Double-Sided Electrochromic Device Based on Metal-Organic Frameworks.

PubMed

Mjejri, Issam; Doherty, Cara M; Rubio-Martinez, Marta; Drisko, Glenna L; Rougier, Aline

2017-11-22

Devices displaying controllably tunable optical properties through an applied voltage are attractive for smart glass, mirrors, and displays. Electrochromic material development aims to decrease power consumption while increasing the variety of attainable colors, their brilliance, and their longevity. We report the first electrochromic device constructed from metal organic frameworks (MOFs). Two MOF films, HKUST-1 and ZnMOF-74, are assembled so that the oxidation of one corresponds to the reduction of the other, allowing the two sides of the device to simultaneously change color. These MOF films exhibit cycling stability unrivaled by other MOFs and a significant optical contrast in a lithium-based electrolyte. HKUST-1 reversibly changed from bright blue to light blue and ZnMOF-74 from yellow to brown. The electrochromic device associates the two MOF films via a PMMA-lithium based electrolyte membrane. The color-switching of these MOFs does not arise from an organic-linker redox reaction, signaling unexplored possibilities for electrochromic MOF-based materials.

Electrolyte for batteries with regenerative solid electrolyte interface

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

Xiao, Jie; Lu, Dongping; Shao, Yuyan

2017-08-01

An energy storage device comprising: an anode; and a solute-containing electrolyte composition wherein the solute concentration in the electrolyte composition is sufficiently high to form a regenerative solid electrolyte interface layer on a surface of the anode only during charging of the energy storage device, wherein the regenerative layer comprises at least one solute or solvated solute from the electrolyte composition.

Performance of carbon-carbon supercapacitors based on organic, aqueous and ionic liquid electrolytes

NASA Astrophysics Data System (ADS)

Lewandowski, Andrzej; Olejniczak, Angelika; Galinski, Maciej; Stepniak, Izabela

Properties of capacitors working with the same carbon electrodes (activated carbon cloth) and three types of electrolytes: aqueous, organic and ionic liquids were compared. Capacitors filled with ionic liquids worked at a potential difference of 3.5 V, their solutions in AN and PC were charged up to the potential difference of 3 V, classical organic systems to 2.5 V and aqueous to 1 V. Cyclic voltammetry, galvanostatic charging/discharging and impedance spectroscopy were used to characterize these capacitors. The highest specific energy was recorded for the device working with ionic liquids, while the highest power is characteristic for the device filled with aqueous H 2SO 4 electrolyte. Aqueous electrolytes led to energy density an order of magnitude lower in comparison to that characteristic of ionic liquids.

Quasi-solid state electrolytes for low-grade thermal energy harvesting using a cobalt redox couple.

PubMed

Taheri, Abuzar; MacFarlane, Douglas; Pozo-Gonzalo, Cristina; Pringle, Jennifer M

2018-06-06

Thermoelectrochemical cells, also known as thermocells, are electrochemical devices for the conversion of thermal energy directly to electricity. They are a promising method for harvesting low-grade waste heat from a variety of different natural and man-made sources. The development of solid or quasi-solid state electrolytes for thermocells could address the possible leakage problems of liquid electrolytes and make this technology more applicable for wearable devices. Here we report the gelation of an organic solvent-based electrolyte system containing a redox couple, for application in thermocell technologies. The effect of gelation of the liquid electrolyte, comprising a cobalt bipyridyl redox couple dissolved in 3-methoxypropionitrile (MPN), on the performance of thermocells was investigated. Polyvinylidene difluoride (PVDF) and poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) were used for gelation of the electrolyte, and the influence of the different polymers on the mechanical properties was studied. The Seebeck coefficient and diffusivity of the cobalt redox couple were measured in both liquid and gelled electrolytes and the effect of gelation on the thermocell performance is reported. Finally, the cell performance was further improved by optimising the redox couple concentration and the separation between the hot and cold electrode, and the stability of the device over 25 hours of operation is demonstrated. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Non-aqueous electrolytes for electrochemical cells

DOEpatents

Zhang, Zhengcheng; Dong, Jian; Amine, Khalil

2016-06-14

An electrolyte electrochemical device includes an anodic material and an electrolyte, the electrolyte including an organosilicon solvent, a salt, and a hybrid additiving having a first and a second compound, the hybrid additive configured to form a solid electrolyte interphase film on the anodic material upon application of a potential to the electrochemical device.

Thermally responsive polymer electrolytes for inherently safe electrochemical energy storage

NASA Astrophysics Data System (ADS)

Kelly, Jesse C.

Electrochemical double layer capacitors (EDLCs), supercapacitors and Li-ion batteries have emerged as premier candidates to meet the rising demands in energy storage; however, such systems are limited by thermal hazards, thermal runaway, fires and explosions, all of which become increasingly more dangerous in large-format devices. To prevent such scenarios, thermally-responsive polymer electrolytes (RPEs) that alter properties in electrochemical energy storage devices were designed and tested. These RPEs will be used to limit or halt device operation when temperatures increase beyond a predetermined threshold, therefore limiting further heating. The development of these responsive systems will offer an inherent safety mechanism in electrochemical energy storage devices, while preserving the performance, lifetimes, and versatility that large-format systems require. Initial work focused on the development of a model system that demonstrated the concept of RPEs in an electrochemical device. Aqueous electrolyte solutions of polymers exhibiting properties that change in response to temperature were developed for applications in EDLCs and supercapacitors. These "smart materials" provide a means to control electrochemical systems where polymer phase separation at high temperatures affects electrolyte properties and inhibits device performance. Aqueous RPEs were synthesized using N-isopropylacrylamide, which governs the thermal properties, and fractions of acrylic acid or vinyl sulfonic acids, which provide ions to the solution. The molecular properties of these aqueous RPEs, specifically the ionic composition, were shown to influence the temperature-dependent electrolyte properties and the extent to which these electrolytes control the energy storage characteristics of a supercapacitor device. Materials with high ionic content provided the highest room temperature conductivity and electrochemical activity; however, RPEs with low ionic content provided the highest "on-off" ratio in electrochemical activity at elevated temperatures. Overall, solution pH and conductivity were altered by an order of magnitude and device performance (ability to store charge) decreased by over 70%. After demonstration of a model responsive electrolyte in an aqueous system, ionic liquid (IL) based electrolytes were developed as a means of controlling the electrochemical performance in the non-aqueous environments that batteries, specifically Li-ion, require. Here, two systems were developed: (1) an electrolyte comprising poly(ethylene oxide) (PEO), the IL, [EMIM][BF4], and a lithium salt and (2) an electrolyte comprising poly(benzyl methacrylate) (PBzMA), the IL, [EMIM][TFSI], and a lithium salt. In each system, the polymer-IL phase separation inhibited device operation at elevated temperatures. For the PEO/IL electrolyte, the thermally induced liquid-liquid phase separation was shown to decrease the ionic conductivity, thereby affecting the concentration of ions at the electrode. Additionally, an increasing charge transfer resistance associated with the phase separated polymer coating the porous electrode was shown to limit electrochemical activity significantly. For the PBzMA/IL electrolyte, the solid-liquid phase separation did not show a change in conductivity, but did cause a drastic increase in charge transfer resistance, effectively shutting off Li-ion battery operation at high temperatures. Such responsive mixtures provide a transformative approach to regulating electrochemical processes, which is necessary to achieve inherently safe operation in large format energy storage with EDLCs, supercapacitors and Li-ion batteries.

Bio-sorbable, liquid electrolyte gated thin-film transistor based on a solution-processed zinc oxide layer.

PubMed

Singh, Mandeep; Palazzo, Gerardo; Romanazzi, Giuseppe; Suranna, Gian Paolo; Ditaranto, Nicoletta; Di Franco, Cinzia; Santacroce, Maria Vittoria; Mulla, Mohammad Yusuf; Magliulo, Maria; Manoli, Kyriaki; Torsi, Luisa

2014-01-01

Among the metal oxide semiconductors, ZnO has been widely investigated as a channel material in thin-film transistors (TFTs) due to its excellent electrical properties, optical transparency and simple fabrication via solution-processed techniques. Herein, we report a solution-processable ZnO-based thin-film transistor gated through a liquid electrolyte with an ionic strength comparable to that of a physiological fluid. The surface morphology and chemical composition of the ZnO films upon exposure to water and phosphate-buffered saline (PBS) are discussed in terms of the operation stability and electrical performance of the ZnO TFT devices. The improved device characteristics upon exposure to PBS are associated with the enhancement of the oxygen vacancies in the ZnO lattice due to Na(+) doping. Moreover, the dissolution kinetics of the ZnO thin film in a liquid electrolyte opens the possible applicability of these devices as an active element in "transient" implantable systems.

Solid lithium-ion electrolyte

DOEpatents

Zhang, Ji-Guang; Benson, David K.; Tracy, C. Edwin

1998-01-01

The present invention relates to the composition of a solid lithium-ion electrolyte based on the Li.sub.2 O--CeO.sub.2 --SiO.sub.2 system having good transparent characteristics and high ion conductivity suitable for uses in lithium batteries, electrochromic devices and other electrochemical applications.

A Comparison of Electrolytic Capacitors and Supercapacitors for Piezo-Based Energy Harvesting

DTIC Science & Technology

2013-07-01

A Comparison of Electrolytic Capacitors and Supercapacitors for Piezo-Based Energy Harvesting by Matthew H. Ervin, Carlos M. Pereira, John R...Capacitors and Supercapacitors for Piezo-Based Energy Harvesting Matthew H. Ervin Sensors and Electronic Devices Directorate, ARL Carlos M. Pereira... Supercapacitors for Piezo-Based Energy Harvesting 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Matthew H

Newly Elaborated Multipurpose Polymer Electrolyte Encompassing RTILs for Smart Energy-Efficient Devices.

PubMed

Nair, Jijeesh R; Porcarelli, Luca; Bella, Federico; Gerbaldi, Claudio

2015-06-17

Profoundly ion-conducting, self-standing, and tack-free ethylene oxide-based polymer electrolytes encompassing a room-temperature ionic liquid (RTIL) with specific amounts of lithium salt are successfully prepared via a rapid and easily upscalable process including a UV irradiation step. All prepared materials are thoroughly characterized in terms of their physical, chemical, and morphological properties and eventually galvanostatically cycled in lab-scale lithium batteries (LIBs) exploiting a novel direct polymerization procedure to get intimate electrode/electrolyte interfacial characteristics. The promising multipurpose characteristics of the newly elaborated materials are demonstrated by testing them in dye-sensitized solar cells (DSSCs), where the introduction of the iodine/iodide-based redox mediator in the polymer matrix assured the functioning of a lab-scale test cell with conversion efficiency exceeding 6% at 1 sun. The reported results enlighten the promising prospects of the material to be successfully implemented as stable, durable, and efficient electrolyte in next-generation energy conversion and storage devices.

Flexible thin-film battery based on solid-like ionic liquid-polymer electrolyte

NASA Astrophysics Data System (ADS)

Li, Qin; Ardebili, Haleh

2016-01-01

The development of high-performance flexible batteries is imperative for several contemporary applications including flexible electronics, wearable sensors and implantable medical devices. However, traditional organic liquid-based electrolytes are not ideal for flexible batteries due to their inherent safety and stability issues. In this study, a non-volatile, non-flammable and safe ionic liquid (IL)-based polymer electrolyte film with solid-like feature is fabricated and incorporated in a flexible lithium ion battery. The ionic liquid is 1-Ethyl-3-methylimidazolium dicyanamide (EMIMDCA) and the polymer is composed of poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP). The electrolyte exhibits good thermal stability (i.e. no weight loss up to 300 °C) and relatively high ionic conductivity (6 × 10-4 S cm-1). The flexible thin-film lithium ion battery based on solid-like electrolyte film is encapsulated using a thermal-lamination process and demonstrates excellent electrochemical performance, in both flat and bent configurations.

Solvothermal synthesis of gallium-indium-zinc-oxide nanoparticles for electrolyte-gated transistors.

PubMed

Santos, Lídia; Nunes, Daniela; Calmeiro, Tomás; Branquinho, Rita; Salgueiro, Daniela; Barquinha, Pedro; Pereira, Luís; Martins, Rodrigo; Fortunato, Elvira

2015-01-14

Solution-processed field-effect transistors are strategic building blocks when considering low-cost sustainable flexible electronics. Nevertheless, some challenges (e.g., processing temperature, reliability, reproducibility in large areas, and cost effectiveness) are requirements that must be surpassed in order to achieve high-performance transistors. The present work reports electrolyte-gated transistors using as channel layer gallium-indium-zinc-oxide nanoparticles produced by solvothermal synthesis combined with a solid-state electrolyte based on aqueous dispersions of vinyl acetate stabilized with cellulose derivatives, acrylic acid ester in styrene and lithium perchlorate. The devices fabricated using this approach display a ION/IOFF up to 1 × 10(6), threshold voltage (VTh) of 0.3-1.9 V, and mobility up to 1 cm(2)/(V s), as a function of gallium-indium-zinc-oxide ink formulation and two different annealing temperatures. These results validates the usage of electrolyte-gated transistors as a viable and promising alternative for nanoparticle based semiconductor devices as the electrolyte improves the interface and promotes a more efficient step coverage of the channel layer, reducing the operating voltage when compared with conventional dielectrics gating. Moreover, it is shown that by controlling the applied gate potential, the operation mechanism of the electrolyte-gated transistors can be modified from electric double layer to electrochemical doping.

Solid lithium-ion electrolyte

DOEpatents

Zhang, J.G.; Benson, D.K.; Tracy, C.E.

1998-02-10

The present invention relates to the composition of a solid lithium-ion electrolyte based on the Li{sub 2}O--CeO{sub 2}--SiO{sub 2} system having good transparent characteristics and high ion conductivity suitable for uses in lithium batteries, electrochromic devices and other electrochemical applications. 12 figs.

Printed environmentally friendly supercapacitors with ionic liquid electrolytes on paper

NASA Astrophysics Data System (ADS)

Pettersson, F.; Keskinen, J.; Remonen, T.; von Hertzen, L.; Jansson, E.; Tappura, K.; Zhang, Y.; Wilén, C.-E.; Österbacka, R.

2014-12-01

Environmentally friendly supercapacitors are fabricated using commercial grade aluminum coated paper as a substrate and symmetrical activated carbon electrodes as large area electrodes. Different choline chloride-based eutectic solvents are used as electrolyte. These are inexpensive, environmentally friendly and have a larger operating window compared to that of water electrolytes. As the entire device is printed and the materials used are inexpensive, both small- and large-area power sources can be fabricated to be used in cheap, disposable and recyclable devices. Supercapacitors with different eutectic solvents are measured using cyclic charge-discharge and impedance spectroscopy measurements and compared to one widely used and one "green" imidazolium ionic liquid; EMIM:TFSI and EcoEng 212™, respectively. A mixture of ethylene glycol and choline chloride, Glyceline™, show the highest capacitance and power densities of the electrolytes being tested, including the imidazolium alternatives.

Lithium-ion batteries having conformal solid electrolyte layers

DOEpatents

Kim, Gi-Heon; Jung, Yoon Seok

2014-05-27

Hybrid solid-liquid electrolyte lithium-ion battery devices are disclosed. Certain devices comprise anodes and cathodes conformally coated with an electron insulating and lithium ion conductive solid electrolyte layer.

Device for equalizing molten electrolyte content in a fuel cell stack

DOEpatents

Smith, J.L.

1985-12-23

A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

Device for equalizing molten electrolyte content in a fuel cell stack

DOEpatents

Smith, James L.

1987-01-01

A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

Self-Healable and Cold-Resistant Supercapacitor Based on a Multifunctional Hydrogel Electrolyte.

PubMed

Tao, Feng; Qin, Liming; Wang, Zhikui; Pan, Qinmin

2017-05-10

Excellent self-healability and cold resistance are attractive properties for a portable/wearable energy-storage device. However, achieving the features is fundamentally dependent on an intrinsically self-healable electrolyte with high ionic conduction at low temperature. Here we report such a hydrogel electrolyte comprising sodium alginate cross-linked by dynamic catechol-borate ester bonding. Since its dynamically cross-linked alginate network can tolerate high-content inorganic salts, the electrolyte possesses excellent healing efficiency/cyclability but also high ionic conduction at both room temperature and low temperature. A supercapacitor with the multifunctional hydrogel electrolyte completely restores its capacitive properties even after breaking/healing for 10 cycles without external stimulus. At a low temperature of -10 °C, the capacitor is even able to maintain at least 80% of its room-temperature capacitance. Our investigations offer a strategy to assemble self-healable and cold-resistant energy storage devices by using a multifunctional hydrogel electrolyte with rationally designed polymeric networks, which has potential application in portable/wearable electronics, intelligent apparel or flexible robot, and so on.

Optimizing Ionic Electrolytes for Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Fan, Xiaojuan; Hall, Sarah

2009-03-01

Dye-sensitized solar cells DSSCs provide next generation, low cost, and easy fabrication photovoltaic devices based on organic sensitizing molecules, polymer gel electrolyte, and metal oxide semiconductors. One of the key components is the solvent-free ionic liquid electrolyte that has low volatility and high stability. We report a rapid and low cost method to fabricate ionic polymer electrolyte used in DSSCs. Poly(ethylene oxide) (PEO) is blended with imidazolinium salt without any chemical solvent to form a gel electrolyte. Uniform and crack-free porous TiO2 thin films are sensitized by porphrine dye covered by the synthesized gel electrolyte. The fabricated DSSCs are more stable and potentially increase the photo-electricity conversion efficiency.

Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature.

PubMed

Lin, Xinrong; Chapman Varela, Jennifer; Grinstaff, Mark W

2016-12-20

The chemical instability of the traditional electrolyte remains a safety issue in widely used energy storage devices such as Li-ion batteries. Li-ion batteries for use in devices operating at elevated temperatures require thermally stable and non-flammable electrolytes. Ionic liquids (ILs), which are non-flammable, non-volatile, thermally stable molten salts, are an ideal replacement for flammable and low boiling point organic solvent electrolytes currently used today. We herein describe the procedures to: 1) synthesize mono- and di-phosphonium ionic liquids paired with chloride or bis(trifluoromethane)sulfonimide (TFSI) anions; 2) measure the thermal properties and stability of these ionic liquids by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA); 3) measure the electrochemical properties of the ionic liquids by cyclic voltammetry (CV); 4) prepare electrolytes containing lithium bis(trifluoromethane)sulfonamide; 5) measure the conductivity of the electrolytes as a function of temperature; 6) assemble a coin cell battery with two of the electrolytes along with a Li metal anode and LiCoO2 cathode; and 7) evaluate battery performance at 100 °C. We additionally describe the challenges in execution as well as the insights gained from performing these experiments.

Ultrathin Graphene-Protein Supercapacitors for Miniaturized Bioelectronics.

PubMed

Mosa, Islam M; Pattammattel, Ajith; Kadimisetty, Karteek; Pande, Paritosh; El-Kady, Maher F; Bishop, Gregory W; Novak, Marc; Kaner, Richard B; Basu, Ashis K; Kumar, Challa V; Rusling, James F

2017-09-06

Nearly all implantable bioelectronics are powered by bulky batteries which limit device miniaturization and lifespan. Moreover, batteries contain toxic materials and electrolytes that can be dangerous if leakage occurs. Herein, an approach to fabricate implantable protein-based bioelectrochemical capacitors (bECs) employing new nanocomposite heterostructures in which 2D reduced graphene oxide sheets are interlayered with chemically modified mammalian proteins, while utilizing biological fluids as electrolytes is described. This protein-modified reduced graphene oxide nanocomposite material shows no toxicity to mouse embryo fibroblasts and COS-7 cell cultures at a high concentration of 1600 μg mL -1 which is 160 times higher than those used in bECs, unlike the unmodified graphene oxide which caused toxic cell damage even at low doses of 10 μg mL -1 . The bEC devices are 1 μm thick, fully flexible, and have high energy density comparable to that of lithium thin film batteries. COS-7 cell culture is not affected by long-term exposure to encapsulated bECs over 4 d of continuous charge/discharge cycles. These bECs are unique, protein-based devices, use serum as electrolyte, and have the potential to power a new generation of long-life, miniaturized implantable devices.

A Polymer Electrolyte for Dye-Sensitized Solar Cells Based on a Poly(Polyvinylidenefluoride-Co-Hexafluoropropylene)/Hydroxypropyl Methyl Cellulose Blend

NASA Astrophysics Data System (ADS)

Won, Lee Ji; Kim, Jae Hong; Thogiti, Suresh

2018-05-01

A novel polymer blend electrolyte for dye-sensitized solar cells (DSSCs) was synthesized by quasi-solidifying a liquid-based electrolyte containing an iodide/triiodide redox couple and supporting salts with a mixture of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and indigenous hydroxypropyl methyl cellulose (HPMC). A high ionic conductivity of 8.8 × 10-4 S cm-1 was achieved after introducing 5 wt% of HPMC with respect to the weight of PVDH-HFP. DSSCs were fabricated using gel polymer blend electrolytes, and the J-V characteristics of the fabricated devices were analyzed. Under optimal conditions, the photovoltaic conversion efficiency of cells with the novel HPMC-blended gel electrolyte (5.34%) was significantly greater than that of cells without HPMC (3.97%).

Polymer-electrolyte-gated nanowire synaptic transistors for neuromorphic applications

NASA Astrophysics Data System (ADS)

Zou, Can; Sun, Jia; Gou, Guangyang; Kong, Ling-An; Qian, Chuan; Dai, Guozhang; Yang, Junliang; Guo, Guang-hua

2017-09-01

Polymer-electrolytes are formed by dissolving a salt in polymer instead of water, the conducting mechanism involves the segmental motion-assisted diffusion of ion in the polymer matrix. Here, we report on the fabrication of tin oxide (SnO2) nanowire synaptic transistors using polymer-electrolyte gating. A thin layer of poly(ethylene oxide) and lithium perchlorate (PEO/LiClO4) was deposited on top of the devices, which was used to boost device performances. A voltage spike applied on the in-plane gate attracts ions toward the polymer-electrolyte/SnO2 nanowire interface and the ions are gradually returned after the pulse is removed, which can induce a dynamic excitatory postsynaptic current in the nanowire channel. The SnO2 synaptic transistors exhibit the behavior of short-term plasticity like the paired-pulse facilitation and self-adaptation, which is related to the electric double-effect regulation. In addition, the synaptic logic functions and the logical function transformation are also discussed. Such single SnO2 nanowire-based synaptic transistors are of great importance for future neuromorphic devices.

Ultrastable Photoelectrodes for Solar Water Splitting Based on Organic Metal Halide Perovskite Fabricated by Lift-Off Process.

PubMed

Nam, SeongSik; Mai, Cuc Thi Kim; Oh, Ilwhan

2018-05-02

Herein, we report an integrated photoelectrolysis of water employing organic metal halide (OMH) perovskite material. As generic OMH perovskite material and device architecture are highly susceptible to degradation by aqueous electrolytes, we have developed a versatile mold-cast and lift-off process to fabricate and assemble multipurpose metal encapsulation onto perovskite devices. With the metal encapsulation effectively protecting the perovskite cell and also functioning as electrocatalyst, the high-performance perovskite photoelectrodes exhibit high photovoltage and photocurrent that are effectively inherited from the original solid-state solar cell. More importantly, thus-fabricated perovskite photoelectrode demonstrates record-long unprecedented stability even at highly oxidizing potential in strong alkaline electrolyte. We expect that this versatile lift-off process can be adapted in a wide variety of photoelectrochemical devices to protect the material surfaces from corroding electrolyte and facilitate various electrochemical reactions.

Electrolyte gated TFT biosensors based on the Donnan's capacitance of anchored biomolecules

NASA Astrophysics Data System (ADS)

Manoli, Kyriaki; Palazzo, Gerardo; Macchia, Eleonora; Tiwari, Amber; Di Franco, Cinzia; Scamarcio, Gaetano; Favia, Pietro; Mallardi, Antonia; Torsi, Luisa

2017-08-01

Biodetection using electrolyte gated field effect transistors has been mainly correlated to charge modulated transduction. Therefore, such platforms are designed and studied for limited applications involving relatively small charged species and much care is taken in the operating conditions particularly pH and salt concentration (ionic strength). However, there are several reports suggesting that the device conductance can also be very sensitive towards variations in the capacitance coupling. Understanding the sensing mechanism is important for further exploitation of these promising sensors in broader range of applications. In this paper, we present a thorough and in depth study of a multilayer protein system coupled to an electrolyte gated transistor. It is demonstrated that detection associated to a binding event taking place at a distance of 30 nm far from the organic semiconductor-electrolyte interface is possible and the device conductance is dominated by Donnan's capacitance of anchored biomolecules.

Optimization of PEDOT films in ionic liquid supercapacitors: demonstration as a power source for polymer electrochromic devices.

PubMed

Österholm, Anna M; Shen, D Eric; Dyer, Aubrey L; Reynolds, John R

2013-12-26

We report on the optimization of the capacitive behavior of poly(3,4-ethylenedioxythiophene) (PEDOT) films as polymeric electrodes in flexible, Type I electrochemical supercapacitors (ESCs) utilizing ionic liquid (IL) and organic gel electrolytes. The device performance was assessed based on figures of merit that are critical to evaluating the practical utility of electroactive polymer ESCs. PEDOT/IL devices were found to be highly stable over hundreds of thousands of cycles and could be reversibly charged/discharged at scan rates between 500 mV/s and 2 V/s depending on the polymer loading. Furthermore, these devices exhibit leakage currents and self-discharge rates that are comparable to state of the art electrochemical double-layer ESCs. Using an IL as device electrolyte allowed an extension of the voltage window of Type I ESCs by 60%, resulting in a 2.5-fold increase in the energy density obtained. The efficacies of tjese PEDOT ESCs were assessed by using them as a power source for a high-contrast and fast-switching electrochromic device, demonstrating their applicability in small organic electronic-based devices.

Understanding the conductive channel evolution in Na:WO3-x-based planar devices

NASA Astrophysics Data System (ADS)

Shang, Dashan; Li, Peining; Wang, Tao; Carria, Egidio; Sun, Jirong; Shen, Baogen; Taubner, Thomas; Valov, Ilia; Waser, Rainer; Wuttig, Matthias

2015-03-01

An ion migration process in a solid electrolyte is important for ion-based functional devices, such as fuel cells, batteries, electrochromics, gas sensors, and resistive switching systems. In this study, a planar sandwich structure is prepared by depositing tungsten oxide (WO3-x) films on a soda-lime glass substrate, from which Na+ diffuses into the WO3-x films during the deposition. The entire process of Na+ migration driven by an alternating electric field is visualized in the Na-doped WO3-x films in the form of conductive channel by in situ optical imaging combined with infrared spectroscopy and near-field imaging techniques. A reversible change of geometry between a parabolic and a bar channel is observed with the resistance change of the devices. The peculiar channel evolution is interpreted by a thermal-stress-induced mechanical deformation of the films and an asymmetric Na+ mobility between the parabolic and the bar channels. These results exemplify a typical ion migration process driven by an alternating electric field in a solid electrolyte with a low ion mobility and are expected to be beneficial to improve the controllability of the ion migration in ion-based functional devices, such as resistive switching devices.An ion migration process in a solid electrolyte is important for ion-based functional devices, such as fuel cells, batteries, electrochromics, gas sensors, and resistive switching systems. In this study, a planar sandwich structure is prepared by depositing tungsten oxide (WO3-x) films on a soda-lime glass substrate, from which Na+ diffuses into the WO3-x films during the deposition. The entire process of Na+ migration driven by an alternating electric field is visualized in the Na-doped WO3-x films in the form of conductive channel by in situ optical imaging combined with infrared spectroscopy and near-field imaging techniques. A reversible change of geometry between a parabolic and a bar channel is observed with the resistance change of the devices. The peculiar channel evolution is interpreted by a thermal-stress-induced mechanical deformation of the films and an asymmetric Na+ mobility between the parabolic and the bar channels. These results exemplify a typical ion migration process driven by an alternating electric field in a solid electrolyte with a low ion mobility and are expected to be beneficial to improve the controllability of the ion migration in ion-based functional devices, such as resistive switching devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07545e

One step shift towards flexible supercapacitors based on carbon nanotubes - A review

NASA Astrophysics Data System (ADS)

Yar, A.; Dennis, J. O.; Mohamed, N. M.; Mumtaz, A.; Irshad, M. I.; Ahmad, F.

2014-10-01

Supercapacitors have emerged as prominent energy storage devices that offer high energy density compared to conventional capacitors and high power density which is not found in batteries. Carbon nanotubes (CNTs) because of their high surface area and tremendous electrical properties are used as electrode material for supercapacitors. In this review we focused on the factors like surface area, role of the electrolyte and techniques adopted to improve performance of CNTs based supercapacitors. The supercapacitors are widely tested in liquid electrolytes which are normally hazardous in nature, toxic, flammable and their leakage has safety concerns. This review also focuses on research which is replacing these unsafe electrolytes by solid electrolytes with the combination of low cost CNTs deposited flexible supports for supercapacitors.

Impedance studies of a green blend polymer electrolyte based on PVA and Aloe-vera

NASA Astrophysics Data System (ADS)

Selvalakshmi, S.; Mathavan, T.; Vijaya, N.; Selvasekarapandian, Premalatha, M.; Monisha, S.

2016-05-01

The development of polymer electrolyte materials for energy generating and energy storage devices is a challenge today. A new type of blended green electrolyte based on Poly-vinyl alcohol (PVA) and Aloe-vera has been prepared by solution casting technique. The blending of polymers may lead to the increase in stability due to one polymer portraying itself as a mechanical stiffener and the other as a gelled matrix supported by the other. The prepared blend electrolytes were subjected to Ac impedance studies. It has been found out that the polymer film in which 1 gm of PVA was dissolved in 40 ml of Aloe-vera extract exhibits highest conductivity and its value is 3.08 × 10-4 S cm-1.

Integrated seal for high-temperature electrochemical device

DOEpatents

Tucker, Michael C; Jacobson, Craig P

2013-07-16

The present invention provides electrochemical device structures having integrated seals, and methods of fabricating them. According to various embodiments the structures include a thin, supported electrolyte film with the electrolyte sealed to the support. The perimeter of the support is self-sealed during fabrication. The perimeter can then be independently sealed to a manifold or other device, e.g., via an external seal. According to various embodiments, the external seal does not contact the electrolyte, thereby eliminating the restrictions on the sealing method and materials imposed by sealing against the electrolyte.

Supercapacitors based on modified graphene electrodes with poly(ionic liquid)

NASA Astrophysics Data System (ADS)

Trigueiro, João Paulo C.; Lavall, Rodrigo L.; Silva, Glaura G.

2014-06-01

The improved accessibility of the electrolyte to the surface of carbon nanomaterials is a challenge to be overcome in supercapacitors based on ionic liquid electrolytes. In this study, we report the preparation of supercapacitors based on reduced graphene oxide (RGO) electrodes and ionic liquid as the electrolyte (specifically, 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide or [MPPy][TFSI]). Two types of electrodes were compared: the RGO-based electrode and a poly(ionic liquid)-modified RGO electrode (PIL:RGO). The supercapacitor produced with the PIL:RGO electrode and [MPPy][TFSI] showed an electrochemical stability of 3 V and provided a capacitance of 71.5 F g-1 at room temperature; this capacitance is 130% higher with respect to the RGO-based supercapacitor. The decrease of the specific capacitance after 2000 cycles is only 10% for the PIL:RGO-based device. The results revealed the potential of the PIL:RGO material as an electrode for supercapacitors. This composite electrode increases the compatibility with the ionic liquid electrolyte compared to an RGO electrode, promoting an increase in the effective surface area of the electrode accessible to the electrolyte ions.

The thermal stability of sodium beta'-Alumina solid electrolyte ceramic in AMTEC cells

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

Williams, Roger M.; Ryan, Margaret A.; Homer, Margie L.

1999-01-22

A critical component of alkali metal thermal-to electric converter (AMTEC) devices for long duration space missions is the beta'-alumina solid electrolyte ceramic (BASE), for which there exists no substitute. The temperature and environmental conditions under which BASE remains stable control operational parameters of AMTEC devices. We have used mass loss experiments in vacuum to 1573K to characterize the kinetics of BASE decomposition, and conductivity and exchange current measurements in sodium vapor filled exposure cells to 1223K to investigate changes in the BASE which affect its ionic conductivity. There is no clear evidence of direct thermal decomposition of BASE below 1273K,more » although limited soda loss may occur. Reactive metals such as Mn or Cr can react with BASE at temperatures at least as low as 1223K.« less

Development of Bipolar All-solid-state Lithium Battery Based on Quasi-solid-state Electrolyte Containing Tetraglyme-LiTFSA Equimolar Complex

PubMed Central

Gambe, Yoshiyuki; Sun, Yan; Honma, Itaru

2015-01-01

The development of high energy–density lithium-ion secondary batteries as storage batteries in vehicles is attracting increasing attention. In this study, high-voltage bipolar stacked batteries with a quasi-solid-state electrolyte containing a Li-Glyme complex were prepared, and the performance of the device was evaluated. Via the successful production of double-layered and triple-layered high-voltage devices, it was confirmed that these stacked batteries operated properly without any internal short-circuits of a single cell within the package: Their plateau potentials (6.7 and 10.0 V, respectively) were two and three times that (3.4 V) of the single-layered device, respectively. Further, the double-layered device showed a capacity retention of 99% on the 200th cycle at 0.5 C, which is an indication of good cycling properties. These results suggest that bipolar stacked batteries with a quasi-solid-state electrolyte containing a Li-Glyme complex could readily produce a high voltage of 10 V. PMID:25746860

Nano-Nucleation Characteristic of Cu-Ag Alloy Directly Electrodeposited on W Diffusion Barrier for Microelectronic Device Interconnect.

PubMed

Kim, Kang O; Kim, Sunjung

2016-05-01

Cu-Ag alloy interconnect is promising for ultra-large-scale integration (ULSI) microelectronic system of which device dimension keeps shrinking. In this study, seedless electrodeposition of Cu-Ag alloy directly on W diffusion barrier as interconnect technology is presented in respect of nano-nucleation control. Chemical equilibrium state of electrolyte was fundamentally investigated according to the pH of electrolyte because direct nano-nucleation of Cu-Ag alloy on W surface is challenging. Chelation behavior of Cu2+ and Ag+ ions with citrate (Cit) and ammonia ligands was dependent on the pH of electrolyte. The amount and kind of Cu- and Ag-based complexes determine the deposition rate, size, elemental composition, and surface morphology of Cu-Ag alloy nano-nuclei formed on W surface.

An aqueous electrolyte, sodium ion functional, large format energy storage device for stationary applications

NASA Astrophysics Data System (ADS)

Whitacre, J. F.; Wiley, T.; Shanbhag, S.; Wenzhuo, Y.; Mohamed, A.; Chun, S. E.; Weber, E.; Blackwood, D.; Lynch-Bell, E.; Gulakowski, J.; Smith, C.; Humphreys, D.

2012-09-01

An approach to making large format economical energy storage devices based on a sodium-interactive set of electrodes in a neutral pH aqueous electrolyte is described. The economics of materials and manufacturing are examined, followed by a description of an asymmetric/hybrid device that has λ-MnO2 positive electrode material and low cost activated carbon as the negative electrode material. Data presented include materials characterization of the active materials, cyclic voltammetry, galvanostatic charge/discharge cycling, and application-specific performance of an 80 V, 2.4 kW h pack. The results indicate that this set of electrochemical couples is stable, low cost, requires minimal battery management control electronics, and therefore has potential for use in stationary applications where device energy density is not a concern.

Higher Efficiency for Quasi-Solid State Dye Sensitized Solar Cells Under Low Light Irradiance

NASA Astrophysics Data System (ADS)

Desilva, Ajith; Bandara, T. M. W. J.; Fernado, H. D. N. S.; Fernando, P. S. L.; Dissanayake, M. A. K. L.; Jayasundara, W. J. M. J. S. R.; Furlani, M.; Mellander, B.-E.

2014-03-01

Dye-sensitized solar cells (DSSCs), lower cost solar energy conversion devices are alternative green energy source. The liquid based electrolyte DSSCs have higher efficiencies with many practical issues while the quasi-solid-state DSSCs resolve the key problems but efficiencies are relatively low. Polyacrylonitrile (PAN) based gel polymer electrolytes were fabricated as DSSCs by incorporating ethylene carbonate and propylene carbonate plasticizers and tetrapropylammonium iodide salt. A thin layer of electrolyte was sandwiched between the TiO2 anode (sensitized with N719 dye) and the Pt counter electrode. The electrolyte had an ionic conductivity of 2.6 mS/cm at 25 degrees of Celsius. DSSCs incorporating this gel electrolyte revealed Vsc circuit, Jsc, fill factor (FF) and efficiency values of 0.71 V, 11.8 mA, 51 percent and 4.2 percent respectively under 1 sun irradiation. The efficiency of the cell increased with decreasing solar irradiance achieving up to 10 percent efficiency and 80 percent FF at low irradiance values. This work uncovers that quasi-solid state DSSCs can reach efficiencies close to that of liquid electrolytes based cells.

Nanostructured transparent conducting oxide electrochromic device

DOEpatents

Milliron, Delia; Tangirala, Ravisubhash; Llordes, Anna; Buonsanti, Raffaella; Garcia, Guillermo

2016-05-17

The embodiments described herein provide an electrochromic device. In an exemplary embodiment, the electrochromic device includes (1) a substrate and (2) a film supported by the substrate, where the film includes transparent conducting oxide (TCO) nanostructures. In a further embodiment, the electrochromic device further includes (a) an electrolyte, where the nanostructures are embedded in the electrolyte, resulting in an electrolyte, nanostructure mixture positioned above the substrate and (b) a counter electrode positioned above the mixture. In a further embodiment, the electrochromic device further includes a conductive coating deposited on the substrate between the substrate and the mixture. In a further embodiment, the electrochromic device further includes a second substrate positioned above the mixture.

Electrolytic cell with reference electrode

DOEpatents

Kessie, Robert W.

1989-01-01

A reference electrode device is provided for a high temperature electrolytic cell used to electrolytically recover uranium from spent reactor fuel dissolved in an anode pool, the device having a glass tube to enclose the electrode and electrolyte and serve as a conductive membrane with the cell electrolyte, and an outer metal tube about the glass tube to serve as a shield and basket for any glass sections broken by handling of the tube to prevent their contact with the anode pool, the metal tube having perforations to provide access between the bulk of the cell electrolyte and glass membrane.

Reference electrode for electrolytic cell

DOEpatents

Kessie, R.W.

1988-07-28

A reference electrode device is provided for a high temperature electrolytic cell used to electrolytically recover uranium from spent reactor fuel dissolved in an anode pool, the device having a glass tube to enclose the electrode and electrolyte and serve as a conductive membrane with the cell electrolyte, and an outer metal tube about the glass tube to serve as a shield and basket for any glass sections broken by handling of the tube to prevent their contact with the anode pool, the metal tube having perforations to provide access between the bulk of the cell electrolyte and glass membrane. 4 figs.

Hybrid radical energy storage device and method of making

DOEpatents

Gennett, Thomas; Ginley, David S.; Braunecker, Wade; Ban, Chunmei; Owczarczyk, Zbyslaw

2016-04-26

Hybrid radical energy storage devices, such as batteries or electrochemical devices, and methods of use and making are disclosed. Also described herein are electrodes and electrolytes useful in energy storage devices, for example, radical polymer cathode materials and electrolytes for use in organic radical batteries.

Hybrid radical energy storage device and method of making

DOEpatents

Gennett, Thomas; Ginley, David S; Braunecker, Wade; Ban, Chunmei; Owczarczyk, Zbyslaw

2015-01-27

Hybrid radical energy storage devices, such as batteries or electrochemical devices, and methods of use and making are disclosed. Also described herein are electrodes and electrolytes useful in energy storage devices, for example, radical polymer cathode materials and electrolytes for use in organic radical batteries.

Enhanced photoelectric performance in self-powered UV detectors based on ZnO nanowires with plasmonic Au nanoparticles scattered electrolyte

NASA Astrophysics Data System (ADS)

Zeng, Yiyu; Ye, Zhizhen; Lu, Bin; Dai, Wei; Pan, Xinhua

2016-04-01

Vertically aligned ZnO nanowires (NWs) were grown on a fluorine-doped tin-oxide-coated glass substrate by a hydrothermal method. Au nanoparticles were well dispersed in the mixed solution of ethanol and deionized water. A simple self-powered ultraviolet detector based on solid-liquid heterojunction was fabricated, utilizing ZnO NWs as active photoanode and such prepared mixed solution as electrolyte. The introduction of Au nanoparticles results in considerable improvements in the responsivity and sensitivity of the device compared with the one using deionized water as electrolyte, which is attributed to the enhanced light harvesting by Au nanoparticles.

Insights into the use of polyethylene oxide in energy storage/conversion devices: a critical review

NASA Astrophysics Data System (ADS)

Arya, Anil; Sharma, A. L.

2017-11-01

In this review, the latest updates in poly (ethylene oxide) based electrolytes are summarized. The ultimate goal of researchers globally is towards the development of free-standing solid polymeric separators for energy storage devices. This single free-standing solid polymeric separator may replace the liquid and separator (organic/inorganic) used in existing efficient/smart energy technology. As an example, polyethylene oxide (PEO) consists of an electron donor-rich group which provides coordinating sites to the cation for migration. Owing to this exclusive structure, PEO exhibits some remarkable properties, such as a low glass transition temperature, excellent flexibility, and the ability to make complexation with various metal salts which are unattainable by another polymer host. Hence, the PEO is an emerging candidate that has been most examined or is currently under consideration for application in energy storage devices. This review article first provides a detailed study of the PEO properties, characteristics of the constituents of the polymer electrolyte, and suitable approaches for the modification of polymer electrolytes. Then, the synthesization and characterizations techniques are outlined. The structures, characteristics, and performance during charge-discharge of four types of electrolyte/separators (liquid, plasticized, and dispersed and intercalated electrolyte) are highlighted. The suitable ion transport mechanism proposed by researchers in different renowned groups have been discussed for the better understanding of the ion dynamics in such systems.

Sub-0.5 V Highly Stable Aqueous Salt Gated Metal Oxide Electronics

PubMed Central

Park, Sungjun; Lee, SeYeong; Kim, Chang-Hyun; Lee, Ilseop; Lee, Won-June; Kim, Sohee; Lee, Byung-Geun; Jang, Jae-Hyung; Yoon, Myung-Han

2015-01-01

Recently, growing interest in implantable bionics and biochemical sensors spurred the research for developing non-conventional electronics with excellent device characteristics at low operation voltages and prolonged device stability under physiological conditions. Herein, we report high-performance aqueous electrolyte-gated thin-film transistors using a sol-gel amorphous metal oxide semiconductor and aqueous electrolyte dielectrics based on small ionic salts. The proper selection of channel material (i.e., indium-gallium-zinc-oxide) and precautious passivation of non-channel areas enabled the development of simple but highly stable metal oxide transistors manifested by low operation voltages within 0.5 V, high transconductance of ~1.0 mS, large current on-off ratios over 107, and fast inverter responses up to several hundred hertz without device degradation even in physiologically-relevant ionic solutions. In conjunction with excellent transistor characteristics, investigation of the electrochemical nature of the metal oxide-electrolyte interface may contribute to the development of a viable bio-electronic platform directly interfacing with biological entities in vivo. PMID:26271456

The influence of electrode and separator thickness on the cell resistance of symmetric cellulose-polypyrrole-based electric energy storage devices

NASA Astrophysics Data System (ADS)

Tammela, Petter; Olsson, Henrik; Strømme, Maria; Nyholm, Leif

2014-12-01

The influence of the cell design of symmetric polypyrrole and cellulose-based electric energy storage devices on the cell resistance was investigated using chronopotentiometric and ac impedance measurements with different separator and electrode thicknesses. The cell resistance was found to be dominated by the electrolyte and current collector resistances while the contribution from the composite electrode material was negligible. Due to the electrolyte within the porous electrodes thin separators could be used in combination with thick composite electrodes without loss of performance. The paper separator contributed with a resistance of ∼1.5 Ω mm-1 in a 1.0 M NaNO3 electrolyte and the tortuosity value for the separator was about 2.5. The contribution from the graphite foil current collectors was about ∼0.4-1.1 Ω and this contribution could not be reduced by using platinum foil current collectors due to larger contact resistances. The introduction of chopped carbon fibres into the electrode material or the application of pressure across the cells, however, decreased the charge transfer resistance significantly. As the present results demonstrate that cells with higher charge storage capacities but with the same cell resistance can be obtained by increasing the electrode thickness, the development of paper based energy storage devices is facilitated.

Intrinsically stretchable supercapacitors composed of polypyrrole electrodes and highly stretchable gel electrolyte.

PubMed

Zhao, Chen; Wang, Caiyun; Yue, Zhilian; Shu, Kewei; Wallace, Gordon G

2013-09-25

There has been an emerging interest in stretchable power sources compatible with flexible/wearable electronics. Such power sources must be able to withstand large mechanical strains and still maintain function. Here we report a highly stretchable H3PO4-poly(vinyl alcohol) (PVA) polymer electrolyte obtained by optimizing the polymer molecular weight and its weight ratio to H3PO4 in terms of conductivity and mechanical properties. The electrolyte demonstrates a high conductivity of 3.4 × 10(-3) S cm(-1), and a high fracture strain at 410% elongation. It is mechanically robust with a tensile strength of 2 MPa and a Young's modulus of 1 MPa, and displays a small plastic deformation (5%) after 1000 stretching cycles at 100% strain. A stretchable supercapacitor device has been developed based on buckled polypyrrole electrodes and the polymer electrolyte. The device shows only a small capacitance loss of 5.6% at 30% strain, and can retain 81% of the initial capacitance after 1000 cycles of such stretching.

Influence of temperature and electrolyte on the performance of activated-carbon supercapacitors

NASA Astrophysics Data System (ADS)

Liu, Ping; Verbrugge, Mark; Soukiazian, Souren

For hybrid electric vehicle traction applications, energy storage devices with high power density and energy efficiency are required. A primary attribute of supercapacitors is that they retain their high power density and energy efficiency even at -30 °C, the lowest temperature at which unassisted starting must be provided to customers. More abuse-tolerant electrolytes are preferred to the high-conductivity acetonitrile-based systems commonly employed. Propylene carbonate based electrolytes are a promising alternative. In this work, we compare the electrochemical performance of two high-power density electrical double layer supercapacitors employing acetonitrile and propylene carbonate as solvents. From this study, we are able to elucidate phenomena that control the resistance of supercapacitor at lower temperatures, and quantify the difference in performance associated with the two electrolytes.

One step shift towards flexible supercapacitors based on carbon nanotubes - A review

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

Yar, A., E-mail: asfandyarhargan@gmail.com, E-mail: johndennis@petronas.com.my, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: asad-032@yahoo.com, E-mail: imrancssp@gmail.com; Dennis, J. O., E-mail: asfandyarhargan@gmail.com, E-mail: johndennis@petronas.com.my, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: asad-032@yahoo.com, E-mail: imrancssp@gmail.com; Mohamed, N. M., E-mail: asfandyarhargan@gmail.com, E-mail: johndennis@petronas.com.my, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: asad-032@yahoo.com, E-mail: imrancssp@gmail.com

2014-10-24

Supercapacitors have emerged as prominent energy storage devices that offer high energy density compared to conventional capacitors and high power density which is not found in batteries. Carbon nanotubes (CNTs) because of their high surface area and tremendous electrical properties are used as electrode material for supercapacitors. In this review we focused on the factors like surface area, role of the electrolyte and techniques adopted to improve performance of CNTs based supercapacitors. The supercapacitors are widely tested in liquid electrolytes which are normally hazardous in nature, toxic, flammable and their leakage has safety concerns. This review also focuses on researchmore » which is replacing these unsafe electrolytes by solid electrolytes with the combination of low cost CNTs deposited flexible supports for supercapacitors.« less

α,ω-dihexyl-sexithiophene thin films for solution-gated organic field-effect transistors

NASA Astrophysics Data System (ADS)

Schamoni, Hannah; Noever, Simon; Nickel, Bert; Stutzmann, Martin; Garrido, Jose A.

2016-02-01

While organic semiconductors are being widely investigated for chemical and biochemical sensing applications, major drawbacks such as the poor device stability and low charge carrier mobility in aqueous electrolytes have not yet been solved to complete satisfaction. In this work, solution-gated organic field-effect transistors (SGOFETs) based on the molecule α,ω-dihexyl-sexithiophene (DH6T) are presented as promising platforms for in-electrolyte sensing. Thin films of DH6T were investigated with regard to the influence of the substrate temperature during deposition on the grain size and structural order. The performance of SGOFETs can be improved by choosing suitable growth parameters that lead to a two-dimensional film morphology and a high degree of structural order. Furthermore, the capability of the SGOFETs to detect changes in the pH or ionic strength of the gate electrolyte is demonstrated and simulated. Finally, excellent transistor stability is confirmed by continuously operating the device over a period of several days, which is a consequence of the low threshold voltage of DH6T-based SGOFETs. Altogether, our results demonstrate the feasibility of high performance and highly stable organic semiconductor devices for chemical or biochemical applications.

Structures and fabrication techniques for solid state electrochemical devices

DOEpatents

Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

2006-10-10

Low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures provide solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one aspect the invention provides techniques for co-firing of device substrate (often an electrode) with an electrolyte or membrane layer to form densified electrolyte/membrane films 5 to 20 microns thick. In another aspect, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe and Cu, or alloys thereof.

A compact model for selectors based on metal doped electrolyte

NASA Astrophysics Data System (ADS)

Zhang, Lu; Song, Wenhao; Yang, J. Joshua; Li, Hai; Chen, Yiran

2018-04-01

A selector device that demonstrates high nonlinearity and low switching voltages was fabricated using HfOx as a solid electrolyte doped with Ag electrodes. The electronic conductance of the volatile conductive filaments responsible for the switching was studied under both static and dynamic conditions. A compact model is developed from this study that describes the physical processes of the formation and rupture of the Ag filament(s). A dynamic capacitance model is used to fit the transient current traces under different voltage bias, which enables the extraction of parameters associated with the various parasitic components in the device.

Carbon-Based Materials for Lithium-Ion Batteries, Electrochemical Capacitors, and Their Hybrid Devices.

PubMed

Yao, Fei; Pham, Duy Tho; Lee, Young Hee

2015-07-20

A rapidly developing market for portable electronic devices and hybrid electrical vehicles requires an urgent supply of mature energy-storage systems. As a result, lithium-ion batteries and electrochemical capacitors have lately attracted broad attention. Nevertheless, it is well known that both devices have their own drawbacks. With the fast development of nanoscience and nanotechnology, various structures and materials have been proposed to overcome the deficiencies of both devices to improve their electrochemical performance further. In this Review, electrochemical storage mechanisms based on carbon materials for both lithium-ion batteries and electrochemical capacitors are introduced. Non-faradic processes (electric double-layer capacitance) and faradic reactions (pseudocapacitance and intercalation) are generally explained. Electrochemical performance based on different types of electrolytes is briefly reviewed. Furthermore, impedance behavior based on Nyquist plots is discussed. We demonstrate the influence of cell conductivity, electrode/electrolyte interface, and ion diffusion on impedance performance. We illustrate that relaxation time, which is closely related to ion diffusion, can be extracted from Nyquist plots and compared between lithium-ion batteries and electrochemical capacitors. Finally, recent progress in the design of anodes for lithium-ion batteries, electrochemical capacitors, and their hybrid devices based on carbonaceous materials are reviewed. Challenges and future perspectives are further discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wide electrochemical window solvents for use in electrochemical devices and electrolyte solutions incorporating such solvents

DOEpatents

Angell, Charles Austen; Zhang, Sheng-Shui; Xu, Kang

1998-01-01

The present invention relates to electrolyte solvents for use in liquid or rubbery electrolyte solutions. Specifically, this invention is directed to boron-containing electrolyte solvents and boron-containing electrolyte solutions.

Organic-inorganic hybrid polymer electrolytes based on polyether diamine, alkoxysilane, and trichlorotriazine: Synthesis, characterization, and electrochemical applications

NASA Astrophysics Data System (ADS)

Saikia, Diganta; Wu, Cheng-Gang; Fang, Jason; Tsai, Li-Duan; Kao, Hsien-Ming

2014-12-01

A new type of highly conductive organic-inorganic hybrid polymer electrolytes has been synthesized by the reaction of poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether), 2,4,6-trichloro-1,3,5-triazine and alkoxysilane precursor 3-(glycidyloxypropyl)trimethoxysilane, followed by doping of LiClO4. The 13C and 29Si solid-sate NMR results confirm the successful synthesis of the organic-inorganic hybrid structure. The solid hybrid electrolyte thus obtained exhibits a maximum ionic conductivity of 1.6 × 10-4 S cm-1 at 30 °C, which is the highest among the organic-inorganic hybrid electrolytes. The hybrid electrolytes are electrochemically stable up to 4.2 V. The prototype electrochromic device with such a solid hybrid electrolyte demonstrates a good coloration efficiency value of 183 cm2 C-1 with a cycle life over 200 cycles. For the lithium-ion battery test, the salt free solid hybrid membrane is swelled with a LiPF6-containing electrolyte solution to reach an acceptable ionic conductivity value of 6.5 × 10-3 S cm-1 at 30 °C. The battery cell carries an initial discharge capacity of 100 mAh g-1 at 0.2C-rate and a coulombic efficiency of about 95% up to 30 cycles without the sign of cell failure. The present organic-inorganic hybrid electrolytes hold promise for applications in electrochromic devices and lithium ion batteries.

Conductivity studies of PEG based polymer electrolyte for applications as electrolyte in ion batteries

NASA Astrophysics Data System (ADS)

Patil, Ravikumar V.; Praveen, D.; Damle, R.

2018-05-01

Development of lithium ion batteries employing solid polymer electrolytes as electrolyte material has led to efficient energy storage and usage in many portable devices. However, due to a few drawbacks like lower ionic conductivity of solid polymer electrolytes (SPEs), studies on SPEs for improvement in conductivity still have a good scope. In the present paper, we report the conductivity studies of a new SPE with low molecular weight poly ethylene glycol (PEG) as host polymer in which a salt with larger anion Lithium trifluro methane sulphonate (LTMS). XRD studies have revealed that the salt completely dissociates in the polymer giving a good stable electrolyte at lower salt concentration. Conductivity of the SPEs has been studied as a function of temperature and we reiterate that the conductivity is a thermally activated process and follows Arrhenius type behavior.

Transparent bifacial dye-sensitized solar cells based on organic counter electrodes and iodine-free electrolyte

NASA Astrophysics Data System (ADS)

Ku, Zhiliang; Rong, Yaoguang; Han, Hongwei

2013-10-01

In this study, a novel bifacially active transparent dye-sensitized solar cell (DSSCs) assembled with a transparent poly(3,4-ethylenedioxythiophene) (PEDOT) counter electrode and a colorless iodine-free polymer gel (IFPG) electrolyte was developed. The IFPG electrolyte was prepared by employing an ionic liquid (1,2-dimethyl-3-propylinmidazolium iodide, DMPII) as the charge transfer intermediate and a polymer composite as the gelator without the addition of iodine, exhibiting high conductivity and non-absorption characters. PEDOT electrodes were prepared via a facile electro-polymerization method. By controlling the amount of polymerization charge capacity, we optimized the PEDOT electrodes with high transparency and a favorable activity for catalyzing the IFPG electrolyte. The bifacial DSSCs device fabricated by this kind of transparent PEDOT electrode and colorless IFPG electrolyte showed a power conversion efficiency (PCE) of 6.35% and 4.98% at 100 mW cm-2 AM1.5 illumination corresponding to front- and rear-side illumination. It is notable that the PCE under rear-side illumination approaches 80% that of front-side illumination. Moreover, the device shows excellent stability as confirmed by aging test. These promising results highlight the enormous potential of this transparent PEDOT CE and colorless IFPG electrolyte in scaling up and commercialization of low cost and effective bifacial DSSCs.

Solid electrolyte-electrode system for an electrochemical cell

DOEpatents

Tuller, Harry L.; Kramer, Steve A.; Spears, Marlene A.

1995-01-01

An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is also provided.

Performance of Liquid Phase Exfoliated Graphene As Electrochemical Double Layer Capacitors Electrodes

NASA Astrophysics Data System (ADS)

Huffstutler, Jacob; Wasala, Milinda; Richie, Julianna; Winchester, Andrew; Ghosh, Sujoy; Kar, Swastik; Talapatra, Saikat

2014-03-01

We will present the results of our investigations of electrochemical double layer capacitors (EDLCs) or supercapacitors (SC) fabricated using liquid-phase exfoliated graphene. Several electrolytes, such as aqueous potassium hydroxide KOH (6M), ionic 1-Butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], and ionic 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate[BMP][FAP] were used. These EDLC's show good performance compared to other carbon nanomaterials based EDLC's devices. We found that the liquid phase exfoliated graphene based devices possess specific capacitance values as high as 262 F/g, when used with ionic liquid electrolyte[BMP][FAP], with power densities (~ 454 W/kg) and energy densities (~ 0.38Wh/kg). Further, these devices indicated rapid charge transfer response even without the use of any binders or specially prepared current collectors. A detailed electrochemical impedance spectroscopy analysis in order to understand the phenomenon of charge storage in these materials will be presented.

Understanding the conductive channel evolution in Na:WO(3-x)-based planar devices.

PubMed

Shang, Dashan; Li, Peining; Wang, Tao; Carria, Egidio; Sun, Jirong; Shen, Baogen; Taubner, Thomas; Valov, Ilia; Waser, Rainer; Wuttig, Matthias

2015-04-14

An ion migration process in a solid electrolyte is important for ion-based functional devices, such as fuel cells, batteries, electrochromics, gas sensors, and resistive switching systems. In this study, a planar sandwich structure is prepared by depositing tungsten oxide (WO(3-x)) films on a soda-lime glass substrate, from which Na(+) diffuses into the WO(3-x) films during the deposition. The entire process of Na(+) migration driven by an alternating electric field is visualized in the Na-doped WO(3-x) films in the form of conductive channel by in situ optical imaging combined with infrared spectroscopy and near-field imaging techniques. A reversible change of geometry between a parabolic and a bar channel is observed with the resistance change of the devices. The peculiar channel evolution is interpreted by a thermal-stress-induced mechanical deformation of the films and an asymmetric Na(+) mobility between the parabolic and the bar channels. These results exemplify a typical ion migration process driven by an alternating electric field in a solid electrolyte with a low ion mobility and are expected to be beneficial to improve the controllability of the ion migration in ion-based functional devices, such as resistive switching devices.

GaN light-emitting device based on ionic liquid electrolyte

NASA Astrophysics Data System (ADS)

Hirai, Tomoaki; Sakanoue, Tomo; Takenobu, Taishi

2018-06-01

Ionic liquids (ILs) are attractive materials for fabricating unique hybrid devices based on electronics and electrochemistry; thus, IL-gated transistors and organic light-emitting devices of light-emitting electrochemical cells (LECs) are investigated for future low-voltage and high-performance devices. In LECs, voltage application induces the formation of electrochemically doped p–n homojunctions owing to ion rearrangements in composites of semiconductors and electrolytes, and achieves electron–hole recombination for light emission at the homojunctions. In this work, we applied this concept of IL-induced electrochemical doping to the fabrication of GaN-based light-emitting devices. We found that voltage application to the layered IL/GaN structure accumulated electrons on the GaN surface owing to ion rearrangements and improved the conductivity of GaN. The ion rearrangement also enabled holes to be injected by the strong electric field of electric double layers on hole injection contacts. This simultaneous injection of holes and electrons into GaN mediated by ions achieves light emission at a low voltage of around 3.4 V. The light emission from the simple IL/GaN structure indicates the usefulness of an electrochemical technique in generating light emission with great ease of fabrication.

Highly conducting leakage-free electrolyte for SrCoOx-based non-volatile memory device

NASA Astrophysics Data System (ADS)

Katase, Takayoshi; Suzuki, Yuki; Ohta, Hiromichi

2017-10-01

The electrochemical switching of SrCoOx-based non-volatile memory with a thin-film-transistor structure was examined by using liquid-leakage-free electrolytes with different conductivities (σ) as the gate insulator. We first examined leakage-free water, which is incorporated in the amorphous (a-) 12CaO.7Al2O3 film with a nanoporous structure (Calcium Aluminate with Nanopore), but the electrochemical oxidation/reduction of the SrCoOx layer required the application of a high gate voltage (Vg) up to 20 V for a very long current-flowing-time (t) ˜40 min, primarily due to the low σ [2.0 × 10-8 S cm-1 at room temperature (RT)] of leakage-free water. We then controlled the σ of the leakage-free electrolyte, infiltrated in the a-NaxTaO3 film with a nanopillar array structure, from 8.0 × 10-8 S cm-1 to 2.5 × 10-6 S cm-1 at RT by changing the x = 0.01-1.0. As the result, the t, required for the metallization of the SrCoOx layer under small Vg = -3 V, becomes two orders of magnitude shorter with increase of the σ of the a-NaxTaO3 leakage-free electrolyte. These results indicate that the ion migration in the leakage-free electrolyte is the rate-determining step for the electrochemical switching, compared to the other electrochemical process, and the high σ of the leakage-free electrolyte is the key factor for the development of the non-volatile SrCoOx-based electro-magnetic phase switching device.

Oxide-based synaptic transistors gated by solution-processed gelatin electrolytes

NASA Astrophysics Data System (ADS)

He, Yinke; Sun, Jia; Qian, Chuan; Kong, Ling-An; Gou, Guangyang; Li, Hongjian

2017-04-01

In human brain, a large number of neurons are connected via synapses. Simulation of the synaptic behaviors using electronic devices is the most important step for neuromorphic systems. In this paper, proton conducting gelatin electrolyte-gated oxide field-effect transistors (FETs) were used for emulating synaptic functions, in which the gate electrode is regarded as pre-synaptic neuron and the channel layer as the post-synaptic neuron. In analogy to the biological synapse, a potential spike can be applied at the gate electrode and trigger ionic motion in the gelatin electrolyte, which in turn generates excitatory post-synaptic current (EPSC) in the channel layer. Basic synaptic behaviors including spike time-dependent EPSC, paired-pulse facilitation (PPF), self-adaptation, and frequency-dependent synaptic transmission were successfully mimicked. Such ionic/electronic hybrid devices are beneficial for synaptic electronics and brain-inspired neuromorphic systems.

Structures And Fabrication Techniques For Solid State Electrochemical Devices

DOEpatents

Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

2005-12-27

Provided are low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures. The invention provides solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one embodiment the invention provides techniques for co-firing of device substrate (often an electrode) with an electrolyte or membrane layer to form densified electrolyte/membrane films 5 to 20 microns thick. In another embodiment, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe, Cu and Ag, or alloys thereof.

Structures and fabrication techniques for solid state electrochemical devices

DOEpatents

Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

2003-08-12

Provided are low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures. The invention provides solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one embodiment the invention provides techniques for co-firing of device substrate (often an electrode) with an electrolyte or membrane layer to form densified electrolyte/membrane films 5 to 20 microns thick. In another embodiment, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe, Cu and Ag, or alloys thereof.

A high performance flexible all solid state supercapacitor based on the MnO2 sphere coated macro/mesoporous Ni/C electrode and ionic conducting electrolyte

NASA Astrophysics Data System (ADS)

Zhi, Jian; Reiser, Oliver; Wang, Youfu; Hu, Aiguo

2016-06-01

A high contact resistance between the active materials and the current collector, a low ionic conductivity of the gel electrolyte, and an impenetrable electrode structure are the three major barriers which greatly limit the capacitance of MnO2 in solid state supercapacitors. As a potential solution to these problems, in this work we report a novel electrode for solid state supercapacitors, based on a ternary system composed of hierarchical MnO2 spheres as the active material, macroporous Ni foam as gel penetrable skeletons and an ordered mesoporous carbon (OMC) membrane as the charge-transport accelerating layer. By employing butyl-3-methylimidazolium chloride (BMIMCl) modified gels as the ionic conducting electrolyte, the utilization efficiency of MnO2 on the specific capacitance was enhanced up to 88% of the theoretical value, delivering a volumetric capacitance of 81 F cm-3, which is the highest value among MnO2 based solid state supercapacitors. Moreover, such a flexible device exhibits exceptional volumetric energy and power density (6.6 Wh L-1 and 549 W L-1, based on the whole device volume) combined with a small capacity loss of 8.5% after 6000 cycles under twisting. These encouraging findings unambiguously overcome the energy bottleneck of MnO2 in solid state supercapacitors, and open up a new application of macro/mesoporous materials in flexible devices.A high contact resistance between the active materials and the current collector, a low ionic conductivity of the gel electrolyte, and an impenetrable electrode structure are the three major barriers which greatly limit the capacitance of MnO2 in solid state supercapacitors. As a potential solution to these problems, in this work we report a novel electrode for solid state supercapacitors, based on a ternary system composed of hierarchical MnO2 spheres as the active material, macroporous Ni foam as gel penetrable skeletons and an ordered mesoporous carbon (OMC) membrane as the charge-transport accelerating layer. By employing butyl-3-methylimidazolium chloride (BMIMCl) modified gels as the ionic conducting electrolyte, the utilization efficiency of MnO2 on the specific capacitance was enhanced up to 88% of the theoretical value, delivering a volumetric capacitance of 81 F cm-3, which is the highest value among MnO2 based solid state supercapacitors. Moreover, such a flexible device exhibits exceptional volumetric energy and power density (6.6 Wh L-1 and 549 W L-1, based on the whole device volume) combined with a small capacity loss of 8.5% after 6000 cycles under twisting. These encouraging findings unambiguously overcome the energy bottleneck of MnO2 in solid state supercapacitors, and open up a new application of macro/mesoporous materials in flexible devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02215d

Solid electrolyte-electrode system for an electrochemical cell

DOEpatents

Tuller, H.L.; Kramer, S.A.; Spears, M.A.

