and scalable fabrication of full stretchable supercapacitor, using buckled single-walled carbon nanotube macrofilms as the electrodes, an electrospun membrane of elastomeric polyurethane as the separator, and an organic electrolyte. We examine the electrochemical performance of the fully stretchable supercapacitors under dynamic stretching/releasing modes in different stretching strain rates, which reveal the true performance of the stretchable cells, compared to the conventional method of testing the cells under a statically stretched state. In addition, the self-discharge of the supercapacitor and the electrochemical behavior under bending mode are also examined. The stretchable supercapacitors show excellent cyclic stability under electrochemical charge/discharge during in situ dynamic stretching/releasing.

Environmental Stability of Plasmonic Biosensors Based on Natural versus Artificial Antibody.

PubMed

Luan, Jingyi; Xu, Ting; Cashin, John; Morrissey, Jeremiah J; Kharasch, Evan D; Singamaneni, Srikanth

2018-06-13

Plasmonic biosensors based on the refractive index sensitivity of localized surface plasmon resonance (LSPR) are considered to be highly promising for on-chip and point-of-care biodiagnostics. However, most of the current plasmonic biosensors employ natural antibodies as biorecognition elements, which can easily lose their biorecognition ability upon exposure to environmental stressors (e.g., temperature and humidity). Plasmonic biosensors relying on molecular imprints as recognition elements (artificial antibodies) are hypothesized to be an attractive alternative for applications in resource-limited settings due to their excellent thermal, chemical, and environmental stability. In this work, we provide a comprehensive comparison of the stability of plasmonic biosensors based on natural and artificial antibodies. Although the natural antibody-based plasmonic biosensors exhibit superior sensitivity, their stability (temporal, thermal, and chemical) was found to be vastly inferior to those based on artificial antibodies. Our results convincingly demonstrate that these novel classes of artificial antibody-based plasmonic biosensors are highly attractive for point-of-care and resource-limited conditions where tight control over transport, storage, and handling conditions is not possible.

Benchmarking organic mixed conductors for transistors.

PubMed

Inal, Sahika; Malliaras, George G; Rivnay, Jonathan

2017-11-24

Organic mixed conductors have garnered significant attention in applications from bioelectronics to energy storage/generation. Their implementation in organic transistors has led to enhanced biosensing, neuromorphic function, and specialized circuits. While a narrow class of conducting polymers continues to excel in these new applications, materials design efforts have accelerated as researchers target new functionality, processability, and improved performance/stability. Materials for organic electrochemical transistors (OECTs) require both efficient electronic transport and facile ion injection in order to sustain high capacity. In this work, we show that the product of the electronic mobility and volumetric charge storage capacity (µC*) is the materials/system figure of merit; we use this framework to benchmark and compare the steady-state OECT performance of ten previously reported materials. This product can be independently verified and decoupled to guide materials design and processing. OECTs can therefore be used as a tool for understanding and designing new organic mixed conductors.

Three-dimensional thin film for lithium-ion batteries and supercapacitors.

PubMed

Yang, Yang; Peng, Zhiwei; Wang, Gunuk; Ruan, Gedeng; Fan, Xiujun; Li, Lei; Fei, Huilong; Hauge, Robert H; Tour, James M

2014-07-22

Three-dimensional heterogeneously nanostructured thin-film electrodes were fabricated by using Ta2O5 nanotubes as a framework to support carbon-onion-coated Fe2O3 nanoparticles along the surface of the nanotubes. Carbon onion layers function as microelectrodes to separate the two different metal oxides and form a nanoscale 3-D sandwich structure. In this way, space-charge layers were formed at the phase boundaries, and it provides additional energy storage by charge separation. These 3-D nanostructured thin films deliver both excellent Li-ion battery properties (stabilized at 800 mAh cm(–3)) and supercapacitor (up to 18.2 mF cm(–2)) performance owing to the synergistic effects of the heterogeneous structure. Thus, Li-ion batteries and supercapacitors are successfully assembled into the same electrode, which is promising for next generation hybrid energy storage and delivery devices.

Bifunctional Nitrogen-Doped Microporous Carbon Microspheres Derived from Poly(o-methylaniline) for Oxygen Reduction and Supercapacitors.

PubMed

He, Yanzhen; Han, Xijiang; Du, Yunchen; Song, Bo; Xu, Ping; Zhang, Bin

2016-02-17

Heteroatom-doped carbon materials have attracted significant attention because of their applications in oxygen reduction reaction (ORR) and supercapacitors. Here we demonstrate a facile poly(o-methylaniline)-derived fabrication of bifunctional microporous nitrogen-doped carbon microspheres (NCMSs) with high electrocatalytic activity and stability for ORR and energy storage in supercapacitors. At a pyrolysis temperature of 900 °C, the highly dispersed NCMSs present a high surface area (727.1 m(2) g(-1)), proper total content of doping N, and high concentration of quaternary N, which exhibit superior electrocatalytic activities for ORR to the commercial Pt/C catalysts, high specific capacitance (414 F g(-1)), and excellent durability, making them very promising for advanced energy conversion and storage. The presented conducting polymer-derived strategy may provide a new way for the fabrication of heteroatom-doped carbon materials for energy device applications.

DNA hydrogel-based supercapacitors operating in physiological fluids

PubMed Central

Hur, Jaehyun; Im, Kyuhyun; Hwang, Sekyu; Choi, ByoungLyong; Kim, Sungjee; Hwang, Sungwoo; Park, Nokyoung; Kim, Kinam

2013-01-01

DNA nanostructures have been attractive due to their structural properties resulting in many important breakthroughs especially in controlled assemblies and many biological applications. Here, we report a unique energy storage device which is a supercapacitor that uses nanostructured DNA hydrogel (Dgel) as a template and layer-by-layer (LBL)-deposited polyelectrolyte multilayers (PEMs) as conductors. Our device, named as PEM-Dgel supercapacitor, showed excellent performance in direct contact with physiological fluids such as artificial urine and phosphate buffered saline without any need of additional electrolytes, and exhibited almost no cytotoxicity during cycling tests in cell culture medium. Moreover, we demonstrated that the PEM-Dgel supercapacitor has greater charge-discharge cycling stability in physiological fluids than highly concentrated acid electrolyte solution which is normally used for supercapacitor operation. These conceptually new supercapacitors have the potential to be a platform technology for the creation of implantable energy storage devices for packageless applications directly utilizing biofluids. PMID:23412432

Freestanding, heat resistant microporous film for use in energy storage devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pekala, Richard W.; Cherukupalli, Srinivas; Waterhouse, Robert R.

Preferred embodiments of a freestanding, heat resistant microporous polymer film (10) constructed for use in an energy storage device (70, 100) implements one or more of the following approaches to exhibit excellent high temperature mechanical and dimensional stability: incorporation into a porous polyolefin film of sufficiently high loading levels of inorganic or ceramic filler material (16) to maintain porosity (18) and achieve low thermal shrinkage; use of crosslinkable polyethylene to contribute to crosslinking the polymer matrix (14) in a highly inorganic material-filled polyolefin film; and heat treating or annealing of biaxially oriented, highly inorganic material-filled polyolefin film above the meltingmore » point temperature of the polymer matrix to reduce residual stress while maintaining high porosity. The freestanding, heat resistant microporous polymer film embodiments exhibit extremely low resistance, as evidenced by MacMullin numbers of less than 4.5.« less

A Hollow-Structured Manganese Oxide Cathode for Stable Zn-MnO₂ Batteries.

PubMed

Guo, Xiaotong; Li, Jianming; Jin, Xu; Han, Yehu; Lin, Yue; Lei, Zhanwu; Wang, Shiyang; Qin, Lianjie; Jiao, Shuhong; Cao, Ruiguo

2018-05-05

Aqueous rechargeable zinc-manganese dioxide (Zn-MnO₂) batteries are considered as one of the most promising energy storage devices for large scale-energy storage systems due to their low cost, high safety, and environmental friendliness. However, only a few cathode materials have been demonstrated to achieve stable cycling for aqueous rechargeable Zn-MnO₂ batteries. Here, we report a new material consisting of hollow MnO₂ nanospheres, which can be used for aqueous Zn-MnO₂ batteries. The hollow MnO₂ nanospheres can achieve high specific capacity up to ~405 mAh g −1 at 0.5 C. More importantly, the hollow structure of birnessite-type MnO₂ enables long-term cycling stability for the aqueous Zn-MnO₂ batteries. The excellent performance of the hollow MnO₂ nanospheres should be due to their unique structural properties that enable the easy intercalation of zinc ions.

Elaboration of a microstructured inkjet-printed carbon electrochemical capacitor

NASA Astrophysics Data System (ADS)

Pech, David; Brunet, Magali; Taberna, Pierre-Louis; Simon, Patrice; Fabre, Norbert; Mesnilgrente, Fabien; Conédéra, Véronique; Durou, Hugo

Carbon-based micro-supercapacitors dedicated to energy storage in self-powered modules were fabricated with inkjet printing technology on silicon substrate. An ink was first prepared by mixing an activated carbon powder with a PTFE polymer binder in ethylene glycol stabilized with a surfactant then deposited by inkjet on patterned gold current collectors with the substrate heated at 140 °C in order to assure a good homogeneity. Electrochemical micro-capacitors with electrodes in an interdigital configuration were fabricated, and characterized using electrochemical techniques in 1 M Et 4NBF 4 propylene carbonate electrolyte. These micro-devices show an excellent capacitive behavior over a wide potential range of 2.5 V for a cell capacitance of 2.1 mF cm -2. The newly developed technology will allow the integration of the storage device as close as possible to the MEMS-based energy harvesting device, minimizing power losses through connections.

Measurement of the Structure and Molecular Dynamics of Ionic Solutions for Redox Flow Battery

NASA Astrophysics Data System (ADS)

Li, Zhixia; Robertson, Lily; Moore, Jeffery; Zhang, Yang

Redox flow battery (RFB) is a promising electrical energy storage technology with great potential to finally realize alternative energy sources for the next-generation vehicles and at grid scales. The design of RFB is unique as the power scales separately from the energy capacity. The latter depends on the size of storage tanks and the concentration of the active materials. Redox-active organic molecules are excellent candidates with high synthetic tunability for both redox properties as well as, importantly, solubility. However, upon increasing concentrations, the flow cell has less cycling stability and more capacity fade. Further, after charging the battery, the viscosity increases while the ionic conductivity decreases, and thus the cell becomes overall ineffective. To understand the mechanism of the increased viscosity, we performed differential scanning calorimetry, wide and small angle X-rays scattering, and quasi-elastic neutron scattering measurements. Herein, we will present the measurement results and relative analysis.

Na2MnSiO4 as an attractive high capacity cathode material for sodium-ion battery

NASA Astrophysics Data System (ADS)

Law, Markas; Ramar, Vishwanathan; Balaya, Palani

2017-08-01

Here we report a polyanion-based cathode material for sodium-ion batteries, Na2MnSiO4, registering impressive sodium storage performances with discharge capacity of 210 mAh g-1 at an average voltage of 3 V at 0.1 C, along with excellent long-term cycling stability (500 cycles at 1 C). Insertion/extraction of ∼1.5 mol of sodium ion per formula unit of the silicate-based compound is reported and the utilisation of Mn2+ ⇋ Mn4+ redox couple is also demonstrated by ex-situ XPS. Besides, this study involves a systematic investigation of influence of the electrolyte additive (with different content) on the sodium storage performance of Na2MnSiO4. The electrolyte additive forms an optimum protective passivation film on the electrode surface, successfully reducing manganese dissolution.

A High-Energy-Density Potassium Battery with a Polymer-Gel Electrolyte and a Polyaniline Cathode.

PubMed

Gao, Hongcai; Xue, Leigang; Xin, Sen; Goodenough, John B

2018-05-04

A safe, rechargeable potassium battery of high energy density and excellent cycling stability has been developed. The anion component of the electrolyte salt is inserted into a polyaniline cathode upon charging and extracted from it during discharging while the K + ion of the KPF 6 salt is plated/stripped on the potassium-metal anode. The use of a p-type polymer cathode increases the cell voltage. By replacing the organic-liquid electrolyte in a glass-fiber separator with a polymer-gel electrolyte of cross-linked poly(methyl methacrylate), a dendrite-free potassium anode can be plated/stripped, and the electrode/electrolyte interface is stabilized. The potassium anode wets the polymer, and the cross-linked architecture provides small pores of adjustable sizes to stabilize a solid-electrolyte interphase formed at the anode/electrolyte interface. This alternative electrolyte/cathode strategy offers a promising new approach to low-cost potassium batteries for the stationary storage of electric power. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanofoaming to Boost the Electrochemical Performance of Ni@Ni(OH)2 Nanowires for Ultrahigh Volumetric Supercapacitors.

PubMed

Xu, Shusheng; Li, Xiaolin; Yang, Zhi; Wang, Tao; Jiang, Wenkai; Yang, Chao; Wang, Shuai; Hu, Nantao; Wei, Hao; Zhang, Yafei

2016-10-10

Three-dimensional free-standing film electrodes have aroused great interest for energy storage devices. However, small volumetric capacity and low operating voltage limit their practical application for large energy storage applications. Herein, a facile and novel nanofoaming process was demonstrated to boost the volumetric electrochemical capacitance of the devices via activation of Ni nanowires to form ultrathin nanosheets and porous nanostructures. The as-designed free-standing Ni@Ni(OH) 2 film electrodes display a significantly enhanced volumetric capacity (462 C/cm 3 at 0.5 A/cm 3 ) and excellent cycle stability. Moreover, the as-developed hybrid supercapacitor employed Ni@Ni(OH) 2 film as positive electrode and graphene-carbon nanotube film as negative electrode exhibits a high volumetric capacitance of 95 F/cm 3 (at 0.25 A/cm 3 ) and excellent cycle performance (only 14% capacitance reduction for 4500 cycles). Furthermore, the volumetric energy density can reach 33.9 mWh/cm 3 , which is much higher than that of most thin film lithium batteries (1-10 mWh/cm 3 ). This work gives an insight for designing high-volume three-dimensional electrodes and paves a new way to construct binder-free film electrode for high-performance hybrid supercapacitor applications.

Oxygen- and Nitrogen-Enriched 3D Porous Carbon for Supercapacitors of High Volumetric Capacity.

PubMed

Li, Jia; Liu, Kang; Gao, Xiang; Yao, Bin; Huo, Kaifu; Cheng, Yongliang; Cheng, Xiaofeng; Chen, Dongchang; Wang, Bo; Sun, Wanmei; Ding, Dong; Liu, Meilin; Huang, Liang

2015-11-11

Efficient utilization and broader commercialization of alternative energies (e.g., solar, wind, and geothermal) hinges on the performance and cost of energy storage and conversion systems. For now and in the foreseeable future, the combination of rechargeable batteries and electrochemical capacitors remains the most promising option for many energy storage applications. Porous carbonaceous materials have been widely used as an electrode for batteries and supercapacitors. To date, however, the highest specific capacitance of an electrochemical double layer capacitor is only ∼200 F/g, although a wide variety of synthetic approaches have been explored in creating optimized porous structures. Here, we report our findings in the synthesis of porous carbon through a simple, one-step process: direct carbonization of kelp in an NH3 atmosphere at 700 °C. The resulting oxygen- and nitrogen-enriched carbon has a three-dimensional structure with specific surface area greater than 1000 m(2)/g. When evaluated as an electrode for electrochemical double layer capacitors, the porous carbon structure demonstrated excellent volumetric capacitance (>360 F/cm(3)) with excellent cycling stability. This simple approach to low-cost carbonaceous materials with unique architecture and functionality could be a promising alternative to fabrication of porous carbon structures for many practical applications, including batteries and fuel cells.

Dual-carbon enhanced silicon-based composite as superior anode material for lithium ion batteries

NASA Astrophysics Data System (ADS)

Wang, Jie; Liu, Dai-Huo; Wang, Ying-Ying; Hou, Bao-Hua; Zhang, Jing-Ping; Wang, Rong-Shun; Wu, Xing-Long

2016-03-01

Dual-carbon enhanced Si-based composite (Si/C/G) has been prepared via employing the widely distributed, low-cost and environmentally friendly Diatomite mineral as silicon raw material. The preparation processes are very simple, non-toxic and easy to scale up. Electrochemical tests as anode material for lithium ion batteries (LIBs) demonstrate that this Si/C/G composite exhibits much improved Li-storage properties in terms of superior high-rate capabilities and excellent cycle stability compared to the pristine Si material as well as both single-carbon modified composites. Specifically for the Si/C/G composite, it can still deliver a high specific capacity of about 470 mAh g-1 at an ultrahigh current density of 5 A g-1, and exhibit a high capacity of 938 mAh g-1 at 0.1 A g-1 with excellent capacity retention in the following 300 cycles. The significantly enhanced Li-storage properties should be attributed to the co-existence of both highly conductive graphite and amorphous carbon in the Si/C/G composite. While the former can enhance the electrical conductivity of the obtained composite, the latter acts as the adhesives to connect the porous Si particulates and conductive graphite flakes to form robust and stable conductive network.

Oil-in-water emulsions as a delivery system for n-3 fatty acids in meat products.

PubMed

Salminen, Hanna; Herrmann, Kurt; Weiss, Jochen

2013-03-01

The oxidative and physical stabilities of oil-in-water emulsions containing n-3 fatty acids (25 wt.% oil, 2.5 wt.% whey protein, pH 3.0 or pH 6.0), and their subsequent incorporation into meat products were investigated. The physical stability of fish oil emulsions was excellent and neither coalescence nor aggregation occurred during storage. Oxidative stability was better at pH 6.0 compared to pH 3.0 likely due to antioxidative continuous phase proteins. Incorporation of fish oil emulsions into pork sausages led to an increase in oxidation compared to sausages without the added fish oil emulsion. Confocal microscopy of pork sausages with fish oil emulsions revealed that droplets had coalesced in the meat matrix over time which may have contributed to the decreased oxidative stability. Results demonstrate that although interfacial engineering of n-3 fatty acids containing oil-in-water emulsions provides physical and oxidative stability of the base-emulsion, their incorporation into complex meat matrices is a non-trivial undertaking and products may incur changes in quality over time. Copyright © 2012 Elsevier Ltd. All rights reserved.

Nanostructured porous carbons with high rate cycling and floating performance for supercapacitor application

NASA Astrophysics Data System (ADS)

Ochai-Ejeh, F. O.; Momodu, D. Y.; Madito, M. J.; Khaleed, A. A.; Oyedotun, K. O.; Ray, S. C.; Manyala, N.

2018-05-01

Biomass-derived activated carbon from cork (Quercus Suber) (ACQS) was prepared via a two-step environment-friendly route using mild KHCO3 as the activating agent. This synthesis route makes the material produced less toxic for usage as electrode material for energy storage application. The ACQS has well-defined microporous and mesoporous structures and a specific surface area of 1056.52 m2 g-1 and pore volume of 0.64 cm3 g-1. Three-electrode tests were performed in 6 M KOH, 1 M H2SO4 and 3 M KNO3 aqueous electrolytes, to analyse the material performance in acidic, basic, and neutral media. Specific capacitance values (Cs) of 133 F g-1/167 F g-1 at 1.0 A g-1 was obtained in 3 M KNO3 in the positive/negative potential windows. Due to the observed best performance in neutral 3 M KNO3, further electrochemical analysis of the symmetric device was carried out using the same electrolyte. The device displayed a Cs value of 122 F g-1, energy and power densities of ˜14 W h kg-1 and 450 W kg-1 respectively; at 0.5 A g-1. The device also displayed an excellent stability after potentiostatic floating at a maximum voltage of 1.8 V for 120 h and ˜100% capacitance retention after 10,000 charge-discharge cycles. The excellent stability makes the cork-derived material a potential excellent, cost-effective material for supercapacitor application.

NbS2 Nanosheets with M/Se (M = Fe, Co, Ni) Codopants for Li+ and Na+ Storage.

PubMed

Zhang, Jianli; Du, Chengfeng; Dai, Zhengfei; Chen, Wei; Zheng, Yun; Li, Bing; Zong, Yun; Wang, Xin; Zhu, Junwu; Yan, Qingyu

2017-10-24

Transition metal (M = Fe, Co, Ni) and Se codoped two-dimensional uniform NbS 2 (M x Nb 1-x S 2-y Se y ) nanosheets were synthesized via a facile oil-phase synthetic process. The morphology of M x Nb 1-x S 2-y Se y can be adjusted by tuning the amount of metal and Se introduced into NbS 2 . Among them, the optimized Fe 0.3 Nb 0.7 S 1.6 Se 0.4 nanosheets, with lateral sizes of 1-2 μm and approximately 5 nm thick, achieve the best Li-ion and Na-ion storage properties. For example, the Fe 0.3 Nb 0.7 S 1.6 Se 0.4 nanosheets depict excellent rate capabilities with fifth-cycle specific capacities of 461.3 mAh g -1 at 10 A g -1 for Li storage and 136 mAh g -1 at 5 A g -1 for Na storage. More significantly, ultralong cyclic stabilities were achieved with reversible specific capacities of 444 mAh g -1 at 5 A g -1 during the 3000th cycle for Li storage and 250 mAh g -1 at 1 A g -1 during the 750th cycle for Na storage. Post-treatment high-resolution transmission electron microscopy was studied to prove that the reversible Li-ion storage in NbS 2 was based on a conversion reaction mechanism.

A Facile Route to Metal Oxides/Single-Walled Carbon Nanotube Macrofilm Nanocomposites for Energy Storage

NASA Astrophysics Data System (ADS)

Cao, Zeyuan; Wei, Bingqing

2015-05-01

Nanocomposites consisting of transition-metal oxides and carbon nanomaterials with a desired size and structure are highly demanded for high performance energy storage devices. Here, a facile two-step and cost-efficient approach relying on directly thermal treatment of chemical-vapor-deposition products is developed as a general synthetic method to prepare a family of metal oxides (MxOy (M=Fe, Co, Ni))/single-walled carbon nanotube (SWNT) macrofilm nanocomposites. The MxOy nanoparticles obtained are of 3-17 nm in diameter and homogeneously anchor on the free-standing SWNT macrofilms. NiO/SWNT also exhibits a high specific capacitance of 400 F g-1 and fast charge-transfer Faradaic redox reactions to achieve asymmetric supercapacitors with a high power and energy density. All MxOy/SWNT nanocomposites could deliver a high capacity beyond 1000 mAh g-1 and show excellent cycling stability for lithium-ion batteries. The impressive results demonstrate the promise for energy storage devices and the general approach may pave the way to synthesize other functional nanocomposites.

Porphyrin-Based Symmetric Redox-Flow Batteries towards Cold-Climate Energy Storage.

PubMed

Ma, Ting; Pan, Zeng; Miao, Licheng; Chen, Chengcheng; Han, Mo; Shang, Zhenfeng; Chen, Jun

2018-03-12

Electrochemical energy storage with redox-flow batteries (RFBs) under subzero temperature is of great significance for the use of renewable energy in cold regions. However, RFBs are generally used above 10 °C. Herein we present non-aqueous organic RFBs based on 5,10,15,20-tetraphenylporphyrin (H 2 TPP) as a bipolar redox-active material (anode: [H 2 TPP] 2- /H 2 TPP, cathode: H 2 TPP/[H 2 TPP] 2+ ) and a Y-zeolite-poly(vinylidene fluoride) (Y-PVDF) ion-selective membrane with high ionic conductivity as a separator. The constructed RFBs exhibit a high volumetric capacity of 8.72 Ah L -1 with a high voltage of 2.83 V and excellent cycling stability (capacity retention exceeding 99.98 % per cycle) in the temperature range between 20 and -40 °C. Our study highlights principles for the design of RFBs that operate at low temperatures, thus offering a promising approach to electrochemical energy storage under cold-climate conditions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of Fe3O4 cluster microspheres/graphene aerogels composite as anode for high-performance lithium ion battery

NASA Astrophysics Data System (ADS)

Zhou, Shuai; Zhou, Yu; Jiang, Wei; Guo, Huajun; Wang, Zhixing; Li, Xinhai

2018-05-01

Iron oxides are considered as attractive electrode materials because of their capability of lithium storage, but their poor conductivity and large volume expansion lead to unsatisfactory cycling stability. We designed and synthesized a novel Fe3O4 cluster microspheres/Graphene aerogels composite (Fe3O4/GAs), where Fe3O4 nanoparticles were assembled into cluster microspheres and then embedded in 3D graphene aerogels framework. In the spheres, the sufficient free space between Fe3O4 nanoparticles could accommodate the volume change during cycling process. Graphene aerogel works as flexible and conductive matrix, which can not only significantly increase the mechanical stress, but also further improve the storage properties. The Fe3O4/GAs composite as an anode material exhibits high reversible capability and excellent cyclic capacity for lithium ion batteries (LIBs). A reversible capability of 650 mAh g-1 after 500 cycles at a current density of 1 A g-1 can be maintained. The superior storage capabilities of the composites make them potential anode materials for LIBs.

Stabilization of IgG1 in spray-dried powders for inhalation.

PubMed

Schüle, S; Schulz-Fademrecht, T; Garidel, P; Bechtold-Peters, K; Frieb, W

2008-08-01

The protein stabilizing capabilities of spray-dried IgG1/mannitol formulations were evaluated. The storage stability was tested at different residual moisture levels prepared by vacuum-drying or equilibration prior to storage. Vacuum-drying at 32 degrees C/0.1mbar for 24h reduced the moisture level below 1%, constituting an optimal basis for improved storage stability. The crystalline IgG1/mannitol powders with a weight ratio of 20/80 up to 40/60 failed to prevent the antibody aggregation as assessed by size exclusion chromatography during storage. Ratios of 60/40 up to 80/20 IgG1/mannitol provided superior stability of the antibody and the powders could be produced with high yields. The lower the residual moisture, the better was the stabilizing capability. An amount of 20% mannitol provided the best stabilization. Storage stability of 60/40, 70/30, and 80/20 IgG1/mannitol formulations over one year was adequate at 2-8 degrees C and 25 degrees C. Closed storage (sealed in vials) at 40 degrees C/75% RH and open storage at 25 degrees C/60% RH revealed that the stability still required optimization. The lower the protein content, the better was the powder flowability. The aerodynamic properties of powders spray-dried with 10% solids content were inadequate, as the particle size ranged between 5.1 and 7.2 microm and the fine particle fraction accounted for only 4-11%. Reduction of the solids content to 2.5% did improve the aerodynamic properties as the mass mean aerodynamic diameter was reduced to 3.6 microm and the fine particle fraction was increased to about 14%. The reduction of the solids content did not influence the storage stability significantly. Also spray-drying at higher temperatures had no significant impact on the storage stability, despite a higher tendency to form amorphous systems. In order to improve the storage stability and to maintain the good flowability of 70/30 IgG1/mannitol powder or to keep the storage stability but to improve the flowability of the 80/20 IgG1/mannitol powder, mannitol was partially substituted by a second excipient such as trehalose, sucrose, glycine, lactose, lactosucrose, or dextran 1. Differences in the stabilizing capability were noticeable upon closed storage at 40 degrees C/75% RH and open powder storage. Protein stabilization was improved by the addition of glycine but trehalose and sucrose were most effective in preventing aggregation, which can be primarily attributed to the water replacement properties of the sugars. The addition of another excipient, isoleucine had positive effects on both flowability and protein stability.

Porous Mn-doped cobalt oxide@C nanocomposite: a stable anode material for Li-ion rechargeable batteries

NASA Astrophysics Data System (ADS)

Kalubarme, Ramchandra S.; Jadhav, Sarika M.; Kale, Bharat B.; Gosavi, Suresh W.; Terashima, Chiaki; Fujishima, Akira

2018-07-01

Cobalt oxide is a transition metal oxide, well studied as an electrode material for energy storage applications, especially in supercapacitors and rechargeable batteries, due to its high charge storage ability. However, it suffers from low conductivity, which effectively hampers its long-term stability. In the present work, a simple strategy to enhance the conductivity of cobalt oxide is adopted to achieve stable electrochemical performance by means of carbon coating and Mn doping, via a simple and controlled, urea-assisted glycine-nitrate combustion process. Structural analysis of carbon coated Mn-doped Co3O4 (Mn-Co3O4@C) confirms the formation of nanoparticles (∼50 nm) with connected morphology, exhibiting spinel structure. The Mn-Co3O4@C electrode displays superior electrochemical performance as a Li-ion battery anode, delivering a specific capacity of 1250 mAh g‑1. Mn-Co3O4@C demonstrates excellent performance in terms of long-term stability, keeping charge storage ability intact even at high current rates due to the synergistic effects of fast kinetics—provided by enriched electronic conductivity, which allows ions to move freely to active sites and electrons from reaction sites to substrate during redox reactions—and high surface area combined with mesoporous architecture. The fully assembled battery device using Mn-Co3O4@C and standard LiCoO2 electrode shows 90% capacity retention over 100 cycles.

Encapsulating Silica/Antimony into Porous Electrospun Carbon Nanofibers with Robust Structure Stability for High-Efficiency Lithium Storage.

PubMed

Wang, Hongkang; Yang, Xuming; Wu, Qizhen; Zhang, Qiaobao; Chen, Huixin; Jing, Hongmei; Wang, Jinkai; Mi, Shao-Bo; Rogach, Andrey L; Niu, Chunming

2018-04-24

To address the volume-change-induced pulverization problems of electrode materials, we propose a "silica reinforcement" concept, following which silica-reinforced carbon nanofibers with encapsulated Sb nanoparticles (denoted as SiO 2 /Sb@CNFs) are fabricated via an electrospinning method. In this composite structure, insulating silica fillers not only reinforce the overall structure but also contribute to additional lithium storage capacity; encapsulation of Sb nanoparticles into the carbon-silica matrices efficiently buffers the volume changes during Li-Sb alloying-dealloying processes upon cycling and alleviates the mechanical stress; the porous carbon nanofiber framework allows for fast charge transfer and electrolyte diffusion. These advantageous characteristics synergistically contribute to the superior lithium storage performance of SiO 2 /Sb@CNF electrodes, which demonstrate excellent cycling stability and rate capability, delivering reversible discharge capacities of 700 mA h/g at 200 mA/g, 572 mA h/g at 500 mA/g, and 468 mA h/g at 1000 mA/g each after 400 cycles. Ex situ as well as in situ TEM measurements confirm that the structural integrity of silica-reinforced Sb@CNF electrodes can efficiently withstand the mechanical stress induced by the volume changes. Notably, the SiO 2 /Sb@CNF//LiCoO 2 full cell delivers high reversible capacities of ∼400 mA h/g after 800 cycles at 500 mA/g and ∼336 mA h/g after 500 cycles at 1000 mA/g.

In situ template synthesis of hollow nanospheres assembled from NiCo2S4@C ultrathin nanosheets with high electrochemical activities for lithium storage and ORR catalysis.

PubMed

Wu, Xiaoyu; Li, Songmei; Wang, Bo; Liu, Jianhua; Yu, Mei

2017-05-10

Transition-metal sulfide hollow nanostructures have received intensive attention in energy-related applications due to their unique structural features and high electrochemical activities. Here, a well-designed composite of NiCo 2 S 4 @C is successfully fabricated using a facile in situ template removal method. The obtained composite shows unique microstructures of hollow nanospheres (∼650 nm in diameter) assembled from ultrathin NiCo 2 S 4 @C nanosheets, in which numerous scattered NiCo 2 S 4 nanoparticles are embedded in ultrathin carbon nanosheets, exhibiting mesoporous features with a high surface area of 247.25 m 2 g -1 . When used as anode materials for LIBs, NiCo 2 S 4 @C hollow nanospheres exhibit a high reversible capacity of 1592 mA h g -1 at a current density of 500 mA g -1 , enhanced cycling performance maintaining a capacity of 1178 mA h g -1 after 200 cycles, and a remarkable rate capability. Meanwhile, the hollow nanospheres display excellent catalytic activity as ORR catalysts with a four-electron pathway and superior durability to that of commercial Pt/C catalysts. Their excellent lithium storage and ORR catalysis performance can be attributed to the rational incorporation of high-activity NiCo 2 S 4 and ultrathin carbon nanosheets, as well as unique hollow microstructures, which offer efficient electron/ion transport, an enhanced electroactive material/electrolyte contact area, numerous active sites, and excellent structural stability.

PNNL Development and Analysis of Material-Based Hydrogen Storage Systems for the Hydrogen Storage Engineering Center of Excellence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brooks, Kriston P.; Alvine, Kyle J.; Johnson, Kenneth I.

The Hydrogen Storage Engineering Center of Excellence is a team of universities, industrial corporations, and federal laboratories with the mandate to develop lower-pressure, materials-based, hydrogen storage systems for hydrogen fuel cell light-duty vehicles. Although not engaged in the development of new hydrogen storage materials themselves, it is an engineering center that addresses engineering challenges associated with the currently available hydrogen storage materials. Three material-based approaches to hydrogen storage are being researched: 1) chemical hydrogen storage materials 2) cryo-adsorbents, and 3) metal hydrides. As a member of this Center, Pacific Northwest National Laboratory (PNNL) has been involved in the design andmore » evaluation of systems developed with each of these three hydrogen storage materials. This report is a compilation of the work performed by PNNL for this Center.« less

Novel Nanocomposite Materials for Advanced Li-Ion Rechargeable Batteries

PubMed Central

Cai, Chuan; Wang, Ying

2009-01-01

Nanostructured materials lie at the heart of fundamental advances in efficient energy storage and/or conversion, in which surface processes and transport kinetics play determining roles. Nanocomposite materials will have a further enhancement in properties compared to their constituent phases. This Review describes some recent developments of nanocomposite materials for high-performance Li-ion rechargeable batteries, including carbon-oxide nanocomposites, polymer-oxide nanocomposites, metal-oxide nanocomposites, and silicon-based nanocomposites, etc. The major goal of this Review is to highlight some new progress in using these nanocomposite materials as electrodes to develop Li-ion rechargeable batteries with high energy density, high rate capability, and excellent cycling stability.

Iron-sulfide redox flow batteries

DOEpatents

Xia, Guanguang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

2016-06-14

Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

Iron-sulfide redox flow batteries

DOEpatents

Xia, Guan-Guang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

2013-12-17

Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

Fullerene-like MoSe2 nanoparticles-embedded CNT balls with excellent structural stability for highly reversible sodium-ion storage.

PubMed

Choi, Seung Ho; Kang, Yun Chan

2016-02-21

Three-dimensional (3D) porous-structured carbon nanotube (CNT) balls embedded with fullerene-like MoSe2 nanocrystals were successfully prepared by the spray pyrolysis process and subsequent selenization process. The MoO2-CNT composite balls prepared by spray pyrolysis transformed into the fullerene-like MoSe2/CNT (F-MoSe2/CNT) composite balls by the selenization process. The F-MoSe2/CNT composite balls exhibited superior sodium-ion storage properties to bare MoSe2 and MoSe2/CNT with a filled structure (N-MoSe2/CNT), both of which were prepared as comparison samples. The 250(th) discharge capacities of bare MoSe2, N-MoSe2/CNT composite balls, and F-MoSe2/CNT composite balls were 144, 200, and 296 mA h g(-1), respectively, at a high current density of 1.0 A g(-1), and their capacity retentions measured from the second cycle were 37%, 66%, and 83%, respectively. The 10(th) discharge capacities of the F-MoSe2/CNT composite balls were 382, 346, 310, 280, and 255 mA h g(-1) at current densities of 0.2, 0.5, 1.5, 3.0, and 5.0 A g(-1), respectively. The synergetic effect of the fullerene-like MoSe2 nanocrystals with ultrafine sizes and the CNT balls with a tangled and 3D porous structure and high electrical conductivity resulted in excellent sodium-ion storage properties of the F-MoSe2/CNT composite balls.

Cobalt Doping To Boost the Electrochemical Properties of Ni@Ni3 S2 Nanowire Films for High-Performance Supercapacitors.

PubMed

Xu, Shusheng; Wang, Tao; Ma, Yujie; Jiang, Wenkai; Wang, Shuai; Hong, Min; Hu, Nantao; Su, Yanjie; Zhang, Yafei; Yang, Zhi

2017-10-23

Metal sulfides have aroused great interest for energy storage. However, their low specific capacities and inferior rate capabilities hinder their practical applications. In this work, a facile cobalt-doping process is used to boost the electrochemical performance of Ni@Ni 3 S 2 core-sheath nanowire film electrodes for high-performance electrochemical energy storage. Co ions are doped successfully and uniformly into Ni 3 S 2 nanosheets through a facile ion-exchange process. The electrochemical properties of film electrodes are improved greatly, and an ultrahigh volumetric capacity (increased from 105 to 730 C cm -3 at 0.25 A cm -3 ) and excellent rate capability are obtained after Co is doped into Ni@Ni 3 S 2 core-sheath nanowires. A hybrid asymmetric supercapacitor with Co-doped Ni@Ni 3 S 2 as the positive electrode and graphene-carbon nanotubes as the negative electrode is assembled and exhibits an ultrahigh volumetric capacitance of 142 F cm -3 (based on the total volume of both electrodes) at 0.5 A cm -3 and excellent cycling stability (only 3 % capacitance decrease after 5000 cycles). Moreover, the volumetric energy density can reach 44.5 mWh cm -3 , which is much larger than those of thin-film lithium batteries (1-10 mWh cm -3 ). These results may provide useful insights for the fabrication of high-performance film electrodes for energy-storage applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

3D evaluation of the effect of disinfectants on dimensional accuracy and stability of two elastomeric impression materials.

PubMed

Soganci, Gokce; Cinar, Duygu; Caglar, Alper; Yagiz, Ayberk

2018-05-31

The aim of this study was to determine and compare the dimensional changes of polyether and vinyl polyether siloxane impression materials under immersion disinfection with two different disinfectants in three time periods. Impressions were obtained from an edentulous master model. Sodium hypochlorite (5.25%) and glutaraldehyde (2%) were used for disinfection and measurements were done 30 min later after making impression before disinfection, after required disinfection period (10 min), and after 24 h storage at room temperature. Impressions were scanned using 3D scanner with 10 microns accuracy and 3D software was used to evaluate the dimensional changes with superimpositioning. Positive and negative deviations were calculated and compared with master model. There was no significant difference between two elastomeric impression materials (p>0.05). It was concluded that dimensional accuracy and stability of two impression materials were excellent and similar.

Removal of water contaminants by nanoscale zero-valent iron immobilized in PAN-based oxidized membrane

NASA Astrophysics Data System (ADS)

Liu, Chunyi; Li, Xiang; Ma, Bomou; Qin, Aiwen; He, Chunju

2014-12-01

The functionalizing nanoporous polyacrylonitrile-based oxidized membrane (PAN-OM) firmly immobilized with highly reactive nanoscale zero-valent iron (NZVI) are successfully prepared via an innovative in situ synthesis method. Due to the formation of ladder structure, the PAN-OM present excellent thermal and chemical stabilities as a new carrier for the in-situ growth of NZVI via firm chelation and reduction action, respectively, which prevent the aggregation and release of NZVI. The developed NZVI-immobilized membrane present effective decolorizing efficiency to both anionic methyl blue and cationic methylene blue with a pseudo-first-order decay and degrading efficiency to trichloroethylene (TCE). The regeneration and stability results show that NZVI-immobilized membrane system can be regenerated without obvious performance reduction, which remain the reactivity after half a year storage period. These results suggest that PAN-based oxidized membrane immobilized with NZVI exhibit significant potential for environmental applications.

In Situ Synthesis of Vertical Standing Nanosized NiO Encapsulated in Graphene as Electrodes for High-Performance Supercapacitors.

PubMed

Lin, Jinghuang; Jia, Henan; Liang, Haoyan; Chen, Shulin; Cai, Yifei; Qi, Junlei; Qu, Chaoqun; Cao, Jian; Fei, Weidong; Feng, Jicai

2018-03-01

NiO is a promising electrode material for supercapacitors. Herein, the novel vertically standing nanosized NiO encapsulated in graphene layers (G@NiO) are rationally designed and synthesized as nanosheet arrays. This unique vertical standing structure of G@NiO nanosheet arrays can enlarge the accessible surface area with electrolytes, and has the benefits of short ion diffusion path and good charge transport. Further, an interconnected graphene conductive network acts as binder to encapsulate the nanosized NiO particles as core-shell structure, which can promote the charge transport and maintain the structural stability. Consequently, the optimized G@NiO hybrid electrodes exhibit a remarkably enhanced specific capacity up to 1073 C g -1 and excellent cycling stability. This study provides a facial strategy to design and construct high-performance metal oxides for energy storage.

Chitosan-induced Au/Ag nanoalloy dispersed in IL and application in fabricating an ultrasensitive glucose biosensor based on luminol-H₂O₂-Cu²⁺/IL chemiluminescence system.

PubMed

Chaichi, M J; Alijanpour, S O

2014-11-01

A novel glucose biosensor based on the chemiluminescence (CL) detection of enzymatically generated hydrogen peroxide (H₂O₂) was constructed by one covalent immobilization of glucose oxidase (GOD) in glutaraldehyde-functionalized glass cell. In following, chitosan-induced Au/Ag nanoparticles dispersed in ion liquid (IL) were synthesised and immobilized on it. Herein, chitosan molecules acted as both the reducing and stabilizing agent for the preparation of NPs and also, as a coupling agent GOD and Au/Ag alloy NPs. In addition to catalyze luminol CL reaction, these NPs offered excellent catalytic activity toward hydrogen peroxide generation in enzymatic reaction between GOD and glucose. The used IL in fabrication of biosensor increased its stability. Also, IL alongside Cu(2+) accelerated enzymatic and CL reaction kinetic, and decreased luminol CL reaction optimum pH to 7.5 which would enable sensitive and precision determination of glucose. Under optimum condition, linear response range of glucose was found to be 1.0 × 10(-6)-7.5 × 10(-3)M, and detection limit was 4.0 × 10(-7)M. The CL biosensor exhibited good storage stability, i.e., 90% of its initial response was retained after 2 months storage at pH 7.0. The present CL biosensor has been applied satisfactory to analysis of glucose in real serum and urine samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Solvothermal-induced self-assembly of Fe2O3/GS aerogels for high Li-storage and excellent stability.

PubMed

Wang, Ronghua; Xu, Chaohe; Du, Meng; Sun, Jing; Gao, Lian; Zhang, Peng; Yao, Heliang; Lin, Chucheng

2014-06-12

A novel solvothermal-induced self-assembly approach, using colloid sol as precursor, is developed to construct monolithic 3D metal oxide/GS (graphene sheets) aerogels. During the solvothermal process, graphene oxide (GO) is highly reduced to GS and self-assembles into 3D macroscopic hydrogels, accompanying with in situ transformation of colloid sol to metal oxides. As a proof of concept, Fe2 O3 /GS aerogels are synthesized based on Fe(OH)3 sol, in which GS self-assemble into an interconnected macroporous framework and Fe2 O3 nanocrystals (20-50 nm) uniformly deposit on GS. Benefitting from the integration of macroporous structures, large surface area, high electrical conductivity, and good electrode homogeneity, the hybrid electrode manifests a superior rate capability (930, 660 and 520 mAh g(-1) at 500, 2000 and 4000 mA g(-1), respectively) and excellent prolonged cycling stability at high rates (733 mAh g(-1) during 1000 charge/discharge cycles at 2000 mA g(-1)), demonstrating its great potential for application in high performance lithium ion batteries. The work described here provides a versatile pathway to construct various graphene-based hybrid aerogels. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Scalable Synthesis of Freestanding Sandwich-structured Graphene/Polyaniline/Graphene Nanocomposite Paper for Flexible All-Solid-State Supercapacitor

NASA Astrophysics Data System (ADS)

Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

2015-03-01

We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm-1), light weight (1 mg cm-2) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics.

High-Performance Flexible All-Solid-State Asymmetric Supercapacitors Based on Vertically Aligned CuSe@Co(OH) 2 Nanosheet Arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, Jiangfeng; Tian, Yazhou; Yang, Ziyuan

The developments of electrode active materials provide the opportunities for next-generation energy storage devices. The arrangement of electrode materials on the substrate has recently emerged as a promising strategy for preparing high-performance supercapacitors. In this paper, we demonstrate a novel vertically aligned CuSe@Co(OH) 2 nanosheet arrays electrode for supercapacitor application. The materials are thoroughly characterized by structural and spectroscopic techniques. Electrochemical performance of CuSe@Co(OH) 2 nanosheet arrays are investigated in detail, which exhibit a specific capacitance as much as 1180 F g -1 at a current density of 1 A g -1. A flexible asymmetric all-solid-state supercapacitor is fabricated usingmore » CuSe@Co(OH) 2 nanosheet arrays as the positive electrode and activated carbon as the negative electrode. The device delivers a volumetric capacitance of 441.4 mF cm -3 with maximum energy density and maximum power density is 0.17 and 62.1 mW cm -3, as well as robust cycling stability (~80.4% capacitance retention after 10 000 cycles), excellent flexibility, and mechanical stability. Finally, the excellent electrochemical performance can be attributed to its unique vertically aligned configuration.« less

Scalable Synthesis of Freestanding Sandwich-structured Graphene/Polyaniline/Graphene Nanocomposite Paper for Flexible All-Solid-State Supercapacitor

PubMed Central

Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

2015-01-01

We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm−1), light weight (1 mg cm−2) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics. PMID:25797022

High-Performance Flexible All-Solid-State Asymmetric Supercapacitors Based on Vertically Aligned CuSe@Co(OH) 2 Nanosheet Arrays

DOE PAGES

Gong, Jiangfeng; Tian, Yazhou; Yang, Ziyuan; ...

2018-01-04

The developments of electrode active materials provide the opportunities for next-generation energy storage devices. The arrangement of electrode materials on the substrate has recently emerged as a promising strategy for preparing high-performance supercapacitors. In this paper, we demonstrate a novel vertically aligned CuSe@Co(OH) 2 nanosheet arrays electrode for supercapacitor application. The materials are thoroughly characterized by structural and spectroscopic techniques. Electrochemical performance of CuSe@Co(OH) 2 nanosheet arrays are investigated in detail, which exhibit a specific capacitance as much as 1180 F g -1 at a current density of 1 A g -1. A flexible asymmetric all-solid-state supercapacitor is fabricated usingmore » CuSe@Co(OH) 2 nanosheet arrays as the positive electrode and activated carbon as the negative electrode. The device delivers a volumetric capacitance of 441.4 mF cm -3 with maximum energy density and maximum power density is 0.17 and 62.1 mW cm -3, as well as robust cycling stability (~80.4% capacitance retention after 10 000 cycles), excellent flexibility, and mechanical stability. Finally, the excellent electrochemical performance can be attributed to its unique vertically aligned configuration.« less

Composite of macroporous carbon with honeycomb-like structure from mollusc shell and NiCo(2)O(4) nanowires for high-performance supercapacitor.

PubMed

Xiong, Wei; Gao, Yongsheng; Wu, Xu; Hu, Xuan; Lan, Danni; Chen, Yangyang; Pu, Xuli; Zeng, Yan; Su, Jun; Zhu, Zhihong

2014-01-01

Novel biological carbon materials with highly ordered microstructure and large pore volume have caused great interest due to their multifunctional properties. Herein, we report the preparation of an interconnected porous carbon material by carbonizing the organic matrix of mollusc shell. The obtained three-dimensional carbon skeleton consists of hexangular and tightly arranged channels, which endow it with efficient electrolyte penetration and fast electron transfer, enable the mollusc shell based macroporous carbon material (MSBPC) to be an excellent conductive scaffold for supercapacitor electrodes. By growing NiCo2O4 nanowires on the obtained MSBPC, NiCo2O4/MSBPC composites were synthesized. When used on supercapacitor electrode, it exhibited anomalously high specific capacitance (∼1696 F/g), excellent rate performance (with the capacity retention of 58.6% at 15 A/g) and outstanding cycling stability (88% retention after 2000 cycles). Furthermore, an all-solid-state symmetric supercapacitor was also assembled based on this NiCo2O4/MSBPC electrode and showed good electrochemical performance with an energy density of 8.47 Wh/kg at 1 A/g, good stability over 10000 cycles. And we believe that more potential applications beyond energy storage can be developed based on this MSBPC.

Scalable synthesis of freestanding sandwich-structured graphene/polyaniline/graphene nanocomposite paper for flexible all-solid-state supercapacitor.

PubMed

Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

2015-03-23

We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm(-1)), light weight (1 mg cm(-2)) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics.

Hydrous Ruthenium Oxide Nanoparticles Anchored to Graphene and Carbon Nanotube Hybrid Foam for Supercapacitors

PubMed Central

Wang, Wei; Guo, Shirui; Lee, Ilkeun; Ahmed, Kazi; Zhong, Jiebin; Favors, Zachary; Zaera, Francisco; Ozkan, Mihrimah; Ozkan, Cengiz S.

2014-01-01

In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO2) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO2 nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g−1, areal capacitance: 1.11 F cm−2) which leads to an exceptionally high energy density of 39.28 Wh kg−1 and power density of 128.01 kW kg−1. The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications. PMID:24663242

Tin phosphide-based anodes for sodium-ion batteries: synthesis via solvothermal transformation of Sn metal and phase-dependent Na storage performance

PubMed Central

Shin, Hyun-Seop; Jung, Kyu-Nam; Jo, Yong Nam; Park, Min-Sik; Kim, Hansung; Lee, Jong-Won

2016-01-01

There is a great deal of current interest in the development of rechargeable sodium (Na)-ion batteries (SIBs) for low-cost, large-scale stationary energy storage systems. For the commercial success of this technology, significant progress should be made in developing robust anode (negative electrode) materials with high capacity and long cycle life. Sn-P compounds are considered promising anode materials that have considerable potential to meet the required performance of SIBs, and they have been typically prepared by high-energy mechanical milling. Here, we report Sn-P-based anodes synthesised through solvothermal transformation of Sn metal and their electrochemical Na storage properties. The temperature and time period used for solvothermal treatment play a crucial role in determining the phase, microstructure, and composition of the Sn-P compound and thus its electrochemical performance. The Sn-P compound prepared under an optimised solvothermal condition shows excellent electrochemical performance as an SIB anode, as evidenced by a high reversible capacity of ~560 mAh g−1 at a current density of 100 mA g−1 and cycling stability for 100 cycles. The solvothermal route provides an effective approach to synthesising Sn-P anodes with controlled phases and compositions, thus tailoring their Na storage behaviour. PMID:27189834

Hydrous ruthenium oxide nanoparticles anchored to graphene and carbon nanotube hybrid foam for supercapacitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Wei; Guo, S.; Lee, I.

2014-03-25

In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO₂) anchored graphene and CNT hybrid foam (RGM) architecturemore » for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO₂ nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g⁻¹, areal capacitance: 1.11 F cm⁻²) which leads to an exceptionally high energy density of 39.28 Wh kg⁻¹ and power density of 128.01 kW kg⁻¹. The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications.« less

Bulk to nanostructured vanadium pentaoxide-nanowires (V2O5-NWs) for high energy density supercapacitors

NASA Astrophysics Data System (ADS)

Ahirrao, Dinesh J.; Mohanapriya., K.; Jha, Neetu

2018-04-01

Vanadium pentoxide (V2O5) has attracted huge attention in field of energy storage including supercapacitor electrodes due to its low cost and layered structure. In this present study, Bulk V2O5 has been prepared by the calcination of ammonium metavanadate followed by the synthesis of V2O5-nanowires (V2O5-NWs) by hydrothermal treatment of bulk V2O5. Obtained V2O5-NWs was further used to fabricate the supercapacitor electrodes. Structure and morphology analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Energy storage capability of as prepared nanowires was investigated by Galvanostatic charge-discharge (GCD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in aqueous electrolyte (1M H2SO4). High specific capacitantance of about 622 F/g was achieved at 1 A/g. Along with high storage by faradic charge storage mechanism; V2O5-NWs electrodes also possess high stability. It could retain 63% of its initial capacitance even after 1000 GCD cycles. Excellent performance of V2O5-NWs promotes its commercial utilization for the development of high performance supercapacitors.

Design of Amorphous Manganese Oxide@Multiwalled Carbon Nanotube Fiber for Robust Solid-State Supercapacitor.

PubMed

Shi, Peipei; Li, Li; Hua, Li; Qian, Qianqian; Wang, Pengfei; Zhou, Jinyuan; Sun, Gengzhi; Huang, Wei

2017-01-24

Solid-state fiber-based supercapacitors have been considered promising energy storage devices for wearable electronics due to their lightweight and amenability to be woven into textiles. Efforts have been made to fabricate a high performance fiber electrode by depositing pseudocapacitive materials on the outer surface of carbonaceous fiber, for example, crystalline manganese oxide/multiwalled carbon nanotubes (MnO 2 /MWCNTs). However, a key challenge remaining is to achieve high specific capacitance and energy density without compromising the high rate capability and cycling stability. In addition, amorphous MnO 2 is actually preferred due to its disordered structure and has been proven to exhibit superior electrochemical performance over the crystalline one. Herein, by incorporating amorphous MnO 2 onto a well-aligned MWCNT sheet followed by twisting, we design an amorphous MnO 2 @MWCNT fiber, in which amorphous MnO 2 nanoparticles are distributed in MWCNT fiber uniformly. The proposed structure gives the amorphous MnO 2 @MWCNT fiber good mechanical reliability, high electrical conductivity, and fast ion-diffusion. Solid-state supercapacitor based on amorphous MnO 2 @MWCNT fibers exhibits improved energy density, superior rate capability, exceptional cycling stability, and excellent flexibility. This study provides a strategy to design a high performance fiber electrode with microstructure control for wearable energy storage devices.

A new high-energy cathode for a Na-ion battery with ultrahigh stability.

PubMed

Park, Young-Uk; Seo, Dong-Hwa; Kwon, Hyung-Soon; Kim, Byoungkook; Kim, Jongsoon; Kim, Haegyeom; Kim, Inkyung; Yoo, Han-Ill; Kang, Kisuk

2013-09-18

Large-scale electric energy storage is a key enabler for the use of renewable energy. Recently, the room-temperature Na-ion battery has been rehighlighted as an alternative low-cost technology for this application. However, significant challenges such as energy density and long-term stability must be addressed. Herein, we introduce a novel cathode material, Na1.5VPO4.8F0.7, for Na-ion batteries. This new material provides an energy density of ~600 Wh kg(-1), the highest value among cathodes, originating from both the multielectron redox reaction (1.2 e(-) per formula unit) and the high potential (~3.8 V vs Na(+)/Na) of the tailored vanadium redox couple (V(3.8+)/V(5+)). Furthermore, an outstanding cycle life (~95% capacity retention for 100 cycles and ~84% for extended 500 cycles) could be achieved, which we attribute to the small volume change (2.9%) upon cycling, the smallest volume change among known Na intercalation cathodes. The open crystal framework with two-dimensional Na diffusional pathways leads to low activation barriers for Na diffusion, enabling excellent rate capability. We believe that this new material can bring the low-cost room-temperature Na-ion battery a step closer to a sustainable large-scale energy storage system.

Fabrication of ultrathin solid electrolyte membranes of β-Li 3PS 4 nanoflakes by evaporation-induced self-assembly for all-solid-state batteries

DOE PAGES

Wang, Hui; Hood, Zachary D.; Xia, Younan; ...

2016-04-25

All-solid-state lithium batteries are attractive candidates for next-generation energy storage devices because of their anticipated high energy density and intrinsic safety. Owing to their excellent ionic conductivity and stability with metallic lithium anodes, nanostructured lithium thiophosphate solid electrolytes such as β-Li 3PS 4 have found use in the fabrication of all-solid lithium batteries for large-scale energy storage systems. However, current methods for preparing air-sensitive solid electrolyte membranes of lithium thiophosphates can only generate thick membranes that compromise the battery's gravimetric/volumetric energy density and thus its rate performance. To overcome this limitation, the solid electrolyte's thickness needs to be effectively decreasedmore » to achieve ideal energy density and enhanced rate performance. In this paper, we show that the evaporation-induced self-assembly (EISA) technique produces ultrathin membranes of a lithium thiophosphate solid electrolyte with controllable thicknesses between 8 and 50 μm while maintaining the high ionic conductivity of β-Li 3PS 4 and stability with metallic lithium anodes up to 5 V. Finally, it is clearly demonstrated that this facile EISA approach allows for the preparation of ultrathin lithium thiophosphate solid electrolyte membranes for all-solid-state batteries.« less

Liquid culture production of microsclerotia and submerged conidia by Trichoderma harzianum active against damping-off disease caused by Rhizoctonia solani.

