High performance binder-free SiO x/C composite LIB electrode made of SiO x and lignin

DOE PAGES

Chen, Tao; Hu, Jiazhi; Zhang, Long; ...

2017-07-19

A high performance binder-free SiO x/C composite electrode was synthesized by mixing SiO x particles and Kraft lignin in a cryo-mill followed by heat treatment at 600 °C. After the heat treatment, lignin formed a conductive matrix hosting SiO x particles, ensuring electronic conductivity, connectivity, and accommodation of volume changes during lithiation/delithiation. As the result, no conventional binder or conductive agent was necessary. When electrochemically cycled, the composite electrode delivered excellent performance, maintaining ~900 mAh g -1 after 250 cycles at a rate of 200 mA g -1, and good rate capability. The robustness of the electrode was also examinedmore » by post-cycling SEM images, where few cracks were observed. The excellent electrochemical performance can be attributed to the comparatively small volume change of SiO x-based electrodes (160%) and the flexibility of the lignin derived carbon matrix to accommodate the volume change. In conclusion, this work should stimulate further interests in using bio-renewable resources in making advanced electrochemical energy storage systems.« less

Synthesis of hollow NiCo2O4 nanospheres with large specific surface area for asymmetric supercapacitors.

PubMed

Xu, Kaibing; Yang, Jianmao; Hu, Junqing

2018-02-01

Hollow micro-/nanostructured electrode materials with high active surface area are highly desirable for achieving outstanding electrochemical properties. Herein, we report the successful synthesis of hierarchical hollow NiCo 2 O 4 nanospheres with high surface area as electrode materials for supercapacitors. Electrochemical measurements prove that such electrode materials exhibit excellent electrochemical behavior with a specific capacitance reaching 1229 F/g at 1 A/g, remarkable rate performance (∼83.6% retention from 1 to 25 A/g) and good cycling performance (86.3% after 3000 cycles). Furthermore, the asymmetric supercapacitor is fabricated with hollow NiCo 2 O 4 nanospheres electrode and activated carbon (AC) electrode as the positive and negative, respectively. This device exhibits a maximum energy density of 21.5 W h/kg, excellent cycling performance and coulombic efficiency. The results show that hollow NiCo 2 O 4 nanosphere electrode is a promising electrode material for the future application in high performance supercapacitors. Copyright © 2017 Elsevier Inc. All rights reserved.

High performance binder-free SiO x/C composite LIB electrode made of SiO x and lignin

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

Chen, Tao; Hu, Jiazhi; Zhang, Long

A high performance binder-free SiO x/C composite electrode was synthesized by mixing SiO x particles and Kraft lignin in a cryo-mill followed by heat treatment at 600 °C. After the heat treatment, lignin formed a conductive matrix hosting SiO x particles, ensuring electronic conductivity, connectivity, and accommodation of volume changes during lithiation/delithiation. As the result, no conventional binder or conductive agent was necessary. When electrochemically cycled, the composite electrode delivered excellent performance, maintaining ~900 mAh g -1 after 250 cycles at a rate of 200 mA g -1, and good rate capability. The robustness of the electrode was also examinedmore » by post-cycling SEM images, where few cracks were observed. The excellent electrochemical performance can be attributed to the comparatively small volume change of SiO x-based electrodes (160%) and the flexibility of the lignin derived carbon matrix to accommodate the volume change. In conclusion, this work should stimulate further interests in using bio-renewable resources in making advanced electrochemical energy storage systems.« less

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.

Electrolytes for Use in High Energy Lithium-ion Batteries with Wide Operating Temperature Range

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

2012-01-01

Met programmatic milestones for program. Demonstrated improved performance with wide operating temperature electrolytes containing ester co-solvents (i.e., methyl butyrate) containing electrolyte additives in A123 prototype cells: Previously demonstrated excellent low temperature performance, including 11C rates at -30 C and the ability to perform well down to -60 C. Excellent cycle life at room temperature has been displayed, with over 5,000 cycles being demonstrated. Good high temperature cycle life performance has also been achieved. Demonstrated improved performance with methyl propionate-containing electrolytes in large capacity prototype cells: Demonstrated the wide operating temperature range capability in large cells (12 Ah), successfully scaling up technology from 0.25 Ah size cells. Demonstrated improved performance at low temperature and good cycle life at 40 C with methyl propionate-based electrolyte containing increasing FEC content and the use of LiBOB as an additive. Utilized three-electrode cells to investigate the electrochemical characteristics of high voltage systems coupled with wide operating temperature range electrolytes: From Tafel polarization measurements on each electrode, it is evident the NMC-based cathode displays poor lithium kinetics (being the limiting electrode). The MB-based formulations containing LiBOB delivered the best rate capability at low temperature, which is attributed to improved cathode kinetics. Whereas, the use of lithium oxalate as an additive lead to the highest reversible capacity and lower irreversible losses.

Facile synthesis of mesoporous NiO nanoflakes on graphene foam and its electrochemical properties for supercapacitor application

NASA Astrophysics Data System (ADS)

Lv, Jinlong; Wang, Zhuqing; Miura, Hideo

2018-01-01

Many NiO platelets were formed on Ni foam after hydrothermal process, while flower-like NiO with many small mesoporous nanoflakes was obtained on the surface of graphene foam. Electrochemical results showed that the NiO/graphene composites exhibited very high specific capacitance 1062 F g-1 at 1 A g-1 and excellent cycling stability (90.6% capacitance retention after 5000 cycles at 1 A g-1). The promising NiO/graphene composites exhibited higher supercapacitor performance than NiO platelets on Ni foam. The excellent supercapacitor performance of the former should be attributed to the 3D graphene conductive network and the mesoporous NiO nanoflakes which promoted efficient charge transport and electrolyte diffusion.

The effect of nitrogen on the cycling performance in thin-film Si{sub 1-x}N{sub x} anode

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

Ahn, Donggi; Kim, Chunjoong; Lee, Joon-Gon

2008-09-15

The effects of nitrogen on the electrochemical properties of silicon-nitrogen (Si{sub 1-x}N{sub x}) thin films were examined in terms of their initial capacities and cycling properties. In particular, Si{sub 0.76}N{sub 0.24} thin films showed negligible initial capacity but an abrupt capacity increase to {approx}2300 mA h/g after {approx}650 cycles. The capacity of pure Si thin films was deteriorated to {approx}20% of the initial level after 200 cycles between 0.02 and 1.2 V at 0.5 C (1 C=4200 mA/g), whereas the Si{sub 0.76}N{sub 0.24} thin films exhibited excellent cycle-life performance after {approx}650 cycles. In addition, the Si{sub 0.76}N{sub 0.24} thin filmsmore » at 50 deg. C showed an abrupt capacity increase at an earlier stage of only {approx}30 cycles. The abnormal electrochemical behaviors in the Si{sub 0.76}N{sub 0.24} thin films were demonstrated to be correlated with the formation of Li{sub 3}N and Si{sub 3}N{sub 4}. - Graphical abstract: The Si{sub 0.76}N{sub 0.24} thin films showed negligible initial capacity, but an abrupt capacity increase to {approx}2300 mA h/g after {approx}650 cycles, followed by excellent cycle-life performance. This abnormal electrochemical behavior was demonstrated to be correlated with the formation of Li{sub 3}N and Si{sub 3}N{sub 4}.« 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.

Panasonic Small Cell Testing for AHPS

NASA Technical Reports Server (NTRS)

Pearson, C.; Blackmore, P.; Lain, M.; Walpole, A.; Darcy, Eric

2006-01-01

AEA selection and successful Interim Design Review for AHPS proves maturity of small cell approach for very large batteries. Cells show excellent opportunity for battery mass reduction for AHPS and other low cycle applications. Lack of cycle and extended calendar life make EOL battery performance difficult (AHPS 8 year mission). Preliminary design, AEA retained SONY 18650HC cell as baseline: a) Well characterized performance; b) Wealth of safety test data.

A low cost, high energy density and long cycle life potassium-sulfur battery for grid-scale energy storage

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

Lu, Xiaochuan; Bowden, Mark E.; Sprenkle, Vincent L.

2015-08-15

Alkali metal-sulfur batteries are attractive for energy storage applications because of their high energy density. Among the batteries, lithium-sulfur batteries typically use liquid in the battery electrolyte, which causes problems in both performance and safety. Sodium-sulfur batteries can use a solid electrolyte such as beta alumina but this requires a high operating temperature. Here we report a novel potassium-sulfur battery with K+-conducting beta-alumina as the electrolyte. Our studies indicate that liquid potassium exhibits much better wettability on the surface of beta-alumina compared to liquid sodium at lower temperatures. Based on this observation, we develop a potassium-sulfur battery that can operatemore » at as low as 150°C with excellent performance. In particular, the battery shows excellent cycle life with negligible capacity fade in 1000 cycles because of the dense ceramic membrane. This study demonstrates a new battery with a high energy density, long cycle life, low cost and high safety, which is ideal for grid-scale energy storage.« less

An Asymmetric Supercapacitor Based on Activated Porous Carbon Derived from Walnut Shells and NiCo₂O₄ Nanoneedle Arrays Electrodes.

PubMed

Wang, Wei; Qi, Jiqiu; Sui, Yanwei; He, Yezeng; Meng, Qingkun; Wei, Fuxiang; Jin, Yunxue

2018-08-01

A facile method was utilized to convert a common biomass of walnut shells into activated porous carbon by carbonization and activation with nitricacid treatment. The obtained activated carbon (WSs-2) exhibited excellent electrochemical performance with high specific capacitance of 137 F · g-1 at 1 A · g-1 and super cycling performance of 96% capacitance retention at 5 A · g-1 after 5000 cycles. In addition, NiCo2O4 nanoneedle arrays with good electrochemical properties were successfully prepared by a simple hydrothermal method. An aqueous asymmetric supercapacitor (ASC) device based on WSs-2 and NiCo2O4 was assembled, which delivered 21 Wh · kg-1 at a power density of 424.5 W · kg-1, and maintained 19 Wh · kg-1 at power density of 4254 W · kg-1 as well as excellent cycling stability of 99.3% capacitance retention after 5000 cycles at 4 A · g-1. Through this method, low-cost, environmentally friendly and large-scale carbon materials can be fabricated and applied in supercapacitor electrodes.

Polyanthraquinone-Based Organic Cathode for High-Performance Rechargeable Magnesium-Ion Batteries

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

Pan, Baofei; Huang, Jinhua; Feng, Zhenxing

2016-05-09

Two anthraquinone-based polymers aiming at improving the capacity and voltage of magnesium ion batteries, were synthesized and characterized. The excellent battery cycling performance was demonstrated with the electrolyte consisting of magnesium bis(hexamethyldisilazide) and magnesium chloride.

Cycle life testing of lithium-ion batteries for small satellite LEO space missions

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

Mayer, S.T.; Feikert, J.H.; Kaschmitter, J.L.

1993-08-16

In 1990, Sony corporation announced their intention to manufacture a rechargeable lithium ion battery, based on the intercalation of lithium ions into a carbonaceous anode. The cells were first introduced for portable telephone use in June, 1991. (1) A 3.6V average cell voltage (4.1-2.75V range); (2) Excellent cycle life (1200 @ 100% DOD); (3) Good capacity retention (70% after 6 months); (4) Wide temperature range performance ({minus}20 to +60{degrees}C); (5) Excellent Discharge rate (82% capacity at 30 min. discharge rate); (6) Excellent Charge rate (100% Charge in <3 hrs); and (7) High energy density (264 W*hr/1 and 120 Whr/kg formore » ``D`` size cell. These specifications show significant promise for application of these batteries in low earth orbit (LEO) small satellites, particularly when compared to existing NiH{sub 2} and NiCd technology. The very high energy density and specific energy will reduce power system volume and weight. The wide temperature range enables simpler thermal design, particularly for new, small, high power satellites. The materials used in the lithium ion batteries are relatively inexpensive and benign, so that we expect costs to come down substantially in the future. The specified cycle life at 100% DOD is also 50% longer than most NiCds, so low DOD (depth of discharge) performance could be substantial. This study was undertaken to: (a) assess the feasibility for using lithium ion cells on small satellite LEO missions and (b) verify the claims of the manufacturer. This was accomplished by performing a detailed autopsy and various depth of discharge and rate tests on the cells. Of special interest was the cycle life performance of these cell at various depths of discharge DOD`s, to get an initial measure of the reduction in capacity fade with cycle conditions. Low DOD`s are used to extend the life of all batteries used in a space application.« less

Metal coordination polymer derived mesoporous Co3O4 nanorods with uniform TiO2 coating as advanced anodes for lithium ion batteries.

PubMed

Geng, Hongbo; Ang, Huixiang; Ding, Xianguang; Tan, Huiteng; Guo, Guile; Qu, Genlong; Yang, Yonggang; Zheng, Junwei; Yan, Qingyu; Gu, Hongwei

2016-02-07

In this work, a one-dimensional Co3O4@TiO2 core-shell electrode material with superior electrochemical performance is fabricated by a convenient and controllable route. The approach involves two main steps: the homogeneous deposition of polydopamine and TiO2 layers in sequence on the cobalt coordination polymer and the thermal decomposition of the polymer matrix. The as-prepared electrode material can achieve excellent electrochemical properties and stability as an anode material for lithium ion batteries, such as a high specific capacity of 1279 mA h g(-1), good cycling stability (around 803 mA h g(-1) at a current density of 200 mA g(-1) after 100 cycles), and stable rate performance (around 520 mA h g(-1) at a current density of 1000 mA g(-1)). This dramatic electrochemical performance is mainly attributed to the excellent structural characteristics, which could improve the electrical conductivity and lithium ion mobility, as well as electrolyte permeability and architectural stability during cycling.

A F-doped tree-like nanofiber structural poly-m-phenyleneisophthalamide separator for high-performance lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

Deng, Nanping; Wang, Yan; Yan, Jing; Ju, Jingge; Li, Zongjie; Fan, Lanlan; Zhao, Huijuan; Kang, Weimin; Cheng, Bowen

2017-09-01

In this study, F-doped tree-like nanofiber structural poly-m-phenyleneisophthalamide (PMIA) membranes are prepared via one-step electrospinning approach and their application performance as separators for lithium-sulfur batteries are discussed. The F-doped PMIA membrane can be regarded as matrix to form gel polymer electrolyte. The F doping endows the PMIA membranes with extraordinary high electrolyte uptake, excellent ability of preserving the liquid electrolyte and forceful chemisorption to polysulfides. And the tree-like structure effectively blocks polysulfides by the physical confinement. The lithium-sulfur cell with the F-doped PMIA separator exhibits high first-cycle discharge capacity of 1222.5 mAh g-1 and excellent cycling stability with good capacity retention of 745.7 mAh g-1 and coulombic efficiency of 97.97% after 800 cycles. The remarkable performance can be ascribed to the suppressed shuttle effects through both the physical trapping of polysulfides by the gel polymer electrolyte based on matrix with F-doped PMIA membrane and the tree-like structure in a working cell.

Demonstration of active vibration control on a stirling-cycle cryocooler testbed

NASA Technical Reports Server (NTRS)

Johnson, Bruce G.; Flynn, Frederick J.; Gaffney, Monique S.; Johnson, Dean L.; Ross, Ronald G., Jr.

1992-01-01

SatCon Technology Corporation has demonstrated excellent vibration reduction performance using active control on the JPL Stirling-cycle cryocooler testbed. The authors address the use of classical narrowband feedback control to meet the cryocooler vibration specifications using one cryocooler in a self-cancellation configuration. Similar vibration reduction performance was obtained using a cryocooler back-to-back configuration by actively controlling a reaction mass actuator that was used to mimic the second cooler.

Sales Training for Army Recruiter Success: Modeling the Sales Strategies and Skills of Excellent Recruiters

DTIC Science & Technology

1987-11-01

strategies used by excellent Army recruiters. Neurolinguistic programming (NLP) was used as the protocol for modeling performance and acquiring...Behavioral and Social Sciences 3001 Eisenhower Avenue, Alexandria, VA 22333-5600 10. PROGRAM ELEMENT. PROJECT. TASK ARE* 4 WORK UNIT...Modeling ’Expert knowledge,, Neurolinguistics Knowledge engineering; Recruiting Sales, &’ Sales cycle Sales skills Sales strategies 20

Preparation of layered graphene and tungsten oxide hybrids for enhanced performance supercapacitors.

PubMed

Xing, Ling-Li; Huang, Ke-Jing; Fang, Lin-Xia

2016-11-01

Tungsten oxide (WO 3 ), which was originally poor in capacitive performance, is made into an excellent electrode material for supercapacitors by dispersing it on graphene (Gr). The obtained Gr-WO 3 hybrids are characterized by X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy and scanning electron microscopy techniques, and evaluated as electrode materials for high-performance supercapacitors by cyclic voltammetry, galvanostatic charge-discharge curves and electrochemical impedance spectroscopy. A great improvement in specific capacitance is achieved with the present hybrids, from 255 F g -1 for WO 3 nanoparticles to 580 F g -1 for Gr-WO 3 hybrids (scanned at 1 A g -1 in 2 M KOH over a potential window of 0 to 0.45 V). The Gr-WO 3 hybrid exhibits an excellent high rate capability and good cycling stability with more than 92% capacitance retention over 1000 cycles at a current density of 5 A g -1 . The enhancement in supercapacitor performance of Gr-WO 3 is not only attributed to its unique nanostructure with large specific surface area, but also its excellent electro-conductivity, which facilitates efficient charge transport and promotes electrolyte diffusion. As a whole, this work indicates that Gr-WO 3 hybrids are a promising electrode material for high-performance supercapacitors.

Ionically conducting PVA-LiClO4 gel electrolyte for high performance flexible solid state supercapacitors.

PubMed

Chodankar, Nilesh R; Dubal, Deepak P; Lokhande, Abhishek C; Lokhande, Chandrakant D

2015-12-15

The synthesis of polymer gel electrolyte having high ionic conductivity, excellent compatibility with active electrode material, mechanical tractability and long life is crucial to obtain majestic electrochemical performance for flexible solid state supercapacitors (FSS-SCs). Our present work describes effect of different polymers gel electrolytes on electrochemical properties of MnO2 based FSS-SCs device. It is revealed that, MnO2-FSS-SCs with polyvinyl alcohol (PVA)-Lithium perchlorate (LiClO4) gel electrolyte demonstrate excellent electrochemical features such as maximum operating potential window (1.2V), specific capacitance of 112Fg(-1) and energy density of 15Whkg(-1) with extended cycling stability up to 2500CV cycles. Moreover, the calendar life suggests negligible decrease in the electrochemical performance of MnO2-FSS-SCs after 20days. Copyright © 2015 Elsevier Inc. All rights reserved.

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.

Facile synthesis of ultrathin manganese dioxide nanosheets arrays on nickel foam as advanced binder-free supercapacitor electrodes

NASA Astrophysics Data System (ADS)

Huang, Ming; Zhao, Xiao Li; Li, Fei; Zhang, Li Li; Zhang, Yu Xin

2015-03-01

Ultrathin MnO2 nanosheets arrays on Ni foam have been fabricated by a facile hydrothermal approach and further investigated as the binder-free electrode for high-performance supercapacitors. This unique well-designed binder-free electrode exhibits a high specific capacitance (595.2 F g-1 at a current density of 0.5 A g-1), good rate capability (64.1% retention), and excellent cycling stability (89% capacitance retention after 3000 cycles). Moreover, an asymmetric supercapacitor is constructed using the as-prepared MnO2 nanosheets arrays as the positive electrode and activated microwave exfoliated graphite oxide (MEGO) as the negative electrode. The optimized asymmetric supercapacitor displays excellent electrochemical performance with an energy density of 25.8 Wh kg-1 and a maximum power density of 223.2 kW kg-1. These impressive performances suggest that the MnO2 nanosheet array is a promising electrode material for supercapacitors.

Silicon and Carbon Nanocomposite Spheres with Enhanced Electrochemical Performance for Full Cell Lithium Ion Batteries

PubMed Central

Wang, Wei; Favors, Zachary; Li, Changling; Liu, Chueh; Ye, Rachel; Fu, Chengyin; Bozhilov, Krassimir; Guo, Juchen; Ozkan, Mihrimah; Ozkan, Cengiz S.

2017-01-01

Herein, facile synthesis of monodisperse silicon and carbon nanocomposite spheres (MSNSs) is achieved via a simple and scalable surface-protected magnesiothermic reduction with subsequent chemical vapor deposition (CVD) process. Li-ion batteries (LIBs) were fabricated to test the utility of MSNSs as an anode material. LIB anodes based on MSNSs demonstrate a high reversible capacity of 3207 mAh g−1, superior rate performance, and excellent cycling stability. Furthermore, the performance of full cell LIBs was evaluated by using MSNS anode and a LiCoO2 cathode with practical electrode loadings. The MSNS/LiCoO2 full cell demonstrates high gravimetric energy density in the order of 850 Wh L−1 with excellent cycling stability. This work shows a proof of concept of the use of monodisperse Si and C nanocomposite spheres toward practical lithium-ion battery applications. PMID:28322285

Porous Hard Carbon Derived from Walnut Shell as an Anode Material for Sodium-Ion Batteries

NASA Astrophysics Data System (ADS)

Zhang, Sensen; Li, Ying; Li, Min

2018-02-01

Porous hard carbon with large interlayer distance was fabricated from walnut shells through a facile high-temperature pyrolysis process and investigated as an anode material for sodium-ion batteries (SIBs). The results show that the electrochemical performance is mainly dependent on the pyrolysis temperature. The porous hard carbon, which was carbonized at 1300°C, displays the highest reversible capacity of 230 mAh g-1 at 20 mA g-1 and an excellent cycling stability (96% capacity retained over 200 cycles). The promising electrochemical performances are attributed to the porous structure reducing distances for sodium ion diffusion and expanded interlayer spacing, which is beneficial for sodium reversible insertion/extraction. The excellent electrochemical performance as well as the low-cost and environmental friendliness demonstrates that walnut shell-derived porous hard carbon is a promising anode material candidate for SIBs.

H3PO4 solution hydrothermal carbonization combined with KOH activation to prepare argy wormwood-based porous carbon for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Dai, Changchao; Wan, Jiafeng; Yang, Juan; Qu, Shanshan; Jin, Tieyu; Ma, Fangwei; Shao, Jinqiu

2018-06-01

In this work, argy wormwood-based porous carbon electrode materials for high-performance supercapacitors are prepared through H3PO4 solution hydrothermal carbonization and subsequent KOH activation. The obtained carbon has a specific surface area (SSA) of 927 m2 g-1, a total pore volume of 0.56 cm3 g-1, and a high oxygen (9.38%) content. In three-electrode system, it exhibits specific capacitance of 344 F g-1 at 1 A g-1. Moreover, the symmetric supercapacitor shows an excellent rate capability of 87% retention from 1 A g-1 to 10 A g-1, and a good cycling performance with 91.6% retention over 5000 cycles in 6 M KOH. Therefore, the sample activated by H3PO4 & KOH exhibits an excellent future in energy storage.

Extremely Stable Polypyrrole Achieved via Molecular Ordering for Highly Flexible Supercapacitors.

PubMed

Huang, Yan; Zhu, Minshen; Pei, Zengxia; Huang, Yang; Geng, Huiyuan; Zhi, Chunyi

2016-01-27

The cycling stability of flexible supercapacitors with conducting polymers as electrodes is limited by the structural breakdown arising from repetitive counterion flow during charging/discharging. Supercapacitors made of facilely electropolymerized polypyrrole (e-PPy) have ultrahigh capacitance retentions of more than 97, 91, and 86% after 15000, 50000, and 100000 charging/discharging cycles, respectively, and can sustain more than 230000 charging/discharging cycles with still approximately half of the initial capacitance retained. To the best of our knowledge, such excellent long-term cycling stability was never reported. The fully controllable electropolymerization shows superiority in molecular ordering, favoring uniform stress distribution and charge transfer. Being left at ambient conditions for even 8 months, e-PPy supercapacitors completely retain the good electrochemical performance. The extremely stable supercapacitors with excellent flexibility and scalability hold considerable promise for the commerical application of flexible and wearable electronics.

Nanoscaled Na3PS4 Solid Electrolyte for All-Solid-State FeS2/Na Batteries with Ultrahigh Initial Coulombic Efficiency of 95% and Excellent Cyclic Performances.

PubMed

Wan, Hongli; Mwizerwa, Jean Pierre; Qi, Xingguo; Xu, Xiaoxiong; Li, Hong; Zhang, Qiang; Cai, Liangting; Hu, Yong-Sheng; Yao, Xiayin

2018-04-18

Nanosized Na 3 PS 4 solid electrolyte with an ionic conductivity of 8.44 × 10 -5 S cm -1 at room temperature is synthesized by a liquid-phase reaction. The resultant all-solid-state FeS 2 /Na 3 PS 4 /Na batteries show an extraordinary high initial Coulombic efficiency of 95% and demonstrate high energy density of 611 Wh kg -1 at current density of 20 mA g -1 at room temperature. The outstanding performances of the battery can be ascribed to good interface compatibility and intimate solid-solid contact at FeS 2 electrode/nanosized Na 3 PS 4 solid electrolytes interface. Meanwhile, excellent cycling stability is achieved for the battery after cycling at 60 mA g -1 for 100 cycles, showing a high capacity of 287 mAh g -1 with the capacity retention of 80%.

Low Temperature Life-cycle Testing of a Lithium-ion Battery for Low-earth-orbiting Spacecraft

NASA Technical Reports Server (NTRS)

Reid, Concha

2004-01-01

A flight-qualified, lithium-ion (Li-ion) battery developed for the Mars Surveyor Program 2001 lander is undergoing life-testing at low temperature under a low-Earth-orbit (LEO) profile to assess its capability to provide long term energy storage for aerospace missions. NASA has embarked upon an ambitious course to return humans to the moon by 2015-2020 in preparation for robotic and human exploration of Mars and robotic exploration of the moons of outer planets. Li-ion batteries are excellent candidates to provide power and energy storage for multiple aspects of these missions due to their low specific energy, low energy density, and excellent low temperature performance. Laboratory testing of Li-ion technology is necessary in order to assess lifetime, characterize multi-cell battery-level performance under aerospace conditions, and to gauge safety aspects of the technology. Life-cycle testing provides an opportunity to examine battery-level performance and the dynamics of individual cells in the stack over the entire life of the battery. Data generated through this testing will be critical to establish confidence in the technology for its widespread use in manned and unmanned mission. This paper discusses the performance of the 28 volt, 25 ampere-hour battery through 6000 LEO cycles, which corresponds to one year on LEO orbit. Testing is being performed at 0 C and 40% depth-of-discharge. Individual cell behaviors and their effect on the performance of the battery are described. Capacity, impedance, energy efficiency and end-of-discharge voltage at 1000 cycle intervals are reported. Results from this life-testing will help contribute to the database on battery-level performance of aerospace Li-ion batteries and low temperature cycling under LEO conditions.

Novel peapoded Li4Ti5O12 nanoparticles for high-rate and ultralong-life rechargeable lithium ion batteries at room and lower temperatures

NASA Astrophysics Data System (ADS)

Peng, Liang; Zhang, Huijuan; Fang, Ling; Zhang, Yan; Wang, Yu

2016-01-01

In this paper, a novel peapod-like Li4Ti5O12-C composite architecture with high conductivity is firstly designed and synthesized to be used as anode materials for lithium-ion batteries. In the synthesis, Na2Ti3O7 nanotubes act as precursors and sacrificial templates, and glucose molecules serve as the green carbon source, thus the peapod-like Li4Ti5O12-C composite can be fabricated by a facile hydrothermal reaction and the subsequent solid-state process. Compared to the previous reports, the as-prepared samples obtained by our new strategy exhibit excellent electrochemical performances, such as outstanding rate capability (an extremely reversible capability of 148 mA h g-1, 125 mA h g-1 at 30 C and 90 C, respectively) as well as excellent cycling performance (about 5% capacity loss after 5000 cycles at 10 C with 152 mA h g-1 capacity retained). The low-temperature measurements also demonstrate that the electrochemical performances of the peapod-like Li4Ti5O12-C composite are remarkably improved at various rate currents (at the low-temperature of -25 °C, a high Coulombic efficiency of about 99% can be achieved after 500 cycles at 10 C).In this paper, a novel peapod-like Li4Ti5O12-C composite architecture with high conductivity is firstly designed and synthesized to be used as anode materials for lithium-ion batteries. In the synthesis, Na2Ti3O7 nanotubes act as precursors and sacrificial templates, and glucose molecules serve as the green carbon source, thus the peapod-like Li4Ti5O12-C composite can be fabricated by a facile hydrothermal reaction and the subsequent solid-state process. Compared to the previous reports, the as-prepared samples obtained by our new strategy exhibit excellent electrochemical performances, such as outstanding rate capability (an extremely reversible capability of 148 mA h g-1, 125 mA h g-1 at 30 C and 90 C, respectively) as well as excellent cycling performance (about 5% capacity loss after 5000 cycles at 10 C with 152 mA h g-1 capacity retained). The low-temperature measurements also demonstrate that the electrochemical performances of the peapod-like Li4Ti5O12-C composite are remarkably improved at various rate currents (at the low-temperature of -25 °C, a high Coulombic efficiency of about 99% can be achieved after 500 cycles at 10 C). Electronic supplementary information (ESI) available: More SEM, EDS, TEM, and XPS data are available. See DOI: 10.1039/c5nr08399k

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.

Multi-channel and porous SiO@N-doped C rods as anodes for high-performance lithium-ion batteries

NASA Astrophysics Data System (ADS)

Huang, Xiao; Li, Mingqi

2018-05-01

To improve the cycling stability and rate capability of SiO electrodes, multi-channel and porous SiO@N-doped C (mp-SiO@N-doped C) rods are fabricated by the combination of electrospinning and heat treatment with the assistance of poly(methyl methacrylate) (PMMA). During annealing, in-situ PMMA degradation and gasification lead to the formation of multi-channel structure and more pores. As anodes for lithium ion batteries, the mp-SiO@N-doped C rods exhibit excellent cycling stability. At a current density of 400 mA g-1, a discharge capacity of 806 mAh g-1 can be kept after 250 cycles, the retention of which is over than 100% versus the initial reversible capacity. Compared with the SiO@N-doped C rods synthesized without the help of PMMA, the mp-SiO@N-doped C rods exhibit more excellent rate capability. The excellent electrochemical performance is attributed to the special structure of the mp-SiO@N-doped C rods. In addition to the conductivity improved by carbon fibers, the multi-channel and porous structures not only make ions/electrons transfer and electrolyte diffusion easier, but also contribute to the structural stability of the electrodes.

Self-supported Zn3P2 nanowire arrays grafted on carbon fabrics as an advanced integrated anode for flexible lithium ion batteries

NASA Astrophysics Data System (ADS)

Li, Wenwu; Gan, Lin; Guo, Kai; Ke, Linbo; Wei, Yaqing; Li, Huiqiao; Shen, Guozhen; Zhai, Tianyou

2016-04-01

We, for the first time, successfully grafted well-aligned binary lithium-reactive zinc phosphide (Zn3P2) nanowire arrays on carbon fabric cloth by a facile CVD method. When applied as a novel self-supported binder-free anode for lithium ion batteries (LIBs), the hierarchical three-dimensional (3D) integrated anode shows excellent electrochemical performances: a highly reversible initial lithium storage capacity of ca. 1200 mA h g-1 with a coulombic efficiency of up to 88%, a long lifespan of over 200 cycles without obvious decay, and a high rate capability of ca. 400 mA h g-1 capacity retention at an ultrahigh rate of 15 A g-1. More interestingly, a flexible LIB full cell is assembled based on the as-synthesized integrated anode and the commercial LiFePO4 cathode, and shows striking lithium storage performances very close to the half cells: a large reversible capacity over 1000 mA h g-1, a long cycle life of over 200 cycles without obvious decay, and an ultrahigh rate performance of ca. 300 mA h g-1 even at 20 A g-1. Considering the excellent lithium storage performances of coin-type half cells as well as flexible full cells, the as-prepared carbon cloth grafted well-aligned Zn3P2 nanowire arrays would be a promising integrated anode for flexible LIB full cell devices.We, for the first time, successfully grafted well-aligned binary lithium-reactive zinc phosphide (Zn3P2) nanowire arrays on carbon fabric cloth by a facile CVD method. When applied as a novel self-supported binder-free anode for lithium ion batteries (LIBs), the hierarchical three-dimensional (3D) integrated anode shows excellent electrochemical performances: a highly reversible initial lithium storage capacity of ca. 1200 mA h g-1 with a coulombic efficiency of up to 88%, a long lifespan of over 200 cycles without obvious decay, and a high rate capability of ca. 400 mA h g-1 capacity retention at an ultrahigh rate of 15 A g-1. More interestingly, a flexible LIB full cell is assembled based on the as-synthesized integrated anode and the commercial LiFePO4 cathode, and shows striking lithium storage performances very close to the half cells: a large reversible capacity over 1000 mA h g-1, a long cycle life of over 200 cycles without obvious decay, and an ultrahigh rate performance of ca. 300 mA h g-1 even at 20 A g-1. Considering the excellent lithium storage performances of coin-type half cells as well as flexible full cells, the as-prepared carbon cloth grafted well-aligned Zn3P2 nanowire arrays would be a promising integrated anode for flexible LIB full cell devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08467a

Enhanced performance of HRGO-RuO 2 solid state flexible supercapacitors fabricated by electrophoretic deposition

DOE PAGES

Amir, Fatima Z.; Pham, V. H.; Mullinax, D. W.; ...

2016-06-07

Ruthenium oxide (RuO 2) nanomaterials exist as excellent materials for electrochemical capacitors. However, they tend to suffer from low mechanical flexibility when cast into films, which makes them unsuitable for flexible device applications. Herein, we report an environmentally friendly and solution-processable approach to fabricate RuO 2-based composite electrodes for flexible solid state supercapacitors. The composites were produced by anchoring RuO 2 nanoparticles onto holey reduced graphene oxide (HRGO) via a sol-gel method, followed by the electrophoretic deposition (EPD) of the material into thin films. The uniform anchoring of ultra-small RuO 2 nanoparticles on the two-dimensional HRGO sheets resulted in HRGO-RuOmore » 2 hybrid sheets with excellent mechanical flexibility of HRGO. EPD induced a layer-by-layer assembly mechanism for the HRGO-RuO 2 hybrid sheets, which resulted in a binder-free, flexible electrode. The obtained HRGO-RuO 2 flexible supercapacitors exhibited excellent electrochemical capacitive performance in a PVA-H 2SO 4 gel electrolyte with a specific capacitance of 418 F g -1 and superior cycling stability of 88.5% capacitance retention after 10,000 cycles. Additionally, these supercapacitors exhibited high rate performance with capacitance retention of 85% by increasing the current density from 1.0 to 20.0 Ag -1, and excellent mechanical flexibility with only 4.9% decay in the performance when bent 180°.« less

Hierarchically porous nitrogen-doped carbon derived from the activation of agriculture waste by potassium hydroxide and urea for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Zou, Kaixiang; Deng, Yuanfu; Chen, Juping; Qian, Yunqian; Yang, Yuewang; Li, Yingwei; Chen, Guohua

2018-02-01

Nitrogen-doped carbon with an ultra-high specific surface area and a hierarchically interconnected porous structure is synthesized in large scale from a green route, that is, the activation of bagasse via a one-step method using KOH and urea. KOH and urea play a synergistic effect for the enhancement of the specific surface area and the modification of pore size of the as-prepared material. Benefiting from the multiple synergistic roles originated from an ultra-high specific area (2905.4 m2 g-1), a high porous volume (2.05 mL g-1 with 75.6 vol% micropores, which is an ideal proportion of micropores for obtaining high specific capacitance), a suitable nitrogen content (2.63 wt%), and partial graphitization, the hierarchically interconnected porous N-doped carbon exhibits an excellent electrochemical performance with a high specific capacitance (350.8, 301.9, and 259.5 F g-1 at 1.0 A g-1 in acidic, alkaline, and neutral electrolytes, respectively), superior rate capability and excellent cycling stability (almost no capacitance loss up to 5000 cycles). Furthermore, the symmetric device assembled by this material achieves high energy densities of 39.1 and 23.5 Wh kg-1 at power densities of 1.0 and 20 kW kg-1, respectively, and exhibits an excellent long-term cycling stability (with capacitance retention above 95.0% after 10 000 cycles).

Fabrication of hollow nanorod electrodes based on RuO2//Fe2O3 for an asymmetric supercapacitor.

PubMed

Wang, Qiufan; Liang, Xiao; Ma, Yun; Zhang, Daohong

2018-06-12

In this work, hollow RuO2 nanotube arrays were successfully grown on carbon cloth by using a facile two-step method to fabricate a binder-free electrode. The well-aligned electrode displays excellent electrochemical performance. By using RuO2 hollow nanotube arrays as the positive electrode and Fe2O3 as the negative electrode, a flexible solid-state asymmetric supercapacitor (ASC) has been fabricated which exhibited excellent electrochemical performance, such as a high capacitance of 4.9 F cm-3, a high energy density of 1.5 mW h cm-3 and a high power density of 9.1 mW cm-3. In addition, the two-electrode SC shows high cycling stability with 97% capacitance retention after 5000 charge-discharge cycles. These excellent electrochemical performances are ascribed to the unique hollow structural design of electrodes, which can shorten the ion diffusion length, provide a fast ion transport channel, and offer a large electrode/electrolyte interface for the charge-transfer reaction. The structural design and the synthesis approach are general and can be extended to synthesizing a broad range of materials systems.

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).

Carbon with Expanded and Well-Developed Graphene Planes Derived Directly from Condensed Lignin as a High-Performance Anode for Sodium-Ion Batteries.

PubMed

Yoon, Dohyeon; Hwang, Jieun; Chang, Wonyoung; Kim, Jaehoon

2018-01-10

In this study, we demonstrate that lignin, which constitutes 30-40 wt % of the terrestrial lignocellulosic biomass and is produced from second generation biofuel plants as a cheap byproduct, is an excellent precursor material for sodium-ion battery (NIB) anodes. Because it is rich in aromatic monomers that are highly cross-linked by ether and condensed bonds, the lignin material carbonized at 1300 °C (C-1300) in this study has small graphitic domains with well-developed graphene layers, a large interlayer spacing (0.403 nm), and a high micropore surface area (207.5 m 2 g -1 ). When tested as an anode in an NIB, C-1300 exhibited an initial Coulombic efficiency of 68% and a high reversible capacity of 297 mA h g -1 at 50 mA g -1 after 50 cycles. The high capacity of 199 mA h g -1 at less than 0.1 V with a flat voltage profile and an extremely low charge-discharge voltage hysteresis (<0.03 V) make C-1300 a promising energy-dense electrode material. In addition, C-1300 exhibited an excellent high-rate performance of 116 mA h g -1 at 2.5 A g -1 and showed stable cycling retention (0.2% capacity decay per cycle after 500 cycles). By comparing the properties of the lignin-derived carbon with oak sawdust-derived and sugar-derived carbons and a low-temperature carbonized sample (900 °C), the reasons for the excellent performance of C-1300 were determined to result from facilitated Na + -ion transport to the graphitic layer and the microporous regions that penetrate through the less defective and enlarged interlayer spacings.

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.

Hierarchical Mesoporous/Macroporous Perovskite La0.5Sr0.5CoO3-x Nanotubes: A Bifunctional Catalyst with Enhanced Activity and Cycle Stability for Rechargeable Lithium Oxygen Batteries.

PubMed

Liu, Guoxue; Chen, Hongbin; Xia, Lu; Wang, Suqing; Ding, Liang-Xin; Li, Dongdong; Xiao, Kang; Dai, Sheng; Wang, Haihui

2015-10-14

Perovskites show excellent specific catalytic activity toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline solutions; however, small surface areas of the perovskites synthesized by traditional sol-gel methods lead to low utilization of catalytic sites, which gives rise to poor Li-O2 batteries performance and restricts their application. Herein, a hierarchical mesporous/macroporous perovskite La0.5Sr0.5CoO3-x (HPN-LSC) nanotube is developed to promote its application in Li-O2 batteries. The HPN-LSC nanotubes were synthesized via electrospinning technique followed by postannealing. The as-prepared HPN-LSC catalyst exhibits outstanding intrinsic ORR and OER catalytic activity. The HPN-LSC/KB electrode displays excellent performance toward both discharge and charge processes for Li-O2 batteries, which enhances the reversibility, the round-trip efficiency, and the capacity of resultant batteries. The synergy of high catalytic activity and hierarchical mesoporous/macroporous nanotubular structure results in the Li-O2 batteries with good rate capability and excellent cycle stability of sustaining 50 cycles at a current density of 0.1 mA cm(-2) with an upper-limit capacity of 500 mAh g(-1). The results will benefit for the future development of high-performance Li-O2 batteries using hierarchical mesoporous/macroporous nanostructured perovskite-type catalysts.

A high performance quasi-solid-state supercapacitor based on CuMnO2 nanoparticles

NASA Astrophysics Data System (ADS)

Wang, Lu; Arif, Muhammad; Duan, Guorong; Chen, Shenming; Liu, Xiaoheng

2017-07-01

Mixed metal or transition metal oxides hold an unveiled potential as one of the most promising energy storage material because of their excellent stability, reliable conductivity, and convenient use. In this work, CuMnO2 nanoparticles are successfully prepared by a facile hydrothermal process with the help of dispersing agent cetyltrimethylammonium bromide (CTAB). CuMnO2 nanoparticles possess a uniform quadrilateral shape, small size (approximately 25 × 25 nm-35 × 35 nm), excellent dispersity, and large specific surface specific (56.9 m2 g-1) with an interparticle mesoporous structure. All these characteristics can bring benefit for their application in supercapacitor. A quasi-solid-state symmetric supercapacitor device is assembled by using CuMnO2 nanoparticles as both positive electrode and negative electrode. The device exhibits good supercapacitive performance with a high specific capacitance (272 F g-1), a maximum power density of 7.56 kW kg-1 and a superior cycling stability of 18,000 continuous cycles, indicating an excellent potential to be used in energy storage device.

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

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.

Inherent N,O-containing carbon frameworks as electrode materials for high-performance supercapacitors.

PubMed

Hu, Fangyuan; Wang, Jinyan; Hu, Shui; Li, Linfei; Wang, Gang; Qiu, Jieshan; Jian, Xigao

2016-09-15

N,O-Containing micropore-dominated materials have been developed successfully via temperature-dependent cross-linking of 4,4'-(dioxo-diphenyl-2,3,6,7-tetraazaanthracenediyl)dibenzonitrile (DPDN) monomers. By employing a molecular engineering strategy, we have designed and synthesized a series of porous heteroatom-containing carbon frameworks (PHCFs), in which nitrogen and oxygen heteroatoms are distributed homogeneously throughout the whole framework at the atomic level, which can ensure the stability of its electrical properties. The as-made PHCFs@550 exhibits a high specific capacitance of 378 F g -1 , with an excellent long cycling life, including excellent cycling stability (capacitance retention of ca. 120% over 20 000 cycles). Moreover, the successful preparation of PHCFs provides new insights for the fabrication of nitrogen and oxygen-containing electrode materials from readily available components via a facile route.

Interconnected 3 D Network of Graphene-Oxide Nanosheets Decorated with Carbon Dots for High-Performance Supercapacitors.

PubMed

Zhao, Xiao; Li, Ming; Dong, Hanwu; Liu, Yingliang; Hu, Hang; Cai, Yijin; Liang, Yeru; Xiao, Yong; Zheng, Mingtao

2017-06-22

Interconnected 3 D nanosheet networks of reduced graphene oxide decorated with carbon dots (rGO/CDs) are successfully fabricated through a simple one-pot hydrothermal process. The as-prepared rGO/CDs present appropriate 3 D interconnectivity and abundant stable oxygen-containing functional groups, to which we can attribute the excellent electrochemical performance such as high specific capacitance, good rate capability, and great cycling stability. Employed as binder-free electrodes for supercapacitors, the resulting rGO/CDs exhibit excellent long-term cycling stability (ca. 92 % capacitance retention after 20 000 charge/discharge cycles at current density of 10 A g -1 ) as well as a maximum specific capacitance of about 308 F g -1 at current density of 0.5 A g -1 , which is much higher than that of rGO (200 F g -1 ) and CDs (2.2 F g -1 ). This work provides a promising strategy to fabricate graphene-based nanomaterials with greatly boosted electrochemical performances by decoration of with CDs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flexible Supercapacitors Based on Polyaniline Arrays Coated Graphene Aerogel Electrodes

NASA Astrophysics Data System (ADS)

Yang, Yu; Xi, Yunlong; Li, Junzhi; Wei, Guodong; Klyui, N. I.; Han, Wei

2017-06-01

Flexible supercapacitors(SCs) made by reduced graphene oxide (rGO)-based aerogel usually suffer from the low energy density, short cycle life and bad flexibility. In this study, a new, synthetic strategy was developed for enhancing the electrochemical performances of rGO aerogel-based supercapacitor via electrodeposition polyaniline arrays on the prepared ultralight rGO aerogel. The novel hybrid composites with coated polyaniline (PANI) arrays growing on the rGO surface can take full advantage of the rich open-pore and excellent conductivity of the crosslinking framework structure of 3D rGO aerogel and high capacitance contribution from the PANI. The obtained hybrid composites exhibit excellent electrochemical performance with a specific capacitance of 432 F g-1 at the current density of 1 A g-1, robust cycling stability to maintain 85% after 10,000 charge/discharge cycles and high energy density of 25 W h kg-1. Furthermore, the flexible all-solid-state supercapacitor have superior flexibility and outstanding stability under different bending states from the straight state to the 90° status. The high-performance flexible all-solid-state SCs together with the lighting tests demonstrate it possible for applications in portable electronics.

Three-Dimensional NiCo2O4@Polypyrrole Coaxial Nanowire Arrays on Carbon Textiles for High-Performance Flexible Asymmetric Solid-State Supercapacitor.

PubMed

Kong, Dezhi; Ren, Weina; Cheng, Chuanwei; Wang, Ye; Huang, Zhixiang; Yang, Hui Ying

2015-09-30

In this article, we report a novel electrode of NiCo2O4 nanowire arrays (NWAs) on carbon textiles with a polypyrrole (PPy) nanosphere shell layer to enhance the pseudocapacitive performance. The merits of highly conductive PPy and short ion transport channels in ordered NiCo2O4 mesoporous nanowire arrays together with the synergistic effect between NiCo2O4 and PPy result in a high specific capacitance of 2244 F g(-1), excellent rate capability, and cycling stability in NiCo2O4/PPy electrode. Moreover, a lightweight and flexible asymmetric supercapacitor (ASC) device is successfully assembled using the hybrid NiCo2O4@PPy NWAs and activated carbon (AC) as electrodes, achieving high energy density (58.8 W h kg(-1) at 365 W kg(-1)), outstanding power density (10.2 kW kg(-1) at 28.4 W h kg(-1)) and excellent cycling stability (∼89.2% retention after 5000 cycles), as well as high flexibility. The three-dimensional coaxial architecture design opens up new opportunities to fabricate a high-performance flexible supercapacitor for future portable and wearable electronic devices.

Flexible Supercapacitors Based on Polyaniline Arrays Coated Graphene Aerogel Electrodes.

PubMed

Yang, Yu; Xi, Yunlong; Li, Junzhi; Wei, Guodong; Klyui, N I; Han, Wei

2017-12-01

Flexible supercapacitors(SCs) made by reduced graphene oxide (rGO)-based aerogel usually suffer from the low energy density, short cycle life and bad flexibility. In this study, a new, synthetic strategy was developed for enhancing the electrochemical performances of rGO aerogel-based supercapacitor via electrodeposition polyaniline arrays on the prepared ultralight rGO aerogel. The novel hybrid composites with coated polyaniline (PANI) arrays growing on the rGO surface can take full advantage of the rich open-pore and excellent conductivity of the crosslinking framework structure of 3D rGO aerogel and high capacitance contribution from the PANI. The obtained hybrid composites exhibit excellent electrochemical performance with a specific capacitance of 432 F g -1 at the current density of 1 A g -1 , robust cycling stability to maintain 85% after 10,000 charge/discharge cycles and high energy density of 25 W h kg -1 . Furthermore, the flexible all-solid-state supercapacitor have superior flexibility and outstanding stability under different bending states from the straight state to the 90° status. The high-performance flexible all-solid-state SCs together with the lighting tests demonstrate it possible for applications in portable electronics.

Toward understanding the lithiation/delithiation process in Fe 0.5TiOPO 4/C electrode material for lithium-ion batteries

DOE PAGES

Lasri, Karima; Mahmoud, Abdelfattah; Saadoune, Ismael; ...

2015-11-28

We used Fe 0.5TiOPO 4/C composite as anode material for LIB and exhibits excellent cycling performance when the electrode is cycled in two different voltage ranges [3.0-1.3V] and [3.0- 0.02V] where different insertion mechanisms were involved. Based on in situ X-ray diffraction, in situ XANES spectroscopy results, and various electrochemical analyses at high and low voltage cut-off, we found that Fe 0.5TiOPO 4/C electrode materials still maintains its structure crystallinity after cycling between [3.0-1.3V] showing formation of new phase at the end of first discharge, with a reversible capacity of 100 mAhg-1 after 50 cycles at C/5 rate. Moreover, atmore » highly lithiated states, [3.0-0.02V] voltage range, a reduction decomposition reaction highlights the Li-insertion/extraction behaviors, and low phase crystallinity is observed during cycling, in addition an excellent rate behavior and a reversible capacity of 250 mAhg - 1 can still be maintained after 50 cycles at high cycling rate 5C.« less

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.

Bacterial cellulose-based sheet-like carbon aerogels for the in situ growth of nickel sulfide as high performance electrode materials for asymmetric supercapacitors.

PubMed

Zuo, Lizeng; Fan, Wei; Zhang, Youfang; Huang, Yunpeng; Gao, Wei; Liu, Tianxi

2017-03-30

Electroactive materials, such as nickel sulfide (NiS), with high theoretical capacities have attracted broad interest to fabricate highly efficient supercapacitors. Preventing aggregation and increasing the conductivity of NiS particles are key challenging tasks to fully achieve excellent electrochemical properties of NiS. One effective approach to solve these problems is to combine NiS with highly porous and conductive carbon materials such as carbon aerogels. In this study, a green and facile method for the in situ growth of NiS particles on bacterial cellulose (BC)-derived sheet-like carbon aerogels (CAs) has been reported. CA prepared by the dissolution-gelation-carbonization process was used as a framework to construct NiS/CA composite aerogels with NiS uniformly decorated on the pore walls of CA. It was found that the NiS/CA composite aerogel electrodes exhibit excellent capacitive performance with high specific capacitance (1606 F g -1 ), good rate capacitance retention (69% at 10 A g -1 ), and enhanced cycling stability (91.2% retention after 10 000 continuous cyclic voltammetry cycles at 100 mV s -1 ). Furthermore, asymmetric supercapacitors (ASCs) were constructed utilizing NiS/CA composite and CA as the positive and negative electrode materials, respectively. Through the synergistic effect of three-dimensional porous structures and conductive networks derived from CA and the high capacitive performance offered by NiS, the ASC device exhibited an energy density of ∼21.5 Wh kg -1 and a power density of 700 W kg -1 at the working voltage of 1.4 V in 2 M KOH aqueous solution. The ASC device also showed excellent long-term cycle stability with ∼87.1% specific capacitance retention after 10 000 cycles of cyclic voltammetry scans. Therefore, the NiS/CA composite shows great potential as a promising alternative to high-performance electrode materials for supercapacitors.

High-Columbic-Efficiency Lithium Battery Based on Silicon Particle Materials.

PubMed

Zhang, Junying; Zhang, Chunqian; Wu, Shouming; Zhang, Xu; Li, Chuanbo; Xue, Chunlai; Cheng, Buwen

2015-12-01

Micro-sized polycrystalline silicon particles were used as anode materials of lithium-ion battery. The columbic efficiency of the first cycle reached a relatively high value of 91.8 % after prelithiation and increased to 99 % in the second cycle. Furthermore, columbic efficiency remained above 99 % for up to 280+ cycles. The excellent performances of the batteries were the results of the use of a proper binder to protect the electrode from cracking and the application of a suitable conductive agent to provide an efficient conductive channel. The good performance was also significantly attributed to the electrolyte in the packaging process.

A room-temperature sodium rechargeable battery using an SO2-based nonflammable inorganic liquid catholyte

PubMed Central

Jeong, Goojin; Kim, Hansu; Sug Lee, Hyo; Han, Young-Kyu; Hwan Park, Jong; Hwan Jeon, Jae; Song, Juhye; Lee, Keonjoon; Yim, Taeeun; Jae Kim, Ki; Lee, Hyukjae; Kim, Young-Jun; Sohn, Hun-Joon

2015-01-01

Sodium rechargeable batteries can be excellent alternatives to replace lithium rechargeable ones because of the high abundance and low cost of sodium; however, there is a need to further improve the battery performance, cost-effectiveness, and safety for practical use. Here we demonstrate a new type of room-temperature and high-energy density sodium rechargeable battery using an SO2-based inorganic molten complex catholyte, which showed a discharge capacity of 153 mAh g−1 based on the mass of catholyte and carbon electrode with an operating voltage of 3 V, good rate capability and excellent cycle performance over 300 cycles. In particular, non-flammability and intrinsic self-regeneration mechanism of the inorganic liquid electrolyte presented here can accelerate the realization of commercialized Na rechargeable battery system with outstanding reliability. Given that high performance and unique properties of Na–SO2 rechargeable battery, it can be another promising candidate for next generation energy storage system. PMID:26243052

A hierarchical nanostructure consisting of amorphous MnO 2, Mn 3O 4 nanocrystallites, and single-crystalline MnOOH nanowires for supercapacitors

NASA Astrophysics Data System (ADS)

Hu, Chi-Chang; Hung, Ching-Yun; Chang, Kuo-Hsin; Yang, Yi-Lin

In this communication, a porous hierarchical nanostructure consisting of amorphous MnO 2 (a-MnO 2), Mn 3O 4 nanocrystals, and single-crystalline MnOOH nanowires is designed for the supercapacitor application, which is prepared by a simple two-step electrochemical deposition process. Because of the gradual co-transformation of Mn 3O 4 nanocrystals and a-MnO 2 nanorods into an amorphous manganese oxide, the cycle stability of a-MnO 2 is obviously enhanced by adding Mn 3O 4. This unique ternary oxide nanocomposite with 100-cycle CV activation exhibits excellent capacitive performances, i.e., excellent reversibility, high specific capacitances (470 F g -1 in CaCl 2), high power property, and outstanding cycle stability. The highly porous microstructures of this composite before and after the 10,000-cycle CV test are examined by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Direct Electrophoretic Deposition of Binder-Free Co3O4/Graphene Sandwich-Like Hybrid Electrode as Remarkable Lithium Ion Battery Anode.

PubMed

Yang, Yang; Huang, Jingxin; Zeng, Jing; Xiong, Jian; Zhao, Jinbao

2017-09-27

Co 3 O 4 is emerging as a promising anode candidate for lithium ion batteries (LIBs) with high theoretical capacity (890 mAh g -1 ) but suffers from poor electrochemical cycling stability resulting from the inferior intrinsic electronic conductivity and large volume changes during electrochemical cycling. Here, a new electrophoretic deposition Co 3 O 4 /graphene (EPD Co 3 O 4 /G) hybrid electrode is developed to improve the electrochemical performance. Through EPD, Co 3 O 4 nanocubes can be homogeneously embedded between graphene sheets to form a sandwich-like structure. Owing to the excellent flexibility of graphene and a large number of voids in this sandwich-like structure, the structural integrity and unobstructed conductive network can be maintained during cycling. Moreover, the electrode kinetics has proved to be a fast surface-controlled lithium storage process. As a result, the Co 3 O 4 /G hybrid electrode exhibits high specific capacity and excellent electrochemical cycling performance. The Co 3 O 4 /G hybrid electrode was also further studied by in situ electrochemical XRD to understand the relationship of its structure and performance: (1) The observed Li x Co 3 O 4 indicates an intermediate of possible small volume change in the first discharging. (2) The theoretical capacity achievement of the Co 3 O 4 in hybrid electrode was evidenced. (3) The correlation between the electrochemical performance and the structural evolution of the Co 3 O 4 /G hybrid electrode was discussed detailedly.

Polyaniline nanowire array encapsulated in titania nanotubes as a superior electrode for supercapacitors

NASA Astrophysics Data System (ADS)

Xie, Keyu; Li, Jie; Lai, Yanqing; Zhang, Zhi'an; Liu, Yexiang; Zhang, Guoge; Huang, Haitao

2011-05-01

Conducting polymer with 1D nanostructure exhibits excellent electrochemical performances but a poor cyclability that limits its use in supercapacitors. In this work, a novel composite electrode made of polyaniline nanowire-titania nanotube array was synthesized via a simple and inexpensive electrochemical route by electropolymerizing aniline onto an anodized titania nanotube array. The specific capacitance was as high as 732 F g-1 at 1 A g-1, which remained at 543 F g-1 when the current density was increased by 20 times. 74% of the maximum energy density (36.6 Wh kg-1) was maintained even at a high power density of 6000 W kg-1. An excellent long cycle life of the electrode was observed with a retention of ~86% of the initial specific capacitance after 2000 cycles. The good electrochemical performance was attributed to the unique microstructure of the electrode with disordered PANI nanowire arrays encapsulated inside the TiO2 nanotubes, providing high surface area, fast diffusion path for ions and long-term cycle stability. Such a nanocomposite electrode is attractive for supercapacitor applications.

Three-dimensional porous carbon composites containing high sulfur nanoparticle content for high-performance lithium–sulfur batteries

PubMed Central

Li, Guoxing; Sun, Jinhua; Hou, Wenpeng; Jiang, Shidong; Huang, Yong; Geng, Jianxin

2016-01-01

Sulfur is a promising cathode material for lithium–sulfur batteries because of its high theoretical capacity (1,675 mA h g−1); however, its low electrical conductivity and the instability of sulfur-based electrodes limit its practical application. Here we report a facile in situ method for preparing three-dimensional porous graphitic carbon composites containing sulfur nanoparticles (3D S@PGC). With this strategy, the sulfur content of the composites can be tuned to a high level (up to 90 wt%). Because of the high sulfur content, the nanoscale distribution of the sulfur particles, and the covalent bonding between the sulfur and the PGC, the developed 3D S@PGC cathodes exhibit excellent performance, with a high sulfur utilization, high specific capacity (1,382, 1,242 and 1,115 mA h g−1 at 0.5, 1 and 2 C, respectively), long cycling life (small capacity decay of 0.039% per cycle over 1,000 cycles at 2 C) and excellent rate capability at a high charge/discharge current. PMID:26830732

Synthesis of chitin nanofibers, MWCNTs and MnO2 nanoflakes 3D porous network flexible gel-film for high supercapacitive performance electrodes

NASA Astrophysics Data System (ADS)

Liu, Shengnan; Li, Dagang

2017-03-01

As the porous structure and conductivity result in improvement of electrochemical properties, the chitin nanofibers (ChNFs), multi-walled carbon nanotubes (MWCNTs) and MnO2 (manganese dioxide) nanoflakes 3D porous network core-shell structure gel-film was fabricated for flexible free-standing supercapacitor electrodes. The electrodes were characterized by various techniques and the results demonstrate that the as-synthesized ChNFs/MWCNTs/MnO2 gel-film electrodes exhibits excellent supercapacitive behaviours. The ChNFs/MWCNTs/MnO2 gel-film electrode shows a high capacitance of 295.2 mF/cm2 at 0.1 mA/cm2 in 1 M Na2SO4 aqueous electrolyte because of its 3D porous structure. Furthermore, the electrodes also showed surprising cycling stability for 5000 cycles with retention rate up to 157.14% at 1 mA/cm2. The data presents great promise in the application of high-performance flexible supercapacitors with the low cost, light-weight and excellent cycling ability.

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

Na2.5Fe1.75(SO4)3/Ketjen/rGO: An advanced cathode composite for sodium ion batteries

NASA Astrophysics Data System (ADS)

Goñi, A.; Iturrondobeitia, A.; Gil de Muro, I.; Lezama, L.; Rojo, T.

2017-11-01

An advanced cathode composite Na2.5Fe1.75(SO4)3/Ketjen/rGO for sodium ion batteries has been prepared, joining together the excellent electrochemical properties of the three components: off stoichiometric iron sulfate alluaudite, Ketjen Black carbon and reduced graphene oxide (rGO). This electrode material has been exhaustively characterized by XRD, thermogravimetric analysis, Raman spectroscopy and SEM and TEM microscopy. The study has demonstrated that a high quality electrode material has been designed containing a porous sulfate core properly coated by interweaved rGO fibers and Ketjen Black nanoparticles. The electrochemical study has revealed an excellent performance providing specific capacities close to the theoretical one at 1C. Additionally, this composite has shown a very good rate capability and a great cycling stability for at least 200 cycles maintaining a coulombic efficiency of 96%. The post mortem analysis, which includes EPR and XPS measurements, has demonstrated that the carbonaceous coating on the composite generates a stable and protective SEI layer over the active material guaranteeing a successful performance during a long cycle life.

Electrospun single crystalline fork-like K2V8O21 as high-performance cathode materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Hao, Pengfei; Zhu, Ting; Su, Qiong; Lin, Jiande; Cui, Rong; Cao, Xinxin; Wang, Yaping; Pan, Anqiang

2018-06-01

Single crystalline fork-like potassium vanadate (K2V8O21) has been successfully prepared through electrospinning combined with a subsequent annealing process. The as-obtained K2V8O21 forks show a unique layer-by-layer stacked structure with conductive carbon. When used as cathode materials for lithium-ion batteries, the as-prepared fork-like materials exhibit high specific discharge capacity and excellent cyclic stability. High specific discharge capacity of 200.2 mA h g-1 and 131.5 mA h g-1 can be delivered at the current densities of 50 mA g-1 and 500 mA g-1, respectively. Furthermore, the K2V8O21 electrodes exhibit excellent long-term cycling stability that maintain a capacity of 108.3 mA h g-1 after 300 cycles at 500 mA g-1 with a fading rate of only 0.054% per cycle, revealing their potential applications in next generation high-performance lithium-ion batteries.

Commercial expanded graphite as a low-cost, long-cycling life anode for potassium-ion batteries with conventional carbonate electrolyte

NASA Astrophysics Data System (ADS)

An, Yongling; Fei, Huifang; Zeng, Guifang; Ci, Lijie; Xi, Baojuan; Xiong, Shenglin; Feng, Jinkui

2018-02-01

Design and synthesis of capable anode materials that can store the large size K+ is the key of development for potassium-ion batteries. The low-cost and commercial expanded graphite with large particles is a graphite-derived material with good conductivity and enlarged interlayer spaces to boost the potassium ion diffusion coefficient during charge/discharge process. Thus, we achieve excellent anode performance for potassium-ion batteries based on an expanded graphite. It can deliver a capacity of 263 mAh g-1 at the rate of 10 mA g-1 and the reversible capacity remains almost unchanged after 500 cycles at a high rate of 200 mA g-1 with a coulombic efficiency of around 100%. The potassium storage mechanism is investigated by the ex situ XRD technique. This excellent potassium storage performance will make the expanded graphite promising anode candidate for potassium ion batteries.