1995-04-04

An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is also provided. 17 figures.

Significant Performance Enhancement in Asymmetric Supercapacitors based on Metal Oxides, Carbon nanotubes and Neutral Aqueous Electrolyte.

PubMed

Singh, Arvinder; Chandra, Amreesh

2015-10-23

Amongst the materials being investigated for supercapacitor electrodes, carbon based materials are most investigated. However, pure carbon materials suffer from inherent physical processes which limit the maximum specific energy and power that can be achieved in an energy storage device. Therefore, use of carbon-based composites with suitable nano-materials is attaining prominence. The synergistic effect between the pseudocapacitive nanomaterials (high specific energy) and carbon (high specific power) is expected to deliver the desired improvements. We report the fabrication of high capacitance asymmetric supercapacitor based on electrodes of composites of SnO2 and V2O5 with multiwall carbon nanotubes and neutral 0.5 M Li2SO4 aqueous electrolyte. The advantages of the fabricated asymmetric supercapacitors are compared with the results published in the literature. The widened operating voltage window is due to the higher over-potential of electrolyte decomposition and a large difference in the work functions of the used metal oxides. The charge balanced device returns the specific capacitance of ~198 F g(-1) with corresponding specific energy of ~89 Wh kg(-1) at 1 A g(-1). The proposed composite systems have shown great potential in fabricating high performance supercapacitors.

Synthesis and processing of materials for direct thermal-to-electric energy conversion and storage

NASA Astrophysics Data System (ADS)

Thompson, Travis

Currently, fossil fuels are the primary source of energy. Mechanical heat engines convert the chemical potential energy in fossil fuels to useful electrical energy through combustion; a relatively low efficiency process that generates carbon dioxide. This practice has led to a significant increase in carbon dioxide emissions and is contributing to climate change. However, not all heat engines are mechanical. Alternative energy generation technologies to mechanical heat engines are known, yet underutilized. Thermoelectric generators are solid-state devices originally developed by NASA to power deep space spacecraft, which can also convert heat into electricity but without any moving parts. Similar to their mechanical counterparts, any heat source, including the burning of fossil fuels, can be used. However, clean heat sources, such as concentrated solar, can alternatively be used. Since the energy sources for many of the alternative energy technologies is intermittent, including concentrated solar for thermoelectric devices, load matching is difficult or impossible and an energy storage technology is needed in addition to the energy conversion technology. This increases the overall cost and complexity of the systems since two devices are required and represents a significant barrier for mass adoption of an alternative energy technology. However, it is possible to convert heat energy to electrical energy and store excess charge for use at a later time when the demand increases, in a single device. One such of a device is a thermogalvanic generator and is the electrochemical analog of electronic thermoelectric devices. Essentially, a thermogalvanic device represents the combination of thermoelectric and galvanic systems. As such, the rich history of strategies developed by both the thermoelectric community to better the performance of thermoelectric devices and by the electrochemical community to better traditional galvanic devices (i.e. batteries) can be applied to thermogalvanic devices. Although thermogalvanic devices are known, there has been little exploration into the use of thermogalvanic devices for power generation and energy storage. First, this work formalizes the energy problem and introduces the operating principles of thermoelectric, galvanic, and thermogalvanic devices. Second, oxide based thermoelectric materials are explored from a synthetic and processing standpoint. Out of necessity, a new synthetic technique was invented and a novel hot-press technique was developed. Third, a solid Li-ion conducting electrolyte, based on the garnet crystal structure, is identified for the use in a thermogalvanic cell. In order to better understand the conductivity behavior, an in-depth exploration into the variables that control the ionic transport is performed on the electrolyte. Third, a thermogalvanic cell is constructed using this garnet based Li-ion conducting solid electrolyte and the first demonstration of such a cell is presented. Finally, strategies to improve the performance of thermogalvanic cells based on garnet type solid electrolytes are outlined for future work. The purpose of this work is to use an interdisciplinary approach to marry together the electrochemistry of galvanic systems with the strategies used to better semiconductor based thermoelectric materials and ceramics processing techniques to fabricate these systems. This dissertation will explore the interplay of these areas.

Design, fabrication and characterization of a double layer solid oxide fuel cell (DLFC)

NASA Astrophysics Data System (ADS)

Wang, Guangjun; Wu, Xiangying; Cai, Yixiao; Ji, Yuan; Yaqub, Azra; Zhu, Bin

2016-11-01

A double layer solid oxide fuel cell (DLSOFC) without using the electrolyte (layer) has been designed by integrating advantages of positive electrode material of lithium ion battery(LiNi0.8Co0.15Al0.05O2) and oxygen-permeable membranes material (trace amount cobalt incorporated terbium doped ceria, TDC + Co) based on the semiconductor physics principle. Instead of using an electrolyte layer, the depletion layer between the anode and cathode served as an electronic insulator to block the electrons but to maintain the electrolyte function for ionic transport. Thus the device with two layers can realize the function of SOFC and at the same time avoids the electronic short circuiting problem. Such novel DLFC showed good performance at low temperatures, for instance, a maximum power density of 230 mWcm-2 was achieved at 500 °C. The working principle of the new device is presented.

Novel, Solvent Free, Single Ion Conductive Polymer Electrolytes (Warsaw-2001)

DTIC Science & Technology

2004-10-18

application in lithium and lithium - ion batteries , characterized by limited participation of anions in the transport of electrical charge. Studies...with studies on novel chemical energy conversion and storage devices mainly lithium or lithium ion batteries and fuel cells [1]. Our work within...this part of the project dealt with these novel ideas in the field of lithium or lithium - ion batteries based on polymeric solid electrolytes. The solid

Kinetic factors determining conducting filament formation in solid polymer electrolyte based planar devices

NASA Astrophysics Data System (ADS)

Krishnan, Karthik; Aono, Masakazu; Tsuruoka, Tohru

2016-07-01

Resistive switching characteristics and conducting filament formation dynamics in solid polymer electrolyte (SPE) based planar-type atomic switches, with opposing active Ag and inert Pt electrodes, have been investigated by optimizing the device configuration and experimental parameters such as the gap distance between the electrodes, the salt inclusion in the polymer matrix, and the compliance current applied in current-voltage measurements. The high ionic conductivities of SPE enabled us to make scanning electron microscopy observations of the filament formation processes in the sub-micrometer to micrometer ranges. It was found that switching behaviour and filament growth morphology depend strongly on several kinetic factors, such as the redox reaction rate at the electrode-polymer interfaces, ion mobility in the polymer matrix, electric field strength, and the reduction sites for precipitation. Different filament formations, resulting from unidirectional and dendritic growth behaviours, can be controlled by tuning specified parameters, which in turn improves the stability and performance of SPE-based devices.Resistive switching characteristics and conducting filament formation dynamics in solid polymer electrolyte (SPE) based planar-type atomic switches, with opposing active Ag and inert Pt electrodes, have been investigated by optimizing the device configuration and experimental parameters such as the gap distance between the electrodes, the salt inclusion in the polymer matrix, and the compliance current applied in current-voltage measurements. The high ionic conductivities of SPE enabled us to make scanning electron microscopy observations of the filament formation processes in the sub-micrometer to micrometer ranges. It was found that switching behaviour and filament growth morphology depend strongly on several kinetic factors, such as the redox reaction rate at the electrode-polymer interfaces, ion mobility in the polymer matrix, electric field strength, and the reduction sites for precipitation. Different filament formations, resulting from unidirectional and dendritic growth behaviours, can be controlled by tuning specified parameters, which in turn improves the stability and performance of SPE-based devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00569a

A high performance flexible all solid state supercapacitor based on the MnO2 sphere coated macro/mesoporous Ni/C electrode and ionic conducting electrolyte.

PubMed

Zhi, Jian; Reiser, Oliver; Wang, Youfu; Hu, Aiguo

2016-06-09

A high contact resistance between the active materials and the current collector, a low ionic conductivity of the gel electrolyte, and an impenetrable electrode structure are the three major barriers which greatly limit the capacitance of MnO2 in solid state supercapacitors. As a potential solution to these problems, in this work we report a novel electrode for solid state supercapacitors, based on a ternary system composed of hierarchical MnO2 spheres as the active material, macroporous Ni foam as gel penetrable skeletons and an ordered mesoporous carbon (OMC) membrane as the charge-transport accelerating layer. By employing butyl-3-methylimidazolium chloride (BMIMCl) modified gels as the ionic conducting electrolyte, the utilization efficiency of MnO2 on the specific capacitance was enhanced up to 88% of the theoretical value, delivering a volumetric capacitance of 81 F cm(-3), which is the highest value among MnO2 based solid state supercapacitors. Moreover, such a flexible device exhibits exceptional volumetric energy and power density (6.6 Wh L(-1) and 549 W L(-1), based on the whole device volume) combined with a small capacity loss of 8.5% after 6000 cycles under twisting. These encouraging findings unambiguously overcome the energy bottleneck of MnO2 in solid state supercapacitors, and open up a new application of macro/mesoporous materials in flexible devices.

A paper-based analytical device for the determination of hydrogen sulfide in fuel oils based on headspace liquid-phase microextraction and cyclic voltammetry.

PubMed

Nechaeva, Daria; Shishov, Andrey; Ermakov, Sergey; Bulatov, Andrey

2018-06-01

An easily performed miniaturized, cheap, selective and sensitive procedure for the determination of H 2 S in fuel oil samples based on a headspace liquid-phase microextraction followed by a cyclic voltammetry detection using a paper-based analytical device (PAD) was developed. A modified wax dipping method was applied to fabricate the PAD. The PAD included hydrophobic zones of sample and supporting electrolyte connecting by hydrophilic channel. The zones of sample and supporting electrolyte were connected with nickel working, platinum auxiliary and Ag/AgCl reference electrodes. The analytical procedure included separation of H 2 S from fuel oil sample based on the headspace liquid-phase microextraction in alkaline solution. Then, sulfide ions solution obtained and supporting electrolyte were dropped on the zones followed by analyte detection at + 0.45 V. Under the optimized conditions, H 2 S concentration in the range from 2 to 20 mg kg -1 had a good linear relation with the peak current. The limit of detection (3σ) was 0.6 mg kg -1 . The procedure was successfully applied to the analysis of fuel oil samples. Copyright © 2018 Elsevier B.V. All rights reserved.

High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes

NASA Astrophysics Data System (ADS)

Kim, Byungwoo; Chung, Haegeun; Kim, Woong

2012-04-01

We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ˜75 F g-1, ˜987 kW kg-1 and ˜27 W h kg-1, respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (˜158 F g-1) and energy density (˜53 W h kg-1). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices.

Synthesis and Characterization of Cellulose-Based Hydrogels to Be Used as Gel Electrolytes

PubMed Central

Navarra, Maria Assunta; Dal Bosco, Chiara; Serra Moreno, Judith; Vitucci, Francesco Maria; Paolone, Annalisa; Panero, Stefania

2015-01-01

Cellulose-based hydrogels, obtained by tuned, low-cost synthetic routes, are proposed as convenient gel electrolyte membranes. Hydrogels have been prepared from different types of cellulose by optimized solubilization and crosslinking steps. The obtained gel membranes have been characterized by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mechanical tests in order to investigate the crosslinking occurrence and modifications of cellulose resulting from the synthetic process, morphology of the hydrogels, their thermal stability, and viscoelastic-extensional properties, respectively. Hydrogels liquid uptake capability and ionic conductivity, derived from absorption of aqueous electrolytic solutions, have been evaluated, to assess the successful applicability of the proposed membranes as gel electrolytes for electrochemical devices. To this purpose, the redox behavior of electroactive species entrapped into the hydrogels has been investigated by cyclic voltammetry tests, revealing very high reversibility and ion diffusivity. PMID:26633528

High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes.

PubMed

Kim, Byungwoo; Chung, Haegeun; Kim, Woong

2012-04-20

We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ~75 F g(-1), ~987 kW kg(-1) and ~27 W h kg(-1), respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (~158 F g(-1)) and energy density (~53 W h kg(-1)). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices. © 2012 IOP Publishing Ltd

High conductivity electrolyte solutions and rechargeable cells incorporating such solutions

DOEpatents

Angell, C.A.; Zhang, S.S.; Xu, K.

1998-10-20

This invention relates generally to electrolyte solvents for use in liquid or rubbery polymer electrolyte solutions as are used, for example, in electrochemical devices. More specifically, this invention relates to sulfonyl/phospho-compound electrolyte solvents and sulfonyl/phospho-compound electrolyte solutions incorporating such solvents. 9 figs.

Basic investigation into the electrical performance of solid electrolyte membranes

NASA Technical Reports Server (NTRS)

Richter, R.

1982-01-01

The electrical performance of solid electrolyte membranes was investigated analytically and the results were compared with experimental data. It is concluded that in devices that are used for pumping oxygen the major power losses have to be attributed to the thin film electrodes. Relations were developed by which the effectiveness of tubular solid electrolyte membranes can be determined and the optimum length evaluated. The observed failure of solid electrolyte tube membranes in very localized areas is explained by the highly non-uniform current distribution in the membranes. The analysis points to a possible contact resistance between the electrodes and the solid electrolyte material. This possible contact resistance remains to be investigated experimentally. It is concluded that film electrodes are not appropriate for devices which operate with current flow, i.e., pumps though they can be employed without reservation in devices that measure oxygen pressures if a limited increase in the response time can be tolerated.

Hydrogen generation by electrolysis of aqueous organic solutions

NASA Technical Reports Server (NTRS)

Jeffries-Nakamura, Barbara (Inventor); Narayanan, Sekharipuram R. (Inventor); Chun, William (Inventor); Valdez, Thomas I. (Inventor)

2006-01-01

A device for electrolysis of an aqueous solution of an organic fuel. The electrolyte is a solid-state polymer membrane with anode and cathode catalysts on both surfaces for electro-oxidization and electro-reduction. A low-cost and portable hydrogen generator can be made based on the device with organic fuels such as methanol.

Hydrogen generation by electrolysis of aqueous organic solutions

NASA Technical Reports Server (NTRS)

Narayanan, Sekharipuram R. (Inventor); Chun, William (Inventor); Jeffries-Nakamura, Barbara (Inventor); Valdez, Thomas I. (Inventor)

2002-01-01

A device for electrolysis of an aqueous solution of an organic fuel. The electrolyte is a solid-state polymer membrane with anode and cathode catalysts on both surfaces for electro-oxidization and electro-reduction. A low-cost and portable hydrogen generator can be made based on the device with organic fuels such as methanol.

Three-dimensional ionic conduction in the strained electrolytes of solid oxide fuel cells

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

Han, Yupei; Zou, Minda; Lv, Weiqiang

2016-05-07

Flexible power sources including fuel cells and batteries are the key to realizing flexible electronic devices with pronounced foldability. To understand the bending effects in these devices, theoretical analysis on three-dimensional (3-D) lattice bending is necessary. In this report, we derive a 3-D analytical model to analyze the effects of electrolyte crystal bending on ionic conductivity in flexible solid-state batteries/fuel cells. By employing solid oxide fuel cells as a materials' platform, the intrinsic parameters of bent electrolyte materials, including lattice constant, Young's modulus, and Poisson ratio, are evaluated. Our work facilitates the rational design of highly efficient flexible electrolytes formore » high-performance flexible device applications.« less

Physical Organic Approach to Persistent, Cyclable, Low-Potential Electrolytes for Flow Battery Applications.

PubMed

Sevov, Christo S; Hickey, David P; Cook, Monique E; Robinson, Sophia G; Barnett, Shoshanna; Minteer, Shelley D; Sigman, Matthew S; Sanford, Melanie S

2017-03-01

The deployment of nonaqueous redox flow batteries for grid-scale energy storage has been impeded by a lack of electrolytes that undergo redox events at as low (anolyte) or high (catholyte) potentials as possible while exhibiting the stability and cycling lifetimes necessary for a battery device. Herein, we report a new approach to electrolyte design that uses physical organic tools for the predictive targeting of electrolytes that possess this combination of properties. We apply this approach to the identification of a new pyridinium-based anolyte that undergoes 1e - electrochemical charge-discharge cycling at low potential (-1.21 V vs Fc/Fc + ) to a 95% state-of-charge without detectable capacity loss after 200 cycles.

Molecularly Engineered Ru(II) Sensitizers Compatible with Cobalt(II/III) Redox Mediators for Dye-Sensitized Solar Cells.

PubMed

Wu, Kuan-Lin; Huckaba, Aron J; Clifford, John N; Yang, Ya-Wen; Yella, Aswani; Palomares, Emilio; Grätzel, Michael; Chi, Yun; Nazeeruddin, Mohammad Khaja

2016-08-01

Thiocyanate-free isoquinazolylpyrazolate Ru(II) complexes were synthesized and applied as sensitizers in dye-sensitized solar cells (DSCs). Unlike most other successful Ru sensitizers, Co-based electrolytes were used, and resulting record efficiency of 9.53% was obtained under simulated sunlight with an intensity of 100 mW cm(-2). Specifically, dye 51-57dht.1 and an electrolyte based on Co(phen)3 led to measurement of a JSC of 13.89 mA cm(-2), VOC of 900 mV, and FF of 0.762 to yield 9.53% efficiency. The improved device performances were achieved by the inclusion of 2-hexylthiophene units onto the isoquinoline subunits, in addition to lengthening the perfluoroalkyl chain on the pyrazolate chelating group, which worked to increase light absorption and decrease recombination effects when using the Co-based electrolyte. As this study shows, Ru(II) sensitizers bearing sterically demanding ligands can allow successful utilization of important Co electrolytes and high performance.

Low temperature double-layer capacitors

NASA Technical Reports Server (NTRS)

Brandon, Erik J. (Inventor); West, William C. (Inventor); Smart, Marshall C. (Inventor)

2011-01-01

Double-layer capacitors capable of operating at extremely low temperatures (e.g., as low as -75.degree. C.) are disclosed. Electrolyte solutions combining a base solvent (e.g., acetonitrile) and a cosolvent are employed to lower the melting point of the base electrolyte. Example cosolvents include methyl formate, ethyl acetate, methyl acetate, propionitrile, butyronitrile, and 1,3-dioxolane. An optimized concentration (e.g., 0.10 M to 0.75 M) of salt, such as tetraethylammonium tetrafluoroborate, is dissolved into the electrolyte solution. In some cases (e.g., 1,3-dioxolane cosolvent) additives, such as 2% by volume triethylamine, may be included in the solvent mixture to prevent polymerization of the solution. Conventional device form factors and structural elements (e.g., porous carbon electrodes and a polyethylene separator) may be employed.

Sodium-oxygen batteries with alkyl-carbonate and ether based electrolytes.

PubMed

Kim, Jinsoo; Lim, Hee-Dae; Gwon, Hyeokjo; Kang, Kisuk

2013-03-14

Recently, metal-air batteries, such as lithium-air and zinc-air systems, have been studied extensively as potential candidates for ultra-high energy density storage devices because of their exceptionally high capacities. Here, we report such an electrochemical system based on sodium, which is abundant and inexpensive. Two types of sodium-oxygen batteries were introduced and studied, i.e. with carbonate and non-carbonate electrolytes. Both types could deliver specific capacities (2800 and 6000 mA h g(-1)) comparable to that of lithium-oxygen batteries but with slightly lower discharge voltages (2.3 V and 2.0 V). The reaction mechanisms of sodium-oxygen batteries in carbonate and non-carbonate electrolytes were investigated and compared with those of lithium-oxygen batteries.

Rational design of new electrolyte materials for electrochemical double layer capacitors

NASA Astrophysics Data System (ADS)

Schütter, Christoph; Husch, Tamara; Viswanathan, Venkatasubramanian; Passerini, Stefano; Balducci, Andrea; Korth, Martin

2016-09-01

The development of new electrolytes is a centerpiece of many strategies to improve electrochemical double layer capacitor (EDLC) devices. We present here a computational screening-based rational design approach to find new electrolyte materials. As an example application, the known chemical space of almost 70 million compounds is investigated in search of electrochemically more stable solvents. Cyano esters are identified as especially promising new compound class. Theoretical predictions are validated with subsequent experimental studies on a selected case. These studies show that based on theoretical predictions only, a previously untested, but very well performing compound class was identified. We thus find that our rational design strategy is indeed able to successfully identify completely new materials with substantially improved properties.

Low Temperature Double-Layer Capacitors Using Asymmetric and Spiro-Type Quaternary Ammonium Salts

NASA Technical Reports Server (NTRS)

Smart, Marshall C. (Inventor); Brandon, Erik J. (Inventor); West, William C. (Inventor)

2014-01-01

Double-layer capacitors capable of operating at extremely low temperatures (e.g., as low as -80.degree. C.) are disclosed. Electrolyte solutions combining a base solvent (e.g., acetonitrile) and a cosolvent are employed to lower the melting point of the base electrolyte. Example cosolvents include methyl formate, ethyl acetate, methyl acetate, propionitrile, butyronitrile, and 1,3-dioxolane. A quaternary ammonium salt including at least one of triethylmethylammonium tetrafluoroborate (TEMATFB) and spiro-(1,1')-bipyrrolidium tetrafluoroborate (SBPBF.sub.4), is used in an optimized concentration (e.g., 0.10 M to 0.75 M), dissolved into the electrolyte solution. Conventional device form factors and structural elements (e.g., porous carbon electrodes and a polyethylene separator) may be employed.

Electrolyte and composition effects on the performances of asymmetric supercapacitors constructed with Mn3O4 nanoparticles-graphene nanocomposites

NASA Astrophysics Data System (ADS)

Xiao, Yuanhua; Cao, Yongbo; Gong, Yuyin; Zhang, Aiqin; Zhao, Jihong; Fang, Shaoming; Jia, Dianzeng; Li, Feng

2014-01-01

Nanocomposites of Mn3O4 nanoparticles and graphene (GR) nanosheets - Mn3O4@GR can be made by growing Mn3O4 nanoparticles directly on the surfaces of GR in solvothermal reactions. The asymmetric supercapacitors constructed with Mn3O4@GR as positive and activated carbon (AC) as negative electrodes, respectively, show highly enhanced performances in energy storage. It was found that the electrolytes employed in constructing electrodes of the devices can influence the performances of Mn3O4@GR supercapacitors dramatically. Compared to their energy density in KOH electrolyte, the devices exhibit improved charge storage performances in Na2SO4 electrolyte. Furthermore, the charge storage abilities of the devices are closely related to the amount of Mn3O4 nanoparticles loaded onto the surface of GR nanosheets. The performances of Mn3O4@GR//AC asymmetric supercapacitors can be optimized by carefully tailoring the composition of electrode materials and adjusting the electrolytes for making the devices.

Preparation of redox polymer cathodes for thin film rechargeable batteries

DOEpatents

Skotheim, T.A.; Lee, H.S.; Okamoto, Yoshiyuki.

1994-11-08

The present invention relates to the manufacture of thin film solid state electrochemical devices using composite cathodes comprising a redox polymer capable of undergoing oxidation and reduction, a polymer solid electrolyte and conducting carbon. The polymeric cathode material is formed as a composite of radiation crosslinked polymer electrolytes and radiation crosslinked redox polymers based on polysiloxane backbones with attached organosulfur side groups capable of forming sulfur-sulfur bonds during electrochemical oxidation.

Electrochemistry serving people and nature: high-energy ecocapacitors based on redox-active electrolytes.

PubMed

Frackowiak, Elzbieta; Fic, Krzysztof; Meller, Mikolaj; Lota, Grzegorz

2012-07-01

Positive Poles: A new type of electrochemical capacitor with two different aqueous solutions, separated by a Nafion membrane is described. High capacitance values as well as excellent energy/power characteristics are reported and discussed. The neutral character of the applied electrolytes makes this capacitor an environmentally friendly, easy to assemble, and cost-effective device for energy storage. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Paper-based microfluidic system for tear electrolyte analysis† †We declare no competing financial interests. ‡ ‡Electronic supplementary information (ESI) available: Microscopic images of G1 paper and G41 paper under brightfield; optimization of CO2 laser radiation fluence and beam speed for ablating filter paper-G1; photographs of DI water diffusion in microfluidic channels with different lengths, different widths, different viscosities of fluid and different numbers of channels; fluorescence intensity readouts of Na+ and K+ ions with varied concentrations of fluorescent probes; effect of variations in temperature on fluorescence intensity; photographs of DMSO on G1 paper dried in the air; calibration curves of electrolyte sensing on G1 paper using microplate reader measurement; calculation of sensitivity of the fluorescent sensors based on International Union of Pure and Applied Chemistry (IUPAC) guidelines; quantification of ion interference in buffer solution and artificial tear fluid; light attenuation of LED lights using different optical filters; the design of the sample collection device and its potential clinical use; calibration curves of electrolyte sensors using the paper-based microfluidic system; quantifications of evaporation effect on sampling process; design of the sample collection device and its potential clinical use; batch-to-batch variation experiments; equation for background subtraction; movies of sample collection and measurements. See DOI: 10.1039/c6lc01450j Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file.

PubMed Central

Jiang, Nan; Tamayol, Ali; Ruiz-Esparza, Guillermo U.; Zhang, Yu Shrike; Medina-Pando, Sofía; Gupta, Aditi; Wolffsohn, James S.; Butt, Haider; Khademhosseini, Ali

2017-01-01

The analysis of tear constituents at point-of-care settings has a potential for early diagnosis of ocular disorders such as dry eye disease, low-cost screening, and surveillance of at-risk subjects. However, current minimally-invasive rapid tear analysis systems for point-of-care settings have been limited to assessment of osmolarity or inflammatory markers and cannot differentiate between dry eye subclassifications. Here, we demonstrate a portable microfluidic system that allows quantitative analysis of electrolytes in the tear fluid that is suited for point-of-care settings. The microfluidic system consists of a capillary tube for sample collection, a reservoir for sample dilution, and a paper-based microfluidic device for electrolyte analysis. The sensing regions are functionalized with fluorescent crown ethers, o-acetanisidide, and seminaphtorhodafluor that are sensitive to mono- and divalent electrolytes, and their fluorescence outputs are measured with a smartphone readout device. The measured sensitivity values of Na+, K+, Ca2+ ions and pH in artificial tear fluid were matched with the known ion concentrations within the physiological range. The microfluidic system was tested with samples having different ionic concentrations, demonstrating the feasibility for the detection of early-stage dry eye, differential diagnosis of dry eye sub-types, and their severity staging. PMID:28207920

Highly transparent supercapacitors based on ZnO/MnO2 nanostructures.

PubMed

Borysiewicz, M A; Ekielski, M; Ogorzałek, Z; Wzorek, M; Kaczmarski, J; Wojciechowski, T

2017-06-08

The recent rapid development of transparent electronics, notably displays and control circuits, requires the development of highly transparent energy storage devices, such as supercapacitors. The devices reported to date utilize carbon-based electrodes for high performance, however at the cost of their low transparency around 50%, insufficient for real transparent devices. To overcome this obstacle, in this communication highly transparent supercapacitors were fabricated based on ZnO/MnO 2 nanostructured electrodes. ZnO served as an intrinsically transparent skeleton for increasing the electrode surface, while MnO 2 nanoparticles were applied for high capacitance. Two MnO 2 synthesis routes were followed, based on the reaction of KMnO 4 with Mn(Ac) 2 and PAH, leading to the synthesis of β-MnO 2 with minority α-MnO 2 nanoparticles and amorphous MnO 2 with embedded β-MnO 2 , respectively. The devices based on such electrodes showed high capacitances of 2.6 mF cm -2 and 1.6 mF cm -2 , respectively, at a scan rate of 1 mV s -1 and capacitances of 104 μF cm -2 and 204 μF cm -2 at a very high rate of 1 V s -1 , not studied for transparent supercapacitors previously. Additionally, the Mn(Ac) 2 devices exhibited very high transparencies of 86% vs. air, far superior to other transparent energy storage devices reported with similar charge storage properties. This high device performance was achieved with a non-acidic LiCl gel electrolyte, reducing corrosion and handling risks associated with conventional highly concentrated acidic electrolytes, enabling applications in safe, wearable, transparent devices.

A Highly Flexible Supercapacitor Based on MnO2/RGO Nanosheets and Bacterial Cellulose-Filled Gel Electrolyte

PubMed Central

Fei, Haojie; Saha, Nabanita; Kazantseva, Natalia; Moucka, Robert; Cheng, Qilin; Saha, Petr

2017-01-01

The flexible supercapacitors (SCs) of the conventional sandwich-type structure have poor flexibility due to the large thickness of the final entire device. Herein, we have fabricated a highly flexible asymmetric SC using manganese dioxide (MnO2) and reduced graphene oxide (RGO) nanosheet-piled hydrogel films and a novel bacterial cellulose (BC)-filled polyacrylic acid sodium salt-Na2SO4 (BC/PAAS-Na2SO4) neutral gel electrolyte. Apart from being environmentally friendly, this BC/PAAS-Na2SO4 gel electrolyte has high viscosity and a sticky property, which enables it to combine two electrodes together. Meanwhile, the intertangling of the filled BC in the gel electrolyte hinders the decrease of the viscosity with temperature, and forms a separator to prevent the two electrodes from short-circuiting. Using these materials, the total thickness of the fabricated device does not exceed 120 μm. This SC device demonstrates high flexibility, where bending and even rolling have no obvious effect on the electrochemical performance. In addition, owing to the asymmetric configuration, the cell voltage of this flexible SC has been extended to 1.8 V, and the energy density can reach up to 11.7 Wh kg−1 at the power density of 441 W kg−1. This SC also exhibits a good cycling stability, with a capacitance retention of 85.5% over 5000 cycles. PMID:29084177

Structural and electrical characterization of tamarind seed polysaccharide (TSP) doped with NH4HCO2

NASA Astrophysics Data System (ADS)

Premalatha, M.; Mathavan, T.; Selvasekarapandian, S.; Selvalakshmi, S.

2018-04-01

In the modern era, development of electrochemical energy devices such as batteries, fuel cells and supercapacitors gain attention due to the deficiency of renewable energy resources. More specifically, proton conducting materials create prime interest in the development of electrochemical devices. In this regards, a novel proton conducting biopolymer electrolyte based on Tamarind Seed Polysaccharide (TSP) was synthesized with different concentration of ammonium formate (NH4HCO2). The amorphous nature of the polymer electrolytes has been identified by XRD technique. The observed ionic conductivity values reveal that the biopolymer containing 1 g TSP: 0.4 g NH4HCO2 has highest ionic conductivity 1.23×10-3 S cm-1.

Significant Performance Enhancement in Asymmetric Supercapacitors based on Metal Oxides, Carbon nanotubes and Neutral Aqueous Electrolyte

PubMed Central

Singh, Arvinder; Chandra, Amreesh

2015-01-01

Amongst the materials being investigated for supercapacitor electrodes, carbon based materials are most investigated. However, pure carbon materials suffer from inherent physical processes which limit the maximum specific energy and power that can be achieved in an energy storage device. Therefore, use of carbon-based composites with suitable nano-materials is attaining prominence. The synergistic effect between the pseudocapacitive nanomaterials (high specific energy) and carbon (high specific power) is expected to deliver the desired improvements. We report the fabrication of high capacitance asymmetric supercapacitor based on electrodes of composites of SnO2 and V2O5 with multiwall carbon nanotubes and neutral 0.5 M Li2SO4 aqueous electrolyte. The advantages of the fabricated asymmetric supercapacitors are compared with the results published in the literature. The widened operating voltage window is due to the higher over-potential of electrolyte decomposition and a large difference in the work functions of the used metal oxides. The charge balanced device returns the specific capacitance of ~198 F g−1 with corresponding specific energy of ~89 Wh kg−1 at 1 A g−1. The proposed composite systems have shown great potential in fabricating high performance supercapacitors. PMID:26494197

Significant Performance Enhancement in Asymmetric Supercapacitors based on Metal Oxides, Carbon nanotubes and Neutral Aqueous Electrolyte

NASA Astrophysics Data System (ADS)

Singh, Arvinder; Chandra, Amreesh

2015-10-01

Amongst the materials being investigated for supercapacitor electrodes, carbon based materials are most investigated. However, pure carbon materials suffer from inherent physical processes which limit the maximum specific energy and power that can be achieved in an energy storage device. Therefore, use of carbon-based composites with suitable nano-materials is attaining prominence. The synergistic effect between the pseudocapacitive nanomaterials (high specific energy) and carbon (high specific power) is expected to deliver the desired improvements. We report the fabrication of high capacitance asymmetric supercapacitor based on electrodes of composites of SnO2 and V2O5 with multiwall carbon nanotubes and neutral 0.5 M Li2SO4 aqueous electrolyte. The advantages of the fabricated asymmetric supercapacitors are compared with the results published in the literature. The widened operating voltage window is due to the higher over-potential of electrolyte decomposition and a large difference in the work functions of the used metal oxides. The charge balanced device returns the specific capacitance of ~198 F g-1 with corresponding specific energy of ~89 Wh kg-1 at 1 A g-1. The proposed composite systems have shown great potential in fabricating high performance supercapacitors.

Quasi-solid state electrolyte for semi-transparent bifacial dye-sensitized solar cell with over 10% power conversion efficiency

NASA Astrophysics Data System (ADS)

Hwang, Dae-Kue; Nam, Jung Eun; Jo, Hyo Jeong; Sung, Shi-Joon

2017-09-01

In traditional dye-sensitized solar cells (DSSCs), the liquid electrolyte (LE) presents a problem for long-term stability. Herein, we demonstrate a bifacial DSSC by combining a new metal-free organic dye and a quasi-solid state electrolyte (QSSE) that contains poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP)-based polymer gel. The incident light irradiates the front side of the DSSC, and the transmitted light is reused after reflection on the back side. Owing to the semi-transparent DSSC electrode, the reflected light can penetrate and be absorbed by the dye molecules in the DSSC, thereby enhancing the short-circuit current density and thus the overall power conversion efficiency (PCE). The PCE for the DSSC device with QSSE from bifacial irradiation is 10.37%, a value that is comparable to that obtained with LE-based DSSC (9.89%). The stability of the device is enhanced when the polymer gel containing PVdF-HFP is mixed with the LE, and the effectiveness of PVdF-HFP as a gelator is attributed to its interaction with the Li+ ions. Based on our preliminary results, this architecture can lead to more stable bifacial QSSE-based DSSCs without sacrificing the photovoltaic performance.

Methods for solid electrolyte interphase formation and anode pre-lithiation of lithium ion capacitors

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

Raman, Santhanam; Xi, Xiaomei; Ye, Xiang-Rong

A method of pre-doping an anode of an energy storage device can include immersing the anode and a dopant source in an electrolyte, and coupling a substantially constant current between the anode and the dopant source. A method of pre-doping an anode of an energy storage device can include immersing the anode and a dopant source in an electrolyte, and coupling a substantially constant voltage across the anode and the dopant source. An energy storage device can include an anode having a lithium ion pre-doping level of about 60% to about 90%.

High Power Electric Double-Layer Capacitors based on Room-Temperature Ionic Liquids and Nanostructured Carbons

NASA Astrophysics Data System (ADS)

Perez, Carlos R.

The efficient storage of electrical energy constitutes both a fundamental challenge for 21st century science and an urgent requirement for the sustainability of our technological civilization. The push for cleaner renewable forms of energy production, such as solar and wind power, strongly depends on a concomitant development of suitable storage methods to pair with these intermittent sources, as well as for mobile applications, such as vehicles and personal electronics. In this regard, Electrochemical Double-Layer Capacitors (supercapacitors) represent a vibrant area of research due to their environmental friendliness, long lifetimes, high power capability, and relative underdevelopment when compared to electrochemical batteries. Currently supercapacitors have gravimetric energies one order of magnitude lower than similarly advanced batteries, while conversly enjoying a similar advantage over them in terms of power. The challenge is to increase the gravimentric energies and conserve the high power. On the material side, research focuses on highly porous supports and electrolytes, the critical components of supercapacitors. Through the use of electrolyte systems with a wider electrochemical stability window, as well as properly tailored carbon nanomaterials as electrodes, significant improvements in performance are possible. Room Temperature Ionic Liquids and Carbide-Derived Carbons are promising electrolytes and electrodes, respectively. RTILs have been shown to be stable at up to twice the voltage of organic solvent-salt systems currently employed in supercapacitors, and CDCs are tunable in pore structure, show good electrical conductivity, and superior demonstrated capability as electrode material. This work aims to better understand the interplay of electrode and electrolyte parameters, such as pore structure and ion size, in the ultimate performance of RTIL-based supercapacitors in terms of power, energy, and temperature of operation. For this purpose, carbon nanomaterials such as nanoporous CDC nanopowders, vertically aligned carbon nanotube arrays, and single wall carbon nanotube aerogels, were synthesized and used as electrodes, alongside RTIL electrolytes with systematically varying ion sizes and compositions. While electrode/electrolyte development can take place along parallel lines, both must be properly matched to the device's ultimate operating conditions and specific application. The resulting devices exhibit good performance characteristics, and the best temperature range of any electrochemical storage device to date.

Investigation of Novel Electrolytes for Use in Lithium-Ion Batteries and Direct Methanol Fuel Cells

NASA Astrophysics Data System (ADS)

Pilar, Kartik

Energy storage and conversion plays a critical role in the efficient use of available energy and is crucial for the utilization of renewable energy sources. To achieve maximum efficiency of renewable energy sources, improvements to energy storage materials must be developed. In this work, novel electrolytes for secondary batteries and fuel cells have been studied using nuclear magnetic resonance and high pressure x-ray scattering techniques to form a better understanding of dynamic and structural properties of these materials. Ionic liquids have been studied due to their potential as a safer alternative to organic solvent-based electrolytes in lithium-ion batteries and composite sulfonated polyetheretherketone (sPEEK) membranes have been investigated for their potential use as a proton exchange membrane electrolyte in direct methanol fuel cells. The characterization of these novel electrolytes is a step towards the development of the next generation of improved energy storage and energy conversion devices.

Novel Stable Gel Polymer Electrolyte: Toward a High Safety and Long Life Li-Air Battery.

PubMed

Yi, Jin; Liu, Xizheng; Guo, Shaohua; Zhu, Kai; Xue, Hailong; Zhou, Haoshen

2015-10-28

Nonaqueous Li-air battery, as a promising electrochemical energy storage device, has attracted substantial interest, while the safety issues derived from the intrinsic instability of organic liquid electrolytes may become a possible bottleneck for the future application of Li-air battery. Herein, through elaborate design, a novel stable composite gel polymer electrolyte is first proposed and explored for Li-air battery. By use of the composite gel polymer electrolyte, the Li-air polymer batteries composed of a lithium foil anode and Super P cathode are assembled and operated in ambient air and their cycling performance is evaluated. The batteries exhibit enhanced cycling stability and safety, where 100 cycles are achieved in ambient air at room temperature. The feasibility study demonstrates that the gel polymer electrolyte-based polymer Li-air battery is highly advantageous and could be used as a useful alternative strategy for the development of Li-air battery upon further application.

A Hybrid Redox-Supercapacitor System with Anionic Catholyte and Cationic Anolyte

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

Wang, B; Macia-Agullo, JA; Prendiville, DG

A significant challenge for energy storage technologies is to realize battery-level energy density and capacitor-level durability and power density in one device. By introducing an electrolyte composed of an anionic catholyte and a cationic anolyte into a symmetric carbon-based supercapacitor configuration, a hybrid electrochemical battery-supercapacitor system using soluble redox species delivers significantly improved energy density from 20 to 42 W.h/kg (based on the electrode mass) and stable capacities for > 10(4) cycles. The ionic species formed in the electrolyte are studied by UV-Vis, Raman and mass spectroscopy to probe the energy storage mechanism. The strategy is general and may providemore » a route to critically-needed fast-charging devices with both high energy density and power. (C) 2014 The Electrochemical Society. All rights reserved.« less

Comparison of starch and gelatin hydrogels for non-toxic supercapacitor electrolytes

NASA Astrophysics Data System (ADS)

Railanmaa, Anna; Lehtimäki, Suvi; Lupo, Donald

2017-06-01

Starch and gelatin are two of the most abundantly available natural polymers. Their non-toxicity, low cost, and compatibility with aqueous solvents make them ideal for use in ubiquitous, environmentally friendly electronics systems. This work presents the results of conductivity measurements through impedance spectroscopy for gelatin- and starch-based aqueous gel electrolytes. The NaCl-based gels were physically cross-linked. The conductivity values were 84.6 mS/cm at 1.5 mol L-1 and 71.5 mS/cm at 2 mol L-1 for gelatin and starch, respectively. The mechanical properties of gelatin were found preferable to those of starch, although they deteriorated significantly when the salt concentration exceeded 2 mol L-1. The ability of the gels to successfully act as a supercapacitor electrolyte was demonstrated with printed electrodes on plastic substrate. The devices were characterized through cyclic voltammetry measurements. The results imply that these polymer gel electrolytes are very promising for replacing the traditional aqueous liquid electrolytes in supercapacitors in applications where, for example, user and environmental safety is essential.

Poly-4-vinylphenol (PVP) and Poly(melamine-co-formaldehyde) (PMF)-Based Atomic Switching Device and Its Application to Logic Gate Circuits with Low Operating Voltage.

PubMed

Kang, Dong-Ho; Choi, Woo-Young; Woo, Hyunsuk; Jang, Sungkyu; Park, Hyung-Youl; Shim, Jaewoo; Choi, Jae-Woong; Kim, Sungho; Jeon, Sanghun; Lee, Sungjoo; Park, Jin-Hong

2017-08-16

In this study, we demonstrate a high-performance solid polymer electrolyte (SPE) atomic switching device with low SET/RESET voltages (0.25 and -0.5 V, respectively), high on/off-current ratio (10 5 ), excellent cyclic endurance (>10 3 ), and long retention time (>10 4 s), where poly-4-vinylphenol (PVP)/poly(melamine-co-formaldehyde) (PMF) is used as an SPE layer. To accomplish these excellent device performance parameters, we reduce the off-current level of the PVP/PMF atomic switching device by improving the electrical insulating property of the PVP/PMF electrolyte through adjustment of the number of cross-linked chains. We then apply a titanium buffer layer to the PVP/PMF switching device for further improvement of bipolar switching behavior and device stability. In addition, we first implement SPE atomic switch-based logic AND and OR circuits with low operating voltages below 2 V by integrating 5 × 5 arrays of PVP/PMF switching devices on the flexible substrate. In particular, this low operating voltage of our logic circuits was much lower than that (>5 V) of the circuits configured by polymer resistive random access memory. This research successfully presents the feasibility of PVP/PMF atomic switches for flexible integrated circuits for next-generation electronic applications.

Design rules and reality check for carbon-based ultracapacitors

NASA Astrophysics Data System (ADS)

Eisenmann, Erhard T.

1995-04-01

Design criteria for carbon-based Ultracapacitors have been determined for specified energy and power requirements, using the geometry of the components and such material properties as density, porosity and conductivity as parameters, while also considering chemical compatibility. This analysis shows that the weights of active and inactive components of the capacitor structure must be carefully balanced for maximum energy and power density. When applied to nonaqueous electrolytes, the design rules for a 5 Wh/kg device call for porous carbon with a specific capacitance of about 30 F/cu cm. This performance is not achievable with pure, electrostatic double layer capacitance. Double layer capacitance is only 5 to 30% of that observed in aqueous electrolyte. Tests also showed that nonaqueous electrolytes have a diminished capability to access micropores in activated carbon, in one case yielding a capacitance of less than 1 F/cu cm for carbon that had 100 F/cu cm in aqueous electrolyte. With negative results on nonaqueous electrolytes dominating the present study, the obvious conclusion is to concentrate on aqueous systems. Only aqueous double layer capacitors offer adequate electrostatic charging characteristics which is the basis for high power performance. There arc many opportunities for further advancing aqueous double layer capacitors, one being the use of highly activated carbon films, as opposed to powders, fibers and foams. While the manufacture of carbon films is still costly, and while the energy and power density of the resulting devices may not meet the optimistic goals that have been proposed, this technology could produce true double layer capacitors with significantly improved performance and large commercial potential.

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

Wu, Chun-Lan; Yuan, Hongtao; Li, Yanbin

Electric-double-layer (EDL) gating with liquid electrolyte has been a powerful tool widely used to explore emerging interfacial electronic phenomena. Due to the large EDL capacitance, a high carrier density up to 10 14 cm –2 can be induced, directly leading to the realization of field-induced insulator to metal (or superconductor) transition. However, the liquid nature of the electrolyte has created technical issues including possible side electrochemical reactions or intercalation, and the potential for huge strain at the interface during cooling. In addition, the liquid coverage of active devices also makes many surface characterizations and in situ measurements challenging. Here, wemore » demonstrate an all solid-state EDL device based on a solid superionic conductor LaF 3, which can be used as both a substrate and a fluorine ionic gate dielectric to achieve a wide tunability of carrier density without the issues of strain or electrochemical reactions and can expose the active device surface for external access. Based on LaF 3 EDL transistors (EDLTs), we observe the metal–insulator transition in MoS 2. Interestingly, the well-defined crystal lattice provides a more uniform potential distribution in the substrate, resulting in less interface electron scattering and therefore a higher mobility in MoS 2 transistors. Finally, this result shows the powerful gating capability of LaF 3 solid electrolyte for new possibilities of novel interfacial electronic phenomena.« less

Durable electrooptic devices comprising ionic liquids

DOEpatents

Burrell, Anthony K [Los Alamos, NM; Agrawal, Anoop [Tucson, AZ; Cronin,; John, P [Tucson, AZ; Tonazzi, Juan C. L. [Tucson, AZ; Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM

2009-12-15

Electrolyte solutions for electrochromic devices such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes. Some of the electrolyte solutions color to red when devices employing the solutions are powered, leading to red or neutral electrooptic devices.

Durable Electrooptic Devices Comprising Ionic Liquids

DOEpatents

Burrell, Anthony K.; Agrawal, Anoop; Cronin, John P.; Tonazzi, Juan C. L.; Warner, Benjamin P.; McCleskey, T. Mark

2008-11-11

Electrolyte solutions for electrochromic devices such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes. Some of the electrolyte solutions color to red when devices employing the solutions are powered, leading to red or neutral electrooptic devices.

Photoelectrochemical cells for conversion of solar energy to electricity and methods of their manufacture

DOEpatents

Skotheim, Terje

1984-04-10

A photoelectric device is disclosed which comprises first and second layers of semiconductive material, each of a different bandgap, with a layer of dry solid polymer electrolyte disposed between the two semiconductor layers. A layer of a polymer blend of a highly conductive polymer and a solid polymer electrolyte is further interposed between the dry solid polymer electrolyte and the first semiconductor layer. A method of manufacturing such devices is also disclosed.

Spectroscopic detection of halogen bonding resolves dye regeneration in the dye-sensitized solar cell.

PubMed

Parlane, Fraser G L; Mustoe, Chantal; Kellett, Cameron W; Simon, Sarah J; Swords, Wesley B; Meyer, Gerald J; Kennepohl, Pierre; Berlinguette, Curtis P

2017-11-24

The interactions between a surface-adsorbed dye and a soluble redox-active electrolyte species in the dye-sensitized solar cell has a significant impact on the rate of regeneration of photo-oxidized dye molecules and open-circuit voltage of the device. Dyes must therefore be designed to encourage these interfacial interactions, but experimentally resolving how such weak interactions affect electron transfer is challenging. Herein, we use X-ray absorption spectroscopy to confirm halogen bonding can exist at the dye-electrolyte interface. Using a known series of triphenylamine-based dyes bearing halogen substituents geometrically positioned for reaction with halides in solution, halogen bonding was detected only in cases where brominated and iodinated dyes were photo-oxidized. This result implies that weak intermolecular interactions between photo-oxidized dyes and the electrolyte can impact device photovoltages. This result was unexpected considering the low concentration of oxidized dyes (less than 1 in 100,000) under full solar illumination.

Energy storage device including a redox-enhanced electrolyte

DOEpatents

Stucky, Galen; Evanko, Brian; Parker, Nicholas; Vonlanthen, David; Auston, David; Boettcher, Shannon; Chun, Sang-Eun; Ji, Xiulei; Wang, Bao; Wang, Xingfeng; Chandrabose, Raghu Subash

2017-08-08

An electrical double layer capacitor (EDLC) energy storage device is provided that includes at least two electrodes and a redox-enhanced electrolyte including two redox couples such that there is a different one of the redox couples for each of the electrodes. When charged, the charge is stored in Faradaic reactions with the at least two redox couples in the electrolyte and in a double-layer capacitance of a porous carbon material that comprises at least one of the electrodes, and a self-discharge of the energy storage device is mitigated by at least one of electrostatic attraction, adsorption, physisorption, and chemisorption of a redox couple onto the porous carbon material.

A Model-based Prognostics Methodology for Electrolytic Capacitors Based on Electrical Overstress Accelerated Aging

NASA Technical Reports Server (NTRS)

Celaya, Jose; Kulkarni, Chetan; Biswas, Gautam; Saha, Sankalita; Goebel, Kai

2011-01-01

A remaining useful life prediction methodology for electrolytic capacitors is presented. This methodology is based on the Kalman filter framework and an empirical degradation model. Electrolytic capacitors are used in several applications ranging from power supplies on critical avionics equipment to power drivers for electro-mechanical actuators. These devices are known for their comparatively low reliability and given their criticality in electronics subsystems they are a good candidate for component level prognostics and health management. Prognostics provides a way to assess remaining useful life of a capacitor based on its current state of health and its anticipated future usage and operational conditions. We present here also, experimental results of an accelerated aging test under electrical stresses. The data obtained in this test form the basis for a remaining life prediction algorithm where a model of the degradation process is suggested. This preliminary remaining life prediction algorithm serves as a demonstration of how prognostics methodologies could be used for electrolytic capacitors. In addition, the use degradation progression data from accelerated aging, provides an avenue for validation of applications of the Kalman filter based prognostics methods typically used for remaining useful life predictions in other applications.

Towards A Model-Based Prognostics Methodology for Electrolytic Capacitors: A Case Study Based on Electrical Overstress Accelerated Aging

NASA Technical Reports Server (NTRS)

Celaya, Jose R.; Kulkarni, Chetan S.; Biswas, Gautam; Goebel, Kai

2012-01-01

A remaining useful life prediction methodology for electrolytic capacitors is presented. This methodology is based on the Kalman filter framework and an empirical degradation model. Electrolytic capacitors are used in several applications ranging from power supplies on critical avionics equipment to power drivers for electro-mechanical actuators. These devices are known for their comparatively low reliability and given their criticality in electronics subsystems they are a good candidate for component level prognostics and health management. Prognostics provides a way to assess remaining useful life of a capacitor based on its current state of health and its anticipated future usage and operational conditions. We present here also, experimental results of an accelerated aging test under electrical stresses. The data obtained in this test form the basis for a remaining life prediction algorithm where a model of the degradation process is suggested. This preliminary remaining life prediction algorithm serves as a demonstration of how prognostics methodologies could be used for electrolytic capacitors. In addition, the use degradation progression data from accelerated aging, provides an avenue for validation of applications of the Kalman filter based prognostics methods typically used for remaining useful life predictions in other applications.

DNA hydrogel-based supercapacitors operating in physiological fluids

PubMed Central

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

2013-01-01

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

Inorganic proton conducting electrolyte coupled oxide-based dendritic transistors for synaptic electronics.

PubMed

Wan, Chang Jin; Zhu, Li Qiang; Zhou, Ju Mei; Shi, Yi; Wan, Qing

2014-05-07

Ionic/electronic hybrid devices with synaptic functions are considered to be the essential building blocks for neuromorphic systems and brain-inspired computing. Here, artificial synapses based on indium-zinc-oxide (IZO) transistors gated by nanogranular SiO2 proton-conducting electrolyte films are fabricated on glass substrates. Spike-timing dependent plasticity and paired-pulse facilitation are successfully mimicked in an individual bottom-gate transistor. Most importantly, dynamic logic and dendritic integration established by spatiotemporally correlated spikes are also mimicked in dendritic transistors with two in-plane gates as the presynaptic input terminals.

High Energy Density Aqueous Electrochemical Capacitors with a KI-KOH Electrolyte.

PubMed

Wang, Xingfeng; Chandrabose, Raghu S; Chun, Sang-Eun; Zhang, Tianqi; Evanko, Brian; Jian, Zelang; Boettcher, Shannon W; Stucky, Galen D; Ji, Xiulei

2015-09-16

We report a new electrochemical capacitor with an aqueous KI-KOH electrolyte that exhibits a higher specific energy and power than the state-of-the-art nonaqueous electrochemical capacitors. In addition to electrical double layer capacitance, redox reactions in this device contribute to charge storage at both positive and negative electrodes via a catholyte of IOx-/I- couple and a redox couple of H2O/Had, respectively. Here, we, for the first time, report utilizing IOx-/I- redox couple for the positive electrode, which pins the positive electrode potential to be 0.4-0.5 V vs Ag/AgCl. With the positive electrode potential pinned, we can polarize the cell to 1.6 V without breaking down the aqueous electrolyte so that the negative electrode potential could reach -1.1 V vs Ag/AgCl in the basic electrolyte, greatly enhancing energy storage. Both mass spectroscopy and Raman spectrometry confirm the formation of IO3- ions (+5) from I- (-1) after charging. Based on the total mass of electrodes and electrolyte in a practically relevant cell configuration, the device exhibits a maximum specific energy of 7.1 Wh/kg, operates between -20 and 50 °C, provides a maximum specific power of 6222 W/kg, and has a stable cycling life with 93% retention of the peak specific energy after 14,000 cycles.

Methods and energy storage devices utilizing electrolytes having surface-smoothing additives

DOEpatents

Xu, Wu; Zhang, Jiguang; Graff, Gordon L; Chen, Xilin; Ding, Fei

2015-11-12

Electrodeposition and energy storage devices utilizing an electrolyte having a surface-smoothing additive can result in self-healing, instead of self-amplification, of initial protuberant tips that give rise to roughness and/or dendrite formation on the substrate and anode surface. For electrodeposition of a first metal (M1) on a substrate or anode from one or more cations of M1 in an electrolyte solution, the electrolyte solution is characterized by a surface-smoothing additive containing cations of a second metal (M2), wherein cations of M2 have an effective electrochemical reduction potential in the solution lower than that of the cations of M1.

Textile Inspired Lithium-Oxygen Battery Cathode with Decoupled Oxygen and Electrolyte Pathways.

PubMed

Xu, Shaomao; Yao, Yonggang; Guo, Yuanyuan; Zeng, Xiaoqiao; Lacey, Steven D; Song, Huiyu; Chen, Chaoji; Li, Yiju; Dai, Jiaqi; Wang, Yanbin; Chen, Yanan; Liu, Boyang; Fu, Kun; Amine, Khalil; Lu, Jun; Hu, Liangbing

2018-01-01

The lithium-air (Li-O 2 ) battery has been deemed one of the most promising next-generation energy-storage devices due to its ultrahigh energy density. However, in conventional porous carbon-air cathodes, the oxygen gas and electrolyte often compete for transport pathways, which limit battery performance. Here, a novel textile-based air cathode is developed with a triple-phase structure to improve overall battery performance. The hierarchical structure of the conductive textile network leads to decoupled pathways for oxygen gas and electrolyte: oxygen flows through the woven mesh while the electrolyte diffuses along the textile fibers. Due to noncompetitive transport, the textile-based Li-O 2 cathode exhibits a high discharge capacity of 8.6 mAh cm -2 , a low overpotential of 1.15 V, and stable operation exceeding 50 cycles. The textile-based structure can be applied to a range of applications (fuel cells, water splitting, and redox flow batteries) that involve multiple phase reactions. The reported decoupled transport pathway design also spurs potential toward flexible/wearable Li-O 2 batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Conductive bridging random access memory—materials, devices and applications

NASA Astrophysics Data System (ADS)

Kozicki, Michael N.; Barnaby, Hugh J.

2016-11-01

We present a review and primer on the subject of conductive bridging random access memory (CBRAM), a metal ion-based resistive switching technology, in the context of current research and the near-term requirements of the electronics industry in ultra-low energy devices and new computing paradigms. We include extensive discussions of the materials involved, the underlying physics and electrochemistry, the critical roles of ion transport and electrode reactions in conducting filament formation and device switching, and the electrical characteristics of the devices. Two general cation material systems are given—a fast ion chacogenide electrolyte and a lower ion mobility oxide ion conductor, and numerical examples are offered to enhance understanding of the operation of devices based on these. The effect of device conditioning on the activation energy for ion transport and consequent switching speed is discussed, as well as the mechanisms involved in the removal of the conducting bridge. The morphology of the filament and how this could be influenced by the solid electrolyte structure is described, and the electrical characteristics of filaments with atomic-scale constrictions are discussed. Consideration is also given to the thermal and mechanical environments within the devices. Finite element and compact modelling illustrations are given and aspects of CBRAM storage elements in memory circuits and arrays are included. Considerable emphasis is placed on the effects of ionizing radiation on CBRAM since this is important in various high reliability applications, and the potential uses of the devices in reconfigurable logic and neuromorphic systems is also discussed.

Nonaqueous electrolyte for electrical storage devices

DOEpatents

McEwen, Alan B.; Yair, Ein-Eli

1999-01-01

Improved nonaqueous electrolytes for application in electrical storage devices such as electrochemical capacitors or batteries are disclosed. The electrolytes of the invention contain salts consisting of alkyl substituted, cyclic delocalized aromatic cations, and their perfluoro derivatives, and certain polyatomic anions having a van der Waals volume less than or equal to 100 .ANG..sup.3, preferably inorganic perfluoride anions and most preferably PF.sub.6.sup.-, the salts being dissolved in organic liquids, and preferably alkyl carbonate solvents, or liquid sulfur dioxide or combinations thereof, at a concentration of greater than 0.5M and preferably greater than 1.0M. Exemplary electrolytes comprise 1-ethyl-3-methylimidazolium hexafluorophosphate dissolved in a cyclic or acylic alkyl carbonate, or methyl formate, or a combination therof. These improved electrolytes have useful characteristics such as higher conductivity, higher concentration, higher energy storage capabilities, and higher power characteristics compared to prior art electrolytes. Stacked capacitor cells using electrolytes of the invention permit high energy, high voltage storage.

Metallization of bacterial cellulose for electrical and electronic device manufacture

DOEpatents

Evans, Barbara R.; O'Neill, Hugh M.; Jansen, Valerie Malyvanh; Woodward, Jonathan

2006-01-17

The employment of metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The fuel cell includes an electrolyte membrane comprising a membrane support structure comprising bacterial cellulose, an anode disposed on one side of the electrolyte membrane, and a cathode disposed on an opposite side of the electrolyte membrane. At least one of the anode and the cathode comprises an electrode support structure comprising bacterial cellulose, and a catalyst disposed in or on the electrode support structure.

Method for making an electrochemical cell

DOEpatents

Tuller, Harry L.; Kramer, Steve A.; Spears, Marlene A.; Pal, Uday B.

1996-01-01

An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is provided.

Process for making dense thin films

DOEpatents

Jacobson, Craig P.; Visco, Steven J.; DeJonghe, Lutgard C.

2005-07-26

Provided are low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures. The invention provides solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one embodiment the invention provides techniques for firing of device substrate to form densified electrolyte/membrane films 5 to 20 microns thick. In another embodiment, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe, Cu and Ag, or alloys thereof.

Molecular Design of Efficient Organic D-A-π -A Dye Featuring Triphenylamine as Donor Fragment for Application in Dye-Sensitized Solar Cells.

PubMed

Ferdowsi, Parnian; Saygili, Yasemin; Zhang, Weiwei; Edvinson, Tomas; Kavan, Ladislav; Mokhtari, Javad; Zakeeruddin, Shaik M; Grätzel, Michael; Hagfeldt, Anders

2018-01-23

A metal-free organic sensitizer, suitable for the application in dye-sensitized solar cells (DSSCs), has been designed, synthesized and characterized both experimentally and theoretically. The structure of the novel donor-acceptor-π-bridge-acceptor (D-A-π-A) dye incorporates a triphenylamine (TPA) segment and 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid (BTEBA). The triphenylamine unit is widely used as an electron donor for photosensitizers, owing to its nonplanar molecular configuration and excellent electron-donating capability, whereas 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid is used as an electron acceptor unit. The influences of I 3 - /I - , [Co(bpy) 3 ] 3+/2+ and [Cu(tmby) 2 ] 2+/+ (tmby=4,4',6,6'-tetramethyl-2,2'-bipyridine) as redox electrolytes on the DSSC device performance were also investigated. The maximal monochromatic incident photon-to-current conversion efficiency (IPCE) reached 81 % and the solar light to electrical energy conversion efficiency of devices with [Cu(tmby) 2 ] 2+/+ reached 7.15 %. The devices with [Co(bpy) 3 ] 3+/2+ and I 3 - /I - electrolytes gave efficiencies of 5.22 % and 6.14 %, respectively. The lowest device performance with a [Co(bpy) 3 ] 3+/2+ -based electrolyte is attributed to increased charge recombination. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Role of salt concentration in blend polymer for energy storage conversion devices

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

Arya, Anil; Sharma, A. L., E-mail: alsharmaiitkgp@gmail.com; Sadiq, M.

2016-05-06

Solid Polymer Electrolytes (SPE) are materials of considerable interest worldwide, which serves dual purpose of electrolyte and separator between electrode compartments in renewable energy conversion/storage devices such as; high energy density batteries, electrochromic display devices, and supercapacitors. Polymer blend electrolytes are prepared for various concentration of salt (Ö/Li) with the constant ratio (0.5 gm) of each PEO and PAN polymers (blend polymer) using solution casting technique. Solid polymeric ionic conductor as a separator is the ultimate substitute to eliminate the drawback related to liquid and gel polymer ionic conductors. In the present work, solid polymer electrolyte film consisting of PEO,more » PAN and LiPF{sub 6} are examined for various concentration of lithium salt by keeping PEO/PAN blend ratio as a constant with a view to optimize the dominant salt concentration which could give the maximum conductivity at ambient temperature.« less

Electrochemical Approach for Analyzing Electrolyte Transport Properties and Their Effect on Protonic Ceramic Fuel Cell Performance.

PubMed

Danilov, Nikolay; Lyagaeva, Julia; Vdovin, Gennady; Medvedev, Dmitry; Demin, Anatoly; Tsiakaras, Panagiotis

2017-08-16

The design and development of highly conductive materials with wide electrolytic domain boundaries are among the most promising means of enabling solid oxide fuel cells (SOFCs) to demonstrate outstanding performance across low- and intermediate-temperature ranges. While reducing the thickness of the electrolyte is an extensively studied means for diminishing the total resistance of SOFCs, approaches involving an improvement in the transport behavior of the electrolyte membranes have been less-investigated. In the present work, a strategy for analyzing the electrolyte properties and their effect on SOFC output characteristics is proposed. To this purpose, a SOFC based on a recently developed BaCe 0.5 Zr 0.3 Dy 0.2 O 3-δ proton-conducting ceramic material was fabricated and tested. The basis of the strategy consists of the use of traditional SOFC testing techniques combined with the current interruption method and electromotive force measurements with a modified polarization-correction assessment. This allows one to determine simultaneously such important parameters as maximal power density; ohmic and polarization resistances; average ion transport numbers; and total, ionic, and electronic film conductivities and their activation energies. The proposed experimental procedure is expected to expand both fundamental and applied basics that could be further adopted to improve the technology of electrochemical devices based on proton-conducting electrolytes.

A self-healable and highly stretchable supercapacitor based on a dual crosslinked polyelectrolyte

NASA Astrophysics Data System (ADS)

Huang, Yan; Zhong, Ming; Huang, Yang; Zhu, Minshen; Pei, Zengxia; Wang, Zifeng; Xue, Qi; Xie, Xuming; Zhi, Chunyi

2015-12-01

Superior self-healability and stretchability are critical elements for the practical wide-scale adoption of personalized electronics such as portable and wearable energy storage devices. However, the low healing efficiency of self-healable supercapacitors and the small strain of stretchable supercapacitors are fundamentally limited by conventional polyvinyl alcohol-based acidic electrolytes, which are intrinsically neither self-healable nor highly stretchable. Here we report an electrolyte comprising polyacrylic acid dual crosslinked by hydrogen bonding and vinyl hybrid silica nanoparticles, which displays all superior functions and provides a solution to the intrinsic self-healability and high stretchability problems of a supercapacitor. Supercapacitors with this electrolyte are non-autonomic self-healable, retaining the capacitance completely even after 20 cycles of breaking/healing. These supercapacitors are stretched up to 600% strain with enhanced performance using a designed facile electrode fabrication procedure.

Efficient iodine-free dye-sensitized solar cells employing truxene-based organic dyes.

PubMed

Zong, Xueping; Liang, Mao; Chen, Tao; Jia, Jiangnan; Wang, Lina; Sun, Zhe; Xue, Song

2012-07-07

Two new truxene-based organic sensitizers (M15 and M16) featuring high extinction coefficients were synthesized for dye-sensitized solar cells employing cobalt electrolyte. The M16-sensitized device displays a 7.6% efficiency at an irradiation of AM1.5 full sunlight.

Dielectrophoretic trapping of DNA-coated gold nanoparticles on silicon based vertical nanogap devices.