PubMed

Kobori, Nilce N; Mascarin, Gabriel M; Jackson, Mark A; Schisler, David A

2015-04-01

Media and culturing protocols were identified that supported the formation of submerged conidia and microsclerotia (MS) by Trichoderma harzianum Rifai strain T-22 using liquid culture fermentation. Liquid media with a higher carbon concentration (36 g L(-1)) promoted MS formation at all C:N ratios tested. Hyphae aggregated to form MS after 2 d growth and after 7 d MS were fully melanized. This is the first report of MS formation by T. harzianum or any species of Trichoderma. Furthermore, submerged conidia formation was induced by liquid culture media, but yields, desiccation tolerance, and storage stability varied with C:N ratio and carbon rate. Air-dried MS granules (<4% moisture) retained excellent shelf life under cool and unrefrigerated storage conditions with no loss in conidial production. A low-cost complex nitrogen source based on cottonseed flour effectively supported high MS yields. Amending potting mix with dried MS formulations reduced or eliminated damping-off of melon seedlings caused by Rhizoctonia solani. Together, the results provide insights into the liquid culture production, stabilization process, and bioefficacy of the hitherto unreported MS of T. harzianum as a potential biofungicide for use in integrated management programs against soilborne diseases. Copyright © 2014 The British Mycological Society. All rights reserved.

Highly Porous FeS/Carbon Fibers Derived from Fe-Carrageenan Biomass: High-capacity and Durable Anodes for Sodium-Ion Batteries.

PubMed

Li, Daohao; Sun, Yuanyuan; Chen, Shuai; Yao, Jiuyong; Zhang, Yuhui; Xia, Yanzhi; Yang, Dongjiang

2018-05-08

The nanostructured metal sulfides have been reported as promising anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacities but have suffered from the unsatisfactory electronic conductivity and poor structural stability during a charge/discharge process, thus limiting their applications. Herein, the one-dimensional (1D) porous FeS/carbon fibers (FeS/CFs) micro/nanostructures are fabricated through facile pyrolysis of double-helix-structured Fe-carrageenan fibers. The FeS nanoparticles are in situ formed by interacting with sulfur-containing group of natural material ι-carrageenan and uniformly embedded in the unique 1D porous carbon fibrous matrix, significantly enhancing the sodium-ion storage performance. The obtained FeS/CFs with optimized sodium storage performance benefits from the appropriate carbon content (20.9 wt %). The composite exhibits high capacity and excellent cycling stability (283 mAh g -1 at current density of 1 A g -1 after 400 cycles) and rate performance (247 mAh g -1 at 5 A g -1 ). This work provides a simple strategy to construct 1D porous FeS/CFs micro/nanostructures as high-performance anode materials for SIBs via a unique sustainable and environmentally friendly way.

Multienzymatic amperometric biosensor based on gold and nanocomposite planar electrodes for glycerol determination in wine.

PubMed

Monošík, Rastislav; Ukropcová, Dana; Streďanský, Miroslav; Šturdík, Ernest

2012-02-01

Amperometric biosensors based on gold planar or nanocomposite electrode containing multiwalled carbon nanotubes for determination of glycerol were developed. The biosensors were constructed by immobilization of a novel multienzyme cascade consisting of glycerol kinase/creatine kinase/creatinase/sarcosine oxidase/peroxidase between a chitosan "sandwich." A measuring buffer contained adenosine 5'-triphosphate (ATP), creatine phosphate, and an artificial electrochemical mediator ferrocyanide. The currents proportional to glycerol concentration were measured at working potential of -50 mV against Ag/AgCl reference electrode. The biosensors showed linearity over the ranges of 5-640 μM and 5-566 μM with detection limits of 1.96 and 2.24 μM and sensitivities of 0.80 and 0.81 nA μM(-1), respectively. Both types of biosensors had a response time of 70s. The biosensors demonstrated satisfactory operational stability (no loss of sensitivity after 90 consecutive measurements) and excellent storage stability (90% of the initial sensitivity after 15 months of storage at room temperature). The results obtained from measurements of wines correlated well with those obtained with an enzymatic-spectrophotometric assay. The presented multienzyme cascade can be used also for determination of triglycerides or various kinase substrates when glycerol kinase is replaced by other kinases. Copyright © 2011 Elsevier Inc. All rights reserved.

Hierarchical Cobalt Hydroxide and B/N Co-Doped Graphene Nanohybrids Derived from Metal-Organic Frameworks for High Energy Density Asymmetric Supercapacitors

PubMed Central

Tabassum, Hassina; Mahmood, Asif; Wang, Qingfei; Xia, Wei; Liang, Zibin; Qiu, Bin; zhao, Ruo; Zou, Ruqiang

2017-01-01

To cater for the demands of electrochemical energy storage system, the development of cost effective, durable and highly efficient electrode materials is desired. Here, a novel electrode material based on redox active β-Co(OH)2 and B, N co-doped graphene nanohybrid is presented for electrochemical supercapacitor by employing a facile metal-organic frameworks (MOFs) route through pyrolysis and hydrothermal treatment. The Co(OH)2 could be firmly stabilized by dual protection of N-doped carbon polyhedron (CP) and B/N co-doped graphene (BCN) nanosheets. Interestingly, the porous carbon and BCN nanosheets greatly improve the charge storage, wettability, and redox activity of electrodes. Thus the hybrid delivers specific capacitance of 1263 F g−1 at a current density of 1A g−1 with 90% capacitance retention over 5000 cycles. Furthermore, the new aqueous asymmetric supercapacitor (ASC) was also designed by using Co(OH)2@CP@BCN nanohybrid and BCN nanosheets as positive and negative electrodes respectively, which leads to high energy density of 20.25 Whkg−1. This device also exhibits excellent rate capability with energy density of 15.55 Whkg−1 at power density of 9331 Wkg−1 coupled long termed stability up to 6000 cycles. PMID:28240224

Hierarchical Cobalt Hydroxide and B/N Co-Doped Graphene Nanohybrids Derived from Metal-Organic Frameworks for High Energy Density Asymmetric Supercapacitors.

PubMed

Tabassum, Hassina; Mahmood, Asif; Wang, Qingfei; Xia, Wei; Liang, Zibin; Qiu, Bin; Zhao, Ruo; Zou, Ruqiang

2017-02-27

To cater for the demands of electrochemical energy storage system, the development of cost effective, durable and highly efficient electrode materials is desired. Here, a novel electrode material based on redox active β-Co(OH) 2 and B, N co-doped graphene nanohybrid is presented for electrochemical supercapacitor by employing a facile metal-organic frameworks (MOFs) route through pyrolysis and hydrothermal treatment. The Co(OH) 2 could be firmly stabilized by dual protection of N-doped carbon polyhedron (CP) and B/N co-doped graphene (BCN) nanosheets. Interestingly, the porous carbon and BCN nanosheets greatly improve the charge storage, wettability, and redox activity of electrodes. Thus the hybrid delivers specific capacitance of 1263 F g -1 at a current density of 1A g -1 with 90% capacitance retention over 5000 cycles. Furthermore, the new aqueous asymmetric supercapacitor (ASC) was also designed by using Co(OH) 2 @CP@BCN nanohybrid and BCN nanosheets as positive and negative electrodes respectively, which leads to high energy density of 20.25 Whkg -1 . This device also exhibits excellent rate capability with energy density of 15.55 Whkg -1 at power density of 9331 Wkg -1 coupled long termed stability up to 6000 cycles.

Biaxially stretchable supercapacitors based on the buckled hybrid fiber electrode array

NASA Astrophysics Data System (ADS)

Zhang, Nan; Zhou, Weiya; Zhang, Qiang; Luan, Pingshan; Cai, Le; Yang, Feng; Zhang, Xiao; Fan, Qingxia; Zhou, Wenbin; Xiao, Zhuojian; Gu, Xiaogang; Chen, Huiliang; Li, Kewei; Xiao, Shiqi; Wang, Yanchun; Liu, Huaping; Xie, Sishen

2015-07-01

In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g-1. H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the fibers endow the supercapacitor with 100% stretchability along all directions. In addition, the supercapacitor exhibited good transparency, as well as excellent electrochemical properties and stability after being stretched 5000 times.In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g-1. H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the fibers endow the supercapacitor with 100% stretchability along all directions. In addition, the supercapacitor exhibited good transparency, as well as excellent electrochemical properties and stability after being stretched 5000 times. Electronic supplementary information (ESI) available: SEM images of the twist-first hybrid fiber, TEM images of SWCNT/PEDOT hybrid bundles, Raman spectra and FTIR spectra of the hybrid electrodes, CVs of the pristine, bended and wound supercapacitor, transmittance spectra of the pristine and stretched supercapacitor, demo video of the supercapacitor. See DOI: 10.1039/c5nr03027g

Trap Depth Engineering of SrSi2O2N2:Ln2+,Ln3+ (Ln2+ = Yb, Eu; Ln3+ = Dy, Ho, Er) Persistent Luminescence Materials for Information Storage Applications.

PubMed

Zhuang, Yixi; Lv, Ying; Wang, Le; Chen, Wenwei; Zhou, Tian-Liang; Takeda, Takashi; Hirosaki, Naoto; Xie, Rong-Jun

2018-01-17

Deep-trap persistent luminescence materials exhibit unique properties of energy storage and controllable photon release under additional stimulation, allowing for both wavelength and intensity multiplexing to realize high-capacity storage in the next-generation information storage system. However, the lack of suitable persistent luminescence materials with deep traps is the bottleneck of such storage technologies. In this study, we successfully developed a series of novel deep-trap persistent luminescence materials in the Ln 2+ /Ln 3+ -doped SrSi 2 O 2 N 2 system (Ln 2+ = Yb, Eu; Ln 3+ = Dy, Ho, Er) by applying the strategy of trap depth engineering. Interestingly, the trap depth can be tailored by selecting different codopants, and it monotonically increases from 0.90 to 1.18 eV in the order of Er, Ho, and Dy. This is well explained by the energy levels indicated in the host-referred binding energy scheme. The orange-red-emitting SrSi 2 O 2 N 2 :Yb,Dy and green-emitting SrSi 2 O 2 N 2 :Eu,Dy phosphors are demonstrated to be good candidates of information storage materials, which are attributed to their deep traps, narrow thermoluminescence glow bands, high emission efficiency, and excellent chemical stability. This work not only validates the suitability of deep-trap persistent luminescence materials in the information storage applications, but also broadens the avenue to explore such kinds of new materials for applications in anticounterfeiting and advanced displays.

Electrochemical characteristics of the reduced graphene oxide/carbon nanotube/polypyrrole composites for aqueous asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Peng, Yu-Jung; Wu, Tzu-Ho; Hsu, Chun-Tsung; Li, Shin-Ming; Chen, Ming-Guan; Hu, Chi-Chang

2014-12-01

Polypyrrole (PPy) has been polymerized onto reduced graphene oxide/carbon nanotube (rGO/CNT) to form an rGO/CNT/PPy composite using the chemical oxidation method. The electrochemical characteristics of the above composite in various aqueous electrolytes are systematically compared for the asymmetric supercapacitor application. The electrochemical characteristics of rGO/CNT/PPy in the electrolytes containing K+ show improved reversibility and higher stability. Introducing XC-72 in preparing the electrode has been found to enhance the specific capacitance and the cycle stability of rGO/CNT/PPy. The charge storage stability of rGO/CNT/PPy + XC-72 in various potential windows has been evaluated through the potential bias stress test. An asymmetric supercapacitor (ASC) with a positive electrode of Mn3O4 and a negative electrode of rGO/CNT/PPy + XC-72 is successfully demonstrated, which shows specific energy and power of 14. Wh kg-1 and 6.62 kW kg-1 with a cell voltage of 1.6 V. This ASC with a cell voltage of 1.6 V shows excellent charge-discharge cycle stability and ideal capacitive behavior in NaNO3 even after the application of 3250 charge-discharge cycles.

Raising the cycling stability of aqueous lithium-ion batteries by eliminating oxygen in the electrolyte.

PubMed

Luo, Jia-Yan; Cui, Wang-Jun; He, Ping; Xia, Yong-Yao

2010-09-01

Aqueous lithium-ion batteries may solve the safety problem associated with lithium-ion batteries that use highly toxic and flammable organic solvents, and the poor cycling life associated with commercialized aqueous rechargeable batteries such as lead-acid and nickel-metal hydride systems. But all reported aqueous lithium-ion battery systems have shown poor stability: the capacity retention is typically less than 50% after 100 cycles. Here, the stability of electrode materials in an aqueous electrolyte was extensively analysed. The negative electrodes of aqueous lithium-ion batteries in a discharged state can react with water and oxygen, resulting in capacity fading upon cycling. By eliminating oxygen, adjusting the pH values of the electrolyte and using carbon-coated electrode materials, LiTi(2)(PO(4))(3)/Li(2)SO(4)/LiFePO(4) aqueous lithium-ion batteries exhibited excellent stability with capacity retention over 90% after 1,000 cycles when being fully charged/discharged in 10 minutes and 85% after 50 cycles even at a very low current rate of 8 hours for a full charge/discharge offering an energy storage system with high safety, low cost, long cycling life and appropriate energy density.

Large-scale synthesis of water-soluble luminescent hydroxyapatite nanorods for security printing.

PubMed

Chen, Xiaohu; Jin, Xiaoying; Tan, Junjun; Li, Wei; Chen, Minfang; Yao, Lan; Yang, Haitao

2016-04-15

Luminescent hydroxyapatite nanoparticles, which have excellent biocompatibility, excellent photostability, and strong fluorescence, have received increasing attention as bioprobes in cell imaging. However, they are also excellent candidates for use in ink-jet security printing. Successful products for related applications usually require highly crystalline, mono-dispersible hydroxyapatite nanorods with good colloidal stability and high fluorescence in aqueous media. These requirements are hard to simultaneously satisfy using most synthetic methods. In this paper, we report a simple and versatile hydrothermal method that incorporates the use of sodium citrate to prepare water-dispersible Eu(3+)-doped hydroxyapatite nanorods. The hydroxyapatite nanorods obtained using this method are highly crystalline rod-shaped particles with an average length of 50-80 nm and an average diameter of 15-30 nm. Dispersions of these hydroxyapatite nanorods, which are transparent with a slightly milky color under natural light and a bright red color when excited with 241 nm UV light, display zeta potentials of -35 mV and hydrodynamic diameters of 120 nm. These dispersions remain colloidally stable for a few months. Dispersions with these properties could be easily applied to security printing for confidential information storage and anti-counterfeiting technologies. Copyright © 2016 Elsevier Inc. All rights reserved.

Polymeric micelles for parenteral delivery of sagopilone: physicochemical characterization, novel formulation approaches and their toxicity assessment in vitro as well as in vivo.

PubMed

Richter, Annett; Olbrich, Carsten; Krause, Michael; Hoffmann, Jens; Kissel, Thomas

2010-06-01

The block copolymers PEG(2000)-b-PLA(2200), PEG(2000)-b-PCL(2600) and PEG(5000)-b-PCL(5000) have been currently identified as optimal solubilizing agents for Sagopilone, a poorly water-soluble anticancer drug. In the present study, the stability, formulation feasibility and in vitro as well as in vivo toxicity were evaluated. Dispersion media, storage conditions, and dilutions were varied for stability assessment. The critical micelle concentration (CMC) was determined using a fluorescent probe technique. Lyophilizates and polymeric films were investigated as formulation options. Furthermore, the toxicity was studied in vitro and in vivo using HeLa/MaTu cells and a nude mouse model, respectively. A drug-polymer ratio as low as 1:20 (w/w) was sufficient to solubilize Sagopilone effectively and to obtain stable dispersions (24h: drug content >or= 95%). Although the micelles exhibited a similar thermodynamic stability (CMC: 10(-7)-10(-6)M), PEG-b-PCL micelles were kinetically more stable than PEG(2000)-b-PLA(2200) (24h at 37 degrees C: drug content >or= 90% compared to 30%, respectively). Lyophilization of PEG-b-PCL micelles and storage stability of solid drug-loaded PEG(2000)-b-PLA(2200) films (3m, 6 degrees C: drug content of (95.6+/-1.4)%) were demonstrated for the first time. The high antiproliferative activity has been maintained in vitro (IC(50)<1 nM). Carrier-associated side effects have not been observed in vivo and the maximum tolerated dose of micellar Sagopilone was determined to be 6 mg/kg. The results of this study indicate that polymeric micelles, especially PEG-b-PCL micelles, offer excellent potential for further preclinical and clinical cancer studies using Sagopilone. Copyright 2010 Elsevier B.V. All rights reserved.

Facile Synthesis of Nitrogen and Oxygen Co-Doped Clews of Carbon Nanobelts for Supercapacitors with Excellent Rate Performance.

PubMed

Yu, Liang; Zeng, Shaozhong; Zeng, Xierong; Li, Xiaohua; Wu, Hongliang; Yao, Yuechao; Tu, Wenxuan; Zou, Jizhao

2018-04-04

Facile synthesis of carbon materials with high heteroatom content, large specific surface area (SSA) and hierarchical porous structure is critical for energy storage applications. In this study, nitrogen and oxygen co-doped clews of carbon nanobelts (NCNBs) with hierarchical porous structures are successfully prepared by a carbonization and subsequent activation by using ladder polymer of hydroquinone and formaldehyde (LPHF) as the precursor and ammonia as the activating agent. The hierarchical porous structures and ultra-high SSA (up to 2994 m² g −1 ) can effectively facilitate the exchange and transportation of electrons and ions. Moreover, suitable heteroatom content is believed to modify the wettability of the carbon material. The as-prepared activated NCNBs-60 (the NCNBs activated by ammonia at 950 °C for 60 min) possess a high capacitance of 282 F g −1 at the current density of 0.25 A g −1 , NCNBs-45 (the NCNBs are activated by ammonia at 950 °C for 45 min) and show an excellent capacity retention of 50.2% when the current density increase from 0.25 to 150 A g −1 . Moreover, the NCNBs-45 electrode exhibits superior electrochemical stability with 96.2% capacity retention after 10,000 cycles at 5.0 A g −1 . The newly prepared NCNBs thus show great potential in the field of energy storage.

Facile Synthesis of Nitrogen and Oxygen Co-Doped Clews of Carbon Nanobelts for Supercapacitors with Excellent Rate Performance

PubMed Central

Yu, Liang; Zeng, Shaozhong; Zeng, Xierong; Li, Xiaohua; Wu, Hongliang; Yao, Yuechao; Tu, Wenxuan; Zou, Jizhao

2018-01-01

Facile synthesis of carbon materials with high heteroatom content, large specific surface area (SSA) and hierarchical porous structure is critical for energy storage applications. In this study, nitrogen and oxygen co-doped clews of carbon nanobelts (NCNBs) with hierarchical porous structures are successfully prepared by a carbonization and subsequent activation by using ladder polymer of hydroquinone and formaldehyde (LPHF) as the precursor and ammonia as the activating agent. The hierarchical porous structures and ultra-high SSA (up to 2994 m2 g−1) can effectively facilitate the exchange and transportation of electrons and ions. Moreover, suitable heteroatom content is believed to modify the wettability of the carbon material. The as-prepared activated NCNBs-60 (the NCNBs activated by ammonia at 950 °C for 60 min) possess a high capacitance of 282 F g−1 at the current density of 0.25 A g−1, NCNBs-45 (the NCNBs are activated by ammonia at 950 °C for 45 min) and show an excellent capacity retention of 50.2% when the current density increase from 0.25 to 150 A g−1. Moreover, the NCNBs-45 electrode exhibits superior electrochemical stability with 96.2% capacity retention after 10,000 cycles at 5.0 A g−1. The newly prepared NCNBs thus show great potential in the field of energy storage. PMID:29617315

Highly Stable Graphene-Based Nanocomposite (GO-PEI-Ag) with Broad-Spectrum, Long-Term Antimicrobial Activity and Antibiofilm Effects.

PubMed

Zhao, Rongtao; Kong, Wen; Sun, Mingxuan; Yang, Yi; Liu, Wanying; Lv, Min; Song, Shiping; Wang, Lihua; Song, Hongbin; Hao, Rongzhang

2018-05-30

Various silver nanoparticle (AgNP)-decorated graphene oxide (GO) nanocomposites (GO-Ag) have received increasing attention owing to their antimicrobial activity and biocompatibility; however, their aggregation in physiological solutions and the generally complex synthesis methods warrant improvement. This study aimed to synthesize a polyethyleneimine (PEI)-modified and AgNP-decorated GO nanocomposite (GO-PEI-Ag) through a facile approach through microwave irradiation without any extra reductants and surfactants; its antimicrobial activity was investigated on Gram-negative/-positive bacteria (including drug-resistant bacteria) and fungi. Compared with GO-Ag, GO-PEI-Ag acquired excellent stability in physiological solutions and electropositivity, showing substantially higher antimicrobial efficacy. Moreover, GO-PEI-Ag exhibited particularly excellent long-term effects, presenting no obvious decline in antimicrobial activity after 1 week storage in physiological saline and repeated use for three times and the lasting inhibition of bacterial growth in nutrient-rich culture medium. In contrast, GO-Ag exhibited a >60% decline in antimicrobial activity after storage. Importantly, GO-PEI-Ag effectively eliminated adhered bacteria, thereby preventing biofilm formation. The primary antimicrobial mechanisms of GO-PEI-Ag were evidenced as physical damage to the pathogen structure, causing cytoplasmic leakage. Hence, stable GO-PEI-Ag with robust, long-term antimicrobial activity holds promise in combating public-health threats posed by drug-resistant bacteria and biofilms.

Nanosized CoO Loaded on Copper Foam for High-Performance, Binder-Free Lithium-Ion Batteries.

PubMed

Liao, Mingna; Zhang, Qilun; Tang, Fengling; Xu, Zhiwei; Zhou, Xin; Li, Youpeng; Zhang, Yali; Yang, Chenghao; Ru, Qiang; Zhao, Lingzhi

2018-03-22

The synthesis of nanosized CoO anodes with unique morphologies via a hydrothermal method is investigated. By adjusting the pH values of reaction solutions, nanoflakes (CoO-NFs) and nanoflowers (CoO-FLs) are successfully located on copper foam. Compared with CoO-FLs, CoO-NFs as anodes for lithium ion batteries present ameliorated lithium storage properties, such as good rate capability, excellent cycling stability, and large CoO nanoflakes; CoO nanoflowers; anodes; binder free; lithium ion batteriesreversible capacity. The initial discharge capacity is 1470 mA h g -1 , while the reversible capacity is maintained at 1776 m Ah g -1 after 80 cycles at a current density of 100 mA h g -1 . The excellent electrochemical performance is ascribed to enough free space and enhanced conductivity, which play crucial roles in facilitating electron transport during repetitive Li⁺ intercalation and extraction reaction as well as buffering the volume expansion.

Ultra-stretchable conductors based on buckled super-aligned carbon nanotube films.

PubMed

Yu, Yang; Luo, Shu; Sun, Li; Wu, Yang; Jiang, Kaili; Li, Qunqing; Wang, Jiaping; Fan, Shoushan

2015-06-14

Ultra-stretchable conductors are fabricated by coating super-aligned carbon nanotube (SACNT) films on pre-strained polydimethylsiloxane (PDMS) substrates and forming buckled SACNT structures on PDMS after release of the pre-strain. The parallel SACNT/PDMS conductors demonstrate excellent stability with normalized resistance changes of only 4.1% under an applied strain as high as 200%. The SACNT/PDMS conductors prepared with cross-stacked SACNT films show even lower resistance variation. The parallel SACNT/PDMS conductors exhibit high durability with a resistance increase of less than 5% after 10,000 cycles at 150% strain. In situ microscopic observations demonstrate that the buckled SACNT structures are straightened during the stretching process with reversible morphology evolution and thus the continuous SACNT conductive network can be protected from fracture. Due to the excellent electrical and mechanical properties of SACNT films and the formation of the buckled structure, SACNT/PDMS films exhibit high stretchability and durability, possessing great potential for use as ultra-stretchable conductors for wearable electronics, sensors, and energy storage devices.

Evaluation of industrially applied heat-transfer fluids as liquid organic hydrogen carrier systems.

PubMed

Brückner, Nicole; Obesser, Katharina; Bösmann, Andreas; Teichmann, Daniel; Arlt, Wolfgang; Dungs, Jennifer; Wasserscheid, Peter

2014-01-01

Liquid organic hydrogen carrier (LOHC) systems offer a very attractive method for the decentralized storage of renewable excess energy. In this contribution, industrially well-established heat-transfer oils (typically sold under trade names, e.g., Marlotherm) are proposed as a new class of LOHC systems. It is demonstrated that the liquid mixture of isomeric dibenzyltoluenes (m.p. -39 to -34 °C, b.p. 390 °C) can be readily hydrogenated to the corresponding mixture of perhydrogenated analogues by binding 6.2 wt% of H2. The liquid H2 -rich form can be stored and transported similarly to diesel fuel. It readily undergoes catalytic dehydrogenation at temperatures above 260 °C, which proves its applicability as a reversible H2 carrier. The presented LOHC systems are further characterized by their excellent technical availability at comparably low prices, full registration of the H2 -lean forms, and excellent thermal stabilities. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evidence of covalent synergy in silicon–sulfur–graphene yielding highly efficient and long-life lithium-ion batteries

DOE PAGES

Hassan, Fathy M.; Batmaz, Rasim; Li, Jingde; ...

2015-10-26

Silicon has the potential to revolutionize the energy storage capacities of lithium-ion batteries to meet the ever increasing power demands of next generation technologies. To avoid the operational stability problems of silicon-based anodes, we propose synergistic physicochemical alteration of electrode structures during their design. This capitalizes on covalent interaction of Si nanoparticles with sulfur-doped graphene and with cyclized polyacrylonitrile to provide a robust nanoarchitecture. This hierarchical structure stabilized the solid electrolyte interphase leading to superior reversible capacity of over 1,000 mAh g -1 for 2,275 cycles at 2 A g -1. Furthermore, the nanoarchitectured design lowered the contact of themore » electrolyte to the electrode leading to not only high coulombic efficiency of 99.9% but also maintaining high stability even with high electrode loading associated with 3.4 mAh cm -2. As a result, the excellent performance combined with the simplistic, scalable and non-hazardous approach render the process as a very promising candidate for Li-ion battery technology.« less

New nanomicelle curcumin formulation for ocular delivery: improved stability, solubility, and ocular anti-inflammatory treatment.

PubMed

Li, Mengshuang; Xin, Meng; Guo, Chuanlong; Lin, Guiming; Wu, Xianggen

2017-11-01

A stable topical ophthalmic curcumin formulation with high solubility, stability, and efficacy is needed for pharmaceutical use in clinics. The objective of this article was to describe a novel curcumin containing a nanomicelle formulation using a polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol (PVCL-PVA-PEG) graft copolymer. Nanomicelle curcumin was formulated and optimized and then further evaluated for in vitro cytotoxicity/in vivo ocular irritation, in vitro cellular uptake/in vivo corneal permeation, and in vitro antioxidant activity/in vivo anti-inflammatory efficacy. The solubility, chemical stability, and antioxidant activity were greatly improved after the encapsulation of the PVCL-PVA-PEG nanomicelles. The nanomicelle curcumin ophthalmic solution was simple to prepare and the nanomicelles are stable to the storage conditions, and it had good cellular tolerance. Nanomicelle curcumin also had excellent ocular tolerance in rabbits. The use of nanomicelles significantly improved in vitro cellular uptake and in vivo corneal permeation as well as improved anti-inflammatory efficacy when compared with a free curcumin solution. These findings indicate that nanomicelles could be promising topical delivery systems for the ocular administration of curcumin.

High energy storage density over a broad temperature range in sodium bismuth titanate-based lead-free ceramics.

PubMed

Yang, Haibo; Yan, Fei; Lin, Ying; Wang, Tong; Wang, Fen

2017-08-18

A series of (1-x)Bi 0.48 La 0.02 Na 0.48 Li 0.02 Ti 0.98 Zr 0.02 O 3 -xNa 0.73 Bi 0.09 NbO 3 ((1-x)LLBNTZ-xNBN) (x = 0-0.14) ceramics were designed and fabricated using the conventional solid-state sintering method. The phase structure, microstructure, dielectric, ferroelectric and energy storage properties of the ceramics were systematically investigated. The results indicate that the addition of Na 0.73 Bi 0.09 NbO 3 (NBN) could decrease the remnant polarization (P r ) and improve the temperature stability of dielectric constant obviously. The working temperature range satisfying TCC 150  °C  ≤±15% of this work spans over 400 °C with the compositions of x ≥ 0.06. The maximum energy storage density can be obtained for the sample with x = 0.10 at room temperature, with an energy storage density of 2.04 J/cm 3 at 178 kV/cm. In addition, the (1-x)LLBNTZ-xNBN ceramics exhibit excellent energy storage properties over a wide temperature range from room temperature to 90 °C. The values of energy storage density and energy storage efficiency is 0.91 J/cm 3 and 79.51%, respectively, for the 0.90LLBNTZ-0.10NBN ceramic at the condition of 100 kV/cm and 90 °C. It can be concluded that the (1-x)LLBNTZ-xNBN ceramics are promising lead-free candidate materials for energy storage devices over a broad temperature range.

Ford/BASF/UM Activities in Support of the Hydrogen Storage Engineering Center of Excellence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veenstra, Mike; Purewal, Justin; Xu, Chunchuan

Widespread adoption of hydrogen as a vehicular fuel depends critically on the development of low-cost, on-board hydrogen storage technologies capable of achieving high energy densities and fast kinetics for hydrogen uptake and release. As present-day technologies -- which rely on physical storage methods such as compressed hydrogen -- are incapable of attaining established Department of Energy (DOE) targets, development of materials-based approaches for storing hydrogen have garnered increasing attention. Material-based storage technologies have potential to store hydrogen beyond twice the density of liquid hydrogen. To hasten development of these ‘hydride’ materials, the DOE previously established three centers of excellence formore » materials storage R&D associated with the key classes of materials: metal hydrides, chemical hydrogen, and adsorbents. While these centers made progress in identifying new storage materials, the challenges associated with the engineering of the system around a candidate storage material are in need of further advancement. In 2009 the DOE established the Hydrogen Storage Engineering Center of Excellence with the objective of developing innovative engineering concepts for materials-based hydrogen storage systems. As a partner in the Hydrogen Storage Engineering Center of Excellence, the Ford-UM-BASF team conducted a multi-faceted research program that addresses key engineering challenges associated with the development of materials-based hydrogen storage systems. First, we developed a novel framework that allowed for a material-based hydrogen storage system to be modeled and operated within a virtual fuel cell vehicle. This effort resulted in the ability to assess dynamic operating parameters and interactions between the storage system and fuel cell power plant, including the evaluation of performance throughout various drive cycles. Second, we engaged in cost modeling of various incarnations of the storage systems. This analysis revealed cost gaps and opportunities that identified a storage system that was lower cost than a 700 bar compressed system. Finally, we led the HSECoE efforts devoted to characterizing and enhancing metal organic framework (MOF) storage materials. This report serves as a final documentation of the Ford-UM-BASF project contributions to the HSECoE during the 6-year timeframe of the Center. The activities of the HSECoE have impacted the broader goals of the DOE-EERE and USDRIVE, leading to improved understanding in the engineering of materials-based hydrogen storage systems. This knowledge is a prerequisite to the development of a commercially-viable hydrogen storage system.« less

3D inverse-opal structured Li4Ti5O12 Anode for fast Li-Ion storage capabilities

NASA Astrophysics Data System (ADS)

Kim, Dahye; Quang, Nguyen Duc; Hien, Truong Thi; Chinh, Nguyen Duc; Kim, Chunjoong; Kim, Dojin

2017-11-01

Since the demand for high power Li-ion batteries (LIBs) is increasing, spinel-structured lithium titanate, Li4Ti5O12 (LTO), as the anode material has attracted great attention because of its excellent cycle retention, good thermal stability, high rate capability, and so on. However, LTO shows relatively low conductivity due to empty 3 d orbital of Ti4+ state. Nanoscale architectures can shorten electron conduction path, thus such low electronic conductivity can be overcome while Li+ can be easily accessed due to large surface area. Herein, three dimensional bicontinuous LTO electrodes were prepared via close-packed self-assembly with polystyrene (PS) spheres followed by removal of them, which leads to no blockage of Li+ ion transportation pathways as well as fast electron conduction. 3D bicontinuous LTO electrodes showed high-rate lithium storage capability (103 mAh/g at 20 C), which is promising as the power sources that require rapid electrochemical response.[Figure not available: see fulltext.

Shape-Tailorable Graphene-Based Ultra-High-Rate Supercapacitor for Wearable Electronics.

PubMed

Xie, Binghe; Yang, Cheng; Zhang, Zhexu; Zou, Peichao; Lin, Ziyin; Shi, Gaoquan; Yang, Quanhong; Kang, Feiyu; Wong, Ching-Ping

2015-06-23

With the bloom of wearable electronics, it is becoming necessary to develop energy storage units, e.g., supercapacitors that can be arbitrarily tailored at the device level. Although gel electrolytes have been applied in supercapacitors for decades, no report has studied the shape-tailorable capability of a supercapacitor, for instance, where the device still works after being cut. Here we report a tailorable gel-based supercapacitor with symmetric electrodes prepared by combining electrochemically reduced graphene oxide deposited on a nickel nanocone array current collector with a unique packaging method. This supercapacitor with good flexibility and consistency showed excellent rate performance, cycling stability, and mechanical properties. As a demonstration, these tailorable supercapacitors connected in series can be used to drive small gadgets, e.g., a light-emitting diode (LED) and a minimotor propeller. As simple as it is (electrochemical deposition, stencil printing, etc.), this technique can be used in wearable electronics and miniaturized device applications that require arbitrarily shaped energy storage units.

Giant energy density and high efficiency achieved in bismuth ferrite-based film capacitors via domain engineering.

PubMed

Pan, Hao; Ma, Jing; Ma, Ji; Zhang, Qinghua; Liu, Xiaozhi; Guan, Bo; Gu, Lin; Zhang, Xin; Zhang, Yu-Jun; Li, Liangliang; Shen, Yang; Lin, Yuan-Hua; Nan, Ce-Wen

2018-05-08

Developing high-performance film dielectrics for capacitive energy storage has been a great challenge for modern electrical devices. Despite good results obtained in lead titanate-based dielectrics, lead-free alternatives are strongly desirable due to environmental concerns. Here we demonstrate that giant energy densities of ~70 J cm -3 , together with high efficiency as well as excellent cycling and thermal stability, can be achieved in lead-free bismuth ferrite-strontium titanate solid-solution films through domain engineering. It is revealed that the incorporation of strontium titanate transforms the ferroelectric micro-domains of bismuth ferrite into highly-dynamic polar nano-regions, resulting in a ferroelectric to relaxor-ferroelectric transition with concurrently improved energy density and efficiency. Additionally, the introduction of strontium titanate greatly improves the electrical insulation and breakdown strength of the films by suppressing the formation of oxygen vacancies. This work opens up a feasible and propagable route, i.e., domain engineering, to systematically develop new lead-free dielectrics for energy storage.

Surface engineered porous silicon for stable, high performance electrochemical supercapacitors

PubMed Central

Oakes, Landon; Westover, Andrew; Mares, Jeremy W.; Chatterjee, Shahana; Erwin, William R.; Bardhan, Rizia; Weiss, Sharon M.; Pint, Cary L.

2013-01-01

Silicon materials remain unused for supercapacitors due to extreme reactivity of silicon with electrolytes. However, doped silicon materials boast a low mass density, excellent conductivity, a controllably etched nanoporous structure, and combined earth abundance and technological presence appealing to diverse energy storage frameworks. Here, we demonstrate a universal route to transform porous silicon (P-Si) into stable electrodes for electrochemical devices through growth of an ultra-thin, conformal graphene coating on the P-Si surface. This graphene coating simultaneously passivates surface charge traps and provides an ideal electrode-electrolyte electrochemical interface. This leads to 10–40X improvement in energy density, and a 2X wider electrochemical window compared to identically-structured unpassivated P-Si. This work demonstrates a technique generalizable to mesoporous and nanoporous materials that decouples the engineering of electrode structure and electrochemical surface stability to engineer performance in electrochemical environments. Specifically, we demonstrate P-Si as a promising new platform for grid-scale and integrated electrochemical energy storage. PMID:24145684

Surface engineered porous silicon for stable, high performance electrochemical supercapacitors.

PubMed

Oakes, Landon; Westover, Andrew; Mares, Jeremy W; Chatterjee, Shahana; Erwin, William R; Bardhan, Rizia; Weiss, Sharon M; Pint, Cary L

2013-10-22

Silicon materials remain unused for supercapacitors due to extreme reactivity of silicon with electrolytes. However, doped silicon materials boast a low mass density, excellent conductivity, a controllably etched nanoporous structure, and combined earth abundance and technological presence appealing to diverse energy storage frameworks. Here, we demonstrate a universal route to transform porous silicon (P-Si) into stable electrodes for electrochemical devices through growth of an ultra-thin, conformal graphene coating on the P-Si surface. This graphene coating simultaneously passivates surface charge traps and provides an ideal electrode-electrolyte electrochemical interface. This leads to 10-40X improvement in energy density, and a 2X wider electrochemical window compared to identically-structured unpassivated P-Si. This work demonstrates a technique generalizable to mesoporous and nanoporous materials that decouples the engineering of electrode structure and electrochemical surface stability to engineer performance in electrochemical environments. Specifically, we demonstrate P-Si as a promising new platform for grid-scale and integrated electrochemical energy storage.

Surface engineered porous silicon for stable, high performance electrochemical supercapacitors

NASA Astrophysics Data System (ADS)

Oakes, Landon; Westover, Andrew; Mares, Jeremy W.; Chatterjee, Shahana; Erwin, William R.; Bardhan, Rizia; Weiss, Sharon M.; Pint, Cary L.

2013-10-01

Silicon materials remain unused for supercapacitors due to extreme reactivity of silicon with electrolytes. However, doped silicon materials boast a low mass density, excellent conductivity, a controllably etched nanoporous structure, and combined earth abundance and technological presence appealing to diverse energy storage frameworks. Here, we demonstrate a universal route to transform porous silicon (P-Si) into stable electrodes for electrochemical devices through growth of an ultra-thin, conformal graphene coating on the P-Si surface. This graphene coating simultaneously passivates surface charge traps and provides an ideal electrode-electrolyte electrochemical interface. This leads to 10-40X improvement in energy density, and a 2X wider electrochemical window compared to identically-structured unpassivated P-Si. This work demonstrates a technique generalizable to mesoporous and nanoporous materials that decouples the engineering of electrode structure and electrochemical surface stability to engineer performance in electrochemical environments. Specifically, we demonstrate P-Si as a promising new platform for grid-scale and integrated electrochemical energy storage.

Nitrogen-doped biomass-based ultra-thin carbon nanosheets with interconnected framework for High-Performance Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Guo, Shasha; Chen, Yaxin; Shi, Liluo; Dong, Yue; Ma, Jing; Chen, Xiaohong; Song, Huaihe

2018-04-01

In this paper, a low-cost and environmental friendly synthesis strategy is proposed to fabricate nitrogen-doped biomass-based ultra-thin carbon nanosheets (N-CNS) with interconnected framework by using soybean milk as the carbon precursor and sodium chloride as the template. The interconnected porous nanosheet structure is beneficial for lithium ion transportation, and the defects introduced by pyridine nitrogen doping are favorable for lithium storage. When used as the anodes for lithium-ion batteries, the N-CNS electrode shows a high initial reversible specific capacity of 1334 mAh g-1 at 50 mA g-1, excellent rate performance (1212, 555 and 336 mAh g-1 at 0.05, 0.5 and 2 A g-1, respectively) and good cycling stability (355 mAh g-1 at 1 A g-1 after 1000 cycles). Furthermore, this study demonstrates the prospects of biomass and soybean milk, as the potential anode for the application of electrochemical energy storage devices.

A flexible ligand-based wavy layered metal-organic framework for lithium-ion storage.

PubMed

An, Tiance; Wang, Yuhang; Tang, Jing; Wang, Yang; Zhang, Lijuan; Zheng, Gengfeng

2015-05-01

A substantial challenge for direct utilization of metal-organic frameworks (MOFs) as lithium-ion battery anodes is to maintain the rigid MOF structure during lithiation/delithiation cycles. In this work, we developed a flexible, wavy layered nickel-based MOF (C20H24Cl2N8Ni, designated as Ni-Me4bpz) by a solvothermal approach of 3,3',5,5'-tetramethyl-4,4'-bipyrazole (H2Me4bpz) with nickel(II) chloride hexahydrate. The obtained MOF materials (Ni-Me4bpz) with metal azolate coordination mode provide 2-dimensional layered structure for Li(+) intercalation/extraction, and the H2Me4bpz ligands allow for flexible rotation feature and structural stability. Lithium-ion battery anodes made of the Ni-Me4bpz material demonstrate excellent specific capacity and cycling performance, and the crystal structure is well preserved after the electrochemical tests, suggesting the potential of developing flexible layered MOFs for efficient and stable electrochemical storage. Copyright © 2015 Elsevier Inc. All rights reserved.

Low temperature plasma synthesis of mesoporous Fe3O4 nanorods grafted on reduced graphene oxide for high performance lithium storage.

PubMed

Zhou, Quan; Zhao, Zongbin; Wang, Zhiyu; Dong, Yanfeng; Wang, Xuzhen; Gogotsi, Yury; Qiu, Jieshan

2014-02-21

Transition metal oxide coupling with carbon is an effective method for improving electrical conductivity of battery electrodes and avoiding the degradation of their lithium storage capability due to large volume expansion/contraction and severe particle aggregation during the lithium insertion and desertion process. In our present work, we develop an effective approach to fabricate the nanocomposites of porous rod-shaped Fe3O4 anchored on reduced graphene oxide (Fe3O4/rGO) by controlling the in situ nucleation and growth of β-FeOOH onto the graphene oxide (β-FeOOH/GO) and followed by dielectric barrier discharge (DBD) hydrogen plasma treatment. Such well-designed hierarchical nanostructures are beneficial for maximum utilization of electrochemically active matter in lithium ion batteries and display superior Li uptake with high reversible capacity, good rate capability, and excellent stability, maintaining 890 mA h g(-1) capacity over 100 cycles at a current density of 500 mA g(-1).

Synergetic interface between NiO/Ni3S2 nanosheets and carbon nanofiber as binder-free anode for highly reversible lithium storage

NASA Astrophysics Data System (ADS)

Jiang, Jialin; Ma, Chao; Yang, Yinbo; Ding, Jingjing; Ji, Hongmei; Shi, Shaojun; Yang, Gang

2018-05-01

A novel heterostructure of NiO/Ni3S2 nanoflake is synthesized and composited with carbon nanofibers (CNF) membrane. NiO/Ni3S2 nanoflakes are homogeneously dispersed in CNF network, herein, NiO/Ni3S2 like leaf and CNF like branch. Carbon nanofibers network efficiently prevents the pulverization and buffers the volume changes of NiO/Ni3S2, meanwhile, NiO/Ni3S2 nanoflakes through the conductive channels of carbon nanofibers own improved Li+ diffusion ability and structural stability. The capacity of NiO/Ni3S2/CNF reaches to 519.2 mA g-1 after 200 cycles at the current density of 0.5 A g-1 while NiO/Ni3S2 fades to 71 mAh g-1 after 40 cycles. Owing to the synergetic structure, the resultant binder-free electrode NiO/Ni3S2/carbon nanofibers shows an excellent reversible lithium storage capability.

Compton backscattered collimated x-ray source

DOEpatents

Ruth, R.D.; Huang, Z.

1998-10-20

A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

Compton backscattered collimated x-ray source

DOEpatents

Ruth, Ronald D.; Huang, Zhirong

1998-01-01

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

Compton backscattered collmated X-ray source

DOEpatents

Ruth, Ronald D.; Huang, Zhirong

2000-01-01

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

Amorphous and Crystalline Vanadium Oxides as High-Energy and High-Power Cathodes for Three-Dimensional Thin-Film Lithium Ion Batteries.

PubMed

Mattelaer, Felix; Geryl, Kobe; Rampelberg, Geert; Dendooven, Jolien; Detavernier, Christophe

2017-04-19

Flexible wearable electronics and on-chip energy storage for wireless sensors drive rechargeable batteries toward thin-film lithium ion batteries. To enable more charge storage on a given surface, higher energy density materials are required, while faster energy storage and release can be obtained by going to thinner films. Vanadium oxides have been examined as cathodes in classical and thin-film lithium ion batteries for decades, but amorphous vanadium oxide thin films have been mostly discarded. Here, we investigate the use of atomic layer deposition, which enables electrode deposition on complex three-dimensional (3D) battery architectures, to obtain both amorphous and crystalline VO 2 and V 2 O 5 , and we evaluate their thin-film cathode performance. Very high volumetric capacities are found, alongside excellent kinetics and good cycling stability. Better kinetics and higher volumetric capacities were observed for the amorphous vanadium oxides compared to their crystalline counterparts. The conformal deposition of these vanadium oxides on silicon micropillar structures is demonstrated. This study shows the promising potential of these atomic layer deposited vanadium oxides as cathodes for 3D all-solid-state thin-film lithium ion batteries.

Three dimensional graphene based materials: Synthesis and applications from energy storage and conversion to electrochemical sensor and environmental remediation.

PubMed

Wang, Hou; Yuan, Xingzhong; Zeng, Guangming; Wu, Yan; Liu, Yang; Jiang, Qian; Gu, Shansi

2015-07-01

With superior electrical/thermal conductivities and mechanical properties, two dimensional (2D) graphene has become one of the most intensively explored carbon allotropes in materials science. To exploit the inherent properties fully, 2D graphene sheets are often fabricated or assembled into functional architectures (e.g. hydrogels, aerogels) with desired three dimensional (3D) interconnected porous microstructures. The 3D graphene based materials show many excellent characteristics including increased active material per projected area, accessible mass transport or storage, electro/thermo conductivity, chemical/electrochemical stability and flexibility. It has paved the way for practical requirements in electronics, adsorption as well as catalysis related system. This review shows an extensive overview of the main principles and the recent synthetic technologies about fabricating various innovative 3D graphene based materials. Subsequently, recent progresses in electrochemical energy devices (lithium/lithium ion batteries, supercapacitors, fuel cells and solar cells) and hydrogen energy generation/storage are explicitly discussed. The up to date advances for pollutants detection and environmental remediation are also reviewed. Finally, challenges and outlooks in materials development for energy and environment are suggested. Copyright © 2015 Elsevier B.V. All rights reserved.

High-Level Heteroatom Doped Two-Dimensional Carbon Architectures for Highly Efficient Lithium-Ion Storage.

PubMed

Wang, Zhijie; Wang, Yanyan; Wang, Wenhui; Yu, Xiaoliang; Lv, Wei; Xiang, Bin; He, Yan-Bing

2018-01-01

In this work, high-level heteroatom doped two-dimensional hierarchical carbon architectures (H-2D-HCA) are developed for highly efficient Li-ion storage applications. The achieved H-2D-HCA possesses a hierarchical 2D morphology consisting of tiny carbon nanosheets vertically grown on carbon nanoplates and containing a hierarchical porosity with multiscale pore size. More importantly, the H-2D-HCA shows abundant heteroatom functionality, with sulfur (S) doping of 0.9% and nitrogen (N) doping of as high as 15.5%, in which the electrochemically active N accounts for 84% of total N heteroatoms. In addition, the H-2D-HCA also has an expanded interlayer distance of 0.368 nm. When used as lithium-ion battery anodes, it shows excellent Li-ion storage performance. Even at a high current density of 5 A g -1 , it still delivers a high discharge capacity of 329 mA h g -1 after 1,000 cycles. First principle calculations verifies that such unique microstructure characteristics and high-level heteroatom doping nature can enhance Li adsorption stability, electronic conductivity and Li diffusion mobility of carbon nanomaterials. Therefore, the H-2D-HCA could be promising candidates for next-generation LIB anodes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qi, Yuruo; Mu, Linqin; Zhao, Junmei

Na-ion batteries are becoming increasingly attractive as a low cost energy storage device. Sodium vanadium fluorophosphates have been studied extensively recently due to their high storage capacity and high discharge voltage. Shape and size often have a crucial influence over the properties. The controlling synthesis of nanoparticles with special microstructures is significant, which becomes a challenging issue and has drawn considerable attention. In this study, Na 3(VPO 4) 2F 3 nanoflowers have been synthesized via a pH-regulative low-temperature (120 °C) hydro-thermal route. In particular, it is a green route without any organic compounds involved. The hydro-thermal reaction time for themore » formation of Na 3(VPO 4) 2F 3 nanoflowers has also been investigated. A weak acid environment (pH = 2.60) with the possible presence of hydrogen fluoride molecules is necessary for the formation of the desired nanoflower microstructures. Moreover, compared to the nanoparticles obtained by Na 2HPO 4·12H 2O, the as-synthesized Na 3(VPO 4) 2F 3 nanoflowers showed an excellent Na-storage performance in terms of superior cycle stability, even without any further carbon coating or high-temperature treatment.« less

Bottom-up synthesis of nitrogen-doped graphene sheets for ultrafast lithium storage

NASA Astrophysics Data System (ADS)

Tian, Lei-Lei; Wei, Xian-Yong; Zhuang, Quan-Chao; Jiang, Chen-Hui; Wu, Chao; Ma, Guang-Yao; Zhao, Xing; Zong, Zhi-Min; Sun, Shi-Gang

2014-05-01

A facile bottom-up strategy was developed to fabricate nitrogen-doped graphene sheets (NGSs) from glucose using a sacrificial template synthesis method. Three main types of nitrogen dopants (pyridinic, pyrrolic and graphitic nitrogens) were introduced into the graphene lattice, and an inimitable microporous structure of NGS with a high specific surface area of 504 m2 g-1 was obtained. Particularly, with hybrid features of lithium ion batteries and Faradic capacitors at a low rate and features of Faradic capacitors at a high rate, the NGS presents a superior lithium storage performance. During electrochemical cycling, the NGS electrode afforded an enhanced reversible capacity of 832.4 mA h g-1 at 100 mA g-1 and an excellent cycling stability of 750.7 mA h g-1 after 108 discharge-charge cycles. Furthermore, an astonishing rate capability of 333 mA h g-1 at 10 000 mA g-1 and a high rate cycle performance of 280.6 mA h g-1 even after 1200 cycles were also achieved, highlighting the significance of nitrogen doping on the maximum utilization of graphene-based materials for advanced lithium storage.

High-Level Heteroatom Doped Two-Dimensional Carbon Architectures for Highly Efficient Lithium-Ion Storage

NASA Astrophysics Data System (ADS)

Wang, Zhijie; Wang, Yanyan; Wang, Wenhui; Yu, Xiaoliang; Lv, Wei; Xiang, Bin; He, Yan-Bing

2018-04-01

In this work, high-level heteroatom doped two-dimensional hierarchical carbon architectures (H-2D-HCA) are developed for highly efficient Li-ion storage applications. The achieved H-2D-HCA possesses a hierarchical 2D morphology consisting of tiny carbon nanosheets vertically grown on carbon nanoplates and containing a hierarchical porosity with multiscale pore size. More importantly, the H-2D-HCA shows abundant heteroatom functionality, with sulfur (S) doping of 0.9 % and nitrogen (N) doping of as high as 15.5 %, in which the electrochemically active N accounts for 84 % of total N heteroatoms. In addition, the H-2D-HCA also has an expanded interlayer distance of 0.368 nm. When used as lithium-ion battery anodes, it shows excellent Li-ion storage performance. Even at a high current density of 5 A g-1, it still delivered a high discharge capacity of 329 mA h g-1 after 1000 cycles. First principle calculations verified that such unique microstructure characteristics and high-level heteroatom doping nature can enhance Li adsorption stability, electronic conductivity and Li diffusion mobility of carbon nanomaterials. Therefore, the H-2D-HCA could be promising candidates for next-generation LIB anodes.

High areal capacity hybrid magnesium-lithium-ion battery with 99.9% Coulombic efficiency for large-scale energy storage.

PubMed

Yoo, Hyun Deog; Liang, Yanliang; Li, Yifei; Yao, Yan

2015-04-01

Hybrid magnesium-lithium-ion batteries (MLIBs) featuring dendrite-free deposition of Mg anode and Li-intercalation cathode are safe alternatives to Li-ion batteries for large-scale energy storage. Here we report for the first time the excellent stability of a high areal capacity MLIB cell and dendrite-free deposition behavior of Mg under high current density (2 mA cm(-2)). The hybrid cell showed no capacity loss for 100 cycles with Coulombic efficiency as high as 99.9%, whereas the control cell with a Li-metal anode only retained 30% of its original capacity with Coulombic efficiency well below 90%. The use of TiS2 as a cathode enabled the highest specific capacity and one of the best rate performances among reported MLIBs. Postmortem analysis of the cycled cells revealed dendrite-free Mg deposition on a Mg anode surface, while mossy Li dendrites were observed covering the Li surface and penetrated into separators in the Li cell. The energy density of a MLIB could be further improved by developing electrolytes with higher salt concentration and wider electrochemical window, leading to new opportunities for its application in large-scale energy storage.

Lamoka, a variety with excellent chip color out of cold storage and resistance to the golden potato cyst nematode

USDA-ARS?s Scientific Manuscript database

Lamoka is a white-skinned, white-fleshed potato cultivar variety notable for excellent chip color from cold storage, good yield, and resistance to both common scab and race Ro1 of the golden potato cyst nematode (Globodera rostochiensis). It was selected from a cross made at Cornell University in 1...

Aerosol-assisted chemical vapor deposition of V2O5 cathodes with high rate capabilities for magnesium-ion batteries

NASA Astrophysics Data System (ADS)

Drosos, Charalampos; Jia, Chenglin; Mathew, Shiny; Palgrave, Robert G.; Moss, Benjamin; Kafizas, Andreas; Vernardou, Dimitra

2018-04-01

The growth of orthorhombic vanadium pentoxide nanostructures was accomplished using an aerosol-assisted chemical vapor deposition process. These materials showed excellent electrochemical performance for magnesium-ion storage in an aqueous electrolyte; showing specific discharge capacities of up to 427 mAh g-1 with a capacity retention of 82% after 2000 scans under a high specific current of 5.9 A g-1. The high rate capability suggested good structural stability and high reversibility. We believe the development of low-cost and large-area coating methods, such as the technique used herein, will be essential for the upscalable fabrication of next-generation rechargeable battery technologies.

Urine stability studies for novel biomarkers of acute kidney injury.