Porous CrN thin films by selectively etching CrCuN for symmetric supercapacitors

NASA Astrophysics Data System (ADS)

Wei, Binbin; Mei, Gui; Liang, Hanfeng; Qi, Zhengbing; Zhang, Dongfang; Shen, Hao; Wang, Zhoucheng

2018-05-01

Transition metal nitrides are regarded as a new class of excellent electrode materials for high-performance supercapacitors due to their superior chemical stability and excellent electrical conductivity. We synthesize successfully the porous CrN thin films for binder-free supercapacitor electrodes by reactive magnetron co-sputtering and selective chemical etching. The porous CrN thin film electrodes exhibit high-capacitance performance (31.3 mF cm-2 at 1.0 mA cm-2) and reasonable cycling stability (94% retention after 20000 cycles). Moreover, the specific capacitance is more than two-fold higher than that of the CrN thin film electrodes in previous work. In addition, a symmetric supercapacitor device with a maximum energy density of 14.4 mWh cm-3 and a maximum power density of 6.6 W cm-3 is achieved. These findings demonstrate that the porous CrN thin films will have potential applications in supercapacitors.

Performance characteristics of supercapacitor electrodes made of silicon carbide nanowires grown on carbon fabric

NASA Astrophysics Data System (ADS)

Gu, Lin; Wang, Yewu; Fang, Yanjun; Lu, Ren; Sha, Jian

2013-12-01

In this paper, we report the supercapacitor electrodes with excellent cycle stability, which are made of silicon carbide nanowires (SiC NWs) grown on flexible carbon fabric. A high areal capacitance of 23 mF cm-2 is achieved at a scan rate of 50 mV s-1 at room temperature and capacitances increase with the rise of the working temperature. Owing to the excellent thermal stability of SiC NWs and carbon fabric, no observable decrease of capacitance occurs at room temperature (20 °C) after 105 cycles, which satisfies the demands of the commercial applications. Further increasing the measurement temperature to 60 °C, 90% of the initial capacitance is still retained after 105 cycles. This study shows that silicon carbide nanowires on carbon fabric are a promising electrode material for high temperature and stable micro-supercapacitors.

Functionalized graphene hydrogel-based high-performance supercapacitors.

PubMed

Xu, Yuxi; Lin, Zhaoyang; Huang, Xiaoqing; Wang, Yang; Huang, Yu; Duan, Xiangfeng

2013-10-25

Functionalized graphene hydrogels are prepared by a one-step low-temperature reduction process and exhibit ultrahigh specific capacitances and excellent cycling stability in the aqueous electrolyte. Flexible solid-state supercapacitors based on functionalized graphene hydrogels are demonstrated with superior capacitive performances and extraordinary mechanical flexibility. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

N/S Co-doped Carbon Derived From Cotton as High Performance Anode Materials for Lithium Ion Batteries.

PubMed

Xiong, Jiawen; Pan, Qichang; Zheng, Fenghua; Xiong, Xunhui; Yang, Chenghao; Hu, Dongli; Huang, Chunlai

2018-01-01

Highly porous carbon with large surface areas is prepared using cotton as carbon sources which derived from discard cotton balls. Subsequently, the sulfur-nitrogen co-doped carbon was obtained by heat treatment the carbon in presence of thiourea and evaluated as Lithium-ion batteries anode. Benefiting from the S, N co-doping, the obtained S, N co-doped carbon exhibits excellent electrochemical performance. As a result, the as-prepared S, N co-doped carbon can deliver a high reversible capacity of 1,101.1 mA h g -1 after 150 cycles at 0.2 A g -1 , and a high capacity of 531.2 mA h g -1 can be observed even after 5,000 cycles at 10.0 A g -1 . Moreover, excellently rate capability also can be observed, a high capacity of 689 mA h g -1 can be obtained at 5.0 A g -1 . This superior lithium storage performance of S, N co-doped carbon make it as a promising low-cost and sustainable anode for high performance lithium ion batteries.

N/S co-doped carbon derived from Cotton as high performance anode materials for lithium ion batteries

NASA Astrophysics Data System (ADS)

Xiong, Jiawen; Pan, Qichang; Zheng, Fenghua; Xiong, Xunhui; Yang, Chenghao; Hu, Dongli; Huang, Chunlai

2018-04-01

Highly porous carbon with large surface areas is prepared using cotton as carbon sources which derived from discard cotton balls. Subsequently, the sulfur-nitrogen co-doped carbon was obtained by heat treatment the carbon in presence of thiourea and evaluated as Lithium-ion batteries anode. Benefiting from the S, N co-doping, the obtained S, N co-doped carbon exhibits excellent electrochemical performance. As a result, the as-prepared S, N co-doped carbon can deliver a high reversible capacity of 1101.1 mA h g-1 after 150 cycles at 0.2 A g-1, and a high capacity of 531.2 mA h g-1 can be observed even after 5000 cycles at 10.0 A g-1. Moreover, excellently rate capability also can be observed, a high capacity of 689 mA h g-1 can be obtained at 5.0 A g-1. This superior lithium storage performance of S, N co-doped carbon make it as a promising low-cost and sustainable anode for high performance lithium ion batteries.

N/S Co-doped Carbon Derived From Cotton as High Performance Anode Materials for Lithium Ion Batteries

PubMed Central

Xiong, Jiawen; Pan, Qichang; Zheng, Fenghua; Xiong, Xunhui; Yang, Chenghao; Hu, Dongli; Huang, Chunlai

2018-01-01

Highly porous carbon with large surface areas is prepared using cotton as carbon sources which derived from discard cotton balls. Subsequently, the sulfur-nitrogen co-doped carbon was obtained by heat treatment the carbon in presence of thiourea and evaluated as Lithium-ion batteries anode. Benefiting from the S, N co-doping, the obtained S, N co-doped carbon exhibits excellent electrochemical performance. As a result, the as-prepared S, N co-doped carbon can deliver a high reversible capacity of 1,101.1 mA h g−1 after 150 cycles at 0.2 A g−1, and a high capacity of 531.2 mA h g−1 can be observed even after 5,000 cycles at 10.0 A g−1. Moreover, excellently rate capability also can be observed, a high capacity of 689 mA h g−1 can be obtained at 5.0 A g−1. This superior lithium storage performance of S, N co-doped carbon make it as a promising low-cost and sustainable anode for high performance lithium ion batteries. PMID:29755966

Hierarchical porous NiCo2O4 nanowires for high-rate supercapacitors.

PubMed

Jiang, Hao; Ma, Jan; Li, Chunzhong

2012-05-11

We demonstrate a simple and scalable strategy for synthesizing hierarchical porous NiCo(2)O(4) nanowires which exhibit a high specific capacitance of 743 F g(-1) at 1 A g(-1) with excellent rate performance (78.6% capacity retention at 40 A g(-1)) and cycling stability (only 6.2% loss after 3000 cycles). This journal is © The Royal Society of Chemistry 2012

Capacitance enhancement of polyaniline coated curved-graphene supercapacitors in a redox-active electrolyte.

PubMed

Chen, Wei; Rakhi, R B; Alshareef, H N

2013-05-21

We show, for the first time, a redox-active electrolyte in combination with a polyaniline-coated curved graphene active material to achieve significant enhancement in the capacitance (36-92% increase) compared to supercapacitors that lack the redox-active contribution from the electrolyte. The supercapacitors based on the redox-active electrolyte also exhibit excellent rate capability and very long cycling performance (>50,000 cycles).

Electric papers of graphene-coated Co₃O₄ fibers for high-performance lithium-ion batteries.

PubMed

Yang, Xiaoling; Fan, Kaicai; Zhu, Yihua; Shen, Jianhua; Jiang, Xin; Zhao, Peng; Luan, Shaorong; Li, Chunzhong

2013-02-01

A facile strategy to synthesize the novel composite paper of graphene nanosheets (GNS) coated Co(3)O(4) fibers is reported as an advanced anode material for high-performance lithium-ion batteries (LIBs). The GNS were able to deposit onto Co(3)O(4) fibers and form the coating via electrostatic interactions. The unique hybrid paper is evaluated as an anode electrode for LIBs, and it exhibits a very large reversible capacity (∼840 mA h g(-1) after 40 cycles), excellent cyclic stability and good rate capacity. The substantially excellent electrochemical performance of the graphene/Co(3)O(4) composite paper is the result from its unique features. Notably, the flexible structure of graphenic scaffold and the strong interaction between graphene and Co(3)O(4) fibers are beneficial for providing excellent electronic conductivity, short transportation length for lithium ions, and elastomeric space to accommodate volume varies upon Li(+) insertion/extraction.

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.

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.

Noncovalently-functionalized reduced graphene oxide sheets by water-soluble methyl green for supercapacitor application

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

Ren, Xiaoying; Hu, Zhongai, E-mail: zhongai@nwnu.edu.cn; Hu, Haixiong

2015-10-15

Graphical abstract: Electroactive methyl green (MG) is selected to functionalize reduced graphene oxide (RGO) through non-covalent modification and the composite achieves high specific capacitance, good rate capability and excellent long life cycle. - Highlights: • MG–RGO composites were firstly prepared through non-covalent modification. • The mass ratio in composites is a key for achieving high specific capacitance. • MG–RGO 5:4 exhibits the highest specific capacitance of 341 F g{sup −1}. • MG–RGO 5:4 shows excellent rate capability and long life cycle. - Abstract: In the present work, water-soluble electroactive methyl green (MG) has been used to non-covalently functionalize reduced graphenemore » oxide (RGO) for enhancing supercapacitive performance. The microstructure, composition and morphology of MG–RGO composites are systematically characterized by UV–vis absorption, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical performances are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS). The fast redox reactions from MG could generate additional pseudocapacitance, which endows RGO higher capacitances. As a result, the MG–RGO composite (with the 5:4 mass ratio of MG:RGO) achieve a maximum value of 341 F g{sup −1} at 1 A g{sup −1} within the potential range from −0.25 to 0.75 V and provide a 180% enhancement in specific capacitance in comparison with pure RGO. Furthermore, excellent rate capability (72% capacitance retention from 1 A g{sup −1} to 20 A g{sup −1}) and long life cycle (12% capacitance decay after 5000 cycles) are achieved for the MG–RGO composite electrode.« less

High electrochemical performances of hierarchical hydrangea macrophylla like NiCo{sub 2}O{sub 4} and NiCo{sub 2}S{sub 4} as anode materials for Li-ion batteries

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

Jin, Rencheng, E-mail: jinrc427@126.com; Liu, Gang; Liu, Chunping

2016-08-15

Graphical abstract: Mesoporous hydrangea macrophylla like NiCo{sub 2}O{sub 4} and NiCo{sub 2}S{sub 4} have been fabricated, which present excellent electrochemical performances as anode materials for Li-ion batteries. - Highlights: • Hierarchical NiCo{sub 2}O{sub 4} is successfully fabricated. • Hierarchical NiCo{sub 2}S{sub 4} is prepared via sulfide anion exchange. • The hierarchical NiCo{sub 2}O{sub 4} and NiCo{sub 2}S{sub 4} exhibit good electrochemical properties. - Abstract: In this work, hierarchical hydrangea macrophylla like NiCo{sub 2}O{sub 4} has been synthesized by solvothermal method followed by calcination treatment in air. By using Na{sub 2}S as sulfur source, the NiCo{sub 2}O{sub 4} is converted intomore » NiCo{sub 2}S{sub 4}. Such hierarchical NiCo{sub 2}O{sub 4} exhibits a high specific capacity and excellent cycling stability (928 mAh g{sup −1} at a current density of 100 mA g{sup −1} after 100 cycles). Even at high current density of 2000 mA g{sup −1}, the electrode still delivers a specific capacity of 371 mAh g{sup −1} after 50 cycles. When the NiCo{sub 2}S{sub 4} is used as anode materials for lithium-ion batteries, a high discharge capacity of 1204 mAh g{sup −1} can be achieved. Meanwhile, the NiCo{sub 2}S{sub 4} electrode displays good cycling stability and rate capability. The excellent electrochemical performances can be attributed to the unique porous structure, which can effectively reduce the diffusion length for lithium ions and electrons, and alleviate volume expansion during the charge-discharge processes.« less

Lithium Batteries and Supercapacitors Capable of Operating at Low Temperatures for Planetary Exploration

NASA Technical Reports Server (NTRS)

Smart, M. C.; Ratnakumar, B. V.; West, W. C.; Brandon, E. J.

2012-01-01

Demonstrated improved performance with wide operating temperature electrolytes containing ester co - solvents (i.e., methyl propionate and ethyl butyrate) in a number of prototype cells: center dot Successfully scaled up low temperature technology to 12 Ah size prismatic Li - ion cells (Quallion, LCC), and demonstrated good performance down to - 60 o C. center dot Demonstrated wide operating temperature range performance ( - 60 o to +60 o C) in A123 Systems LiFePO 4 - based lithium - ion cells containing methyl butyrate - based low temperature electrolytes. These systems were also demonstrated to have excellent cycle life performance at ambient temperatures, as well as the ability to be cycled up to high temperatures.

Enhanced cycling stability of NiCo2S4@NiO core-shell nanowire arrays for all-solid-state asymmetric supercapacitors.

PubMed

Huang, Yuanyuan; Shi, Tielin; Jiang, Shulan; Cheng, Siyi; Tao, Xiangxu; Zhong, Yan; Liao, Guanglan; Tang, Zirong

2016-12-07

As a new class of pseudocapacitive material, metal sulfides possess high electrochemical performance. However, their cycling performance as conventional electrodes is rather poor for practical applications. In this article, we report an original composite electrode based on NiCo 2 S 4 @NiO core-shell nanowire arrays (NWAs) with enhanced cycling stability. This three-dimensional electrode also has a high specific capacitance of 12.2 F cm -2 at the current density of 1 mA cm -2 and excellent cycling stability (about 89% retention after 10,000 cycles). Moreover, an all-solid-state asymmetric supercapacitor (ASC) device has been assembled with NiCo 2 S 4 @NiO NWAs as the positive electrode and active carbon (AC) as the negative electrode, delivering a high energy density of 30.38 W h kg -1 at 0.288 KW kg -1 and good cycling stability (about 109% retention after 5000 cycles). The results show that NiCo 2 S 4 @NiO NWAs are promising for high-performance supercapacitors with stable cycling based on the unique core-shell structure and well-designed combinations.

Enhanced cycling stability of NiCo2S4@NiO core-shell nanowire arrays for all-solid-state asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Huang, Yuanyuan; Shi, Tielin; Jiang, Shulan; Cheng, Siyi; Tao, Xiangxu; Zhong, Yan; Liao, Guanglan; Tang, Zirong

2016-12-01

As a new class of pseudocapacitive material, metal sulfides possess high electrochemical performance. However, their cycling performance as conventional electrodes is rather poor for practical applications. In this article, we report an original composite electrode based on NiCo2S4@NiO core-shell nanowire arrays (NWAs) with enhanced cycling stability. This three-dimensional electrode also has a high specific capacitance of 12.2 F cm-2 at the current density of 1 mA cm-2 and excellent cycling stability (about 89% retention after 10,000 cycles). Moreover, an all-solid-state asymmetric supercapacitor (ASC) device has been assembled with NiCo2S4@NiO NWAs as the positive electrode and active carbon (AC) as the negative electrode, delivering a high energy density of 30.38 W h kg-1 at 0.288 KW kg-1 and good cycling stability (about 109% retention after 5000 cycles). The results show that NiCo2S4@NiO NWAs are promising for high-performance supercapacitors with stable cycling based on the unique core-shell structure and well-designed combinations.

Enhanced cycling stability of NiCo2S4@NiO core-shell nanowire arrays for all-solid-state asymmetric supercapacitors

PubMed Central

Huang, Yuanyuan; Shi, Tielin; Jiang, Shulan; Cheng, Siyi; Tao, Xiangxu; Zhong, Yan; Liao, Guanglan; Tang, Zirong

2016-01-01

As a new class of pseudocapacitive material, metal sulfides possess high electrochemical performance. However, their cycling performance as conventional electrodes is rather poor for practical applications. In this article, we report an original composite electrode based on NiCo2S4@NiO core-shell nanowire arrays (NWAs) with enhanced cycling stability. This three-dimensional electrode also has a high specific capacitance of 12.2 F cm−2 at the current density of 1 mA cm−2 and excellent cycling stability (about 89% retention after 10,000 cycles). Moreover, an all-solid-state asymmetric supercapacitor (ASC) device has been assembled with NiCo2S4@NiO NWAs as the positive electrode and active carbon (AC) as the negative electrode, delivering a high energy density of 30.38 W h kg−1 at 0.288 KW kg−1 and good cycling stability (about 109% retention after 5000 cycles). The results show that NiCo2S4@NiO NWAs are promising for high-performance supercapacitors with stable cycling based on the unique core-shell structure and well-designed combinations. PMID:27924927

Polyaniline nanowire array encapsulated in titania nanotubes as a superior electrode for supercapacitors.

PubMed

Xie, Keyu; Li, Jie; Lai, Yanqing; Zhang, Zhi'an; Liu, Yexiang; Zhang, Guoge; Huang, Haitao

2011-05-01

Conducting polymer with 1D nanostructure exhibits excellent electrochemical performances but a poor cyclability that limits its use in supercapacitors. In this work, a novel composite electrode made of polyaniline nanowire-titania nanotube array was synthesized via a simple and inexpensive electrochemical route by electropolymerizing aniline onto an anodized titania nanotube array. The specific capacitance was as high as 732 F g(-1) at 1 A g(-1), which remained at 543 F g(-1) when the current density was increased by 20 times. 74% of the maximum energy density (36.6 Wh kg(-1)) was maintained even at a high power density of 6000 W kg(-1). An excellent long cycle life of the electrode was observed with a retention of ∼86% of the initial specific capacitance after 2000 cycles. The good electrochemical performance was attributed to the unique microstructure of the electrode with disordered PANI nanowire arrays encapsulated inside the TiO(2) nanotubes, providing high surface area, fast diffusion path for ions and long-term cycle stability. Such a nanocomposite electrode is attractive for supercapacitor applications. © The Royal Society of Chemistry 2011

Encapsulation of Fe3O4 Nanoparticles into N, S co-Doped Graphene Sheets with Greatly Enhanced Electrochemical Performance

PubMed Central

Yang, Zunxian; Qian, Kun; Lv, Jun; Yan, Wenhuan; Liu, Jiahui; Ai, Jingwei; Zhang, Yuxiang; Guo, Tailiang; Zhou, Xiongtu; Xu, Sheng; Guo, Zaiping

2016-01-01

Particular N, S co-doped graphene/Fe3O4 hybrids have been successfully synthesized by the combination of a simple hydrothermal process and a subsequent carbonization heat treatment. The nanostructures exhibit a unique composite architecture, with uniformly dispersed Fe3O4 nanoparticles and N, S co-doped graphene encapsulant. The particular porous characteristics with many meso/micro holes/pores, the highly conductive N, S co-doped graphene, as well as the encapsulating N, S co-doped graphene with the high-level nitrogen and sulfur doping, lead to excellent electrochemical performance of the electrode. The N-S-G/Fe3O4 composite electrode exhibits a high initial reversible capacity of 1362.2 mAhg−1, a high reversible specific capacity of 1055.20 mAhg−1 after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 556.69 mAhg−1 when cycled at the current density of 1000 mAg−1, indicating that the N-S-G/Fe3O4 composite is a promising anode candidate for Li-ion batteries. PMID:27296103

MoS2/Ni3S4 composite nanosheets on interconnected carbon shells as an excellent supercapacitor electrode architecture for long term cycling at high current densities

NASA Astrophysics Data System (ADS)

Qin, Shengchun; Yao, Tinghui; Guo, Xin; Chen, Qiang; Liu, Dequan; Liu, Qiming; Li, Yali; Li, Junshuai; He, Deyan

2018-05-01

In this paper, we report an electrode architecture of molybdenum disulfide (MoS2)/nickel sulfide (Ni3S4) composite nanosheets anchored on interconnected carbon (C) shells (C@MoS2/Ni3S4). Electrochemical measurements indicate that the C@MoS2/Ni3S4 structure possesses excellent supercapacitive properties especially for long term cycling at high current densities. A specific capacitance as high as ∼640.7 F g-1 can still be delivered even after 10,000 cycles at a high current density of 20 A g-1. From comparison of microstructures and electrochemical properties of the related materials/structures, the improved performance of C@MoS2/Ni3S4 can be attributed to the relatively dispersedly distributed nanosheet-shaped MoS2/Ni3S4 that provides efficient contact with electrolyte and effectively buffers the volume change during charge/discharge processes, enhanced cycling stability by MoS2, and reduced equivalent series resistance by the interconnected C shells.

Hierarchical flower-like C/NiO composite hollow microspheres and its excellent supercapacitor performance

NASA Astrophysics Data System (ADS)

Liu, Tao; Jiang, Chuanjia; Cheng, Bei; You, Wei; Yu, Jiaguo

2017-08-01

Nickel (II) oxide (NiO) nanosheet grown on N-doped carbon hollow spheres (NiO/NCHS) with hierarchical pore structure are obtained via facile chemical bath deposition followed by calcination at 350 °C under nitrogen atmosphere. Phase structure measurements indicate that the material is composed of NiO and N-doped carbon. The NiO/NCHS composite exhibits a unique flower-like morphology, where ultrathin NiO nanosheets are vertically grown on the surface of NCHS. This hierarchical nanostructure is beneficial for facilitating electron and electrolyte ion transport and accelerating the reversible redox reaction. The specific capacitance of the NiO/NCHS composite (585 F g-1 at 1 A g-1) is higher than that of pure NiO particle (453 F g-1 at 1 A g-1). Meanwhile, the NiO/NCHS composite exhibits excellent rate performance and superior cycling stability over 6000 cycles. The enhanced supercapacitive performance of the NiO/NCHS nanocomposite indicates that it can be an appealing candidate electrode material for supercapacitors.

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.

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.

Robust electrodes based on coaxial TiC/C-MnO2 core/shell nanofiber arrays with excellent cycling stability for high-performance supercapacitors.

PubMed

Zhang, Xuming; Peng, Xiang; Li, Wan; Li, Limin; Gao, Biao; Wu, Guosong; Huo, Kaifu; Chu, Paul K

2015-04-17

A coaxial electrode structure composed of manganese oxide-decorated TiC/C core/shell nanofiber arrays is produced hydrothermally in a KMnO4 solution. The pristine TiC/C core/shell structure prepared on the Ti alloy substrate provides the self-sacrificing carbon shell and highly conductive TiC core, thus greatly simplifying the fabrication process without requiring an additional reduction source and conductive additive. The as-prepared electrode exhibits a high specific capacitance of 645 F g(-1) at a discharging current density of 1 A g(-1) attributable to the highly conductive TiC/C and amorphous MnO2 shell with fast ion diffusion. In the charging/discharging cycling test, the as-prepared electrode shows high stability and 99% capacity retention after 5000 cycles. Although the thermal treatment conducted on the as-prepared electrode decreases the initial capacitance, the electrode undergoes capacitance recovery through structural transformation from the crystalline cluster to layered birnessite type MnO2 nanosheets as a result of dissolution and further electrodeposition in the cycling. 96.5% of the initial capacitance is retained after 1000 cycles at high charging/discharging current density of 25 A g(-1). This study demonstrates a novel scaffold to construct MnO2 based SCs with high specific capacitance as well as excellent mechanical and cycling stability boding well for future design of high-performance MnO2-based SCs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of staff performance and interpretation of the screening program for prevention of thalassemia.

PubMed

Prommetta, Simaporn; Sanchaisuriya, Kanokwan; Fucharoen, Goonnapa; Yamsri, Supawadee; Chaiboonroeng, Attawut; Fucharoen, Supan

2017-06-15

Thalassemia screening program has been implemented for years in Southeast Asia, but no external quality assessment program has been established. We have developed and initiated the proficiency testing (PT) program for the first time in Thailand with the aim to assess the screening performance of laboratory staff and their competency in interpretation of the screening results. Three PT cycles per year were organized. From the first to the third cycle of the PT scheme, a total number of participant laboratories increased from 59 to 67. In each cycle, 2 PT items (assigned as blood samples of the couple) were provided. Performance evaluation was based on the accuracy of screening results, i.e . mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and the dichlorophenolindophenol (DCIP) test for haemoglobin E, including the competency in interpretation of screening results and assessment of foetal risk. Performance was assessed by comparing the participants' result against the assigned value. Of all 3 cycles, most laboratories reported acceptable MCV and MCH values. From the first to the third cycle, incorrect DCIP test and misinterpretation rates were decreased while incorrect risk assessment varied by cycle to cycle. Combining the accuracy of thalassemia screening and the competency in interpretation and risk assessment, approximately half of participants showed excellent performance. Improved performance observed in many laboratories reflects the achievement and benefit of the PT program which should be regularly provided.

Nitrogen-doped carbon coated MnO nanopeapods as superior anode materials for lithium ion batteries

NASA Astrophysics Data System (ADS)

Ding, Yu; Chen, Lihui; Pan, Pei; Du, Jun; Fu, Zhengbing; Qin, Caiqin; Wang, Feng

2017-11-01

High performance nitrogen-doped carbon (NC) materials decorated with MnO hybrid (MnO@NC) composites with a nanopeapod appearance were synthesized by with a simple hydrothermal method and insuit-polymeric route. As an anode material for lithium ion batteries (LIBs), the nanopeapod structure of MnO@NC composites with internal void spaces exhibits good rate capability, high conductivity and excellent cycling stability. After 200 cycles, the nanopeapod composites yield a specific capacity of 775.4 mAh g-1 at 100 mA g-1 and a high-rate capacity of 559.7 mAh g-1 at 1000 mA g-1. The proposed synthesis of nanopeapod structure composites with an internal room is an efficient design with excellent electrode materials for rechargeable LIBs.

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.

Nb{sub 2}O{sub 5} hollow nanospheres as anode material for enhanced performance in lithium ion batteries

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

Sasidharan, Manickam; Gunawardhana, Nanda; Yoshio, Masaki, E-mail: yoshio@cc.saga-u.ac.jp

2012-09-15

Graphical abstract: Nb{sub 2}O{sub 5} hollow nanosphere constructed electrode delivers high capacity of 172 mAh g{sup −1} after 250 cycles and maintains structural integrity and excellent cycling stability. Highlights: ► Nb{sub 2}O{sub 5} hollow nanospheres synthesis was synthesized by soft-template. ► Nb{sub 2}O{sub 5} hollow nanospheres were investigated as anode material in Li-ion battery. ► Nanostructured electrode delivers high capacity of 172 mAh g{sup −1} after 250 cycles. ► The electrode maintains the structural integrity and excellent cycling stability. ► Nanosized shell domain facilitates fast lithium intercalation/deintercalation. -- Abstract: Nb{sub 2}O{sub 5} hollow nanospheres of average diameter ca. ∼29 nmmore » and hollow cavity size ca. 17 nm were synthesized using polymeric micelles with core–shell–corona architecture under mild conditions. The hollow particles were thoroughly characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermal (TG/DTA) and nitrogen adsorption analyses. Thus obtained Nb{sub 2}O{sub 5} hollow nanospheres were investigated as anode materials for lithium ion rechargeable batteries for the first time. The nanostructured electrode delivers high capacity of 172 mAh g{sup −1} after 250 cycles of charge/discharge at a rate of 0.5 C. More importantly, the hollow particles based electrodes maintains the structural integrity and excellent cycling stability even after exposing to high current density 6.25 A g{sup −1}. The enhanced electrochemical behavior is ascribed to hollow cavity coupled with nanosized Nb{sub 2}O{sub 5} shell domain that facilitates fast lithium intercalation/deintercalation kinetics.« less

Porous MoO2 nanowires as stable and high-rate negative electrodes for electrochemical capacitors.

PubMed

Zheng, Dezhou; Feng, Haobin; Zhang, Xiyue; He, Xinjun; Yu, Minghao; Lu, Xihong; Tong, Yexiang

2017-04-04

Free-standing porous MoO 2 nanowires with extraordinary capacitive performance are developed as high-performance electrodes for electrochemical capacitors. The as-obtained MoO 2 electrode exhibits a remarkable capacitance of 424.4 mF cm -2 with excellent electrochemical durability (no capacitance decay after 10 000 cycles at various scan rates).

Facile construction of 3D graphene/MoS2 composites as advanced electrode materials for supercapacitors

NASA Astrophysics Data System (ADS)

Sun, Tianhua; Li, Zhangpeng; Liu, Xiaohong; Ma, Limin; Wang, Jinqing; Yang, Shengrong

2016-11-01

Flower-like molybdenum disulfide (MoS2) microstructures are synthesized based on three-dimensional graphene (3DG) skeleton via a simple and facile one-step hydrothermal method, aiming at constructing series of novel composite electrode materials of 3DG/MoS2 with high electrochemical performances for supercapacitors. The electrochemical properties of the samples are evaluated by cyclic voltammetry and galvanostatic charge/discharge tests. Specifically, the optimal 3DG/MoS2 composite exhibits remarkable performances with a high specific capacitance of 410 F g-1 at a current density of 1 A g-1 and an excellent cycling stability with ca. 80.3% capacitance retention after 10,000 continuous charge-discharge cycles at a high current density of 2 A g-1, making it adaptive for high-performance supercapacitors. The enhanced electrochemical performances can be ascribed to the combination of 3DG and flower-like MoS2, which provides excellent charge transfer network and electrolyte diffusion channels while effectively prevents the collapse, aggregation and morphology change of active materials during charge-discharge process. The results demonstrate that 3DG/MoS2 composite is one of the attractive electrode materials for supercapacitors.

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

Xiao, Anguo, E-mail: hixiaoanguo@126.com; Zhou, Shibiao; Zuo, Chenggang

Graphical abstract: CuO nanotube array electrodes prepared by electrodeposition method exhibit an excellent lithium ion storage ability as anode of Li-ion battery. - Highlights: • CuO nanotube arrays are synthesized by an electrodeposition method. • CuO nanotube shows a high-rate performance. • CuO nanotube shows an excellent cycling performance. - Abstract: We report a facile strategy to prepared CuO nanotube arrays directly grown on Cu plate through the electrodeposition method. The as-prepared CuO nanotubes show a quasi-cylinder nanostructure with internal diameters of ca. ∼100 nm, external diameters of ca. ∼120 nm, and average length of ∼3 μm. As an anodemore » for lithium ion batteries, the electrochemical properties of the CuO nanotube arrays are investigated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests. Due to the unique nanotube nanostructure, the as-prepared CuO electrodes exhibit good rate performance (550 mAh g{sup −1} at 0.1 C and 464 mAh g{sup −1} at 1 C) and cycling performance (581 mAh g{sup −1} at 0.1 C and 538 mAh g{sup −1} at 0.5 C)« less

Cycle development and design for CO{sub 2} capture from flue gas by vacuum swing adsorption

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

Jun Zhang; Paul A. Webley

CO{sub 2} capture and storage is an important component in the development of clean power generation processes. One CO{sub 2} capture technology is gas-phase adsorption, specifically pressure (or vacuum) swing adsorption. The complexity of these processes makes evaluation and assessment of new adsorbents difficult and time-consuming. In this study, we have developed a simple model specifically targeted at CO{sub 2} capture by pressure swing adsorption and validated our model by comparison with data from a fully instrumented pilot-scale pressure swing adsorption process. The model captures non-isothermal effects as well as nonlinear adsorption and nitrogen coadsorption. Using the model and ourmore » apparatus, we have designed and studied a large number of cycles for CO{sub 2} capture. We demonstrate that by careful management of adsorption fronts and assembly of cycles based on understanding of the roles of individual steps, we are able to quickly assess the effect of adsorbents and process parameters on capture performance and identify optimal operating regimes and cycles. We recommend this approach in contrast to exhaustive parametric studies which tend to depend on specifics of the chosen cycle and adsorbent. We show that appropriate combinations of process steps can yield excellent process performance and demonstrate how the pressure drop, and heat loss, etc. affect process performance through their effect on adsorption fronts and profiles. Finally, cyclic temperature profiles along the adsorption column can be readily used to infer concentration profiles - this has proved to be a very useful tool in cyclic function definition. Our research reveals excellent promise for the application of pressure/vacuum swing adsorption technology in the arena of CO{sub 2} capture from flue gases. 20 refs., 6 figs., 2 tabs.« less

Cycle development and design for CO2 capture from flue gas by vacuum swing adsorption.

PubMed

Zhang, Jun; Webley, Paul A

2008-01-15

CO2 capture and storage is an important component in the development of clean power generation processes. One CO2 capture technology is gas-phase adsorption, specifically pressure (or vacuum) swing adsorption. The complexity of these processes makes evaluation and assessment of new adsorbents difficult and time-consuming. In this study, we have developed a simple model specifically targeted at CO2 capture by pressure swing adsorption and validated our model by comparison with data from a fully instrumented pilot-scale pressure swing adsorption process. The model captures nonisothermal effects as well as nonlinear adsorption and nitrogen coadsorption. Using the model and our apparatus, we have designed and studied a large number of cycles for CO2 capture. We demonstrate that by careful management of adsorption fronts and assembly of cycles based on understanding of the roles of individual steps, we are able to quickly assess the effect of adsorbents and process parameters on capture performance and identify optimal operating regimes and cycles. We recommend this approach in contrast to exhaustive parametric studies which tend to depend on specifics of the chosen cycle and adsorbent. We show that appropriate combinations of process steps can yield excellent process performance and demonstrate how the pressure drop, and heat loss, etc. affect process performance through their effect on adsorption fronts and profiles. Finally, cyclic temperature profiles along the adsorption column can be readily used to infer concentration profiles-this has proved to be a very useful tool in cyclic function definition. Our research reveals excellent promise for the application of pressure/vacuum swing adsorption technology in the arena of CO2 capture from flue gases.

Electrochemical potassium-ion intercalation in NaxCoO2: a novel cathode material for potassium-ion batteries.

PubMed

Sada, Krishnakanth; Senthilkumar, Baskar; Barpanda, Prabeer

2017-07-27

Reversible electrochemical potassium-ion intercalation in P2-type Na x CoO 2 was examined for the first time. Hexagonal Na 0.84 CoO 2 platelets prepared by a solution combustion synthesis technique were found to work as an efficient host for K + intercalation. They deliver a high reversible capacity of 82 mA h g -1 , good rate capability and excellent cycling performance up to 50 cycles.

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.

Cycling and floating performance of symmetric supercapacitor derived from coconut shell biomass

NASA Astrophysics Data System (ADS)

Barzegar, Farshad; Khaleed, Abubakar A.; Ugbo, Faith U.; Oyeniran, Kabir O.; Momodu, Damilola Y.; Bello, Abdulhakeem; Dangbegnon, Julien K.; Manyala, Ncholu

2016-11-01

This work present two-step synthesizes route to low-cost mesoporous carbon from coconut shell. The electrochemical characterization of the coconut shell based activated carbon (CSAC) material as electrode for supercapacitor showed a specific capacitance of 186 F g-1, energy density of ˜11 Wh kg-1 and power density of 325 W kg-1 at a 0.5 A g-1 with an excellent stability after floating for 100 h and cycling for 10000 cycles in polymer gel electrolyte. The CSAC showed very good potential as a stable material for supercapacitors desirable for high power applications.

Synthesis of ultrathin nitrogen-doped graphitic carbon nanocages as advanced electrode materials for supercapacitor.

PubMed

Tan, Yueming; Xu, Chaofa; Chen, Guangxu; Liu, Zhaohui; Ma, Ming; Xie, Qingji; Zheng, Nanfeng; Yao, Shouzhuo

2013-03-01

Synthesis of nitrogen-doped carbons with large surface area, high conductivity, and suitable pore size distribution is highly desirable for high-performance supercapacitor applications. Here, we report a novel protocol for template synthesis of ultrathin nitrogen-doped graphitic carbon nanocages (CNCs) derived from polyaniline (PANI) and their excellent capacitive properties. The synthesis of CNCs involves one-pot hydrothermal synthesis of Mn3O4@PANI core-shell nanoparticles, carbonization to produce carbon coated MnO nanoparticles, and then removal of the MnO cores by acidic treatment. The CNCs prepared at an optimum carbonization temperature of 800 °C (CNCs-800) have regular frameworks, moderate graphitization, high specific surface area, good mesoporosity, and appropriate N doping. The CNCs-800 show high specific capacitance (248 F g(-1) at 1.0 A g(-1)), excellent rate capability (88% and 76% capacitance retention at 10 and 100 A g(-1), respectively), and outstanding cycling stability (~95% capacitance retention after 5000 cycles) in 6 M KOH aqueous solution. The CNCs-800 can also exhibit great pseudocapacitance in 0.5 M H2SO4 aqueous solution besides the large electrochemical double-layer capacitance. The excellent capacitance performance coupled with the facile synthesis of ultrathin nitrogen-doped graphitic CNCs indicates their great application potential in supercapacitors.

Flexible, transparent and high-power triboelectric generator with asymmetric graphene/ITO electrodes.

PubMed

Song, Xinbo; Chen, Yuanfu; Li, Pingjian; Liu, Jingbo; Qi, Fei; Zheng, Binjie; Zhou, Jinhao; Hao, Xin; Zhang, Wanli

2016-07-29

The reported flexible and transparent triboelectric generator (FTTG) can only output ultralow power density (∼2 μW cm(-2)), which has seriously hindered its further development and application. The low power density of FTTG is mainly limited by the transparent material and the electrode structure. Herein, for the first time, a FTTG with a superior power density of 60.7 μW cm(-2) has been fabricated by designing asymmetric electrodes where graphene and indium tin oxide (ITO) act as top and bottom electrodes respectively. Moreover, the performance of FTTG with graphene/ITO (G/I) asymmetric electrodes (GI-FTTG) almost remains unchanged even after 700 cycles, indicating excellent mechanical stability. The excellent performance of GI-FTTG can be attributed to the suitable materials and unique asymmetric electrode structure: the extraordinary flexibility of the graphene top electrode ensures the GI-FTTG excellent mechanical robustness and stability even after longer cycles, and the bottom electrode with very low sheet resistance guarantees lower internal resistance and higher production rate of induction charges to obtain higher output power density. It shows that light-emitting diodes (LED) can be easily powered by GI-FTTG, which demonstrates that the GI-FTTG is very promising for harvesting electrical energy from human activities by using flexible and transparent devices.

One-step synthesis of free-standing α-Ni(OH)2 nanosheets on reduced graphene oxide for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Dong, Bitao; Zhou, Han; Liang, Jin; Zhang, Lusi; Gao, Guoxin; Ding, Shujiang

2014-10-01

In this work, a hierarchical hybrid structure of reduced graphene oxide (rGO) supported ultrathin α-Ni(OH)2 nanosheets (denoted as α-Ni(OH)2@rGO NSs) has been developed successfully via an environmentally friendly one-step solution method. The resulting product of α-Ni(OH)2@rGO NSs was further characterized by scanning electron microscope, transmission electron microscope, x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller. The ultrathin α-Ni(OH)2 nanosheets of around 6 nm in thickness are uprightly coated on the double sides of rGO substrate. When evaluated as electrodes for supercapacitors, the hybrid α-Ni(OH)2@rGO NSs demonstrate excellent supercapacitor performance and cycling stability, compared with the self-aggregated α-Ni(OH)2 powder. Even after 2000 cycles, the hybrid electrodes still can deliver a specific capacitance of 1300 F g-1 at the current density of 5 A g-1, corresponding to no capacity loss of the initial cycle. Such excellent electrochemical performance should be attributed to the ultrathin, free-standing, and hierarchical nanosheets of α-Ni(OH)2, which not only promote efficient charge transport and facilitate the electrolyte diffusion, but also prevent aggregation of electro-active materials effectively during the charge-discharge process.

One-step synthesis of free-standing α-Ni(OH)₂ nanosheets on reduced graphene oxide for high-performance supercapacitors.

PubMed

Dong, Bitao; Zhou, Han; Liang, Jin; Zhang, Lusi; Gao, Guoxin; Ding, Shujiang

2014-10-31

In this work, a hierarchical hybrid structure of reduced graphene oxide (rGO) supported ultrathin α-Ni(OH)2 nanosheets (denoted as α-Ni(OH)2@rGO NSs) has been developed successfully via an environmentally friendly one-step solution method. The resulting product of α-Ni(OH)2@rGO NSs was further characterized by scanning electron microscope, transmission electron microscope, x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller. The ultrathin α-Ni(OH)2 nanosheets of around 6 nm in thickness are uprightly coated on the double sides of rGO substrate. When evaluated as electrodes for supercapacitors, the hybrid α-Ni(OH)2@rGO NSs demonstrate excellent supercapacitor performance and cycling stability, compared with the self-aggregated α-Ni(OH)2 powder. Even after 2000 cycles, the hybrid electrodes still can deliver a specific capacitance of 1300 F g(-1) at the current density of 5 A g(-1), corresponding to no capacity loss of the initial cycle. Such excellent electrochemical performance should be attributed to the ultrathin, free-standing, and hierarchical nanosheets of α-Ni(OH)2, which not only promote efficient charge transport and facilitate the electrolyte diffusion, but also prevent aggregation of electro-active materials effectively during the charge-discharge process.

Three-Dimensional Hierarchically Mesoporous ZnCo2 O4 Nanowires Grown on Graphene/Sponge Foam for High-Performance, Flexible, All-Solid-State Supercapacitors.

PubMed

Moon, In Kyu; Yoon, Seonno; Oh, Jungwoo

2017-01-12

To achieve high energy storage on three-dimensional (3D) structures at low cost, materials with high power and long cycle life characteristics have to be developed. We synthesized ZnCo 2 O 4 /reduced graphene oxide (rGO) binary composites in commercial sponges. ZnCo 2 O 4 nanosheets were grown on the surface of GO/sponge through a hydrothermal reaction. The resulting flexible, free-standing ZnCo 2 O 4 /rGO/sponge electrodes were used as the electrodes in a symmetric supercapacitor. ZnCo 2 O 4 /rGO/sponge electrodes have a large specific capacitance of 1116.6 F g -1 at a scan rate of 2 mV s -1 in aqueous electrolyte. The all-solid-state flexible supercapacitor is assembled based on ZnCo 2 O 4 /rGO/sponge electrodes, which show excellent electrochemical performances with a specific capacitance of 143 F g -1 at a current density of 1 A g -1 . The as-fabricated supercapacitor also exhibits excellent cycling stability (93.4 % capacitance retention after 5000 cycles) and exceptional mechanical flexibility. These results demonstrate the potential of ZnCo 2 O 4 /rGO/sponge as an electrode in flexible, high-performance supercapacitors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Free-standing anode of N-doped carbon nanofibers containing SnO{sub x} for high-performance lithium batteries

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

Zou, Mingzhong; Li, Jiaxin, E-mail: ljx3012982@yahoo.com; Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002

2014-12-15

Highlights: • Self-standing SnO{sub x} N-CNF electrodes were synthesized by electrospinning. • The SnO{sub x} N-CNFs anode exhibits high capacity, good cyclic stability, and excellent rate performance for lithium ion batteries. • The enhanced performance is ascribed to the synergetic effects between N-CNFs and SnO{sub x} nanoparticles. - Abstract: Free-standing paper of N-doped carbon nanofibers (NCNFs) containing SnO{sub x} was prepared by electrospinning. The structure and morphology of the sample were analyzed by XRD, XPS, SEM, and TEM. The results show that nitrogen atoms were successfully doped into CNFs. The SnO{sub x} were homogenously embedded in the N-doped CNFs viamore » annealing treatment. Subsequently, the SnO{sub x} NCNF paper was cut into disks and used as anodes for lithium ion batteries (LIBs). The anodes of SnO{sub x} NCNFs exhibit excellent cycling stability and show high capacity of 520 mA h g{sup −1} tested at a 200 mA g{sup −1} after 100 cycles. More importantly, at a high current density of 500 mA g{sup −1}, a large reversible capacity of 430 mA h g{sup −1} after 100 cycles can still be obtained. The good electrochemical performance should be attributed to the good electronic conductivity from the NCNFs and the synergistic effects from NCNFs and SnO{sub x} materials.« less

Thermal evaporation-induced anhydrous synthesis of Fe3O4-graphene composite with enhanced rate performance and cyclic stability for lithium ion batteries.

PubMed

Dong, Yucheng; Ma, Ruguang; Hu, Mingjun; Cheng, Hua; Yang, Qingdan; Li, Yang Yang; Zapien, Juan Antonio

2013-05-21

We present a high-yield and low cost thermal evaporation-induced anhydrous strategy to prepare hybrid materials of Fe3O4 nanoparticles and graphene as an advanced anode for high-performance lithium ion batteries. The ~10-20 nm Fe3O4 nanoparticles are densely anchored on conducting graphene sheets and act as spacers to keep the adjacent sheets separated. The Fe3O4-graphene composite displays a superior battery performance with high retained capacity of 868 mA h g(-1) up to 100 cycles at a current density of 200 mA g(-1), and 539 mA h g(-1) up to 200 cycles when cycling at 1000 mA g(-1), high Coulombic efficiency (above 99% after 200 cycles), good rate capability, and excellent cyclic stability. The simple approach offers a promising route to prepare anode materials for practical fabrication of lithium ion batteries.

High energy density of Li3-xNaxV2(PO4)3/C cathode material with high rate cycling performance for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Zuo, Zong-Lin; Deng, Jian-Qiu; Pan, Jin; Luo, Wen-Bin; Yao, Qing-Rong; Wang, Zhong-Min; Zhou, Huai-Ying; Liu, Hua-Kun

2017-07-01

A serials of micro-sized Li3-xNaxV2(PO4)3/C composite has been synthesized by sol-gel method, comprised of numerous primary nanocrystals. This structure can efficiently facilitate lithium-ion transport in secondary aggregated individual particles due to the short diffusion distance among primary nanocrystals, along with a high tap density. With the increasing of Na doping content, the structure evolution occurs in Li3-xNaxV2(PO4)3 from a single-phase structure to a two-phase structure. The appearance of rhombohedral phase can provide a larger free volume of the interstitial space, fastening ionic movement to offer an excellent high rate capability. Furthermore, Na doping can stabilize the rhombohedral structure of the V2(PO4)3 framework, leading to the remarkable cycling stability. Among all the composites, Li2.6Na0.4V2(PO4)3/C presents the best electrochemical performance with a high energy density of 478.8 Wh kg-1, delivering high initial discharge capacities of 121.6, 113.8 and 109.7 mAh g-1 at the rate of 5 C, 10 C and 20 C in a voltage range of 3.0 - 4.3 V, respectively. It also exhibit an excellent high rate cycling performance, with capacity retention of 85.9 %, 81.7 % and 76.5 % after 1000 cycles at the rate of 5 C, 10 C and 20 C in a voltage range of 3.0 - 4.3 V.

Pseudocapacitance and excellent cyclability of 2,5-dimethoxy-1,4-benzoquinone on graphene

DOE PAGES

Boota, Muhammad; Chen, Chi; Bécuwe, Matthieu; ...

2016-04-27

Electrochemically active organic materials are emerging as low cost, naturally abundant and sustainable alternatives to their metal-based counterparts. However, their usage in energy storage systems is mainly hindered by their poor conductivity, which results in capacitance fade upon cycling. In this paper, we present a redox-active xerogel composed of 2,5-dimethoxy-1,4-benzoquinone (DMQ) decorated on reduced graphene oxide (rGO) sheets via a hydrothermal method as a high capacitance and long cycle life pseudocapacitive electrode. DMQ not only provided stable redox-active centers but also served as a spacer to avoid rGO sheets aggregation and led to a three-dimensional (3D) hierarchical electrode architecture. Whenmore » a binder-free 50 μm thick rolled film was tested as a pseudocapacitive electrode, it exhibited an excellent capacitance of 650 F g -1 at 5 mV s -1 (780 F cm -3) in 1 M sulfuric acid, outperforming a large number of reported organic and inorganic electrodes. Most importantly, optimized electrodes showed an excellent capacitance retention of 99% after 25 000 cycles at 50 mV s -1. Density functional theory (DFT) calculations are further used to understand the charge storage mechanism, the preferred orientation of the adsorbed molecules, charge density distribution and density of states. In conclusion, our combined experimental and theoretical findings demonstrate that the careful selection of the conductive substrate, electrode architecture and organic molecules plays a crucial role in achieving high capacitance and long cycling performance.« less

3D-hybrid material design with electron/lithium-ion dual-conductivity for high-performance Li-sulfur batteries

NASA Astrophysics Data System (ADS)

Zhao, Yan; Tan, Rui; Yang, Jie; Wang, Kai; Gao, Rongtan; Liu, Dong; Liu, Yidong; Yang, Jinlong; Pan, Feng

2017-02-01

We report a novel 3D-hybrid cathode material with three-dimensional (3D) N-GO/CNT framework to load sulfur (77.6 wt %), and sulfonated polyaniline (SPANI) of coating layer. Used as a cathode material, it possesses a high capacity (1196 mAh g-1@0.3 A g-1@1.6 mg cm-2), excellent charging-discharging rate (680 mAh g-1@7.5 A g-1) and long-life performance (maintaining 71.1% capacity over 450 cycles), which is mainly attributed to the benefits of excellent electronic/Li-ionic dual-conductivity and confinement effect of the 3D-hybrid N-GO/CNT framework coated by self-doping conducting polymer SPANI. Thus, a 3D sulfur cathode modified with electronic/Li-ionic dual-conduction network can significantly enhance the electrochemical performance and stability, and this novel type of material is very promising for commercial applications that require high energy and power density, long life, and excellent abuse tolerance.

Highly conductive porous Na-embedded carbon nanowalls for high-performance capacitive deionization

NASA Astrophysics Data System (ADS)

Chang, Liang; Hu, Yun Hang

2018-05-01

Highly conductive porous Na-embedded carbon nanowalls (Na@C), which were recently invented, have exhibited excellent performance for dye-sensitized solar cells and electric double-layer capacitors. In this work, Na@C was demonstrated as an excellent electrode material for capacitive deionization (CDI). In a three-electrode configuration system, the specific capacity of the Na@C electrodes can achieve 306.4 F/g at current density of 0.2 A/g in 1 M NaCl, which is higher than that (235.2 F/g) of activated carbon (AC) electrodes. Furthermore, a high electrosorption capacity of 8.75 mg g-1 in 100 mg/L NaCl was obtained with the Na@C electrodes in a batch-mode capacitive deionization cell. It exceeds the electrosorption capacity (4.08 mg g-1) of AC electrodes. The Na@C electrode also showed a promising cycle stability. The excellent performance of Na@C electrode for capacitive deionization (CDI) can be attributed to its high electrical conductivity and large accessible surface area.

Hierarchical NiCo2 O4 nanosheets grown on Ni nanofoam as high-performance electrodes for supercapacitors.

PubMed

Gao, Guoxin; Wu, Hao Bin; Ding, Shujiang; Liu, Li-Min; Lou, Xiong Wen David

2015-02-18

A high-performance electrode for supercapacitors is designed and synthesized by growing electroactive NiCo2 O4 nanosheets on conductive Ni nanofoam. Because of the structural advantages, the as-prepared Ni@NiCo2 O4 hybrid nanostructure exhibits significantly improved electrochemical performance with high capacitance, excellent rate capability, and good cycling stability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Understanding Leadership Paradigms for Improvement in Higher Education

ERIC Educational Resources Information Center

Flumerfelt, Shannon; Banachowski, Michael

2011-01-01

Purpose: This research article is based on the Baldrige National Quality Program Education Criteria for Performance Excellence's conceptualization of improvement as a dual cycle/three element initiative of examining and bettering inputs, processes, and outputs as driven by measurement, analysis and knowledge management work. This study isolates a…

Bimetallic CoNiSx nanocrystallites embedded in nitrogen-doped carbon anchored on reduced graphene oxide for high-performance supercapacitors.

PubMed

Chen, Qidi; Miao, Jinkang; Quan, Liang; Cai, Daoping; Zhan, Hongbing

2018-02-22

Exploring high-performance and low-priced electrode materials for supercapacitors is important but remains challenging. In this work, a unique sandwich-like nanocomposite of reduced graphene oxide (rGO)-supported N-doped carbon embedded with ultrasmall CoNiS x nanocrystallites (rGO/CoNiS x /N-C nanocomposite) has been successfully designed and synthesized by a simple one-step carbonization/sulfurization treatment of the rGO/Co-Ni precursor. The intriguing structural/compositional/morphological advantages endow the as-synthesized rGO/CoNiS x /N-C nanocomposite with excellent electrochemical performance as an advanced electrode material for supercapacitors. Compared with the other two rGO/CoNiO x and rGO/CoNiS x nanocomposites, the rGO/CoNiS x /N-C nanocomposite exhibits much enhanced performance, including a high specific capacitance (1028.2 F g -1 at 1 A g -1 ), excellent rate capability (89.3% capacitance retention at 10 A g -1 ) and good cycling stability (93.6% capacitance retention over 2000 cycles). In addition, an asymmetric supercapacitor (ASC) device based on the rGO/CoNiS x /N-C nanocomposite as the cathode and activated carbon (AC) as the anode is also fabricated, which can deliver a high energy density of 32.9 W h kg -1 at a power density of 229.2 W kg -1 with desirable cycling stability. These electrochemical results evidently indicate the great potential of the sandwich-like rGO/CoNiS x /N-C nanocomposite for applications in high-performance supercapacitors.

Advanced supersonic propulsion study, phases 3 and 4. [variable cycle engines

NASA Technical Reports Server (NTRS)

Allan, R. D.; Joy, W.

1977-01-01

An evaluation of various advanced propulsion concepts for supersonic cruise aircraft resulted in the identification of the double-bypass variable cycle engine as the most promising concept. This engine design utilizes special variable geometry components and an annular exhaust nozzle to provide high take-off thrust and low jet noise. The engine also provides good performance at both supersonic cruise and subsonic cruise. Emission characteristics are excellent. The advanced technology double-bypass variable cycle engine offers an improvement in aircraft range performance relative to earlier supersonic jet engine designs and yet at a lower level of engine noise. Research and technology programs required in certain design areas for this engine concept to realize its potential benefits include refined parametric analysis of selected variable cycle engines, screening of additional unconventional concepts, and engine preliminary design studies. Required critical technology programs are summarized.

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.

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.

Effect of Discharge Rate on Positive Active Material of Lead Carbon Battery for Energy Storage

NASA Astrophysics Data System (ADS)

Chen, Kailun; Liu, Hao; Hu, Chen; Gao, Fei; Yang, Kai; Wang, Hao

2017-10-01

Lead carbon battery has been widespread concern with its excellent performance of charge and discharge under High Rate Part State of Charge (HRPSoC) as well as its cycle performance. In this paper, the cycling performance of lead carbon battery for energy storage was tested by different discharge rate. The effects of different discharge rate on the composition and morphology of positive active materials in the cycle was studied by XRD and SEM. The effect of different discharge rate on the ohmic impedance of lead carbon battery was studied by testing Electrochemical Impedance Spectroscopy with different capacity retention rates. The results show that with the increase of the discharge rate, the content of PbO2 in the positive active material increases, the active substance utilization and the particle size of PbO2 crystal declines, and the ohmic impedance of the battery decreases.

Lithium/disulfide battery R and D

NASA Astrophysics Data System (ADS)

Kaun, T. D.; Deluca, W.; Lee, J.; Redey, L.; Nelson, P. A.

The focus of molten-salt cell R and D in the past year at Argonne National Laboratory has been on developing an understanding of the excellent performance and stability of a lithium/disulfide cell using LiCl-LiBr-KBr electrolyte. For further improvement, we have initiated development of a rod-electrode cell design and design of cells which can tolerate overdischarge and overcharge abuse. Earlier Li/FeS2 cells offered performance quite below expectations and had high capacity decline rates: 0.10 to 0.25 percent per cycle. Approaches for reducing the capacity decline rates of the earlier cells also reduced cell performance. However, our improved Li/FeS2 cell tests indicate good prospects for attaining cell development goals of specific energy of 200 Wh/kg at a 4-h discharge rate, a specific power of 200 W/kg at 80 percent depth of discharge, and a cycle life of 1000 cycles.

Silylated functionalized silicon-based composite as anode with excellent cyclic performance for lithium-ion battery

NASA Astrophysics Data System (ADS)

Li, Xiao; Tian, Xiaodong; Yang, Tao; Wang, Wei; Song, Yan; Guo, Quangui; Liu, Zhanjun

2018-05-01

Inferior cycling stability and rate performance respectively caused by rigorous volume change and poor electrical conductivity were the main challenge of state-of-the-art Silicon-based electrode. In this work, silylated functionalized exfoliated graphite oxide (EGO)/silicon@amorphous carbon (3-APTS-EGO/Si@C) was synthesized by adopting silane as intermediate to connect Si particles with EGO sheets followed by introduction of amorphous carbon. The result suggested that 3-Aminopropyltriethoxysilan connected the EGO sheets and Si nanoparticles via covalent bonds. Owing to the strong covalent interaction and the synergistic effect between the silicon, EGO sheets and amorphous carbon, 3-APTS-EGO/Si@C composite possessed a high capacity of 774 mAh g-1 even after 450 cycles at 0.4 A g-1 with the retention capacity of 97%. This work also provided an effective strategy to improve the long cycling life performance of Si-based electrode.

Charge-discharge characteristics of nickel/zinc battery with polymer hydrogel electrolyte

NASA Astrophysics Data System (ADS)

Iwakura, Chiaki; Murakami, Hiroki; Nohara, Shinji; Furukawa, Naoji; Inoue, Hiroshi

A new nickel/zinc (Ni/Zn) battery was assembled by using polymer hydrogel electrolyte prepared from cross-linked potassium poly(acrylate) and KOH aqueous solution, and its charge-discharge characteristics were investigated. The experimental Ni/Zn cell with the polymer hydrogel electrolyte exhibited well-defined charge-discharge curves and remarkably improved charge-discharge cycle performance, compared to that with a KOH aqueous solution. Moreover, it was found that dendritic growth hardly occurred on the zinc electrode surface during charge-discharge cycles in the polymer hydrogel electrolyte. These results indicate that the polymer hydrogel electrolyte can successfully be used in Ni/Zn batteries as an electrolyte with excellent performance.

Sustainable Interfaces between Si Anodes and Garnet Electrolytes for Room-Temperature Solid-State Batteries.

PubMed

Chen, Cheng; Li, Quan; Li, Yiqiu; Cui, Zhonghui; Guo, Xiangxin; Li, Hong

2018-01-17

Solid-state batteries (SSBs) have seen a resurgence of research interests in recent years for their potential to offer high energy density and excellent safety far beyond current commercialized lithium-ion batteries. The compatibility of Si anodes and Ta-doped Li 7 La 3 Zr 2 O 12 (Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 , LLZTO) solid electrolytes and the stability of the Si anode have been investigated. It is found that Si layer anodes thinner than 180 nm can maintain good contact with the LLZTO plate electrolytes, leading the Li/LLZTO/Si cells to exhibit excellent cycling performance with a capacity retention over 85% after 100 cycles. As the Si layer thickness is increased to larger than 300 nm, the capacity retention of Li/LLZTO/Si cells becomes 77% after 100 cycles. When the thickness is close to 900 nm, the cells can cycle only for a limited number of times because of the destructive volume change at the interfaces. Because of the sustainable Si/LLZTO interfaces with the Si layer anodes with a thickness of 180 nm, full cells with the LiFePO 4 cathodes show discharge capacities of 120 mA h g -1 for LiFePO 4 and 2200 mA h g -1 for the Si anodes at room temperature. They cycle 100 times with a capacity retention of 72%. These results indicate that the combination between the Si anodes and the garnet electrolytes is a promising strategy for constructing high-performance SSBs.

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.

Metal-Organic Framework Derived Porous Hollow Co3O4/N-C Polyhedron Composite with Excellent Energy Storage Capability.

PubMed

Kang, Wenpei; Zhang, Yu; Fan, Lili; Zhang, Liangliang; Dai, Fangna; Wang, Rongming; Sun, Daofeng

2017-03-29

Metal-organic frameworks (MOFs) derived transition metal oxides exhibit enhanced performance in energy conversion and storage. In this work, porous hollow Co 3 O 4 with N-doped carbon coating (Co 3 O 4 /N-C) polyhedrons have been prepared using cobalt-based MOFs as a sacrificial template. Assembled from tiny nanoparticles and N-doped carbon coating, Co 3 O 4 /N-C composite shortens the diffusion length of Li + /Na + ions and possesses an enhanced conductivity. And the porous and hollow structure is also beneficial for tolerating volume changes in the galvanostatic discharge/charge cycles as lithium/sodium battery anode materials. As a result, it can exhibit impressive cycling and rating performance. At 1000 mA g -1 , the specific capacities maintaine stable values of ∼620 mAh g -1 within 2000 cycles as anodes in lithium ion battery, while the specific capacity keeps at 229 mAh g -1 within 150 cycles as sodium ion battery anode. Our work shows comparable cycling performance in lithium ion battery but even better high-rate cycling stability as sodium ion battery anode. Herein, we provide a facile method to construct high electrochemical performance oxide/N-C composite electrode using new MOFs as sacrificial template.

High-performance asymmetric supercapacitors based on multilayer MnO2 /graphene oxide nanoflakes and hierarchical porous carbon with enhanced cycling stability.

PubMed

Zhao, Yufeng; Ran, Wei; He, Jing; Huang, Yizhong; Liu, Zhifeng; Liu, Wei; Tang, Yongfu; Zhang, Long; Gao, Dawei; Gao, Faming

2015-03-18

In this work, MnO(2)/GO (graphene oxide) composites with novel multilayer nanoflake structure, and a carbon material derived from Artemia cyst shell with genetic 3D hierarchical porous structure (HPC), are prepared. An asymmetric supercapacitor has been fabricated using MnO(2)/GO as positive electrode and HPC as negative electrode material. Because of their unique structures, both MnO(2)/GO composites and HPC exhibit excellent electrochemical performances. The optimized asymmetric supercapacitor could be cycled reversibly in the high voltage range of 0-2 V in aqueous electrolyte, which exhibits maximum energy density of 46.7 Wh kg(-1) at a power density of 100 W kg(-1) and remains 18.9 Wh kg(-1) at 2000 W kg(-1). Additionally, such device also shows superior long cycle life along with ∼100% capacitance retention after 1000 cycles and ∼93% after 4000 cycles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bird's nest-like nanographene shell encapsulated Si nanoparticles - Their structural and Li anode properties

NASA Astrophysics Data System (ADS)

Li, Beibei; Jiang, Yizhe; Jiang, Fan; Cao, Daxian; Wang, Hongkang; Niu, Chunming

2017-02-01

Bird's nest-like nanographene shell (NGS) encapsulated Si@SiO2 nanoparticles have been prepared by a simple chemical vapor deposition (CVD) method. The shell is comprised of a conformed coating with 4-10 layers of the nanographene, and nanographene spikes with the same thickness grown on the coating surface. The high crystallinity of the shell is demonstrated by XRD, HRTEM and Raman characterization. After SiO2 has been removed, distinctive void space is created between Si core and nested NGS. Statistical estimation from TEM images of 50 Si@void@NGS particles shows that the volume of void space is about 2.82 times of that of Si nanoparticle, sufficient to accommodate volume change from Si to Li15Si4. Evaluation of Si@void@NGS for Li ion anode reveals a specific capacity of 2634 mAh g-1 at a current density of 0.2 A g-1, and an excellent rate and cycling performance. The capacity decreases by 5.2%-2497 mAh g-1 after cycling at current densities of 0.5, 1, 2, 5 10, 20 A g-1. The excellent performance can be attributed to high conductivity and high stability of the shell, which remains intact after repeated cycling.

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.