PubMed

Strobel, Sebastian; Sperling, Ralph A; Fenk, Bernhard; Parak, Wolfgang J; Tornow, Marc

2011-06-07

We report on the successful dielectrophoretic trapping and electrical characterization of DNA-coated gold nanoparticles on vertical nanogap devices (VNDs). The nanogap devices with an electrode distance of 13 nm were fabricated from Silicon-on-Insulator (SOI) material using a combination of anisotropic reactive ion etching (RIE), selective wet chemical etching and metal thin-film deposition. Au nanoparticles (diameter 40 nm) coated with a monolayer of dithiolated 8 base pairs double stranded DNA were dielectrophoretically trapped into the nanogap from electrolyte buffer solution at MHz frequencies as verified by scanning and transmission electron microscopy (SEM/TEM) analysis. First electrical transport measurements through the formed DNA-Au-DNA junctions partially revealed an approximately linear current-voltage characteristic with resistance in the range of 2-4 GΩ when measured in solution. Our findings point to the importance of strong covalent bonding to the electrodes in order to observe DNA conductance, both in solution and in the dry state. We propose our setup for novel applications in biosensing, addressing the direct interaction of biomolecular species with DNA in aqueous electrolyte media.

A stable and convenient protein electrophoresis titration device with bubble removing system.

PubMed

Zhang, Qiang; Fan, Liu-Yin; Li, Wen-Lin; Cong, Feng-Song; Zhong, Ran; Chen, Jing-Jing; He, Yu-Chen; Xiao, Hua; Cao, Cheng-Xi

2017-07-01

Moving reaction boundary titration (MRBT) has a potential application to immunoassay and protein content analysis with high selectivity. However, air bubbles often impair the accuracy of MRBT, and the leakage of electrolyte greatly decreases the safety and convenience of electrophoretic titration. Addressing these two issues a reliable MRBT device with modified electrolyte chamber of protein titration was designed. Multiphysics computer simulation was conducted for optimization according to two-phase flow. The single chamber was made of two perpendicular cylinders with different diameters. After placing electrophoretic tube, the resident air in the junction next to the gel could be eliminated by a simple fast electrolyte flow. Removing the electrophoretic tube automatically prevented electrolyte leakage at the junction due to the gravity-induced negative pressure within the chamber. Moreover, the numerical simulation and experiments showed that the improved MRBT device has following advantages: (i) easy and rapid setup of electrophoretic tube within 20 s; (ii) simple and quick bubble dissipates from the chamber of titration within 2 s; (iii) no electrolyte leakage from the two chambers: and (iv) accurate protein titration and safe instrumental operation. The developed technique and apparatus greatly improves the performance of the previous MRBT device, and providing a new route toward practical application. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alkali-Resistant Quasi-Solid-State Electrolyte for Stretchable Supercapacitors.

PubMed

Tang, Qianqiu; Wang, Wenqiang; Wang, Gengchao

2016-10-05

Research on stretchable energy-storage devices has been motivated by elastic electronics, and considerable research efforts have been devoted to the development of stretchable electrodes. However, stretchable electrolytes, another critical component in stretchable devices, have earned quite little attention, especially the alkali-resistant ones. Here, we reported a novel stretchable alkali-resistant electrolyte made of a polyolefin elastomer porous membrane supported potassium hydroxide-potassium polyacrylate (POE@KOH-PAAK). The as-prepared electrolyte shows a negligible plastic deformation even after 1000 stretching cycles at a strain of 150% as well as a high conductivity of 0.14 S cm -1 . It also exhibits excellent alkali resistance, which shows no obvious degradation of the mechanical performance after immersion in 2 M KOH for up to 2 weeks. To demonstrate its good properties, a high-performance stretchable supercapacitor is assembled using a carbon-nanotube-film-supported NiCo 2 O 4 (CNT@NiCo 2 O 4 ) as the cathode and Fe 2 O 3 (CNT@Fe 2 O 3 ) as the anode, proving great application promise of the stretchable alkali-resistant electrolyte in stretchable energy-storage devices.

High ionic conductivity P(VDF-TrFE)/PEO blended polymer electrolytes for solid electrochromic devices.

PubMed

Nguyen, Chien A; Xiong, Shanxin; Ma, Jan; Lu, Xuehong; Lee, Pooi See

2011-08-07

Solid polymer electrolytes with excellent ionic conductivity (above 10(-4) S cm(-1)), which result in high optical modulation for solid electrochromic (EC) devices are presented. The combination of a polar host matrix poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) and a solid plasticized of a low molecular weight poly(ethylene oxide) (PEO) (M(w)≤ 20,000) blended polymer electrolyte serves to enhance both the dissolution of lithium salt and the ionic transport. Calorimetric measurement shows a reduced crystallization due to a better intermixing of the polymers with small molecular weight PEO. Vibrational spectroscopy identifies the presence of free ions and ion pairs in the electrolytes with PEO of M(w)≤ 8000. The ionic dissolution is improved using PEO as a plasticizer when compared to liquid propylene carbonate, evidently shown in the transference number analysis. Ionic transport follows the Arrhenius equation with a low activation energy (0.16-0.2 eV), leading to high ionic conductivities. Solid electrochromic devices fabricated with the blended P(VDF-TrFE)/PEO electrolytes and polyaniline show good spectroelectrochemical performance in the visible (300-800 nm) and near-infrared (0.9-2.4 μm) regions with a modulation up to 60% and fast switching speed of below 20 seconds. The successful introduction of the solid polymer electrolytes with its best harnessed qualities helps to expedite the application of various electrochemical devices. This journal is © the Owner Societies 2011

Gate-Induced Metal–Insulator Transition in MoS 2 by Solid Superionic Conductor LaF 3

DOE PAGES

Wu, Chun-Lan; Yuan, Hongtao; Li, Yanbin; ...

2018-03-23

Electric-double-layer (EDL) gating with liquid electrolyte has been a powerful tool widely used to explore emerging interfacial electronic phenomena. Due to the large EDL capacitance, a high carrier density up to 10 14 cm –2 can be induced, directly leading to the realization of field-induced insulator to metal (or superconductor) transition. However, the liquid nature of the electrolyte has created technical issues including possible side electrochemical reactions or intercalation, and the potential for huge strain at the interface during cooling. In addition, the liquid coverage of active devices also makes many surface characterizations and in situ measurements challenging. Here, wemore » demonstrate an all solid-state EDL device based on a solid superionic conductor LaF 3, which can be used as both a substrate and a fluorine ionic gate dielectric to achieve a wide tunability of carrier density without the issues of strain or electrochemical reactions and can expose the active device surface for external access. Based on LaF 3 EDL transistors (EDLTs), we observe the metal–insulator transition in MoS 2. Interestingly, the well-defined crystal lattice provides a more uniform potential distribution in the substrate, resulting in less interface electron scattering and therefore a higher mobility in MoS 2 transistors. Finally, this result shows the powerful gating capability of LaF 3 solid electrolyte for new possibilities of novel interfacial electronic phenomena.« less

Solid electroytes for CNT-based actuators

NASA Astrophysics Data System (ADS)

Riemenschneider, Johannes; Geier, Sebastian; Mahrholz, Thorsten; Mosch, Jürgen; Monner, Hans Peter; Sinapius, Michael

2009-03-01

Actuators based on carbon nanotubes (CNT) have the potential to generate high forces at very low voltages. The density of the raw material is just 1330 kg/m3, which makes them well applicable for lightweight applications. Moreover, active strains of up to 1% can be achieved - due to the CNTs dimensional changes on charge injection. Therefore the nanotubes have to be arranged and electrically wired like electrodes of a capacitor. In previous works the system's response of the Nanotubes comprising a liquid electrolyte was studied in detail. The major challenge is to repeat such experiments with solid electrolytes, which is a prerequisite for structural integration. In this paper a method is proposed which makes sure the expansion is not based on thermal expansion. This is done by analysing the electrical system response. As thermal expansion is dominated by ohmic resistance the CNT based actuators show a strong capacitive behavior. This behavior is referable to the constitution of the electrochemical double layer around the nanotubes, which causes the tubes to expand. Also a novel test setup is described, which guarantees that the displacement which is measured will not be caused by bending of a bimorph but due to expansion of a single layer of nanotubes. This paper also presents experimental results demonstrating both, the method of electrical characterization of CNT based actuators with implemented solid electrolytes and the novel test setup which is used to measure the needed data. The actuators which were characterized are hybrids of CNT and the solid electrolyte NAFION which is supplying the ions needed to constitute the electrochemical double layer. The manufacturing, processing of these actuators and also some first experimental results are shown. Unfortunately, the results are not as clear as those for liquid electrolytes, which depend on the hybrid character of the analyzed devices. In the liquid electrolyte based case the CNTs are the only source of stiffness, whereas in the solid electrolyte case electrodes and electrolyte contribute to the overall stiffness and damping as well. Since the introduction of solid electrolytes is a major stumbling block in the development of such actuators, this work is of particular importance.

Device for measuring oxygen activity in liquid sodium

DOEpatents

Roy, P.; Young, R.S.

1973-12-01

A composite ceramic electrolyte in a configuration (such as a closed end tube or a plate) suitable to separate liquid sodium from a reference electrode with a high impedance voltmeter connected to measure EMF between the sodium and the reference electrode as a measure of oxygen activity in the sodium is described. The composite electrolyte consists of zirconiacalcia with a bonded layer of thoria-yttria. The device is used with a gaseous reference electrode on the zirconia-calcia side and liquid sodium on the thoria-yttria side of the electrolyte. (Official Gazette)

Electrolyte solutions including a phosphoranimine compound, and energy storage devices including same

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

Klaehn, John R.; Dufek, Eric J.; Rollins, Harry W.

An electrolyte solution comprising at least one phosphoranimine compound and a metal salt. The at least one phosphoranimine compound comprises a compound of the chemical structure ##STR00001## where X is an organosilyl group or a tert-butyl group and each of R.sup.1, R.sup.2, and R.sup.3 is independently selected from the group consisting of an alkyl group, an aryl group, an alkoxy group, or an aryloxy group. An energy storage device including the electrolyte solution is also disclosed.

Research Progress towards Understanding the Unique Interfaces between Concentrated Electrolytes and Electrodes for Energy Storage Applications

PubMed Central

Lochala, Joshua A.; Kwok, Alexander; Deng, Zhiqun Daniel

2017-01-01

The electrolyte is an indispensable component in all electrochemical energy storage and conversion devices with batteries being a prime example. While most research efforts have been pursued on the materials side, the progress for the electrolyte is slow due to the decomposition of salts and solvents at low potentials, not to mention their complicated interactions with the electrode materials. The general properties of bulk electrolytes such as ionic conductivity, viscosity, and stability all affect the cell performance. However, for a specific electrochemical cell in which the cathode, anode, and electrolyte are optimized, it is the interface between the solid electrode and the liquid electrolyte, generally referred to as the solid electrolyte interphase (SEI), that dictates the rate of ion flow in the system. The commonly used electrolyte is within the range of 1–1.2 m based on the prior optimization experience, leaving the high concentration region insufficiently recognized. Recently, electrolytes with increased concentration (>1.0 m) have received intensive attention due to quite a few interesting discoveries in cells containing concentrated electrolytes. The formation mechanism and the nature of the SEI layers derived from concentrated electrolytes could be fundamentally distinct from those of the traditional SEI and thus enable unusual functions that cannot be realized using regular electrolytes. In this article, we provide an overview on the recent progress of high concentration electrolytes in different battery chemistries. The experimentally observed phenomena and their underlying fundamental mechanisms are discussed. New insights and perspectives are proposed to inspire more revolutionary solutions to address the interfacial challenges. PMID:28852621

Research Progress towards Understanding the Unique Interfaces between Concentrated Electrolytes and Electrodes for Energy Storage Applications

DOE PAGES

Zheng, Jianming; Lochala, Joshua A.; Kwok, Alexander; ...

2017-03-31

The electrolyte is an indispensable component in all electrochemical energy storage and conversion devices, for example, batteries. While most research efforts have been pursued on the materials side, the progress for the electrolyte is slow due to the decomposition of salts and solvents at low potentials, not to mention their complicated interactions with the electrode materials. The general properties of bulk electrolytes such as ionic conductivity, viscosity, and stability all affect the cell performance. However, for a specific electrochemical cell in which the cathode, anode and electrolyte are optimized, it is the interface between the solid electrode and the liquidmore » electrolyte, generally referred to as the solid electrolyte interphase (SEI), that dictates the rate of ion flow in the system. The commonly used electrolyte is within the range of 1-1.2 M based on the prior optimization experience, leaving the high concentration region insufficiently recognized. Recently, electrolytes with increased concentration (> 1.0 M) have received additional attention due to quite a few interesting discoveries in cells containing concentrated electrolytes. The formation mechanism and the nature of the SEI layers derived from concentrated electrolytes could be fundamentally different from those of the traditional SEI and thus enable unusual functions that cannot be realized using regular electrolytes. In this article, we provide an overview on the recent progress of high concentration electrolytes in different battery chemistries. The experimentally observed phenomena and their underlying fundamental mechanism are discussed. As a result, new insights and perspectives are proposed to inspire more revolutionary solutions to address the interfacial challenges.« less

Research Progress towards Understanding the Unique Interfaces between Concentrated Electrolytes and Electrodes for Energy Storage Applications.

PubMed

Zheng, Jianming; Lochala, Joshua A; Kwok, Alexander; Deng, Zhiqun Daniel; Xiao, Jie

2017-08-01

The electrolyte is an indispensable component in all electrochemical energy storage and conversion devices with batteries being a prime example. While most research efforts have been pursued on the materials side, the progress for the electrolyte is slow due to the decomposition of salts and solvents at low potentials, not to mention their complicated interactions with the electrode materials. The general properties of bulk electrolytes such as ionic conductivity, viscosity, and stability all affect the cell performance. However, for a specific electrochemical cell in which the cathode, anode, and electrolyte are optimized, it is the interface between the solid electrode and the liquid electrolyte, generally referred to as the solid electrolyte interphase (SEI), that dictates the rate of ion flow in the system. The commonly used electrolyte is within the range of 1-1.2 m based on the prior optimization experience, leaving the high concentration region insufficiently recognized. Recently, electrolytes with increased concentration (>1.0 m) have received intensive attention due to quite a few interesting discoveries in cells containing concentrated electrolytes. The formation mechanism and the nature of the SEI layers derived from concentrated electrolytes could be fundamentally distinct from those of the traditional SEI and thus enable unusual functions that cannot be realized using regular electrolytes. In this article, we provide an overview on the recent progress of high concentration electrolytes in different battery chemistries. The experimentally observed phenomena and their underlying fundamental mechanisms are discussed. New insights and perspectives are proposed to inspire more revolutionary solutions to address the interfacial challenges.

Research Progress towards Understanding the Unique Interfaces between Concentrated Electrolytes and Electrodes for Energy Storage Applications

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

Zheng, Jianming; Lochala, Joshua A.; Kwok, Alexander

The electrolyte is an indispensable component in all electrochemical energy storage and conversion devices, for example, batteries. While most research efforts have been pursued on the materials side, the progress for the electrolyte is slow due to the decomposition of salts and solvents at low potentials, not to mention their complicated interactions with the electrode materials. The general properties of bulk electrolytes such as ionic conductivity, viscosity, and stability all affect the cell performance. However, for a specific electrochemical cell in which the cathode, anode and electrolyte are optimized, it is the interface between the solid electrode and the liquidmore » electrolyte, generally referred to as the solid electrolyte interphase (SEI), that dictates the rate of ion flow in the system. The commonly used electrolyte is within the range of 1-1.2 M based on the prior optimization experience, leaving the high concentration region insufficiently recognized. Recently, electrolytes with increased concentration (> 1.0 M) have received additional attention due to quite a few interesting discoveries in cells containing concentrated electrolytes. The formation mechanism and the nature of the SEI layers derived from concentrated electrolytes could be fundamentally different from those of the traditional SEI and thus enable unusual functions that cannot be realized using regular electrolytes. In this article, we provide an overview on the recent progress of high concentration electrolytes in different battery chemistries. The experimentally observed phenomena and their underlying fundamental mechanism are discussed. As a result, new insights and perspectives are proposed to inspire more revolutionary solutions to address the interfacial challenges.« less

Command Surface of Self-Organizing Structures by Radical Polymers with Cooperative Redox Reactivity.

PubMed

Sato, Kan; Mizuma, Takahiro; Nishide, Hiroyuki; Oyaizu, Kenichi

2017-10-04

Robust radical-substituted polymers with ideal redox capability were used as "command surfaces" for liquid crystal orientation. The alignment of the smectic liquid crystal electrolytes with low-dimensional ion conduction pathways was reversible and readily switched in response to the redox states of the polymers. In one example, a charge storage device with a cooperative redox effect was fabricated. The bulk ionic conductivity of the cell was significantly decreased only after the electrode was fully charged, due to the anisotropic ionic conductivity of the electrolytes (ratio >10 3 ). The switching enabled both a rapid cell response and long charge retention. Such a cooperative command surface of self-assembled structures will give rise to new highly energy efficient supramolecular-based devices including batteries, charge carriers, and actuators.

Cheap, High-Performance, and Wearable Mn Oxide Supercapacitors with Urea-LiClO4 Based Gel Electrolytes.

PubMed

Deng, Ming-Jay; Chen, Kai-Wen; Che, Yo-Cheng; Wang, I-Ju; Lin, Chih-Ming; Chen, Jin-Ming; Lu, Kueih-Tzu; Liao, Yen-Fa; Ishii, Hirofumi

2017-01-11

Here we report a simple, scalable, and low-cost method to enhance the electrochemical properties of Mn oxide electrodes for highly efficient and flexible symmetrical supercapacitors. The method involving printing on a printer, pencil-drawing, and electrodeposition is established to fabricate Mn oxide/Ni-nanotube/graphite/paper hybrid electrodes operating with a low-cost, novel urea-LiClO 4 /PVA as gel electrolyte for flexible solid-state supercapacitor (FSSC) devices. The Mn oxide nanofiber/Ni-nanotube/graphite/paper (MNNGP) electrodes in urea-LiClO 4 /PVA gel electrolyte show specific capacitance (C sp ) 960 F/g in voltage region 0.8 V at 5 mV/s and exhibit excellent rates of capacitance retention more than 85% after 5000 cycles. Moreover, the electrochemical behavior of the MNNGP electrodes in urea-LiClO 4 /PVA at operating temperatures 27-110 °C was investigated; the results show that the MNNGP electrodes in urea-LiClO 4 /PVA exhibit outstanding performance (1100 F/g), even at 90 °C. The assembled FSSC devices based on the MNNGP electrodes in urea-LiClO 4 /PVA exhibit great C sp (380 F/g in potential region of 2.0 V at 5 mV/s, exhibiting superior energy density 211.1 W h/kg) and great cycle stability (less than 15% loss after 5000 cycles at 25 mV/s). The oxidation-state change was examined by in situ X-ray absorption spectroscopy. FSSC devices would open new opportunities in developing novel portable, wearable, and roll-up electric devices owing to the cheap, high-performance, wide range of operating temperature, and simple procedures for large-area fabrication.

Cobalt selenide hollow nanorods array with exceptionally high electrocatalytic activity for high-efficiency quasi-solid-state dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Jin, Zhitong; Zhang, Meirong; Wang, Min; Feng, Chuanqi; Wang, Zhong-Sheng

2018-02-01

In quasi-solid-state dye-sensitized solar cells (QSDSSCs), electron transport through a random network of catalyst in the counter electrode (CE) and electrolyte diffusion therein are limited by the grain boundaries of catalyst particles, thus diminishing the electrocatalytic performance of CE and the corresponding photovoltaic performance of QSDSSCs. We demonstrate herein an ordered Co0.85Se hollow nanorods array film as the Pt-free CE of QSDSSCs. The Co0.85Se hollow nanorods array displays excellent electrocatalytic activity for the reduction of I3- in the quasi-solid-state electrolyte with extremely low charge transfer resistance at the CE/electrolyte interface, and the diffusion of redox species within the Co0.85Se hollow nanorods array CE is pretty fast. The QSDSSC device with the Co0.85Se hollow nanorods array CE produces much higher photovoltaic conversion efficiency (8.35%) than that (4.94%) with the Co0.85Se randomly packed nanorods CE, against the control device with the Pt CE (7.75%). Moreover, the QSDSSC device based on the Co0.85Se hollow nanorods array CE presents good long-term stability with only 4% drop of power conversion efficiency after 1086 h one-sun soaking.

Ionic current devices-Recent progress in the merging of electronic, microfluidic, and biomimetic structures.

PubMed

Koo, Hyung-Jun; Velev, Orlin D

2013-05-09

We review the recent progress in the emerging area of devices and circuits operating on the basis of ionic currents. These devices operate at the intersection of electrochemistry, electronics, and microfluidics, and their potential applications are inspired by essential biological processes such as neural transmission. Ionic current rectification has been demonstrated in diode-like devices containing electrolyte solutions, hydrogel, or hydrated nanofilms. More complex functions have been realized in ionic current based transistors, solar cells, and switching memory devices. Microfluidic channels and networks-an intrinsic component of the ionic devices-could play the role of wires and circuits in conventional electronics.

Towards Prognostics of Electrolytic Capacitors

NASA Technical Reports Server (NTRS)

Celaya, Jose R.; Kulkarni, Chetan; Biswas, Gautam; Goegel, Kai

2011-01-01

A remaining useful life prediction algorithm and degradation model for electrolytic capacitors is presented. Electrolytic capacitors are used in several applications ranging from power supplies on critical avionics equipment to power drivers for electro-mechanical actuators. These devices are known for their low reliability and given their criticality in electronics subsystems they are a good candidate for component level prognostics and health management research. Prognostics provides a way to assess remaining useful life of a capacitor based on its current state of health and its anticipated future usage and operational conditions. In particular, experimental results of an accelerated aging test under electrical stresses are presented. The capacitors used in this test form the basis for a remaining life prediction algorithm where a model of the degradation process is suggested. This preliminary remaining life prediction algorithm serves as a demonstration of how prognostics methodologies could be used for electrolytic capacitors.

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.

Measuring the state of charge of the electrolyte solution in a vanadium redox flow battery using a four-pole cell device

NASA Astrophysics Data System (ADS)

Ngamsai, Kittima; Arpornwichanop, Amornchai

2015-12-01

The decrease in the efficiency and capacity of a vanadium redox flow battery (VRB) caused by an electrolyte imbalance is an important impediment to its long-term operation. Knowing the state of charge (SOC) of an electrolyte solution can quantify the level of the electrolyte imbalance in the VRB. In this study, a four-pole cell device is devised and employed to predict the SOC. The proposed method directly measures the ionic resistance of the electrolyte solution and is sufficiently precise to be applied in real-time mode. Experimental studies on the effects of the operating current on the four-pole cell and the concentrations of vanadium and sulfuric acid in the electrolyte solution are carried out. The results show that the four-pole cell method can be utilized to measure the electrolyte SOC. The concentrations of vanadium and sulfuric acid in the electrolyte solution affect the ionic resistance of the solution. Regarding the capacity and efficiency of the VRB system, the results indicate that the electrical charge is determined from the concentration of vanadium and that the cell voltage depends on the concentration of sulfuric acid in the electrolyte solution. The decreased vanadium concentration and increased sulfuric acid concentration improves the cell voltage efficiency.

Electrocatalytic cermet gas detector/sensor

DOEpatents

Vogt, Michael C.; Shoemarker, Erika L.; Fraioli, deceased, Anthony V.

1995-01-01

An electrocatalytic device for sensing gases. The gas sensing device includes a substrate layer, a reference electrode disposed on the substrate layer comprised of a nonstoichiometric chemical compound enabling oxygen diffusion therethrough, a lower reference electrode coupled to the reference electrode, a solid electrolyte coupled to the lower reference electrode and an upper catalytically active electrode coupled to the solid electrolyte.

A self-healable and highly stretchable supercapacitor based on a dual crosslinked polyelectrolyte

PubMed Central

Huang, Yan; Zhong, Ming; Huang, Yang; Zhu, Minshen; Pei, Zengxia; Wang, Zifeng; Xue, Qi; Xie, Xuming; Zhi, Chunyi

2015-01-01

Superior self-healability and stretchability are critical elements for the practical wide-scale adoption of personalized electronics such as portable and wearable energy storage devices. However, the low healing efficiency of self-healable supercapacitors and the small strain of stretchable supercapacitors are fundamentally limited by conventional polyvinyl alcohol-based acidic electrolytes, which are intrinsically neither self-healable nor highly stretchable. Here we report an electrolyte comprising polyacrylic acid dual crosslinked by hydrogen bonding and vinyl hybrid silica nanoparticles, which displays all superior functions and provides a solution to the intrinsic self-healability and high stretchability problems of a supercapacitor. Supercapacitors with this electrolyte are non-autonomic self-healable, retaining the capacitance completely even after 20 cycles of breaking/healing. These supercapacitors are stretched up to 600% strain with enhanced performance using a designed facile electrode fabrication procedure. PMID:26691661

Non-aqueous electrolytes for lithium ion batteries

DOEpatents

Chen, Zonghai; Amine, Khalil

2015-11-12

The present invention is generally related to electrolytes containing anion receptor additives to enhance the power capability of lithium-ion batteries. The anion receptor of the present invention is a Lewis acid that can help to dissolve LiF in the passivation films of lithium-ion batteries. Accordingly, one aspect the invention provides electrolytes comprising a lithium salt; a polar aprotic solvent; and an anion receptor additive; and wherein the electrolyte solution is substantially non-aqueous. Further there are provided electrochemical devices employing the electrolyte and methods of making the electrolyte.

Computational and experimental characterization of a pyrrolidinium-based ionic liquid for electrolyte applications

NASA Astrophysics Data System (ADS)

Torabifard, Hedieh; Reed, Luke; Berry, Matthew T.; Hein, Jason E.; Menke, Erik; Cisneros, G. Andrés

2017-10-01

The development of Li-ion batteries for energy storage has received significant attention. The synthesis and characterization of electrolytes in these batteries are an important component of this development. Ionic liquids (ILs) have been proposed as possible electrolytes in these devices. Thus, the accurate determination of thermophysical properties for these solvents becomes important for determining their applicability as electrolytes. In this contribution, we present the synthesis and experimental/computational characterization of thermodynamic and transport properties of a pyrrolidinium based ionic liquid as a first step to investigate the possible applicability of this class of ILs for Li-ion batteries. A quantum mechanical-based force field with many-body polarizable interactions has been developed for the simulation of spirocyclic pyrrolidinium, [sPyr+], with BF4- and Li+. Molecular dynamics calculations employing intra-molecular polarization predicted larger heat of vaporization and self-diffusion coefficients and smaller densities in comparison with the model without intra-molecular polarization, indicating that the inclusion of this term can significantly effect the inter-ionic interactions. The calculated properties are in good agreement with available experimental data for similar IL pairs and isothermal titration calorimetry data for [sPyr+][BF4-].

Activated carbon and single-walled carbon nanotube based electrochemical capacitor in 1 M LiPF{sub 6} electrolyte

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

Azam, M.A., E-mail: asyadi@utem.edu.my; Jantan, N.H.; Dorah, N.

2015-09-15

Highlights: • Activated carbon and single-walled CNT based electrochemical capacitor. • Electrochemical analysis by means of CV, charge/discharge and impedance. • 1 M LiPF{sub 6} non-aqueous solution as an electrolyte. • AC/SWCNT electrode exhibits a maximum capacitance of 60.97 F g{sup −1}. - Abstract: Carbon nanotubes have been extensively studied because of their wide range of potential application such as in nanoscale electric circuits, textiles, transportation, health, and the environment. Carbon nanotubes feature extraordinary properties, such as electrical conductivities higher than those of copper, hardness and thermal conductivity higher than those of diamond, and strength surpassing that of steel, amongmore » others. This research focuses on the fabrication of an energy storage device, namely, an electrochemical capacitor, by using carbon materials, i.e., activated carbon and single-walled carbon nanotubes, of a specific weight ratio as electrode materials. The electrolyte functioning as an ion carrier is 1 M lithium hexafluorophosphate. Variations in the electrochemical performance of the device, including its capacitance, charge/discharge characteristics, and impedance, are reported in this paper. The electrode proposed in this work exhibits a maximum capacitance of 60.97 F g{sup −1} at a scan rate of 1 mV s{sup −1}.« less

High-performance dye-sensitized solar cells based on solvent-free electrolytes produced from eutectic melts.

PubMed

Bai, Yu; Cao, Yiming; Zhang, Jing; Wang, Mingkui; Li, Renzhi; Wang, Peng; Zakeeruddin, Shaik M; Grätzel, Michael

2008-08-01

Low-cost excitonic solar cells based on organic optoelectronic materials are receiving an ever-increasing amount of attention as potential alternatives to traditional inorganic photovoltaic devices. In this rapidly developing field, the dye-sensitized solar cell (DSC) has achieved so far the highest validated efficiency of 11.1% (ref. 2) and remarkable stability. However, the cells with the best performance use volatile solvents in their electrolytes, which may be prohibitive for outdoor solar panels in view of the need for robust encapsulation. Solvent-free room-temperature ionic liquids have been pursued as an attractive solution to this dilemma, and device efficiencies of over 7% were achieved by using some low-viscosity formulations containing 1-ethyl-3-methylimidazolium thiocyanate, selenocyanate, tricyanomethide or tetracyanoborate. Unfortunately, apart from tetracyanoborate, all of these low-viscosity melts proved to be unstable under prolonged thermal stress and light soaking. Here, we introduce the concept of using eutectic melts to produce solvent-free liquid redox electrolytes. Using a ternary melt in conjunction with a nanocrystalline titania film and the amphiphilic heteroleptic ruthenium complex Z907Na (ref. 10) as a sensitizer, we reach excellent stability and an unprecedented efficiency of 8.2% under air-mass 1.5 global illumination. Our results are of importance to realize large-scale outdoor applications of mesoscopic DSCs.

Biocompatible ionic liquid-biopolymer electrolyte-enabled thin and compact magnesium-air batteries.

PubMed

Jia, Xiaoteng; Yang, Yang; Wang, Caiyun; Zhao, Chen; Vijayaraghavan, R; MacFarlane, Douglas R; Forsyth, Maria; Wallace, Gordon G

2014-12-10

With the surge of interest in miniaturized implanted medical devices (IMDs), implantable power sources with small dimensions and biocompatibility are in high demand. Implanted battery/supercapacitor devices are commonly packaged within a case that occupies a large volume, making miniaturization difficult. In this study, we demonstrate a polymer electrolyte-enabled biocompatible magnesium-air battery device with a total thickness of approximately 300 μm. It consists of a biocompatible polypyrrole-para(toluene sulfonic acid) cathode and a bioresorbable magnesium alloy anode. The biocompatible electrolyte used is made of choline nitrate (ionic liquid) embedded in a biopolymer, chitosan. This polymer electrolyte is mechanically robust and offers a high ionic conductivity of 8.9 × 10(-3) S cm(-1). The assembled battery delivers a maximum volumetric power density of 3.9 W L(-1), which is sufficient to drive some types of IMDs, such as cardiac pacemakers or biomonitoring systems. This miniaturized, biocompatible magnesium-air battery may pave the way to a future generation of implantable power sources.

Electrochemical energy storage in montmorillonite K10 clay based composite as supercapacitor using ionic liquid electrolyte.

PubMed

Maiti, Sandipan; Pramanik, Atin; Chattopadhyay, Shreyasi; De, Goutam; Mahanty, Sourindra

2016-02-15

Exploring new electrode materials is the key to realize high performance energy storage devices for effective utilization of renewable energy. Natural clays with layered structure and high surface area are prospective materials for electrical double layer capacitors (EDLC). In this work, a novel hybrid composite based on acid-leached montmorillonite (K10), multi-walled carbon nanotube (MWCNT) and manganese dioxide (MnO2) was prepared and its electrochemical properties were investigated by fabricating two-electrode asymmetric supercapacitor cells against activated carbon (AC) using 1.0M tetraethylammonium tetrafluroborate (Et4NBF4) in acetonitrile (AN) as electrolyte. The asymmetric supercapacitors, capable of operating in a wide potential window of 0.0-2.7V, showed a high energy density of 171Whkg(-1) at a power density of ∼1.98kWkg(-1). Such high EDLC performance could possibly be linked to the acid-base interaction of K10 through its surface hydroxyl groups with the tetraethylammonium cation [(C2H5)4N(+) or TEA(+)] of the ionic liquid electrolyte. Even at a very high power density of 96.4kWkg(-1), the cells could still deliver an energy density of 91.1Whkg(-1) exhibiting an outstanding rate capability. The present study demonstrates for the first time, the excellent potential of clay-based composites for high power energy storage device applications. Copyright © 2015 Elsevier Inc. All rights reserved.

Electrocatalytic cermet gas detector/sensor

DOEpatents

Vogt, M.C.; Shoemarker, E.L.; Fraioli, A.V.

1995-07-04

An electrocatalytic device for sensing gases is described. The gas sensing device includes a substrate layer, a reference electrode disposed on the substrate layer comprised of a nonstoichiometric chemical compound enabling oxygen diffusion therethrough, a lower reference electrode coupled to the reference electrode, a solid electrolyte coupled to the lower reference electrode and an upper catalytically active electrode coupled to the solid electrolyte. 41 figs.

Electrolyte materials containing highly dissociated metal ion salts

DOEpatents

Lee, H.S.; Geng, L.; Skotheim, T.A.

1996-07-23

The present invention relates to metal ion salts which can be used in electrolytes for producing electrochemical devices, including both primary and secondary batteries, photoelectrochemical cells and electrochromic displays. The salts have a low energy of dissociation and may be dissolved in a suitable polymer to produce a polymer solid electrolyte or in a polar aprotic liquid solvent to produce a liquid electrolyte. The anion of the salts may be covalently attached to polymer backbones to produce polymer solid electrolytes with exclusive cation conductivity. 2 figs.

Long life lithium batteries with stabilized electrodes

DOEpatents

Amine, Khalil [Downers Grove, IL; Liu, Jun [Naperville, IL; Vissers, Donald R [Naperville, IL; Lu, Wenquan [Darien, IL

2009-03-24

The present invention relates to non-aqueous electrolytes having electrode stabilizing additives, stabilized electrodes, and electrochemical devices containing the same. Thus the present invention provides electrolytes containing an alkali metal salt, a polar aprotic solvent, and an electrode stabilizing additive. In some embodiments the additives include a substituted or unsubstituted cyclic or spirocyclic hydrocarbon containing at least one oxygen atom and at least one alkenyl or alkynyl group. When used in electrochemical devices with, e.g., lithium manganese oxide spinel electrodes or olivine or carbon-coated olivine electrodes, the new electrolytes provide batteries with improved calendar and cycle life.

Self-discharge of electrochemical capacitors based on soluble or grafted quinone.

PubMed

Shul, Galyna; Bélanger, Daniel

2016-07-28

The self-discharge of hybrid electrochemical capacitors based on the redox activity of electrolyte additives or grafted species to the electrode material is investigated simultaneously for the cell and each individual electrode. Electrochemical capacitors using a redox-active electrolyte consisting in hydroquinone added to the electrolyte solution and a redox-active electrode based on anthraquinone-grafted carbon as a negative electrode are investigated. The results are analyzed by using Conway kinetic models and compared to those of a common electrochemical double layer capacitor. The self-discharge investigation is complemented by charge/discharge cycling and it is shown that processes affecting galvanostatic charge/discharge cycling and the self-discharge rate occurring at each electrode of an electrochemical capacitor are different but related to each other. The electrochemical capacitor containing hydroquinone in the electrolyte exhibits a much quicker self-discharge rate than that using a negative electrode based on grafted anthraquinone with a 50% decay of the cell voltage of the fully charged device in 0.6 and 6 h, respectively. The fast self-discharge of the former is due to the diffusion of benzoquinone molecules (formed at the positive electrode during charging) to the negative electrode, where they are reduced, causing a quick depolarization. The grafting of anthraquinone molecules on the carbon material of the negative electrode led to a much slower self-discharge, which nonetheless occurred, by the reaction of the reduced form of the grafted species with electrolyte species.

Ultra-thin solid oxide fuel cells: Materials and devices

NASA Astrophysics Data System (ADS)

Kerman, Kian

Solid oxide fuel cells are electrochemical energy conversion devices utilizing solid electrolytes transporting O2- that typically operate in the 800 -- 1000 °C temperature range due to the large activation barrier for ionic transport. Reducing electrolyte thickness or increasing ionic conductivity can enable lower temperature operation for both stationary and portable applications. This thesis is focused on the fabrication of free standing ultrathin (<100 nm) oxide membranes of prototypical O 2- conducting electrolytes, namely Y2O3-doped ZrO2 and Gd2O3-doped CeO2. Fabrication of such membranes requires an understanding of thin plate mechanics coupled with controllable thin film deposition processes. Integration of free standing membranes into proof-of-concept fuel cell devices necessitates ideal electrode assemblies as well as creative processing schemes to experimentally test devices in a high temperature dual environment chamber. We present a simple elastic model to determine stable buckling configurations for free standing oxide membranes. This guides the experimental methodology for Y 2O3-doped ZrO2 film processing, which enables tunable internal stress in the films. Using these criteria, we fabricate robust Y2O3-doped ZrO2 membranes on Si and composite polymeric substrates by semiconductor and micro-machining processes, respectively. Fuel cell devices integrating these membranes with metallic electrodes are demonstrated to operate in the 300 -- 500 °C range, exhibiting record performance at such temperatures. A model combining physical transport of electronic carriers in an insulating film and electrochemical aspects of transport is developed to determine the limits of performance enhancement expected via electrolyte thickness reduction. Free standing oxide heterostructures, i.e. electrolyte membrane and oxide electrodes, are demonstrated. Lastly, using Y2O3-doped ZrO2 and Gd2O 3-doped CeO2, novel electrolyte fabrication schemes are explored to develop oxide alloys and nanoscale compositionally graded membranes that are thermomechanically robust and provide added interfacial functionality. The work in this thesis advances experimental state-of-the-art with respect to solid oxide fuel cell operation temperature, provides fundamental boundaries expected for ultrathin electrolytes, develops the ability to integrate highly dissimilar material (such as oxide-polymer) heterostructures, and introduces nanoscale compositionally graded electrolyte membranes that can lead to monolithic materials having multiple functionalities.

Self-Assembled Polymeric Ionic Liquid-Functionalized Cellulose Nano-crystals: Constructing 3D Ion-conducting Channels Within Ionic Liquid-based Composite Polymer Electrolytes.

PubMed

Shi, Qing Xuan; Xia, Qing; Xiang, Xiao; Ye, Yun Sheng; Peng, Hai Yan; Xue, Zhi Gang; Xie, Xiao Lin; Mai, Yiu-Wing

2017-09-04

Composite polymeric and ionic liquid (IL) electrolytes are some of the most promising electrolyte systems for safer battery technology. Although much effort has been directed towards enhancing the transport properties of polymer electrolytes (PEs) through nanoscopic modification by incorporating nano-fillers, it is still difficult to construct ideal ion conducting networks. Here, a novel class of three-dimensional self-assembled polymeric ionic liquid (PIL)-functionalized cellulose nano-crystals (CNC) confining ILs in surface-grafted PIL polymer chains, able to form colloidal crystal polymer electrolytes (CCPE), is reported. The high-strength CNC nano-fibers, decorated with PIL polymer chains, can spontaneously form three-dimensional interpenetrating nano-network scaffolds capable of supporting electrolytes with continuously connected ion conducting networks with IL being concentrated in conducting domains. These new CCPE have exceptional ionic conductivities, low activation energies (close to bulk IL electrolyte with dissolved Li salt), high Li + transport numbers, low interface resistances and improved interface compatibilities. Furthermore, the CCPE displays good electrochemical properties and a good battery performance. This approach offers a route to leak-free, non-flammable and high ionic conductivity solid-state PE in energy conversion devices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrolytic cell. [For separating anolyte and catholyte

DOEpatents

Bullock, J.S.; Hale, B.D.

1984-09-14

An apparatus is described for the separation of the anolyte and the catholyte during electrolysis. The electrolyte flows through an electrolytic cell between the oppositely charged electrodes. The cell is equipped with a wedge-shaped device, the tapered end being located between the electrodes on the effluent side of the cell. The wedge diverts the flow of the electrolyte to either side of the wedge, substantially separating the anolyte and the catholyte.

Paper-based transparent flexible thin film supercapacitors.

PubMed

Gao, Kezheng; Shao, Ziqiang; Wu, Xue; Wang, Xi; Zhang, Yunhua; Wang, Wenjun; Wang, Feijun

2013-06-21

Paper-based transparent flexible thin film supercapacitors were fabricated using CNF-[RGO]n hybrid paper as an electrode material and charge collector. Owing to the self-anti-stacking of distorted RGO nanosheets and internal electrolyte nanoscale-reservoirs, the device exhibited good electrochemical performance (about 1.73 mF cm(-2)), and a transmittance of about 56% (at 550 nm).

Kinetic and energetic paradigms for dye-sensitized solar cells: moving from the ideal to the real.

PubMed

O'Regan, Brian C; Durrant, James R

2009-11-17

Dye-sensitized solar cells (DSSCs) are photoelectrochemical solar cells. Their function is based on photoinduced charge separation at a dye-sensitized interface between a nanocrystalline, mesoporous metal oxide electrode and a redox electrolyte. They have been the subject of substantial academic and commercial research over the last 20 years, motivated by their potential as a low-cost solar energy conversion technology. Substantial progress has been made in enhancing the efficiency, stability, and processability of this technology and, in particular, the interplay between these technology drivers. However, despite intense research efforts, our ability to identify predictive materials and structure/device function relationships and, thus, achieve the rational optimization of materials and device design, remains relatively limited. A key challenge in developing such predictive design tools is the chemical complexity of the device. DSSCs comprise distinct materials components, including metal oxide nanoparticles, a molecular sensitizer dye, and a redox electrolyte, all of which exhibit complex interactions with each other. In particular, the electrolyte alone is chemically complex, including not only a redox couple (almost always iodide/iodine) but also a range of additional additives found empirically to enhance device performance. These molecular solutes make up typically 20% of the electrolyte by volume. As with most molecular systems, they exhibit complex interactions with both themselves and the other device components (e.g., the sensitizer dye and the metal oxide). Moreover, these interactions can be modulated by solar irradiation and device operation. As such, understanding the function of these photoelectrochemical solar cells requires careful consideration of the chemical complexity and its impact upon device operation. In this Account, we focus on the process by which electrons injected into the nanocrystalline electrode are collected by the external electrical circuit in real devices under operating conditions. We first of all summarize device function, including the energetics and kinetics of the key processes, using an "idealized" description, which does not fully account for much of the chemical complexity of the system. We then go on to consider recent advances in our understanding of the impact of these complexities upon the efficiency of electron collection. These include "catalysis" of interfacial recombination losses by surface adsorption processes and the influence of device operating conditions upon the recombination rate constant and conduction band energy, both attributed to changes in the chemical composition of the interface. We go on to discuss appropriate methodologies for quantifying the efficiency of electron collection in devices under operation. Finally, we show that, by taking into account these advances in our understanding of the DSSC function, we are able to recreate the current/voltage curves of both efficient and degraded devices without any fitting parameters and, thus, gain significant insight into the determinants of DSSC performance.

Electrolyte measurement device and measurement procedure

DOEpatents

Cooper, Kevin R.; Scribner, Louie L.

2010-01-26

A method and apparatus for measuring the through-thickness resistance or conductance of a thin electrolyte is provided. The method and apparatus includes positioning a first source electrode on a first side of an electrolyte to be tested, positioning a second source electrode on a second side of the electrolyte, positioning a first sense electrode on the second side of the electrolyte, and positioning a second sense electrode on the first side of the electrolyte. current is then passed between the first and second source electrodes and the voltage between the first and second sense electrodes is measured.

Paper-based transparent flexible thin film supercapacitors

NASA Astrophysics Data System (ADS)

Gao, Kezheng; Shao, Ziqiang; Wu, Xue; Wang, Xi; Zhang, Yunhua; Wang, Wenjun; Wang, Feijun

2013-05-01

Paper-based transparent flexible thin film supercapacitors were fabricated using CNF-[RGO]n hybrid paper as an electrode material and charge collector. Owing to the self-anti-stacking of distorted RGO nanosheets and internal electrolyte nanoscale-reservoirs, the device exhibited good electrochemical performance (about 1.73 mF cm-2), and a transmittance of about 56% (at 550 nm).Paper-based transparent flexible thin film supercapacitors were fabricated using CNF-[RGO]n hybrid paper as an electrode material and charge collector. Owing to the self-anti-stacking of distorted RGO nanosheets and internal electrolyte nanoscale-reservoirs, the device exhibited good electrochemical performance (about 1.73 mF cm-2), and a transmittance of about 56% (at 550 nm). Electronic supplementary information (ESI) available: Experimental, TEM image, IR spectra, and XRD spectra of cellulose nanofibers, TEM image, and XRD spectra of RGO, graphite, GO nanosheets, CNF paper, and CNF-[RGO]20 hybrid paper, high-resolution C1s spectra of GO, Raman spectra of GO nanosheets, cross-sectional FESEM image of CNF-[RGO]20 hybrid paper and stress-strain curve of T-SC-20. See DOI: 10.1039/c3nr00674c

Anodic Dissolution of Al Current Collectors in Unconventional Solvents for High Voltage Electrochemical Double-Layer Capacitors.

PubMed

Krummacher, Jakob; Heß, Lars-Henning; Balducci, Andrea

2017-09-04

This study investigated the anodic dissolution of Al current collectors in unconventional electrolytes for high voltage electrochemical double-layer capacitors (EDLCs) containing adiponitrile (ADN), 3-cyanopropionic acid methyl ester (CPAME), 2-methyl-glutaronitrile (2-MGN) as solvent, and tetraethylammonium tetrafluoroborate (Et 4 NBF 4 ) and tetraethylammonium bis(trifluoromethanesulfonyl)imide (Et 4 NTFSI) as conductive salts. To have a comparison with the state-of-the-art electrolytes, the same salts were also used in combination with acetonitrile (ACN). The chemical-physical properties of the electrolytes were investigated. Furthermore, their impact on the anodic dissolution of Al was analyzed in detail as well as the influence of this process on the performance of high voltage EDLCs. The results of this study indicated that in the case of Et 4 NBF 4 -based electrolytes, the use of an alternative solvent is very beneficial for the realization of stable devices. When Et 4 NTFSI is used, the reduced solubility of the complex Al(TFSI) 3 appears to be the key for the realization of advanced electrolytes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A lithium superionic conductor.

PubMed

Kamaya, Noriaki; Homma, Kenji; Yamakawa, Yuichiro; Hirayama, Masaaki; Kanno, Ryoji; Yonemura, Masao; Kamiyama, Takashi; Kato, Yuki; Hama, Shigenori; Kawamoto, Koji; Mitsui, Akio

2011-07-31

Batteries are a key technology in modern society. They are used to power electric and hybrid electric vehicles and to store wind and solar energy in smart grids. Electrochemical devices with high energy and power densities can currently be powered only by batteries with organic liquid electrolytes. However, such batteries require relatively stringent safety precautions, making large-scale systems very complicated and expensive. The application of solid electrolytes is currently limited because they attain practically useful conductivities (10(-2) S cm(-1)) only at 50-80 °C, which is one order of magnitude lower than those of organic liquid electrolytes. Here, we report a lithium superionic conductor, Li(10)GeP(2)S(12) that has a new three-dimensional framework structure. It exhibits an extremely high lithium ionic conductivity of 12 mS cm(-1) at room temperature. This represents the highest conductivity achieved in a solid electrolyte, exceeding even those of liquid organic electrolytes. This new solid-state battery electrolyte has many advantages in terms of device fabrication (facile shaping, patterning and integration), stability (non-volatile), safety (non-explosive) and excellent electrochemical properties (high conductivity and wide potential window).

Thiocyanates as attractive redox-active electrolytes for high-energy and environmentally-friendly electrochemical capacitors.

PubMed

Gorska, Barbara; Bujewska, Paulina; Fic, Krzysztof

2017-03-15

This manuscript reports on the novel insight into the development of high voltage carbon/carbon electrochemical capacitors operating in aqueous solutions of alkali metals and ammonium thiocyanates (KSCN, NaSCN, LiSCN, and NH 4 SCN). The effect of salt concentration, electrode porosity and current collectors on the capacitance value, system stability, and power performance has been investigated. Therefore, thiocyanate-based electrolytes were recognized as cheap and highly conductive electrolytic solutions (up to 401 mS cm -1 for NH 4 SCN at RT) allowing a cell voltage of 1.6 V in a symmetric carbon/carbon system to be achieved. At the same time, they display an attractive redox activity, enhancing the energy of the device with a good performance during cycling.

Nonlinear electrokinetic phenomena in microfluidic devices

NASA Astrophysics Data System (ADS)

Ben, Yuxing

This thesis addresses nonlinear electrokinetic mechanisms for transporting fluid and particles in microfluidic devices for potential applications in biomedical chips, microelectronic cooling and micro-fuel cells. Nonlinear electrokinetics have many advantages, such as low voltage, low power, high velocity, and no significant gas formation in the electrolyte. However, they involve new and complex charging and flow mechanisms that are still not fully understood or explored. Linear electrokinetic fingering that occurs when a fluid with a lower electrolyte concentration advances into one with a higher concentration is first analyzed. Unlike earlier miscible fingering theories, the linear stability analysis is carried out in the self-similar coordinates of the diffusing front. This new spectral theory is developed for small-amplitude gravity and viscous miscible fingering phenomena in general and applied to electrokinetic miscible fingering specifically. Transient electrokinetic fingering is shown to be insignificant in sub-millimeter micro-devices. Nonlinear electroosmotic flow around an ion-exchange spherical granule is studied next. When an electric field is applied across a conducting and ion-selective porous granule in an electrolyte solution, a polarized surface layer with excess counter-ions is created. The flux-induced polarization produces a nonlinear slip velocity to produce micro-vortices around this sphere. This polarization layer is reduced by convection at high velocity. Two velocity scalings at low and high electric fields are derived and favorably compared with experimental results. A mixing device based on this mechanism is shown to produce mixing efficiency 10-100 times higher than molecular diffusion. Finally, AC nonlinear electrokinetic flow on planar electrodes is studied. Two double layer charging mechanisms are responsible for the flow---one due to capacitive charging of ions from the bulk electrolyte and one due to Faradaic reactions at the electrode that consume or produce ions in the double layer. Faradaic charging is analyzed for specific reactions. From the theory, particular electrokinetic flows above the electrodes are selected for micropumps and bioparticle trapping by specifying the electrode geometry and the applied voltage and frequency.

Symmetric supercapacitor: Sulphurized graphene and ionic liquid.

PubMed

Shaikh, Jasmin S; Shaikh, Navajsharif S; Kharade, Rohini; Beknalkar, Sonali A; Patil, Jyoti V; Suryawanshi, Mahesh P; Kanjanaboos, Pongsakorn; Hong, Chang Kook; Kim, Jin Hyeok; Patil, Pramod S

2018-10-01

Symmetric supercapacitor is advanced over simple supercapacitor device due to their stability over a large potential window and high energy density. Graphene is a desired candidate for supercapacitor application since it has a high surface area, good electronic conductivity and high electro chemical stability. There is a pragmatic use of ionic liquid electrolyte for supercapacitor due to its stability over a large potential window, good ionic conductivity and eco-friendly nature. For high performance supercapacitor, the interaction between ionic liquid electrolyte and graphene are crucial for better charge transportation. In respect of this, a three-dimensional (3D) nanoporous honeycomb shaped sulfur embedded graphene (S-graphene) has been synthesized by simple chemical method. Here, the fabrication of high performance symmetric supercapacitor is done by using S-graphene as an electrode and [BMIM-PF 6 ] as an electrolyte. The particular architecture of S-graphene benefited to reduce the ion diffusion resistance, providing the large surface area for charge transportation and efficient charge storage. The S-graphene and ionic liquid-based symmetric supercapacitor device showed the large potential window of 3.2 V with high energy density 124 Wh kg -1 at 0.2 A g -1 constant applied current density. Furthermore, this device shows good cycling performance (stability) with a capacitive retention of 95% over 20,000 cycles at a higher current density of 2 A g -1 . Copyright © 2018 Elsevier Inc. All rights reserved.

Bipolar stacked quasi-all-solid-state lithium secondary batteries with output cell potentials of over 6 V

PubMed Central

Matsuo, Takahiro; Gambe, Yoshiyuki; Sun, Yan; Honma, Itaru

2014-01-01

Designing a lithium ion battery (LIB) with a three-dimensional device structure is crucial for increasing the practical energy storage density by avoiding unnecessary supporting parts of the cell modules. Here, we describe the superior secondary battery performance of the bulk all-solid-state LIB cell and a multilayered stacked bipolar cell with doubled cell potential of 6.5 V, for the first time. The bipolar-type solid LIB cell runs its charge/discharge cycle over 200 times in a range of 0.1–1.0 C with negligible capacity decrease despite their doubled output cell potentials. This extremely high performance of the bipolar cell is a result of the superior battery performance of the single cell; the bulk all-solid-state cell has a charge/discharge cycle capability of over 1500 although metallic lithium and LiFePO4 are employed as anodes and cathodes, respectively. The use of a quasi-solid electrolyte consisting of ionic liquid and Al2O3 nanoparticles is considered to be responsible for the high ionic conductivity and electrochemical stability at the interface between the electrodes and the electrolyte. This paper presents the effective applications of SiO2, Al2O3, and CeO2 nanoparticles and various Li+ conducting ionic liquids for the quasi-solid electrolytes and reports the best ever known cycle performances. Moreover, the results of this study show that the bipolar stacked three-dimensional device structure would be a smart choice for future LIBs with higher cell energy density and output potential. In addition, our report presents the advantages of adopting a three-dimensional cell design based on the solid-state electrolytes, which is of particular interest in energy-device engineering for mobile applications. PMID:25124398

Validating the technological feasibility of yttria-stabilized zirconia-based semiconducting-ionic composite in intermediate-temperature solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Cai, Yixiao; Wang, Baoyuan; Wang, Yi; Xia, Chen; Qiao, Jinli; van Aken, Peter A.; Zhu, Bin; Lund, Peter

2018-04-01

YSZ as the electrolyte of choice has dominated the progressive development of solid oxide fuel cell (SOFC) technologies for many years. To enable SOFCs operating at intermediate temperatures of 600 °C or below, major technical advances were built on a foundation of a thin-film YSZ electrolyte, NiO anode, and perovskite cathode, e.g. La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF). Inspired by functionalities in engineered heterostructure interfaces, the present work uses the components from state-of-the-art SOFCs, i.e, the anode NiO-YSZ and the cathode LSCF-YSZ, or the convergence of all three components, i.e., NiO-YSZ-LSCF, to fabricate semiconductor-ionic membranes (SIMs) and devices. A series of proof-of-concept fuel cell devices are designed by using each of the above SIMs sandwiched between two semiconducting Ni0.8Co0.15Al0.05LiO2-δ (NCAL) layers. We systematically compare these novel designs at 600 °C with two reference fuel cells: a commercial product of anode-supported YSZ electrolyte thin-film cell, and a lab-assembled fuel cell with a conventional configuration of NiO-YSZ (anode)/YSZ (electrolyte)/LSCF-YSZ (cathode). In comparison to the reference cells, the SIM device in a configuration of NCAL/NiO-YSZ-LSCF/NCAL reaches more than 3-fold enhancement of the maximum power output. By using spherical aberration-corrected transmission electron microscopy and spectroscopy approaches, this work offers insight into the mechanisms underlying SIM-associated SOFC performance enhancement.

Optimization of absorption bands of dye-sensitized and perovskite tandem solar cells based on loss-in-potential values.

PubMed

Sobuś, Jan; Ziółek, Marcin

2014-07-21

A numerical study of optimal bandgaps of light absorbers in tandem solar cell configurations is presented with the main focus on dye-sensitized solar cells (DSSCs) and perovskite solar cells (PSCs). The limits in efficiency and the expected improvements of tandem structures are investigated as a function of total loss-in-potential (V(L)), incident photon to current efficiency (IPCE) and fill factor (FF) of individual components. It is shown that the optimal absorption onsets are significantly smaller than those derived for multi-junction devices. For example, for double-cell devices the onsets are at around 660 nm and 930 nm for DSSCs with iodide based electrolytes and at around 720 nm and 1100 nm for both DSSCs with cobalt based electrolytes and PSCs. Such configurations can increase the total sunlight conversion efficiency by about 35% in comparison to single-cell devices of the same VL, IPCE and FF. The relevance of such studies for tandem n-p DSSCs and for a proposed new configuration for PSCs is discussed. In particular, it is shown that maximum total losses of 1.7 V for DSSCs and 1.4 V for tandem PSCs are necessary to give any efficiency improvement with respect to the single bandgap device. This means, for example, a tandem n-p DSSC with TiO2 and NiO porous electrodes will hardly work better than the champion single DSSC. A source code of the program used for calculations is also provided.

A Novel Nanoionics-Based Switch for Microwave Applications

NASA Technical Reports Server (NTRS)

Nessel, James A.; Lee, Richard Q.; Mueller, Carl H.; Kozicki, Michael N.; Ren, Minghan; Morse, Jacki

2008-01-01

This paper reports the development and characterization of a novel switching device for use in microwave systems. The device utilizes a switching mechanism based on nanoionics, in which mobile ions within a solid electrolyte undergo an electrochemical process to form and remove a conductive metallic "bridge" to define the change of state. The nanoionics-based switch has demonstrated an insertion loss of approx.0.5dB, isolation of >30dB, low voltage operation (1V), low power (approx. micro-W) and low energy (approx. nJ) consumption, and excellent linearity up to 6 GHz. The switch requires fewer bias operations (due to non-volatile nature) and has a simple planar geometry allowing for novel device structures and easy integration into microwave power distribution circuits.

Ionic Liquids in Lithium-Ion Batteries.

PubMed

Balducci, Andrea

2017-04-01

Lithium-ion batteries are among the most widespread energy storage devices in our society. In order to introduce these devices in new key applications such as transportation, however, their safety and their operative temperature range need to be significantly improved. These improvements can be obtained only by developing new electrolytes. Ionic liquids are presently considered among the most attractive electrolytes for the development of advanced and safer lithium-ion batteries. In this manuscript, the use of various types of ionic liquids, e.g. aprotic and protic, in lithium-ion batteries is considered. The advantages and the limits associated to the use of these innovative electrolytes are critically analysed.

Purely electronic mechanism of electrolyte gating of indium tin oxide thin films

DOE PAGES

Leng, X.; Bozovic, I.; Bollinger, A. T.

2016-08-10

Epitaxial indium tin oxide films have been grown on both LaAlO 3 and yttria-stabilized zirconia substrates using RF magnetron sputtering. Electrolyte gating causes a large change in the film resistance that occurs immediately after the gate voltage is applied, and shows no hysteresis during the charging/discharging processes. When two devices are patterned next to one another and the first one gated through an electrolyte, the second one shows no changes in conductance, in contrast to what happens in materials (like tungsten oxide) susceptible to ionic electromigration and intercalation. These findings indicate that electrolyte gating in indium tin oxide triggers amore » pure electronic process (electron depletion or accumulation, depending on the polarity of the gate voltage), with no electrochemical reactions involved. Electron accumulation occurs in a very thin layer near the film surface, which becomes highly conductive. These results contribute to our understanding of the electrolyte gating mechanism in complex oxides and may be relevant for applications of electric double layer transistor devices.« less

Self bleaching photoelectrochemical-electrochromic device

DOEpatents

Bechinger, Clemens S.; Gregg, Brian A.

2002-04-09

A photoelectrochemical-electrochromic device comprising a first transparent electrode and a second transparent electrode in parallel, spaced relation to each other. The first transparent electrode is electrically connected to the second transparent electrode. An electrochromic material is applied to the first transparent electrode and a nanoporous semiconductor film having a dye adsorbed therein is applied to the second transparent electrode. An electrolyte layer contacts the electrochromic material and the nanoporous semiconductor film. The electrolyte layer has a redox couple whereby upon application of light, the nanoporous semiconductor layer dye absorbs the light and the redox couple oxidizes producing an electric field across the device modulating the effective light transmittance through the device.

Thin film method of conducting lithium-ions

DOEpatents

Zhang, J.G.; Benson, D.K.; Tracy, C.E.

1998-11-10

The present invention relates to the composition of a solid lithium-ion electrolyte based on the Li{sub 2}O-CeO{sub 2}-SiO{sub 2} system having good transparent characteristics and high ion conductivity suitable for uses in lithium batteries, electrochromic devices and other electrochemical applications. 12 figs.

Thin film method of conducting lithium-ions

DOEpatents

Zhang, Ji-Guang; Benson, David K.; Tracy, C. Edwin

1998-11-10

The present invention relates to the composition of a solid lithium-ion electrolyte based on the Li.sub.2 O--CeO.sub.2 --SiO.sub.2 system having good transparent characteristics and high ion conductivity suitable for uses in lithium batteries, electrochromic devices and other electrochemical applications.

The electrical conductivities of polyimide and polyimide/Li triflate composites: An a.c. impedance study

NASA Astrophysics Data System (ADS)

Aziz, Nor Diyana Abdul; Kamarulzaman, Norlida; Subban, Ri Hanum Yahaya; Hamzah, Ahmad Sazali; Ahmed, Azni Zain; Osman, Zurina; Rusdi, Roshidah; Kamarudin, Norashikin; Mohalid, Norhanim; Romli, Ahmad Zafir; Shaameri, Zurina

2017-09-01

Polymer electrolytes have been an essential area of research for many decades. One of the reasons was the need to find new electrolyte materials suitable for device applications like solid-state batteries, supercapacitors, fuel cells, etc. with enhanced characteristics. For more than 40 years, polyimide has been known as a super-engineering plastic due to its excellent thermal stability (Tg > 250 °C) and mechanical properties. Therefore, in an effort to develop new polymer electrolytes, polyimide as a polymer matrix was chosen. Composite films of the polymer doped with lithium salt, LiCF3SO3 was prepared. These PI based polymer electrolyte films were investigated by the alternating current (a.c.) impedance spectroscopy method in the temperature range from 300 K to 373 K. It was observed that conductivity increased with the increase of temperature and amount of doping salt. Alternatively, the activation energy (Ea) of the composite films decreased with the increase of the doping salt, LiCF3SO3.

Multifunctional structural lithium ion batteries for electrical energy storage applications

NASA Astrophysics Data System (ADS)

Javaid, Atif; Zeshan Ali, Muhammad

2018-05-01

Multifunctional structural batteries based on carbon fiber-reinforced polymer composites are fabricated that can bear mechanical loads and act as electrochemical energy storage devices simultaneously. Structural batteries, containing woven carbon fabric anode; lithium cobalt oxide/graphene nanoplatelets coated aluminum cathode; filter paper separator and cross-linked polymer electrolyte, were fabricated through resin infusion under flexible tooling (RIFT) technique. Compression tests, dynamic mechanical thermal analysis, thermogravimetric analysis and impedance spectroscopy were done on the cross-linked polymer electrolytes while cyclic voltammetry, impedance spectroscopy, dynamic mechanical thermal analysis and in-plane shear tests were conducted on the fabricated structural batteries. A range of solid polymer electrolytes with increasing concentrations of lithium perchlorate salt in crosslinked polymer epoxies were formulated. Increased concentrations of electrolyte salt in cross-linked epoxy increased the ionic conductivity, although the compressive properties were compromised. A structural battery, exhibiting simultaneously a capacity of 0.16 mAh L‑1, an energy density of 0.32 Wh L‑1 and a shear modulus of 0.75 GPa have been reported.

Ultraflexible and tailorable all-solid-state supercapacitors using polyacrylamide-based hydrogel electrolyte with high ionic conductivity.

PubMed

Li, Huili; Lv, Tian; Li, Ning; Yao, Yao; Liu, Kai; Chen, Tao

2017-11-30

Hydrogels with high ionic conductivity consisting of a cross-linked polymer network swollen in water are very promising to be used as an electrolyte for all-solid-state supercapacitors. However, there are rather few flexible supercapacitors using ionic conducting hydrogel electrolytes reported to date. In this work, highly flexible and ionic conducting polyacrylamide hydrogels were synthesized through a simple approach. On using the ionic hydrogels as the electrolyte, the resulting supercapacitors not only exhibited a high specific capacitance but also showed a long self-discharge time (over 10 hours to the half of original open-circuit voltage) and a low leakage current. These newly-developed all-solid-state supercapacitors can be bent, knot, and kneaded for 5000 cycles without performance decay, suggesting excellent flexibility and mechanical stability. These all-solid-state supercapacitors can also be easily tailored into strip-like supercapacitors without a short circuit, which provides an efficient approach to fabricate wearable energy storage devices.

Electrolytes as Cathode Interlayers in Inverted Organic Solar Cells: Influence of the Cations on Bias-Dependent Performance.

PubMed

Li, Yaru; Liu, Xiaohui; Li, Xiaodong; Zhang, Wenjun; Xing, Feifei; Fang, Junfeng

2017-03-08

The performance of organic solar cells (OSCs) with edetate electrolytes depends on external bias, and ions are speculated to be responsible for this phenomenon. To clarify the detailed relationship between the ions of electrolytes and the bias-dependent behaviors of devices, this work introduces four edetate cathode interlayers (EDTA-X, X = nH(4-n)Na, n = 0, 1, 2, and 4) containing different kinds and number of cations into inverted OSCs. The results show that the devices initial and saturated (after external bias treatment) power conversion efficiencies (PCEs) both decrease with the increase in the number of H + . Moreover, the bias-dependent degrees increase with the increase in H + number; with that, the PCE increment of EDTA-4H device is 53.4%, while that of the EDTA-4Na device is almost unchanged. The electrical impedance spectroscopy and capacitance-voltage tests reveal that the interfacial recombination is greatly suppressed by external bias treatment, which is not a result of the decreased density of defect states. The results indicate that the ion's motion, specifically the H + motion, under external electrical field is responsible for the bias-dependent behavior, which is conducive to the design of new efficient electrolytic interlayers without bias-dependent performance.