PubMed

Parikh, Chirag R; Butrymowicz, Isabel; Yu, Angela; Chinchilli, Vernon M; Park, Meyeon; Hsu, Chi-Yuan; Reeves, W Brian; Devarajan, Prasad; Kimmel, Paul L; Siew, Edward D; Liu, Kathleen D

2014-04-01

The study of novel urinary biomarkers of acute kidney injury has expanded exponentially. Effective interpretation of data and meaningful comparisons between studies require awareness of factors that can adversely affect measurement. We examined how variations in short-term storage and processing might affect the measurement of urine biomarkers. Cross-sectional prospective. Hospitalized patients from 2 sites: Yale New Haven Hospital (n=50) and University of California, San Francisco Medical Center (n=36). We tested the impact of 3 urine processing conditions on these biomarkers: (1) centrifugation and storage at 4°C for 48 hours before freezing at -80°C, (2) centrifugation and storage at 25°C for 48 hours before freezing at -80°C, and (3) uncentrifuged samples immediately frozen at -80°C. Urine concentrations of 5 biomarkers: neutrophil gelatinase-associated lipocalin (NGAL), interleukin 18 (IL-18), kidney injury molecule 1 (KIM-1), liver-type fatty acid-binding protein (L-FABP), and cystatin C. We measured urine biomarkers by established enzyme-linked immunosorbent assay methods. Biomarker values were log-transformed, and agreement with a reference standard of immediate centrifugation and storage at -80°C was compared using concordance correlation coefficients (CCCs). Neither storing samples at 4°C for 48 hours nor centrifugation had a significant effect on measured levels, with CCCs higher than 0.9 for all biomarkers tested. For samples stored at 25°C for 48 hours, excellent CCC values (>0.9) also were noted between the test sample and the reference standard for NGAL, cystatin C, L-FABP and KIM-1. However, the CCC for IL-18 between samples stored at 25°C for 48 hours and the reference standard was 0.81 (95% CI, 0.66-0.96). No comparisons to fresh, unfrozen samples; no evaluation of the effect of protease inhibitors. All candidate markers tested using the specified assays showed high stability with both short-term storage at 4°C and without centrifugation prior to freezing. For optimal fidelity, urine for IL-18 measurement should not be stored at 25°C before long-term storage or analysis. Copyright © 2014 National Kidney Foundation, Inc. All rights reserved.

The influence of temperature induced phase transition on the energy storage density of anti-ferroelectric ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yi, Jinqiao; Zhang, Ling; Xie, Bing

2015-09-28

Anti-ferroelectric (AFE) composite ceramics of (Pb{sub 0.858}Ba{sub 0.1}La{sub 0.02}Y{sub 0.008})(Zr{sub 0.65}Sn{sub 0.3}Ti{sub 0.05})O{sub 3}-(Pb{sub 0.97}La{sub 0.02})(Zr{sub 0.9}Sn{sub 0.05} Ti{sub 0.05})O{sub 3} (PBLYZST-PLZST) were fabricated by the conventional solid-state sintering process (CS), the glass-aided sintering (GAS), and the spark plasma sintering (SPS), respectively. The influence of the temperature induced phase transition on the phase structure, hysteresis loops, and energy storage properties of the composite ceramics were investigated in detail. The measured results of X-ray diffraction demonstrate that the composite ceramics exhibit the perovskite phases and small amounts of non-functional pyrochlore phases. Compared with the CS process, the GAS and SPS processesmore » are proven more helpful to suppress the diffusion behaviors between the PBLYZST and PLZST phases according to the field emission scanning electron microscopy, thereby being able to improve the contribution of PBLYZST phase to the temperature stability of the orthogonal AFE phase. When the ambient temperature rises from 25 °C to 125 °C, CS and GAS samples have undergone a phase transition from orthorhombic AFE phase to tetragonal AFE phase, which results in a sharp decline in the energy storage density. However, the phase transition temperature of SPS samples is higher than 125 °C, and the energy storage density only slightly decreases due to the disorder of material microstructure caused by the high temperature. As a result, the SPS composite ceramics obtain a recoverable high energy storage density of 6.46 J/cm{sup 3} and the excellent temperature stability of the energy storage density of 1.16 × 10{sup −2} J/°C·cm{sup 3}, which is 1.29 × 10{sup −2} J/°C·cm{sup 3} lower than that of CS samples and about 0.43 times as that of GAS samples.« less

A MoO2 sheet as a promising electrode material: ultrafast Li-diffusion and astonishing Li-storage capacity

NASA Astrophysics Data System (ADS)

Zhou, Yungang; Geng, Cheng

2017-03-01

The potential of MoO2 crystal as an electrode material is reported, and nanostructural MoO2 systems, including nanoparticles, nanospheres, nanobelts and nanowires, were synthesized and proved to be advanced electrode materials. A two-dimensional (2D) geometric structure represents an extreme of surface-to-volume ratio, and thus is more suitable as an electrode material in general. Stimulated by the recent fabrication of 2D MoO2, we adopted an ab initio molecular dynamics simulation and density functional theory calculation to study the stability and electrochemical properties of a MoO2 sheet. Identified by a phonon dispersion curve and potential energy curve calculations, the MoO2 sheet proved to be dynamically and thermally stable. After lithiation, similar to most promising 2D structures, we found that a Li atom can strongly adsorb on a MoO2 sheet, and the lithiated MoO2 sheet presented excellent metallic properties. Note that, compared with most promising 2D structures, we unexpectedly revealed that the diffusion barrier of the Li atom on the MoO2 sheet was much lower and the storage capacity of the MoO2 sheet was much larger. The calculated energy barrier for the diffusion of Li on the MoO2 sheet was only 75 meV, and, due to multilayer adsorption, the theoretical capacity of the MoO2 sheet can reach up to 2513 mA h g-1. Benefiting from general properties, such as strong Li-binding and excellent conductivity, and unique phenomena, such as ultrafast diffusion capacity and astonishing storage capacity, we highlight a new promising electrode material for the Li-ion battery.

Cyanate ester-nanoparticle composites as multifunctional structural capacitors

NASA Astrophysics Data System (ADS)

De Leon, J. Eliseo

An important goal of engineering is to increase the energy density of electrical energy storage devices used to deliver power onboard mobile platforms. Equally important is the goal to reduce the overall mass of the vehicles transporting these devices to achieve increased fuel and cost efficiency. One approach to meeting both these objectives is to develop multifunctional systems that serve as both energy storage and load bearing structural devices. Multifunctional devices consist of constituents that individually perform a subset of the overall desired functions. However, the synergy achieved by the combination of each constituent's characteristics allows for system-level benefits that cannot be achieved by simply optimizing the separate subsystems. We investigated multifunctional systems consisting of light weight polymer matrix and high dielectric constant fillers to achieve these objectives. The monomer of bisphenol E cyanate ester exhibited excellent processing ability because of its low room temperature viscosity. Additionally, the fully cured thermoset demonstrated excellent thermal stability, specific strength and stiffness. Fillers, including multi-walled carbon nanotubes, nanometer scale barium titanate and nanometer scale calcium copper titanate, offer high dielectric constants that raised the effective dielectric constant of the polymer matrix composite. The combination of high epsilon'and high dielectric strength produce high energy density components exhibiting increased electrical energy storage. Mechanical (load bearing) improvements of the PMCs were attributed to covalently bonded nanometer and micrometer sized filler particles, as well as the continuous glass fiber, integrated into the resin systems which increased the structural characteristics of the cured composites. Breakdown voltage tests and dynamic mechanical analysis were employed to demonstrate that precise combinations of these constituents, under the proper processing conditions, can satisfy the needs presented by the aerospace industry and military forces.

Stability of thermostable alkaline protease from Bacillus licheniformis RP1 in commercial solid laundry detergent formulations.

PubMed

Sellami-Kamoun, Alya; Haddar, Anissa; Ali, Nedra El-Hadj; Ghorbel-Frikha, Basma; Kanoun, Safia; Nasri, Moncef

2008-01-01

The stability of crude extracellular protease produced by Bacillus licheniformis RP1, isolated from polluted water, in various solid laundry detergents was investigated. The enzyme had an optimum pH and temperature at pH 10.0-11.0 and 65-70 degrees C. Enzyme activity was inhibited by PMSF, suggesting that the preparation contains a serine-protease. The alkaline protease showed extreme stability towards non-ionic (5% Tween 20% and 5% Triton X-100) and anionic (0.5% SDS) surfactants, which retained 100% and above 73%, respectively, of its initial activity after preincubation 60 min at 40 degrees C. The RP1 protease showed excellent stability and compatibility with a wide range of commercial solid detergents at temperatures from 40 to 50 degrees C, suggesting its further application in detergent industry. The enzyme retained 95% of its initial activity with Ariel followed by Axion (94%) then Dixan (93.5%) after preincubation 60 min at 40 degrees C in the presence of 7 mg/ml of detergents. In the presence of Nadhif and New Det, the enzyme retained about 83.5% of the original activity. The effects of additives such as maltodextrin, sucrose and PEG 4000 on the stability of the enzyme during spray-drying and during subsequent storage in New Det detergent were also examined. All additives tested enhanced stability of the enzyme.

Unraveling protein stabilization mechanisms: vitrification and water replacement in a glass transition temperature controlled system.

PubMed

Grasmeijer, N; Stankovic, M; de Waard, H; Frijlink, H W; Hinrichs, W L J

2013-04-01

The aim of this study was to elucidate the role of the two main mechanisms used to explain the stabilization of proteins by sugar glasses during drying and subsequent storage: the vitrification and the water replacement theory. Although in literature protein stability is often attributed to either vitrification or water replacement, both mechanisms could play a role and they should be considered simultaneously. A model protein, alkaline phosphatase, was incorporated in either inulin or trehalose by spray drying. To study the storage stability at different glass transition temperatures, a buffer which acts as a plasticizer, ammediol, was incorporated in the sugar glasses. At low glass transition temperatures (<50°C), the enzymatic activity of the protein strongly decreased during storage at 60°C. Protein stability increased when the glass transition temperature was raised considerably above the storage temperature. This increased stability could be attributed to vitrification. A further increase of the glass transition temperature did not further improve stability. In conclusion, vitrification plays a dominant role in stabilization at glass transition temperatures up to 10 to 20°C above storage temperature, depending on whether trehalose or inulin is used. On the other hand, the water replacement mechanism predominantly determines stability at higher glass transition temperatures. Copyright © 2013 Elsevier B.V. All rights reserved.

Formulation, Optimization, Characterization, and Pharmacokinetics of Progesterone Intravenous Lipid Emulsion for Traumatic Brain Injury Therapy.

PubMed

Zhao, Jin; Yuan, Quan; Cai, WeiHui; Sun, Pan; Ding, LiYan; Jin, Fang

2017-07-01

Traumatic brain injury (TBI) is a major cause of mortality and disability throughout the world. Progesterone (PROG) plays an important role in neurologic treatment. The aim of this study was to develop a progesterone formulation with good physical and chemical stability. Progesterone intravenous lipid emulsion (PILE) was prepared based on one-factor-at-a-time experiments and orthogonal design. The optimal PILE was evaluated for mean particle size, particle size distribution, zeta potential, morphology, pH, osmolarity, entrapment efficiency, storage stability, and pharmacokinetics in ICR mice compared with the commercial progesterone products. The droplets of PILE had the smallest possible diameters of 218.0 ± 1.8 nm and adequate zeta potential of -41.1 ± 0.9 mV. The volume percentage of droplets exceeding 5 μm (PFAT 5 ) of PILE was 0.003 ± 0.0015% and much less than the specified standard. The TEM imaging proved that emulsion droplets had a smooth spherical appearance. Chemically and physically stable PILE was obtained with excellent entrapment efficiency that was up to 95.23%, with suitable pH at 7.15 ± 0.01 and osmolarity at 301.3 ± 1.2 mOsmol/l. Storage stability tests indicated that the emulsion was stable long term under ambient temperature conditions. Animal studies demonstrated that the emulsion was more effective with the higher progesterone concentration in the brain compared with commercial products. Therefore, the optimized PILE would offer great promise as a means of progesterone delivery for TBI therapy.

Stability of Chronic Hepatitis-Related Parameters in Serum Samples After Long-Term Storage.

PubMed

Yu, Rentao; Dan, Yunjie; Xiang, Xiaomei; Zhou, Yi; Kuang, Xuemei; Yang, Ge; Tang, Yulan; Liu, Mingdong; Kong, Weilong; Tan, Wenting; Deng, Guohong

2017-06-01

Serum samples are widely used in clinical research, but a comprehensive research of the stability of parameters relevant to chronic hepatitis and the effect of a relatively long-term (up to 10 years) storage on the stability have rarely been studied. To investigate the stability of chronic hepatitis-related parameters in serum samples after long-term storage. The storage stability of common clinical parameters such as total bile acid (TBA), total bilirubin (TBIL), potassium, cholesterol, and protein parameters such as alanine aminotransferase (ALT), creatine kinase (CK), γ-glutamyltransferase (GGT), albumin, high-density lipoprotein (HDL) and also hepatitis B virus (HBV) DNA, hepatitis C virus (HCV) RNA, hepatitis B surface antigen (HBsAg), and chemokine (C-X-C motif) ligand 10 (CXCL10) were tested in serum samples after storing at -20°C or -70°C for 1, 2, 3, 7, 8, and 10 years. Levels of TBA, TBIL, and protein parameters such as ALT, CK, GGT, HDL, and HBsAg decreased significantly, but levels of potassium and cholesterol increased significantly after long-term storage, whereas blood glucose and triglycerides were stable during storage. HBV DNA remained stable at -70°C but changed at -20°C, whereas HCV RNA was stable after 1-, 2-, and 3-year storage. CXCL10 was still detectable after 8-year storage. Low temperatures (-70°C/80°C) are necessary for storage of serum samples in chronic hepatitis B research after long-term storage.

Three-dimensional skeleton networks of graphene wrapped polyaniline nanofibers: an excellent structure for high-performance flexible solid-state supercapacitors

PubMed Central

Hu, Nantao; Zhang, Liling; Yang, Chao; Zhao, Jian; Yang, Zhi; Wei, Hao; Liao, Hanbin; Feng, Zhenxing; Fisher, Adrian; Zhang, Yafei; Xu, Zhichuan J.

2016-01-01

Thin, robust, lightweight, and flexible supercapacitors (SCs) have aroused growing attentions nowadays due to the rapid development of flexible electronics. Graphene-polyaniline (PANI) hybrids are attractive candidates for high performance SCs. In order to utilize them in real devices, it is necessary to improve the capacitance and the structure stability of PANI. Here we report a hierarchical three-dimensional structure, in which all of PANI nanofibers (NFs) are tightly wrapped inside reduced graphene oxide (rGO) nanosheet skeletons, for high-performance flexible SCs. The as-fabricated film electrodes with this unique structure showed a highest gravimetric specific capacitance of 921 F/g and volumetric capacitance of 391 F/cm3. The assembled solid-state SCs gave a high specific capacitance of 211 F/g (1 A/g), a high area capacitance of 0.9 F/cm2, and a competitive volumetric capacitance of 25.6 F/cm3. The SCs also exhibited outstanding rate capability (~75% retention at 20 A/g) as well as excellent cycling stability (100% retention at 10 A/g for 2000 cycles). Additionally, no structural failure and loss of performance were observed under the bending state. This structure design paves a new avenue for engineering rGO/PANI or other similar hybrids for high performance flexible energy storage devices. PMID:26795067

Three-dimensional skeleton networks of graphene wrapped polyaniline nanofibers: An excellent structure for high-performance flexible solid-state supercapacitors

DOE PAGES

Hu, Nantao; Zhang, Liling; Yang, Chao; ...

2016-01-22

Thin, robust, lightweight, and flexible supercapacitors (SCs) have aroused growing attentions nowadays due to the rapid development of flexible electronics. Graphene-polyaniline (PANI) hybrids are attractive candidates for high performance SCs. In order to utilize them in real devices, it is necessary to improve the capacitance and the structure stability of PANI. Here we report a hierarchical three-dimensional structure, in which all of PANI nanofibers (NFs) are tightly wrapped inside reduced graphene oxide (rGO) nanosheet skeletons, for high-performance flexible SCs. The as-fabricated film electrodes with this unique structure showed a highest gravimetric specific capacitance of 921 F/g and volumetric capacitance ofmore » 391 F/cm 3. The assembled solid-state SCs gave a high specific capacitance of 211 F/g (1 A/g), a high area capacitance of 0.9 F/cm 2, and a competitive volumetric capacitance of 25.6 F/cm 3. The SCs also exhibited outstanding rate capability (~75% retention at 20 A/g) as well as excellent cycling stability (100% retention at 10 A/g for 2000 cycles). Additionally, no structural failure and loss of performance were observed under the bending state. Lastly, this structure design paves a new avenue for engineering rGO/PANI or other similar hybrids for high performance flexible energy storage devices.« less

When Al-Doped Cobalt Sulfide Nanosheets Meet Nickel Nanotube Arrays: A Highly Efficient and Stable Cathode for Asymmetric Supercapacitors.

PubMed

Huang, Jun; Wei, Junchao; Xiao, Yingbo; Xu, Yazhou; Xiao, Yujuan; Wang, Ying; Tan, Licheng; Yuan, Kai; Chen, Yiwang

2018-03-27

Although cobalt sulfide is a promising electrode material for supercapacitors, its wide application is limited by relative poor electrochemical performance, low electrical conductivity, and inefficient nanostructure. Here, we demonstrated that the electrochemical activity of cobalt sulfide could be significantly improved by Al doping. We designed and fabricated hierarchical core-branch Al-doped cobalt sulfide nanosheets anchored on Ni nanotube arrays combined with carbon cloth (denoted as CC/H-Ni@Al-Co-S) as an excellent self-standing cathode for asymmetric supercapacitors (ASCs). The combination of structural and compositional advantages endows the CC/H-Ni@Al-Co-S electrode with superior electrochemical performance with high specific capacitance (1830 F g -1 /2434 F g -1 at 5 mV s -1 /1 A g -1 ) and excellent rate capability (57.2%/72.3% retention at 1000 mV s -1 /100 A g -1 ). The corresponding all-solid-state ASCs with CC/H-Ni@Al-Co-S and multilayer graphene/CNT film as cathode and anode, respectively, achieve a high energy density up to 65.7 W h kg -1 as well as superb cycling stability (90.6% retention after 10 000 cycles). Moreover, the ASCs also exhibit good flexibility and stability under different bending conditions. This work provides a general, effective route to prepare high-performance electrode materials for flexible all-solid-state energy storage devices.

3D hierarchical porous graphene aerogel with tunable meso-pores on graphene nanosheets for high-performance energy storage

PubMed Central

Ren, Long; Hui, K. N.; Hui, K. S.; Liu, Yundan; Qi, Xiang; Zhong, Jianxin; Du, Yi; Yang, Jianping

2015-01-01

New and novel 3D hierarchical porous graphene aerogels (HPGA) with uniform and tunable meso-pores (e.g., 21 and 53 nm) on graphene nanosheets (GNS) were prepared by a hydrothermal self-assembly process and an in-situ carbothermal reaction. The size and distribution of the meso-pores on the individual GNS were uniform and could be tuned by controlling the sizes of the Co3O4 NPs used in the hydrothermal reaction. This unique architecture of HPGA prevents the stacking of GNS and promises more electrochemically active sites that enhance the electrochemical storage level significantly. HPGA, as a lithium-ion battery anode, exhibited superior electrochemical performance, including a high reversible specific capacity of 1100 mAh/g at a current density of 0.1 A/g, outstanding cycling stability and excellent rate performance. Even at a large current density of 20 A/g, the reversible capacity was retained at 300 mAh/g, which is larger than that of most porous carbon-based anodes reported, suggesting it to be a promising candidate for energy storage. The proposed 3D HPGA is expected to provide an important platform that can promote the development of 3D topological porous systems in a range of energy storage and generation fields. PMID:26382852

Lithium rich cathode/graphite anode combination for lithium ion cells with high tolerance to near zero volt storage

NASA Astrophysics Data System (ADS)

Crompton, K. R.; Staub, J. W.; Hladky, M. P.; Landi, B. J.

2017-03-01

Management of reversible lithium is an advantageous approach to design lithium ion cells that are tolerant to near zero volt (NZV) storage under fixed resistive load towards highly controllable, enhanced user-inactive safety. Presently, the first cycle loss from a high energy density Li-rich HE5050 cathode is used to provide excess reversible lithium when paired with an appropriately capacity matched mesocarbon microbead (MCMB) anode. Cells utilizing 1.2 M LiPF6 3:7 v/v ethylene carbonate:ethyl methyl carbonate electrolyte and a lithium reference were used for 3-electrode testing. After conditioning, a fixed resistive load was applied to 3-electrode cells for 72 or 168-h during which the anode potential and electrode asymptotic potential (EAP) remained less than the copper dissolution potential. After multiple storage cycles (room temperature or 40 °C), the NZV coulombic efficiency (cell reversibility) exceeded 97% and the discharge capacity retention was >98%. Conventional 2-electrode HE5050/MCMB pouch cells stored at NZV or open circuit for 3 days had nearly identical rate capability (up to 5C) and discharge performance stability (for 500 cycles under a 30% depth of discharge low-earth-orbit regime). Thus, lithium ion cells with appropriately capacity matched HE5050/MCMB electrodes have excellent tolerance to prolonged NZV storage, which can lead to enhanced user-inactive safety.

Silver Nanoparticle Storage Stability in Aqueous and Biological Media

DTIC Science & Technology

2015-06-22

silver nanoparticle stability from the point of synthesis to the point of testing. The recommended conditions of water storage at 4°C protected from... silver nanoparticle formulation for fabrication. (Report No. 2014-73). 13 Métraux, G. S. & Mirkin, C. A. Rapid thermal synthesis of silver ...NAVAL MEDICAL RESEARCH UNIT SAN ANTONIO SILVER NANOPARTICLE STORAGE STABILITY IN AQUEOUS AND BIOLOGICAL MEDIA NATALIE A

Flexible in-plane microsupercapacitors with electrospun NiFe2O4 nanofibers for portable sensing applications.

PubMed

Li, La; Lou, Zheng; Han, Wei; Shen, Guozhen

2016-08-11

The development of wearable electronic devices in recent decades has brought new opportunities in the exploration of micro-supercapacitors as energy storage units. In this work, we report the fabrication of flexible NiFe2O4 nanofiber based in-plane micro-supercapacitors (MSCs), which can serve as energy storage receptors to drive a portable graphene pressure sensor. The obtained NiFe2O4 nanofiber electrodes exhibited a specific capacitance of 2.23 F cm(-3) at the scan rate of 100 mV s(-1), and excellent rate capability and robust cycling stability with a capacitance retention of 93.6% after 10 000 charge/discharge cycles. Moreover, the in-plane MSCs have superior flexibility and outstanding stability even after repetition of charge/discharge cycles during the convex and concave bending states. The MSCs offered a high energy density of 0.197 mWh cm(-3) and power density up to 2.07 W cm(-3). We also coupled the MSCs with a graphene pressure sensor as a micro-integrated system to implement it's pressure response function and used MATLAB to simulate this system behavior as well. The performance of the designed systems exhibited a stable pressure response, and the simulated results coincide well with the experimental data, demonstrating its feasibility in wearable electronic devices.

Heat-Stable Dry Powder Oxytocin Formulations for Delivery by Oral Inhalation.

PubMed

Fabio, Karine; Curley, Kieran; Guarneri, Joseph; Adamo, Benoit; Laurenzi, Brendan; Grant, Marshall; Offord, Robin; Kraft, Kelly; Leone-Bay, Andrea

2015-12-01

In this work, heat stable dry powders of oxytocin (OT) suitable for delivery by oral inhalation were prepared. The OT dry powders were prepared by spray drying using excipients chosen to promote OT stability including trehalose, isoleucine, polyvinylpyrrolidone, citrate (sodium citrate and citric acid), and zinc salts (zinc chloride and zinc citrate). Characterization by laser diffraction indicated that the OT dry powders had a median particle size of 2 μm, making them suitable for delivery by inhalation. Aerodynamic performance upon discharge from proprietary dry powder inhalers was evaluated by Andersen cascade impaction (ACI) and in an anatomically correct airway (ACA) model, and confirmed that the powders had excellent aerodynamic performance, with respirable fractions up to 77% (ACI, 30 L/min). Physicochemical characterization demonstrated that the powders were amorphous (X-ray diffraction) with high glass transition temperature (modulated differential scanning calorimetry, MDSC), suggesting the potential for stabilization of the OT in a glassy amorphous matrix. OT assay and impurity profile were conducted by reverse phase HPLC and liquid chromatography-mass spectrometry (LC-MS) after storage up to 32 weeks at 40°C/75%RH. Analysis demonstrated that OT dry powders containing a mixture of citrate and zinc salts retained more than 90% of initial assay after 32 weeks storage and showed significant reduction in dimers and trisulfide formation (up to threefold reduction compared to control).

Reduced graphene oxide-supported TiO2 fiber bundles with mesostructures as anode materials for lithium-ion batteries.

PubMed

Zhen, Mengmeng; Zhu, Xiaohe; Zhang, Xiao; Zhou, Zhen; Liu, Lu

2015-10-05

Although the synthesis of mesoporous materials is well established, the preparation of TiO2 fiber bundles with mesostructures, highly crystalline walls, and good thermal stability on the RGO nanosheets remains a challenge. Herein, a low-cost and environmentally friendly hydrothermal route for the synthesis of RGO nanosheet-supported anatase TiO2 fiber bundles with dense mesostructures is used. These mesostructured TiO2 -RGO materials are used for investigation of Li-ion insertion properties, which show a reversible capacity of 235 mA h g(-1) at 200 mA g(-1) and 150 mA h g(-1) at 1000 mA g(-1) after 1000 cycles. The higher specific surface area of the new mesostructures and high conductive substrate (RGO nanosheets) result in excellent lithium storage performance, high-rate performance, and strong cycling stability of the TiO2 -RGO composites. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilke, Rudeger H. T.; Baker, Amanda; Brown-Shaklee, Harlan

Here, alkali-free glasses, which exhibit high energy storage densities (~35 J/cc), present a unique opportunity to couple high temperature stability with high breakdown strength, and thus provide an avenue for capacitor applications with stringent temperature and power requirements. Realizing the potential of these materials in kilovolt class capacitors with >1 J/cc recoverable energy density requires novel packaging strategies that incorporate these extremely fragile dielectrics. In this paper, we demonstrate the feasibility of fabricating wound capacitors using 50-μm-thick glass. Two capacitors were fabricated from 2.8-m-long ribbons of thin (50 μm) glass wound into 125-140-mm-diameter spools. The capacitors exhibit a capacitance ofmore » 70-75 nF with loss tangents below 1%. The wound capacitors can operate up to 1 kV and show excellent temperature stability to 150 °C. By improving the end terminations, the self-resonance can be shifted to above 1 MHz, indicating that these materials may be useful for pulsed power applications with microsecond discharge times.« less

Improved Performance of Ionic Liquid Supercapacitors by using Tetracyanoborate Anions.

PubMed

Martins, Vitor L; Rennie, Anthony J R; Sanchez-Ramirez, Nedher; Torresi, Roberto M; Hall, Peter J

2018-02-01

Supercapacitors are energy storage devices designed to operate at higher power densities than conventional batteries, but their energy density is still too low for many applications. Efforts are made to design new electrolytes with wider electrochemical windows than aqueous or conventional organic electrolytes in order to increase energy density. Ionic liquids (ILs) with wide electrochemical stability windows are excellent candidates to be employed as supercapacitor electrolytes. ILs containing tetracyanoborate anions [B(CN) 4 ] offer wider electrochemical stability than conventional electrolytes and maintain a high ionic conductivity (6.9 mS cm -1 ). Herein, we report the use of ILs containing the [B(CN) 4 ] anion for such an application. They presented a high maximum operating voltage of 3.7 V, and two-electrode devices demonstrate high specific capacitances even when operating at relatively high rates (ca. 20 F g -1 @ 15 A g -1 ). This supercapacitor stored more energy and operated at a higher power at all rates studied when compared with cells using a commonly studied ILs.

A Triblock Copolymer Design Leads to Robust Hybrid Hydrogels for High-Performance Flexible Supercapacitors.

PubMed

Zhang, Guangzhao; Chen, Yunhua; Deng, Yonghong; Wang, Chaoyang

2017-10-18

We report here an intriguing hybrid conductive hydrogel as electrode for high-performance flexible supercapacitor. The key is using a rationally designed water-soluble ABA triblock copolymer (termed as IAOAI) containing a central poly(ethylene oxide) block (A) and terminal poly(acrylamide) (PAAm) block with aniline moieties randomly incorporated (B), which was synthesized by reversible additional fragment transfer polymerization. The subsequent copolymerization of aniline monomers with the terminated aniline moieties on the IAOAI polymer generates a three-dimensional cross-linking hybrid network. The hybrid hydrogel electrode demonstrates robust mechanical flexibility, remarkable electrochemical capacitance (919 F/g), and cyclic stability (90% capacitance retention after 1000 cycles). Moreover, the flexible supercapacitor based on this hybrid hydrogel electrode presents a large specific capacitance (187 F/g), superior to most reported conductive hydrogel-based supercapacitors. With the demonstrated additional favorable cyclic stability and excellent capacitive and rate performance, this hybrid hydrogel-based supercapacitor holds great promise for flexible energy-storage device.

Alkyl ammonium cation stabilized biocidal polyiodides with adaptable high density and low pressure.

PubMed

He, Chunlin; Parrish, Damon A; Shreeve, Jean'ne M

2014-05-26

The effective application of biocidal species requires building the active moiety into a molecular back bone that can be delivered and decomposed on demand under conditions of low pressure and prolonged high-temperature detonation. The goal is to destroy storage facilities and their contents while utilizing the biocidal products arising from the released energy to destroy any remaining harmful airborne agents. Decomposition of carefully selected iodine-rich compounds can produce large amounts of the very active biocides, hydroiodic acid (HI) and iodine (I2). Polyiodide anions, namely, I3(-), I5(-), which are excellent sources of such biocides, can be stabilized through interactions with large, symmetric cations, such as alkyl ammonium salts. We have designed and synthesized suitable compounds of adaptable high density up to 3.33 g cm(-3) that are low-pressure polyiodides with various alkyl ammonium cations, deliverable iodine contents of which range between 58.0-90.9%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultra-fast self-assembly and stabilization of reactive nanoparticles in reduced graphene oxide films

PubMed Central

Chen, Yanan; Egan, Garth C.; Wan, Jiayu; Zhu, Shuze; Jacob, Rohit Jiji; Zhou, Wenbo; Dai, Jiaqi; Wang, Yanbin; Danner, Valencia A.; Yao, Yonggang; Fu, Kun; Wang, Yibo; Bao, Wenzhong; Li, Teng; Zachariah, Michael R.; Hu, Liangbing

2016-01-01

Nanoparticles hosted in conductive matrices are ubiquitous in electrochemical energy storage, catalysis and energetic devices. However, agglomeration and surface oxidation remain as two major challenges towards their ultimate utility, especially for highly reactive materials. Here we report uniformly distributed nanoparticles with diameters around 10 nm can be self-assembled within a reduced graphene oxide matrix in 10 ms. Microsized particles in reduced graphene oxide are Joule heated to high temperature (∼1,700 K) and rapidly quenched to preserve the resultant nano-architecture. A possible formation mechanism is that microsized particles melt under high temperature, are separated by defects in reduced graphene oxide and self-assemble into nanoparticles on cooling. The ultra-fast manufacturing approach can be applied to a wide range of materials, including aluminium, silicon, tin and so on. One unique application of this technique is the stabilization of aluminium nanoparticles in reduced graphene oxide film, which we demonstrate to have excellent performance as a switchable energetic material. PMID:27515900

Encapsulating betalains from Opuntia ficus-indica fruits by ionic gelation: Pigment chemical stability during storage of beads.

PubMed

Otálora, María Carolina; Carriazo, José Gregorio; Iturriaga, Laura; Osorio, Coralia; Nazareno, Mónica Azucena

2016-07-01

Betalain encapsulation was performed by ionic gelation as a stabilization strategy for these natural pigments. Betalains were extracted from purple cactus fruits and encapsulated in calcium-alginate and in combination of calcium alginate and bovine serum albumin. Beads were characterised by scanning electron microscopy and thermal analysis using differential scanning calorimetry and thermogravimetry. Moisture sorption isotherms were determined. Bead morphology was affected by matrix composition. Pigments storage stability was evaluated at different equilibrium relative humidity and temperatures. Pigment composition of beads was determined by HPLC-MS-MS and degradation products were also analysed after storage; betalamic acid being the major one. Both types of matrices protected the encapsulated pigments, being their storage stability better at low relative humidity than that of the non-encapsulated control material. Antiradical activities of beads were proportional to remaining betalain contents. At high relative humidity, there was no protection and low storage stability was observed in the samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Facilitated charge transport in ternary interconnected electrodes for flexible supercapacitors with excellent power characteristics

NASA Astrophysics Data System (ADS)

Chen, Wanjun; He, Yongmin; Li, Xiaodong; Zhou, Jinyuan; Zhang, Zhenxing; Zhao, Changhui; Gong, Chengshi; Li, Shuankui; Pan, Xiaojun; Xie, Erqing

2013-11-01

Flexible and high performance supercapacitors are very critical in modern society. In order to develop the flexible supercapacitors with high power density, free-standing and flexible three-dimensional graphene/carbon nanotubes/MnO2 (3DG/CNTs/MnO2) composite electrodes with interconnected ternary 3D structures were fabricated, and the fast electron and ion transport channels were effectively constructed in the rationally designed electrodes. Consequently, the obtained 3DG/CNTs/MnO2 composite electrodes exhibit superior specific capacitance and rate capability compared to 3DG/MnO2 electrodes. Furthermore, the 3DG/CNTs/MnO2 based asymmetric supercapacitor demonstrates the maximum energy and power densities of 33.71 W h kg-1 and up to 22 727.3 W kg-1, respectively. Moreover, the asymmetric supercapacitor exhibits excellent cycling stability with 95.3% of the specific capacitance maintained after 1000 cycle tests. Our proposed synthesis strategy to construct the novel ternary 3D structured electrodes can be efficiently applied to other high performance energy storage/conversion systems.Flexible and high performance supercapacitors are very critical in modern society. In order to develop the flexible supercapacitors with high power density, free-standing and flexible three-dimensional graphene/carbon nanotubes/MnO2 (3DG/CNTs/MnO2) composite electrodes with interconnected ternary 3D structures were fabricated, and the fast electron and ion transport channels were effectively constructed in the rationally designed electrodes. Consequently, the obtained 3DG/CNTs/MnO2 composite electrodes exhibit superior specific capacitance and rate capability compared to 3DG/MnO2 electrodes. Furthermore, the 3DG/CNTs/MnO2 based asymmetric supercapacitor demonstrates the maximum energy and power densities of 33.71 W h kg-1 and up to 22 727.3 W kg-1, respectively. Moreover, the asymmetric supercapacitor exhibits excellent cycling stability with 95.3% of the specific capacitance maintained after 1000 cycle tests. Our proposed synthesis strategy to construct the novel ternary 3D structured electrodes can be efficiently applied to other high performance energy storage/conversion systems. Electronic supplementary information (ESI) available: Additional experimental details; calculations of the specific capacitances, and energy and power densities; additional SEM and optical images; XPS results; additional electrochemical results. See DOI: 10.1039/c3nr03923d

Electrical, Mechanical, and Capacity Percolation Leads to High-Performance MoS2/Nanotube Composite Lithium Ion Battery Electrodes.

PubMed

Liu, Yuping; He, Xiaoyun; Hanlon, Damien; Harvey, Andrew; Khan, Umar; Li, Yanguang; Coleman, Jonathan N

2016-06-28

Advances in lithium ion batteries would facilitate technological developments in areas from electrical vehicles to mobile communications. While two-dimensional systems like MoS2 are promising electrode materials due to their potentially high capacity, their poor rate capability and low cycle stability are severe handicaps. Here, we study the electrical, mechanical, and lithium storage properties of solution-processed MoS2/carbon nanotube anodes. Nanotube addition gives up to 10(10)-fold and 40-fold increases in electrical conductivity and mechanical toughness, respectively. The increased conductivity results in up to a 100× capacity enhancement to ∼1200 mAh/g (∼3000 mAh/cm(3)) at 0.1 A/g, while the improved toughness significantly boosts cycle stability. Composites with 20 wt % nanotubes combine high reversible capacity with excellent cycling stability (e.g., ∼950 mAh/g after 500 cycles at 2 A/g) and high rate capability (∼600 mAh/g at 20 A/g). The conductivity, toughness, and capacity scale with nanotube content according to percolation theory, while the stability increases sharply at the mechanical percolation threshold. We believe that the improvements in conductivity and toughness obtained after addition of nanotubes can be transferred to other electrode materials, such as silicon nanoparticles.

Engineering Polymer Nanocomoposite Aerogels for Energy Storage and Harvesting

NASA Astrophysics Data System (ADS)

Zheng, Qifeng

Various porous polymer nanocomposite aerogels were synthesized using an environmentally friendly freeze-drying process. These polymer nanocomposite aerogels exhibit ultralow densities, high porosities, high specific surface areas and high flexibility. The advantages of these polymer nanocomposites aerogels for energy storage and energy harvesting applications have been demonstrated. Flexible supercapacitors (SCs) are particularly attractive for energy storage applications due to their high power densities and long life cycles. A novel type of highly flexible and all-solid-state SCs using cellulose nanofibril (CNF)-reduced graphene oxide (RGO)-carbon nanotube (CNT) aerogels as electrodes was developed. Due to the porous structure of the CNF/RGO/CNT aerogel electrodes, and the excellent electrolyte absorption properties of the CNFs present in the electrodes, the resulting all-solid-state SCs exhibited excellent electrochemical performance, superior flexibility and cycle stability. To further increase the capacitances and energy densities, pseudocapacitive materials (i.e., MoO3) were incorporated to prepare the free-standing and highly flexible CNF-RGO-molybdenum oxynitride (MoOxNy) aerogel film electrode. Supercapacitors made with the CNF/RGO/MoOxNy aerogel electrodes exhibited outstanding specific capacitances and remarkable energy densities in different electrolytes while maintaining the high power densities and superior cycle stability. Flexible nanogenerators (NGs) that can harvest ubiquitous mechanical energy from ambient environments have attracted significant attention during the past decade. A novel, simple, cost-effective, and scalable technique was developed to fabricate high-performance flexible compact NGs using porous CNF-poly(dimethylsiloxane) (PDMS) aerogel film. Under external stress, the resulting NGs exhibited very stable and high output signals. We hypothesized that the remarkable electric outputs would not only be attributable to the intrinsic piezoelectric properties of the CNFs, but also to the mechanoradicals generated by the porous PDMS coated on the surface of the CNF aerogel film, which can lead to a change in the electric dipole moments and consequently generate electric outputs. A series of systematic studies were carried out to substantiate this new mechanism. These systematic studies have demonstrated that high-performance NGs can be made from porous mechanoradical-generating polymer films. The elucidation of the mechanisms for this family of porous mechanoradical-generating polymers will lead to a new class of energy harvesting materials and high-performance flexible energy generation devices.

Relationship between pyrite Stability and arsenic mobility during aquifer storage and recovery in southwest central Florida.

PubMed

Jones, Gregg W; Pichler, Thomas

2007-02-01

Elevated arsenic concentrations are common in water recovered from aquifer storage and recovery (ASR) systems in west-central Florida that store surface water. Investigations of the Suwannee Limestone of the Upper Floridan aquifer, the storage zone for ASR systems, have shown that arsenic is highest in pyrite in zones of high moldic porosity. Geochemical modeling was employed to examine pyrite stability in limestone during simulated injections of surface water into wells open only to the Suwannee Limestone with known mineralogy and water chemistry. The goal was to determine if aquifer redox conditions could be altered to the degree of pyrite instability. Increasing amounts of injection water were added to native storage-zone water, and resulting reaction paths were plotted on pyrite stability diagrams. Native storage-zone water plotted within the pyrite stability field, indicating that conditions were sufficiently reducing to allow for pyrite stability. Thus, arsenic is immobilized in pyrite, and its groundwater concentration should be low. This was corroborated by analysis of water samples, none of which had arsenic concentrations above 0.036 microg/L. During simulation, however, as injection/native storage-zone water ratios increased, conditions became less reducing and pyrite became unstable. The result would be release of arsenic from limestone into storage-zone water.

High-performance microsupercapacitors based on two-dimensional graphene/manganese dioxide/silver nanowire ternary hybrid film.

PubMed

Liu, Wenwen; Lu, Congxiang; Wang, Xingli; Tay, Roland Yingjie; Tay, Beng Kang

2015-02-24

Microsupercapacitors (MSCs), as one type of significant power source or energy storage unit in microelectronic devices, have attracted more and more attention. However, how to reasonably design electrode structures and exploit the active materials to endow the MSCs with excellent performances in a limited surface area still remains a challenge. Here, a reduced graphene oxide (RGO)/manganese dioxide (MnO2)/silver nanowire (AgNW) ternary hybrid film (RGMA ternary hybrid film) is successfully fabricated by a facile vacuum filtration and subsequent thermal reduction, and is used directly as a binder-free electrode for MSCs. Additionally, a flexible, transparent, all-solid state RMGA-MSC is also built, and its electrochemical performance in an ionic liquid gel electrolyte are investigated in depth. Notably, the RGMA-MSCs display superior electrochemical properties, including exceptionally high rate capability (up to 50000 mV·s(-1)), high frequency response (very short corresponding time constant τ0 = 0.14 ms), and excellent cycle stability (90.3% of the initial capacitance after 6000 cycles in ionic liquid gel electrolyte). Importantly, the electrochemical performance of RGMA-MSCs shows a strong dependence on the geometric parameters including the interspace between adjacent fingers and the width of the finger of MSCs. These encouraging results may not only provide important references for the design and fabrication of high-performance MSCs, but also make the RGMA ternary hybrid film promising for the next generation film lithium ion batteries and other energy storage devices.

Rational Design of Hierarchically Core-Shell Structured Ni3 S2 @NiMoO4 Nanowires for Electrochemical Energy Storage.

PubMed

Chen, Fangshuai; Ji, Shan; Liu, Quanbing; Wang, Hui; Liu, Hao; Brett, Dan J L; Wang, Guoxiu; Wang, Rongfang

2018-05-30

Rational design and controllable synthesis of nanostructured materials with unique microstructure and excellent electrochemical performance for energy storage are crucially desired. In this paper, a facile method is reported for general synthesis of hierarchically core-shell structured Ni 3 S 2 @NiMoO 4 nanowires (NWs) as a binder-free electrode for asymmetric supercapacitors. Due to the intimate contact between Ni 3 S 2 and NiMoO 4 , the hierarchical structured electrodes provide a promising unique structure for asymmetric supercapacitors. The as-prepared binder-free Ni 3 S 2 @NiMoO 4 electrode can significantly improve the electrical conductivity between Ni 3 S 2 and NiMoO 4 , and effectively avoid the aggregation of NiMoO 4 nanosheets, which provide more active space for storing charge. The Ni 3 S 2 @NiMoO 4 electrode presents a high areal capacity of 1327.3 µAh cm -2 and 67.8% retention of its initial capacity when current density increases from 2 to 40 mA cm -2 . In a two-electrode Ni 3 S 2 @NiMoO 4 //active carbon cell, the active materials deliver a high energy density of 121.5 Wh kg -1 at a power density of 2.285 kW kg -1 with excellent cycling stability. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

3D Interconnected and Multiwalled Carbon@MoS2 @Carbon Hollow Nanocables as Outstanding Anodes for Na-Ion Batteries.

PubMed

Wang, Yan; Qu, Qunting; Li, Guangchao; Gao, Tian; Qian, Feng; Shao, Jie; Liu, Weijie; Shi, Qiang; Zheng, Honghe

2016-11-01

Currently, the specific capacity and cycling performance of various MoS 2 /carbon-based anode materials for Na-ion storage are far from satisfactory due to the insufficient structural stability of the electrode, incomplete protection of MoS 2 by carbon, difficult access of electrolyte to the electrode interior, as well as inactivity of the adopted carbon matrix. To address these issues, this work presents the rational design and synthesis of 3D interconnected and hollow nanocables composed of multiwalled carbon@MoS 2 @carbon. In this architecture, (i) the 3D nanoweb-like structure brings about excellent mechanical property of the electrode, (ii) the ultrathin MoS 2 nanosheets are sandwiched between and doubly protected by two layers of porous carbon, (iii) the hollow structure of the primary nanofibers facilitates the access of electrolyte to the electrode interior, (iv) the porous and nitrogen-doping properties of the two carbon materials lead to synergistic Na-storage of carbon and MoS 2 . As a result, this hybrid material as the anode material of Na-ion battery exhibits fast charge-transfer reaction, high utilization efficiency, and ultrastability. Outstanding reversible capacity (1045 mAh g -1 ), excellent rate behavior (817 mAh g -1 at 7000 mA g -1 ), and good cycling performance (747 mAh g -1 after 200 cycles at 700 mA g -1 ) are obtained. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrothermal synthesis of nickel oxide nanosheets for lithium-ion batteries and supercapacitors with excellent performance.

PubMed

Mondal, Anjon Kumar; Su, Dawei; Wang, Ying; Chen, Shuangqiang; Wang, Guoxiu

2013-11-01

Nickel oxide nanosheets have been successfully synthesized by a facile ethylene glycol mediated hydrothermal method. The morphology and crystal structure of the nickel oxide nanosheets were characterized by X-ray diffraction, field-emission SEM, and TEM. When applied as electrode materials for lithium-ion batteries and supercapacitors, nickel oxide nanosheets exhibited a high, reversible lithium storage capacity of 1193 mA h g(-1) at a current density of 500 mA g(-1), an enhanced rate capability, and good cycling stability. Nickel oxide nanosheets also demonstrated a superior specific capacitance of 999 F g(-1) at a current density of 20 A g(-1) in supercapacitors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

N-doped amorphous carbon coated Fe3O4/SnO2 coaxial nanofibers as a binder-free self-supported electrode for lithium ion batteries.

PubMed

Xie, Wenhe; Li, Suyuan; Wang, Suiyan; Xue, Song; Liu, Zhengjiao; Jiang, Xinyu; He, Deyan

2014-11-26

N-doped amorphous carbon coated Fe3O4/SnO2 coaxial nanofibers were prepared via a facile approach. The core composite nanofibers were first made by electrospinning technology, then the shells were conformally coated using the chemical bath deposition and subsequent carbonization with polydopamine as a carbon source. When applied as a binder-free self-supported anode for lithium ion batteries, the coaxial nanofibers displayed an enhanced electrochemical storage capacity and excellent rate performance. The morphology of the interwoven nanofibers was maintained even after the rate cycle test. The superior electrochemical performance originates in the structural stability of the N-doped amorphous carbon shells formed by carbonizing polydopamine.

Spectroscopic analysis and the excellent reusability of sphere-capped ferrocene in the oxidation of glucose oxidase.

PubMed

Antepli, Esin; Sarı, Nurşen

2016-08-01

Sphere-capped ferrocene nanospheres with Schiff base spacers have been prepared using a template, and used as carriers to immobilize glucose oxidase (GOx). GOx immobilized on spheres with one C-spacer (APS-Fc) exhibited high binding affinity to the substrate, which was attributed to appropriate position for the GOx conformation. When glucose oxidase was immobilized with spacers of different lengths, it was found that storage stability decreased with increasing the length of the spacer. It has been found that nanospheres, including capped ferrocene, exhibit good performance as the immobilized supporters of GOx. (APS-EtFc-GOx) retain more than 10% of the initial activity after forty-two successive cycles, which is a remarkable result.

Synthesis of Pt/K2CO3/MgAlOx–reduced graphene oxide hybrids as promising NOx storage–reduction catalysts with superior catalytic performance

PubMed Central

Mei, Xueyi; Yan, Qinghua; Lu, Peng; Wang, Junya; Cui, Yuhan; Nie, Yu; Umar, Ahmad; Wang, Qiang

2017-01-01

Pt/K2CO3/MgAlOx–reduced graphene oxide (Pt/K/MgAlOx–rGO) hybrids were synthesized, characterized and tested as a promising NOx storage and reduction (NSR) catalyst. Mg–Al layered double hydroxides (LDHs) were grown on rGO via in situ hydrothermal crystallization. The structure and morphology of samples were thoroughly characterized using various techniques. Isothermal NOx adsorption tests indicated that MgAlOx–rGO hybrid exhibited better NOx trapping performance than MgAlOx, from 0.44 to 0.61 mmol · g−1, which can be attributed to the enhanced particle dispersion and stabilization. In addition, a series of MgAlOx–rGO loaded with 2 wt% Pt and different loadings (5, 10, 15, and 20 wt%) of K2CO3 (denoted as Pt/K/MgAlOx–rGO) were obtained by sequential impregnation. The influence of 5% H2O on the NOx storage capacity of MgAlOx–rGO loaded with 2 wt% Pt and 10% K2CO3 (2Pt/10 K/MgAlOx–rGO) catalyst was also evaluated. In all, the 2Pt/10 K/MgAlOx–rGO catalyst not only exhibited high thermal stability and NOx storage capacity of 1.12 mmol · g−1, but also possessed excellent H2O resistance and lean–rich cycling performance, with an overall 78.4% of NOx removal. This work provided a new scheme for the preparation of highly dispersed MgAlOx–rGO hybrid based NSR catalysts. PMID:28205630

EFFECTS OF STORAGE ON STABILITY AND PATHOGEN REDUCTION IN BIOSOLIDS

EPA Science Inventory

Storage can be an effective means of stabilizing small quantities of wastewater sludge. This paper summarizes the performance of two laboratory-scale sludge storage units and that of four full-scale tanks sampled at four treatment facilities in eastern Nebraska. The bench-scale u...

Impact of wind farms with energy storage on transient stability

NASA Astrophysics Data System (ADS)

Bowman, Douglas Allen

Today's energy infrastructure will need to rapidly expand in terms of reliability and flexibility due to aging infrastructure, changing energy market conditions, projected load increases, and system reliability requirements. Over the few decades, several states in the U.S. are now requiring an increase in wind penetration. These requirements will have impacts on grid reliability given the inherent intermittency of wind generation and much research has been completed on the impact of wind on grid reliability. Energy storage has been proposed as a tool to provide greater levels of reliability; however, little research has occurred in the area of wind with storage and its impact on stability given different possible scenarios. This thesis addresses the impact of wind farm penetration on transient stability when energy storage is added. The results show that battery energy storage located at the wind energy site can improve the stability response of the system.

Moisture content impacts the stability of DNA adsorbed onto gold microparticles.

PubMed

Smyth, Tyson J; Betker, Jamie; Wang, Wei; Anchordoquy, Thomas J

2011-11-01

Particle-mediated epidermal delivery (PMED) of small quantities of DNA (0.5-4.0 μg) has been reported to both induce an immune response and protect against disease in human subjects. In order for the PMED of DNA to be a viable technique for vaccination, the adsorbed DNA must be stable during shipping and storage. Here, we report that the storage stability of plasmid DNA adsorbed to 2-μm gold particles is strongly dependent on sample water content. Gold/DNA samples stored at 60°C and 6% relative humidity (RH) maintained supercoil content after 4-month storage, whereas storage at higher RHs facilitated degradation. Storage with desiccants had stabilizing effects on DNA similar to storage at 6% RH. However, storage with "indicating" Drierite and phosphorus pentoxide resulted in enhanced rates of DNA degradation. Copyright © 2011 Wiley-Liss, Inc.

Mercury stabilization in chemically bonded phosphate ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagh, Arun S.; Jeong, Seung-Young; Singh, Dileep

1997-07-01

We have investigated mercury stabilization in chemically bonded phosphate ceramic (CBPC) using four surrogate waste streams that represent U.S. Department of Energy (DOE) ash, soil, and two secondary waste streams resulting from the destruction of DOE`s high-organic wastes by the DETOX{sup SM} Wet Oxidation Process. Hg content in the waste streams was 0.1 to 0.5 wt.% (added as soluble salts). Sulfidation of Hg and its concurrent stabilization in the CBPC matrix yielded highly nonleachable waste forms. The Toxicity Characteristic Leaching Procedure showed that leaching levels were well below the U.S. Environmental Protection Agency`s regulatory limits. The American Nuclear Society`s ANSmore » 16.1 immersion test also gave very high leaching indices, indicating excellent retention of the contaminants. In particular, leaching levels of Hg in the ash waste form were below the measurement detection limit in neutral and alkaline water, negligibly low but measureable in the first 72 h of leaching in acid water, and below the detection limit after that. These studies indicate that the waste forms are stable in a wide range of chemical environments during storage. 9 refs., 5 tabs.« less

Cuttlebone-like V2O5 Nanofibre Scaffolds - Advances in Structuring Cellular Solids.

PubMed

Knöller, Andrea; Runčevski, Tomče; Dinnebier, Robert E; Bill, Joachim; Burghard, Zaklina

2017-02-20

The synthesis of ceramic materials combining high porosity and permeability with good mechanical stability is challenging, as optimising the latter requires compromises regarding the first two properties. Nonetheless, significant progress can be made in this direction by taking advantage of the structural design principles evolved by nature. Natural cellular solids achieve good mechanical stability via a defined hierarchical organisation of the building blocks they are composed of. Here, we report the first synthetic, ceramic-based scaffold whose architecture closely mimics that of cuttlebone -a structural biomaterial whose porosity exceeds that of most other natural cellular solids, whilst preserving an excellent mechanical strength. The nanostructured, single-component scaffold, obtained by ice-templated assembly of V 2 O 5 nanofibres, features a highly sophisticated and elaborate architecture of equally spaced lamellas, which are regularly connected by pillars as lamella support. It displays an unprecedented porosity of 99.8 %, complemented by an enhanced mechanical stability. This novel bioinspired, functional material not only displays mechanical characteristics similar to natural cuttlebone, but the multifunctionality of the V 2 O 5 nanofibres also renders possible applications, including catalysts, sensors and electrodes for energy storage.

Cuttlebone-like V2O5 Nanofibre Scaffolds - Advances in Structuring Cellular Solids

NASA Astrophysics Data System (ADS)

Knöller, Andrea; Runčevski, Tomče; Dinnebier, Robert E.; Bill, Joachim; Burghard, Zaklina

2017-02-01

The synthesis of ceramic materials combining high porosity and permeability with good mechanical stability is challenging, as optimising the latter requires compromises regarding the first two properties. Nonetheless, significant progress can be made in this direction by taking advantage of the structural design principles evolved by nature. Natural cellular solids achieve good mechanical stability via a defined hierarchical organisation of the building blocks they are composed of. Here, we report the first synthetic, ceramic-based scaffold whose architecture closely mimics that of cuttlebone -a structural biomaterial whose porosity exceeds that of most other natural cellular solids, whilst preserving an excellent mechanical strength. The nanostructured, single-component scaffold, obtained by ice-templated assembly of V2O5 nanofibres, features a highly sophisticated and elaborate architecture of equally spaced lamellas, which are regularly connected by pillars as lamella support. It displays an unprecedented porosity of 99.8 %, complemented by an enhanced mechanical stability. This novel bioinspired, functional material not only displays mechanical characteristics similar to natural cuttlebone, but the multifunctionality of the V2O5 nanofibres also renders possible applications, including catalysts, sensors and electrodes for energy storage.

Synthesis of novel laccase-biotitania biocatalysts for malachite green decolorization.

PubMed

Zhang, Xinying; Wang, Meiyin; Lin, Linlin; Xiao, Gao; Tang, Zhenping; Zhu, Xuefeng

2018-07-01

Biomimetic mineralization has emerged as a novel tool for generating excellent supports for enzyme stabilization. In this work, protamine was used to induce titanium (IV) bis(ammonium lactato) dihydroxide (Ti-BALDH) into titania nanoparticles. This biomimetic titanification process was adopted for laccase immobilization. Laccase-biotitania biocatalyst was prepared and the effect of different parameters (buffer solution, titania precursor concentration, protamine concentration, and enzyme loading) on the encapsulation efficiency and recovery of laccase were evaluated. Compared with free laccase, the thermal and pH stability of immobilized laccase were improved significantly. In addition, laccase loaded on titania was effective at enhancing its storage stability. After seven consecutive cycles, the immobilized laccase still retained 51% of its original activity. Finally, laccase-biotitania biocatalysts showed good performance on decolorization of malachite green (MG), which can be attributed to an adsorption and degradation effect. The intermediates of the MG degradation were identified by gas chromatography-mass spectrometry (GC-MS) analysis, and the most probable degradation pathway was proposed. This study provides deeper understanding of the laccase-biotitania particles as a fast biocatalyst for MG decolorization. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

A versatile strategy toward binary three-dimensional architectures based on engineering graphene aerogels with porous carbon fabrics for supercapacitors.