Low Temperature Life-Cycle Testing of a Lithium-Ion Battery for Low-Earth-Orbiting Spacecraft

NASA Technical Reports Server (NTRS)

Reid, Concha

2006-01-01

A flight-qualified, lithium-ion (Li-ion) battery developed for the Mars Surveyor Program 2001 Landeris undergoing life-testing at low temperature under a low-Earth-orbit (LEO) profile to assess its capability to provide long term energy storage for aerospace missions. NASA has embarked upon an ambitious course to return humans to the moon by 2015-2020 in preparation for robotic and human exploration of Mars and robotic exploration of the moons of outer planets. Li-ion batteries are excellent candidates to provide power and energy storage for multiple aspects of these missions due to their high specific energy, high energy density, and excellent low temperature performance. Laboratory testing of Li-ion technology is necessary in order to assess lifetime, characterize multi-cell battery-level performance under aerospace conditions, and to gauge safety aspects of the technology. Life-cycle testing provides an opportunity to examine battery-level performance and the dynamics of individual cells in the stack over the entire life of the battery. Data generated through this testing will be critical to establish confidence in the technology for its widespread use in manned and unmanned missions.

[The effects of the processing technic on dentinal adhesion].

PubMed

Krejci, I; Lutz, F; Perisic, U

1992-01-01

In this in vitro study, the effect of application techniques on marginal adaptation of thermal cycled class V restorations restored with an actual dentinal adhesive were quantitated using SEM and dye penetration. Under optimal application conditions, excellent results were generated: though a simple bulk insertion technique was used, no difference was found between enamel and dentin margins before and after thermal loading. On the other hand, contamination of the bonding agent with saliva before composite resin insertion dramatically decreased the percentage of "excellent margin" in dentin and in enamel. Similar effects were found after protecting the bonding agent with an insulating gel. No improvement in marginal adaptation was found after reapplication of the bonding agent. The class V inlay did not show better results than the direct filling technique. However, postcured inlays performed better than their non-postcured counterparts. Without etching enamel with a phosphoric acid gel, but by priming its surface, approximately 80% of "excellent margin" were found in enamel before thermal cycling. This percentage decreased significantly after thermal loading. Restorations totally confined to dentin had slightly lower percentages of "excellent margin" than the mixed class V fillings. The results of this study indicated, that by using dentinal adhesives, little changes and deviations from the correct procedure result in significant alterations in marginal adaptation.

Novel Li[(CF3SO2)(n-C4F9SO2)N]-Based Polymer Electrolytes for Solid-State Lithium Batteries with Superior Electrochemical Performance.

PubMed

Ma, Qiang; Qi, Xingguo; Tong, Bo; Zheng, Yuheng; Feng, Wenfang; Nie, Jin; Hu, Yong-Sheng; Li, Hong; Huang, Xuejie; Chen, Liquan; Zhou, Zhibin

2016-11-02

Solid polymer electrolytes (SPEs) would be promising candidates for application in high-energy rechargeable lithium (Li) batteries to replace the conventional organic liquid electrolytes, in terms of the enhanced safety and excellent design flexibility. Herein, we first report novel perfluorinated sulfonimide salt-based SPEs, composed of lithium (trifluoromethanesulfonyl)(n-nonafluorobutanesulfonyl)imide (Li[(CF 3 SO 2 )(n-C 4 F 9 SO 2 )N], LiTNFSI) and poly(ethylene oxide) (PEO), which exhibit relatively efficient ionic conductivity (e.g., 1.04 × 10 -4 S cm -1 at 60 °C and 3.69 × 10 -4 S cm -1 at 90 °C) and enough thermal stability (>350 °C), for rechargeable Li batteries. More importantly, the LiTNFSI-based SPEs could not only deliver the excellent interfacial compatibility with electrodes (e.g., Li-metal anode, LiFePO 4 and sulfur composite cathodes), but also afford good cycling performances for the Li|LiFePO 4 (>300 cycles at 1C) and Li-S cells (>500 cycles at 0.5C), in comparison with the conventional LiTFSI (Li[(CF 3 SO 2 ) 2 N])-based SPEs. The interfacial impedance and morphology of the cycled Li-metal electrodes are also comparatively analyzed by electrochemical impedance spectra and scanning electron microscopy, respectively. These indicate that the LiTNFSI-based SPEs would be potential alternatives for application in high-energy solid-state Li batteries.

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.

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

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

Construction of reduced graphene oxide supported molybdenum carbides composite electrode as high-performance anode materials for lithium ion batteries

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

Chen, Minghua; Zhang, Jiawei; Chen, Qingguo, E-mail: qgchen@263.net

Highlights: • Reduced graphene oxide supported molybdenum carbides are prepared by two-step strategy. • A unique sheet-on-sheet integrated nanostructure is favorable for fast ion/electron transfer. • The integrated electrode shows excellent Li ion storage performance. - Abstract: Metal carbides are emerging as promising anodes for advanced lithium ion batteries (LIBs). Herein we report reduced graphene oxide (RGO) supported molybdenum carbides (Mo{sub 2}C) integrated electrode by the combination of solution and carbothermal methods. In the designed integrated electrode, Mo{sub 2}C nanoparticles are uniformly dispersed among graphene nanosheets, forming a unique sheet-on-sheet integrated nanostructure. As anode of LIBs, the as-prepared Mo{sub 2}C-RGOmore » integrated electrode exhibits noticeable electrochemical performances with a high reversible capacity of 850 mAh g{sup −1} at 100 mA g{sup −1}, and 456 mAh g{sup −1} at 1000 mA g{sup −1}, respectively. Moreover, the Mo{sub 2}C-RGO integrated electrode shows excellent cycling life with a capacity of ∼98.6 % at 1000 mA g{sup −1} after 400 cycles. Our research may pave the way for construction of high-performance metal carbides anodes of LIBs.« less

Nitrogen-Superdoped 3D Graphene Networks for High-Performance Supercapacitors.

PubMed

Zhang, Weili; Xu, Chuan; Ma, Chaoqun; Li, Guoxian; Wang, Yuzuo; Zhang, Kaiyu; Li, Feng; Liu, Chang; Cheng, Hui-Ming; Du, Youwei; Tang, Nujiang; Ren, Wencai

2017-09-01

An N-superdoped 3D graphene network structure with an N-doping level up to 15.8 at% for high-performance supercapacitor is designed and synthesized, in which the graphene foam with high conductivity acts as skeleton and nested with N-superdoped reduced graphene oxide arogels. This material shows a highly conductive interconnected 3D porous structure (3.33 S cm -1 ), large surface area (583 m 2 g -1 ), low internal resistance (0.4 Ω), good wettability, and a great number of active sites. Because of the multiple synergistic effects of these features, the supercapacitors based on this material show a remarkably excellent electrochemical behavior with a high specific capacitance (of up to 380, 332, and 245 F g -1 in alkaline, acidic, and neutral electrolytes measured in three-electrode configuration, respectively, 297 F g -1 in alkaline electrolytes measured in two-electrode configuration), good rate capability, excellent cycling stability (93.5% retention after 4600 cycles), and low internal resistance (0.4 Ω), resulting in high power density with proper high energy density. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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

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.

2D Frameworks of C2 N and C3 N as New Anode Materials for Lithium-Ion Batteries.

PubMed

Xu, Jiantie; Mahmood, Javeed; Dou, Yuhai; Dou, Shixue; Li, Feng; Dai, Liming; Baek, Jong-Beom

2017-09-01

Novel layered 2D frameworks (C 3 N and C 2 N-450) with well-defined crystal structures are explored for use as anode materials in lithium-ion batteries (LIBs) for the first time. As anode materials for LIBs, C 3 N and C 2 N-450 exhibit unusual electrochemical characteristics. For example, C 2 N-450 (and C 3 N) display high reversible capacities of 933.2 (383.3) and 40.1 (179.5) mAh g -1 at 0.1 and 10 C, respectively. Furthermore, C 3 N shows a low hypothetical voltage (≈0.15 V), efficient operating voltage window with ≈85% of full discharge capacity secured at >0.45 V, and excellent cycling stability for more than 500 cycles. The excellent electrochemical performance (especially of C 3 N) can be attributed to their inherent 2D polyaniline frameworks, which provide large net positive charge densities, excellent structural stability, and enhanced electronic/ionic conductivity. Stable solid state interface films also form on the surfaces of the 2D materials during the charge/discharge process. These 2D materials with promising electrochemical performance should provide insights to guide the design and development of their analogues for future energy applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advanced cathode materials for high-power applications

NASA Astrophysics Data System (ADS)

Amine, K.; Liu, J.; Belharouak, I.; Kang, S.-H.; Bloom, I.; Vissers, D.; Henriksen, G.

In our efforts to develop low cost high-power Li-ion batteries with excellent safety, as well as long cycle and calendar life, lithium manganese oxide spinel and layered lithium nickel cobalt manganese oxide cathode materials were investigated. Our studies with the graphite/LiPF 6/spinel cells indicated a very significant degradation of capacity with cycling at 55 °C. This degradation was caused by the reduction of manganese ions on the graphite surface which resulted in a significant increase of the charge-transfer impedance at the anode/electrolyte interface. To improve the stability of the spinel, we investigated an alternative salt that would not generate HF acid that may attack the spinel. The alternative salt we selected for this work was lithium bisoxalatoborate, LiB(C 2O 4) 2 ("LiBoB"). In this case, the graphite/LiBoB/spinel Li-ion cells exhibited much improved cycle/calendar life at 55 °C and better abuse tolerance, as well as excellent power. A second system based on LiNi 1/3Co 1/3Mn 1/3O 2 layered material was also investigated and its performance was compared to commercial LiNi 0.8Co 0.15Al 0.05O 2. Cells based on LiNi 1/3Co 1/3Mn 1/3O 2 showed lower power fade and better thermal safety than the LiNi 0.8Co 0.15Al 0.05O 2-based commercial cells under similar test conditions. Li-ion cells based on the material with excess lithium (Li 1.1Ni 1/3Co 1/3Mn 1/3O 2) exhibited excellent power performance that exceeded the FreedomCAR requirements.

A combined theoretical and experimental study on the oxygenated graphitic carbon nitride as a promising sulfur host for lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

He, Feng; Li, Kai; Yin, Cong; Ding, Yingchun; Tang, Hao; Wang, Ying; Wu, Zhijian

2018-01-01

To effectively restrain the dissolution of soluble polysulfides and fully utilize the active sulfur materials in lithium-sulfur (Li-S) batteries, host materials with unique compositions and porous structures have been pursued. Herein, we have investigated the mechanism of the excellent activity of oxygenated g-C3N4 for Li-S batteries from theoretical perspective, and the further experiment confirms that our O-g-C3N4-S cathode exhibits much better electrochemical performance compared with those in previous reports. Our DFT calculations reveal that the oxygenated material has better electrical conductivity and stronger adsorption ability with the Li2Sx species compared with the pristine g-C3N4 and other two-dimensional (2D) materials. Furthermore, we have confirmed experimentally that the O-g-C3N4-S composite cathode exhibits excellent electrochemical performance in Li-S batteries with high reversible discharge capacity of 1030 mAh g-1 after 100 cycles at 0.2 C, great rate capability with the discharge capacity of 364 mAh g-1 even at 5.0 C, and outstanding long-term cyclic stability with the discharge capacity of 465 mAh g-1 after 1000 cycles at 1.0 C (capacity decay was only 0.046% per cycle). Our results also suggest that theoretical study will play a significant role in predicting and screening novel materials with better performance.

A facile route to modify ferrous phosphate and its use as an iron-containing resource for LiFePO4 via a polyol process.

PubMed

Li, Shaomin; Liu, Xichuan; Mi, Rui; Liu, Hao; Li, Yinchuan; Lau, Woon-min; Mei, Jun

2014-06-25

This study introduces an economical and environmentally friendly way of synthesizing LiFePO4/C to be used as cathode material in lithium ion batteries via two processes: (1) the synthesis of LiFePO4/C cathode material using a low cost divalent precursor ferrous phosphate, Fe3 (PO4)2·8H2O, as iron source in a polyol process and (2) the modification of the morphology of this precursor by varying the reaction time in a coprecipitation process. The study examines the effects of different structures and morphologies of the precursor on the structure and electrochemical performance of the as-synthesized LiFePO4/C. The LiFePO4/C shows an excellent rate capability and cycle performance, with initial discharge capacities of 153, 128, and 106 mA h g(-1) at 1 C, 5 C, and 10 C. The capacity retention is respectively 98.7%, 98.2%, and 98.7%, after 10 cycles at the corresponding rates. The capacity retention remains at 97% even after 300 cycles at the rate of 10 C. The outstanding electrochemical performance can be attributed to the improved rate of Li(+) diffusion and the excellent crystallinity of synthesized LiFePO4/C powders through the modified precursor. Therefore, this is an economical and environmentally friendly way of synthesizing LiFePO4/C to be used as cathode material in lithium ion batteries.

Electrospray-deposition of graphene electrodes: a simple technique to build high-performance supercapacitors.

PubMed

Tang, Huaichao; Yang, Cheng; Lin, Ziyin; Yang, Quanhong; Kang, Feiyu; Wong, Ching Ping

2015-05-28

Here we report an electrostatic spray deposition method to prepare three-dimensional porous graphene electrodes for supercapacitor applications. The symmetric supercapacitor exhibits excellent specific capacitance (366 F g(-1) at 1 A g(-1) in 6 M KOH) and long cycle life (108% capacitance retention up to 40 000 cycles). Moreover, the energy densities of the organic and aqueous electrolyte based supercapacitors reach 22.9 and 8.1 Wh kg(-1) when the power densities are 119.2 and 15.4 kW kg(-1), respectively. Compared with the previously reported graphene based supercapacitors, the improved properties could be attributed to the excellent three-dimensional open porous electrode structure, which is favorable for the ion diffusion and electron transport. In addition, this method provides a simple electrode-fabrication route without the involvement of conducting additives and binders. It may find vast applications in thin and miniaturized energy storage scenarios.

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.

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

Novel lithium titanate-graphene hybrid containing two graphene conductive frameworks for lithium-ion battery with excellent electrochemical performance

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

Ruiyi, Li; Tengyuan, Chen; Beibei, Sun

Graphical abstract: We developed a new Novel lithium titanate-graphene nanohybrid containing two graphene conductive frameworks. The unique architecture creates fast electron transfer and rapid mass transport of electrolyte. The hybrid electrode provides excellent electrochemical performances for lithium-ion batteries, including high specific capacity, outstanding rate capability and intriguing cycling stability. - Highlights: • We reported a new LTO-graphene nanohybrid containing two graphene conductive frameworks. • One graphene framework greatly improves the electrical conductivity of LTO crystal. • Another graphene framework enhances electrical conductivity of between LTO crystals and electrolyte transport. • The unique architecture creates big tap density, ultrafast electron transfermore » and rapid mass transport. • The hybrid electrode provides excellent electrochemical performance for lithium-ion batteries. - ABSTRACT: The paper reported the synthesis of lithium titanate(LTO)-graphene hybrid containing two graphene conductive frameworks (G@LTO@G). Tetrabutyl titanate and graphene were dispersed in tertbutanol and heated to reflux state by microwave irradiation. Followed by adding lithium acetate to produce LTO precursor/graphene (p-LTO/G). The resulting p-LTO/G offers homogeneous morphology and ultra small size. All graphene sheets were buried in the spherical agglomerates composed of primitive particles through the second agglomeration. The p-LTO/G was calcined to LTO@graphene (LTO@G). To obtain G@LTO@G, the LTO@G was further hybridized with graphene. The as-prepared G@LTO@G shows well-defined three-dimensional structure and hierarchical porous distribution. Its unique architecture creates big tap density, fast electron transfer and rapid electrolyte transport. As a result, the G@LTO@G provides high specific capacity (175.2 mA h g{sup −1} and 293.5 mA cm{sup −3}), outstanding rate capability (155.7 mAh g{sup −1} at 10C) and intriguing cycling stability (97.2% capacity retention at 5C after 1000 cycles)« less

Supercapacitors based on 3D network of activated carbon nanowhiskers wrapped-on graphitized electrospun nanofibers

NASA Astrophysics Data System (ADS)

He, Shuijian; Chen, Linlin; Xie, Chencheng; Hu, Huan; Chen, Shuiliang; Hanif, Muddasir; Hou, Haoqing

2013-12-01

Due to their cycling stability and high power density, the supercapacitors bridge the power/energy gap between traditional dielectric capacitors and batteries/fuel cells. Electrode materials are key components for making high performance supercapacitors. An activated carbon nanowhiskers (ACNWs) wrapped-on graphitized electrospun nanofiber (GENF) network (ACNWs/GENFN) with 3D porous structure is prepared as a new type of binder-free electrode material for supercapacitors. The supercapacitor based on the ACNWs/GENFN composite material displays an excellent performance with a specific capacitance of 176.5 F g-1 at current density of 0.5 A g-1, an ultrahigh power density of 252.8 kW kg-1 at current density of 800 A g-1 and an outstanding cycling stability of no capacitance loss after 10,000 charge/discharge cycles.

Nanosheets of earth-abundant jarosite as novel anodes for high-rate and long-life lithium-ion batteries.

PubMed

Ding, Yuan-Li; Wen, Yuren; Chen, Chia-Chin; van Aken, Peter A; Maier, Joachim; Yu, Yan

2015-05-20

Nanosheets of earth-abundant jarosite were fabricated via a facile template-engaged redox coprecipitation strategy at room temperature and employed as novel anode materials for lithium-ion batteries (LIBs) for the first time. These 2D materials exhibit high capacities, excellent rate capability, and prolonged cycling performance. As for KFe3(SO4)2(OH)6 jarosite nanosheets (KNSs), the reversible capacities of above 1300 mAh g(-1) at 100 mA g(-1) and 620 mAh g(-1) after 4000 cycles at a very high current density of 10 A g(-1) were achieved, respectively. Moreover, the resulting 2D nanomaterials retain good structural integrity upon cycling. These results reveal great potential of jarosite nanosheets as low-cost and high-performance anode materials for next-generation LIBs.

Self-Assembled Hierarchical Formation of Conjugated 3D Cobalt Oxide Nanobead-CNT-Graphene Nanostructure Using Microwaves for High-Performance Supercapacitor Electrode.

PubMed

Kumar, Rajesh; Singh, Rajesh Kumar; Dubey, Pawan Kumar; Singh, Dinesh Pratap; Yadav, Ram Manohar

2015-07-15

Here we report the electrochemical performance of a interesting three-dimensional (3D) structures comprised of zero-dimensional (0D) cobalt oxide nanobeads, one-dimensional (1D) carbon nanotubes and two-dimensional (2D) graphene, stacked hierarchically. We have synthesized 3D self-assembled hierarchical nanostructure comprised of cobalt oxide nanobeads (Co-nb), carbon nanotubes (CNTs), and graphene nanosheets (GNSs) for high-performance supercapacitor electrode application. This 3D self-assembled hierarchical nanostructure Co3O4 nanobeads-CNTs-GNSs (3D:Co-nb@CG) is grown at a large scale (gram) through simple, facile, and ultrafast microwave irradiation (MWI). In 3D:Co-nb@CG nanostructure, Co3O4 nanobeads are attached to the CNT surfaces grown on GNSs. Our ultrafast, one-step approach not only renders simultaneous growth of cobalt oxide and CNTs on graphene nanosheets but also institutes the intrinsic dispersion of carbon nanotubes and cobalt oxide within a highly conductive scaffold. The 3D:Co-nb@CG electrode shows better electrochemical performance with a maximum specific capacitance of 600 F/g at the charge/discharge current density of 0.7A/g in KOH electrolyte, which is 1.56 times higher than that of Co3O4-decorated graphene (Co-np@G) nanostructure. This electrode also shows a long cyclic life, excellent rate capability, and high specific capacitance. It also shows high stability after few cycles (550 cycles) and exhibits high capacitance retention behavior. It was observed that the supercapacitor retained 94.5% of its initial capacitance even after 5000 cycles, indicating its excellent cyclic stability. The synergistic effect of the 3D:Co-nb@CG appears to contribute to the enhanced electrochemical performances.

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

Nanostructured LiMn2O4 composite as high-rate cathode for high performance aqueous Li-ion hybrid supercapacitors

NASA Astrophysics Data System (ADS)

Chen, Lina; Zhai, Wei; Chen, Long; Li, Deping; Ma, Xiaoxin; Ai, Qing; Xu, Xiaoyan; Hou, Guangmei; Zhang, Lin; Feng, Jinkui; Si, Pengchao; Ci, Lijie

2018-07-01

Nanostructured spinel LiMn2O4 and super P composite with much enhanced electrochemical performance especially ultrahigh rate capability as the cathode for aqueous hybrid supercapacitors is synthesized by ball milling commercial LiMn2O4 particles together with super P. The as-prepared composite delivers a high capacitance of 306 F g-1 at the current density of 1 A g-1 and superb rate ability of 228.6 F g-1 at 40 A g-1 in 1 M Li2SO4 aqueous electrolyte. The capacitance of the nanostructured composite is 3.5 times higher than that of pristine LiMn2O4 even being charged and discharged 80 times faster. The excellent performances are ascribed to the nanosized LiMn2O4 well dispersed into the conductive carbon matrix. LiMn2O4 and super P composite//active carbon hybrid supercapacitor is assembled and the energy density can reach up to 21.58 Wh kg-1 at 293.16 W kg-1 and 13 Wh kg-1 at 5200 W kg-1. The hybrid device also shows an excellent cycling performance, which retains 85% of the initial capacitance after 4500 cycles. This work provides an effectively facile way to produce high performance LiMn2O4-based cathodes for hybrid suercapacitors in practical applications.

Amorphous Zn₂GeO₄ Nanoparticles as Anodes with High Reversible Capacity and Long Cycling Life for Li-ion Batteries

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

Yi, Ran; Feng, Jinkui; Lv, Dongping

2013-07-30

Amorphous and crystalline Zn₂GeO₄ nanoparticles were prepared and characterized as anode materials for Li-ion batteries. A higher reversible specific capacity of 1250 mAh/g after 500 cycles and excellent rate capability were obtained for amorphous Zn₂GeO₄ nanoparticles, compared to that of crystalline Zn₂GeO₄ nanoparticles. Small particle size, amorphous phase and incorporation of zinc and oxygen contribute synergetically to the improved performance by effectively mitigating the huge volume variations during lithiation and delithiation process.

Simulation and experiment of thermal fatigue in the CPV die attach

NASA Astrophysics Data System (ADS)

Bosco, Nick; Silverman, Timothy; Kurtz, Sarah

2012-10-01

FEM simulation and accelerated thermal cycling have been performed for the CPV die attach. Trends in fatigue damage accumulation and equivalent test time are explored and found to be most sensitive to temperature ramp rate. Die attach crack growth is measured through cycling and found to be in excellent agreement with simulations of the inelastic strain energy accumulated. Simulations of an entire year of weather data provides for the relative ranking of fatigue damage between four cities as well as their equivalent accelerated test time.

A high-performance nanoporous Si/Al2O3 foam lithium-ion battery anode fabricated by selective chemical etching of the Al-Si alloy and subsequent thermal oxidation.

PubMed

Hwang, Gaeun; Park, Hyungmin; Bok, Taesoo; Choi, Sinho; Lee, Sungjun; Hwang, Inchan; Choi, Nam-Soon; Seo, Kwanyong; Park, Soojin

2015-03-14

Nanostructured micrometer-sized Al-Si particles are synthesized via a facile selective etching process of Al-Si alloy powder. Subsequent thin Al2O3 layers are introduced on the Si foam surface via a selective thermal wet oxidation process of etched Al-Si particles. The resulting Si/Al2O3 foam anodes exhibit outstanding cycling stability (a capacity retention of 78% after 300 cycles at the C/5 rate) and excellent rate capability.

Green synthesis of layered 1T-MoS2/reduced graphene oxide nanocomposite with excellent catalytic performances for 4-nitrophenol reduction

NASA Astrophysics Data System (ADS)

Meng, Nannan; Cheng, Jian; Zhou, Yifeng; Nie, Wangyan; Chen, Pengpeng

2017-02-01

A green and facile process was developed to prepare layered octahedral phase MoS2/reduced graphene oxide (1T-MoS2/RGO) nanocomposite by a Vitamin C-assisted self-assemble method, in which graphene oxide (GO) and LiMoS2 were used as starting materials. Catalytic performances of 1T-MoS2/RGO were evaluated by hydrogenation of 4-nitrophenol (4-NP). It was demonstrated that the prepared 1T-MoS2/RGO nanocomposite presented excellent catalytic performance and cycling stability for 4-NP reduction, which made it a promising noble-metal-free catalyst. Additionally, broadening work suggested some other RGO-based metal nanocomposite with well-defined porous structure could be also generated via this facile self-assembly method.

Scalable synthesis of nano-silicon from beach sand for long cycle life Li-ion batteries.

PubMed

Favors, Zachary; Wang, Wei; Bay, Hamed Hosseini; Mutlu, Zafer; Ahmed, Kazi; Liu, Chueh; Ozkan, Mihrimah; Ozkan, Cengiz S

2014-07-08

Herein, porous nano-silicon has been synthesized via a highly scalable heat scavenger-assisted magnesiothermic reduction of beach sand. This environmentally benign, highly abundant, and low cost SiO₂ source allows for production of nano-silicon at the industry level with excellent electrochemical performance as an anode material for Li-ion batteries. The addition of NaCl, as an effective heat scavenger for the highly exothermic magnesium reduction process, promotes the formation of an interconnected 3D network of nano-silicon with a thickness of 8-10 nm. Carbon coated nano-silicon electrodes achieve remarkable electrochemical performance with a capacity of 1024 mAhg(-1) at 2 Ag(-1) after 1000 cycles.

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.

Mesoporous Germanium Anode Materials for Lithium-Ion Battery with Exceptional Cycling Stability in Wide Temperature Range.

PubMed

Choi, Sinho; Cho, Yoon-Gyo; Kim, Jieun; Choi, Nam-Soon; Song, Hyun-Kon; Wang, Guoxiu; Park, Soojin

2017-04-01

Porous structured materials have unique architectures and are promising for lithium-ion batteries to enhance performances. In particular, mesoporous materials have many advantages including a high surface area and large void spaces which can increase reactivity and accessibility of lithium ions. This study reports a synthesis of newly developed mesoporous germanium (Ge) particles prepared by a zincothermic reduction at a mild temperature for high performance lithium-ion batteries which can operate in a wide temperature range. The optimized Ge battery anodes with the mesoporous structure exhibit outstanding electrochemical properties in a wide temperature ranging from -20 to 60 °C. Ge anodes exhibit a stable cycling retention at various temperatures (capacity retention of 99% after 100 cycles at 25 °C, 84% after 300 cycles at 60 °C, and 50% after 50 cycles at -20 °C). Furthermore, full cells consisting of the mesoporous Ge anode and an LiFePO 4 cathode show an excellent cyclability at -20 and 25 °C. Mesoporous Ge materials synthesized by the zincothermic reduction can be potentially applied as high performance anode materials for practical lithium-ion batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Superior performance of nanoscaled Fe3O4 as anode material promoted by mosaicking into porous carbon framework

NASA Astrophysics Data System (ADS)

Wan, Wang; Wang, Chao; Zhang, Weidong; Chen, Jitao; Zhou, Henghui; Zhang, Xinxiang

2014-01-01

A nanoscale Fe3O4/porous carbon-multiwalled carbon nanotubes (MWCNTs) composite is synthesized through a simple hard-template method by using Fe2O3 nanoparticles as the precursor and SiO2 nanoparticles as the template. The composite shows good cycle performance (941 mAh g-1 for the first cycle at 0.1 C, with 106% capacity retention at the 80th cycle) and high rate capability (71% capacity retained at 5 C rate). Its excellent electrical properties can be attributed to the porous carbon framework structure, which is composed of carbon and MWCNTs. In this composite, the porous structure provides space for the change in Fe3O4 volume during cycling and shortens the lithium ion diffusion distance, the MWCNTs increase the electron conductivity, and the carbon coating reduces the risk of side reactions. The results provide clear evidences for the utility of porous carbon framework to improve the electrochemical performances of nanosized transition-metal oxides as anode materials for lithium-ion batteries.

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.

Interfacial Engineered Polyaniline/Sulfur-Doped TiO2 Nanotube Arrays for Ultralong Cycle Lifetime Fiber-Shaped, Solid-State Supercapacitors.

PubMed

Li, Chun; Wang, Zhuanpei; Li, Shengwen; Cheng, Jianli; Zhang, Yanning; Zhou, Jingwen; Yang, Dan; Tong, Dong-Ge; Wang, Bin

2018-05-30

Fiber-shaped supercapacitors (FSCs) have great promises in wearable electronics applications. However, the limited specific surface area and inadequate structural stability caused by the weak interfacial interactions of the electrodes result in relatively low specific capacitance and unsatisfactory cycle lifetime. Herein, solid-state FSCs with high energy density and ultralong cycle lifetime based on polyaniline (PANI)/sulfur-doped TiO 2 nanotube arrays (PANI/S-TiO 2 ) are fabricated by interfacial engineering. The experimental results and ab initio calculations reveal that S doping can effectively promote the conductivity of titania nanotubes and increase the binding energy of PANI anchored on the electrode surface, leading to a much stronger binding of PANI on the surface of the electrode and excellent electrode structure stability. As a result, the FSCs using the PANI/S-TiO 2 electrodes deliver a high specific capacitance of 91.9 mF cm -2 , a capacitance retention of 93.78% after 12 000 charge-discharge cycles, and an areal energy density of 3.2 μW h cm -2 . Meanwhile, the all-solid-state FSC device retains its excellent flexibility and stable electrochemical capacitance even after bending 150 cycles. The enhanced performances of FSCs could be attributed to the large surface area, reduced ion diffusion path, improved electrical conductivity, and engineered interfacial interaction of the rationally designed electrodes.

Quantification of cell cycle kinetics by EdU (5-ethynyl-2′-deoxyuridine)-coupled-fluorescence-intensity analysis

PubMed Central

Cabrita, Marisa; Bekman, Evguenia; Braga, José; Rino, José; Santus, Renè; Filipe, Paulo L.; Sousa, Ana E.; Ferreira, João A.

2017-01-01

We propose a novel single-deoxynucleoside-based assay that is easy to perform and provides accurate values for the absolute length (in units of time) of each of the cell cycle stages (G1, S and G2/M). This flow-cytometric assay takes advantage of the excellent stoichiometric properties of azide-fluorochrome detection of DNA substituted with 5-ethynyl-2′-deoxyuridine (EdU). We show that by pulsing cells with EdU for incremental periods of time maximal EdU-coupled fluorescence is reached when pulsing times match the length of S phase. These pulsing times, allowing labelling for a full S phase of a fraction of cells in asynchronous populations, provide accurate values for the absolute length of S phase. We characterized additional, lower intensity signals that allowed quantification of the absolute durations of G1 and G2 phases. Importantly, using this novel assay data on the lengths of G1, S and G2/M phases are obtained in parallel. Therefore, these parameters can be estimated within a time frame that is shorter than a full cell cycle. This method, which we designate as EdU-Coupled Fluorescence Intensity (E-CFI) analysis, was successfully applied to cell types with distinctive cell cycle features and shows excellent agreement with established methodologies for analysis of cell cycle kinetics. PMID:28465489

Flexible Carbon Nanotube Modified Separator for High-Performance Lithium-Sulfur Batteries

PubMed Central

Liu, Bin; Wu, Xiaomeng; Wang, Shan; Tang, Zhen; Yang, Quanling; Hu, Guo-Hua; Xiong, Chuanxi

2017-01-01

Lithium-sulfur (Li-S) batteries have become promising candidates for electrical energy storage systems due to their high theoretical specific energy density, low cost and environmental friendliness. However, there are some technical obstacles of lithium-sulfur batteries to be addressed, such as the shuttle effect of polysulfides. Here, we introduced organically modified carbon nanotubes (CNTs) as a coating layer for the separator to optimize structure and enhance the performance of the Li-S battery. The results showed that the cell with a CNTs-coated separator exhibited an excellent cycling performance. Compared to the blank separator, the initial discharge capacity and the capacity after 100 cycles for the CNTs-coated separator was increased by 115% and 161%, respectively. Besides, according to the rate capability test cycling from 0.1C to 2C, the battery with a CNTs-coated separator still released a capacity amounting to 90.2% of the initial capacity, when the current density returned back to 0.1C. It is believed that the organically modified CNTs coating effectively suppresses the shuttle effect during the cycling. The employment of a CNTs-coated separator provides a promising approach for high-performance lithium-sulfur batteries. PMID:28933721

Plasma-assisted nitrogen doping of VACNTs for efficiently enhancing the supercapacitor performance

NASA Astrophysics Data System (ADS)

Mashayekhi, Alireza; Hosseini, Seyed Mahmoud; Hassanpour Amiri, Morteza; Namdar, Naser; Sanaee, Zeinab

2016-06-01

Nitrogen doping of vertically aligned carbon nanotubes (VACNTs) using plasma-enhanced chemical vapour deposition has been investigated to improve the supercapacitance performance of CNTs. Incorporating electrochemical measurements on the open-ended nitrogen-doped CNTs, showed the achievement of 6 times improvement in the capacitance value. For nitrogen-doped CNTs on silicon substrate, specific capacitance of 60 F g-1 was obtained in 0.5 M KCl solution, with capacity retention ratio above 90 % after cycled at 0.1 A g-1 for 5000 cycles. Using this sample, a symmetric supercapacitance was fabricated which showed the power density of 37.5 kW kg-1. The facile fabrication approach and its excellent capacitance improvement, propose it as an efficient technique for enhancing the supercapacitance performance of the carbon-based electrodes.

Nitrogen-doped biomass/polymer composite porous carbons for high performance supercapacitor

NASA Astrophysics Data System (ADS)

Shu, Yu; Maruyama, Jun; Iwasaki, Satoshi; Maruyama, Shohei; Shen, Yehua; Uyama, Hiroshi

2017-10-01

Nitrogen-doped porous monolithic carbon (NDPMC) is obtained from biomass-derived activated carbon/polyacrylonitrile composite for the first time via a template-free thermally induced phase separation (TIPS) approach followed by KOH activation. The electrochemical results indicate that NDPMC possesses ultrahigh specific capacitance of 442 F g-1 at 1 A g-1, excellent rate capability with 81% retention rate from 1 to 100 A g-1 and outstanding cycling stability with 98% capacitance retention at 20 A g-1 after 5000 cycles. Furthermore, the evaluation of NDPMC on the practical symmetrical system also exhibits desired electrochemical performances. The novel composite carbon displays remarkable capacitance properties and the feasible, low-cost synthetic route demonstrates great potential for large-scale production of high-performance electrode materials for supercapacitors.

OAO-3 end of mission power subsystem evaluation

NASA Technical Reports Server (NTRS)

Tasevoli, M.

1982-01-01

End of mission tests were performed on the OAO-3 power subsystem in three component areas: solar array, nickel-cadmium batteries and the On-Board Processor (OBP) power boost operation. Solar array evaluation consisted of analyzing array performance characteristics and comparing them to earlier flight data. Measured solar array degradation of 14.1 to 17.7% after 8 1/3 years is in good agreement with theortical radiation damage losses. Battery discharge characteristics were compared to results of laboratory life cycle tests performed on similar cells. Comparison of cell voltage profils reveals close correlation and confirms the validity of real time life cycle simulation. The successful operation of the system in the OBP/power boost regulation mode demonstrates the excellent life, reliability and greater system utilization of power subsystems using maximum power trackers.

Galvanic displacement assembly of ultrathin Co3O4 nanosheet arrays on nickel foam for a high-performance supercapacitor

NASA Astrophysics Data System (ADS)

You, Yuxiu; Zheng, Maojun; Ma, Liguo; Yuan, Xiaoliang; Zhang, Bin; Li, Qiang; Wang, Faze; Song, Jingnan; Jiang, Dongkai; Liu, Pengjie; Ma, Li; Shen, Wenzhong

2017-03-01

High-performance supercapacitors are very desirable for many portable electronic devices, electric vehicles and high-power electronic devices. Herein, a facile and binder-free synthesis method, galvanic displacement of the precursor followed by heat treatment, is used to fabricate ultrathin Co3O4 nanosheet arrays on nickel foam substrate. When used as a supercapacitor electrode the prepared Co3O4 on nickel foam exhibits a maximum specific capacitance of 1095 F g-1 at a current density of 1 A g-1 and good cycling stability of 71% retention after 2000 cycling tests. This excellent electrochemical performance can be ascribed to the high specific surface area of each Co3O4 nanosheet that comprises numerous nanoparticles.

Electrode-Impregnable and Cross-Linkable Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Polymer Electrolytes with High Ionic Conductivity and a Large Voltage Window for Flexible Solid-State Supercapacitors.

PubMed

Han, Jae Hee; Lee, Jang Yong; Suh, Dong Hack; Hong, Young Taik; Kim, Tae-Ho

2017-10-04

We present cross-linkable precursor-type gel polymer electrolytes (GPEs) that have large ionic liquid uptake capability, can easily penetrate electrodes, have high ion conductivity, and are mechanically strong as high-performance, flexible all-solid-state supercapacitors (SC). Our polymer precursors feature a hydrophilic-hydrophobic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock main-chain structure and trifunctional silane end groups that can be multi-cross-linked with each other through a sol-gel process. The cross-linked solid-state electrolyte film with moderate IL content (200 wt %) shows a well-balanced combination of excellent ionic conductivity (5.0 × 10 -3 S cm -1 ) and good mechanical stability (maximum strain = 194%). Moreover, our polymer electrolytes have various advantages including high thermal stability (decomposition temperature > 330 °C) and the capability to impregnate electrodes to form an excellent electrode-electrolyte interface due to the very low viscosity of the precursors. By assembling our GPE-impregnated electrodes and solid-state GPE film, we demonstrate an all-solid-state SC that can operate at 3 V and provides an improved specific capacitance (112.3 F g -1 at 0.1 A g -1 ), better rate capability (64% capacity retention until 20 A g -1 ), and excellent cycle stability (95% capacitance decay over 10 000 charge/discharge cycles) compared with those of a reference SC using a conventional PEO electrolyte. Finally, flexible SCs with a high energy density (22.6 W h kg -1 at 1 A g -1 ) and an excellent flexibility (>93% capacitance retention after 5000 bending cycles) can successfully be obtained.

Nanocrystalline LaOx/NiO composite as high performance electrodes for supercapacitors.

PubMed

Du, Guo; Zeng, Zifan; Xiao, Bangqing; Wang, Dengzhi; Yuan, Yuan; Zhu, Xiaohong; Zhu, Jiliang

2017-12-21

Nanocrystalline LaO x /NiO composite electrodes were synthesized via two types of facile cathodic electrodeposition methods onto nickel foam followed by thermal annealing without any binders. Scanning electron microscopy and transmission electron microscopy investigation revealed that LaO x nanocrystalline particles with an average diameter of 50 nm are uniformly distributed in the NiO layer or alternately deposited with the NiO layer onto the substrate. It is speculated that LaO x particles can participate in the faradaic reaction directly and offer more redox sites. Besides this, the unique Ni/La layered structure facilitates the diffusion of ions and retards the electrode polarization, thus leading to a better rate capability and cycling stability of NiO. As a result, the obtained electrodes display very competitive electrochemical performance (a specific capacitance of 1238 F g -1 at a current density of 0.5 A g -1 , excellent rate capability of 86% of the original capacitance at 10 A g -1 and excellent cycling stability of 93% capacitance after 10 000 cycles). In addition, asymmetric coin devices were assembled using LaO x /NiO as the positive electrode and active carbon as the negative electrode. The assembled asymmetric devices demonstrate a high energy density of 13.12 W h kg -1 at a power density of 90.72 W kg -1 .

Reliability Testing of NASA Piezocomposite Actuators

NASA Technical Reports Server (NTRS)

Wilkie, W.; High, J.; Bockman, J.

2002-01-01

NASA Langley Research Center has developed a low-cost piezocomposite actuator which has application for controlling vibrations in large inflatable smart space structures, space telescopes, and high performance aircraft. Tests show the NASA piezocomposite device is capable of producing large, directional, in-plane strains on the order of 2000 parts-per-million peak-to-peak, with no reduction in free-strain performance to 100 million electrical cycles. This paper describes methods, measurements, and preliminary results from our reliability evaluation of the device under externally applied mechanical loads and at various operational temperatures. Tests performed to date show no net reductions in actuation amplitude while the device was moderately loaded through 10 million electrical cycles. Tests were performed at both room temperature and at the maximum operational temperature of the epoxy resin system used in manufacture of the device. Initial indications are that actuator reliability is excellent, with no actuator failures or large net reduction in actuator performance.

A Host-Configured Lithium-Sulfur Cell Built on 3D Nickel Photonic Crystal with Superior Electrochemical Performances.

PubMed

Lin, Shengxuan; Yan, Yang; Cai, Zihe; Liu, Lin; Hu, Xiaobin

2018-04-18

The insulator of the sulfur cathode and the easy dendrites growth of the lithium anode are the main barriers for lithium-sulfur cells in commercial application. Here, a 3D NPC@S/3D NPC@Li full cell is reported based on 3D hierarchical and continuously porous nickel photonic crystal (NPC) to solve the problems of sulfur cathode and lithium anode at the same time. In this case, the 3D NPC@S cathode can not only offer a fast transfer of electron and lithium ion, but also effectively prevent the dissolution of polysulfides and the tremendous volume change during cycling, and the 3D NPC@Li anode can efficiently inhibit the growth of lithium dendrites and volume expansion, too. As a result, the cell exhibits a high reversible capacity of 1383 mAh g -1 at 0.5 C (the current density of 837 mA g -1 ), superior rate ability (the reversible capacity of 735 mAh g -1 at the extremely high current density of 16 750 mA g -1 ) with excellent coulombic efficiency of about 100% and an excellent cycle life over 500 cycles with only about 0.026% capacity loss per cycle. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Construction of Metal-Organic Framework/Conductive Polymer Hybrid for All-Solid-State Fabric Supercapacitor.

PubMed

Qi, Kai; Hou, Ruizuo; Zaman, Shahid; Qiu, Yubing; Xia, Bao Yu; Duan, Hongwei

2018-05-30

Metal-organic frameworks (MOFs) hold promising potential in energy storage but are limited by poor conductivity. In this work, a metal-organic framework/polypyrrole hybrid is constructed by a facile one-pot electrodeposition method in the presence of dopamine. An all-solid-state fabric supercapacitor based on this hybrid demonstrates excellent electrochemical energy-storage performance, which achieves a specific capacitance of 10 mF cm -1 (206 mF cm -2 ), a power density of 132 μW cm -1 (2102 μW cm -2 ), and an energy density of 0.8 μWh cm -1 (12.8 μWh cm -2 ). The stable cycling life and excellent mechanical flexibility over a wide range of working temperature are also achieved, which maintains a capacitance retention of 89% over 10 000 charging/discharging cycles, a capacitance decrease of only 4% after 1000 frizzy (360° bending) cycles, and no obvious capacitance loss under 100 repeated heating (100 °C)/cooling (-15 °C) cycles. This fibrous supercapacitor displays promising potential in wearable textile electronics as it can be easily woven into common cotton cloth. Our strategy may shed some valuable light on the construction of MOF-based hybrids for flexible energy-storage electronics.

3D porous and ultralight carbon hybrid nanostructure fabricated from carbon foam covered by monolayer of nitrogen-doped carbon nanotubes for high performance supercapacitors

NASA Astrophysics Data System (ADS)

He, Shuijian; Hou, Haoqing; Chen, Wei

2015-04-01

3D porous and self-supported carbon hybrids are promising electrode materials for supercapacitor application attributed to their prominent properties such as binder-free electrode fabrication process, excellent electric conductivity and high power density etc. We present here a facile chemical vapor deposition method to fabricate a novel 3D flexible carbon hybrid nanostructure by growing a monolayer of nitrogen-doped carbon nanotubes on the skeleton of carbon foam (N-CNTs/CF) with Fe nanoparticle as catalyst. With such 3D porous, flexible and ultralight carbon nanostructure as binder-free electrode material, large surface area is available and fast ionic transport is facilitated. Moreover, the carbon-based network can provide excellent electronic conductivity. The electrochemical studies demonstrate that the supercapacitor constructed from the N-CNTs/CF hybrid exhibit high power density of 69.3 kW kg-1 and good stability with capacitance retention ration above 95% after cycled at 50 A g-1 for 5000 cycles. Therefore, the prepared porous N-CNTs/CF nanostructure is expected to be a type of excellent electrode material for electrical double layer capacitors.

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.

Dip-Coating Process Engineering and Performance Optimization for Three-State Electrochromic Devices

NASA Astrophysics Data System (ADS)

Wu, Lu; Yang, Dejiang; Fei, Lixun; Huang, Yue; Wu, Fang; Sun, Yiling; Shi, Jiayuan; Xiang, Yong

2017-06-01

Titanium dioxide (TiO2) nanoparticles were modified onto fluorine-doped tin oxide (FTO) via dip-coating technique with different nanoparticle sizes, lifting speeds, precursor concentrations, and dipping numbers. Electrodeposition-based electrochromic device with reversible three-state optical transformation (transparent, mirror, and black) was fabricated subsequently by sandwiching a suitable amount of gel electrolyte between modified FTO electrode and flat FTO electrode. Correlation between dip-coating process engineering, morphological features of TiO2 thin films, i.e., thickness and roughness, as well as performance of electrochromic devices, i.e., optical contrast, switching time, and cycling stability, were investigated. The modified device exhibits high optical contrast of 57%, the short coloration/bleaching switching time of 6 and 20 s, and excellent cycling stability after 1500 cycles of only 27% decrement rate by adjusting dip-coating processes engineering. The results in this study will provide valuable guidance for rational design of the electrochromic device with satisfactory performance.

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.

High-performance cobalt carbonate hydroxide nano-dot/NiCo(CO3)(OH)2 electrode for asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Lee, Damin; Xia, Qi Xun; Yun, Je Moon; Kim, Kwang Ho

2018-03-01

Binder-free mesoporous NiCo(CO3)(OH)2 nanowire arrays were grown using a facile hydrothermal technique. The Co2(CO3)(OH)2 in NiCo(CO3)(OH)2 nanowire arrays was well-decorated as nano-dot scale (a few nanometer). In addition, increasing cobalt content in nickel compound matrix, NiCo(CO3)(OH)2 nanowire arrays were separately uniformly grown without agglomeration on Ni foam, providing a high specific surface area to help electrolyte access and ion transfer. The enticing composition and morphology of the NiCo(CO3)(OH)2 nanowire exhibit a superior specific capacity of 1288.2 mAh g-1 at a current density of 3 A g-1 and excellent cycling stability with the capacity retention of 80.7% after 10,000 cycles. Furthermore, an asymmetric supercapacitor composed of the NiCo(CO3)(OH)2 composite as a positive electrode and the graphene as a negative electrode presented a high energy density of 35.5 W h kg-1 at a power density of 2555.6 W kg-1 and satisfactory cycling stability with 71.3% capacity retention after 10,000 cycles. The great combination of the active nano-dot Co2(CO3)(OH)2 and the individually grown NiCo(CO3)(OH)2 nanowires made it a promising electrode material for asymmetric supercapacitors. A well-developed nanoarchitecture of the nano-dot Co2(CO3)(OH)2 decorated NiCo(CO3)(OH)2 composite could pave the way for an excellent electrode design for high-performance supercapacitors.

Assembly of flexible CoMoO4@NiMoO4·xH2O and Fe2O3 electrodes for solid-state asymmetric supercapacitors

PubMed Central

Wang, Jing; Zhang, Leipeng; Liu, Xusong; Zhang, Xiang; Tian, Yanlong; Liu, Xiaoxu; Zhao, Jiupeng; Li, Yao

2017-01-01

In this work, CoMoO4@NiMoO4·xH2O core-shell heterostructure electrode is directly grown on carbon fabric (CF) via a feasible hydrothermal procedure with CoMoO4 nanowires (NWs) as the core and NiMoO4 nanosheets (NSs) as the shell. This core-shell heterostructure could provide fast ion and electron transfer, a large number of active sites, and good strain accommodation. As a result, the CoMoO4@NiMoO4·xH2O electrode yields high-capacitance performance with a high specific capacitance of 1582 F g−1, good cycling stability with the capacitance retention of 97.1% after 3000 cycles and good rate capability. The electrode also shows excellent mechanical flexibility. Also, a flexible Fe2O3 nanorods/CF electrode with enhanced electrochemical performance was prepared. A solid-state asymmetric supercapacitor device is successfully fabricated by using flexible CoMoO4@NiMoO4·xH2O as the positive electrode and Fe2O3 as the negative electrode. The asymmetric supercapacitor with a maximum voltage of 1.6 V demonstrates high specific energy (41.8 Wh kg−1 at 700 W kg−1), high power density (12000 W kg−1 at 26.7 Wh kg−1), and excellent cycle ability with the capacitance retention of 89.3% after 5000 cycles (at the current density of 3A g−1). PMID:28106170

Facile synthesis of birnessite-type manganese oxide nanoparticles as supercapacitor electrode materials.

PubMed

Liu, Lihu; Luo, Yao; Tan, Wenfeng; Zhang, Yashan; Liu, Fan; Qiu, Guohong

2016-11-15

Manganese oxides are environmentally benign supercapacitor electrode materials and, in particular, birnessite-type structure shows very promising electrochemical performance. In this work, nanostructured birnessite was facilely prepared by adding dropwise NH2OH·HCl to KMnO4 solution under ambient temperature and pressure. In order to fully exploit the potential of birnessite-type manganese oxide electrode materials, the effects of specific surface area, pore size, content of K(+), and manganese average oxidation state (Mn AOS) on their electrochemical performance were studied. The results showed that with the increase of NH2OH·HCl, the Mn AOS decreased and the corresponding pore sizes and specific surface area of birnessite increased. The synthesized nanostructured birnessite showed the highest specific capacitance of 245Fg(-1) at a current density of 0.1Ag(-1) within a potential range of 0-0.9V, and excellent cycle stability with a capacitance retention rate of 92% after 3000 cycles at a current density of 1.0Ag(-1). The present work implies that specific capacitance is mainly affected by specific surface area and pore volume, and provides a new method for the facile preparation of birnessite-type manganese oxide with excellent capacitive performance. Copyright © 2016 Elsevier Inc. All rights reserved.

Enhanced supercapacitance of activated vertical graphene nanosheets in hybrid electrolyte

NASA Astrophysics Data System (ADS)

Ghosh, Subrata; Sahoo, Gopinath; Polaki, S. R.; Krishna, Nanda Gopala; Kamruddin, M.; Mathews, Tom

2017-12-01

Supercapacitors are becoming the workhorse for emerging energy storage applications due to their higher power density and superior cycle life compared to conventional batteries. The performance of supercapacitors depends on the electrode material, type of electrolyte, and interaction between them. Owing to the beneficial interconnected porous structure with multiple conducting channels, vertical graphene nanosheets (VGN) have proved to be leading supercapacitor electrode materials. Herein, we demonstrate a novel approach based on the combination of surface activation and a new organo-aqueous hybrid electrolyte, tetraethylammonium tetrafluoroborate in H2SO4, to achieve significant enhancement in supercapacitor performance of VGN. As-synthesized VGN exhibits an excellent supercapacitance of 0.64 mF/cm2 in H2SO4. However, identification of a novel electrolyte for performance enhancement is the subject of current research. The present manuscript demonstrates the potential of the hybrid electrolyte in enhancing the areal capacitance (1.99 mF/cm2) with excellent retention (only 5.4% loss after 5000 cycles) and Coulombic efficiency (93.1%). In addition, a five-fold enhancement in the capacitance of VGNs (0.64 to 3.31 mF/cm2) with a reduced internal resistance is achieved by the combination of KOH activation and the hybrid electrolyte.

Skeleton/skin structured (RGO/CNTs)@PANI composite fiber electrodes with excellent mechanical and electrochemical performance for all-solid-state symmetric supercapacitors.

PubMed

Liu, Dong; Du, Pengcheng; Wei, Wenli; Wang, Hongxing; Wang, Qi; Liu, Peng

2018-03-01

Polyaniline coated reduced graphene oxide/carbon nanotube composite fibers ((RGO/CNTs)@PANI, RCP) with skeleton/skin structure are designed as fiber-shaped electrodes for high performance all-solid-state symmetric supercapacitor. The one-dimensional reduced graphene oxide/carbon nanotube composite fibers (RGO/CNTs, RC) are prepared via a simple in-situ reduction of graphene oxide in presence of carbon nanotubes in quartz glass pipes, which exhibit excellent mechanical performance of >193.4 MPa of tensile strength. Then polyaniline is coated onto the RC fibers by electrodepositing technique. The electrochemical properties of the RCP fiber-shaped electrodes are optimized by adjusting the feeding ratio of carbon nanotubes. The optimized one exhibits good electrochemical characteristic such as highest volumetric specific capacitance of 193.1 F cm -3 at 1 A cm -3 , as well as excellent cyclic retention of 92.60% after 2000 cyclic voltammetry cycles. Furthermore, the all-solid-state symmetric supercapacitor, fabricated by using the final composite fiber as both positive and negative electrodes pre-coated with the poly(vinyl alcohol)/H 2 SO 4 gel polyelectrolyte, possesses volumetric capacitance of 36.7 F cm -3 at 0.2 A cm -3 and could light up a red light-emitting diode easily. The excellent mechanical and electrochemical performances make the designed supercapacitor as promising high performance wearable energy storage device. Copyright © 2017 Elsevier Inc. All rights reserved.

Hierarchical core-shell NiCo2O4@NiMoO4 nanowires grown on carbon cloth as integrated electrode for high-performance supercapacitors

PubMed Central

Huang, Liang; Zhang, Wei; Xiang, Jinwei; Xu, Henghui; Li, Guolong; Huang, Yunhui

2016-01-01

Hierarchical core-shell NiCo2O4@NiMoO4 nanowires were grown on carbon cloth (CC@NiCo2O4@NiMoO4) by a two-step hydrothermal route to fabricate a flexible binder-free electrode. The prepared CC@NiCo2O4@NiMoO4 integrated electrode was directly used as an electrode for faradaic supercapacitor. It shows a high areal capacitance of 2.917 F cm−2 at 2 mA cm−2 and excellent cycling stability with 90.6% retention over 2000 cycles at a high current density of 20 mA cm−2. The superior specific capacitance, rate and cycling performance can be ascribed to the fast transferring path for electrons and ions, synergic effect and the stability of the hierarchical core-shell structure. PMID:27515274

Asymmetric supercapacitors with high energy density based on helical hierarchical porous Na x MnO2 and MoO2.

PubMed

Lu, Xue-Feng; Huang, Zhi-Xiang; Tong, Ye-Xiang; Li, Gao-Ren

2016-01-01

Helical hierarchical porous Na x MnO 2 /CC and MoO 2 /CC, which are assembled from nanosheets and nanoparticles, respectively, are fabricated using a simple electrodeposition method. These unique helical porous structures enable electrodes to have a high capacitance and an outstanding cycling performance. Based on the helical Na x MnO 2 /CC as the positive electrodes and helical MoO 2 /CC as the negative electrodes, high performance Na x MnO 2 /CC//MoO 2 /CC asymmetric supercapacitors (ASCs) are successfully assembled, and they achieve a maximum volume C sp of 2.04 F cm -3 and a maximum energy density of 0.92 mW h cm -3 for the whole device and an excellent cycling stability with 97.22% C sp retention after 6000 cycles.

Hierarchical core-shell NiCo2O4@NiMoO4 nanowires grown on carbon cloth as integrated electrode for high-performance supercapacitors.

PubMed

Huang, Liang; Zhang, Wei; Xiang, Jinwei; Xu, Henghui; Li, Guolong; Huang, Yunhui

2016-08-12

Hierarchical core-shell NiCo2O4@NiMoO4 nanowires were grown on carbon cloth (CC@NiCo2O4@NiMoO4) by a two-step hydrothermal route to fabricate a flexible binder-free electrode. The prepared CC@NiCo2O4@NiMoO4 integrated electrode was directly used as an electrode for faradaic supercapacitor. It shows a high areal capacitance of 2.917 F cm(-2) at 2 mA cm(-2) and excellent cycling stability with 90.6% retention over 2000 cycles at a high current density of 20 mA cm(-2). The superior specific capacitance, rate and cycling performance can be ascribed to the fast transferring path for electrons and ions, synergic effect and the stability of the hierarchical core-shell structure.

Hierarchical core-shell NiCo2O4@NiMoO4 nanowires grown on carbon cloth as integrated electrode for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Huang, Liang; Zhang, Wei; Xiang, Jinwei; Xu, Henghui; Li, Guolong; Huang, Yunhui

2016-08-01

Hierarchical core-shell NiCo2O4@NiMoO4 nanowires were grown on carbon cloth (CC@NiCo2O4@NiMoO4) by a two-step hydrothermal route to fabricate a flexible binder-free electrode. The prepared CC@NiCo2O4@NiMoO4 integrated electrode was directly used as an electrode for faradaic supercapacitor. It shows a high areal capacitance of 2.917 F cm-2 at 2 mA cm-2 and excellent cycling stability with 90.6% retention over 2000 cycles at a high current density of 20 mA cm-2. The superior specific capacitance, rate and cycling performance can be ascribed to the fast transferring path for electrons and ions, synergic effect and the stability of the hierarchical core-shell structure.

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.

Highly deformation-tolerant carbon nanotube sponges as supercapacitor electrodes.

PubMed

Li, Peixu; Kong, Chuiyan; Shang, Yuanyuan; Shi, Enzheng; Yu, Yuntao; Qian, Weizhong; Wei, Fei; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Cao, Anyuan; Wu, Dehai

2013-09-21

Developing flexible and deformable supercapacitor electrodes based on porous materials is of high interest in energy related fields. Here, we show that carbon nanotube sponges, consisting of highly porous conductive networks, can serve as compressible and deformation-tolerant supercapacitor electrodes in aqueous or organic electrolytes. In aqueous electrolytes, the sponges maintain a similar specific capacitance (>90% of the original value) under a predefined compressive strain of 50% (corresponding to a volume reduction of 50%), and retain more than 70% of the original capacitance under 80% strain while the volume normalized capacitance increases by 3-fold. The sponge electrode maintains a stable performance after 1000 large strain compression cycles. A coin-shaped cell assembled with these sponges shows excellent stability over 15,000 charging cycles with negligible degradation after 500 cycles. Our results indicate that carbon nanotube sponges have the potential to fabricate deformable supercapacitor electrodes with stable performance.

Mesoporous Li1.2Mn0.54Ni0.13Co0.13O2 nanotubes for high-performance cathodes in Li-ion batteries

NASA Astrophysics Data System (ADS)

Ma, Dingtao; Li, Yongliang; Zhang, Peixin; Cooper, Adam J.; Abdelkader, Amr M.; Ren, Xiangzhong; Deng, Libo

2016-04-01

One-dimensional nanotubes constructed from interconnected Li1.2Mn0.54Ni0.13Co0.13O2 secondary particles of diameters measuring ca. 40 nm, were synthesized by a one-pot electrospinning method. Novel electrodes were constructed from (a) nanoparticles only, and (b) hollow nanofibres, and employed as cathodes in Li-ion batteries. The nanotube cathode exhibited impressive specific charge capacity, good cycling stability, and excellent rate capability. A discharge capacity of 140 mAh g-1 with capacity retention of 89% at 3 C was achieved after 300 cycles. The significant improvement of electrochemical performance is attributed to the high surface area of the nanotubes, well-guided charge transfer kinetics with short ionic diffusion pathways, and large effective contact area with the electrolyte during the cycling process.

Durability of foam insulation for LH2 fuel tanks of future subsonic transports

NASA Technical Reports Server (NTRS)

Sharpe, E. L.; Helenbrook, R. G.

1978-01-01

In connection with the potential short-supply of petroleum based fuels, NASA has initiated investigations concerning the feasibility of aircraft using as fuel hydrogen which is to be stored in liquid form. One of the problems to be solved for an operation of such aircraft is related to the possibility of a suitable storage of the liquid hydrogen. A description is presented of an experimental study regarding the suitability of commercially available organic foams as cryogenic insulation for liquid hydrogen tanks under extensive thermal cycling typical of subsonic airline type operation. Fourteen commercially available organic foam insulations were tested. The thermal performance of all insulations was found to deteriorate with increased simulated flight cycles. Two unreinforced polyurethane foams survived over 4200 thermal cycles (representative of approximately 15 years of airline service) without evidence of structural deterioration. The polyurethane foam insulations also exhibited excellent thermal performance.

Scalable Synthesis of Defect Abundant Si Nanorods for High-Performance Li-Ion Battery Anodes.

PubMed

Wang, Jing; Meng, Xiangcai; Fan, Xiulin; Zhang, Wenbo; Zhang, Hongyong; Wang, Chunsheng

2015-06-23

Microsized nanostructured silicon-carbon composite is a promising anode material for high energy Li-ion batteries. However, large-scale synthesis of high-performance nano-Si materials at a low cost still remains a significant challenge. We report a scalable low cost method to synthesize Al/Na-doped and defect-abundant Si nanorods that have excellent electrochemical performance with high first-cycle Coulombic efficiency (90%). The unique Si nanorods are synthesized by acid etching the refined and rapidly solidified eutectic Al-Si ingot. To maintain the high electronic conductivity, a thin layer of carbon is then coated on the Si nanorods by carbonization of self-polymerized polydopamine (PDA) at 800 °C. The carbon coated Si nanorods (Si@C) electrode at 0.9 mg cm(-2) loading (corresponding to area-specific-capacity of ∼2.0 mAh cm(-2)) exhibits a reversible capacity of ∼2200 mAh g(-1) at 100 mA g(-1) current, and maintains ∼700 mAh g(-1) over 1000 cycles at 1000 mA g(-1) with a capacity decay rate of 0.02% per cycle. High Coulombic efficiencies of 87% in the first cycle and ∼99.7% after 5 cycles are achieved due to the formation of an artificial Al2O3 solid electrolyte interphase (SEI) on the Si surface, and the low surface area (31 m(2) g(-1)), which has never been reported before for nano-Si anodes. The excellent electrochemical performance results from the massive defects (twins, stacking faults, dislocations) and Al/Na doping in Si nanorods induced by rapid solidification and Na salt modifications; this greatly enhances the robustness of Si from the volume changes and alleviates the mechanical stress/strain of the Si nanorods during the lithium insertion/extraction process. Introducing massive defects and Al/Na doping in eutectic Si nanorods for Li-ion battery anodes is unexplored territory. We venture this uncharted territory to commercialize this nanostructured Si anode for the next generation of Li-ion batteries.