Gas Evolution in Activated-Carbon-Based Supercapacitors with Protic Deep Eutectic Solvent as Electrolyte.

PubMed

Phadke, Satyajit; Amara, Samia; Anouti, Mérièm

2017-09-06

One of the primary causes of aging in supercapacitors are the irreversible faradaic reactions occurring near the operating-voltage limit that lead to the production of gases resulting in device swelling, increased resistance, and lowering of the capacitance. In this study, a protic deep eutectic solvent (DES) consisting of mixture of lithium bis(fluorosulfonyl)imide (LiFSI) with formamide (FMD) as H-bond donor (x LiFSI =0.25; C=2.5 m LiFSI) is investigated as electrolyte for activated carbon (AC)-based electrical double layer capacitors (EDLCs). Characterization of the viscosity, conductivity, and the ionicity of the electrolyte in a wide range of temperatures indicates >88 % salt dissociation. In situ pressure measurements are performed to understand the effect of cycling conditions on the rate of gas generation, quantified by the in operando pressure variation dP/dt. These measurements demonstrate that about 25 % of the faradaic reactions leading to gas generation are electrochemically reversible. Cell aging studies demonstrate promising potential of the LiFSI/FMD as a protic electrolyte for AC-based EDLCs and high energy density close to 30 Wh kg -1 at 2.4 V. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Employing overlayers to improve the performance of Cu 2BaSnS 4 thin film based photoelectrochemical water reduction devices

DOE PAGES

Ge, Jie; Roland, Paul J.; Koirala, Prakash; ...

2017-01-19

Earth-abundant copper-barium-thiostannate Cu 2BaSnS 4 (CBTS)-based thin films have recently been reported to exhibit the optoelectronic and defect properties suitable as absorbers for photoelectrochemical (PEC) water splitting and the top cell of tandem photovoltaic solar cells. However, the photocurrents of CBTS-based PEC devices are still much lower than the theoretical value, partially due to ineffective charge collection at CBTS/water interface and instability of CBTS in electrolytes. Here, we report on overcoming these issues by employing overlayer engineering. We find that CdS/ZnO/TiO 2 overlayers can significant-ly improve the PEC performance, achieving saturated cathodic photocurrents up to 7.8 mA cm -2 atmore » the potential of -0.10 V versus reversible hydrogen electrode (RHE) in a neutral electrolyte solution, which is much higher than the best bare CBTS film attaining a photocurrent of 4.8 mA cm -2 at the potential of -0.2 V versus RHE. Finally, our results suggest a viable approach for improving the performance of CBTS-based PEC cells.« less

Single particle electrochemical sensors and methods of utilization

DOEpatents

Schoeniger, Joseph [Oakland, CA; Flounders, Albert W [Berkeley, CA; Hughes, Robert C [Albuquerque, NM; Ricco, Antonio J [Los Gatos, CA; Wally, Karl [Lafayette, CA; Kravitz, Stanley H [Placitas, NM; Janek, Richard P [Oakland, CA

2006-04-04

The present invention discloses an electrochemical device for detecting single particles, and methods for using such a device to achieve high sensitivity for detecting particles such as bacteria, viruses, aggregates, immuno-complexes, molecules, or ionic species. The device provides for affinity-based electrochemical detection of particles with single-particle sensitivity. The disclosed device and methods are based on microelectrodes with surface-attached, affinity ligands (e.g., antibodies, combinatorial peptides, glycolipids) that bind selectively to some target particle species. The electrodes electrolyze chemical species present in the particle-containing solution, and particle interaction with a sensor element modulates its electrolytic activity. The devices may be used individually, employed as sensors, used in arrays for a single specific type of particle or for a range of particle types, or configured into arrays of sensors having both these attributes.

Stretchable spiral thin-film battery capable of out-of-plane deformation

NASA Astrophysics Data System (ADS)

Kammoun, Mejdi; Berg, Sean; Ardebili, Haleh

2016-11-01

There is a compelling need for innovative design concepts in energy storage devices such as flexible and stretchable batteries that can simultaneously provide electrochemical and mechanical functions to accommodate nonconventional applications including wearable and implantable devices. In this study, we report on the design and fabrication of a stretchable spiral thin-film lithium ion battery that is capable of large out-of-plane deformation of 1300% while exhibiting simultaneous electrochemical functionality. The spiral battery is fabricated using a flexible solid polymer nanocomposite electrolyte film that offers enhanced safety and stability compared to the conventional organic liquid-based electrolyte. The spiral lithium ion battery exhibits robust mechanical stretchability over 9000 stretching cycles and an energy density of 4.862 mWh/cm3 at ∼650% out-of-plane deformation. Finite element analysis of the spiral battery offers insights about the nature of stresses and strains during battery stretching.

Spontaneous Ionic Polarization in Ammonia-Based Ionic Liquid [Spontaneous Ionic Polarization in Ionic Liquid

DOE PAGES

Kim, Ki-jeong; Yuan, Hongtao; Jang, Hoyoung; ...

2018-05-24

Ionic liquids and gels have attracted attention for a variety of energy storage applications, as well as for high performance electrolytes for batteries and super-capacitors. Although the electronic structure of ionic electrolytes in these applications is of practical importance for device design and improved performance, the understanding of the electronic structure of ionic liquids and gels is still at an early stage. Here we report soft x-ray spectroscopic measurements of the surface electronic structure of a representative ammonia-based ionic gel (DEME-TFSI with PSPMMA- PS copolymer). We observe that near the outermost surface, the area of the anion peak (1s Nmore » - core level in TFSI) is relatively larger than that of the cation peak (N + in DEME). This spontaneous ionic polarization of the electrolyte surface, which is absent for the pure ionic liquid without copolymer, can be directly tuned by the copolymer content in the ionic gel, and further results in a modulation in work function. Finally, these results shed new light on the control of surface electronic properties of ionic electrolytes, as well as a difference between their implementation in ionic liquids and gels.« less

Spontaneous Ionic Polarization in Ammonia-Based Ionic Liquid [Spontaneous Ionic Polarization in Ionic Liquid

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

Kim, Ki-jeong; Yuan, Hongtao; Jang, Hoyoung

Ionic liquids and gels have attracted attention for a variety of energy storage applications, as well as for high performance electrolytes for batteries and super-capacitors. Although the electronic structure of ionic electrolytes in these applications is of practical importance for device design and improved performance, the understanding of the electronic structure of ionic liquids and gels is still at an early stage. Here we report soft x-ray spectroscopic measurements of the surface electronic structure of a representative ammonia-based ionic gel (DEME-TFSI with PSPMMA- PS copolymer). We observe that near the outermost surface, the area of the anion peak (1s Nmore » - core level in TFSI) is relatively larger than that of the cation peak (N + in DEME). This spontaneous ionic polarization of the electrolyte surface, which is absent for the pure ionic liquid without copolymer, can be directly tuned by the copolymer content in the ionic gel, and further results in a modulation in work function. Finally, these results shed new light on the control of surface electronic properties of ionic electrolytes, as well as a difference between their implementation in ionic liquids and gels.« less

RF Magnetron Sputtering Deposited W/Ti Thin Film For Smart Window Applications

NASA Astrophysics Data System (ADS)

Oksuz, Lutfi; Kiristi, Melek; Bozduman, Ferhat; Uygun Oksuz, Aysegul

2014-10-01

Electrochromic (EC) devices can change reversible and persistent their optical properties in the visible region (400-800 nm) upon charge insertion/extraction according to the applied voltage. A complementary type EC is a device containing two electrochromic layers, one of which is anodically colored such as vanadium oxide (V2 O5) while the other cathodically colored such as tungsten oxide (WO3) which is separated by an ionic conduction layer (electrolyte). The use of a solid electrolyte such as Nafion eliminates the need for containment of the liquid electrolyte, which simplifies the cell design, as well as improves safety and durability. In this work, the EC device was fabricated on a ITO/glass slide. The WO3-TiO2 thin film was deposited by reactive RF magnetron sputtering using a 2-in W/Ti (9:1%wt) target with purity of 99.9% in a mixture gas of argon and oxygen. As a counter electrode layer, V2O5 film was deposited on an ITO/glass substrate using V2O3 target with the same conditions of reactive RF magnetron sputtering. Modified Nafion was used as an electrolyte to complete EC device. The transmittance spectra of the complementary EC device was measured by optical spectrophotometry when a voltage of +/-3 V was applied to the EC device by computer controlled system. The surface morphology of the films was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) (Fig. 2). The cyclic voltammetry (CV) for EC device was performed by sweeping the potential between +/-3 V at a scan rate of 50 mV/s.

Inhibiting Polysulfide Shuttle in Lithium-Sulfur Batteries through Low-Ion-Pairing Salts and a Triflamide Solvent.

PubMed

Shyamsunder, Abhinandan; Beichel, Witali; Klose, Petra; Pang, Quan; Scherer, Harald; Hoffmann, Anke; Murphy, Graham K; Krossing, Ingo; Nazar, Linda F

2017-05-22

The step-change in gravimetric energy density needed for electrochemical energy storage devices to power unmanned autonomous vehicles, electric vehicles, and enable low-cost clean grid storage is unlikely to be provided by conventional lithium ion batteries. Lithium-sulfur batteries comprising lightweight elements provide a promising alternative, but the associated polysulfide shuttle in typical ether-based electrolytes generates loss in capacity and low coulombic efficiency. The first new electrolyte based on a unique combination of a relatively hydrophobic sulfonamide solvent and a low ion-pairing salt, which inhibits the polysulfide shuttle, is presented. This system behaves as a sparingly solvating electrolyte at slightly elevated temperatures, where it sustains reversible capacities as high as 1200-1500 mAh g -1 over a wide range of current density (2C-C/5, respectively) when paired with a lithium metal anode, with a coulombic efficiency of >99.7 % in the absence of LiNO 3 additive. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid State Ionic Materials - Proceedings of the 4th Asian Conference on Solid State Ionics

NASA Astrophysics Data System (ADS)

Chowdari, B. V. R.; Yahaya, M.; Talib, I. A.; Salleh, M. M.

1994-07-01

The Table of Contents for the full book PDF is as follows: * Preface * I. INVITED PAPERS * Diffusion of Cations and Anions in Solid Electrolytes * Silver Ion Conductors in the Crystalline State * NMR Studies of Superionic Conductors * Hall Effect and Thermoelectric Power in High Tc Hg-Ba-Ca-Cu-O Ceramics * Solid Electrolyte Materials Prepared by Sol-Gel Chemistry * Preparation of Proton-Conducting Gel Films and their Application to Electrochromic Devices * Thin Film Fuel Cells * Zirconia based Solid Oxide Ion Conductors in Solid Oxide Fuel Cells * The Influence of Anion Substitution on Some Phosphate-based Ion Conducting Glasses * Lithium Intercalation in Carbon Electrodes and its Relevance in Rocking Chair Batteries * Chemical Sensors using Proton Conducting Ceramics * NMR/NQR Studies of Y-Ba-Cu-O Superconductors * Silver Molybdate Glasses and Battery Systems * New Highly Conducting Polymer Ionics and their Application in Electrochemical Devices * Study of Li Electrokinetics on Oligomeric Electrolytes using Microelectrodes * Calculation of Conductivity for Mixed-Phase Electrolytes PEO-MX-Immiscible Additive by Means of Effective Medium Theory * II. CONTRIBUTED PAPERS * Phase Relationship and Electrical Conductivity of Sr-V-O System with Vanadium Suboxide * Amorphous Li+ Ionic Conductors in Li2SO4-Li2O-P2O5 System * Fast Ion Transport in KCl-Al2O3 Composites * The Effect of the Second Phase Precipitation on the Ionic Conductivity of Zr0.85Mg0.15O1.85 * Conductivity Measurements and Phase Relationships in CaCl2-CaHCl Solid Electrolyte * Relationships Between Crystal Structure and Sodium Ion Conductivity in Na7Fe4(AsO4)6 and Na3Al2(AsO4)3 * Electrical Conductivity and Solubility Limit of Ti4+ Ion in Na1+x TiyZr2-ySixP3-xO12 System * Study on Sodium Fast Ion Conductors of Na1+3xAlxTi2-xSi2xP3-2xO12 System * Influences of Zirconia on the Properties of β''-Alumina Ceramics * Decay of Luminescence from Cr3+ Ions in β-Alumina * Lithium Ion Conductivity in the Li4XO4-Li2SO4 (X=Si, Ge, Ti) Systems * A DSC and Conductivity Study of the Influence of Cesium Ion on the Beta-Alpha Transition in Silver Iodide * Phase Diagrams, Stoichiometries and Properties of Bi4V2O11:M2+ Solid Electrolytes * Physical Properties of Electrodeposited Silver Chromotungstate * Pseudopotential Study of Bonding in the Superionic Material AgI: The Effect of Statistical Distribution of Mobile Ions * Cubic Phase Dominant Region in Submicron BaTiO3 Particles * The Crystallization of CoZr Amorphous Alloys via Electrical Resistivity * Cation Ratio Related Properties of Synthetic Mg/Al Layered Double Hydroxide and it's Nanocomposite * DC Conductivity of Nano-Particles of Silver Iodide * Effect of Anomalous Diffusion on Quasielastic Scattering in Superionic Conductors * Computer Simulation Study of Conductivity Enhancement in Superionic-Insulator Composites * Dynamics of Superionic Silver and Copper Iodide Salt Melts * Influence of Dopant Salt AgI, Glass Modifier Ag2O and Glass Formers (SeO3 + MoO3) on Electrical Conductivity in Quaternary Glassy System * Fast Ion Conductivity in the Presence of Competitive Network Formers * Role of Alkali Ions in Borate Glasses * Inelastic Light Scattering in Cadmium Borate Glasses * Investigation on Transport Properties of Mixed Glass System 0.75 [0.75AgI:0.25AgCl]. 0.25[Ag2O:CrO3] * Conduction Mechanism in Lithium Tellurite Glasses * Optimized Silver Tungstoarsenate Glass Electrolyte * Stabilized Superfine Zirconia Powder Prepared by Sol-Gel Process * Study of New PAN-based Electrolytes * Electrical and Thermal Characterization of PVA based Polymer Electrolytes * Conductive Electroactive Polymers: Versatile Solid State Ionic Materials * The Role of Ag2O Addition on the Superconducting Properties of Y-124 Compound * Absorption Spectra Studies of the C60 Films on Transition Metal Film Substrates * Effect of Alumina Dispersal on the Conductivity and Crystallite Size of Polymer Electrolyte * New Mixed Galss-Polymer Solid Electrolytes * The Sputtered La0.5Sr0.5MnO3-Yttria Stabilized Zirconia Composite Electrode in Solid Oxide Fuel Cells * A Solid Electrochemical Ferro Sensor for Molten Matte * SnO2-based Sensor for H2S Monitoring-Electrical Conductivity Measurements and Device Testing * Humidity Sensor using Potassium Tungsten Bronze Synthesized from Peroxo-Polytungstic Acid * Study on Li/LiClO4/V6O13 Test Cells * Fabrication and Characterisation of Some Solid Electrolyte Cells Containing CuI and Silver Oxysalts * Solid State Battery of Proton Conducting Sodium Thiosulphate Pentahydrate * Low Temperature Synthesis of LiMn2O4 for Secondary Lithium Batteries * Effect of Different Cathode Active Materials on Battery Performance with Silver Molybdate Electrolyte Partially Substituted with Zinc Oxide * Fabrication and Characterization of Electrochemical Cells based on Silver Molybdoarsenate and Silver Tungstoarsenate Glass Electrolytes * Lorentz Force Dependence of Dissipation in a Granular Superconductor * Late Entry (Invited paper) * Simultaneous Voltammetry and Spectroscopy of Polyaniline in Propylene Carbonate * Author Index * Tentative List of Participants

Physics and applications of electrochromic devices

NASA Astrophysics Data System (ADS)

Pawlicka, Agnieszka; Avellaneda, Cesar O.

2003-07-01

Solid state electrochromic devices (ECD) are of considerable technological and commercial interest because of their controllable transmission, absorption and/or reflectance. For instance, a major application of these devices is in smart windows that can regulate the solar gains of buildings and also in glare attenuation in automobile rear view mirrors. Other applications include solar cells, small and large area flat panel displays, satellite temperature control, food monitoring, and document authentication. A typical electrochromic device has a five-layer structure: GS/TC/EC/IC/IS/TC/GS, where GS is a glass substrate, TC is a transparent conductor, generally ITO (indium tin oxide) or FTO (fluorine tin oxide), EC is an electrochromic coating, IC is an ion conductor (solid or liquid electrolyte) and IS is an ion storage coating. Generally, the EC and IS layers are deposited separately on the TC coatings and then jointed with the IC and sealed. The EC and IS are thin films that can be deposited by sputtering, CVD, sol-gel precursors, etc. There are different kinds of organic, inorganic and organic-inorganic films that can be used to make electrochromic devices. Thin electrochromic films can be: WO3, Nb2O5, Nb2O5:Li+ or Nb2O5-TiO2 coatings, ions storage films: CeO2-TiO2, CeO2-ZrO2 or CeO2-TiO2-ZrO2 and electrolytes like Organically Modified Electrolytes (Ormolytes) or polymeric films also based on natural polymers like starch or cellulose. These last are very interesting due to their high ionic conductivity, high transparency and good mechanical properties. This paper describes construction and properties of different thin oxide and polymeric films and also shows the optical response of an all sol-gel electrochromic device with WO3/Ormolyte/CeO2-TiO2 configuration.

“Rocking-Chair”-Type Metal Hybrid Supercapacitors

DOE PAGES

Yoo, Hyun Deog; Han, Sang-Don; Bayliss, Ryan D.; ...

2016-10-24

Hybrid supercapacitors that follow a “rocking-chair”-type mechanism were developed by coupling divalent metal and activated carbon electrodes in nonaqueous electrolytes. Conventional supercapacitors require a large amount of electrolyte to provide a sufficient quantity of ions to the electrodes, due to their Daniell-type mechanism that depletes the ions from the electrolyte while charging. The alternative “rocking-chair”-type mechanism effectively enhances the energy density of supercapacitors by minimizing the necessary amount of electrolyte, because the ion is replenished from the metal anode while it is adsorbed to the cathode. Newly developed nonaqueous electrolytes for Mg and Zn electrochemistry, based on bis(trifluoromethylsulfonyl)imide (TFSI) salts,more » made the metal hybrid supercapacitors possible by enabling reversible deposition on the metal anodes and reversible adsorption on an activated carbon cathode. Factoring in gains through the cell design, the energy density of the metal hybrid supercapacitors is projected to be a factor of 7 higher than conventional devices thanks to both the “rocking-chair”-type mechanism that minimizes total electrolyte volume and the use of metal anodes, which have substantial merits in capacity and voltage. Self-discharge was also substantially alleviated compared to conventional supercapacitors. This concept offers a route to build supercapacitors that meet dual criteria of power and energy densities with a simple cell design.« less

"Rocking-Chair"-Type Metal Hybrid Supercapacitors.

PubMed

Yoo, Hyun Deog; Han, Sang-Don; Bayliss, Ryan D; Gewirth, Andrew A; Genorio, Bostjan; Rajput, Nav Nidhi; Persson, Kristin A; Burrell, Anthony K; Cabana, Jordi

2016-11-16

Hybrid supercapacitors that follow a "rocking-chair"-type mechanism were developed by coupling divalent metal and activated carbon electrodes in nonaqueous electrolytes. Conventional supercapacitors require a large amount of electrolyte to provide a sufficient quantity of ions to the electrodes, due to their Daniell-type mechanism that depletes the ions from the electrolyte while charging. The alternative "rocking-chair"-type mechanism effectively enhances the energy density of supercapacitors by minimizing the necessary amount of electrolyte, because the ion is replenished from the metal anode while it is adsorbed to the cathode. Newly developed nonaqueous electrolytes for Mg and Zn electrochemistry, based on bis(trifluoromethylsulfonyl)imide (TFSI) salts, made the metal hybrid supercapacitors possible by enabling reversible deposition on the metal anodes and reversible adsorption on an activated carbon cathode. Factoring in gains through the cell design, the energy density of the metal hybrid supercapacitors is projected to be a factor of 7 higher than conventional devices thanks to both the "rocking-chair"-type mechanism that minimizes total electrolyte volume and the use of metal anodes, which have substantial merits in capacity and voltage. Self-discharge was also substantially alleviated compared to conventional supercapacitors. This concept offers a route to build supercapacitors that meet dual criteria of power and energy densities with a simple cell design.

Glassy materials for lithium batteries: electrochemical properties and devices performances

NASA Astrophysics Data System (ADS)

Duclot, Michel; Souquet, Jean-Louis

Amorphous or glassy materials may be used as electrolyte or electrode materials for lithium primary or secondary batteries. A first generation proceeded from classical coin cells in which the organic electrolyte was replaced by a high lithium conductive glassy electrolyte. The solid components were assembled under isostatic pressure. The main advantages of such cells are a good storage stability and ability to operate until 200°C. Nevertheless, the high resistivity of the glassy electrolyte below room temperature and a limited depth for charge and discharge cycles makes these cells not competitive compared to conventional lithium-ion batteries. More promising, are the thin films solid state microbatteries realised by successive depositions of electrodes and electrolyte. The low resistance of the electrolyte amorphous layer allows cycling at temperatures as low as -10°C. The total thickness of thin film batteries, including packaging is less than 100 μm. A capacity of about 100 μAh cm -2 with over 10 4 charge-discharge cycles at 90% in depth of discharge is well suited for energy independent smart cards or intelligent labels, which represent for these devices a large and unrivalled market.

Noncovalent Pi-Pi Stacking at the Carbon-Electrolyte Interface: Controlling the Voltage Window of Electrochemical Supercapacitors.

PubMed

Li, Mengya; Westover, Andrew S; Carter, Rachel; Oakes, Landon; Muralidharan, Nitin; Boire, Timothy C; Sung, Hak-Joon; Pint, Cary L

2016-08-03

A key parameter in the operation of an electrochemical double-layer capacitor is the voltage window, which dictates the device energy density and power density. Here we demonstrate experimental evidence that π-π stacking at a carbon-ionic liquid interface can modify the operation voltage of a supercapacitor device by up to 30%, and this can be recovered by steric hindrance at the electrode-electrolyte interface introduced by poly(ethylene oxide) polymer electrolyte additives. This observation is supported by Raman spectroscopy, electrochemical impedance spectroscopy, and differential scanning calorimetry that each independently elucidates the signature of π-π stacking between imidazole groups in the ionic liquid and the carbon surface and the role this plays to lower the energy barrier for charge transfer at the electrode-electrolyte interface. This effect is further observed universally across two separate ionic liquid electrolyte systems and is validated by control experiments showing an invariant electrochemical window in the absence of a carbon-ionic liquid electrode-electrolyte interface. As interfacial or noncovalent interactions are usually neglected in the mechanistic picture of double-layer capacitors, this work highlights the importance of understanding chemical properties at supercapacitor interfaces to engineer voltage and energy capability.

Investigation of bio polymer electrolyte based on cellulose acetate-ammonium nitrate for potential use in electrochemical devices.

PubMed

Monisha, S; Mathavan, T; Selvasekarapandian, S; Milton Franklin Benial, A; Aristatil, G; Mani, N; Premalatha, M; Vinoth Pandi, D

2017-02-10

Proton conducting materials create prime interest in electro chemical device development. Present work has been carried out to design environment friendly new biopolymer electrolytes (BPEs) using cellulose acetate (CA) complex with different concentrations of ammonium nitrate (NH 4 NO 3 ), which have been prepared as film and characterized. The 50mol% CA and 50mol% NH 4 NO 3 complex has highest ionic conductivity (1.02×10 -3 Scm -1 ). Differential scanning calorimetry shows the changes in glass transition temperature depends on salt concentration. Structural analysis indicates that the highest ionic conductivity complex exhibits more amorphous nature. Vibrational analysis confirms the complex formation, which has been validated theoretically by Gaussian 09 software. Conducting element in the BPEs has been predicted. Primary proton battery and proton exchange membrane fuel cell have been developed for highest ionic conductivity complex. Output voltage and power performance has been compared for single fuel cell application, which manifests the present BPE holds promise application in electrochemical devices. Copyright © 2016 Elsevier Ltd. All rights reserved.

Porous membrane electrochemical cell for uranium and transuranic recovery from molten salt electrolyte

DOEpatents

Willit, James L [Ratavia, IL

2007-09-11

An improved process and device for the recovery of the minor actinides and the transuranic elements (TRU's) from a molten salt electrolyte. The process involves placing the device, an electrically non-conducting barrier between an anode salt and a cathode salt. The porous barrier allows uranium to diffuse between the anode and cathode, yet slows the diffusion of uranium ions so as to cause depletion of uranium ions in the catholyte. This allows for the eventual preferential deposition of transuranics present in spent nuclear fuel such as Np, Pu, Am, Cm. The device also comprises an uranium oxidation anode. The oxidation anode is solid uranium metal in the form of spent nuclear fuel. The spent fuel is placed in a ferric metal anode basket which serves as the electrical lead or contact between the molten electrolyte and the anodic uranium metal.

Porous membrane electrochemical cell for uranium and transuranic recovery from molten salt electrolyte

DOEpatents

Willit, James L [Batavia, IL

2010-09-21

An improved process and device for the recovery of the minor actinides and the transuranic elements (TRU's) from a molten salt electrolyte. The process involves placing the device, an electrically non-conducting barrier between an anode salt and a cathode salt. The porous barrier allows uranium to diffuse between the anode and cathode, yet slows the diffusion of uranium ions so as to cause depletion of uranium ions in the catholyte. This allows for the eventual preferential deposition of transuranics present in spent nuclear fuel such as Np, Pu, Am, Cm. The device also comprises an uranium oxidation anode. The oxidation anode is solid uranium metal in the form of spent nuclear fuel. The spent fuel is placed in a ferric metal anode basket which serves as the electrical lead or contact between the molten electrolyte and the anodic uranium metal.

A Silica-Aerogel-Reinforced Composite Polymer Electrolyte with High Ionic Conductivity and High Modulus.

PubMed

Lin, Dingchang; Yuen, Pak Yan; Liu, Yayuan; Liu, Wei; Liu, Nian; Dauskardt, Reinhold H; Cui, Yi

2018-06-25

High-energy all-solid-state lithium (Li) batteries have great potential as next-generation energy-storage devices. Among all choices of electrolytes, polymer-based systems have attracted widespread attention due to their low density, low cost, and excellent processability. However, they are generally mechanically too weak to effectively suppress Li dendrites and have lower ionic conductivity for reasonable kinetics at ambient temperature. Herein, an ultrastrong reinforced composite polymer electrolyte (CPE) is successfully designed and fabricated by introducing a stiff mesoporous SiO 2 aerogel as the backbone for a polymer-based electrolyte. The interconnected SiO 2 aerogel not only performs as a strong backbone strengthening the whole composite, but also offers large and continuous surfaces for strong anion adsorption, which produces a highly conductive pathway across the composite. As a consequence, a high modulus of ≈0.43 GPa and high ionic conductivity of ≈0.6 mS cm -1 at 30 °C are simultaneously achieved. Furthermore, LiFePO 4 -Li full cells with good cyclability and rate capability at ambient temperature are obtained. Full cells with cathode capacity up to 2.1 mAh cm -2 are also demonstrated. The aerogel-reinforced CPE represents a new design principle for solid-state electrolytes and offers opportunities for future all-solid-state Li batteries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-Performance Flexible Solid-State Supercapacitor with an Extended Nanoregime Interface through in Situ Polymer Electrolyte Generation.

PubMed

Anothumakkool, Bihag; Torris A T, Arun; Veeliyath, Sajna; Vijayakumar, Vidyanand; Badiger, Manohar V; Kurungot, Sreekumar

2016-01-20

Here, we report an efficient strategy by which a significantly enhanced electrode-electrolyte interface in an electrode for supercapacitor application could be accomplished by allowing in situ polymer gel electrolyte generation inside the nanopores of the electrodes. This unique and highly efficient strategy could be conceived by judiciously maintaining ultraviolet-triggered polymerization of a monomer mixture in the presence of a high-surface-area porous carbon. The method is very simple and scalable, and a prototype, flexible solid-state supercapacitor could even be demonstrated in an encapsulation-free condition by using the commercial-grade electrodes (thickness = 150 μm, area = 12 cm(2), and mass loading = 7.3 mg/cm(2)). This prototype device shows a capacitance of 130 F/g at a substantially reduced internal resistance of 0.5 Ω and a high capacitance retention of 84% after 32000 cycles. The present system is found to be clearly outperforming a similar system derived by using the conventional polymer electrolyte (PVA-H3PO4 as the electrolyte), which could display a capacitance of only 95 F/g, and this value falls to nearly 50% in just 5000 cycles. The superior performance in the present case is credited primarily to the excellent interface formation of the in situ generated polymer electrolyte inside the nanopores of the electrode. Further, the interpenetrated nature of the polymer also helps the device to show a low electron spin resonance and power rate and, most importantly, excellent shelf-life in the unsealed flexible conditions. Because the nature of the electrode-electrolyte interface is the major performance-determining factor in the case of many electrochemical energy storage/conversion systems, along with the supercapacitors, the developed process can also find applications in preparing electrodes for the devices such as lithium-ion batteries, metal-air batteries, polymer electrolyte membrane fuel cells, etc.

Means of introducing an analyte into liquid sampling atmospheric pressure glow discharge

DOEpatents

Marcus, R. Kenneth; Quarles, Jr., Charles Derrick; Russo, Richard E.; Koppenaal, David W.; Barinaga, Charles J.; Carado, Anthony J.

2017-01-03

A liquid sampling, atmospheric pressure, glow discharge (LS-APGD) device as well as systems that incorporate the device and methods for using the device and systems are described. The LS-APGD includes a hollow capillary for delivering an electrolyte solution to a glow discharge space. The device also includes a counter electrode in the form of a second hollow capillary that can deliver the analyte into the glow discharge space. A voltage across the electrolyte solution and the counter electrode creates the microplasma within the glow discharge space that interacts with the analyte to move it to a higher energy state (vaporization, excitation, and/or ionization of the analyte).

Durable electrooptic devices comprising ionic liquids

DOEpatents

Agrawal, Anoop; Cronin, John P.; Tonazzi, Juan C. L.; Warner, Benjamin P.; McCleskey, T. Mark; Burrell, Anthony K.

2005-11-01

Electrolyte solutions for electrochromic devices such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF3SO3-), bis(trifluoromethylsulfonyl)imide ((CF3SO2)2N-), bis(perfluoroethylsulfonyl)imide ((CF3CF2SO2)2N-) and tris(trifluoromethylsulfonyl)methide ((CF3SO2)3C-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes.

Enzyme-modified electrolyte-gated organic field-effect transistors

NASA Astrophysics Data System (ADS)

Buth, Felix; Donner, Andreas; Stutzmann, Martin; Garrido, Jose A.

2012-10-01

Organic solution-gated field-effect transistors (SGFETs) can be operated at low voltages in aqueous environments, paving the way to the use of organic semiconductors in bio-sensing applications. However, it has been shown that these devices exhibit only a rather weak sensitivity to standard electrolyte parameters such as pH and ionic strength. In order to increase the sensitivity and to add specificity towards a given analyte, the covalent attachment of functional groups and enzymes to the device surface would be desirable. In this contribution we demonstrate that enzyme modified organic SGFETs can be used for the in-situ detection of penicillin in the low μM regime. In a first step, silane molecules with amine terminal groups are grafted to α-sexithiophene-based thin film transistors. Surface characterization techniques like X-ray photoemission confirm the modification of the surface with these functional groups, which are stable in standard aqueous electrolytes. We show that the presence of surface-bound amphoteric groups (e.g. amino or carboxylic moieties) increases the pH-sensitivity of the organic SGFETs. In addition, these groups serve as anchoring sites for the attachment of the enzyme penicillinase. The resulting enzyme-FETs are used for the detection of penicillin, enabling the study of the influence of the buffer strength and the pH of the electrolyte on the enzyme kinetics. The functionalization of the organic FETs shown here can be extended to a large variety of enzymes, allowing the specific detection of different chemical and biochemical analytes.

Estimation of energy density of Li-S batteries with liquid and solid electrolytes

NASA Astrophysics Data System (ADS)

Li, Chunmei; Zhang, Heng; Otaegui, Laida; Singh, Gurpreet; Armand, Michel; Rodriguez-Martinez, Lide M.

2016-09-01

With the exponential growth of technology in mobile devices and the rapid expansion of electric vehicles into the market, it appears that the energy density of the state-of-the-art Li-ion batteries (LIBs) cannot satisfy the practical requirements. Sulfur has been one of the best cathode material choices due to its high charge storage (1675 mAh g-1), natural abundance and easy accessibility. In this paper, calculations are performed for different cell design parameters such as the active material loading, the amount/thickness of electrolyte, the sulfur utilization, etc. to predict the energy density of Li-S cells based on liquid, polymeric and ceramic electrolytes. It demonstrates that Li-S battery is most likely to be competitive in gravimetric energy density, but not volumetric energy density, with current technology, when comparing with LIBs. Furthermore, the cells with polymer and thin ceramic electrolytes show promising potential in terms of high gravimetric energy density, especially the cells with the polymer electrolyte. This estimation study of Li-S energy density can be used as a good guidance for controlling the key design parameters in order to get desirable energy density at cell-level.

21 CFR 862.1655 - Pyruvic acid test system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... treatment of acid-base and electrolyte disturbances or anoxia (the reduction of oxygen in body tissues). (b... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pyruvic acid test system. 862.1655 Section 862....1655 Pyruvic acid test system. (a) Identification. A pyruvic acid test system is a device intended to...

21 CFR 862.1655 - Pyruvic acid test system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... treatment of acid-base and electrolyte disturbances or anoxia (the reduction of oxygen in body tissues). (b... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pyruvic acid test system. 862.1655 Section 862....1655 Pyruvic acid test system. (a) Identification. A pyruvic acid test system is a device intended to...

21 CFR 862.1655 - Pyruvic acid test system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... treatment of acid-base and electrolyte disturbances or anoxia (the reduction of oxygen in body tissues). (b... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pyruvic acid test system. 862.1655 Section 862....1655 Pyruvic acid test system. (a) Identification. A pyruvic acid test system is a device intended to...

21 CFR 862.1655 - Pyruvic acid test system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... treatment of acid-base and electrolyte disturbances or anoxia (the reduction of oxygen in body tissues). (b... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pyruvic acid test system. 862.1655 Section 862....1655 Pyruvic acid test system. (a) Identification. A pyruvic acid test system is a device intended to...

21 CFR 862.1655 - Pyruvic acid test system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... treatment of acid-base and electrolyte disturbances or anoxia (the reduction of oxygen in body tissues). (b... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pyruvic acid test system. 862.1655 Section 862....1655 Pyruvic acid test system. (a) Identification. A pyruvic acid test system is a device intended to...

Symposium Report. Battery materials : amorphous carbons and polymer electrolytes.

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

Gerald, R. E., II; Chemical Engineering

2000-01-01

The motivation for research in battery materials lies in the expanding consumer demand for compact, high-energy density power sources for portable electronic devices, and environmental issues such as global warming and air pollution that have provided the impetus for mass transportation by electric vehicles. The Battery Materials Symposium, chaired by Jacqueline Johnson (ANL), focused on three topics: the structure and electrochemical properties of new and existing electrolytes, devices for fabricating and investigating thin films, and large-scale computer simulations. The symposium opened with a presentation by the author on a recently invented device for in situ investigations of batteries using nuclearmore » magnetic resonance. Joop Schoonman (Delft University) described several methods for preparing and analyzing thin films made of solid electrolytes. These methods included chemical vapor deposition, electrostatic spray deposition and the Solufill process. Aiichiro Nakano discussed large-scale (10 million to 2 billion atoms) computer simulations of polymer and ceramic systems. An overview was given of a DOE Cooperative Research 2000 program, in the initial stages, that was set up to pursue these atomistic simulations. Doug MacFarlane (Monash University) described conductive plastic crystals based on pyrrolidinium imides. Joseph Pluth (U of Chicago) presented his recent crystallographic studies of Pb compounds found in the ubiquitous lead-acid battery. He showed the structures of tribasic lead sulfate and tetrabasic lead sulfate. Austen Angell (Arizona State Univ.) discussed the general problem of electrolyte polarization in Li-ion battery systems with cation transference numbers less than unity. Steven Greenbaum (Hunter College) provided an introduction of NMR interactions that are useful for investigations of lithium-ion battery materials. Analysis by NMR is nuclear specific, probes local environments and dynamics, and is non-destructive. He discussed {sup 7}Li NMR results of a solid electrolyte system composed of LiI dissolved in PEO. Work on oriented polymer electrolyte samples is ongoing. Yuri Andreev (U. of St. Andrews) gave a historical overview of a number of crystal structures of polymer electrolytes solved using XRD in the group of Peter Bruce. The last speaker of the symposium was Peter Papanek (U. of Pennsylvania). He spoke about various disordered carbon materials used as anodes in Li-ion batteries. He also described his inelastic neutron scattering studies of carbon materials derived from pyrolyzed epoxy novolak resins. His data supports the graphene sheet model and is also consistent with calculations of interior and edge carbon atoms in pyrene that chemically reacted with lithium.« less

Graphene-based in-plane micro-supercapacitors with high power and energy densities

PubMed Central

Wu, Zhong–Shuai; Parvez, Khaled; Feng, Xinliang; Müllen, Klaus

2013-01-01

Micro-supercapacitors are important on-chip micro-power sources for miniaturized electronic devices. Although the performance of micro-supercapacitors has been significantly advanced by fabricating nanostructured materials, developing thin-film manufacture technologies and device architectures, their power or energy densities remain far from those of electrolytic capacitors or lithium thin-film batteries. Here we demonstrate graphene-based in-plane interdigital micro-supercapacitors on arbitrary substrates. The resulting micro-supercapacitors deliver an area capacitance of 80.7 μF cm−2 and a stack capacitance of 17.9 F cm−3. Further, they show a power density of 495 W cm−3 that is higher than electrolytic capacitors, and an energy density of 2.5 mWh cm−3 that is comparable to lithium thin-film batteries, in association with superior cycling stability. Such microdevices allow for operations at ultrahigh rate up to 1,000 V s−1, three orders of magnitude higher than that of conventional supercapacitors. Micro-supercapacitors with an in-plane geometry have great promise for numerous miniaturized or flexible electronic applications. PMID:24042088

Graphene-based in-plane micro-supercapacitors with high power and energy densities.

PubMed

Wu, Zhong-Shuai; Parvez, Khaled; Feng, Xinliang; Müllen, Klaus

2013-01-01

Micro-supercapacitors are important on-chip micro-power sources for miniaturized electronic devices. Although the performance of micro-supercapacitors has been significantly advanced by fabricating nanostructured materials, developing thin-film manufacture technologies and device architectures, their power or energy densities remain far from those of electrolytic capacitors or lithium thin-film batteries. Here we demonstrate graphene-based in-plane interdigital micro-supercapacitors on arbitrary substrates. The resulting micro-supercapacitors deliver an area capacitance of 80.7 μF cm⁻² and a stack capacitance of 17.9 F cm⁻³. Further, they show a power density of 495 W cm⁻³ that is higher than electrolytic capacitors, and an energy density of 2.5 mWh cm⁻³ that is comparable to lithium thin-film batteries, in association with superior cycling stability. Such microdevices allow for operations at ultrahigh rate up to 1,000 V s⁻¹, three orders of magnitude higher than that of conventional supercapacitors. Micro-supercapacitors with an in-plane geometry have great promise for numerous miniaturized or flexible electronic applications.

Anodically Grown Binder-Free Nickel Hexacyanoferrate Film: Toward Efficient Water Reduction and Hexacyanoferrate Film Based Full Device for Overall Water Splitting.

PubMed

Bui, Hoa Thi; Shrestha, Nabeen K; Khadtare, Shubhangi; Bathula, Chinna D; Giebeler, Lars; Noh, Yong-Young; Han, Sung-Hwan

2017-05-31

One of the challenges in obtaining hydrogen economically by electrochemical water splitting is to identify and substitute cost-effective earth-abundant materials for the traditionally used precious-metal-based water-splitting electrocatalysts. Herein, we report the electrochemical formation of a thin film of nickel-based Prussian blue analogue hexacyanoferrate (Ni-HCF) through the anodization of a nickel substrate in ferricyanide electrolyte. As compared to the traditionally used Nafion-binder-based bulk film, the anodically obtained binder-free Ni-HCF film demonstrates superior performance in the electrochemical hydrogen evolution reaction (HER), which is highly competitive with that shown by a Pt-plate electrode. The HER onset and the benchmark cathodic current density of 10 mA cm -2 were achieved at small overpotentials of 15 mV and 0.2 V (not iR-corrected), respectively, in 1 M KOH electrolyte, together with the long-term electrochemical durability of the film. Further, a metal-HCF-electrode-based full water-splitting device consisting of the binder-free Ni-HCF film on a Ni plate and a one-dimensional Co-HCF film on carbon paper as the electrodes for the HER and the oxygen evolution reaction (OER), respectively, was designed and was found to demonstrate very promising performance for overall water splitting.

Cosolvent electrolytes for electrochemical devices

DOEpatents

Wessells, Colin Deane; Firouzi, Ali; Motallebi, Shahrokh; Strohband, Sven

2018-01-23

A method for stabilizing electrodes against dissolution and/or hydrolysis including use of cosolvents in liquid electrolyte batteries for three purposes: the extension of the calendar and cycle life time of electrodes that are partially soluble in liquid electrolytes, the purpose of limiting the rate of electrolysis of water into hydrogen and oxygen as a side reaction during battery operation, and for the purpose of cost reduction.

Cosolvent electrolytes for electrochemical devices

DOEpatents

Wessells, Colin Deane; Firouzi, Ali; Motallebi, Shahrokh; Strohband, Sven

2018-02-13

A system and method for stabilizing electrodes against dissolution and/or hydrolysis including use of cosolvents in liquid electrolyte batteries for three purposes: the extension of the calendar and cycle life time of electrodes that are partially soluble in liquid electrolytes, the purpose of limiting the rate of electrolysis of water into hydrogen and oxygen as a side reaction during battery operation, and for the purpose of cost reduction.

Cosolvent electrolytes for electrochemical devices

DOEpatents

Wessells, Colin Deane; Firouzi, Ali; Motallebi, Shahrokh; Strohband, Sven

2018-05-15

A system and method for stabilizing electrodes against dissolution and/or hydrolysis including use of cosolvents in liquid electrolyte batteries for three purposes: the extension of the calendar and cycle life time of electrodes that are partially soluble in liquid electrolytes, the purpose of limiting the rate of electrolysis of water into hydrogen and oxygen as a side reaction during battery operation, and for the purpose of cost reduction.

Ionic liquids, electrolyte solutions including the ionic liquids, and energy storage devices including the ionic liquids

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

Gering, Kevin L.; Harrup, Mason K.; Rollins, Harry W.

2015-12-08

An ionic liquid including a phosphazene compound that has a plurality of phosphorus-nitrogen units and at least one pendant group bonded to each phosphorus atom of the plurality of phosphorus-nitrogen units. One pendant group of the at least one pendant group comprises a positively charged pendant group. Additional embodiments of ionic liquids are disclosed, as are electrolyte solutions and energy storage devices including the embodiments of the ionic liquid.

Portable probe to measure sensitization of stainless steel

DOEpatents

Park, Jang Y.

1979-01-01

An electrochemical cell for making field measurements of metals such as stainless steel comprises a cylinder containing a reservoir of an electrolyte, a reference electrode, a capillary tube connecting the electrolyte to the surface of the metal to be measured and another electrode in electrical contact with the electrolyte. External connections from the reference electrode, the other electrode, and the sample to a measuring device provide means for maintaining the potential of the electrolyte while sweeping the potential difference between the electrolyte and the metal. Such a sweep enables the determination of a current-voltage characteristic that is a measure of sensitization in the metal.

Investigating anomalous transport of electrolytes in charged porous media

NASA Astrophysics Data System (ADS)

Skjøde Bolet, Asger Johannes; Mathiesen, Joachim

2017-04-01

Surface charge is know to play an important role in microfluidics devices when dealing with electrolytes and their transport properties. Similarly, surface charge could play a role for transport in porous rock with submicron pore sizes. Estimates of the streaming potentials and electro osmotic are mostly considered in simple geometries both using analytic and numerical tools, however it is unclear at present how realistic complex geometries will modify the dynamics. Our work have focused on doing numerical studies of the full three-dimensional Stokes-Poisson-Nernst-Planck problem for electrolyte transport in porous rock. As the numerical implementation, we have used a finite element solver made using the FEniCS project code base, which can both solve for a steady state configuration and the full transient. In the presentation, we will show our results on anomalous transport due to electro kinetic effects such as the streaming potential or the electro osmotic effect.

A study of electrochemical devices based on Agar-Agar-NH4I biopolymer electrolytes

NASA Astrophysics Data System (ADS)

Selvalakshmi, S.; Mathavan, T.; Selvasekarapandian, S.; Premalatha, M.

2018-04-01

A polymer electrolyte system has been developed using a biopolymer namely, Agar-Agar in combination with ammonium iodide in different weight percentages by solution casting technique. The films were characterized electrically by AC Impedance Spectroscopy for its conductivity. The highest conductivity achieved at room temperature was for 50 wt. % agar-agar: 50 wt. % NH4I with a conductivity value of 1.20 × 10-4 Scm-1. An electrochemical cell was fabricated in the configuration of: Zn + ZnSO4.7H2O + graphite (anode) | 50 wt. % (Agar-agar): 50 wt. % NH4I (electrolyte) | PbO2 + V2O5 + graphite (cathode) and it produced a maximum open circuit voltage of 1.73 V. A single PEM fuel cell was constructed with the highest conducting sample (50 wt. % (Agar-agar): 50 wt. % NH4I) and it exhibited an output voltage of 408mV.

Electrolytic orthoborate salts for lithium batteries

DOEpatents

Angell, Charles Austen [Mesa, AZ; Xu, Wu [Tempe, AZ

2008-01-01

Orthoborate salts suitable for use as electrolytes in lithium batteries and methods for making the electrolyte salts are provided. The electrolytic salts have one of the formulae (I). In this formula anionic orthoborate groups are capped with two bidentate chelating groups, Y1 and Y2. Certain preferred chelating groups are dibasic acid residues, most preferably oxalyl, malonyl and succinyl, disulfonic acid residues, sulfoacetic acid residues and halo-substituted alkylenes. The salts are soluble in non-aqueous solvents and polymeric gels and are useful components of lithium batteries in electrochemical devices.

Electrolytic orthoborate salts for lithium batteries

DOEpatents

Angell, Charles Austen [Mesa, AZ; Xu, Wu [Tempe, AZ

2009-05-05

Orthoborate salts suitable for use as electrolytes in lithium batteries and methods for making the electrolyte salts are provided. The electrolytic salts have one of the formulae (I). In this formula anionic orthoborate groups are capped with two bidentate chelating groups, Y1 and Y2. Certain preferred chelating groups are dibasic acid residues, most preferably oxalyl, malonyl and succinyl, disulfonic acid residues, sulfoacetic acid residues and halo-substituted alkylenes. The salts are soluble in non-aqueous solvents and polymeric gels and are useful components of lithium batteries in electrochemical devices.

Optimisation of oxygen ion transport in materials for ceramic membrane devices.

PubMed

Kilner, J A

2007-01-01

Oxygen transport in ceramic oxide materials has received much attention over the past few decades. Much of this interest has stemmed from the desire to construct high temperature electrochemical devices for energy conversion, an example being the solid oxide fuel cell. In order to achieve high performance for these devices, insights are needed in how to achieve optimum performance from the functional components such as the electrolytes and electrodes. This includes the optimisation of oxygen transport through the crystal lattice of electrode and electrolyte materials and across the homogeneous (grain boundary) and heterogeneous interfaces that exist in real devices. Strategies are discussed for the optimisation of these quantities and current problems in the characterisation of interfacial transport are explored.

High performance solid-state electric double layer capacitor from redox mediated gel polymer electrolyte and renewable tamarind fruit shell derived porous carbon.

PubMed

Senthilkumar, S T; Selvan, R Kalai; Melo, J S; Sanjeeviraja, C

2013-11-13

The activated carbon was derived from tamarind fruit shell and utilized as electrodes in a solid state electrochemical double layer capacitor (SSEDLC). The fabricated SSEDLC with PVA (polyvinyl alcohol)/H2SO4 gel electrolyte delivered high specific capacitance and energy density of 412 F g(-1) and 9.166 W h kg(-1), respectively, at 1.56 A g(-1). Subsequently, Na2MoO4 (sodium molybdate) added PVA/H2SO4 gel electrolyte was also prepared and applied for SSEDLC, to improve the performance. Surprisingly, 57.2% of specific capacitance (648 F g(-1)) and of energy density (14.4 Wh kg(-1)) was increased while introducing Na2MoO4 as the redox mediator in PVA/H2SO4 gel electrolyte. This improved performance is owed to the redox reaction between Mo(VI)/Mo(V) and Mo(VI)/Mo(IV) redox couples in Na2MoO4/PVA/H2SO4 gel electrolyte. Similarly, the fabricated device shows the excellent capacitance retention of 93% for over 3000 cycles. The present work suggests that the Na2MoO4 added PVA/H2SO4 gel is a potential electrolyte to improve the performance instead of pristine PVA/H2SO4 gel electrolyte. Based on the overall performance, it is strongly believed that the combination of tamarind fruit shell derived activated carbon and Na2MoO4/PVA/H2SO4 gel electrolyte is more attractive in the near future for high performance SSEDLCs.

Electrochromic devices

DOEpatents

Allemand, Pierre M.; Grimes, Randall F.; Ingle, Andrew R.; Cronin, John P.; Kennedy, Steve R.; Agrawal, Anoop; Boulton, Jonathan M.

2001-01-01

An electrochromic device is disclosed having a selective ion transport layer which separates an electrochemically active material from an electrolyte containing a redox active material. The devices are particularly useful as large area architectural and automotive glazings due to there reduced back reaction.

Hydrophobic interaction and charge accumulation at the diamond-electrolyte interface.

PubMed

Dankerl, M; Lippert, A; Birner, S; Stützel, E U; Stutzmann, M; Garrido, J A

2011-05-13

The hydrophobic interaction of surfaces with water is a well-known phenomenon, but experimental evidence of its influence on biosensor devices has been lacking. In this work we investigate diamond field-effect devices, reporting on Hall effect experiments and complementary simulations of the interfacial potential at the hydrogen-terminated diamond/aqueous electrolyte interface. The interfacial capacitance, derived from the gate-dependent Hall carrier concentration, can be modeled only when considering the hydrophobic nature of this surface and its influence on the structure of interfacial water. Our work demonstrates how profoundly the performance of potentiometric biosensor devices can be affected by their surfaces' hydrophobicity.

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

NASA Astrophysics Data System (ADS)

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

2018-02-01

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

Electric double-layer capacitor based on an ionic clathrate hydrate.

PubMed

Lee, Wonhee; Kwon, Minchul; Park, Seongmin; Lim, Dongwook; Cha, Jong-Ho; Lee, Huen

2013-07-01

Herein, we suggest a new approach to an electric double-layer capacitor (EDLC) that is based on a proton-conducting ionic clathrate hydrate (ICH). The ice-like structures of clathrate hydrates, which are comprised of host water molecules and guest ions, make them suitable for applications in EDLC electrolytes, owing to their high proton conductivities and thermal stabilities. The carbon materials in the ICH Me4NOH⋅5 H2O show a high specific capacitance, reversible charge-discharge behavior, and a long cycle life. The ionic-hydrate complex provides the following advantages in comparison with conventional aqueous and polymer electrolytes: 1) The ICH does not cause leakage problems under normal EDLC operating conditions. 2) The hydrate material can be utilized itself, without requiring any pre-treatments or activation for proton conduction, thus shortening the preparation procedure of the EDLC. 3) The crystallization of the ICH makes it possible to tailor practical EDLC dimensions because of its fluidity as a liquid hydrate. 4) The hydrate solid electrolyte exhibits more-favorable electrochemical stability than aqueous and polymer electrolytes. Therefore, ICH materials are expected to find practical applications in versatile energy devices that incorporate electrochemical systems. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation of electrolyte leaching in the performance degradation of phosphoric acid-doped polybenzimidazole membrane-based high temperature fuel cells

NASA Astrophysics Data System (ADS)

Jeong, Yeon Hun; Oh, Kyeongmin; Ahn, Sungha; Kim, Na Young; Byeon, Ayeong; Park, Hee-Young; Lee, So Young; Park, Hyun S.; Yoo, Sung Jong; Jang, Jong Hyun; Kim, Hyoung-Juhn; Ju, Hyunchul; Kim, Jin Young

2017-09-01

Precise monitoring of electrolyte leaching in high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) devices during lifetime tests is helpful in making a diagnosis of their quality changes and analyzing their electrochemical performance degradation. Here, we investigate electrolyte leaching in the performance degradation of phosphoric acid (PA)-doped polybenzimidazole (PBI) membrane-based HT-PEMFCs. We first perform quantitative analyses to measure PA leakage during cell operation by spectrophotometric means, and a higher PA leakage rate is detected when the current density is elevated in the cell. Second, long-term degradation tests under various current densities of the cells and electrochemical impedance spectroscopy (EIS) analysis are performed to examine the influence of PA loss on the membrane and electrodes during cell performance degradation. The combined results indicate that PA leakage affect cell performance durability, mostly due to an increase in charge transfer resistance and a decrease in the electrochemical surface area (ECSA) of the electrodes. Additionally, a three-dimensional (3-D) HT-PEMFC model is applied to a real-scale experimental cell, and is successfully validated against the polarization curves measured during various long-term experiments. The simulation results highlight that the PA loss from the cathode catalyst layer (CL) is a significant contributor to overall performance degradation.

Current status of solid-state lithium batteries employing solid redox polymerization cathodes

NASA Astrophysics Data System (ADS)

Visco, S. J.; Doeff, M. M.; Dejonghe, L. C.

1991-03-01

The rapidly growing demand for secondary batteries having high specific energy and power has naturally led to increased efforts in lithium battery technology. Still, the increased safety risks associated with high energy density systems has tempered the enthusiasm of proponents of such systems for use in the consumer marketplace. The inherent advantages of all-solid-state batteries in regards to safety and reliability are strong factors in advocating their introduction to the marketplace. However, the low ionic conductivity of solid electrolytes relative to nonaqueous liquid electrolytes implies low power densities for solid state systems operating at ambient temperatures. Recent advances in polymer electrolytes have led to the introduction of solid electrolytes having conductivities in the range of 10(exp -4)/ohm cm at room temperature; this is still two orders of magnitude lower than liquid electrolytes. Although these improved ambient conductivities put solid state batteries in the realm of practical devices, it is clear that solid state batteries using such polymeric separators will be thin film devices. Fortunately, thin film fabrication techniques are well established in the plastics and paper industry, and present the possibility of continuous web-form manufacturing. This style of battery manufacture should make solid polymer batteries very cost-competitive with conventional secondary cells. In addition, the greater geometric flexibility of thin film solid state cells should provide benefits in terms of the end-use form factor in device design. This work discusses the status of solid redox polymerization cathodes.

Quantum Dot Sensitized Solar Cells Based on Ternary Metal Oxide Nanowires

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

Wang, Wenyong; Tang, Jinke; Dahnovsky, Yuri

In Phase I of this project we investigate quantum dot sensitized solar cells (QDSSCs) based on ternary metal oxide nanowires and study the physical and chemical mechanisms that govern device operation. Our research has the following five objectives: (1) synthesis of ternary metal oxide nanowires, (2) synthesis of QDs and exploration of non-solution based QD deposition methods, (3) physical and electro-optical characterizations of fabricated solar devices, (4) device modeling and first-principle theoretical study of transport physics, and (5) investigation of long-term stability issues of QD sensitized solar cells. In Phase II of this project our first major research goal ismore » to investigate magnetically doped quantum dots and related spin polarization effect, which could improve light absorption and suppress electron relaxation in the QDs. We will utilize both physical and chemical methods to synthesize these doped QDs. We will also study magnetically modified nanowires and introduce spin-polarized transport into QDSSCs, and inspect its impact on forward electron injection and back electron transfer processes. Our second goal is to study novel solid-state electrolytes for QDSSCs. Specifically, we will inspect a new type of polymer electrolytes based on a modified polysulfide redox couple, and examine the effect of their electrical properties on QDSSC performance. These solid-state electrolytes could also be used as filler materials for in situ sample fracturing in STM and enable cross-sectional interface examination of QD/nanowire structures. Our third research goal is to examine the interfacial properties such as energy level alignment at QD/nanowire interfaces using the newly developed Cross-sectional Scanning Tunneling Microscopy and Spectroscopy technique for non-cleavable materials. This technique allows a direct probing of band structures and alignment at device interfaces, which could generate important insight into the mechanisms that govern QDSSC operation. These investigations will be carried out through a close collaboration between our experimental and theoretical efforts in this project. This project initiates an important research direction in the jurisdiction of Wyoming. It brings together researchers from different academic disciplines including physics, chemistry, materials science, and engineering to work on one common scientific theme, and is a vital step towards the establishment of an nationally competitive research program in energy-related nanomaterials in the state of Wyoming.« less

High efficiency graphene coated copper based thermocells connected in series

NASA Astrophysics Data System (ADS)

Sindhuja, Mani; Indubala, Emayavaramban; Sudha, Venkatachalam; Harinipriya, Seshadri

2018-04-01

Conversion of low-grade waste heat into electricity had been studied employing single thermocell or flowcells so far. Graphene coated copper electrodes based thermocells connected in series displayed relatively high efficiency of thermal energy harvesting. The maximum power output of 49.2W/m2 for normalized cross sectional electrode area is obtained at 60ºC of inter electrode temperature difference. The relative carnot efficiency of 20.2% is obtained from the device. The importance of reducing the mass transfer and ion transfer resistance to improve the efficiency of the device is demonstrated. Degradation studies confirmed mild oxidation of copper foil due to corrosion caused by the electrolyte.

Alkaline Capacitors Based on Nitride Nanoparticles

NASA Technical Reports Server (NTRS)

Aldissi, Matt

2003-01-01

High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition- metal nitrides (in particular, Fe3N and TiN) offer a desirable combination of high electrical conductivity and electrochemical stability in aqueous alkaline electrolytes like KOH. The high energy densities of these capacitors are attributable mainly to their high capacitance densities, which, in turn, are attributable mainly to the large specific surface areas of the electrode nanoparticles. Capacitors of this type could be useful as energy-storage components in such diverse equipment as digital communication systems, implanted medical devices, computers, portable consumer electronic devices, and electric vehicles.

Electrochemical device for converting carbon dioxide to a reaction product

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

Masel, Richard I.; Chen, Qingmei; Liu, Zengcai

An electrochemical device converts carbon dioxide to a reaction product. The device includes an anode and a cathode, each comprising a quantity of catalyst. The anode and cathode each has reactant introduced thereto. A polymer electrolyte membrane is interposed between the anode and the cathode. At least a portion of the cathode catalyst is directly exposed to gaseous carbon dioxide during electrolysis. The average current density at the membrane is at least 20 mA/cm.sup.2, measured as the area of the cathode gas diffusion layer that is covered by catalyst, and CO selectivity is at least 50% at a cell potentialmore » of 3.0 V. In some embodiments, the polymer electrolyte membrane comprises a polymer in which a constituent monomer is (p-vinylbenzyl)-R, where R is selected from the group consisting of imidazoliums, pyridiniums and phosphoniums. In some embodiments, the polymer electrolyte membrane is a Helper Membrane comprising a polymer containing an imidazolium ligand, a pyridinium ligand, or a phosphonium ligand.« less

Structure-Property Relationships of Organic Electrolytes and Their Effects on Li/S Battery Performance.

PubMed

Kaiser, Mohammad Rejaul; Chou, Shulei; Liu, Hua-Kun; Dou, Shi-Xue; Wang, Chunsheng; Wang, Jiazhao

2017-12-01

Electrolytes, which are a key component in electrochemical devices, transport ions between the sulfur/carbon composite cathode and the lithium anode in lithium-sulfur batteries (LSBs). The performance of a LSB mostly depends on the electrolyte due to the dissolution of polysulfides into the electrolyte, along with the formation of a solid-electrolyte interphase. The selection of the electrolyte and its functionality during charging and discharging is intricate and involves multiple reactions and processes. The selection of the proper electrolyte, including solvents and salts, for LSBs strongly depends on its physical and chemical properties, which is heavily controlled by its molecular structure. In this review, the fundamental properties of organic electrolytes for LSBs are presented, and an attempt is made to determine the relationship between the molecular structure and the properties of common organic electrolytes, along with their effects on the LSB performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An experimental study on PEO polymer electrolyte based all-solid-state supercapacitor

NASA Astrophysics Data System (ADS)

Yijing, Yin

Supercapacitors are one of the most important electrochemical energy storage and conversion devices, however low ionic conductivity of solid state polymer electrolytes and the poor accessibility of the ions to the active sites in the porous electrode will cause low performance for all-solid-state supercapacitors and will limit their application. The objective of the dissertation is to improve the performance of all-solid-state supercapactor by improving electrolyte conductivity and solving accessibility problem of the ions to the active sites. The low ionic conductivity (10-8 S/cm) of poly(ethylene oxide) (PEO) limits its application as an electrolyte. Since PEO is a semicrystal polymer and the ion conduction take place mainly in the amorphous regions of the PEO/Lithium salt complex, improvements in the percentage of amorphous phase in PEO or increasing the charge carrier concentration and mobility could increase the ionic conductivity of PEO electrolyte. Hot pressing along with the additions of different lithium salts, inorganic fillers and plasticizers were applied to improve the ionic conductivity of PEO polymer electrolytes. Four electrode methods were used to evaluate the conductivity of PEO based polymer electrolytes. Results show that adding certain lithium salts, inorganic fillers, and plasticizers could improve the ionic conductivity of PEO electrolytes up 10-4 S/cm. Further hot pressing treatment could improve the ionic conductivity of PEO electrolytes up to 10-3 S/cm. The conductivity improvement after hot pressing treatment is elucidated as that the spherulite crystal phase is convert into the fringed micelle crystal phase or the amorphous phase of PEO electrolytes. PEO electrolytes were added into active carbon as a binder and an ion conductor, so as to provide electrodes with not only ion conduction, but also the accessibility of ion to the active sites of electrodes. The NaI/I 2 mediator was added to improve the conductivity of PEO electrolyte and provide pseudocapacitance for all-solid-state supercapacitors. Impedance, cyclic voltammetry, and gavalnostatic charge/discharge measurements were conducted to evaluate the electrochemical performance of PEO polymer electrolytes based all-solid-state supercapacitors. Results demonstrate that the conductivity of PEO electrolyte could be improved to 0.1 S/cm with a mediator concentration of 50wt%. A high conductivity in the PEO electrolyte with mediator is an indication of a high electron exchange rate between the mediator and mediator. The high electron exchange rates at mediator carbon interface and between mediator and mediator are essential in order to obtain a high response rate and high power. This automatically solves the accessibility problem. With the addition of NaI/I2 mediator, the specific capacitance increased more than 30 folds, specific power increased almost 20 folds, and specific energy increased around 10 folds. Further addition of filler to the electrodes along with the mediator could double the specific capacitor and specific power of the all-solid-state supercapacitor. The stability of the corresponded supercapacitor is good within 2000 cycles.

Small CO2 Sensors Operate at Lower Temperature

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Xu, Jennifer C.

2009-01-01

Solid-electrolyte-based amperometric sensors for measuring concentrations of CO2 in air are being developed for use in detection of fires, environmental monitoring, and other applications where liquid-based electrochemical cells are problematic. These sensors are small (sizes of the order of a millimeter), are robust, are amenable to batch fabrication at relatively low cost, and exhibit short response times (seconds) and wide detection ranges. A sensor of this type at a previous stage of development included a solid electrolyte of Na3Zr2Si2PO12 deposited mainly between interdigitated Pt electrodes on an alumina substrate, all overcoated with an auxiliary solid electrolyte of (Na2CO3:BaCO3 in a molar ratio of 1:1.7). It was necessary to heat this device to a temperature as high as 600 C to obtain the desired sensitivity and rapid response. Heating sensors increases the power consumption of the sensor system and complicates the use of the sensor in some applications. Thus, decreasing a sensor s power consumption while maintaining its performance is a technical goal of ongoing development.

Non-aqueous electrolyte for lithium-ion battery

DOEpatents

Zhang, Lu; Zhang, Zhengcheng; Amine, Khalil

2014-04-15

The present technology relates to stabilizing additives and electrolytes containing the same for use in electrochemical devices such as lithium ion batteries and capacitors. The stabilizing additives include triazinane triones and bicyclic compounds comprising succinic anhydride, such as compounds of Formulas I and II described herein.