PubMed

Song, Wei-Li; Song, Kuo; Fan, Li-Zhen

2015-02-25

Graphene-based supercapacitors and related flexible devices have attracted great attention because of the increasing demands in the energy storage. As promising three-dimensional (3D) nanostructures in the supercapacitor electrodes, graphene-based aerogels have been paid dramatic attention recently, and numerous methods have been developed for enhancing their performance in energy storage. In this study, an exclusive strategy is presented toward directly in situ growing reduced graphene oxide (RGO) aerogels inside the 3D porous carbon fabrics for engineering the interfaces of the resulting binary 3D architectures. Such unique architectures have shown various advantages in the improvements of the nanostructures and chemical compositions, allowing them to possess much enhanced electrochemical properties (391, 229, and 195 F g(-1) at current densities of 0.1, 1, and 5 A g(-1), respectively) with excellent cycling stability in comparison with the neat RGO aerogels. The results of the performance in the flexible all-solid-state supercapacitors along with discussion on the related mechanisms in the electrochemical properties indicate the remaining issues and associated opportunities in the development of advanced energy storage devices. This strategy is relatively facile, versatile, and tunable, which highlights a unique platform for engineering various 3D porous structures in many fields.

Template-Free Synthesis of Sb2S3 Hollow Microspheres as Anode Materials for Lithium-Ion and Sodium-Ion Batteries

NASA Astrophysics Data System (ADS)

Xie, Jianjun; Liu, Li; Xia, Jing; Zhang, Yue; Li, Min; Ouyang, Yan; Nie, Su; Wang, Xianyou

2018-03-01

Hierarchical Sb2S3 hollow microspheres assembled by nanowires have been successfully synthesized by a simple and practical hydrothermal reaction. The possible formation process of this architecture was investigated by X-ray diffraction, focused-ion beam-scanning electron microscopy dual-beam system, and transmission electron microscopy. When used as the anode material for lithium-ion batteries, Sb2S3 hollow microspheres manifest excellent rate property and enhanced lithium-storage capability and can deliver a discharge capacity of 674 mAh g-1 at a current density of 200 mA g-1 after 50 cycles. Even at a high current density of 5000 mA g-1, a discharge capacity of 541 mAh g-1 is achieved. Sb2S3 hollow microspheres also display a prominent sodium-storage capacity and maintain a reversible discharge capacity of 384 mAh g-1 at a current density of 200 mA g-1 after 50 cycles. The remarkable lithium/sodium-storage property may be attributed to the synergetic effect of its nanometer size and three-dimensional hierarchical architecture, and the outstanding stability property is attributed to the sufficient interior void space, which can buffer the volume expansion. [Figure not available: see fulltext.

High-performance colossal permittivity materials of (Nb + Er) co-doped TiO2 for large capacitors and high-energy-density storage devices.

PubMed

Tse, Mei-Yan; Wei, Xianhua; Hao, Jianhua

2016-09-21

The search for colossal permittivity (CP) materials is imperative because of their potential for promising applications in the areas of device miniaturization and energy storage. High-performance CP materials require high dielectric permittivity, low dielectric loss and relatively weak dependence of frequency- and temperature. In this work, we first investigate the CP behavior of rutile TiO2 ceramics co-doped with niobium and erbium, i.e., (Er0.5Nb0.5)xTi1-xO2. Excellent dielectric properties were observed in the materials, including a CP of up to 10(4)-10(5) and a low dielectric loss (tan δ) down to 0.03, which are lower than that of the previously reported co-doped TiO2 CP materials when measured at 1 kHz. Stabilities of frequency and temperature were also accomplished via doping Er and Nb. Valence states of the elements in the material were analyzed using X-ray photoelectron spectroscopy. The Er induced secondary phases were observed using elemental mapping and energy-dispersive spectrometry. Consequently, this work may provide comprehensive guidance to develop high-performance CP materials for fully solid-state capacitor and energy storage applications.

High-Level Heteroatom Doped Two-Dimensional Carbon Architectures for Highly Efficient Lithium-Ion Storage

PubMed Central

Wang, Zhijie; Wang, Yanyan; Wang, Wenhui; Yu, Xiaoliang; Lv, Wei; Xiang, Bin; He, Yan-Bing

2018-01-01

In this work, high-level heteroatom doped two-dimensional hierarchical carbon architectures (H-2D-HCA) are developed for highly efficient Li-ion storage applications. The achieved H-2D-HCA possesses a hierarchical 2D morphology consisting of tiny carbon nanosheets vertically grown on carbon nanoplates and containing a hierarchical porosity with multiscale pore size. More importantly, the H-2D-HCA shows abundant heteroatom functionality, with sulfur (S) doping of 0.9% and nitrogen (N) doping of as high as 15.5%, in which the electrochemically active N accounts for 84% of total N heteroatoms. In addition, the H-2D-HCA also has an expanded interlayer distance of 0.368 nm. When used as lithium-ion battery anodes, it shows excellent Li-ion storage performance. Even at a high current density of 5 A g−1, it still delivers a high discharge capacity of 329 mA h g−1 after 1,000 cycles. First principle calculations verifies that such unique microstructure characteristics and high-level heteroatom doping nature can enhance Li adsorption stability, electronic conductivity and Li diffusion mobility of carbon nanomaterials. Therefore, the H-2D-HCA could be promising candidates for next-generation LIB anodes. PMID:29686985

Metal Phosphides and Phosphates-based Electrodes for Electrochemical Supercapacitors.

PubMed

Li, Xin; Elshahawy, Abdelnaby M; Guan, Cao; Wang, John

2017-10-01

Phosphorus compounds, such as metal phosphides and phosphates have shown excellent performances and great potential in electrochemical energy storage, which are demonstrated by research works published in recent years. Some of these metal phosphides and phosphates and their hybrids compare favorably with transition metal oxides/hydroxides, which have been studied extensively as a class of electrode materials for supercapacitor applications, where they have limitations in terms of electrical and ion conductivity and device stability. To be specific, metal phosphides have both metalloid characteristics and good electric conductivity. For metal phosphates, the open-framework structures with large channels and cavities endow them with good ion conductivity and charge storage capacity. In this review, we present the recent progress on metal phosphides and phosphates, by focusing on their advantages/disadvantages and potential applications as a new class of electrode materials in supercapacitors. The synthesis methods to prepare these metal phosphides/phosphates are looked into, together with the scientific insights involved, as they strongly affect the electrochemical energy storage performance. Particular attentions are paid to those hybrid-type materials, where strong synergistic effects exist. In the summary, the future perspectives and challenges for the metal phosphides, phosphates and hybrid-types are proposed and discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tuning the Shell Number of Multishelled Metal Oxide Hollow Fibers for Optimized Lithium-Ion Storage.

PubMed

Sun, Jin; Lv, Chunxiao; Lv, Fan; Chen, Shuai; Li, Daohao; Guo, Ziqi; Han, Wei; Yang, Dongjiang; Guo, Shaojun

2017-06-27

Searching the long-life transition-metal oxide (TMO)-based materials for future lithium-ion batteries (LIBs) is still a great challenge because of the mechanical strain resulting from volume change of TMO anodes during the lithiation/delithiation process. To well address this challenging issue, we demonstrate a controlled method for making the multishelled TMO hollow microfibers with tunable shell numbers to achieve the optimal void for efficient lithium-ion storage. Such a particularly designed void can lead to a short diffusion distance for fast diffusion of Li + ions and also withstand a large volume variation upon cycling, both of which are the key for high-performance LIBs. Triple-shelled TMO hollow microfibers are a quite stable anode material for LIBs with high reversible capacities (NiO: 698.1 mA h g -1 at 1 A g -1 ; Co 3 O 4 : 940.2 mA h g -1 at 1 A g -1 ; Fe 2 O 3 : 997.8 mA h g -1 at 1 A g -1 ), excellent rate capability, and stability. The present work opens a way for rational design of the void of multiple shells in achieving the stable lithium-ion storage through the biomass conversion strategy.

Stability of local anesthetics in the dental cartridge.

PubMed

Hondrum, S O; Seng, G F; Rebert, N W

1993-01-01

Recent manufacturer recalls of local anesthetics have emphasized the problems with storage stability. This article reviews the principles of drug stability, mechanisms of degradation of commonly used vasoconstrictors, research on the stability of commercially produced local anesthetic preparations, and possible effects of the container-closure system. The review concludes with a list of practical and clinical suggestions on how to minimize storage stability problems with dental local anesthetics.

Ultrasound-Mediated Tumor Imaging and Nanotherapy using Drug Loaded, Block Copolymer Stabilized Perfluorocarbon Nanoemulsions

PubMed Central

Rapoport, Natalya; Nam, Kweon-Ho; Gupta, Roohi; Gao, Zhongao; Mohan, Praveena; Payne, Allison; Todd, Nick; Liu, Xin; Kim, Taeho; Shea, Jill; Scaife, Courtney; Parker, Dennis L.; Jeong, Eun-Kee; Kennedy, Anne M.

2011-01-01

Perfluorocarbon nanoemulsions can deliver lipophilic therapeutic agents to solid tumors and simultaneously provide for monitoring nanocarrier biodistribution via ultrasonography and/or 19F MRI. In the first generation of block copolymer stabilized perfluorocarbon nanoemulsions, perfluoropentane (PFP) was used as the droplet forming compound. Although manifesting excellent therapeutic and ultrasound imaging properties, PFP nanoemulsions were unstable at storage, difficult to handle, and underwent hard to control phenomenon of irreversible droplet-to-bubble transition upon injection. To solve the above problems, perfluoro-15-crown-5-ether (PFCE) was used as a core forming compound in the second generation of block copolymer stabilized perfluorocarbon nanoemulsions. PFCE nanodroplets manifest both ultrasound and fluorine (19F) MR contrast properties, which allows using multimodal imaging and 19F MR spectroscopy for monitoring nanodroplet pharmacokinetics and biodistribution. In the present paper, acoustic, imaging, and therapeutic properties of unloaded and paclitaxel (PTX) loaded PFCE nanoemulsions are reported. As manifested by the 19F MR spectroscopy, PFCE nanodroplets are long circulating, with about 50% of the injected dose remaining in circulation two hours after the systemic injection. Sonication with 1-MHz therapeutic ultrasound triggered reversible droplet-to-bubble transition in PFCE nanoemulsions. Microbubbles formed by acoustic vaporization of nanodroplets underwent stable cavitation. The nanodroplet size (200 nm to 350 nm depending on a type of the shell and conditions of emulsification) as well as long residence in circulation favored their passive accumulation in tumor tissue that was confirmed by ultrasonography. In the breast and pancreatic cancer animal models, ultrasound-mediated therapy with paclitaxel-loaded PFCE nanoemulsions showed excellent therapeutic properties characterized by tumor regression and suppression of metastasis. Anticipated mechanisms of the observed effects are discussed. PMID:21277919

Expedited Development of Diphenhydramine Orally Disintegrating Tablet through Integrated Crystal and Particle Engineering.

PubMed

Wang, Chenguang; Hu, Shenye; Sun, Changquan Calvin

2017-10-02

A palatable direct compression (DC) orally disintegrating tablet (ODT) product of a bitter drug, diphenhydramine (DPH), was developed using an integrated crystal and particle engineering approach. A DPH salt with a sweetener, acesulfame (Acs), DPH-Acs, was synthesized and its solid state properties were comprehensively characterized. Tablet formulation composition and compaction parameters were optimized by employing material sparing techniques. In vivo disintegration time, bitterness, and grittiness of the final ODT product, were evaluated by a taste panel. Physical stability of the ODT tablets was assessed to identify appropriate storage conditions. Phase-pure DPH-Acs exhibited significantly better tabletability and palatability than DPH-HCl. A DC formulation was designed and optimized to obtain a new ODT product with good manufacturability and excellent product characteristics, including fast in vivo disintegration, and acceptable bitterness and grittiness. A new ODT product of DPH with excellent pharmaceutical properties was successfully developed using 15 g of DPH and in two months. This example shows that integrated crystal and particle engineering is an effective approach for developing high quality ODT products using the DC process.

Preparation of β-cyclodextrin entrapped graphite composite for sensitive detection of dopamine.

PubMed

Palanisamy, Selvakumar; Sakthinathan, S; Chen, Shen-Ming; Thirumalraj, Balamurugan; Wu, Tsung-Han; Lou, Bih-Show; Liu, Xiaoheng

2016-01-01

A simple dopamine (DA) electrochemical sensor was developed based on a screen-printed carbon electrode (SPCE) modified with β-cyclodextrin entrapped graphite (GR/β-CD) composite for the first time. The polar hydroxyl groups on the β-CD rims interact with polar groups of edges of GR sheets resulting into the high dispersion ability of GR in β-CD solution. The GR/β-CD modified electrode exhibited a higher electrochemical response to DA with a lower oxidation potential (0.224V) than that of bare/β-CD (0.38V) and GR (0.525V) modified SPCEs, revealing an excellent electro-oxidation behavior of GR/β-CD composite toward DA. Under optimum conditions, the fabricated sensor detects the DA in the linear concentration range from 0.1 to 58.5μM with a limit of detection of 0.011μM and the sensitivity of 1.27±0.02μAμM(-1)cm(-2). The fabricated sensor also exhibits the excellent repeatability, practicality, reproducibility, storage stability along with acceptable selectivity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Facilitated charge transport in ternary interconnected electrodes for flexible supercapacitors with excellent power characteristics.

PubMed

Chen, Wanjun; He, Yongmin; Li, Xiaodong; Zhou, Jinyuan; Zhang, Zhenxing; Zhao, Changhui; Gong, Chengshi; Li, Shuankui; Pan, Xiaojun; Xie, Erqing

2013-12-07

Flexible and high performance supercapacitors are very critical in modern society. In order to develop the flexible supercapacitors with high power density, free-standing and flexible three-dimensional graphene/carbon nanotubes/MnO2 (3DG/CNTs/MnO2) composite electrodes with interconnected ternary 3D structures were fabricated, and the fast electron and ion transport channels were effectively constructed in the rationally designed electrodes. Consequently, the obtained 3DG/CNTs/MnO2 composite electrodes exhibit superior specific capacitance and rate capability compared to 3DG/MnO2 electrodes. Furthermore, the 3DG/CNTs/MnO2 based asymmetric supercapacitor demonstrates the maximum energy and power densities of 33.71 W h kg(-1) and up to 22,727.3 W kg(-1), respectively. Moreover, the asymmetric supercapacitor exhibits excellent cycling stability with 95.3% of the specific capacitance maintained after 1000 cycle tests. Our proposed synthesis strategy to construct the novel ternary 3D structured electrodes can be efficiently applied to other high performance energy storage/conversion systems.

Photopolymer Electrolytes for Sustainable, Upscalable, Safe, and Ambient-Temperature Sodium-Ion Secondary Batteries.

PubMed

Bella, Federico; Colò, Francesca; Nair, Jijeesh R; Gerbaldi, Claudio

2015-11-01

The first example of a photopolymerized electrolyte for a sodium-ion battery is proposed herein. By means of a preparation process free of solvents, catalysts, purification steps, and separation steps, it is possible to obtain a three-dimensional polymeric network capable of efficient sodium-ion transport. The thermal properties of the resulting solid electrolyte separator, characterized by means of thermogravimetric and calorimetric techniques, are excellent for use in sustainable energy systems conceived for safe large-scale grid storage. The photopolymerized electrolyte shows a wide electrochemical stability window up to 4.8 V versus Na/Na(+) along with the highest ionic conductivity (5.1 mS cm(-1) at 20 °C) obtained in the field of Na-ion polymer batteries so far and stable long-term constant-current charge/discharge cycling. Moreover, the polymeric networks are also demonstrated for the in situ fabrication of electrode/electrolyte composites with excellent interfacial properties, which are ideal for all-solid-state, safe, and easily upscalable device assembly. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Facile Synthesis of Coaxial CNTs/MnOx-Carbon Hybrid Nanofibers and Their Greatly Enhanced Lithium Storage Performance.

PubMed

Yang, Zunxian; Lv, Jun; Pang, Haidong; Yan, Wenhuan; Qian, Kun; Guo, Tailiang; Guo, Zaiping

2015-12-01

Carbon nanotubes (CNTs)/MnOx-Carbon hybrid nanofibers have been successfully synthesized by the combination of a liquid chemical redox reaction (LCRR) and a subsequent carbonization heat treatment. The nanostructures exhibit a unique one-dimensional core/shell architecture, with one-dimensional CNTs encapsulated inside and a MnOx-carbon composite nanoparticle layer on the outside. The particular porous characteristics with many meso/micro holes/pores, the highly conductive one-dimensional CNT core, as well as the encapsulating carbon matrix on the outside of the MnOx nanoparticles, lead to excellent electrochemical performance of the electrode. The CNTs/MnOx-Carbon hybrid nanofibers exhibit a high initial reversible capacity of 762.9 mAhg(-1), a high reversible specific capacity of 560.5 mAhg(-1) after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 396.2 mAhg(-1) when cycled at the current density of 1000 mAg(-1), indicating that the CNTs/MnOx-Carbon hybrid nanofibers are a promising anode candidate for Li-ion batteries.

Facile Synthesis of Coaxial CNTs/MnOx-Carbon Hybrid Nanofibers and Their Greatly Enhanced Lithium Storage Performance

PubMed Central

Yang, Zunxian; Lv, Jun; Pang, Haidong; Yan, Wenhuan; Qian, Kun; Guo, Tailiang; Guo, Zaiping

2015-01-01

Carbon nanotubes (CNTs)/MnOx-Carbon hybrid nanofibers have been successfully synthesized by the combination of a liquid chemical redox reaction (LCRR) and a subsequent carbonization heat treatment. The nanostructures exhibit a unique one-dimensional core/shell architecture, with one-dimensional CNTs encapsulated inside and a MnOx-carbon composite nanoparticle layer on the outside. The particular porous characteristics with many meso/micro holes/pores, the highly conductive one-dimensional CNT core, as well as the encapsulating carbon matrix on the outside of the MnOx nanoparticles, lead to excellent electrochemical performance of the electrode. The CNTs/MnOx-Carbon hybrid nanofibers exhibit a high initial reversible capacity of 762.9 mAhg−1, a high reversible specific capacity of 560.5 mAhg−1 after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 396.2 mAhg−1 when cycled at the current density of 1000 mAg−1, indicating that the CNTs/MnOx-Carbon hybrid nanofibers are a promising anode candidate for Li-ion batteries. PMID:26621615

Electrochemical investigation of MoTe2/rGO composite materials for sodium-ion battery application

NASA Astrophysics Data System (ADS)

Panda, Manas Ranjan; Anish Raj, K.; Sarkar, Ananta; Bao, Qiaoliang; Mitra, Sagar

2018-05-01

2D layered materials are found to be promising anode materials for renewable energy storage devices like sodium and Li-ion batteries and have become attractive options due to their high specific capacity, abundance and low cost. In this work, we synthesized 2D MoTe2 layers embedded in reduced graphene oxide (rGO) anode material for sodium-ion battery applications. 2D MoTe2 was prepared by a solid-state reaction in vacuum at a temperature of 800 °C. The prepared composite material MoTe2/rGO showed excellent electrochemical performance against the sodium metal. The discharge capacity of MoTe2/rGO was observed to be 280 mAh g-1 at a current rate of 1.0 A g-1 for 100 cycles. rGO plays an important role in embedding the MoTe2 structure, thus improving the electrical and mechanical properties, leading to a superior cycling stability and excellent electrochemical performances of MoTe2 for sodium-ion battery applications.

Towards muscle-specific meat color stability of Chinese Luxi yellow cattle: A proteomic insight into post-mortem storage.

PubMed

Wu, Wei; Yu, Qian-Qian; Fu, Yu; Tian, Xiao-Jing; Jia, Fei; Li, Xing-Min; Dai, Rui-Tong

2016-09-16

Searching for potential predictors of meat color is a challenging task for the meat industry. In this study, the relationship between meat color parameters and the sarcoplasmic proteome of M. longissimuss lumborum (LL) and M. psoas major (PM) from Chinese Luxi yellow cattle during post-mortem storage (0, 5, 10 and 15days) were explored with the aid of the integrated proteomics and bioinformatics approaches. Meat color attributes revealed that LL displayed better color stability than PM during storage. Furthermore, sarcoplasmic proteins of these two muscles were compared between days 5, 10, 15 and day 0. Several proteins were closely correlated with meat color attributes and they were muscle-specific and responsible for the meat color stability at different storage periods. Glycerol-3-phosphate dehydrogenase, fructose-bisphosphate aldolase A isoform, glycogen phosphorylase, peroxiredoxin-2, phosphoglucomutase-1, superoxide dismutase [Cu-Zn], heat shock cognate protein (71kDa) might serve as the candidate predictors of meat color stability during post-mortem storage. In addition, bioinformatics analyses indicated that more proteins were involved in glycolytic metabolism of LL, which contributed to better meat color stability of LL than PM. The present results could provide a proteomic insight into muscle-specific meat color stability of Chinese Luxi yellow cattle during post-mortem storage. Copyright © 2015 Elsevier B.V. All rights reserved.

Large-Area Carbon Nanosheets Doped with Phosphorus: A High-Performance Anode Material for Sodium-Ion Batteries.

PubMed

Hou, Hongshuai; Shao, Lidong; Zhang, Yan; Zou, Guoqiang; Chen, Jun; Ji, Xiaobo

2017-01-01

Large-area phosphorus-doped carbon nanosheets (P-CNSs) are first obtained from carbon dots (CDs) through self-assembly driving from thermal treatment with Na catalysis. This is the first time to realize the conversion from 0D CDs to 2D nanosheets doped with phosphorus. The sodium storage behavior of phosphorus-doped carbon material is also investigated for the first time. As anode material for sodium-ion batteries (SIBs), P-CNSs exhibit superb performances for electrochemical storage of sodium. When cycled at 0.1 A g -1 , the P-CNSs electrode delivers a high reversible capacity of 328 mAh g -1 , even at a high current density of 20 A g -1 , a considerable capacity of 108 mAh g -1 can still be maintained. Besides, this material also shows excellent cycling stability, at a current density of 5 A g -1 , the reversible capacity can still reach 149 mAh g -1 after 5000 cycles. This work will provide significant value for the development of both carbon materials and SIBs anode materials.

One-step electrodeposited nickel cobalt sulfide nanosheet arrays for high-performance asymmetric supercapacitors.

PubMed

Chen, Wei; Xia, Chuan; Alshareef, Husam N

2014-09-23

A facile one-step electrodeposition method is developed to prepare ternary nickel cobalt sulfide interconnected nanosheet arrays on conductive carbon substrates as electrodes for supercapacitors, resulting in exceptional energy storage performance. Taking advantages of the highly conductive, mesoporous nature of the nanosheets and open framework of the three-dimensional nanoarchitectures, the ternary sulfide electrodes exhibit high specific capacitance (1418 F g(-1) at 5 A g(-1) and 1285 F g(-1) at 100 A g(-1)) with excellent rate capability. An asymmetric supercapacitor fabricated by the ternary sulfide nanosheet arrays as positive electrode and porous graphene film as negative electrode demonstrates outstanding electrochemical performance for practical energy storage applications. Our asymmetric supercapacitors show a high energy density of 60 Wh kg(-1) at a power density of 1.8 kW kg(-1). Even when charging the cell within 4.5 s, the energy density is still as high as 33 Wh kg(-1) at an outstanding power density of 28.8 kW kg(-1) with robust long-term cycling stability up to 50,000 cycles.

Three-Dimensional Bi-Continuous Nanoporous Gold/Nickel Foam Supported MnO2 for High Performance Supercapacitors.

PubMed

Zhao, Jie; Zou, Xilai; Sun, Peng; Cui, Guofeng

2017-12-19

A three-dimensional bi-continuous nanoporous gold (NPG)/nickel foam is developed though the electrodeposition of a gold-tin alloy on Ni foam and subsequent chemical dealloying of tin. The newly-designed 3D metal structure is used to anchor MnO 2 nanosheets for high-performance supercapacitors. The formed ternary composite electrodes exhibit significantly-enhanced capacitance performance, rate capability, and excellent cycling stability. A specific capacitance of 442 Fg -1 is achieved at a scan rate of 5 mV s -1 and a relatively high mass loading of 865 μg cm -2 . After 2500 cycles, only a 1% decay is found at a scan rate of 50 mV s -1 . A high power density of 3513 W kg -1 and an energy density of 25.73 Wh kg -1 are realized for potential energy storage devices. The results demonstrate that the NPG/nickel foam hybrid structure significantly improves the dispersibility of MnO 2 and makes it promising for practical energy storage applications.

Whey powders are a rich source and excellent storage matrix for dairy bacteriophages.

PubMed

Wagner, Natalia; Brinks, Erik; Samtlebe, Meike; Hinrichs, Jörg; Atamer, Zeynep; Kot, Witold; Franz, Charles M A P; Neve, Horst; Heller, Knut J

2017-01-16

Thirteen whey powders and 5 whey powder formulations were screened for the presence of dairy bacteriophages using a representative set of 8 acid-producing Lactococcus lactis and 5 Streptococcus thermophilus, and 8 flavour-producing Leuconostoc pseudomesenteroides and Leuconostoc mesenteroides strains. Lytic L. lactis phages were detected in all samples, while S. thermophilus and Leuconostoc phages were present in 50% or 40% of the samples, respectively. Maximal phage titers were 6×10 7 plaque-forming units (pfu)/g of whey powder for L. lactis phages, 1×10 7 pfu/g for Leuconostoc phages and 1×10 5 pfu/g for S. thermophilus phages. In total, 55 phages were isolated and characterized. Thirty one of the 33 lactococcal phages tested belonged to the wide-spread 936 phage group. In the course of this study, a PCR detection method for Leuconostoc phages (Ali et al., 2013) was adapted to new phage isolates. Furthermore, a remarkably high stability of phages in whey powder samples was documented during a long-term storage period of 4 years. Copyright © 2016 Elsevier B.V. All rights reserved.

Supramolecular assembled three-dimensional graphene hybrids: Synthesis and applications in supercapacitors

NASA Astrophysics Data System (ADS)

Ni, Lubin; Zhang, Wang; Wu, Zhen; Sun, Chunyu; Cai, Yin; Yang, Guang; Chen, Ming; Piao, Yuanzhe; Diao, Guowang

2017-02-01

Graphene-based materials have received worldwide attention in the focus of forefront energy storage investigations. Currently, the design of novel three-dimensional (3D) graphene structures with high energy capability, superior electron and ion conductivity, and robust mechanical flexibility is still a great challenge. Herein, we have successfully demonstrated a novel approach to fabricate 3D assembled graphene through the supramolecular interactions of β-cyclodextrin polymers (β-CDP) with an adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD). The incorporation of PEG-AD linker into rGO sheets increased the interlayer spacing of rGO sheets to form 3D graphene materials, which can provide efficient 3D electron transfer pathways and ion diffusion channels, and facilitate the infiltration of gel electrolyte. The as-prepared 3D self-assembled graphene materials exhibit significantly improved electrochemical performances of supercapacitor in terms of high specific capacitance, remarkable rate capability, and excellent cycling stability compared to pristine reduced graphene oxide. This study shed new lights to the construction of three dimensional self-assembled graphene materials and their urgent applications in energy storage.

LiCl-LiI molten salt electrolyte with bismuth-lead positive electrode for liquid metal battery

NASA Astrophysics Data System (ADS)

Kim, Junsoo; Shin, Donghyeok; Jung, Youngjae; Hwang, Soo Min; Song, Taeseup; Kim, Youngsik; Paik, Ungyu

2018-02-01

Liquid metal batteries (LMBs) are attractive energy storage device for large-scale energy storage system (ESS) due to the simple cell configuration and their high rate capability. The high operation temperature caused by high melting temperature of both the molten salt electrolyte and metal electrodes can induce the critical issues related to the maintenance cost and degradation of electrochemical properties resulting from the thermal corrosion of materials. Here, we report a new chemistry of LiCl-LiI electrolyte and Bi-Pb positive electrode to lower the operation temperature of Li-based LMBs and achieve the long-term stability. The cell (Li|LiCl-LiI|Bi-Pb) is operated at 410 °C by employing the LiCl-LiI (LiCl:LiI = 36:64 mol %) electrolyte and Bi-Pb alloy (Bi:Pb = 55.5:44.5 mol %) positive electrode. The cell shows excellent capacity retention (86.5%) and high Coulombic efficiencies over 99.3% at a high current density of 52 mA cm-2 during 1000th cycles.

Hydroxylamine hydrochloride: A novel anode material for high capacity lithium-ion batteries

NASA Astrophysics Data System (ADS)

Shao, Lianyi; Shu, Jie; Lao, Mengmeng; Lin, Xiaoting; Wu, Kaiqiang; Shui, Miao; Li, Peng; Long, Nengbing; Ren, Yuanlong

2014-12-01

H3NOHCl is used for the first time as anode material for lithium-ion batteries. Electrochemical results show that H3NOHCl with particle size of 4-12 μm can deliver an initial charge capacity of 1018.6 mAh g-1, which is much higher than commercial graphite. After 30 cycles, the reversible capacity can be kept at 676.1 mAh g-1 at 50 mA g-1. Up to 50 cycles, H3NOHCl still maintains a lithium storage capacity of 368.9 mAh g-1. Even cycled at 200 mA g-1, H3NOHCl can deliver a charge capacity of 715.7 mAh g-1. It suggests that H3NOHCl has high lithium storage capacity, excellent cycling stability and outstanding rate performance. Besides, the electrochemical reaction between H3NOHCl and Li is also investigated by various ex-situ techniques. It can be found that H3NOHCl irreversibly decomposes into Li3N and LiCl during the initial discharge process and LiNO2 can be formed after a reverse charge process.

A Safe High-Performance All-Solid-State Lithium-Vanadium Battery with a Freestanding V2O5 Nanowire Composite Paper Cathode.

PubMed

Zhang, Yue; Lai, Jingyuan; Gong, Yudong; Hu, Yongming; Liu, Jin; Sun, Chunwen; Wang, Zhong Lin

2016-12-21

The electronic conductivity and structural stability are still challenges for vanadium pentoxide (V 2 O 5 ) as cathode materials in batteries. Here, we report a V 2 O 5 nanowire-reduced graphene oxide (rGO) composite paper for direct use as a cathode without any additives for high-temperature and high-safety solid polymer electrolyte [PEO-MIL-53(Al)-LiTFSI] lithium-vanadium batteries. The batteries can show a fast and stable lithium-ion-storage performance in a wide voltage window of 1.0-4.0 V versus Li + /Li at 80 °C, in which with an average capacity of 329.2 mAh g -1 at 17 mA g -1 and a stable cycling performance over 40 cycles are achieved. The excellent electrochemical performance is mainly ascribed to integration of the electronic conductivity of rGO and interconnected networks of the V 2 O 5 nanowires and solid electrolyte. This is a promising lithium battery for flexible and highly safe energy-storage devices.

Ant-cave structured MnCO3/Mn3O4 microcubes by biopolymer-assisted facile synthesis for high-performance pseudocapacitors

NASA Astrophysics Data System (ADS)

Chandra Sekhar, S.; Nagaraju, Goli; Yu, Jae Su

2018-03-01

Porous and ant-cave structured MnCO3/Mn3O4 microcubes (MCs) were facilely synthesized via a biopolymer-assisted hydrothermal approach. Herein, chitosan was used as a natural biopolymer, which greatly controls the surface morphology and size of the prepared composite. The amino and hydroxyl group-functionalized chitosan engraves the outer surface of MCs during the hydrothermal process, which designs the interesting morphology of nanopath ways on the surface of MCs. When used as an electrode material for pseudocapacitors, the ant-cave structured MnCO3/Mn3O4 MCs showed superior energy storage values compared to the material prepared without chitosan in aqueous electrolyte solution. Precisely, the prepared ant-cave structured MnCO3/Mn3O4 MCs exhibited a maximum specific capacitance of 116.2 F/g at a current density of 0.7 A/g with an excellent cycling stability of 73.86% after 2000 cycles. Such facile and low-cost synthesis of pseudocapacitive materials with porous nanopaths is favorable for the fabrication of high-performance energy storage devices.

Stability of selected volatile contact allergens in different patch test chambers under different storage conditions.

PubMed

Mose, Kristian F; Andersen, Klaus E; Christensen, Lars Porskjaer

2012-04-01

Patch test preparations of volatile substances may evaporate during storage, thereby giving rise to reduced patch test concentrations. To investigate the stability of selected acrylates/methacrylates and fragrance allergens in three different test chambers under different storage conditions. Petrolatum samples of methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (2-HEMA), 2-hydroxypropyl acrylate (2-HPA), cinnamal and eugenol in patch test concentrations were stored in three different test chambers (IQ chamber™, IQ Ultimate™, and Van der Bend® transport container) at room temperature and in a refrigerator. The samples were analysed in triplicate with high-performance liquid chromatography. The decrease in concentration was substantial for all five allergens under both storage conditions in IQ chamber™ and IQ Ultimate™, with the exception of 2-HEMA during storage in the refrigerator. For these two chamber systems, the contact allergen concentration dropped below the stability limit in the following order: MMA, cinnamal, 2-HPA, eugenol, and 2-HEMA. In the Van der Bend® transport container, the contact allergens exhibited acceptable stability under both storage conditions, whereas MMA and 2-HPA required cool storage for maintenance of the limit. The Van der Bend® transport container was the best device for storage of samples of volatile contact allergens. © 2012 John Wiley & Sons A/S.

Hollow/porous nanostructures derived from nanoscale metal-organic frameworks towards high performance anodes for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Hu, Lin; Chen, Qianwang

2014-01-01

Lithium-ion batteries (LIBs), owing to their high energy density, light weight, and long cycle life, have shown considerable promise for storage devices. The successful utilization of LIBs depends strongly on the preparation of nanomaterials with outstanding lithium storage properties. Recent progress has demonstrated that hollow/porous nanostructured oxides are very attractive candidates for LIBs anodes due to their high storage capacities. Here, we aim to provide an overview of nanoscale metal-organic frameworks (NMOFs)-templated synthesis of hollow/porous nanostructured oxides and their LIBs applications. By choosing some typical NMOFs as examples, we present a comprehensive summary of synthetic procedures for nanostructured oxides, such as binary, ternary and composite oxides. Hollow/porous structures are readily obtained due to volume loss and release of internally generated gas molecules during the calcination of NMOFs in air. Interestingly, the NMOFs-derived hollow/porous structures possess several special features: pores generated from gas molecules release will connect to each other, which are distinct from ``dead pores'' pore size often appears to be <10 nm; in terms of surface chemistry, the pore surface is hydrophobic. These structural features are believed to be the most critical factors that determine LIBs' performance. Indeed, it has been shown that these NMOFs-derived hollow/porous oxides exhibit excellent electrochemical performance as anode materials for LIBs, including high storage capacity, good cycle stability, and so on. For example, a high charge capacity of 1465 mA h g-1 at a rate of 300 mA g-1 was observed after 50 cycles for NMOFs-derived Co3O4 porous nanocages, which corresponds to 94.09% of the initial capacity (1557 mA h g-1), indicating excellent stability. The capacity of NMOFs-derived Co3O4 is higher than that of other Co3O4 nanostructures obtained by a conventional two-step route, including nanosheets (1450 mA h g-1 at 50 mA g-1), nanobelts (1400 mA h g-1 at 40 mA g-1) and nanoflowers (694 mA h g-1 at 100 mA g-1). The capacity is also better than Co3O4 octahedra obtained by a one-step hydrothermal method (946 mA h g-1 at 100 mA g-1). In this review, we will summarize the recent research advances on NMOFs-derived hollow/porous oxides as LIBs anodes. The enhanced lithium storage properties have been discussed in relation to their special structural parameters. Moreover, remarks on the current challenges and perspectives for future NMOFs applications are proposed. Through this systematic review, we aim to stress the importance of NMOFs templates for the fabrication of hollow/porous functional materials that would result in improved physicochemical properties and provide insights to guide future research for LIBs applications.

A one-step in-situ assembly strategy to construct PEG@MOG-100-Fe shape-stabilized composite phase change material with enhanced storage capacity for thermal energy storage

NASA Astrophysics Data System (ADS)

Wang, Junyong; Andriamitantsoa, Radoelizo S.; Atinafu, Dimberu G.; Gao, Hongyi; Dong, Wenjun; Wang, Ge

2018-03-01

A novel in-situ assembly strategy has been developed to synthesis polyethylene glycol (PEG)@iron-benzenetricarboxylate metal-organic gel (MOG-100-Fe) shape-stabilized composite phase change materials by regulating metal-to-ligand ratio. The PEG@MOG-100-Fe was prepared by an ingenious introduction of PEG into the traditional sol-gel prepared MOG-100-Fe. The composite exhibited high heat storage density and thermal stability. The PEG loading content reached up to 92% without any leakage above its melting point. The heat storage density reaches to 152.88

Stability of Tranexamic Acid after 12-Week Storage at Temperatures from -20 deg C to 50 deg C

DTIC Science & Technology

2013-07-01

PRELIMINARY REPORTS STABILITY OF TRANEXAMIC ACID AFTER 12-WEEK STORAGE AT TEMPERATURES FROM –20◦C TO 50◦C Rodolfo de Guzman, Jr., MT, I. Amy...Polykratis, BS, Jill L. Sondeen, PhD, Daniel N. Darlington, PhD, Andrew P. Cap, MD, PhD, Michael A. Dubick, PhD ABSTRACT Background. Tranexamic acid (TXA) is... tranexamic acid ; temperature stability; HPLC; thromboelastography; storage PREHOSPITAL EMERGENCY CARE 2013;17:394–400 BACKGROUND Hemorrhage is the leading

High-yield harvest of nanofibers/mesoporous carbon composite by pyrolysis of waste biomass and its application for high durability electrochemical energy storage.

PubMed

Liu, Wu-Jun; Tian, Ke; He, Yan-Rong; Jiang, Hong; Yu, Han-Qing

2014-12-02

Disposal and recycling of the large scale biomass waste is of great concern. Themochemically converting the waste biomass to functional carbon nanomaterials and bio-oil is an environmentally friendly apporach by reducing greenhouse gas emissions and air pollution caused by open burning. In this work, we reported a scalable, "green" method for the synthesis of the nanofibers/mesoporous carbon composites through pyrolysis of the Fe(III)-preloaded biomass, which is controllable by adjustment of temperature and additive of catalyst. It is found that the coupled catalytic action of both Fe and Cl species is able to effectively catalyze the growth of the carbon nanofibers on the mesoporous carbon and form magnetic nanofibers/mesoporous carbon composites (M-NMCCs). The mechanism for the growth of the nanofibers is proposed as an in situ vapor deposition process, and confirmed by the XRD and SEM results. M-NMCCs can be directly used as electrode materials for electrochemical energy storage without further separation, and exhibit favorable energy storage performance with high EDLC capacitance, good retention capability, and excellent stability and durability (more than 98% capacitance retention after 10,000 cycles). Considering that biomass is a naturally abundant and renewable resource (over billions tons biomass produced every year globally) and pyrolysis is a proven technique, M-NMCCs can be easily produced at large scale and become a sustainable and reliable resource for clean energy storage.

ICI optical data storage tape: An archival mass storage media

NASA Technical Reports Server (NTRS)

Ruddick, Andrew J.

1993-01-01

At the 1991 Conference on Mass Storage Systems and Technologies, ICI Imagedata presented a paper which introduced ICI Optical Data Storage Tape. This paper placed specific emphasis on the media characteristics and initial data was presented which illustrated the archival stability of the media. More exhaustive analysis that was carried out on the chemical stability of the media is covered. Equally important, it also addresses archive management issues associated with, for example, the benefits of reduced rewind requirements to accommodate tape relaxation effects that result from careful tribology control in ICI Optical Tape media. ICI Optical Tape media was designed to meet the most demanding requirements of archival mass storage. It is envisaged that the volumetric data capacity, long term stability and low maintenance characteristics demonstrated will have major benefits in increasing reliability and reducing the costs associated with archival storage of large data volumes.

Accelerated Storage Stability and Corrosion Characteristics Study Protocol

EPA Pesticide Factsheets

EPA has determined that studies using this protocol will, in certain circumstances, provide the Agency with all the information it needs to make a determination on the storage stability of pesticides.

A flexible 3D nitrogen-doped carbon foam@CNTs hybrid hosting TiO2 nanoparticles as free-standing electrode for ultra-long cycling lithium-ion batteries

NASA Astrophysics Data System (ADS)

Yuan, Wei; Wang, Boya; Wu, Hao; Xiang, Mingwu; Wang, Qiong; Liu, Heng; Zhang, Yun; Liu, Huakun; Dou, Shixue

2018-03-01

Free-standing electrodes have stood out from the electrode pack, owing to their advantage of abandoning the conventional polymeric binder and conductive agent, thus increasing the specific capacity of lithium-ion batteries. Nevertheless, their practical application is hampered by inferior electrical conductivity and complex manufacturing process. To this end, we report here a facile approach to fabricate a flexible 3D N-doped carbon foam/carbon nanotubes (NCF@CNTs) hybrid to act as the current collector and host scaffold for TiO2 particles, which are integrated into a lightweight free-standing electrode (NCF@CNTs-TiO2). In the resulting architecture, ultra-fine TiO2 nanoparticles are homogeneously anchored in situ into the N-doped NCF@CNTs framework with macro- and meso-porous structure, wrapped by a dense CNT layer, cooperatively enhances the electrode flexibility and forms an interconnected conductive network for electron/ion transport. As a result, the as-prepared NCF@CNTs-TiO2 electrode exhibits excellent lithium storage performance with high specific capacity of 241 mAh g-1 at 1 C, superb rate capability of 145 mAh g-1 at 20 C, ultra-long cycling stability with an ultra-low capacity decay of 0.0037% per cycle over 2500 cycles, and excellent thermal stability with ∼94% capacity retention over 100 cycles at 55 °C.

Synthesis of hierarchical ZnV2O6 nanosheets with enhanced activity and stability for visible light driven CO2 reduction to solar fuels

NASA Astrophysics Data System (ADS)

Bafaqeer, Abdullah; Tahir, Muhammad; Amin, Nor Aishah Saidina

2018-03-01

Hierarchical nanostructures have lately garnered enormous attention because of their remarkable performances in energy storage and catalysis applications. In this study, novel hierarchical ZnV2O6 nanosheets, formulated by one-step solvothermal method, for enhanced photocatalytic CO2 reduction with H2O to solar fuels has been investigated. The structure and properties of the catalysts were characterized by XRD, FESEM, TEM, BET, UV-vis, Raman and PL spectroscopy. The hierarchical ZnV2O6 nanosheets show excellent performance towards photoreduction of CO2 with H2O to CH3OH, CH3COOH and HCOOH under visible light. The main product yield, CH3OH of 3253.84 μmol g-cat-1 was obtained over ZnV2O6, 3.4 times the amount of CH3OH produced over the ZnO/V2O5 composite (945.28 μmol g-cat-1). In addition, CH3OH selectivity of 39.96% achieved over ZnO/V2O5, increased to 48.78% in ZnV2O6 nanosheets. This significant improvement in photo-activity over ZnV2O6 structure was due to hierarchical structure with enhanced charge separation by V2O5. The obtained ZnV2O6 hierarchical nanosheets exhibited excellent photocatalytic stability for selective CH3OH production.

Controllable fabrication of urchin-like Co3O4 hollow spheres for high-performance supercapacitors and lithium-ion batteries.

PubMed

Chen, Fashen; Liu, Xiaohe; Zhang, Zhian; Zhang, Ning; Pan, Anqiang; Liang, Shuquan; Ma, Renzhi

2016-09-27

Urchin-like cobalt oxide (Co 3 O 4 ) hollow spheres can be successfully prepared by thermal decomposition of cobalt carbonate hydroxide hydrate (Co(CO 3 ) 0.5 (OH)·0.11H 2 O) obtained by template-assisted hydrothermal synthesis. The morphology, crystal structure evolution and thermal decomposition behaviors of the as-prepared products have been carefully investigated. A plausible formation mechanism of the urchin-like Co 3 O 4 hollow spheres in the presence of hexadecyl trimethyl ammonium bromide (CTAB) as the surfactant template is proposed. The urchin-like Co 3 O 4 hollow spheres are further constructed as electrode materials for high-performance supercapacitors with a high specific capacitance of 460 F g -1 at a current density of 4 A g -1 and excellent cycling stability. Furthermore, as anode materials for lithium-ion batteries (LIBs), superior lithium storage performance of 1342.2 mA h g -1 (0.1 C) and 1122.7 mA h g -1 (0.2 C) can also be achieved. The excellent performances can be ascribed to the unique hierarchical urchin-like hollow structure of the electrode materials, which offers a large specific surface area, short electron and ion diffusion paths and high permeability while being directly in contact with the electrolyte. Moreover, the hollow structure with sufficient internal void spaces can self-accommodate volume change during electrochemical reactions, which improves the structural stability and integrity.

Stability of lutein encapsulated whey protein nano-emulsion during storage

PubMed Central

Guo, Mingruo

2018-01-01

Lutein is a hydrophobic carotenoid that has multiple health functions. However, the application of lutein is limited due to its poor solubility in water and instability under certain conditions during storage. Hereby we generated lutein loaded nano-emulsions using whey protein isolate (WPI) or polymerized whey protein isolate (PWP) with assistance of high intensity ultrasound and evaluate their stability during storage at different conditions. We measured the particle size, zeta-potential, physical stability and lutein content change. Results showed that the PWP based nano-emulsion system was not stable in the tested Oil/Water/Ethanol system indicated by the appearance of stratification within only one week. The WPI based nano-emulsion system showed stable physiochemical stability during the storage at 4°C. The lutein content of the system was reduced by only 4% after four weeks storage at 4°C. In conclusion, our whey protein based nano-emulsion system provides a promising strategy for encapsulation of lutein or other hydrophobic bioactive molecules to expand their applications. PMID:29415071

Storage stability and composition changes of three cold-pressed nut oils under refrigeration and room temperature conditions.

PubMed

Rabadán, Adrián; Álvarez-Ortí, Manuel; Pardo, José Emilio; Alvarruiz, Andrés

2018-09-01

Chemical composition and stability parameters of three cold-pressed nut oils (almond, walnut and pistachio) were monitored for up to 16 months of storage at 5 °C, 10 °C, 20 °C and room temperature. Freshly pressed pistachio oil had lower peroxide value than almond oil and higher induction period than almond and walnut oils, indicating a higher stability. The peroxide values increased faster at room temperature than at lower temperatures during the storage time, and the highest increase was for pistachio oil stored at room temperature exposed to daylight. The induction period decreased for all three nut oils during the storage time, regardless of the storage conditions. Pistachio oil remained the most stable oil at the end of the storage time, followed by almond oil. The percentage of polyunsaturated fatty acids decreased slightly throughout the storage. Copyright © 2018 Elsevier Ltd. All rights reserved.

[THERMAL STABILITY AS A PROGNOSTIC INDICATOR OF CONSERVATION OF LIVE EMBRYONIC SMALLPOX VACCINE (TEOVAC) DURING STORAGE].

PubMed

Zhukov, V A; Kokorev, S V; Rogozhkina, S V; Melnikov, D G; Terentiev, A I; Kovalchuk, E A; Vakhnov, E Yu; Borisevich, S V

2016-01-01

Determination of values of coefficients of thermal stability of TEOVac for prognosis of conservation of the vaccine (specific biological activity) during the process of warranty period storage. TEOVac (masticatory tablets) in primary packaging was kept at increased temperature (accelerated and stress-tests) and at the conditions established by PAP for the preparation (long-term tests). Biological activity of the vaccine was determined by titration on 12-day chicken embryos. A correlation between the value of coefficients of thermal stability and conservation of the prepared series of the condition preparation at the final date of storage was experimentally established. Coefficients of thermal stability could be used as a prognostic indicator of quality of the produced pelleted formulation of the preparation for evaluation of conservation of the vaccine during warranty period storage.

Effect of light, packaging condition and dark storage durations on colour and lipid oxidative stability of cooked ham.

PubMed

Haile, Demewez Moges; De Smet, Stefaan; Claeys, Erik; Vossen, Els

2013-04-01

The colour and lipid oxidative stability of sliced cooked ham stored at 4 °C were studied in relation to dark storage duration, lighting and packaging conditions. Colour stability was monitored by instrumental colour measurement (CIE L*a*b* colour space) whereas lipid stability was measured by the determination of the 2-thiobarbituric acid reactive substances (TBARS). A significantly higher discoloration observed in products wrapped in foil and kept in light than products wrapped in foil and kept in dark. Colour loss was estimated by loss of redness (a*), a*/b*, nitrosomyoglobin, chroma (C); or increase of lightness (L*), MetMb, hue angle (H°). Colour loss was more dependent upon photochemical process than dark storage duration and packaging types. Lipid oxidation was not significantly affected by light exposure. However lipid oxidation was significantly affected by dark storage duration as noticed from better lipid stability of products stored for short duration in dark. Better colour stability was observed on products packed in MAP with less residual oxygen.

NaTi2(PO4)3 as an Aqueous Anode: Degradation Mechanisms and Mitigation Techniques

NASA Astrophysics Data System (ADS)

Mohamed, Alexander I.

With the proliferation of renewable energy sources, there has been a growing interest in battery chemistries for grid scale energy storage. Aqueous sodium ion batteries are particularly interesting for large scale energy storage because of their low cost and high safety, however, they tend to show poor long term stability. NaTi2(PO4)3 (NTP) shows promise as an anode for these systems with excellent long term stability when cycled quickly. When cycled slowly, NaTi2(PO4) 3 shows rapid capacity fade. The reasons for this rate depend capacity fade is poorly understood and is the topic of this document. It has been found that the products of the hydrogen evolution reaction, H2(g) and OH-, are the two largest contributors to capacity fade. High electrolyte pH caused by generation of OH- promotes dissolution of NTP during extend cycling, this is exacerbated when the pH increase above 11. The single greatest cause of apparent capacity fade for this material is loss of electrochemical surface area due to hydrogen gas entrapment within the porous structure of the electrode. Capacity lost in this manner can be recovered through reinfiltration of the electrode. The detrimental effects of gas entrapment within the electrode can be partially mitigated through compositing of the electrode with activated carbon and enhancing the wettability of the pores through addition of a surfactant to the electrolyte.

Tailoring the morphology followed by the electrochemical performance of NiMn-LDH nanosheet arrays through controlled Co-doping for high-energy and power asymmetric supercapacitors.

PubMed

Singh, Saurabh; Shinde, Nanasaheb M; Xia, Qi Xun; Gopi, Chandu V V M; Yun, Je Moon; Mane, Rajaram S; Kim, Kwang Ho

2017-10-14

Herein, we tailor the surface morphology of nickel-manganese-layered double hydroxide (NiMn-LDH) nanostructures on 3D nickel-foam via a step-wise cobalt (Co)-doping hydrothermal chemical process. At the 10% optimum level of Co-doping, we noticed a thriving tuned morphological pattern of NiMn-LDH nanostructures (NiCoMn-LDH (10%)) in terms of the porosity of the nanosheet (NS) arrays which not only improves the rate capability as well as cycling stability, but also demonstrates nearly two-fold specific capacitance enhancement compared to Co-free and other NiCoMn-LDH electrodes with a half-cell configuration in 3 M KOH, suggesting that Co-doping is indispensable for improving the electrochemical performance of NiMn-LDH electrodes. Moreover, when this high performing NiCoMn-LDH (10%) electrode is employed as a cathode material to fabricate an asymmetric supercapacitor (ASC) device with reduced graphene oxide (rGO) as an anode material, excellent energy storage performance (57.4 Wh kg -1 at 749.9 W kg -1 ) and cycling stability (89.4% capacitive retention even after 2500 cycles) are corroborated. Additionally, we present a demonstration of illuminating a light emitting diode for 600 s with the NiCoMn-LDH (10%)//rGO ASC device, evidencing the potential of the NiCoMn-LDH (10%) electrode in fabricating energy storage devices.

Investigation of the stability of Co-doped apatite ionic conductors in NH 3

NASA Astrophysics Data System (ADS)

Headspith, D. A.; Orera, A.; Slater, P. R.; Young, N. A.; Francesconi, M. G.

2010-12-01

Hydrogen powered solid oxide fuel cells (SOFCs) are of enormous interest as devices for the efficient and clean production of electrical energy. However, a number of problems linked to hydrogen production, storage and transportation are slowing down the larger scale use of SOFCs. Identifying alternative fuel sources to act as intermediate during the transition to the full use of hydrogen is, therefore, of importance. One excellent alternative is ammonia, which is produced on a large scale, is relatively cheap and has the infrastructure for storage and transportation already in place. However, considering that SOFCs operate at temperatures higher than 500 °C, a potential problem is the interaction of gaseous ammonia with the materials in the cathode, anode and solid electrolyte. In this paper, we extend earlier work on high temperature reactions of apatite electrolytes with NH 3 to the transition metal (Co) doped systems, La 9.67Si 5CoO 26 and La 10(Si/Ge) 5CoO 26.5. A combination of PXRD, TGA and XAFS spectroscopy data showed a better structural stability for the silicate systems. Apatite silicates and germanates not containing transition metals tend to substitute nitride anions for their interstitial oxide anions, when reacted with NH 3 at high temperature and, consequentially, lower the interstitial oxide content. In La 9.67Si 5CoO 26 and La 10(Si/Ge) 5CoO 26.5 reduction of Co occurs as a competing process, favouring lower levels of nitride-oxide substitution.

Design of epoxy-functionalized Fe3O4@MCM-41 core-shell nanoparticles for enzyme immobilization.

PubMed

Ulu, Ahmet; Ozcan, Imren; Koytepe, Suleyman; Ates, Burhan

2018-05-01

The scope of our research was to prepare the organosilane-modified Fe 3 O 4 @MCM-41 core-shell magnetic nanoparticles, used for L-ASNase immobilization and explored screening of immobilization conditions such as pH, temperature, thermal stability, kinetic parameters, reusability and storage stability. In this content, Fe 3 O 4 core-shell magnetic nanoparticles were prepared via co-precipitation method and coated with MCM-41. Then, Fe 3 O 4 @MCM-41 magnetic nanoparticles were functionalized by (3-glycidyloxypropyl) trimethoxysilane (GPTMS) as an organosilane compound. Subsequently, L-ASNase was covalently immobilized on epoxy-functionalized Fe 3 O 4 @MCM-41 magnetic nanoparticles. The immobilized L-ASNase had greater activity at high pH and temperature values. It also maintained >92% of the initial activity after incubation at 55 °C for 3 h. Regarding kinetic values, immobilized L-ASNase showed a higher Vmax and lower Km compared to native L-ASNase. In addition, it displayed excellent reusability for 12 successive cycles. After 30 days of storage at 4 °C and 25 °C, immobilized L-ASNase retained 54% and 26% of its initial activities while native L-ASNase lost about 68% and 84% of its initial activity, respectively. As a result, the immobilization of L-ASNase onto magnetic nanoparticles may provide an advantage in terms of removal of L-ASNase from reaction media. Copyright © 2018. Published by Elsevier B.V.

Flexible, planar-integrated, all-solid-state fiber supercapacitors with an enhanced distributed-capacitance effect.

PubMed

Liu, Bin; Tan, Dongsheng; Wang, Xianfu; Chen, Di; Shen, Guozhen

2013-06-10

Flexible and highly efficient energy storage units act as one of the key components in portable electronics. In this work, by planar-integrated assembly of hierarchical ZnCo₂O₄ nanowire arrays/carbon fibers electrodes, a new class of flexible all-solid-state planar-integrated fiber supercapacitors are designed and produced via a low-cost and facile method. The as-fabricated flexible devices exhibit high-efficiency, enhanced capacity, long cycle life, and excellent electrical stability. An enhanced distributed-capacitance effect is experimentally observed for the device. This strategy enables highly flexible new structured supercapacitors with maximum functionality and minimized size, thus making it possible to be readily applied in flexible/portable photoelectronic devices. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fe-Catalyzed Synthesis of Porous Carbons Spheres with High Graphitization Degree for High-Performance Supercapacitors

NASA Astrophysics Data System (ADS)

Zhu, Jun; Shi, Hongwei; Zhuo, Xin; Hu, Yalin

2017-10-01

We have developed a facile and efficient Fe-catalyzed method for fabrication of porous carbons spheres with high graphitization degree (GNPCs) using glucose as carbon precursor at relatively low carbonization temperature. GNPCs not only have relatively large accessible ion surface area to accommodate greater capacity but also high graphitization degree to accelerate ion diffusion. As a typical application, we demonstrate that GNPCs exhibit excellent electrochemical performance for use in supercapacitors, with high specific capacity of 150.6 F g-1 at current density of 1 A g-1 and good rate capability and superior cycling stability over 10,000 cycles, confirming their potential application for energy storage. Moreover, it is believed that this method offers a new strategy for synthesis of porous carbons with high graphitization degree.