Encapsulation of α-Fe2O3 nanoparticles in graphitic carbon microspheres as high-performance anode materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Zhang, Hongwei; Sun, Xiaoran; Huang, Xiaodan; Zhou, Liang

2015-02-01

A novel ``spray drying-carbonization-oxidation'' strategy has been developed for the fabrication of α-Fe2O3-graphitic carbon (α-Fe2O3@GC) composite microspheres, in which α-Fe2O3 nanoparticles with sizes of 30-50 nm are well-encapsulated by onion-like graphitic carbon shells with a thickness of 5-10 nm. In the constructed composite, the α-Fe2O3 nanoparticles act as the primary active material, providing a high capacity. Meanwhile, the graphitic carbon shells serve as the secondary active component, structural stabilizer, interfacial stabilizer, and electron-highway. As a result, the synthesized α-Fe2O3@GC nanocomposite exhibits a superior lithium-ion battery performance with a high reversible capacity (898 mA h g-1 at 400 mA g-1), outstanding rate capability, and excellent cycling stability. Our product, in terms of the facile and scalable preparation process and excellent electrochemical performance, demonstrates its great potential as a high-performance anode material for lithium-ion batteries.A novel ``spray drying-carbonization-oxidation'' strategy has been developed for the fabrication of α-Fe2O3-graphitic carbon (α-Fe2O3@GC) composite microspheres, in which α-Fe2O3 nanoparticles with sizes of 30-50 nm are well-encapsulated by onion-like graphitic carbon shells with a thickness of 5-10 nm. In the constructed composite, the α-Fe2O3 nanoparticles act as the primary active material, providing a high capacity. Meanwhile, the graphitic carbon shells serve as the secondary active component, structural stabilizer, interfacial stabilizer, and electron-highway. As a result, the synthesized α-Fe2O3@GC nanocomposite exhibits a superior lithium-ion battery performance with a high reversible capacity (898 mA h g-1 at 400 mA g-1), outstanding rate capability, and excellent cycling stability. Our product, in terms of the facile and scalable preparation process and excellent electrochemical performance, demonstrates its great potential as a high-performance anode material for lithium-ion batteries. Electronic supplementary information (ESI) available: XRD pattern, XPS spectrum, CV curves, TEM and SEM images, and table. See DOI: 10.1039/c4nr06771a

Niobium Application, Metallurgy and Global Trends in Pressure Vessel Steels

NASA Astrophysics Data System (ADS)

Jansto, Steven G.

Niobium-containing high strength steel materials have been developed for a variety of pressure vessel applications. Through the application of these Nb-bearing steels in demanding applications, the designer and end user experience improved toughness at low temperature, excellent fatigue resistance and fracture toughness and excellent weldability. These enhancements provide structural engineers the opportunity to further improve the pressure vessel design and performance. The Nb-microalloy alloy designs also result in reduced operational production cost at the steel operation, thereby embracing the value-added attribute Nb provides to both the producer and the end user throughout the supply chain. For example, through the adoption of these Nb-containing structural materials, several design-manufacturing companies are considering improved designs which offer improved manufacturability, lower overall cost and better life cycle performance.

Room temperature solvent-free reduction of SiCl4 to nano-Si for high-performance Li-ion batteries.

PubMed

Liu, Zhiliang; Chang, Xinghua; Sun, Bingxue; Yang, Sungjin; Zheng, Jie; Li, Xingguo

2017-06-06

SiCl 4 can be directly reduced to nano-Si with commercial Na metal under solvent-free conditions by mechanical milling. Crystalline nano-Si with an average size of 25 nm and quite uniform size distribution can be obtained, which shows excellent lithium storage performance, for a high reversible capacity of 1600 mA h g -1 after 500 cycles at 2.1 A g -1 .

A facile approach to fabricate flexible all-solid-state supercapacitors based on MnFe2O4/graphene hybrids

NASA Astrophysics Data System (ADS)

Cai, Weihua; Lai, Ting; Dai, Wanlin; Ye, Jianshan

2014-06-01

A critical challenge for the construction of flexible electrochemical capacitors is the preparation of flexible electrodes with large specific capacitance and robust mechanical strength. Here, we demonstrate a facile approach to make high performance and flexible electrodes by dropping MnFe2O4/graphene hybrid inks onto flexible graphite sheets (as current collectors and substrates) and drying under an infrared lamp. MnFe2O4/graphene hybrid inks are synthesized by immobilizing the MnFe2O4 microspheres on the graphene nanosheets via a simple solvothermal route. Electrochemical studies show that MnFe2O4/graphene exhibits a high capacitance of 300 F g-1 at a current density of 0.3 A g-1. In addition, the excellent electrochemical performance of a supercapacitor consisting of a sandwich structure of two pieces of MnFe2O4/graphene hybrids modified electrodes separated by polyvinyl alcohol (PVA)-H2SO4 gel electrolyte is further explored. Our studies reveal that the flexible supercapacitor device with 227 μm thickness can achieve a maximum specific capacitance of 120 F g-1 at a current density of 0.1 A g-1 and excellent cycle performance retaining 105% capacitance after 5000 cycles. This research may offer a method for the fabrication of lightweight, stable, flexible and high performance energy storage devices.

The critical role of sodium content on structure, morphology and electrochemical performance of layered P2-type NaxNi0.167Co0.167Mn0.67O2 for sodium ion batteries

NASA Astrophysics Data System (ADS)

Bao, Shuo; Luo, Shaohua; Wang, Zhiyuan; Wang, Qing; Hao, Aimin; Zhang, Yahui; Wang, Yingling

2017-09-01

P2-type manganese-based ternary transition metal oxides have triggered extensive researches as potential cathode materials for sodium ion batteries. However, these kinds of materials display the large difference in electrochemical performance with sodium content varying from 0.45 to 0.8, the relevant investigations on effects of sodium content are insufficient. In this work, we synthesize a series of spherical P2-type cathode materials NaxNi0.167Co0.167Mn0.67O2 with different sodium content (x = 0.45, 0.55, 0.67, 0.8, 0.9, 1) and investigate the effects of sodium content on structure and electrochemical performance. The results reveal that NaxNi0.167Co0.167Mn0.67O2 (x = 0.45, 0.55) consist of P2-phase and P3-phase, while NaxNi0.167Co0.167Mn0.67O2 (x = 0.67, 0.8, 0.9, 1) exhibit pure P2-phase. Na0.45Ni0.167Co0.167Mn0.67O2 delivers an initial discharge capacity of 143 mAh g-1, while a fast capacity decay is observed after 50 cycles. In comparison, Na0.67Ni0.167Co0.167Mn0.67O2 shows excellent cycling stability and rate performance. The significant difference in electrochemical performance is attributed to the initial sodium content, which leads to the existence of P3-phase. Moreover, higher sodium content promotes primary particles to grow larger and thicker, which is not favorable for the diffusion of Na+. Generally, Na0.67Ni0.167Co0.167Mn0.67O2 is favored by suitable sodium content, offers excellent electrochemical performance in terms of capacity, rate performance and cycling stability.

MoO2-ordered mesoporous carbon hybrids as anode materials with highly improved rate capability and reversible capacity for lithium-ion battery.

PubMed

Chen, Ailian; Li, Caixia; Tang, Rui; Yin, Longwei; Qi, Yongxin

2013-08-28

A novel hybrid of MoO2-ordered mesoporous carbon (MoO2-OMC) was prepared through a two-step solvothermal chemical reaction route. The electrochemical performances of the mesoporous MoO2-OMC hybrids were examined using galvanostatical charge-discharge, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS) techniques. The MoO2-OMC hybrid exhibits significantly improved electrochemical performance of high reversible capacity, high-rate capability, and excellent cycling performance as an anode electrode material for Li ion batteries. It is revealed that the MoO2-OMC hybrid could deliver the first discharge capacity of 1641.8 mA h g(-1) with an initial Coulombic efficiency of 63.6%, and a reversible capacity as high as 1049.1 mA h g(-1) even after 50 cycles at a current density of 100 mA g(-1), much higher than the theoretical capacity of MoO2 (838 mA h g(-1)) and OMC materials. The MoO2-OMC hybrid demonstrates an excellent high rate capability with capacity of ∼600 mA h g(-1) even at a charge current density of 1600 mA g(-1) after 50 cycles, which is approximately 11.1 times higher than that of the OMC (54 mA h g(-1)) materials. The improved rate capability and reversible capacity of the MoO2-OMC hybrid are attributed to a synergistic reaction between the MoO2 nanoparticles and mesoporous OMC matrices. It is noted that the electrochemical performance of the MoO2-OMC hybrid is evidently much better than the previous MoO2-based hybrids.

High rate and stable cycling of lithium metal anode

PubMed Central

Qian, Jiangfeng; Henderson, Wesley A.; Xu, Wu; Bhattacharya, Priyanka; Engelhard, Mark; Borodin, Oleg; Zhang, Ji-Guang

2015-01-01

Lithium metal is an ideal battery anode. However, dendrite growth and limited Coulombic efficiency during cycling have prevented its practical application in rechargeable batteries. Herein, we report that the use of highly concentrated electrolytes composed of ether solvents and the lithium bis(fluorosulfonyl)imide salt enables the high-rate cycling of a lithium metal anode at high Coulombic efficiency (up to 99.1%) without dendrite growth. With 4 M lithium bis(fluorosulfonyl)imide in 1,2-dimethoxyethane as the electrolyte, a lithium|lithium cell can be cycled at 10 mA cm−2 for more than 6,000 cycles, and a copper|lithium cell can be cycled at 4 mA cm−2 for more than 1,000 cycles with an average Coulombic efficiency of 98.4%. These excellent performances can be attributed to the increased solvent coordination and increased availability of lithium ion concentration in the electrolyte. Further development of this electrolyte may enable practical applications for lithium metal anode in rechargeable batteries. PMID:25698340

Flexible Nb2O5 nanowires/graphene film electrode for high-performance hybrid Li-ion supercapacitors

NASA Astrophysics Data System (ADS)

Song, Hao; Fu, Jijiang; Ding, Kang; Huang, Chao; Wu, Kai; Zhang, Xuming; Gao, Biao; Huo, Kaifu; Peng, Xiang; Chu, Paul K.

2016-10-01

The hybrid Li-ion electrochemical supercapacitor (Li-HSC) combining the battery-like anode with capacitive cathode is a promising energy storage device boasting large energy and power densities. Orthorhombic Nb2O5 is a good anode material in Li-HSCs because of its large pseudocapacitive Li-ion intercalation capacity. Herein, we report a high-performance, binder-free and flexible anode consisting of long Nb2O5 nanowires and graphene (L-Nb2O5 NWs/rGO). The paper-like L-Nb2O5 NWs/rGO film electrode has a large mass loading of Nb2O5 of 93.5 wt% as well as short solid-state ion diffusion length, and enhanced conductivity (5.1 S cm-1). The hybrid L-Nb2O5 NWs/rGO paper electrode shows a high reversible specific capacity of 160 mA h g-1 at a current density of 0.2 A g-1, superior rate capability with capacitance retention of 60% when the current density increases from 0.2 to 5 A g-1, as well as excellent cycle stability. The Li-HSC device based on the L-Nb2O5/rGO anode and the cathode of biomass-derived carbon nanosheets delivers an energy density of 106 Wh kg-1 at 580 W kg-1 and 32 Wh kg-1 at a large power density of 14 kW kg-1. Moreover, the Li-HSC device exhibits excellent cycling performance without obvious capacitance decay after 1000 cycles.

Ni nanoparticles@Ni-Mo nitride nanorod arrays: a novel 3D-network hierarchical structure for high areal capacitance hybrid supercapacitors.

PubMed

Ruan, Yunjun; Lv, Lin; Li, Zhishan; Wang, Chundong; Jiang, Jianjun

2017-11-23

Because of the advanced nature of their high power density, fast charge/discharge time, excellent cycling stability, and safety, supercapacitors have attracted intensive attention for large-scale applications. Nevertheless, one of the obstacles for their further development is their low energy density caused by sluggish redox reaction kinetics, low electroactive electrode materials, and/or high internal resistance. Here, we develop a facile and simple nitridation process to successfully synthesize hierarchical Ni nanoparticle decorated Ni 0.2 Mo 0.8 N nanorod arrays on a nickel foam (Ni-Mo-N NRA/NF) from its NiMoO 4 precursor, which delivers a high areal capacity of 2446 mC cm -2 at a current density of 2 mA cm -2 and shows outstanding cycling stability. The superior performance of the Ni-Mo-N NRA/NF can be ascribed to the metallic conductive nature of the Ni-Mo nitride, the fast surface redox reactions for the electrolyte ions and electrode materials, and the low contacted resistance between the active materials and the current collectors. Furthermore, a hybrid supercapacitor (HSC) is assembled using the Ni-Mo-N NRA/NF as the positive electrode and reduced graphene oxide (RGO) as the negative electrode. The optimized HSC exhibits excellent electrochemical performance with a high energy density of 40.9 W h kg -1 at a power density of 773 W kg -1 and a retention of 80.1% specific capacitance after 6000 cycles. These results indicate that the Ni-Mo-N NRA/NF have a promising potential for use in high-performance supercapacitors.

Free-standing porous manganese dioxide/graphene composite films for high performance supercapacitors.

PubMed

Guo, Wang-Huan; Liu, Teng-Jiao; Jiang, Peng; Zhang, Zhan-Jun

2015-01-01

A simple hard template method and hydrothermal process have been employed to fabricate a self-standing hierarchical porous MnO2/graphene film. Thus-constructed electrode materials for binder-free supercapacitors exhibit a high specific capacitance of 266.3 F g(-1) at the density of 0.2 A g(-1). Moreover, the two-electrode device demonstrates an excellent rate capability and cycling stability with capacitance retention of 85.1% after 2000 charge-discharge cycles at a current density of 1 A g(-1). The porous nanostructured design can effectively improve the specific surface areas and account for the shorter relaxation time for the electrodes, resulting in a high electrochemical performance. Copyright © 2014 Elsevier Inc. All rights reserved.

Facile synthesis of a SiOx/asphalt membrane for high performance lithium-ion battery anodes.

PubMed

Xu, Quan; Sun, Jian-Kun; Li, Ge; Li, Jin-Yi; Yin, Ya-Xia; Guo, Yu-Guo

2017-11-07

Herein, a novel SiO x /asphalt membrane was facilely synthesized via demulsification of porous SiO x microspheres. After high temperature pyrolysis, SiO x /carbon composites not only could function as binder-free anodes, but could also exhibit excellent cycling stability and high initial Coulombic efficiency as anodes for practical application.

Hypersonic Technology Developments with EU Co-Funded Projects

DTIC Science & Technology

2010-09-01

metal or even high performance alloys . The hollow sphere technology allows high degrees of porosities, reproducible properties and fair process control...sandwich structure configuration will be investigated. Titanium alloys and Ti-aluminides exhibit excellent mechanical properties for applications where...cooling techniques, new alloys , improved thermodynamic cycles by increased pressure ratios and TIT, etc… As the Olympus 593 engine was based on the

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.

An Ideal Electrode Material, 3D Surface-Microporous Graphene for Supercapacitors with Ultrahigh Areal Capacitance

DOE PAGES

Chang, Liang; Stacchiola, Dario J.; Hu, Yun Hang

2017-07-03

The efficient charge accumulation of an ideal supercapacitor electrode requires abundant micropores and its fast electrolyte-ions transport prefers meso/macropores. But, current electrode materials cannot meet both requirements, resulting in poor performance. We creatively constructed three-dimensional cabbage-coral-like graphene as an ideal electrode material, in which meso/macro channels are formed by graphene walls and rich micropores are incorporated in the surface layer of the graphene walls. The unique 3D graphene material can achieve a high gravimetric capacitance of 200 F/g with aqueous electrolyte, 3 times larger than that of commercially used activated carbon (70.8 F/g). Furthermore, it can reach an ultrahigh arealmore » capacitance of 1.28 F/cm 2 and excellent rate capability (83.5% from 0.5 to 10 A/g) as well as high cycling stability (86.2% retention after 5000 cycles). The excellent electric double-layer performance of the 3D graphene electrode can be attributed to the fast electrolyte ion transport in the meso/macro channels and the rapid and reversible charge adsorption with negligible transport distance in the surface micropores.« less

An Ideal Electrode Material, 3D Surface-Microporous Graphene for Supercapacitors with Ultrahigh Areal Capacitance

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

Chang, Liang; Stacchiola, Dario J.; Hu, Yun Hang

The efficient charge accumulation of an ideal supercapacitor electrode requires abundant micropores and its fast electrolyte-ions transport prefers meso/macropores. But, current electrode materials cannot meet both requirements, resulting in poor performance. We creatively constructed three-dimensional cabbage-coral-like graphene as an ideal electrode material, in which meso/macro channels are formed by graphene walls and rich micropores are incorporated in the surface layer of the graphene walls. The unique 3D graphene material can achieve a high gravimetric capacitance of 200 F/g with aqueous electrolyte, 3 times larger than that of commercially used activated carbon (70.8 F/g). Furthermore, it can reach an ultrahigh arealmore » capacitance of 1.28 F/cm 2 and excellent rate capability (83.5% from 0.5 to 10 A/g) as well as high cycling stability (86.2% retention after 5000 cycles). The excellent electric double-layer performance of the 3D graphene electrode can be attributed to the fast electrolyte ion transport in the meso/macro channels and the rapid and reversible charge adsorption with negligible transport distance in the surface micropores.« less

Probing the characteristics of casein as green binder for non-aqueous electrochemical double layer capacitors' electrodes

NASA Astrophysics Data System (ADS)

Varzi, Alberto; Raccichini, Rinaldo; Marinaro, Mario; Wohlfahrt-Mehrens, Margret; Passerini, Stefano

2016-09-01

Casein from bovine milk is evaluated in this work as binding agent for electrochemical double layer capacitors (EDLCs) electrodes. It is demonstrated that casein provides excellent adhesion strength to the current collector (1187 kPa compared to 51 kPa achieved with PVdF), thus leading to mechanically stable electrodes. At the same time, it offers high thermal stability (above 200 °C) and electrochemical stability in organic electrolytes. Apparently though, the casein-based electrodes offer lower electronic conductivity than those based on other state-of-the-art binders, which can limit the rate performance of the resulting EDLC. In the attempt of improving the electrochemical performance, it is found that the application of a pressing step can solve this issue, leading to excellent rate capability (up to 84% capacitance retention at 50 mA cm-2) and cycling stability (96.8% after 10,000 cycles at 10 mA cm-2) in both PC- and ACN-based electrolytes. Although the adhesive power casein is known since ancient times, this report presents the first proof of concept of its employment in electrochemical power sources.

A honeycomb-like porous carbon derived from pomelo peel for use in high-performance supercapacitors

NASA Astrophysics Data System (ADS)

LiangThese Two Authors Are Equal Main Contributors., Qinghua; Ye, Ling; Huang, Zheng-Hong; Xu, Qiang; Bai, Yu; Kang, Feiyu; Yang, Quan-Hong

2014-10-01

A cost-effective approach to obtain electrode materials with excellent electrochemical performance is critical to the development of supercapacitors (SCs). Here we report the preparation of a three-dimensional (3D) honeycomb-like porous carbon (HLPC) by the simple carbonization of pomelo peel followed by KOH activation. Structural characterization indicates that the as-prepared HLPC with a high specific surface area (SSA) up to 2725 m2 g-1 is made up of interconnected microporous carbon walls. Chemical analysis shows that the HLPC is doped with nitrogen and also has oxygen-containing groups. Electrochemical measurements show that the HLPC not only exhibits a high specific capacitance of 342 F g-1 and 171 F cm-3 at 0.2 A g-1 but also shows considerable rate capability with a retention of 62% at 20 A g-1 as well as good cycling performance with 98% retention over 1000 cycles at 10 A g-1 in 6 M KOH. Furthermore, an as-fabricated HLPC-based symmetric SC device delivers a maximum energy density of ~9.4 Wh kg-1 in the KOH electrolyte. Moreover, the outstanding cycling stability (only 2% capacitance decay over 1000 cycles at 5 A g-1) of the SC device makes it promising for use in a high-performance electrochemical energy system.A cost-effective approach to obtain electrode materials with excellent electrochemical performance is critical to the development of supercapacitors (SCs). Here we report the preparation of a three-dimensional (3D) honeycomb-like porous carbon (HLPC) by the simple carbonization of pomelo peel followed by KOH activation. Structural characterization indicates that the as-prepared HLPC with a high specific surface area (SSA) up to 2725 m2 g-1 is made up of interconnected microporous carbon walls. Chemical analysis shows that the HLPC is doped with nitrogen and also has oxygen-containing groups. Electrochemical measurements show that the HLPC not only exhibits a high specific capacitance of 342 F g-1 and 171 F cm-3 at 0.2 A g-1 but also shows considerable rate capability with a retention of 62% at 20 A g-1 as well as good cycling performance with 98% retention over 1000 cycles at 10 A g-1 in 6 M KOH. Furthermore, an as-fabricated HLPC-based symmetric SC device delivers a maximum energy density of ~9.4 Wh kg-1 in the KOH electrolyte. Moreover, the outstanding cycling stability (only 2% capacitance decay over 1000 cycles at 5 A g-1) of the SC device makes it promising for use in a high-performance electrochemical energy system. Electronic supplementary information (ESI) available: Experimental section and additional table and figures (Fig. S1-S8). See DOI: 10.1039/c4nr04541f

High-cycle fatigue characterization of titanium 5Al-2.5Sn alloy

NASA Technical Reports Server (NTRS)

Mahfuz, H.; Xin, Yu T.; Jeelani, S.

1993-01-01

High-cycle fatigue behavior of titanium 5Al 2.5Sn alloy at room temperature has been studied. S-N curve characterization is performed at different stress ratios ranging from 0 to 0.9 on a subsized fatigue specimen. Both two-stress and three-stress level tests are conducted at different stress ratios to study the cumulative fatigue damage. Life prediction techniques of linear damage rule, double linear damage rule and damage curve approaches are applied, and results are compared with the experimental data. The agreement between prediction and experiment is found to be excellent.

Li+ /Mg2+ Hybrid-Ion Batteries with Long Cycle Life and High Rate Capability Employing MoS2 Nano Flowers as the Cathode Material.

PubMed

Ju, Yanming; Meng, Yuan; Wei, Yingjin; Bian, Xiaofei; Pang, Qiang; Gao, Yu; Du, Fei; Liu, Bingbing; Chen, Gang

2016-12-12

The demand for large-scale and safe energy storage is increasing rapidly due to the strong push for smartphones and electric vehicles. As a result, Li + /Mg 2+ hybrid-ion batteries (LMIBs) combining a dendrite-free deposition of Mg anode and Li + intercalation cathode have attracted considerable attention. Here, a LMIB with hydrothermal-prepared MoS 2 nano flowers as cathode material was prepared. The battery showed remarkable electrochemical properties with a large discharge capacity (243 mAh g -1 at the 0.1 C rate), excellent rate capability (108 mAh g -1 at the 5 C rate), and long cycle life (87.2 % capacity retention after 2300 cycles). Electrochemical analysis showed that the reactions occurring in the battery cell involved Mg stripping/plating at the anode side and Li + intercalation at the cathode side with a small contribution from Mg 2+ adsorption. The excellent electrochemical performance and extremely safe cell system show promise for its use in practical applications. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

High-performance graphene/sulphur electrodes for flexible Li-ion batteries using the low-temperature spraying method

NASA Astrophysics Data System (ADS)

Kumar, Pushpendra; Wu, Feng-Yu; Hu, Lung-Hao; Ali Abbas, Syed; Ming, Jun; Lin, Chia-Nan; Fang, Jason; Chu, Chih-Wei; Li, Lain-Jong

2015-04-01

Elementary sulphur (S) has been shown to be an excellent cathode material in energy storage devices such as Li-S batteries owing to its very high capacity. The major challenges associated with the sulphur cathodes are structural degradation, poor cycling performance and instability of the solid-electrolyte interphase caused by the dissolution of polysulfides during cycling. Tremendous efforts made by others have demonstrated that encapsulation of S materials improves their cycling performance. To make this approach practical for large scale applications, the use of low-cost technology and materials has become a crucial and new focus of S-based Li-ion batteries. Herein, we propose to use a low temperature spraying process to fabricate graphene/S electrode material, where the ink is composed of graphene flakes and the micron-sized S particles prepared by grinding of low-cost S powders. The S particles are found to be well hosted by highly conductive graphene flakes and consequently superior cyclability (~70% capacity retention after 250 cycles), good coulombic efficiency (~98%) and high capacity (~1500 mA h g-1) are obtained. The proposed approach does not require high temperature annealing or baking; hence, another great advantage is to make flexible Li-ion batteries. We have also demonstrated two types of flexible batteries using sprayed graphene/S electrodes.Elementary sulphur (S) has been shown to be an excellent cathode material in energy storage devices such as Li-S batteries owing to its very high capacity. The major challenges associated with the sulphur cathodes are structural degradation, poor cycling performance and instability of the solid-electrolyte interphase caused by the dissolution of polysulfides during cycling. Tremendous efforts made by others have demonstrated that encapsulation of S materials improves their cycling performance. To make this approach practical for large scale applications, the use of low-cost technology and materials has become a crucial and new focus of S-based Li-ion batteries. Herein, we propose to use a low temperature spraying process to fabricate graphene/S electrode material, where the ink is composed of graphene flakes and the micron-sized S particles prepared by grinding of low-cost S powders. The S particles are found to be well hosted by highly conductive graphene flakes and consequently superior cyclability (~70% capacity retention after 250 cycles), good coulombic efficiency (~98%) and high capacity (~1500 mA h g-1) are obtained. The proposed approach does not require high temperature annealing or baking; hence, another great advantage is to make flexible Li-ion batteries. We have also demonstrated two types of flexible batteries using sprayed graphene/S electrodes. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00885a

High-energy lithium-ion hybrid supercapacitors composed of hierarchical urchin-like WO3/C anodes and MOF-derived polyhedral hollow carbon cathodes.

PubMed

Xu, Juan; Li, Yuanyuan; Wang, Lei; Cai, Qifa; Li, Qingwei; Gao, Biao; Zhang, Xuming; Huo, Kaifu; Chu, Paul K

2016-09-22

A lithium-ion hybrid supercapacitor (Li-HSC) comprising a Li-ion battery type anode and an electrochemical double layer capacitance (EDLC) type cathode has attracted much interest because it accomplishes a large energy density without compromising the power density. In this work, hierarchical carbon coated WO 3 (WO 3 /C) with a unique mesoporous structure and metal-organic framework derived nitrogen-doped carbon hollow polyhedra (MOF-NC) are prepared and adopted as the anode and the cathode for Li-HSCs. The hierarchical mesoporous WO 3 /C microspheres assembled by radially oriented WO 3 /C nanorods along the (001) plane enable effective Li + insertion, thus exhibit high capacity, excellent rate performance and a long cycling life due to their high Li + conductivity, electronic conductivity and structural robustness. The WO 3 /C structure shows a reversible specific capacity of 508 mA h g -1 at a 0.1 C rate (1 C = 696 mA h g -1 ) after 160 discharging-charging cycles with excellent rate capability. The MOF-NC achieved the specific capacity of 269.9 F g -1 at a current density of 0.2 A g -1 . At a high current density of 6 A g -1 , 92.4% of the initial capacity could be retained after 2000 discharging-charging cycles, suggesting excellent cycle stability. The Li-HSC comprising a WO 3 /C anode and a MOF-NC cathode boasts a large energy density of 159.97 W h kg -1 at a power density of 173.6 W kg -1 and 88.3% of the capacity is retained at a current density of 5 A g -1 after 3000 charging-discharging cycles, which are better than those previously reported for Li-HSCs. The high energy and power densities of the Li-HSCs of WO 3 /C//MOF-NC render large potential in energy storage.

Hierarchical Co-based Porous Layered Double Hydroxide Arrays Derived via Alkali Etching for High-performance Supercapacitors

NASA Astrophysics Data System (ADS)

Abushrenta, Nasser; Wu, Xiaochao; Wang, Junnan; Liu, Junfeng; Sun, Xiaoming

2015-08-01

Hierarchical nanoarchitecture and porous structure can both provide advantages for improving the electrochemical performance in energy storage electrodes. Here we report a novel strategy to synthesize new electrode materials, hierarchical Co-based porous layered double hydroxide (PLDH) arrays derived via alkali etching from Co(OH)2@CoAl LDH nanoarrays. This structure not only has the benefits of hierarchical nanoarrays including short ion diffusion path and good charge transport, but also possesses a large contact surface area owing to its porous structure which lead to a high specific capacitance (23.75 F cm-2 or 1734 F g-1 at 5 mA cm-2) and excellent cycling performance (over 85% after 5000 cycles). The enhanced electrode material is a promising candidate for supercapacitors in future application.

Controllable Fabrication of Amorphous Co-Ni Pyrophosphates for Tuning Electrochemical Performance in Supercapacitors.

PubMed

Chen, Chen; Zhang, Ning; He, Yulu; Liang, Bo; Ma, Renzhi; Liu, Xiaohe

2016-09-07

Incorporation of two transition metals offers an effective method to enhance the electrochemical performance in supercapacitors for transition metal compound based electrodes. However, such a configuration is seldom concerned in pyrophosphates. Here, amorphous phase Co-Ni pyrophosphates are fabricated as electrodes in supercapacitors. Through controllably adjusting the ratios of Co and Ni as well as the calcination temperature, the electrochemical performance can be tuned. An optimized amorphous Ni-Co pyrophosphate exhibits much higher specific capacitance than monometallic Ni and Co pyrophosphates and shows excellent cycling ability. When employing Ni-Co pyrophosphates as positive electrode and activated carbon as a negative electrode, the fabricated asymmetric supercapacitor cell exhibits favorable capacitance and cycling ability. This study provides facile methods to improve the transition metal pyrophosphate electrodes for efficient electrodes in electrochemical energy storage devices.

Hierarchical Co-based Porous Layered Double Hydroxide Arrays Derived via Alkali Etching for High-performance Supercapacitors

PubMed Central

Abushrenta, Nasser; Wu, Xiaochao; Wang, Junnan; Liu, Junfeng; Sun, Xiaoming

2015-01-01

Hierarchical nanoarchitecture and porous structure can both provide advantages for improving the electrochemical performance in energy storage electrodes. Here we report a novel strategy to synthesize new electrode materials, hierarchical Co-based porous layered double hydroxide (PLDH) arrays derived via alkali etching from Co(OH)2@CoAl LDH nanoarrays. This structure not only has the benefits of hierarchical nanoarrays including short ion diffusion path and good charge transport, but also possesses a large contact surface area owing to its porous structure which lead to a high specific capacitance (23.75 F cm−2 or 1734 F g−1 at 5 mA cm−2) and excellent cycling performance (over 85% after 5000 cycles). The enhanced electrode material is a promising candidate for supercapacitors in future application. PMID:26278334

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.

Superior cycle performance and high reversible capacity of SnO2/graphene composite as an anode material for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Liu, Lilai; An, Maozhong; Yang, Peixia; Zhang, Jinqiu

2015-03-01

SnO2/graphene composite with superior cycle performance and high reversible capacity was prepared by a one-step microwave-hydrothermal method using a microwave reaction system. The SnO2/graphene composite was characterized by X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, X-ray photoelectron spectroscopy, transmission electron microscopy and high resolution transmission electron microscopy. The size of SnO2 grains deposited on graphene sheets is less than 3.5 nm. The SnO2/graphene composite exhibits high capacity and excellent electrochemical performance in lithium-ion batteries. The first discharge and charge capacities at a current density of 100 mA g-1 are 2213 and 1402 mA h g-1 with coulomb efficiencies of 63.35%. The discharge specific capacities remains 1359, 1228, 1090 and 1005 mA h g-1 after 100 cycles at current densities of 100, 300, 500 and 700 mA g-1, respectively. Even at a high current density of 1000 mA g-1, the first discharge and charge capacities are 1502 and 876 mA h g-1, and the discharge specific capacities remains 1057 and 677 mA h g-1 after 420 and 1000 cycles, respectively. The SnO2/graphene composite demonstrates a stable cycle performance and high reversible capacity for lithium storage.

Controllable embedding of sulfur in high surface area nitrogen doped three dimensional reduced graphene oxide by solution drop impregnation method for high performance lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

Zegeye, Tilahun Awoke; Tsai, Meng-Che; Cheng, Ju-Hsiang; Lin, Ming-Hsien; Chen, Hung-Ming; Rick, John; Su, Wei-Nien; Kuo, Chung-Feng Jeffrey; Hwang, Bing-Joe

2017-06-01

High capacity lithium-sulfur batteries with stable cycle performance and sulfur loadings greater than 70 wt% are regarded as promising candidates for energy storage devices. However, it has been challenged to achieving practical application of sulfur cathode because of low loading of active sulfur and poor cycle performance. Herein, we design novel nanocomposite cathode materials consist of sulfur (80 wt%) embedded within nitrogen doped three-dimensional reduced graphene oxide (N-3D-rGO) by controllable sulfur-impregnation method. Nitrogen doping helps increase the surface area by ten times from pristine graphene, and pore volume by seven times. These structural features allow the cathode to hold more sulfur. It also adsorbs polysulfides and prevents their detachment from the host materials; thereby achieving stable cycle performance. The solution drop sulfur-impregnation method provides uniform distribution of nano-sulfur in controlled manner. The material delivers a high initial discharge capacity of 1042 mAhg-1 and 916 mAhg-1 with excellent capacity retention of 94.8% and 81.9% at 0.2 C and 0.5 C respectively after 100 cycles. Thus, the combination of solution drop and nitrogen doping opens a new chapter for resolving capacity fading as well as long cycling problems and creates a new strategy to increase sulfur loading in controlled mechanism.

Development and Validation of a Slurry Model for Chemical Hydrogen Storage in Fuel Cell Applications

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

Brooks, Kriston P.; Pires, Richard P.; Simmons, Kevin L.

2014-07-25

The US Department of Energy's (DOE) Hydrogen Storage Engineering Center of Excellence (HSECoE) is developing models for hydrogen storage systems for fuel cell-based light duty vehicle applications for a variety of promising materials. These transient models simulate the performance of the storage system for comparison to the DOE’s Technical Targets and a set of four drive cycles. The purpose of this research is to describe the models developed for slurry-based chemical hydrogen storage materials. The storage systems of both a representative exothermic system based on ammonia borane and endothermic system based on alane were developed and modeled in Simulink®. Oncemore » complete the reactor and radiator components of the model were validated with experimental data. The model was then run using a highway cycle, an aggressive cycle, cold-start cycle and hot drive cycle. The system design was adjusted to meet these drive cycles. A sensitivity analysis was then performed to identify the range of material properties where these DOE targets and drive cycles could be met. Materials with a heat of reaction greater than 11 kJ/mol H2 generated and a slurry hydrogen capacity of greater than 11.4% will meet the on-board efficiency and gravimetric capacity targets, respectively.« less

Preparation and electrochemical properties of mesoporous NiCo2O4 double-hemisphere used as anode for lithium-ion battery.

PubMed

Yang, Yue; Huang, Guo Yong; Sun, Hongyu; Ahmad, Mashkoor; Mou, Qinyao; Zhang, Hongmei

2018-06-19

NiCo 2 O 4 is a potential anode material for lithium ion battery due to its many advantages, such as high theoretical capacitance, low cost, and good electrochemical activity. In this study, mesoporous NiCo 2 O 4 double-hemisphere (3-5 μm) with high surface area (270.68 m 2 ·g -1 ) and excellent electrochemical performances has been synthesized through a facile precipitation method followed with thermal treatment process. The prepared NiCo 2 O 4 is pure phase and can be indexed as a face-centered-cubic with a typical spinel structure. Electrochemical tests show the prepared material has high specific capacities (910 mAh·g -1 at 100 mA·g -1 ), excellent cyclicity (908  mAh·g -1 at 100 mA·g -1 after 60 cycles) and remarkable high rate performance (after 100 cycles, 585 mAh·g -1 at 400 mAh·g -1 , 415 mAh·g -1 at 800 mAh·g -1 and 320 mAh·g -1 at 1600 mAh·g -1 with coulombic efficiencies of almost 100%). The excellent performances of prepared NiCo 2 O 4 are mainly caused by the unique double-hemisphere structure, which has large surface area, gives material more opportunity to contact with electrolyte and facilitates lithium ion spreading into the material along the radical direction, resulting in a promising application for next-generation lithium-ion batteries. Copyright © 2018 Elsevier Inc. All rights reserved.

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.

Ferritin-Triggered Redox Cycling for Highly Sensitive Electrochemical Immunosensing of Protein.

PubMed

Akanda, Md Rajibul; Ju, Huangxian

2018-06-04

Electrochemical immunoassay amplified with redox cycling has become a challenging topic in highly sensitive analysis of biomarkers. Here a ferritin-triggered redox cycling is reported by using a highly outersphere reaction-philic (OSR-philic) redox mediator ruthenium hexamine (Ru(NH3)63+) to perform the OSR-philic/innersphere reaction-philic (ISR-philic) controlled signal amplification. The screened mediator can meet the needs of lower E0 than ferritin, low reactivity with ISR-philic species, and quick electron exchange with ferritin redox couple. The ferritin-labeled antibody is firstly bounded to immunosensor surface by recognizing the target antigen capured by the immobilized primary antibody. The ferritin then mediates OSR-philic/ISR-philic transfer from Ru(NH3)63+/2+/immunosensor to ferritin-H2O2 redox system. The fast mediation and excellent resistant of highly OSR-philic Ru(NH3)63+ against radical oxygen species lead to highly sensitive electrochemical readout and high signal-to-background ratio. The proposed redox cycling greatly enhances the readout signal and the sensitivity of traditional ferritin-labelled sandwich immunoassay. Using Enteropathogenic Coli (E. Coli) antigen as a model analyte, the developed method shows excellent linearity over the concentration range from 10.0 pg/mL to 0.1 µg/mL and a detection limit of 10.0 fg/mL. The acceptable accuracy, good reproducibility and selectivity of the proposed immunoassay method in real samples indicate the superior practicability of the ferritin-triggered redox cycling.

SnCo–CMK nanocomposite with improved electrochemical performance for lithium-ion batteries

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

Zeng, Lingxing; Fujian Key Laboratory of Pollution Control & Resource Reuse, Fuzhou, Fujian 350007; Deng, Cuilin

Highlights: • The SnCo–CMK nanocomposite was synthesized using mesoporous carbon as nano-reactor. • Ultrafine SnCo nanoparticles distribute both inside and outside of mesopore channels. • The SnCo–CMK nanocomposite is an alternative anode material for Li-ion intercalation. • A high reversible capacity of 562 mAh g{sup −1} is maintained after 60 cycles at 100 mA g{sup −1}. - Abstract: In the present work, SnCo–CMK nanocomposite was successfully synthesized for the first time via a simple nanocasting route by using mesoporous carbon as nano-reactor. The nanocomposite was then characterized by means of X-ray diffraction (XRD), thermogravimetric analysis (TG), N{sub 2} adsorption–desorption, scanningmore » and transmission electron microscopy (SEM/TEM) respectively. Furthermore, the SnCo–CMK nanocomposite exhibited large reversible capacities, excellent cycling stability and enhanced rate capability when employed as an anode material for lithium-ion batteries. A large reversible capacity of 562 mA h g{sup −1} was obtained after 60 cycles at a current density of 0.1 A g{sup −1} which is attributed to the structure of ‘meso-nano’ SnCo–CMK composite. This unique structure ensures the intimate contact between CMK and SnCo nanoparticles, buffers the large volume expansion and prevents the aggregation of the SnCo nanoparticles during cycling, leading to the excellent cycling stability and enhanced rate capability.« less

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.

A facile one-step synthesis of Mn{sub 3}O{sub 4} nanoparticles-decorated TiO{sub 2} nanotube arrays as high performance electrode for supercapacitors

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

Zhang, Jianfang; Wang, Yan; Key Laboratory of Advance Functional Materials and Devices of Anhui Province, Hefei 230009

Via a facile one-step chemical bath deposition route, homogeneously dispersed Mn{sub 3}O{sub 4} nanoparticles have been successfully deposited onto the inner surface of TiO{sub 2} nanotube arrays (TNAs). The content and size of Mn{sub 3}O{sub 4} can be controlled by changing the deposition time. Field emission scanning electron microscopy and transmission electron microscopy analysis reveal the morphologies structures of Mn{sub 3}O{sub 4}/TNAs composites. The crystal-line structures are characterized by the X-ray diffraction patterns and Raman spectra. X-ray photoelectron spectroscopy further confirms the valence states of the sample elements. The electrochemical properties of Mn{sub 3}O{sub 4}/TNAs electrodes are systematically investigated bymore » the combine use of cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The resulting Mn{sub 3}O{sub 4}/TNAs electrode prepared by deposition time of 3 h shows the highest specific capacitance of 570 F g{sup −1} at a current density of 1 A g{sup −1}. And it also shows an excellent long-term cycling stability at a current density of 5 A g{sup −1}, which remaining 91.8% of the initial capacitance after 2000 cycles. Thus this kind of Mn{sub 3}O{sub 4} nanoparticles decorated TNAs may be considered as an alternative promising candidate for high performance supercapacitor electrodes. - Graphical abstract: Mn{sub 3}O{sub 4} nanoparticles have been uniformly deposited onto the inner surfaces of TiO{sub 2} nanotube arrays through a facile one-step chemical bath deposition method. As electrodes for supercapacitors, they exhibit a relatively high specific capacity and excellent cycling stability. - Highlights: • Mn{sub 3}O{sub 4} nanoparticles have been deposited onto TiO{sub 2} nanotube arrays by chemical bath deposition. • The Mn{sub 3}O{sub 4}/TNAs exhibits a highest specific capacitance of 570 F g{sup –1} at a current density of 1 A g{sup –1}. • The Mn{sub 3}O{sub 4}/TNAs electrode shows an excellent cycling stability of 91.8% after 2000 cycles.« less

A low cost, high energy density, and long cycle life potassium-sulfur battery for grid-scale energy storage.

PubMed

Lu, Xiaochuan; Bowden, Mark E; Sprenkle, Vincent L; Liu, Jun

2015-10-21

A potassium-sulfur battery using K(+) -conducting beta-alumina as the electrolyte to separate a molten potassium metal anode and a sulfur cathode is presented. The results indicate that the battery can operate at as low as 150 °C with excellent performance. This study demonstrates a new type of high-performance metal-sulfur battery that is ideal for grid-scale energy-storage applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chromium doping as a new approach to improve the cycling performance at high temperature of 5 V LiNi 0.5Mn 1.5O 4-based positive electrode

NASA Astrophysics Data System (ADS)

Aklalouch, Mohamed; Amarilla, José Manuel; Rojas, Rosa M.; Saadoune, Ismael; Rojo, José María

LiCr 2 YNi 0.5- YMn 1.5- YO 4 (0 < Y ≤ 0.2) spinels have been synthesized by a sucrose-aided combustion method. Two sets of Cr-doped samples have been obtained by heating the "as-prepared" samples at 700 and 900 °C for 1 h. X-ray diffraction and thermogravimetric data show that pure and single phase spinels with similar lattice parameter have been synthesized. The homogeneity and the sub-micrometric particle size of the spinels have been shown by SEM and TEM. The main effect of the temperature is to increase the particle size from ≈50 to ≈500 nm, on heating from 700 to 900 °C. The study of the influence of Cr-dopant content and thermal treatment on the electrochemical properties at 25 °C and at 55 °C has been carried out by galvanostatic cycling in Li-cells. The discharge capacity (≈130 mAh g -1) does not noticeably change with the synthesis conditions; but the cycling performances are strongly modified. Key factors that control the cycling performances have been determined. The most highlighted result is that spinels heated at 900 °C with Y ≤ 0.1 have very high capacity retention at 55 °C (>96% after 40 cycles, cyclability >99.9% by cycle) indicating that metal doping is a new approach to prepare 5 V LiNi 0.5Mn 1.5O 5-based cathodes with excellent cycling performances at high temperature.

The facile synthesis of hierarchical NiCoO2 nanotubes comprised ultrathin nanosheets for supercapacitors

NASA Astrophysics Data System (ADS)

Xu, Xin; Zhou, Han; Ding, Shujiang; Li, Jun; Li, Beibei; Yu, Demei

2014-12-01

Hierarchical NiCoO2 nanosheets nanotubes are successfully prepared by a mild solution method based on the template of polymeric nanotubes (PNT) followed by a thermal annealing treatment. The microstructure and chemical composition of NiCoO2 nanosheets nanotubes are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analyzer, X-ray diffraction (XRD) and Thermogravimetric analysis (TGA). When evaluated as an electrode material for supercapacitors, the results of electrochemical test show that the unique NiCoO2 nanosheets nanotubes exhibit relatively high specific capacitance of 1468, 1352, 1233, 1178, 1020 and 672 F g-1 at the discharge current densities of 2, 4, 8, 10, 20 and 40 A g-1, respectively. They also reveal an excellent cycling stability of 99.2% retention after 3000 cycles at 10 A g-1. The smart nanostructures of the NiCoO2 nanosheets nanotubes make a prominent contribution to the excellent electrochemical performance.

Hybrid NiS/CoO mesoporous nanosheet arrays on Ni foam for high-rate supercapacitors

NASA Astrophysics Data System (ADS)

Wu, Jianghong; Ouyang, Canbin; Dou, Shuo; Wang, Shuangyin

2015-08-01

A new hybrid of NiS/CoO porous nanosheets was synthesized on Ni foam by one-step electrodeposition method and used as an electrode for high-performance pseudocapacitance. The as-synthesized NiS/CoO porous nanosheets hybrid shows a high specific capacitance of 1054 F g-1 at a high current density of 6 A g-1, a good rate capability even at high current density (760 F g-1 at 20 A g-1) and a good long-term cycling stability (91.7% of the maximum specific capacitance after 3000 cycles). These excellent properties can be mainly attributed to the unique hierarchical porous structure with large surface area and interspaces which facilitate charge transfer and redox reaction. The enhancement in the interface contact between active material and substrate results in excellent conductivity of the electrode and a strong synergistic effect of NiS and CoO as individual constituents contributed to high capacitance of the hybrid electrode.

Hybrid NiS/CoO mesoporous nanosheet arrays on Ni foam for high-rate supercapacitors.

PubMed

Wu, Jianghong; Ouyang, Canbin; Dou, Shuo; Wang, Shuangyin

2015-08-14

A new hybrid of NiS/CoO porous nanosheets was synthesized on Ni foam by one-step electrodeposition method and used as an electrode for high-performance pseudocapacitance. The as-synthesized NiS/CoO porous nanosheets hybrid shows a high specific capacitance of 1054 F g(-1) at a high current density of 6 A g(-1), a good rate capability even at high current density (760 F g(-1) at 20 A g(-1)) and a good long-term cycling stability (91.7% of the maximum specific capacitance after 3000 cycles). These excellent properties can be mainly attributed to the unique hierarchical porous structure with large surface area and interspaces which facilitate charge transfer and redox reaction. The enhancement in the interface contact between active material and substrate results in excellent conductivity of the electrode and a strong synergistic effect of NiS and CoO as individual constituents contributed to high capacitance of the hybrid electrode.

Bulk antimony sulfide with excellent cycle stability as next-generation anode for lithium-ion batteries

PubMed Central

Yu, Denis Y. W.; Hoster, Harry E.; Batabyal, Sudip K.

2014-01-01

Nanomaterials as anode for lithium-ion batteries (LIB) have gained widespread interest in the research community. However, scaling up and processibility are bottlenecks to further commercialization of these materials. Here, we report that bulk antimony sulfide with a size of 10–20 μm exhibits a high capacity and stable cycling of 800 mAh g−1. Mechanical and chemical stabilities of the electrodes are ensured by an optimal electrode-electrolyte system design, with a polyimide-based binder together with fluoroethylene carbonate in the electrolyte. The polyimide binder accommodates the volume expansion during alloying process and fluoroethylene carbonate suppresses the increase in charge transfer resistance of the electrodes. We observed that particle size is not a major factor affecting the charge-discharge capacities, rate capability and stability of the material. Despite the large particle size, bulk antimony sulfide shows excellent rate performance with a capacity of 580 mAh g−1 at a rate of 2000 mA g−1. PMID:24691396

Preparation of a porous Sn@C nanocomposite as a high-performance anode material for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Zhang, Yanjun; Jiang, Li; Wang, Chunru

2015-07-01

A porous Sn@C nanocomposite was prepared via a facile hydrothermal method combined with a simple post-calcination process, using stannous octoate as the Sn source and glucose as the C source. The as-prepared Sn@C nanocomposite exhibited excellent electrochemical behavior with a high reversible capacity, long cycle life and good rate capability when used as an anode material for lithium ion batteries.A porous Sn@C nanocomposite was prepared via a facile hydrothermal method combined with a simple post-calcination process, using stannous octoate as the Sn source and glucose as the C source. The as-prepared Sn@C nanocomposite exhibited excellent electrochemical behavior with a high reversible capacity, long cycle life and good rate capability when used as an anode material for lithium ion batteries. Electronic supplementary information (ESI) available: Detailed experimental procedure and additional characterization, including a Raman spectrum, TGA curve, N2 adsorption-desorption isotherm, TEM images and SEM images. See DOI: 10.1039/c5nr03093e

High capacity hard carbon derived from lotus stem as anode for sodium ion batteries

NASA Astrophysics Data System (ADS)

Zhang, Nan; Liu, Qing; Chen, Weilun; Wan, Min; Li, Xiaocheng; Wang, Lili; Xue, Lihong; Zhang, Wuxing

2018-02-01

Porous hard carbons are synthesized via carbonizing lotus stems with naturally hierarchical structures. The hard carbon carbonized at 1400 °C (LS1400) delivers a total capacity 350 mAh g-1 in the current density of 100 mA g-1 and a plateau capacity of 250 mAh g-1. Even cycled at 100 mA g-1 after 450 cycles, the capacity still retains 94%. Further investigation shows that the sodium storage of LS carbons involves Na+ adsorption in the defect sites, Na+ insertion and Na metal deposition in the closed pores. However, the Na metal deposition in closed pores mainly contribute to the plateau capacity, leading to the excellent sodium storage performance of LS1400 with a large closed pore ratio of 66%. The results show that the intrinsic structure of natural biomass can inspire us to design hard carbon with large closed pore ratio as excellent anode for sodium ion batteries.

Excellent rate capability and cycling stability in Li+-conductive Li2SnO3-coated LiNi0.5Mn1.5O4 cathode materials for lithium-ion batteries.

PubMed

Mou, Jirong; Deng, Yunlong; Song, Zhicui; Zheng, Qiaoji; Lam, Kwok Ho; Lin, Dunmin

2018-05-22

High-voltage LiNi0.5Mn1.5O4 is a promising cathode candidate for lithium-ion batteries (LIBs) due to its considerable energy density and power density, but the material generally undergoes serious capacity fading caused by side reactions between the active material and organic electrolyte. In this work, Li+-conductive Li2SnO3 was coated on the surface of LiNi0.5Mn1.5O4 to protect the cathode against the attack of HF, mitigate the dissolution of Mn ions during cycling and improve the Li+ diffusion coefficient of the materials. Remarkable improvement in cycling stability and rate performance has been achieved in Li2SnO3-coated LiNi0.5Mn1.5O4. The 1.0 wt% Li2SnO3-coated LiNi0.5Mn1.5O4 cathode exhibits excellent cycling stability with a capacity retention of 88.2% after 150 cycles at 0.1 C and rate capability at high discharge rates of 5 C and 10 C, presenting discharge capacities of 119.5 and 112.2 mAh g-1, respectively. In particular, a significant improvement in cycling stability at 55 °C is obtained after the coating of 1.0 wt% Li2SnO3, giving a capacity retention of 86.8% after 150 cycles at 1 C and 55 °C. The present study provides a significant insight into the effective protection of Li-conductive coating materials for a high-voltage LiNi0.5Mn1.5O4 cathode material.

Hierarchical 3D NiFe2O4@MnO2 core-shell nanosheet arrays on Ni foam for high-performance asymmetric supercapacitors.

PubMed

Zhang, Xinyang; Zhang, Ziqing; Sun, Shuanggan; Sun, Qiushi; Liu, Xiaoyang

2018-02-13

Hierarchical NiFe 2 O 4 @MnO 2 core-shell nanosheet arrays (NSAs) were synthesized on Ni foam as an integrated electrode for supercapacitors, using a facile two-step hydrothermal method followed by calcination treatment. The NiFe 2 O 4 nanosheets were designed as the core and ultrathin MnO 2 nanoflakes as the shell, creating a unique three-dimensional (3D) hierarchical electrode on Ni foam. The composite electrode exhibited remarkable electrochemical performance with a high specific capacitance of 1391 F g -1 at a current density of 2 mA cm -2 and long cycling stability at a high current density of 10 mA cm -2 (only 11.4% loss after 3000 cycles). Additionally, an asymmetric supercapacitor (ASC) device was fabricated with a NiFe 2 O 4 @MnO 2 composite as the positive electrode material and activated carbon (AC) as the negative one. The ASC device exhibited a high energy density (45.2 W h kg -1 ) at a power density of 174 W kg -1 , and an excellent cycling stability over 3000 cycles with 92.5% capacitance retention. The remarkable electrochemical performance demonstrated its great potential as a promising candidate for high-performance supercapacitors.

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.

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.

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.

Porous carbon with a large surface area and an ultrahigh carbon purity via templating carbonization coupling with KOH activation as excellent supercapacitor electrode materials

NASA Astrophysics Data System (ADS)

Sun, Fei; Gao, Jihui; Liu, Xin; Pi, Xinxin; Yang, Yuqi; Wu, Shaohua

2016-11-01

Large surface area and good structural stability, for porous carbons, are two crucial requirements to enable the constructed supercapacitors with high capacitance and long cycling lifespan. Herein, we successfully prepare porous carbon with a large surface area (3175 m2 g-1) and an ultrahigh carbon purity (carbon atom ratio of 98.25%) via templating carbonization coupling with KOH activation. As-synthesized MTC-KOH exhibits excellent performances as supercapacitor electrode materials in terms of high specific capacitance and ultrahigh cycling stability. In a three electrode system, MTC-KOH delivers a high capacitance of 275 F g-1 at 0.5 A g-1 and still 120 F g-1 at a high rate of 30 A g-1. There is almost no capacitance decay even after 10,000 cycles, demonstrating outstanding cycling stability. In comparison, pre-activated MTC with a hierarchical pore structure shows a better rate capability than microporous MTC-KOH. Moreover, the constructed symmetric supercapacitor using MTC-KOH can achieve high energy densities of 8.68 Wh kg-1 and 4.03 Wh kg-1 with the corresponding power densities of 108 W kg-1 and 6.49 kW kg-1, respectively. Our work provides a simple design strategy to prepare highly porous carbons with high carbon purity for supercapacitors application.

A comprehensive approach for diagnosing opportunities for improving the performance of a WWTP.

PubMed

Silva, C; Matos, J Saldanha; Rosa, M J

2016-12-01

High quality services of wastewater treatment require a continuous assessment and improvement of the technical, environmental and economic performance. This paper demonstrates a comprehensive approach for benchmarking wastewater treatment plants (WWTPs), using performance indicators (PIs) and indices (PXs), in a 'plan-do-check-act' cycle routine driven by objectives. The performance objectives herein illustrated were to diagnose the effectiveness and energy performance of an oxidation ditch WWTP. The PI and PX results demonstrated an effective and reliable oxidation ditch (good-excellent performance), and a non-reliable UV disinfection (unsatisfactory-excellent performance) related with influent transmittance and total suspended solids. The energy performance increased with the treated wastewater volume and was unsatisfactory below 50% of plant capacity utilization. The oxidation ditch aeration performed unsatisfactorily and represented 38% of the plant energy consumption. The results allowed diagnosing opportunities for improving the energy and economic performance considering the influent flows, temperature and concentrations, and for levering the WWTP performance to acceptable-good effectiveness, reliability and energy efficiency. Regarding the plant reliability for fecal coliforms, improvement of UV lamp maintenance and optimization of the UV dose applied and microscreen recommissioning were suggested.

Fabrication of nickel-foam-supported layered zinc-cobalt hydroxide nanoflakes for high electrochemical performance in supercapacitors.

PubMed

Yuan, Peng; Zhang, Ning; Zhang, Dan; Liu, Tao; Chen, Limiao; Liu, Xiaohe; Ma, Renzhi; Qiu, Guanzhou

2014-10-04

Nickel foam supported Zn-Co hydroxide nanoflakes were fabricated by a facile solvothermal method. Benefited from the unique structure of Zn-Co hydroxide nanoflakes on a nickel foam substrate, the as prepared materials exhibited an excellent specific capacitance of 901 F g(-1) at 5 A g(-1) and remarkable cycling stability as electrode materials in supercapacitors.

Multidimensional MnO2 nanohair-decorated hybrid multichannel carbon nanofiber as an electrode material for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Jun, Jaemoon; Lee, Jun Seop; Shin, Dong Hoon; Kim, Sung Gun; Jang, Jyongsik

2015-09-01

One-dimensional (1D)-structured nanomaterials represent one of the most attractive candidates for energy-storage systems due to their contribution to design simplicity, fast charge-transportation network, and their allowance for more accessible ion diffusion. In particular, 1D-structured nanomaterials with a highly complex inner-pore configuration enhance functionality by taking advantage of both the hollow and 1D structures. In this study, we report a MnO2 nanohair-decorated, hybrid multichannel carbon nanofiber (Mn_MCNF) fabricated via single-nozzle co-electrospinning of two immiscible polymer solutions, followed by carbonization and redox reactions. With improved ion accessibility, the optimized Mn_MCNF sample (Mn_MCNF_60 corresponding to a reaction duration time of 60 min for optimal MnO2 nanohair growth) exhibited a high specific capacitance of 855 F g-1 and excellent cycling performance with ~87.3% capacitance retention over 5000 cycles.One-dimensional (1D)-structured nanomaterials represent one of the most attractive candidates for energy-storage systems due to their contribution to design simplicity, fast charge-transportation network, and their allowance for more accessible ion diffusion. In particular, 1D-structured nanomaterials with a highly complex inner-pore configuration enhance functionality by taking advantage of both the hollow and 1D structures. In this study, we report a MnO2 nanohair-decorated, hybrid multichannel carbon nanofiber (Mn_MCNF) fabricated via single-nozzle co-electrospinning of two immiscible polymer solutions, followed by carbonization and redox reactions. With improved ion accessibility, the optimized Mn_MCNF sample (Mn_MCNF_60 corresponding to a reaction duration time of 60 min for optimal MnO2 nanohair growth) exhibited a high specific capacitance of 855 F g-1 and excellent cycling performance with ~87.3% capacitance retention over 5000 cycles. Electronic supplementary information (ESI) available: Experimental data includes optical images, TGA, magnified pore distribution curves and supercapacitor device of the MCNF and Mn_MCNF. See DOI: 10.1039/C5NR03616J

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.

Ge/GeO2-Ordered Mesoporous Carbon Nanocomposite for Rechargeable Lithium-Ion Batteries with a Long-Term Cycling Performance.

PubMed

Zeng, Lingxing; Huang, Xiaoxia; Chen, Xi; Zheng, Cheng; Qian, Qingrong; Chen, Qinghua; Wei, Mingdeng

2016-01-13

Germanium-based nanostructures are receiving intense interest in lithium-ion batteries because they have ultrahigh lithium ion storage ability. However, the Germanium-based anodes undergo the considerably large volume change during the charge/discharge processes, leading to a fast capacity fade. In the present work, a Ge/GeO2-ordered mesoporous carbon (Ge/GeO2-OMC) nanocomposite was successfully fabricated via a facile nanocasting route by using mesoporous carbon as a nanoreactor, and was then used as an anode for lithium-ion batteries. Benefited from its unique three-dimensional "meso-nano" structure, the Ge/GeO2-OMC nanocomposite exhibited large reversible capacity, excellent long-time cycling stability and high rate performance. For instance, a large reversible capacity of 1018 mA h g(-1) was obtained after 100 cycles at a current density of 0.1 A g(-1), which might be attributed to the unique structure of the Ge/GeO2-OMC nanocomposite. In addition, a reversible capacity of 492 mA h g(-1) can be retained when cycled to 500 cycles at a current density of 1 A g(-1).

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.

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.

Free-standing Fe2O3 nanomembranes enabling ultra-long cycling life and high rate capability for Li-ion batteries.

PubMed

Liu, Xianghong; Si, Wenping; Zhang, Jun; Sun, Xiaolei; Deng, Junwen; Baunack, Stefan; Oswald, Steffen; Liu, Lifeng; Yan, Chenglin; Schmidt, Oliver G

2014-12-12

With Fe2O3 as a proof-of-concept, free-standing nanomembrane structure is demonstrated to be highly advantageous to improve the performance of Li-ion batteries. The Fe2O3 nanomembrane electrodes exhibit ultra-long cycling life at high current rates with satisfactory capacity (808 mAh g(-1) after 1000 cycles at 2 C and 530 mAh g(-1) after 3000 cycles at 6 C) as well as repeatable high rate capability up to 50 C. The excellent performance benefits particularly from the unique structural advantages of the nanomembranes. The mechanical feature can buffer the strain of lithiation/delithiation to postpone the pulverization. The two-dimensional transport pathways in between the nanomembranes can promote the pseudo-capacitive type storage. The parallel-laid nanomembranes, which are coated by polymeric gel-like film and SEI layer with the electrolyte in between layers, electrochemically behave like numerous "mini-capacitors" to provide the pseudo-capacitance thus maintain the capacity at high rate.

Porous hollow Co3O4 with rhombic dodecahedral structures for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Zhang, Yi-Zhou; Wang, Yang; Xie, Ye-Lei; Cheng, Tao; Lai, Wen-Yong; Pang, Huan; Huang, Wei

2014-11-01

Porous hollow Co3O4 with rhombic dodecahedral structures were prepared by the calcination of ZIF-67 ([Co(mim)2; mim = 2-methylimidazolate]) rhombic dodecahedral microcrystals. A supercapacitor was successfully constructed by adopting the resulting porous hollow Co3O4 rhombic dodecahedral structure as the electrode material, which showed a large specific capacitance of 1100 F g-1 and retained more than 95.1% of the specific capacitance after 6000 continuous charge-discharge cycles. The excellent capacitive properties and stability mark the porous hollow Co3O4 with the rhombic dodecahedral structure as one of the most promising electrode materials for high-performance supercapacitors.Porous hollow Co3O4 with rhombic dodecahedral structures were prepared by the calcination of ZIF-67 ([Co(mim)2; mim = 2-methylimidazolate]) rhombic dodecahedral microcrystals. A supercapacitor was successfully constructed by adopting the resulting porous hollow Co3O4 rhombic dodecahedral structure as the electrode material, which showed a large specific capacitance of 1100 F g-1 and retained more than 95.1% of the specific capacitance after 6000 continuous charge-discharge cycles. The excellent capacitive properties and stability mark the porous hollow Co3O4 with the rhombic dodecahedral structure as one of the most promising electrode materials for high-performance supercapacitors. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04782f

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.

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.

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.

Electrodeposited three-dimensional Ni-Si nanocable arrays as high performance anodes for lithium ion batteries.

PubMed

Liu, Hao; Hu, Liangbin; Meng, Ying Shirley; Li, Quan

2013-11-07

A configuration of three-dimensional Ni-Si nanocable array anodes is proposed to overcome the severe volume change problem of Si during the charging-discharging process. In the fabrication process, a simple and low cost electrodeposition is employed to deposit Si instead of the common expansive vapor phase deposition methods. The optimum composite nanocable array electrode achieves a high specific capacity ~1900 mA h g(-1) at 0.05 C. After 100 cycles at 0.5 C, 88% of the initial capacity (~1300 mA h g(-1)) remains, suggesting its good capacity retention ability. The high performance of the composite nanocable electrode is attributed to its excellent adhesion of the active material on the three-dimensional current collector and short ionic/electronic transport pathways during cycling.

High performance sodium-ion hybrid capacitor based on Na2Ti2O4(OH)2 nanostructures

NASA Astrophysics Data System (ADS)

Babu, Binson; Shaijumon, M. M.