Comparative study of polymer and liquid electrolytes in quantum dot sensitized solar cells

NASA Astrophysics Data System (ADS)

Poudyal, Uma; Wang, Wenyong

We present the study of CdS/CdSe quantum dot sensitized solar cells (QDSSCs) in which Zn2SnO4\\ nanowires on the conductive glass are used as photoanode. The CdS/CdSe quantum dots (QDs) are deposited in the Zn2SnO4 photoanode by the Successive Ionic Layer Adsorption and Reaction (SILAR) method. CdS is first deposited on the nanowires after which it is further coated with 5 cycles of CdSe QDs. Finally, ZnS is coated on the QDs as a passivation layer. The QD sensitized photoanode are then used to assemble a solar device with the polymer and liquid electrolytes. The Incident Photon to Current Efficiency (IPCE) spectra are obtained for the CdS/CdSe coated nanowires. Further, a stability test of these devices is performed, using the polymer and liquid electrolytes, which provides insight to determine the better working electrolyte in the CdS/CdSe QDSSCs. Department of Energy.

Improved Performance of Ionic Liquid Supercapacitors by using Tetracyanoborate Anions.

PubMed

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

2018-02-01

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

BIPV-powered smart windows utilizing photovoltaic and electrochromic devices.

PubMed

Ma, Rong-Hua; Chen, Yu-Chia

2012-01-01

A BIPV-powered smart window comprising a building-integrated photovoltaic (BIPV) panel and an all-solid-state electrochromic (EC) stack is proposed. In the proposed device, the output voltage of the BIPV panel varies in accordance with the intensity of the incident light and is modulated in such a way as to generate the EC stack voltage required to maintain the indoor illuminance within a specified range. Two different EC stacks are fabricated and characterized, namely one stack comprising ITO/WO(3)/Ta(2)O(5)/ITO and one stack comprising ITO/WO(3)/lithium-polymer electrolyte/ITO. It is shown that of the two stacks, the ITO/WO(3)/lithium-polymer electrolyte/ITO stack has a larger absorptance (i.e., approximately 99% at a driving voltage of 3.5 V). The experimental results show that the smart window incorporating an ITO/WO(3)/lithium-polymer electrolyte/ITO stack with an electrolyte thickness of 1.0 μm provides an indoor illuminance range of 750-1,500 Lux under typical summertime conditions in Taiwan.

Transcap: A new integrated hybrid supercapacitor and electrolyte-gated transistor device (Presentation Recording)

NASA Astrophysics Data System (ADS)

Santato, Clara

2015-10-01

The boom in multifunctional, flexible, and portable electronics and the increasing need of low-energy cost and autonomy for applications ranging from wireless sensor networks for smart environments to biomedical applications are triggering research efforts towards the development of self-powered sustainable electronic devices. Within this context, the coupling of electronic devices (e.g. sensors, transistors) with small size energy storage systems (e.g. micro-batteries or micro-supercapacitors) is actively pursued. Micro-electrochemical supercapacitors are attracting much attention in electronics for their capability of delivering short power pulses with high stability over repeated charge/discharge cycling. For their high specific pseudocapacitance, electronically conducting polymers are well known as positive materials for hybrid supercapacitors featuring high surface carbon negative electrodes. The processability of both polymer and carbon is of great relevance for the development of flexible miniaturised devices. Electronically conducting polymers are even well known to feature an electronic conductivity that depends on their oxidation (p-doped state) and that it is modulated by the polymer potential. This property and the related pseudocapacitive response make polymer very attracting channel materials for electrolyte-gated (EG) transistors. Here, we propose a novel concept of "Trans-capacitor", an integrated device that exhibits the storage properties of a polymer/carbon hybrid supercapacitor and the low-voltage operation of an electrolyte-gated transistor.

A Quasi-Solid-State Li-Ion Capacitor Based on Porous TiO2 Hollow Microspheres Wrapped with Graphene Nanosheets.

PubMed

Wang, Faxing; Wang, Chun; Zhao, Yujuan; Liu, Zaichun; Chang, Zheng; Fu, Lijun; Zhu, Yusong; Wu, Yuping; Zhao, Dongyuan

2016-12-01

The quasi-solid-state Li-ion capacitor is demonstrated with graphene nanosheets prepared by an electrochemical exfoliation as the positive electrode and the porous TiO 2 hollow microspheres wrapped with the same graphene nanosheets as the negative electrode, using a Li-ion conducting gel polymer electrolyte. This device may be the key to bridging the gap between conventional lithium-ion batteries and supercapacitors, meanwhile meeting the safety demands of electronic devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photovoltaic and thermal properties of electrolytes based on electrospun poly(vinylidene fluoride-hexafluoro propylene)/poly(methyl methacrylate) nanofibers for dye-sensitized solar cells.

PubMed

Jang, Young-Wook; Won, Du-Hyun; Kim, Young-Keun; Hwang, Won-Pill; Jang, Sung-Il; Jeong, Sung-Hoon; Kim, Mi-Ra; Lee, Jin-Kook

2014-08-01

We prepared electrospun polymer nanofibers by electrospnning method and investigated about their applications to dye-sensitized solar cells (DSSCs). Electrospun polymer nanofibers applied to the polymer matrix in electrolyte for DSSCs. To improve the stiffness of polymer nanofiber, poly(vinylidene fluoride-hexafluoro propylene)/Poly(methyl methacrylate) (PVDF-HFP/PMMA) blend nanofibers were prepared and examined. In the electrospun PVDF-HFP/PMMA (1:1) blend nanofibers, the best results of VOC, JSC, FF, and efficiency of the DSSC devices showed 0.71 V, 12.8 mA/cm2, 0.61, and 5.56% under AM 1.5 illumination.

Optimization of Design Parameters and Operating Conditions of Electrochemical Capacitors for High Energy and Power Performance

NASA Astrophysics Data System (ADS)

Ike, Innocent S.; Sigalas, Iakovos; Iyuke, Sunny E.

2017-03-01

Theoretical expressions for performance parameters of different electrochemical capacitors (ECs) have been optimized by solving them using MATLAB scripts as well as via the MATLAB R2014a optimization toolbox. The performance of the different kinds of ECs under given conditions was compared using theoretical equations and simulations of various models based on the conditions of device components, using optimal values for the coefficient associated with the battery-kind material ( K BMopt) and the constant associated with the electrolyte material ( K Eopt), as well as our symmetric electric double-layer capacitor (EDLC) experimental data. Estimation of performance parameters was possible based on values for the mass ratio of electrodes, operating potential range ratio, and specific capacitance of electrolyte. The performance of asymmetric ECs with suitable electrode mass and operating potential range ratios using aqueous or organic electrolyte at appropriate operating potential range and specific capacitance was 2.2 and 5.56 times greater, respectively, than for the symmetric EDLC and asymmetric EC using the same aqueous electrolyte, respectively. This enhancement was accompanied by reduced cell mass and volume. Also, the storable and deliverable energies of the asymmetric EC with suitable electrode mass and operating potential range ratios using the proper organic electrolyte were 12.9 times greater than those of the symmetric EDLC using aqueous electrolyte, again with reduced cell mass and volume. The storable energy, energy density, and power density of the asymmetric EDLC with suitable electrode mass and operating potential range ratios using the proper organic electrolyte were 5.56 times higher than for a similar symmetric EDLC using aqueous electrolyte, with cell mass and volume reduced by a factor of 1.77. Also, the asymmetric EDLC with the same type of electrode and suitable electrode mass ratio, working potential range ratio, and proper organic electrolyte showed enhanced performance compared with the conventional symmetric EDLC using aqueous electrolyte, with reduced cell mass and volume. These results can obviously reduce the number of experiments required to determine the optimum manufacturing design for ECs and also demonstrate that use of an asymmetric electrode and organic electrolyte was very successful for improving the performance of the EC, with reduced cell mass and volume. These results can also act as guidelines for design, fabrication, and operation of electrochemical capacitors with outstanding storable energy, energy density, and power density.

Quasi-Solid-State Single-Atom Transistors.

PubMed

Xie, Fangqing; Peukert, Andreas; Bender, Thorsten; Obermair, Christian; Wertz, Florian; Schmieder, Philipp; Schimmel, Thomas

2018-06-21

The single-atom transistor represents a quantum electronic device at room temperature, allowing the switching of an electric current by the controlled and reversible relocation of one single atom within a metallic quantum point contact. So far, the device operates by applying a small voltage to a control electrode or "gate" within the aqueous electrolyte. Here, the operation of the atomic device in the quasi-solid state is demonstrated. Gelation of pyrogenic silica transforms the electrolyte into the quasi-solid state, exhibiting the cohesive properties of a solid and the diffusive properties of a liquid, preventing the leakage problem and avoiding the handling of a liquid system. The electrolyte is characterized by cyclic voltammetry, conductivity measurements, and rotation viscometry. Thus, a first demonstration of the single-atom transistor operating in the quasi-solid-state is given. The silver single-atom and atomic-scale transistors in the quasi-solid-state allow bistable switching between zero and quantized conductance levels, which are integer multiples of the conductance quantum G 0  = 2e 2 /h. Source-drain currents ranging from 1 to 8 µA are applied in these experiments. Any obvious influence of the gelation of the aqueous electrolyte on the electron transport within the quantum point contact is not observed. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of biofouling in stainless microfluidic channels for implantable multilayered dialysis device

NASA Astrophysics Data System (ADS)

Ota, Takashi; To, Naoya; Kanno, Yoshihiko; Miki, Norihisa

2017-06-01

An implantable artificial kidney can markedly improve the quality of life of renal disease patients. Our group has developed an implantable multilayered dialysis system consisting of microfluidic channels and dialysis membranes. Long-term evaluation is necessary for implant devices where biofouling is a critical factor, culminating in the deterioration of dialysis performance. Our previous work revealed that surface conditions, which depend on the manufacturing process, determine the amount of biofouling, and that electrolytic etching is the most suitable technique for forming a channel wall free of biofouling. In this study, we investigated the electrolytic etching conditions in detail. We conducted in vitro experiments for 7 d and evaluated the adhesion of biomaterials by scanning electron microscopy. The experiments revealed that a surface mirror-finished by electrolytic etching effectively prevents biofouling.

Methods for dispensing mercury into devices

DOEpatents

Grossman, Mark W.; George, William A.

1987-04-28

A process for dispensing mercury into devices which requires mercury. Mercury is first electrolytically separated from either HgO or Hg.sub.2 Cl.sub.2 and plated onto a cathode wire. The cathode wire is then placed into a device requiring mercury.

Influence of electrolyte ion-solvent interactions on the performances of supercapacitors porous carbon electrodes

NASA Astrophysics Data System (ADS)

Decaux, C.; Matei Ghimbeu, C.; Dahbi, M.; Anouti, M.; Lemordant, D.; Béguin, F.; Vix-Guterl, C.; Raymundo-Piñero, E.

2014-10-01

The development of advanced and safe electrochemical supercapacitors or hybrid supercapacitors combining a battery electrode material such as graphite and a porous carbon electrode implies the use of new electrolytes containing a tetra-alkylammonium or lithium salt dissolved preferentially in a safe and environmentally friendly solvent such as alkylcarbonates. In those systems, the carbon porosity of the activated carbon electrode controls the electrochemical behavior of the whole device. In this work, it is demonstrated that electrolytes containing highly polarizing ions such as Li+ dissolved in polar solvents such as alkylcarbonates do not completely loss their solvation shell at the opposite of what is observed for poorly solvated cations like TEABF4. As a consequence, the optimal carbon pore size for obtaining the largest energy density, while keeping a high power density, is wider when strongly solvated cations, like Li+ are used than for conventional organic electrolytes using acetonitrile as solvent and TEA+ as salt cations. TEA+ cations are easily desolvated and hence are able to penetrate in small pores matching the dimensions of bare ions. The dissimilarity of behavior of alkylcarbonates and acetonitrile based electrolytes highlights the importance of ion-solvent interactions when searching the optimal porous texture for the electrode material.

Robert Tenent | NREL

Science.gov Websites

improved electrochemical devices, in particular electrochromic windows and lithium ion batteries. At NREL Materials Design and Integration for Electrochromic Devices and Li-ion Batteries Gel/Solid Electrolyte

Study on Zinc Oxide-Based Electrolytes in Low-Temperature Solid Oxide Fuel Cells.

PubMed

Xia, Chen; Qiao, Zheng; Feng, Chu; Kim, Jung-Sik; Wang, Baoyuan; Zhu, Bin

2017-12-28

Semiconducting-ionic conductors have been recently described as excellent electrolyte membranes for low-temperature operation solid oxide fuel cells (LT-SOFCs). In the present work, two new functional materials based on zinc oxide (ZnO)-a legacy material in semiconductors but exceptionally novel to solid state ionics-are developed as membranes in SOFCs for the first time. The proposed ZnO and ZnO-LCP (La/Pr doped CeO₂) electrolytes are respectively sandwiched between two Ni 0.8 Co 0.15 Al 0.05 Li-oxide (NCAL) electrodes to construct fuel cell devices. The assembled ZnO fuel cell demonstrates encouraging power outputs of 158-482 mW cm -2 and high open circuit voltages (OCVs) of 1-1.06 V at 450-550 °C, while the ZnO-LCP cell delivers significantly enhanced performance with maximum power density of 864 mW cm -2 and OCV of 1.07 V at 550 °C. The conductive properties of the materials are investigated. As a consequence, the ZnO electrolyte and ZnO-LCP composite exhibit extraordinary ionic conductivities of 0.09 and 0.156 S cm -1 at 550 °C, respectively, and the proton conductive behavior of ZnO is verified. Furthermore, performance enhancement of the ZnO-LCP cell is studied by electrochemical impedance spectroscopy (EIS), which is found to be as a result of the significantly reduced grain boundary and electrode polarization resistances. These findings indicate that ZnO is a highly promising alternative semiconducting-ionic membrane to replace the electrolyte materials for advanced LT-SOFCs, which in turn provides a new strategic pathway for the future development of electrolytes.

Study on Zinc Oxide-Based Electrolytes in Low-Temperature Solid Oxide Fuel Cells

PubMed Central

Qiao, Zheng; Feng, Chu; Wang, Baoyuan; Zhu, Bin

2017-01-01

Semiconducting-ionic conductors have been recently described as excellent electrolyte membranes for low-temperature operation solid oxide fuel cells (LT-SOFCs). In the present work, two new functional materials based on zinc oxide (ZnO)—a legacy material in semiconductors but exceptionally novel to solid state ionics—are developed as membranes in SOFCs for the first time. The proposed ZnO and ZnO-LCP (La/Pr doped CeO2) electrolytes are respectively sandwiched between two Ni0.8Co0.15Al0.05Li-oxide (NCAL) electrodes to construct fuel cell devices. The assembled ZnO fuel cell demonstrates encouraging power outputs of 158–482 mW cm−2 and high open circuit voltages (OCVs) of 1–1.06 V at 450–550 °C, while the ZnO-LCP cell delivers significantly enhanced performance with maximum power density of 864 mW cm−2 and OCV of 1.07 V at 550 °C. The conductive properties of the materials are investigated. As a consequence, the ZnO electrolyte and ZnO-LCP composite exhibit extraordinary ionic conductivities of 0.09 and 0.156 S cm−1 at 550 °C, respectively, and the proton conductive behavior of ZnO is verified. Furthermore, performance enhancement of the ZnO-LCP cell is studied by electrochemical impedance spectroscopy (EIS), which is found to be as a result of the significantly reduced grain boundary and electrode polarization resistances. These findings indicate that ZnO is a highly promising alternative semiconducting-ionic membrane to replace the electrolyte materials for advanced LT-SOFCs, which in turn provides a new strategic pathway for the future development of electrolytes. PMID:29283395

Flexible thin-film battery based on graphene-oxide embedded in solid polymer electrolyte

NASA Astrophysics Data System (ADS)

Kammoun, M.; Berg, S.; Ardebili, H.

2015-10-01

Enhanced safety of flexible batteries is an imperative objective due to the intimate interaction of such devices with human organs such as flexible batteries that are integrated with touch-screens or embedded in clothing or space suits. In this study, the fabrication and testing of a high performance thin-film Li-ion battery (LIB) is reported that is both flexible and relatively safer compared to the conventional electrolyte based batteries. The concept is facilitated by the use of solid polymer nanocomposite electrolyte, specifically, composed of polyethylene oxide (PEO) matrix and 1 wt% graphene oxide (GO) nanosheets. The flexible LIB exhibits a high maximum operating voltage of 4.9 V, high capacity of 0.13 mA h cm-2 and an energy density of 4.8 mW h cm-3. The battery is encapsulated using a simple lamination method that is economical and scalable. The laminated battery shows robust mechanical flexibility over 6000 bending cycles and excellent electrochemical performance in both flat and bent configurations. Finite element analysis (FEA) of the LIB provides critical insights into the evolution of mechanical stresses during lamination and bending.Enhanced safety of flexible batteries is an imperative objective due to the intimate interaction of such devices with human organs such as flexible batteries that are integrated with touch-screens or embedded in clothing or space suits. In this study, the fabrication and testing of a high performance thin-film Li-ion battery (LIB) is reported that is both flexible and relatively safer compared to the conventional electrolyte based batteries. The concept is facilitated by the use of solid polymer nanocomposite electrolyte, specifically, composed of polyethylene oxide (PEO) matrix and 1 wt% graphene oxide (GO) nanosheets. The flexible LIB exhibits a high maximum operating voltage of 4.9 V, high capacity of 0.13 mA h cm-2 and an energy density of 4.8 mW h cm-3. The battery is encapsulated using a simple lamination method that is economical and scalable. The laminated battery shows robust mechanical flexibility over 6000 bending cycles and excellent electrochemical performance in both flat and bent configurations. Finite element analysis (FEA) of the LIB provides critical insights into the evolution of mechanical stresses during lamination and bending. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04339e

A Molecular Electronic Transducer based Low-Frequency Accelerometer with Electrolyte Droplet Sensing Body

NASA Astrophysics Data System (ADS)

Liang, Mengbing

"Sensor Decade" has been labeled on the first decade of the 21st century. Similar to the revolution of micro-computer in 1980s, sensor R&D developed rapidly during the past 20 years. Hard workings were mainly made to minimize the size of devices with optimal the performance. Efforts to develop the small size devices are mainly concentrated around Micro-electro-mechanical-system (MEMS) technology. MEMS accelerometers are widely published and used in consumer electronics, such as smart phones, gaming consoles, anti-shake camera and vibration detectors. This study represents liquid-state low frequency micro-accelerometer based on molecular electronic transducer (MET), in which inertial mass is not the only but also the conversion of mechanical movement to electric current signal is the main utilization of the ionic liquid. With silicon-based planar micro-fabrication, the device uses a sub-micron liter electrolyte droplet sealed in oil as the sensing body and a MET electrode arrangement which is the anode-cathode-cathode-anode (ACCA) in parallel as the read-out sensing part. In order to sensing the movement of ionic liquid, an imposed electric potential was applied between the anode and the cathode. The electrode reaction, I3-- + 2e-- ↔ 3I --, occurs around the cathode which is reverse at the anodes. Obviously, the current magnitude varies with the concentration of ionic liquid, which will be effected by the movement of liquid droplet as the inertial mass. With such structure, the promising performance of the MET device design is to achieve 10.8 V/G (G=9.81 m/s2) sensitivity at 20 Hz with the bandwidth from 1 Hz to 50 Hz, and a low noise floor of 100 microg/sqrt(Hz) at 20 Hz.

Ion conduction in crystalline superionic solids and its applications

NASA Astrophysics Data System (ADS)

Chandra, Angesh

2014-06-01

Superionic solids an area of multidisciplinary research activity, incorporates to study the physical, chemical and technological aspects of rapid ion movements within the bulk of the special class of ionic materials. It is an emerging area of materials science, as these solids show tremendous technological scopes to develop wide variety of solid state electrochemical devices such as batteries, fuel cells, supercapacitors, sensors, electrochromic displays (ECDs), memories, etc. These devices have wide range of applicabilities viz. power sources for IC microchips to transport vehicles, novel sensors for controlling atmospheric pollution, new kind of memories for computers, smart windows/display panels, etc. The field grew with a rapid pace since then, especially with regards to designing new materials as well as to explore their device potentialities. Amongst the known superionic solids, fast Ag+ ion conducting crystalline solid electrolytes are attracted special attention due to their relatively higher room temperature conductivity as well as ease of materials handling/synthesis. Ion conduction in these electrolytes is very much interesting part of today. In the present review article, the ion conducting phenomenon and some device applications of crystalline/polycrystalline superionic solid electrolytes have been reviewed in brief. Synthesis and characterization tools have also been discussed in the present review article.

Durable electrooptic devices comprising ionic liquids

DOEpatents

Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM; Burrell, Anthony K [Los Alamos, NM

2006-10-10

Electrolyte solutions for electrochromic devices such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes.

Advanced Proton Conducting Polymer Electrolytes for Electrochemical Capacitors

NASA Astrophysics Data System (ADS)

Gao, Han

Research on solid electrochemical energy storage devices aims to provide high performance, low cost, and safe operation solutions for emerging applications from flexible consumer electronics to microelectronics. Polymer electrolytes, minimizing device sealing and liquid electrolyte leakage, are key enablers for these next-generation technologies. In this thesis, a novel proton-conducing polymer electrolyte system has been developed using heteropolyacids (HPAs) and polyvinyl alcohol for electrochemical capacitors. A thorough understanding of proton conduction mechanisms of HPAs together with the interactions among HPAs, additives, and polymer framework has been developed. Structure and chemical bonding of the electrolytes have been studied extensively to identify and elucidate key attributes affecting the electrolyte properties. Numerical models describing the proton conduction mechanism have been applied to differentiate those attributes. The performance optimization of the polymer electrolytes through additives, polymer structural modifications, and synthesis of alternative HPAs has achieved several important milestones, including: (a) high proton mobility and proton density; (b) good ion accessibility at electrode/electrolyte interface; (c) wide electrochemical stability window; and (d) good environmental stability. Specifically, high proton mobility has been addressed by cross-linking the polymer framework to improve the water storage capability at normal-to-high humidity conditions (e.g. 50-80% RH) as well as by incorporating nano-fillers to enhance the water retention at normal humidity levels (e.g. 30-60% RH). High proton density has been reached by utilizing additional proton donors (i.e. acidic plasticizers) and by developing different HPAs. Good ion accessibility has been achieved through addition of plasticizers. Electrochemical stability window of the electrolyte system has also been investigated and expanded by utilizing HPAs with different heteroatoms. The optimized polymer electrolyte demonstrated even higher proton conductivity than pure HPAs and the enabled electrochemical capacitors have demonstrated an exceptionally high rate capability of 50 Vs-1 in cyclic voltammograms and a 10 ms time constant in impedance analyses.

Scalable Fabrication of Photochemically Reduced Graphene-Based Monolithic Micro-Supercapacitors with Superior Energy and Power Densities.

PubMed

Wang, Sen; Wu, Zhong-Shuai; Zheng, Shuanghao; Zhou, Feng; Sun, Chenglin; Cheng, Hui-Ming; Bao, Xinhe

2017-04-25

Micro-supercapacitors (MSCs) hold great promise as highly competitive miniaturized power sources satisfying the increased demand of smart integrated electronics. However, single-step scalable fabrication of MSCs with both high energy and power densities is still challenging. Here we demonstrate the scalable fabrication of graphene-based monolithic MSCs with diverse planar geometries and capable of superior integration by photochemical reduction of graphene oxide/TiO 2 nanoparticle hybrid films. The resulting MSCs exhibit high volumetric capacitance of 233.0 F cm -3 , exceptional flexibility, and remarkable capacity of modular serial and parallel integration in aqueous gel electrolyte. Furthermore, by precisely engineering the interface of electrode with electrolyte, these monolithic MSCs can operate well in a hydrophobic electrolyte of ionic liquid (3.0 V) at a high scan rate of 200 V s -1 , two orders of magnitude higher than those of conventional supercapacitors. More notably, the MSCs show landmark volumetric power density of 312 W cm -3 and energy density of 7.7 mWh cm -3 , both of which are among the highest values attained for carbon-based MSCs. Therefore, such monolithic MSC devices based on photochemically reduced, compact graphene films possess enormous potential for numerous miniaturized, flexible electronic applications.

Conductivity and Thermal Studies on Plasticized Nano-Composite Solid Polymer Electrolyte, Peo: Ec: LiTf: Al2O3

NASA Astrophysics Data System (ADS)

Pitawala, H. M. J. C.; Dissanayake, M. A. K. L.; Seneviratne, V. A.

2006-06-01

Poly (ethylene oxide)-(PEO)-based composite polymer electrolytes are of great interest for solid-state-electrochemical devices. This paper presents the results of a preliminary study on electrical conductivity and thermal behavior (DSC) of composite polymer electrolytes (CPEs) containing PEO: LiCF3SO3 complexed with plasticizer (EC) and incorporating nano-sized particles of the ceramic filler Al2O3. Ionic conductivity enhancement in these electrolytes has been obtained by optimizing the combined effect of the plasticizer and the ceramic filler. Nano-composite, plasticized polymer electrolyte films (400-600μm) were prepared by common solvent casting method. It was revealed that the presence of the Al2O3 filler in PEO: LiTf polymer electrolyte significantly enhanced the ionic conductivity in the temperature range of interest, giving the maximum conductivity for (PEO)9LiTf+15 wt.% Al2O3 CPE [σRT (max)=2×10-5 S cm-1]. It was also observed that the addition of plasticizer (EC) to this electrolyte up to a concentration of 50 wt. % EC, showed a further conductivity enhancement [σRT (max) = 1.5×10-4 S cm-1]. It is suggested that the conductivity is enhanced mainly by two mechanisms. The plasticizer (EC) would directly contribute by reducing the crystallinity and increasing the amorphous phase content of the polymer electrolytes. The ceramic filler (Al2O3) would contribute to conductivity enhancement by creating additional sites to migrating ionic species through transient bonding with O/OH groups in the filler surface. The decrease of Tg values of plasticized CPE systems seen in the DSC thermograms points towards the improved segmental flexibility of polymer chains, increasing the mobility of conducting ions.

Synthesis and characterization of nanocomposite polymer blend electrolyte thin films by spin-coating method

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

Chapi, Sharanappa; Niranjana, M.; Devendrappa, H., E-mail: dehu2010@gmail.com

2016-05-23

Solid Polymer blend electrolytes based on Polyethylene oxide (PEO) and poly vinyl pyrrolidone (PVP) complexed with zinc oxide nanoparticles (ZnO NPs; Synthesized by Co-precipitation method) thin films have prepared at a different weight percent using the spin-coating method. The complexation of the NPs with the polymer blend was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). The variation in film morphology was examined by polarized optical micrographs (POMs). The thermal behavior of blends was investigated under non-isothermal conditions by differential thermal analyses (DTA). A single glass transition temperature for each blend was observed, which supports the existence ofmore » compatibility of such system. The obtained results represent that the ternary based thin films are prominent materials for battery and optoelectronic device applications.« less

On-chip and freestanding elastic carbon films for micro-supercapacitors

DOE PAGES

Huang, Peihua; Lethien, C.; Pinaud, S.; ...

2016-02-11

Integration of electrochemical capacitors with silicon-based electronics is a major challenge, limiting energy storage on a chip. We describe a wafer-scale process for manufacturing strongly adhering carbide-derived carbon films and interdigitated micro-supercapacitors with embedded titanium carbide current collectors, fully compatible with current microfabrication and silicon-based device technology. Capacitance of those films reaches 410 farads per cubic centimeter/200 millifarads per square centimeter in aqueous electrolyte and 170 farads per cubic centimeter/85 millifarads per square centimeter in organic electrolyte. We also demonstrate preparation of self-supported, mechanically stable, micrometer-thick porous carbon films with a Young’s modulus of 14.5 gigapascals, with the possibility ofmore » further transfer onto flexible substrates. Lastly, these materials are interesting for applications in structural energy storage, tribology, and gas separation.« less

On-chip and freestanding elastic carbon films for micro-supercapacitors

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

Huang, Peihua; Lethien, C.; Pinaud, S.

Integration of electrochemical capacitors with silicon-based electronics is a major challenge, limiting energy storage on a chip. We describe a wafer-scale process for manufacturing strongly adhering carbide-derived carbon films and interdigitated micro-supercapacitors with embedded titanium carbide current collectors, fully compatible with current microfabrication and silicon-based device technology. Capacitance of those films reaches 410 farads per cubic centimeter/200 millifarads per square centimeter in aqueous electrolyte and 170 farads per cubic centimeter/85 millifarads per square centimeter in organic electrolyte. We also demonstrate preparation of self-supported, mechanically stable, micrometer-thick porous carbon films with a Young’s modulus of 14.5 gigapascals, with the possibility ofmore » further transfer onto flexible substrates. Lastly, these materials are interesting for applications in structural energy storage, tribology, and gas separation.« less

A novel coronene//Na2Ti3O7 dual-ion battery

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

Dong, Shengyang; Li, Zhifei; Rodríguez-Pérez, Isma

Here we construct a novel sodium dual-ion battery (Na-DIB) with a conventional alkyl/alkylene carbonate electrolyte by using reduced-graphene-oxide-coated Na2Ti3O7 (NTO@G) as the anode and coronene, a polycyclic aromatic hydrocarbon (PAH), as the cathode. The coronene//NTO@G configuration delivers a specific energy of 77 W h kg−1, based on the total active mass in both electrodes, and excellent cycling stability with 80% capacity retention after 5000 cycles. In addition, this device can work well in a wide range of temperatures from −20 to 40 °C. The results demonstrate a proof-of-concept Na-DIB that avoids the challenges of conventional dual-graphite DIBs by utilizing non-graphitemore » intercalation anode and cathode, and a carbonate-based electrolyte without any additives.« less

Electrolytes For Electrooptic Devices Comprising Ionic Liqu Ids

DOEpatents

Warner, Benjamin P.; McCleskey, T. Mark; Agrawal, Anoop; Cronin, John P.; Tonazzi, Juan C. L.; Burrell, Anthony K.

2005-02-08

Electrolyte solutions of soluble bifunctional redox dyes in molten salt solvent may be used to prepare electrooptic devices with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF.sub.3 SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3 SO.sub.2).sub.2 N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3 CF.sub.2 SO.sub.2).sub.2 N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3 SO.sub.2).sub.3 C.sup.-).

Electrolysis cell for the manufacture of persulfates

NASA Technical Reports Server (NTRS)

Cueto, J. M.

1986-01-01

A cell for the electrolytic generation of persulfates, characterized by the fact that a housing acts as cathode, is made of metal, and consists of a lower electrolytically active section and an upper electrolytically inactive section. It is designed so that there is produced the greatest possible current density suited to produce the desired electrolysis effect. This invention, compared to the devices used until now, exhibits considerable advantages whereby it is particularly suited for the production of potassium persulfate.

Floating gate transistors as biosensors (Conference Presentation)

NASA Astrophysics Data System (ADS)

Frisbie, C. Daniel

2016-11-01

Electrolyte gated transistors (EGTs) are a sub-class of thin film transistors that are extremely promising for biological sensing applications. These devices employ a solid electrolyte as the gate insulator; the very large capacitance of the electrolyte results in low voltage operation and high transconductance or gain. This talk will describe the fabrication of floating gate EGTs and their use as ricin sensors. The critical performance metrics for EGTs compared with other types of TFTs will also be reviewed.

Electrode stabilizing materials

DOEpatents

Amine, Khalil; Abouimrane, Ali; Moore, Jeffrey S.; Odom, Susan A.

2015-11-03

An electrolyte includes a polar aprotic solvent; an alkali metal salt; and an electrode stabilizing compound that is a monomer, which when polymerized forms an electrically conductive polymer. The electrode stabilizing compound is a thiophene, a imidazole, a anilines, a benzene, a azulene, a carbazole, or a thiol. Electrochemical devices may incorporate such electrolytes.

Solid electrolyte structure

DOEpatents

Fraioli, Anthony V.

1984-01-01

A solid electrolyte structure for fuel cells and other electrochemical devices providing oxygen ion transfer by a multiplicity of exposed internal surfaces made of a composition containing an oxide of a multivalent transition metal and forming small pore-like passages sized to permit oxygen ion transfer while limiting the transfer of oxygen gas.

Gas-Phase Functionalization of Macroscopic Carbon Nanotube Fiber Assemblies: Reaction Control, Electrochemical Properties, and Use for Flexible Supercapacitors.

PubMed

Iglesias, Daniel; Senokos, Evgeny; Alemán, Belén; Cabana, Laura; Navío, Cristina; Marcilla, Rebeca; Prato, Maurizio; Vilatela, Juan J; Marchesan, Silvia

2018-02-14

The assembly of aligned carbon nanotubes (CNTs) into fibers (CNTFs) is a convenient approach to exploit and apply the unique physico-chemical properties of CNTs in many fields. CNT functionalization has been extensively used for its implementation into composites and devices. However, CNTF functionalization is still in its infancy because of the challenges associated with preservation of CNTF morphology. Here, we report a thorough study of the gas-phase functionalization of CNTF assemblies using ozone which was generated in situ from a UV source. In contrast with liquid-based oxidation methods, this gas-phase approach preserves CNTF morphology, while notably increasing its hydrophilicity. The functionalized material is thoroughly characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy. Its newly acquired hydrophilicity enables CNTF electrochemical characterization in aqueous media, which was not possible for the pristine material. Through comparison of electrochemical measurements in aqueous electrolytes and ionic liquids, we decouple the effects of functionalization on pseudocapacitive reactions and quantum capacitance. The functionalized CNTF assembly is successfully used as an active material and a current collector in all-solid supercapacitor flexible devices with an ionic liquid-based polymer electrolyte.

Light-Addressed Electrodeposition of Enzyme-Entrapped Chitosan Membranes for Multiplexed Enzyme-Based Bioassays Using a Digital Micromirror Device

PubMed Central

Huang, Shih-Hao; Wei, Lu-Shiuan; Chu, Hsiao-Tzu; Jiang, Yeu-Long

2013-01-01

This paper describes a light-addressed electrolytic system used to perform an electrodeposition of enzyme-entrapped chitosan membranes for multiplexed enzyme-based bioassays using a digital micromirror device (DMD). In this system, a patterned light illumination is projected onto a photoconductive substrate serving as a photo-cathode to electrolytically produce hydroxide ions, which leads to an increased pH gradient. The high pH generated at the cathode can cause a local gelation of chitosan through sol-gel transition. By controlling the illumination pattern on the DMD, a light-addressed electrodeposition of chitosan membranes with different shapes and sizes, as well as multiplexed micropatterning, was performed. The effect of the illumination time of the light pattern on the dimensional resolution of chitosan membrane formation was examined experimentally. Moreover, multiplexed enzyme-based bioassay of enzyme-entrapped chitosan membranes was also successfully demonstrated through the electrodeposition of the chitosan membranes with various shapes/sizes and entrapping different enzymes. As a model experiment, glucose and ethanol were simultaneously detected in a single detection chamber without cross-talk using shape-coded chitosan membranes entrapped with glucose oxidase (GOX), peroxidase (POD), and Amplex Red (AmR) or alcohol oxidase (AOX), POD, and AmR by using same fluorescence indicator (AmR). PMID:23959236

Light-addressed electrodeposition of enzyme-entrapped chitosan membranes for multiplexed enzyme-based bioassays using a digital micromirror device.

PubMed

Huang, Shih-Hao; Wei, Lu-Shiuan; Chu, Hsiao-Tzu; Jiang, Yeu-Long

2013-08-16

This paper describes a light-addressed electrolytic system used to perform an electrodeposition of enzyme-entrapped chitosan membranes for multiplexed enzyme-based bioassays using a digital micromirror device (DMD). In this system, a patterned light illumination is projected onto a photoconductive substrate serving as a photo-cathode to electrolytically produce hydroxide ions, which leads to an increased pH gradient. The high pH generated at the cathode can cause a local gelation of chitosan through sol-gel transition. By controlling the illumination pattern on the DMD, a light-addressed electrodeposition of chitosan membranes with different shapes and sizes, as well as multiplexed micropatterning, was performed. The effect of the illumination time of the light pattern on the dimensional resolution of chitosan membrane formation was examined experimentally. Moreover, multiplexed enzyme-based bioassay of enzyme-entrapped chitosan membranes was also successfully demonstrated through the electrodeposition of the chitosan membranes with various shapes/sizes and entrapping different enzymes. As a model experiment, glucose and ethanol were simultaneously detected in a single detection chamber without cross-talk using shape-coded chitosan membranes entrapped with glucose oxidase (GOX), peroxidase (POD), and Amplex Red (AmR) or alcohol oxidase (AOX), POD, and AmR by using same fluorescence indicator (AmR).

Natural cellulose fiber as substrate for supercapacitor.

PubMed

Gui, Zhe; Zhu, Hongli; Gillette, Eleanor; Han, Xiaogang; Rubloff, Gary W; Hu, Liangbing; Lee, Sang Bok

2013-07-23

Cellulose fibers with porous structure and electrolyte absorption properties are considered to be a good potential substrate for the deposition of energy material for energy storage devices. Unlike traditional substrates, such as gold or stainless steel, paper prepared from cellulose fibers in this study not only functions as a substrate with large surface area but also acts as an interior electrolyte reservoir, where electrolyte can be absorbed much in the cellulose fibers and is ready to diffuse into an energy storage material. We demonstrated the value of this internal electrolyte reservoir by comparing a series of hierarchical hybrid supercapacitor electrodes based on homemade cellulose paper or polyester textile integrated with carbon nanotubes (CNTs) by simple solution dip and electrodeposited with MnO2. Atomic layer deposition of Al2O3 onto the fiber surface was used to limit electrolyte absorption into the fibers for comparison. Configurations designed with different numbers of ion diffusion pathways were compared to show that cellulose fibers in paper can act as a good interior electrolyte reservoir and provide an effective pathway for ion transport facilitation. Further optimization using an additional CNT coating resulted in an electrode of paper/CNTs/MnO2/CNTs, which has dual ion diffusion and electron transfer pathways and demonstrated superior supercapacitive performance. This paper highlights the merits of the mesoporous cellulose fibers as substrates for supercapacitor electrodes, in which the water-swelling effect of the cellulose fibers can absorb electrolyte, and the mesoporous internal structure of the fibers can provide channels for ions to diffuse to the electrochemical energy storage materials.

Li-Ion Cells Employing Electrolytes With Methyl Propionate and Ethyl Butyrate Co-Solvents

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Bugga, Ratnakumar V.

2011-01-01

Future NASA missions aimed at exploring Mars and the outer planets require rechargeable batteries that can operate at low temperatures to satisfy the requirements of such applications as landers, rovers, and penetrators. A number of terrestrial applications, such as hybrid electric vehicles (HEVs) and electric vehicles (EVs) also require energy storage devices that can operate over a wide temperature range (i.e., -40 to +70 C), while still providing high power capability and long life. Currently, the state-of-the-art lithium-ion system has been demonstrated to operate over a wide range of temperatures (-30 to +40 C); however, the rate capability at the lower temperatures is very poor. These limitations at very low temperatures are due to poor electrolyte conductivity, poor lithium intercalation kinetics over the electrode surface layers, and poor ionic diffusion in the electrode bulk. Two wide-operating-temperature-range electrolytes have been developed based on advances involving lithium hexafluorophosphate-based solutions in carbonate and carbonate + ester solvent blends, which have been further optimized in the context of the technology and targeted applications. The approaches employed include further optimization of electrolytes containing methyl propionate (MP) and ethyl butyrate (EB), which are effective co-solvents, to widen the operating temperature range beyond the baseline systems. Attention was focused on further optimizing ester-based electrolyte formulations that have exhibited the best performance at temperatures ranging from -60 to +60 C, with an emphasis upon improving the rate capability at -20 to -40 C. This was accomplished by increasing electrolyte salt concentration to 1.20M and increasing the ester content to 60 percent by volume to increase the ionic conductivity at low temperatures. Two JPL-developed electrolytes 1.20M LiPF6 in EC+EMC+MP (20:20:60 v/v %) and 1.20M LiPF6 in EC+EMC+EB (20:20:60 v/v %) operate effectively over a wide temperature range in MCMB-LiNiCoAlO2 and Li4Ti5O12-LiNi-CoAlO2 prototype cells. These electrolytes have enabled high rate performance at low temperature (i.e., up to 2.0C rates at -50 C and 5.0C rates at -40 C), and good cycling performance over a wide temperature range (i.e., from -40 to +70 C). Current efforts are focused upon improving the high temperature resilience of the methyl propionatebased system through the use of electrolyte additives, which are envisioned to improve the nature of the solid electrolyte interphase (SEI) layers.

Nanogranular SiO2 proton gated silicon layer transistor mimicking biological synapses

NASA Astrophysics Data System (ADS)

Liu, M. J.; Huang, G. S.; Feng, P.; Guo, Q. L.; Shao, F.; Tian, Z. A.; Li, G. J.; Wan, Q.; Mei, Y. F.

2016-06-01

Silicon on insulator (SOI)-based transistors gated by nanogranular SiO2 proton conducting electrolytes were fabricated to mimic synapse behaviors. This SOI-based device has both top proton gate and bottom buried oxide gate. Electrical transfer properties of top proton gate show hysteresis curves different from those of bottom gate, and therefore, excitatory post-synaptic current and paired pulse facilitation (PPF) behavior of biological synapses are mimicked. Moreover, we noticed that PPF index can be effectively tuned by the spike interval applied on the top proton gate. Synaptic behaviors and functions, like short-term memory, and its properties are also experimentally demonstrated in our device. Such SOI-based electronic synapses are promising for building neuromorphic systems.

Establishment of a biomimetic device based on tri-layer polymer actuators--propulsion fins.

PubMed

Alici, Gursel; Spinks, Geoffrey; Huynh, Nam N; Sarmadi, Laleh; Minato, Rick

2007-06-01

We propose to use bending type tri-layer polymer actuators as propulsion fins for a biomimetic device consisting of a rigid body, like a box fish having a carapace, and paired fins running through the rigid body, like a fish having pectoral fins. The fins or polymer bending actuators can be considered as individually controlled flexible membranes. Each fin is activated with sinusoidal inputs such that there is a phase lag between the movements of successive fins to create enough thrust force for propulsion. Eight fins with 0.125 aspect ratio have been used along both sides of the rigid body to move the device in the direction perpendicular to the longitudinal axis of the body. The designed device with the paired fins was successfully tested, moving in an organic solution consisting of solvent, propylene carbonate (PC), and electrolyte. The design procedure outlined in this study is offered as a guide to making functional devices based on polymer actuators and sensors.

The role of ultra-thin SiO2 layers in metal-insulator-semiconductor (MIS) photoelectrochemical devices (Presentation Recording)

NASA Astrophysics Data System (ADS)

Esposito, Daniel V.

2015-08-01

Solid-state junctions based on a metal-insulator-semiconductor (MIS) architecture are of great interest for a number of optoelectronic applications such as photovoltaics, photoelectrochemical cells, and photodetection. One major advantage of the MIS junction compared to the closely related metal-semiconductor junction, or Schottky junction, is that the thin insulating layer (1-3 nm thick) that separates the metal and semiconductor can significantly reduce the density of undesirable interfacial mid-gap states. The reduction in mid-gap states helps "un-pin" the junction, allowing for significantly higher built-in-voltages to be achieved. A second major advantage of the MIS junction is that the thin insulating layer can also protect the underlying semiconductor from corrosion in an electrochemical environment, making the MIS architecture well-suited for application in (photo)electrochemical applications. In this presentation, discontinuous Si-based MIS junctions immersed in electrolyte are explored for use as i.) photoelectrodes for solar-water splitting in photoelectrochemical cells (PECs) and ii.) position-sensitive photodetectors. The development and optimization of MIS photoelectrodes for both of these applications relies heavily on understanding how processing of the thin SiO2 layer impacts the properties of nano- and micro-scale MIS junctions, as well as the interactions of the insulating layer with the electrolyte. In this work, we systematically explore the effects of insulator thickness, synthesis method, and chemical treatment on the photoelectrochemical and electrochemical properties of these MIS devices. It is shown that electrolyte-induced inversion plays a critical role in determining the charge carrier dynamics within the MIS photoelectrodes for both applications.

Methods for dispensing mercury into devices

DOEpatents

Grossman, M.W.; George, W.A.

1987-04-28

A process is described for dispensing mercury into devices which requires mercury. Mercury is first electrolytically separated from either HgO or Hg[sub 2]Cl[sub 2] and plated onto a cathode wire. The cathode wire is then placed into a device requiring mercury. 2 figs.

Conducting Polymeric Hydrogel Electrolyte Based on Carboxymethylcellulose and Polyacrylamide/Polyaniline for Supercapacitor Applications

NASA Astrophysics Data System (ADS)

Suganya, N.; Jaisankar, V.; Sivakumar, E. K. T.

Conducting polymer hydrogels represent a unique class of materials that possess enormous application in flexible electronic devices. In the present work, conducting carboxymethylcellulose (CMC)-co-polyacrylamide (PAAm)/polyaniline was synthesized by a two-step interpenetrating network solution polymerization technique. The synthesized CMC-co-PAAm/polyaniline with interpenetrating network structure was prepared by in situ polymerization of aniline to enhance conductivity. The molecular structure and morphology of the copolymer hydrogels were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The novel conducting polymer hydrogels show good electrical and electrochemical behavior, which makes them potentially useful in electronic devices such as supercapacitors, biosensors, bioelectronics, solar cells and memory devices.

Micro-supercapacitors from carbide derived carbon (CDC) films on silicon chips

NASA Astrophysics Data System (ADS)

Huang, Peihua; Heon, Min; Pech, David; Brunet, Magali; Taberna, Pierre-Louis; Gogotsi, Yury; Lofland, Samuel; Hettinger, Jeffrey D.; Simon, Patrice

2013-03-01

Interdigitated on-chip micro-supercapacitors based on Carbide Derived Carbon (CDC) films were fabricated and tested. A titanium carbide (TiC) film was patterned and treated with chlorine to obtain a TiC derived carbon (TiC-CDC) film, followed by the deposition of two types of current collectors (Ti/Au and Al) using standard micro-fabrication processes. CDC based micro-supercapacitors were electrochemically characterized by cyclic voltammetry and impedance spectroscopy using a 1 M tetraethylammonium tetrafluoroborate, NEt4BF4, in propylene carbonate (PC) electrolyte. A capacitance of 0.78 mF for the device and 1.5 mF cm-2 as the specific capacitance for the footprint of the device was measured for a 2 V potential range at 100 mV s-1. A specific energy of 3.0 mJ cm-2 and a specific power of 84 mW cm-2 were calculated for the devices. These devices provide a pathway for fabricating pure carbon-based micro-supercapacitors by micro-fabrication, and can be used for powering micro-electromechanical systems (MEMS) and electronic devices.

Fabrication and Performance of Zirconia Electrolysis Cells for Cabon Dioxide Reduction for Mars In Situ Resource Utilization Applications

NASA Technical Reports Server (NTRS)

Minh, N. Q.; Chung, B. W.; Doshi, R.; Lear, G. R.; Montgomery, K.; Ong, E. T.

1999-01-01

Use of the Martian atmosphere (95% CO2) to produce oxygen (for propellant and life support) can significantly lower the required launch mass and dramatically reduce the total cost for Mars missions. Zirconia electrolysis cells are one of the technologies being considered for oxygen generation from carbon dioxide in Mars In Situ Resource Utilization (ISRU) production plants. The attractive features of the zirconia cell for this application include simple operation and lightweight, low volume system. A zirconia electrolysis cell is an all-solid state device, based on oxygen-ion conducting zirconia electrolytes, that electrochemically reduces carbon dioxide to oxygen and carbon monoxide. The cell consists of two porous electrodes (the anode and cathode) separated by a dense zirconia electrolyte. Typical zirconia cells contain an electrolyte layer which is 200 to 400 micrometer thick. The electrical conductivity requirement for the electrolyte necessitates an operating temperature of 9000 to 10000C. Recently, the fabrication of zirconia cells by the tape calendering has been evaluated. This fabrication process provides a simple means of making cells having very thin electrolytes (5 to 30 micrometers). Thin zirconia electrolytes reduce cell ohmic losses, permitting efficient operation at lower temperatures (8000C or below). Thus, tape-calendered cells provides not only the potential of low temperature operation but also the flexibility in operating temperatures. This paper describes the fabrication of zirconia cells by the tape calendering method and discusses the performance results obtained to date.

[4,4‧-bi(1,3,2-dioxathiolane)] 2,2‧-dioxide: A novel cathode additive for high-voltage performance in lithium ion batteries

NASA Astrophysics Data System (ADS)

Lee, Sang Hyun; Yoon, Sukeun; Hwang, Eui-Hyung; Kwon, Young-Gil; Lee, Young-Gi; Cho, Kuk Young

2018-02-01

High-voltage operation of lithium-ion batteries (LIBs) is a facile approach to obtaining high specific energy density, especially for LiNi0·5Mn0·3Co0·2O2 (NMC532) cathodes currently used in mid- and large-sized energy storage devices. However, high-voltage charging (>4.3 V) is accompanied by a rapid capacity fade over long cycles due to severe continuous electrolyte decomposition and instability at the cathode surface. In this study, the sulfite-based compound, [4,4‧-bi(1,3,2-dioxathiolane)] 2,2‧-dioxide (BDTD) is introduced as a novel electrolyte additive to enhance electrochemical performances of alumina-coated NMC532 cathodes cycled in the voltage range of 3.0-4.6 V. X-ray photoelectron spectroscopy (XPS) and AC impedance of cells reveal that BDTD preferentially oxidizes prior to the electrolyte solvents and forms stable film layers on to the cathode surface, preventing increased impedance caused by repeated electrolyte solvent decomposition in high-voltage operation. The cycling performance of the Li/NMC532 half-cell using an electrolyte of 1.0 M LiPF6 in ethylene carbonate/ethyl methyl carbonate (3/7, in volume) can be improved by adding a small amount of BDTD into the electrolyte. BDTD enables the usage of sulfite-type additives for cathodes in high-voltage operation.

Electrochemical behavior of high performance on-chip porous carbon films for micro-supercapacitors applications in organic electrolytes

NASA Astrophysics Data System (ADS)

Brousse, K.; Huang, P.; Pinaud, S.; Respaud, M.; Daffos, B.; Chaudret, B.; Lethien, C.; Taberna, P. L.; Simon, P.

2016-10-01

Carbide derived carbons (CDCs) are promising materials for preparing integrated micro-supercapacitors, as on-chip CDC films are prepared via a process fully compatible with current silicon-based device technology. These films show good adherence on the substrate and high capacitance thanks to their unique nanoporous structure which can be fine-tuned by adjusting the synthesis parameters during chlorination of the metallic carbide precursor. The carbon porosity is mostly related to the synthesis temperature whereas the thickness of the films depends on the chlorination duration. Increasing the pore size allows the adsorption of large solvated ions from organic electrolytes and leads to higher energy densities. Here, we investigated the electrochemical behavior and performance of on-chip TiC-CDC in ionic liquid solvent mixtures of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) diluted in either acetonitrile or propylene carbonate via cyclic voltammetry and electrochemical impedance spectroscopy. Thin CDC films exhibited typical capacitive signature and achieved 169 F cm-3 in both electrolytes; 65% of the capacitance was still delivered at 1 V s-1. While increasing the thickness of the films, EMI+ transport limitation was observed in more viscous PC-based electrolyte. Nevertheless, the energy density reached 90 μW h cm-2 in 2M EMIBF4/ACN, confirming the interest of these CDC films for micro-supercapacitors applications.

Flexible solid-state supercapacitors based on carbon nanoparticles/MnO2 nanorods hybrid structure.

PubMed

Yuan, Longyan; Lu, Xi-Hong; Xiao, Xu; Zhai, Teng; Dai, Junjie; Zhang, Fengchao; Hu, Bin; Wang, Xue; Gong, Li; Chen, Jian; Hu, Chenguo; Tong, Yexiang; Zhou, Jun; Wang, Zhong Lin

2012-01-24

A highly flexible solid-state supercapacitor was fabricated through a simple flame synthesis method and electrochemical deposition process based on a carbon nanoparticles/MnO(2) nanorods hybrid structure using polyvinyl alcohol/H(3)PO(4) electrolyte. Carbon fabric is used as a current collector and electrode (mechanical support), leading to a simplified, highly flexible, and lightweight architecture. The device exhibited good electrochemical performance with an energy density of 4.8 Wh/kg at a power density of 14 kW/kg, and a demonstration of a practical device is also presented, highlighting the path for its enormous potential in energy management. © 2011 American Chemical Society

Scattering-layer-induced energy storage function in polymer-based quasi-solid-state dye-sensitized solar cells.

PubMed

Zhang, Xi; Jiang, Hongrui

2015-03-09

Photo-self-charging cells (PSCs) are compact devices with dual functions of photoelectric conversion and energy storage. By introducing a scattering layer in polymer-based quasi-solid-state dye-sensitized solar cells, two-electrode PSCs with highly compact structure were obtained. The charge storage function stems from the formed ion channel network in the scattering layer/polymer electrolyte system. Both the photoelectric conversion and the energy storage functions are integrated in only the photoelectrode of such PSCs. This design of PSC could continuously output power as a solar cell with considerable efficiency after being photo-charged. Such PSCs could be applied in highly-compact mini power devices.

Electrolyte for stable cycling of high-energy lithium sulfur redox flow batteries

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

Xiao, Jie; Liu, Jun; Pan, Huilin

A device comprising: a lithium sulfur redox flow battery comprising an electrolyte composition comprising: (i) a dissolved Li 2S x electroactive salt, wherein x.gtoreq.4; (ii) a solvent selected from dimethyl sulfoxide, tetrahydrofuran, or a mixture thereof; and (iii) a supporting salt at a concentration of at least 2 M, as measured by moles of supporting salt divided by the volume of the solvent without considering the volume change of the electrolyte after dissolving the supporting salt.

Lithium ion intercalation in thin crystals of hexagonal TaSe2 gated by a polymer electrolyte

NASA Astrophysics Data System (ADS)

Wu, Yueshen; Lian, Hailong; He, Jiaming; Liu, Jinyu; Wang, Shun; Xing, Hui; Mao, Zhiqiang; Liu, Ying

2018-01-01

Ionic liquid gating has been used to modify the properties of layered transition metal dichalcogenides (TMDCs), including two-dimensional (2D) crystals of TMDCs used extensively recently in the device work, which has led to observations of properties not seen in the bulk. The main effect comes from the electrostatic gating due to the strong electric field at the interface. In addition, ionic liquid gating also leads to ion intercalation when the ion size of the gate electrolyte is small compared to the interlayer spacing of TMDCs. However, the microscopic processes of ion intercalation have rarely been explored in layered TMDCs. Here, we employed a technique combining photolithography device fabrication and electrical transport measurements on the thin crystals of hexagonal TaSe2 using multiple channel devices gated by a polymer electrolyte LiClO4/Polyethylene oxide (PEO). The gate voltage and time dependent source-drain resistances of these thin crystals were used to obtain information on the intercalation process, the effect of ion intercalation, and the correlation between the ion occupation of allowed interstitial sites and the device characteristics. We found a gate voltage controlled modulation of the charge density waves and a scattering rate of charge carriers. Our work suggests that ion intercalation can be a useful tool for layered materials engineering and 2D crystal device design.

Iodine/iodide-free dye-sensitized solar cells.

PubMed

Yanagida, Shozo; Yu, Youhai; Manseki, Kazuhiro

2009-11-17

Dye-sensitized solar cells (DSSCs) are built from nanocrystalline anatase TiO(2) with a 101 crystal face (nc-TiO(2)) onto which a dye is absorbed, ruthenium complex sensitizers, fluid I(-)/I(3)(-) redox couples with electrolytes, and a Pt-coated counter electrode. DSSCs have now reached efficiencies as high as 11%, and G24 Innovation (Cardiff, U.K.) is currently manufacturing them for commercial use. These devices offer several distinct advantages. On the basis of the electron lifetime and diffusion coefficient in the nc-TiO(2) layer, DSSCs maintain a diffusion length on the order of several micrometers when the dyed-nc-TiO(2) porous layer is covered by redox electrolytes of lithium and/or imidazolium iodide and their polyiodide salts. The fluid iodide/iodine (I(-)/I(3)(-)) redox electrolytes can infiltrate deep inside the intertwined nc-TiO(2) layers, promoting the mobility of the nc-TiO(2) layers and serving as a hole-transport material of DSSCs. As a result, these materials eventually give a respectable photovoltaic performance. On the other hand, fluid I(-)/I(3)(-) redox shuttles have certain disadvantages: reduced performance control and long-term stability and incompatibility with some metallic component materials. The I(-)/I(3)(-) redox shuttle shows a significant loss in short circuit current density and a slight loss in open circuit voltage, particularly in highly viscous electrolyte-based DSSC systems. Iodine can also act as an oxidizing agent, corroding metals, such as the grid metal Ag and the Pt mediator on the cathode, especially in the presence of water and oxygen. In addition, the electrolytes (I(-)/I(3)(-)) can absorb visible light (lambda = approximately 430 nm), leading to photocurrent loss in the DSSC. Therefore, the introduction of iodide/iodine-free electrolytes or hole-transport materials (HTMs) could lead to cost-effective alternatives to TiO(2) DSSCs. In this Account, we discuss the iodide/iodine-free redox couple as a substitute for the fluid I(-)/I(3)(-) redox shuttle. We also review the adaptation of solid-state HTMs to the iodide/iodine-free solid-state DSSCs with an emphasis on their pore filling and charge mobility in devices and the relationship of those values to the performance of the resulting iodide/iodine-free DSSCs. We demonstrate how the structures of the sensitizing dye molecules and additives of lithium or imidazolium salts influence device performance. In addition, the self-organizing molecular interaction for electronic contact of HTMs to dye molecules plays an important role in unidirectional charge diffusion at interfaces. The poly(3,4-ethylenedioxythiophene) (PEDOT)-based DSSCs, which we obtain through photoelectrochemical polymerization (PEP) using 3-alkylthiophen-bearing ruthenium dye, HRS-1, and bis-EDOT, demonstrates the importance of nonbonding interface contact (e.g., pi-pi-stacking) for the successful inclusion of HTMs.

All-solid-state lithium organic battery with composite polymer electrolyte and pillar[5]quinone cathode.

PubMed

Zhu, Zhiqiang; Hong, Meiling; Guo, Dongsheng; Shi, Jifu; Tao, Zhanliang; Chen, Jun

2014-11-26

The cathode capacity of common lithium ion batteries (LIBs) using inorganic electrodes and liquid electrolytes must be further improved. Alternatively, all-solid-state lithium batteries comprising the electrode of organic compounds can offer much higher capacity. Herein, we successfully fabricated an all-solid-state lithium battery based on organic pillar[5]quinone (C35H20O10) cathode and composite polymer electrolyte (CPE). The poly(methacrylate) (PMA)/poly(ethylene glycol) (PEG)-LiClO4-3 wt % SiO2 CPE has an optimum ionic conductivity of 0.26 mS cm(-1) at room temperature. Furthermore, pillar[5]quinine cathode in all-solid-state battery rendered an average operation voltage of ∼2.6 V and a high initial capacity of 418 mAh g(-1) with a stable cyclability (94.7% capacity retention after 50 cycles at 0.2C rate) through the reversible redox reactions of enolate/quinonid carbonyl groups, showing favorable prospect for the device application with high capacity.

High-performance transistors for bioelectronics through tuning of channel thickness

PubMed Central

Rivnay, Jonathan; Leleux, Pierre; Ferro, Marc; Sessolo, Michele; Williamson, Adam; Koutsouras, Dimitrios A.; Khodagholy, Dion; Ramuz, Marc; Strakosas, Xenofon; Owens, Roisin M.; Benar, Christian; Badier, Jean-Michel; Bernard, Christophe; Malliaras, George G.

2015-01-01

Despite recent interest in organic electrochemical transistors (OECTs), sparked by their straightforward fabrication and high performance, the fundamental mechanism behind their operation remains largely unexplored. OECTs use an electrolyte in direct contact with a polymer channel as part of their device structure. Hence, they offer facile integration with biological milieux and are currently used as amplifying transducers for bioelectronics. Ion exchange between electrolyte and channel is believed to take place in OECTs, although the extent of this process and its impact on device characteristics are still unknown. We show that the uptake of ions from an electrolyte into a film of poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) leads to a purely volumetric capacitance of 39 F/cm3. This results in a dependence of the transconductance on channel thickness, a new degree of freedom that we exploit to demonstrate high-quality recordings of human brain rhythms. Our results bring to the forefront a transistor class in which performance can be tuned independently of device footprint and provide guidelines for the design of materials that will lead to state-of-the-art transistor performance. PMID:26601178

BIPV-Powered Smart Windows Utilizing Photovoltaic and Electrochromic Devices

PubMed Central

Ma, Rong-Hua; Chen, Yu-Chia

2012-01-01

A BIPV-powered smart window comprising a building-integrated photovoltaic (BIPV) panel and an all-solid-state electrochromic (EC) stack is proposed. In the proposed device, the output voltage of the BIPV panel varies in accordance with the intensity of the incident light and is modulated in such a way as to generate the EC stack voltage required to maintain the indoor illuminance within a specified range. Two different EC stacks are fabricated and characterized, namely one stack comprising ITO/WO3/Ta2O5/ITO and one stack comprising ITO/WO3/lithium-polymer electrolyte/ITO. It is shown that of the two stacks, the ITO/WO3/lithium-polymer electrolyte/ITO stack has a larger absorptance (i.e., approximately 99% at a driving voltage of 3.5 V). The experimental results show that the smart window incorporating an ITO/WO3/lithium-polymer electrolyte/ITO stack with an electrolyte thickness of 1.0 μm provides an indoor illuminance range of 750–1,500 Lux under typical summertime conditions in Taiwan. PMID:22368474

Improved Performance of Ionic Liquid Supercapacitors by using Tetracyanoborate Anions

PubMed Central

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

2018-01-01

Abstract Supercapacitors are energy storage devices designed to operate at higher power densities than conventional batteries, but their energy density is still too low for many applications. Efforts are made to design new electrolytes with wider electrochemical windows than aqueous or conventional organic electrolytes in order to increase energy density. Ionic liquids (ILs) with wide electrochemical stability windows are excellent candidates to be employed as supercapacitor electrolytes. ILs containing tetracyanoborate anions [B(CN)4] offer wider electrochemical stability than conventional electrolytes and maintain a high ionic conductivity (6.9 mS cm−1). Herein, we report the use of ILs containing the [B(CN)4] anion for such an application. They presented a high maximum operating voltage of 3.7 V, and two‐electrode devices demonstrate high specific capacitances even when operating at relatively high rates (ca. 20 F g−1 @ 15 A g−1). This supercapacitor stored more energy and operated at a higher power at all rates studied when compared with cells using a commonly studied ILs. PMID:29577008

A lithium ion battery using an aqueous electrolyte solution

PubMed Central

Chang, Zheng; Li, Chunyang; Wang, Yanfang; Chen, Bingwei; Fu, Lijun; Zhu, Yusong; Zhang, Lixin; Wu, Yuping; Huang, Wei

2016-01-01

Energy and environmental pollution have become the two major problems in today’s society. The development of green energy storage devices with good safety, high reliability, high energy density and low cost are urgently demanded. Here we report on a lithium ion battery using an aqueous electrolyte solution. It is built up by using graphite coated with gel polymer membrane and LISICON as the negative electrode, and LiFePO4 in aqueous solution as the positive electrode. Its average discharge voltage is up to 3.1 V and energy density based on the two electrode materials is 258 Wh kg−1. It will be a promising energy storage system with good safety and efficient cooling effects. PMID:27328707

Printable organic and inorganic materials for flexible electrochemical devices

NASA Astrophysics Data System (ADS)

Wojcik, Pawel Jerzy

The growing demand of consumer printed electronics such as smart cards, smart packaging, automotive displays, electronic paper and others led to the increased interest in fully printed electrochemical devices. These components are expected to be developed based on printed thin films derived from cheap and widely accessible compounds. This dissertation presents the long stretch of technical research that was performed to realize printed energy efficient concepts such as electrochromic displays and smart-windows. Within this broad theme, the presented study had a number of specific objectives, however, the overall aim was to develop low-cost material systems (i.e. printable mixtures) at a lab-scale, which would be compatible with large-scale roll-to-roll processing. Presented results concern three main topics: (i) dual-phase inorganic electrochromic material processed at low temperature, (ii) enhancement in electrochromic performance via metaloxide nanoparticles engineering, and (iii) highly conductive and mechanically stable solid-state electrolyte. First two topics are related to crystallographic structure of metal-oxide films derived from sol-gel precursor, which is shown to be critical for electrochemical performance. The proposed method of microstructure control enables development of electrochromic films which outperform their amorphous or nanocrystalline analogues presented in the state-of-the-art due to their superior chemical and physical properties. Developed materials and processes resulted in electrochemical devices exhibiting optical density on the level of 0.82 and switching time shorter than 3 seconds, reaching performance at practical level. Third topic concerns a new concept of solid state electrolyte based on plastic crystal doped with lithium salt, dispersed in a thermosetting polymer resin network. This soft matter printable electrolyte meets requirements for electrochromic applications, exhibiting ionic conductivities of 10. -6 - 10. -4 S cm-1 at ambient temperature, Young'sModulus in the range of 0.1 - 1.4 MPa and operational temperature up to 115°C. In order to extract information from massive computational data, model developed material systems and optimize composition, an efficient mathematical methodology based on statistical techniques was applied. This approach significantly reduces the number of experiments to be realized, while maintaining a high accuracy of the analysis. Using this approach the number of experiments has been reduced from 162 down to 30 in case of dual-phase electrochromic films, and from 729 down to 28 in study on solid-state electrolyte (when comparing to classical three-level full factorial approach). Coupling of statistical methods with formulation of electrochemically active materials shows the potential to maximize the capabilities of these systems.