Facile and Eco-Friendly Synthesis of Finger-Like Co3O4 Nanorods for Electrochemical Energy Storage

PubMed Central

Sun, Shijiao; Zhao, Xiangyu; Yang, Meng; Ma, Liqun; Shen, Xiaodong

2015-01-01

Co3O4 nanorods were prepared by a facile hydrothermal method. Eco-friendly deionized water rather than organic solvent was used as the hydrothermal media. The as-prepared Co3O4 nanorods are composed of many nanoparticles of 30–50 nm in diameter, forming a finger-like morphology. The Co3O4 electrode shows a specific capacitance of 265 F g−1 at 2 mV s−1 in a supercapacitor and delivers an initial specific discharge capacity as high as 1171 mAh g−1 at a current density of 50 mA g−1 in a lithium ion battery. Excellent cycling stability and electrochemical reversibility of the Co3O4 electrode were also obtained. PMID:28347124

Characterization of Qatar's surface carbonates for CO2 capture and thermochemical energy storage

NASA Astrophysics Data System (ADS)

Kakosimos, Konstantinos E.; Al-Haddad, Ghadeer; Sakellariou, Kyriaki G.; Pagkoura, Chrysa; Konstandopoulos, Athanasios G.

2017-06-01

Samples of surface carbonates were collected from three different areas of the Qatar peninsula. We employed material characterization techniques to examine the morphology and composition of the samples, while their CO2 capture capacity was assessed via multiple successive calcination-carbonation cycles. Our samples were mainly calcite and dolomite based. Calcite samples showed higher initial capacity of around 11 mmol CO2 g-1 which decayed rapidly to less than 2 mmol CO2 g-1. On the other hand, dolomite samples showed an excellent stability (˜15 cycles) with a capacity of 6 mmol CO2 g-1. The performance of the dolomite samples is better compared to other similar natural samples, from literature. A promising result for future studies towards improving their performance by physical and chemical modification.

Powering up the future: radical polymers for battery applications.

PubMed

Janoschka, Tobias; Hager, Martin D; Schubert, Ulrich S

2012-12-18

Our society's dependency on portable electric energy, i.e., rechargeable batteries, which permit power consumption at any place and in any time, will eventually culminate in resource wars on limited commodities like lithium, cobalt, and rare earth metals. The substitution of conventional metals as means of electric charge storage by organic and polymeric materials, which may ultimately be derived from renewable resources, appears to be the only feasible way out. In this context, the novel class of organic radical batteries (ORBs) excelling in rate capability (i.e., charging speed) and cycling stability (>1000 cycles) sets new standards in battery research. This review examines stable nitroxide radical bearing polymers, their processing to battery systems, and their promising performance. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Instability risk analysis and risk assessment system establishment of underground storage caverns in bedded salt rock

NASA Astrophysics Data System (ADS)

Jing, Wenjun; Zhao, Yan

2018-02-01

Stability is an important part of geotechnical engineering research. The operating experiences of underground storage caverns in salt rock all around the world show that the stability of the caverns is the key problem of safe operation. Currently, the combination of theoretical analysis and numerical simulation are the mainly adopts method of reserve stability analysis. This paper introduces the concept of risk into the stability analysis of underground geotechnical structure, and studies the instability of underground storage cavern in salt rock from the perspective of risk analysis. Firstly, the definition and classification of cavern instability risk is proposed, and the damage mechanism is analyzed from the mechanical angle. Then the main stability evaluating indicators of cavern instability risk are proposed, and an evaluation method of cavern instability risk is put forward. Finally, the established cavern instability risk assessment system is applied to the analysis and prediction of cavern instability risk after 30 years of operation in a proposed storage cavern group in the Huai’an salt mine. This research can provide a useful theoretical base for the safe operation and management of underground storage caverns in salt rock.

Performance of Partially Exfoliated Nitrogen-Doped Carbon Nanotubes Wrapped with Hierarchical Porous Carbon in Electrolytes.

PubMed

Mangisetti, Sandhya Rani; Pari, Baraneedharan; M, Kamaraj; Ramaprabhu, Sundara

2018-05-25

The preparation of highly conductive, high-surface-area, heteroatom-doped, porous carbon nanocomposite materials with enhanced electrochemical performance for sustainable energy-storage technologies, such as supercapacitors, is challenging. Herein, a route for the large-scale synthesis of nitrogen-doped porous carbon wrapped partially exfoliated carbon nanotubes (N-PPECNTs) with an interconnected hierarchical porous structure, as an advanced electrode material that can realize several potential applications for energy storage, is presented. Polypyrrole conductive polymer acts as both nitrogen and carbon sources that contribute to the pseudocapacitance. Partially exfoliated carbon nanotubes (PECNTs) provide a high specific surface area for ion and charge transportation and act as a conductive matrix. The derived porous N-PPECNT displays a nitrogen content of 6.95 at %, with a specific surface area of 2050 m 2  g -1 , and pore volume of 1.13 cm 3  g -1 . N-PPECNTs, as an electrode material for supercapacitors, exhibit an excellent specific capacitance of 781 F g -1 at 2 A g -1 , with a high cycling stability of 95.3 % over 10 000 cycles. Furthermore, the symmetric supercapacitor exhibits remarkable energy densities as high as 172.8, 62.7, and 53.55 Wh kg -1 in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([BMIM][TFSI]), organic, and aqueous electrolytes, respectively. Also, biocompatible hydrogel and polymer gel electrolyte based, stable, flexible supercapacitors with excellent electrochemical performance could be demonstrated. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of techniques for stabilizing hemoglobins of rainbow trout (Salmo gairdneri) during frozen storage

USGS Publications Warehouse

Reinitz, G.L.

1976-01-01

1. The stability of hemoglobin of rainbow trout under frozen conditions in oxyform, carboxyform, and cyanometform was examined.2. Carboxyhemoglobin retained its original electrophoretic banding pattern after 14 days of frozen storage, whereas oxyform and cyanometform hemoglobins did not.3. Banding patterns changed in some samples in all treatment groups after 21 days of storage.

Effect of Storage Time and Temperature on Dimensional Stability of Impressions Made with Zinc Oxide Impression Paste

PubMed Central

Habibzadeh, Sareh; Safaeian, Shima; Behruzibakhsh, Marjan; Kaviyani, Parisa; Kharazifard, Mohamadjavad

2016-01-01

Objectives: This study aimed to assess the effect of storage time and temperature on dimensional stability of impressions made with Cavex Outline zinc oxide impression paste. Materials and Methods: A round stainless steel mold with five grooves (three horizontal and two vertical) was used in this in-vitro experimental study. Cavex Outline impression paste was prepared according to the manufacturer’s instructions and applied to the mold. The mold was placed on a block and stored at 35°C and 100% humidity for setting. The impressions were poured with stone immediately and also after 30, 120, 240 and 420 minutes and 24 hours. The distance between the vertical lines on the casts was measured and compared with that in the immediately poured cast. Results: Storage in a refrigerator and at room temperature for zero to seven hours had no significant effect on dimensional stability of the impressions; however, 24 hours of storage in a refrigerator or at room temperature decreased the dimensional stability of Cavex Outline (P=0.001). Also, a significant association was found between dimensional changes following 24 hours of storage in a refrigerator (4°C) and at room temperature (23°C; P<0.01). Conclusions: The optimal pouring time of Cavex Outline impressions with stone is between zero to seven hours, and 24 hours of storage significantly decreases the dimensional stability. PMID:28392816

Ultrathin Mesoporous RuCo2 O4 Nanoflakes: An Advanced Electrode for High-Performance Asymmetric Supercapacitors.

PubMed

Dubal, Deepak P; Chodankar, Nilesh R; Holze, Rudolf; Kim, Do-Heyoung; Gomez-Romero, Pedro

2017-04-22

A new ruthenium cobalt oxide (RuCo 2 O 4 ) with a unique marigold-like nanostructure and excellent performance as an advanced electrode material has been successfully prepared by a simple electrodeposition (potentiodynamic mode) method. The RuCo 2 O 4 marigolds consist of numerous clusters of ultrathin mesoporous nanoflakes, leaving a large interspace between them to provide numerous electrochemically active sites. Strikingly, this unique marigold-like nanostructure provided excellent electrochemical performance in terms of high energy-storage capacitance (1469 F g -1 at 6 A g -1 ) with excellent rate proficiency and long-lasting operating cycling stability (ca. 91.3 % capacitance retention after 3000 cycles), confirming that the mesoporous nanoflakes participate in the ultrafast electrochemical reactions. Furthermore, an asymmetric supercapacitor was assembled using RuCo 2 O 4 (positive electrode) and activated carbon (negative electrode) with aqueous KOH electrolyte. The asymmetric design allowed an upgraded potential range of 1.4 V, which further provided a good energy density of 32.6 Wh kg -1 (1.1 mWh cm -3 ). More importantly, the cell delivered an energy density of 12.4 Wh kg -1 even at a maximum power density of 3.2 kW kg -1 , which is noticeably superior to carbon-based symmetric systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrahigh-power supercapacitors based on highly conductive graphene nanosheet/nanometer-sized carbide-derived carbon frameworks.

PubMed

Yan, Pengtao; Zhang, Xuesha; Hou, Meiling; Liu, Yanyan; Liu, Ting; Liu, Kang; Zhang, Ruijun

2018-06-22

In order to develop energy storage devices with high power performance, electrodes should hold well-defined pathways for efficient ionic and electronic transport. Herein, we demonstrate a highly conductive graphene nanosheet/nanometer-sized carbide-derived carbon framework (hcGNS/nCDC). In this architecture, nCDC possesses short transport paths for electrolyte ions, thus ensuring the rapid ions transportation. The excellent electrical conductivity of hcGNS can reduce the electrode internal resistance for the supercapacitor and thus endows the hcGNS/nCDC composite electrodes with excellent electronic transportation performance. Electrochemical measurements show that the cyclic voltammogram of hcGNS/nCDC can maintain a rectangular-like shape with the increase of the scan rate from 5 mV s -1 to 20 V s -1 , and the specific capacitance retention is up to 51% even at a high scan rate of 20 V s -1 , suggesting ultrahigh power performance, which, to the best of our knowledge, is among the best power performances reported so far for the carbon materials. Furthermore, the hcGNS/nCDC composite also shows an excellent cycling stability (no drop in its capacitance occurs even after 10000 cycles). This work demonstrates the advantage in the ultrahigh power performance for the framework having both short transport pathways for electrolyte ions and high electrical conductivity.

Ultrahigh-power supercapacitors based on highly conductive graphene nanosheet/nanometer-sized carbide-derived carbon frameworks

NASA Astrophysics Data System (ADS)

Yan, Pengtao; Zhang, Xuesha; Hou, Meiling; Liu, Yanyan; Liu, Ting; Liu, Kang; Zhang, Ruijun

2018-06-01

In order to develop energy storage devices with high power performance, electrodes should hold well-defined pathways for efficient ionic and electronic transport. Herein, we demonstrate a highly conductive graphene nanosheet/nanometer-sized carbide-derived carbon framework (hcGNS/nCDC). In this architecture, nCDC possesses short transport paths for electrolyte ions, thus ensuring the rapid ions transportation. The excellent electrical conductivity of hcGNS can reduce the electrode internal resistance for the supercapacitor and thus endows the hcGNS/nCDC composite electrodes with excellent electronic transportation performance. Electrochemical measurements show that the cyclic voltammogram of hcGNS/nCDC can maintain a rectangular-like shape with the increase of the scan rate from 5 mV s‑1 to 20 V s‑1, and the specific capacitance retention is up to 51% even at a high scan rate of 20 V s‑1, suggesting ultrahigh power performance, which, to the best of our knowledge, is among the best power performances reported so far for the carbon materials. Furthermore, the hcGNS/nCDC composite also shows an excellent cycling stability (no drop in its capacitance occurs even after 10000 cycles). This work demonstrates the advantage in the ultrahigh power performance for the framework having both short transport pathways for electrolyte ions and high electrical conductivity.

A Flexible Stretchable Hydrogel Electrolyte for Healable All-in-One Configured Supercapacitors.

PubMed

Guo, Ying; Zheng, Kaiqiang; Wan, Pengbo

2018-04-01

The development of integrated high-performance supercapacitors with all-in-one configuration, excellent flexibility and autonomously intrinsic self-healability, and without the extra healable film layers, is still tremendously challenging. Compared to the sandwich-like laminated structures of supercapacitors with augmented interfacial contact resistance, the flexible healable integrated supercapacitor with all-in-one structure could theoretically improve their interfacial contact resistance and energy densities, simplify the tedious device assembly process, prolong the lifetime, and avoid the displacement and delamination of multilayered configurations under deformations. Herein, a flexible healable all-in-one configured supercapacitor with excellent flexibility and reliable self-healing ability by avoiding the extra healable film substrates and the postassembled sandwich-like laminated structures is developed. The healable all-in-one configured supercapacitor is prepared from in situ polymerization and deposition of nanocomposites electrode materials onto the two-sided faces of the self-healing hydrogel electrolyte separator. The self-healing hydrogel film is obtained from the physically crosslinked hydrogel with enormous hydrogen bonds, which can endow the healable capability through dynamic hydrogen bonding. The assembled all-in-one configured supercapacitor exhibits enhanced capacitive performance, good cycling stability, reliable self-healing capability, and excellent flexibility. It holds broad prospects for obtaining various flexible healable all-in-one configured supercapacitors for working as portable energy storage devices in wearable electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controllable synthesis of CuS hollow microflowers hierarchical structures for asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Liu, Yanxia; Zhou, Zhaoxiao; Zhang, Shengping; Luo, Wenhao; Zhang, Guofeng

2018-06-01

One of the major challenges of high-performance asymmetric supercapacitors is engineering electrode materials with high capacitance and good cycling stability. Hence, we have successfully prepared different CuS hierarchical structures including CuS tubular structures (T-CuS), CuS hollow microspheres (S-CuS) and CuS hollow microflowers (H-CuS) by adjusting the solvents, all of which are investigated as electrode materials for supercapacitors. Among them, the H-CuS electrode exhibits the best electrochemical performance involving a high capacitance of 536.7 F g-1 at a current density of 8 A g-1 and excellent cycling stability with 83.6% capacitance retention for 20,000 continuous cycles at a current density of 5 A g-1. In addition, an asymmetric supercapacitor has assembled with H-CuS as positive electrode and activated carbon (AC) as negative electrode, which exhibits a desirable energy density of 15.97 W h kg-1 when the power density is 185.4 W kg-1. These desirable electrochemical performances powerfully demonstrate that the H-CuS electrode has promising potential for applications in energy storage fields.

Nonlinear optical polymers for electro-optic signal processing

NASA Technical Reports Server (NTRS)

Lindsay, Geoffrey A.

1991-01-01

Photonics is an emerging technology, slated for rapid growth in communications systems, sensors, imagers, and computers. Its growth is driven by the need for speed, reliability, and low cost. New nonlinear polymeric materials will be a key technology in the new wave of photonics devices. Electron-conjubated polymeric materials offer large electro-optic figures of merit, ease of processing into films and fibers, ruggedness, low cost, and a plethora of design options. Several new broad classes of second-order nonlinear optical polymers were developed at the Navy's Michelson Laboratory at China Lake, California. Polar alignment in thin film waveguides was achieved by electric-field poling and Langmuir-Blodgett processing. Our polymers have high softening temperatures and good aging properties. While most of the films can be photobleached with ultraviolet (UV) light, some have excellent stability in the 500-1600 nm range, and UV stability in the 290-310 nm range. The optical nonlinear response of these polymers is subpicosecond. Electro-optic switches, frequency doublers, light modulators, and optical data storage media are some of the device applications anticipated for these polymers.

Preparation and characterization of novel anion phase change heat storage materials.

PubMed

Hong, Wei; Lil, Qingshan; Sun, Jing; Di, Youbo; Zhao, Zhou; Yu, Wei'an; Qu, Yuan; Jiao, TiFeng; Wang, Guowei; Xing, Guangzhong

2013-10-01

In this paper, polyurethane phase change material was successfully prepared with TDI with BDO for hard segments and PEG for soft segments. Moreover, based on this the solid-solid phase change material, A-PCM1030 which can release anions was prepared with the successful addition of anion additives A1030 for the first time. Then the test of the above material was conducted utilizing FT-IR, DSC, TEM, WAXD and Air Ion Detector. The Results indicated that the polyurethane phase change material possesses excellent thermal stability since there was no appearance of liquid leakage and phase separation after 50 times warming-cooling thermal cycles. It also presented reversibility on absorbing and releasing heat. In addition, adding a little A1030 can increase the thermal stability and reduce phase transition temperatures, as well as reduce the undercooling of the polyurethane phase change material. In addition, the anion test results suggested that the supreme amount of anion released by A-PCM1030 could reach 2510 anions/cm3 under dynamic conditions, which is beneficial for human health.

Fabrication of wound capacitors using flexible alkali-free glass

DOE PAGES

Wilke, Rudeger H. T.; Baker, Amanda; Brown-Shaklee, Harlan; ...

2016-10-01

Here, alkali-free glasses, which exhibit high energy storage densities (~35 J/cc), present a unique opportunity to couple high temperature stability with high breakdown strength, and thus provide an avenue for capacitor applications with stringent temperature and power requirements. Realizing the potential of these materials in kilovolt class capacitors with >1 J/cc recoverable energy density requires novel packaging strategies that incorporate these extremely fragile dielectrics. In this paper, we demonstrate the feasibility of fabricating wound capacitors using 50-μm-thick glass. Two capacitors were fabricated from 2.8-m-long ribbons of thin (50 μm) glass wound into 125-140-mm-diameter spools. The capacitors exhibit a capacitance ofmore » 70-75 nF with loss tangents below 1%. The wound capacitors can operate up to 1 kV and show excellent temperature stability to 150 °C. By improving the end terminations, the self-resonance can be shifted to above 1 MHz, indicating that these materials may be useful for pulsed power applications with microsecond discharge times.« less

Improved Performance of Ionic Liquid Supercapacitors by using Tetracyanoborate Anions

PubMed Central

Martins, Vitor L.; Rennie, Anthony J. R.; Sanchez‐Ramirez, Nedher; Torresi, Roberto M.; Hall, Peter J.

2018-01-01

Abstract Supercapacitors are energy storage devices designed to operate at higher power densities than conventional batteries, but their energy density is still too low for many applications. Efforts are made to design new electrolytes with wider electrochemical windows than aqueous or conventional organic electrolytes in order to increase energy density. Ionic liquids (ILs) with wide electrochemical stability windows are excellent candidates to be employed as supercapacitor electrolytes. ILs containing tetracyanoborate anions [B(CN)4] offer wider electrochemical stability than conventional electrolytes and maintain a high ionic conductivity (6.9 mS cm−1). Herein, we report the use of ILs containing the [B(CN)4] anion for such an application. They presented a high maximum operating voltage of 3.7 V, and two‐electrode devices demonstrate high specific capacitances even when operating at relatively high rates (ca. 20 F g−1 @ 15 A g−1). This supercapacitor stored more energy and operated at a higher power at all rates studied when compared with cells using a commonly studied ILs. PMID:29577008

Critical role of intercalated water for electrocatalytically active nitrogen-doped graphitic systems

DOE PAGES

Martinez, Ulises; Dumont, Joseph H.; Holby, Edward F.; ...

2016-03-18

Graphitic materials are very essential in energy conversion and storage because of their excellent chemical and electrical properties. The strategy for obtaining functional graphitic materials involves graphite oxidation and subsequent dissolution in aqueous media, forming graphene-oxide nanosheets (GNs). Restacked GNs contain substantial intercalated water that can react with heteroatom dopants or the graphene lattice during reduction. We demonstrate that removal of intercalated water using simple solvent treatments causes significant structural reorganization, substantially affecting the oxygen reduction reaction (ORR) activity and stability of nitrogen-doped graphitic systems. Amid contrasting reports describing the ORR activity of GN-based catalysts in alkaline electrolytes, we demonstratemore » superior activity in an acidic electrolyte with an onset potential of ~0.9 V, a half-wave potential (E ½) of 0.71 V, and a selectivity for four-electron reduction of >95%. Finally and further, durability testing showed E ½ retention >95% in N 2- and O 2-saturated solutions after 2000 cycles, demonstrating the highest ORR activity and stability reported to date for GN-based electrocatalysts in acidic media.« less

A Novel Layered Sedimentary Rocks Structure of the Oxygen-Enriched Carbon for Ultrahigh-Rate-Performance Supercapacitors.

PubMed

Zhang, Lin-Lin; Li, Huan-Huan; Shi, Yan-Hong; Fan, Chao-Ying; Wu, Xing-Long; Wang, Hai-Feng; Sun, Hai-Zhu; Zhang, Jing-Ping

2016-02-17

In this paper, gelatin as a natural biomass was selected to successfully prepare an oxygen-enriched carbon with layered sedimentary rocks structure, which exhibited ultrahigh-rate performance and excellent cycling stability as supercapacitors. The specific capacitance reached 272.6 F g(-1) at 1 A g(-1) and still retained 197.0 F g(-1) even at 100 A g(-1) (with high capacitance retention of 72.3%). The outstanding electrochemical performance resulted from the special layered structure with large surface area (827.8 m(2) g(-1)) and high content of oxygen (16.215 wt %), which effectively realized the synergistic effects of the electrical double-layer capacitance and pseudocapacitance. Moreover, it delivered an energy density of 25.3 Wh kg(-1) even with a high power density of 34.7 kW kg(-1) and ultralong cycling stability (with no capacitance decay even over 10,000 cycles at 2 A g(-1)) in a symmetric supercapacitor, which are highly desirable for their practical application in energy storage devices and conversion.

Immobilization of pectinase onto chitosan magnetic nanoparticles by macromolecular cross-linker.

PubMed

Sojitra, Uttam V; Nadar, Shamraja S; Rathod, Virendra K

2017-02-10

Pectinase was immobilized onto chitosan magnetic nanoparticles (CMNPs) by dextran polyaldehyde as a macromolecular cross-linking agent. The parameters like cross-linking concentration, time and CMNPs to enzyme ratio were optimized. Further, prepared magnetic pectinase nanobiocatalyst was characterized by FT-IR and XRD. The thermal kinetic studies for immobilized pectinase showed two folds improved thermal stability in the range of 55-75°C as compared to free form. The V max and K m values of immobilized pectinase were found to be nearly equal to native form which indicated that conformational flexibility of pectinase was retained even after immobilization. The residual activity of immobilized pectinase was 85% after seven successive cycles of reuse, while it retained upto 89% residual activity on storage of fifteen days which exhibited excellent stability and durability. The conformational changes in pectinase after immobilization were evaluated by FT-IR spectroscopy data analysis tools. Finally, magnetic pectinase nanobiocatalyst was employed for apple juice clarification which showed turbidity reduction upto 74% after 150min treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microscale Enhancement of Heat and Mass Transfer for Hydrogen Energy Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drost, Kevin; Jovanovic, Goran; Paul, Brian

2015-09-30

The document summarized the technical progress associated with OSU’s involvement in the Hydrogen Storage Engineering Center of Excellence. OSU focused on the development of microscale enhancement technologies for improving heat and mass transfer in automotive hydrogen storage systems. OSU’s key contributions included the development of an extremely compact microchannel combustion system for discharging hydrogen storage systems and a thermal management system for adsorption based hydrogen storage using microchannel cooling (the Modular Adsorption Tank Insert or MATI).

Methacrylate-Stitched β-Cyclodextrin Embedded with Nanogold/Nanotitania: A Skin Adhesive Device for Enhanced Transdermal Drug Delivery.

PubMed

Anirudhan, T S; Nair, Syam S; Sasidharan, Athira V

2017-12-27

Transdermal (TD) drug delivery is a more attractive technique for drug delivery compared to oral and intravenous injection. However, the permeation of drug molecules across the skin is difficult due to the presence of highly ordered lipid barrier. This study details the development of a novel TD system, which has the potential to simultaneously enhance the skin permeability and adhesion behavior. Ibuprofen (IP) was selected as model drug. The ability of gold nanoparticle (AuNP) and hydrophobic titanium nanotube (TNT) to enhance the skin permeability was explored. Additionally, β-cyclodextrin (βCD), which can exceptionally encapsulate poorly water-soluble drugs, is grafted with methacrylates to improve the skin adhesion property. Finally, Au-TNT nanocomposite was deposited onto methacrylate-grafted βCD matrix. The developed material was characterized through NMR spectroscopy, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The characteristics of the film, including water vapor permeability (WVP), thermomechanical properties, etc., were examined in terms of Au-TNT content. The TD delivery of IP with different concentrations of Au-TNT was evaluated via an in vitro skin permeation study through rat skin. It is revealed that the prepared TD film exhibited an improved drug-delivery performance due to the synergistic action of AuNP and hydrophobic TNT. The cumulative percent of IP delivered across the skin is extremely depending on nanofiller content, lipophilicity, and thickness of the membrane, and the device incorporated with 4.0% Au-TNT displayed the best performance. In addition, a study on storage stability was performed by storing the films for 2 months at different temperatures. The study revealed that the device possessed excellent storage stability when stored at low temperature. The developed film offers excellent WVP, drug encapsulation efficiency, thermomechanical properties, and skin adhesion behavior. Moreover, the device was cosmetically attractive, noncytotoxic, and resistant to microbial growth and hence extremely reliable for skin application. The developed skin permeation strategy may open new avenues in TD drug delivery.

Enhanced Stability of Inactivated Influenza Vaccine Encapsulated in Dissolving Microneedle Patches

PubMed Central

Chu, Leonard Y.; Ye, Ling; Dong, Ke; Compans, Richard W.; Yang, Chinglai; Prausnitz, Mark R.

2015-01-01

Purpose This study tested the hypothesis that encapsulation of influenza vaccine in microneedle patches increases vaccine stability during storage at elevated temperature. Methods Whole inactivated influenza virus vaccine (A/Puerto Rico/8/34) was formulated into dissolving microneedle patches and vaccine stability was evaluated by in vitro and in vivo assays of antigenicity and immunogenicity after storage for up to 3 months at 4, 25, 37 and 45°C. Results While liquid vaccine completely lost potency as determined by hemagglutination (HA) activity within 1–2 weeks outside of refrigeration, vaccine in microneedle patches lost 40–50% HA activity during or shortly after fabrication, but then had no significant additional loss of activity over 3 months of storage, independent of temperature. This level of stability required reduced humidity by packaging with desiccant, but was not affected by presence of oxygen. This finding was consistent with additional stability assays, including antigenicity of the vaccine measured by ELISA, virus particle morphological structure captured by transmission electron microscopy and protective immune responses by immunization of mice in vivo. Conclusions These data show that inactivated influenza vaccine encapsulated in dissolving microneedle patches has enhanced stability during extended storage at elevated temperatures. PMID:26620313

Enhanced mucosal immune responses against tetanus toxoid using novel delivery system comprised of chitosan-functionalized gold nanoparticles and botanical adjuvant: characterization, immunogenicity, and stability assessment.

PubMed

Barhate, Ganesh; Gautam, Manish; Gairola, Sunil; Jadhav, Suresh; Pokharkar, Varsha

2014-11-01

Approaches based on combined use of delivery systems and adjuvants are being favored to maximize efficient mucosal delivery of antigens. Here, we describe a novel delivery system comprised of chitosan-functionalized gold nanoparticles (CsAuNPs) and saponin-containing botanical adjuvant; Asparagus racemosus extract (ARE) for oral delivery of tetanus toxoid (TT). A significant increase in TT-specific IgG (34.53-fold) and IgA (43.75-fold) was observed when TT-CsAuNPs were formulated with ARE (TT-ARE-CsAuNPs). The local IgA immune responses for TT also showed a significant increase (106.5-fold in intestine washes and 99.74-fold in feces) with ARE-based formulations as compared with plain TT group. No effect of ARE was observed on size, charge, and loading properties of CsAuNPs. Additionally, no effect of ARE and CsAuNPs was observed on antigenicity and secondary structure of TT as determined by fluorescence, circular dichroism, and Fourier transform infrared spectroscopy. The stability studies demonstrated excellent stability profile of formulation at recommended storage conditions. The study establishes the possible role of immunomodulatory adjuvants in particulate delivery systems for mucosal delivery of vaccines. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Improved energy storage, magnetic and electrical properties of aligned, mesoporous and high aspect ratio nanofibers of spinel-NiMn2O4

NASA Astrophysics Data System (ADS)

Bhagwan, Jai; Rani, Stuti; Sivasankaran, V.; Yadav, K. L.; Sharma, Yogesh

2017-12-01

Spinel-NiMn2O4 (NMO) nanofibers of high aspect ratio, high surface area (50 m2 g-1) and homogeneous pore size distribution are fabricated by electrospinning process and characterized by XRD, FTIR, XPS, BET, FESEM, TEM techniques. Further, multifunctional properties (energy storage properties, magnetic and electrical properties) of NMO nanofibers are also examined. High specific capacitance (Cs) of 410 (±5) F g-1 at 1 A g-1, good rate capability and high cycling stability (up to 5000 cycles) are demonstrated by NMO nanofibers. Furthermore, NMO-based solid-state symmetric supercapacitor (SSSC) shows a high Cs of 170 (±5) F g-1 at 0.5 A g-1 in potential range of 0.0V-2.0 V and exhibits excellent energy density of ∼95 W h kg-1 and power density of 1030 W Kg-1. The above storage properties i.e. high energy density and output voltage of 2.0 V are further supplemented by lighting up a red colored LED (1.8 V @ current 20 mA) at least for 5 min. The ionic diffusion coefficient of NMO based electrode is found to be ∼4.84 × 10-11 cm2 s-1. Magnetic and dielectric properties of NMO nanofibers are also examined and results are discussed.

Directly Grown Nanostructured Electrodes for High Volumetric Energy Density Binder-Free Hybrid Supercapacitors: A Case Study of CNTs//Li4Ti5O12

NASA Astrophysics Data System (ADS)

Zuo, Wenhua; Wang, Chong; Li, Yuanyuan; Liu, Jinping

2015-01-01

Hybrid supercapacitor (HSC), which typically consists of a Li-ion battery electrode and an electric double-layer supercapacitor electrode, has been extensively investigated for large-scale applications such as hybrid electric vehicles, etc. Its application potential for thin-film downsized energy storage systems that always prefer high volumetric energy/power densities, however, has not yet been explored. Herein, as a case study, we develop an entirely binder-free HSC by using multiwalled carbon nanotube (MWCNT) network film as the cathode and Li4Ti5O12 (LTO) nanowire array as the anode and study the volumetric energy storage capability. Both the electrode materials are grown directly on carbon cloth current collector, ensuring robust mechanical/electrical contacts and flexibility. Our 3 V HSC device exhibits maximum volumetric energy density of ~4.38 mWh cm-3, much superior to those of previous supercapacitors based on thin-film electrodes fabricated directly on carbon cloth and even comparable to the commercial thin-film lithium battery. It also has volumetric power densities comparable to that of the commercial 5.5 V/100 mF supercapacitor (can be operated within 3 s) and has excellent cycling stability (~92% retention after 3000 cycles). The concept of utilizing binder-free electrodes to construct HSC for thin-film energy storage may be readily extended to other HSC electrode systems.

Bulk Bismuth as a High-Capacity and Ultralong Cycle-Life Anode for Sodium-Ion Batteries by Coupling with Glyme-Based Electrolytes.

PubMed

Wang, Chenchen; Wang, Liubin; Li, Fujun; Cheng, Fangyi; Chen, Jun

2017-09-01

Sodium-ion batteries (SIBs) have attracted great interest for large-scale electric energy storage in recent years. However, anodes with long cycle life and large reversible capacities are still lacking and therefore limiting the development of SIBs. Here, a bulk Bi anode with surprisingly high Na storage performance in combination with glyme-based electrolytes is reported. This study shows that the bulk Bi electrode is gradually developed into a porous integrity during initial cycling, which is totally different from that in carbonate-based electrolytes and ensures facile Na + transport and structural stability. The achievable capacity of bulk Bi in the NaPF 6 -diglyme electrolyte is high up to 400 mAh g -1 , and the capacity retention is 94.4% after 2000 cycles, corresponding to a capacity loss of 0.0028% per cycle. It exhibits two flat discharge/charge plateaus at 0.67/0.77 and 0.46/0.64 V, ascribed to the typical two-phase reactions of Bi ↔ NaBi and NaBi ↔ Na 3 Bi, respectively. The excellent performance is attributed to the unique porous integrity, stable solid electrolyte interface, and good electrode wettability of glymes. This interplay between electrolyte and electrode to boost Na storage performance will pave a new pathway for high-performance SIBs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon-Confined SnO2-Electrodeposited Porous Carbon Nanofiber Composite as High-Capacity Sodium-Ion Battery Anode Material.

PubMed

Dirican, Mahmut; Lu, Yao; Ge, Yeqian; Yildiz, Ozkan; Zhang, Xiangwu

2015-08-26

Sodium resources are inexpensive and abundant, and hence, sodium-ion batteries are promising alternative to lithium-ion batteries. However, lower energy density and poor cycling stability of current sodium-ion batteries prevent their practical implementation for future smart power grid and stationary storage applications. Tin oxides (SnO2) can be potentially used as a high-capacity anode material for future sodium-ion batteries, and they have the advantages of high sodium storage capacity, high abundance, and low toxicity. However, SnO2-based anodes still cannot be used in practical sodium-ion batteries because they experience large volume changes during repetitive charge and discharge cycles. Such large volume changes lead to severe pulverization of the active material and loss of electrical contact between the SnO2 and carbon conductor, which in turn result in rapid capacity loss during cycling. Here, we introduce a new amorphous carbon-coated SnO2-electrodeposited porous carbon nanofiber (PCNF@SnO2@C) composite that not only has high sodium storage capability, but also maintains its structural integrity while ongoing repetitive cycles. Electrochemical results revealed that this SnO2-containing nanofiber composite anode had excellent electrochemical performance including high-capacity (374 mAh g(-1)), good capacity retention (82.7%), and large Coulombic efficiency (98.9% after 100th cycle).

Synthesis and characterization of β-Ni(OH)2 embedded with MgO and ZnO nanoparticles as nanohybrids for energy storage devices

NASA Astrophysics Data System (ADS)

Kumar, C. R. Ravi; Santosh, M. S.; Nagaswarupa, H. P.; Prashantha, S. C.; Yallappa, S.; Kumar, M. R. Anil

2017-06-01

In this study, the electrode material (nickel hydroxide powder) has been synthesized by a co-precipitation method using sodium hydroxide and nickel sulphate as precipitator and nickel source, respectively. The obtained nickel hydroxide powder has been subsequently embedded with biosynthesized MgO and ZnO nanoparticles as nanohybrids, which have been investigated as a novel hybrid electrode material for power-storage applications. The powder x-ray diffraction pattern of nickel hydroxide (Ni(OH)2)-based nanohybrid materials reveals a typical β-phase. Fourier transform infrared spectroscopy confirms the embedded structures of nanohybrids and thermal stability by thermogravimetry and differential thermal) analysis. The electrochemical properties of these materials have been studied using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The specific capacitance values are found to be 439, 1076, and 622 F g-1 for bare β-Ni(OH)2, and for β-Ni(OH)2 embedded with ZnO and MgO nanohybrids, respectively, at a scan rate of 10 mVs-1. The enhanced capacitance of nanohybrids is also evident from EIS measurements. Galvanostatic charge-discharge tests for these designed nanohybrids show excellent capacitance performance in battery and supercapacitor applications. These innovative results could be considered for the expansion of novel resources to scale for power-storage applications and may contribute to the development of this niche area at large.

Physicochemical Properties and Oxidative Storage Stability of Milled Roselle (Hibiscus sabdariffa L.) Seeds.

PubMed

Juhari, Nurul Hanisah; Petersen, Mikael Agerlin

2018-02-11

Milled Roselle ( Hibiscus sabdariffa L.) seeds of the UMKL cultivar were analyzed for proximate composition, water and oil absorption capacity, and the influence of storage conditions on storage stability. The storage stability was determined under four types of conditions: light/oxygen (air) (LO), light/nitrogen (LN), darkness/oxygen (air) (DO), and darkness/nitrogen (DN) while monitoring for seven consecutive months. During the storage period, the formation of volatiles was determined using dynamic headspace sampling and Gas Chromatography-Mass Spectrometry (GC-MS) analysis. In total, 85 volatiles were identified, mainly aldehydes, alcohols, ketones, furans, and acids indicating lipid oxidation. It is recommended that milled Roselle seeds should be flushed with nitrogen and stored in darkness. Under these conditions, the seeds can be stored for at least three months without changes in volatile profile. This is important to ensure the good quality of milled Roselle seeds for further commercialization.

Self-Assembled Three-Dimensional Graphene Macrostructures: Synthesis and Applications in Supercapacitors.

PubMed

Xu, Yuxi; Shi, Gaoquan; Duan, Xiangfeng

2015-06-16

Graphene and its derivatives are versatile building blocks for bottom-up assembly of advanced functional materials. In particular, with exceptionally large specific surface area, excellent electrical conductivity, and superior chemical/electrochemical stability, graphene represents the ideal material for various electrochemical energy storage devices including supercapacitors. However, due to the strong π-π interaction between graphene sheets, the graphene flakes tend to restack to form graphite-like powders when they are processed into practical electrode materials, which can greatly reduce the specific surface area and lead to inefficient utilization of the graphene layers for electrochemical energy storage. The self-assembly of two-dimensional graphene sheets into three-dimensional (3D) framework structures can largely retain the unique properties of individual graphene sheets and has recently garnered intense interest for fundamental investigations and potential applications in diverse technologies. In this Account, we review the recent advances in preparing 3D graphene macrostructures and exploring them as a unique platform for supercapacitor applications. We first describe the synthetic strategies, in which reduction of a graphene oxide dispersion above a certain critical concentration can induce the reduced graphene oxide sheets to cross-link with each other via partial π-π stacking interactions to form a 3D interconnected porous macrostructure. Multiple reduction strategies, including hydrothermal/solvothermal reduction, chemical reduction, and electrochemical reduction, have been developed for the preparation of 3D graphene macrostructures. The versatile synthetic strategies allow for easy incorporation of heteroatoms, carbon nanomaterials, functional polymers, and inorganic nanostructures into the macrostructures to yield diverse composites with tailored structures and properties. We then summarize the applications of the 3D graphene macrostructures for high-performance supercapacitors. With a unique framework structure in which the graphene sheets are interlocked in 3D space to prevent their restacking, the graphene macrostructures feature very high specific surface areas, rapid electron and ion transport, and superior mechanical strength. They can thus be directly used as supercapacitor electrodes with excellent specific capacitances, rate capabilities, and cycling stabilities. We finally discuss the current challenges and future opportunities in this research field. By regarding the graphene as both a single-atom-thick carbon sheet and a conjugated macromolecule, our work opens a new avenue to bottom-up self-assembly of graphene macromolecule sheets into functional 3D graphene macrostructures with remarkable electrochemical performances. We hope that this Account will promote further efforts toward fundamental investigation of graphene self-assembly and the development of advanced 3D graphene materials for their real-world applications in electrochemical energy storage devices and beyond.

Bacterial cellulose composites loaded with SiO2 nanoparticles: Dynamic-mechanical and thermal properties.

PubMed

Sheykhnazari, Somayeh; Tabarsa, Taghi; Ashori, Alireza; Ghanbari, Abbas

2016-12-01

The aim of this paper was to prepare composites of bacterial cellulose (BC) filled with silica (SiO 2 ) nanoparticles to evaluate the influence of the SiO 2 contents (3, 5 and 7wt%) on the thermo-mechanical properties of the composites. BC hydro-gel was immersed in an aqueous solution of silanol derived from tetraethoxysilane (TEOS), the silanol was then converted into SiO 2 in the BC matrix by pressing at 120°C and 2MPa. The BC/SiO 2 translucent sheets were examined by dynamic-mechanical analysis (DMA), thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM). The temperature dependence of the storage modulus, loss modulus and tan delta was determined by DMA. In general, the results revealed that the increment of storage modulus and thermal stability increased concomitantly with the augmentation of SiO 2 content. Therefore, it could be concluded that the mechanical properties of the composites were improved by using high amounts of nano silica. This would be a high aspect ratio of BC capable of connecting the BC matrix and SiO 2 , thereby enhancing a large contact surface and resulting in excellent coherence. A decrease of the storage modulus was consistent with increasing temperature, resulting from softening of the composites. The storage modulus of the composites increased in the order: BC/S7>BC/S5>BC/S3, while the loss modulus and tan delta decreased. On the other hand, the thermal stabilities of all BC/SiO 2 composites were remarkably enhanced as compared to the pristine BC. TGA curves showed that the temperature of decomposition of the pure BC gradually shifted from about 260°C to about 370°C as silica content increased. SEM observations illustrated that the nano-scale SiO 2 was embedded between the voids and nano-fibrils of the BC matrix. Overall, the results indicated that the successful synthesis and superior properties of BC/SiO 2 advocate its effectiveness for various applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Stability study of carboplatin infusion solutions in 0.9% sodium chloride in polyvinyl chloride bags.

PubMed

Myers, Alan L; Zhang, Yang-Ping; Kawedia, Jitesh D; Trinh, Van A; Tran, Huyentran; Smith, Judith A; Kramer, Mark A

2016-02-01

Carboplatin is a platinum-containing compound with efficacy against various malignancies. The physico-chemical stability of carboplatin in dextrose 5% water (D5W) has been thoroughly studied; however, there is a paucity of stability data in clinically relevant 0.9% sodium chloride infusion solutions. The manufacturer's limited stability data in sodium chloride solutions hampers the flexibility of carboplatin usage in oncology patients. Hence, the purpose of this study is to determine the physical and chemical stability of carboplatin-sodium chloride intravenous solutions under different storage conditions. The physico-chemical stability of 0.5 mg/mL, 2.0 mg/mL, and 4.0 mg/mL carboplatin-sodium chloride solutions prepared in polyvinyl chloride bags was determined following storage at room temperature under ambient fluorescent light and under refrigeration in the dark. Concentrations of carboplatin were measured at predetermined time points up to seven days using a stability-indicating high-performance liquid chromatography method. All tested solutions were found physically stable for at least seven days. The greatest chemical stability was observed under refrigerated storage conditions. At 4℃, all tested solutions were found chemically stable for at least seven days, with nominal losses of ≤6%. Following storage at room temperature exposed to normal fluorescent light, the chemical stability of 0.5 mg/mL, 2.0 mg/mL, and 4.0 mg/mL solutions was three days, five days, and seven days, respectively. The extended physico-chemical stability of carboplatin prepared in sodium chloride reported herein permits advance preparation of these admixtures, facilitating pharmacy utility and operations. Since no antibacterial preservative is contained within these carboplatin solutions, we recommend storage, when prepared under specified aseptic conditions, no greater than 24 h at room temperature or three days under refrigeration. © The Author(s) 2014.

Impact of Storage Conditions on the Stability of Predominant Phenolic Constituents and Antioxidant Activity of Dried Piper betle Extracts.

PubMed

Ali, Ameena; Chong, Chien Hwa; Mah, Siau Hui; Abdullah, Luqman Chuah; Choong, Thomas Shean Yaw; Chua, Bee Lin

2018-02-23

The phenolic constituents in Piper betle are well known for their antioxidant potential; however, current literature has very little information on their stability under the influence of storage factors. Present study evaluated the stability of total phenolic content (TPC) and antioxidant activity together with individual phenolic constituents (hydroxychavicol, eugenol, isoeugenol and allylpyrocatechol 3,4-diacetate) present in dried Piper betle 's extract under different storage temperature of 5 and 25 °C with and without light for a period of six months. Both light and temperature significantly influenced TPC and its corresponding antioxidant activity over time. More than 95% TPC and antioxidant activity was retained at 5 °C in dark condition after 180 days of storage. Hydroxychavicol demonstrated the best stability with no degradation while eugenol and isoeugenol displayed moderate stability in low temperature (5 °C) and dark conditions. 4-allyl-1,2-diacetoxybenzene was the only compound that underwent complete degradation. A new compound, 2,4-di- tert -butylphenol, was detected after five weeks of storage only in the extracts exposed to light. Both zero-order and first-order kinetic models were adopted to describe the degradation kinetics of the extract's antioxidant activity. Zero-order displayed better fit with higher correlation coefficients ( R ² = 0.9046) and the half-life was determined as 62 days for the optimised storage conditions (5 °C in dark conditions).

Accelerated decay rates drive soil organic matter persistence and storage in temperate forests via greater mineral stabilization of microbial residues.

NASA Astrophysics Data System (ADS)

Phillips, R.; Craig, M.; Turner, B. L.; Liang, C.

2017-12-01

Climate predicts soil organic matter (SOM) stocks at the global scale, yet controls on SOM stocks at finer spatial scales are still debated. A current hypothesis predicts that carbon (C) and nitrogen (N) storage in soils should be greater when decomposition is slow owing to microbial competition for nutrients or the recalcitrance of organic substrates (hereafter the `slow decay' hypothesis). An alternative hypothesis predicts that soil C and N storage should be greater in soils with rapid decomposition, owing to the accelerated production of microbial residues and their stabilization on soil minerals (hereafter the `stabilization hypothesis'). To test these alternative hypotheses, we quantified soil C and N to 1-m depth in temperate forests across the Eastern and Midwestern US that varied in their biotic, climatic, and edaphic properties. At each site, we sampled (1) soils dominated by arbuscular mycorrhizal (AM) tree species, which typically have fast decay rates and accelerated N cycling, (2) soils dominated by ectomycorrhizal (ECM) tree species, which generally have slow decay rates and slow N cycling, and (3) soils supporting both AM and ECM trees. To the extent that trees and theor associated microbes reflect and reinforce soil conditions, support for the slow decay hypothesis would be greater SOM storage in ECM soils, whereas support for the stabilization hypothesis would be greater SOM storage in AM soils. We found support for both hypotheses, as slow decomposition in ECM soils increased C and N storage in topsoil, whereas fast decomposition in AM soils increased C and N storage in subsoil. However, at all sites we found 57% greater total C and N storage in the entire profile in AM- soils (P < 0.0001), supporting the stabilization hypothesis. Amino sugar biomarkers (an indicator of microbial necromass) and particle size fractionation revealed that the greater SOM storage in AM soils was driven by an accumulation of microbial residues on clay minerals and metal oxides. Taken together, our results indicate that tree species influence soil C and N storage owing to how differences in decay rates affect mineral stabilization of organic matter. Further, our findings indicate that slow decay promotes soil C and N stocks at the soil surface, whereas fast decay promotes greater soil C and N stocks at depth.

In situ coating nickel organic complexes on free-standing nickel wire films for volumetric-energy-dense supercapacitors.

PubMed

Hong, Min; Xu, Shusheng; Yao, Lu; Zhou, Chao; Hu, Nantao; Yang, Zhi; Hu, Jing; Zhang, Liying; Zhou, Zhihua; Wei, Hao; Zhang, Yafei

2018-07-06

A self-free-standing core-sheath structured hybrid membrane electrodes based on nickel and nickel based metal-organic complexes (Ni@Ni-OC) was designed and constructed for high volumetric supercapacitors. The self-standing Ni@Ni-OC film electrode had a high volumetric specific capacity of 1225.5 C cm -3 at 0.3 A cm -3 and an excellent rate capability. Moreover, when countered with graphene-carbon nanotube (G-CNT) film electrode, the as-assembled Ni@Ni-OC//G-CNT hybrid supercapacitor device delivered an extraordinary volumetric capacitance of 85 F cm -3 at 0.5 A cm -3 and an outstanding energy density of 33.8 at 483 mW cm -3 . Furthermore, the hybrid supercapacitor showed no capacitance loss after 10 000 cycles at 2 A cm -3 , indicating its excellent cycle stability. These fascinating performances can be ascribed to its unique core-sheath structure that high capacity nano-porous nickel based metal-organic complexes (Ni-OC) in situ coated on highly conductive Ni wires. The impressive results presented here may pave the way to construct s self-standing membrane electrode for applications in high volumetric-performance energy storage.

Preparation of quantum dots CdTe decorated graphene composite for sensitive detection of uric acid and dopamine.

PubMed

Yu, Hong-Wei; Jiang, Jing-Hui; Zhang, Ze; Wan, Guang-Cai; Liu, Zhi-Yong; Chang, Dong; Pan, Hong-Zhi

2017-02-15

The assembly of quantum dots (QDs) in a simply method opens up opportunities to obtain access to the full potential of assembled QDs by virtue of the collective properties of the ensembles. In this study, quantum dots CdTe and graphene (Gr) nanocomposite was constructed for the simultaneous determination of uric acid (UA) and dopamine (DA). The CdTe QDs-Gr nanocomposite was prepared by ultrasonication and was characterized with microscopic techniques. The nanocomposite modified electrode was characterized by cyclicvoltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Due to the synergistic effects between CdTe QDs and Gr, the fabricated electrode exhibited excellent electrochemical catalytic activities, good biological compatibility and high sensitivity toward the oxidation of UA and DA. Under optimum conditions, in the co-existence system the linear calibration plots for UA and DA were obtained over the range of 3-600 μM and 1-500 μM with detection limits of 1.0 μM and 0.33 μM. The fabricated biosensor also exhibits the excellent repeatability, reproducibility, storage stability along with acceptable selectivity. Copyright © 2016. Published by Elsevier Inc.

Enabling high-rate electrochemical flow capacitors based on mesoporous carbon microspheres suspension electrodes

NASA Astrophysics Data System (ADS)

Tian, Meng; Sun, Yueqing; Zhang, Chuanfang (John); Wang, Jitong; Qiao, Wenming; Ling, Licheng; Long, Donghui

2017-10-01

Electrochemical flow capacitor (EFC) is a promising technology for grid energy storage, which combines the fast charging/discharging capability of supercapacitors with the scalable energy capacity of flow batteries. In this study, we report a high-power-density EFC using mesoporous carbon microspheres (MCMs) as suspension electrodes. By using a simple yet effective spray-drying technique, monodispersed MCMs with average particle size of 5 μm, high BET surface area of 1150-1267 m2 g-1, large pore volume of 2-4 cm3 g-1 and controllable mesopore size of 7-30 nm have been successfully prepared. The resultant MCMs suspension electrode shows excellent stability and considerable high capacitance of 100 F g-1 and good cycling ability (86% of initial capacitance after 10000 cycles). Specially, the suspension electrode exhibits excellent rate performance with 75% capacitance retention from 2 to 100 mV s-1, significantly higher than that of microporous carbon electrodes (20∼30%), due to the developed mesoporous channels facilitating for rapid ion diffusion. In addition, the electrochemical responses on both negative and positive suspension electrodes are studied, based on which an optimal capacitance matching between them is suggested for large-scale EFC unit.

Superior supercapacitors based on nitrogen and sulfur co-doped hierarchical porous carbon: Excellent rate capability and cycle stability

NASA Astrophysics Data System (ADS)

Zhang, Deyi; Han, Mei; Wang, Bing; Li, Yubing; Lei, Longyan; Wang, Kunjie; Wang, Yi; Zhang, Liang; Feng, Huixia

2017-08-01

Vastly improving the charge storage capability of supercapacitors without sacrificing their high power density and cycle performance would bring bright application prospect. Herein, we report a nitrogen and sulfur co-doped hierarchical porous carbon (NSHPC) with very superior capacitance performance fabricated by KOH activation of nitrogen and sulfur co-doped ordered mesoporous carbon (NSOMC). A high electrochemical double-layer (EDL) capacitance of 351 F g-1 was observed for the reported NSHPC electrodes, and the capacitance remains at 288 F g-1 even under a large current density of 20 A g-1. Besides the high specific capacitance and outstanding rate capability, symmetrical supercapacitor cell based on the NSHPC electrodes also exhibits an excellent cycling performance with 95.61% capacitance retention after 5000 times charge/discharge cycles. The large surface area caused by KOH activation (2056 m2 g-1) and high utilized surface area owing to the ideal micro/mesopores ratio (2.88), large micropores diameter (1.38 nm) and short opened micropores structure as well as the enhanced surface wettability induced by N and S heteroatoms doping and improved conductivity induced by KOH activation was found to be responsible for the very superior capacitance performance.

An Amorphous Carbon Nitride Composite Derived from ZIF-8 as Anode Material for Sodium-Ion Batteries.

PubMed

Fan, Jing-Min; Chen, Jia-Jia; Zhang, Qian; Chen, Bin-Bin; Zang, Jun; Zheng, Ming-Sen; Dong, Quan-Feng

2015-06-08

An composite comprising amorphous carbon nitride (ACN) and zinc oxide is derived from ZIF-8 by pyrolysis. The composite is a promising anode material for sodium-ion batteries. The nitrogen content of the ACN composite is as high as 20.4 %, and the bonding state of nitrogen is mostly pyridinic, as determined by X-ray photoelectron spectroscopy (XPS). The composite exhibits an excellent Na(+) storage performance with a reversible capacity of 430 mA h g(-1) and 146 mA h g(-1) at current densities of 83 mA g(-1) and 8.33 A g(-1) , respectively. A specific capacity of 175 mA h g(-1) was maintained after 2000 cycles at 1.67 A g(-1) , with only 0.016 % capacity degradation per cycle. Moreover, an accelerating rate calorimetry (ARC) test demonstrates the excellent thermal stability of the composite, with a low self heating rate and high onset temperature (210 °C). These results shows its promise as a candidate material for high-capacity, high-rate anodes for sodium-ion batteries. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanoscale Protection Layers To Mitigate Degradation in High-Energy Electrochemical Energy Storage Systems.

PubMed

Lin, Chuan-Fu; Qi, Yue; Gregorczyk, Keith; Lee, Sang Bok; Rubloff, Gary W

2018-01-16

In the pursuit of energy storage devices with higher energy and power, new ion storage materials and high-voltage battery chemistries are of paramount importance. However, they invite-and often enhance-degradation mechanisms, which are reflected in capacity loss with charge/discharge cycling and sometimes in safety problems. Degradation mechanisms are often driven by fundamentals such as chemical and electrochemical reactions at electrode-electrolyte interfaces, volume expansion and stress associated with ion insertion and extraction, and profound inhomogeneity of electrochemical behavior. While it is important to identify and understand these mechanisms at some reasonable level, it is even more critical to design strategies to mitigate these degradation pathways and to develop means to implement and validate the strategies. A growing set of research highlights the mitigation benefits achievable by forming thin protection layers (PLs) intentionally created as artificial interphase regions at the electrode-electrolyte interface. These advances illustrate a promising-perhaps even generic-pathway for enabling higher-energy and higher-voltage battery configurations. In this Account, we summarize examples of such PLs that serve as mitigation strategies to avoid degradation in lithium metal anodes, conversion-type electrode materials, and alloy-type electrodes. Examples are chosen from a larger body of electrochemical degradation research carried out in Nanostructures for Electrical Energy Storage (NEES), our DOE Energy Frontier Research Center. Overall, we argue on the basis of experimental and theoretical evidence that PLs effectively stabilize the electrochemical interfaces to prevent parasitic chemical and electrochemical reactions and mitigate the structural, mechanical, and compositional degradation of the electrode materials at the electrode-electrolyte interfaces. The evidenced improvement in performance metrics is accomplished by (1) establishing a homogeneous interface for ion insertion and extraction, (2) providing mechanical constraints to maintain structural integrity and robust electronic and ionic conduction pathways, and (3) introducing spatial confinements on the electrode material matrix to alter the phase transformation (delaying the occurrence of the conversion reaction) upon Li insertion, which results in superior electrode performance, excellent capacity retention, and improved reversibility. Taken together, these examples portray a valuable role for thin protection layers synthesized over electrode surfaces, both for their benefit to cycle stability and for revealing insights into degradation and mitigation mechanisms. Furthermore, they underscore the impact of complex electrochemical behavior at nanoscale materials and nanostructure interfaces in modulating the behavior of energy storage devices at the mesoscale and macroscale.