2017-06-01

Hybrid Na-ion capacitors bridge the performance gap between Na-ion batteries and supercapacitors and offer excellent energy and power characteristics. However, designing efficient anode and cathode materials with improved kinetics and long cycle life is essential for practical implementation of this technology. Herein, layered sodium titanium oxide hydroxide, Na2Ti2O4(OH)2, synthesized through hydrothermal technique, is studied as efficient anode material for hybrid Na-ion capacitor. Half-cell electrochemical studies vs. Na/Na+ showed excellent performance for Na2Ti2O4(OH)2 electrode, with ∼57.2% of the total capacity (323.3 C g-1 at 1.0 mV s-1) dominated by capacitive behavior and the remaining due to Na-intercalation. The obtained values are in good agreement with Trasatti plots indicating the potential of this material as efficient anode for hybrid Na-ion capacitor. Further, a full cell Na-ion capacitor is fabricated with Na2Ti2O4(OH)2 as anode and chemically activated Rice Husk Derived Porous Carbon (RHDPC-KOH) as cathode by using organic electrolyte. The hybrid device, operated at a maximum cell voltage of 4 V, exhibits stable electrochemical performance with a maximum energy density of ∼65 Wh kg-1 (at 500 W kg-1, 0.20 A g-1) and with more than ∼ 93% capacitive retention after 3000 cycles.

NiCo2S4 nanotube arrays grown on flexible nitrogen-doped carbon foams as three-dimensional binder-free integrated anodes for high-performance lithium-ion batteries.

PubMed

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

2016-02-14

Binary metal sulfides, especially NiCo2S4, hold great promise as anode materials for high-performance lithium-ion batteries because of their excellent electronic conductivity and high capacity compared to mono-metal sulfides and oxides. Here, NiCo2S4 nanotube arrays are successfully grown on flexible nitrogen-doped carbon foam (NDCF) substrates with robust adhesion via a facile surfactant-assisted hydrothermal route and the subsequent sulfurization treatment. The obtained NiCo2S4/NDCF composites show unique three-dimensional architectures, in which NiCo2S4 nanotubes of ∼5 μm in length and 100 nm in width are uniformly grown on the NDCF skeletons to form arrays. When used directly as integrated anodes for lithium-ion batteries without any conductive additives and binders, the NiCo2S4/NDCF composites exhibit a high reversible capacity of 1721 mA h g(-1) at a high current density of 500 mA g(-1), enhanced cycling performance with the capacity maintained at 1182 mA h g(-1) after 100 cycles, and a remarkable rate capability. The excellent lithium storage performances of the composites could be attributed to the unique material composition, a rationally designed hollow nanostructure and an integrated smart architecture, which offer fast electron transport and ion diffusion, enhanced material/-electrolyte contact area and facile accommodation of strains during the lithium insertion and extraction process.

A high-performance supercapacitor electrode based on N-doped porous graphene

NASA Astrophysics Data System (ADS)

Dai, Shuge; Liu, Zhen; Zhao, Bote; Zeng, Jianhuang; Hu, Hao; Zhang, Qiaobao; Chen, Dongchang; Qu, Chong; Dang, Dai; Liu, Meilin

2018-05-01

The development of high-performance supercapacitors (SCs) often faces some contradictory and competing requirements such as excellent rate capability, long cycling life, and high energy density. One effective strategy is to explore electrode materials of high capacitance, electrode architectures of fast charge and mass transfer, and electrolytes of wide voltage window. Here we report a facile and readily scalable strategy to produce high-performance N-doped graphene with a high specific capacitance (∼390 F g-1). A symmetric SC device with a wide voltage window of 3.5 V is also successfully fabricated based on the N-doped graphene electrode. More importantly, the as-assembled symmetric SC delivers a high energy density of 55 Wh kg-1 at a power density of 1800 W kg-1 while maintaining superior cycling life (retaining 96.6% of the initial capacitance after 20,000 cycles). Even at a power density as high as 8800 W kg-1, it still retains an energy density of 29 Wh kg-1, higher than those of previously reported graphene-based symmetric SCs.

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.

A Nanocrystalline Fe2O3 Film Anode Prepared by Pulsed Laser Deposition for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Teng, Xiaoling; Qin, Youzhi; Wang, Xia; Li, Hongsen; Shang, Xiantao; Fan, Shuting; Li, Qiang; Xu, Jie; Cao, Derang; Li, Shandong

2018-02-01

Nanocrystalline Fe2O3 thin films are deposited directly on the conduct substrates by pulsed laser deposition as anode materials for lithium-ion batteries. We demonstrate the well-designed Fe2O3 film electrodes are capable of excellent high-rate performance (510 mAh g- 1 at high current density of 15,000 mA g- 1) and superior cycling stability (905 mAh g- 1 at 100 mA g- 1 after 200 cycles), which are among the best reported state-of-the-art Fe2O3 anode materials. The outstanding lithium storage performances of the as-synthesized nanocrystalline Fe2O3 film are attributed to the advanced nanostructured architecture, which not only provides fast kinetics by the shortened lithium-ion diffusion lengths but also prolongs cycling life by preventing nanosized Fe2O3 particle agglomeration. The electrochemical performance results suggest that this novel Fe2O3 thin film is a promising anode material for all-solid-state thin film batteries.

Delving into sensible measures to enhance the environmental performance of biohydrogen: A quantitative approach based on process simulation, life cycle assessment and data envelopment analysis.

PubMed

Martín-Gamboa, Mario; Iribarren, Diego; Susmozas, Ana; Dufour, Javier

2016-08-01

A novel approach is developed to evaluate quantitatively the influence of operational inefficiency in biomass production on the life-cycle performance of hydrogen from biomass gasification. Vine-growers and process simulation are used as key sources of inventory data. The life cycle assessment of biohydrogen according to current agricultural practices for biomass production is performed, as well as that of target biohydrogen according to agricultural practices optimised through data envelopment analysis. Only 20% of the vineyards assessed operate efficiently, and the benchmarked reduction percentages of operational inputs range from 45% to 73% in the average vineyard. The fulfilment of operational benchmarks avoiding irregular agricultural practices is concluded to improve significantly the environmental profile of biohydrogen (e.g., impact reductions above 40% for eco-toxicity and global warming). Finally, it is shown that this type of bioenergy system can be an excellent replacement for conventional hydrogen in terms of global warming and non-renewable energy demand. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Significantly enhanced robustness and electrochemical performance of flexible carbon nanotube-based supercapacitors by electrodepositing polypyrrole

NASA Astrophysics Data System (ADS)

Chen, Yanli; Du, Lianhuan; Yang, Peihua; Sun, Peng; Yu, Xiang; Mai, Wenjie

2015-08-01

Here, we report robust, flexible CNT-based supercapacitor (SC) electrodes fabricated by electrodepositing polypyrrole (PPy) on freestanding vacuum-filtered CNT film. These electrodes demonstrate significantly improved mechanical properties (with the ultimate tensile strength of 16 MPa), and greatly enhanced electrochemical performance (5.6 times larger areal capacitance). The major drawback of conductive polymer electrodes is the fast capacitance decay caused by structural breakdown, which decreases cycling stability but this is not observed in our case. All-solid-state SCs assembled with the robust CNT/PPy electrodes exhibit excellent flexibility, long lifetime (95% capacitance retention after 10,000 cycles) and high electrochemical performance (a total device volumetric capacitance of 4.9 F/cm3). Moreover, a flexible SC pack is demonstrated to light up 53 LEDs or drive a digital watch, indicating the broad potential application of our SCs for portable/wearable electronics.

Effect of reduced graphene oxide on the energy harvesting performance of P(VDF-TrFE)-BaTiO3 nanocomposite devices

NASA Astrophysics Data System (ADS)

Yaqoob, Usman; Chung, Gwiy-Sang

2017-09-01

This study investigates the effect of reduced graphene oxide (rGO) on the energy harvesting performance of poly(vinylidenefluoride-trifluoroethylene)-barium titanate (P(VDF-TrFE)-BTO) nanocomposite devices. Several piezoelectric nanogenerators with different rGO contents were prepared, among them PBR5-NG (rGO = 0.5%) exhibited maximum output performance. PBR5-NG showed a maximum open circuit voltage of 8.5 Vpk-pk and short circuit current of 2 μApk-pk at an applied force of 2 N. Moreover, PBR5-NG displayed an output power of 4.5 μW at 2 MΩ load resistance. To confirm device stability, the fabricated device was subjected to several pressing-releasing cycles. The device had excellent stability, even after 1000 pressing-releasing cycles. Together, our results indicate that our fabricated PBR5-NG is a promising energy source for future flexible electronics.

Porous carbon nanosheets from coal tar for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

He, Xiaojun; Ma, Hao; Wang, Jingxian; Xie, Yuanyang; Xiao, Nan; Qiu, Jieshan

2017-07-01

A hydroxide-template strategy coupled with in-situ chemical activation is reported for the first time to fabricate porous carbon nanosheets (PCNSs) from coal tar. The thin PCNSs feature abundant short pores accessible for fast ion transport and high specific surface area up to 3235 m2 g-1 for ion adsorption. As electrodes for supercapacitors, the PCNSs show a high capacitance of 296.2 F g-1 at 0.05 A g-1 in 6 M KOH electrolyte, an excellent rate performance with a capacitance of 220.7 F g-1 at 20 A g-1 and a superior cycle stability with over 97.2% capacitance retention after 11000 charge-discharge cycles at 3.5 A g-1. This work paves a new way for efficient fabrication of sheet-like carbon materials with tuned porous structure from polycyclic aromatic hydrocarbons for high performance supercapacitors.

A Novel Graphene-Polysulfide Anode Material for High-Performance Lithium-Ion Batteries

PubMed Central

Ai, Wei; Xie, Linghai; Du, Zhuzhu; Zeng, Zhiyuan; Liu, Juqing; Zhang, Hua; Huang, Yunhui; Huang, Wei; Yu, Ting

2013-01-01

We report a simple and efficient approach for fabrication of novel graphene-polysulfide (GPS) anode materials, which consists of conducting graphene network and homogeneously distributed polysulfide in between and chemically bonded with graphene sheets. Such unique architecture not only possesses fast electron transport channels, shortens the Li-ion diffusion length but also provides very efficient Li-ion reservoirs. As a consequence, the GPS materials exhibit an ultrahigh reversible capacity, excellent rate capability and superior long-term cycling performance in terms of 1600, 550, 380 mAh g−1 after 500, 1300, 1900 cycles with a rate of 1, 5 and 10 A g−1 respectively. This novel and simple strategy is believed to work broadly for other carbon-based materials. Additionally, the competitive cost and low environment impact may promise such materials and technique a promising future for the development of high-performance energy storage devices for diverse applications. PMID:23903017

Oxygen-rich hierarchical porous carbon derived from artemia cyst shells with superior electrochemical performance.

PubMed

Zhao, Yufeng; Ran, Wei; He, Jing; Song, Yanfang; Zhang, Chunming; Xiong, Ding-Bang; Gao, Faming; Wu, Jinsong; Xia, Yongyao

2015-01-21

In this study, three-dimensional (3D) hierarchical porous carbon with abundant functional groups is produced through a very simple low-cost carbonization of Artemia cyst shells. The unique hierarchical porous structure of this material, combining large numbers of micropores and macropores, as well as reasonable amount of mesopores, is proven favorable to capacitive behavior. The abundant oxygen functional groups from the natural carbon precursor contribute stable pseudocapacitance. As-prepared sample exhibits high specific capacitance (369 F g(-1) in 1 M H2SO4 and 349 F g(-1) in 6 M KOH), excellent cycling stability with capacitance retention of 100% over 10 000 cycles, and promising rate performance. This work not only describes a simple way to produce high-performance carbon electrode materials for practical application, but also inspires an idea for future structure design of porous carbon.

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.

Flower-like NiO structures: Controlled hydrothermal synthesis and electrochemical characteristic

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

Chai, Hui; Chen, Xuan; Key Laboratory of Advanced Functional Materials, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang

Graphical abstract: Flower-like porous NiO was obtained via thermal decomposition of the precursor prepared by a hydrothermal process using hexamethylenetetramine and polyethylene glycol as hydrolysis-controlling agent and surfactant, respectively. The morphology and microstructure of as-synthesized NiO were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results of electrochemical measurements demonstrated that the flower-like porous NiO has high capacity (340 F g{sup −1}) with excellent cycling performance as electrode materials of electrochemical capacitors (ECs), which may be attributed to the unique microstrcture of NiO. Data analyses indicated that NiO with novel porousmore » structure attractive for practical and large-scale applications in electrochemical capacitors. Display Omitted Highlights: ► Synthesis and characterization of NiO with novel porous structure is presented in this work. ► The electrochemical performance of product was examined. ► NiO with excellent performance as electrode materials may be due to the unique microstrcture. ► NiO with novel porous structure attractive for practical with high capacity (340 F g{sup −1}). -- Abstract: Flower-like porous NiO was obtained by thermal decomposition of the precursor prepared by a hydrothermal process with hexamethylenetetramine and polyethylene glycol as hydrolysis-controlling agent and surfactant, respectively. The morphology and microstructure of as-synthesized NiO were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The resulting structures of NiO exhibited porous like petal building blocks. The electrochemical measurements’ results demonstrated that flower-like porous NiO has high capacity (340 F g{sup −1}) with excellent cycling performance as electrode materials for electrochemical capacitors, which may be attributed to the unique structure of NiO. The results indicated that NiO with novel porous structure has been attractive for practical and large-scale applications in electrochemical capacitors.« less

High-capacity FeTiO3/C negative electrode for sodium-ion batteries with ultralong cycle life

NASA Astrophysics Data System (ADS)

Ding, Changsheng; Nohira, Toshiyuki; Hagiwara, Rika

2018-06-01

The development of electrode materials which improve both the energy density and cycle life is one of the most challenging issues facing the practical application of sodium-ion batteries today. In this work, FeTiO3/C nanoparticles are synthesized as negative electrode materials for sodium-ion batteries. The electrochemical performance and charge-discharge mechanism of the FeTiO3/C negative electrode are investigated in an ionic liquid electrolyte at 90 °C. The FeTiO3/C negative electrode delivers a high reversible capacity of 403 mAh g-1 at a current rate of 10 mA g-1, and exhibits high rate capability and excellent cycling stability for up to 2000 cycles. The results indicate that FeTiO3/C is a promising negative electrode material for sodium-ion batteries.

Perylene-Based All-Organic Redox Battery with Excellent Cycling Stability.

PubMed

Iordache, Adriana; Delhorbe, Virginie; Bardet, Michel; Dubois, Lionel; Gutel, Thibaut; Picard, Lionel

2016-09-07

Organic materials derived from biomass can constitute a viable option as replacements for inorganic materials in lithium-ion battery electrodes owing to their low production costs, recyclability, and structural diversity. Among them, conjugated carbonyls have become the most promising type of organic electrode material as they present high theoretical capacity, fast reaction kinetics, and quasi-infinite structural diversity. In this letter, we report a new perylene-based all-organic redox battery comprising two aromatic conjugated carbonyl electrode materials, the prelithiated tetra-lithium perylene-3,4,9,10-tetracarboxylate (PTCLi6) as negative electrode material and the poly(N-n-hexyl-3,4,9,10-perylene tetracarboxylic)imide (PTCI) as positive electrode material. The resulting battery shows promising long-term cycling stability up to 200 cycles. In view of the enhanced cycling performances, the two organic materials studied herein are proposed as suitable candidates for the development of new all-organic lithium-ion batteries.

Facile fabrication of CNTs@C@MoSe2@Se hybrids with amorphous structure for high performance anode in lithium-ion batteries.

PubMed

Jin, Rencheng; Cui, Yuming; Wang, Qingyao; Li, Guihua

2017-12-15

Amorphous MoSe 2 and Se anchored on amorphous carbon coated multiwalled carbon nanotubes (CNTs@C@MoSe 2 @Se) have been synthesized by a facile solvothermal strategy. The one dimensional CNTs@C@MoSe 2 @Se can effectively buffer the volume variation, prohibit the aggregation and facilitate electron and ion transport throughout the electrode. Furthermore, the combination of MoSe 2 and Se also provides buffer spaces for the volumetric change during cycling. Thus, the obtained CNTs@C@MoSe 2 @Se hybrids display the enhanced cycle stability and excellent high rate capacity. The reversible capacity of 1010mAhg -1 can be achieved after 100 cycles at the current density of 0.1Ag -1 . Even after 500 cycles, a reversible capacity of 508mAhg -1 is still retained at 5Ag -1 . Copyright © 2017 Elsevier Inc. All rights reserved.

Flexible free-standing TiO2/graphene/PVdF films as anode materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Ren, H. M.; Ding, Y. H.; Chang, F. H.; He, X.; Feng, J. Q.; Wang, C. F.; Jiang, Y.; Zhang, P.

2012-12-01

Graphene composites were prepared by hydrothermal method using titanium dioxide (TiO2) adsorbed graphene oxide (GO) sheets as precursors. Free-standing hybrid films for lithium-ion batteries were prepared by adding TiO2/graphene composites to the polyvinylidene fluoride (PVdF)/N-methyl-2-pyrrolidone (NMP) solution, followed by a solvent evaporation technique. These films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and various electrochemical techniques. Flexible films show an excellent cycling performance, which was attributed to the interconnected graphene conducting network, which depressed the increasing of electric resistance during the cycling.

Free-standing ultrathin CoMn2O4 nanosheets anchored on reduced graphene oxide for high-performance supercapacitors.

PubMed

Gao, Guoxin; Lu, Shiyao; Xiang, Yang; Dong, Bitao; Yan, Wei; Ding, Shujiang

2015-11-21

Ultrathin CoMn2O4 nanosheets supported on reduced graphene oxide (rGO) are successfully synthesized through a simple co-precipitation method with a post-annealing treatment. With the assistance of citrate, the free-standing CoMn2O4 ultrathin nanosheets can form porous overlays on both sides of the rGO sheets. Such a novel hybrid nanostructure can effectively promote charge transport and accommodate volume variation upon prolonged charge/discharge cycling. When evaluated as a promising electrode for supercapacitors in a 6 M KOH solution electrolyte, the hybrid nanocomposites demonstrate highly enhanced capacitance and excellent cycling stability.

Polymer-pyrolysis assisted synthesis of vanadium trioxide and carbon nanocomposites as high performance anode materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Dong, Yucheng; Ma, Ruguang; Hu, Mingjun; Cheng, Hua; Lee, Jong-Min; Li, Yang Yang; Zapien, Juan Antonio

2014-09-01

We present a simple polymer-pyrolysis assisted method to prepare vanadium trioxide and carbon nanocomposites as an advanced anode material for lithium-ion batteries. The as-prepared material deliver a superior battery performance with highly retained capacity of ∼780 mAh g-1 over 100 cycles at a current density of 200 mA g-1, showing excellent cyclic stability, and good rate capability. The improved electrochemical performance of vanadium trioxide and carbon nanocomposites electrode makes it promising as a suitable anode material for practical battery applications.

Novel secondary assembled micro/nano porous spheres ZnCo2O4 with superior electrochemical performances as lithium ion anode material.

PubMed

Liu, Haowen; Hu, Qihong

2018-08-10

In this work, novel secondary assembled micro/nano porous spheres ZnCo 2 O 4 were firstly prepared by combining the hydrothermal method with post-synthesis calcinations. The structure and morphology of the obtained powder were characterized by x-ray powder diffraction and field emission-scanning electron microscopy. As the anode material of lithium-ion half-cells, the as-prepared ZnCo 2 O 4 delivered a very high capacity, extra cycling stability and excellent rate capability. A discharge capacity of 950 mAh g -1 with up to 99.7% retention corresponding to the second cycle at 0.1 C was achieved after 90 cycles, which was an improved cyclability over previous reports. The higher current charge-discharge and electrochemical impedance spectroscopy data indicate that the material's integrity was maintained. Therefore constructing the secondary assembled 3D micro/nano structure is an effective strategy to obtain the superior electrochemical performances.

Asymmetric supercapacitors with high energy density based on helical hierarchical porous NaxMnO2 and MoO2 † †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc03326h Click here for additional data file.

PubMed Central

Lu, Xue-Feng; Huang, Zhi-Xiang; Tong, Ye-Xiang

2016-01-01

Helical hierarchical porous NaxMnO2/CC and MoO2/CC, which are assembled from nanosheets and nanoparticles, respectively, are fabricated using a simple electrodeposition method. These unique helical porous structures enable electrodes to have a high capacitance and an outstanding cycling performance. Based on the helical NaxMnO2/CC as the positive electrodes and helical MoO2/CC as the negative electrodes, high performance NaxMnO2/CC//MoO2/CC asymmetric supercapacitors (ASCs) are successfully assembled, and they achieve a maximum volume C sp of 2.04 F cm–3 and a maximum energy density of 0.92 mW h cm–3 for the whole device and an excellent cycling stability with 97.22% C sp retention after 6000 cycles. PMID:28791103

Synthesis of nitrogen-doped mesoporous carbon from polyaniline with an F127 template for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Xin, Guoxiang; Wang, Yanhui; Jia, Shaopei; Tian, Pengfei; Zhou, Shuyu; Zang, Jianbing

2017-11-01

N-doped mesoporous carbons (N-MCs) were synthesized via the oxypolymerization of aniline with a Pluronic F127 template, sintering at 850 °C in N2 atmosphere, and activation in a KOH solution. The contrast experiments were carried out without the addition of F127 and the obtained sample was defined as N-Cs. The Brunaner-Emmett-Teller measurement, pore size distribution measurements, transmission electron microscopy, and X-ray photoelectron spectroscopy of N-MCs and N-Cs were performed. The specific areas of the N-MCs and N-Cs reached 721 and 394 m2 g-1, respectively. The specific capacitances of the N-MCs and N-Cs were as high as 318 and 106 F g-1 at 0.2 A g-1. The cycle life of N-MCs at different current densities was above 96% after 5000 cycles of charging and discharging, indicating that the N-MCs had excellent cycle stability.

One-Dimensional Cu2- xSe Nanorods as the Cathode Material for High-Performance Aluminum-Ion Battery.

PubMed

Jiang, Jiali; Li, He; Fu, Tao; Hwang, Bing-Joe; Li, Xue; Zhao, Jinbao

2018-05-30

In this work, nonstoichiometric Cu 2- x Se fabricated by a facile water evaporation process is used as high-performance Al-ion battery cathode materials. Cu 2- x Se electrodes show high reversible capacity and excellent cycling stability, even at a high current density of 200 mA g -1 , the specific charge capacity in the initial cycle is 241 mA h g -1 and maintains 100 mA h g -1 after 100 cycles with a Coulombic efficiency of 96.1%, showing good capacity retention. The prominent kinetics of Cu 2- x Se electrodes is also revealed by the GITT, which is attributed to the ultrahigh electronic conductivity of the Cu 2- x Se material. Most importantly, an extensive research is dedicated to investigating the detailed intercalation and de-intercalation of relatively large chloroaluminate anions into the cubic Cu 2- x Se, which is conducive to better understand the reaction mechanism of the Al/Cu 2- x Se battery.

Greatly Suppressed Shuttle Effect for Improved Lithium Sulfur Battery Performance through Short Chain Intermediates.

PubMed

Xu, Na; Qian, Tao; Liu, Xuejun; Liu, Jie; Chen, Yu; Yan, Chenglin

2017-01-11

The high solubility of long-chain lithium polysulfides and their infamous shuttle effect in lithium sulfur battery lead to rapid capacity fading along with low Coulombic efficiency. To address above issues, we propose a new strategy to suppress the shuttle effect for greatly enhanced lithium sulfur battery performance mainly through the formation of short-chain intermediates during discharging, which allows significant improvements including high capacity retention of 1022 mAh/g with 87% retention for 450 cycles. Without LiNO 3 -containing electrolytes, the excellent Coulombic efficiency of ∼99.5% for more than 500 cycles is obtained, suggesting the greatly suppressed shuttle effect. In situ UV/vis analysis of electrolyte during cycling reveals that the short-chain Li 2 S 2 and Li 2 S 3 polysulfides are detected as main intermediates, which are theoretically verified by density functional theory (DFT) calculations. Our strategy may open up a new avenue for practical application of lithium sulfur battery.

Performance and Ageing Robustness of Graphite/NMC Pouch Prototypes Manufactured through Eco-Friendly Materials and Processes.

PubMed

Loeffler, Nicholas; Kim, Guk-T; Passerini, Stefano; Gutierrez, Cesar; Cendoya, Iosu; De Meatza, Iratxe; Alessandrini, Fabrizio; Appetecchi, Giovanni B

2017-09-22

Graphite/lithium nickel-manganese-cobalt oxide (NMC), stacked pouch cells with nominal capacity of 15-18 Ah were designed, developed, and manufactured for automotive applications in the frame of the European Project GREENLION. A natural, water-soluble material was used as the main electrode binder, thus allowing the employment of H 2 O as the only processing solvent. The electrode formulations were developed, optimized, and upscaled for cell manufacturing. Prolonged cycling and ageing tests revealed excellent capacity retention and robustness toward degradation phenomena. For instance, above 99 % of the initial capacity is retained upon 500 full charge/discharge cycles, corresponding to a fading of 0.004 % per cycle, and about 80 % of the initial capacity is delivered after 8 months ageing at 45 °C. The stacked soft-packaged cells have shown very reproducible characteristics and performance, reflecting the goodness of design and manufacturing. © 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.

A two-step hydrothermal synthesis approach to synthesize NiCo2S4/NiS hollow nanospheres for high-performance asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Xu, Rui; Lin, Jianming; Wu, Jihuai; Huang, Miaoliang; Fan, Leqing; He, Xin; Wang, Yiting; Xu, Zedong

2017-11-01

In this work, a high-performance asymmetric supercapacitor device based on NiCo2S4/NiS hollow nanospheres as the positive electrode and the porous activated carbon as the negative electrode was successfully fabricated via a facile two-step hydrothermal synthesis approach. This NiCo2S4/NiS//activated carbon asymmetric supercapacitor achieved a high energy density of 43.7 Wh kg-1 at a power density of 160 W kg-1, an encouraging specific capacitance of 123 F g-1 at a current density of 1 mA cm-2, as well as a long-term performance with capacitance degradation of 5.2% after 3000 consecutive cycles at 1 mA cm-2. Moreover, the NiCo2S4/NiS electrode also demonstrated an excellent specific capacitance (1947.5 F g-1 at 3 mA cm-2) and an outstanding cycling stability (retaining 90.3% after 1000 cycles). The remarkable electrochemical performances may be attributed to the effect of NiS doping on NiCo2S4 which could enlarge the surface area and increase the surface roughness.

In-situ chemical reduction produced graphene paper for flexible supercapacitors with impressive capacitive performance

NASA Astrophysics Data System (ADS)

Ye, Xingke; Zhu, Yucan; Tang, Zhonghua; Wan, Zhongquan; Jia, Chunyang

2017-08-01

For practical applications of graphene-based materials in flexible supercapacitors, a technological breakthrough is currently required to fabricate high-performance graphene paper by a facile method. Herein, highly conductive (∼6900 S m-1) graphene paper with loose multilayered structure is produced by a high-efficiency in-situ chemical reduction process, which assembles graphite oxide suspensions into film and simultaneously conducts chemical reduction. Graphene papers with different parameters (including different types and doses of reductants, different thicknesses and areas of films) are successfully fabricated through this in-situ chemical reduction method. Meanwhile, the influences of the graphene papers with different parameters upon the supercapacitor performance are systematically investigated. Flexible supercapacitor based on the graphene paper exhibits high areal capacitance (152.4 mF cm-2 at current density of 2.0 mA cm-2 in aqueous electrolyte), and excellent rate performance (88.7% retention at 8.0 mA cm-2). Furthermore, bracelet-shaped all-solid supercapacitor with fascinating cycling stability (96.6% retention after 10 000 cycles) and electrochemical stability (an almost negligible capacity loss under different bending states and 99.6% retention after 4000 bending cycles) is established by employing the graphene paper electrode material and polymer electrolyte.

Sustainable Sulfur-rich Copolymer/Graphene Composite as Lithium-Sulfur Battery Cathode with Excellent Electrochemical Performance

PubMed Central

Ghosh, Arnab; Shukla, Swapnil; Khosla, Gaganpreet Singh; Lochab, Bimlesh; Mitra, Sagar

2016-01-01

A sulfur-rich copolymer, poly(S-r-C-a) has been synthesized via a sustainable route, showing the utility of two major industrial wastes- elemental sulfur (petroleum waste) and cardanol (agro waste), to explore its potential as cathode material for Li-S batteries. The sulfur-rich copolymer exhibited a reduction in the active material dissolution into the electrolyte and a low self-discharge rate behavior during the rest time compared to an elemental sulfur cathode, indicating the chemical confinement of sulfur units. The presence of organosulfur moieties in copolymer suppress the irreversible deposition of end-discharge products on electrode surfaces and thus improve the electrochemical performances of Li-S batteries. This sulfur copolymer offered a reversible capacity of 892 mA h g−1 at 2nd cycle and maintained the capacity of 528 mA h g−1 after 50 cycles at 200 mA g−1. Reduced graphene oxide (rGO) prepared via a sustainable route was used as a conductive filler to extract the better electrochemical performances from this sulfur copolymer. Such sustainable origin batteries prepared via economically viable showed an improved specific capacity of ~975 mA h g−1 after 100 cycles at 200 mA g−1 current rate with capacity fading of 0.15% per cycle and maintained a stable performance over 500 cycles at 2000 mA g−1. PMID:27121089

Superior cycle performance and high reversible capacity of SnO2/graphene composite as an anode material for lithium-ion batteries

PubMed Central

Liu, Lilai; An, Maozhong; Yang, Peixia; Zhang, Jinqiu

2015-01-01

SnO2/graphene composite with superior cycle performance and high reversible capacity was prepared by a one-step microwave-hydrothermal method using a microwave reaction system. The SnO2/graphene composite was characterized by X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, X-ray photoelectron spectroscopy, transmission electron microscopy and high resolution transmission electron microscopy. The size of SnO2 grains deposited on graphene sheets is less than 3.5 nm. The SnO2/graphene composite exhibits high capacity and excellent electrochemical performance in lithium-ion batteries. The first discharge and charge capacities at a current density of 100 mA g−1 are 2213 and 1402 mA h g−1 with coulomb efficiencies of 63.35%. The discharge specific capacities remains 1359, 1228, 1090 and 1005 mA h g−1 after 100 cycles at current densities of 100, 300, 500 and 700 mA g−1, respectively. Even at a high current density of 1000 mA g−1, the first discharge and charge capacities are 1502 and 876 mA h g−1, and the discharge specific capacities remains 1057 and 677 mA h g−1 after 420 and 1000 cycles, respectively. The SnO2/graphene composite demonstrates a stable cycle performance and high reversible capacity for lithium storage. PMID:25761938

Coaxial CoMoO4 nanowire arrays with chemically integrated conductive coating for high-performance flexible all-solid-state asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Chen, Yaping; Liu, Borui; Liu, Qi; Wang, Jun; Li, Zhanshuang; Jing, Xiaoyan; Liu, Lianhe

2015-09-01

Flexible all-solid-state supercapacitors have offered promising applications as novel energy storage devices based on their merits, such as small size, low cost, light weight and high wearability for high-performance portable electronics. However, one major challenge to make flexible all-solid-state supercapacitors depends on the improvement of electrode materials with higher electrical conductivity properties and longer cycling stability. In this article, we put forward a simple strategy to in situ synthesize 1D CoMoO4 nanowires (NWs), using highly conductive CC and an electrically conductive PPy wrapping layer on CoMoO4 NW arrays for high performance electrode materials. The results show that the CoMoO4/PPy hybrid NW electrode exhibits a high areal specific capacitance of ca. 1.34 F cm-2 at a current density of 2 mA cm-2, which is remarkably better than the corresponding values for a pure CoMoO4 NW electrode of 0.7 F cm-2. An excellent cycling performance of nanocomposites of up to 95.2% (ca. 1.12 F cm-2) is achieved after 2000 cycles compared to pristine CoMoO4 NWs. In addition, we fabricate flexible all-solid-state ASC which can be cycled reversibly in the voltage range of 0-1.7 V, and exhibits a maximum energy density of 104.7 W h kg-1 (3.522 mW h cm-3), demonstrating great potential for practical applications in flexible energy storage electronics.Flexible all-solid-state supercapacitors have offered promising applications as novel energy storage devices based on their merits, such as small size, low cost, light weight and high wearability for high-performance portable electronics. However, one major challenge to make flexible all-solid-state supercapacitors depends on the improvement of electrode materials with higher electrical conductivity properties and longer cycling stability. In this article, we put forward a simple strategy to in situ synthesize 1D CoMoO4 nanowires (NWs), using highly conductive CC and an electrically conductive PPy wrapping layer on CoMoO4 NW arrays for high performance electrode materials. The results show that the CoMoO4/PPy hybrid NW electrode exhibits a high areal specific capacitance of ca. 1.34 F cm-2 at a current density of 2 mA cm-2, which is remarkably better than the corresponding values for a pure CoMoO4 NW electrode of 0.7 F cm-2. An excellent cycling performance of nanocomposites of up to 95.2% (ca. 1.12 F cm-2) is achieved after 2000 cycles compared to pristine CoMoO4 NWs. In addition, we fabricate flexible all-solid-state ASC which can be cycled reversibly in the voltage range of 0-1.7 V, and exhibits a maximum energy density of 104.7 W h kg-1 (3.522 mW h cm-3), demonstrating great potential for practical applications in flexible energy storage electronics. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02961a

High-Performance Cells Containing Lithium Metal Anodes, LiNi0.6Co0.2Mn0.2O2 (NCM 622) Cathodes, and Fluoroethylene Carbonate-Based Electrolyte Solution with Practical Loading.

PubMed

Salitra, Gregory; Markevich, Elena; Afri, Michal; Talyosef, Yosef; Hartmann, Pascal; Kulisch, Joern; Sun, Yang-Kook; Aurbach, Doron

2018-06-13

We report on the highly stable lithium metal|LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM 622) cells with practical electrodes' loading of 3.3 mA h g -1 , which can undergo many hundreds of stable cycles, demonstrating high rate capability. A key issue was the use of fluoroethylene carbonate (FEC)-based electrolyte solutions (1 M LiPF 6 in FEC/dimethyl carbonate). Li|NCM 622 cells can be cycled at 1.5 mA cm -2 for more than 600 cycles, whereas symmetric Li|Li cells demonstrate stable performance for more than 1000 cycles even at higher areal capacity and current density. We attribute the excellent performance of both Li|NCM and Li|Li cells to the formation of a stable and efficient solid electrolyte interphase (SEI) on the surface of the Li metal electrodes cycled in FEC-based electrolyte solutions. The composition of the SEI on the Li and the NCM electrodes is analyzed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. A drastic capacity fading of Li|NCM cells is observed, followed by spontaneous capacity recovery during prolonged cycling. This phenomenon depends on the current density and the amount of the electrolyte solution and relates to kinetic limitations because of SEI formation on the Li anodes in the FEC-based electrolyte solution.

The effect of gradient boracic polyanion-doping on structure, morphology, and cycling performance of Ni-rich LiNi0.8Co0.15Al0.05O2 cathode material

NASA Astrophysics Data System (ADS)

Chen, Tao; Li, Xiang; Wang, Hao; Yan, Xinxiu; Wang, Lei; Deng, Bangwei; Ge, Wujie; Qu, Meizhen

2018-01-01

A gradient boracic polyanion-doping method is applied to Ni-rich LiNi0.8Co0.15Al0.05O2 (NCA) cathode material in this study to suppress the capacity/potential fade during charge-discharge cycling. Scanning electron microscope (SEM) results show that all samples present spherical morphology and the secondary particle size increases with increasing boron content. X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) results demonstrate that boracic polyanions are successfully introduced into the bulk material and more enriched in the outer layer. XPS analysis further reveals that the valence state of Ni3+ is partly reduced to Ni2+ at the surface due to the incorporation of boracic polyanions. From the electrochemical measurements, B0.015-NCA electrode exhibits excellent cycling performance, even at high potential and elevated temperature. Moreover, the SEM images illustrate the presence of cracks and a thick SEI layer on pristine particles after 100 cycles at high temperature, while the B0.015-NCA particles show an intact structure and thin SEI layer. Electrochemical impedance spectroscopy confirms that the boracic polyanion doping could hinder the impedance increase during cycling at elevated temperature. These results clearly indicate that the gradient boracic polyanion-doping contributes to the remarkable enhancement of structure stability and cycling performance of NCA.

Low Cost Metal Carbide Nanocrystals as Binding and Electrocatalytic Sites for High Performance Li-S Batteries.

PubMed

Zhou, Fei; Li, Zheng; Luo, Xuan; Wu, Tong; Jiang, Bin; Lu, Lei-Lei; Yao, Hong-Bin; Antonietti, Markus; Yu, Shu-Hong

2018-02-14

Lithium sulfur (Li-S) batteries are considered as promising energy storage systems for the next generation of batteries due to their high theoretical energy densities and low cost. Much effort has been made to improve the practical energy densities and cycling stability of Li-S batteries via diverse designs of materials nanostructure. However, achieving simultaneously good rate capabilities and stable cycling of Li-S batteries is still challenging. Herein, we propose a strategy to utilize a dual effect of metal carbide nanoparticles decorated on carbon nanofibers (MC NPs-CNFs) to realize high rate performance, low hysteresis, and long cycling stability of Li-S batteries in one system. The adsorption experiments of lithium polysulfides (LiPS) to MC NPs and corresponding theoretical calculations demonstrate that LiPS are likely to be adsorbed and diffused on the surface of MC NPs because of their moderate chemical bonding. MC NPs turn out to have also an electrocatalytic role and accelerate electrochemical redox reactions of LiPS, as proven by cyclic voltammetry analysis. The fabricated Li-S batteries based on the W 2 C NPs-CNFs hybrid electrodes display not only high specific capacity of 1200 mAh/g at 0.2C but also excellent rate performance and cycling stability, for example, a model setup can be operated at 1C for 500 cycles maintaining a final specific capacity of 605 mAh/g with a degradation rate as low as 0.06%/cycle.

A hierarchical architecture S/MWCNT nanomicrosphere with large pores for lithium sulfur batteries.

PubMed

Chen, Jia-jia; Zhang, Qian; Shi, Yi-ning; Qin, Lin-lin; Cao, Yong; Zheng, Ming-sen; Dong, Quan-feng

2012-04-28

A hierarchical S/MWCNT nanomicrosphere for lithium/sulfur batteries with a high power and energy density as well as an excellent cycle life is introduced. Sulfur was uniformly coated on the surface of functional MWCNTs, which serves as a carbon matrix, to form a typical nanoscale core-shell structure with a sulfur layer of thickness 10-20 nm. Then the nanoscale sulfur intermediate composite was ball-milled to form interwoven and porous sphere architecture with large pores (around 1 μm to 5 μm). Different from most sulfur/carbon materials with micropore and mesopore structure, the micrometre scale S/MWCNT nanomicrosphere with a large pore structure could also exhibit high sulfur utilization and cycle retention. It could maintain a reversible capacity of 1000 mA h g(-1) after 100 cycles at 0.3 A g(-1) current density. And it even remained 780 mA h g(-1) after 200 cycles at 0.5 A g(-1) and 650 mA h g(-1) after 200 cycles at 1 A g(-1), showing a significant cyclability enhancement. It is believed that under the collective effect of hierarchical architecture, as well as the existence of carboxyl functional groups, sulfur/carbon materials with large pores could also exhibit an excellent electrochemical performance. The synthesis process introduced here is simple and broadly applicable, which would not only be beneficial to design new materials for lithium sulfur batteries but can also be extended to many different electrode materials for lithium ion batteries. This journal is © the Owner Societies 2012

Research@ARL. Imaging & Image Processing. Volume 3, Issue 1

DTIC Science & Technology

2014-01-01

goal, the focal plane arrays (FPAs) the Army deploys must excel in all areas of performance including thermal sensitivity, image resolution, speed of...are available only in relatively small sizes. Further, the difference in thermal expansion coefficients between a CZT substrate and its silicon (Si...read-out integrated circuitry reduces the reliability of large format FPAs due to repeated thermal cycling. Some in the community believed this

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.

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.

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

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.

High-Performance Hydrogen Storage Nanoparticles Inside Hierarchical Porous Carbon Nanofibers with Stable Cycling.

PubMed

Xia, Guanglin; Chen, Xiaowei; Zhao, Yan; Li, Xingguo; Guo, Zaiping; Jensen, Craig M; Gu, Qinfen; Yu, Xuebin

2017-05-10

An effective route based on space-confined chemical reaction to synthesize uniform Li 2 Mg(NH) 2 nanoparticles is reported. The hierarchical pores inside the one-dimensional carbon nanofibers (CNFs), induced by the creation of well-dispersed Li 3 N, serve as intelligent nanoreactors for the reaction of Li 3 N with Mg-containing precursors, resulting in the formation of uniformly discrete Li 2 Mg(NH) 2 nanoparticles. The nanostructured Li 2 Mg(NH) 2 particles inside the CNFs are capable of complete hydrogenation and dehydrogenation at a temperature as low as 105 °C with the suppression of ammonia release. Furthermore, by virtue of the nanosize effects and space-confinement by the porous carbon scaffold, no degradation was observed after 50 de/rehydrogenation cycles at a temperature as low as 130 °C for the as-prepared Li 2 Mg(NH) 2 nanoparticles, indicating excellent reversibility. Moreover, the theoretical calculations demonstrate that the reduction in particle size could significantly enhance the H 2 sorption of Li 2 Mg(NH) 2 by decreasing the relative activation energy barrier, which agrees well with our experimental results. This method could represent an effective, general strategy for synthesizing nanoparticles of complex hydrides with stable reversibility and excellent hydrogen storage performance.

Electrochemical properties of graphene nanosheets/polyaniline nanofibers composites as electrode for supercapacitors

NASA Astrophysics Data System (ADS)

Li, Jing; Xie, Huaqing; Li, Yang; Liu, Jie; Li, Zhuxin

Graphene nanosheets/polyaniline nanofibers (GNS/PANI) composites are synthesized via in situ polymerization of aniline monomer in HClO 4 solution. The PANI nanofibers homogeneously coating on the surface of GNS greatly improve the charge transfer reaction. The GNS/PANI composites exhibit better electrochemical performances than the pure individual components. A remarkable specific capacitance of 1130 F g -1 (based on GNS/PANI composites) is obtained at a scan rate of 5 mV s -1 in 1 M H 2SO 4 solution compared to 402 F g -1 for pure PANI and 270 F g -1 for GNS. The excellent performance is not only due to the GNS which can provide good electrical conductivity and high specific surface area, but also associate with a good redox activity of ordered PANI nanofibers. Moreover, the GNS/PANI composites present excellent long cycle life with 87% specific capacitance retained after 1000 charge/discharge processes. The resulting composites are promising electrode materials for high-performance electrical energy storage devices.

Highly Conductive Aromatic Functionalized Multi-Walled Carbon Nanotube for Inkjet Printable High Performance Supercapacitor Electrodes

PubMed Central

Attri, Pankaj

2015-01-01

We report the functionalization of multiwalled carbon nanotubes (MWCNT) via the 1,3-dipolar [3+2] cycloaddition of aromatic azides, which resulted in a detangled CNT as shown by transmission electron microscopy (TEM). Carboxylic moieties (-COOH) on aromatic azide result in highly stable aqueous dispersion (max. conc. ~ 10 mg/mL H2O), making the suitable for inkjet printing. Printed patterns on polyethylene terephthalate (PET) flexible substrate exhibit low sheet resistivity ~65 Ω. cm, which is attributed to enhanced conductivity. Fabricated Supercapacitors (SC) assembled using these printed substrates exhibit good electrochemical performance in organic as well as aqueous electrolytes. High energy and power density (57.8 Wh/kg and 0.85 kW/kg) in 1M H2SO4 aqueous electrolyte demonstrate the excellent performance of the proposed supercapacitor. Capacitive retention varies from ~85–94% with columbic efficiency ~95% after 1000 charge/discharge cycles in different electrolytes, demonstrating the excellent potential of the device for futuristic power applications. PMID:26153688

Au-embedded ZnO/NiO hybrid with excellent electrochemical performance as advanced electrode materials for supercapacitor.

PubMed

Zheng, Xin; Yan, Xiaoqin; Sun, Yihui; Bai, Zhiming; Zhang, Guangjie; Shen, Yanwei; Liang, Qijie; Zhang, Yue

2015-02-04

Here we design a nanostructure by embedding Au nanoparticles into ZnO/NiO core-shell composites as supercapacitors electrodes materials. This optimized hybrid electrodes exhibited an excellent electrochemical performance including a long-term cycling stability and a maximum specific areal capacitance of 4.1 F/cm(2) at a current density of 5 mA/cm(2), which is much higher than that of ZnO/NiO hierarchical materials (0.5 F/cm(2)). Such an enhanced property is attributed to the increased electro-electrolyte interfaces, short electron diffusion pathways and good electrical conductivity. Apart from this, electrons can be temporarily trapped and accumulated at the Fermi level (EF') because of the localized schottky barrier at Au/NiO interface in charge process until fill the gap between ZnO and NiO, so that additional electrons can be released during discharge. These results demonstrate that suitable interface engineering may open up new opportunities in the development of high-performance supercapacitors.

Shape control of Co3O4 micro-structures for high-performance gas sensor

NASA Astrophysics Data System (ADS)

Zhou, Qu; Zeng, Wen

2018-01-01

Recently, spinel cobalt oxide (Co3O4) structure has been widely investigated due to its excellent sensitivity towards various noxious gases and good response/recovery speed at low concentration. In this work, we designed and synthesized two kinds of different Co3O4 micro-structure (cube and octahedron) with a similar size. After fabricating them into gas sensors, we found that the crystal plane structure of Co3O4 has an important effect on its gas sensing performance. Furthermore, the {111} planes of Co3O4may be more sensitive than {100} planes to various testing gases. Co3O4 octahedrons micro-structure exhibits an excellent sensitivity (about 12.6), good response/recovery speed and cycling stability (no decline even after 2 days) under 50 ppm ethanol gases at working temperature of 200 °C. As such, thisCo3O4 octahedrons micro-structure is a promising candidate for a high-performance gas sensing material.

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.

Novel topotactically transformed carbon-CoO-NiO-NiCo₂O₄ nanosheet hybrid hetero-structured arrays as ultrahigh performance supercapacitors.

PubMed

Wang, Hai; Guo, Junling; Qing, Chen; Sun, Daming; Wang, Bixiao; Tang, Yiwen

2014-08-14

A novel carbon-CoO-NiO-NiCo2O4 integrated electrode has been designed by reducing the hetero-structured NiCo2O4 nanosheet array with C2H2 on the nickel foam at a low temperature of 350 °C. The topotactical transformation from NiCo2O4 to the integrated electrode has been first conceived and investigated. Such unique nanoarchitectures exhibit excellent electrochemical performance with ultrahigh capacitance and desirable cycle life at high rates.

Binder-free LiCoO2/carbon nanotube cathodes for high-performance lithium ion batteries.

PubMed

Luo, Shu; Wang, Ke; Wang, Jiaping; Jiang, Kaili; Li, Qunqing; Fan, Shoushan

2012-05-02

Binder-free LiCoO(2) -SACNT cathodes with excellent flexibility and conductivity are obtained by constructing a continuous three-dimensional super-aligned carbon nanotube (SACNT) framework with embedded LiCoO(2) particles. These binder-free cathodes display much better cycling stability, greater rate performance, and higher energy density than classical cathodes with binder. Various functional binder-free SACNT composites can be mass produced by the ultrasonication and co-deposition method described in this paper. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Micro-sized organometallic compound of ferrocene as high-performance anode material for advanced lithium-ion batteries

NASA Astrophysics Data System (ADS)

Liu, Zhen; Feng, Li; Su, Xiaoru; Qin, Chenyang; Zhao, Kun; Hu, Fang; Zhou, Mingjiong; Xia, Yongyao

2018-01-01

An organometallic compound of ferrocene is first investigated as a promising anode for lithium-ion batteries. The electrochemical properties of ferrocene are conducted by galvanostatic charge and discharge. The ferrocene anode exhibits a high reversible capacity and great cycling stability, as well as superior rate capability. The electrochemical reaction of ferrocene is semi-reversible and some metallic Fe remains in the electrode even after delithiation. The metallic Fe formed in electrode and the stable solid electrolyte interphase should be responsible for its excellent electrochemical performance.

Solar spectral irradiance variability in cycle 24: observations and models

NASA Astrophysics Data System (ADS)

Marchenko, Sergey V.; DeLand, Matthew T.; Lean, Judith L.

2016-12-01

Utilizing the excellent stability of the Ozone Monitoring Instrument (OMI), we characterize both short-term (solar rotation) and long-term (solar cycle) changes of the solar spectral irradiance (SSI) between 265 and 500 nm during the ongoing cycle 24. We supplement the OMI data with concurrent observations from the Global Ozone Monitoring Experiment-2 (GOME-2) and Solar Radiation and Climate Experiment (SORCE) instruments and find fair-to-excellent, depending on wavelength, agreement among the observations, and predictions of the Naval Research Laboratory Solar Spectral Irradiance (NRLSSI2) and Spectral And Total Irradiance REconstruction for the Satellite era (SATIRE-S) models.

Preparation of Ce- and La-Doped Li4Ti5O12 Nanosheets and Their Electrochemical Performance in Li Half Cell and Li4Ti5O12/LiFePO4 Full Cell Batteries

PubMed Central

Qin, Meng; Li, Yueming; Lv, Xiao-Jun

2017-01-01

This work reports on the synthesis of rare earth-doped Li4Ti5O12 nanosheets with high electrochemical performance as anode material both in Li half and Li4Ti5O12/LiFePO4 full cell batteries. Through the combination of decreasing the particle size and doping by rare earth atoms (Ce and La), Ce and La doped Li4Ti5O12 nanosheets show the excellent electrochemical performance in terms of high specific capacity, good cycling stability and excellent rate performance in half cells. Notably, the Ce-doped Li4Ti5O12 shows good electrochemical performance as anode in a full cell which LiFePO4 was used as cathode. The superior electrochemical performance can be attributed to doping as well as the nanosized particle, which facilitates transportation of the lithium ion and electron transportation. This research shows that the rare earth doped Li4Ti5O12 nanosheets can be suitable as a high rate performance anode material in lithium-ion batteries. PMID:28632167

Nitrogen-doped 3D flower-like carbon materials derived from polyimide as high-performance anode materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Wu, Qiong; Liu, Jiaqi; Yuan, Chenpei; Li, Qiang; Wang, Heng-guo

2017-12-01

Nitrogen-doped 3D flower-like carbon materials (NFCs) have been fabricated using a simple and effective strategy, namely, the hierarchical assembly of polyimide (PI) and subsequent thermal treatment. The effect of pyrolysis temperature on the structural evolution process of PI is also investigated systematically. When evaluated as anode materials for lithium ion batteries (LIBs), the as-obtained NFCs, especially NFCs-550, exhibit good electrochemical performance, including a high reversible capacity (1488.1 mAh g-1 at 0.05 A g-1), excellent rate performance (287.6 mAh g-1 at 2 A g-1), and good cycling stability (645 mAh g-1 with 96% retention after 300 cycles at 0.1 A g-1). The good electrochemical performance is attributed to the synergistic effect between 3D flower-like nanostructure and high nitrogen content. This approach may provide some inspiration to construct a series of heteroatom doped and hierarchical structured carbon materials using polymers for LIBs.

Sustainable, heat-resistant and flame-retardant cellulose-based composite separator for high-performance lithium ion battery

PubMed Central

Zhang, Jianjun; Yue, Liping; Kong, Qingshan; Liu, Zhihong; Zhou, Xinhong; Zhang, Chuanjian; Xu, Quan; Zhang, Bo; Ding, Guoliang; Qin, Bingsheng; Duan, Yulong; Wang, Qingfu; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

2014-01-01

A sustainable, heat-resistant and flame-retardant cellulose-based composite nonwoven has been successfully fabricated and explored its potential application for promising separator of high-performance lithium ion battery. It was demonstrated that this flame-retardant cellulose-based composite separator possessed good flame retardancy, superior heat tolerance and proper mechanical strength. As compared to the commercialized polypropylene (PP) separator, such composite separator presented improved electrolyte uptake, better interface stability and enhanced ionic conductivity. In addition, the lithium cobalt oxide (LiCoO2)/graphite cell using this composite separator exhibited better rate capability and cycling retention than that for PP separator owing to its facile ion transport and excellent interfacial compatibility. Furthermore, the lithium iron phosphate (LiFePO4)/lithium cell with such composite separator delivered stable cycling performance and thermal dimensional stability even at an elevated temperature of 120°C. All these fascinating characteristics would boost the application of this composite separator for high-performance lithium ion battery. PMID:24488228

Facile Synthesis of Three-Dimensional Heteroatom-Doped and Hierarchical Egg-Box-Like Carbons Derived from Moringa oleifera Branches for High-Performance Supercapacitors.

PubMed

Cai, Yijin; Luo, Ying; Xiao, Yong; Zhao, Xiao; Liang, Yeru; Hu, Hang; Dong, Hanwu; Sun, Luyi; Liu, Yingliang; Zheng, Mingtao

2016-12-07

In this paper, we demonstrate that Moringa oleifera branches, a renewable biomass waste with abundant protein content, can be employed as novel precursor to synthesize three-dimensional heteroatom-doped and hierarchical egg-box-like carbons (HEBLCs) by a facile room-temperature pretreatment and direct pyrolysis process. The as-prepared HEBLCs possess unique egg-box-like frameworks, high surface area, and interconnected porosity as well as the doping of heteroatoms (oxygen and nitrogen), endowing its excellent electrochemical performances (superior capacity, high rate capability, and outstanding cycling stability). Therefore, the resultant HEBLC manifests a maximum specific capacitance of 355 F g -1 at current density of 0.5 A g -1 and remarkable rate performance. Moreover, 95% of capacitance retention of HEBLCs can be also achieved after 20 000 charge-discharge cycles at an extremely high current density (20 A g -1 ), indicating a prominent cycling stability. Furthermore, the as-assembled HEBLC//HEBLC symmetric supercapacitor displays a superior energy density of 20 Wh kg -1 in aqueous electrolyte and remarkable capacitance retention (95.6%) after 10 000 charge-discharge cycles. This work provides an environmentally friendly and reliable method to produce higher-valued carbon nanomaterials from renewable biomass wastes for energy storage applications.

Enhanced kinetics of polysulfide redox reactions on Mo2C/CNT in lithium-sulfur batteries.

PubMed

Razaq, Rameez; Sun, Dan; Xin, Ying; Li, Qian; Huang, Taizhong; Zheng, Lei; Zhang, Zhaoliang; Huang, Yunhui

2018-07-20

Among different energy storage devices, the lithium-sulfur (Li-S) battery is the subject of recent attention. However, the capacity decay caused by polysulfide shuttle leading to sluggish kinetics of polysulfide redox reactions is the main hindrance for its practical application in Li-S batteries. Herein, molybdenum carbide nanoparticles anchored on carbon nanotubes (Mo 2 C/CNT) are reported to serve as an efficient cathode material to enhance the electrochemical kinetics of polysulfide conversion in Li-S batteries. Mo 2 C/CNT shows strong adsorption and activation of polar polysulfides and therefore accelerates the redox kinetics of polysulfides, reduces the energy barrier, effectively mitigates the polarization and polysulfide shuttle, thus improving the electrochemical performance. The S-Mo 2 C/CNT composite with 70 wt% sulfur loading exhibits high specific discharge capacity (1206 mA h g -1 at 0.5 C), excellent high-rate performance, long cycle life (900 cycles), and outstanding Coulombic efficiency (∼100%) at a high rate (2 C) corresponding to a capacity decay of only 0.05%. Remarkably, the S-Mo 2 C/CNT cathode with high areal sulfur loading of 2.5 mg cm -2 exhibits high-rate capacities and stable cycling performance over 100 cycles, offering the potential for use in high energy Li-S batteries.

Enhanced kinetics of polysulfide redox reactions on Mo2C/CNT in lithium–sulfur batteries

NASA Astrophysics Data System (ADS)

Razaq, Rameez; Sun, Dan; Xin, Ying; Li, Qian; Huang, Taizhong; Zheng, Lei; Zhang, Zhaoliang; Huang, Yunhui

2018-07-01

Among different energy storage devices, the lithium–sulfur (Li–S) battery is the subject of recent attention. However, the capacity decay caused by polysulfide shuttle leading to sluggish kinetics of polysulfide redox reactions is the main hindrance for its practical application in Li–S batteries. Herein, molybdenum carbide nanoparticles anchored on carbon nanotubes (Mo2C/CNT) are reported to serve as an efficient cathode material to enhance the electrochemical kinetics of polysulfide conversion in Li–S batteries. Mo2C/CNT shows strong adsorption and activation of polar polysulfides and therefore accelerates the redox kinetics of polysulfides, reduces the energy barrier, effectively mitigates the polarization and polysulfide shuttle, thus improving the electrochemical performance. The S-Mo2C/CNT composite with 70 wt% sulfur loading exhibits high specific discharge capacity (1206 mA h g‑1 at 0.5 C), excellent high-rate performance, long cycle life (900 cycles), and outstanding Coulombic efficiency (∼100%) at a high rate (2 C) corresponding to a capacity decay of only 0.05%. Remarkably, the S-Mo2C/CNT cathode with high areal sulfur loading of 2.5 mg cm‑2 exhibits high-rate capacities and stable cycling performance over 100 cycles, offering the potential for use in high energy Li–S batteries.

A honeycomb-like porous carbon derived from pomelo peel for use in high-performance supercapacitors.

PubMed

Liang, Qinghua; Ye, Ling; Huang, Zheng-Hong; Xu, Qiang; Bai, Yu; Kang, Feiyu; Yang, Quan-Hong

2014-11-21

A cost-effective approach to obtain electrode materials with excellent electrochemical performance is critical to the development of supercapacitors (SCs). Here we report the preparation of a three-dimensional (3D) honeycomb-like porous carbon (HLPC) by the simple carbonization of pomelo peel followed by KOH activation. Structural characterization indicates that the as-prepared HLPC with a high specific surface area (SSA) up to 2725 m(2) g(-1) is made up of interconnected microporous carbon walls. Chemical analysis shows that the HLPC is doped with nitrogen and also has oxygen-containing groups. Electrochemical measurements show that the HLPC not only exhibits a high specific capacitance of 342 F g(-1) and 171 F cm(-3) at 0.2 A g(-1) but also shows considerable rate capability with a retention of 62% at 20 A g(-1) as well as good cycling performance with 98% retention over 1000 cycles at 10 A g(-1) in 6 M KOH. Furthermore, an as-fabricated HLPC-based symmetric SC device delivers a maximum energy density of ∼9.4 Wh kg(-1) in the KOH electrolyte. Moreover, the outstanding cycling stability (only 2% capacitance decay over 1000 cycles at 5 A g(-1)) of the SC device makes it promising for use in a high-performance electrochemical energy system.

Cycle stability of the electrochemical capacitors patterned with vertically aligned carbon nanotubes in an LiPF6-based electrolyte.

PubMed

Chiou, Yi-Deng; Tsai, Dah-Shyang; Lam, Hoa Hung; Chang, Chuan-hua; Lee, Kuei-Yi; Huang, Ying-Sheng

2013-09-07

The miniature ultracapacitors, with interdigitated electrodes of vertically aligned carbon nanotubes (VACNTs) and an inter-electrode gap of 20 μm, have been prepared in the LiPF6 organic electrolyte with and without PVdF-HFP gel. PVdF-HFP between two opposing electrodes enhances the device reliability, but lessens its power performance because of the extra diffusion resistance. Also noteworthy are the gel influences on the cycle stability. When the applied voltage is 2.0 or 2.5 V, both the LiPF6 and the gel capacitors exhibit excellent stability, typified by a retention ratio of ≥95% after 10,000 cycles. Their coulombic efficiencies quickly rise up, and hold steady at 100%. Nonetheless, when the applied voltage is 3.5 or 4.0 V, the cycle stability deteriorates, since the negative electrode potential descends below 0.9 V (vs. Li), leading to electrolyte decomposition and SEI formation. For the LiPF6 capacitor, its retention ratio could be around 60% after 10,000 cycles and the coulombic efficiency of 100% is difficult to reach throughout its cycle life. On the other hand, the gel capacitor cycles energy with a much higher retention ratio, >80% after 10,000 cycles, and a better coulombic efficiency, even though electrolyte decomposition still occurs. We attribute the superior stability of the gel capacitor to its extra diffusion resistance which slows down the performance deterioration.

Improvement of the overall performances of LiMn{sub 2}O{sub 4} via surface-modification by polypyrrole

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

Wang, Ting; Wang, Wan; Zhu, Ding

2015-11-15

Graphical abstract: Polypyrrole(PPy) film has improved the rate performance of LiMn{sub 2}O{sub 4} efficiently due to its excellent conductivity. PPy@LiMn{sub 2}O{sub 4} could provide more energy under the higher power than pristine LMO. - Highlights: • The PPy layer on the surface of LMO particles hasn’t been studied in LiMn{sub 2}O{sub 4} so far. • The solvent in the synthesis process of PPy@LMO is absolute ethyl alcohol. • The differences of surface-modification between the PPy and PI for LMO. • The analyses of rate performances are through specific power. - Abstract: Polypyrrole (PPy) is an excellent conductive polymer and themore » study on its utilization in the surface modification of the LiMn{sub 2}O{sub 4} (LMO) is few. In this work, the structure, morphology and electrochemical performance of surface-modified LiMn{sub 2}O{sub 4} composites with PPy and polyimides (PI) were discussed. The crystal structure, chemical bonds and morphology were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. Moreover, the specific power and cycling performance were tested at room and high (55 °C) temperature. The PPy@LMO (surface-modified LMO composites with PPy) shows better performances than the pristine LMO. The addition of PPy not only weakens the corrosion caused by electrolyte, but also improves the discharge capacity at higher rates. The charge transfer resistance of the PPy@LMO is much lower than that of the pristine LMO after cycling.« less

Reduced Graphene Oxide/Tin-Antimony Nanocomposites as Anode Materials for Advanced Sodium-Ion Batteries.

PubMed

Ji, Liwen; Zhou, Weidong; Chabot, Victor; Yu, Aiping; Xiao, Xingcheng

2015-11-11

Reduced graphene oxides loaded with tin-antimony alloy (RGO-SnSb) nanocomposites were synthesized through a hydrothermal reaction and the subsequent thermal reduction treatments. Transmission electron microscope images confirm that SnSb nanoparticles with an average size of about 20-30 nm are uniformly dispersed on the RGO surfaces. When they were used as anodes for rechargeable sodium (Na)-ion batteries, these as-synthesized RGO-SnSb nanocomposite anodes delivered a high initial reversible capacity of 407 mAh g(-1), stable cyclic retention for more than 80 cycles and excellent cycle stability at ultra high charge/discharge rates up to 30C. The significantly improved performance of the synthesized RGO-SnSb nanocomposites as Na-ion battery anodes can be attributed to the synergetic effects of RGO-based flexible framework and the nanoscale dimension of the SnSb alloy particles (<30 nm). Nanosized intermetallic SnSb compounds can exhibit improved structural stability and conductivity during charge and discharge reactions compared to the corresponding individuals (Sn and Sb particles). In the meantime, RGO sheets can tightly anchor SnSb alloy particles on the surfaces, which can not only effectively suppress the agglomeration of SnSb particles but also maintain excellent electronic conduction. Furthermore, the mechanical flexibility of the RGO phase can accommodate the volume expansion and contraction of SnSb particles during the prolonged cycling, therefore, improve the electrode integrity mechanically and electronically. All of these contribute to the electrochemical performance improvements of the RGO-SnSb nanocomposite-based electrodes in rechargeable Na-ion batteries.