Method for synthesis of titanium dioxide nanotubes using ionic liquids

DOEpatents

Qu, Jun; Luo, Huimin; Dai, Sheng

2013-11-19

The invention is directed to a method for producing titanium dioxide nanotubes, the method comprising anodizing titanium metal in contact with an electrolytic medium containing an ionic liquid. The invention is also directed to the resulting titanium dioxide nanotubes, as well as devices incorporating the nanotubes, such as photovoltaic devices, hydrogen generation devices, and hydrogen detection devices.

A passive microfluidic hydrogen-air fuel cell with exceptional stability and high performance.

PubMed

Mitrovski, Svetlana M; Nuzzo, Ralph G

2006-03-01

We describe an advanced microfluidic hydrogen-air fuel cell (FC) that exhibits exceptional durability and high performance, most notably yielding stable output power (>100 days) without the use of an anode-cathode separator membrane. This FC embraces an entirely passive device architecture and, unlike conventional microfluidic designs that exploit laminar hydrodynamics, no external pumps are used to sustain or localize the reagent flow fields. The devices incorporate high surface area/porous metal and metal alloy electrodes that are embedded and fully immersed in liquid electrolyte confined in the channels of a poly(dimethylsiloxane) (PDMS)-based microfluidic network. The polymeric network also serves as a self-supporting membrane through which oxygen and hydrogen are supplied to the cathode and alloy anode, respectively, by permeation. The operational stability of the device and its performance is strongly dependent on the nature of the electrolyte used (5 M H2SO4 or 2.5 M NaOH) and composition of the anode material. The latter choice is optimized to decrease the sensitivity of the system to oxygen cross-over while still maintaining high activity towards the hydrogen oxidation reaction (HOR). Three types of high surface area anodes were tested in this work. These include: high-surface area electrodeposited Pt (Pt); high-surface area electrodeposited Pd (Pd); and thin palladium adlayers supported on a "porous" Pt electrode (Pd/Pt). The FCs display their best performance in 5 M H2SO4 using the Pd/Pt anode. This exceptional stability and performance was ascribed to several factors, namely: the high permeabilities of O2, H2, and CO2 in PDMS; the inhibition of the formation of insoluble carbonate species due to the presence of a highly acidic electrolyte; and the selectivity of the Pd/Pt anode toward the HOR. The stability of the device for long-term operation was modeled using a stack of three FCs as a power supply for a portable display that otherwise uses a 3 V battery.

Towards Versatile and Sustainable Hydrogen Production through Electrocatalytic Water Splitting: Electrolyte Engineering

PubMed Central

Shinagawa, Tatsuya

2017-01-01

Abstract Recent advances in power generation from renewable resources necessitate conversion of electricity to chemicals and fuels in an efficient manner. Electrocatalytic water splitting is one of the most powerful and widespread technologies. The development of highly efficient, inexpensive, flexible, and versatile water electrolysis devices is desired. This review discusses the significance and impact of the electrolyte on electrocatalytic performance. Depending on the circumstances under which the water splitting reaction is conducted, the required solution conditions, such as the identity and molarity of ions, may significantly differ. Quantitative understanding of such electrolyte properties on electrolysis performance is effective to facilitate the development of efficient electrocatalytic systems. The electrolyte can directly participate in reaction schemes (kinetics), affect electrode stability, and/or indirectly impact the performance by influencing the concentration overpotential (mass transport). This review aims to guide fine‐tuning of the electrolyte properties, or electrolyte engineering, for (photo)electrochemical water splitting reactions. PMID:27984671

A rationally designed self-standing V2O5 electrode for high voltage non-aqueous all-solid-state symmetric (2.0 V) and asymmetric (2.8 V) supercapacitors.

PubMed

Ghosh, Meena; Vijayakumar, Vidyanand; Soni, Roby; Kurungot, Sreekumar

2018-05-10

The maximum capacitive potential window of certain pseudocapacitive materials cannot be accessed in aqueous electrolytes owing to the low dissociation potential of 1.2 V possessed by water molecules. However, the inferior pseudocapacitance exhibited by the commonly used electrode materials when integrated with non-aqueous electrolytes still remains a challenge in the development of supercapacitors (SC). Proper selection of materials for the electrode and a rational design process are indeed important to overcome these practical intricacies so that such systems can perform well with non-aqueous electrolytes. We address this challenge by fabricating a prototype all-solid-state device designed with high-capacitive V2O5 as the electrode material along with a Li-ion conducting organic electrolyte. V2O5 is synthesized on a pre-treated carbon-fibre paper by adopting an electrochemical deposition technique that effects an improved contact resistance. A judicious electrode preparation strategy makes it possible to overcome the constraints of the low ionic and electrical conductivities imposed by the electrolyte and electrode material, respectively. The device, assembled in a symmetrical fashion, achieves a high specific capacitance of 406 F g-1 (at 1 A g-1). The profitable aspect of using an organic electrolyte is also demonstrated with an asymmetric configuration by using activated carbon as the positive and V2O5 as the negative electrode materials, respectively. The asymmetric device displays a wide working-voltage window of 2.8 V and delivers a high energy density of 102.68 W h kg-1 at a power density of 1.49 kW kg-1. Moreover, the low equivalent series resistance of 9.9 Ω and negligible charge transfer resistance are observed in the impedance spectra, which is a key factor that accounts for such an exemplary performance.

Highly flexible and all-solid-state paperlike polymer supercapacitors.

PubMed

Meng, Chuizhou; Liu, Changhong; Chen, Luzhuo; Hu, Chunhua; Fan, Shoushan

2010-10-13

In recent years, much effort have been dedicated to achieve thin, lightweight and even flexible energy-storage devices for wearable electronics. Here we demonstrate a novel kind of ultrathin all-solid-state supercapacitor configuration with an extremely simple process using two slightly separated polyaniline-based electrodes well solidified in the H(2)SO(4)-polyvinyl alcohol gel electrolyte. The thickness of the entire device is much comparable to that of a piece of commercial standard A4 print paper. Under its highly flexible (twisting) state, the integrate device shows a high specific capacitance of 350 F/g for the electrode materials, well cycle stability after 1000 cycles and a leakage current of as small as 17.2 μA. Furthermore, due to its polymer-based component structure, it has a specific capacitance of as high as 31.4 F/g for the entire device, which is more than 6 times that of current high-level commercial supercapacitor products. These highly flexible and all-solid-state paperlike polymer supercapacitors may bring new design opportunities of device configuration for energy-storage devices in the future wearable electronic area.

Conductivity detection for monitoring mixing reactions in microfluidic devices.

PubMed

Liu, Y; Wipf, D O; Henry, C S

2001-08-01

A conductivity detector was coupled to poly(dimethylsiloxane)-glass capillary electrophoresis microchips to monitor microfluidic flow. Electroosmotic flow was investigated with both conductivity detection (CD) and the current monitoring method. No significant variation was observed between these methods, but CD showed a lower relative standard deviation. Gradient mixing experiments were employed to investigate the relationship between the electrolyte conductivity and the electrolyte concentration. A good linear response of conductivity to concentration was obtained for solutions whose difference in concentrations were less than 27 mM. The new system holds great promise for precision mixing in microfluidic devices using electrically driven flows.

Redox shuttles for overcharge protection of lithium batteries

DOEpatents

Amine, Khalil; Chen, Zonghai; Wang, Qingzheng

2010-12-14

The present invention is generally related to electrolytes containing novel redox shuttles for overcharge protection of lithium-ion batteries. The redox shuttles are capable of thousands hours of overcharge tolerance and have a redox potential at about 3-5.5 V vs. Li and particularly about 4.4-4.8 V vs. Li. Accordingly, in one aspect the invention provides electrolytes comprising an alkali metal salt; a polar aprotic solvent; and a redox shuttle additive that is an aromatic compound having at least one aromatic ring with four or more electronegative substituents, two or more oxygen atoms bonded to the aromatic ring, and no hydrogen atoms bonded to the aromatic ring; and wherein the electrolyte solution is substantially non-aqueous. Further there are provided electrochemical devices employing the electrolyte and methods of making the electrolyte.

Substituted Quaternary Ammonium Salts Improve Low-Temperature Performance of Double-Layer Capacitors

NASA Technical Reports Server (NTRS)

Brandon, Erik J.; Smart, Marshall C.; West, William C.

2011-01-01

Double-layer capacitors are unique energy storage devices, capable of supporting large current pulses as well as a very high number of charging and discharging cycles. The performance of doublelayer capacitors is highly dependent on the nature of the electrolyte system used. Many applications, including for electric and fuel cell vehicles, back-up diesel generators, wind generator pitch control back-up power systems, environmental and structural distributed sensors, and spacecraft avionics, can potentially benefit from the use of double-layer capacitors with lower equivalent series resistances (ESRs) over wider temperature limits. Higher ESRs result in decreased power output, which is a particular problem at lower temperatures. Commercially available cells are typically rated for operation down to only 40 C. Previous briefs [for example, Low Temperature Supercapacitors (NPO-44386), NASA Tech Briefs, Vol. 32, No. 7 (July 2008), p. 32, and Supercapacitor Electrolyte Solvents With Liquid Range Below 80 C (NPO-44855), NASA Tech Briefs, Vol. 34, No. 1 (January 2010), p. 44] discussed the use of electrolytes that employed low-melting-point co-solvents to depress the freezing point of traditional acetonitrile-based electrolytes. Using these modified electrolyte formulations can extend the low-temperature operational limit of double-layer capacitors beyond that of commercially available cells. This previous work has shown that although the measured capacitance is relatively insensitive to temperature, the ESR can rise rapidly at low temperatures, due to decreased electrolyte conductance within the pores of the high surface- area carbon electrodes. Most of these advanced electrolyte systems featured tetraethylammonium tetrafluoroborate (TEATFB) as the salt. More recent work at JPL indicates the use of the asymmetric quaternary ammonium salt triethylmethylammonium tetrafluoroborate (TEMATFB) or spiro-(l,l')-bipyrrolidium tetrafluoroborate (SBPBF4) in a 1:1 by volume solvent mixture of acetonitrile (AN) and methyl formate (MF) enables double-layer capacitor cells to operate well below -40 C with a relatively low ESR. Typically, a less than twofold increase in ESR is observed at -65 C relative to room-temperature values, when these modified electrolyte blends are used in prototype cells. Double-layer capacitor coin cells filled with these electrolytes have displayed the lowest measured ESR for an organic electrolyte to date at low temperature (based on a wide range of electrolyte screening studies at JPL). The cells featured high-surface-area (approximately equal to 2,500 m/g) carbon electrodes that were 0.50 mm thick and 1.6 cm in diameter, and coated with a thin layer of platinum to reduce cell resistance. A polyethylene separator was used to electrically isolate the electrodes.

Method of making a layered composite electrode/electrolyte

DOEpatents

Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

2005-01-25

An electrode/electrolyte structure is prepared by a plurality of methods. An unsintered (possibly bisque fired) moderately catalytic electronically-conductive or homogeneous mixed ionic electronic conductive electrode material is deposited on a layer composed of a sintered or unsintered ionically-conductive electrolyte material prior to being sintered. A layer of particulate electrode material is deposited on an unsintered ("green") layer of electrolyte material and the electrode and electrolyte layers are sintered simultaneously, sometimes referred to as "co-firing," under conditions suitable to fully densify the electrolyte while the electrode retains porosity. Or, the layer of particulate electrode material is deposited on a previously sintered layer of electrolyte, and then sintered. Subsequently, a catalytic material is added to the electrode structure by infiltration of an electrolcatalyst precursor (e.g., a metal salt such as a transition metal nitrate). This may be followed by low temperature firing to convert the precursor to catalyst. The invention allows for an electrode with high electronic conductivity and sufficient catalytic activity to achieve high power density in an ionic (electrochemical) device such as fuel cells and electrolytic gas separation systems.

Electro-catalytic oxidation device for removing carbon from a fuel reformate

DOEpatents

Liu, Di-Jia [Naperville, IL

2010-02-23

An electro-catalytic oxidation device (ECOD) for the removal of contaminates, preferably carbonaceous materials, from an influent comprising an ECOD anode, an ECOD cathode, and an ECOD electrolyte. The ECOD anode is at a temperature whereby the contaminate collects on the surface of the ECOD anode as a buildup. The ECOD anode is electrically connected to the ECOD cathode, which consumes the buildup producing electricity and carbon dioxide. The ECOD anode is porous and chemically active to the electro-catalytic oxidation of the contaminate. The ECOD cathode is exposed to oxygen, and made of a material which promotes the electro-chemical reduction of oxygen to oxidized ions. The ECOD electrolyte is non-permeable to gas, electrically insulating and a conductor to oxidized. The ECOD anode is connected to the fuel reformer and the fuel cell. The ECOD electrolyte is between and in ionic contact with the ECOD anode and the ECOD cathode.

Atomic Layer Deposition Alumina-Passivated Silicon Nanowires: Probing the Transition from Electrochemical Double-Layer Capacitor to Electrolytic Capacitor.

PubMed

Gaboriau, Dorian; Boniface, Maxime; Valero, Anthony; Aldakov, Dmitry; Brousse, Thierry; Gentile, Pascal; Sadki, Said

2017-04-19

Silicon nanowires were coated by a 1-5 nm thin alumina layer by atomic layer deposition (ALD) in order to replace poorly reproducible and unstable native silicon oxide by a highly conformal passivating alumina layer. The surface coating enabled probing the behavior of symmetric devices using such electrodes in the EMI-TFSI electrolyte, allowing us to attain a large cell voltage up to 6 V in ionic liquid, together with very high cyclability with less than 4% capacitance fade after 10 6 charge/discharge cycles. These results yielded fruitful insights into the transition between an electrochemical double-layer capacitor behavior and an electrolytic capacitor behavior. Ultimately, thin ALD dielectric coatings can be used to obtain hybrid devices exhibiting large cell voltage and excellent cycle life of dielectric capacitors, while retaining energy and power densities close to the ones displayed by supercapacitors.

All-tantalum electrolytic capacitor

NASA Technical Reports Server (NTRS)

Green, G. E., Jr.

1977-01-01

Device uses single-compression tantalum-to-tantalum seal. Single-compression seal allows better utilization of volume within device. As result of all-tantalum case and lengthened cathode, electrical parameters, particularly equivalent series resistance and capacitance stability, improved over silver-cased capacitor.

All-solid-state reduced graphene oxide supercapacitor with large volumetric capacitance and ultralong stability prepared by electrophoretic deposition method.

PubMed

Wang, Mei; Duong, Le Dai; Mai, Nguyen Thi; Kim, Sanghoon; Kim, Youngjun; Seo, Heewon; Kim, Ye Chan; Jang, Woojin; Lee, Youngkwan; Suhr, Jonghwan; Nam, Jae-Do

2015-01-21

Portable energy storage devices have gained special attention due to the growing demand for portable electronics. Herein, an all-solid-state supercapacitor is successfully fabricated based on a poly(vinyl alcohol)-H3PO4 (PVA-H3PO4) polymer electrolyte and a reduced graphene oxide (RGO) membrane electrode prepared by electrophoretic deposition (EPD). The RGO electrode fabricated by EPD contains an in-plane layer-by-layer alignment and a moderate porosity that accommodate the electrolyte ions. The all-solid-state RGO supercapacitor is thoroughly tested to give high specific volumetric capacitance (108 F cm(-3)) and excellent energy and power densities (7.5 Wh cm(-3) and 2.9 W cm(-3), respectively). In addition, the all-solid-state RGO supercapacitor exhibits an ultralong lifetime for as long as 180 days (335 000 cycles), which is an ultrahigh cycling capability for a solid-state supercapacitor. The RGO is also tested for being used as a transparent supercapacitor electrode demonstrating its possible use in various transparent optoelectronic devices. Due to the facile scale-up capability of the EPD process and RGO dispersion, the developed all-solid-state supercapacitor is highly applicable to large-area portable energy storage devices.

High performance ultracapacitors with carbon nanomaterials and ionic liquids

DOEpatents

Lu, Wen; Henry, Kent Douglas

2012-10-09

The present invention is directed to the use of carbon nanotubes and/or electrolyte structures in various electrochemical devices, such as ultracapacitors having an ionic liquid electrolyte. The carbon nanotubes are preferably aligned carbon nanotubes. Compared to randomly entangled carbon nanotubes, aligned carbon nanotubes can have better defined pore structures and higher specific surface areas.

Development of Titanium-Sputtered Anodized Aluminum Substrates for Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Côté, Marie-Pier; Parsi Benehkohal, Nima; Alpay, Neslihan; Demopoulos, George P.; Brochu, Mathieu

2014-12-01

In this study, anodized aluminum coupons are sputtered with titanium and successfully demonstrated as dye-sensitized solar cell (DSC) electrode substrates in both anode [back-illumination (BI)] and cathode [front-illumination (FI)] configurations. The FI DSCs were found to be significantly more efficient than the BI devices registering an average efficiency of 5.7 vs 2.6 pct. By comparison, the efficiency of benchmark cells built with fluorine-tin oxide-glass was 6.7 and 4.6 pct, respectively. The thickness of the titanium-sputtered film was varied from 0.85 to 1.1 μm with the latter providing a better average efficiency when used as a counter electrode. According to preliminary stability testing, the Ti-sputtered anodized aluminum-based DSC devices exhibited a significant reduction of their efficiency over a period of 10 days that was partly attributed to triiodide redox electrolyte reaction with the aluminum substrate. This points to the need for optimization of the sputtered-titanium coating microstructure in order to completely isolate the aluminum substrate from the liquid electrolyte.

Ion Dynamics in a Mixed-Cation Alkoxy-Ammonium Ionic Liquid Electrolyte for Sodium Device Applications.

PubMed

Pope, Cameron R; Kar, Mega; MacFarlane, Douglas R; Armand, Michel; Forsyth, Maria; O'Dell, Luke A

2016-10-18

The ion dynamics in a novel sodium-containing room-temperature ionic liquid (IL) consisting of an ether-functionalised quaternary ammonium cation and bis(trifluoromethylsulfonyl)amide [NTf 2 ] anion with various concentrations of Na[NTf 2 ] have been characterised using differential scanning calorimetry, impedance spectroscopy, diffusometry and NMR relaxation measurements. The IL studied has been specifically designed to dissolve a relatively large concentration of Na[NTf 2 ] salt (over 2 mol kg -1 ) as this has been shown to improve ion transport and conductivity. Consistent with other studies, the measured ionic conductivity and diffusion coefficients show that the overall ionic mobility decreases with decreasing temperature and increasing salt content. NMR relaxation measurements provide evidence for correlated dynamics between the ether-functionalised ammonium and Na cations, possibly with the latter species acting as cross-links between multiple ammonium cations. Finally, preliminary cyclic voltammetry experiments show that this IL can undergo stable electrochemical cycling and could therefore be potentially useful as an electrolyte in a Na-based device. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Voltage switching of a VO{sub 2} memory metasurface using ionic gel

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

Goldflam, M. D.; Liu, M. K.; Chapler, B. C.

2014-07-28

We demonstrate an electrolyte-based voltage tunable vanadium dioxide (VO{sub 2}) memory metasurface. Large spatial scale, low voltage, non-volatile switching of terahertz (THz) metasurface resonances is achieved through voltage application using an ionic gel to drive the insulator-to-metal transition in an underlying VO{sub 2} layer. Positive and negative voltage application can selectively tune the metasurface resonance into the “off” or “on” state by pushing the VO{sub 2} into a more conductive or insulating regime respectively. Compared to graphene based control devices, the relatively long saturation time of resonance modification in VO{sub 2} based devices suggests that this voltage-induced switching originates primarilymore » from electrochemical effects related to oxygen migration across the electrolyte–VO{sub 2} interface.« less

High-Energy-Density Electrolytic Capacitors

NASA Technical Reports Server (NTRS)

Yen, Shiao-Ping S.; Lewis, Carol R.

1993-01-01

Reductions in weight and volume make new application possible. Supercapacitors and improved ultracapacitors advanced electrolytic capacitors developed for use as electric-load-leveling devices in such applications as electric vehicle propulsion systems, portable power tools, and low-voltage pulsed power supplies. One primary advantage: offer power densities much higher than storage batteries. Capacitors used in pulse mode, with short charge and discharge times. Derived from commercially available ultracapacitors. Made of lightweight materials; incorporate electrode/electrolyte material systems capable of operation at voltages higher than previous electrode/electrolyte systems. By use of innovative designs and manufacturing processes, made in wide range of rated capacitances and in rated operating potentials ranging from few to several hundred volts.

Electrochemically driven mechanical energy harvesting.

PubMed

Kim, Sangtae; Choi, Soon Ju; Zhao, Kejie; Yang, Hui; Gobbi, Giorgia; Zhang, Sulin; Li, Ju

2016-01-06

Efficient mechanical energy harvesters enable various wearable devices and auxiliary energy supply. Here we report a novel class of mechanical energy harvesters via stress-voltage coupling in electrochemically alloyed electrodes. The device consists of two identical Li-alloyed Si as electrodes, separated by electrolyte-soaked polymer membranes. Bending-induced asymmetric stresses generate chemical potential difference, driving lithium ion flux from the compressed to the tensed electrode to generate electrical current. Removing the bending reverses ion flux and electrical current. Our thermodynamic analysis reveals that the ideal energy-harvesting efficiency of this device is dictated by the Poisson's ratio of the electrodes. For the thin-film-based energy harvester used in this study, the device has achieved a generating capacity of 15%. The device demonstrates a practical use of stress-composition-voltage coupling in electrochemically active alloys to harvest low-grade mechanical energies from various low-frequency motions, such as everyday human activities.

Electrochemically driven mechanical energy harvesting

PubMed Central

Kim, Sangtae; Choi, Soon Ju; Zhao, Kejie; Yang, Hui; Gobbi, Giorgia; Zhang, Sulin; Li, Ju

2016-01-01

Efficient mechanical energy harvesters enable various wearable devices and auxiliary energy supply. Here we report a novel class of mechanical energy harvesters via stress–voltage coupling in electrochemically alloyed electrodes. The device consists of two identical Li-alloyed Si as electrodes, separated by electrolyte-soaked polymer membranes. Bending-induced asymmetric stresses generate chemical potential difference, driving lithium ion flux from the compressed to the tensed electrode to generate electrical current. Removing the bending reverses ion flux and electrical current. Our thermodynamic analysis reveals that the ideal energy-harvesting efficiency of this device is dictated by the Poisson's ratio of the electrodes. For the thin-film-based energy harvester used in this study, the device has achieved a generating capacity of 15%. The device demonstrates a practical use of stress-composition–voltage coupling in electrochemically active alloys to harvest low-grade mechanical energies from various low-frequency motions, such as everyday human activities. PMID:26733282

Graphene based terahertz phase modulators

NASA Astrophysics Data System (ADS)

Kakenov, N.; Ergoktas, M. S.; Balci, O.; Kocabas, C.

2018-07-01

Electrical control of amplitude and phase of terahertz radiation (THz) is the key technological challenge for high resolution and noninvasive THz imaging. The lack of active materials and devices hinders the realization of these imaging systems. Here, we demonstrate an efficient terahertz phase and amplitude modulation using electrically tunable graphene devices. Our device structure consists of electrolyte-gated graphene placed at quarter wavelength distance from a reflecting metallic surface. In this geometry, graphene operates as a tunable impedance surface which yields electrically controlled reflection phase. Terahertz time domain reflection spectroscopy reveals the voltage controlled phase modulation of π and the reflection modulation of 50 dB. To show the promises of our approach, we demonstrate a multipixel phase modulator array which operates as a gradient impedance surface.

Electrochemical Exfoliation of Graphite in Aqueous Sodium Halide Electrolytes toward Low Oxygen Content Graphene for Energy and Environmental Applications.

PubMed

Munuera, J M; Paredes, J I; Enterría, M; Pagán, A; Villar-Rodil, S; Pereira, M F R; Martins, J I; Figueiredo, J L; Cenis, J L; Martínez-Alonso, A; Tascón, J M D

2017-07-19

Graphene and graphene-based materials have shown great promise in many technological applications, but their large-scale production and processing by simple and cost-effective means still constitute significant issues in the path of their widespread implementation. Here, we investigate a straightforward method for the preparation of a ready-to-use and low oxygen content graphene material that is based on electrochemical (anodic) delamination of graphite in aqueous medium with sodium halides as the electrolyte. Contrary to previous conflicting reports on the ability of halide anions to act as efficient exfoliating electrolytes in electrochemical graphene exfoliation, we show that proper choice of both graphite electrode (e.g., graphite foil) and sodium halide concentration readily leads to the generation of large quantities of single-/few-layer graphene nanosheets possessing a degree of oxidation (O/C ratio down to ∼0.06) lower than that typical of anodically exfoliated graphenes obtained with commonly used electrolytes. The halide anions are thought to play a role in mitigating the oxidation of the graphene lattice during exfoliation, which is also discussed and rationalized. The as-exfoliated graphene materials exhibited a three-dimensional morphology that was suitable for their practical use without the need to resort to any kind of postproduction processing. When tested as dye adsorbents, they outperformed many previously reported graphene-based materials (e.g., they adsorbed ∼920 mg g -1 for methyl orange) and were useful sorbents for oils and nonpolar organic solvents. Supercapacitor cells assembled directly from the as-exfoliated products delivered energy and power density values (up to 15.3 Wh kg -1 and 3220 W kg -1 , respectively) competitive with those of many other graphene-based devices but with the additional advantage of extreme simplicity of preparation.

Ionogel Electrolytes through Sol-Gel Processing

NASA Astrophysics Data System (ADS)

Horowitz, Ariel I.

Electrical energy needs have intensified due to the ubiquity of personal electronics, the decarbonization of energy services through electrification, and the use of intermittent renewable energy sources. Despite developments in mechanical and thermal methods, electrochemical technologies are the most convenient and effective means of storing electrical energy. These technologies include both electrochemical cells, commonly called batteries, and electrochemical double-layer capacitors, or "supercapacitors", which store energy electrostatically. Both device types require an ion-conducting electrolyte. Current devices use solutions of complex salts in organic solvents, leading to both toxicity and flammability concerns. These drawbacks can be avoided by replacing conventional electrolytes with room-temperature molten salts, known as ionic liquids (ILs). ILs are non-volatile, non-flammable, and offer high conductivity and good electrochemical stability. Device mass can be reduced by combining ILs with a solid scaffold material to form an "ionogel," further improving performance metrics. In this work, sol-gel chemistry is explored as a means of forming ionogel electrolytes. Sol-gel chemistry is a solution-based, industrially-relevant, well-studied technique by which solids such as silica can be formed in situ. Previous works used a simple acid-catalyzed sol-gel reaction to create brittle, glassy ionogels. Here, both the range of products that can be accomplished through sol-gel processing and the understanding of interactions between ILs and the sol-gel reaction network are greatly expanded. This work introduces novel ionogel materials, including soft and compliant silica-supported ionogels and PDMS-supported ionogels. The impacts of the reactive formulation, IL identity, and casting time are detailed. It is demonstrated that variations in formulation can lead to rapid gelation and open pore structures in the silica scaffold or slow gelation and more dense silica morphologies. The IL identity is shown to have an impact on the apparent strength of the acid catalyst, leading to significant shifts in gelation time. Delayed casting is proven to be an optimal technique for avoiding pore blockage when combining ionogels with high surface area electrodes for supercapacitor applications. Finally, a simple recycling process is proposed, establishing that ILs can be easily reclaimed from silica-supported ionogels and reused, thereby validating the reputation of ILs as "green" materials.

Zinc oxide nanoring embedded lacey graphene nanoribbons in symmetric/asymmetric electrochemical capacitive energy storage

NASA Astrophysics Data System (ADS)

Sahu, Vikrant; Goel, Shubhra; Sharma, Raj Kishore; Singh, Gurmeet

2015-12-01

This article describes the synthesis and characterization of ZnO nanoring embedded graphene nanoribbons. Patterned holes (mesopore dia.) in graphene nanoribbons are chemically generated, leading to a high density of the edge planes. These planes carry negatively charged surface groups (like -COOH and -OH) and therefore anchor the metal ions in a cordial fashion forming a string of metal ions along the edge planes. These strings of imbibed metal ions precipitate as tiny ZnO nanorings over lacey graphene nanoribbons. The thus obtained graphene nanoribbon (GNR) based hierarchical ZnO mesoporous structures are three dimensionally accessible to the electrolyte and demonstrate high performance in capacitive energy storage. The ZnO/GNR nanocomposite electrode in an asymmetric supercapacitor device with lacey reduced graphene oxide nanoribbons (LRGONRs) as a negative electrode exhibits a 2.0 V potential window in the aqueous electrolyte and an ultra-short time constant (0.08 s). The wide potential window consequently increased the energy density from 6.8 Wh kg-1 (ZnO/GNR symmetric) to 9.4 Wh kg-1 (ZnO/GNR||LRGONR asymmetric). The relaxation time constant obtained for the asymmetric supercapacitor device was three orders of magnitude less compared to the ZnO (symmetric, 33 s) supercapacitor device. The high cycling stability of ZnO/GNR||LRGONR up to 96.7% capacitance retention, after 5000 GCD cycles at 2 mA cm-2, paves the way to a high performance aqueous electrochemical supercapacitive energy storage.This article describes the synthesis and characterization of ZnO nanoring embedded graphene nanoribbons. Patterned holes (mesopore dia.) in graphene nanoribbons are chemically generated, leading to a high density of the edge planes. These planes carry negatively charged surface groups (like -COOH and -OH) and therefore anchor the metal ions in a cordial fashion forming a string of metal ions along the edge planes. These strings of imbibed metal ions precipitate as tiny ZnO nanorings over lacey graphene nanoribbons. The thus obtained graphene nanoribbon (GNR) based hierarchical ZnO mesoporous structures are three dimensionally accessible to the electrolyte and demonstrate high performance in capacitive energy storage. The ZnO/GNR nanocomposite electrode in an asymmetric supercapacitor device with lacey reduced graphene oxide nanoribbons (LRGONRs) as a negative electrode exhibits a 2.0 V potential window in the aqueous electrolyte and an ultra-short time constant (0.08 s). The wide potential window consequently increased the energy density from 6.8 Wh kg-1 (ZnO/GNR symmetric) to 9.4 Wh kg-1 (ZnO/GNR||LRGONR asymmetric). The relaxation time constant obtained for the asymmetric supercapacitor device was three orders of magnitude less compared to the ZnO (symmetric, 33 s) supercapacitor device. The high cycling stability of ZnO/GNR||LRGONR up to 96.7% capacitance retention, after 5000 GCD cycles at 2 mA cm-2, paves the way to a high performance aqueous electrochemical supercapacitive energy storage. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06083d

Spectroscopic Studies of the Electronic Structure of Metal-Semiconductor and Vacuum-Semiconductor Interfaces.

DTIC Science & Technology

1982-12-31

interfaces which are of importance in such semi- conductor devices as MOSFETS, CCD devices, photovoltaic devices, DD I jAN 73 1473 EDITION OF INOV 66 if...interfaces is interesting for the study of electrolytic cells . Our photoemission study reveals for the first time how the electronic structure of water

Flexible graphene-PZT ferroelectric nonvolatile memory.

PubMed

Lee, Wonho; Kahya, Orhan; Toh, Chee Tat; Ozyilmaz, Barbaros; Ahn, Jong-Hyun

2013-11-29

We report the fabrication of a flexible graphene-based nonvolatile memory device using Pb(Zr0.35,Ti0.65)O3 (PZT) as the ferroelectric material. The graphene and PZT ferroelectric layers were deposited using chemical vapor deposition and sol–gel methods, respectively. Such PZT films show a high remnant polarization (Pr) of 30 μC cm−2 and a coercive voltage (Vc) of 3.5 V under a voltage loop over ±11 V. The graphene–PZT ferroelectric nonvolatile memory on a plastic substrate displayed an on/off current ratio of 6.7, a memory window of 6 V and reliable operation. In addition, the device showed one order of magnitude lower operation voltage range than organic-based ferroelectric nonvolatile memory after removing the anti-ferroelectric behavior incorporating an electrolyte solution. The devices showed robust operation in bent states of bending radii up to 9 mm and in cycling tests of 200 times. The devices exhibited remarkable mechanical properties and were readily integrated with plastic substrates for the production of flexible circuits.

Advances in high temperature components for AMTEC (alkali metal thermal-to-electric converter)

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

Williams, R.M.; Jeffries-Nakamura, B.; Underwood, M.L.

1991-12-31

Long lifetimes are required for AMTEC (or sodium heat engine) components for aerospace and terrestrial applications, and the high heat input temperature as well as the alkali metal liquid and vapor environment places unusual demands on the materials used to construct AMTEC devices. In addition, it is important to maximize device efficiency and power density, while maintaining a long life capability. In addition to the electrode, which must provide both efficient electrode kinetics, transport of the alkali metal, and low electrical resistance, other high temperature components of the cell face equally demanding requirements. The beta{double_prime} alumina solid electrolyte (BASE), themore » seal between the BASE ceramic and its metallic transition to the hot alkali metal (liquid or vapor) source, and metallic components of the device are exposed to hot liquid alkali metal. Modification of AMTEC components may also be useful in optimizing the device for particular operating conditions. In particular, a potassium AMTEC may be expected to operate more efficiently at lower temperatures.« less

Advances in high temperature components for AMTEC (alkali metal thermal-to-electric converter)

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

Williams, R.M.; Jeffries-Nakamura, B.; Underwood, M.L.

1991-01-01

Long lifetimes are required for AMTEC (or sodium heat engine) components for aerospace and terrestrial applications, and the high heat input temperature as well as the alkali metal liquid and vapor environment places unusual demands on the materials used to construct AMTEC devices. In addition, it is important to maximize device efficiency and power density, while maintaining a long life capability. In addition to the electrode, which must provide both efficient electrode kinetics, transport of the alkali metal, and low electrical resistance, other high temperature components of the cell face equally demanding requirements. The beta{double prime} alumina solid electrolyte (BASE),more » the seal between the BASE ceramic and its metallic transition to the hot alkali metal (liquid or vapor) source, and metallic components of the device are exposed to hot liquid alkali metal. Modification of AMTEC components may also be useful in optimizing the device for particular operating conditions. In particular, a potassium AMTEC may be expected to operate more efficiently at lower temperatures.« less

High power, gel polymer lithium-ion cells with improved low temperature performance for NASA and DoD applications

NASA Technical Reports Server (NTRS)

Smart, M. C.; Ratnakumar, B. V.; Whitcanack, L. D.; Chin, K. B.; Surampudi, S.; Narayanan, S. R.; Alamgir, Mohamed; Yu, Ji-Sang; Plichta, Edward P.

2004-01-01

Both NASA and the U.S. Army have interest in developing secondary energy storage devices that are capable of meeting the demanding performance requirements of aerospace and man-portable applications. In order to meet these demanding requirements, gel-polymer electrolyte-based lithium-ion cells are being actively considered, due to their promise of providing high specific energy and enhanced safety aspects.

Recent Developments of All-Solid-State Lithium Secondary Batteries with Sulfide Inorganic Electrolytes.

PubMed

Xu, Ruochen; Zhang, Shengzhao; Wang, Xiuli; Xia, Yan; Xia, Xinhui; Wu, Jianbo; Gu, Changdong; Tu, Jiangping

2018-04-20

Due to the increasing demand of security and energy density, all-solid-state lithium ion batteries have become the promising next-generation energy storage devices to replace the traditional liquid batteries with flammable organic electrolytes. In this Minireview, we focus on the recent developments of sulfide inorganic electrolytes for all-solid-state batteries. The challenges of assembling bulk-type all-solid-state batteries for industrialization are discussed, including low ionic conductivity of the present sulfide electrolytes, high interfacial resistance and poor compatibility between electrolytes and electrodes. Many efforts have been focused on the solutions for these issues. Although some progresses have been achieved, it is still far away from practical application. The perspectives for future research on all-solid-state lithium ion batteries are presented. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elaboration of a microstructured inkjet-printed carbon electrochemical capacitor

NASA Astrophysics Data System (ADS)

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

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

Artificial Synaptic Devices Based on Natural Chicken Albumen Coupled Electric-Double-Layer Transistors

NASA Astrophysics Data System (ADS)

Wu, Guodong; Feng, Ping; Wan, Xiang; Zhu, Liqiang; Shi, Yi; Wan, Qing

2016-03-01

Recent progress in using biomaterials to fabricate functional electronics has got growing attention for the new generation of environmentally friendly and biocompatible electronic devices. As a kind of biological material with rich source, proteins are essential natural component of all organisms. At the same time, artificial synaptic devices are of great significance for neuromorphic systems because they can emulate the signal process and memory behaviors of biological synapses. In this report, natural chicken albumen with high proton conductivity was used as the coupling electrolyte film for organic/inorganic hybrid synaptic devices fabrication. Some important synaptic functions including paired-pulse facilitation, dynamic filtering, short-term to long-term memory transition and spatial summation and shunting inhibition were successfully mimicked. Our results are very interesting for biological friendly artificial neuron networks and neuromorphic systems.

Integrated Microbatteries for Implantable Medical Devices

NASA Technical Reports Server (NTRS)

Whitacre, Jay; West, William

2008-01-01

Integrated microbatteries have been proposed to satisfy an anticipated need for long-life, low-rate primary batteries, having volumes less than 1 mm3, to power electronic circuitry in implantable medical devices. In one contemplated application, such a battery would be incorporated into a tubular hearing-aid device to be installed against an eardrum. This device is based on existing tube structures that have already been approved by the FDA for use in human ears. As shown in the figure, the battery would comprise a single cell at one end of the implantable tube. A small volume of Li-based primary battery cathode material would be compacted and inserted in the tube near one end, followed by a thin porous separator, followed by a pressed powder of a Li-containing alloy. Current-collecting wires would be inserted, with suitably positioned insulators to prevent a short circuit. The battery would contain a liquid electrolyte consisting of a Li-based salt in an appropriate solvent. Hermetic seals would be created by plugging both ends with a waterproof polymer followed by deposition of parylene.

3 V omni-directionally stretchable one-body supercapacitors based on a single ion-gel matrix and carbon nanotubes.

PubMed

Kim, Wonbin; Kim, Woong

2016-06-03

Stretchable supercapacitors often have laminated structures consisting of electrode, electrolyte, and supporting layers. Since the layers are likely to be composed of different materials, delamination is a major cause of failure upon stretching. In this study, we demonstrate delamination-free stretchable supercapacitors where all the component layers are prepared with a single matrix, which is composed of a polymer, poly(vinylidene fluoride-hexafluoropropylene) and an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. Since the ionic liquid in the composite plays a role as both an electrolyte and a plasticizer, this composite can be used as an electrolyte and a supporting layer in the stretchable supercapacitor. The electrode layer can be fabricated by incorporating carbon nanotubes in the common matrix. Then, all the layers can be seamlessly fused into one body by dissolving the surface of the composite with acetone, which evaporates after the integration, leaving no borders between the layers. This one-body stretchable supercapacitor not only has high durability against repetitive stretches but also is stretchable in all directions. This feature clearly distinguishes them from conventional stretchable supercapacitors fabricated using buckled structures, which are stretchable only in one or two directions. Moreover, this supercapacitor has high cell voltage (∼3 V) owing to the ionic liquid-based gel electrolytes. Our demonstration of isotropically stretchable high-durability supercapacitors may have a great implication in the development of stretchable energy storage devices for real applications.

Electrochemical performance evaluations and safety investigations of pentafluoro(phenoxy)cyclotriphosphazene as a flame retardant electrolyte additive for application in lithium ion battery systems using a newly designed apparatus for improved self-extinguishing time measurements

NASA Astrophysics Data System (ADS)

Dagger, Tim; Lürenbaum, Constantin; Schappacher, Falko M.; Winter, Martin

2017-02-01

A modified self-extinguishing time (SET) device which enhances the reproducibility of the results is presented. Pentafluoro(phenoxy)cyclotriphosphazene (FPPN) is investigated as flame retardant electrolyte additive for lithium ion batteries (LIBs) in terms of thermal stability and electrochemical performance. SET measurements and adiabatic reaction calorimetry are applied to determine the flammability and the reactivity of a standard LIB electrolyte containing 5% FPPN. The results reveal that the additive-containing electrolyte is nonflammable for 10 s whereas the commercially available reference electrolyte inflames instantaneously after 1 s of ignition. The onset temperature of the safety enhanced electrolyte is delayed by ≈ 21 °C. Compatibility tests in half cells show that the electrolyte is reductively stable while the cyclic voltammogram indicates oxidative decomposition during the first cycle. Cycling experiments in full cells show improved cycling performance and rate capability, which can be attributed to cathode passivation during the first cycle. Post-mortem analysis of the electrolyte by gas chromatography-mass spectrometry confirms the presence of the additive in high amounts after 501 cycles which ensures enhanced safety of the electrolyte. The investigations present FPPN as stable electrolyte additive that improves the intrinsic safety of the electrolyte and its cycling performance at the same time.

Energy storage devices having anodes containing Mg and electrolytes utilized therein

DOEpatents

Shao, Yuyan; Liu, Jun

2015-08-18

For a metal anode in a battery, the capacity fade is a significant consideration. In energy storage devices having an anode that includes Mg, the cycling stability can be improved by an electrolyte having a first salt, a second salt, and an organic solvent. Examples of the organic solvent include diglyme, triglyme, tetraglyme, or a combination thereof. The first salt can have a magnesium cation and be substantially soluble in the organic solvent. The second salt can enhance the solubility of the first salt and can have a magnesium cation or a lithium cation. The first salt, the second salt, or both have a BH.sub.4 anion.

Determination of the Thermal Noise Limit of Graphene Biotransistors.

PubMed

Crosser, Michael S; Brown, Morgan A; McEuen, Paul L; Minot, Ethan D

2015-08-12

To determine the thermal noise limit of graphene biotransistors, we have measured the complex impedance between the basal plane of single-layer graphene and an aqueous electrolyte. The impedance is dominated by an imaginary component but has a finite real component. Invoking the fluctuation-dissipation theorem, we determine the power spectral density of thermally driven voltage fluctuations at the graphene/electrolyte interface. The fluctuations have 1/f(p) dependence, with p = 0.75-0.85, and the magnitude of fluctuations scales inversely with area. Our results explain noise spectra previously measured in liquid-gated suspended graphene devices and provide realistic targets for future device performance.

Thermal battery. [solid metal halide electrolytes with enhanced electrical conductance after a phase transition

DOEpatents

Carlsten, R.W.; Nissen, D.A.

1973-03-06

The patent describes an improved thermal battery whose novel design eliminates various disadvantages of previous such devices. Its major features include a halide cathode, a solid metal halide electrolyte which has a substantially greater electrical conductance after a phase transition at some temperature, and a means for heating its electrochemical cells to activation temperature.

Advanced Energy Storage and Conversion Devices

DTIC Science & Technology

2008-12-01

determined lithium-ion insertion mechanisms. 3.1 Background and Objectives Polymer electrolyte membrane fuel cells ( PEMFCs ) function by permitting...is one of the most critical components in the polymer electrolyte fuel cells. In recent years, PEMFCs have been identified as promising power...and residual hydrocarbons that are commonly produced by internal combustion engines. PEMFCs , due to their high efficiency and modularity of design

Solution processable semiconductor thin films: Correlation between morphological, structural, optical and charge transport properties

NASA Astrophysics Data System (ADS)

Isik, Dilek

This Ph.D. thesis is a result of multidisciplinary research bringing together fundamental concepts in thin film engineering, materials science, materials processing and characterization, electrochemistry, microfabrication, and device physics. Experiments were conducted by tackling scientific problems in the field of thin films and interfaces, with the aim to correlate the morphology, crystalline structure, electronic structure of thin films with the functional properties of the films and the performances of electronic devices based thereon. Furthermore, novel strategies based on interfacial phenomena at electrolyte/thin film interfaces were explored and exploited to control the electrical conductivity of the thin films. Three main chemical systems were the object of the studies performed during this Ph.D., two types of organic semiconductors (azomethine-based oligomers and polymers and soluble pentacene derivatives) and one metal oxide semiconductor (tungsten trioxide, WO3). To explore the morphological properties of the thin films, atomic force microscopy was employed. The morphological properties were further investigated by hyperspectral fluorescence microscopy and tentatively correlated to the charge transport properties of the films. X-ray diffraction (Grazing incidence XRD, GIXRD) was used to investigate the crystallinity of the film and the effect of the heat treatment on such crystallinity, as well as to understand the molecular arrangement of the organic molecules in the thin film. The charge transport properties of the films were evaluated in thin film transistor configuration. For electrolyte gated thin film transistors, time dependent transient measurements were conducted, in parallel to more conventional transistor characterizations, to explore the specific effects played on the gating by the anion and cation constituting the electrolyte. The capacitances of the electrical double layers at the electrolyte/WO3 interface were obtained from electrochemical impedance spectroscopy. In the context of ARTICLE 1, thin film transistors based on soluble pentacene derivatives (prepared by the research group directed by Professor J. Anthony, at the University of Kentucky) were fabricated and characterized. GIXRD results performed on the thin films suggested a molecular arrangement favorable to charge transport in the source-drain direction, with the pi-pi stacking direction perpendicular to the channel. In ARTICLE 1, HMDS-treated SiO 2 substrates were used, to improve the surface coverage and to limit charge trapping at the dielectric surface. AFM showed good film coverage. The transistors showed ambipolar characteristics, attributed to the good matching between Au electrode work function and highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the pentacene derivative. The work reported in ARTICLE 2 deals with pi-conjugated thiopheno-azomethines (both in oligomer and polymer form) and oligothiophene analogues. In the former case, couplings in the polymer are based on azomethine (-N=C-) moieties whereas in the latter case they are based on more conventional protocols (-C=C-). The effect of the coupling protocols on the corresponding thin film transistors behavior was studied. The key conclusion of this study was that thiopheno-azomethines thin films can be effectively incorporated into organic transistors: thin films of oligothiopheno-azomethines and the oligothiophenes exhibit p-type behavior whereas thin films of polythiopheno-azomethine exhibit an ambipolar behavior. The hole mobility of the heat-treated thin films of oligothiopheno-azomethines was three orders of magnitude higher compared to its oligothiophene analogue. AFM, coupled with hyperspectral fluorescence imaging, were used to investigate the micro- and nano-scale surface coverage. For the oligothiopheno-azomethine we were able to quantitatively deduce the surface coverage. To contribute to the exploration of innovative strategies for low power consuming solution based electronics and capitalizing on the expertise of the group in the synthesis of solution deposited WO3 films the electrolyte gating approach was explored in ARTICLE 3. Ionic liquids, that are molten salts at room temperature, were employed as the electrolyte. Ionic liquids are attractive for their low volatility, non-flammability, ionic conductivity and thermal and electrochemical stability. Thin films of WO3 were deposited onto pre-patterned ITO substrates (source-drain interelectrode distance, 1 mm) prepared by wet chemical etching. SEM and AFM showed an interconnected film nanostructure. Electrolyte gated WO3 thin film transistors making use of 1-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][TFSI]), 1-butyl-3-methyl imidazolium hexafluoro phosphate ([BMIM][PF6]), and 1-ethyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) showed an n-type transistor behavior. The possibility to obtain WO3 electrolyte gated transistors represents an opportunity to fabricate electronic devices working at relatively low operating voltages (about 1 V) by using simple fabrication techniques.

Direct Laser Writing of Graphene Made from Chemical Vapor Deposition for Flexible, Integratable Micro-Supercapacitors with Ultrahigh Power Output.

PubMed

Ye, Jianglin; Tan, Huabing; Wu, Shuilin; Ni, Kun; Pan, Fei; Liu, Jie; Tao, Zhuchen; Qu, Yan; Ji, Hengxing; Simon, Patrice; Zhu, Yanwu

2018-05-17

High-performance yet flexible micro-supercapacitors (MSCs) hold great promise as miniaturized power sources for increasing demand of integrated electronic devices. Herein, this study demonstrates a scalable fabrication of multilayered graphene-based MSCs (MG-MSCs), by direct laser writing (DLW) of stacked graphene films made from industry-scale chemical vapor deposition (CVD). Combining the dry transfer of multilayered CVD graphene films, DLW allows a highly efficient fabrication of large-areal MSCs with exceptional flexibility, diverse planar geometry, and capability of customer-designed integration. The MG-MSCs exhibit simultaneously ultrahigh energy density of 23 mWh cm -3 and power density of 1860 W cm -3 in an ionogel electrolyte. Notably, such MG-MSCs demonstrate an outstanding flexible alternating current line-filtering performance in poly(vinyl alcohol) (PVA)/H 2 SO 4 hydrogel electrolyte, indicated by a phase angle of -76.2° at 120 Hz and a resistance-capacitance constant of 0.54 ms, due to the efficient ion transport coupled with the excellent electric conductance of the planar MG microelectrodes. MG-polyaniline (MG-PANI) hybrid MSCs fabricated by DLW of MG-PANI hybrid films show an optimized capacitance of 3.8 mF cm -2 in PVA/H 2 SO 4 hydrogel electrolyte; an integrated device comprising MG-MSCs line filtering, MG-PANI MSCs, and pressure/gas sensors is demonstrated. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Additives and salts for dye-sensitized solar cells electrolytes: what is the best choice?

NASA Astrophysics Data System (ADS)

Bella, Federico; Sacco, Adriano; Pugliese, Diego; Laurenti, Marco; Bianco, Stefano

2014-10-01

A multivariate chemometric approach is proposed for the first time for performance optimization of I-/I3- liquid electrolytes for dye-sensitized solar cells (DSSCs). Over the years the system composed by iodide/triiodide redox shuttle dissolved in organic solvent has been enriched with the addition of different specific cations and chemical compounds to improve the photoelectrochemical behavior of the cell. However, usually such additives act favorably with respect to some of the cell parameters and negatively to others. Moreover, the combined action of different compounds often yields contradictory results, and from the literature it is not possible to identify an optimal recipe. We report here a systematic work, based on a multivariate experimental design, to statistically and quantitatively evaluate the effect of different additives on the photovoltaic performances of the device. The effect of cation size in iodine salts, the iodine/iodide ratio in the electrolyte and the effect of type and concentration of additives are mutually evaluated by means of a Design of Experiment (DoE) approach. Through this statistical method, the optimization of the overall parameters is demonstrated with a limited number of experimental trials. A 25% improvement on the photovoltaic conversion efficiency compared with that obtained with a commercial electrolyte is demonstrated.

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

NASA Astrophysics Data System (ADS)

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

2017-02-01

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

Static charge outside chamber induces dielectric breakdown of solid-state nanopore membranes

NASA Astrophysics Data System (ADS)

Matsui, Kazuma; Goto, Yusuke; Yanagi, Itaru; Yanagawa, Yoshimitsu; Ishige, Yu; Takeda, Ken-ichi

2018-04-01

Reducing device capacitance is effective for decreasing current noise observed in a solid-state nanopore-based DNA sequencer. On the other hand, we have recently found that voltage stress causes pinhole-like defects in such low-capacitance devices. The origin of voltage stress, however, has not been determined. In this research, we identified that a dominant origin is static charge on the outer surface of a flow cell. Even though the outer surface was not in direct contact with electrolytes in the flow cell, the charge induces high voltage stress on a membrane according to the capacitance coupling ratio of the flow cell to the membrane.

Enhanced electrochemical performance of monoclinic WO3 thin film with redox additive aqueous electrolyte.

PubMed

Shinde, Pragati A; Lokhande, Vaibhav C; Chodankar, Nilesh R; Ji, Taeksoo; Kim, Jin Hyeok; Lokhande, Chandrakant D

2016-12-01

To achieve the highest electrochemical performance for supercapacitor, it is very essential to find out a suitable pair of an active electrode material and an electrolyte. In the present work, a simple approach is employed to enhance the supercapacitor performance of WO3 thin film. The WO3 thin film is prepared by a simple and cost effective chemical bath deposition method and its electrochemical performance is tested in conventional (H2SO4) and redox additive [H2SO4+hydroquinone (HQ)] electrolytes. Two-fold increment in electrochemical performance for WO3 thin film is observed in redox additive aqueous electrolyte compared to conventional electrolyte. WO3 thin film showed maximum specific capacitance of 725Fg(-1), energy density of 25.18Whkg(-1) at current density of 7mAcm(-2) with better cycling stability in redox electrolyte. This strategy provides the versatile way for designing the high performance energy storage devices. Copyright © 2016 Elsevier Inc. All rights reserved.

Towards Versatile and Sustainable Hydrogen Production through Electrocatalytic Water Splitting: Electrolyte Engineering.

PubMed

Shinagawa, Tatsuya; Takanabe, Kazuhiro

2017-04-10

Recent advances in power generation from renewable resources necessitate conversion of electricity to chemicals and fuels in an efficient manner. Electrocatalytic water splitting is one of the most powerful and widespread technologies. The development of highly efficient, inexpensive, flexible, and versatile water electrolysis devices is desired. This review discusses the significance and impact of the electrolyte on electrocatalytic performance. Depending on the circumstances under which the water splitting reaction is conducted, the required solution conditions, such as the identity and molarity of ions, may significantly differ. Quantitative understanding of such electrolyte properties on electrolysis performance is effective to facilitate the development of efficient electrocatalytic systems. The electrolyte can directly participate in reaction schemes (kinetics), affect electrode stability, and/or indirectly impact the performance by influencing the concentration overpotential (mass transport). This review aims to guide fine-tuning of the electrolyte properties, or electrolyte engineering, for (photo)electrochemical water splitting reactions. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Promising and Reversible Electrolyte with Thermal Switching Behavior for Safer Electrochemical Storage Devices.

PubMed

Shi, Yunhui; Zhang, Qian; Zhang, Yan; Jia, Limin; Xu, Xinhua

2018-02-28

A major stumbling block in large-scale adoption of high-energy-density electrochemical devices has been safety issues. Methods to control thermal runaway are limited by providing a one-time thermal protection. Herein, we developed a simple and reversible thermoresponsive electrolyte system that is efficient to shutdown the current flow according to temperature changes. The thermal management is ascribed to the thermally activated sol-gel transition of methyl cellulose solution, associated with the concentration of ions that can move between isolated chains freely or be restricted by entangled molecular chains. We studied the effect of cellulose concentration, substituent types, and operating temperature on the electrochemical performance, demonstrating an obvious capacity loss up to 90% approximately of its initial value. Moreover, this is a cost-effective approach that has the potential for use in practical electrochemical storage devices.

Dynamic Photoelectrochemical Device Using an Electrolyte-Permeable NiO x/SiO2/Si Photocathode with an Open-Circuit Potential of 0.75 V.

PubMed

Jung, Jin-Young; Yu, Jin-Young; Lee, Jung-Ho

2018-03-07

As a thermodynamic driving force obtained from sunlight, the open-circuit potential (OCP) in photoelectrochemical cells is typically limited by the photovoltage ( V ph ). In this work, we establish that the OCP can exceed the value of V ph when an electrolyte-permeable NiO x thin film is employed as an electrocatalyst in a Si photocathode. The built-in potential developed at the NiO x /Si junction is adjusted in situ according to the progress of the NiO x hydration for the hydrogen evolution reaction (HER). As a result of decoupling of the OCP from V ph , a high OCP value of 0.75 V (vs reversible hydrogen electrode) is obtained after 1 h operation of HER in an alkaline electrolyte (pH = 14), thus outperforming the highest value (0.64 V) reported to date with conventional Si photoelectrodes. This finding might offer insight into novel photocathode designs such as those based on tandem water-splitting systems.

Interfacial reactions in lithium batteries

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

Chen, Zonghai; Amine, Rachid; Ma, Zi-Feng

The lithium-ion battery was first commercially introduced by Sony Corporation on 1991 using LiCoO 2 as the cathode material and mesocarbon microbeads as the anode material. After continuous research and development for 25 years, lithium-ion batteries have been the dominant energy storage devices for modern portable electronics, as well as for the emerging application for electric vehicles and smart grids. It has been a common sense that the success of lithium-ion technologies is rooted to the existence of a solid electrolyte interphase (SEI) that kinetically suppresses the parasitic reactions between the lithiated 2 graphitic anodes and the carbonate-based non-aqueous electrolytes.more » Recently, major attention has been paid to the importance of a similar passivation/protection layer on the surface of cathode materials, aiming for rational design of high-energy-density lithiumion batteries with extended cycle/calendar life. In this article, the physical model of the solid electrolyte interphase, as well as the recent research effort to under the nature and role SEI are summarized, and future perspectives on this important research field will also be presented.« less

Interfacial reactions in lithium batteries

DOE PAGES

Chen, Zonghai; Amine, Rachid; Ma, Zi-Feng; ...

2017-06-29

The lithium-ion battery was first commercially introduced by Sony Corporation on 1991 using LiCoO 2 as the cathode material and mesocarbon microbeads as the anode material. After continuous research and development for 25 years, lithium-ion batteries have been the dominant energy storage devices for modern portable electronics, as well as for the emerging application for electric vehicles and smart grids. It has been a common sense that the success of lithium-ion technologies is rooted to the existence of a solid electrolyte interphase (SEI) that kinetically suppresses the parasitic reactions between the lithiated 2 graphitic anodes and the carbonate-based non-aqueous electrolytes.more » Recently, major attention has been paid to the importance of a similar passivation/protection layer on the surface of cathode materials, aiming for rational design of high-energy-density lithiumion batteries with extended cycle/calendar life. In this article, the physical model of the solid electrolyte interphase, as well as the recent research effort to under the nature and role SEI are summarized, and future perspectives on this important research field will also be presented.« less

Durability of PEM Fuel Cell Membranes

NASA Astrophysics Data System (ADS)

Huang, Xinyu; Reifsnider, Ken

Durability is still a critical limiting factor for the commercialization of polymer electrolyte membrane (PEM) fuel cells, a leading energy conversion technology for powering future hydrogen fueled automobiles, backup power systems (e.g., for base transceiver station of cellular networks), portable electronic devices, etc. Ionic conducting polymer (ionomer) electrolyte membranes are the critical enabling materials for the PEM fuel cells. They are also widely used as the central functional elements in hydrogen generation (e.g., electrolyzers), membrane cell for chlor-alkali production, etc. A perfluorosulfonic acid (PFSA) polymer with the trade name Nafion® developed by DuPont™ is the most widely used PEM in chlor-alkali cells and PEM fuel cells. Similar PFSA membranes have been developed by Dow Chemical, Asahi Glass, and lately Solvay Solexis. Frequently, such membranes serve the dual function of reactant separation and selective ionic conduction between two otherwise separate compartments. For some applications, the compromise of the "separation" function via the degradation and mechanical failure of the electrolyte membrane can be the life-limiting factor; this is particularly the case for PEM in hydrogen/oxygen fuel cells.

All-Ceramic Thin Film Battery

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

BOYLE, TIMOTHY J.; INGERSOLL, DAVID; CYGAN, RANDALL T.

2002-11-01

We have undertaken the synthesis of a thin film ''All Ceramic Battery'' (ACB) using solution route processes. Based on the literature and experimental results, we selected SnO{sub 2}, LiCoO{sub 2}, and LiLaTiO{sub 3} (LLT) as the anode, cathode, and electrolyte, respectively. Strain induced by lattice mismatch between the cathode and bottom electrode, as estimated by computational calculations, indicate that thin film orientations for batteries when thicknesses are as low as 500 {angstrom} are strongly controlled by surface energies. Therefore, we chose platinized silicon as the basal platform based on our previous experience with this material. The anode thin films weremore » generated by standard spin-cast methods and processing using a solution of [Sn(ONep)]{sub 8} and HOAc which was found to form Sn{sub 6}(O){sub 4}(ONep){sub 4}. Electrochemical evaluation showed that the SnO{sub 2} was converted to Sn{sup o} during the first cycle. The cathode was also prepared by spin coating using the novel [Li(ONep)]{sub 8} and Co(OAc){sub 2}. The films could be electrochemically cycled (i.e., charged/discharged), with all of the associated structural changes being observable by XRD. Computational models indicated that the LLT electrolyte would be the best available ceramic material for use as the electrolyte. The LLT was synthesized from [Li(ONep)]{sub 8}, [Ti(ONep){sub 4}]{sub 2}, and La(DIP){sub 3}(py){sub 3} with RTP processing at 900 C being necessary to form the perovskite phase. Alternatively, a novel route to thin films of the block co-polymer ORMOLYTE was developed. The integration of these components was undertaken with each part of the assembly being identifiably by XRD analysis (this will allow us to follow the progress of the charge/discharge cycles of the battery during use). SEM investigations revealed the films were continuous with minimal mixing. All initial testing of the thin-film cathode/electrolyte/anode ACB devices revealed electrical shorting. Alternative approaches for preparing non-shorted devices (e.g. inverted and side-by-side) are under study.« less

A Nonaqueous Potassium-Based Battery-Supercapacitor Hybrid Device.

PubMed

Fan, Ling; Lin, Kairui; Wang, Jue; Ma, Ruifang; Lu, Bingan

2018-05-01

A low cost nonaqueous potassium-based battery-supercapacitor hybrid device (BSH) is successfully established for the first time with soft carbon as the anode, commercialized activated carbon as the cathode, and potassium bis(fluoro-slufonyl)imide in dimethyl ether as the electrolyte. This BSH reconciles the advantages of potassium ion batteries and supercapacitors, achieving a high energy density of 120 W h kg -1 , a high power density of 599 W kg -1 , a long cycle life of 1500 cycles, and an ultrafast charge/slow discharge performance (energy density and power density are calculated based on the total mass of active materials in the anode and cathode). This work demonstrates a great potential of applying the nonaqueous BSH for low cost electric energy storage systems. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supercapacitor Operating At 200 Degrees Celsius

PubMed Central

Borges, Raquel S.; Reddy, Arava Leela Mohana; Rodrigues, Marco-Tulio F.; Gullapalli, Hemtej; Balakrishnan, Kaushik; Silva, Glaura G.; Ajayan, Pulickel M.

2013-01-01

The operating temperatures of current electrochemical energy storage devices are limited due to electrolyte degradation and separator instability at higher temperatures. Here we demonstrate that a tailored mixture of materials can facilitate operation of supercapacitors at record temperatures, as high as 200°C. Composite electrolyte/separator structures made from naturally occurring clay and room temperature ionic liquids, with graphitic carbon electrodes, show stable supercapacitor performance at 200°C with good cyclic stability. Free standing films of such high temperature composite electrolyte systems can become versatile functional membranes in several high temperature energy conversion and storage applications. PMID:23999206

Thin Film Electrodes with an Integral Current Collection Grid for Use with Solid Electrolytes

NASA Technical Reports Server (NTRS)

Ryan, M. A.; Kisor, A.; Williams, R. M.; Jeffries-Nakamura, B.; O'Connor, D.

1994-01-01

Thin film, high performance electrodes which can operate in high temperature environments are necessary for many devices which use a solid electrolyte. Electrodes of rhodium-tungsten alloy have been deposited on solid electrolyte using photolytic chemical vapor deposition (PCVD). A technique for depositing electrodes and current collection grids simultaneously has been developed using the prenucleation characteristics of PCVD. This technique makes it possible to fabricate electrodes which allow vapor transport through the thin (<1 (micro)m) portions of the electrode while integral thick grid lines improve the electronic conductivity of the electrode, thus improving overall performance.

Electrochemical devices utilizing molten alkali metal electrode-reactant

DOEpatents

Hitchcock, David C.; Mailhe, Catherine C.; De Jonghe, Lutgard C.

1986-01-01

Electrochemical cells are provided with a reactive metal to reduce the oxide of the alkali metal electrode-reactant. Cells employing a molten alkali metal electrode, e.g., sodium, in contact with a ceramic electrolyte, which is a conductor of the ions of the alkali metal forming the electrode, exhibit a lower resistance when a reactive metal, e.g., vanadium, is allowed to react with and reduce the alkali metal oxide. Such cells exhibit less degradation of the electrolyte and of the glass seals often used to joining the electrolyte to the other components of the cell under cycling conditions.

Electrochemical devices utilizing molten alkali metal electrode-reactant

DOEpatents

Hitchcock, D.C.; Mailhe, C.C.; De Jonghe, L.C.

1985-07-10

Electrochemical cells are provided with a reactive metal to reduce the oxide of the alkali metal electrode-reactant. Cells employing a molten alkali metal electrode, e.g., sodium, in contact with a ceramic electrolyte, which is a conductor of the ions of the alkali metal forming the electrode, exhibit a lower resistance when a reactive metal, e.g., vanadium, is allowed to react with and reduce the alkali metal oxide. Such cells exhibit less degradation of the electrolyte and of the glass seals often used to joining the electrolyte to the other components of the cell under cycling conditions.

Bismuth oxide nanotubes-graphene fiber-based flexible supercapacitors.

PubMed

Gopalsamy, Karthikeyan; Xu, Zhen; Zheng, Bingna; Huang, Tieqi; Kou, Liang; Zhao, Xiaoli; Gao, Chao

2014-08-07

Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm(-2) (for a single electrode) and 17.3 mF cm(-2) (for the whole device) at 0.1 mA cm(-2), respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics.

Electrokinetic Supercapacitor for Simultaneous Harvesting and Storage of Mechanical Energy.