Multichannel Porous TiO2 Hollow Nanofibers with Rich Oxygen Vacancies and High Grain Boundary Density Enabling Superior Sodium Storage Performance.

PubMed

Wu, Ying; Jiang, Yu; Shi, Jinan; Gu, Lin; Yu, Yan

2017-06-01

TiO 2 as an anode for sodium-ion batteries (NIBs) has attracted much recent attention, but poor cyclability and rate performance remain problematic owing to the intrinsic electronic conductivity and the sluggish diffusivity of Na ions in the TiO 2 matrix. Herein, a simple process is demonstrated to improve the sodium storage performance of TiO 2 by fabricating a 1D, multichannel, porous binary-phase anatase-TiO 2 -rutile-TiO 2 composite with oxygen-deficient and high grain-boundary density (denoted as a-TiO 2- x /r-TiO 2- x ) via electrospinning and subsequent vacuum treatment. The introduction of oxygen vacancies in the TiO 2 matrix enables enhanced intrinsic electronic conductivity and fast sodium-ion diffusion kinetics. The porous structure offers easy access of the liquid electrolyte and a short transport path of Na + through the pores toward the TiO 2 nanoparticle. Furthermore, the high density of grain boundaries between the anatase TiO 2 and rutile TiO 2 offer more interfaces for a novel interfacial storage. The a-TiO 2- x /r-TiO 2- x shows excellent long cycling stability (134 mAh g -1 at 10 C after 4500 cycles) and superior rate performance (93 mAh g -1 after 4500 cycles at 20 C) for sodium-ion batteries. This simple and effective process could serve as a model for the modification of other materials applied in energy storage systems and other fields. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

STORAGE STABILITY OF PESTICIDES IN EXTRACT SOLVENTS AND SAMPLING MEDIA

EPA Science Inventory

Demonstrating that pesticides are stable in field media and their extracts over extended storage periods allows operational flexibility and cost efficiency. Stability of the 31 neutral pesticides and 2 acid herbicides of the Agricultural Health Study exposure pilot was evaluate...

Comparison of Temperature and Additives Affecting the Stability of the Probiotic Weissella cibaria

PubMed Central

Kang, Mi-Sun; Kim, Youn-Shin; Lee, Hyun-Chul; Lim, Hoi-Soon

2012-01-01

Daily use of probiotic chewing gum might have a beneficial effect on oral health, and it is important that the viability of the probiotics be maintained in this food product. In this study, we examined the stability of probiotic chewing gum containing Weissella cibaria. We evaluated the effects of various factors, including temperature and additives, on the survival of freeze-dried probiotic W. cibaria powder. No changes in viability were detected during storage at 4℃ for 5 months, whereas the viability of bacteria stored at 20℃ decreased. The stability of probiotic chewing gum decreased steadily during storage at 20℃ for 4 weeks. The viability of the freeze-dried W. cibaria mixed with various additives, such as xylitol, sorbitol, menthol, sugar ester, magnesium stearate, and vitamin C, was determined over a 4-week storage period at 20℃. Most of the freeze-dried bacteria except for those mixed with menthol and vitamin C were generally stable during a 3-week storage period. Overall, our study showed that W. cibaria was more stable at 4℃ than that at 20℃. In addition, menthol and vitamin C had a detrimental effect on the storage stability of W. cibaria. This is the first study to examine the effects of various chewing gum additives on the stability of W. cibaria. Further studies will be needed to improve the stability of probiotic bacteria for developing a novel probiotic W. cibaria gum. PMID:23323221

Facile Synthesis of V₂O₅ Hollow Spheres as Advanced Cathodes for High-Performance Lithium-Ion Batteries.

PubMed

Zhang, Xingyuan; Wang, Jian-Gan; Liu, Huanyan; Liu, Hongzhen; Wei, Bingqing

2017-01-18

Three-dimensional V₂O₅ hollow structures have been prepared through a simple synthesis strategy combining solvothermal treatment and a subsequent thermal annealing. The V₂O₅ materials are composed of microspheres 2-3 μm in diameter and with a distinct hollow interior. The as-synthesized V₂O₅ hollow microspheres, when evaluated as a cathode material for lithium-ion batteries, can deliver a specific capacity as high as 273 mAh·g -1 at 0.2 C. Benefiting from the hollow structures that afford fast electrolyte transport and volume accommodation, the V₂O₅ cathode also exhibits a superior rate capability and excellent cycling stability. The good Li-ion storage performance demonstrates the great potential of this unique V₂O₅ hollow material as a high-performance cathode for lithium-ion batteries.

Roll-to-roll production of spray coated N-doped carbon nanotube electrodes for supercapacitors

NASA Astrophysics Data System (ADS)

Karakaya, Mehmet; Zhu, Jingyi; Raghavendra, Achyut J.; Podila, Ramakrishna; Parler, Samuel G.; Kaplan, James P.; Rao, Apparao M.

2014-12-01

Although carbon nanomaterials are being increasingly used in energy storage, there has been a lack of inexpensive, continuous, and scalable synthesis methods. Here, we present a scalable roll-to-roll (R2R) spray coating process for synthesizing randomly oriented multi-walled carbon nanotubes electrodes on Al foils. The coin and jellyroll type supercapacitors comprised such electrodes yield high power densities (˜700 mW/cm3) and energy densities (1 mW h/cm3) on par with Li-ion thin film batteries. These devices exhibit excellent cycle stability with no loss in performance over more than a thousand cycles. Our cost analysis shows that the R2R spray coating process can produce supercapacitors with 10 times the energy density of conventional activated carbon devices at ˜17% lower cost.

Manganese oxides-based composite electrodes for supercapacitors

NASA Astrophysics Data System (ADS)

Su, Dongyun; Ma, Jun; Huang, Mingyu; Liu, Feng; Chen, Taizhou; Liu, Chao; Ni, Hongjun

2017-06-01

In recent, nanostructured transition metal oxides as a new class of energy storage materials have widely attracted attention due to its excellent electrochemical performance for supercapacitors. The MnO2 based transition metal oxides and their composite electrode materials were focused in the review for supercapacitor applications. The researches on different nanostructures of manganese oxides such as Nano rods, Nano sheets, nanowires, nanotubes and so on have been discovered in recent years, together with brief explanations of their properties. Research on enhancing materials’ properties by designing combination of different materials on the micron or Nano scale is too limited, and therefore we discuss the effects of different components’ sizes and their synergy on the performance. Moreover, the low-cost and large-scale fabrication of flexible supercapacitors with high performance (high energy density and cycle stability) have been pointed out and studied.

Pyrrole as a promising electrolyte additive to trap polysulfides for lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

Yang, Wu; Yang, Wang; Song, Ailing; Gao, Lijun; Sun, Gang; Shao, Guangjie

2017-04-01

Lithium-sulfur batteries are a promising energy storage devices beyond conventional lithium ion batteries. However, the "shuttle effect" of soluble polysulfides is a major barrier between electrodes, resulting in rapid capacity fading. To address above issue, pyrrole has been investigated as an electrolyte additive to trap polysulfides. When pyrrole is added into electrolyte, a surface protective layer of polypyrrole can be formed on the sulfur cathode, which not only acts as a conductive agent to provide an effective electron conduction path but also acts as an absorbing agent and barrier layer suppressing the diffusion of polysulfide intermediates. The results demonstrate that an appropriate amount of pyrrole added into the electrolyte leads to excellent cycling stability and rate capability. Apparently, pyrrole is an effective additive for the entrapment of polysulfides of lithium-sulfur batteries.

Fabrication of a stretchable solid-state micro-supercapacitor array.

PubMed

Kim, Daeil; Shin, Gunchul; Kang, Yu Jin; Kim, Woong; Ha, Jeong Sook

2013-09-24

We fabricated a stretchable micro-supercapacitor array with planar SWCNT electrodes and an ionic liquid-based triblock copolymer electrolyte. The mechanical stability of the entire supercapacitor array upon stretching was obtained by adopting strategic design concepts. First, the narrow and long serpentine metallic interconnections were encapsulated with polyimide thin film to ensure that they were within the mechanical neutral plane. Second, an array of two-dimensional planar micro-supercapacitor with SWCNT electrodes and an ion-gel-type electrolyte was made to achieve all-solid-state energy storage devices. The formed micro-supercapacitor array showed excellent performances which were stable over stretching up to 30% without any noticeable degradation. This work shows the strong potential of a stretchable micro-supercapacitor array in applications such as wearable computers, power dressing, electronic newspapers, paper-like mobile phones, and other easily collapsible gadgets.

A Highly Thermostable Ceramic-Grafted Microporous Polyethylene Separator for Safer Lithium-Ion Batteries.

PubMed

Zhu, Xiaoming; Jiang, Xiaoyu; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

2015-11-04

The safety concern is a critical obstacle to large-scale energy storage applications of lithium-ion batteries. A thermostable separator is one of the most effective means to construct the safe lithium-ion batteries. Herein, we demonstrate a novel ceramic (SiO2)-grafted PE separator prepared by electron beam irradiation. The separator shows similar thickness and pore structure to the bare separator, while displaying strong dimensional thermostability, as the shrinkage ratio is only 20% even at an elevated temperature of 180 °C. Besides, the separator is highly electrochemically inert, showing no adverse effect on the energy and power output of the batteries. Considering the excellent electrochemical and thermal stability, the SiO2-grafted PE separator developed in this work is greatly beneficial for constructing safer lithium-ion batteries.

Composite lithium metal anode by melt infusion of lithium into a 3D conducting scaffold with lithiophilic coating.

PubMed

Liang, Zheng; Lin, Dingchang; Zhao, Jie; Lu, Zhenda; Liu, Yayuan; Liu, Chong; Lu, Yingying; Wang, Haotian; Yan, Kai; Tao, Xinyong; Cui, Yi

2016-03-15

Lithium metal-based battery is considered one of the best energy storage systems due to its high theoretical capacity and lowest anode potential of all. However, dendritic growth and virtually relative infinity volume change during long-term cycling often lead to severe safety hazards and catastrophic failure. Here, a stable lithium-scaffold composite electrode is developed by lithium melt infusion into a 3D porous carbon matrix with "lithiophilic" coating. Lithium is uniformly entrapped on the matrix surface and in the 3D structure. The resulting composite electrode possesses a high conductive surface area and excellent structural stability upon galvanostatic cycling. We showed stable cycling of this composite electrode with small Li plating/stripping overpotential (<90 mV) at a high current density of 3 mA/cm(2) over 80 cycles.

Depolarization current relaxation process of insulating dielectrics after corona poling under different charging conditions

NASA Astrophysics Data System (ADS)

Zhang, J. W.; Zhou, T. C.; Wang, J. X.; Yang, X. F.; Zhu, F.; Tian, L. M.; Liu, R. T.

2017-10-01

As an insulating dielectric, polyimide is favorable for the application of optoelectronics, electrical insulation system in electric power industry, insulating, and packaging materials in space aircraft, due to its excellent thermal, mechanical and electrical insulating stability. The charge storage profile of such insulating dielectric is utmost important to its application, when it is exposed to electron irradiation, high voltage corona discharge or other treatments. These treatments could induce changes in physical and chemical properties of treated samples. To investigate the charge storage mechanism of the insulating dielectrics after high-voltage corona discharge, the relaxation processes responsible for corona charged polyimide films under different poling conditions were analyzed by the Thermally Stimulated Discharge Currents method (TSDC). In the results of thermal relaxation process, the appearance of various peaks in TSDC spectra provided a deep insight into the molecular status in the dielectric material and reflected stored space charge relaxation process in the insulating polymers after corona discharge treatments. Furthermore, the different space charge distribution status under various poling temperature and different discharge voltage level were also investigated, which could partly reflect the influence of the ambiance condition on the functional dielectrics after corona poling.

Quasi-Solid-State Rechargeable Li-O2 Batteries with High Safety and Long Cycle Life at Room Temperature.

PubMed

Cho, Sung Man; Shim, Jimin; Cho, Sung Ho; Kim, Jiwoong; Son, Byung Dae; Lee, Jong-Chan; Yoon, Woo Young

2018-05-09

As interest in electric vehicles and mass energy storage systems continues to grow, Li-O 2 batteries are attracting much attention as a candidate for next-generation energy storage systems owing to their high energy density. However, safety problems related to the use of lithium metal anodes have hampered the commercialization of Li-O 2 batteries. Herein, we introduced a quasi-solid polymer electrolyte with excellent electrochemical, chemical, and thermal stabilities into Li-O 2 batteries. The ion-conducting QSPE was prepared by gelling a polymer network matrix consisting of poly(ethylene glycol) methyl ether methacrylate, methacrylated tannic acid, lithium trifluoromethanesulfonate, and nanofumed silica with a small amount of liquid electrolyte. The quasi-solid-state Li-O 2 cell consisted of a lithium powder anode, a quasi-solid polymer electrolyte, and a Pd 3 Co/multiwalled carbon nanotube cathode, which enhanced the electrochemical performance of the cell. This cell, which exhibited improved safety owing to the suppression of lithium dendrite growth, achieved a lifetime of 125 cycles at room temperature. These results show that the introduction of a quasi-solid electrolyte is a potentially new alternative for the commercialization of solid-state Li-O 2 batteries.

Facile Synthesis of a Pentiptycene-Based Highly Microporous Organic Polymer for Gas Storage and Water Treatment.

PubMed

Luo, Shuangjiang; Zhang, Qinnan; Zhang, Yizhou; Weaver, Kevin P; Phillip, William A; Guo, Ruilan

2018-05-02

Rigid H-shaped pentiptycene units, with an intrinsic hierarchical structure, were employed to fabricate a highly microporous organic polymer sorbent via Friedel-Crafts reaction/polymerization. The obtained microporous polymer exhibits good thermal stability, a high Brunauer-Emmett-Teller surface area of 1604 m 2 g -1 , outstanding CO 2 , H 2 , and CH 4 storage capacities, as well as good adsorption selectivities for the separation of CO 2 /N 2 and CO 2 /CH 4 gas pairs. The CO 2 uptake values reached as high as 5.00 mmol g -1 (1.0 bar and 273 K), which, along with high adsorption selectivity values (e.g., 47.1 for CO 2 /N 2 ), make the pentiptycene-based microporous organic polymer (PMOP) a promising sorbent material for carbon capture from flue gas and natural gas purification. Moreover, the PMOP material displayed superior absorption capacities for organic solvents and dyes. For example, the maximum adsorption capacities for methylene blue and Congo red were 394 and 932 mg g -1 , respectively, promoting the potential of the PMOP as an excellent sorbent for environmental remediation and water treatment.

Two-Dimensional Porous Sandwich-Like C/Si-Graphene-Si/C Nanosheets for Superior Lithium Storage.

PubMed

Yao, Weiqi; Chen, Jie; Zhan, Liang; Wang, Yanli; Yang, Shubin

2017-11-15

A novel two-dimensional porous sandwich-like Si/carbon nanosheet is designed and successfully fabricated as an anode for superior lithium storage, where a porous Si nanofilm grows on the two sides of reduced graphene oxide (rGO) and is then coated with a carbon layer (denoted as C/Si-rGO-Si/C). The coexistence of micropores and mesopores in C/Si-rGO-Si/C nanosheets offers a rapid Li + diffusion rate, and the porous Si provides a short pathway for electric transportation. Meanwhile, the coated carbon layer not only can promote to form a stable SEI layer, but also can improve the electric conductivity of nanoscale Si coupled with rGO. Thus, the unique nanostructures offer the resultant C/Si-rGO-Si/C electrode with high reversible capacity (1187 mA h g -1 after 200 cycles at 0.2 A g -1 ), excellent cycle stability (894 mA h g -1 after 1000 cycles at 1 A g -1 ), and high rate capability (694 mA h g -1 at 5 A g -1 , 447 mA h g -1 at 10 A g -1 ).

Flexible Transparent Supercapacitors Based on Hierarchical Nanocomposite Films.

PubMed

Chen, Fanhong; Wan, Pengbo; Xu, Haijun; Sun, Xiaoming

2017-05-31

Flexible transparent electronic devices have recently gained immense popularity in smart wearable electronics and touch screen devices, which accelerates the development of the portable power sources with reliable flexibility, robust transparency and integration to couple these electronic devices. For potentially coupled as energy storage modules in various flexible, transparent and portable electronics, the flexible transparent supercapacitors are developed and assembled from hierarchical nanocomposite films of reduced graphene oxide (rGO) and aligned polyaniline (PANI) nanoarrays upon their synergistic advantages. The nanocomposite films are fabricated from in situ PANI nanoarrays preparation in a blended solution of aniline monomers and rGO onto the flexible, transparent, and stably conducting film (FTCF) substrate, which is obtained by coating silver nanowires (Ag NWs) layer with Meyer rod and then coating of rGO layer on polyethylene terephthalate (PET) substrate. Optimization of the transparency, the specific capacitance, and the flexibility resulted in the obtained all-solid state nanocomposite supercapacitors exhibiting enhanced capacitance performance, good cycling stability, excellent flexibility, and superior transparency. It provides promising application prospects for exploiting flexible, low-cost, transparent, and high-performance energy storage devices to be coupled into various flexible, transparent, and wearable electronic devices.

High-quality metal oxide core/shell nanowire arrays on conductive substrates for electrochemical energy storage.

PubMed

Xia, Xinhui; Tu, Jiangping; Zhang, Yongqi; Wang, Xiuli; Gu, Changdong; Zhao, Xin-Bing; Fan, Hong Jin

2012-06-26

The high performance of a pseudocapacitor electrode relies largely on a scrupulous design of nanoarchitectures and smart hybridization of bespoke active materials. We present a powerful two-step solution-based method for the fabrication of transition metal oxide core/shell nanostructure arrays on various conductive substrates. Demonstrated examples include Co(3)O(4) or ZnO nanowire core and NiO nanoflake shells with a hierarchical and porous morphology. The "oriented attachment" and "self-assembly" crystal growth mechanisms are proposed to explain the formation of the NiO nanoflake shell. Supercapacitor electrodes based on the Co(3)O(4)/NiO nanowire arrays on 3D macroporous nickel foam are thoroughly characterized. The electrodes exhibit a high specific capacitance of 853 F/g at 2 A/g after 6000 cycles and an excellent cycling stability, owing to the unique porous core/shell nanowire array architecture, and a rational combination of two electrochemically active materials. Our growth approach offers a new technique for the design and synthesis of transition metal oxide or hydroxide hierarchical nanoarrays that are promising for electrochemical energy storage, catalysis, and gas sensing applications.

Design and fabrication of highly open nickel cobalt sulfide nanosheets on Ni foam for asymmetric supercapacitors with high energy density and long cycle-life

NASA Astrophysics Data System (ADS)

Zha, Daosong; Fu, Yongsheng; Zhang, Lili; Zhu, Junwu; Wang, Xin

2018-02-01

Nickel cobalt sulfides (NiCo-S) are promising electrode materials for high-performance supercapacitors but normally show poor rate capability and unsatisfactory long-term endurance. To overcome these disadvantages, a properly constructed electrode architecture with abundant electron transport channels, excellent electronic conductivity and robust structural stability is required. Herein, considering that in situ transformation can mostly retain the specific structural advantages of the precursors, a two-step strategy is purposefully developed to construct a binder-free electrode composed of interconnected NiCo-S nanosheets on Ni foam (NiCo-S/NF), in which NiCo-S/NF is synthesized via the in situ sulfuration of networked acetate anion-intercalated nickel cobalt layered double hydroxide nanosheets loaded on Ni foam (A-NiCo-LDH/NF). Noticeably, the optimized Ni1Co1-S/NF exhibits an ultrahigh specific capacitance of 2553.9 F g-1 at 0.5 A g-1, excellent rate capability (1898.1 F g-1 at 50 A g-1) and superior cycling stability (nearly 90% capacitance retention after 10,000 cycles). Furthermore, the assembled asymmetric supercapacitor based on Ni1Co1-S/NF demonstrates a high energy density of 58.1 Wh kg-1 at a power density of 796 W kg-1 and impressive long-term durability even after a repeated charge/discharge process as long as 70,000 cycles (∼92% capacitance retention). The attractive properties endow the Ni1Co1-S/NF electrode with significant potential for high-performance energy storage devices.

Delayed release film coating applications on oral solid dosage forms of proton pump inhibitors: case studies.

PubMed

Missaghi, Shahrzad; Young, Cara; Fegely, Kurt; Rajabi-Siahboomi, Ali R

2010-02-01

Formulation of proton pump inhibitors (PPIs) into oral solid dosage forms is challenging because the drug molecules are acid-labile. The aim of this study is to evaluate different formulation strategies (monolithic and multiparticulates) for three PPI drugs, that is, rabeprazole sodium, lansoprazole, and esomeprazole magnesium, using delayed release film coating applications. The core tablets of rabeprazole sodium were prepared using organic wet granulation method. Multiparticulates of lansoprazole and esomeprazole magnesium were prepared through drug layering of sugar spheres, using powder layering and suspension layering methods, respectively. Tablets and drug-layered multiparticulates were seal-coated, followed by delayed release film coating application, using Acryl-EZE(R), aqueous acrylic enteric system. Multiparticulates were then filled into capsules. The final dosage forms were evaluated for physical properties, as well as in vitro dissolution testing in both compendial acid phase, 0.1N HCl (pH 1.2), and intermediate pH, acetate buffer (pH 4.5), followed by phosphate buffer, pH 6.8. The stability of the delayed release dosage forms was evaluated upon storage in accelerated conditions [40 degrees C/75% relative humidity] for 3 months. All dosage forms demonstrated excellent enteric protection in the acid phase, followed by rapid release in their respective buffer media. Moreover, the delayed release dosage forms remained stable under accelerated stability conditions for 3 months. Results showed that Acryl-EZE enteric coating systems provide excellent performance in both media (0.1N HCl and acetate buffer pH 4.5) for monolithic and multiparticulate dosage forms.

From Physics to industry: EOS outside HEP

NASA Astrophysics Data System (ADS)

Espinal, X.; Lamanna, M.

2017-10-01

In the competitive market for large-scale storage solutions the current main disk storage system at CERN EOS has been showing its excellence in the multi-Petabyte high-concurrency regime. It has also shown a disruptive potential in powering the service in providing sync and share capabilities and in supporting innovative analysis environments along the storage of LHC data. EOS has also generated interest as generic storage solution ranging from university systems to very large installations for non-HEP applications.

Thermal and storage characteristics of tomato seed oil

USDA-ARS?s Scientific Manuscript database

Thermal oxidative stability and effect of different storage conditions on quality characteristics of tomato seed oil have not been studied. The objectives of this research were to determine the changes in quality and oxidative stability of tomato seed oil, including color, antioxidant activity, per...

Nitrogen source affects productivity, desiccation tolerance, and storage stability of Beauveria bassiana blastospores

USDA-ARS?s Scientific Manuscript database

Aims: Nitrogen is a critical element in industrial fermentation media. This study investigated the influence of various nitrogen sources on blastospore production, tolerance to anhydrobiosis stress, and storage stability using two strains of the cosmopolitan insect pathogenic fungus Beauveria bassia...

Applicability of canisters for sample storage in the determination of hazardous air pollutants

NASA Astrophysics Data System (ADS)

Kelly, Thomas J.; Holdren, Michael W.

This paper evaluates the applicability of canisters for storage of air samples containing volatile organic compounds listed among the 189 hazardous air pollutants (HAPs) in the 1990 U.S. Clean Air Act Amendments. Nearly 100 HAPs have sufficient vapor pressure to be considered volatile compounds. Of those volatile organic HAPs, 52 have been tested previously for stability during storage in canisters. The published HAP stability studies are reviewed, illustrating that for most of the 52 HAPs tested, canisters are an effective sample storage approach. However, the published stability studies used a variety of canister types and test procedures, and generally considered only a few compounds in a very small set of canisters. A comparison of chemical and physical properties of the HAPs has also been conducted, to evaluate the applicability of canister sampling for other HAPs, for which canister stability testing has never been conducted. Of 45 volatile HAPs never tested in canisters, this comparison identifies nine for which canisters should be effective, and 17 for which canisters are not likely to be effective. For the other 19 HAPs, no clear decision can be reached on the likely applicability of air sample storage in canisters.

Robust biomimetic-structural superhydrophobic surface on aluminum alloy.

PubMed

Li, Lingjie; Huang, Tao; Lei, Jinglei; He, Jianxin; Qu, Linfeng; Huang, Peiling; Zhou, Wei; Li, Nianbing; Pan, Fusheng

2015-01-28

The following facile approach has been developed to prepare a biomimetic-structural superhydrophobic surface with high stabilities and strong resistances on 2024 Al alloy that are robust to harsh environments. First, a simple hydrothermal treatment in a La(NO3)3 aqueous solution was used to fabricate ginkgo-leaf like nanostructures, resulting in a superhydrophilic surface on 2024 Al. Then a low-surface-energy compound, dodecafluoroheptyl-propyl-trimethoxylsilane (Actyflon-G502), was used to modify the superhydrophilic 2024 Al, changing the surface character from superhydrophilicity to superhydrophobicity. The water contact angle (WCA) of such a superhydrophobic surface reaches up to 160°, demonstrating excellent superhydrophobicity. Moreover, the as-prepared superhydrophobic surface shows high stabilities in air-storage, chemical and thermal environments, and has strong resistances to UV irradiation, corrosion, and abrasion. The WCAs of such a surface almost remain unchanged (160°) after storage in air for 80 days, exposure in 250 °C atmosphere for 24 h, and being exposed under UV irradiation for 24 h, are more than 144° whether in acidic or alkali medium, and are more than 150° after 48 h corrosion and after abrasion under 0.98 kPa for 1000 mm length. The remarkable durability of the as-prepared superhydrophobic surface can be attributed to its stable structure and composition, which are due to the existence of lanthanum (hydr)oxides in surface layer. The robustness of the as-prepared superhydrophobic surface to harsh environments will open their much wider applications. The fabricating approach for such robust superhydrophobic surface can be easily extended to other metals and alloys.

Physicochemical stability and biological activity of Withania somnifera extract under real-time and accelerated storage conditions.

PubMed

Patil, Dada; Gautam, Manish; Jadhav, Umesh; Mishra, Sanjay; Karupothula, Suresh; Gairola, Sunil; Jadhav, Suresh; Patwardhan, Bhushan

2010-03-01

Stability testing at preformulation stages is a crucial part of drug development. We studied physicochemical stability and biological activity of Withania somnifera (ashwagandha) dried root aqueous extract during six months real-time and under accelerated storage conditions. The characteristic constituents of ashwagandha roots include withanolides such as withaferin A and withanolide A. We modified and validated the HPLC-DAD method for quantitative measurement of withanolides and fingerprint analysis. The results suggest a significant decline in withaferin A and withanolide A content under real and accelerated conditions. The HPLC fingerprint analysis showed significant changes in some peaks during real and accelerated storage (> 20 %). We also observed incidences of clump formation and moisture sensitivity (> 10 %) under real-time and accelerated storage conditions. These changes were concurrent with a significant decline in immunomodulatory activity (p < 0.01) during the third month of the accelerated storage. Thus, adequate control of temperature and humidity is important for WSE containing formulations. This study may help in proposing suitable guidance for storage conditions and shelf life of ashwagandha formulations. (c) Georg Thieme Verlag KG Stuttgart . New York.

The Or gene enhances carotenoid accumulation and stability during post-harvest storage of potato tubers

USDA-ARS?s Scientific Manuscript database

Provitamin A carotenoids in staple crops are not very stable during storage and their loss compromises nutritional quality. To elucidate the fundamental mechanisms underlying carotenoid accumulation and stability, we investigated transgenic potato tubers that express the cauliflower Orange (Or) gene...

Proceedings of the 6. international conference on stability and handling of liquid fuels. Volume 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giles, H.N.

1998-12-01

Volume 1 of these proceedings contain 29 papers related to aviation fuels and long term and strategic storage. Studies investigated fuel contamination, separation processes, measurement techniques, thermal stability, compatibility with fuel system materials, oxidation reactions, and degradation during storage.

The origin of excellent gate-bias stress stability in organic field-effect transistors employing fluorinated-polymer gate dielectrics.

PubMed

Kim, Jiye; Jang, Jaeyoung; Kim, Kyunghun; Kim, Haekyoung; Kim, Se Hyun; Park, Chan Eon

2014-11-12

Tuning of the energetic barriers to charge transfer at the semiconductor/dielectric interface in organic field-effect transistors (OFETs) is achieved by varying the dielectric functionality. Based on this, the correlation between the magnitude of the energy barrier and the gate-bias stress stability of the OFETs is demonstrated, and the origin of the excellent device stability of OFETs employing fluorinated dielectrics is revealed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impact of Oral Fluid Collection Device on Cannabinoid Stability Following Smoked Cannabis

PubMed Central

Anizan, Sébastien; Bergamaschi, Mateus M.; Barnes, Allan J.; Milman, Garry; Desrosiers, Nathalie; Lee, Dayong; Gorelick, David A.; Huestis, Marilyn A.

2014-01-01

Evaluation of cannabinoid stability in authentic oral fluid (OF) is critical, as most OF stability studies employed fortified or synthetic OF. Participants (n=16) smoked a 6.8% delta-9-tetrahydrocannabinol (THC) cigarette, and baseline concentrations of THC, 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), and cannabinol (CBN) were determined within 24h in 16 separate pooled samples (collected 1h before to 10.5 or 13h after smoking). OF was collected with the StatSure Saliva Sampler™ and Oral-Eze® devices. Oral-Eze samples were re-analyzed after room temperature (RT) storage for 1 week, and for both devices after 4°C for 1 and 4 weeks, and –20°C for 4 and 24 weeks. Concentrations ±20% from initial concentrations were considered stable. With the StatSure device, all cannabinoids were within 80-120% median %baseline for all storage conditions. Individual THC, CBD, CBN and THCCOOH pool concentrations were stable in 100%, 100%, 80-94% and >85%, respectively, across storage conditions. With the Oral-Eze device, at RT or refrigerated storage (for 1 and 4 weeks), THC, CBD and THCCOOH were stable in 94-100%, 78-89% and 93-100% of samples, respectively, while CBN concentrations were 53–79% stable. However, after 24 weeks at -20°C, stability decreased, especially for CBD, with a median of 56% stability. Overall, the collection devices’ elution/stabilizing buffers provided good stability for OF cannabinoids, with the exception of the more labile CBN. To ensure OF cannabinoid concentration accuracy, these data suggest analysis within 4 weeks at 4°C storage for Oral-Eze collection and within 4 weeks at 4°C or 24 weeks at -20°C for StatSure collection. PMID:24995604

Long-term sera storage does not significantly modify the interpretation of toxoplasmosis serologies.

PubMed

Dard, C; Bailly, S; Drouet, T; Fricker-Hidalgo, H; Brenier-Pinchart, M P; Pelloux, H

2017-03-01

Serological investigation of Toxoplasma gondii can answer many questions about toxoplasmosis in human pathology. Along these lines, studies on serum storage in biobanks need to be performed especially in terms of determining the impact of storage on relevance of sera analysis after freezing. This study assessed the impact of long-term sera storage on the stability of anti-Toxoplasma immunoglobulins. The stability of anti-Toxoplasma IgG and IgM was studied in 244 and 242 sera respectively, stored at -20°C from one month to ten years. ELISA-immunoassay (Vidas®, bioMérieux) was used for initial and post-storage analyses. Linear models for repeated measures and subgroup analyses were performed to assess the effect of storage duration and sample characteristics on immunoglobulins stability. Until ten years, the variability attributed to storage (maximum 8.07% for IgG, 13.17% for IgM) was below the variations inherent to the serological technique and allowed by quality assurance systems (15%). Subgroup analysis reported no variation attributed to sera storage. Serological interpretation was modified for 3 sera (1.2%) tested for IgM, all stored more than seven years. Anti-Toxoplasma immunoglobulins can reliably be measured for at least up to six years of storage with no modification of interpretation of toxoplasmosis serologies. Copyright © 2017 Elsevier B.V. All rights reserved.

29 CFR 1926.857 - Storage.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 8 2012-07-01 2012-07-01 false Storage. 1926.857 Section 1926.857 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Demolition § 1926.857 Storage. (a) The storage of waste... provide storage space for debris, provided falling material is not permitted to endanger the stability of...

29 CFR 1926.857 - Storage.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 8 2011-07-01 2011-07-01 false Storage. 1926.857 Section 1926.857 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Demolition § 1926.857 Storage. (a) The storage of waste... provide storage space for debris, provided falling material is not permitted to endanger the stability of...

29 CFR 1926.857 - Storage.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 8 2014-07-01 2014-07-01 false Storage. 1926.857 Section 1926.857 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Demolition § 1926.857 Storage. (a) The storage of waste... provide storage space for debris, provided falling material is not permitted to endanger the stability of...

29 CFR 1926.857 - Storage.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 8 2013-07-01 2013-07-01 false Storage. 1926.857 Section 1926.857 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Demolition § 1926.857 Storage. (a) The storage of waste... provide storage space for debris, provided falling material is not permitted to endanger the stability of...

29 CFR 1926.857 - Storage.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 8 2010-07-01 2010-07-01 false Storage. 1926.857 Section 1926.857 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Demolition § 1926.857 Storage. (a) The storage of waste... provide storage space for debris, provided falling material is not permitted to endanger the stability of...

Influence of Temperature and Humidity on the Stability of Carotenoids in Biofortified Maize (Zea mays L.) Genotypes during Controlled Postharvest Storage.

PubMed

Ortiz, Darwin; Rocheford, Torbert; Ferruzzi, Mario G

2016-04-06

Maize is a staple crop that has been the subject of biofortification efforts to increase the natural content of provitamin A carotenoids. Although significant progress toward increasing provitamin A carotenoid content in maize varieties has been made, postharvest handling factors that influence carotenoid stability during storage have not been fully established. The objectives of this study were to determine carotenoid profiles of six selected provitamin A biofortified maize genotypes at various developmental stages and assess the stability of carotenoids in maize kernels during controlled storage conditions (12 month period), including elevated temperature and relative humidity. There were no significant changes in the content of individual carotenoids within genotypes during kernel development from 45 days after pollination through the time of harvest. Carotenoid losses through traditional grain drying were also minimal (<9%). However, the stability of carotenoids in maize kernels over storage time after harvest was found to be dependent on both temperature and humidity, with variation observed among genotypes. Different forms of provitamin A carotenoids follow similar degradation rates. The genotype C17xDE3 had a degradation rate 2 times faster than those of the other genotypes evaluated (P < 0.001). These differences in carotenoid stability under controlled storage were attributed, in part, to observed differences in the physical properties of the kernels (surface area and porosity). These results support the notion that effective control of moisture content and temperature of the kernels during storage conditions is essential to reduce the speed of degradative reactions.

Hydrogen storage of Mg1-xMxH2 (M = Ti, V, Fe) studied using first-principles calculations

NASA Astrophysics Data System (ADS)

Bhihi, M.; Lakhal, M.; Labrim, H.; Benyoussef, A.; A. El, Kenz; Mounkachi, O.; K. Hlil, E.

2012-09-01

In this work, the hydrogen storage properties of the Mg-based hydrides, i.e., Mg1-x Mx H2 (M = Ti, V, Fe, 0 <= x <= 0.1), are studied using the Korringa—Kohn—Rostoker (KKR) calculation with the coherent potential approximation (CPA). In particular, the nature and concentrations of the alloying elements and their effects are studied. Moreover, the material's stability and hydrogen storage thermodynamic properties are discussed. In particular, we find that the stability and the temperature of desorption decrease without significantly affecting the storage capacities.

Storage Stability of Food Protein Hydrolysates-A Review.

PubMed

Rao, Qinchun; Klaassen Kamdar, Andre; Labuza, Theodore P

2016-05-18

In recent years, mainly due to the specific health benefits associated with (1) the discovery of bioactive peptides in protein hydrolysates, (2) the reduction of protein allergenicity by protein hydrolysis, and (3) the improved protein digestibility and absorption of protein hydrolysates, the utilization of protein hydrolysates in functional foods and beverages has significantly increased. Although the specific health benefits from different hydrolysates are somewhat proven, the delivery and/or stability of these benefits is debatable during distribution, storage, and consumption. In this review, we discuss (1) the quality changes in different food protein hydrolysates during storage; (2) the resulting changes in the structure and texture of three food matrices, i.e., low moisture foods (LMF, aw < 0.6), intermediate moisture foods (IMF, 0.6 ≤ aw < 0.85), and high moisture foods (HMF, aw ≥ 0.85); and (3) the potential solutions to improve storage stability of food protein hydrolysates. In addition, we note there is a great need for evaluation of biofunction availability of bioactive peptides in food protein hydrolysates during storage.

Improvement in storage stability of infrared dried rough rice

USDA-ARS?s Scientific Manuscript database

The objective of this study was to develop infrared drying (IRD) method to improve the stability of physicochemical properties of rough rice during storage. The effect of IRD on the physicochemical properties of stored rough rice was compared with that of hot air drying (HAD) and ambient air drying ...

Long-term physical and oxidative stability of liposomes containing glycerides of lipoic acid

USDA-ARS?s Scientific Manuscript database

The acyl glycerides of lipoic and dihydrolipoic acids may serve as slow-release sources for cutaneous delivery of these antioxidants when formulated in a liposomal vehicle. Accelerated storage testing was conducted to determine the storage stability of the lipoic derivatives and of the soybean phosp...

Highly Nitrogen-Doped Three-Dimensional Carbon Fibers Network with Superior Sodium Storage Capacity.

PubMed

Lei, Wen; Xiao, Weiping; Li, Jingde; Li, Gaoran; Wu, Zexing; Xuan, Cuijuan; Luo, Dan; Deng, Ya-Ping; Wang, Deli; Chen, Zhongwei

2017-08-30

Inspired by the excellent absorption capability of spongelike bacterial cellulose (BC), three-dimensional hierarchical porous carbon fibers doped with an ultrahigh content of N (21.2 atom %) (i.e., nitrogen-doped carbon fibers, NDCFs) were synthesized by an adsorption-swelling strategy using BC as the carbonaceous material. When used as anode materials for sodium-ion batteries, the NDCFs deliver a high reversible capacity of 86.2 mAh g -1 even after 2000 cycles at a high current density of 10.0 A g -1 . It is proposed that the excellent Na + storage performance is mainly due to the defective surface of the NDCFs created by the high content of N dopant. Density functional theory (DFT) calculations show that the defect sites created by N doping can strongly "host" Na + and therefore contribute to the enhanced storage capacity.

Development of Special Biological Products

DTIC Science & Technology

1981-01-01

Rocky Mountain Spotted Fever (RMSF) 20. Continued B. Tissue Culture / ?Two production lots of FRhL-2 dnd three of MRC-5 were stabilized...104) was potency tested. J. Q Fever Vaccine Storage Stability Potency Testing Q fever vaccine (NDBR 105) was put on potency test. K. Rocky Mountain Spotted Fever (RMSF...Fever Vaccine Storage Stability Potency Testing Two lots of Q fever vaccine (NDBR 105) were put on potency test. K. Rocky Mountain Spotted Fever

Biomass-derived sponge-like carbonaceous hydrogels and aerogels for supercapacitors.

PubMed

Wu, Xi-Lin; Wen, Tao; Guo, Hong-Li; Yang, Shubin; Wang, Xiangke; Xu, An-Wu

2013-04-23

As a newly developed material, carbon gels have been receiving considerable attention due to their multifunctional properties. Herein, we present a facile, green, and template-free route toward sponge-like carbonaceous hydrogels and aerogels by using crude biomass, watermelon as the carbon source. The obtained three-dimensional (3D) flexible carbonaceous gels are made of both carbonaceous nanofibers and nanospheres. The porous carbonaceous gels (CGs) are highly chemically active and show excellent mechanical flexibility which enable them to be a good scaffold for the synthesis of 3D composite materials. We synthesized the carbonaceous gel-based composite materials by incorporating Fe3O4 nanoparticles into the networks of the carbonaceous gels. The Fe3O4/CGs composites further transform into magnetite carbon aerogels (MCAs) by calcination. The MCAs keep the porous structure of the original CGs, which allows the sustained and stable transport of both electrolyte ions and electrons to the electrode surface, leading to excellent electrochemical performance. The MCAs exhibit an excellent capacitance of 333.1 F·g(-1) at a current density of 1 A·g(-1) within a potential window of -1.0 to 0 V in 6 M KOH solution. Meanwhile, the MCAs also show outstanding cycling stability with 96% of the capacitance retention after 1000 cycles of charge/discharge. These findings open up the use of low-cost elastic carbon gels for the synthesis of other 3D composite materials and show the possibility for the application in energy storage.

Prepared multifunctional aerogel for high performance supercapacitors and effective adsorbents

NASA Astrophysics Data System (ADS)

Zhang, Yimei; Wang, Fei; Ou, Ping; Zhu, Hao; Zhao, Yalong; Wang, Liquan; Chen, Zhuang; Li, Shuai

2018-05-01

Energy and environment as the current research hots pot, how to effectively combine the two is very important and full of challenge. In this research, we design a new type multifunctional aerogel material, which not only can applied for supuercapacitors, but also acted as adsorbents for adsorb organic pollutant. This multifunctional aerogel was prepared by one-pot hydrothermal and freeze-drying method based on elongated TiO2 nanotubes (eTNTs) and graphene. During the hydrothermal process, the graphene nanosheets and eTNTs self-assembled into three-dimensional (3D) interconnected networks, in which the eTNTs with uniform size are intercalate the pore interconnected framework. The results show that the as-prepared eTNTs/graphene aerogel (TGA) exhibits a high specific surface area of 343.2 m2 g‑1. The highly porous and interconnected 3D nanostructure provided efficient migration of electrolyte ions and electrons, and thus the TGA exhibited excellent electrochemical performance for supercapacitors. The binder free TGA electrode possessed high performance electrochemical properties with an excellent specific capacitance (476.8 F g‑1 at scan rate of 5 mV s‑1), and outstanding cycle stability (92% capacitance retention after 5000 cycles). In addition, the TGA also showed admirable adsorption capacity for organic pollutant of bisphenol A, which reached 523.5 mg g‑1. The excellent electrochemical and adsorption capacities suggest the TGA to be the promising materials application in energy storage and environmental remediation.

Kelp-derived three-dimensional hierarchical porous N, O-doped carbon for flexible solid-state symmetrical supercapacitors with excellent performance

NASA Astrophysics Data System (ADS)

Zhang, Yifu; Jiang, Hanmei; Wang, Qiushi; Zheng, Jiqi; Meng, Changgong

2018-07-01

Three-dimensional (3D) porous N, O-doped carbon with hierarchical structures composed of micropores, mesopores and macropores were synthesized by the direct carbonization of kelp with a "self-activation" process. The as-obtained 3D N, O-doped carbon remained abundant N and O functional groups and the BET specific surface area measured 656 m2 g-1. 3D hierarchical porous structures with the pore size ranged from several nanometers to hundred nanometers and lots of pores were attributed to mesopores with the average pore size of about 5.4 nm. Electrochemical properties of the 3D hierarchical porous N, O-doped carbon as a supercapactior (SC) electrode were investigated and it delivered excellent capacitance of 669 mF cm-2 at 1 mA cm-2 due to its 3D hierarchical porous structures with high specific surface area which is beneficial for improving ionic storage and transportation in electrodes. This kelp-derived carbon exhibited excellent cyclic performance with the retention of 104% after 10,000 cycles. A flexible solid-state symmetric SC (SSC) device was fabricated using the 3D hierarchical porous N, O-doped carbon and delivered an excellent capacitance of 412 mF cm-2 at 2 mA cm-2 and satisfying cyclic stability with the retention of 85% after 10,000 cycles. The areal energy density of the SSC device reach up to 0.146 mWh cm-2 at the power density of 0.8 mW cm-2. This facile route for low-cost carbonaceous materials with novel architecture and functionality can be as a promising alternative to synthesize biomass carbon for practical SC application.

Mesoporous carbon-coated LiFePO4 nanocrystals co-modified with graphene and Mg2+ doping as superior cathode materials for lithium ion batteries.

PubMed

Wang, Bo; Xu, Binghui; Liu, Tiefeng; Liu, Peng; Guo, Chenfeng; Wang, Shuo; Wang, Qiuming; Xiong, Zhigang; Wang, Dianlong; Zhao, X S

2014-01-21

In this work, mesoporous carbon-coated LiFePO4 nanocrystals further co-modified with graphene and Mg(2+) doping (G/LFMP) were synthesized by a modified rheological phase method to improve the speed of lithium storage as well as cycling stability. The mesoporous structure of LiFePO4 nanocrystals was designed and realized by introducing the bead milling technique, which assisted in forming sucrose-pyrolytic carbon nanoparticles as the template for generating mesopores. For comparison purposes, samples modified only with graphene (G/LFP) or Mg(2+) doping (LFMP) as well as pure LiFePO4 (LFP) were also prepared and investigated. Microscopic observation and nitrogen sorption analysis have revealed the mesoporous morphologies of the as-prepared composites. X-ray diffraction (XRD) and Rietveld refinement data demonstrated that the Mg-doped LiFePO4 is a single olivine-type phase and well crystallized with shortened Fe-O and P-O bonds and a lengthened Li-O bond, resulting in an enhanced Li(+) diffusion velocity. Electrochemical properties have also been investigated after assembling coin cells with the as-prepared composites as the cathode active materials. Remarkably, the G/LFMP composite has exhibited the best electrochemical properties, including fast lithium storage performance and excellent cycle stability. That is because the modification of graphene provided active sites for nuclei, restricted the in situ crystallite growth, increased the electronic conductivity and reduced the interface reaction current density, while, Mg(2+) doping improved the intrinsically electronic and ionic transfer properties of LFP crystals. Moreover, in the G/LFMP composite, the graphene component plays the role of "cushion" as it could quickly realize capacity response, buffering the impact to LFMP under the conditions of high-rate charging or discharging, which results in a pre-eminent rate capability and cycling stability.

Challenges Encountered Using Ophthalmic Anesthetics in Space Medicine

NASA Technical Reports Server (NTRS)

Bayuse, T.; Law, J.; Alexander, D.; Moynihan, S.; LeBlanc, C.; Langford, K.; Magalhaes, L.

2015-01-01

On orbit, ophthalmic anesthetics are used for tonometry and off-nominal corneal examinations. Proparacaine has been flown traditionally. However, the manufacturers recently changed its storage requirements from room temperature storage to refrigerated storage to preserve stability and prolong the shelf-life. Since refrigeration on orbit is not readily available and there were stability concerns about flying proparacaine unrefrigerated, tetracaine was selected as an alternative ophthalmic anesthetic in 2013. We will discuss the challenges encountered flying and using these anesthetics on the International Space Station.

Mechanisms of deterioration of nutrients. [of freeze dried foods

NASA Technical Reports Server (NTRS)

Karel, M.; Flink, J. M.

1976-01-01

Methods which produce freeze dried foods of improved quality were examined with emphasis on storage stability. Specific topics discussed include: microstructure of freeze dried systems, investigation of structural changes in freeze dried systems, artificial food matrices, osmotic preconcentration to yield improved quality freeze dried fruits, and storage stability of osmotically preconcentrated freeze dried fruits.

Impact of pilling and long-term topsoil storage on the potential soil microbial activity in the Northern Chihuahuan Desert

USDA-ARS?s Scientific Manuscript database

Cryptobiotic soil crusts in arid regions contribute to ecosystem stability through increased water infiltration, soil aggregate stability, and nutrient cycling between the soil community and vascular plants. Natural gas mining involves removal of the topsoil, including surface crust, and storage of ...

Stabilization of Neem Oil Biodiesel with Corn Silk Extract during Long-term Storage.

PubMed

Ali, Rehab Farouk M; El-Anany, Ayman M

2017-02-01

The current study aimed to evaluate the antioxidant efficiency of different extracts of corn silk. In addition, the impact of corn silk extract on oxidative stability of neem biodiesel during storage was studied. The highest phenolics, DPPH radical scavenging and reducing power activities were recorded for methanol-water extract. The longest oxidation stability (10 h) was observed for biodiesel samples blended with 1000 ppm of corn silk extract (CSE). At the end of storage period the induction time of biodiesel samples mixed with 1000 ppm of CSE or butylated hydroxytoluene (BHT) were about 6.72 and 5.63 times as high as in biodiesel samples without antioxidants. Biodiesel samples blended with 1000 ppm of CSE had the lowest acidity at the end of storage period. Peroxide value of biodiesel samples containing 1000 ppm of CSE was about 4.28 times as low as in control sample without antioxidants.

Roasting pumpkin seeds and changes in the composition and oxidative stability of cold-pressed oils.

PubMed

Raczyk, Marianna; Siger, Aleksander; Radziejewska-Kubzdela, Elżbieta; Ratusz, Katarzyna; Rudzińska, Magdalena

2017-01-01

Pumpkin seed oil is valuable oil for its distinctive taste and aroma, as well as supposed health- promoting properties. The aim of this study was to investigate how roasting pumpkin seeds influences the physicochemical properties of cold-pressed oils. The fatty acid composition, content of phytosterols, carotenoids and tocopherols, oxidative stability and colour were determined in oils after cold pressing and storage for 3 months using GC-FID, GCxGC-ToFMS, HPLC, Rancimat and spectrophotometric methods. The results of this study indicate that the seed-roasting and storage process have no effect on the fatty acid composition of pumpkin seed oils, but does affect phytosterols and tocopherols. The carotenoid content decreased after storage. The colour of the roasted oil was darker and changed significantly during storage. Pumpkin oil obtained from roasted seeds shows better physicochemical properties and oxidative stability than oil from unroasted seeds.

Accurate prediction of vaccine stability under real storage conditions and during temperature excursions.

PubMed

Clénet, Didier

2018-04-01

Due to their thermosensitivity, most vaccines must be kept refrigerated from production to use. To successfully carry out global immunization programs, ensuring the stability of vaccines is crucial. In this context, two important issues are critical, namely: (i) predicting vaccine stability and (ii) preventing product damage due to excessive temperature excursions outside of the recommended storage conditions (cold chain break). We applied a combination of advanced kinetics and statistical analyses on vaccine forced degradation data to accurately describe the loss of antigenicity for a multivalent freeze-dried inactivated virus vaccine containing three variants. The screening of large amounts of kinetic models combined with a statistical model selection approach resulted in the identification of two-step kinetic models. Predictions based on kinetic analysis and experimental stability data were in agreement, with approximately five percentage points difference from real values for long-term stability storage conditions, after excursions of temperature and during experimental shipments of freeze-dried products. Results showed that modeling a few months of forced degradation can be used to predict various time and temperature profiles endured by vaccines, i.e. long-term stability, short time excursions outside the labeled storage conditions or shipments at ambient temperature, with high accuracy. Pharmaceutical applications of the presented kinetics-based approach are discussed. Copyright © 2018 The Author. Published by Elsevier B.V. All rights reserved.

Enhanced thermal conductivity of form-stable phase change composite with single-walled carbon nanotubes for thermal energy storage.

PubMed

Qian, Tingting; Li, Jinhong; Feng, Wuwei; Nian, Hong'en

2017-03-16

A striking contrast in the thermal conductivities of polyethylene glycol (PEG)/diatomite form-stable phase change composite (fs-PCC) with single-walled carbon nanotubes (SWCNs) as nano-additive has been reported in our present study. Compared to the pure PEG, the thermal conductivity of the prepared fs-PCC has increased from 0.24 W/mK to 0.87 W/Mk with a small SWCNs loading of 2 wt%. SWCNs are decorated on the inner surface of diatomite pores whilst retaining its porous structure. Compared to PEG/diatomite fs-PCC, the melting and solidification time of the PEG/diatomite/SWCNs fs-PCC are respectively decreased by 54.7% and 51.1%, and its thermal conductivity is 2.8 times higher. The composite can contain PEG as high as 60 wt% and maintain its original shape perfectly without any PEG leakage after subjected to 200 melt-freeze cycles. DSC results indicates that the melting point of the PEG/diatomite/SWCNs fs-PCC shifts to a lower temperature while the solidification point shifts to a higher temperature due to the presence of SWCNs. Importantly, the use of SWCNs is found to have clear beneficial effects for enhancing the thermal conductivity and thermal storage/release rates, without affecting thermal properties, chemical compatibility and thermal stability. The prepared PEG/diatomite/SWCNs fs-PCC exhibits excellent chemical and thermal durability and has potential application in solar thermal energy storage and solar heating.

Directly Grown Nanostructured Electrodes for High Volumetric Energy Density Binder-Free Hybrid Supercapacitors: A Case Study of CNTs//Li4Ti5O12

PubMed Central

Zuo, Wenhua; Wang, Chong; Li, Yuanyuan; Liu, Jinping

2015-01-01

Hybrid supercapacitor (HSC), which typically consists of a Li-ion battery electrode and an electric double-layer supercapacitor electrode, has been extensively investigated for large-scale applications such as hybrid electric vehicles, etc. Its application potential for thin-film downsized energy storage systems that always prefer high volumetric energy/power densities, however, has not yet been explored. Herein, as a case study, we develop an entirely binder-free HSC by using multiwalled carbon nanotube (MWCNT) network film as the cathode and Li4Ti5O12 (LTO) nanowire array as the anode and study the volumetric energy storage capability. Both the electrode materials are grown directly on carbon cloth current collector, ensuring robust mechanical/electrical contacts and flexibility. Our 3 V HSC device exhibits maximum volumetric energy density of ~4.38 mWh cm−3, much superior to those of previous supercapacitors based on thin-film electrodes fabricated directly on carbon cloth and even comparable to the commercial thin-film lithium battery. It also has volumetric power densities comparable to that of the commercial 5.5 V/100 mF supercapacitor (can be operated within 3 s) and has excellent cycling stability (~92% retention after 3000 cycles). The concept of utilizing binder-free electrodes to construct HSC for thin-film energy storage may be readily extended to other HSC electrode systems. PMID:25586374

Enhanced thermal conductivity of form-stable phase change composite with single-walled carbon nanotubes for thermal energy storage

NASA Astrophysics Data System (ADS)

Qian, Tingting; Li, Jinhong; Feng, Wuwei; Nian, Hong'En

2017-03-01

A striking contrast in the thermal conductivities of polyethylene glycol (PEG)/diatomite form-stable phase change composite (fs-PCC) with single-walled carbon nanotubes (SWCNs) as nano-additive has been reported in our present study. Compared to the pure PEG, the thermal conductivity of the prepared fs-PCC has increased from 0.24 W/mK to 0.87 W/Mk with a small SWCNs loading of 2 wt%. SWCNs are decorated on the inner surface of diatomite pores whilst retaining its porous structure. Compared to PEG/diatomite fs-PCC, the melting and solidification time of the PEG/diatomite/SWCNs fs-PCC are respectively decreased by 54.7% and 51.1%, and its thermal conductivity is 2.8 times higher. The composite can contain PEG as high as 60 wt% and maintain its original shape perfectly without any PEG leakage after subjected to 200 melt-freeze cycles. DSC results indicates that the melting point of the PEG/diatomite/SWCNs fs-PCC shifts to a lower temperature while the solidification point shifts to a higher temperature due to the presence of SWCNs. Importantly, the use of SWCNs is found to have clear beneficial effects for enhancing the thermal conductivity and thermal storage/release rates, without affecting thermal properties, chemical compatibility and thermal stability. The prepared PEG/diatomite/SWCNs fs-PCC exhibits excellent chemical and thermal durability and has potential application in solar thermal energy storage and solar heating.