Fe3O4/C composite with hollow spheres in porous 3D-nanostructure as anode material for the lithium-ion batteries

NASA Astrophysics Data System (ADS)

Yang, Zhao; Su, Danyang; Yang, Jinping; Wang, Jing

2017-09-01

3d transition-metal oxides, especially Fe3O4, as anode materials for the lithium-ion batteries have been attracting intensive attentions in recent years due to their high energy capacity and low toxicity. A new Fe3O4/C composite with hollow spheres in porous three-dimensional (3D) nanostructure, which was synthesized by a facile solvothermal method using FeCl3·6H2O and porous spongy carbon as raw materials. The specific surface area and microstructures of composite were characterized by nitrogen adsorption-desorption isotherm method, FE-SEM and HR-TEM. A homogeneous distribution of hollow Fe3O4 spheres (diameter ranges from 120 nm to 150 nm) in the spongy carbon (pore size > 200 nm) conductive 3D-network significantly reduced the lithium-ion diffusion length and increased the electrochemical reaction area, and further more enhanced the lithium ion battery performance, such as discharge capacity and cycle life. As an anode material for the lithium-ion battery, the title composite exhibit excellent electrochemical properties. The Fe3O4/C composite electrode achieved a relatively high reversible specific capacity of 1450.1 mA h g-1 in the first cycle at 100 mA g-1, and excellent rate capability (69% retention at 1000 mA g-1) with good cycle stability (only 10% loss after 100 cycles).

Nonlinear pulse compression stage delivering 43-W few-cycle pulses with GW peak-power at 2-μm wavelength

NASA Astrophysics Data System (ADS)

Gebhardt, Martin; Gaida, Christian; Heuermann, T.; Stutzki, F.; Jauregui, C.; Antonio-Lopez, J.; Schüuzgen, A.; Amezcua-Correa, R.; Tünnermann, A.; Limpert, J.

2018-02-01

In this contribution we demonstrate the nonlinear pulse compression of an ultrafast thulium-doped fiber laser down to 14 fs FWHM duration (sub-3 optical cycles) at a record average power of 43 W and 34.5 μJ pulse energy. To the best of our knowledge, we present the highest average power few-cycle laser source at 2 μm wavelength. This performance level in combination with GW-class peak power makes our laser source extremely interesting for driving high-harmonic generation or for generating mid-infrared frequency combs via intra-pulse frequency down-conversion at an unprecedented average power. The experiments were enabled by an ultrafast thulium-doped fiber laser delivering 110 fs pulses at high repetition rates, and an argon gas-filled antiresonant hollow-core fiber (ARHCF) with excellent transmission and weak anomalous dispersion, leading to the self-compression of the pulses. We have shown that ARHCFs are well-suited for nonlinear pulse compression around 2 μm wavelength and that this concept features excellent power handling capabilities. Based on this result, we discuss the next steps for energy and average power scaling including upscaling the fiber dimensions in order to fully exploit the capabilities of our laser system, which can deliver several GW of peak power. This way, a 100 W-class laser source with mJ-level few-cycle pulses at 2 μm wavelength is feasible in the near future.

Toward Aerogel Electrodes of Superior Rate Performance in Supercapacitors through Engineered Hollow Nanoparticles of NiCo2O4.

PubMed

Li, Jianjiang; Chen, Shuai; Zhu, Xiaoyi; She, Xilin; Liu, Tongchao; Zhang, Huawei; Komarneni, Sridhar; Yang, Dongjiang; Yao, Xiangdong

2017-12-01

A biomass-templated pathway is developed for scalable synthesis of NiCo 2 O 4 @carbon aerogel electrodes for supercapacitors, where NiCo 2 O 4 hollow nanoparticles with an average outer diameter of 30-40 nm are conjoined by graphitic carbon forming a 3D aerogel structure. This kind of NiCo 2 O 4 aerogel structure shows large specific surface area (167.8 m 2 g -1 ), high specific capacitance (903.2 F g -1 at a current density of 1 A g -1 ), outstanding rate performance (96.2% capacity retention from 1 to 10 A g -1 ), and excellent cycling stability (nearly without capacitance loss after 3000 cycles at 10 A g -1 ). The unique structure of the 3D hollow aerogel synergistically contributes to the high performance. For instance, the 3D interconnected porous structure of the aerogel is beneficial for electrolyte ion diffusion and for shortening the electron transport pathways, and thus can improve the rate performance. The conductive carbon joint greatly enhances the specific capacity, and the hollow structure prohibits the volume changes during the charge-discharge process to significantly improve the cycling stability. This work represents a giant step toward the preparation of high-performance commercial supercapacitors.

Toward Aerogel Electrodes of Superior Rate Performance in Supercapacitors through Engineered Hollow Nanoparticles of NiCo2O4

PubMed Central

Li, Jianjiang; Chen, Shuai; Zhu, Xiaoyi; She, Xilin; Liu, Tongchao; Zhang, Huawei; Komarneni, Sridhar

2017-01-01

Abstract A biomass‐templated pathway is developed for scalable synthesis of NiCo2O4@carbon aerogel electrodes for supercapacitors, where NiCo2O4 hollow nanoparticles with an average outer diameter of 30–40 nm are conjoined by graphitic carbon forming a 3D aerogel structure. This kind of NiCo2O4 aerogel structure shows large specific surface area (167.8 m2 g−1), high specific capacitance (903.2 F g−1 at a current density of 1 A g−1), outstanding rate performance (96.2% capacity retention from 1 to 10 A g−1), and excellent cycling stability (nearly without capacitance loss after 3000 cycles at 10 A g−1). The unique structure of the 3D hollow aerogel synergistically contributes to the high performance. For instance, the 3D interconnected porous structure of the aerogel is beneficial for electrolyte ion diffusion and for shortening the electron transport pathways, and thus can improve the rate performance. The conductive carbon joint greatly enhances the specific capacity, and the hollow structure prohibits the volume changes during the charge–discharge process to significantly improve the cycling stability. This work represents a giant step toward the preparation of high‐performance commercial supercapacitors. PMID:29270344

A surfactant free preparation of ultradispersed surface-clean Pt catalyst with highly stable electrocatalytic performance

NASA Astrophysics Data System (ADS)

Tao, Lu; Zhao, Yueping; Zhao, Yufeng; Huang, Shifei; Yang, Yunxia; Tong, Qi; Gao, Faming

2018-02-01

High efficiency platinum-based catalyst demands the ultrafine size and well dispersion of Pt nanoparticles (NPs), with clean surface and strong interactions between the supports. In this work, we demonstrate a simple strategy for the preparation of ultra-dispersed surface-clean Pt catalyst with high stability, in which the Pt nanoparticles (NPs) with 1.8 ± 0.6 nm in size are anchored tightly on a 3D hierarchical porous graphitized carbon (3D-HPG) through galvanic replacement reaction. The as-obtained catalyst can undergo 2000 voltage cycles with negligible activity decay and no apparent structure and size changes for MOR during the durability test, and its mass activity for ORR only reduce 18.3% after 5000 cycles. The excellent performance is attributed to strong anchoring effect between carbon support and Pt nanoparticles.

Highly Stretchable Supercapacitors Based on Aligned Carbon Nanotube/Molybdenum Disulfide Composites.

PubMed

Lv, Tian; Yao, Yao; Li, Ning; Chen, Tao

2016-08-01

Stretchable supercapacitors that can sustain their performance under unpredictable tensile force are important elements for practical applications of various portable and wearable electronics. However, the stretchability of most reported supercapacitors was often lower than 100 % because of the limitation of the electrodes used. Herein we developed all-solid-state supercapacitors with a stretchability as high as 240 % by using aligned carbon nanotube composites with compact structure as electrodes. By combined with pseudocapacitive molybdenum disulfide nanosheets, the newly developed supercapacitor showed a specific capacitance of 13.16 F cm(-3) , and also showed excellent cycling retention (98 %) after 10 000 charge-discharge cycles. This work also presents a general and effective approach in developing high-performance electrodes for flexible and stretchable electronics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Copper Silicate Hydrate Hollow Spheres Constructed by Nanotubes Encapsulated in Reduced Graphene Oxide as Long-Life Lithium-Ion Battery Anode.

PubMed

Wei, Xiujuan; Tang, Chunjuan; Wang, Xuanpeng; Zhou, Liang; Wei, Qiulong; Yan, Mengyu; Sheng, Jinzhi; Hu, Ping; Wang, Bolun; Mai, Liqiang

2015-12-09

Hierarchical copper silicate hydrate hollow spheres-reduced graphene oxide (RGO) composite is successfully fabricated by a facile hydrothermal method using silica as in situ sacrificing template. The electrochemical performance of the composite as lithium-ion battery anode was studied for the first time. Benefiting from the synergistic effect of the hierarchical hollow structure and conductive RGO matrix, the composite exhibits excellent long-life performance and rate capability. A capacity of 890 mAh/g is achieved after 200 cycles at 200 mA/g and a capacity of 429 mAh/g is retained after 800 cycles at 1000 mA/g. The results indicate that the strategy of combining hierarchical hollow structures with conductive RGO holds the potential in addressing the volume expansion issue of high capacity anode materials.

An application of business process method to the clinical efficiency of hospital.

PubMed

Leu, Jun-Der; Huang, Yu-Tsung

2011-06-01

The concept of Total Quality Management (TQM) has come to be applied in healthcare over the last few years. The process management category in the Baldrige Health Care Criteria for Performance Excellence model is designed to evaluate the quality of medical services. However, a systematic approach for implementation support is necessary to achieve excellence in the healthcare business process. The Architecture of Integrated Information Systems (ARIS) is a business process architecture developed by IDS Scheer AG and has been applied in a variety of industrial application. It starts with a business strategy to identify the core and support processes, and encompasses the whole life-cycle range, from business process design to information system deployment, which is compatible with the concept of healthcare performance excellence criteria. In this research, we apply the basic ARIS framework to optimize the clinical processes of an emergency department in a mid-size hospital with 300 clinical beds while considering the characteristics of the healthcare organization. Implementation of the case is described, and 16 months of clinical data are then collected, which are used to study the performance and feasibility of the method. The experience gleaned in this case study can be used a reference for mid-size hospitals with similar business models.

US Federal LCA Commons Life Cycle Inventory Unit Process Template

EPA Science Inventory

The US Federal LCA Commons Life Cycle Inventory Unit Process Template is a multi-sheet Excel template for life cycle inventory data, metadata and other documentation. The template comes as a package that consistent of three parts: (1) the main template itself for life cycle inven...

Advanced Thermally Stable Coal-Based Jet Fuels

DTIC Science & Technology

2008-02-01

of hydrotreated refined chemical oil derived jet fuels in the pyrolytic regime. Preprints of Papers-American Chemical Society Division of Fuel...hydrogenation of a mixture of light cycle oil and refined chemical oil met or exceeded all but four JP-8 specifications. The fuel has excellent low-temperature...mixture of light cycle oil and refined chemical oil met or exceeded all but four JP-8 specifications. The fuel has excellent low-temperature viscosity

Architecturing hierarchical function layers on self-assembled viral templates as 3D nano-array electrodes for integrated Li-ion microbatteries.

PubMed

Liu, Yihang; Zhang, Wei; Zhu, Yujie; Luo, Yanting; Xu, Yunhua; Brown, Adam; Culver, James N; Lundgren, Cynthia A; Xu, Kang; Wang, Yuan; Wang, Chunsheng

2013-01-09

This work enables an elegant bottom-up solution to engineer 3D microbattery arrays as integral power sources for microelectronics. Thus, multilayers of functional materials were hierarchically architectured over tobacco mosaic virus (TMV) templates that were genetically modified to self-assemble in a vertical manner on current-collectors, so that optimum power and energy densities accompanied with excellent cycle-life could be achieved on a minimum footprint. The resultant microbattery based on self-aligned LiFePO(4) nanoforests of shell-core-shell structure, with precise arrangement of various auxiliary material layers including a central nanometric metal core as direct electronic pathway to current collector, delivers excellent energy density and stable cycling stability only rivaled by the best Li-ion batteries of conventional configurations, while providing rate performance per foot-print and on-site manufacturability unavailable from the latter. This approach could open a new avenue for microelectromechanical systems (MEMS) applications, which would significantly benefit from the concept that electrochemically active components be directly engineered and fabricated as an integral part of the integrated circuit (IC).

Polycarbonate-based polyurethane as a polymer electrolyte matrix for all-solid-state lithium batteries

NASA Astrophysics Data System (ADS)

Bao, Junjie; Shi, Gaojian; Tao, Can; Wang, Chao; Zhu, Chen; Cheng, Liang; Qian, Gang; Chen, Chunhua

2018-06-01

Four kinds of polycarbonate-based polyurethane with 8-14 wt% hard segments content are synthesized via reactions of polycarbonatediol, hexamethylene diisocyanate and diethylene glycol. The mechanical strength of the polyurethanes increase with the increase of hard segments content. Solid polymer electrolytes composed of the polycarbonate-based polyurethanes and LiTFSI exhibits fascinating characteristics for all-solid-state lithium batteries with a high ionic conductivity of 1.12 × 10-4 S cm-1 at 80 °C, an electrochemical stability window up to 4.5 V (vs. Li+/Li), excellent mechanical strength and superior interfacial stability against lithium metal. The all-solid-state batteries using LiFePO4 cathode can deliver high discharge capacities (161, 158, 134 and 93 mAh g-1 at varied rates of 0.2, 0.5, 1 and 2 C) at 80 °C and excellent cycling performance (with 91% capacity retention after 600 cycles at 1 C). All the results indicate that such a polyurethane-based solid polymer electrolyte can be a promising candidate for all-solid-state lithium batteries.

Porous graphitic carbon microtubes derived from willow catkins as a substrate of MnO2 for supercapacitors

NASA Astrophysics Data System (ADS)

Zhang, Xiaohua; Zhang, Kang; Li, Hengxiang; Cao, Qing; Jin, Li'e.; Li, Ping

2017-03-01

Biomass is receiving considerable attention because of its significant advantages as a sustainable and renewable material. Willow catkins, which have a single-walled microtubular structure are used as both a template and a precursor for synthesizing porous graphitic carbon microtubes (PGCMT) induced by the simultaneous activation-graphitization of K4Fe(CN)6. In addition to providing low-resistant pathways and short ion diffusion channels, as-obtained PGCMT with tubular structure also serves as an ideal platform for anchoring MnO2. The PGCMT/MnO2 composite electrode obtained by MnO2 electrodeposition expressed excellent electrochemical performance, including a significantly enhanced specific capacitance (550.8 F g-1 for the mass of MnO2 at a current density of 2 A g-1), a high capacitance retention of 61.8% even at a high current density of 50 A g-1, and an excellent cycling stability of 89.6% capability retention after 5000 cycles. These findings offer a simple and environmentally friendly strategy for preparing advanced energy materials by utilizing the unique structure of biomass waste from nature.

Synthesis of hierarchical porous δ-MnO2 nanoboxes as an efficient catalyst for rechargeable Li-O2 batteries

NASA Astrophysics Data System (ADS)

Zhang, Jian; Luan, Yanping; Lyu, Zhiyang; Wang, Liangjun; Xu, Leilei; Yuan, Kaidi; Pan, Feng; Lai, Min; Liu, Zhaolin; Chen, Wei

2015-09-01

A rechargeable lithium-oxygen (Li-O2) battery with a remarkably high theoretical energy storage capacity has attracted enormous research attention. However, the poor oxygen reduction and oxygen evolution reaction (ORR and OER) activities in discharge and charge processes cause low energy efficiency, poor electrolyte stability and short cycle life. This requires the development of efficient cathode catalysts to dramatically improve the Li-O2 battery performances. MnO2-based materials are recognized as efficient and low-cost catalysts for a Li-O2 battery cathode. Here, we report a controllable approach to synthesize hierarchical porous δ-MnO2 nanoboxes by using Prussian blue analogues as the precursors. The obtained products possess hierarchical pore size and an extremely large surface area (249.3 m2 g-1), which would favour oxygen transportation and provide more catalytically active sites to promote ORR and OER as the Li-O2 battery cathode. The battery shows enhanced discharge capacity (4368 mA h g-1@0.08 mA cm-2), reduced overpotential (270 mV), improved rate performance and excellent cycle stability (248 cycles@500 mA h g-1 and 112 cycles@1000 mA h g-1), in comparison with the battery with a VX-72 carbon cathode. The superb performance of the hierarchical porous δ-MnO2 nanoboxes, together with a convenient fabrication method, presents an alternative to develop advanced cathode catalysts for the Li-O2 battery.A rechargeable lithium-oxygen (Li-O2) battery with a remarkably high theoretical energy storage capacity has attracted enormous research attention. However, the poor oxygen reduction and oxygen evolution reaction (ORR and OER) activities in discharge and charge processes cause low energy efficiency, poor electrolyte stability and short cycle life. This requires the development of efficient cathode catalysts to dramatically improve the Li-O2 battery performances. MnO2-based materials are recognized as efficient and low-cost catalysts for a Li-O2 battery cathode. Here, we report a controllable approach to synthesize hierarchical porous δ-MnO2 nanoboxes by using Prussian blue analogues as the precursors. The obtained products possess hierarchical pore size and an extremely large surface area (249.3 m2 g-1), which would favour oxygen transportation and provide more catalytically active sites to promote ORR and OER as the Li-O2 battery cathode. The battery shows enhanced discharge capacity (4368 mA h g-1@0.08 mA cm-2), reduced overpotential (270 mV), improved rate performance and excellent cycle stability (248 cycles@500 mA h g-1 and 112 cycles@1000 mA h g-1), in comparison with the battery with a VX-72 carbon cathode. The superb performance of the hierarchical porous δ-MnO2 nanoboxes, together with a convenient fabrication method, presents an alternative to develop advanced cathode catalysts for the Li-O2 battery. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02983j

Center of Cancer Nanotechnology Excellence for Translational Diagnostics

Cancer.gov

The Center of Cancer Nanotechnology Excellence for Translational Diagnostics, which forms the third cycle CCNE Program at Stanford University, is a consortium that has three highly synchronized Projects and three Cores.

Improved lithium-ion battery anode capacity with a network of easily fabricated spindle-like carbon nanofibers.

PubMed

Liu, Mengting; Xie, Wenhe; Gu, Lili; Qin, Tianfeng; Hou, Xiaoyi; He, Deyan

2016-01-01

A novel network of spindle-like carbon nanofibers was fabricated via a simplified synthesis involving electrospinning followed by preoxidation in air and postcarbonization in Ar. Not only was the as-obtained carbon network comprised of beads of spindle-like nanofibers but the cubic MnO phase and N elements were successfully anchored into the amorphous carbon matrix. When directly used as a binder-free anode for lithium-ion batteries, the network showed excellent electrochemical performance with high capacity, good rate capacity and reliable cycling stability. Under a current density of 0.2 A g -1 , it delivered a high reversible capacity of 875.5 mAh g -1 after 200 cycles and 1005.5 mAh g -1 after 250 cycles with a significant coulombic efficiency of 99.5%.

Three-Dimensional Tubular MoS2/PANI Hybrid Electrode for High Rate Performance Supercapacitor.

PubMed

Ren, Lijun; Zhang, Gaini; Yan, Zhe; Kang, Liping; Xu, Hua; Shi, Feng; Lei, Zhibin; Liu, Zong-Huai

2015-12-30

By using three-dimensional (3D) tubular molybdenum disulfide (MoS2) as both an active material in electrochemical reaction and a framework to provide more paths for insertion and extraction of ions, PANI nanowire arrays with a diameter of 10-20 nm can be controllably grown on both the external and internal surface of 3D tubular MoS2 by in situ oxidative polymerization of aniline monomers and 3D tubular MoS2/PANI hybrid materials with different amounts of PANI are prepared. A controllable growth of PANI nanowire arrays on the tubular MoS2 surface provides an opportunity to optimize the capacitive performance of the obtained electrodes. When the loading amount of PANI is 60%, the obtained MoS2/PANI-60 hybrid electrode not only shows a high specific capacitance of 552 F/g at a current density of 0.5 A/g, but also gives excellent rate capability of 82% from 0.5 to 30 A/g. The remarkable rate performance can be mainly attributed to the architecture with synergistic effect between 3D tubular MoS2 and PANI nanowire arrays. Moreover, the MoS2/PANI-60 based symmetric supercapacitor also exhibits the excellent rate performance and good cycling stability. The specific capacitance based on the total mass of the two electrodes is 124 F/g at a current density of 1 A/g and 79% of its initial capacitance is remained after 6000 cycles. The 3D tubular structure provides a good and favorable method for improving the capacitance retention of PANI electrode.

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.

Preparation of 3D Architecture Graphdiyne Nanosheets for High-Performance Sodium-Ion Batteries and Capacitors.

PubMed

Wang, Kun; Wang, Ning; He, Jianjiang; Yang, Ze; Shen, Xiangyan; Huang, Changshui

2017-11-22

Here, we apply three-dimensional (3D) architecture graphdiyne nanosheet (GDY-NS) as anode materials for sodium-ion storage devices achieving high energy and power performance along with excellent cyclic ability. The contribution of 3D architecture nanostructure and intramolecular pores of the GDY-NS can substantially optimize the sodium storage behavior through the accommodated intramolecular pore, 3D interconnective porous structure, and increased activity sites to facilitate a fast sodium-ion-diffusion channel. The contribution of butadiyne linkages and the formation of a stable solid electrolyte interface layer are directly confirmed through the in situ Raman measurement. The GDY-NS-based sodium-ion batteries exhibit a stable reversible capacity of approximately 812 mAh g -1 at a current density of 0.05 A g -1 ; they maintain more than 405 mAh g -1 over 1000 cycles at a current density of 1 A g -1 . Furthermore, the sodium-ion capacitors could deliver a capacitance more than 200 F g -1 over 3000 cycles at 1 A g -1 and display an initial specific energy as high as 182.3 Wh kg -1 at a power density of 300 W kg -1 and maintain specific energy of 166 Wh kg -1 even at a power density of 15 000 W kg -1 . The high energy and power density along with excellent cyclic performance based on the GDY-NS anode offers a great potential toward application on next-generation energy storage devices.

Coupling Mo2C@C core-shell nanocrystals on 3D graphene hybrid aerogel for high-performance lithium ion battery

NASA Astrophysics Data System (ADS)

Xin, Hailin; Hai, Yang; Li, Dongzhi; Qiu, Zhaozheng; Lin, Yemao; Yang, Bo; Fan, Haosen; Zhu, Caizhen

2018-05-01

Hybrid aerogel by dispersing Mo2C@C core-shell nanocrystals into three-dimensional (3D) graphene (Mo2C@C-GA) has been successfully prepared through two-step methods. Firstly, carbon-coated MoO2 nanocrystals uniformly anchor on 3D graphene aerogel (MoO2@C-GA) via hydrothermal reaction. Then the MoO2@C-GA precursor is transformed into Mo2C@C-GA after the following carbonization process. Furthermore, the freeze-drying step plays an important role in the resulting pore size distribution of the porous networks. Moreover, graphene aerogels exhibit extremely low densities and superior electrical properties. When evaluated as anode material for lithium ion battery, Mo2C@C-GA delivers excellent rate capability and stable cycle performance when compared with C-GA and Mo2C nanoparticles. Mo2C@C-GA exhibits the initial discharge capacity of 1461.4 mA h g-1 at the current density of 0.1 A g-1, and retains a reversible capacity of 1089.8 mA h g-1 after 100 cycles at a current density of 0.1 A g-1. Even at high current density of 5 A g-1, a discharge capacity of 623.5 mA h g-1 can be still achieved. The excellent performance of Mo2C@C-GA could be attributed to the synergistic effect of Mo2C@C nanocrystals and the 3D graphene conductive network.

In-situ growth of MnO2 crystals under nanopore-constraint in carbon nanofibers and their electrochemical performance

PubMed Central

Le, TrungHieu; Yang, Ying; Yu, Liu; Huang, Zheng-hong; Kang, Feiyu

2016-01-01

Growing MnO2 nanocrystals in the bulk of porous carbon nanofibers is conducted in a KMnO4 aqueous solution aimed to enhance the electrochemical performance of MnO2. The rate of redox reaction between KMnO4 and carbon was controlled by the concentration of KMnO4 in a neutral solution. The MnO2 nanoparticles grow along with (211) crystal faces when the redox reaction happens on the surface of fibers under 1D constraint, while the nanoparticles grow along with (200) crystal faces when the redox reaction happens in the bulk of fibers under 3D constraint. The composite, where MnO2 nanoparticles are formed in the bulk under a constraint, yields an electrode material for supercapacitors showing good electron transport, rapid ion penetration, fast and reversible Faradaic reaction, and excellent rate performance. The capacitance of the composite electrode could be 1282 F g−1 under a current density of 0.2 A g−1 in 1 M Na2SO4 electrolyte. A symmetric supercapacitor delivers energy density of 36 Wh kg−1 with power density of 39 W kg−1, and can maintain 7.5 Wh kg−1 at 10.3 kW kg−1. It exhibits an excellent electrochemical cycling stability with 101% initial capacitance and 95% columbic efficiency even after 1000 cycles of charge/discharge. PMID:27869184

Facile synthesis of NiS anchored carbon nanofibers for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Xu, Jinling; Zhang, Li; Xu, Guancheng; Sun, Zhipeng; Zhang, Chi; Ma, Xin; Qi, Chunling; Zhang, Lu; Jia, Dianzeng

2018-03-01

Transition metal sulfide compounds with carbon materials are promising for high-performance supercapacitors. Carbon nanofibers (CNFs) wrapped with NiS nanoparticles were herein obtained through electrospinning and calcination. NiS nanoparticles in composite nanofibers are covered by a layer of graphitic carbon, which not only increase the conductivity but also provide active regions for nanoparticle growth to prevent aggregation. The CNFs-NiS electrode has high specific capacity of 177.1 mAh g-1 at 1 A g-1 (0.41 mAh cm-2 at a current density of 2.3 mA cm-2) and long-term cycling stability, with 88.7% capacitance retention after 5000 cycles. The excellent electrochemical activity may be attributed to the accessible specific surface, unique porous structure of CNFs and high specific capacitance of NiS. In addition, the asymmetric supercapacitor has an enhanced volumetric energy density of 13.32 mWh cm-3 at a volumetric power density of 180 mW cm-3 and high cycling stability, with 89.5% capacitance retention after 5000 cycles. It also successfully lights up a light-emitting diode. The CNFs-NiS composite has significant potential applications in supercapacitor.

Electrochemically fabricated polypyrrole-cobalt-oxygen coordination complex as high-performance lithium-storage materials.

PubMed

Guo, Bingkun; Kong, Qingyu; Zhu, Ying; Mao, Ya; Wang, Zhaoxiang; Wan, Meixiang; Chen, Liquan

2011-12-23

Current lithium-ion battery (LIB) technologies are all based on inorganic electrode materials, though organic materials have been used as electrodes for years. Disadvantages such as limited thermal stability and low specific capacity hinder their applications. On the other hand, the transition metal oxides that provide high lithium-storage capacity by way of electrochemical conversion reaction suffer from poor cycling stability. Here we report a novel high-performance, organic, lithium-storage material, a polypyrrole-cobalt-oxygen (PPy-Co-O) coordination complex, with high lithium-storage capacity and excellent cycling stability. Extended X-ray absorption fine structure and Raman spectroscopy and other physical and electrochemical characterizations demonstrate that this coordination complex can be electrochemically fabricated by cycling PPy-coated Co(3)O(4) between 0.0 V and 3.0 V versus Li(+)/Li. Density functional theory (DFT) calculations indicate that each cobalt atom coordinates with two nitrogen atoms within the PPy-Co coordination layer and the layers are connected with oxygen atoms between them. Coordination weakens the C-H bonds on PPy and makes the complex a novel lithium-storage material with high capacity and high cycling stability. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Small quaternary alkyl phosphonium bis(fluorosulfonyl)imide ionic liquid electrolytes for sodium-ion batteries with P2- and O3-Na2/3[Fe2/3Mn1/3]O2 cathode material

NASA Astrophysics Data System (ADS)

Hilder, Matthias; Howlett, Patrick C.; Saurel, Damien; Gonzalo, Elena; Armand, Michel; Rojo, Teófilo; Macfarlane, Douglas R.; Forsyth, Maria

2017-05-01

A saturated solution of 2.3 M sodium bis(fluorosulfonyl)imide in trimethyl iso-butyl phosphonium bis(fluorosulfonyl)imide ionic liquid shows a high conductivity (0.94 mScm-1 at 50 °C), low ion association, and a wide operational temperature window (-71 °C-305 °C) making it a promising electrolyte for sodium battery applications. Cycling with P2- and O3-Na2/3[Fe2/3Mn1/3]O2 cathode display excellent performance at 50 °C outperforming conventional organic solvent based electrolytes in terms of capacities (at C/10) and long term cycle stability (at C/2). Post analysis of the electrolyte shows no measurable changes while the sodium metal anode and the cathode surface shows the presence of electrolyte specific elements after cycling, suggesting the formation of a stabilizing solid electrolyte interface. Additionally, cycling changes the topography and particle morphology of the cathode. Thus, the electrolyte properties and cell performance match or outperform previously reported results with the additional benefit of replacing the hazardous and flammable organic solvent solutions commonly employed.

Large and stable reversible lithium-ion storages from mesoporous SnO2 nanosheets with ultralong lifespan over 1000 cycles

NASA Astrophysics Data System (ADS)

Zhang, Xiao; Jiang, Bin; Guo, Jinxue; Xie, Yaping; Tang, Lin

2014-12-01

The major challenge to promote the commercialization of SnO2 anode materials is to construct unique structures and/or composites that could alleviate the volume effect and extend the lifespan. This study develops an efficient synthetic solution for the preparation of mesoporous SnO2 nanosheets, which involves an evaporation-induced selfassembly process and the following thermal treatment. Surfactant F127 is used as the soft template to form abundant cores. The as-prepared sample intrinsically inherits flexible sheet-like structure and porous features, as characterized with XRD, SEM, TEM and BET techniques. Based on these combining structural benefits, the sample is utilized as anode materials for lithium-ion batteries and exhibits excellent Li+ storage performance such as large and stable reversible capacity, good rate capability, and especially the outstanding durable cycling life of over 1000 cycles, which meets the demands of practical applications. The structural changes of SnO2 nanosheets are observed from the decomposed electrodes after different electrochemical cycles. Moreover, this synthesis strategy may offer an alternative and universal approach for synthesis of other transitional metal oxides or their binary composites as high-performance anode materials for lithium-ion batteries.

Evolution of Reduced Graphene Oxide-SnS2 Hybrid Nanoparticle Electrodes in Li-Ion Batteries.

PubMed

Modarres, Mohammad H; Lim, Jonathan Hua-Wei; George, Chandramohan; De Volder, Michael

2017-06-22

Hybrid nanomaterials where active battery nanoparticles are synthesized directly onto conductive additives such as graphene hold the promise of improving the cyclability and energy density of conversion and alloying type Li-ion battery electrodes. Here we investigate the evolution of hybrid reduced graphene oxide-tin sulfide (rGO-SnS 2 ) electrodes during battery cycling. These hybrid nanoparticles are synthesized by a one-step solvothermal microwave reaction which allows for simultaneous synthesis of the SnS 2 nanocrystals and reduction of GO. Despite the hybrid architecture of these electrodes, electrochemical impedance spectroscopy shows that the impedance doubles in about 25 cycles and subsequently gradually increases, which may be caused by an irreversible surface passivation of rGO by sulfur enriched conversion products. This surface passivation is further confirmed by post-mortem Raman spectroscopy of the electrodes, which no longer detects rGO peaks after 100 cycles. Moreover, galvanostatic intermittent titration analysis during the 1st and 100th cycles shows a drop in Li-ion diffusion coefficient of over an order of magnitude. Despite reports of excellent cycling performance of hybrid nanomaterials, our work indicates that in certain electrode systems, it is still critical to further address passivation and charge transport issues between the active phase and the conductive additive in order to retain high energy density and cycling performance.

Evolution of Reduced Graphene Oxide–SnS2 Hybrid Nanoparticle Electrodes in Li-Ion Batteries

PubMed Central

2017-01-01

Hybrid nanomaterials where active battery nanoparticles are synthesized directly onto conductive additives such as graphene hold the promise of improving the cyclability and energy density of conversion and alloying type Li-ion battery electrodes. Here we investigate the evolution of hybrid reduced graphene oxide–tin sulfide (rGO-SnS2) electrodes during battery cycling. These hybrid nanoparticles are synthesized by a one-step solvothermal microwave reaction which allows for simultaneous synthesis of the SnS2 nanocrystals and reduction of GO. Despite the hybrid architecture of these electrodes, electrochemical impedance spectroscopy shows that the impedance doubles in about 25 cycles and subsequently gradually increases, which may be caused by an irreversible surface passivation of rGO by sulfur enriched conversion products. This surface passivation is further confirmed by post-mortem Raman spectroscopy of the electrodes, which no longer detects rGO peaks after 100 cycles. Moreover, galvanostatic intermittent titration analysis during the 1st and 100th cycles shows a drop in Li-ion diffusion coefficient of over an order of magnitude. Despite reports of excellent cycling performance of hybrid nanomaterials, our work indicates that in certain electrode systems, it is still critical to further address passivation and charge transport issues between the active phase and the conductive additive in order to retain high energy density and cycling performance. PMID:28804530

The electrochemical exploration of double carbon-wrapped Na3V2(PO4)3: Towards long-time cycling and superior rate sodium-ion battery cathode

NASA Astrophysics Data System (ADS)

Li, Sijie; Ge, Peng; Zhang, Chenyang; Sun, Wei; Hou, Hongshuai; Ji, Xiaobo

2017-10-01

Na3V2(PO4)3 (NVP) is a very promising cathode material in sodium ion battery for rapidly emerging large-scale energy storage with its classical 3D NASCION structure. However, the cycling life and rate performances are restricted its low electronic conductivity. To overcome these, the double carbon-wrapped Na3V2(PO4)3 composite is firstly designed through rheological phase approach, delivering enhanced electrochemical properties. The unique double carbon layers are composed of uniform amorphous carbons as protecting framework for stabilizing the structure, as well as the graphitized carbon sheets playing the role of conductive network for better electronic conductivity. This double carbon-wrapped Na3V2(PO4)3 composite exhibits a high reversible capacity of 99.8 mAh g-1 over 500 cycles at 1 C (110 mA g-1), yielding the coulombic efficiency of ∼99.8%. Meanwhile, it displays an initial capacity of 73 mAh g-1 at 100 C and remains 55 mAh g-1 at an ultra-rate of 200 C. Even after cycling at 200 C over 12 000 cycles, the Na+-storage capacity of 40 mAh g-1 with a retention of 72.7% is still obtained, highlighting its excellent long cycling life and remarkable rate performances.

Graphene Oxides Used as a New "Dual Role" Binder for Stabilizing Silicon Nanoparticles in Lithium-Ion Battery.

PubMed

Shan, Changsheng; Wu, Kaifeng; Yen, Hung-Ju; Narvaez Villarrubia, Claudia; Nakotte, Tom; Bo, Xiangjie; Zhou, Ming; Wu, Gang; Wang, Hsing-Lin

2018-05-09

For the first time, we report that graphene oxide (GO) can be used as a new "dual-role" binder for Si nanoparticles (SiNPs)-based lithium-ion batteries (LIBs). GO not only provides a graphene-like porous 3D framework for accommodating the volume changes of SiNPs during charging/discharging cycles, but also acts as a polymer-like binder that forms strong chemical bonds with SiNPs through its Si-OH functional groups to trap and stabilize SiNPs inside the electrode. Leveraging this unique dual-role of GO binder, we fabricated GO/SiNPs electrodes with remarkably improved performances as compared to using the conventional polyvinylidene fluoride (PVDF) binder. Specifically, the GO/SiNPs electrode showed a specific capacity of 2400 mA h g -1 at the 50th cycle and 2000 mA h g -1 at the 100th cycle, whereas the SiNPs/PVDF electrode only showed 456 mAh g -1 at the 50th cycle and 100 mAh g -1 at 100th cycle. Moreover, the GO/SiNPs film maintained its structural integrity and formed a stable solid-electrolyte interphase (SEI) film after 100 cycles. These results, combined with the well-established facile synthesis of GO, indicate that GO can be an excellent binder for developing high performance Si-based LIBs.

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

Solar Spectral Irradiance Variability in Cycle 24: Model Predictions and OMI Observations

NASA Technical Reports Server (NTRS)

Marchenko, S.; DeLand, M.; Lean, J.

2016-01-01

Utilizing the excellent stability of the Ozone Monitoring Instrument (OMI), we characterize both short-term (solar rotation) and long-term (solar cycle) changes of the solar spectral irradiance (SSI) between 265-500 nanometers during the ongoing Cycle 24. We supplement the OMI data with concurrent observations from the GOME-2 (Global Ozone Monitoring Experiment - 2) and SORCE (Solar Radiation and Climate Experiment) instruments and find fair-to-excellent agreement between the observations and predictions of the NRLSSI2 (Naval Research Laboratory Solar Spectral Irradiance - post SORCE) and SATIRE-S (the Naval Research Laboratory's Spectral And Total Irradiance REconstruction for the Satellite era) models.

Effect of combinations of additives on the performance of lithium ion batteries

NASA Astrophysics Data System (ADS)

Santee, Stuart; Xiao, Ang; Yang, Li; Gnanaraj, Joe; Lucht, Brett L.

Commercial lithium-ion batteries have excellent performance at room temperature for a few years. However, the calendar life and thermal stability (>50 °C) need to be improved for many applications, including electric vehicles. We have conducted an investigation of the effect of thermal stabilizing additives, including dimethyl acetamide, vinylene carbonate, and lithium bis(oxalato) borate, on the performance of lithium ion batteries stored at 70 °C for one month. The reactions of the lithium hexafluorophosphate/carbonate electrolyte, with and without electrolyte additives, with the surface of the electrodes after initial formation cycling have been analyzed via a combination of IR-ATR and XPS.

High-performance transparent and stretchable all-solid supercapacitors based on highly aligned carbon nanotube sheets

PubMed Central

Chen, Tao; Peng, Huisheng; Durstock, Michael; Dai, Liming

2014-01-01

By using highly aligned carbon nanotube (CNT) sheets of excellent optical transmittance and mechanical stretchability as both the current collector and active electrode, high-performance transparent and stretchable all-solid supercapacitors with a good stability were developed. A transmittance up to 75% at the wavelength of 550 nm was achieved for a supercapacitor made from a cross-over assembly of two single-layer CNT sheets. The transparent supercapacitor has a specific capacitance of 7.3 F g−1 and can be biaxially stretched up to 30% strain without any obvious change in electrochemical performance even over hundreds stretching cycles. PMID:24402400

Ultrasmall TiO2-Coated Reduced Graphene Oxide Composite as a High-Rate and Long-Cycle-Life Anode Material for Sodium-Ion Batteries.

PubMed

Liu, Yao; Liu, Jingyuan; Bin, Duan; Hou, Mengyan; Tamirat, Andebet Gedamu; Wang, Yonggang; Xia, Yongyao

2018-05-02

Because of the low cost and abundant nature of the sodium element, sodium-ion batteries (SIBs) are attracting extensive attention, and a variety of SIB cathode materials have been discovered. However, the lack of high-performance anode materials is a major challenge of SIBs. Herein, we have synthesized ultrasmall TiO 2 -nanoparticle-coated reduced graphene oxide (TiO 2 @RGO) composites by using a one-pot hydrolysis method, which are then investigated as anode materials for SIBs. The morphology of TiO 2 @RGO has been characterized using transmission electron microscopy, indicating that the TiO 2 nanospheres uniformly grow on the surface of the RGO nanosheet. As-prepared TiO 2 @RGO composites exhibited a promising electrochemical performance in terms of cycling stability and rate capability, especially the initial cycle Coulombic efficiency of 60.7%, which is higher than that in previous reports. The kinetics of the electrode reaction has been investigated by cyclic voltammetry. The results indicate that the sodium-ion intercalation/extraction behavior is not controlled by the semiinfinite diffusion process, which gives rise to an outstanding rate performance. In addition, the electrochemical performance of TiO 2 @RGO composites in full cells, coupled with carbon-coated Na 3 V 2 (PO 4 ) 3 as the positive material, has been investigated. The discharge specific capacity was up to 117.2 mAh g -1 , and it remained at 84.6 mAh g -1 after 500 cycles under a current density of 2 A g -1 , which shows excellent cycling stability.

Exploring aligned-carbon-nanotubes@polyaniline arrays on household Al as supercapacitors.

PubMed

Huang, Fan; Lou, Fengliu; Chen, De

2012-05-01

Herein, we demonstrate a new approach towards the construction of supercapacitors consisting of carbon nanotubes (CNTs) and conducting polymers (ECPs) with high specific power, high specific energy, and stable cycling performance through a 3D design of a thin film of polyaniline (PANI) on an aligned small carbon nanotube (ACNT) array on household Al foils. The thin-film strategy is used to fully exploit the specific capacitance of PANI, and obtain regular pores, strong interaction between PANI and CNTs, and reduced electrical resistance for the electrodes. A facile process is developed to fabricate a highly flexible supercapacitor using this binder-free composite on household Al foil as the current collector. It exhibits high specific energy of 18.9 Wh kg(-1) , high maximum specific power of 11.3 kW kg(-1) of the active material in an aqueous electrolyte at 1.0 A g(-1) , and excellent rate performance and cycling stability. A high specific energy of 72.4 Wh kg(-1) , a high maximum specific power of 24.9 kW kg(-1) , and a good cycling performance of the active material are obtained in an organic electrolyte. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lightweight Reduced Graphene Oxide@MoS2 Interlayer as Polysulfide Barrier for High-Performance Lithium-Sulfur Batteries.

PubMed

Tan, Lei; Li, Xinhai; Wang, Zhixing; Guo, Huajun; Wang, Jiexi

2018-01-31

The further development of lithium-sulfur (Li-S) batteries is limited by the fact that the soluble polysulfide leads to the shuttle effect, thereby reducing the cycle stability and cycle life of the batteries. To address this issue, here a thin and lightweight (8 μm and 0.24 mg cm -2 ) reduced graphene oxide@MoS 2 (rGO@MoS 2 ) interlayer between the cathode and the commercial separator is developed as a polysulfide barrier. The rGO plays the roles of both a polysulfide physical barrier and an additional current collector, while MoS 2 has a high chemical adsorption for polysulfides. The experiments demonstrate that the Li-S cell constructed with an rGO@MoS 2 -coated separator shows a high reversible capacity of 1122 mAh g -1 at 0.2 C, a low capacity fading rate of 0.116% for 500 cycles at 1 C, and an outstanding rate performance (615 mAh g -1 at 2 C). Such an interlayer is expected to be ideal for lithium-sulfur battery applications because of its excellent electrochemical performance and simple synthesis process.

Hard Carbon Originated from Polyvinyl Chloride Nanofibers As High-Performance Anode Material for Na-Ion Battery

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

Bai, Ying; Wang, Zhen; Wu, Chuan

2015-02-27

Two types of hard carbon materials were synthesized through direct pyrolysis of commercial polyvinyl chloride (PVC) particles and pyrolysis of PVC nanofibers at 600-800 degrees C, respectively, where the nanofibers were prepared by an electrospinning PVC precursors method. These as-prepared hard carbon samples were used as anode materials for Na-ion batteries. The hard carbon obtained from PVC nanofibers achieved a high reversible capacity of 271 mAh/g and an initial Coulombic efficiency of 69.9%, which were much superior to the one from commercial PVC, namely, a reversible capacity of 206 mAh/g and an initial Coulombic efficiency of 60.9%. In addition, themore » hard carbon originated from the PVC nanofibers exhibited good cycling stability and rate performance: the initial discharge capacities were 389, 228, 194, 178, 147 mAh/g at the current density of 12, 24, 60, 120, and 240 mA/g, respectively, retaining 211 mAh/g after 150 cycles. Such excellent cycle performance, high reversible capacity, and good rate capability enabled this hard carbon to be a promising candidate as anode material for Na-ion battery application.« less

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.

Hard carbon originated from polyvinyl chloride nanofibers as high-performance anode material for Na-ion battery.

PubMed

Bai, Ying; Wang, Zhen; Wu, Chuan; Xu, Rui; Wu, Feng; Liu, Yuanchang; Li, Hui; Li, Yu; Lu, Jun; Amine, Khalil

2015-03-11

Two types of hard carbon materials were synthesized through direct pyrolysis of commercial polyvinyl chloride (PVC) particles and pyrolysis of PVC nanofibers at 600-800 °C, respectively, where the nanofibers were prepared by an electrospinning PVC precursors method. These as-prepared hard carbon samples were used as anode materials for Na-ion batteries. The hard carbon obtained from PVC nanofibers achieved a high reversible capacity of 271 mAh/g and an initial Coulombic efficiency of 69.9%, which were much superior to the one from commercial PVC, namely, a reversible capacity of 206 mAh/g and an initial Coulombic efficiency of 60.9%. In addition, the hard carbon originated from the PVC nanofibers exhibited good cycling stability and rate performance: the initial discharge capacities were 389, 228, 194, 178, 147 mAh/g at the current density of 12, 24, 60, 120, and 240 mA/g, respectively, retaining 211 mAh/g after 150 cycles. Such excellent cycle performance, high reversible capacity, and good rate capability enabled this hard carbon to be a promising candidate as anode material for Na-ion battery application.

Design of high-performance cathode materials with single-phase pathway for sodium ion batteries: A study on P2-Nax(LiyMn1-y)O2 compounds

NASA Astrophysics Data System (ADS)

Yang, Lufeng; Li, Xiang; Ma, Xuetian; Xiong, Shan; Liu, Pan; Tang, Yuanzhi; Cheng, Shuang; Hu, Yan-Yan; Liu, Meilin; Chen, Hailong

2018-03-01

Sodium-ion batteries (SIBs) are an emerging electrochemical energy storage technology that has high promise for electrical grid level energy storage. High capacity, long cycle life, and low cost cathode materials are very much desired for the development of high performance SIB systems. Sodium manganese oxides with different compositions and crystal structures have attracted much attention because of their high capacity and low cost. Here we report our investigations into a group of promising lithium doped sodium manganese oxide cathode materials with exceptionally high initial capacity of ∼223 mAh g-1 and excellent capacity retentions, attributed primarily to the absence of phase transformation in a wide potential range of electrochemical cycling, as confirmed by in-operando X-ray diffraction (XRD), Rietveld refinement, and high-resolution 7Li solid-state NMR characterizations. The systematic study of structural evolution and the correlation with the electrochemical behavior of the doped cathode materials provides new insights into rational design of high-performance intercalation compounds by tailoring the composition and the crystal structure evolution in electrochemical cycling.

Porous NiCo2O4 nanosheets/reduced graphene oxide composite: facile synthesis and excellent capacitive performance for supercapacitors.

PubMed

Ma, Lianbo; Shen, Xiaoping; Ji, Zhenyuan; Cai, Xiaoqing; Zhu, Guoxing; Chen, Kangmin

2015-02-15

A composite with porous NiCo2O4 nanosheets attached on reduced graphene oxide (RGO) sheets is synthesized through a facile solution-based method combined with a simple thermal annealing process. The capacitive performances of the as-prepared NiCo2O4/RGO (NCG) composites as electrode materials are investigated. It is found that the NCG composites exhibit a high specific capacitance up to 1186.3 F g(-1) at the current density of 0.5 A g(-1), and superior cycling stability with about 97% of the initial capacitance after 100 cycles. The greatly enhanced capacitive performance of the NCG electrode can be attributed to the existence of RGO support, which serves as both conductive channels and active interface. The approach used in the synthesis provides a facile route for preparing graphene-binary metal oxide electrode materials. The remarkable capacitive performance of NCG composites will undoubtedly make them be attractive for high performance energy storage applications. Copyright © 2014 Elsevier Inc. All rights reserved.

High-energy asymmetric supercapacitors based on free-standing hierarchical Co-Mo-S nanosheets with enhanced cycling stability.

PubMed

Balamurugan, Jayaraman; Li, Chao; Peera, Shaik Gouse; Kim, Nam Hoon; Lee, Joong Hee

2017-09-21

Layered transition metal sulfides (TMS) are emerging as advanced materials for energy storage and conversion applications. In this work, we report a facile and cost-effective anion exchange technique to fabricate a layered, multifaceted, free standing, ultra-thin ternary cobalt molybdenum sulfide nanosheet (Co-Mo-S NS) architecture grown on a 3D porous Ni foam substrate. The unique Co-Mo layered double hydroxides are first synthesized as precursors and consequently transformed into ultra-thin Co-Mo-S NS. When employed as an electrode for supercapacitors, the Co-Mo-S NS delivered an ultra-high specific capacitance of 2343 F g -1 at a current density of 1 mA cm -2 with tremendous rate capability and extraordinary cycling performance (96.6% capacitance retention after 20 000 cycles). Furthermore, assembled Co-Mo-S/nitrogen doped graphene nanosheets (NGNS) in an asymmetric supercapacitor (ASC) device delivered an excellent energy density of 89.6 Wh kg -1 , an amazing power density of 20.07 kW kg -1 , and superior cycling performance (86.8% capacitance retention after 50 000 cycles). Such exceptional electrochemical performance of Co-Mo-S NS is ascribed to the good electrical contact with the 3D Ni foam, ultra-high contact area with the electrolyte, and enhanced architectural softening during the charging/discharging process. It is expected that the fabricated, unique, ultra-thin Co-Mo-S NS have great potential for future energy storage devices.

Si Nanocrystal-Embedded SiO x nanofoils: Two-Dimensional Nanotechnology-Enabled High Performance Li Storage Materials.

PubMed

Yoo, Hyundong; Park, Eunjun; Bae, Juhye; Lee, Jaewoo; Chung, Dong Jae; Jo, Yong Nam; Park, Min-Sik; Kim, Jung Ho; Dou, Shi Xue; Kim, Young-Jun; Kim, Hansu

2018-05-02

Silicon (Si) based materials are highly desirable to replace currently used graphite anode for lithium ion batteries. Nevertheless, its usage is still a big challenge due to poor battery performance and scale-up issue. In addition, two-dimensional (2D) architectures, which remain unresolved so far, would give them more interesting and unexpected properties. Herein, we report a facile, cost-effective, and scalable approach to synthesize Si nanocrystals embedded 2D SiO x nanofoils for next-generation lithium ion batteries through a solution-evaporation-induced interfacial sol-gel reaction of hydrogen silsesquioxane (HSiO 1.5 , HSQ). The unique nature of the thus-prepared centimeter scale 2D nanofoil with a large surface area enables ultrafast Li + insertion and extraction, with a reversible capacity of more than 650 mAh g -1 , even at a high current density of 50 C (50 A g -1 ). Moreover, the 2D nanostructured Si/SiO x nanofoils show excellent cycling performance up to 200 cycles and maintain their initial dimensional stability. This superior performance stems from the peculiar nanoarchitecture of 2D Si/SiO x nanofoils, which provides short diffusion paths for lithium ions and abundant free space to effectively accommodate the huge volume changes of Si during cycling.

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

Performance and Durability of High Temperature Foil Air Bearings for Oil-Free Turbomachinery

NASA Technical Reports Server (NTRS)

DellaCorte, C.; Lukaszewicz, V.; Valco, M. J.; Radil, K. C.; Heshmat, H.

2000-01-01

The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS304, is applied to the shaft by plasma spraying. PS304 is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS304 coating are well suited for advanced high temperature, oil-free turbomachinery applications.

Nitrogen-doped mesoporous carbons for high performance supercapacitors

NASA Astrophysics Data System (ADS)

Wu, Kai; Liu, Qiming

2016-08-01

The mesoporous carbons have been synthesized by using α-D(+)-Glucose, D-Glucosamine hydrochloride or their mixture as carbon precursors and mesoporous silicas (SBA-15 or MCF) as hard templates. The as-prepared products show a large pore volume (0.59-0.97 cm3 g-1), high surface areas (352.72-1152.67 m2 g-1) and rational nitrogen content (ca. 2.5-3.9 wt.%). The results of electrochemical tests demonstrate that both heteroatom doping and suitable pore structure play a decisive role in the performance of supercapacitors. The representative sample of SBA-15 replica obtained using D-Glucosamine hydrochloride only exhibits high specific capacitance (212.8 F g-1 at 0.5 A g-1) and good cycle durability (86.1% of the initial capacitance after 2000 cycles) in 6 M KOH aqueous electrolyte, which is attributed to the contribution of double layer capacitance and pseudo-capacitance. The excellent electrochemical performance makes it a promising electrode material for supercapacitors.

Effect of Nickel Coated Multi-Walled Carbon Nanotubes on Electrochemical Performance of Lithium-Sulfur Rechargeable Batteries.

PubMed

Wu, Xiao; Yao, Shanshan; Hou, Jinli; Jing, Maoxiang; Qian, Xinye; Shen, Xiangqian; Xiang, Jun; Xi, Xiaoming

2017-04-01

Conventional lithium-sulfur batteries suffer from severe capacity fade, which is induced by low electron conductivity and high dissolution of intermediated polysulfides. Recent studies have shown the metal (Pt, Au, Ni) as electrocatalyst of lithium polysulfides and improved the performance for lithium sulfur batteries. In this work, we present the nickel coated multi-walled carbon nanotubes (Ni-MWNTs) as additive materials for elemental sulfur positive electrodes for lithium-sulfur rechargeable batteries. Compared with MWNTs, the obtained Ni-MWNTs/sulfur composite cathode demonstrate a reversible specific capacity approaching 545 mAh after 200 cycles at a rate of 0.5C as well as improved cycling stability and excellent rate capacity. The improved electrochemical performance can be attributed to the fact the MWNTs shows a vital role on polysulfides adsorption and nickel has a catalytic effect on the redox reactions during charge–discharge process. Meanwhile, the Ni-MWNTs is a good electric conductor for sulfur cathode.

Ternary manganese ferrite/graphene/polyaniline nanostructure with enhanced electrochemical capacitance performance

NASA Astrophysics Data System (ADS)

Xiong, Pan; Hu, Chenyao; Fan, Ye; Zhang, Wenyao; Zhu, Junwu; Wang, Xin

2014-11-01

A ternary manganese ferrite/graphene/polyaniline (MGP) nanostructure is designed and synthesized via a facile two-step approach. This nanostructure exhibits outstanding electrochemical performances, such as high specific capacitance (454.8 F g-1 at 0.2 A g-1), excellent rate capability (75.8% capacity retention at 5 A g-1), and good cycling stability (76.4% capacity retention after 5000 cycles at 2 A g-1), which are superior to those of its individual components (manganese ferrite, reduced-graphene oxide, polyaniline) and corresponding binary hybrids (manganese ferrite/graphene (MG), manganese ferrite/polyaniline (MP), and graphene/polyaniline (GP)). A symmetric supercapacitor device using the as-obtained hybrid has been fabricated and tested. The device exhibits a high specific capacitance of 307.2 F g-1 at 0.1 A g-1 with a maximum energy density of 13.5 W h kg-1. The high electrochemical performance of ternary MGP can be attributed to its well-designed nanostructure and the synergistic effect of the individual components.

Evaluation of fluorophores for optimal performance in localization-based super-resolution imaging

PubMed Central

Dempsey, Graham T.; Vaughan, Joshua C.; Chen, Kok Hao; Bates, Mark; Zhuang, Xiaowei

2011-01-01

One approach to super-resolution fluorescence imaging uses sequential activation and localization of individual fluorophores to achieve high spatial resolution. Essential to this technique is the choice of fluorescent probes — the properties of the probes, including photons per switching event, on/off duty cycle, photostability, and number of switching cycles, largely dictate the quality of super-resolution images. While many probes have been reported, a systematic characterization of the properties of these probes and their impact on super-resolution image quality has been described in only a few cases. Here, we quantitatively characterized the switching properties of 26 organic dyes and directly related these properties to the quality of super-resolution images. This analysis provides a set of guidelines for characterization of super-resolution probes and a resource for selecting probes based on performance. Our evaluation identified several photoswitchable dyes with good to excellent performance in four independent spectral ranges, with which we demonstrated low crosstalk, four-color super-resolution imaging. PMID:22056676

Realization of Both High-Performance and Enhanced Durability of Fuel Cells: Pt-Exoskeleton Structure Electrocatalysts.

PubMed

Kim, Ok-Hee; Cho, Yoon-Hwan; Jeon, Tae-Yeol; Kim, Jung Won; Cho, Yong-Hun; Sung, Yung-Eun

2015-07-01

Core-shell structure nanoparticles have been the subject of many studies over the past few years and continue to be studied as electrocatalysts for fuel cells. Therefore, many excellent core-shell catalysts have been fabricated, but few studies have reported the real application of these catalysts in a practical device actual application. In this paper, we demonstrate the use of platinum (Pt)-exoskeleton structure nanoparticles as cathode catalysts with high stability and remarkable Pt mass activity and report the outstanding performance of these materials when used in membrane-electrode assemblies (MEAs) within a polymer electrolyte membrane fuel cell. The stability and degradation characteristics of these materials were also investigated in single cells in an accelerated degradation test using load cycling, which is similar to the drive cycle of a polymer electrolyte membrane fuel cell used in vehicles. The MEAs with Pt-exoskeleton structure catalysts showed enhanced performance throughout the single cell test and exhibited improved degradation ability that differed from that of a commercial Pt/C catalyst.

Aqueous rechargeable zinc/sodium vanadate batteries with enhanced performance from simultaneous insertion of dual carriers.

PubMed

Wan, Fang; Zhang, Linlin; Dai, Xi; Wang, Xinyu; Niu, Zhiqiang; Chen, Jun

2018-04-25

Rechargeable aqueous zinc-ion batteries are promising energy storage devices due to their high safety and low cost. However, they remain in their infancy because of the limited choice of positive electrodes with high capacity and satisfactory cycling performance. Furthermore, their energy storage mechanisms are not well established yet. Here we report a highly reversible zinc/sodium vanadate system, where sodium vanadate hydrate nanobelts serve as positive electrode and zinc sulfate aqueous solution with sodium sulfate additive is used as electrolyte. Different from conventional energy release/storage in zinc-ion batteries with only zinc-ion insertion/extraction, zinc/sodium vanadate hydrate batteries possess a simultaneous proton, and zinc-ion insertion/extraction process that is mainly responsible for their excellent performance, such as a high reversible capacity of 380 mAh g -1 and capacity retention of 82% over 1000 cycles. Moreover, the quasi-solid-state zinc/sodium vanadate hydrate battery is also a good candidate for flexible energy storage device.

Rocket-Based Combined Cycle Engine Technology Development: Inlet CFD Validation and Application

NASA Technical Reports Server (NTRS)

DeBonis, J. R.; Yungster, S.

1996-01-01

A CFD methodology has been developed for inlet analyses of Rocket-Based Combined Cycle (RBCC) Engines. A full Navier-Stokes analysis code, NPARC, was used in conjunction with pre- and post-processing tools to obtain a complete description of the flow field and integrated inlet performance. This methodology was developed and validated using results from a subscale test of the inlet to a RBCC 'Strut-Jet' engine performed in the NASA Lewis 1 x 1 ft. supersonic wind tunnel. Results obtained from this study include analyses at flight Mach numbers of 5 and 6 for super-critical operating conditions. These results showed excellent agreement with experimental data. The analysis tools were also used to obtain pre-test performance and operability predictions for the RBCC demonstrator engine planned for testing in the NASA Lewis Hypersonic Test Facility. This analysis calculated the baseline fuel-off internal force of the engine which is needed to determine the net thrust with fuel on.

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.

Highly improved voltage efficiency of seawater battery by use of chloride ion capturing electrode

NASA Astrophysics Data System (ADS)

Kim, Kyoungho; Hwang, Soo Min; Park, Jeong-Sun; Han, Jinhyup; Kim, Junsoo; Kim, Youngsik

2016-05-01

Cost-effective and eco-friendly battery system with high energy density is highly desirable. Herein, we report a seawater battery with a high voltage efficiency, in which a chloride ion-capturing electrode (CICE) consisting of Ag foil is utilized as the cathode. The use of Ag as the cathode leads to a sharp decrease in the voltage gaps between charge and discharge curves, based on reversible redox reaction of Ag/AgCl (at ∼2.9 V vs. Na+/Na) in a seawater catholyte during cycling. The Ag/AgCl reaction proves to be highly reversible during battery cycling. The battery employing the Ag electrode shows excellent cycling performance with a high Coulombic efficiency (98.6-98.7%) and a highly improved voltage efficiency (90.3% compared to 73% for carbonaceous cathode) during 20 cycles (total 500 h). These findings demonstrate that seawater batteries using a CICE could be used as next-generation batteries for large-scale stationary energy storage plants.

Lignocellulose-derived porous phosphorus-doped carbon as advanced electrode for supercapacitors

NASA Astrophysics Data System (ADS)

Yi, Jianan; Qing, Yan; Wu, ChuTian; Zeng, Yinxiang; Wu, Yiqiang; Lu, Xihong; Tong, Yexiang

2017-05-01

Engineering porous heteroatom-doped carbon nanomaterials with remarkable capacitive performance is highly attractive. Herein, a simple and smart method has been developed to synthesize phosphorus (P) doped carbon with hierarchical porous structure derived from lignocellulose. Hierarchically porous P doped carbon is readily obtained by the pyrolysis of lignocellulose immersed in ZnCl2/NaH2PO4 aqueous solution, and exhibits excellent capacitive properties. The as-obtained P doped porous carbon delivers a significant capacitance of 133 F g-1 (146 mF cm-2) at a high current density of 10 A g-1 with outstanding rate performance. Furthermore, the P doped carbon electrode yields a long-term cycling durability with more than 97.9% capacitance retention after 10000 cycles as well. A symmetric supercapacitor with a maximum energy density of 4.7 Wh kg-1 is also demonstrated based on these P doped carbon electrodes.

Interconnected V2O5 nanoporous network for high-performance supercapacitors.

PubMed

Saravanakumar, B; Purushothaman, Kamatchi K; Muralidharan, G

2012-09-26

Vanadium pentoxide (V(2)O(5)) has attracted attention for supercapcitor applications because of its extensive multifunctional properties. In the present study, V(2)O(5) nanoporous network was synthesized via simple capping-agent-assisted precipitation technique and it is further annealed at different temperatures. The effect of annealing temperature on the morphology, electrochemical and structural properties, and stability upon oxidation-reduction cycling has been analyzed for supercapacitor application. We achieved highest specific capacitance of 316 F g(-1) for interconnected V(2)O(5) nanoporous network. This interconnected nanoporous network creates facile nanochannels for ion diffusion and facilitates the easy accessibility of ions. Moreover, after six hundred consecutive cycling processes the specific capacitance has changed only by 24%. A simple cost-effective preparation technique of V(2)O(5) nanoporous network with excellent capacitive behavior, energy density, and stability encourages its possible commercial exploitation for the development of high-performance supercapacitors.

Multidimensional MnO2 nanohair-decorated hybrid multichannel carbon nanofiber as an electrode material for high-performance supercapacitors.

PubMed

Jun, Jaemoon; Lee, Jun Seop; Shin, Dong Hoon; Kim, Sung Gun; Jang, Jyongsik

2015-10-14

One-dimensional (1D)-structured nanomaterials represent one of the most attractive candidates for energy-storage systems due to their contribution to design simplicity, fast charge-transportation network, and their allowance for more accessible ion diffusion. In particular, 1D-structured nanomaterials with a highly complex inner-pore configuration enhance functionality by taking advantage of both the hollow and 1D structures. In this study, we report a MnO2 nanohair-decorated, hybrid multichannel carbon nanofiber (Mn_MCNF) fabricated via single-nozzle co-electrospinning of two immiscible polymer solutions, followed by carbonization and redox reactions. With improved ion accessibility, the optimized Mn_MCNF sample (Mn_MCNF_60 corresponding to a reaction duration time of 60 min for optimal MnO2 nanohair growth) exhibited a high specific capacitance of 855 F g(-1) and excellent cycling performance with ∼87.3% capacitance retention over 5000 cycles.