PubMed

Yang, Peihua; Qu, Xiaopeng; Liu, Kang; Duan, Jiangjiang; Li, Jia; Chen, Qian; Xue, Guobin; Xie, Wenke; Xu, Zhimou; Zhou, Jun

2018-03-07

Energy harvesting and storage are two distinct processes that are generally achieved using two separated parts based on different physical and chemical principles. Here we report a self-charging electrokinetic supercapacitor that directly couples the energy harvesting and storage processes into one device. The device consists of two identical carbon nanotube/titanium electrodes, separated by a piece of anodic aluminum oxide nanochannels membrane. Pressure-driven electrolyte flow through the nanochannels generates streaming potential, which can be used to charge the capacitive electrodes, accomplishing simultaneous energy generation and storage. The device stores electric charge density of 0.4 mC cm -2 after fully charging under pressure of 2.5 bar. This work may offer a train of thought for the development of a new type of energy unit for self-powered systems.

Producing smart sensing films by means of organic field effect transistors.

PubMed

Manunza, Ileana; Orgiu, Emanuele; Caboni, Alessandra; Barbaro, Massimo; Bonfiglio, Annalisa

2006-01-01

We have fabricated the first example of totally flexible field effect device for chemical detection based on an organic field effect transistor (OFET) made by pentacene films grown on flexible plastic structures. The ion sensitivity is achieved by employing a thin Mylar foil as gate dielectric. A sensitivity of the device to the pH of the electrolyte solution has been observed A similar structure can be used also for detecting mechanical deformations on flexible surfaces. Thanks to the flexibility of the substrate and the low cost of the employed technology, these devices open the way for the production of flexible chemical and strain gauge sensors that can be employed in a variety of innovative applications such as wearable electronics, e-textiles, new man-machine interfaces.

Improving pH sensitivity by field-induced charge regulation in flexible biopolymer electrolyte gated oxide transistors

NASA Astrophysics Data System (ADS)

Liu, Ning; Gan, Lu; Liu, Yu; Gui, Weijun; Li, Wei; Zhang, Xiaohang

2017-10-01

Electrical manipulation of charged ions in electrolyte-gated transistors is crucial for enhancing the electric-double-layer (EDL) gating effect, thereby improving their sensing abilities. Here, indium-zinc-oxide (IZO) based thin-film-transistors (TFTs) are fabricated on flexible plastic substrate. Acid doped chitosan-based biopolymer electrolyte is used as the gate dielectric, exhibiting an extremely high EDL capacitance. By regulating the dynamic EDL charging process with special gate potential profiles, the EDL gating effect of the chitosan-gated TFT is enhanced, and then resulting in higher pH sensitivities. An extremely high sensitivity of ∼57.8 mV/pH close to Nernst limit is achieved when the gate bias of the TFT sensor sweeps at a rate of 10 mV/s. Additionally, an enhanced sensitivity of 2630% in terms of current variation with pH range from 11 to 3 is realized when the device is operated in the ion depletion mode with a negative gate bias of -0.7 V. Robust ionic modulation is demonstrated in such chitosan-gated sensors. Efficiently driving the charged ions in the chitosan-gated IZO-TFT provides a new route for ultrasensitive, low voltage, and low-cost biochemical sensing technologies.

Cell structure for electrochemical devices and method of making same

DOEpatents

Kaun, Thomas D.

1993-01-01

An electrochemical device comprises a plurality of cells, each cell including a laminate cell membrane, made up of a separator/electrolyte means interposed between alternating positive and negative electrodes, each type of electrode being respectively in common contact to a single current collector.

Pulsed Electrochemical Mass Spectrometry for Operando Tracking of Interfacial Processes in Small-Time-Constant Electrochemical Devices such as Supercapacitors.

PubMed

Batisse, Nicolas; Raymundo-Piñero, Encarnación

2017-11-29

A more detailed understanding of the electrode/electrolyte interface degradation during the charging cycle in supercapacitors is of great interest for exploring the voltage stability range and therefore the extractable energy. The evaluation of the gas evolution during the charging, discharging, and aging processes is a powerful tool toward determining the stability and energy capacity of supercapacitors. Here, we attempt to fit the gas analysis resolution to the time response of a low-gas-generation power device by adopting a modified pulsed electrochemical mass spectrometry (PEMS) method. The pertinence of the method is shown using a symmetric carbon/carbon supercapacitor operating in different aqueous electrolytes. The differences observed in the gas levels and compositions as a function of the cell voltage correlate to the evolution of the physicochemical characteristics of the carbon electrodes and to the electrochemical performance, giving a complete picture of the processes taking place at the electrode/electrolyte interface.

Nonstoichiometric fluorides—Solid electrolytes for electrochemical devices: A review

NASA Astrophysics Data System (ADS)

Sorokin, N. I.; Sobolev, B. P.

2007-09-01

The solid electrolytes with fluorine-ion conductivity that were revealed during the analysis of the phase diagrams of the MF m - RF n systems within the program of search for new multicomponent fluoride crystalline materials carried out at the Shubnikov Institute of Crystallography, Russian Academy of Sciences, are described. The most widespread and promising materials are the nonstoichiometric phases with fluorite (CaF2) and tysonite (LaF3) structures, which are formed in the MF2- RF3 systems ( M = Ca, Sr, Ba, Cd, or Pb; R = Sc, Y, or La-Lu). These phases have superionic fluorine conductivity due to the anion sublattice disorder. The ionic conductivity of crystals of both structure types has been studied and the limits of its change with composition and temperature are determined. Nonstoichiometric fluorides are used as solid electrolytes in chemical sensors, fluorine sources, and batteries. The prospects of the use of fluorine-ion conductors in solid-state electrochemical devices, principles of their operation, and the problems of optimization of their composition are discussed.

Optimized Li-Ion Electrolytes Containing Triphenyl Phosphate as a Flame-Retardant Additive

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Bugga, Ratnakumar V.; Prakash, G. K. Surya; Krause, Frederick C.

2011-01-01

A number of future NASA missions involving the exploration of the Moon and Mars will be human-rated and thus require high-specific-energy rechargeable batteries that possess enhanced safety characteristics. Given that Li-ion technology is the most viable rechargeable energy storage device for near-term applications, effort has been devoted to improving the safety characteristics of this system. There is also a strong desire to develop Li-ion batteries with improved safety characteristics for terrestrial applications, most notably for hybrid electric vehicle (HEV) and plug-in hybrid electric vehicle (PHEV) automotive applications. Therefore, extensive effort has been devoted recently to developing non-flammable electrolytes to reduce the flammability of the cells/battery. A number of electrolyte formulations have been developed, including systems that (1) incorporate greater concentrations of the flame-retardant additive (FRA); (2) use di-2,2,2-trifluoroethyl carbonate (DTFEC) as a co-solvent; (3) use 2,2,2- trifluoroethyl methyl carbonate (TFEMC); (4) use mono-fluoroethylene carbonate (FEC) as a co-solvent and/or a replacement for ethylene carbonate in the electrolyte mixture; and (5) utilize vinylene carbonate as a "SEI promoting" electrolyte additive, to build on the favorable results previously obtained. To extend the family of electrolytes developed under previous work, a number of additional electrolyte formulations containing FRAs, most notably triphenyl phosphate (TPP), were investigated and demonstrated in experimental MCMB (mesocarbon micro beads) carbon- LiNi(0.8)Co(0.2)O2 cells. The use of higher concentrations of the FRA is known to reduce the flammability of the electrolyte solution, thus, a concentration range was investigated (i.e., 5 to 20 percent by volume). The desired concentration of the FRA is the highest amount tolerable without adversely affecting the performance in terms of reversibility, ability to operate over a wide temperature range, and the discharge rate capability. The use of fluorinated carbonates, much in the same manner as the incorporation of fluorinated ester-based solvents, was employed to reduce the inherent flammability of mixtures. Thus, electrolyte formulations that embody both approaches are anticipated to have much lower flammability, resulting in enhanced safety.

Biocompatible silk-conducting polymer composite trilayer actuators

NASA Astrophysics Data System (ADS)

Fengel, Carly V.; Bradshaw, Nathan P.; Severt, Sean Y.; Murphy, Amanda R.; Leger, Janelle M.

2017-05-01

Biocompatible materials capable of controlled actuation are in high demand for use in biomedical applications such as dynamic tissue scaffolding, valves, and steerable surgical tools. Conducting polymer actuators are of interest because they operate in aqueous electrolytes at low voltages and can generate stresses similar to natural muscle. Recently, our group has demonstrated a composite material of silk and poly(pyrrole) (PPy) that is mechanically robust, made from biocompatible materials, and bends under an applied voltage when incorporated into a simple bilayer device architecture and actuated using a biologically relevant electrolyte. Here we present trilayer devices composed of two silk-PPy composite layers separated by an insulating silk layer. The trilayer architecture allows one side to expand while the other contracts, resulting in improved performance over bilayer devices. Specifically, this configuration shows a larger angle of deflection per volt applied than the analogous bilayer system, while maintaining a consistent current response throughout cycling. In addition, the overall motion of the trilayer devices is more symmetric than that of the bilayer analogs, allowing for fully reversible operation.

Effects of Propylene Carbonate Content in CsPF6-Containing Electrolytes on the Enhanced Performances of Graphite Electrode for Lithium-Ion Batteries

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

Zheng, Jianming; Yan, Pengfei; Cao, Ruiguo

2016-02-10

Cesium salt has been demonstrated as an efficient electrolyte additive in suppressing the lithium (Li) dendrite formation and directing the formation of an ultrathin and stable solid electrolyte interphase (SEI) even in propylene carbonate (PC)-ethylene carbonate (EC)-based electrolytes. Here, we further investigate the effect of PC content in the presence of CsPF6 additive (0.05 M) on the performances of graphite electrode in Li||graphite half cells and in graphite||LiNi0.80Co0.15Al0.05O2 (NCA) full cells. It is found that the performance of graphite electrode is also affected by PC content even though CsPF6 additive is present in the electrolytes. An optimal PC content ofmore » 20% by weight in the solvent mixtures is identified. The enhanced electrochemical performance of graphite electrode is attributed to the synergistic effects of the Cs+ additive and the PC solvent. The formation of a robust, ultrathin and compact SEI layer containing lithium-enriched species on the graphite electrode, directed by Cs+, effectively suppresses the PC co-intercalation and thus prevents the graphite exfoliation. This SEI layer is only permeable for de-solvated Li+ ions and allows fast Li+ ion transport through it, which therefore largely alleviates the Li dendrite formation on graphite electrode during lithiation even at high current densities. The presence of low-melting-point PC solvent also enables the sustainable operation of the graphite||NCA full cells under a wide spectrum of temperatures. The fundamental findings of this work shed light on the importance of manipulating/maintaining the electrode/electrolyte interphasial stability in a variety of energy storage devices.« less

Major intrinsic proteins in biomimetic membranes.

PubMed

Nielsen, Claus Hélix

2010-01-01

Biological membranes define the structural and functional boundaries in living cells and their organelles. The integrity of the cell depends on its ability to separate inside from outside and yet at the same time allow massive transport of matter in and out the cell. Nature has elegantly met this challenge by developing membranes in the form of lipid bilayers in which specialized transport proteins are incorporated. This raises the question: is it possible to mimic biological membranes and create a membrane based sensor and/or separation device? In the development of a biomimetic sensor/separation technology, a unique class of membrane transport proteins is especially interesting-the major intrinsic proteins (MIPs). Generally, MIPs conduct water molecules and selected solutes in and out of the cell while preventing the passage of other solutes, a property critical for the conservation of the cells internal pH and salt concentration. Also known as water channels or aquaporins they are highly efficient membrane pore proteins some of which are capable of transporting water at very high rates up to 10(9) molecules per second. Some MIPs transport other small, uncharged solutes, such as glycerol and other permeants such as carbon dioxide, nitric oxide, ammonia, hydrogen peroxide and the metalloids antimonite, arsenite, silicic and boric acid depending on the effective restriction mechanism of the protein. The flux properties of MIPs thus lead to the question ifMIPs can be used in separation devices or as sensor devices based on, e.g., the selective permeation of metalloids. In principle a MIP based membrane sensor/separation device requires the supporting biomimetic matrix to be virtually impermeable to anything but water or the solute in question. In practice, however, a biomimetic support matrix will generally have finite permeabilities to both electrolytes and non-electrolytes. The feasibility of a biomimetic MIP device thus depends on the relative transport contribution from both protein and biomimetic support matrix. Also the biomimetic matrix must be encapsulated in order to protect it and make it sufficiently stable in a final application. Here, I specifically discuss the feasibility of developing osmotic biomimetic MIP membranes, but the technical issues are of general concern in the design ofbiomimetic membranes capable of supporting selective transmembrane fluxes.

Miniaturized supercapacitors: key materials and structures towards autonomous and sustainable devices and systems.

PubMed

Soavi, Francesca; Bettini, Luca Giacomo; Piseri, Paolo; Milani, Paolo; Santoro, Carlo; Atanassov, Plamen; Arbizzani, Catia

2016-09-15

Supercapacitors (SCs) are playing a key role for the development of self-powered and self-sustaining integrated systems for different fields ranging from remote sensing, robotics and medical devices. SC miniaturization and integration into more complex systems that include energy harvesters and functional devices are valuable strategies that address system autonomy. Here, we discuss about novel SC fabrication and integration approaches. Specifically, we report about the results of interdisciplinary activities on the development of thin, flexible SCs by an additive technology based on Supersonic Cluster Beam Deposition (SCBD) to be implemented into supercapacitive electrolyte gated transistors and supercapacitive microbial fuel cells. Such systems integrate at materials level the specific functions of devices, like electric switch or energy harvesting with the reversible energy storage capability. These studies might open new frontiers for the development and application of new multifunction-energy storage elements.

On-chip collection of particles and cells by AC electroosmotic pumping and dielectrophoresis using asymmetric microelectrodes.

PubMed

Melvin, Elizabeth M; Moore, Brandon R; Gilchrist, Kristin H; Grego, Sonia; Velev, Orlin D

2011-09-01

The recent development of microfluidic "lab on a chip" devices requiring sample sizes <100 μL has given rise to the need to concentrate dilute samples and trap analytes, especially for surface-based detection techniques. We demonstrate a particle collection device capable of concentrating micron-sized particles in a predetermined area by combining AC electroosmosis (ACEO) and dielectrophoresis (DEP). The planar asymmetric electrode pattern uses ACEO pumping to induce equal, quadrilateral flow directed towards a stagnant region in the center of the device. A number of system parameters affecting particle collection efficiency were investigated including electrode and gap width, chamber height, applied potential and frequency, and number of repeating electrode pairs and electrode geometry. The robustness of the on-chip collection design was evaluated against varying electrolyte concentrations, particle types, and particle sizes. These devices are amenable to integration with a variety of detection techniques such as optical evanescent waveguide sensing.

Miniaturized supercapacitors: key materials and structures towards autonomous and sustainable devices and systems

NASA Astrophysics Data System (ADS)

Soavi, Francesca; Bettini, Luca Giacomo; Piseri, Paolo; Milani, Paolo; Santoro, Carlo; Atanassov, Plamen; Arbizzani, Catia

2016-09-01

Supercapacitors (SCs) are playing a key role for the development of self-powered and self-sustaining integrated systems for different fields ranging from remote sensing, robotics and medical devices. SC miniaturization and integration into more complex systems that include energy harvesters and functional devices are valuable strategies that address system autonomy. Here, we discuss about novel SC fabrication and integration approaches. Specifically, we report about the results of interdisciplinary activities on the development of thin, flexible SCs by an additive technology based on Supersonic Cluster Beam Deposition (SCBD) to be implemented into supercapacitive electrolyte gated transistors and supercapacitive microbial fuel cells. Such systems integrate at materials level the specific functions of devices, like electric switch or energy harvesting with the reversible energy storage capability. These studies might open new frontiers for the development and application of new multifunction-energy storage elements.

Computer-aided design and experimental investigation of a hydrodynamic device: the microwire electrode

PubMed

Fulian; Gooch; Fisher; Stevens; Compton

2000-08-01

The development and application of a new electrochemical device using a computer-aided design strategy is reported. This novel design is based on the flow of electrolyte solution past a microwire electrode situated centrally within a large duct. In the design stage, finite element simulations were employed to evaluate feasible working geometries and mass transport rates. The computer-optimized designs were then exploited to construct experimental devices. Steady-state voltammetric measurements were performed for a reversible one-electron-transfer reaction to establish the experimental relationship between electrolysis current and solution velocity. The experimental results are compared to those predicted numerically, and good agreement is found. The numerical studies are also used to establish an empirical relationship between the mass transport limited current and the volume flow rate, providing a simple and quantitative alternative for workers who would prefer to exploit this device without the need to develop the numerical aspects.

A sugar-template manufacturing method for microsystem ion-exchange membranes

NASA Astrophysics Data System (ADS)

Festarini, Rio V.; Pham, Minh-Hao; Liu, Xinyue; Barz, Dominik P. J.

2017-07-01

In this work, we report on a novel method for producing ion-exchange membranes that can be integrated directly into polydimethylsiloxane-based micro devices. Ionomers such as NafionTM, a copolymer with high conductivity and selectivity to small cations, are generally incompatible with common micro device materials due to the chemical inertness of the tetrafluoroethylene-based skeleton and the swelling in aqueous solutions. Hence, we introduce a microfabrication concept where we use consolidated sugar granules as a template to produce a porous polydimethylsiloxane scaffold. Ionomer and scaffold are combined to a composite membrane where the cohesion of these incompatible materials is of rather mechanical nature; i.e. the ionomer is physically entrapped in the scaffold. Electrochemical impedance spectroscopy measurements reveal the excellent membrane conductivity for the upper electrolyte concentrations tested in this work.

Embedding solar cell materials with on-board integrated energy storage for load-leveling and dark power delivery (Presentation Recording)

NASA Astrophysics Data System (ADS)

Pint, Cary L.; Westover, Andrew S.; Cohn, Adam P.; Erwin, William R.; Share, Keith; Metke, Thomas; Bardhan, Rizia

2015-10-01

This work will discuss our recent advances focused on integrating high power energy storage directly into the native materials of both conventional photovoltaics (PV) and dye-sensitized solar cells (DSSCs). In the first case (PV), we demonstrate the ability to etch high surface-area porous silicon charge storage interfaces directly into the backside of a conventional polycrystalline silicon photovoltaic device exhibiting over 14% efficiency. These high surface area materials are then coupled with solid-state ionic liquid-polymer electrolytes to produce solid-state fully integrated devices where the PV device can directly inject charge into an on-board supercapacitor that can be separately discharged under dark conditions with a Coulombic efficiency of 84%. In a similar manner, we further demonstrate that surface engineered silicon materials can be utilized to replace Pt counterelectrodes in conventional DSSC energy conversion devices. As the silicon counterelectrodes rely strictly on surface Faradaic chemical reactions with the electrolyte on one side of the wafer electrode, we demonstrate double-sided processing of electrodes that enables dual-function of the material for simultaneous energy storage and conversion, each on opposing sides. In both of these devices, we demonstrate the ability to produce an all-silicon coupled energy conversion and storage system through the common ability to convert unused silicon in solar cells into high power silicon-based supercapacitors. Beyond the proof-of-concept design and performance of this integrated solar-storage system, this talk will conclude with a brief discussion of the hurdles and challenges that we envision for this emerging area both from a fundamental and technological viewpoint.

Biochemical testing in a laboratory tent and semi-intensive care of Ebola patients on-site in a remote part of Guinea: a paradigm shift based on a bleach-sensitive point-of-care device.

PubMed

Irenge, Leonid M; Dindart, Jean-Michel; Gala, Jean-Luc

2017-10-26

During the West Africa Ebola virus disease (EVD) outbreak, a Belgian laboratory was deployed for supporting the Ebola treatment unit (ETU) of N'Zerekore, Guinea. Besides diagnosis of EVD and malaria, biochemical parameters were tested and used to guide supportive treatment of EVD. To preserve analytes stability, lithium-heparin blood samples were analyzed using the i-STAT® point-of-care testing (POCT) handheld device without the viral inactivation step. To mitigate the risk of Ebola virus transmission, assays were performed inside a portable glovebox with strict biosafety procedures. Providing the medical staff with real-time biochemical data modified their therapeutic attitude, shifting from empiric to a semi-intensive laboratory-guided treatment of hydro-electrolytic disturbances, metabolic acidosis and/or impaired kidney function. As illustrated with representative EVD cases (n=8), optimized supportive treatment with intravenous fluid therapy and electrolyte replacement often helped correct these abnormalities. However, the harsh operating conditions, especially the use of bleach decontamination inside the glovebox, caused several technical failures and the final breakdown of the POCT device. POCT availability resulted in a paradigm shift in laboratory practice and care delivery at the N'Zerekore ETU. We conclude that there is urgent need for novel well-designed and validated POCT devices usable by non-expert operators in high ambient temperature and limited space. These devices should withstand regular and thorough decontamination by the personnel working on-site with life-threatening pathogens and be compatible with high biosafety level procedures. Such specific users' requirements need a European validation and standardization process of proposed solutions led by the EU Standardization Committee (CEN).

Electra-optical device including a nitrogen containing electrolyte

DOEpatents

Bates, J.B.; Dudney, N.J.; Gruzalski, G.R.; Luck, C.F.

1995-10-03

Described is a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode. Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between {minus}15 C and 150 C.

Next-Generation Electrochemical Energy Materials for Intermediate Temperature Molten Oxide Fuel Cells and Ion Transport Molten Oxide Membranes.

PubMed

Belousov, Valery V

2017-02-21

High temperature electrochemical devices such as solid oxide fuel cells (SOFCs) and oxygen separators based on ceramic materials are used for efficient energy conversion. These devices generally operate in the temperature range of 800-1000 °C. The high operating temperatures lead to accelerated degradation of the SOFC and oxygen separator materials. To solve this problem, the operating temperatures of these electrochemical devices must be lowered. However, lowering the temperature is accompanied by decreasing the ionic conductivity of fuel cell electrolyte and oxygen separator membrane. Therefore, there is a need to search for alternative electrolyte and membrane materials that have high ionic conductivity at lower temperatures. A great many opportunities exist for molten oxides as electrochemical energy materials. Because of their unique electrochemical properties, the molten oxide innovations can offer significant benefits for improving energy efficiency. In particular, the newly developed electrochemical molten oxide materials show high ionic conductivities at intermediate temperatures (600-800 °C) and could be used in molten oxide fuel cells (MOFCs) and molten oxide membranes (MOMs). The molten oxide materials containing both solid grains and liquid channels at the grain boundaries have advantages compared to the ceramic materials. For example, the molten oxide materials are ductile, which solves a problem of thermal incompatibility (difference in coefficient of thermal expansion, CTE). Besides, the outstanding oxygen selectivity of MOM materials allows us to separate ultrahigh purity oxygen from air. For their part, the MOFC electrolytes show the highest ionic conductivity at intermediate temperatures. To evaluate the potential of molten oxide materials for technological applications, the relationship between the microstructure of these materials and their transport and mechanical properties must be revealed. This Account summarizes the latest results on oxygen ion transport in potential MOM materials and MOFC electrolytes. In addition, we consider the rapid oxygen transport in a molten oxide scale formed on a metal surface during catastrophic oxidation and show that the same transport could be used beneficially in MOMs and MOFCs. A polymer model explaining the oxygen transport in molten oxides is also considered. Understanding the oxygen transport mechanisms in oxide melts is important for the development of new generation energy materials, which will contribute to more efficient operation of electrochemical devices at intermediate temperatures. Here we highlight the progress made in developing this understanding. We also show the latest advances made in search of alternative molten oxide materials having high mixed ion electronic and ionic conductivities for use in MOMs and MOFCs, respectively. Prospects for further research are presented.

Internal passivation of Al-based microchannel devices by electrochemical anodization

NASA Astrophysics Data System (ADS)

Hymel, Paul J.; Guan, D. S.; Mu, Yang; Meng, W. J.; Meng, Andrew C.

2015-02-01

Metal-based microchannel devices have wide-ranging applications. We report here a method to electrochemically anodize the internal surfaces of Al microchannels, with the purpose of forming a uniform and dense anodic aluminum oxide (AAO) layer on microchannel internal surfaces for chemical passivation and corrosion resistance. A pulsed electrolyte flow was utilized to emulate conventional anodization processes while replenishing depleted ionic species within Al microtubes and microchannels. After anodization, the AAO film was sealed in hot water to close the nanopores. Focused ion beam (FIB) sectioning, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were utilized to characterize the AAO morphology and composition. Potentiodynamic polarization corrosion testing of anodized Al microtube half-sections in a NaCl solution showed an order of magnitude decrease in anodic corrosion current when compared to an unanodized tube. The surface passivation process was repeated for Al-based microchannel heat exchangers. A corrosion testing method based on the anodization process showed higher resistance to ion transport through the anodized specimens than unanodized specimens, thus verifying the internal anodization and sealing process as a viable method for surface passivation of Al microchannel devices.

Fabrication of a stretchable solid-state micro-supercapacitor array.

PubMed

Kim, Daeil; Shin, Gunchul; Kang, Yu Jin; Kim, Woong; Ha, Jeong Sook

2013-09-24

We fabricated a stretchable micro-supercapacitor array with planar SWCNT electrodes and an ionic liquid-based triblock copolymer electrolyte. The mechanical stability of the entire supercapacitor array upon stretching was obtained by adopting strategic design concepts. First, the narrow and long serpentine metallic interconnections were encapsulated with polyimide thin film to ensure that they were within the mechanical neutral plane. Second, an array of two-dimensional planar micro-supercapacitor with SWCNT electrodes and an ion-gel-type electrolyte was made to achieve all-solid-state energy storage devices. The formed micro-supercapacitor array showed excellent performances which were stable over stretching up to 30% without any noticeable degradation. This work shows the strong potential of a stretchable micro-supercapacitor array in applications such as wearable computers, power dressing, electronic newspapers, paper-like mobile phones, and other easily collapsible gadgets.

In situ liquid water visualization in polymer electrolyte membrane fuel cells with high resolution synchrotron x-ray radiography

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

Chevalier, S.; Banerjee, R.; Lee, J.

In this work, we investigated the dominating properties of the porous materials that impact water dynamics in a polymer electrolyte membrane fuel cell (PEMFC). Visualizations of liquid water in an operating PEMFC were performed at the Canadian Light Source. A miniature fuel cell was specifically designed for X-ray imaging investigations, and an in-house image processing algorithm based on the Beer-Lambert law was developed to extract quantities of liquid water thicknesses (cm) from raw X-ray radiographs. The X-ray attenuation coefficient of water at 24 keV was measured with a calibration device to ensure accurate measurements of the liquid water thicknesses. Frommore » this experiment, the through plane distribution of the liquid water in the fuel cell was obtained.« less

Lithium/water battery with lithium ion conducting glass-ceramics electrolyte

NASA Astrophysics Data System (ADS)

Katoh, Takashi; Inda, Yasushi; Nakajima, Kousuke; Ye, Rongbin; Baba, Mamoru

Lithium/water batteries have attracted considerable attention as high power supply devices because they use high energy density lithium metal as an anode and water as a cathode. In this study, we investigate the use of lithium/water batteries that use a glass-ceramics plate as an electrolyte. A lithium ion conducting glass-ceramics plate has no through-holes and does not exhibit moisture permeation. Such a plate has stable ionic conductivity in water. Lithium/water batteries that used a glass-ceramics plate as an electrolyte had a long and stable discharge for 50 days at room temperature when the lithium metal was prevented from coming into contact with water. Lithium/seawater batteries using a glass-ceramics plate as an electrolyte also operated well in the 10-70 °C temperature range.

High Electrocatalytic Activity of Vertically Aligned Single-Walled Carbon Nanotubes towards Sulfide Redox Shuttles.

PubMed

Hao, Feng; Dong, Pei; Zhang, Jing; Zhang, Yongchang; Loya, Phillip E; Hauge, Robert H; Li, Jianbao; Lou, Jun; Lin, Hong

2012-01-01

Vertically aligned single-walled carbon nanotubes (VASWCNTs) have been successfully transferred onto transparent conducting oxide glass and implemented as efficient low-cost, platinum-free counter electrode in sulfide -mediated dye-sensitized solar cells (DSCs), featuring notably improved electrocatalytic activity toward thiolate/disulfide redox shuttle over conventional Pt counter electrodes. Impressively, device with VASWCNTs counter electrode demonstrates a high fill factor of 0.68 and power conversion efficiency up to 5.25%, which is significantly higher than 0.56 and 3.49% for that with a conventional Pt electrode. Moreover, VASWCNTs counter electrode produces a charge transfer resistance of only 21.22 Ω towards aqueous polysulfide electrolyte commonly applied in quantum dots-sensitized solar cells (QDSCs), which is several orders of magnitude lower than that of a typical Pt electrode. Therefore, VASWCNTs counter electrodes are believed to be a versatile candidate for further improvement of the power conversion efficiency of other iodine-free redox couple based DSCs and polysulfide electrolyte based QDSCs.

Aqueous based asymmetrical-bipolar electrochemical capacitor with a 2.4 V operating voltage

NASA Astrophysics Data System (ADS)

Wu, Haoran; Lian, Keryn

2018-02-01

A novel asymmetrical-bipolar electrochemical capacitor system leveraging the contributions of a Zn-CNT asymmetrical electrode and a KOH-H2SO4 dual-pH electrolyte was developed. The positive and negative electrodes operated in electrolytes with different pH, exploiting the maximum potential of both electrodes, which led to a cell voltage of 2.4 V. The potential tracking of both electrodes revealed that the Zn negative electrode could maintain a potential at -1.2 V, while the CNT positive electrode can be charged to +1.2 V without significant irreversible reactions. A bipolar ion exchange membrane has effectively separated the acid and alkaline from neutralization, which resulted in stable performance of the device with capacitance retention of 94% and coulombic efficiency of 99% over 10,000 cycles. This asymmetrical-bipolar design overcomes the thermodynamic limit of water decomposition, opening a new avenue towards high energy and high power density aqueous-based ECs.

Highly Efficient Plastic Crystal Ionic Conductors for Solid-state Dye-sensitized Solar Cells

PubMed Central

Hwang, Daesub; Kim, Dong Young; Jo, Seong Mu; Armel, Vanessa; MacFarlane, Douglas R.; Kim, Dongho; Jang, Sung-Yeon

2013-01-01

We have developed highly efficient, ambient temperature, solid-state ionic conductors (SSICs) for dye-sensitized solar cells (DSSCs) by doping a molecular plastic crystal, succinonitrile (SN), with trialkyl-substituted imidazolium iodide salts. High performance SSICs with enhanced ionic conductivity (2–4 mScm−1) were obtained. High performance solid-state DSSCs with power conversion efficiency of 7.8% were fabricated using our SSICs combined with unique hierarchically nanostructured TiO2 sphere (TiO2-SP) photoelectrodes; these electrodes have significant macroporosity, which assists penetration of the solid electrolyte into the electrode. The performance of our solid-state DSSCs is, to the best of our knowledge, the highest reported thus far for cells using plastic crystal-based SSICs, and is comparable to that of the state-of-the-art DSSCs which use ionic liquid type electrolytes. This report provides a logical strategy for the development of efficient plastic crystal-based SSICs for DSSCs and other electrochemical devices. PMID:24343425

Charging the quantum capacitance of graphene with a single biological ion channel.

PubMed

Wang, Yung Yu; Pham, Ted D; Zand, Katayoun; Li, Jinfeng; Burke, Peter J

2014-05-27

The interaction of cell and organelle membranes (lipid bilayers) with nanoelectronics can enable new technologies to sense and measure electrophysiology in qualitatively new ways. To date, a variety of sensing devices have been demonstrated to measure membrane currents through macroscopic numbers of ion channels. However, nanoelectronic based sensing of single ion channel currents has been a challenge. Here, we report graphene-based field-effect transistors combined with supported lipid bilayers as a platform for measuring, for the first time, individual ion channel activity. We show that the supported lipid bilayers uniformly coat the single layer graphene surface, acting as a biomimetic barrier that insulates (both electrically and chemically) the graphene from the electrolyte environment. Upon introduction of pore-forming membrane proteins such as alamethicin and gramicidin A, current pulses are observed through the lipid bilayers from the graphene to the electrolyte, which charge the quantum capacitance of the graphene. This approach combines nanotechnology with electrophysiology to demonstrate qualitatively new ways of measuring ion channel currents.

High-performance aqueous asymmetric supercapacitor based on K0.3WO3 nanorods and nitrogen-doped porous carbon

NASA Astrophysics Data System (ADS)

Ma, Guofu; Zhang, Zhiguo; Sun, Kanjun; Feng, Enke; Peng, Hui; Zhou, Xiaozhong; Lei, Ziqiang

2016-10-01

A novel asymmetric supercapacitor device for energy storage is fabricated using K0.3WO3 nanorods as negative electrode and nitrogen-doped porous carbon (CBC-1) based on agricultural wastes corn bract as positive electrode. The K0.3WO3 nanorods are composed of some thinner needle-shaped nanorods which are parallel to each other, and the CBC-1 reveals rough surface of coral-like frameworks with abundant nanopores. The structures can provide high surface area, low diffusion paths and intercalation/de-intercalation of electrolyte ions between the electrode/electrolyte interfaces. Thus, the asymmetric supercapacitor exhibits high energy density about 26.3 Wh kg-1 at power density of 404.2 W kg-1 in the wide voltage region of 0-1.6 V, as well as a good electrochemical stability (80% capacitance retention after 1000 cycles). Such outstanding electrochemical behaviors imply the CBC-1//K0.3WO3 asymmetric supercapacitor is a promising practical energy-storage system.

Efficient and Stable Silicon Microwire Photocathodes with a Nickel Silicide Interlayer for Operation in Strongly Alkaline Solutions.

PubMed

Vijselaar, Wouter; Tiggelaar, Roald M; Gardeniers, Han; Huskens, Jurriaan

2018-05-11

Most photoanodes commonly applied in solar fuel research (e.g., of Fe 2 O 3 , BiVO 4 , TiO 2 , or WO 3 ) are only active and stable in alkaline electrolytes. Silicon (Si)-based photocathodes on the other hand are mainly studied under acidic conditions due to their instability in alkaline electrolytes. Here, we show that the in-diffusion of nickel into a 3D Si structure, upon thermal annealing, yields a thin (sub-100 nm), defect-free nickel silicide (NiSi) layer. This has allowed us to design and fabricate a Si microwire photocathode with a NiSi interlayer between the catalyst and the Si microwires. Upon electrodeposition of the catalyst (here, nickel molybdenum) on top of the NiSi layer, an efficient, Si-based photocathode was obtained that is stable in strongly alkaline solutions (1 M KOH). The best-performing, all-earth-abundant microwire array devices exhibited, under AM 1.5G simulated solar illumination, an ideal regenerative cell efficiency of 10.1%.

Charging the Quantum Capacitance of Graphene with a Single Biological Ion Channel

PubMed Central

2015-01-01

The interaction of cell and organelle membranes (lipid bilayers) with nanoelectronics can enable new technologies to sense and measure electrophysiology in qualitatively new ways. To date, a variety of sensing devices have been demonstrated to measure membrane currents through macroscopic numbers of ion channels. However, nanoelectronic based sensing of single ion channel currents has been a challenge. Here, we report graphene-based field-effect transistors combined with supported lipid bilayers as a platform for measuring, for the first time, individual ion channel activity. We show that the supported lipid bilayers uniformly coat the single layer graphene surface, acting as a biomimetic barrier that insulates (both electrically and chemically) the graphene from the electrolyte environment. Upon introduction of pore-forming membrane proteins such as alamethicin and gramicidin A, current pulses are observed through the lipid bilayers from the graphene to the electrolyte, which charge the quantum capacitance of the graphene. This approach combines nanotechnology with electrophysiology to demonstrate qualitatively new ways of measuring ion channel currents. PMID:24754625

Polymer electrolytes based on sulfonated polysulfone for direct methanol fuel cells

NASA Astrophysics Data System (ADS)

Lufrano, F.; Baglio, V.; Staiti, P.; Arico', A. S.; Antonucci, V.

This paper reports the development and characterization of sulfonated polysulfone (SPSf) polymer electrolytes for direct methanol fuel cells. The synthesis of sulfonated polysulfone was performed by a post sulfonation method using trimethyl silyl chlorosulfonate as a mild sulfonating agent. Bare polysulfone membranes were prepared with two different sulfonation levels (60%, SPSf-60 and 70%, SPSf-70), whereas, a composite membrane of SPSf-60 was prepared with 5 wt% silica filler. These membranes were investigated in direct methanol fuel cells (DMFCs) operating at low (30-40 °C) and high temperatures (100-120 °C). DMFC power densities were about 140 mW cm -2 at 100 °C with the bare SPSf-60 membrane and 180 mW cm -2 at 120 °C with the SPSf-60-SiO2 composite membrane. The best performance achieved at ambient temperature using a membrane with high degree of sulfonation (70%, SPSf-70) was 20 mW cm -2 at atmospheric pressure. This makes the polysulfone-based DMFC suitable for application in portable devices.

Light-addressable electrodeposition of cell-encapsulated alginate hydrogels for a cellular microarray using a digital micromirror device

PubMed Central

Huang, Shih-Hao; Hsueh, Hui-Jung; Jiang, Yeu-Long

2011-01-01

This paper describes a light-addressable electrolytic system used to perform an electrodeposition of calcium alginate hydrogels using a digital micromirror device (DMD). In this system, a patterned light illumination is projected onto a photoconductive substrate serving as a photo-anode to electrolytically produce protons, which can lead to a decreased pH gradient. The low pH generated at the anode can locally release calcium ions from insoluble calcium carbonate (CaCO3) to cause gelation of calcium alginate through sol-gel transition. By controlling the illumination pattern on the DMD, a light-addressable electrodeposition of calcium alginate hydrogels with different shapes and sizes, as well as multiplexed micropatterning was performed. The effects of the concentration of the alginate and CaCO3 solutions on the dimensional resolution of alginate hydrogel formation were experimentally examined. A 3 × 3 array of cell-encapsulated alginate hydrogels was also successfully demonstrated through light-addressable electrodeposition. Our proposed method provides a programmable method for the spatiotemporally controllable assembly of cell populations into cellular microarrays and could have a wide range of biological applications in cell-based biosensing, toxicology, and drug discovery. PMID:22685500

Light-addressable electrodeposition of cell-encapsulated alginate hydrogels for a cellular microarray using a digital micromirror device.

PubMed

Huang, Shih-Hao; Hsueh, Hui-Jung; Jiang, Yeu-Long

2011-09-01

This paper describes a light-addressable electrolytic system used to perform an electrodeposition of calcium alginate hydrogels using a digital micromirror device (DMD). In this system, a patterned light illumination is projected onto a photoconductive substrate serving as a photo-anode to electrolytically produce protons, which can lead to a decreased pH gradient. The low pH generated at the anode can locally release calcium ions from insoluble calcium carbonate (CaCO(3)) to cause gelation of calcium alginate through sol-gel transition. By controlling the illumination pattern on the DMD, a light-addressable electrodeposition of calcium alginate hydrogels with different shapes and sizes, as well as multiplexed micropatterning was performed. The effects of the concentration of the alginate and CaCO(3) solutions on the dimensional resolution of alginate hydrogel formation were experimentally examined. A 3 × 3 array of cell-encapsulated alginate hydrogels was also successfully demonstrated through light-addressable electrodeposition. Our proposed method provides a programmable method for the spatiotemporally controllable assembly of cell populations into cellular microarrays and could have a wide range of biological applications in cell-based biosensing, toxicology, and drug discovery.

Functionalized vertically aligned ZnO nanorods for application in electrolyte-insulator-semiconductor based pH sensors and label-free immuno-sensors

NASA Astrophysics Data System (ADS)

Kumar, Narendra; Senapati, Sujata; Kumar, Satyendra; Kumar, Jitendra; Panda, Siddhartha

2016-04-01

Vertically aligned ZnO nanorods were grown on a SiO2/Si surface by optimization of the temperature and atmosphere for annealing of the seed. The seed layer annealed at 500 °C in vacuum provided well separated and uniform seeds which also provided the best condition to get densely packed, uniformly distributed, and vertically aligned nanorods. These nanorods grown on the substrates were used to fabricate electrolyte-insulator-semiconductor (EIS) devices for pH sensing. Etching of ZnO at acidic pH prevents the direct use of nanorods for pH sensing. Therefore, the nanorods functionalised with 3-aminopropyltriethoxysilane (APTES) were utilized for pH sensing and showed the pH sensitivity of 50.1 mV/pH. APTES is also known to be used as a linker to immobilize biomolecules (such as antibodies). The EIS device with APTES functionalized nanorods was used for the label free detection of prostate-specific antigen (PSA). Finally, voltage shifts of 23 mV and 35 mV were observed with PSA concentrations of 1 ng/ml and 100 ng/ml, respectively.

Graphene based nanocomposite hybrid electrodes for supercapacitors

NASA Astrophysics Data System (ADS)

Aphale, Ashish N.

There is an unmet need to develop high performance energy storage systems (ESS), capable of storing energy from both renewable and non-renewable sources to meet the current energy crisis and depletion of non-renewable sources. Amongst many available ESS, supercapacitors (ECs) are the most promising because they exhibit a high charge/discharge rate and power density, along with a long cycle life. The possibility of exploring the use of atomically thin carbon allotropes like graphene, carbon nanotubes (CNTs) and electrically conducting polymers (ECPs) such as polypyrrole (PPy) has been studied as a high performance conducting electrodes in supercapacitor application. A novel templated sustainable nanocomposite electrode has been fabricated using cellulose extracted from Cladophora c. aegagropila algae as component of the assembled supercapacitor device which later has been transitioned to a unique template-less freestanding nanocomposite supercapacitor electrode. The specific capacitance of polypyrrole-graphene-cellulose nanocomposite as calculated from cyclic voltammetry curve is 91.5 F g -1 at the scan rate 50 m Vs-1 in the presence of 1M NaCl electrolyte. The open circuit voltage of the device with polypyrrole -graphene-cellulose electrode was found to be around 225 m V and that of the polypyrrole -cellulose device is only 53 m V without the presence of graphene in the nanocomposite electrode. Understanding the fundamentals by fabricating template nanocomposite electrode, it led to fabricate a unique nanocomposite template-less freestanding film which comprises of polypyrrole-graphene-CNT hybrid. Various experiments have been performed using different electrolytes such ascorbic acid, sodium sulfate and sulfuric acid in different scan rates. The specific capacitance of polypyrrole-graphene-CNT nanocomposite with 0.1 wt% of graphene-CNT, as calculated from cyclic voltammetry curve is 450 F g-1 at the scan rate 5 m V s-1. For the first time a nanofibrous membrane has been developed as a separator which acts as an electrolyte reservoir and ionic diffusion membrane. The performance of the fabricated supercapacitor device has been analyzed using a multimeter and compared with a conventional alkaline (1.5 V) battery. Lighting up of 2.2 V light emitting diode has been demonstrated using the fabricated supercapacitor.

Electrochemical behavior of platinum nanoparticles on a carbon xerogel support modified with a [(trifluoromethyl)-benzenesulfonyl]imide electrolyte.

PubMed

Liu, Bing; Mei, Hua; DesMarteau, Darryl; Creager, Stephen E

2014-12-11

A monoprotic [(trifluoromethyl)benzenesulfonyl]imide (SI) superacid electrolyte was used to covalently modify a mesoporous carbon xerogel (CX) support via reaction of the corresponding trifluoromethyl aryl sulfonimide diazonium zwitterion with the carbon surface. Electrolyte attachment was demonstrated by elemental analysis, acid-base titration, and thermogravimetric analysis. The ion-exchange capacity of the fluoroalkyl-aryl-sulfonimide-grafted carbon xerogel (SI-CX) was ∼0.18 mequiv g(-1), as indicated by acid-base titration. Platinum nanoparticles were deposited onto the SI-grafted carbon xerogel samples by the impregnation and reduction method, and these materials were employed to fabricate polyelectrolyte membrane fuel-cell (PEMFC) electrodes by the decal transfer method. The SI-grafted carbon-xerogel-supported platinum (Pt/SI-CX) was characterized by X-ray diffraction and transmission electron microscopy to determine platinum nanoparticle size and distribution, and the findings are compared with CX-supported platinum catalyst without the grafted SI electrolyte (Pt/CX). Platinum nanoparticle sizes are consistently larger on Pt/SI-CX than on Pt/CX. The electrochemically active surface area (ESA) of platinum catalyst on the Pt/SI-CX and Pt/CX samples was measured with ex situ cyclic voltammetry (CV) using both hydrogen adsorption/desorption and carbon monoxide stripping methods and by in situ CV within membrane electrode assemblies (MEAs). The ESA values for Pt/SI-CX are consistently lower than those for Pt/CX. Some possible reasons for the behavior of samples with and without grafted SI layers and implications for the possible use of SI-grafted carbon layers in PEMFC devices are discussed.

A urea biosensor based on pH-sensitive Sm2TiO5 electrolyte-insulator-semiconductor.

PubMed

Pan, Tung-Ming; Huang, Ming-De; Lin, Wan-Ying; Wu, Min-Hsien

2010-06-11

A urea biosensor based on pH-sensitive Sm(2)TiO(5) electrolyte-insulator-semiconductor (EIS) has been described. We used X-ray diffraction, Auger electron spectroscopy, and atomic force microscopy to investigate the structural and morphological features of high-k Sm(2)TiO(5) sensing membranes that had been subjected to annealing at different temperatures. The EIS device incorporating a high-k Sm(2)TiO(5) sensing film that had been annealed at 900 degrees C exhibited good sensing characteristics, including a high sensitivity of 60.5 mV/pH (in solutions from pH 2 to 12), a small hysteresis voltage of 2.72 mV (in the pH loop 7-->4-->7-->10-->7), and a low drift rate of 1.15 mV h(-1) (in the buffer solution at pH 7). The Sm(2)TiO(5) EIS device also showed a high selective response towards H(+). This improvement can be attributed to the small number of crystal defects and the large surface roughness. In addition, the urea biosensor based on pH-sensitive EIS incorporating a Sm(2)TiO(5) sensing membrane annealed at 900 degrees C allowed the potentiometric analysis of urea, at concentrations ranging from 0.1 to 32 mM, with a sensitivity of 72.85 mV/purea. Copyright 2010 Elsevier B.V. All rights reserved.

Increased fracture depth range in controlled spalling of (100)-oriented germanium via electroplating

DOE PAGES

Crouse, Dustin; Simon, John; Schulte, Kevin L.; ...

2018-01-31

Controlled spalling in (100)-oriented germanium using a nickel stressor layer shows promise for semiconductor device exfoliation and kerfless wafering. Demonstrated spall depths of 7-60 um using DC sputtering to deposit the stressor layer are appropriate for the latter application but spall depths < 5 um may be required to minimize waste for device applications. This work investigates the effect of tuning both electroplating current density and electrolyte chemistry on the residual stress in the nickel and on the achievable spall depth range for the Ni/Ge system as a lower-cost, higher-throughput alternative to sputtering. By tuning current density and electrolyte phosphorousmore » concentration, it is shown that electroplating can successfully span the same range of spalled thicknesses as has previously been demonstrated by sputtering and can reach sufficiently high stresses to enter a regime of thickness (<7 um) appropriate to minimize substrate consumption for device applications.« less

Increased fracture depth range in controlled spalling of (100)-oriented germanium via electroplating

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

Crouse, Dustin; Simon, John; Schulte, Kevin L.

Controlled spalling in (100)-oriented germanium using a nickel stressor layer shows promise for semiconductor device exfoliation and kerfless wafering. Demonstrated spall depths of 7-60 um using DC sputtering to deposit the stressor layer are appropriate for the latter application but spall depths < 5 um may be required to minimize waste for device applications. This work investigates the effect of tuning both electroplating current density and electrolyte chemistry on the residual stress in the nickel and on the achievable spall depth range for the Ni/Ge system as a lower-cost, higher-throughput alternative to sputtering. By tuning current density and electrolyte phosphorousmore » concentration, it is shown that electroplating can successfully span the same range of spalled thicknesses as has previously been demonstrated by sputtering and can reach sufficiently high stresses to enter a regime of thickness (<7 um) appropriate to minimize substrate consumption for device applications.« less

Anti-perovskite solid electrolyte compositions

DOEpatents

Zhao, Yusheng; Daemen, Luc Louis

2015-12-26

Solid electrolyte antiperovskite compositions for batteries, capacitors, and other electrochemical devices have chemical formula Li.sub.3OA, Li.sub.(3-x)M.sub.x/2OA, Li.sub.(3-x)N.sub.x/3OA, or LiCOX.sub.zY.sub.(1-z), wherein M and N are divalent and trivalent metals respectively and wherein A is a halide or mixture of halides, and X and Y are halides.

The Role of Dissolved Gas in Ionic Liquid Electrolytes for Secondary Lithium Metal Batteries

DTIC Science & Technology

2013-01-07

devices use lithium-ion batteries comprised of a graphite anode and metal oxide cathode . Lithium, being the third-lightest element, is already synonymous...support shuttling lithium ions (battery cycling) such as the separator, electrolyte, and cathode and anode superstructures contribute most of the...ability of electro-deposit lithium non-dendritically. When lithium is electrodeposited , as during battery charging, it tends to form needle-like

Li-Ion Electrolytes with Improved Safety and Tolerance to High-Voltage Systems

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Bugga, Ratnakumar V.; Prakash, Surya; Krause, Frederick C.

2013-01-01

Given that lithium-ion (Li-ion) technology is the most viable rechargeable energy storage device for near-term applications, effort has been devoted to improving the safety characteristics of this system. Therefore, extensive effort has been devoted to developing nonflammable electrolytes to reduce the flammability of the cells/battery. A number of promising electrolytes have been developed incorporating flame-retardant additives, and have been shown to have good performance in a number of systems. However, these electrolyte formulations did not perform well when utilizing carbonaceous anodes with the high-voltage materials. Thus, further development was required to improve the compatibility. A number of Li-ion battery electrolyte formulations containing a flame-retardant additive [i.e., triphenyl phosphate (TPP)] were developed and demonstrated in high-voltage systems. These electrolytes include: (1) formulations that incorporate varying concentrations of the flame-retardant additive (from 5 to 15%), (2) the use of mono-fluoroethylene carbonate (FEC) as a co-solvent, and (3) the use of LiBOB as an electrolyte additive intended to improve the compatibility with high-voltage systems. Thus, improved safety has been provided without loss of performance in the high-voltage, high-energy system.

A novel quasi-solid state electrolyte with highly effective polysulfide diffusion inhibition for lithium-sulfur batteries

PubMed Central

Zhong, Hai; Wang, Chunhua; Xu, Zhibin; Ding, Fei; Liu, Xinjiang

2016-01-01

Polymer solid state electrolytes are actively sought for their potential application in energy storage devices, particularly lithium metal rechargeable batteries. Herein, we report a polymer with high concentration salts as a quasi-solid state electrolyte used for lithium-sulfur cells, which shows an ionic conductivity of 1.6 mS cm−1 at room temperature. The cycling performance of Li-S battery with this electrolyte shows a long cycle life (300 cycles) and high coulombic efficiency (>98%), without any consuming additives in the electrolyte. Moreover, it also shows a remarkably decreased self-discharge (only 0.2%) after storage for two weeks at room temperature. The reason can be attributed to that the electrolyte can suppress polysulfide anions diffusion, due to the high ratio oxygen atoms with negative charges which induce an electrical repulsion to the polysulfide anions, and their relatively long chains which can provide additional steric hindrance. Thus, the polysulfide anions can be located around carbon particles, which result in remarkably improved overall electrochemical performance, and also the electrolyte have a function of suppress the formation of lithium dendrites on the lithium anode surface. PMID:27146645

Molecular simulations of electrolyte structure and dynamics in lithium-sulfur battery solvents

NASA Astrophysics Data System (ADS)

Park, Chanbum; Kanduč, Matej; Chudoba, Richard; Ronneburg, Arne; Risse, Sebastian; Ballauff, Matthias; Dzubiella, Joachim

2018-01-01

The performance of modern lithium-sulfur (Li/S) battery systems critically depends on the electrolyte and solvent compositions. For fundamental molecular insights and rational guidance of experimental developments, efficient and sufficiently accurate molecular simulations are thus in urgent need. Here, we construct a molecular dynamics (MD) computer simulation model of representative state-of-the art electrolyte-solvent systems for Li/S batteries constituted by lithium-bis(trifluoromethane)sulfonimide (LiTFSI) and LiNO3 electrolytes in mixtures of the organic solvents 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL). We benchmark and verify our simulations by comparing structural and dynamic features with various available experimental reference systems and demonstrate their applicability for a wide range of electrolyte-solvent compositions. For the state-of-the-art battery solvent, we finally calculate and discuss the detailed composition of the first lithium solvation shell, the temperature dependence of lithium diffusion, as well as the electrolyte conductivities and lithium transference numbers. Our model will serve as a basis for efficient future predictions of electrolyte structure and transport in complex electrode confinements for the optimization of modern Li/S batteries (and related devices).

Ionic Liquid Catalyzed Electrolyte for Electrochemical Polyaniline Supercapacitors

NASA Astrophysics Data System (ADS)

Inamdar, A. I.; Im, Hyunsik; Jung, Woong; Kim, Hyungsang; Kim, Byungchul; Yu, Kook-Hyun; Kim, Jin-Sang; Hwang, Sung-Min

2013-05-01

The effect of different wt.% of ionic liquid "1,6-bis (trimethylammonium-1-yl) hexane tetrafluoroborate" in 0.5 M LiClO4+PC electrolyte on the supercapacitor properties of polyaniline (PANI) thin film are investigated. The PANI film is synthesized using electropolymerization of aniline in the presence of sulfuric acid. The electrochemical properties of the PANI thin film are studied by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) measurements. The optimum amount of the ionic liquid is found to be 2 wt.% which provides better ionic conductivity of the electrolyte. The highest specific capacitance of 259 F/g is obtained using the 2 wt.% electrolyte. This capacitance remains at up to 208 F/g (80% capacity retention) after 1000 charge-discharge cycles at a current density of 0.5 mA/g. The PANI film in the 2 wt.% ionic liquid catalyzed 0.5 M LiClO4+PC electrolyte shows small electrochemical resistance, better rate performance and higher cyclability. The increased ionic conductivity of the 2 wt.% ionic liquid catalyzed electrolyte causes a reduction in resistance at the electrode/electrolyte interface, which can be useful in electrochemically-preferred power devices for better applicability.

Lithium-ion battery electrolyte emissions analyzed by coupled thermogravimetric/Fourier-transform infrared spectroscopy

NASA Astrophysics Data System (ADS)

Bertilsson, Simon; Larsson, Fredrik; Furlani, Maurizio; Albinsson, Ingvar; Mellander, Bengt-Erik

2017-10-01

In the last few years the use of Li-ion batteries has increased rapidly, powering small as well as large applications, from electronic devices to power storage facilities. The Li-ion battery has, however, several safety issues regarding occasional overheating and subsequent thermal runaway. During such episodes, gas emissions from the electrolyte are of special concern because of their toxicity, flammability and the risk for gas explosion. In this work, the emissions from heated typical electrolyte components as well as from commonly used electrolytes are characterized using FT-IR spectroscopy and FT-IR coupled with thermogravimetric (TG) analysis, when heating up to 650 °C. The study includes the solvents EC, PC, DEC, DMC and EA in various single, binary and ternary mixtures with and without the LiPF6 salt, a commercially available electrolyte, (LP71), containing EC, DEC, DMC and LiPF6 as well as extracted electrolyte from a commercial 6.8 Ah Li-ion cell. Upon thermal heating, emissions of organic compounds and of the toxic decomposition products hydrogen fluoride (HF) and phosphoryl fluoride (POF3) were detected. The electrolyte and its components have also been extensively analyzed by means of infrared spectroscopy for identification purposes.

Recent Advances in Fast Ion Conducting Materials and Devices - Proceedings of the 2nd Asian Conference on Solid State Ionics

NASA Astrophysics Data System (ADS)

Chowdari, B. V. R.; Liu, Qingguo; Chen, Liquan

The Table of Contents for the book is as follows: * Preface * Invited Papers * Recent Trends in Solid State Ionics * Theoretical Aspects of Fast Ion Conduction in Solids * Chemical Bonding and Intercalation Processes in Framework Structures * Extra-Large Near-Electrode Regions and Diffusion Length on the Solid Electrolyte-Electrode Interface as Studied by Photo-EMF Method * Frequency Response of Glasses * XPS Studies on Ion Conducting Glasses * Characterization of New Ambient Temperature Lithium Polymer-Electrolyte * Recent Development of Polymer Electrolytes: Solid State Voltammetry in Polymer Electrolytes * Secondary Solid State Batteries: From Material Properties to Commercial Development * Silver Vanadium Oxide Bronze and its Applications for Electrochemical Devices * Study on β''-Alumina Solid Electrolyte and β Battery in SIC * Materials for Solid Oxide Fuel Cells * Processing for Super Superionic Ceramics * Hydrogen Production Using Oxide Ionic or Protonic Conductor * Ionically Conductive Sulfide-Based Lithium Glasses * Relation of Conductivity to Structure and Structural Relaxation in Ion-Conducting Glasses * The Mechanism of Ionic Conductivity in Glass * The Role of Synthesis and Structure in Solid State Ionics - Electrodes to Superconductors * Electrochromism in Spin-Coated Thin Films from Peroxo-Poly tungstate Solutions * Electrochemical Studies on High Tc Superconductors * Multivalence Fast Ionic Conductors - Montmorillonites * Contributed Papers * Volt-Ampere Characteristics and Interface Charge Transport in Solid Electrolytes * Internal Friction of Silver Chalcogenides * Thermal Expansion of Ionic and Superionic Solids * Improvement of PEO-LiCF3SO3 Complex Electrolytes Using Additives * Ionic Conductivity of Modified Poly (Methoxy Polyethylene Glycol Methacrylate) s-Lithium Salt Complexes * Solid Polymer Electrolytes of Crosslinked Polyethylene Glycol and Lithium Salts * Single Ionic Conductors Prepared by in Situ Polymerization of Methacrylic Acid Alkali Metal Salts in Polyethylene Oxide * Redox Behavior of Alkyl Viologens in Ion Conductive Polymer Solid * Ionic Conductivity of Interpenetrating Polymer Networks Containing LiClO4 * Electrochemical Behaviors of Porphyrins Incorporated into Solid Polymer Electrolytes * Lithium Ion Conducting Polymer Electrolytes * Electrochemical Synthesis of Polyaniline Thin Film * Electrochemical Aspect of Polyaniline Electrode in Aqueous Electrolyte * Mixed Cation Effect in Epoxy Resin - PEO-IPN Containing Perchlorate Salts * Conductivity, Raman and IR Studies on the Doped PEO-PPG Polymer Blends * Proton Conducting Polymeric Electrolytes from Poly (Ethyleneoxide) System * Surface Structure of Polymer Solid Ionic Conductors Based on Segmented Polyether Polyurethaneureas * Study on Addition Products of LiI and Diethylene Glycol etc. * Solid State Rechargeable Battery Using Paper Form Copper Ion Conductive Solid Electrolyte * Characterization of Electrode/Electrolyte Interfaces in Battery Li/PVAC-Li-Mont./Li1+xV3O8 by AC Impedance Method * Investigation on Reversibility of Vanadium Oxide Cathode Materials in Solid-State Battery * Preparation and Characterization of Silver Boromolybdate Solid State Batteries * The Electric Properties of the Trinary Cathode Material and its Application in Magnisium Solid State Cell * Electrical Properties and Phase Relation of Na2Mo0.1S0.9O4 Doped with Rare Earth Sulfate * New Electrochemical Probe for Rapid Determination of Silicon Concentration in Hot Metals * A New Theoretical EMF Expression for SOx(x = 2, 3) Sensors Based on Na2SO4 Solid Electrolyte * Evaluation of the Electrochemical SOx(x = 2, 3) Sensor with a Tubular Nasicon Electrolyte * The Response Time of a Modified Oxygen Sensor Using Zirconia Electrolyte * Preparation, Characteristics and Sintering Behavior of MgO-PSZ Powder * Reaction between La0.9MnO3 and Yttria Doped Zirconia * Development of the Extended-Life Oxygen Sensor of Caβ''-Al2O3 * Caβ''-Al2O3 Ultra-Low Oxygen Sensor * Measurement of Sulfur Concentration with Zirconia-Based Electrolyte Cell in Molten Iron * Influence of SO2 on the Conductivity of Calcia Stabilized Zirconia * Reactions between YSZ and La1-xCaxMnO3 as a Cathode for SOFC * Preparation and Electrical Properties of Lithium β''-Alumina * Influence of Lithia Content on Properties of β''-Alumina Ceramics * Electrical Conductivity of Solid Solutions of Na2SO4 with Na2SeO4 * Effect of Antagonist XO42- = MoO42- and WO42- Ion Substitution on the Electrical Conductivity of Li2SO4 : Li2CO3 Eutectic System * Study on the Electrical Properties and Structure of Multicrystal Materials Li5+xGe1-xCrxV3O12 * Preliminary Study on Synthesis of Silver Zirconium Silicophosphates by Sol - Gel Process * Sodium Ion Conduction in Iron(III) Exchanged Y Zeolite * Electrical Properties of V5O9+x (x = 0, 1) and CuxV5O9.1 * Electrical Properties of the Tetragonal ZrO2 Stabilized with CeO2, CeO2 + Gd2O3 * Study of Preparation and Ionic Conduction of Doped Barium Cerate Perovskite * Preparing Fine Alumina Powder by Homogeneous Precipitation Method for Fabricating β''-Al2O3 * Amorphous Lithium Ion Conductors in Li2S-SiS2-LiBO2 System * Mixed Alkali Effect of Glass Super Ionic Conductors * Electrical Property and Phase Separation, Crystallization Behavior of A Cu+-Conducting Glass * Investigation of Phase Separation and Crystallization for 0.4CuI-0.3 Cu2O-0.3P2O5 Glass by SEM and XRD * Study on the Lithium Solid Electrolytes of Li3N-LiX(X = F, Cl, Br, I)-B2O3 Ternary Systems * Synthesis and Characterization of the Li2O : P2O5 : WO3 Glasses * The Electrochromic Properties of Electrodeposited Ni-O Films in Nonaqueous Electrolytes * All Solid-State WO3-MnO2 Based Electrochromic Window * Electrochromism in Nickel Oxide Films * E S R of X-Irradiated Melt Quenched Li2SO4 * Mixed-Alkali Effect in the Li2O-Na2O-TeO2 Glass System * Electrical and Thermal Studies on Silver Tellurite Glasses * Late Entries (Invited Papers) * Proton Conducting Polymers * Light Scattering Studies on Superionic Conductor YSZ * Development of Thin Film Surface Modified Solid State Electrochemical Gas Sensors * Author Index * List of Participants

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.

The Evolution of High Temperature Gas Sensors.

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

Garzon, F. H.; Brosha, E. L.; Mukundan, R.

2001-01-01

Gas sensor technology based on high temperature solid electrolytes is maturing rapidly. Recent advances in metal oxide catalysis and thin film materials science has enabled the design of new electrochemical sensors. We have demonstrated prototype amperometric oxygen sensors, nernstian potentiometric oxygen sensors that operate in high sulfur environments, and hydrocarbon and carbon monoxide sensing mixed potentials sensors. Many of these devices exhibit part per million sensitivities, response times on the order of seconds and excellent long-term stability.

Hybrid MnO2/carbon nanotube-VN/carbon nanotube supercapacitors

NASA Astrophysics Data System (ADS)

Su, Y.; Zhitomirsky, I.

2014-12-01

Composite materials, containing fibrous VN nanoparticles and multiwalled carbon nanotubes (MWCNT) are prepared by a chemical method for application in electrochemical supercapacitors. We demonstrate for the first time that VN-MWCNT electrodes exhibit good capacitive behavior in 0.5 M Na2SO4 electrolyte in a negative voltage window of 0.9 V. Quartz crystal microbalance studies provide an insight into the mechanism of charge storage. Composite VN-MWCNT materials show significant improvement in capacitance, compared to individual VN and MWCNT materials. Testing results indicate that VN-MWCNT electrodes exhibit high specific capacitance at high mass loadings in the range of 10-30 mg cm-2, good capacitance retention at scan rates in the range of 2-200 mV s-1 and good cycling stability. The highest specific capacitance of 160 F g-1 is achieved at a scan rate of 2 mV s-1. The new findings open a new and promising strategy in the fabrication of hybrid devices based on VN. The proof-of-principle is demonstrated by the fabrication of hybrid supercapacitor devices based on VN-MWCNT negative electrodes and MnO2 -MWCNT positive electrodes with voltage window of 1.8 V in aqueous 0.5 M Na2SO4 electrolyte. The hybrid VN-MWCNT/MnO2-MWCNT supercapacitor cells show promising capacitive and power-energy characteristics.

High-energy green supercapacitor driven by ionic liquid electrolytes as an ultra-high stable next-generation energy storage device

NASA Astrophysics Data System (ADS)

Thangavel, Ranjith; Kannan, Aravindaraj G.; Ponraj, Rubha; Thangavel, Vigneysh; Kim, Dong-Won; Lee, Yun-Sung

2018-04-01

Development of supercapacitors with high energy density and long cycle life using sustainable materials for next-generation applications is of paramount importance. The ongoing challenge is to elevate the energy density of supercapacitors on par with batteries, while upholding the power and cyclability. In addition, attaining such superior performance with green and sustainable bio-mass derived compounds is very crucial to address the rising environmental concerns. Herein, we demonstrate the use of watermelon rind, a bio-waste from watermelons, towards high energy, and ultra-stable high temperature green supercapacitors with a high-voltage ionic liquid electrolyte. Supercapacitors assembled with ultra-high surface area, hierarchically porous carbon exhibits a remarkable performance both at room temperature and at high temperature (60 °C) with maximum energy densities of ∼174 Wh kg-1 (25 °C), and 177 Wh kg-1 (60 °C) - based on active mass of both electrodes. Furthermore, an ultra-high specific power of ∼20 kW kg-1 along with an ultra-stable cycling performance with 90% retention over 150,000 cycles has been achieved even at 60 °C, outperforming supercapacitors assembled with other carbon based materials. These results demonstrate the potential to develop high-performing, green energy storage devices using eco-friendly materials for next generation electric vehicles and other advanced energy storage systems.