Enhanced thermal conductivity of form-stable phase change composite with single-walled carbon nanotubes for thermal energy storage

PubMed Central

Qian, Tingting; Li, Jinhong; Feng, Wuwei; Nian, Hong’en

2017-01-01

A striking contrast in the thermal conductivities of polyethylene glycol (PEG)/diatomite form-stable phase change composite (fs-PCC) with single-walled carbon nanotubes (SWCNs) as nano-additive has been reported in our present study. Compared to the pure PEG, the thermal conductivity of the prepared fs-PCC has increased from 0.24 W/mK to 0.87 W/Mk with a small SWCNs loading of 2 wt%. SWCNs are decorated on the inner surface of diatomite pores whilst retaining its porous structure. Compared to PEG/diatomite fs-PCC, the melting and solidification time of the PEG/diatomite/SWCNs fs-PCC are respectively decreased by 54.7% and 51.1%, and its thermal conductivity is 2.8 times higher. The composite can contain PEG as high as 60 wt% and maintain its original shape perfectly without any PEG leakage after subjected to 200 melt-freeze cycles. DSC results indicates that the melting point of the PEG/diatomite/SWCNs fs-PCC shifts to a lower temperature while the solidification point shifts to a higher temperature due to the presence of SWCNs. Importantly, the use of SWCNs is found to have clear beneficial effects for enhancing the thermal conductivity and thermal storage/release rates, without affecting thermal properties, chemical compatibility and thermal stability. The prepared PEG/diatomite/SWCNs fs-PCC exhibits excellent chemical and thermal durability and has potential application in solar thermal energy storage and solar heating. PMID:28300191

Stability and changes in astaxanthin ester composition from Haematococcus pluvialis during storage

NASA Astrophysics Data System (ADS)

Miao, Fengping; Geng, Yahong; Lu, Dayan; Zuo, Jincheng; Li, Yeguang

2013-11-01

In this paper, we investigated the effects of temperature, oxygen, antioxidants, and corn germ oil on the stability of astaxanthin from Haematococcus pluvialis under different storage conditions, and changes in the composition of astaxanthin esters during storage using high performance liquid chromatography and spectrophotometry. Oxygen and high temperatures (22-25°C) significantly reduced the stability of astaxanthin esters. Corn germ oil and antioxidants (ascorbic acid and vitamin E) failed to protect astaxanthin from oxidation, and actually significantly increased the instability of astaxanthin. A change in the relative composition of astaxanthin esters was observed after 96 weeks of long-term storage. During storage, the relative amounts of free astaxanthin and astaxanthin monoesters declined, while the relative amount of astaxanthin diesters increased. Thus, the ratio of astaxanthin diester to monoester increased, and this ratio could be used to indicate if astaxanthin esters have been properly preserved. If the ratio is greater than 0.2, it suggests that the decrease in astaxanthin content could be higher than 20%. Our results show that storing algal powder from H. pluvialis or other natural astaxanthin products under vacuum and in the dark below 4°C is the most economical and applicable storage method for the large-scale production of astaxanthin from H. pluvialis. This storage method can produce an astaxanthin preservation rate of at least 80% after 96 weeks of storage.

Dc microgrid stabilization through fuzzy control of interleaved, heterogeneous storage elements

NASA Astrophysics Data System (ADS)

Smith, Robert David

As microgrid power systems gain prevalence and renewable energy comprises greater and greater portions of distributed generation, energy storage becomes important to offset the higher variance of renewable energy sources and maximize their usefulness. One of the emerging techniques is to utilize a combination of lead-acid batteries and ultracapacitors to provide both short and long-term stabilization to microgrid systems. The different energy and power characteristics of batteries and ultracapacitors imply that they ought to be utilized in different ways. Traditional linear controls can use these energy storage systems to stabilize a power grid, but cannot effect more complex interactions. This research explores a fuzzy logic approach to microgrid stabilization. The ability of a fuzzy logic controller to regulate a dc bus in the presence of source and load fluctuations, in a manner comparable to traditional linear control systems, is explored and demonstrated. Furthermore, the expanded capabilities (such as storage balancing, self-protection, and battery optimization) of a fuzzy logic system over a traditional linear control system are shown. System simulation results are presented and validated through hardware-based experiments. These experiments confirm the capabilities of the fuzzy logic control system to regulate bus voltage, balance storage elements, optimize battery usage, and effect self-protection.

Metallic CoS2 nanowire electrodes for high cycling performance supercapacitors

NASA Astrophysics Data System (ADS)

Ren, Ren; Faber, Matthew S.; Dziedzic, Rafal; Wen, Zhenhai; Jin, Song; Mao, Shun; Chen, Junhong

2015-12-01

We report metallic cobalt pyrite (CoS2) nanowires (NWs) prepared directly on current collecting electrodes, e.g., carbon cloth or graphite disc, for high-performance supercapacitors. These CoS2 NWs have a variety of advantages for supercapacitor applications. Because the metallic CoS2 NWs are synthesized directly on the current collector, the good electrical connection enables efficient charge transfer between the active CoS2 materials and the current collector. In addition, the open spaces between the sea urchin structure NWs lead to a large accessible surface area and afford rapid mass transport. Moreover, the robust CoS2 NW structure results in high stability of the active materials during long-term operation. Electrochemical characterization reveals that the CoS2 NWs enable large specific capacitance (828.2 F g-1 at a scan rate of 0.01 V s-1) and excellent long term cycling stability (0-2.5% capacity loss after 4250 cycles at 5 A g-1) for pseudocapacitors. This example of metallic CoS2 NWs for supercapacitor applications expands the opportunities for transition metal sulfide-based nanostructures in emerging energy storage applications.

Metallic CoS₂ nanowire electrodes for high cycling performance supercapacitors.

PubMed

Ren, Ren; Faber, Matthew S; Dziedzic, Rafal; Wen, Zhenhai; Jin, Song; Mao, Shun; Chen, Junhong

2015-12-11

We report metallic cobalt pyrite (CoS2) nanowires (NWs) prepared directly on current collecting electrodes, e.g., carbon cloth or graphite disc, for high-performance supercapacitors. These CoS2 NWs have a variety of advantages for supercapacitor applications. Because the metallic CoS2 NWs are synthesized directly on the current collector, the good electrical connection enables efficient charge transfer between the active CoS2 materials and the current collector. In addition, the open spaces between the sea urchin structure NWs lead to a large accessible surface area and afford rapid mass transport. Moreover, the robust CoS2 NW structure results in high stability of the active materials during long-term operation. Electrochemical characterization reveals that the CoS2 NWs enable large specific capacitance (828.2 F g(-1) at a scan rate of 0.01 V s(-1)) and excellent long term cycling stability (0-2.5% capacity loss after 4250 cycles at 5 A g(-1)) for pseudocapacitors. This example of metallic CoS2 NWs for supercapacitor applications expands the opportunities for transition metal sulfide-based nanostructures in emerging energy storage applications.

Novel hydrazones - antioxidant potential and stabilization via polysaccharide particles

NASA Astrophysics Data System (ADS)

Hristova-Avakumova, N.; Nikolova-Mladenova, B.; Yoncheva, K.; Hadjimitova, V.

2017-01-01

In this study, we aimed to: i) determine the impact of three new isonicotinoyl hydrazones derivatives in in vitro systems used to investigate free radical processes - radical scavenging approach (ABTS and DPPH) and iron induced peroxidation in lipid containing model systems and ii) evaluate the potential of polysaccharide-based particles to act as protective carriers preserving the antioxidant activity (AOA) of the tested compounds. The tested compounds revealed excellent antioxidant effectiveness in the ABTS system. In the DPPH radical scavenging assay the compounds exhibited very weak or absence of AOA. The data from the iron induced peroxidation methods disclosed better antioxidant properties of the derivatives in the system containing egg yolk homogenate which is more plausible compared to the lecithin containing one. The incorporation of a bromine atom on 5th position in salicylaldehyde moiety is associated with diminishment of the radical scavenging activity in the systems containing stable free radicals but its AOA reduction after encapsulation during the storage was only 9.17%. The obtained data indicate that compounds have proven themselves as promising candidates for further evaluation as antioxidant agents. Their encapsulation in chitosan-alginate particles could be a useful approach for improving the stability of their antioxidant properties.

Novel iron oxide nanotube arrays as high-performance anodes for lithium ion batteries

NASA Astrophysics Data System (ADS)

Zhong, Yuan; Fan, Huiqing; Chang, Ling; Shao, Haibo; Wang, Jianming; Zhang, Jianqing; Cao, Chu-nan

2015-11-01

Nanostructured iron oxides can be promising anode materials for lithium ion batteries (LIBs). However, improvement on the rate capability and/or electrochemical cycling stability of iron oxide anode materials remains a key challenge because of their poor electrical conductivities and large volume expansion during cycling. Herein, the vertically aligned arrays of one-dimensional (1D) iron oxide nanotubes with 5.8 wt% carbon have been fabricated by a novel surfactant-free self-corrosion process and subsequent thermal treatment. The as-fabricated nanotube array electrode delivers a reversible capacity of 932 mAh g-1 after 50 charge-discharge cycles at a current of 0.6 A g-1. The electrode still shows a reversible capacity of 610 mAh g-1 even at a very high rate (8.0 A g-1), demonstrating its prominent rate capability. Furthermore, the nanotube array electrode also exhibits the excellent electrochemical cycling stability with a reversible capacity of 880 mAh g-1 after 500 cycles at a current of 4 A g-1. The nanotube array electrode with superior lithium storage performance reveals the promising potential as a high-performance anode for LIBs.

Evaluation of Graphene/WO3 and Graphene/CeO x Structures as Electrodes for Supercapacitor Applications

NASA Astrophysics Data System (ADS)

Chaitoglou, Stefanos; Amade, Roger; Bertran, Enric

2017-12-01

The combination of graphene with transition metal oxides can result in very promising hybrid materials for use in energy storage applications thanks to its intriguing properties, i.e., highly tunable surface area, outstanding electrical conductivity, good chemical stability, and excellent mechanical behavior. In the present work, we evaluate the performance of graphene/metal oxide (WO3 and CeO x ) layered structures as potential electrodes in supercapacitor applications. Graphene layers were grown by chemical vapor deposition (CVD) on copper substrates. Single and layer-by-layer graphene stacks were fabricated combining graphene transfer techniques and metal oxides grown by magnetron sputtering. The electrochemical properties of the samples were analyzed and the results suggest an improvement in the performance of the device with the increase in the number of graphene layers. Furthermore, deposition of transition metal oxides within the stack of graphene layers further improves the areal capacitance of the device up to 4.55 mF/cm2, for the case of a three-layer stack. Such high values are interpreted as a result of the copper oxide grown between the copper substrate and the graphene layer. The electrodes present good stability for the first 850 cycles before degradation.

3D architecture of a graphene/CoMoO(4) composite for asymmetric supercapacitors usable at various temperatures.

PubMed

Jiang, Yaru; Zheng, Xin; Yan, Xiaoqin; Li, Yong; Zhao, Xuan; Zhang, Yue

2017-05-01

Designing and optimizing the electrode materials and studying the electrochemical performance or cycle life of the supercapacitor under different working conditions are crucial to its practical application. Herein, we proposed a rational design of 3D-graphene/CoMoO 4 nanoplates by a facile two-step hydrothermal method. Owing to the high electron transfer rate of graphene and the high activity of the CoMoO 4 nanoplates, the three-dimensional electrode architectures achieved remarkable electrochemical performances with high areal specific capacitance (1255.24F/g at 1A/g) and superior cycling stability (91.3% of the original specific capacitance after 3000 cycles at 1A/g). The all-solid-state asymmetric supercapacitor composed of 3D-graphene/CoMoO 4 and activated carbon (AC) exhibited a specific capacitance of 109F/g at 0.2A/g and an excellent cycling stability with only 12.1% of the initial specific capacitance off after 3000 cycles at 2A/g. The effects of temperature and charge-discharge current densities on the charge storage capacity of the supercapacitor were also investigated in detail for practical applications. Copyright © 2017 Elsevier Inc. All rights reserved.

Three-dimensional hierarchical and interconnected honeycomb-like porous carbon derived from pomelo peel for high performance supercapacitors

NASA Astrophysics Data System (ADS)

Liu, Jingyuan; Li, Hongpeng; Zhang, Hongsen; Liu, Qi; Li, Rumin; Li, Bin; Wang, Jun

2018-01-01

The urgent need for sustainable development of human society has forced material scientists to explore novel materials starting from cheap natural precursors for next-generation energy storage devices by using environmentally friendly strategies. In this work, heteroatom-functionalized porous carbonaceous materials with 3D hierarchical and interconnected honeycomb-like structure have been successfully synthesized by using waste biomass pomelo peel as raw material through the combination of hydrothermal carbonization and followed KOH activation procedure. Benefiting from the unique honeycomb-like structure and high specific surface area, the as-obtained carbon material exhibits satisfactory capacitive behavior: 374 F/g at 0.1 A/g; excellent cycling stability of 92.5% capacitance retention over continuous 5000 cycles. More importantly, the as-assembled symmetric supercapacitors based on as-prepared electrode material can deliver high gravimetric and volumetric energy density of 20 W h/kg and 18.7 W h/L in 6 M KOH, respectively, as well as outstanding cycling stability. The obtained results demonstrate the possibility for taking full advantage of sustainable and large scale advanced carbon materials by choosing waste biomass, particularly the pomelo peel as a raw material.

Unique Cobalt Sulfide/Reduced Graphene Oxide Composite as an Anode for Sodium-Ion Batteries with Superior Rate Capability and Long Cycling Stability.

PubMed

Peng, Shengjie; Han, Xiaopeng; Li, Linlin; Zhu, Zhiqiang; Cheng, Fangyi; Srinivansan, Madhavi; Adams, Stefan; Ramakrishna, Seeram

2016-03-09

Exploitation of high-performance anode materials is essential but challenging to the development of sodium-ion batteries (SIBs). Among all proposed anode materials for SIBs, sulfides have been proved promising candidates due to their unique chemical and physical properties. In this work, a facile solvothermal method to in situ decorate cobalt sulfide (CoS) nanoplates on reduced graphene oxide (rGO) to build CoS@rGO composite is described. When evaluated as anode for SIBs, an impressive high specific capacity (540 mAh g(-1) at 1 A g(-1) ), excellent rate capability (636 mAh g(-1) at 0.1 A g(-1) and 306 mAh g(-1) at 10 A g(-1)), and extraordinarily cycle stability (420 mAh g(-1) at 1 A g(-1) after 1000 cycles) have been demonstrated by CoS@rGO composite for sodium storage. The synergetic effect between the CoS nanoplates and rGO matrix contributes to the enhanced electrochemical performance of the hybrid composite. The results provide a facile approach to fabricate promising anode materials for high-performance SIBs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In-situ carbon-coated Na2FeP2O7 anchored in three-dimensional reduced graphene oxide framework as a durable and high-rate sodium-ion battery cathode

NASA Astrophysics Data System (ADS)

Chen, Xiaobin; Du, Ke; Lai, Yanqing; Shang, Guozhi; Li, Huangxu; Xiao, Zhiwei; Chen, Yuxiang; Li, Junming; Zhang, Zhian

2017-07-01

Na2FeP2O7, which is considered as a promising cathode for sodium ion batteries (SIBs) on account of its economical efficiency and outstanding thermal stability, has been widely studied for the purpose of enhancing its electronic conductivity and interface ion transportation. In this paper, a double-carbon synergistically modified strategy was firstly introduced to facilitate the electrochemical performance of Na2FeP2O7. Na2FeP2O7 particles are enwrapped in situ by a carbon layer and further anchored in reduced graphene oxide (RGO) framework through a facile urea-nitrate combustion method. Consequently, the excellent rate performance and durable cycle stability of this compound are identified, which exhibits a reversible sodium storage capacity of 65 mAh g-1 at a current density of 10 C and no obvious decay in capacity after circling for 300 cycles at 1 C. What's more, no drastic degradation in capacity is observed when the cycling current density is brought back to high rates after cycling for more than 360 cycles at various rates.

Self-assembled organic-inorganic hybrid glucoamylase nanoflowers with enhanced activity and stability.

PubMed

Nadar, Shamraja S; Gawas, Sarita D; Rathod, Virendra K

2016-11-01

An organic-inorganic hybrid glucoamylase nanoflower was prepared in single pot by simple, facile and highly efficient method. The stepwise formation of enzyme-embedded hybrid nanoflowers and influence of experimental parameters viz. pH of solution mixture, enzyme and copper ion concentration on the activity of prepared hybrid nanoflowers were systematically investigated. The self-assembled hybrid glucoamylase nanoflowers were synthesized by mixing aqueous solution of copper sulphate (200mM) with PBS (pH 7.5, 5mM) containing glucoamylase (1mg/mL) in 24h at room temperature. These prepared nanoflowers were further characterized by FT-IR, SEM and XRD. The hybrid nanoflowers exhibited 204% enhanced activity recovery and two folds improvement in thermal stability in terms of half-life (in the range of 50-70°C) with respect to the free form. The hybrid glucoamylase nanoflowers retained 70% residual activity after eight successive cycles indicating their excellent durability. Additionally, the nanoflowers retained up to 91% residual activity upto 25 days of storage. Moreover, the conformational changes occurred in glucoamylase structure after preparing hybrid nanoflowers were evaluated by FT-IR spectroscopy data tools. Copyright © 2016 Elsevier B.V. All rights reserved.

Nickel/silicon core/shell nanosheet arrays as electrode materials for lithium ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, X.H., E-mail: drhuangxh@hotmail.com; Zhang, P.; Wu, J.B.

Highlights: • Ni nanosheet arrays is the core and Si layer is the shell. • Ni nanosheet arrays act as a three-dimensional current collector to support Si. • Ni nanosheet arrays can improve the conductivity and stability of the electrode. • Ni/Si nanosheet arrays exhibit excellent cyclic and rate performance. - Abstract: Ni/Si core/shell nanosheet arrays are proposed to enhance the electrochemical lithium-storage properties of silicon. The arrays are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The arrays are micro-sized in height, which are constructed by interconnected Ni nanosheet as themore » core and Si coating layer as the shell. The electrochemical properties as anode materials of lithium ion batteries are investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge tests. The arrays can achieve high reversible capacity, good cycle stability and high rate capability. It is believed that the enhanced electrochemical performance is attributed to the electrode structure, because the interconnected Ni nanosheet can act as a three-dimensional current collector, and it has the ability of improving the electrode conductivity, enlarging the electrochemical reaction interface, and suppressing the electrode pulverization.« less

Benzothienobenzothiophene-based conjugated oligomers as semiconductors for stable organic thin-film transistors.

PubMed

Yu, Han; Li, Weili; Tian, Hongkun; Wang, Haibo; Yan, Donghang; Zhang, Jingping; Geng, Yanhou; Wang, Fosong

2014-04-09

Two benzothienobenzothiophene (BTBT)-based conjugated oligomers, i.e., 2,2'-bi[1]benzothieno[3,2-b][1]benzothiophene (1) and 5,5'-bis([1]benzothieno[3,2-b][1]benzothiophen-2-yl)-2,2'-bithiophene (2), were prepared and characterized. Both oligomers exhibit excellent thermal stability, with 5% weight-loss temperatures (T(L)) above 370 °C; no phase transition was observed before decomposition. The highest occupied molecular orbital (HOMO) levels of 1 and 2 are -5.3 and -4.9 eV, respectively, as measured by ultraviolet photoelectron spectroscopy. Thin-film X-ray diffraction and atomic force microscopy characterizations indicate that both oligomers form highly crystalline films with large domain sizes on octadecyltrimethoxysilane-modified substrates. Organic thin-film transistors with top-contact and bottom-gate geometry based on 1 and 2 exhibited mobilities up to 2.12 cm(2)/V·s for 1 and 1.39 cm(2)/V·s for 2 in an ambient atmosphere. 1-based devices exhibited great air and thermal stabilities, as evidenced by the slight performance degradation after 2 months of storage under ambient conditions and after thermal annealing at temperatures below 250 °C.

Self-Assembly DNA Polyplex Vaccine inside Dissolving Microneedles for High-Potency Intradermal Vaccination.

PubMed

Liao, Jing-Fong; Lee, Jin-Ching; Lin, Chun-Kuang; Wei, Kuo-Chen; Chen, Pin-Yuan; Yang, Hung-Wei

2017-01-01

The strong immunogenicity induction is the powerful weapon to prevent the virus infections. This study demonstrated that one-step synthesis of DNA polyplex vaccine in microneedle (MN) patches can induce high immunogenicity through intradermal vaccination and increase the vaccine stability for storage outside the cold chain. More negative charged DNA vaccine was entrapped into the needle region of MNs followed by DNA polyplex formation with branched polyethylenimine (bPEI) pre-coated in the cavities of polydimethylsiloxane (PDMS) molds that can deliver more DNA vaccine to immune-cell rich epidermis with high transfection efficiency. Our data in this study support the safety and immunogenicity of the MN-based vaccine; the MN patch delivery system induced an immune response 3.5-fold as strong as seen with conventional intramuscular administration; the DNA polyplex formulation provided excellent vaccine stability at high temperature (could be stored at 45ºC for at least 4 months); the DNA vaccine is expected to be manufactured at low cost and not generate sharps waste. We think this study is significant to public health because there is a pressing need for an effective vaccination in developing countries.

Bioinspired Hierarchical Nanofibrous Silver-Nanoparticle/Anatase-Rutile-Titania Composite as an Anode Material for Lithium-Ion Batteries.

PubMed

Luo, Yan; Li, Jiao; Huang, Jianguo

2016-11-29

A new bioinspired hierarchical nanofibrous silver-nanoparticle/anatase-rutile-titania (Ag-NP/A-R-titania) composite was fabricated by employing a natural cellulose substance (e.g., commercial laboratory cellulose filter paper) as the structural scaffold template, which was composed of anatase-phase titania (A-titania) nanotubes with rutile-phase titania (R-titania) nanoneedles grown on the surfaces and further silver nanoparticles (AgNPs) immobilized thereon. As it was employed as an anode material for lithium-ion batteries (LIBs), high reversible capacity, enhanced rate performance, and excellent cycling stability were achieved as compared with those of the corresponding cellulose-substance-derived nanotubular A-titania, R-titania, heterogeneous anatase/rutile titania (A-R-titania) composite, and commercial P25 powder. This benefited from its unique porous cross-linked three-dimensional structure inherited from the initial cellulose substance scaffold, which enhances the sufficient electrode/electrolyte contact, relieves the severe volume change upon cycling, and improves the amount of lithium-ion storage; moreover, the high loading content of the silver component in the composite improves the electrical conductivity of the electrode. The structural integrity of the composite was maintained upon long-term charge/discharge cycling, indicating its significant stability.

Plutonium inventories for stabilization and stabilized materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, A.K.

1996-05-01

The objective of the breakout session was to identify characteristics of materials containing plutonium, the need to stabilize these materials for storage, and plans to accomplish the stabilization activities. All current stabilization activities are driven by the Defense Nuclear Facilities Safety Board Recommendation 94-1 (May 26, 1994) and by the recently completed Plutonium ES&H Vulnerability Assessment (DOE-EH-0415). The Implementation Plan for accomplishing stabilization of plutonium-bearing residues in response to the Recommendation and the Assessment was published by DOE on February 28, 1995. This Implementation Plan (IP) commits to stabilizing problem materials within 3 years, and stabilizing all other materials withinmore » 8 years. The IP identifies approximately 20 metric tons of plutonium requiring stabilization and/or repackaging. A further breakdown shows this material to consist of 8.5 metric tons of plutonium metal and alloys, 5.5 metric tons of plutonium as oxide, and 6 metric tons of plutonium as residues. Stabilization of the metal and oxide categories containing greater than 50 weight percent plutonium is covered by DOE Standard {open_quotes}Criteria for Safe Storage of Plutonium Metals and Oxides{close_quotes} December, 1994 (DOE-STD-3013-94). This standard establishes criteria for safe storage of stabilized plutonium metals and oxides for up to 50 years. Each of the DOE sites and contractors with large plutonium inventories has either started or is preparing to start stabilization activities to meet these criteria.« less

Phytosterol structured algae oil nanoemulsions and powders: improving antioxidant and flavor properties.

PubMed

Chen, Xiao-Wei; Chen, Ya-Jun; Wang, Jin-Mei; Guo, Jian; Yin, Shou-Wei; Yang, Xiao-Quan

2016-09-14

Algae oil, enriched with omega-3 long-chain polyunsaturated fatty acids (ω-3 LC-PUFA), is known for its health benefits. However, protection against lipid oxidation as well as masking of unpleasant fishy malodors in algae oil enriched foods is a big challenge to achieve. In this study, we firstly achieved a one-pot ultrasound emulsification strategy (alternative heating-homogenization) to prepare phytosterol structured thermosensitive algae oil-in-water nanoemulsion stabilized by quillaja saponin. After spray drying, the resulting algae oil powders from the structured nanoemulsion templates exhibit an excellent reconstructed behavior, even after 30 d of storage. Furthermore, an enhanced oxidative stability was obtained by reducing both the primary and secondary oxidation products through formulation with β-sitosterol and γ-oryzanol, which are natural antioxidants. Following the results of headspace volatiles using dynamic headspace-gas chromatography-mass spectrometry (DHS-GC-MS), it was clear that the structured algae oil-loaded nanoemulsion and powder had lower levels of fishy off-flavour (e.g., (Z)-heptenal, decanal, ethanone, and hexadecenoic acid), whereas the control emulsion and oil powder without structure performed worse. This study demonstrated that the structure from phytosterols is an effective strategy to minimize the fishy off-flavour and maximize oxidative stability of both algae oil nanoemulsions and spray-dried powders, and opens up the possibility of formulation design in polyunsaturated oil encapsulates as novel delivery systems to apply in functional foods and beverages.

Promoting the ambient-condition stability of Zr-doped barium cerate: Toward robust solid oxide fuel cells and hydrogen separation in syngas

NASA Astrophysics Data System (ADS)

Yang, Ying; Zeng, Yimin; Amirkhiz, Babak S.; Luo, Jing-Li; Yan, Ning

2018-02-01

Increasing the stability of perovskite proton conductor against atmospheric CO2 and moisture attack at ambient conditions might be equally important as that at the elevated service temperatures. It can ease the transportation and storage of materials, potentially reducing the maintenance cost of the integral devices. In this work, we initially examined the surface degradation behaviors of various Zr-doped barium cerates (BaCe0.7Zr0.1Y0.1Me0.1O3) using XRD, SEM, STEM and electron energy loss spectroscopy. Though that the typical lanthanide (Y, Yb and Gd) and In incorporated Zr-doped cerates well resisted CO2-induced carbonation in air at elevated temperatures, they were unfortunately vulnerable at ambient conditions, suffering slow decompositions at the surface. Conversely, Sn doped samples (BCZYSn) were robust at both conditions yet showed high protonic conductivity. Thanks to that, the anode supported solid oxide fuel cells equipped with BCZYSn electrolyte delivered a maximum power density of 387 mW cm-2 at 600 °C in simulated coal-derived syngas. In the hydrogen permeation test using BCZYSn based membrane, the H2 flux reached 0.11 mL cm-2 min-1 at 850 °C when syngas was the feedstock. Both devices demonstrated excellent stability in the presence of CO2 in the syngas.

Improved Ionic Diffusion through the Mesoporous Carbon Skin on Silicon Nanoparticles Embedded in Carbon for Ultrafast Lithium Storage.

PubMed

An, Geon-Hyoung; Kim, Hyeonjin; Ahn, Hyo-Jin

2018-02-21

Because of their combined effects of outstanding mechanical stability, high electrical conductivity, and high theoretical capacity, silicon (Si) nanoparticles embedded in carbon are a promising candidate as electrode material for practical utilization in Li-ion batteries (LIBs) to replace the conventional graphite. However, because of the poor ionic diffusion of electrode materials, the low-grade ultrafast cycling performance at high current densities remains a considerable challenge. In the present study, seeking to improve the ionic diffusion, we propose a novel design of mesoporous carbon skin on the Si nanoparticles embedded in carbon by hydrothermal reaction, poly(methyl methacrylate) coating process, and carbonization. The resultant electrode offers a high specific discharge capacity with excellent cycling stability (1140 mA h g -1 at 100 mA g -1 after 100 cycles), superb high-rate performance (969 mA h g -1 at 2000 mA g -1 ), and outstanding ultrafast cycling stability (532 mA h g -1 at 2000 mA g -1 after 500 cycles). The battery performances are surpassing the previously reported results for carbon and Si composite-based electrodes on LIBs. Therefore, this novel approach provides multiple benefits in terms of the effective accommodation of large volume expansions of the Si nanoparticles, a shorter Li-ion diffusion pathway, and stable electrochemical conditions from a faster ionic diffusion during cycling.

Color stability of microfilled, microhybrid and nanocomposite resins--an in vitro study.

PubMed

Nasim, Iffat; Neelakantan, Prasanna; Sujeer, R; Subbarao, C V

2010-01-01

The aim of this study was to evaluate the effect of two beverages-Tea and Pepsi on the color stability of three different composite resins after a period of 7 and 30 days. Color stability of a microfilled, microhybrid and nanocomposite was evaluated after storage in Tea, a carbonated drink or Distilled Water for 7 and 30 days. Color measurement was done using reflectance spectrophotometer based on the CIE L*a*b* color scale. Mean values of the different groups were compared using three-way analysis of variance and multiple comparisons of the mean values were done using Tukey-Kramer test with 0.05 as significance level. All tested resin composites showed color change after a period of 7 and 30 days. The color change exhibited by all three groups was significantly different for all three beverages studied, at both time periods (p<0.05). Amongst the resin composites studied microhybrid composite was found to be more color stable. The microfilled composite discolored most in Distilled Water and Pepsi at the 7th and 30th day. The nanocomposite discolored most in Tea at 7th and 30th day. All efforts should be made to minimize discoloration of composite restorations by adopting excellent polishing techniques. Patients should also be educated on the possibility of the restoration to undergo staining under the influence of beverages. Copyright © 2010 Elsevier Ltd. All rights reserved.

Amide-Catalyzed Phase-Selective Crystallization Reduces Defect Density in Wide-Bandgap Perovskites.

PubMed

Kim, Junghwan; Saidaminov, Makhsud I; Tan, Hairen; Zhao, Yicheng; Kim, Younghoon; Choi, Jongmin; Jo, Jea Woong; Fan, James; Quintero-Bermudez, Rafael; Yang, Zhenyu; Quan, Li Na; Wei, Mingyang; Voznyy, Oleksandr; Sargent, Edward H

2018-03-01

Wide-bandgap (WBG) formamidinium-cesium (FA-Cs) lead iodide-bromide mixed perovskites are promising materials for front cells well-matched with crystalline silicon to form tandem solar cells. They offer avenues to augment the performance of widely deployed commercial solar cells. However, phase instability, high open-circuit voltage (V oc ) deficit, and large hysteresis limit this otherwise promising technology. Here, by controlling the crystallization of FA-Cs WBG perovskite with the aid of a formamide cosolvent, light-induced phase segregation and hysteresis in perovskite solar cells are suppressed. The highly polar solvent additive formamide induces direct formation of the black perovskite phase, bypassing the yellow phases, thereby reducing the density of defects in films. As a result, the optimized WBG perovskite solar cells (PSCs) (E g ≈ 1.75 eV) exhibit a high V oc of 1.23 V, reduced hysteresis, and a power conversion efficiency (PCE) of 17.8%. A PCE of 15.2% on 1.1 cm 2 solar cells, the highest among the reported efficiencies for large-area PSCs having this bandgap is also demonstrated. These perovskites show excellent phase stability and thermal stability, as well as long-term air stability. They maintain ≈95% of their initial PCE after 1300 h of storage in dry air without encapsulation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A High Capacity, Good Safety and Low Cost Na2FeSiO4-Based Cathode for Rechargeable Sodium-Ion Battery.

PubMed

Guan, Wenhao; Pan, Bin; Zhou, Peng; Mi, Jinxiao; Zhang, Dan; Xu, Jiacheng; Jiang, Yinzhu

2017-07-12

Rechargeable sodium-ion batteries (SIBs) are receiving intense interest because the resource abundance of sodium and its lithium-like chemistry make them low cost alternatives to the prevailing lithium-ion batteries in large-scale energy storage devices. Two typical classes of materials including transition metal oxides and polyanion compounds have been under intensive investigation as cathodes for SIBs; however, they are still limited to poor stability or low capacity of the state-of-art. Herein, we report a low cost carbon-coated Na 2 FeSiO 4 with simultaneous high capacity and good stability, owing to the highly pure Na-rich triclinic phase and the carbon-incorporated three-dimensional network morphology. The present carbon-coated Na 2 FeSiO 4 demonstrates the highest reversible capacity of 181.0 mAh g -1 to date with multielectron redox reaction that occurred among various polyanion-based SIBs cathodes, which achieves a close-to-100% initial Coulombic efficiency and a stable cycling with 88% capacity retention up to 100 cycles. In addition, such an electrode shows excellent stability either charged at a high voltage of 4.5 V or heated up to 800 °C. The present work might open up the possibility for developing high capacity, good safety and low cost polyanion-based cathodes for rechargeable SIBs.

Natural lipids-based NLC containing lidocaine: from pre-formulation to in vivo studies.

PubMed

Ribeiro, Lígia N M; Breitkreitz, Márcia C; Guilherme, Viviane A; da Silva, Gustavo H R; Couto, Verônica M; Castro, Simone R; de Paula, Bárbara O; Machado, Daisy; de Paula, Eneida

2017-08-30

In a nanotechnological approach we have investigated the use of natural lipids in the preparation of nanostructured lipid carriers (NLC). Three different NLC composed of copaiba oil and beeswax, sweet almond oil and shea butter, and sesame oil and cocoa butter as structural matrices were optimized using factorial analysis; Pluronic® 68 and lidocaine (LDC) were used as the colloidal stabilizer and model encapsulated drug, respectively. The optimal formulations were characterized by different techniques (IR-ATR, DSC, and TEM), and their safety and efficacy were also tested. These nanocarriers were able to upload high amounts of the anesthetic with a sustained in vitro release profile for 24h. The physicochemical stability in terms of size (nm), PDI, zeta potential (mV), pH, nanoparticle concentration (particles/mL), and visual inspection was followed during 12months of storage at 25°C. The formulations exhibited excellent structural properties and stability. They proved to be nontoxic in vitro (cell viability tests with Balb/c 3T3 fibroblasts) and significantly improved the in vivo effects of LDC, over the heart rate of zebra fish larvae and in the blockage of sciatic nerve in mice. The results from this study support that the proper combination of natural excipients is promising in DDS, taking advantage of the biocompatibility, low cost, and diversity of lipids. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of a high-moisture stabilization strategy for harvested microalgae blended with herbaceous biomass: Part II — Techno-economic assessment

DOE PAGES

Wendt, Lynn M.; Wahlen, Bradley D.; Li, Chenlin; ...

2017-04-26

The seasonal variability in algal biomass production and its susceptibility to rapid degradation increases uncertainty in algal productivity and increases risks to feedstock supply for conversion. During summer months when algal biomass productivity is highest, production could exceed conversion capacity, resulting in delayed processing and risk of biomass degradation. Drying algae for preservation is energy-intensive and can account for over 50% of the total energy demand in algae preprocessing. Anaerobic wet storage – ensiling – is a widely used storage technique for stabilization of high moisture forage. Wet stabilization of algae eliminates the need for drying, and blending with herbaceousmore » biomass allows for the utilization of the silage industry’s existing harvest, handling and storage infrastructure. A storage facility co-located with the algae production and conversion operations was designed to stabilize algal biomass produced in excess of conversion capacity during summer months for use in the winter when algal biomass production is reduced. Techno-economic assessment of the costs associated with ensiling algae and corn stover blends suggest it to be a cost effective approach, compared to drying. In a high algal biomass productivity scenario, costs of wet storage ($/gallon diesel) were only 65% of the cost of drying. When a reduced algal biomass productivity scenario was considered, the stored blend was able to cost-effectively provide sufficient biomass such that winter production in the algal ponds could cease, meanwhile incurring only 91% of the costs of drying; such an approach would facilitate algal biomass production in northern latitudes. Moreover, the wet storage approaches requiring only 8-10% of the total energy consumption and releasing only 20-25% of the greenhouse gasses when compared to a natural-gas based drying approach for microalgae stabilization.« less

Sample preparation and storage can change arsenic speciation in human urine.

PubMed

Feldmann, J; Lai, V W; Cullen, W R; Ma, M; Lu, X; Le, X C

1999-11-01

Stability of chemical speciation during sample handling and storage is a prerequisite to obtaining reliable results of trace element speciation analysis. There is no comprehensive information on the stability of common arsenic species, such as inorganic arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid, dimethylarsinic acid, and arsenobetaine, in human urine. We compared the effects of the following storage conditions on the stability of these arsenic species: temperature (25, 4, and -20 degrees C), storage time (1, 2, 4, and 8 months), and the use of additives (HCl, sodium azide, benzoic acid, benzyltrimethylammonium chloride, and cetylpyridinium chloride). HPLC with both inductively coupled plasma mass spectrometry and hydride generation atomic fluorescence detection techniques were used for the speciation of arsenic. We found that all five of the arsenic species were stable for up to 2 months when urine samples were stored at 4 and -20 degrees C without any additives. For longer period of storage (4 and 8 months), the stability of arsenic species was dependent on urine matrices. Whereas the arsenic speciation in some urine samples was stable for the entire 8 months at both 4 and -20 degrees C, other urine samples stored under identical conditions showed substantial changes in the concentration of As(III), As(V), monomethylarsonic acid, and dimethylarsinic acid. The use of additives did not improve the stability of arsenic speciation in urine. The addition of 0.1 mol/L HCl (final concentration) to urine samples produced relative changes in inorganic As(III) and As(V) concentrations. Low temperature (4 and -20 degrees C) conditions are suitable for the storage of urine samples for up to 2 months. Untreated samples maintain their concentration of arsenic species, and additives have no particular benefit. Strong acidification is not appropriate for speciation analysis.

Evaluation of a high-moisture stabilization strategy for harvested microalgae blended with herbaceous biomass: Part II — Techno-economic assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wendt, Lynn M.; Wahlen, Bradley D.; Li, Chenlin

The seasonal variability in algal biomass production and its susceptibility to rapid degradation increases uncertainty in algal productivity and increases risks to feedstock supply for conversion. During summer months when algal biomass productivity is highest, production could exceed conversion capacity, resulting in delayed processing and risk of biomass degradation. Drying algae for preservation is energy-intensive and can account for over 50% of the total energy demand in algae preprocessing. Anaerobic wet storage – ensiling – is a widely used storage technique for stabilization of high moisture forage. Wet stabilization of algae eliminates the need for drying, and blending with herbaceousmore » biomass allows for the utilization of the silage industry’s existing harvest, handling and storage infrastructure. A storage facility co-located with the algae production and conversion operations was designed to stabilize algal biomass produced in excess of conversion capacity during summer months for use in the winter when algal biomass production is reduced. Techno-economic assessment of the costs associated with ensiling algae and corn stover blends suggest it to be a cost effective approach, compared to drying. In a high algal biomass productivity scenario, costs of wet storage ($/gallon diesel) were only 65% of the cost of drying. When a reduced algal biomass productivity scenario was considered, the stored blend was able to cost-effectively provide sufficient biomass such that winter production in the algal ponds could cease, meanwhile incurring only 91% of the costs of drying; such an approach would facilitate algal biomass production in northern latitudes. Moreover, the wet storage approaches requiring only 8-10% of the total energy consumption and releasing only 20-25% of the greenhouse gasses when compared to a natural-gas based drying approach for microalgae stabilization.« less

Improved stability and oral bioavailability of Ganneng dropping pills following transforming lignans of herpetospermum caudigerum into nanosuspensions.

PubMed

Li, Juan-Juan; Cheng, Ling; Shen, Gang; Qiu, Ling; Shen, Cheng-Ying; Zheng, Juan; Xu, Rong; Yuan, Hai-Long

2018-01-01

The present study was designed to improve storage stability and oral bioavailability of Ganneng dropping pills (GNDP) by transforming lignans of Herpetospermum caudigerum (HL) composed of herpetrione (HPE) and herpetin (HPN) into nanosuspension (HL-NS), the main active ingredient of GNDP, HL-NS was prepared by high pressure homogenization and lyophilized to transform into solid nanoparticles (HL nanoparticles), and then the formulated HL nanoparticles were perfused into matrix to obtain NS-GNDP by melting method. For a period of 3 months, the content uniformity, storage stability and pharmacokinetics test in vivo of NS-GNDP were evaluated and compared with regular GNDP at room temperature. The results demonstrated that uniformity of dosage units of NS-GNDP was acceptable according to the criteria of Chinese Pharmacopoeia 2015J. Physical stability of NS-GNDP was investigated systemically using photon correlation spectroscopy (PCS), zeta potential measurement, and scanning electron microscopy (SEM). There was a slight increase in particles and PI of HL-NS re-dispersed from NS-GNDP after storage for 3 months, compared with new formulated NS-GNDP, which indicated a good redispersibility of the NS-GNDP containing HL-NS after storage. Besides, chemical stability of NS-GNDP was studied and the results revealed that HPE and HPN degradation was less when compared with that of GNDP, providing more than 99% of drug residue after storage for 3 months. In the dissolution test in vitro, NS-GNDP remarkably exhibited an increased dissolution velocity compared with GNDP and no distinct dissolution difference existed within 3 months. The pharmacokinetic study showed that HPE and HPN in NS-GNDP exhibited a significant increase in AUC 0-t , C max and decrease in T max when compared with regular GNDP. These results indicated that NS-GNDP possessed superiority with improved storage stability and increased dissolution rate and oral bioavailability. Copyright © 2018 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Evaluation of a high-moisture stabilization strategy for harvested microalgae blended with herbaceous biomass: Part I—Storage performance

DOE PAGES

Wendt, Lynn M.; Wahlen, Bradley D.; Li, Chenlin; ...

2017-06-01

Here, algal biomass is becoming increasingly attractive as a feedstock for biofuel production. However, the swing in algal biomass production between summer and winter months poses a challenge for delivering predictable, constant feedstock supply to a conversion facility. Drying is one approach for stabilizing algal biomass produced in excess during high productivity summer months for utilization during low productivity months, yet drying is energy intensive and thus costly. Wet, anaerobic storage, or ensiling, is a low-cost approach that is commonly used to preserve high moisture herbaceous feedstock. The potential for microalgae stabilization without the need for drying was investigated inmore » this study by simulating ensiling, in which oxygen limitation drives anaerobic fermentation of soluble sugars to organic acids, dropping the pH and thereby stabilizing the material. Algal biomass, Scenedesmus obliquus, was blended with corn stover and stored in acidic, anaerobic conditions at 60% moisture (wet basis) to simulate wet storage by means of ensiling. Results demonstrate that algae and corn stover blends were successfully preserved in anaerobic, acidic conditions for 30 days with < 2% dry matter loss occurring during storage compared to 21% loss in aerobic, non-acidified conditions. Likewise, Scenedesmus obliquus stored alone at 80% moisture (wet basis) in acidified, anaerobic conditions for 30 days, resulted in dry matter losses of 6–14%, compared to 44% loss in neutral pH, anaerobic storage and 37% loss in a neutral pH, aerobically stored condition. Additional experiments were performed at a larger scale in which an algae and corn stover blend was subject to mechanical oxygen exclusion and a Lactobacillus acidophilus inoculum, resulting in 8% loss over 35 days and further indicating that acidic, anaerobic conditions can stabilize microalgae biomass. In summary, the stabilization of harvested algae can be achieved through anaerobic storage, securing a feedstock that is labile yet of high value.« less

Evaluation of a high-moisture stabilization strategy for harvested microalgae blended with herbaceous biomass: Part I—Storage performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wendt, Lynn M.; Wahlen, Bradley D.; Li, Chenlin

Here, algal biomass is becoming increasingly attractive as a feedstock for biofuel production. However, the swing in algal biomass production between summer and winter months poses a challenge for delivering predictable, constant feedstock supply to a conversion facility. Drying is one approach for stabilizing algal biomass produced in excess during high productivity summer months for utilization during low productivity months, yet drying is energy intensive and thus costly. Wet, anaerobic storage, or ensiling, is a low-cost approach that is commonly used to preserve high moisture herbaceous feedstock. The potential for microalgae stabilization without the need for drying was investigated inmore » this study by simulating ensiling, in which oxygen limitation drives anaerobic fermentation of soluble sugars to organic acids, dropping the pH and thereby stabilizing the material. Algal biomass, Scenedesmus obliquus, was blended with corn stover and stored in acidic, anaerobic conditions at 60% moisture (wet basis) to simulate wet storage by means of ensiling. Results demonstrate that algae and corn stover blends were successfully preserved in anaerobic, acidic conditions for 30 days with < 2% dry matter loss occurring during storage compared to 21% loss in aerobic, non-acidified conditions. Likewise, Scenedesmus obliquus stored alone at 80% moisture (wet basis) in acidified, anaerobic conditions for 30 days, resulted in dry matter losses of 6–14%, compared to 44% loss in neutral pH, anaerobic storage and 37% loss in a neutral pH, aerobically stored condition. Additional experiments were performed at a larger scale in which an algae and corn stover blend was subject to mechanical oxygen exclusion and a Lactobacillus acidophilus inoculum, resulting in 8% loss over 35 days and further indicating that acidic, anaerobic conditions can stabilize microalgae biomass. In summary, the stabilization of harvested algae can be achieved through anaerobic storage, securing a feedstock that is labile yet of high value.« less

Fabrication of bismuth superhydrophobic surface on zinc substrate

NASA Astrophysics Data System (ADS)

Yu, Tianlong; Lu, Shixiang; Xu, Wenguo; He, Ge

2018-06-01

The dendritic Bi/Bi2O3/ZnO superhydrophobic surface (SHPS) was facilely obtained on zinc substrate via etching in 0.5 mol L-1 HCl solution for 2 min, immersing in 2 mmol L-1 Bi(NO3)3/0.1 mol L-1 HNO3 solution for 2.5 min and annealing treatment at 180 °C for 2 h. The wetting property results demonstrated that the superhydrophobic sample had excellent water-repellency with a static water contact angle of 160° and sliding angle of 0° under the optimum condition, which can be visually confirmed by the impacting droplet could rebound back immediately and roll off the horizontally placed sample. Moreover, it exhibited remarkable self-cleaning ability, buoyancy, desired stability in long-term storage in air, corrosion resistance in 3.5 wt% NaCl solution, ice-over delay at - 16 °C and durability in lab-simulated abrasion test.

Characteristics of aerobic granules grown on glucose and acetate in sequential aerobic sludge blanket reactors.

PubMed

Tay, J H; Liu, Q S; Liu, Y

2002-08-01

Aerobic granules were cultivated in two column-type sequential aerobic sludge blanket reactors fed with glucose and acetate, respectively. The characteristics of aerobic granules were investigated. Results indicated that the glucose- and acetate-fed granules have comparable characteristics in terms of settling velocity, size, shape, biomass density, hydrophobicity, physical strength, microbial activity and storage stability. Substrate component does not seem to be a key factor on the formation of aerobic granules. However, microbial diversity of the granules is closely associated with the carbon sources supplied to the reactors. Compared with the conventional activated sludge flocs, aerobic granules exhibit excellent physical characteristics that would be essential for industrial application. This research provides a complete set of characteristics data of aerobic granules grown on glucose and acetate, which would be useful for further development of aerobic granules-based compact bioreactor for handling high strength organic wastewater.

Activated carbon derived from melaleuca barks for outstanding high-rate supercapacitors

NASA Astrophysics Data System (ADS)

Luo, Qiu-Ping; Huang, Liang; Gao, Xiang; Cheng, Yongliang; Yao, Bin; Hu, Zhimi; Wan, Jun; Xiao, Xu; Zhou, Jun

2015-07-01

Activated carbon (AC) was prepared via carbonizing melaleuca bark in an argon atmosphere at 600 °C followed with KOH activation for high-rate supercapacitors. This AC electrode has a high capacitance of 233 F g-1 at a scan rate of 2 mV s-1 and an excellent rate capability of ˜80% when increasing the sweep rate from 2 to 500 mV s-1. The symmetric supercapacitor assembled by the above electrode can deliver a high energy density of 4.2 Wh kg-1 with a power density of 1500 W kg-1 when operated in the voltage range of 0-1 V in 1 M H2SO4 aqueous electrolyte while maintaining great cycling stability (less than 5% capacitance loss after 10 000 cycles at sweep rate of 100 mV s-1). All the outstanding electrochemical performances make this AC electrode a promising candidate for potential energy storage application.

Eco-friendly wood-based solid-state flexible supercapacitors from wood transverse section slice and reduced graphene oxide

NASA Astrophysics Data System (ADS)

Lv, Shaoyi; Fu, Feng; Wang, Siqun; Huang, Jingda; Hu, La

2015-07-01

An interesting wood-based all-solid-state supercapacitor is produced using reduced graphene oxide (RGO) coated on wood transverse section slice (WTSS) as electrode material by means of a low-cost, eco-friendly, and simple method for the first time. The RGO-coated WTSS electrode has a porous 3D honeycomb framework due to the hierarchical cellular structure of the WTSS substrate and can function as an electrolyte reservoir. This special construction endows this novel electrode with good areal capacitance (102 mF cm-2) and excellent cyclic stability (capacitance retention of 98.9% after 5000 cycles). In addition, the supercapacitors exhibit good mechanical flexibility and preserve almost constant capacitive behavior under different bending conditions. Our study introduces a new and eco-friendly material design for electrodes in future flexible energy storage devices that closely resemble natural materials. [Figure not available: see fulltext.

Soft and wrinkled carbon membranes derived from petals for flexible supercapacitors

PubMed Central

Yu, Xiuxiu; Wang, Ying; Li, Li; Li, Hongbian; Shang, Yuanyuan

2017-01-01

Biomass materials are promising precursors for the production of carbonaceous materials due to their abundance, low cost and renewability. Here, a freestanding wrinkled carbon membrane (WCM) electrode material for flexible supercapacitors (SCs) was obtained from flower petal. The carbon membrane was fabricated by a simple thermal pyrolysis process and further activated by heating the sample in air. As a binder and current collector-free electrode, the activated wrinkled carbon membrane (AWCM) exhibited a high specific capacitance of 332.7 F/g and excellent cycling performance with 92.3% capacitance retention over 10000 cycles. Moreover, a flexible all-solid supercapacitor with AWCM electrode was fabricated and showed a maximum specific capacitance of 154 F/g and great bending stability. The development of this flower petal based carbon membrane provides a promising cost-effective and environmental benign electrode material for flexible energy storage. PMID:28361914

Double-shell CuS nanocages as advanced supercapacitor electrode materials

NASA Astrophysics Data System (ADS)

Guo, Jinxue; Zhang, Xinqun; Sun, Yanfang; Zhang, Xiaohong; Tang, Lin; Zhang, Xiao

2017-07-01

Metal sulfides hollow structures are advanced materials for energy storage applications of lithium-ion batteries and supercapacitors. However, constructing hollow metal sulfides with specific features, such as multi-shell and non-spherical shape, still remains great challenge. In this work, we firstly demonstrate the synthesis of CuS double-shell hollow nanocages using Cu2O nanocubes as precursors. The synthesis processes involve the repeated anion exchange reaction with Na2S and the controllable etching using hydrochloric acid. The whole synthesis processes are well revealed and the obtained double-shell CuS is tested as pseudocapacitive electrode material for supercapacitors. As expected, the CuS double-shell hollow nanocages deliver high specific capacitance, good rate performance and excellent cycling stability due to their unique nano-architecture. The present work contributes greatly to the exploration of hollow metal sulfides with complex architecture and non-spherical shape, as well as their promising application in high-performance electrochemical supercapacitors.

Composite lithium metal anode by melt infusion of lithium into a 3D conducting scaffold with lithiophilic coating

PubMed Central

Liang, Zheng; Lin, Dingchang; Zhao, Jie; Lu, Zhenda; Liu, Yayuan; Liu, Chong; Lu, Yingying; Wang, Haotian; Yan, Kai; Tao, Xinyong; Cui, Yi

2016-01-01

Lithium metal-based battery is considered one of the best energy storage systems due to its high theoretical capacity and lowest anode potential of all. However, dendritic growth and virtually relative infinity volume change during long-term cycling often lead to severe safety hazards and catastrophic failure. Here, a stable lithium–scaffold composite electrode is developed by lithium melt infusion into a 3D porous carbon matrix with “lithiophilic” coating. Lithium is uniformly entrapped on the matrix surface and in the 3D structure. The resulting composite electrode possesses a high conductive surface area and excellent structural stability upon galvanostatic cycling. We showed stable cycling of this composite electrode with small Li plating/stripping overpotential (<90 mV) at a high current density of 3 mA/cm2 over 80 cycles. PMID:26929378

Chemically Bonded Phosphorus/Graphene Hybrid as a High Performance Anode for Sodium-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Jiangxuan; Yu, Zhaoxin; Gordin, Mikhail

2014-11-12

Room temperature sodium-ion batteries are of great interest for high-energy-density energy storage systems because of low-cost, natural abundance of sodium. Here, we report a novel graphene nanosheets-wrapped phosphorus composite as an anode for high performance sodium-ion batteries though a facile ball-milling of red phosphorus and graphene nanosheets. Not only can the graphene nanosheets significantly improve the electrical conductivity, but they also serve as a buffer layer to accommodate the large volume change of phosphorus in the charge-discharge process. As a result, the graphene wrapped phosphorus composite anode delivers a high reversible capacity of 2077 mAh/g with excellent cycling stability (1700more » mAh/g after 60 cycles) and high Coulombic efficiency (>98%). This simple synthesis approach and unique nanostructure can potentially extend to other electrode materials with unstable solid electrolyte interphases in sodium-ion batteries.« less

A hydrothermally synthesized LiFePO4/C composite with superior low-temperature performance and cycle life

NASA Astrophysics Data System (ADS)

Wu, Guan; Liu, Na; Gao, Xuguang; Tian, Xiaohui; Zhu, Yanbin; Zhou, Yingke; Zhu, Qingyou

2018-03-01

The LiFePO4/C composites have been successfully synthesized by a hydrothermal process, with the combined carbon sources of fructose and calcium lignosulfonate. The morphology and microstructure of LiFePO4/C were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The electrochemical properties were evaluated by the constant-current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The uniform carbon coating layer derived from calcium lignosulfonate can effectively improve the electronic conductivity, lithium-ion diffusivity and surface stability of the LiFePO4/C composites and prevent the side reactions between the LiFePO4 particles and electrolytes. The LiFePO4/C composites display excellent rate capability, superior cycle life and outstanding low temperature performance, which are promising for lithium-ion battery applications in electrical vehicles and electrical energy storage systems.

Novel synthesis of Ni-ferrite (NiFe{sub 2}O{sub 4}) electrode material for supercapacitor applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Venkatachalam, V.; Jayavel, R., E-mail: rjvel@annauniv.edu

Novel nanocrystalline NiFe{sub 2}O{sub 4} has been synthesized through combustion route using citric acid as a fuel. Phase of the synthesized material was analyzed using powder X-ray diffraction. The XRD study revealed the formation of spinel phase cubic NiFe{sub 2}O{sub 4} with high crystallinity. The average crystallite size of NiFe{sub 2}O{sub 4} nanomaterial was calculated from scherrer equation. The electrochemical properties were realized by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. The electrode material shows a maximum specific capacitance of 454 F/g with pseudocapacitive behavior. High capacitance retention of electrode material over 1000 continuous charging-discharging cycles suggests its excellent electrochemicalmore » stability. The results revealed that the nickel ferrite electrode is a potential candidate for energy storage applications in supercapacitor.« less

Monolithically Integrated Self-Charging Power Pack Consisting of a Silicon Nanowire Array/Conductive Polymer Hybrid Solar Cell and a Laser-Scribed Graphene Supercapacitor.