Colloid electrostatic self-assembly synthesis of SnO2/graphene nanocomposite for supercapacitors

NASA Astrophysics Data System (ADS)

Wang, Yankun; Liu, Yushan; Zhang, Jianmin

2015-10-01

In this paper, a simple and fast colloid electrostatic self-assembly method was adopted to prepare the SnO2/graphene nanocomposite (SGNC). The crystal structure, chemical composition, and porous property of composite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman microscopy, X-ray photoelectron spectroscopy (XPS), and N2 adsorption-desorption experiments. The morphology analyses showed that the SnO2 nanoparticles about 5 nm were distributed homogenously on the reduced graphene oxide (rGO) sheets surface. The electrochemical performance measurements exhibited that SGNC possessed the specific capacitance of 347.3 F g-1 at a scan rate of 5 mV s-1 in 1 M Na2SO4 electrolyte solution. Furthermore, this material also showed excellent cycling stability, and the specific capacitance still retained 90 % after 3000 cycles. These results indicate that the SGNC is a promising electrode material for high-performance supercapacitors.

Hierarchical Mesoporous Zinc-Nickel-Cobalt Ternary Oxide Nanowire Arrays on Nickel Foam as High-Performance Electrodes for Supercapacitors.

PubMed

Wu, Chun; Cai, Junjie; Zhang, Qiaobao; Zhou, Xiang; Zhu, Ying; Shen, Pei Kang; Zhang, Kaili

2015-12-09

Nickel foam supported hierarchical mesoporous Zn-Ni-Co ternary oxide (ZNCO) nanowire arrays are synthesized by a simple two-step approach including a hydrothermal method and subsequent calcination process and directly utilized for supercapacitive investigation for the first time. The nickel foam supported hierarchical mesoporous ZNCO nanowire arrays possess an ultrahigh specific capacitance value of 2481.8 F g(-1) at 1 A g(-1) and excellent rate capability of about 91.9% capacitance retention at 5 A g(-1). More importantly, an asymmetric supercapacitor with a high energy density (35.6 Wh kg(-1)) and remarkable cycle stability performance (94% capacitance retention over 3000 cycles) is assembled successfully by employing the ZNCO electrode as positive electrode and activated carbon as negative electrode. The remarkable electrochemical behaviors demonstrate that the nickel foam supported hierarchical mesoporous ZNCO nanowire array electrodes are highly desirable for application as advanced supercapacitor electrodes.

Design, fabrication, and performance of foil journal bearing for the brayton rotating unit

NASA Technical Reports Server (NTRS)

Licht, L.; Branger, M.

1973-01-01

Foil bearings were designed and manufactured to replace pivoted-shoe journal bearings in an existing Brayton Cycle turbo-alternator-compressor. The design of this unconventional rotor support was accomplished within the constraints and space limitations imposed by the present machine, and the substitution of foil bearings was effected without changes or modification other machine components. A housing and a test rig were constructed to incorporate the new foil-bearing support into a unified assemble with an air-driven rotor and the gimbal-mounted thrust bearing, seals, and shrouds of an actual Brayton Rotating Unit. The foil bearing required no external pressure source, and stable self-acting rotation was achieved at all speeds up to 43,200 rpm. Excellent wipe-wear characteristics of the foil bearing permitted well over 1000 start-stop cycles with no deterioriation of performance in the entire speed range.

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.

Polymer-Templated LiFePO4/C Nanonetworks as High-Performance Cathode Materials for Lithium-Ion Batteries.

PubMed

Fischer, Michael G; Hua, Xiao; Wilts, Bodo D; Castillo-Martínez, Elizabeth; Steiner, Ullrich

2018-01-17

Lithium iron phosphate (LFP) is currently one of the main cathode materials used in lithium-ion batteries due to its safety, relatively low cost, and exceptional cycle life. To overcome its poor ionic and electrical conductivities, LFP is often nanostructured, and its surface is coated with conductive carbon (LFP/C). Here, we demonstrate a sol-gel based synthesis procedure that utilizes a block copolymer (BCP) as a templating agent and a homopolymer as an additional carbon source. The high-molecular-weight BCP produces self-assembled aggregates with the precursor-sol on the 10 nm scale, stabilizing the LFP structure during crystallization at high temperatures. This results in a LFP nanonetwork consisting of interconnected ∼10 nm-sized particles covered by a uniform carbon coating that displays a high rate performance and an excellent cycle life. Our "one-pot" method is facile and scalable for use in established battery production methodologies.

Electrochemical performance of carbon-coated lithium manganese silicate for asymmetric hybrid supercapacitors

NASA Astrophysics Data System (ADS)

Karthikeyan, K.; Aravindan, V.; Lee, S. B.; Jang, I. C.; Lim, H. H.; Park, G. J.; Yoshio, M.; Lee, Y. S.

Nanoscale carbon-coated Li 2MnSiO 4 powder is prepared using a conventional solid-state method and can be used as the negative electrode in a Li 2MnSiO 4/activated carbon (AC) hybrid supercapacitor. Carbon-coated Li 2MnSiO 4 material presents a well-developed orthorhombic crystal structure with a P mn2 1 space group, although there is a small impurity of MnO. The maximum specific capacitance of the Li 2MnSiO 4/AC hybrid supercapacitor is 43.2 F g -1 at 1 mA cm -2 current density. The cell delivers a specific energy as high as 54 Wh kg -1 at a specific power of 150 W kg -1 and also exhibits an excellent cycle performance with more than 99% columbic efficiency and the maintenance of 85% of its initial capacitance after 1000 cycles.

Self-assembled asymmetric membrane containing micron-size germanium for high capacity lithium ion batteries

DOE PAGES

Byrd, Ian; Chen, Hao; Webber, Theron; ...

2015-10-23

We report the formation of novel asymmetric membrane electrode containing micron-size (~5 μm) germanium powders through a self-assembly phase inversion method for high capacity lithium ion battery anode. 850 mA h g -1 capacity (70%) can be retained at a current density of 600 mA g -1 after 100 cycles with excellent rate performance. Such a high retention rate has rarely been seen for pristine micron-size germanium anodes. Moreover, scanning electron microscope studies reveal that germanium powders are uniformly embedded in a networking porous structure consisting of both nanopores and macropores. It is believed that such a unique porous structuremore » can efficiently accommodate the ~260% volume change during germanium alloying and de-alloying process, resulting in an enhanced cycling performance. Finally, these porous membrane electrodes can be manufactured in large scale using a roll-to-roll processing method.« less

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.

Piezoresistive Sensor with High Elasticity Based on 3D Hybrid Network of Sponge@CNTs@Ag NPs.

PubMed

Zhang, Hui; Liu, Nishuang; Shi, Yuling; Liu, Weijie; Yue, Yang; Wang, Siliang; Ma, Yanan; Wen, Li; Li, Luying; Long, Fei; Zou, Zhengguang; Gao, Yihua

2016-08-31

Pressure sensors with high elasticity are in great demand for the realization of intelligent sensing, but there is a need to develope a simple, inexpensive, and scalable method for the manufacture of the sensors. Here, we reported an efficient, simple, facile, and repeatable "dipping and coating" process to manufacture a piezoresistive sensor with high elasticity, based on homogeneous 3D hybrid network of carbon nanotubes@silver nanoparticles (CNTs@Ag NPs) anchored on a skeleton sponge. Highly elastic, sensitive, and wearable sensors are obtained using the porous structure of sponge and the synergy effect of CNTs/Ag NPs. Our sensor was also tested for over 2000 compression-release cycles, exhibiting excellent elasticity and cycling stability. Sensors with high performance and a simple fabrication process are promising devices for commercial production in various electronic devices, for example, sport performance monitoring and man-machine interfaces.

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

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.

Scalable Self-Propagating High-Temperature Synthesis of Graphene for Supercapacitors with Superior Power Density and Cyclic Stability.

PubMed

Li, Chen; Zhang, Xiong; Wang, Kai; Sun, Xianzhong; Liu, Guanghua; Li, Jiangtao; Tian, Huanfang; Li, Jianqi; Ma, Yanwei

2017-02-01

An ultrafast self-propagating high-temperature synthesis technique offers scalable routes for the fabrication of mesoporous graphene directly from CO 2 . Due to the excellent electrical conductivity and high ion-accessible surface area, supercapacitor electrodes based on the obtained graphene exhibit superior energy and power performance. The capacitance retention is higher than 90% after one million charge/discharge cycles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of Ultra-Low Platinum Alloy Cathode Catalysts for PEM Fuel Cells

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

Popov, Branko N.; Weidner, John

2016-01-07

The goal of this project is to synthesize a low cost PEM fuel cell cathode catalyst and support with optimized average mass activity, stability of mass activity, initial high current density performance under H 2/air (power density), and catalyst and support stability able to meet 2017 DOE targets for electrocatalysts for transportation applications. Pt*/ACCS-2 catalyst was synthesized according to a novel methodology developed at USC through: (i) surface modification, (ii) metal catalyzed pyrolysis and (iii) chemical leaching to remove excess meal used to dope the support. Pt* stands for suppressed platinum catalyst synthesized with Co doped platinum. The procedure resultsmore » in increasing carbon graphitization, inclusion of cobalt in the bulk and formation of non-metallic active sites on the carbon surface. Catalytic activity of the support shows an onset potential of 0.86 V for the oxygen reduction reaction (ORR) with well-defined kinetic and mass transfer regions and 2.5% H 2O 2 production. Pt*/ACCS-2 catalyst durability under 0.6-1.0 V potential cycling and support stability under 1.0-1.5 V potential cycling was evaluated. The results indicated excellent catalyst and support performance under simulated start-up/shut down operating conditions (1.0 – 1.5 V, 5000 cycles) which satisfy DOE 2017 catalyst and support durability and activity. The 30% Pt*/ACCS-2 catalyst showed high initial mass activity of 0.34 A/mg PGM at 0.9 ViR-free and loss of mass activity of 45% after 30,000 cycles (0.6-1.0 V). The catalyst performance under H 2-air fuel cell operating conditions showed only 24 mV (iR-free) loss at 0.8 A/cm 2 with an ECSA loss of 42% after 30,000 cycles (0.6-1.0 V). The support stability under 1.0-1.5 V potential cycling showed mass activity loss of 50% and potential loss of 8 mV (iR-free) at 1.5 A/cm 2. The ECSA loss was 22% after 5,000 cycles. Furthermore, the Pt*/ACCS-2 catalyst showed an initial power density (rated) of 0.174 g PGM/kW. Excellent activity and stability of the catalyst are due to synergistic effect of the catalytic activity and stability of ACCS-2, its enhanced hydrophobicity as well as activity of compressive Pt* lattice catalysts. For the first time, we report a carbon based support which is stable under simulated start-up/shut down operating conditions. Five 25cm 2 MEA’s were fabricated at USC using Pt*/ACCS-2 cathode catalyst for independent evaluation at National Renewable Energy. In the Final NREL report they summarize their results as follow: (1) Initial ORR activity and performance of the USC MEA’s Pt*/ACCS-2 under oxygen air, evaluated at NREL were comparable to that measured and reported by USC in their report: (2) Cyclic durability studies indicate that Pt*/ACCS-2 catalysts has minimal losses in activity and performant under 1-1.5 V potential cycling indicating a robust corrosion resistant support.« less

Si/Ti2O3/Reduced Graphene Oxide Nanocomposite Anodes for Lithium-Ion Batteries with Highly Enhanced Cyclic Stability.

PubMed

Park, A Reum; Son, Dae-Yong; Kim, Jung Sub; Lee, Jun Young; Park, Nam-Gyu; Park, Juhyun; Lee, Joong Kee; Yoo, Pil J

2015-08-26

Silicon (Si) has attracted tremendous attention as a high-capacity anode material for next generation Li-ion batteries (LIBs); unfortunately, it suffers from poor cyclic stability due to excessive volume expansion and reduced electrical conductivity after repeated cycles. To circumvent these issues, we propose that Si can be complexed with electrically conductive Ti2O3 to significantly enhance the reversible capacity and cyclic stability of Si-based anodes. We prepared a ternary nanocomposite of Si/Ti2O3/reduced graphene oxide (rGO) using mechanical blending and subsequent thermal reduction of the Si, TiO2 nanoparticles, and rGO nanosheets. As a result, the obtained ternary nanocomposite exhibited a specific capacity of 985 mAh/g and a Coulombic efficiency of 98.4% after 100 cycles at a current density of 100 mA/g. Furthermore, these ternary nanocomposite anodes exhibited outstanding rate capability characteristics, even with an increased current density of 10 A/g. This excellent electrochemical performance can be ascribed to the improved electron and ion transport provided by the Ti2O3 phase within the Si domains and the structurally reinforced conductive framework comprised of the rGO nanosheets. Therefore, it is expected that our approach can also be applied to other anode materials to enable large reversible capacity, excellent cyclic stability, and good rate capability for high-performance LIBs.

Hydrothermally formed three-dimensional hexagon-like P doped Ni(OH)2 rod arrays for high performance all-solid-state asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Li, Kunzhen; Li, Shikuo; Huang, Fangzhi; Lu, Yan; Wang, Lei; Chen, Hong; Zhang, Hui

2018-01-01

Three dimensional hexagon-like phosphrous (P) doped Ni(OH)2 rod arrays grown on Ni foam (NF) are fabricated by a facile and green one-step hydrothermal process. Ni foam is only reacted in a certain concentration of P containing H2O2 aqueous solution. The possible growth mechanism of the P doped Ni(OH)2 rod arrays is discussed. As a battery-type electrode material in situ formed on Ni foam, the binder-free P doped Ni(OH)2 rod arrays electrode displays a ultrahigh specific areal capacitance of 2.11C cm-2 (3.51 F cm-2) at 2 mA cm-2, and excellent cycling stability (95.5% capacitance retention after 7500 cycles). The assembled all-solid-state asymmetric supercapacitor (AAS) based on such P doped Ni(OH)2 rod arrays as the positive electrode and activated carbon as the negative electrode achieves an energy density of 81.3 Wh kg-1 at the power density of 635 W kg-1. The AAS device also exhibits excellent practical performance, which can easily drive an electric fan (3 W rated power) when two AAS devices are assembled in series. Thus, our synthesized P doped Ni(OH)2 rod arrays has a lot of potential applications in future energy storage prospects.

1D Cu(OH)2 nanorod/2D SnO2 nanosheets core/shell structured array: Covering with graphene layer leads to excellent performances on lithium-ion battery

NASA Astrophysics Data System (ADS)

Xia, Huicong; Zhang, Jianan; Chen, Zhimin; Xu, Qun

2018-05-01

A facile in-situ growth strategy is employ to achieving the two-dimensional SnO2 nanosheets/one-dimensional Cu(OH)2 nanorods nanoarchitecture on Cu foil current collector (SnO2/Cu(OH)2/Cu foil), follow by modification of a uniform layer of graphene (G). Confine with the graphene layer and unique one-dimensional/two-dimensional the nanoarchitecture, the remarkably enhance electrical conductivity and structural stability of G/SnO2/Cu(OH)2/Cu foil leads to a high reversible capacity of 1080.6 mAh g-1 at a current density of 200 mA g-1, much better than the samples without graphene (512.6 mAh g-1) and Cu(OH)2 nanorod (117.4 mAh g-1). Furthermore, G/SnO2/Cu(OH)2/Cu foil electrode shows high rate capacity (600.8 mAh g-1 at 1 A g-1) and excellent cycling stability (1057.1 mAh g-1 at 200 mA g-1 even after 500 cycles). This work highlights that increasing surface and interface effects with desirable three-dimensional nanoarchitecture can open a new avenue to electrochemical performance improvement in lithium-ion battery for SnO2-base anode.

CeO2 nanocubes-graphene oxide as durable and highly active catalyst support for proton exchange membrane fuel cell

PubMed Central

Lei, M.; Wang, Z. B.; Li, J. S.; Tang, H. L.; Liu, W. J.; Wang, Y. G.

2014-01-01

Rapid degradation of cell performance still remains a significant challenge for proton exchange membrane fuel cell (PEMFC). In this work, we develop novel CeO2 nanocubes-graphene oxide nanocomposites as durable and highly active catalyst support for proton exchange membrane fuel cell. We show that the use of CeO2 as the radical scavenger in the catalysts remarkably improves the durability of the catalyst. The catalytic activity retention of Pt-graphene oxide-8 wt.% CeO2 nanocomposites reaches as high as 69% after 5000 CV-cycles at a high voltage range of 0.8–1.23 V, in contrast to 19% for that of the Pt-graphene oxide composites. The excellent durability of the Pt-CeO2 nanocubes-graphene oxide catalyst is attributed to the free radical scavenging activity of CeO2, which significantly slows down the chemical degradation of Nafion binder in catalytic layers, and then alleviates the decay of Pt catalysts, resulting in the excellent cycle life of Pt-CeO2-graphene oxide nanocomposite catalysts. Additionally, the performance of single cell assembled with Nafion 211 membrane and Pt-CeO2-graphene oxide catalysts with different CeO2 contents in the cathode as well as the Pt-C catalysts in the anode are also recorded and discussed in this study. PMID:25491655

Novel synthesis of holey reduced graphene oxide (HRGO) by microwave irradiation method for anode in lithium-ion batteries

PubMed Central

Alsharaeh, Edreese; Ahmed, Faheem; Aldawsari, Yazeed; Khasawneh, Majdi; Abuhimd, Hatem; Alshahrani, Mohammad

2016-01-01

In this work, holey reduced graphene oxide (HRGO) was synthesized by the deposition of silver (Ag) nanoparticles onto the reduced graphene oxide (RGO) sheets followed by nitric acid treatment to remove Ag nanoparticles by microwave irradiation to form a porous structure. The HRGO were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), and Raman spectroscopy. These novel HRGO exhibited high rate capability with excellent cycling stability as an anode material for lithium-ion batteries. The results have shown an excellent electrochemical response in terms of charge/discharge capacity (423 mAh/g at 100 mA/g). The cyclic performance was also exceptional as a high reversible capacity (400 mAh/g at 100 mA/g) was retained for 100 charge/discharge cycles. This fascinating electrochemical performance can be ascribed to their specific porous structure (2–5 nm pores) and high surface area (457 m2/g), providing numerous active sites for Li+ insertion, high electrical conductivity, low charge-transfer resistance across the electrolyte–electrode interface, and improved structural stability against the local volume change during Li+ insertion–extraction. Such electrodes are envisioned to be mass scalable with relatively simple and low-cost fabrication procedures, thereby providing a clear pathway toward commercialization. PMID:27457356

CeO2 nanocubes-graphene oxide as durable and highly active catalyst support for proton exchange membrane fuel cell.

PubMed

Lei, M; Wang, Z B; Li, J S; Tang, H L; Liu, W J; Wang, Y G

2014-12-10

Rapid degradation of cell performance still remains a significant challenge for proton exchange membrane fuel cell (PEMFC). In this work, we develop novel CeO2 nanocubes-graphene oxide nanocomposites as durable and highly active catalyst support for proton exchange membrane fuel cell. We show that the use of CeO2 as the radical scavenger in the catalysts remarkably improves the durability of the catalyst. The catalytic activity retention of Pt-graphene oxide-8 wt.% CeO2 nanocomposites reaches as high as 69% after 5000 CV-cycles at a high voltage range of 0.8-1.23 V, in contrast to 19% for that of the Pt-graphene oxide composites. The excellent durability of the Pt-CeO2 nanocubes-graphene oxide catalyst is attributed to the free radical scavenging activity of CeO2, which significantly slows down the chemical degradation of Nafion binder in catalytic layers, and then alleviates the decay of Pt catalysts, resulting in the excellent cycle life of Pt-CeO2-graphene oxide nanocomposite catalysts. Additionally, the performance of single cell assembled with Nafion 211 membrane and Pt-CeO2-graphene oxide catalysts with different CeO2 contents in the cathode as well as the Pt-C catalysts in the anode are also recorded and discussed in this study.

CeO2 nanocubes-graphene oxide as durable and highly active catalyst support for proton exchange membrane fuel cell

NASA Astrophysics Data System (ADS)

Lei, M.; Wang, Z. B.; Li, J. S.; Tang, H. L.; Liu, W. J.; Wang, Y. G.

2014-12-01

Rapid degradation of cell performance still remains a significant challenge for proton exchange membrane fuel cell (PEMFC). In this work, we develop novel CeO2 nanocubes-graphene oxide nanocomposites as durable and highly active catalyst support for proton exchange membrane fuel cell. We show that the use of CeO2 as the radical scavenger in the catalysts remarkably improves the durability of the catalyst. The catalytic activity retention of Pt-graphene oxide-8 wt.% CeO2 nanocomposites reaches as high as 69% after 5000 CV-cycles at a high voltage range of 0.8-1.23 V, in contrast to 19% for that of the Pt-graphene oxide composites. The excellent durability of the Pt-CeO2 nanocubes-graphene oxide catalyst is attributed to the free radical scavenging activity of CeO2, which significantly slows down the chemical degradation of Nafion binder in catalytic layers, and then alleviates the decay of Pt catalysts, resulting in the excellent cycle life of Pt-CeO2-graphene oxide nanocomposite catalysts. Additionally, the performance of single cell assembled with Nafion 211 membrane and Pt-CeO2-graphene oxide catalysts with different CeO2 contents in the cathode as well as the Pt-C catalysts in the anode are also recorded and discussed in this study.

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.

A microwave synthesis of mesoporous NiCo2O4 nanosheets as electrode materials for lithium-ion batteries and supercapacitors.

PubMed

Mondal, Anjon Kumar; Su, Dawei; Chen, Shuangqiang; Kretschmer, Katja; Xie, Xiuqiang; Ahn, Hyo-Jun; Wang, Guoxiu

2015-01-12

A facile microwave method was employed to synthesize NiCo2 O4 nanosheets as electrode materials for lithium-ion batteries and supercapacitors. The structure and morphology of the materials were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Teller methods. Owing to the porous nanosheet structure, the NiCo2 O4 electrodes exhibited a high reversible capacity of 891 mA h g(-1) at a current density of 100 mA g(-1) , good rate capability and stable cycling performance. When used as electrode materials for supercapacitors, NiCo2 O4 nanosheets demonstrated a specific capacitance of 400 F g(-1) at a current density of 20 A g(-1) and superior cycling stability over 5000 cycles. The excellent electrochemical performance could be ascribed to the thin porous structure of the nanosheets, which provides a high specific surface area to increase the electrode-electrolyte contact area and facilitate rapid ion transport. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hierarchical TiO2-B composed of nanosheets with exposed {010} facets as a high-performance anode for lithium ion batteries

NASA Astrophysics Data System (ADS)

Liu, Yubin; Chen, Wenqiang; Yang, Chengyu; Wei, Qiaohua; Wei, Mingdeng

2018-07-01

Facet engineering of electrode materials with a special facet provides a new strategy to enhance their electrochemical properties. In the present work, hierarchical TiO2-B composed of nanosheets with exposed {010} facets are successfully synthesized via a facial hydrothermal route. When used as an anode for lithium ion batteries, this material demonstrates high capacities, excellent rata capability and remarkable cycling performance. For instance, it displays a reversible capacity of 200.9 mA h g-1 after 200 cycles at a current density of 1.675 A g-1 (5 C). Furthermore, a full cell consisted of hierarchical TiO2-B composed of nanosheets with exposed {010} facets anode and LiFePO4 cathode exhibits a high capacity of 125.6 mA h g-1 after 1000 cycles at a current density of 2 A g-1. Such outstanding electrochemical properties of this material can be attributed to hierarchical structure and the presence of exposed {010} facets which provides favorable lithium transport channels.

Enhanced electrochemical performance of sandwich-structured polyaniline-wrapped silicon oxide/carbon nanotubes for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Liu, Hui; Zou, Yongjin; Huang, Liyan; Yin, Hao; Xi, Chengqiao; Chen, Xin; Shentu, Hongwei; Li, Chao; Zhang, Jingjing; Lv, ChunJu; Fan, Meiqiang

2018-06-01

Sandwich-structured carbon nanotubes, silicon oxide, and polyaniline (hereafter denoted as CNTs/SiOx/PANI) were prepared by combining a sol-gel method, magnesiothermic reduction at 250 °C, and chemical oxidative polymerization. The CNTs, SiOx and PANI in the composite was 16 wt%, 51 wt% and 33 wt%, respectively. The CNTs/SiOx/PANI electrodes exhibited excellent cycle and high-rate performance as anodes in Li-ion batteries, including charge/discharge capacities of 1156/1178 mAh g-1 after 60 cycles at 0.2 A g-1 current density and 728/725 mAh g-1 at 8 A g-1 current density. The improvement was due to the synergy between CNTs and PANI. The SiOx scattered on the CNTs core and coated by PANI improved its conductivity and accommodated the volume change during repeated lithiation/delithiation cycles. This simple synthesis provided a scalable route for the large-scale production of CNTs/SiOx/PANI nanostructures, with various applications such as in Li-ion batteries.

Coral-Inspired Nanoengineering Design for Long-Cycle and Flexible Lithium-Ion Battery Anode.

PubMed

Sun, Yangyong; Wang, Cheng; Xue, Yinghui; Zhang, Qin; Mendes, Rafael G; Chen, Linfeng; Zhang, Tao; Gemming, Thomas; Rümmeli, Mark H; Ai, Xinping; Fu, Lei

2016-04-13

Conversion reaction electrode materials (CREMs) have gained significant interest in lithium-ion batteries (LIBs) owing to their high theoretical gravimetric capacity. However, traditional CREMs-based electrodes, with large strain arising from Li(+) intercalation/deintercalation causes pulverization or electrical breakdown and cracking of the active materials which leads to structural collapse, limiting performance. Therefore, in order to construct electrodes with a strong tolerance to the strain incurred during the conversion reaction process, we design a coral-like three-dimensional (3D) hierarchical heterostructure by using cross-linked nanoflakes interspersed with nanoparticles (NPs) standing vertically on graphene foam (GF). The coral-like 3D hierarchical heterostructures can efficiently disperse the strain from both internal and external forces as well as increase the specific surface area for enhanced electrochemical reactions. These features lead to long-cycle stability and excellent flexibility in LIBs. Fe3O4 NPs and CoO NFs are utilized as a model system to demonstrate our strategy. The as-prepared coral-like hierarchical electrode is studied as an anode in LIBs for the first time and is shown to deliver a high reversible specific gravimetric capacity of ∼1200 mA h g(-1) at a rate of 0.5 A g(-1) for 400 cycles. In addition, our batteries can even power a green light-emitting diode when bent to high degrees confirming the excellent flexibility of the material.

Center-iodized graphene as an advanced anode material to significantly boost the performance of lithium-ion batteries.

PubMed

Chen, Jie; Xu, Mao-Wen; Wu, Jinggao; Li, Chang Ming

2018-05-17

Iodine edge-doped graphene can improve the capacity and stability of lithium-ion batteries (LIBs). Our theoretical calculations indicate that center-iodization can further significantly enhance the anode catalytic process. To experimentally prove the theoretical prediction, iodine-doped graphene materials were prepared by one-pot hydrothermal and ball-milling approaches to realize different doping-sites. Results show that the center-iodinated graphene (CIG) anode exhibits a remarkably high reversible capacity (1121 mA h g-1 after 180 cycles at 0.5 A g-1), long-cycle life (0.01% decay per cycle over 300 cycles at 1 A g-1) and high-rate capacity (374 mA h g-1 after 800 cycles at 8 A g-1), which greatly improves the performance of the edge-iodinated graphene anode and these results are in good agreement with the theoretical analysis. More importantly, the CIG anode also delivers a high-rate capacity and excellent cycling stability (279 mA h g-1 after 500 cycles at 10 A g-1) in full-cells. Both the theoretical analysis and experimental investigation reveal the enhancement mechanism, in which the center-iodization increases the surface charge for fast electron transfer rate, improves the conductivity for charge transport and rationalizes the pore structure for enhanced mass transport and ion insertion/desertion, thus resulting in a high rate capacity and long cycle life. This work not only discloses the critical role of catalytic sites including both amounts and site positions but also offers great potential for high-power rechargeable LIB applications.

Amorphous Transition Metal Sulfides Anchored on Amorphous Carbon-Coated Multiwalled Carbon Nanotubes for Enhanced Lithium-Ion Storage.

PubMed

Jin, Rencheng; Zhai, Qinghe; Wang, Qingyao

2017-10-09

Cobalt sulfide and molybdenum sulfide, with high theoretical capacities, have been considered as one of most promising anode materials for lithium-ion batteries (LIBs). However, the poor cyclability and low rate performances originating from the large volume expansion and poor electrical conductivity extremely inhibit their practical application. Here, the electrochemical performances are effectively improved by growing amorphous cobalt sulfide and molybdenum sulfide onto amorphous carbon-coated multiwalled carbon nanotubes (CNTs@C@CoS 2 and CNTs@C@MoS 2 ). The CNTs@C@CoS 2 presents a high reversible specific capacity of 1252 mAh g -1 at 0.2 Ag -1 , excellent rate performance of 672 mAh g -1 (5 Ag -1 ), and enhanced cycle life of 598 mAh g -1 after 500 cycles at 2 Ag -1 . For CNTs@C@MoS 2 , it exhibits a specific capacity of 1395 mAh g -1 , superior rate performance of 727 mAh g -1 at 5 Ag -1 , and long cycle stability (796 mAh g -1 after 500 cycles at 2 Ag -1 ). The enhanced electrochemical properties of the electrodes are probably ascribed to their amorphous nature, the combination of CNTs@C that adhered and hindered the agglomeration of CoS 2 and MoS 2 as well as the enhanced electronic conductivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nitrogen-Doped Porous Carbon Nanosheets from Eco-Friendly Eucalyptus Leaves as High Performance Electrode Materials for Supercapacitors and Lithium Ion Batteries.

PubMed

Mondal, Anjon Kumar; Kretschmer, Katja; Zhao, Yufei; Liu, Hao; Wang, Chengyin; Sun, Bing; Wang, Guoxiu

2017-03-13

Nitrogen-doped porous carbon nanosheets were prepared from eucalyptus tree leaves by simply mixing the leaf powders with KHCO 3 and subsequent carbonisation. Porous carbon nanosheets with a high specific surface area of 2133 m 2  g -1 were obtained and applied as electrode materials for supercapacitors and lithium ion batteries. For supercapacitor applications, the porous carbon nanosheet electrode exhibited a supercapacitance of 372 F g -1 at a current density of 500 mA g -1 in 1 m H 2 SO 4 aqueous electrolyte and excellent cycling stability over 15 000 cycles. In organic electrolyte, the nanosheet electrode showed a specific capacitance of 71 F g -1 at a current density of 2 Ag -1 and stable cycling performance. When applied as the anode material for lithium ion batteries, the as-prepared porous carbon nanosheets also demonstrated a high specific capacity of 819 mA h g -1 at a current density of 100 mA g -1 , good rate capability, and stable cycling performance. The outstanding electrochemical performances for both supercapacitors and lithium ion batteries are derived from the large specific surface area, porous nanosheet structure and nitrogen doping effects. The strategy developed in this paper provides a novel route to utilise biomass-derived materials for low-cost energy storage systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of Mg doping on the remarkably enhanced electrochemical performance of Na 3V 2(PO 4) 3 cathode materials for sodium ion batteries

DOE PAGES

Li, Hui; Yu, Xiqian; Bai, Ying; ...

2015-01-01

Na 3V 2-xMg x(PO 4) 3/C composites with different Mg 2+ doping contents (x=0, 0.01, 0.03, 0.05, 0.07 and 0.1) were prepared by a facile sol-gel method. The doping effects on the crystal structure were investigated by XRD, XPS and EXAFS. The results show that low dose doping Mg 2+ does not alter the structure of the material, and magnesium is successfully substituted for vanadium site. The Mg doped Na 3V 2-xMg x(PO 4) 3/C composites exhibit significant improvements on the electrochemistry performances in terms of the rate capability and cycle performance, especially for the Na 3V 1.95Mg 0.05(PO 4)more » 3/C. For example, when the current density increased from 1 C to 30 C, the specific capacity only decreased from 112.5 mAh g-1 to 94.2 mAh g -1 showing very good rate capability. Moreover, even cycling at a high rate of 20 C, an excellent capacity retention of 81% is maintained from the initial value of 106.4 mAh g-1 to 86.2 mAh g-1 at the 50th cycle. Enhanced rate capability and cycle performance can be attributed to the optimized particle size, structural stability and enhanced ionic and electronic conductivity induced by Mg doping.« less

700 F hybrid capacitors cells composed of activated carbon and Li4Ti5O12 microspheres with ultra-long cycle life

NASA Astrophysics Data System (ADS)

Ruan, Dianbo; Kim, Myeong-Seong; Yang, Bin; Qin, Jun; Kim, Kwang-Bum; Lee, Sang-Hyun; Liu, Qiuxiang; Tan, Lei; Qiao, Zhijun

2017-10-01

To address the large-scale application demands of high energy density, high power density, and long cycle lifetime, 700-F hybrid capacitor pouch cells have been prepared, comprising ∼240-μm-thick activated carbon cathodes, and ∼60-μm-thick Li4Ti5O12 anodes. Microspherical Li4Ti5O12 (M-LTO) synthesized by spray-drying features 200-400 nm primary particles and interconnected nanopore structures. M-LTO half-cells exhibits high specific capacities (175 mAhh g-1), good rate capabilities (148 mAhh g-1 at 20 C), and ultra-long cycling stabilities (90% specific capacity retention after 10,000 cycles). In addition, the obtained hybrid capacitors comprising activated carbon (AC) and M-LTO shows excellent cell performances, achieving a maximum energy density of 51.65 Wh kg-1, a maximum power density of 2466 W kg-1, and ∼92% capacitance retention after 10,000 cycles, thus meeting the demands for large-scale applications such as trolleybuses.

High performance red phosphorus electrode in ionic liquid-based electrolyte for Na-ion batteries

NASA Astrophysics Data System (ADS)

Dahbi, Mouad; Fukunishi, Mika; Horiba, Tatsuo; Yabuuchi, Naoaki; Yasuno, Satoshi; Komaba, Shinichi

2017-09-01

Electrochemical performance of the red phosphorus electrode was examined in ionic-liquid electrolyte, 0.25 mol dm-3 sodium bisfluorosulfonylamide (NaFSA) dissolved N-methyl-N-propylpyridinium-bisfluorosulfonylamide (MPPFSA), at room temperature. We compared its electrochemical performance to conventional EC/PC/DEC, EC/DEC, and PC solutions containing 1 mol dm-3 NaPF6. The electrode in NaFSA/MPPFSA demonstrated a reversible capacity of 1480 mAh g-1 and excellent capacity retention of 93% over 80 cycles, which is much better than those in the conventional electrolytes. The difference in capacity retention for the electrolytes correlates to the different solid electrolyte interphase (SEI) layer formed on the phosphorus electrode. To understand the SEI formation in NaFSA/MPPFSA and its evolution during cycling, we investigate the surface layer of the red phosphorus electrodes with hard X-ray photoelectron spectroscopy (HAXPES) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). A detailed analysis of HAXPES spectra demonstrates that SEI layer consists of major inorganic and minor organic species, originating from decomposition of MPP+ and FSA-. Homogenous surface layer is formed during the first cycle in NaFSA/MPPFSA while in alkyl carbonate ester electrolytes, continuous growth of surface film up to the 20th cycle is observed. Possibility of red phosphorous electrode for battery applications with pure ionic liquid is discussed.

High-performance graphene/sulphur electrodes for flexible Li-ion batteries using the low-temperature spraying method.

PubMed

Kumar, Pushpendra; Wu, Feng-Yu; Hu, Lung-Hao; Ali Abbas, Syed; Ming, Jun; Lin, Chia-Nan; Fang, Jason; Chu, Chih-Wei; Li, Lain-Jong

2015-05-07

Elementary sulphur (S) has been shown to be an excellent cathode material in energy storage devices such as Li-S batteries owing to its very high capacity. The major challenges associated with the sulphur cathodes are structural degradation, poor cycling performance and instability of the solid-electrolyte interphase caused by the dissolution of polysulfides during cycling. Tremendous efforts made by others have demonstrated that encapsulation of S materials improves their cycling performance. To make this approach practical for large scale applications, the use of low-cost technology and materials has become a crucial and new focus of S-based Li-ion batteries. Herein, we propose to use a low temperature spraying process to fabricate graphene/S electrode material, where the ink is composed of graphene flakes and the micron-sized S particles prepared by grinding of low-cost S powders. The S particles are found to be well hosted by highly conductive graphene flakes and consequently superior cyclability (∼70% capacity retention after 250 cycles), good coulombic efficiency (∼98%) and high capacity (∼1500 mA h g(-1)) are obtained. The proposed approach does not require high temperature annealing or baking; hence, another great advantage is to make flexible Li-ion batteries. We have also demonstrated two types of flexible batteries using sprayed graphene/S electrodes.

Nitrogen doped carbon derived from polyimide/multiwall carbon nanotube composites for high performance flexible all-solid-state supercapacitors

NASA Astrophysics Data System (ADS)

Kim, Dae Kyom; Kim, Nam Dong; Park, Seung-Keun; Seong, Kwang-dong; Hwang, Minsik; You, Nam-Ho; Piao, Yuanzhe

2018-03-01

Flexible all-solid-state supercapacitors are desirable as potential energy storage systems for wearable technologies. Herein, we synthesize aminophenyl multiwall carbon nanotube (AP-MWCNT) grafted polyimide precursor by in situ polymerization method as a nitrogen-doped carbon precursor. Flexible supercapacitor electrodes are fabricated via a coating of carbon precursor on carbon cloth surface and carbonization at high temperature directly. The as-obtained electrodes, which can be directly used without any binders or additives, can deliver a high specific capacitance of 333.4 F g-1 at 1 A g-1 (based on active material mass) and excellent cycle stability with 103% capacitance retention after 10,000 cycles in a three-electrode system. The flexible all-solid-state supercapacitor device exhibits a high volumetric capacitance of 3.88 F cm-3 at a current density of 0.02 mA cm-3. And also the device can deliver a maximum volumetric energy density of 0.50 mWh cm-3 and presents good cycling stability with 85.3% capacitance retention after 10,000 cycles. This device cell can not only show extraordinary mechanical flexibilities allowing folding, twisting, and rolling but also demonstrate remarkable stable electrochemical performances under their forms. This work provides a novel approach to obtain carbon textile-based flexible supercapacitors with high electrochemical performance and mechanical flexibility.

Encapsulating micro-nano Si/SiO x into conjugated nitrogen-doped carbon as binder-free monolithic anodes for advanced lithium ion batteries

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

Wang, Jing; Zhou, Meijuan; Tan, Guoqiang

2015-01-01

Silicon monoxide, a promising silicon-based anode candidate for lithium-ion batteries, has recently attracted much attention for its high theoretical capacity, good cycle stability, low cost, and environmental benignity. Currently, the most critical challenge is to improve its low initial coulombic efficiency and significant volume changes during the charge–discharge processes. Herein, we report a binder-free monolithic electrode structure based on directly encapsulating micro-nano Si/SiOx particles into conjugated nitrogen-doped carbon frameworks to form monolithic, multi-core, cross-linking composite matrices. We utilize micro-nano Si/SiOx reduced by high-energy ball-milling SiO as active materials, and conjugated nitrogen-doped carbon formed by the pyrolysis of polyacrylonitrile both asmore » binders and conductive agents. Owing to the high electrochemical activity of Si/SiOx and the good mechanical resiliency of conjugated nitrogen-doped carbon backbones, this specific composite structure enhances the utilization efficiency of SiO and accommodates its large volume expansion, as well as its good ionic and electronic conductivity. The annealed Si/SiOx/polyacrylonitrile composite electrode exhibits excellent electrochemical properties, including a high initial reversible capacity (2734 mA h g-1 with 75% coulombic efficiency), stable cycle performance (988 mA h g-1 after 100 cycles), and good rate capability (800 mA h g-1 at 1 A g-1 rate). Because the composite is naturally abundant and shows such excellent electrochemical performance, it is a promising anode candidate material for lithium-ion batteries. The binder-free monolithic architectural design also provides an effective way to prepare other monolithic electrode materials for advanced lithium-ion batteries.« less

Enhanced capacitance and rate capability of graphene/polypyrrole composite as electrode material for supercapacitors

NASA Astrophysics Data System (ADS)

Zhang, Dacheng; Zhang, Xiong; Chen, Yao; Yu, Peng; Wang, Changhui; Ma, Yanwei

Graphene and polypyrrole composite (PPy/GNS) is synthesized via in situ polymerization of pyrrole monomer in the presence of graphene under acid conditions. The structure and morphology of the composite are characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectrometer (FTIR), X-rays photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). It is found that a uniform composite is formed with polypyrrole being homogeneously surrounded by graphene nanosheets (GNS). The composite is a promising candidate for supercapacitors to have higher specific capacitance, better rate capability and cycling stability than those of pure polypyrrole. The specific capacitance of PPy/GNS composite based on the three-electrode cell configuration is as high as 482 F g -1 at a current density of 0.5 A g -1. After 1000 cycles, the attenuation of the specific capacitance is less than 5%, indicating that composite has excellent cycling performance.

Highly Conductive In-SnO2/RGO Nano-Heterostructures with Improved Lithium-Ion Battery Performance

NASA Astrophysics Data System (ADS)

Liu, Ying; Palmieri, Alessandro; He, Junkai; Meng, Yongtao; Beauregard, Nicole; Suib, Steven L.; Mustain, William E.

2016-05-01

The increasing demand of emerging technologies for high energy density electrochemical storage has led many researchers to look for alternative anode materials to graphite. The most promising conversion and alloying materials do not yet possess acceptable cycle life or rate capability. In this work, we use tin oxide, SnO2, as a representative anode material to explore the influence of graphene incorporation and In-doping to increase the electronic conductivity and concomitantly improve capacity retention and cycle life. It was found that the incorporation of In into SnO2 reduces the charge transfer resistance during cycling, prolonging life. It is also hypothesized that the increased conductivity allows the tin oxide conversion and alloying reactions to both be reversible, leading to very high capacity near 1200 mAh/g. Finally, the electrodes show excellent rate capability with a capacity of over 200 mAh/g at 10C.

Facile fabrication of cobalt oxalate nanostructures with superior specific capacitance and super-long cycling stability

NASA Astrophysics Data System (ADS)

Cheng, Guanhua; Si, Conghui; Zhang, Jie; Wang, Ying; Yang, Wanfeng; Dong, Chaoqun; Zhang, Zhonghua

2016-04-01

Transition metal oxalate materials have shown huge competitive advantages for applications in supercapacitors. Herein, nanostructured cobalt oxalate supported on cobalt foils has been facilely fabricated by anodization, and could directly serve as additive/binder-free electrodes for supercapacitors. The as-prepared cobalt oxalate electrodes present superior specific capacitance of 1269 F g-1 at the current density of 6 A g-1 in the galvanostatic charge/discharge test. Moreover, the retained capacitance is as high as 87.2% as the current density increases from 6 A g-1 to 30 A g-1. More importantly, the specific capacitance of cobalt oxalate retains 91.9% even after super-long cycling of 100,000 cycles. In addition, an asymmetric supercapacitor assembled with cobalt oxalate (positive electrode) and activated carbon (negative electrode) demonstrates excellent capacitive performance with high energy density and power density.

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.

High Per formance and Flexible Supercapacitors based on Carbonized Bamboo Fibers for Wide Temperature Applications

PubMed Central

Zequine, Camila; Ranaweera, C. K.; Wang, Z.; Singh, Sweta; Tripathi, Prashant; Srivastava, O. N.; Gupta, Bipin Kumar; Ramasamy, K.; Kahol, P. K.; Dvornic, P. R.; Gupta, Ram K.

2016-01-01

High performance carbonized bamboo fibers were synthesized for a wide range of temperature dependent energy storage applications. The structural and electrochemical properties of the carbonized bamboo fibers were studied for flexible supercapacitor applications. The galvanostatic charge-discharge studies on carbonized fibers exhibited specific capacity of ~510F/g at 0.4 A/g with energy density of 54 Wh/kg. Interestingly, the carbonized bamboo fibers displayed excellent charge storage stability without any appreciable degradation in charge storage capacity over 5,000 charge-discharge cycles. The symmetrical supercapacitor device fabricated using these carbonized bamboo fibers exhibited an areal capacitance of ~1.55 F/cm2 at room temperature. In addition to high charge storage capacity and cyclic stability, the device showed excellent flexibility without any degradation to charge storage capacity on bending the electrode. The performance of the supercapacitor device exhibited ~65% improvement at 70 °C compare to that at 10 °C. Our studies suggest that carbonized bamboo fibers are promising candidates for stable, high performance and flexible supercapacitor devices. PMID:27546225

High Per formance and Flexible Supercapacitors based on Carbonized Bamboo Fibers for Wide Temperature Applications.

PubMed

Zequine, Camila; Ranaweera, C K; Wang, Z; Singh, Sweta; Tripathi, Prashant; Srivastava, O N; Gupta, Bipin Kumar; Ramasamy, K; Kahol, P K; Dvornic, P R; Gupta, Ram K

2016-08-22

High performance carbonized bamboo fibers were synthesized for a wide range of temperature dependent energy storage applications. The structural and electrochemical properties of the carbonized bamboo fibers were studied for flexible supercapacitor applications. The galvanostatic charge-discharge studies on carbonized fibers exhibited specific capacity of ~510F/g at 0.4 A/g with energy density of 54 Wh/kg. Interestingly, the carbonized bamboo fibers displayed excellent charge storage stability without any appreciable degradation in charge storage capacity over 5,000 charge-discharge cycles. The symmetrical supercapacitor device fabricated using these carbonized bamboo fibers exhibited an areal capacitance of ~1.55 F/cm(2) at room temperature. In addition to high charge storage capacity and cyclic stability, the device showed excellent flexibility without any degradation to charge storage capacity on bending the electrode. The performance of the supercapacitor device exhibited ~65% improvement at 70 °C compare to that at 10 °C. Our studies suggest that carbonized bamboo fibers are promising candidates for stable, high performance and flexible supercapacitor devices.

High Per formance and Flexible Supercapacitors based on Carbonized Bamboo Fibers for Wide Temperature Applications

NASA Astrophysics Data System (ADS)

Zequine, Camila; Ranaweera, C. K.; Wang, Z.; Singh, Sweta; Tripathi, Prashant; Srivastava, O. N.; Gupta, Bipin Kumar; Ramasamy, K.; Kahol, P. K.; Dvornic, P. R.; Gupta, Ram K.

2016-08-01

High performance carbonized bamboo fibers were synthesized for a wide range of temperature dependent energy storage applications. The structural and electrochemical properties of the carbonized bamboo fibers were studied for flexible supercapacitor applications. The galvanostatic charge-discharge studies on carbonized fibers exhibited specific capacity of ~510F/g at 0.4 A/g with energy density of 54 Wh/kg. Interestingly, the carbonized bamboo fibers displayed excellent charge storage stability without any appreciable degradation in charge storage capacity over 5,000 charge-discharge cycles. The symmetrical supercapacitor device fabricated using these carbonized bamboo fibers exhibited an areal capacitance of ~1.55 F/cm2 at room temperature. In addition to high charge storage capacity and cyclic stability, the device showed excellent flexibility without any degradation to charge storage capacity on bending the electrode. The performance of the supercapacitor device exhibited ~65% improvement at 70 °C compare to that at 10 °C. Our studies suggest that carbonized bamboo fibers are promising candidates for stable, high performance and flexible supercapacitor devices.

MnO2-GO double-shelled sulfur (S@MnO2@GO) as a cathode for Li-S batteries with improved rate capability and cyclic performance

NASA Astrophysics Data System (ADS)

Huang, Xingkang; Shi, Keying; Yang, Joseph; Mao, George; Chen, Junhong

2017-07-01

Sulfur cathodes have attracted much attention recently because of their high energy density and power density. However, sulfur possesses very poor electrical conductivity, and lithium polysulfides, resulting from the lithiation of sulfur, are prone to dissolving into electrolytes, which leads to the loss of active materials and poor cyclic performance of the sulfur cathodes. Here we report an MnO2-graphene oxide (GO) double-shelled sulfur (S@MnO2@GO) with improved rate capability and cyclic performance, in which we propose a new reaction using sulfur-reducing KMnO4 to produce MnO2 that covers the surface of the excess sulfur in situ. The resulting MnO2 with honeycomb-like morphology provides excellent voids for storing polysulfides. The outermost GO was assembled to block the open pores of MnO2, thereby minimizing the opportunity for polysulfides to leach into the electrolytes. The GO significantly improved the electrical conductivity of the sulfur cathode, and the S@MnO2@GO exhibited excellent rate capability and long cycle life.

2D nickel oxide nanosheets with highly porous structure for high performance capacitive energy storage

NASA Astrophysics Data System (ADS)

Li, Zijiong; Zhang, Weiyang; Liu, Yanyue; Guo, Jinjin; Yang, Baocheng

2018-01-01

Developing advanced electrochemical electrode materials with excellent performance is critical to their future energy storage devices. Herein, we design and synthesize two-dimensional (2D) porous structure nickel oxide (NiO) nanosheets via a facile and scalable hydrothermal approach, and further heating. The effects of heating time on the electrochemical performances are investigated. The results indicate that the maximum specific capacitance is achieved for NiO nanosheets when heating temperature and time are 300 °C and 3 h, respectively (namely NiO-3). The as-prepared NiO-3 nanosheet are grown uniform on the skeleton of reduced graphene oxide (rGO). The optimum NiO/rGO displays a reversible discharge capacity of 781.7 F g-1 at 1 A g-1, and shows an ultra-long life-span with over 94% capacitance retention after 4000 cycles. The enhanced electrochemical properties for NiO/rGO can be ascribed to a collaborative effect between NiO and rGO, which possess high capacitance storage ability and excellent conductivity, respectively.

A hybrid ferroelectric-flash memory cells

NASA Astrophysics Data System (ADS)

Park, Jae Hyo; Byun, Chang Woo; Seok, Ki Hwan; Kim, Hyung Yoon; Chae, Hee Jae; Lee, Sol Kyu; Son, Se Wan; Ahn, Donghwan; Joo, Seung Ki

2014-09-01

A ferroelectric-flash (F-flash) memory cells having a metal-ferroelectric-nitride-oxynitride-silicon structure are demonstrated, and the ferroelectric materials were perovskite-dominated Pb(Zr,Ti)O3 (PZT) crystallized by Pt gate electrode. The PZT thin-film as a blocking layer improves electrical and memorial performance where programming and erasing mechanism are different from the metal-ferroelectric-insulator-semiconductor device or the conventional silicon-oxide-nitride-oxide-silicon device. F-flash cells exhibit not only the excellent electrical transistor performance, having 442.7 cm2 V-1 s-1 of field-effect mobility, 190 mV dec-1 of substhreshold slope, and 8 × 105 on/off drain current ratio, but also a high reliable memory characteristics, having a large memory window (6.5 V), low-operating voltage (0 to -5 V), faster P/E switching speed (50/500 μs), long retention time (>10 years), and excellent fatigue P/E cycle (>105) due to the boosting effect, amplification effect, and energy band distortion of nitride from the large polarization. All these characteristics correspond to the best performances among conventional flash cells reported so far.

B, N co-doped carbon from cross-linking induced self-organization of boronate polymer for supercapacitor and oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Chang, Ying; Yuan, Conghui; Liu, Cheng; Mao, Jie; Li, Yuntong; Wu, Haiyang; Wu, Yuzhe; Xu, Yiting; Zeng, Birong; Dai, Lizong

2017-10-01

A novel strategy has been developed to generate B, N co-doped carbon materials (CNBs) through the pyrolysis of boronate polymer nanoparticles (BPNs) derived from the condensation reaction between catechol and boronic monomers. The morphology, surface area and heteroatom (viz. B and N) content of the CNBs can be easily adjusted by altering the molar ratio between catechol and boronic monomers. The supercapacitor and oxygen reduction reaction (ORR) performance of the CNBs are optimized. CNBs derived from equal molar ratio of catechol and boronic monomers exhibit favorable performance for supercapacitor, featuring a specific capacitance of up to 299.4 F/g at 0.2 A/g, an improved rate capability and excellent cycle stability. Notably, CNBs prepared using 1/2 molar ratio of catechol to boronic monomers show excellent ORR performance, as they demonstrate good electrocatalytic activity, high tolerance for methanol and long durability. Our findings may be of interest in the design of carbon materials with optimized electrochemical properties through the control over surface area and the content of heteroatom.

Co-modification of nitrogen-doped graphene and carbon on Li3V2(PO4)3 particles with excellent long-term and high-rate performance for lithium storage

NASA Astrophysics Data System (ADS)

Ren, Manman; Yang, Mingzhi; Liu, Weiliang; Li, Mei; Su, Liwei; Wu, Xianbin; Wang, Yuanhao

2016-09-01

In this work, N-doped graphene and carbon co-modified Li3V2(PO4)3 composites (LVP/NGC) are successfully fabricated through a xerogel method for the first time. The obtained architecture combines two types of electronic contact with Li3V2(PO4)3 particles: the point-to-face contact of N-doped graphene and the face-to-face contact of N-doped carbon coating layers. Profiting from the favorable complex structure, graphene and carbon coating layers offer an extraordinary network for electron transfer and hence an excellent long-term and high-rate performance. Even tested at the rate of 40 C, the reversible capacity still maintains 86.9 mAh g-1 after 800 cycles without any fading. This work provides a promising route to improve the long-term and high-rate performance of cathodes for LIBs and enlightens us on exploring preferable strategies to develop advanced electrode materials for other energy storage devices.

Parametric (On-Design) Cycle Analysis for a Separate-Exhaust Turbofan Engine With Interstage Turbine Burner

NASA Technical Reports Server (NTRS)

Liew, K. H.; Urip, E.; Yang, S. L.; Siow, Y. K.; Marek, C. J.

2005-01-01

Today s modern aircraft is based on air-breathing jet propulsion systems, which use moving fluids as substances to transform energy carried by the fluids into power. Throughout aero-vehicle evolution, improvements have been made to the engine efficiency and pollutants reduction. The major advantages associated with the addition of ITB are an increase in thermal efficiency and reduction in NOx emission. Lower temperature peak in the main combustor results in lower thermal NOx emission and lower amount of cooling air required. This study focuses on a parametric (on-design) cycle analysis of a dual-spool, separate-flow turbofan engine with an Interstage Turbine Burner (ITB). The ITB considered in this paper is a relatively new concept in modern jet engine propulsion. The ITB serves as a secondary combustor and is located between the high- and the low-pressure turbine, i.e., the transition duct. The objective of this study is to use design parameters, such as flight Mach number, compressor pressure ratio, fan pressure ratio, fan bypass ratio, and high-pressure turbine inlet temperature to obtain engine performance parameters, such as specific thrust and thrust specific fuel consumption. Results of this study can provide guidance in identifying the performance characteristics of various engine components, which can then be used to develop, analyze, integrate, and optimize the system performance of turbofan engines with an ITB. Visual Basic program, Microsoft Excel macrocode, and Microsoft Excel neuron code are used to facilitate Microsoft Excel software to plot engine performance versus engine design parameters. This program computes and plots the data sequentially without forcing users to open other types of plotting programs. A user s manual on how to use the program is also included in this report. Furthermore, this stand-alone program is written in conjunction with an off-design program which is an extension of this study. The computed result of a selected design-point engine will be exported to an engine reference data file that is required in off-design calculation.

Faradic redox active material of Cu7S4 nanowires with a high conductance for flexible solid state supercapacitors

NASA Astrophysics Data System (ADS)

Javed, Muhammad Sufyan; Dai, Shuge; Wang, Mingjun; Xi, Yi; Lang, Qiang; Guo, Donglin; Hu, Chenguo

2015-08-01

The exploration of high Faradic redox active materials with the advantages of low cost and low toxicity has been attracting great attention for producing high energy storage supercapacitors. Here, the high Faradic redox active material of Cu7S4-NWs coated on a carbon fiber fabric (CFF) is directly used as a binder-free electrode for a high performance flexible solid state supercapacitor. The Cu7S4-NW-CFF supercapacitor exhibits excellent electrochemical performance such as a high specific capacitance of 400 F g-1 at the scan rate of 10 mV s-1 and a high energy density of 35 Wh kg-1 at a power density of 200 W kg-1, with the advantages of a light weight, high flexibility and long term cycling stability by retaining 95% after 5000 charge-discharge cycles at a constant current of 10 mA. The high Faradic redox activity and high conductance behavior of the Cu7S4-NWs result in a high pseudocapacitive performance with a relatively high specific energy and specific power. Such a new type of pseudocapacitive material of Cu7S4-NWs with its low cost is very promising for actual application in supercapacitors.The exploration of high Faradic redox active materials with the advantages of low cost and low toxicity has been attracting great attention for producing high energy storage supercapacitors. Here, the high Faradic redox active material of Cu7S4-NWs coated on a carbon fiber fabric (CFF) is directly used as a binder-free electrode for a high performance flexible solid state supercapacitor. The Cu7S4-NW-CFF supercapacitor exhibits excellent electrochemical performance such as a high specific capacitance of 400 F g-1 at the scan rate of 10 mV s-1 and a high energy density of 35 Wh kg-1 at a power density of 200 W kg-1, with the advantages of a light weight, high flexibility and long term cycling stability by retaining 95% after 5000 charge-discharge cycles at a constant current of 10 mA. The high Faradic redox activity and high conductance behavior of the Cu7S4-NWs result in a high pseudocapacitive performance with a relatively high specific energy and specific power. Such a new type of pseudocapacitive material of Cu7S4-NWs with its low cost is very promising for actual application in supercapacitors. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03363b

Ultrafast surface modification of Ni3S2 nanosheet arrays with Ni-Mn bimetallic hydroxides for high-performance supercapacitors.

PubMed

Zou, Xu; Sun, Qing; Zhang, Yuxin; Li, Guo-Dong; Liu, Yipu; Wu, Yuanyuan; Yang, Lan; Zou, Xiaoxin

2018-03-14

Amorphous Ni-Mn bimetallic hydroxide film on the three-dimensional nickle foam (NF)-supported conductive Ni 3 S 2 nanosheets (denoted as Ni-Mn-OH@Ni 3 S 2 /NF) is successfully synthesized by an ultrafast process (5 s). The fascinating structural characteristic endows Ni-Mn-OH@Ni 3 S 2 /NF electrodes better electrochemical performance. The specific capacitance of 2233.3 F g -1 at a current density of 15 A g -1 can achieve high current density charge and discharge at 20/30 A g -1 that the corresponding capacitance is 1529.16 and 1350 F g -1 , respectively. As well as good cycling performance after 1000 cycles can maintain 72% at 15 A g -1 . The excellent performance can be attributed to unique surface modification nanostructures and the synergistic effect of the bimetallic hydroxide film. The impressive results provide new opportunity to produce advanced electrode materials by simple and green route and this material is expected to apply in high energy density storage systems.

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.

Flexible Asymmetric Threadlike Supercapacitors Based on NiCo2 Se4 Nanosheet and NiCo2 O4 /Polypyrrole Electrodes.

PubMed

Wang, Qiufan; Ma, Yun; Wu, Yunlong; Zhang, Daohong; Miao, Menghe

2017-04-10

Flexible threadlike supercapacitors with improved performance are needed for many wearable electronics applications. Here, we report a high performance flexible asymmetric all-solid-state threadlike supercapacitor with a NiCo 2 Se 4 positive electrode and a NiCo 2 O 4 @PPy (PPy: polypyrrole) negative electrode. The as-prepared electrodes display outstanding volume specific capacitance (14.2 F cm -3 ) and excellent cycling performance (94 % retention after 5000 cycles at 0.6 mA) owing to their nanosheet and nanosphere structures. The asymmetric all-solid-state threadlike supercapacitor expanded the stability voltage window from 0-1.0 V to 0-1.7 V and exhibits high volume energy density (5.18 mWh cm -3 ) and superior flexibility under different bending conditions. This study provides a scalable method for fabricating high performance flexible supercapacitors from easily available materials for use in wearable and portable electronics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxygen-incorporated MoS2 microspheres with tunable interiors as novel electrode materials for supercapacitors

NASA Astrophysics Data System (ADS)

Sun, Tianhua; Li, Zhangpeng; Liu, Xiaohong; Ma, Limin; Wang, Jinqing; Yang, Shengrong

2017-06-01

In this work, a simple and facile one-step hydrothermal method is developed to synthesize oxygen-incorporated molybdenum disulphide (O-MoS2) microspheres with tunable interiors (solid, yolk-shell and hollow microstructures) by using carbon disulfide (CS2) as soft template and sulfur source simultaneously. The synthesized O-MoS2 microspheres with enlarged interlayer spacing of ca. 9.8 Å show remarkable electrochemical performances as novel electrode materials for supercapacitors (SCs). Specifically, O-MoS2 hollow microsphere exhibits optimal electrochemical performances with a high specific capacitance of 744.2 F g-1 at a current density of 1 A g-1 and a good cycling stability with ca. 77.8% capacitance retention after 10 K continuous charge-discharge cycles at a high current density of 5 A g-1, thus making it a promising electrode material for high-performance SCs. The excellent electrochemical performances are mainly attributed to the enlarged interlayer spacing and the reduced band gap owing to the oxygen incorporation in MoS2 and the hollow microstructure.

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.

Facile synthesis of CuFe2O4-Fe2O3 composite for high-performance supercapacitor electrode applications

NASA Astrophysics Data System (ADS)

Khan, Rashid; Habib, Muhammad; Gondal, Mohammed A.; Khalil, Adnan; Rehman, Zia Ur; Muhammad, Zahir; Haleem, Yasir A.; Wang, Changda; Wu, Chuan Qiang; Song, Li

2017-10-01

We report the synthesis of CuFe2O4-Fe2O3 composite material for efficient and highly stable supercapacitor electrode by using eco-friendly low-temperature co-precipitation method. The CuFe2O4-Fe2O3 composite demonstrated the highest specific capacitance of 638.24 F g-1 and excellent stability up to 2000 charge/discharge cycles. The achieved capacitance value is 16 times higher than that of pure CuFe2O4. The results revealed the extraordinary performance of CuFe2O4-Fe2O3 composite as supercapacitor electrode with excellent retention in comparison to CuFe2O4. The enhanced electrochemical activity of CuFe2O4-Fe2O3 composite is attributed to the synergistic effect which is responsible for redox coupling between Cu2+ and Fe3+ that has never been achieved by single component before.

Preparation of novel oxidized mesoporous carbon with excellent adsorption performance for removal of malachite green and lead ion

NASA Astrophysics Data System (ADS)

Zhang, Xialan; Lin, Qilang; Luo, Shiyuan; Ruan, Kezhao; Peng, Kaiping

2018-06-01

An oxidized mesoporous carbon (OMC) with fluffy structure was fabricated from the mixture of petroleum asphalt and aluminum isopropoxide, and its structures were characterized by FESEM, TEM, BET, TG, XPS and FT-IR. In addition, bath absorption experiments for malachite green (MG) and lead ion (Pb2+) were carried out to explore the effects of pH, initial concentration, contact time and temperature on its absorption process. Results show that the OMC prepared has a fluffy ultrathin-wall structure with narrow pore size distribution and rich oxygen-containing groups. It exhibits excellent absorption performance for the removal of MG as well as Pb2+, as indicated by that its maximum adsorption capacity is 963.1 mg g-1 for MG and 198.6 mg g-1 for Pb2+. The absorption experimental data are all fitted well with pseudo-second-order model and Frendlich isotherm, respectively. More importantly, the OMC still maintains relatively high adsorption capacity after five cycles.

High electrochemical capacitor performance of oxygen and nitrogen enriched activated carbon derived from the pyrolysis and activation of squid gladius chitin

NASA Astrophysics Data System (ADS)

Raj, C. Justin; Rajesh, Murugesan; Manikandan, Ramu; Yu, Kook Hyun; Anusha, J. R.; Ahn, Jun Hwan; Kim, Dong-Won; Park, Sang Yeup; Kim, Byung Chul

2018-05-01

Activated carbon containing nitrogen functionalities exhibits excellent electrochemical property which is more interesting for several renewable energy storage and catalytic applications. Here, we report the synthesis of microporous oxygen and nitrogen doped activated carbon utilizing chitin from the gladius of squid fish. The activated carbon has large surface area of 1129 m2 g-1 with microporous network and possess ∼4.04% of nitrogen content in the form of pyridinic/pyrrolic-N, graphitic-N and N-oxide groups along with oxygen and carbon species. The microporous oxygen/nitrogen doped activated carbon is utilize for the fabrication of aqueous and flexible supercapacitor electrodes, which presents excellent electrochemical performance with maximum specific capacitance of 204 Fg-1 in 1 M H2SO4 electrolyte and 197 Fg-1 as a flexible supercapacitor. Moreover, the device displays 100% of specific capacitance retention after 25,000 subsequent charge/discharge cycles in 1 M H2SO4 electrolyte.

A water-responsive shape memory ionomer with permanent shape reconfiguration ability

NASA Astrophysics Data System (ADS)

Bai, Yongkang; Zhang, Jiwen; Tian, Ran; Chen, Xin

2018-04-01

In this work, a water-responsive shape memory ionomer with high toughness was fabricated by cross-linking hyaluronic acid sodium (HAS) and polyvinyl alcohol (PVA) through coordination interactions. The strong Fe3+-carboxyl (from HAS) coordination interactions served as main physical cross-linking points for the performance of water-responsive shape memory, which associated with the flexibility of PVA chain producing excellent mechanical properties of this ionomer. The optimized ionomer was not only able to recover to its original shape within just 22 s by exposing to water, but exhibited high tensile strength up to 35.4 MPa and 4 times higher tractility than the ionomer without PVA. Moreover, the ionomers can be repeatedly programed to various new permanent shapes on demand due to the reversible physical interactions, which still performed complete and fast geometric recovery under stimuli even after 4 cycles of reprograming with 3 different shapes. The excellent shape memory and strong mechanical behaviors make our ionomers significant and promising smart materials for variety of applications.

Cellulose acetate-based SiO2/TiO2 hybrid microsphere composite aerogel films for water-in-oil emulsion separation

NASA Astrophysics Data System (ADS)

Yang, Xue; Ma, Jianjun; Ling, Jing; Li, Na; Wang, Di; Yue, Fan; Xu, Shimei

2018-03-01

The cellulose acetate (CA)/SiO2-TiO2 hybrid microsphere composite aerogel films were successfully fabricated via water vapor-induced phase inversion of CA solution and simultaneous hydrolysis/condensation of 3-aminopropyltrimethoxysilane (APTMS) and tetrabutyl titanate (TBT) at room temperature. Micro-nano hierarchical structure was constructed on the surface of the film. The film could separate nano-sized surfactant-stabilized water-in-oil emulsions only under gravity. The flux of the film for the emulsion separation was up to 667 L m-2 h-1, while the separation efficiency was up to 99.99 wt%. Meanwhile, the film exhibited excellent stability during multiple cycles. Moreover, the film performed excellent photo-degradation performance under UV light due to the photocatalytic ability of TiO2. Facile preparation, good separation and potential biodegradation maked the CA/SiO2-TiO2 hybrid microsphere composite aerogel films a candidate in oil/water separation application.

Large-scale synthesis of reduced graphene oxides with uniformly coated polyaniline for supercapacitor applications.

PubMed

Salunkhe, Rahul R; Hsu, Shao-Hui; Wu, Kevin C W; Yamauchi, Yusuke

2014-06-01

We report an effective route for the preparation of layered reduced graphene oxide (rGO) with uniformly coated polyaniline (PANI) layers. These nanocomposites are synthesized by chemical oxidative polymerization of aniline monomer in the presence of layered rGO. SEM, TEM, X-ray photoelectron spectroscopy (XPS), FTIR, and Raman spectroscopy analysis results demonstrated that reduced graphene oxide-polyaniline (rGO-PANI) nanocomposites are successfully synthesized. Because of synergistic effects, rGO-PANI nanocomposites prepared by this approach exhibit excellent capacitive performance with a high specific capacitance of 286 F g(-1) and high cycle reversibility of 94 % after 2000 cycles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

O3-type Na(Mn₀.₂₅Fe₀.₂₅Co₀.₂₅Ni₀.₂₅)O₂: a quaternary layered cathode compound for rechargeable Na ion batteries

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

Li, Xi; Zhou, Yong-Ning; Wu, Di

2014-12-01

We report a new layered Na(Mn₀.₂₅Fe₀.₂₅Co₀.₂₅Ni₀.₂₅)O₂ compound with O3 oxygen stacking. It delivers 180 mAh/g initial discharge capacity and 578 Wh/kg specific energy density with good cycling capability at high cutoff voltage. In situ X-ray diffraction (XRD) shows a reversible structure evolution of O3-P3-O3'-O3'' upon Na de-intercalation. The excellent capacity and cycling performance at high cutoff voltage make it an important model system for studying the general issue of capacity fading in layered Na cathode compounds.

Silk-regulated hierarchical hollow magnetite/carbon nanocomposite spheroids for lithium-ion battery anodes.

PubMed

Sheng, Weiqin; Zhu, Guobin; Kaplan, David L; Cao, Chuanbao; Zhu, Hesun; Lu, Qiang

2015-03-20

Hierarchical olive-like structured carbon-Fe3O4 nanocomposite particles composed of a hollow interior and a carbon coated surface are prepared by a facile, silk protein-assisted hydrothermal method. Silk nanofibers as templates and carbon precursors first regulate the formation of hollow Fe2O3 microspheres and then they are converted into carbon by a reduction process into Fe3O4. This process significantly simplifies the fabrication and carbon coating processes to form complex hollow structures. When tested as anode materials for lithium-ion batteries, these hollow carbon-coated particles exhibit high capacity (900 mAh g(-1)), excellent cycle stability (180 cycles) and rate performance due to their unique hierarchical hollow structure and carbon coating.

Facile synthesis of Mesoporouscobalt Hexacyanoferrate Nanocubes for High-Performance Supercapacitors

PubMed Central

2017-01-01

Mesoporous cobalt hexacyanoferrate nanocubes (meso–CoHCF) were prepared for the first time through a facile sacrificial template method. The CoHCF mesostructures possess a high specific surface area of 548.5 m2·g−1 and a large amount of mesopores, which enable fast mass transport of electrolyte and abundant energy storage sites. When evaluated as supercapacitor materials, the meso–CoHCF materials exhibit a high specific capacitance of 285 F·g−1, good rate capability and long cycle life with capacitance retention of 92.9% after 3000 cycles in Na2SO4 aqueous electrolyte. The excellent electrochemical properties demonstrate the rational preparation of mesoporous prussian blue and its analogues for energy storage applications. PMID:28825671

Zeolite-Templated Mesoporous Silicon Particles for Advanced Lithium-Ion Battery Anodes.

PubMed

Kim, Nahyeon; Park, Hyejeong; Yoon, Naeun; Lee, Jung Kyoo

2018-04-24

For the practical use of high-capacity silicon anodes in high-energy lithium-based batteries, key issues arising from the large volume change of silicon during cycling must be addressed by the facile structural design of silicon. Herein, we discuss the zeolite-templated magnesiothermic reduction synthesis of mesoporous silicon (mpSi) (mpSi-Y, -B, and -Z derived from commercial zeolite Y, Beta, and ZSM-5, respectively) microparticles having large pore volume (0.4-0.5 cm 3 /g), wide open pore size (19-31 nm), and small primary silicon particles (20-35 nm). With these appealing mpSi particle structural features, a series of mpSi/C composites exhibit outstanding performance including excellent cycling stabilities for 500 cycles, high specific and volumetric capacities (1100-1700 mAh g -1 and 640-1000 mAh cm -3 at 100 mA g -1 ), high Coulombic efficiencies (approximately 100%), and remarkable rate capabilities, whereas conventional silicon nanoparticles (SiNP)/C demonstrate limited cycle life. These enhanced electrochemical responses of mpSi/C composites are further manifested by low impedance build-up, high Li ion diffusion rate, and small electrode thickness changes after cycling compared with those of SiNP/C composite. In addition to the outstanding electrochemical properties, the low-cost materials and high-yield processing make the mpSi/C composites attractive candidates for high-performance and high-energy Li-ion battery anodes.

Free-Standing Hybrid Graphene Paper Encapsulating Nanostructures for High Cycle-Life Supercapacitors.

PubMed

Jiao, Xinyan; Hao, Qingli; Xia, Xifeng; Lei, Wu; Ouyang, Yu; Ye, Haitao; Mandler, Daniel

2018-03-09

The incorporation of spacers between graphene sheets has been investigated as an effective method to improve the electrochemical performance of graphene papers (GPs) for supercapacitors. Here, we report the design of free-standing GP@NiO and GP@Ni hybrid GPs in which NiO nanoclusters and Ni nanoparticles are encapsulated into graphene sheets through electrostatic assembly and subsequent vacuum filtration. The encapsulated NiO nanoclusters and Ni nanoparticles can mitigate the restacking of graphene sheets, providing sufficient spaces for high-speed ion diffusion and electron transport. In addition, the spacers strongly bind to graphene sheets, which can efficiently improve the electrochemical stability. Therefore, at a current density of 0.5 A g -1 , the GP@NiO and GP@Ni electrodes exhibit higher specific capacitances of 306.9 and 246.1 F g -1 than the GP electrode (185.7 F g -1 ). The GP@NiO and GP@Ni electrodes exhibit capacitance retention of 98.7 % and 95.6 % after 10000 cycles, demonstrating an outstanding cycling stability. Additionally, the GP@NiO∥GP@Ni delivers excellent cycling stability (93.7 % after 10 000 cycles) and high energy density. These free-standing encapsulated hybrid GPs have great potential as electrode for high-performance supercapacitors. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Scalable synthesis of Fe₃O₄ nanoparticles anchored on graphene as a high-performance anode for lithium ion batteries

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

Dong, Yu Cheng; Center of Super-Diamond and Advanced Films; Ma, Ru Guang

2013-05-01

We report a scalable strategy to synthesize Fe₃O₄/graphene nanocomposites as a high-performance anode material for lithium ion batteries. In this study, ferric citrate is used as precursor to prepare Fe₃O₄ nanoparticles without introducing additional reducing agent; furthermore and show that such Fe₃O₄ nanoparticles can be anchored on graphene sheets which attributed to multifunctional group effect of citrate. Electrochemical characterization of the Fe₃O₄/graphene nanocomposites exhibit large reversible capacity (~1347 mA h g⁻¹ at a current density of 0.2 C up to 100 cycles, and subsequent capacity of ~619 mA h g⁻¹ at a current density of 2 C up to 200more » cycles), as well as high coulombic efficiency (~97%), excellent rate capability, and good cyclic stability. High resolution transmission electron microscopy confirms that Fe₃O₄ nanoparticles, with a size of ~4–16 nm are densely anchored on thin graphene sheets, resulting in large synergetic effects between Fe₃O₄ nanoparticles and graphene sheets with high electrochemical performance. - Graphical abstract: The reduction of Fe³⁺ to Fe²⁺ and the deposition of Fe₃O₄ on graphene sheets occur simultaneously using citrate function as reductant and anchor agent in this reaction process. Highlights: • Fe₃O₄/graphene composites are synthesized directly from graphene and C₆H₅FeO₇. • The citrate function as reductant and anchor agent in this reaction process. • The resulting Fe₃O₄ particles (~4–16 nm) are densely anchored on graphene sheets. • The prepared Fe₃O₄/graphene composites exhibit excellent electrochemical performance.« less

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.

Effect of Co addition on the performance and structure of V/ZrCe catalyst for simultaneous removal of NO and Hg0 in simulated flue gas

NASA Astrophysics Data System (ADS)

Zhao, Lingkui; Li, Caiting; Du, Xueyu; Zeng, Guangming; Gao, Lei; Zhai, Yunbo; Wang, Teng; Zhang, Junyi

2018-04-01

The effect of CoOx addition on the performance and structure of V2O5/ZrO2-CeO2 catalyst for simultaneous removal of NO and Hg0 in simulated flue gas was investigated by various methods including SEM, BET, XRD, XPS, H2-TPR and FT-IR. It was found that the introduction of CoOx not only greatly enhanced the redox properties of catalysts, but also increased the catalytic performance for simultaneous removal of NO and Hg0. The CoOx-modified V2O5/ZrO2-CeO2 catalyst displayed excellent catalytic activity for NO conversion (89.6%) and Hg0 oxidation (88.9%) at 250 °C under SCR atmosphere. The synergistic effect among vanadium, cobalt, and the ZrCe support could induce oxygen vacancies formation and promote oxygen mobility via charge transfer. Besides, CoOx could assist vanadium species in rapidly changing the valence by the redox cycle of V5+ + Co2+ ↔ V4+ + Co3+. All the above features contribute to the excellent catalytic performance through CoOx addition.

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.

Biomass-Derived Nitrogen-Doped Carbon Nanofiber Network: A Facile Template for Decoration of Ultrathin Nickel-Cobalt Layered Double Hydroxide Nanosheets as High-Performance Asymmetric Supercapacitor Electrode.

PubMed

Lai, Feili; Miao, Yue-E; Zuo, Lizeng; Lu, Hengyi; Huang, Yunpeng; Liu, Tianxi

2016-06-01

The development of biomass-based energy storage devices is an emerging trend to reduce the ever-increasing consumption of non-renewable resources. Here, nitrogen-doped carbonized bacterial cellulose (CBC-N) nanofibers are obtained by one-step carbonization of polyaniline coated bacterial cellulose (BC) nanofibers, which not only display excellent capacitive performance as the supercapacitor electrode, but also act as 3D bio-template for further deposition of ultrathin nickel-cobalt layered double hydroxide (Ni-Co LDH) nanosheets. The as-obtained CBC-N@LDH composite electrodes exhibit significantly enhanced specific capacitance (1949.5 F g(-1) at a discharge current density of 1 A g(-1) , based on active materials), high capacitance retention of 54.7% even at a high discharge current density of 10 A g(-1) and excellent cycling stability of 74.4% retention after 5000 cycles. Furthermore, asymmetric supercapacitors (ASCs) are constructed using CBC-N@LDH composites as positive electrode materials and CBC-N nanofibers as negative electrode materials. By virtue of the intrinsic pseudocapacitive characteristics of CBC-N@LDH composites and 3D nitrogen-doped carbon nanofiber networks, the developed ASC exhibits high energy density of 36.3 Wh kg(-1) at the power density of 800.2 W kg(-1) . Therefore, this work presents a novel protocol for the large-scale production of biomass-derived high-performance electrode materials in practical supercapacitor applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Monolithic All-Phosphate Solid-State Lithium-Ion Battery with Improved Interfacial Compatibility.

PubMed

Yu, Shicheng; Mertens, Andreas; Tempel, Hermann; Schierholz, Roland; Kungl, Hans; Eichel, Rüdiger-A

2018-06-22

High interfacial resistance between solid electrolyte and electrode of ceramic all-solid-state batteries is a major reason for the reduced performance of these batteries. A solid-state battery using a monolithic all-phosphate concept based on screen printed thick LiTi 2 (PO 4 ) 3 anode and Li 3 V 2 (PO 4 ) 3 cathode composite layers on a densely sintered Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 solid electrolyte has been realized with competitive cycling performance. The choice of materials was primarily based on the (electro-)chemical and mechanical matching of the components instead of solely focusing on high-performance of individual components. Thus, the battery utilized a phosphate backbone in combination with tailored morphology of the electrode materials to ensure good interfacial matching for a durable mechanical stability. Moreover, the operating voltage range of the active materials matches with the intrinsic electrochemical window of the electrolyte which resulted in high electrochemical stability. A highly competitive discharge capacity of 63.5 mAh g -1 at 0.39 C after 500 cycles, corresponding to 84% of the initial discharge capacity, was achieved. The analysis of interfacial charge transfer kinetics confirmed the structural and electrical properties of the electrodes and their interfaces with the electrolyte, as evidenced by the excellent cycling performance of the all-phosphate solid-state battery. These interfaces have been studied via impedance analysis with subsequent distribution of relaxation times analysis. Moreover, the prepared solid-state battery could be processed and operated in air atmosphere owing to the low oxygen sensitivity of the phosphate materials. The analysis of electrolyte/electrode interfaces after cycling demonstrates that the interfaces remained stable during cycling.

Facile synthesis of a mesoporous Co3O4 network for Li-storage via thermal decomposition of an amorphous metal complex.

PubMed

Wen, Wei; Wu, Jin-Ming; Cao, Min-Hua

2014-11-07

A facile strategy is developed for mass fabrication of porous Co3O4 networks via the thermal decomposition of an amorphous cobalt-based complex. At a low mass loading, the achieved porous Co3O4 network exhibits excellent performance for lithium storage, which has a high capacity of 587 mA h g(-1) after 500 cycles at a current density of 1000 mA g(-1).

Sales Training for Army Recruiter Success: Sales Strategies and Skills Used by Excellent U. S. Army Recruiters

DTIC Science & Technology

1987-11-01

Army recruiters. Neurolinguistic programming (NLP) was used as the protocol for modeling performance and acquiring information on the communication...kills -Linguistic pattern~ Sales cycle, Communica tion s trategies Mode-H.R-g. Sales skills, {:( ~Expert kn0\\vlc dge1 ’ Neurolinguist ic~ Sales...describe s a program of r esearch on the communicat ion st rate - gies a nd skills use d by excellen t Army r ecrui t e rs. Information to be used to

Design to Cost and Life Cycle Cost.

DTIC Science & Technology

1980-07-01

The data are also based on a sample of reporting squadrons. Though the VAMOSC MS offers an excellent capability to deal with design-related issues...levels as predictions in the early design phase of a program. Figure 4 presents sample FY-78 costs from the VAMOSC MS report. The costs are on a cost...equlipmlent before attachlmenlt to adjacent sectionls. Ibis allows tile work tol be performed within thC reachl of tile most1 efficient equipment and w4ithl

Reconstruction of Mini-Hollow Polyhedron Mn2O3 Derived from MOFs as a High-Performance Lithium Anode Material.

PubMed

Cao, Kangzhe; Jiao, Lifang; Xu, Hang; Liu, Huiqiao; Kang, Hongyan; Zhao, Yan; Liu, Yongchang; Wang, Yijing; Yuan, Huatang

2016-03-01

A mini-hollow polyhedron Mn 2 O 3 is used as the anode material for lithium-ion batteries. Benefiting from the small interior cavity and intrinsic nanosize effect, a stable reconstructed hierarchical nanostructure is formed. It has excellent energy storage properties, exhibiting a capacity of 760 mAh g -1 at 2 A g -1 after 1000 cycles. This finding offers a new perspective for the design of electrodes with large energy storage.

Facile preparation of MnO2 nanorods and evaluation of their supercapacitive characteristics

NASA Astrophysics Data System (ADS)

Aghazadeh, Mustafa; Asadi, Maryam; Maragheh, Mohammad Ghannadi; Ganjali, Mohammad Reza; Norouzi, Parviz; Faridbod, Farnoush

2016-02-01

The first time pulsed base (OH-) electrogeneration to the cathodic electrodeposition of MnO2 in nitrate bath was applied and MnO2 nanorods were obtained. The deposition experiments were performed under a pulse current mode with typical on-times and off-times (ton = 10 ms and toff = 50 ms) and a peak current density of 2 mA cm-2 (Ia = 2 mA cm-2). The structural characterization with XRD and FTIR revealed that the prepared MnO2 is composed of both α and γ phases. Morphological evaluations through SEM and TEM revealed that the prepared MnO2 contains nanorods of relative uniform structures (with an average diameter of 50 nm). The electrochemical measurements through cyclic voltammetry and charge-discharge techniques revealed that the prepared MnO2 nanostructures reveal an excellent capacitive behavior with specific capacitance values of 242, 167 and 98 F g-1 under the applied current densities of 2, 5 and 10 A g-1, respectively. Also, excellent long-term cycling stabilities of 94.8%, 89.1%, and 76.5% were observed after 1000 charge-discharge cycles at the current densities of 2, 5 and 10 A g-1.

Carbon-supported, selenium-modified ruthenium-molybdenum catalysts for oxygen reduction in acidic media.

PubMed

Guinel, Maxime J-F; Bonakdarpour, Arman; Wang, Biao; Babu, Panakkattu K; Ernst, Frank; Ramaswamy, Nagappan; Mukerjee, Sanjeev; Wieckowski, Andrzej

2009-07-20

The stability and oxygen reduction activity of two carbon-supported catalyst materials are reported. The catalysts, Se/Ru and Se/(Ru-Mo), were prepared by using a chemical reduction method. The catalyst nanoparticles were evenly dispersed onto globular amorphous carbon supports, and their average size was ca. 2.4 nm. Thermal treatment at 500 °C for 2 h in an inert argon atmosphere resulted in coarsening of the nanoparticles, and also in some decrease of their activity. A gradual reduction of activity was also observed for Se/Ru during potential-cycle experiments. However, the incorporation of small amounts of Mo into the Se/Ru catalysts considerably improved the stability of the catalyst against dissolution. The Mo-containing samples showed excellent oxygen reduction activities even after cycling the potential 1000 times between 0.7 and 0.9 V. Furthermore, they showed excellent fuel-cell behavior. The performance of the Se/Ru catalysts is greatly improved by the addition of small amounts of elemental Mo. Possible mechanisms responsible for the improvement of the activity are discussed. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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.

Highly stable pyridinium-functionalized cross-linked anion exchange membranes for all vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Zeng, L.; Zhao, T. S.; Wei, L.; Zeng, Y. K.; Zhang, Z. H.

2016-11-01

It has recently been demonstrated that the use of anion exchange membranes (AEMs) in vanadium redox flow batteries (VRFBs) can reduce the migration of vanadium ions through the membrane due to the Donnan exclusion effect among the positively charged functional groups and vanadium ions. However, AEMs are plagued by low chemical stability in harsh chemical environments. Here we propose and fabricate a pyridinium-functionalized cross-linked AEM for VRFBs. The pyridinium-functionalized bromomethylated poly (2,6-dimethyl-1,4-phenylene oxide) exhibits a superior chemical stability as a result of the strengthened internal cross-linking networks and the chemical inertness of the polymer backbone. Therefore, the membrane exhibits littler decay in a harsh environment for 20 days during the course of an ex situ immersion test. A cycling test also demonstrates that the VRFB assembled with the membrane enable to retain 80% of the initial discharge capacity over 537 cycles with a capacity decay rate of 0.037% cycle-1. Meanwhile, the membrane also shows a low vanadium permeability and a reasonably high conductivity in supporting electrolytes. Hence, all the measurements and performance tests reported in this work suggest that the membrane is a promising AEM for redox flow batteries to achieve excellent cycling stability and superior cell performance.

A novel durable double-conductive core-shell structure applying to the synthesis of silicon anode for lithium ion batteries

NASA Astrophysics Data System (ADS)

Xing, Yan; Shen, Tong; Guo, Ting; Wang, Xiuli; Xia, Xinhui; Gu, Changdong; Tu, Jiangping

2018-04-01

Si/C composites are currently the most commercially viable next-generation lithium-ion battery anode materials due to their high specific capacity. However, there are still many obstacles need to be overcome such as short cycle life and poor conductivity. In this work, we design and successfully synthesis an excellent durable double-conductive core-shell structure p-Si-Ag/C composites. Interestingly, this well-designed structure offers remarkable conductivity (both internal and external) due to the introduction of silver particles and carbon layer. The carbon layer acts as a protective layer to maintain the integrity of the structure as well as avoids the direct contact of silicon with electrolyte. As a result, the durable double-conductive core-shell structure p-Si-Ag/C composites exhibit outstanding cycling stability of roughly 1000 mAh g-1 after 200 cycles at a current density of 0.2 A g-1 and retain 765 mAh g-1 even at a high current density of 2 A g-1, indicating a great improvement in electrochemical performance compared with traditional silicon electrode. Our research results provide a novel pathway for production of high-performance Si-based anodes to extending the cycle life and specific capacity of commercial lithium ion batteries.

Web-structured graphitic carbon fiber felt as an interlayer for rechargeable lithium-sulfur batteries with highly improved cycling performance

NASA Astrophysics Data System (ADS)

Lee, Dong Kyu; Ahn, Chi Won; Jeon, Hwan-Jin

2017-08-01

Graphitic carbon fiber felt (GCFF) with a crystalline graphitic carbon structure was facilely prepared by a combination of electrospinning and graphitization (2800 °C heat treatment) and was used as an interlayer between the cathode and separator in Li-S batteries. This GCFF interlayer trapped the polysulfides on the cathode side and increased the utilization of sulfur by suppressing the shuttle phenomenon. Also, the GCFF was shown to be able to act as an upper current collector to reduce the charge-transfer resistance owing to the high crystallinity of the graphitic carbon fibers. The sulfur cathode with the GCFF interlayer showed a high specific initial discharge capacity of 1280.14 mAh g-1 and excellent cycling stability (1004.62 mAh g-1 after 100 cycles) at 0.2 C. Also, an image of the glass fiber (GF) separator on the anode side confirmed the presence of an SEI after 200 cycles, which apparently resulted from stable Li deposition on the Li metal because of the low or medium concentration of sulfur in the electrolyte solution. Our observations should contribute to elucidating the key features of complex three-dimensional carbon fabrics with crystalline graphitic structures that allow them, when inserted as interlayers, to markedly improve the performance of rechargeable batteries.

Carbon-shell-constrained silicon cluster derived from Al-Si alloy as long-cycling life lithium ion batteries anode

NASA Astrophysics Data System (ADS)

Su, Junming; Zhang, Congcong; Chen, Xiang; Liu, Siyang; Huang, Tao; Yu, Aishui

2018-03-01

Although silicon is the most promising anode material for Li-ion batteries, large volume expansion during lithiation and delithiation is the main obstacle limiting the commercial application of silicon anodes. There are two ways to alleviate volume expansion and prevent further pulverization of a Si anode: fabrication of a rational nanostructure possessing void spaces and uniform distribution of the conducting sites, without a good balance effect in mitigating the limiting factors and enhancing battery performance. In this paper, we propose a novel nanostructure - a carbon-shell-constrained Si cluster (Si/C shell) with both adequate void space and good distribution of electrical contact sites to guarantee homogeneous lithiation in the initial cycle. Benefiting from the ability to maintain electrical conductivity of the outer carbon shell, even after cluster fragmentation, the Si/C shell synthesized from low-cost commercial Al-Si alloy spheres can deliver 0.03% capacity loss from 100th to 1000th cycles at a current density of 1 A g-1. The Si/C shell sample with the dual functional structure mentioned above can also maintain its own nanostructure during cycling and deliver excellent rate performance. It is a concise and scalable strategy which can simplify the preparation of other alloy anode materials for Li-ion batteries.

Ultraconcentrated Sodium Bis(fluorosulfonyl)imide-Based Electrolytes for High-Performance Sodium Metal Batteries.

PubMed

Lee, Jaegi; Lee, Yongwon; Lee, Jeongmin; Lee, Sang-Min; Choi, Jeong-Hee; Kim, Hyungsub; Kwon, Mi-Sook; Kang, Kisuk; Lee, Kyu Tae; Choi, Nam-Soon

2017-02-01

We present an ultraconcentrated electrolyte composed of 5 M sodium bis(fluorosulfonyl)imide in 1,2-dimethoxyethane for Na metal anodes coupled with high-voltage cathodes. Using this electrolyte, a very high Coulombic efficiency of 99.3% at the 120th cycle for Na plating/stripping is obtained in Na/stainless steel (SS) cells with highly reduced corrosivity toward Na metal and high oxidation durability (over 4.9 V versus Na/Na + ) without corrosion of the aluminum cathode current collector. Importantly, the use of this ultraconcentrated electrolyte results in substantially improved rate capability in Na/SS cells and excellent cycling performance in Na/Na symmetric cells without the increase of polarization. Moreover, this ultraconcentrated electrolyte exhibits good compatibility with high-voltage Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ) and Na 0.7 (Fe 0.5 Mn 0.5 )O 2 cathodes charged to high voltages (>4.2 V versus Na/Na + ), resulting in outstanding cycling stability (high reversible capacity of 109 mAh g -1 over 300 cycles for the Na/Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ) cell) compared with the conventional dilute electrolyte, 1 M NaPF 6 in ethylene carbonate/propylene carbonate (5/5, v/v).

Formation of g-C3N4@Ni(OH)2 Honeycomb Nanostructure and Asymmetric Supercapacitor with High Energy and Power Density.

PubMed

Dong, Bitao; Li, Mingyan; Chen, Sheng; Ding, Dawei; Wei, Wei; Gao, Guoxin; Ding, Shujiang

2017-05-31

Nickel hydroxide (Ni(OH) 2 ) has been regarded as a potential next-generation electrode material for supercapacitor owing to its attractive high theoretical capacitance. However, practical application of Ni(OH) 2 is hindered by its lower cycling life. To overcome the inherent defects, herein we demonstrate a unique interconnected honeycomb structure of g-C 3 N 4 and Ni(OH) 2 synthesized by an environmentally friendly one-step method. In this work, g-C 3 N 4 has excellent chemical stability and supports a perpendicular charge-transporting direction in charge-discharge process, facilitating electron transportation along that direction. The as-prepared composite exhibits higher specific capacities (1768.7 F g -1 at 7 A g -1 and 2667 F g -1 at 3 mV s -1 , respectively) compared to Ni(OH) 2 aggregations (968.9 F g -1 at 7 A g -1 ) and g-C 3 N 4 (416.5 F g -1 at 7 A g -1 ), as well as better cycling performance (∼84% retentions after 4000 cycles). As asymmetric supercapacitor, g-C 3 N 4 @Ni(OH) 2 //graphene exhibits high capacitance (51 F g -1 ) and long cycle life (72% retentions after 8000 cycles). Moreover, high energy density of 43.1 Wh kg -1 and power density of 9126 W kg -1 has been achieved. This attractive performance reveals that g-C 3 N 4 @Ni(OH) 2 with honeycomb architecture could find potential application as an electrode material for high-performance supercapacitors.

Solid-State Thin-Film Supercapacitors with Ultrafast Charge/Discharge Based on N-Doped-Carbon-Tubes/Au-Nanoparticles-Doped-MnO2 Nanocomposites.

PubMed

Lv, Qiying; Wang, Shang; Sun, Hongyu; Luo, Jun; Xiao, Jian; Xiao, JunWu; Xiao, Fei; Wang, Shuai

2016-01-13

Although carbonaceous materials possess long cycle stability and high power density, their low-energy density greatly limits their applications. On the contrary, metal oxides are promising pseudocapacitive electrode materials for supercapacitors due to their high-energy density. Nevertheless, poor electrical conductivity of metal oxides constitutes a primary challenge that significantly limits their energy storage capacity. Here, an advanced integrated electrode for high-performance pseudocapacitors has been designed by growing N-doped-carbon-tubes/Au-nanoparticles-doped-MnO2 (NCTs/ANPDM) nanocomposite on carbon fabric. The excellent electrical conductivity and well-ordered tunnels of NCTs together with Au nanoparticles of the electrode cause low internal resistance, good ionic contact, and thus enhance redox reactions for high specific capacitance of pure MnO2 in aqueous electrolyte, even at high scan rates. A prototype solid-state thin-film symmetric supercapacitor (SSC) device based on NCTs/ANPDM exhibits large energy density (51 Wh/kg) and superior cycling performance (93% after 5000 cycles). In addition, the asymmetric supercapacitor (ASC) device assembled from NCTs/ANPDM and Fe2O3 nanorods demonstrates ultrafast charge/discharge (10 V/s), which is among the best reported for solid-state thin-film supercapacitors with both electrodes made of metal oxide electroactive materials. Moreover, its superior charge/discharge behavior is comparable to electrical double layer type supercapacitors. The ASC device also shows superior cycling performance (97% after 5000 cycles). The NCTs/ANPDM nanomaterial demonstrates great potential as a power source for energy storage devices.

Surface and interface engineering of anatase TiO2 anode for sodium-ion batteries through Al2O3 surface modification and wise electrolyte selection

NASA Astrophysics Data System (ADS)

Li, Tao; Gulzar, Umair; Bai, Xue; Monaco, Simone; Longoni, Gianluca; Prato, Mirko; Marras, Sergio; Dang, Zhiya; Capiglia, Claudio; Proietti Zaccaria, Remo

2018-04-01

In the present study, Al2O3 is utilized for the first time as coating agent on nanostructured anatase TiO2 in order to investigate its effect on sodium-ion batteries performance. Our results show that the Al2O3 coating, introduced by a facile two-step approach, provides beneficial effects to the TiO2-based anodes. However, the coated TiO2 still suffers of capacity fading upon cycling when using 1.0 M of NaClO4 in propylene carbonate (PC) as electrolyte. To address this issue, the influence of different electrolytes (NaClO4 salt in various solvents) is further studied. It is found that the modified TiO2 exhibits significant improvements in cycling performance using binary ethylene carbonate (EC) and PC solvent mixture without the need of the commonly used fluoroethylene carbonate (FEC) additive. Under the best configuration, our battery could deliver a high reversible capacity of 188.1 mAh g-1 at 0.1C after 50 cycles, good rate capability up to 5C, and remarkable long-term cycling stability at 1C rate for 650 cycles. This excellent performance can be ascribed to the synergistic effects of surface and interface engineering enabling the formation of a stable and highly ionic conductive interface layer in EC:PC based electrolyte which combines the native SEI film and an 'artificial' SEI layer of irreversibly formed Na-Al-O.

Hybrid lithium-ion capacitor with LiFePO4/AC composite cathode - Long term cycle life study, rate effect and charge sharing analysis

NASA Astrophysics Data System (ADS)

Shellikeri, A.; Yturriaga, S.; Zheng, J. S.; Cao, W.; Hagen, M.; Read, J. A.; Jow, T. R.; Zheng, J. P.

2018-07-01

Energy storage devices, which can combine the advantages of lithium-ion battery with that of electric double layer capacitor, are of prime interest. Recently, composite cathodes, which combine a battery material with capacitor material, have shown promise in enhancing life cycle and energy/power performances. Lithium-ion capacitor (LIC), with unique charge storage mechanism of combining a pre-lithiated battery anode with a capacitor cathode, is one such device which has the potential to synergistically incorporate the composite cathode to enhance capacity and cycle life. We report here a hybrid LIC consisting of a lithium iron phosphate (LiFePO4-LFP)/Activated Carbon composite cathode in combination with a hard carbon anode, by integrating the cycle life and capacity enhancing strategies of a dry method of electrode fabrication, anode pre-lithiation and a 3:1 anode to cathode capacity ratio, demonstrating a long cycle life, while elaborating on the charge sharing between the faradaic and non-faradaic mechanism in the battery and capacitor materials, respectively in the composite cathode. An excellent cell capacity retention of 94% (1000 cycles at 1C) and 92% (100,000 cycles at 60C) were demonstrated, while retaining 78% (over 6000 cycles at 2.7C) and 67% (over 70,000 cycles at 43C) of the LFP capacity in the composite cathode.

Free-standing graphene films prepared via foam film method for great capacitive flexible supercapacitors

NASA Astrophysics Data System (ADS)

Zhu, Yucan; Ye, Xingke; Tang, Zhonghua; Wan, Zhongquan; Jia, Chunyang

2017-11-01

Recently, graphene films have always attracted attention due to their excellent characteristics in energy storage. In this work, a novel graphene oxide (GO) film with excellent mechanical properties, whose thickness was regulated simply via changing the concentration of the surfactant, was successfully prepared by foam film method. After chemical reduction, the reduced GO (rGO) films have excellent electrical conductivity of ∼172 S cm-1. Moreover, the supercapacitors based on the rGO films exhibit satisfied capacitive performance of ∼56 mF cm-2 at 0.2 mA cm-2 in 6 M KOH aqueous solution. Meanwhile, the flexible all solid state supercapacitors (FSSCs) based on the rGO films also show great volumetric capacitance of ∼2810 mF cm-3 at 12 mA cm-3 (∼1607 mF cm-3 at 613 mA cm-3) with polyvinyl alcohol-KOH gel electrolyte. Besides, after 10000 cycles and continuously bent to 180° for 300 times, the volumetric capacitance of the FSSC remains at 81.4% and 90.4% of its initial capacitance value, respectively. Therefore, the free-standing rGO films prepared via foam film method could be considered as promising electrode materials for high performance flexible supercapacitors.

Graphene oxide as a dual-function conductive binder for PEEK-derived microporous carbons in high performance supercapacitors

NASA Astrophysics Data System (ADS)

Kim, Christine H. J.; Zhang, Hongbo; Liu, Jie

2015-06-01

Microporous carbons (MPCs) are promising electrode materials for supercapacitors because of their high surface area and accessible pores. However, their low electrical conductivity and mechanical instability result in limited power density and poor cycle life. This work proposes a unique two-layered film made of polyetheretherketone-derived MPCs and reduced graphene oxide (rGO) as an electrode for supercapacitors. Electrochemical characterizations of films show that such a layered structure is more effective in increasing the accessibility of ions to the hydrophilic MPCs and establishing conductive paths through the rGO network than a simple mixed composite film. The two-layered structure increases the capacitance by ˜124% (237 F g-1) with excellent cycling stability (˜93% after 6000 cycles). More importantly, we demonstrate that such performance improvements result from an optimal balance between electrical conductivity and ion accessibility, which maximizes the synergistic effects of MPC and rGO. The MPCs, which are exposed to the surface, provide a highly accessible surface area for ion adsorption. The rGO serves a dual function as a conductive filler to increase the electrical conductivity and as a binder to interconnect individual MPC particles into a robust and flexible film. These findings provide a rational basis for the design of MPC-based electrodes in high performance supercapacitors.

Durable polydopamine-coated porous sulfur core-shell cathode for high performance lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

Deng, Yuanfu; Xu, Hui; Bai, Zhaowen; Huang, Baoling; Su, Jingyang; Chen, Guohua

2015-12-01

Lithium-sulfur batteries show fascinating potential for advanced energy system due to their high specific capacity, low-cost, and environmental benignity. However, their wide applications have been plagued by low coulombic efficiency, fast capacity fading and poor rate performance. Herein, a facile method for preparation of S@PDA (PDA = polydopamine) composites with core-shell structure and good electrochemical performance as well as the First-Principles calculations on the interactions of PDA and polysulfides are reported. Taking the advantages of the core-shell structure with porous sulfur core, the high mechanical flexibility of PDA for accommodating the volumetric variation during the discharge/charge processes, the good lithium ion conductivity and the strong chemical interactions between the nitrogen/oxygen atoms with lone electron pair and lithium polysulfides for alleviating their dissolution, the S@PDA composites exhibit high discharge capacities at different current densities (1048 and 869 mAh g-1 at 0.2 and 0.8 A g-1, respectively) and excellent capacity retention capability. A capacity decay as low as 0.021% per cycle and an average coulombic efficiency of 98.5% is observed over a long-term cycling of 890 cycles at 0.8 A g-1. The S@PDA electrode has great potential as a low-cost cathode in high energy Li-S batteries.

Rational design of hierarchical ZnO@Carbon nanoflower for high performance lithium ion battery anodes

NASA Astrophysics Data System (ADS)

liu, Huichao; Shi, Ludi; Li, Dongzhi; Yu, Jiali; Zhang, Han-Ming; Ullah, Shahid; Yang, Bo; Li, Cuihua; Zhu, Caizhen; Xu, Jian

2018-05-01

The rational structure design and strong interfacial bonding are crucially desired for high performance zinc oxide (ZnO)/carbon composite electrodes. In this context, micro-nano secondary structure design and strong dopamine coating strategies are adopted for the fabrication of flower-like ZnO/carbon (ZnO@C nanoflowers) composite electrodes. The results show the ZnO@C nanoflowers (2-6 μm) are assembled by hierarchical ZnO nanosheets (∼27 nm) and continuous carbon framework. The micro-nano secondary architecture can facilitate the penetration of electrolyte, shorten lithium ions diffusion length, and hinder the aggregation of the nanosheets. Moreover, the strong chemical interaction between ZnO and coating carbon layer via C-Zn bond improves structure stability as well as the electronic conductivity. As a synergistic result, when evaluated as lithium ion batteries (LIBs) anode, the ZnO@C nanoflower electrodes show high reversible capacity of ca. 1200 mA h g-1 at 0.1 A g-1 after 80 cycles. As well as good long-cycling stability (638 and 420 mA h g-1 at 1 and 5 A g-1 after 500 cycles, respectively) and excellent rate capability. Therefore, this rational design of ZnO@C nanoflowers electrode is a promising anode for high-performance LIBs.

Design and synthesis of hierarchical MnO2 nanospheres/carbon nanotubes/conducting polymer ternary composite for high performance electrochemical electrodes.

PubMed

Hou, Ye; Cheng, Yingwen; Hobson, Tyler; Liu, Jie

2010-07-14

For efficient use of metal oxides, such as MnO(2) and RuO(2), in pseudocapacitors and other electrochemical applications, the poor conductivity of the metal oxide is a major problem. To tackle the problem, we have designed a ternary nanocomposite film composed of metal oxide (MnO(2)), carbon nanotube (CNT), and conducting polymer (CP). Each component in the MnO(2)/CNT/CP film provides unique and critical function to achieve optimized electrochemical properties. The electrochemical performance of the film is evaluated by cyclic voltammetry, and constant-current charge/discharge cycling techniques. Specific capacitance (SC) of the ternary composite electrode can reach 427 F/g. Even at high mass loading and high concentration of MnO(2) (60%), the film still showed SC value as high as 200 F/g. The electrode also exhibited excellent charge/discharge rate and good cycling stability, retaining over 99% of its initial charge after 1000 cycles. The results demonstrated that MnO(2) is effectively utilized with assistance of other components (fFWNTs and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) in the electrode. Such ternary composite is very promising for the next generation high performance electrochemical supercapacitors.

Cumulative effect of transition metals on nitrogen and fluorine co-doped graphite nanofibers: an efficient and highly durable non-precious metal catalyst for the oxygen reduction reaction.

PubMed

Peera, S Gouse; Arunchander, A; Sahu, A K

2016-08-14

Nitrogen and fluorine co-doped graphite nanofibers (N/F-GNF) and their cumulative effect with Fe and Co have been developed as an alternative non-precious metal catalyst for efficient oxygen reduction reaction (ORR) in acidic media. The synergistic effect between the doped hetero atoms and the co-ordinated Fe and Co towards ORR activity and durability of the catalyst is deeply investigated. A high ORR onset potential comparable with commercial Pt/C catalyst is observed with the Fe-Co/NF-GNF catalyst, which indicates that this catalyst is a potential alternative to Pt/C. A fivefold increase in mass activity is achieved by the Fe-Co/NF-GNF catalyst compared to the simple N/F-GNF catalyst, which endorses the significant role of transition metal atoms in enhancing ORR activity. The advanced Fe-Co/NF-GNF catalyst also exhibits complete tolerance to CH3OH and CO. The Fe-Co/NF-GNF catalyst also exhibits excellent durability towards the ORR with only a 10 mV negative shift in its half wave potential after a 10 000 repeated potential cycling test, whereas in the case of a commercial Pt/C catalyst there was an ∼110 mV negative shift under similar environmental conditions. More stringent corrosive test cycles were also performed by maintaining the cell as high as 1.4 V with a later decrease to 0.6 V vs. RHE for 300 cycles, which showed the excellent durability of the Fe-Co/NF-GNF catalyst in comparison with the Pt/C catalyst. XPS analysis of the Fe-Co/NF-GNF catalyst presents the ORR active chemical states of N (pyridinic-N and graphitic-N) and F (semi-ionic-F) and the co-ordinated sites of Fe and Co species with the dopants. The excellent performance and durability of the Fe-Co/NF-GNF catalyst is due to the synergistic effect between the hetero atoms dopants (N and F) and strong co-ordinating bonds of M-N-C, which protect the graphene layers around the metallic species and greatly mitigates the leaching of Co and Fe during the long term cycling test. The high activity and long term durability of the Fe-Co/NF-GNF catalyst make it a promising ORR electrocatalyst for the fuel cell cathode reaction.

Improving thermal and electrochemical performances of LiCoO{sub 2} cathode at high cut-off charge potentials by MF{sub 3} (M=Ce, Al) coating

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

Aboulaich, Abdelmaula, E-mail: a.aboulaich@managemgroup.com; Ouzaouit, Khalid; Faqir, Hakim

2016-01-15

Highlights: • Fluoride metal is successfully coated on the surface of LiCoO{sub 2}. • Easy and scalable method is adopted for the synthesis of coated-LiCoO{sub 2}. • Appropriate amount of AlF{sub 3} or CeF{sub 3} is beneficial to reduce cation disorder. • The electrochemical performances of coated LiCoO{sub 2} is significantly enhanced at higher potential (cycling efficiency and reversible capacity). • The coated cathode exhibits excellent thermal stability highlighted by calorimetric technique. - Abstract: Surface coating of LiCoO{sub 2} remained one of the efficient methods to enhance its electrochemical and thermal performances, especially at high cut-off potential. In this work,more » MF{sub 3} (M = Ce, Al) coated LiCoO{sub 2} was synthesized via co-precipitation method followed by a solid state reaction at 400 °C. The morphology and structure of the modified cathode material were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the fluoride compound MF{sub 3} is successfully coated on the surface of LiCoO{sub 2} cathode particles with an average layer thickness about 12 nm and 40 nm for AlF{sub 3} and CeF{sub 3}, respectively. The electrochemical tests show that the AlF{sub 3}-coating layer significantly enhances the cycling performance of LiCoO{sub 2} cathode material, even at high cut-off potential. While the bare LiCoO{sub 2} cathode displays fast fading at 4.6 V vs. Li{sup +}/Li cutoff potential, the surface-modified electrode exhibits the great capacity of 160 mAh g{sup −1} with excellent capacity retention on several cycles. We concluded that the electrochemical and the thermal enhancement at high potential are ascribed to the presence of MF{sub 3} coating layer which prevent the side reaction during the charge discharge process, alleviate the attack by the acidic electrolyte and reduce the damage of electrode structure.« less

H-TiO(2) @MnO(2) //H-TiO(2) @C core-shell nanowires for high performance and flexible asymmetric supercapacitors.

PubMed

Lu, Xihong; Yu, Minghao; Wang, Gongming; Zhai, Teng; Xie, Shilei; Ling, Yichuan; Tong, Yexiang; Li, Yat

2013-01-11

A flexible solid-state asymmetric supercapacitor device with H-TiO(2) @MnO(2) core-shell NWs as the positive electrode and H-TiO(2) @C core-shell NWs as the negative electrode is developed. This device operates in a 1.8 V voltage window and is able to deliver a high specific capacitance of 139.6 F g(-1) and maximum volumetric energy density of 0.30 mWh cm(-3) with excellent cycling performance and good flexibility. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Porous hollow Co₃O₄ with rhombic dodecahedral structures for high-performance supercapacitors.

PubMed

Zhang, Yi-Zhou; Wang, Yang; Xie, Ye-Lei; Cheng, Tao; Lai, Wen-Yong; Pang, Huan; Huang, Wei

2014-11-06

Porous hollow Co₃O₄ with rhombic dodecahedral structures were prepared by the calcination of ZIF-67 ([Co(mim)2; mim = 2-methylimidazolate]) rhombic dodecahedral microcrystals. A supercapacitor was successfully constructed by adopting the resulting porous hollow Co₃O₄ rhombic dodecahedral structure as the electrode material, which showed a large specific capacitance of 1100 F g(-1) and retained more than 95.1% of the specific capacitance after 6000 continuous charge-discharge cycles. The excellent capacitive properties and stability mark the porous hollow Co₃O₄ with the rhombic dodecahedral structure as one of the most promising electrode materials for high-performance supercapacitors.

Improvement on high rate performance of LiFePO4 cathodes using graphene as a conductive agent

NASA Astrophysics Data System (ADS)

Wei, Xufang; Guan, Yibiao; Zheng, Xiaohui; Zhu, Qizhen; Shen, Jinran; Qiao, Ning; Zhou, Shuqin; Xu, Bin

2018-05-01

In this work, the electrochemical properties of the LiFePO4 cathode using graphene as a conductive agent were revealed. Compared to the conventional LiFePO4 electrodes with carbon black as a conductive agent, the graphene sheets can establish a more effective conductive framework due to their layered structure and excellent electronic conductivity, leading to better electrochemical rate performance. Furthermore, the obverse of increasing graphene content is continued gains in high-rate performance of the LiFePO4 electrodes. The electrodes with 30 wt% graphene show high capacities up to 103.1 mA h g-1 and 68 mA h g-1 during discharging with extremely high rates of 30 C and 50 C, respectively. Besides, good cycling performance at high rate is also achieved. The electrodes with 30 wt% graphene display a capacity retention higher than 80% after 1000 cycles at 30 C. These results not only indicate that the graphene could be a promising candidate as a conductive agent, but also provide a new insight for designing LiFePO4 electrodes with brilliant high-rate performance via a simple method.

Coaxial CoMoO4 nanowire arrays with chemically integrated conductive coating for high-performance flexible all-solid-state asymmetric supercapacitors.

PubMed

Chen, Yaping; Liu, Borui; Liu, Qi; Wang, Jun; Li, Zhanshuang; Jing, Xiaoyan; Liu, Lianhe

2015-10-07

Flexible all-solid-state supercapacitors have offered promising applications as novel energy storage devices based on their merits, such as small size, low cost, light weight and high wearability for high-performance portable electronics. However, one major challenge to make flexible all-solid-state supercapacitors depends on the improvement of electrode materials with higher electrical conductivity properties and longer cycling stability. In this article, we put forward a simple strategy to in situ synthesize 1D CoMoO4 nanowires (NWs), using highly conductive CC and an electrically conductive PPy wrapping layer on CoMoO4 NW arrays for high performance electrode materials. The results show that the CoMoO4/PPy hybrid NW electrode exhibits a high areal specific capacitance of ca. 1.34 F cm(-2) at a current density of 2 mA cm(-2), which is remarkably better than the corresponding values for a pure CoMoO4 NW electrode of 0.7 F cm(-2). An excellent cycling performance of nanocomposites of up to 95.2% (ca. 1.12 F cm(-2)) is achieved after 2000 cycles compared to pristine CoMoO4 NWs. In addition, we fabricate flexible all-solid-state ASC which can be cycled reversibly in the voltage range of 0-1.7 V, and exhibits a maximum energy density of 104.7 W h kg(-1) (3.522 mW h cm(-3)), demonstrating great potential for practical applications in flexible energy storage electronics.

Analysis and optimisation of a mixed fluid cascade (MFC) process

NASA Astrophysics Data System (ADS)

Ding, He; Sun, Heng; Sun, Shoujun; Chen, Cheng

2017-04-01

A mixed fluid cascade (MFC) process that comprises three refrigeration cycles has great capacity for large-scale LNG production, which consumes a great amount of energy. Therefore, any performance enhancement of the liquefaction process will significantly reduce the energy consumption. The MFC process is simulated and analysed by use of proprietary software, Aspen HYSYS. The effect of feed gas pressure, LNG storage pressure, water-cooler outlet temperature, different pre-cooling regimes, liquefaction, and sub-cooling refrigerant composition on MFC performance are investigated and presented. The characteristics of its excellent numerical calculation ability and the user-friendly interface of MATLAB™ and powerful thermo-physical property package of Aspen HYSYS are combined. A genetic algorithm is then invoked to optimise the MFC process globally. After optimisation, the unit power consumption can be reduced to 4.655 kW h/kmol, or 4.366 kW h/kmol on condition that the compressor adiabatic efficiency is 80%, or 85%, respectively. Additionally, to improve the process further, with regards its thermodynamic efficiency, configuration optimisation is conducted for the MFC process and several configurations are established. By analysing heat transfer and thermodynamic performances, the configuration entailing a pre-cooling cycle with three pressure levels, liquefaction, and a sub-cooling cycle with one pressure level is identified as the most efficient and thus optimal: its unit power consumption is 4.205 kW h/kmol. Additionally, the mechanism responsible for the weak performance of the suggested liquefaction cycle configuration lies in the unbalanced distribution of cold energy in the liquefaction temperature range.

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.

Designing 3D highly ordered nanoporous CuO electrodes for high-performance asymmetric supercapacitors.

PubMed

Moosavifard, Seyyed E; El-Kady, Maher F; Rahmanifar, Mohammad S; Kaner, Richard B; Mousavi, Mir F

2015-03-04

The increasing demand for energy has triggered tremendous research efforts for the development of lightweight and durable energy storage devices. Herein, we report a simple, yet effective, strategy for high-performance supercapacitors by building three-dimensional pseudocapacitive CuO frameworks with highly ordered and interconnected bimodal nanopores, nanosized walls (∼4 nm) and large specific surface area of 149 m(2) g(-1). This interesting electrode structure plays a key role in providing facilitated ion transport, short ion and electron diffusion pathways and more active sites for electrochemical reactions. This electrode demonstrates excellent electrochemical performance with a specific capacitance of 431 F g(-1) (1.51 F cm(-2)) at 3.5 mA cm(-2) and retains over 70% of this capacitance when operated at an ultrafast rate of 70 mA cm(-2). When this highly ordered CuO electrode is assembled in an asymmetric cell with an activated carbon electrode, the as-fabricated device demonstrates remarkable performance with an energy density of 19.7 W h kg(-1), power density of 7 kW kg(-1), and excellent cycle life. This work presents a new platform for high-performance asymmetric supercapacitors for the next generation of portable electronics and electric vehicles.

Hydrogenated TiO 2@reduced graphene oxide sandwich-like nanosheets for high voltage supercapacitor applications

DOE PAGES

Pham, Viet Hung; Nguyen-Phan, Thuy-Duong; Tong, Xiao; ...

2017-10-09

Hydrogenated TiO 2 has recently attracted considerable attention as potential electrode materials for supercapacitors due to its abundance, low cost, high conductivity, remarkable rate capability, and outstanding long-term cycling stability. In this paper, we demonstrate the synthesis of hydrogenated TiO 2 nanoparticles anchored on reduced graphene oxide nanosheets (HTG) in the form of sandwich-like nanosheet composites. Further, we explored their implementation as electrode materials for high voltage, symmetric supercapacitors, operating in the voltage window of 0–1.8 V. The HTGs were prepared by a sol-gel method, followed by hydrogenation in the temperature range 300–500 °C. Of the prepared composites, HTG preparedmore » at 400 °C exhibited the largest specific capacitance of 51 F g -1 at the current density of 1.0 A g -1 and excellent rate capability with 82.5% capacitance retention as the current density increased 40-fold, from 0.5 to 20.0 A g -1. HTG's excellent rate capability was attributed to its sandwich-like nanostructure, in which ultrasmall hydrogenated TiO 2 nanoparticles densely anchored onto both surfaces of the two-dimensional reduced graphene oxide sheets. Moreover, HTG-based supercapacitors also exhibited long-term cycling stability with the retention over 80% of its initial capacitance after 10,000 cycles. Finally, these properties suggest that HTG is a promising electrode material for the scalable manufacture of high-performance supercapacitors.« less

High areal capacity, micrometer-scale amorphous Si film anode based on nanostructured Cu foil for Li-ion batteries

NASA Astrophysics Data System (ADS)

Si, Wenping; Sun, Xiaolei; Liu, Xianghong; Xi, Lixia; Jia, Yandong; Yan, Chenglin; Schmidt, Oliver G.

2014-12-01

We report a feasible design to fabricate micrometer-scale Si films deposited on nanostructured Cu foil as high areal capacity anodes for Li-ion batteries with excellent cycling performance. Nanostructured copper oxides are prepared by anodic oxidation of Cu foil in alkaline solution. The resultant copper oxide nanofibers function as matrix for thick Si films (1-2 μm) loading. Metallic Cu nanofibers are obtained by in-situ electrochemical reduction at low potentials, which work as electrical highways for fast electron transport and a reliable mechanical matrix to accommodate volume changes during lithium-silicon alloy/dealloy processes. The engineered thick Si film anode exhibit both high areal capacity (0.48 mAh cm-2 for 1 μm Si film and 0.6 mAh cm-2 for 2 μm Si film after 200 cycles at 0.225 mA cm-2) and excellent rate capability (0.52 mAh cm-2 at 1.05 mA cm-2 for 2 μm Si film). The 2 μm silicon film electrode is able to recover to the initial value of 1 mAh cm-2 when the current rate is set back to 0.15 mA cm-2 even after cycling at high current rates. The reported concept can be a general method for high-loading-film electrodes, which is industrial scalable and compatible with current battery manufacturing processes.

Construction of Hierarchical α-MnO2 Nanowires@Ultrathin δ-MnO2 Nanosheets Core-Shell Nanostructure with Excellent Cycling Stability for High-Power Asymmetric Supercapacitor Electrodes.

PubMed

Ma, Zhipeng; Shao, Guangjie; Fan, Yuqian; Wang, Guiling; Song, Jianjun; Shen, Dejiu

2016-04-13

Poor electrical conductivity and mechanical instability are two major obstacles to realizing high performance of MnO2 as pseudocapacitor material. The construction of unique hierarchical core-shell nanostructures, therefore, plays an important role in the efficient enhancement of the rate capacity and the stability of this material. We herein report the fabrication of a hierarchical α-MnO2 nanowires@ultrathin δ-MnO2 nanosheets core-shell nanostructure by adopting a facile and practical solution-phase technique. The novel hierarchical nanostructures are composed of ultrathin δ-MnO2 nanosheets with a few atomic layers growing well on the surface of the ultralong α-MnO2 nanowires. The first specific capacitance of hierarchical core-shell nanostructure reached 153.8 F g(-1) at the discharge current density of as high as 20 A g(-1), and the cycling stability is retained at 98.1% after 10,000 charge-discharge cycles, higher than those in the literature. The excellent rate capacity and stability of the hierarchical core-shell nanostructures can be attributed to the structural features of the two MnO2 crystals, in which a 1D α-MnO2 nanowire core provides a stable structural backbone and the ultrathin 2D δ-MnO2 nanosheet shell creates more reactive active sites. The synergistic effects of different dimensions also contribute to the superior rate capability.

Hydrogenated TiO 2@reduced graphene oxide sandwich-like nanosheets for high voltage supercapacitor applications

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

Pham, Viet Hung; Nguyen-Phan, Thuy-Duong; Tong, Xiao

Hydrogenated TiO 2 has recently attracted considerable attention as potential electrode materials for supercapacitors due to its abundance, low cost, high conductivity, remarkable rate capability, and outstanding long-term cycling stability. In this paper, we demonstrate the synthesis of hydrogenated TiO 2 nanoparticles anchored on reduced graphene oxide nanosheets (HTG) in the form of sandwich-like nanosheet composites. Further, we explored their implementation as electrode materials for high voltage, symmetric supercapacitors, operating in the voltage window of 0–1.8 V. The HTGs were prepared by a sol-gel method, followed by hydrogenation in the temperature range 300–500 °C. Of the prepared composites, HTG preparedmore » at 400 °C exhibited the largest specific capacitance of 51 F g -1 at the current density of 1.0 A g -1 and excellent rate capability with 82.5% capacitance retention as the current density increased 40-fold, from 0.5 to 20.0 A g -1. HTG's excellent rate capability was attributed to its sandwich-like nanostructure, in which ultrasmall hydrogenated TiO 2 nanoparticles densely anchored onto both surfaces of the two-dimensional reduced graphene oxide sheets. Moreover, HTG-based supercapacitors also exhibited long-term cycling stability with the retention over 80% of its initial capacitance after 10,000 cycles. Finally, these properties suggest that HTG is a promising electrode material for the scalable manufacture of high-performance supercapacitors.« less

Solvent-Free Synthesis of Uniform MOF Shell-Derived Carbon Confined SnO2 /Co Nanocubes for Highly Reversible Lithium Storage.

PubMed

He, Qiu; Liu, Jinshuai; Li, Zhaohuai; Li, Qi; Xu, Lin; Zhang, Baoxuan; Meng, Jiashen; Wu, Yuzhu; Mai, Liqiang

2017-10-01

Tin dioxide (SnO 2 ) has attracted much attention in lithium-ion batteries (LIBs) due to its abundant source, low cost, and high theoretical capacity. However, the large volume variation, irreversible conversion reaction limit its further practical application in next-generation LIBs. Here, a novel solvent-free approach to construct uniform metal-organic framework (MOF) shell-derived carbon confined SnO 2 /Co (SnO 2 /Co@C) nanocubes via a two-step heat treatment is developed. In particular, MOF-coated CoSnO 3 hollow nanocubes are for the first time synthesized as the intermediate product by an extremely simple thermal solid-phase reaction, which is further developed as a general strategy to successfully obtain other uniform MOF-coated metal oxides. The as-synthesized SnO 2 /Co@C nanocubes, when tested as LIB anodes, exhibit a highly reversible discharge capacity of 800 mAh g -1 after 100 cycles at 200 mA g -1 and excellent cycling stability with a retained capacity of 400 mAh g -1 after 1800 cycles at 5 A g -1 . The experimental analyses demonstrate that these excellent performances are mainly ascribed to the delicate structure and a synergistic effect between Co and SnO 2 . This facile synthetic approach will greatly contribute to the development of functional metal oxide-based and MOF-assisted nanostructures in many frontier applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dynamic evaluation of low-temperature metal-supported solid oxide fuel cell oriented to auxiliary power units

NASA Astrophysics Data System (ADS)

Wang, Zhenwei; Berghaus, Jörg Oberste; Yick, Sing; Decès-Petit, Cyrille; Qu, Wei; Hui, Rob; Maric, Radenka; Ghosh, Dave

A metal-supported solid oxide fuel cell (SOFC) composed of a Ni-Ce 0.8Sm 0.2O 2- δ (Ni-SDC) cermet anode and an SDC electrolyte was fabricated by suspension plasma spraying on a Hastelloy X substrate. The cathode, an Sm 0.5Sr 0.5CoO 3 (SSCo)-SDC composite, was screen-printed and fired in situ. The dynamic behaviour of the cell was measured while subjected to complete fuel shutoff and rapid start-up cycles, as typically encountered in auxiliary power units (APU) applications. A promising performance - with a maximum power density (MPD) of 0.176 W cm -2 at 600 °C - was achieved using humidified hydrogen as fuel and air as the oxidant. The cell also showed excellent resistance to oxidation at 600 °C during fuel shutoff, with only a slight drop in performance after reintroduction of the fuel. The Cr and Mn species in the Hastelloy X alloy appeared to be preferentially oxidized while the oxidation of nickel in the metallic substrate was temporarily alleviated. In rapid start-up cycles with a heating rate of 60 °C min -1, noticeable performance deterioration took place in the first two thermal cycles, and then continued at a much slower rate in subsequent cycles. A postmortem analysis of the cell suggested that the degradation was mainly due to the mismatch of the thermal expansion coefficient across the cathode/electrolyte interface.