PubMed

Liu, Hanhui; Li, Mengping; Kaner, Richard B; Chen, Songyan; Pei, Qibing

2018-05-09

Owing to the need for portable and sustainable energy sources and the development trend for microminiaturization and multifunctionalization in the electronic components, the study of integrated self-charging power packs has attracted increasing attention. A new self-charging power pack consisting of a silicon nanowire array/poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) hybrid solar cell and a laser-scribed graphene (LSG) supercapacitor has been fabricated. The Si nanowire array/PEDOT:PSS hybrid solar cell structure exhibited a high power conversion efficiency (PCE) of 12.37%. The LSG demonstrated excellent energy storage capability for the power pack, with high current density, energy density, and cyclic stability when compared to other supercapacitor electrodes such as active carbon and conducting polymers. The overall efficiency of the power unit is 2.92%.

Fabricating Ir/C Nanofiber Networks as Free-Standing Air Cathodes for Rechargeable Li-CO2 Batteries.

PubMed

Wang, Chengyi; Zhang, Qinming; Zhang, Xin; Wang, Xin-Gai; Xie, Zhaojun; Zhou, Zhen

2018-06-07

Li-CO 2 batteries are promising energy storage systems by utilizing CO 2 at the same time, though there are still some critical barriers before its practical applications such as high charging overpotential and poor cycling stability. In this work, iridium/carbon nanofibers (Ir/CNFs) are prepared via electrospinning and subsequent heat treatment, and are used as cathode catalysts for rechargeable Li-CO 2 batteries. Benefitting from the unique porous network structure and the high activity of ultrasmall Ir nanoparticles, Ir/CNFs exhibit excellent CO 2 reduction and evolution activities. The Li-CO 2 batteries present extremely large discharge capacity, high coulombic efficiency, and long cycling life. Moreover, free-standing Ir/CNF films are used directly as air cathodes to assemble Li-CO 2 batteries, which show high energy density and ultralong operation time, demonstrating great potential for practical applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A universal cooperative assembly-directed method for coating of mesoporous TiO2 nanoshells with enhanced lithium storage properties

PubMed Central

Guan, Bu Yuan; Yu, Le; Li, Ju; Lou, Xiong Wen (David)

2016-01-01

TiO2 is exceptionally useful, but it remains a great challenge to develop a universal method to coat TiO2 nanoshells on different functional materials. We report a one-pot, low-temperature, and facile method that can rapidly form mesoporous TiO2 shells on various inorganic, organic, and inorganic-organic composite materials, including silica-based, metal, metal oxide, organic polymer, carbon-based, and metal-organic framework nanomaterials via a cooperative assembly-directed strategy. In constructing hollow, core-shell, and yolk-shell geometries, both amorphous and crystalline TiO2 nanoshells are demonstrated with excellent control. When used as electrode materials for lithium ion batteries, these crystalline TiO2 nanoshells composed of very small nanocrystals exhibit remarkably long-term cycling stability over 1000 cycles. The electrochemical properties demonstrate that these TiO2 nanoshells are promising anode materials. PMID:26973879

Facile Preparation of Porous WO3 Film for Photoelectrochemical Splitting of Natural Seawater

NASA Astrophysics Data System (ADS)

Shi, Yonghong; Li, Yuangang; Wei, Xiaoliang; Feng, Juan; Li, Huajing; Zhou, Wanyi

2017-12-01

Sunlight-driven natural seawater splitting provides a promising way for large-scale conversion and storage of solar energy. Here, we develop a facile and low-cost method via a deposition-annealing technique to fabricate porous WO3 film and demonstrate its application as a photoanode for natural seawater splitting. The WO3 film yields a photocurrent density of 1.95 mA cm-2 and possesses excellent stability at 1.23 V (versus RHE), under the illumination of 100 mW cm-2 (AM 1.5G). The photoelectrochemical performance is ascribed to the large surface area and good permeation of the electrolyte into the porous film. Furthermore, the photocurrent density remains almost the same during 3 h continuous light irradiation. The evolution of chlorine gas from seawater splitting was determined with qualitative and quantitative analyses, with a Faradic efficiency of about 56%.

Feather like highly active Co3O4 electrode for supercapacitor application: a potentiodynamic approach

NASA Astrophysics Data System (ADS)

Niveditha, C. V.; Aswini, R.; Jabeen Fatima, M. J.; Ramanarayan, Rajita; Pullanjiyot, Nijisha; Swaminathan, Sindhu

2018-06-01

This investigation focuses on the in situ preparation of cobalt oxide through a less explored potentiodynamic approach under ambient conditions. A spinel structured feather like p-type cobalt oxide is obtained having dual bandgaps. Gracing Incidence x-ray Diffraction, Raman spectroscopy, UV-Visble spectroscopy, Scanning Electron Microscope and Hall measurement are used to study the structural, optical, morphological and electrical characteristics of the film. The prepared film showed an excellent cyclic stability upto 1600 number of cycles and good charge retention as obtained from cyclic voltammetry and galvanostatic charge-discharge measurements. A high specific capacitance of 396.67 F g‑1, specific energy 71.40 Wh kg‑1 and specific power 10.02 kW kg‑1 is obtained, implying supercapacitive nature of the material. Overall a sustainable energy storage material, prepared by template free potentiodynamic method for new generation devices has been explored in this work.

Hierarchical silicon nanowires-carbon textiles matrix as a binder-free anode for high-performance advanced lithium-ion batteries

PubMed Central

Liu, Bin; Wang, Xianfu; Chen, Haitian; Wang, Zhuoran; Chen, Di; Cheng, Yi-Bing; Zhou, Chongwu; Shen, Guozhen

2013-01-01

Toward the increasing demands of portable energy storage and electric vehicle applications, the widely used graphite anodes with significant drawbacks become more and more unsuitable. Herein, we report a novel scaffold of hierarchical silicon nanowires-carbon textiles anodes fabricated via a facile method. Further, complete lithium-ion batteries based on Si and commercial LiCoO2 materials were assembled to investigate their corresponding across-the-aboard performances, demonstrating their enhanced specific capacity (2950 mAh g−1 at 0.2 C), good repeatability/rate capability (even >900 mAh g−1 at high rate of 5 C), long cycling life, and excellent stability in various external conditions (curvature, temperature, and humidity). Above results light the way to principally replacing graphite anodes with silicon-based electrodes which was confirmed to have better comprehensive performances. PMID:23572030

Template-Free Synthesis of Hollow-Structured Co 3 O 4 Nanoparticles as High-Performance Anodes for Lithium-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Deli; Yu, Yingchao; He, Huan

2015-02-24

We have developed a template-free procedure to synthesize Co3O4 hollow-structured nanoparticles on a Vulcan XC-72 carbon support. The material was synthesized via an impregnation–reduction method followed by air oxidation. In contrast to spherical particles, the hollow-structured Co3O4 nanoparticles exhibited excellent lithium storage capacity, rate capability, and cycling stability when used as the anode material in lithium-ion batteries. Electrochemical testing showed that the hollow-structured Co3O4 particles delivered a stable reversible capacity of about 880 mAh/g (near the theoretical capacity of 890 mAh/g) at a current density of 50 mA/g after 50 cycles. The superior electrochemical performance is attributed to its uniquemore » hollow structure, which combines nano- and microscale properties that facilitate electron transfer and enhance structural robustness.« less

Amorphous and Metastable Microcrystalline Rapidly Solidified Alloys: Status and Potential.

DTIC Science & Technology

1980-05-01

stability. 9. More effective quenching techniques should be studied, to produce thicker amorphous tapes for magnetic applications. 10. The production of bulk ...for some metallic glasses * excellent magnetic properties for metallic glasses * high strength, toughness and excellent fatigue and crack growth...Forming 65 Chapter 8 - PROPERTIES OF METALLIC GLASSES 69 Magnetic Properties 69 Electrical Properties 81 Mechanical Properties 83 Radiation Stability 101

The stability of water- and fat-soluble vitamin in dentifrices according to pH level and storage type.

PubMed

Park, Jung-Eun; Kim, Ki-Eun; Choi, Yong-Jun; Park, Yong-Duk; Kwon, Ha-Jeong

2016-02-01

The purpose of this study is to evaluate the vitamin stabilities in dentifrices by analyzing various vitamins according to the level and storage temperature. The stabilities of water- and fat-soluble vitamins were investigated in buffer solution at different pH values (4, 7, 8, 10 and 11) for 14 days and in dentifrices at different pH (7 and 10) for 5 months at two temperature conditions (room and refrigeration temperature) by analyzing the remaining amounts using HPLC methods. In the buffer solution, the stability of vitamins B1 , B6 and C was increased as the pH values increased. Vitamins E and K showed poor stability at pH 4, and vitamin B3 showed poor stability at pH 11. In dentifrices, the storage temperature highly influenced vitamin stability, especially vitamins C and E, but the stabilities of vitamins B1 and C according to pH values did not correspond to the buffer solution tests. Vitamin B group was relatively stable in dentifrices, but vitamin C completely disappeared after 5 months. Vitamin K showed the least initial preservation rates. Vitamins were not detected in commercial dentifrices for adults and detected amounts were less than the advertised contents in dentifrices for children. Copyright © 2015 John Wiley & Sons, Ltd.

Aggregates of octenylsuccinate oat β-glucan as novel capsules to stabilize curcumin over food processing, storage and digestive fluids and to enhance its bioavailability.

PubMed

Liu, J; Lei, L; Ye, F; Zhou, Y; Younis, Heba G R; Zhao, G

2018-01-24

Self-aggregates of octenylsuccinate oat β-glucan (A OSG ) have been verified as nanocapsules to load curcumin, a representative of hydrophobic phytochemicals. This study primarily investigated the stability of curcumin-loaded A OSG s over food processing, storage and digestive fluids. Curcumin in A OSG s showed better stability over storage and thermal treatment than its free form. Curcumin loaded in A OSGs stored at 4 °C in the dark exhibited higher stability than that at higher temperatures or exposed to light. Approximately 18% of curcumin was lost after five freeze-thaw cycles. Curcumin in A OSG was more stable than its free form in mimetic intestinal fluids, attesting to the effective protection of A OSG for curcumin over digestive environments. When curcumin-loaded A OSG travelled across mimetic gastric and intestinal fluids, curcumin was tightly accommodated in the capsule, while it rapidly escaped as the capsule reached the colon. Interestingly, the curcumin loaded in A OSG generated higher values of C max and area under the curve than did its free counterpart. These observations showed that A OSG is a powerful vehicle for stabilizing hydrophobic phytochemicals in food processing and storage, facilitating their colon-targeted delivery and enhancing their bioavailability.

Physical and chemical stability of pemetrexed in infusion solutions.

PubMed

Zhang, Yanping; Trissel, Lawrence A

2006-06-01

Pemetrexed is a multitargeted, antifolate, antineoplastic agent that is indicated for single-agent use in locally advanced or metastatic non-small-cell lung cancer after prior chemotherapy and in combination with cisplatin for the treatment of malignant pleural mesothelioma not treatable by surgery. Currently, there is no information on the long-term stability of pemetrexed beyond 24 hours. To evaluate the longer-term physical and chemical stability of pemetrexed 2, 10, and 20 mg/mL in polyvinyl chloride (PVC) bags of dextrose 5% injection and NaCl 0.9% injection. Triplicate samples of pemetrexed were prepared in the concentrations and infusion solutions required. Evaluations for physical and chemical stability were performed initially and over 2 days at 23 degrees C protected from light and exposed to fluorescent light, and over 31 days of storage at 4 degrees C protected from light. Physical stability was assessed using turbidimetric and particulate measurement as well as visual observation. Chemical stability was evaluated by HPLC. All pemetrexed solutions remained chemically stable, with little or no loss of pemetrexed over 2 days at 23 degrees C, protected from light and exposed to fluorescent light, and over 31 days of storage at 4 degrees C, protected from light. The room temperature samples were physically stable throughout the 48 hour test period. However, pemetrexed admixtures developed large numbers of microparticulates during refrigerated storage exceeding 24 hours. Pemetrexed is chemically stable for 2 days at room temperature and 31 days refrigerated in dextrose 5% injection and NaCl 0.9% injection. However, substantial numbers of microparticulates may form in pemetrexed diluted in the infusion solutions in PVC bags, especially during longer periods of refrigerated storage. Limiting the refrigerated storage period to the manufacturer-recommended 24 hours will limit particulate formation.

Water cavities of sH clathrate hydrate stabilized by molecular hydrogen.

PubMed

Strobel, Timothy A; Koh, Carolyn A; Sloan, E Dendy

2008-02-21

X-ray diffraction and Raman spectroscopic measurements confirm that molecular hydrogen can be contained within the small water cavities of a binary sH clathrate hydrate using large guest molecules that stabilize the large cavity. The potential increase in hydrogen storage could be more than 40% when compared with binary sII hydrates. This work demonstrates the stabilization of hydrogen in a hydrate structure previously unknown for encapsulating molecular hydrogen, indicating the potential for other inclusion compound materials with even greater hydrogen storage capabilities.

The role of silica nanoparticles on long-term room-temperature stabilization of water-in-oil emulsions containing microalgae.

PubMed

Fernández, L; Scher, H; VanderGheynst, J S

2015-12-01

Prior research has demonstrated that microalgae can be stored for extended periods of time at room temperature in water-in-oil (W/O) emulsions stabilized by surface modified silica nanoparticles. However, little research has been done to examine the impact of nanoparticle concentration on emulsion stability. Such information is important for large-scale production of emulsions for microalgae storage and delivery. Studies were done to examine the impact of silica nanoparticle concentration on emulsion stability and identify the lower limit for nanoparticle concentration. Emulsion physical stability was determined using internal phase droplet size measurements and biological stability was evaluated using cell density measurements. The results demonstrate that nanoparticle concentrations as low as 0·5wt% in the oil phase can be used without significant losses in emulsion stability and microalgae viability. Stabilization technologies are needed for long-term storage and application of microalgae in agricultural-scale systems. While prior work has demonstrated that water-in-oil emulsions containing silica nanoparticles offer a promising solution for long-term microalgae storage at room temperature, little research has been done to examine the impact of nanoparticle concentration on emulsion stability. Here, we show the effects of silica nanoparticle concentration on maintaining physical stability of emulsions and sustaining viable cells. The results enable informed decisions to be made regarding production of emulsions containing silica nanoparticles and associated impacts on stabilization of microalgae. © 2015 The Society for Applied Microbiology.

Temperature stability of Poly-[hemoglobin-superoxide dismutase-catalase-carbonic anhydrase] in the form of a solution or in the lyophilized form during storage at -80 °C, 4 °C, 25 °C and 37 °C or pasteurization at 70 °C.

PubMed

Bian, Y Z; Guo, C; Chang, T M S

2016-01-01

Polyhemoglobin-superoxide dismutase-catalase-carbonic anhydrase (Poly-[Hb-SOD-CAT-CA]) contains all three major functions of red blood cells (RBCs) at an enhanced level. It transports oxygen, removes oxygen radicals and transports carbon dioxide. Our previous studies in a 90-min 30 mm Hg Mean Arterial Pressure (MAP) sustained hemorrhagic shock rat model shows that it is more effective than blood in the lowering of elevated intracellular pCO2, recovery of ST-elevation and histology of the heart and intestine. This paper is to analyze the storage and temperature stability. Allowable storage time for RBC is about 1 d at room temperature and 42 d at 4 °C. Also, RBC cannot be pasteurized to remove infective agents like HIV and Ebola. PolyHb can be heat sterilized and can be stored for 1 year even at room temperature. However, Poly-[Hb-SOD-CAT-CA] contains both Hb and enzymes and enzymes are particularly sensitive to storage and heat. We thus carried out studies to analyze its storage stability at different temperatures and heat pasteurization stability. Results of storage stability show that lyophilization extends the storage time to 1 year at 4 °C and 40 d at room temperature (compared to respectively, 42 d and 1 d for RBC). After the freeze-dry process, the enzyme activities of Poly-[SFHb-SOD-CAT-CA] was 100 ± 2% for CA, 100 ± 2% for SOD and 93 ± 3.5% for CAT. After heat pasteurization at 70 °C for 2 h, lyophilized Poly-[Hb-SOD-CAT-CA] retained good enzyme activities of CA 97 ± 4%, SOD 100 ± 2.5% and CAT 63.8 ± 4%. More CAT can be added during the crosslinking process to maintain the same enzyme ratio after heat pasteurization. Heat pasteurization is possible only for the lyophilized form of Poly-[Hb-SOD-CAT-CA] and not for the solution. It can be easily reconstituted by dissolving in suitable solutions that continues to have good storage stability though less than that for the lyophilized form. According to the P50 value, Poly-[SFHb-SOD-CAT-CA] retains its oxygen carrying ability before and after long-term storage.

Fluidized-Bed Drying and Storage Stability of Cryptococcus flavescens OH 182.9, a Biocontrol Agent of Fusarium Head Blight

USDA-ARS?s Scientific Manuscript database

A method to produce dried granules of Cryptococcus flavescens (formerly Cryptococcus nodaensis) OH 182.9 was developed and the granules evaluated for storage stability. Small spherical granules were produced and dried using a fluidized bed dryer. A drying and survival curve was produced for the pr...

[Immobilization of pectawamorine G10x by gel entrapment].

PubMed

Bogatskiĭ, A V; Davidenko, T I; Areshidze, I V; Gren', T A; Sevast'ianov, O V

1979-01-01

Polyacrylamide gel immobilization of pectawamorine G10x was investigated. Its pectinesterase and polygalacturonase activity and stability in storage were measured. The degree of pectawamorine binding during gel immobilization was 80--90%, 55% of initial activity being retained. Thermal stability of the immobilized and native preparations was equal. Pectinesterase activity of the gel immobilized enzyme increased during storage.

Storage stability of biodegradable polyethylene glycol microspheres

NASA Astrophysics Data System (ADS)

Jain, Era; Sheth, Saahil; Polito, Kristen; Sell, Scott A.; Zustiak, Silviya P.

2017-10-01

Degradable hydrogel microspheres are popular choices for multiple biomedical applications, including drug, protein, or cell carriers for minimally invasive delivery. Clinical transitioning of such new, sensitive pharmaceutical preparations requires investigation of storage methods that retain key properties for extended time. In this study, we sought to determine the influence of seven common storage conditions on the physical and mechanical properties of degradable polyethylene glycol (PEG) hydrogel microspheres: 25 °C, 4 °C, -80 °C, lyophilization/-20 °C, dimethyl sulfoxide/-80 °C, dimethyl sulfoxide/lyophilization/-20 °C, vacuum/-20 °C. We have outlined the storage conditions in detail and explained their effect on swelling ratio, stiffness and degradation rate post-storage. Additionally, we have implemented protein-loaded hydrogels to evaluate the effect of storage conditions on diffusivity as well as protein stability post-storage. We found that hydrogels could be stored short-term (1-4 d) under moist conditions (i.e. storage without drying) without a substantial loss of properties. For extended storage (7-28 d), they could be stored either at  -80 °C (moist condition) or vacuum drying (dry condition).

Flavor and chiral stability of lemon-flavored hard tea during storage.

PubMed

He, Fei; Qian, YanPing L; Qian, Michael C

2018-01-15

Flavor stability of hard tea beverage was investigated over eight weeks of storage. The volatile compounds were analyzed using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and two-dimensional GC-MS. Quantitative analysis showed that the concentrations of linalool, citronellol, geranial, neral, geraniol, and nerol decreased dramatically during storage, whereas α-terpineol showed an increasing trend during storage. Heart-cut two-dimensional GC-MS (2D-GC-MS) chirality analysis showed that (R)-(+)-limonene, (R)-(-)-linalool, (S)-(-)-α-terpineol and (S)-(-)-4-terpineol dominated in the fresh hard tea samples, however, the configuration changed during storage for the terpene alcohols. The storage conditions did not change the configuration of limonene. A conversion of (R)-(-)-linalool to (S)-(+) form was observed during storage. Both (S)-α-terpineol and (S)-4-terpineol dominated at beginning of the storage, but (R)-(+)-α-terpineol became dominated after storage, suggested in addition to isomerization from (S)-α-terpineol, other precursors could also generate α-terpineol with (R)-isomer preference. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fabrication of a 3D Hierarchical Sandwich Co9 S8 /α-MnS@N-C@MoS2 Nanowire Architectures as Advanced Electrode Material for High Performance Hybrid Supercapacitors.

PubMed

Kandula, Syam; Shrestha, Khem Raj; Kim, Nam Hoon; Lee, Joong Hee

2018-06-01

Supercapacitors suffer from lack of energy density and impulse the energy density limit, so a new class of hybrid electrode materials with promising architectures is strongly desirable. Here, the rational design of a 3D hierarchical sandwich Co 9 S 8 /α-MnS@N-C@MoS 2 nanowire architecture is achieved during the hydrothermal sulphurization reaction by the conversion of binary mesoporous metal oxide core to corresponding individual metal sulphides core along with the formation of outer metal sulphide shell at the same time. Benefiting from the 3D hierarchical sandwich architecture, Co 9 S 8 /α-MnS@N-C@MoS 2 electrode exhibits enhanced electrochemical performance with high specific capacity/capacitance of 306 mA h g -1 /1938 F g -1 at 1 A g -1 , and excellent cycling stability with a specific capacity retention of 86.9% after 10 000 cycles at 10 A g -1 . Moreover, the fabricated asymmetric supercapacitor device using Co 9 S 8 /α-MnS@N-C@MoS 2 as the positive electrode and nitrogen doped graphene as the negative electrode demonstrates high energy density of 64.2 Wh kg -1 at 729.2 W kg -1 , and a promising energy density of 23.5 Wh kg -1 is still attained at a high power density of 11 300 W kg -1 . The hybrid electrode with 3D hierarchical sandwich architecture promotes enhanced energy density with excellent cyclic stability for energy storage. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

All-solid-state asymmetric supercapacitors based on Fe-doped mesoporous Co3O4 and three-dimensional reduced graphene oxide electrodes with high energy and power densities.

PubMed

Zhang, Cheng; Wei, Jun; Chen, Leiyi; Tang, Shaolong; Deng, Mingsen; Du, Youwei

2017-10-19

An asymmetric supercapacitor offers opportunities to effectively utilize the full potential of the different potential windows of the two electrodes for a higher operating voltage, resulting in an enhanced specific capacitance and significantly improved energy without sacrificing the power delivery and cycle life. To achieve high energy and power densities, we have synthesized an all-solid-state asymmetric supercapacitor with a wider voltage range using Fe-doped Co 3 O 4 and three-dimensional reduced graphene oxide (3DrGO) as the positive and negative electrodes, respectively. In contrast to undoped Co 3 O 4 , the increased density of states and modified charge spatial separation endow the Fe-doped Co 3 O 4 electrode with greatly improved electrochemical capacitive performance, including high specific capacitance (1997 F g -1 and 1757 F g -1 at current densities of 1 and 20 A g -1 , respectively), excellent rate capability, and superior cycling stability. Remarkably, the optimized all-solid-state asymmetric supercapacitor can be cycled reversibly in a wide range of 0-1.8 V, thus delivering a high energy density (270.3 W h kg -1 ), high power density (9.0 kW kg -1 at 224.2 W h kg -1 ), and excellent cycling stability (91.8% capacitance retention after 10 000 charge-discharge cycles at a constant current density of 10 A g -1 ). The superior capacitive performance suggests that such an all-solid-state asymmetric supercapacitor shows great potential for developing energy storage systems with high levels of energy and power delivery.

Formulation and Stabilization of Francisella tularensis Live Vaccine Strain

PubMed Central

OHTAKE, SATOSHI; MARTIN, RUSSELL A.; SAXENA, ATUL; LECHUGA-BALLESTEROS, DAVID; SANTIAGO, ARACELI E; BARRY, EILEEN M.; TRUONG-LE, VU

2012-01-01

Francisella tularensis live vaccine strain (F. tularensis LVS), a promising vaccine candidate for protection against F. tularensis exposure, is a particularly thermolabile vaccine and difficult to stabilize sufficiently for storage under refrigerated conditions. Our preliminary data show that F. tularensis LVS can be stabilized in the dried state using foam drying, a modified freeze drying method, with sugar-based formulations. The process was conducted under mild drying conditions, which resulted in a good titer retention following processing. The inclusion of osmolytes in the growth media resulted in an acceleration of growth kinetics, although no change in osmotolerance was observed. The optimized F. tularensis formulation, which contained trehalose, gelatin, and Pluronic F68 demonstrated stability for approximately 1.5 weeks at 37°C (i.e., time required for the vaccine to decrease in potency by 1 log10 colony forming unit) and for 12 weeks at 25°C. At refrigerator storage condition (4°C), stabilized F. tularensis LVS vaccine exhibited no activity loss for at least 12 weeks. This stabilization method utilizes conventional freeze dryers and pharmaceutically approved stabilizers, and thus can be readily implemented at many manufacturing sites for large-scale production of stabilized vaccines. The improved heat stability of the F. tularensis LVS could mitigate risks of vaccine potency loss during long-term storage, shipping, and distribution. PMID:21491457

Effect of processing and storage on the stability of flaxseed lignan added to bakery products.

PubMed

Hyvärinen, Helena K; Pihlava, Juha-Matti; Hiidenhovi, Jaakko A; Hietaniemi, Veli; Korhonen, Hannu J T; Ryhänen, Eeva-Liisa

2006-01-11

The study focused on the effects of processing and storage on the stability of flaxseed-derived secoisolariciresinol diglucoside (SDG) added to various bakery products. The SDG concentration of doughs, baked rye breads, graham buns, and muffins was analyzed by high-performance liquid chromatography-diode array detection; the baked products were analyzed immediately after baking and upon storage at room temperature for 1 week and at -25 degrees C for 1 and 2 months, respectively. Added SDG was found to withstand normal baking temperatures in all bakery products. SDG also was a relatively stable compound during storage. Similarly, the content of SDG in flax buns containing fat-free flaxseed meal was unaffected by storage. We conclude that cereal-based bakery products can be supplemented with flaxseed-derived SDG.

Influence of storage conditions on the stability of monomeric anthocyanins studied by reversed-phase high-performance liquid chromatography.

PubMed

Morais, Helena; Ramos, Cristina; Forgács, Esther; Cserháti, Tibor; Oliviera, José

2002-04-25

The effect of light, storage time and temperature on the decomposition rate of monomeric anthocyanin pigments extracted from skins of grape (Vitis vinifera var. Red globe) was determined by reversed-phase high-performance liquid chromatography (RP-HPLC). The impact of various storage conditions on the pigment stability was assessed by stepwise regression analysis. RP-HPLC separated well the five anthocyanins identified and proved the presence of other unidentified pigments at lower concentrations. Stepwise regression analysis confirmed that the overall decomposition rate of monomeric anthocyanins, peonidin-3-glucoside and malvidin-3-glucoside significantly depended on the time and temperature of storage, the effect of storage time being the most important. The presence or absence of light exerted a negligible impact on the decomposition rate.

Pilot scale treatment of chromite ore processing residue using sodium sulfide in single reduction and coupled reduction/stabilization processes.

PubMed

Velasco, Antonio; Ramírez, Martha; Hernández, Sergio; Schmidt, Winfried; Revah, Sergio

2012-03-15

Single Cr(VI) reduction and coupled reduction/stabilization (R/S) processes were evaluated at pilot scale to determine their effectiveness to treat chromite ore processing residue (COPR). Sodium sulfide was used as the reducing agent and cement, gypsum and lime were tested as the stabilizing agents. The pilot experiments were performed in a helical ribbon blender mixer with batches of 250 kg of COPR and mixing time up to 30 min. Na2S/Cr(VI) mass ratios of 4.6, 5.7 and 6.8 were evaluated in the single reduction process to treat COPR with Cr(VI) concentration of ≈4.2 g/kg. The R/S process was tested with a Na2S/Cr(VI) mass ratio of 5.7 and including stabilizing agents not exceeding 5% (w/w(COPR)), to treat COPR with a Cr(VI) content of ≈5.1g/kg. The single reduction process with a ratio of 6.8, reached Cr(VI) reduction efficiencies up to 97.6% in the first days, however these values decreased to around 93% after 380 days of storage. At this point the total Cr level was around 12.5 mg/L. Cr(VI) removal efficiencies exceeding 96.5% were reached and maintained during 380 days when the coupled R/S process was evaluated. Total Cr levels lower than 5 mg/l were attained at the initials days in all R/S batch tested, however after 380 days, concentrations below the regulatory limit were only found with gypsum (2%) as single agent and with a blend of cement (4%) and lime (1%). These results indicated that the coupled R/S process is an excellent alternative to stabilize COPR. Copyright © 2011 Elsevier B.V. All rights reserved.

One-pot synthesis of CoNiO2 single-crystalline nanoparticles as high-performance electrode materials of asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Du, Weimin; Gao, Yanping; Tian, Qingqing; Li, Dan; Zhang, Zhenhu; Guo, Jiaojiao; Qian, Xuefeng

2015-09-01

A facile one-pot solvothermal method has been developed to synthesize CoNiO2 single-crystalline nanoparticles. Crystal phase, morphology, crystal lattice, and composition of the obtained products were characterized by X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, and energy-dispersive X-ray analysis, respectively. Results revealed that the as-synthesized CoNiO2 nanoparticles belong to cubic structure with narrow size-distribution (8-10 nm). Subsequently, new asymmetric supercapacitors were successfully assembled with CoNiO2 nanoparticles as positive electrode and activated carbon as negative electrode. The electrochemical results show that asymmetric supercapacitors based on CoNiO2 nanoparticles possess excellent supercapacitor properties, i.e., a stable electrochemical window of 0-1.7 V, higher energy density of 24.0 Wh/kg at a power density of 415.4 W/kg, and excellent cycling stability (96.8 % capacitance retention after 5000 charge-discharge cycles). Meanwhile, both a light-emitting diode and a mini fan can be powered by two series connection asymmetric supercapacitors. These results imply that the present asymmetric supercapacitors based on CoNiO2 nanoparticles possess the promising potential application in the field of high-performance energy storage.

Nitrogen-doped two-dimensional porous carbon sheets derived from clover biomass for high performance supercapacitors

NASA Astrophysics Data System (ADS)

Wang, Cunjing; Wu, Dapeng; Wang, Hongju; Gao, Zhiyong; Xu, Fang; Jiang, Kai

2017-09-01

Highly porous carbon sheets were prepared from fresh clover stems under air atmosphere via a facile potassium chloride salt-sealing technique, which not only avoids using the high cost inert gas protection but also spontaneously introduce multi-level porosity into the carbon structure taking advantage of the trace of oxygen in the molten salt system. The as-obtained porous carbon sheets possess high specific surface area of 2244 m2 g-1 and interconnected hierarchical pore structures from micro-to macro-scale, which provide abundant storage active sites and fast ion diffusion channels. In addition, the spontaneously formed N (2.55 at%) and O (6.94 at%) doping sites not only improve the electron conductivity of the electrode but also enhance the specific capacitance by introducing pseudocapacitance. When employed as supercapacitor electrodes, a high specific capacitance of 436 F g-1 at 1 A g-1 and an excellent rate capacity with capacitance remaining 290 F g-1 at 50 A g-1 are demonstrated. Furthermore, the assembled symmetric supercapacitor delivers a high specific capacitance of 420 F g-1 at 0.5 A g-1, excellent energy density of 58.4 Wh kg-1 and good cycling stability which retains 99.4% of the initial capacitance at 5 A g-1 after 30,000 cycles.

Simultaneously achieve soluble expression and biomimetic immobilization of Candida antarctica lipase B by introducing polyamine tags.

PubMed

Zhou, Xiaoxue; Han, Yu; Lv, Zheng; Tian, Xuemei; Li, Han; Xie, Panpan; Zheng, Liangyu

2017-05-10

Polyamine tags fused in Candida antarctica lipase B (CalB) can help achieve high soluble expression of CalB in E. coli and can directly mediate silicification, which leads to rapid formation of a CalB-silica particle complex through a one-step approach. After optimization experiments, the fused lipase CalB tagged with 6-histidine at the N terminal and 10-lysine at the C terminal (6His-CalB-10Lys) is effectively expressed with high solubility (0.1mg/mL) and specific activity (10.1U/mg), and easily cross-linked in silica particles with a high immobilization efficiency of 96.8% and activity recovery of 81.5%. The immobilized lipase 6His-CalB-10Lys exhibits excellent performance at broad temperature ranges, high thermal and storage stabilities, and superior reusability. Michaelis-Menten kinetics indicates that the affinity and enantioselectivity of the free and immobilized 6His-CalB-10Lys toward the substrate are better than that of commercial Novozym 435 in enantioselective resolution of (S)-N-(2-ethyl-6-methylphenyl) alanine ((S)-NEMPA). The strategies described in this paper are useful for the facile expression and construction of diverse enzyme systems with high efficiency and excellent recyclability. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrathin Carbon with Interspersed Graphene/Fullerene-like Nanostructures: A Durable Protective Overcoat for High Density Magnetic Storage.

PubMed

Dwivedi, Neeraj; Satyanarayana, Nalam; Yeo, Reuben J; Xu, Hai; Ping Loh, Kian; Tripathy, Sudhiranjan; Bhatia, Charanjit S

2015-06-25

One of the key issues for future hard disk drive technology is to design and develop ultrathin (<2 nm) overcoats with excellent wear- and corrosion protection and high thermal stability. Forming carbon overcoats (COCs) having interspersed nanostructures by the filtered cathodic vacuum arc (FCVA) process can be an effective approach to achieve the desired target. In this work, by employing a novel bi-level surface modification approach using FCVA, the formation of a high sp(3) bonded ultrathin (~1.7 nm) amorphous carbon overcoat with interspersed graphene/fullerene-like nanostructures, grown on magnetic hard disk media, is reported. The in-depth spectroscopic and microscopic analyses by high resolution transmission electron microscopy, scanning tunneling microscopy, time-of-flight secondary ion mass spectrometry, and Raman spectroscopy support the observed findings. Despite a reduction of ~37% in COC thickness, the FCVA-processed thinner COC (~1.7 nm) shows promising functional performance in terms of lower coefficient of friction (~0.25), higher wear resistance, lower surface energy, excellent hydrophobicity and similar/better oxidation corrosion resistance than current commercial COCs of thickness ~2.7 nm. The surface and tribological properties of FCVA-deposited COC was further improved after deposition of lubricant layer.

Ultrathin Carbon with Interspersed Graphene/Fullerene-like Nanostructures: A Durable Protective Overcoat for High Density Magnetic Storage

NASA Astrophysics Data System (ADS)

Dwivedi, Neeraj; Satyanarayana, Nalam; Yeo, Reuben J.; Xu, Hai; Ping Loh, Kian; Tripathy, Sudhiranjan; Bhatia, Charanjit S.

2015-06-01

One of the key issues for future hard disk drive technology is to design and develop ultrathin (<2 nm) overcoats with excellent wear- and corrosion protection and high thermal stability. Forming carbon overcoats (COCs) having interspersed nanostructures by the filtered cathodic vacuum arc (FCVA) process can be an effective approach to achieve the desired target. In this work, by employing a novel bi-level surface modification approach using FCVA, the formation of a high sp3 bonded ultrathin (~1.7 nm) amorphous carbon overcoat with interspersed graphene/fullerene-like nanostructures, grown on magnetic hard disk media, is reported. The in-depth spectroscopic and microscopic analyses by high resolution transmission electron microscopy, scanning tunneling microscopy, time-of-flight secondary ion mass spectrometry, and Raman spectroscopy support the observed findings. Despite a reduction of ~37 % in COC thickness, the FCVA-processed thinner COC (~1.7 nm) shows promising functional performance in terms of lower coefficient of friction (~0.25), higher wear resistance, lower surface energy, excellent hydrophobicity and similar/better oxidation corrosion resistance than current commercial COCs of thickness ~2.7 nm. The surface and tribological properties of FCVA-deposited COC was further improved after deposition of lubricant layer.

Synthesis and characterization of self-bridged silver vanadium oxide/CNTs composite and its enhanced lithium storage performance.

PubMed

Liang, Liying; Liu, Haimei; Yang, Wensheng

2013-02-07

The improvement of the electrochemical properties of electrode materials with large capacity and good capacity retention is becoming an important task in the field of lithium ion batteries (LIBs). We designed a function-oriented hybrid material consisting of silver vanadium oxide (β-AgVO(3)) nanowires modified with uniform Ag nanoparticles and multi-walled carbon nanotubes (CNTs) as a high-performance cathode material for LIBs. The Ag nanoparticles which precipitated automatically in the synthetic process act as a bridge between the β-AgVO(3) nanowires and CNTs, creating a self-bridged network structure. The Ag particles at the junction of the nanowires and CNTs facilitate electron transport from the CNTs to the nanowires, and thereby improve the electrical conductivity of the β-AgVO(3) nanowires and the composite. Moreover, the self-bridged network is hierarchically porous with a high surface area. When used as a cathode material, this composite electrode reveals high discharge capacities, excellent rate capability, and good cycling stability. The improved performance of the composite arises from its unique nanosized β-AgVO(3) nanowires with short diffusion pathway for lithium ions, efficient electron collection and transfer in the presence of Ag nanoparticles, together with excellent electrical conductivity of CNTs.

Ultrathin Carbon with Interspersed Graphene/Fullerene-like Nanostructures: A Durable Protective Overcoat for High Density Magnetic Storage

PubMed Central

Dwivedi, Neeraj; Satyanarayana, Nalam; Yeo, Reuben J.; Xu, Hai; Ping Loh, Kian; Tripathy, Sudhiranjan; Bhatia, Charanjit S.

2015-01-01

One of the key issues for future hard disk drive technology is to design and develop ultrathin (<2 nm) overcoats with excellent wear- and corrosion protection and high thermal stability. Forming carbon overcoats (COCs) having interspersed nanostructures by the filtered cathodic vacuum arc (FCVA) process can be an effective approach to achieve the desired target. In this work, by employing a novel bi-level surface modification approach using FCVA, the formation of a high sp3 bonded ultrathin (~1.7 nm) amorphous carbon overcoat with interspersed graphene/fullerene-like nanostructures, grown on magnetic hard disk media, is reported. The in-depth spectroscopic and microscopic analyses by high resolution transmission electron microscopy, scanning tunneling microscopy, time-of-flight secondary ion mass spectrometry, and Raman spectroscopy support the observed findings. Despite a reduction of ~37 % in COC thickness, the FCVA-processed thinner COC (~1.7 nm) shows promising functional performance in terms of lower coefficient of friction (~0.25), higher wear resistance, lower surface energy, excellent hydrophobicity and similar/better oxidation corrosion resistance than current commercial COCs of thickness ~2.7 nm. The surface and tribological properties of FCVA-deposited COC was further improved after deposition of lubricant layer. PMID:26109208

Effect of ascorbic acid on the stability of beta-carotene and capsanthin in paprika (Capsicum annuum) powder.

PubMed

Morais, H; Rodrigues, P; Ramos, C; Forgács, E; Cserháti, T; Oliveira, J

2002-10-01

The effect of ascorbic acid, light, and storage on the stability of the pigments beta-carotene and capsanthin in red pepper (Capsicum annuum) powder has been elucidated by determining the amount of pigment in samples treated by various concentrations of ascorbic acid. Determination of pigment concentration has been performed after different storage times using high-performance liquid chromatography. The dependence of the concentration of pigments on the concentration of ascorbic acid, presence of light and the storage time has been assessed by stepwise regression analysis. The concentration of pigments decreased at longer storage time and increased at higher concentration of ascorbic acid, beta-carotene being more sensitive towards storage time and concentration of ascorbic acid than capsanthin. Interaction between the effects of light and storage time, and light and concentration of ascorbic acid has been established.

Advanced Electrode Materials for High Energy Next Generation Li ion Batteries

NASA Astrophysics Data System (ADS)

Hayner, Cary Michael

Lithium ion batteries are becoming an increasingly ubiquitous part of modern society. Since their commercial introduction by Sony in 1991, lithium-ion batteries have grown to be the most popular form of electrical energy storage for portable applications. Today, lithium-ion batteries power everything from cellphones and electric vehicles to e-cigarettes, satellites, and electric aircraft. Despite the commercialization of lithium-ion batteries over twenty years ago, it remains the most active field of energy storage research for its potential improvement over current technology. In order to capitalize on these opportunities, new materials with higher energy density and storage capacities must be developed. Unfortunately, most next-generation materials suffer from rapid capacity degradation or severe loss of capacity when rapidly discharged. In this dissertation, the development of novel anode and cathode materials for advanced high-energy and high-power lithium-ion batteries is reported. In particular, the application of graphene-based materials to stabilize active material is emphasized. Graphene, a unique two-dimensional material composed of atomically thin carbon sheets, has shown potential to address unsatisfactory rate capability, limited cycling performance and abrupt failure of these next-generation materials. This dissertation covers four major subjects: development of silicon-graphene composites, impact of carbon vacancies on graphene high-rate performance, iron fluoride-graphene composites, and ternary iron-manganese fluoride synthesis. Silicon is considered the most likely material to replace graphite as the anode active material for lithium-ion batteries due to its ability to alloy with large amounts of lithium, leading to significantly higher specific capacities than the graphite standard. However, Si also expands in size over 300% upon lithiation, leading to particle fracture and isolation from conductive support, resulting in cell failure within a few charge-discharge cycles. To stabilize silicon materials, composites of silicon nanoparticles were dispersed between graphene sheets and supported by a 3-D network of graphite formed by reconstituted regions of graphene stacks. These free-standing, self-supported composites exhibited excellent Li-ion storage capacities higher than 2200 mAh/g and good cycling stability. In order to improve the advantages graphene can provide as a 3-D scaffold, carbon vacancies were introduced into the basal planes via an acid-oxidation treatment. These vacancies markedly enhance the rate performance of graphene materials as well as silicon-graphene composites. Silicon-graphene composites containing carbon vacancies achieved high accessible storage capacities at fast charge/discharge rates that rival supercapacitor performance while maintaining good cycling stability. Optimal carbon vacancy size and density were determined. Graphene composites were also formed with iron trifluoride (FeF 3), a high-energy cathode material with ability to store up to 712 mAh/g capacity, over 3X more than current state-of-the-art cathode materials. A facile route that combines co-assembly and photothermal reduction was developed to synthesize free-standing, flexible FeF3/graphene papers. The papers contained a uniform dispersion of FeF3 nanoparticles (< 40 nm) and open ion diffusion channels in the porous, conducting network of graphene sheets that resulted in a flexible paper cathode with high charge storage capacity, rate, and cycling performance, without the need for other carbon additives or binder. Free-standing FeF3/graphene composites showed a high storage capacity of >400 mAh/g and improved cycling performance compared to bare FeF3 particles. Lastly, novel ternary iron-manganese fluoride (FexMn 1-xF2) cathode materials were synthesized via a convenient, bottom-up solution-phase synthesis which allowed control of particle size, shape, and surface morphology. The synthesized materials exhibited nanoscale features with average particle size of 20-40 nm. These ternary metal composites exhibited key, desirable properties for next-generation Li-ion battery cathode materials. The described process constituted a translatable route to large-scale production of ternary metal fluoride nanoparticles.

Synthesis of nanostructured materials by using metal-cyanide coordination polymers and their lithium storage properties

NASA Astrophysics Data System (ADS)

Nie, Ping; Shen, Laifa; Luo, Haifeng; Li, Hongsen; Xu, Guiyin; Zhang, Xiaogang

2013-10-01

Herein, we demonstrate a novel and simple two-step process for preparing LiCoO2 nanocrystals by using a Prussian blue analogue Co3[Co(CN)6]2 as a precursor. The resultant LiCoO2 nanoparticles possess single crystalline nature and good uniformity with an average size of ca. 360 nm. The unique nanostructure of LiCoO2 provides relatively shorter Li+ diffusion pathways, thus facilitating the fast kinetics of electrochemical reactions. As a consequence, high reversible capacity, excellent cycling stability and rate capability are achieved with these nanocrystals as cathodes for lithium storage. The LiCoO2 nanocrystals deliver specific capacities of 154.5, 135.8, 119, and 100.3 mA h g-1 at 0.2, 0.4, 1, and 2 C rates, respectively. Even at a high current density of 4 C, a reversible capacity of 87 mA h g-1 could be maintained. Importantly, a capacity retention of 83.4% after 100 cycles is achieved at a constant discharge rate of 1 C. Furthermore, owing to facile control of the morphology and size of Prussian blue analogues by varying process parameters, as well as the tailored design of multi-component metal-cyanide hybrid coordination polymers, with which we have successfully prepared porous Fe2O3@NixCo3-xO4 nanocubes, one of the potential anode materials for lithium-ion batteries, such a simple and scalable approach could also be applied to the synthesis of other nanomaterials for energy storage devices.Herein, we demonstrate a novel and simple two-step process for preparing LiCoO2 nanocrystals by using a Prussian blue analogue Co3[Co(CN)6]2 as a precursor. The resultant LiCoO2 nanoparticles possess single crystalline nature and good uniformity with an average size of ca. 360 nm. The unique nanostructure of LiCoO2 provides relatively shorter Li+ diffusion pathways, thus facilitating the fast kinetics of electrochemical reactions. As a consequence, high reversible capacity, excellent cycling stability and rate capability are achieved with these nanocrystals as cathodes for lithium storage. The LiCoO2 nanocrystals deliver specific capacities of 154.5, 135.8, 119, and 100.3 mA h g-1 at 0.2, 0.4, 1, and 2 C rates, respectively. Even at a high current density of 4 C, a reversible capacity of 87 mA h g-1 could be maintained. Importantly, a capacity retention of 83.4% after 100 cycles is achieved at a constant discharge rate of 1 C. Furthermore, owing to facile control of the morphology and size of Prussian blue analogues by varying process parameters, as well as the tailored design of multi-component metal-cyanide hybrid coordination polymers, with which we have successfully prepared porous Fe2O3@NixCo3-xO4 nanocubes, one of the potential anode materials for lithium-ion batteries, such a simple and scalable approach could also be applied to the synthesis of other nanomaterials for energy storage devices. Electronic supplementary information (ESI) available: Detailed experimental procedures and supplementary figures. See DOI: 10.1039/c3nr03289b

Effect of storage time, temperature, antioxidant and thawing on fatty acid composition of plasma, serum and red blood cells - A pilot biobank study.

PubMed

Araujo, Pedro; Bjørkkjær, Tormod; Frøyland, Livar; Waagbø, Rune

2018-02-01

It studies on the factors that affect the stability of fatty acid profiles from human blood specimens are generally performed by evaluating the effect of a single factor on an individual fatty acid and excluding a considerable amount of data from the total fatty acid profiles. The stability of fatty acids from plasma, serum and red blood cells (RBC) was evaluated in terms of time, temperature, antioxidant and thawing. The fatty acids were methylated and analyzed by gas chromatography. The large volume of data is evaluated simultaneously and automatically by observing an Excel-based colour scale that indicates whether the fatty acid profiles have changed significantly as a result of the storage time (0-52weeks), temperature (-20°C/-80°C), butylated hydroxytoluene (BHT) antioxidant (presence/absence) or thawing (single/multiple). Fatty acids from plasma were stable at both temperatures (-20°C/-80°C) regardless of BHT. Fatty acids from serum without BHT degrades faster at -80°C than -20°C and fatty acids from RBC without BHT degrades faster at -20°C than -80°C. Addition of BHT inhibits this effect in serum and RBC. Multiple thawing of RBC without BHT demonstrated that polyunsaturated fatty acids were generally more susceptible for changes at -80°C than at -20°C while BHT prevents partially this effect. This study draws attention to the importance of pre-analytical considerations when storing blood samples in biobanks and the need of careful judgments when analyzing fatty acids profiles. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Intertwined nanocarbon and manganese oxide hybrid foam for high-energy supercapacitors.

PubMed

Wang, Wei; Guo, Shirui; Bozhilov, Krassimir N; Yan, Dong; Ozkan, Mihrimah; Ozkan, Cengiz S

2013-11-11

Rapid charging and discharging supercapacitors are promising alternative energy storage systems for applications such as portable electronics and electric vehicles. Integration of pseudocapacitive metal oxides with single-structured materials has received a lot of attention recently due to their superior electrochemical performance. In order to realize high energy-density supercapacitors, a simple and scalable method is developed to fabricate a graphene/MWNT/MnO2 nanowire (GMM) hybrid nanostructured foam, via a two-step process. The 3D few-layer graphene/MWNT (GM) architecture is grown on foamed metal foils (nickel foam) via ambient pressure chemical vapor deposition. Hydrothermally synthesized α-MnO2 nanowires are conformally coated onto the GM foam by a simple bath deposition. The as-prepared hierarchical GMM foam yields a monographical graphene foam conformally covered with an intertwined, densely packed CNT/MnO2 nanowire nanocomposite network. Symmetrical electrochemical capacitors (ECs) based on GMM foam electrodes show an extended operational voltage window of 1.6 V in aqueous electrolyte. A superior energy density of 391.7 Wh kg(-1) is obtained for the supercapacitor based on the GMM foam, which is much higher than ECs based on GM foam only (39.72 Wh kg(-1) ). A high specific capacitance (1108.79 F g(-1) ) and power density (799.84 kW kg(-1) ) are also achieved. Moreover, the great capacitance retention (97.94%) after 13 000 charge-discharge cycles and high current handability demonstrate the high stability of the electrodes of the supercapacitor. These excellent performances enable the innovative 3D hierarchical GMM foam to serve as EC electrodes, resulting in energy-storage devices with high stability and power density in neutral aqueous electrolyte. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

1D Ni-Co oxide and sulfide nanoarray/carbon aerogel hybrid nanostructures for asymmetric supercapacitors with high energy density and excellent cycling stability.

PubMed

Hao, Pin; Tian, Jian; Sang, Yuanhua; Tuan, Chia-Chi; Cui, Guanwei; Shi, Xifeng; Wong, C P; Tang, Bo; Liu, Hong

2016-09-15

The fabrication of supercapacitor electrodes with high energy density and excellent cycling stability is still a great challenge. A carbon aerogel, possessing a hierarchical porous structure, high specific surface area and electrical conductivity, is an ideal backbone to support transition metal oxides and bring hope to prepare electrodes with high energy density and excellent cycling stability. Therefore, NiCo 2 S 4 nanotube array/carbon aerogel and NiCo 2 O 4 nanoneedle array/carbon aerogel hybrid supercapacitor electrode materials were synthesized by assembling Ni-Co precursor needle arrays on the surface of the channel walls of hierarchical porous carbon aerogels derived from chitosan in this study. The 1D nanostructures grow on the channel surface of the carbon aerogel vertically and tightly, contributing to the enhanced electrochemical performance with ultrahigh energy density. The energy density of NiCo 2 S 4 nanotube array/carbon aerogel and NiCo 2 O 4 nanoneedle array/carbon aerogel hybrid asymmetric supercapacitors can reach up to 55.3 Wh kg -1 and 47.5 Wh kg -1 at a power density of 400 W kg -1 , respectively. These asymmetric devices also displayed excellent cycling stability with a capacitance retention of about 96.6% and 92% over 5000 cycles.

Interlinked multiphase Fe-doped MnO2 nanostructures: a novel design for enhanced pseudocapacitive performance

NASA Astrophysics Data System (ADS)

Wang, Ziya; Wang, Fengping; Li, Yan; Hu, Jianlin; Lu, Yanzhen; Xu, Mei

2016-03-01

Structure designing and morphology control can lead to high performance pseudocapacitive materials for supercapacitors. In this work, we have designed interlinked multiphase Fe-doped MnO2 nanostructures (α-MnO2/R-MnO2/ε-MnO2) to enhance the electrochemical properties by a facile method. These hierarchical hollow microspheres assembled by interconnected nanoflakes, and with plenty of porous nanorods radiating from the spherical shells were hydrothermally obtained. The supercapacitor electrode prepared from the unique construction exhibits outstanding specific capacitance of 267.0 F g-1 even under a high mass loading (~5 mg cm-2). Obviously improved performances compared to pure MnO2 are also demonstrated with a good rate capability, high energy density (1.30 mW h cm-3) and excellent cycling stability of 100% capacitance retention after 2000 cycles at 2 A g-1. The synergistic effects of alternative crystal structures, appropriate crystallinity and optimal morphology are identified to be responsible for the observations. This rational multiphase composite strategy provides a promising idea for materials scientists to design and prepare scalable electrode materials for energy storage devices.Structure designing and morphology control can lead to high performance pseudocapacitive materials for supercapacitors. In this work, we have designed interlinked multiphase Fe-doped MnO2 nanostructures (α-MnO2/R-MnO2/ε-MnO2) to enhance the electrochemical properties by a facile method. These hierarchical hollow microspheres assembled by interconnected nanoflakes, and with plenty of porous nanorods radiating from the spherical shells were hydrothermally obtained. The supercapacitor electrode prepared from the unique construction exhibits outstanding specific capacitance of 267.0 F g-1 even under a high mass loading (~5 mg cm-2). Obviously improved performances compared to pure MnO2 are also demonstrated with a good rate capability, high energy density (1.30 mW h cm-3) and excellent cycling stability of 100% capacitance retention after 2000 cycles at 2 A g-1. The synergistic effects of alternative crystal structures, appropriate crystallinity and optimal morphology are identified to be responsible for the observations. This rational multiphase composite strategy provides a promising idea for materials scientists to design and prepare scalable electrode materials for energy storage devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08857g

Development of spray-dried co-precipitate of amorphous celecoxib containing storage and compression stabilizers.

PubMed

Dhumal, Ravindra S; Shimpi, Shamkant L; Paradkar, Anant R

2007-09-01

The purpose of this study was to obtain an amorphous system with minimum unit operations that will prevent recrystallization of amorphous drugs since preparation, during processing (compression) and further storage. Amorphous celecoxib, solid dispersion (SD) of celecoxib with polyvinyl pyrrollidone (PVP) and co-precipitate with PVP and carrageenan (CAR) in different ratios were prepared by the spray drying technique and compressed into tablets. Saturation solubility and dissolution studies were performed to differentiate performance after processing. Differential scanning calorimetry and X-ray powder difraction revealed the amorphous form of celecoxib, whereas infrared spectroscopy revealed hydrogen bonding between celecoxib and PVP. The dissolution profile of the solid dispersion and co-precipitate improved compared to celecoxib and amorphous celecoxib. Amorphous celecoxib was not stable on storage whereas the solid dispersion and co-precipitate powders were stable for 3 months. Tablets of the solid dispersion of celecoxib with PVP and physical mixture with PVP and carrageenan showed better resistance to recrystallization than amorphous celecoxib during compression but recrystallized on storage. However, tablets of co-precipitate with PVP and carageenan showed no evidence of crystallinity during stability studies with comparable dissolution profiles. This extraordinary stability of spray-dried co-precipitate tablets may be attributed to the cushioning action provided by the viscoelastic polymer CAR and hydrogen bonding interaction between celecoxib and PVP. The present study demonstrates the synergistic effect of combining two types of stabilizers, PVP and CAR, on the stability of amorphous drug during compression and storage as compared to their effect when used alone.

Prawn Shell Derived Chitin Nanofiber Membranes as Advanced Sustainable Separators for Li/Na-Ion Batteries.

PubMed

Zhang, Tian-Wen; Shen, Bao; Yao, Hong-Bin; Ma, Tao; Lu, Lei-Lei; Zhou, Fei; Yu, Shu-Hong

2017-08-09

Separators, necessary components to isolate cathodes and anodes in Li/Na-ion batteries, are consumed in large amounts per year; thus, their sustainability is a concerning issue for renewable energy storage systems. However, the eco-efficient and environmentally friendly fabrication of separators with a high mechanical strength, excellent thermal stability, and good electrolyte wettability is still challenging. Herein, we reported the fabrication of a new type of separators for Li/Na-ion batteries through the self-assembly of eco-friendly chitin nanofibers derived from prawn shells. We demonstrated that the pore size in the chitin nanofiber membrane (CNM) separator can be tuned by adjusting the amount of pore generation agent (sodium dihydrogen citrate) in the self-assembly process of chitin nanofibers. By optimizing the pore size in CNM separators, the electrochemical performance of the LiFePO 4 /Li half-cell with a CNM separator is comparable to that with a commercialized polypropylene (PP) separator. More attractively, the CNM separator showed a much better performance in the LiFePO 4 /Li cell at 120 °C and Na 3 V 2 (PO 4 ) 3 /Na cell than the PP separator. The proposed fabrication of separators by using natural raw materials will play a significant contribution to the sustainable development of renewable energy storage systems.