NASA Tech Briefs, October 2011

NASA Technical Reports Server (NTRS)

2011-01-01

Topics covered include: Laser Truss Sensor for Segmented Telescope Phasing; Qualifications of Bonding Process of Temperature Sensors to Deep-Space Missions; Optical Sensors for Monitoring Gamma and Neutron Radiation; Compliant Tactile Sensors; Cytometer on a Chip; Measuring Input Thresholds on an Existing Board; Scanning and Defocusing Properties of Microstrip Reflectarray Antennas; Cable Tester Box; Programmable Oscillator; Fault-Tolerant, Radiation-Hard DSP; Sub-Shot Noise Power Source for Microelectronics; Asynchronous Message Service Reference Implementation; Zero-Copy Objects System; Delay and Disruption Tolerant Networking MACHETE Model; Contact Graph Routing; Parallel Eclipse Project Checkout; Technique for Configuring an Actively Cooled Thermal Shield in a Flight System; Use of Additives to Improve Performance of Methyl Butyrate-Based Lithium-Ion Electrolytes; Li-Ion Cells Employing Electrolytes with Methyl Propionate and Ethyl Butyrate Co-Solvents; Improved Devices for Collecting Sweat for Chemical Analysis; Tissue Photolithography; Method for Impeding Degradation of Porous Silicon Structures; External Cooling Coupled to Reduced Extremity Pressure Device; A Zero-Gravity Cup for Drinking Beverages in Microgravity; Co-Flow Hollow Cathode Technology; Programmable Aperture with MEMS Microshutter Arrays; Polished Panel Optical Receiver for Simultaneous RF/Optical Telemetry with Large DSN Antennas; Adaptive System Modeling for Spacecraft Simulation; Lidar-Based Navigation Algorithm for Safe Lunar Landing; Tracking Object Existence From an Autonomous Patrol Vehicle; Rad-Hard, Miniaturized, Scalable, High-Voltage Switching Module for Power Applications; and Architecture for a 1-GHz Digital RADAR.

Engineering three-dimensional hybrid supercapacitors and microsupercapacitors for high-performance integrated energy storage

PubMed Central

El-Kady, Maher F.; Ihns, Melanie; Li, Mengping; Hwang, Jee Youn; Mousavi, Mir F.; Chaney, Lindsay; Lech, Andrew T.; Kaner, Richard B.

2015-01-01

Supercapacitors now play an important role in the progress of hybrid and electric vehicles, consumer electronics, and military and space applications. There is a growing demand in developing hybrid supercapacitor systems to overcome the energy density limitations of the current generation of carbon-based supercapacitors. Here, we demonstrate 3D high-performance hybrid supercapacitors and microsupercapacitors based on graphene and MnO2 by rationally designing the electrode microstructure and combining active materials with electrolytes that operate at high voltages. This results in hybrid electrodes with ultrahigh volumetric capacitance of over 1,100 F/cm3. This corresponds to a specific capacitance of the constituent MnO2 of 1,145 F/g, which is close to the theoretical value of 1,380 F/g. The energy density of the full device varies between 22 and 42 Wh/l depending on the device configuration, which is superior to those of commercially available double-layer supercapacitors, pseudocapacitors, lithium-ion capacitors, and hybrid supercapacitors tested under the same conditions and is comparable to that of lead acid batteries. These hybrid supercapacitors use aqueous electrolytes and are assembled in air without the need for expensive “dry rooms” required for building today’s supercapacitors. Furthermore, we demonstrate a simple technique for the fabrication of supercapacitor arrays for high-voltage applications. These arrays can be integrated with solar cells for efficient energy harvesting and storage systems. PMID:25831542

Engineering three-dimensional hybrid supercapacitors and microsupercapacitors for high-performance integrated energy storage.

PubMed

El-Kady, Maher F; Ihns, Melanie; Li, Mengping; Hwang, Jee Youn; Mousavi, Mir F; Chaney, Lindsay; Lech, Andrew T; Kaner, Richard B

2015-04-07

Supercapacitors now play an important role in the progress of hybrid and electric vehicles, consumer electronics, and military and space applications. There is a growing demand in developing hybrid supercapacitor systems to overcome the energy density limitations of the current generation of carbon-based supercapacitors. Here, we demonstrate 3D high-performance hybrid supercapacitors and microsupercapacitors based on graphene and MnO2 by rationally designing the electrode microstructure and combining active materials with electrolytes that operate at high voltages. This results in hybrid electrodes with ultrahigh volumetric capacitance of over 1,100 F/cm(3). This corresponds to a specific capacitance of the constituent MnO2 of 1,145 F/g, which is close to the theoretical value of 1,380 F/g. The energy density of the full device varies between 22 and 42 Wh/l depending on the device configuration, which is superior to those of commercially available double-layer supercapacitors, pseudocapacitors, lithium-ion capacitors, and hybrid supercapacitors tested under the same conditions and is comparable to that of lead acid batteries. These hybrid supercapacitors use aqueous electrolytes and are assembled in air without the need for expensive "dry rooms" required for building today's supercapacitors. Furthermore, we demonstrate a simple technique for the fabrication of supercapacitor arrays for high-voltage applications. These arrays can be integrated with solar cells for efficient energy harvesting and storage systems.

Facile synthesis of Zn1-xCoxO/ZnO core/shell nanostructures and their application to dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Manthina, Venkata; Agrios, Alexander G.

2017-04-01

Heterostructures consisting of Co-doped ZnO nanorod cores encased in an undoped ZnO shell were successfully synthesized to serve as photoanodes for dye-sensitized solar cells (DSSCs) by a two-step chemical bath deposition (CBD) technique. This yields a highly favorable structure in which electrons injected from the dye into the ZnO then step down in energy into the Co-doped core, where the electron is transported to the collector while the ZnO shell acts as a barrier to recombination with the electrolyte. Incorporation of the core/shell structures into DSSCs resulted in large improvements in photocurrent and photovoltage in comparison to pure ZnO nanorod-based DSSCs. SEM and XRD characterization indicate incorporation of the Co2+ into the ZnO matrix, without separation of the Co into other phases, providing no energy barriers. In addition, the ability of these heterostructures to reduce recombination rates in redox couples with fast recombination rates was probed by comparing DSSC device performance in both iodide/triiodide-based and ferrocene/ferrocenium-based electrolytes.

Electronic Health Management

NASA Technical Reports Server (NTRS)

Celaya, Jose R.; Saha, Sankalita; Goebel, Kai

2011-01-01

Accelerated aging methodologies for electrolytic components have been designed and accelerated aging experiments have been carried out. The methodology is based on imposing electrical and/or thermal overstresses via electrical power cycling in order to mimic the real world operation behavior. Data are collected in-situ and offline in order to periodically characterize the devices' electrical performance as it ages. The data generated through these experiments are meant to provide capability for the validation of prognostic algorithms (both model-based and data-driven). Furthermore, the data allow validation of physics-based and empirical based degradation models for this type of capacitor. A first set of models and algorithms has been designed and tested on the data.

Preliminary Evaluations of Polymer-based Lithium Battery Electrolytes Under Development for the Polymer Electrolyte Rechargeable Systems Program

NASA Technical Reports Server (NTRS)

Manzo, Michelle A.; Bennett, William R.

2003-01-01

A component screening facility has been established at The NASA Glenn Research Center (GRC) to evaluate candidate materials for next generation, lithium-based, polymer electrolyte batteries for aerospace applications. Procedures have been implemented to provide standardized measurements of critical electrolyte properties. These include ionic conductivity, electronic resistivity, electrochemical stability window, cation transference number, salt diffusion coefficient and lithium plating efficiency. Preliminary results for poly(ethy1ene oxide)-based polymer electrolyte and commercial liquid electrolyte are presented.

21 CFR 862.1600 - Potassium test system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Potassium test system. 862.1600 Section 862.1600....1600 Potassium test system. (a) Identification. A potassium test system is a device intended to measure potassium in serum, plasma, and urine. Measurements obtained by this device are used to monitor electrolyte...

21 CFR 862.1600 - Potassium test system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Potassium test system. 862.1600 Section 862.1600....1600 Potassium test system. (a) Identification. A potassium test system is a device intended to measure potassium in serum, plasma, and urine. Measurements obtained by this device are used to monitor electrolyte...

21 CFR 862.1600 - Potassium test system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Potassium test system. 862.1600 Section 862.1600....1600 Potassium test system. (a) Identification. A potassium test system is a device intended to measure potassium in serum, plasma, and urine. Measurements obtained by this device are used to monitor electrolyte...

21 CFR 862.1600 - Potassium test system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Potassium test system. 862.1600 Section 862.1600....1600 Potassium test system. (a) Identification. A potassium test system is a device intended to measure potassium in serum, plasma, and urine. Measurements obtained by this device are used to monitor electrolyte...

21 CFR 862.1600 - Potassium test system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Potassium test system. 862.1600 Section 862.1600....1600 Potassium test system. (a) Identification. A potassium test system is a device intended to measure potassium in serum, plasma, and urine. Measurements obtained by this device are used to monitor electrolyte...

Facilitated ion transport in all-solid-state flexible supercapacitors.

PubMed

Choi, Bong Gill; Hong, Jinkee; Hong, Won Hi; Hammond, Paula T; Park, HoSeok

2011-09-27

The realization of highly flexible and all-solid-state energy-storage devices strongly depends on both the electrical properties and mechanical integrity of the constitutive materials and the controlled assembly of electrode and solid electrolyte. Herein we report the preparation of all-solid-state flexible supercapacitors (SCs) through the easy assembly of functionalized reduced graphene oxide (f-RGO) thin films (as electrode) and solvent-cast Nafion electrolyte membranes (as electrolyte and separator). In particular, the f-RGO-based SCs (f-RGO-SCs) showed a 2-fold higher specific capacitance (118.5 F/g at 1 A/g) and rate capability (90% retention at 30 A/g) compared to those of all-solid-state graphene SCs (62.3 F/g at 1A/g and 48% retention at 30 A/g). As proven by the 4-fold faster relaxation of the f-RGO-SCs than that of the RGO-SCs and more capacitive behavior of the former at the low-frequency region, these results were attributed to the facilitated ionic transport at the electrical double layer by means of the interfacial engineering of RGO by Nafion. Moreover, the superiority of all-solid-state flexible f-RGO-SCs was demonstrated by the good performance durability under the 1000 cycles of charging and discharging due to the mechanical integrity as a consequence of the interconnected networking structures. Therefore, this research provides new insight into the rational design and fabrication of all-solid-state flexible energy-storage devices as well as the fundamental understanding of ion and charge transport at the interface. © 2011 American Chemical Society

Materials Compositions for Lithium Ion Batteries with Extended Thermal Stability

NASA Astrophysics Data System (ADS)

Kalaga, Kaushik

Advancements in portable electronics have generated a pronounced demand for rechargeable energy storage devices with superior capacity and reliability. Lithium ion batteries (LIBs) have evolved as the primary choice of portable power for several such applications. While multiple variations have been developed, safety concerns of commercial technologies limit them to atmospheric temperature operability. With several niche markets such as aerospace, defense and oil & gas demanding energy storage at elevated temperatures, there is a renewed interest in developing rechargeable batteries that could survive temperatures beyond 100°C. Instability of critical battery components towards extreme thermal and electrochemical conditions limit their usability at high temperatures. This study deals with developing material configurations for LIB components to stabilize them at such temperatures. Flammable organic solvent based electrolytes and low melting polymer based separators have been identified as the primary bottleneck for LIBs to survive increasing temperature. Furthermore, thermally activated degradation processes in oxide based electrodes have been identified as the reason for their limited lifetime. A quasi-solid composite comprising of room temperature ionic liquids (RTILs) and Clay was developed as an electrolyte/separator hybrid and tested to be stable up to 120°C. These composites facilitate complete reversible Li intercalation in lithium titanate (LTO) with a stable capacity of 120 mAh g-1 for several cycles of charge and discharge while simultaneously resisting severe thermal conditions. Modified phosphate based electrodes were introduced as a reliable alternative for operability at high temperatures in this study. These systems were shown to deliver stable reversible capacity for numerous charge/discharge cycles at elevated temperatures. Higher lithium intercalation potential of the developed cathode materials makes them interesting candidates for high voltage lithium batteries, which may be dubbed as the next generation devices. Architectural engineering of battery components to amplify the device performance is also discussed. 3D electrode structures developed using CVD and electrodeposition techniques demonstrated significant enhancement in performance when compared to their 2D analogues. The study has established the prospects of LIBs at high temperatures through material tuning and engineering approaches and envisage a scope for viable devices.

Performance of Multi Walled Carbon Nanotubes Grown on Conductive Substrates as Supercapacitors Electrodes using Organic and Ionic liquid electrolytes

NASA Astrophysics Data System (ADS)

Winchester, Andrew; Ghosh, Sujoy; Turner, Ben; Zhang, X. F.; Talapatra, Saikat

2012-02-01

In this work we will present the use of Multi Walled Carbon Nanotubes (MWNT) directly grown on inconel substrates via chemical vapor deposition, as electrode materials for electrochemical double layer capacitors (EDLC). The performance of the MWNT EDLC electrodes were investigated using two electrolytes, an organic electrolyte, tetraethylammonium tetrafluoroborate in propylene carbonate (Et4NBF4 in PC), and a room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6). Cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy measurements to obtain values for the capacitance and internal resistance of these devices will be presented and compared.

Al2O3 Disk Supported Si3N4 Hydrogen Purification Membrane for Low Temperature Polymer Electrolyte Membrane Fuel Cells

PubMed Central

Liu, Xiaoteng; Christensen, Paul A.; Kelly, Stephen M.; Rocher, Vincent; Scott, Keith

2013-01-01

Reformate gas, a commonly employed fuel for polymer electrolyte membrane fuel cells (PEMFCs), contains carbon monoxide, which poisons Pt-containing anodes in such devices. A novel, low-cost mesoporous Si3N4 selective gas separation material was tested as a hydrogen clean-up membrane to remove CO from simulated feed gas to single-cell PEMFC, employing Nafion as the polymer electrolyte membrane. Polarization and power density measurements and gas chromatography showed a clear effect of separating the CO from the gas mixture; the performance and durability of the fuel cell was thereby significantly improved. PMID:24957065

Al2O3 Disk Supported Si3N4 Hydrogen Purification Membrane for Low Temperature Polymer Electrolyte Membrane Fuel Cells.

PubMed

Liu, Xiaoteng; Christensen, Paul A; Kelly, Stephen M; Rocher, Vincent; Scott, Keith

2013-12-05

Reformate gas, a commonly employed fuel for polymer electrolyte membrane fuel cells (PEMFCs), contains carbon monoxide, which poisons Pt-containing anodes in such devices. A novel, low-cost mesoporous Si3N4 selective gas separation material was tested as a hydrogen clean-up membrane to remove CO from simulated feed gas to single-cell PEMFC, employing Nafion as the polymer electrolyte membrane. Polarization and power density measurements and gas chromatography showed a clear effect of separating the CO from the gas mixture; the performance and durability of the fuel cell was thereby significantly improved.

PC based electrolytes with LiDFOB as an alternative salt for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Knight, Brandon M.

Lithium-ion batteries (LIBs) have been greatly sought after as a source of renewable energy storage. LIBs have a wide range of applications including but not limited portable electronic devices, electric vehicles, and power tools. As a direct result of their commercial viability an insatiable hunger for knowledge, advancement within the field of LIBs has been omnipresent for the last two decades. However, there are set backs evident within the LIB field; most notably the limitations of standard electrolyte formulations and LiPF6 lithium salt. The standard primary carbonate of ethylene carbonate (EC) has a very limited operating range due to its innate physical properties, and the LiPF6 salt is known to readily decompose to form HF which can further degrade LIB longevity. The goal of our research is to explore the use of a new primary salt LiDFOB in conjunction with a propylene carbonate based electrolyte to establish a more flexible electrolyte formulation by constructing coin cells and cycling them under various conditions to give a clear understanding of each formulation inherent performance capabilities. Our studies show that 1.2M LiDFOB in 3:7 PC/EMC + 1.5% VC is capable of performing comparably to the standard 1.2M LiPF6 in 3:7 EC/EMC at 25°C and the PC electrolyte also illustrates performance superior to the standard at 55°C. The degradation of lithium manganese spinel electrodes, including LiNi 0.5Mn1.5O4, is an area of great concern within the field of lithium ion batteries (LIBs). Manganese containing cathode materials frequently have problems associated with Mn dissolution which significantly reduces the cycle life of LIB. Thus the stability of the cathode material is paramount to the performance of Mn spinel cathode materials in LIBs. In an effort to gain a better understanding of the stability of LiNi0.5 Mn1.5O4 in common LiPF6/carbonate electrolytes, samples were stored at elevated temperature in the presence of electrolyte. Then after storage both the electrolyte solution and uncharged cathode particles were analyzed. The solid cathode particles were analyzed via scanning electron microscopy (SEM) whereas the electrolyte solution was analyzed using inductively coupled plasma mass spectroscopy (ICP-MS). The SEM analysis assists with elucidation of changes to the surfaces of the cathode particles. The ICP-MS of the electrolyte allows the determination of the extent of Mn and Ni dissolution. Samples of LiNi0.5Mn1.5O4 with different crystal surface facets were prepared to investigate the role of particle morphology in Mn and Ni dissolution. The factors affecting Mn and Ni dissolution and methods to inhibit dissolution will be discussed.

Dye-sensitized solar cells employing a SnO2-TiO2 core-shell structure made by atomic layer deposition.

PubMed

Karlsson, Martin; Jõgi, Indrek; Eriksson, Susanna K; Rensmo, Håkan; Boman, Mats; Boschloo, Gerrit; Hagfeldt, Anders

2013-01-01

This paper describes the synthesis and characterization of core-shell structures, based on SnO2 and TiO2, for use in dye-sensitized solar cells (DSC). Atomic layer deposition is employed to control and vary the thickness of the TiO2 shell. Increasing the TiO2 shell thickness to 2 nm improved the device performance of liquid electrolyte-based DSC from 0.7% to 3.5%. The increase in efficiency originates from a higher open-circuit potential and a higher short-circuit current, as well as from an improvement in the electron lifetime. SnO2-TiO2 core-shell DSC devices retain their photovoltage in darkness for longer than 500 seconds, demonstrating that the electrons are contained in the core material. Finally core-shell structures were used for solid-state DSC applications using the hole transporting material 2,2',7,7',-tetrakis(N, N-di-p-methoxyphenyl-amine)-9,9',-spirofluorene. Similar improvements in device performance were obtained for solid-state DSC devices.

New Approach for High-Voltage Electrical Double-Layer Capacitors Using Vertical Graphene Nanowalls with and without Nitrogen Doping.

PubMed

Chi, Yu-Wen; Hu, Chi-Chang; Shen, Hsiao-Hsuan; Huang, Kun-Ping

2016-09-14

Integrating various devices to achieve high-performance energy storage systems to satisfy various demands in modern societies become more and more important. Electrical double-layer capacitors (EDLCs), one kind of the electrochemical capacitors, generally provide the merits of high charge-discharge rates, extremely long cycle life, and high efficiency in electricity capture/storage, leading to a desirable device of electricity management from portable electronics to hybrid vehicles or even smart grid application. However, the low cell voltage (2.5-2.7 V in organic liquid electrolytes) of EDLCs lacks the direct combination of Li-ion batteries (LIBs) and EDLCs for creating new functions in future applications without considering the issue of a relatively low energy density. Here we propose a guideline, "choosing a matching pair of electrode materials and electrolytes", to effectively extend the cell voltage of EDLCs according to three general strategies. Based on the new strategy proposed in this work, materials with an inert surface enable to tolerate a wider potential window in commercially available organic electrolytes in comparison with activated carbons (ACs). The binder-free, vertically grown graphene nanowalls (GNW) and nitrogen-doped GNW (NGNW) electrodes respectively provide good examples for extending the upper potential limit of a positive electrode of EDLCs from 0.1 to 1.5 V (vs Ag/AgNO3) as well as the lower potential limit of a negative electrode of EDLCs from -2.0 V to ca. -2.5 V in 1 M TEABF4/PC (propylene carbonate) compared to ACs. This newly designed asymmetric EDLC exhibits a cell voltage of 4 V, specific energy of 52 Wh kg(-1) (ca. a device energy density of 13 Wh kg(-1)), and specific power of 8 kW kg(-1) and ca. 100% retention after 10,000 cycles charge-discharge, reducing the series number of EDLCs to enlarge the module voltage and opening the possibility for directly combining EDLCs and LIBs in advanced applications.

Strong, Tough Glass Composites Developed for Solid Oxide Fuel Cell Seals

NASA Technical Reports Server (NTRS)

Bansal, Narottam P.; Choi, Sung R.

2005-01-01

A fuel cell is an electrochemical device that continuously converts the chemical energy of a fuel directly into electrical energy. It consists of an electrolyte, an anode, and a cathode. Various types of fuel cells are available, such as direct methanol fuel cells, alkaline fuel cells, proton-exchange-membrane fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, and solid oxide fuel cells (SOFCs). The salient features of an SOFC are all solid construction and high-temperature electrochemical-reaction-based operation, resulting in clean, efficient power generation from a variety of fuels. SOFCs are being developed for a broad range of applications, such as portable electronic devices, automobiles, power generation, and aeronautics.

Impact of isoelectric points of nanopowders in electrolytes on electrochemical characteristics of dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Mohanty, Shyama Prasad; Bhargava, Parag

2012-11-01

Nanoparticle loaded quasi solid electrolytes are important from the view point of developing electrolytes for dye sensitized solar cells (DSSCs) having long term stability. The present work shows the influence of isoelectric point of nanopowders in electrolyte on the photoelectrochemical characteristics of DSSCs. Electrolytes with nanopowders of silica, alumina and magnesia which have widely differing isoelectric points are used in the study. Adsorption of ions from the electrolyte on the nanopowder surface, characterized by zeta potential measurement, show that cations get adsorbed on silica, alumina surface while anions get adsorbed on magnesia surface. The electrochemical characteristics of nanoparticulate loaded electrolytes are examined through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). DSSCs fabricated using liquid, silica or alumina loaded electrolytes exhibit almost similar performance. But interestingly, the magnesia loaded electrolyte-based cell show lower short circuit current density (JSC) and much higher open circuit voltage (VOC), which is attributed to adsorption of anions. Such anionic adsorption prevents the dark reaction in magnesia loaded electrolyte-based cell and thus, enhances the VOC by almost 100 mV as compared to liquid electrolyte based cell. Also, higher electron life time at the titania/electrolyte interface is observed in magnesia loaded electrolyte-based cell as compared to others.

Thread-like supercapacitors based on one-step spun nanocomposite yarns.

PubMed

Meng, Qinghai; Wang, Kai; Guo, Wei; Fang, Jin; Wei, Zhixiang; She, Xilin

2014-08-13

Thread-like electronic devices have attracted great interest because of their potential applications in wearable electronics. To produce high-performance, thread-like supercapacitors, a mixture of stable dispersions of single-walled carbon nanotubes and conducting polyaniline nanowires are prepared. Then, the mixture is spun into flexible yarns with a polyvinyl alcohol outer sheath by a one-step spinning process. The composite yarns show excellent mechanical properties and high electrical conductivities after sufficient washing to remove surfactants. After applying a further coating layer of gel electrolyte, two flexible yarns are twisted together to form a thread-like supercapacitor. The supercapacitor based on these two yarns (SWCNTs and PAniNWs) possesses a much higher specific capacitance than that based only on pure SWCNTs yarns, making it an ideal energy-storage device for wearable electronics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid characterization of lithium ion battery electrolytes and thermal aging products by low-temperature plasma ambient ionization high-resolution mass spectrometry.

PubMed

Vortmann, Britta; Nowak, Sascha; Engelhard, Carsten

2013-03-19

Lithium ion batteries (LIBs) are key components for portable electronic devices that are used around the world. However, thermal decomposition products in the battery reduce its lifetime, and decomposition processes are still not understood. In this study, a rapid method for in situ analysis and reaction monitoring in LIB electrolytes is presented based on high-resolution mass spectrometry (HR-MS) with low-temperature plasma probe (LTP) ambient desorption/ionization for the first time. This proof-of-principle study demonstrates the capabilities of ambient mass spectrometry in battery research. LTP-HR-MS is ideally suited for qualitative analysis in the ambient environment because it allows direct sample analysis independent of the sample size, geometry, and structure. Further, it is environmental friendly because it eliminates the need of organic solvents that are typically used in separation techniques coupled to mass spectrometry. Accurate mass measurements were used to identify the time-/condition-dependent formation of electrolyte decomposition compounds. A LIB model electrolyte containing ethylene carbonate and dimethyl carbonate was analyzed before and after controlled thermal stress and over the course of several weeks. Major decomposition products identified include difluorophosphoric acid, monofluorophosphoric acid methyl ester, monofluorophosphoric acid dimethyl ester, and hexafluorophosphate. Solvents (i.e., dimethyl carbonate) were partly consumed via an esterification pathway. LTP-HR-MS is considered to be an attractive method for fundamental LIB studies.

Relationship between pore size and reversible and irreversible immobilization of ionic liquid electrolytes in porous carbon under applied electric potential

DOE PAGES

Mahurin, Shannon M.; Mamontov, Eugene; Thompson, Matthew W.; ...

2016-10-04

Transport of electrolytes in nanoporous carbon-based electrodes largely defines the function and performance of energy storage devices. Here, using molecular dynamics simulation and quasielastic neutron scattering, we investigate the microscopic dynamics of a prototypical ionic liquid electrolyte, [emim][Tf 2N], under applied electric potential in carbon materials with 6.7 nm and 1.5 nm pores. The simulations demonstrate the formation of dense layers of counter-ions near the charged surfaces, which is reversible when the polarity is reversed. In the experiment, the ions immobilized near the surface manifest themselves in the elastic scattering signal. The experimentally observed ion immobilization near the wall ismore » fully reversible as a function of the applied electric potential in the 6.7 nm, but not in the 1.5 nm nanopores. In the latter case, remarkably, the first application of the electric potential leads to apparently irreversible immobilization of cations or anions, depending on the polarity, near the carbon pore walls. This unexpectedly demonstrates that in carbon electrode materials with the small pores, which are optimal for energy storage applications, the polarity of the electrical potential applied for the first time after the introduction of an ionic liquid electrolyte may define the decoration of the small pore walls with ions for prolonged periods of time and possibly for the lifetime of the electrode.« less

Eyeglasses based wireless electrolyte and metabolite sensor platform.

PubMed

Sempionatto, Juliane R; Nakagawa, Tatsuo; Pavinatto, Adriana; Mensah, Samantha T; Imani, Somayeh; Mercier, Patrick; Wang, Joseph

2017-05-16

The demand for wearable sensors has grown rapidly in recent years, with increasing attention being given to epidermal chemical sensing. Here, we present the first example of a fully integrated eyeglasses wireless multiplexed chemical sensing platform capable of real-time monitoring of sweat electrolytes and metabolites. The new concept has been realized by integrating an amperometric lactate biosensor and a potentiometric potassium ion-selective electrode into the two nose-bridge pads of the glasses and interfacing them with a wireless electronic backbone placed on the glasses' arms. Simultaneous real-time monitoring of sweat lactate and potassium levels with no apparent cross-talk is demonstrated along with wireless signal transduction. The electrochemical sensors were screen-printed on polyethylene terephthalate (PET) stickers and placed on each side of the glasses' nose pads in order to monitor sweat metabolites and electrolytes. The electronic backbone on the arms of the glasses' frame offers control of the amperometric and potentiometric transducers and enables Bluetooth wireless data transmission to the host device. The new eyeglasses system offers an interchangeable-sensor feature in connection with a variety of different nose-bridge amperometric and potentiometric sensor stickers. For example, the lactate bridge-pad sensor was replaced with a glucose one to offer convenient monitoring of sweat glucose. Such a fully integrated wireless "Lab-on-a-Glass" multiplexed biosensor platform can be readily expanded for the simultaneous monitoring of additional sweat electrolytes and metabolites.

The Electrochemical Performance of Silicon Nanoparticles in Concentrated Electrolyte.

PubMed

Chang, Zeng-Hua; Wang, Jian-Tao; Wu, Zhao-Hui; Gao, Min; Wu, Shuai-Jin; Lu, Shi-Gang

2018-06-11

Silicon is a promising material for anodes in energy-storage devices. However, excessive growth of a solid-electrolyte interphase (SEI) caused by the severe volume change during the (de)lithiation processes leads to dramatic capacity fading. Here, we report a super-concentrated electrolyte composed of lithium bis(fluorosulfonyl)imide (LiFSI) and propylene carbonate (PC) with a molar ratio of 1:2 to improve the cycling performance of silicon nanoparticles (SiNPs). The SiNP electrode shows a remarkably improved cycling performance with an initial delithiation capacity of approximately 3000 mAh g -1 and a capacity of approximately 2000 mAh g -1 after 100 cycles, exhibiting about 6.8 times higher capacity than the cells with dilute electrolyte LiFSI-(PC) 8 . Raman spectra reveal that most of the PC solvent and FSI anions are complexed by Li + to form a specific solution structure like a fluid polymeric network. The reduction of FSI anions starts to play an important role owing to the increased concentration of contact ion pairs (CIPs) or aggregates (AGGs), which contribute to the formation of a more mechanically robust and chemically stable complex SEI layer. The complex SEI layer can effectively suppress the morphology evolution of silicon particles and self-limit the excessive growth, which mitigates the crack propagation of the silicon electrode and the deterioration of the kinetics. This study will provide a new direction for screening cycling-stable electrolytes for silicon-based electrodes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed

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

2015-06-23

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

Visualization of energy: light dose indicator based on electrochromic gyroid nano-materials

NASA Astrophysics Data System (ADS)

Wei, Di; Scherer, Maik R. J.; Astley, Michael; Steiner, Ullrich

2015-06-01

The typical applications of electrochromic devices do not make use of the charge-dependent, gradual optical response due to their slow voltage-sensitive coloration. However, in this paper we present a design for a reusable, self-powered light dose indicator consisting of a solar cell and a gyroid-structured nickel oxide (NiO) electrochromic display that measures the cumulative charge per se, making use of the efficient voltage-sensitive coloration of gyroid materials. To circumvent the stability issues associated with the standard aqueous electrolyte that is typically accompanied by water splitting and gas evolution, we investigate a novel nano-gyroid NiO electrochromic device based on organic solvents of 1,1,1,3,3,3-hexafluoropropan-2-ol, and room temperature ionic liquid (RTIL) triethylsulfonium bis(trifluoromethylsulfonyl) imide ([SET3][TFSI]) containing lithium bis(trifluoromethylsulfonyl) imide. We show that an effective light dose indicator can be enabled by nano-gyroid NiO with RTIL; this proves to be a reliable device since it does not involve solvent degradation or gas generation.

Self-Protection of Electrochemical Storage Devices via a Thermal Reversible Sol-Gel Transition.

PubMed

Yang, Hui; Liu, Zhiyuan; Chandran, Bevita K; Deng, Jiyang; Yu, Jiancan; Qi, Dianpeng; Li, Wenlong; Tang, Yuxin; Zhang, Chenguang; Chen, Xiaodong

2015-10-07

Thermal self-protected intelligent electrochemical storage devices are fabricated using a reversible sol-gel transition of the electrolyte, which can decrease the specific capacitance and increase and enable temperature-dependent charging and discharging rates in the device. This work represents proof of a simple and useful concept, which shows tremendous promise for the safe and controlled power delivery in electrochemical devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Excellent Resistive Switching Performance of Cu-Se-Based Atomic Switch Using Lanthanide Metal Nanolayer at the Cu-Se/Al2O3 Interface.

PubMed

Woo, Hyunsuk; Vishwanath, Sujaya Kumar; Jeon, Sanghun

2018-03-07

The next-generation electronic society is dependent on the performance of nonvolatile memory devices, which has been continuously improving. In the last few years, many memory devices have been introduced. However, atomic switches are considered to be a simple and reliable basis for next-generation nonvolatile devices. In general, atomic switch-based resistive switching is controlled by electrochemical metallization. However, excess ion injection from the entire area of the active electrode into the switching layer causes device nonuniformity and degradation of reliability. Here, we propose the fabrication of a high-performance atomic switch based on Cu x -Se 1- x by inserting lanthanide (Ln) metal buffer layers such as neodymium (Nd), samarium (Sm), dysprosium (Dy), or lutetium (Lu) between the active metal layer and the electrolyte. Current-atomic force microscopy results confirm that Cu ions penetrate through the Ln-buffer layer and form thin conductive filaments inside the switching layer. Compared with the Pt/Cu x -Se 1- x /Al 2 O 3 /Pt device, the optimized Pt/Cu x -Se 1- x /Ln/Al 2 O 3 /Pt devices show improvement in the on/off resistance ratio (10 2 -10 7 ), retention (10 years/85 °C), endurance (∼10 000 cycles), and uniform resistance state distribution.

In situ and nonvolatile photoluminescence tuning and nanodomain writing demonstrated by all-solid-state devices based on graphene oxide.

PubMed

Tsuchiya, Takashi; Tsuruoka, Tohru; Terabe, Kazuya; Aono, Masakazu

2015-02-24

In situ and nonvolatile tuning of photoluminescence (PL) has been achieved based on graphene oxide (GO), the PL of which is receiving much attention because of various potential applications of the oxide (e.g., display, lighting, and nano-biosensor). The technique is based on in situ and nonvolatile tuning of the sp(2) domain fraction to the sp(3) domain fraction (sp(2)/sp(3) fraction) in GO through an electrochemical redox reaction achieved by solid electrolyte thin films. The all-solid-state variable PL device was fabricated by GO and proton-conducting mesoporous SiO2 thin films, which showed an extremely low PL background. The device successfully tuned the PL peak wavelength in a very wide range from 393 to 712 nm, covering that for chemically tuned GO, by adjusting the applied DC voltage within several hundred seconds. We also demonstrate the sp(2)/sp(3) fraction tuning using a conductive atomic force microscope. The device achieved not only writing, but also erasing of the sp(2)/sp(3)-fraction-tuned nanodomain (both directions operation). The combination of these techniques is applicable to a wide range of nano-optoelectronic devices including nonvolatile PL memory devices and on-demand rewritable biosensors that can be integrated into nano- and microtips which are transparent, ultrathin, flexible, and inexpensive.

Unusual effect of the magnetic field component of the microwave radiation on aqueous electrolyte solutions.

PubMed

Horikoshi, Satoshi; Sumi, Takuya; Serpone, Nick

2012-01-01

The heating characteristics of aqueous electrolyte solutions (NaCl, KCl, CaCl2, NaBF4, and NaBr) of varying concentrations in ultrapure water by 2.45 GHz microwave radiation from a single-mode resonance microwave device and a semiconductor microwave generator were examined under conditions where the electric field (E-field) was dominant and where the magnetic field (H-field) dominated. Although magnetic field heating is not generally used in microwave chemistry, the electrolyte solutions were heated almost entirely by the microwaves' H-field. The heating rates under H-field irradiation at the higher concentrations of electrolytes (0.125 M to 0.50 M) exceeded the rates under E-field irradiation. This inversion phenomenon in heating is described in terms of the penetration depth of the microwaves. On the other hand, the action of the microwave radiation on ethylene glycol containing an electrolyte differed from that observed for water under E-field and H-field conditions.

Lithium-ion battery electrolyte mobility at nano-confined graphene interfaces

PubMed Central

Moeremans, Boaz; Cheng, Hsiu-Wei; Hu, Qingyun; Garces, Hector F.; Padture, Nitin P.; Renner, Frank Uwe; Valtiner, Markus

2016-01-01

Interfaces are essential in electrochemical processes, providing a critical nanoscopic design feature for composite electrodes used in Li-ion batteries. Understanding the structure, wetting and mobility at nano-confined interfaces is important for improving the efficiency and lifetime of electrochemical devices. Here we use a Surface Forces Apparatus to quantify the initial wetting of nanometre-confined graphene, gold and mica surfaces by Li-ion battery electrolytes. Our results indicate preferential wetting of confined graphene in comparison with gold or mica surfaces because of specific interactions of the electrolyte with the graphene surface. In addition, wetting of a confined pore proceeds via a profoundly different mechanism compared with wetting of a macroscopic surface. We further reveal the existence of molecularly layered structures of the confined electrolyte. Nanoscopic confinement of less than 4–5 nm and the presence of water decrease the mobility of the electrolyte. These results suggest a lower limit for the pore diameter in nanostructured electrodes. PMID:27562148

Pyrrole as a promising electrolyte additive to trap polysulfides for lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

Yang, Wu; Yang, Wang; Song, Ailing; Gao, Lijun; Sun, Gang; Shao, Guangjie

2017-04-01

Lithium-sulfur batteries are a promising energy storage devices beyond conventional lithium ion batteries. However, the "shuttle effect" of soluble polysulfides is a major barrier between electrodes, resulting in rapid capacity fading. To address above issue, pyrrole has been investigated as an electrolyte additive to trap polysulfides. When pyrrole is added into electrolyte, a surface protective layer of polypyrrole can be formed on the sulfur cathode, which not only acts as a conductive agent to provide an effective electron conduction path but also acts as an absorbing agent and barrier layer suppressing the diffusion of polysulfide intermediates. The results demonstrate that an appropriate amount of pyrrole added into the electrolyte leads to excellent cycling stability and rate capability. Apparently, pyrrole is an effective additive for the entrapment of polysulfides of lithium-sulfur batteries.

Toxicity of materials used in the manufacture of lithium batteries

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

Archuleta, M.M.

1994-05-01

The growing interest in battery systems has led to major advances in high-energy and/or high-power-density lithium batteries. Potential applications for lithium batteries include radio transceivers, portable electronic instrumentation, emergency locator transmitters, night vision devices, human implantable devices, as well as uses in the aerospace and defense programs. With this new technology comes the use of new solvent and electrolyte systems in the research, development, and production of lithium batteries. The goal is to enhance lithium battery technology with the use of non-hazardous materials. Therefore, the toxicity and health hazards associated with exposure to the solvents and electrolytes used in currentmore » lithium battery research and development is evaluated and described.« less

Electra-optical device including a nitrogen containing electrolyte

DOEpatents

Bates, John B.; Dudney, Nancy J.; Gruzalski, Greg R.; Luck, Christopher F.

1995-01-01

Described is a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between -15.degree. C. and 150.degree. C.

Structural design considerations for micromachined solid-oxide fuel cells

NASA Astrophysics Data System (ADS)

Srikar, V. T.; Turner, Kevin T.; Andrew Ie, Tze Yung; Spearing, S. Mark

Micromachined solid-oxide fuel cells (μSOFCs) are among a class of devices being investigated for portable power generation. Optimization of the performance and reliability of such devices requires robust, scale-dependent, design methodologies. In this first analysis, we consider the structural design of planar, electrolyte-supported, μSOFCs from the viewpoints of electrochemical performance, mechanical stability and reliability, and thermal behavior. The effect of electrolyte thickness on fuel cell performance is evaluated using a simple analytical model. Design diagrams that account explicitly for thermal and intrinsic residual stresses are presented to identify geometries that are resistant to fracture and buckling. Analysis of energy loss due to in-plane heat conduction highlights the importance of efficient thermal isolation in microscale fuel cell design.

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.

Integrating Desalination and Energy Storage using a Saltwater-based Hybrid Sodium-ion Supercapacitor.

PubMed

Guo, Zhaowei; Ma, Yuanyuan; Dong, Xiaoli; Hou, Mengyan; Wang, Yonggang; Xia, Yongyao

2018-06-11

Ever-increasing freshwater scarcity and energy crisis problems require efficient seawater desalination and energy storage technologies; however, each target is generally considered separately. Herein, a hybrid sodium-ion supercapacitor, involving a carbon-coated nano-NaTi 2 (PO 4 ) 3 -based battery anode and an activated-carbon-based capacitive cathode, is developed to combine desalination and energy storage in one device. On charge, the supercapacitor removes salt in a flowing saltwater electrolyte through Cl - electrochemical adsorption at the cathode and Na + intercalation at the anode. Discharge delivers useful electric energy and regenerates the electrodes. This supercapacitor can be used not only for energy storage with promising electrochemical performance (i.e., high power, high efficiency, and long cycle life), but also as a desalination device with desalination capacity of 146.8 mg g -1 , much higher than most reported capacitive and battery desalination devices. Finally, we demonstrate renewables to usable electric energy and desalted water through combining commercial photovoltaics and this hybrid supercapacitor. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bio-inspired materials for electrochemical devices

NASA Astrophysics Data System (ADS)

Pawlicka, A.; Firmino, A.; Sentanin, F.; Sabadini, R. C.; Jimenez, D. E. Q.; Jayme, C. C.; Mindroiu, M.; Zgarian, R. G.; Tihan, G. T.; Rau, I.; Silva, M. M.; Nogueira, A. F.; Kanicki, J.; Kajzar, F.

2015-10-01

Natural macromolecules are very promising row materials to be used in modern technology including security and defense. They are abundant in nature, easy to extract and possess biocompatibility and biodegradability properties. These materials can be modified throughout chemical or physical processes, and can be doped with lithium and rare earth salts, ionic liquids, organic and inorganic acids. In this communication samples of DNA and modified DNA were doped with Prussian Blue (PB), poly(ethylene dioxythiophene) (PEDOT), europium and erbium triflate and organic dyes such as Nile Blue (NB), Disperse Red 1 (DR1) and Disperse Orange 3 (DO3). The colored or colorless membranes were characterized by electrochemical and spectroscopic measurements, and they were applied in electrochromic devices (ECDs) and dye sensitized solar cells (DSSC). ECDs change the color under applied potential, so they can modulate the intensity of transmitted light of 15 to 35%. As the electrochromic materials, WO3 or Prussian blue (PB), are usually blue colored, the color change is from transparent to blue. DNA, and the complexes: DNA-CTMA, DNA-DODA and DNAPEDOT: PSS were also investigated as either hole carrier material (HTM) or polymer electrolyte in dye-sensitized solar cells (DSSC). The DNA-based samples as HTM in small DSSCs revealed a solar energy conversion efficiency of 0.56%. Polymer electrolytes of DNA-CTMA and DNA-DODA, both with 10 wt% of LiI/I2, applied in small DSSC, exhibited the efficiencies of 0.18 and 0.66%, respectively. The obtained results show that natural macromolecules-based membranes are not only environmentally friendly but are also promising materials to be investigated for several electrochemical devices. However, to obtain better performances more research is still needed.

Ionic Liquid Hybrid Electrolytes for Lithium-Ion Batteries: A Key Role of the Separator-Electrolyte Interface in Battery Electrochemistry.

PubMed

Huie, Matthew M; DiLeo, Roberta A; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

2015-06-10

Batteries are multicomponent systems where the theoretical voltage and stoichiometric electron transfer are defined by the electrochemically active anode and cathode materials. While the electrolyte may not be considered in stoichiometric electron-transfer calculations, it can be a critical factor determining the deliverable energy content of a battery, depending also on the use conditions. The development of ionic liquid (IL)-based electrolytes has been a research area of recent reports by other researchers, due, in part, to opportunities for an expanded high-voltage operating window and improved safety through the reduction of flammable solvent content. The study reported here encompasses a systematic investigation of the physical properties of IL-based hybrid electrolytes including quantitative characterization of the electrolyte-separator interface via contact-angle measurements. An inverse trend in the conductivity and wetting properties was observed for a series of IL-based electrolyte candidates. Test-cell measurements were undertaken to evaluate the electrolyte performance in the presence of functioning anode and cathode materials, where several promising IL-based hybrid electrolytes with performance comparable to that of conventional carbonate electrolytes were identified. The study revealed that the contact angle influenced the performance more significantly than the conductivity because the cells containing IL-tetrafluoroborate-based electrolytes with higher conductivity but poorer wetting showed significantly decreased performance relative to the cells containing IL-bis(trifluoromethanesulfonyl)imide electrolytes with lower conductivity but improved wetting properties. This work contributes to the development of new IL battery-based electrolyte systems with the potential to improve the deliverable energy content as well as safety of lithium-ion battery systems.

Efficient storage mechanisms for building better supercapacitors

NASA Astrophysics Data System (ADS)

Salanne, M.; Rotenberg, B.; Naoi, K.; Kaneko, K.; Taberna, P.-L.; Grey, C. P.; Dunn, B.; Simon, P.

2016-06-01

Supercapacitors are electrochemical energy storage devices that operate on the simple mechanism of adsorption of ions from an electrolyte on a high-surface-area electrode. Over the past decade, the performance of supercapacitors has greatly improved, as electrode materials have been tuned at the nanoscale and electrolytes have gained an active role, enabling more efficient storage mechanisms. In porous carbon materials with subnanometre pores, the desolvation of the ions leads to surprisingly high capacitances. Oxide materials store charge by surface redox reactions, leading to the pseudocapacitive effect. Understanding the physical mechanisms underlying charge storage in these materials is important for further development of supercapacitors. Here we review recent progress, from both in situ experiments and advanced simulation techniques, in understanding the charge storage mechanism in carbon- and oxide-based supercapacitors. We also discuss the challenges that still need to be addressed for building better supercapacitors.

Revealing the Charge Transport Mechanism in Polymerized Ionic Liquids: Insight from High Pressure Conductivity Studies

DOE PAGES

Wojnarowska, Zaneta; Feng, Hongbo; Diaz, Mariana; ...

2017-09-05

Polymerized ionic liquids (polyILs), composed mostly of organic ions covalently bonded to the polymer backbone and free counterions, are considered as an ideal electrolytes for various electrochemical devices, including fuel cells, supercapacitors and batteries. Despite large structural diversity of these systems, all of them reveal a universal but poorly understood feature - a charge transport faster than the segmental dynamics. Here, to address this issue, we have studied three novel polymer electrolyte membrane for fuel cells as well as four single-ion conductors including highly conductive siloxane-based polyIL. Our ambient and high pressure studies revealed fundamental differences in the conducting propertiesmore » of the examined systems. Finally, we demonstrate that the proposed methodology is a powerful tool to identify the charge transport mechanism in polyILs in general and thereby contribute to unraveling the microscopic nature of the decoupling phenomenon in these materials.« less

High Performance Variable Emittance Devices for Spacecraft Application Based on Conducting Polymers Coupled with Ionic Liquids

NASA Astrophysics Data System (ADS)

Chandrasekhar, Prasanna; Zay, Brian J.; Barbolt, Scott; Werner, Robert; Birur, Gajanana C.; Paris, Anthony

2009-03-01

This contribution describes the fabrication, function and performance of thin-film variable emittance electrochromic skins fabricated using poly(aniline) as the conducting polymer (CP), a long-chain polymeric dopant, and an ionic liquid as electrolyte. The ionic electrolyte allows operation in space vacuum without any seals. A unique, space-durable coating applied to the external surface of the skins drastically lowers the solar absorptance of the skins, such that in their dark (highly emissive) electrochromic state, it is no more than 0.44, whilst in their light electrochromic state, it is ca. 0.3. Data presented show tailorable, variations from 0.19 to 0.90, ∀(s)<0.3, and nearly indefinite cyclability. Extended thermal vacuum, atomic-O, micrometeoroid, VUV and other studies show excellent space durability. Performance of a doughnut-shaped skin designed for a specific micro-spacecraft is also described.

Light-assisted delithiation of lithium iron phosphate nanocrystals towards photo-rechargeable lithium ion batteries

PubMed Central

Paolella, Andrea; Faure, Cyril; Bertoni, Giovanni; Marras, Sergio; Guerfi, Abdelbast; Darwiche, Ali; Hovington, Pierre; Commarieu, Basile; Wang, Zhuoran; Prato, Mirko; Colombo, Massimo; Monaco, Simone; Zhu, Wen; Feng, Zimin; Vijh, Ashok; George, Chandramohan; Demopoulos, George P.; Armand, Michel; Zaghib, Karim

2017-01-01

Recently, intensive efforts are dedicated to convert and store the solar energy in a single device. Herein, dye-synthesized solar cell technology is combined with lithium-ion materials to investigate light-assisted battery charging. In particular we report the direct photo-oxidation of lithium iron phosphate nanocrystals in the presence of a dye as a hybrid photo-cathode in a two-electrode system, with lithium metal as anode and lithium hexafluorophosphate in carbonate-based electrolyte; a configuration corresponding to lithium ion battery charging. Dye-sensitization generates electron–hole pairs with the holes aiding the delithiation of lithium iron phosphate at the cathode and electrons utilized in the formation of a solid electrolyte interface at the anode via oxygen reduction. Lithium iron phosphate acts effectively as a reversible redox agent for the regeneration of the dye. Our findings provide possibilities in advancing the design principles for photo-rechargeable lithium ion batteries. PMID:28393912

Light-assisted delithiation of lithium iron phosphate nanocrystals towards photo-rechargeable lithium ion batteries

NASA Astrophysics Data System (ADS)

Paolella, Andrea; Faure, Cyril; Bertoni, Giovanni; Marras, Sergio; Guerfi, Abdelbast; Darwiche, Ali; Hovington, Pierre; Commarieu, Basile; Wang, Zhuoran; Prato, Mirko; Colombo, Massimo; Monaco, Simone; Zhu, Wen; Feng, Zimin; Vijh, Ashok; George, Chandramohan; Demopoulos, George P.; Armand, Michel; Zaghib, Karim

2017-04-01

Recently, intensive efforts are dedicated to convert and store the solar energy in a single device. Herein, dye-synthesized solar cell technology is combined with lithium-ion materials to investigate light-assisted battery charging. In particular we report the direct photo-oxidation of lithium iron phosphate nanocrystals in the presence of a dye as a hybrid photo-cathode in a two-electrode system, with lithium metal as anode and lithium hexafluorophosphate in carbonate-based electrolyte; a configuration corresponding to lithium ion battery charging. Dye-sensitization generates electron-hole pairs with the holes aiding the delithiation of lithium iron phosphate at the cathode and electrons utilized in the formation of a solid electrolyte interface at the anode via oxygen reduction. Lithium iron phosphate acts effectively as a reversible redox agent for the regeneration of the dye. Our findings provide possibilities in advancing the design principles for photo-rechargeable lithium ion batteries.

Light-assisted delithiation of lithium iron phosphate nanocrystals towards photo-rechargeable lithium ion batteries.

PubMed

Paolella, Andrea; Faure, Cyril; Bertoni, Giovanni; Marras, Sergio; Guerfi, Abdelbast; Darwiche, Ali; Hovington, Pierre; Commarieu, Basile; Wang, Zhuoran; Prato, Mirko; Colombo, Massimo; Monaco, Simone; Zhu, Wen; Feng, Zimin; Vijh, Ashok; George, Chandramohan; Demopoulos, George P; Armand, Michel; Zaghib, Karim

2017-04-10

Recently, intensive efforts are dedicated to convert and store the solar energy in a single device. Herein, dye-synthesized solar cell technology is combined with lithium-ion materials to investigate light-assisted battery charging. In particular we report the direct photo-oxidation of lithium iron phosphate nanocrystals in the presence of a dye as a hybrid photo-cathode in a two-electrode system, with lithium metal as anode and lithium hexafluorophosphate in carbonate-based electrolyte; a configuration corresponding to lithium ion battery charging. Dye-sensitization generates electron-hole pairs with the holes aiding the delithiation of lithium iron phosphate at the cathode and electrons utilized in the formation of a solid electrolyte interface at the anode via oxygen reduction. Lithium iron phosphate acts effectively as a reversible redox agent for the regeneration of the dye. Our findings provide possibilities in advancing the design principles for photo-rechargeable lithium ion batteries.

Revealing the Charge Transport Mechanism in Polymerized Ionic Liquids: Insight from High Pressure Conductivity Studies

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

Wojnarowska, Zaneta; Feng, Hongbo; Diaz, Mariana

Polymerized ionic liquids (polyILs), composed mostly of organic ions covalently bonded to the polymer backbone and free counterions, are considered as an ideal electrolytes for various electrochemical devices, including fuel cells, supercapacitors and batteries. Despite large structural diversity of these systems, all of them reveal a universal but poorly understood feature - a charge transport faster than the segmental dynamics. Here, to address this issue, we have studied three novel polymer electrolyte membrane for fuel cells as well as four single-ion conductors including highly conductive siloxane-based polyIL. Our ambient and high pressure studies revealed fundamental differences in the conducting propertiesmore » of the examined systems. Finally, we demonstrate that the proposed methodology is a powerful tool to identify the charge transport mechanism in polyILs in general and thereby contribute to unraveling the microscopic nature of the decoupling phenomenon in these materials.« less

Polymer electrolyte fuel cell mini power unit for portable application

NASA Astrophysics Data System (ADS)

Urbani, F.; Squadrito, G.; Barbera, O.; Giacoppo, G.; Passalacqua, E.; Zerbinati, O.

This paper describes the design, realisation and test of a power unit based on a polymer electrolyte fuel cell, operating at room temperature, for portable application. The device is composed of an home made air breathing fuel cell stack, a metal hydride tank for H 2 supply, a dc-dc converter for power output control and a fan for stack cooling. The stack is composed by 10 cells with an active surface of 25 cm 2 and produces a rated power of 15 W at 6 V and 2 A. The stack successfully runs with end-off fed hydrogen without appreciable performance degradation during the time. The final assembled system is able to generate 12 W at 9.5 V, and power a portable DVD player for 3 h in continuous. The power unit has collected about 100 h of operation without maintenance.

Phenyl boron-based compounds as anion receptors for non-aqueous battery electrolytes

DOEpatents

Lee, Hung Sui; Yang, Xiao-Qing; McBreen, James; Sun, Xuehui

2002-01-01

Novel fluorinated boronate-based compounds which act as anion receptors in non-aqueous battery electrolytes are provided. When added to non-aqueous battery electrolytes, the fluorinated boronate-based compounds of the invention enhance ionic conductivity and cation transference number of non-aqueous electrolytes. The fluorinated boronate-based anion receptors include different fluorinated alkyl and aryl groups.

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

Mattox, Tracy M.; Koo, Bonil; Garcia, Guillermo

An electrochromic device includes a nanostructured transition metal oxide bronze layer that includes one or more transition metal oxide and one or more dopant, a solid state electrolyte, and a counter electrode. The nanostructured transition metal oxide bronze selectively modulates transmittance of near-infrared (NIR) spectrum and visible spectrum radiation as a function of an applied voltage to the device.

The Use of Solid States Ionic Materials and Devices in Medical Applications

NASA Astrophysics Data System (ADS)

Linford, R. G.

2006-06-01

Electrolyte materials used in solid state polymer batteries can also be utilised in a special type of drug delivery system called an iontophoretic device. This review will describe the history, applications and limitations of iontophoretic and related systems and also the use of batteries and biofuel cells in medicine.

Band gap control using electric field of photonic gel cells fabricated with block copolymer and hydrogel.

PubMed

Lee, Sung Nam; Baek, Young Bin; Shin, Dong Myung

2014-08-01

Optical and electrical characteristics of the devices using photonic gel film and hydrogel electrolyte were studied. Poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) lamellar film with alternating hydrophobic block and hydrophilic polyelectrolyte block polymers (52 kg/mol-b-57 kg/mol) were prepared for the photonic gel. Poly(isobutylene-co-maleic acid) sodium salts were prepared for the hydrogel. This hydrogel fiber is common water swelling material and it owned ions for a device has conductivity. Photonic gel and hydrogel was spin coating onto Indium-tin-oxide (ITO) glass for make electric fields. The reflectance maximum wavelength of photonic crystal device shifted from 538 nm and reached to 557 nm, 585 nm and 604 nm during 30 min voltage applying time. The bandwidth variation was very limited. Loss of electrolyte was much less with hydrogel compared to the pure water. We can control color of hydrogel used photonic device by electric field with reasonable time range under moderate electric field by applying 2 V between two facing electrodes.

Microfluidic electrochemical device and process for chemical imaging and electrochemical analysis at the electrode-liquid interface in-situ

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

Yu, Xiao-Ying; Liu, Bingwen; Yang, Li

2016-03-01

A microfluidic electrochemical device and process are detailed that provide chemical imaging and electrochemical analysis under vacuum at the surface of the electrode-sample or electrode-liquid interface in-situ. The electrochemical device allows investigation of various surface layers including diffuse layers at selected depths populated with, e.g., adsorbed molecules in which chemical transformation in electrolyte solutions occurs.

Enhanced electrochemical performance of nickel-cobalt-oxide@reduced graphene oxide//activated carbon asymmetric supercapacitors by the addition of a redox-active electrolyte.

PubMed

Lamiel, Charmaine; Lee, Yong Rok; Cho, Moo Hwan; Tuma, Dirk; Shim, Jae-Jin

2017-12-01

Supercapacitors are an emerging energy-storage system with a wide range of potential applications. In this study, highly porous nickel-cobalt-oxide@reduced graphene oxide (Ni-Co-O@RGO-s) nanosheets were synthesized as an active material for supercapacitors using a surfactant-assisted microwave irradiation technique. The RGO-modified nanocomposite showed a larger specific area, better conductivity, and lower resistivity than the unmodified nanocomposite because the RGO facilitated faster ion diffusion/transport for improved redox activity. The synergistic effect of Ni-Co-O@RGO-s resulted in a high capacitance of 1903Fg -1 (at 0.8Ag -1 ) in a mixed KOH/redox active K 3 Fe(CN) 6 electrolyte. The asymmetric Ni-Co-O@RGO-s//AC supercapacitor device yielded a high energy density and power density of 39Whkg -1 and 7500Wkg -1 , respectively. The porous structure and combination of redox couples from both the electrode and electrolyte provided a highly synergistic effect, which improved the performance of the supercapacitor device. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of surface microstructure on electrochemical performance of garnet solid electrolytes.

PubMed

Cheng, Lei; Chen, Wei; Kunz, Martin; Persson, Kristin; Tamura, Nobumichi; Chen, Guoying; Doeff, Marca

2015-01-28

Cubic garnet phases based on Al-substituted Li7La3Zr2O12 (LLZO) have high ionic conductivities and exhibit good stability versus metallic lithium, making them of particular interest for use in next-generation rechargeable battery systems. However, high interfacial impedances have precluded their successful utilization in such devices until the present. Careful engineering of the surface microstructure, especially the grain boundaries, is critical to achieving low interfacial resistances and enabling long-term stable cycling with lithium metal. This study presents the fabrication of LLZO heterostructured solid electrolytes, which allowed direct correlation of surface microstructure with the electrochemical characteristics of the interface. Grain orientations and grain boundary distributions of samples with differing microstructures were mapped using high-resolution synchrotron polychromatic X-ray Laue microdiffraction. The electrochemical characteristics are strongly dependent upon surface microstructure, with small grained samples exhibiting much lower interfacial resistances and better cycling behavior than those with larger grain sizes. Low area specific resistances of 37 Ω cm(2) were achieved; low enough to ensure stable cycling with minimal polarization losses, thus removing a significant obstacle toward practical implementation of solid electrolytes in high energy density batteries.

Electrical, structural, thermal and electrochemical properties of corn starch-based biopolymer electrolytes.

PubMed

Liew, Chiam-Wen; Ramesh, S

2015-06-25

Biopolymer electrolytes containing corn starch, lithium hexafluorophosphate (LiPF6) and ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF6) are prepared by solution casting technique. Temperature dependence-ionic conductivity studies reveal Vogel-Tamman-Fulcher (VTF) relationship which is associated with free volume theory. Ionic liquid-based biopolymer electrolytes show lower glass transition temperature (Tg) than ionic liquid-free biopolymer electrolyte. X-ray diffraction (XRD) studies demonstrate higher amorphous region of ionic liquid-added biopolymer electrolytes. In addition, the potential stability window of the biopolymer electrolyte becomes wider and stable up to 2.9V. Conclusively, the fabricated electric double layer capacitor (EDLC) shows improved electrochemical performance upon addition of ionic liquid into the biopolymer electrolyte. The specific capacitance of EDLC based on ionic liquid-added polymer electrolyte is relatively higher than that of ionic liquid-free polymer electrolyte as depicted in cyclic voltammogram. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rechargeable Zn-air batteries: Progress in electrolyte development and cell configuration advancement

NASA Astrophysics Data System (ADS)

Xu, M.; Ivey, D. G.; Xie, Z.; Qu, W.

2015-06-01

Zn-air batteries, which are cost-effective and have high energy density, are promising energy storage devices for renewable energy and power sources for electric transportation. Nevertheless, limited charge and discharge cycles and low round-trip efficiency have long been barriers preventing the large-scale deployment of Zn-air batteries in the marketplace. Technology advancements for each battery component and the whole battery/cell assembly are being pursued, with some key milestones reached during the past 20 years. As an example, commercial Zn-air battery products with long lifetimes and high energy efficiencies are being considered for grid-scale energy storage and for automotive markets. In this review, we present our perspectives on improvements in Zn-air battery technology through the exploration and utilization of different electrolyte systems. Recent studies ranging from aqueous electrolytes to nonaqueous electrolytes, including solid polymer electrolytes and ionic liquids, as well as hybrid electrolyte systems adopted in Zn-air batteries have been evaluated. Understanding the benefits and drawbacks of each electrolyte, as well as the fundamental electrochemistry of Zn and air electrodes in different electrolytes, are the focus of this paper. Further consideration is given to detailed Zn-air battery configurations that have been studied and applied in commercial or nearing commercial products, with the purpose of exposing state-of-the-art technology innovations and providing insights into future advancements.

Printed energy storage devices by integration of electrodes and separators into single sheets of paper

NASA Astrophysics Data System (ADS)

Hu, Liangbing; Wu, Hui; Cui, Yi

2010-05-01

We report carbon nanotube thin film-based supercapacitors fabricated with printing methods, where electrodes and separators are integrated into single sheets of commercial paper. Carbon nanotube films are easily printed with Meyer rod coating or ink-jet printing onto a paper substrate due to the excellent ink absorption of paper. A specific capacity of 33 F/g at a high specific power of 250 000 W/kg is achieved with an organic electrolyte. Such a lightweight paper-based supercapacitor could be used to power paper electronics such as transistors or displays.

Transport and spectroscopic studies of liquid and polymer electrolytes

NASA Astrophysics Data System (ADS)

Bopege, Dharshani Nimali

Liquid and polymer electrolytes are interesting and important materials to study as they are used in Li rechargeable batteries and other electrochemical devices. It is essential to investigate the fundamental properties of electrolytes such as ionic conductivity, diffusion, and ionic association to enhance battery performance in different battery markets. This dissertation mainly focuses on the temperature-dependent charge and mass transport processes and ionic association of different electrolyte systems. Impedance spectroscopy and pulsed field gradient nuclear magnetic resonance spectroscopy were used to measure the ionic conductivity and diffusion coefficients of ketone and acetate based liquid electrolytes. In this study, charge and mass transport in non-aqueous liquid electrolytes have been viewed from an entirely different perspective by introducing the compensated Arrhenius formalism. Here, the conductivity and diffusion coefficient are written as an Arrhenius-like expression with a temperature-dependent static dielectric constant dependence in the exponential prefactor. The compensated Arrhenius formalism reported in this dissertation very accurately describes temperature-dependent conductivity data for acetate and ketone-based electrolytes as well as temperature-dependent diffusion data of pure solvents. We found that calculated average activation energies of ketone-based electrolytes are close to each other for both conductivity and diffusion data (in the range 24-26 kJ/mol). Also, this study shows that average activation energies of acetate-based electrolytes are higher than those for the ketone systems (in the range 33-37 kJ/mol). Further, we observed higher dielectric constants and ionic conductivities for both dilute and concentrated ketone solutions with temperature. Vibrational spectroscopy (Infrared and Raman) was used to probe intermolecular interactions in both polymer and liquid electrolytes, particularly those which contain lithium trifluoromethanesulfonate, LiCF3SO3, abbreviated here as lithium triflate(LiTf). The molar absorption coefficients of nus(SO3), deltas(CF3), and deltas(SO3) vibrational modes of triflate anion in the LiTf-2-pentanone system were found to be 6708+/-89, 5182+/-62, and 189+/-2 kg mol-1 cm-1, respectively using Beer-Lambert law. Our results show that there is strong absorption by nu s(SO3) mode and weak absorption by deltas(CF 3) mode. Also, the absorptivity of each mode is independent of the ionic association with Li ions. This work allows for the direct quantitative comparison of calculated concentrations in different samples and different experimental conditions. In addition, this dissertation reports the temperature-dependent vibrational spectroscopic studies of pure poly(ethylene oxide) and LiTf-poly(ethylene oxide) complexes. A significant portion of this dissertation focuses on crystallographic studies of ketone-salt (LiTf:2-pentanone and NaTf:2-hexanone) and amine-acid (diethyleneamine: H3PO4, N,N'-dimethylethylenediamine:H 3PO4, and piperazine:H3PO4) systems. Here, sodium trifluoromethanesulfonate, NaCF3SO3 is abbreviated as NaTf. As model compounds, these systems provide valuable information about ion-ion interactions, which are helpful for understanding complex polymer systems. During this study, five crystal structures were solved using single X-ray diffractometry, and their vibrational modes were studied in the mid-infrared region. In the secondary amine/phosphoric acid systems, the nature of hydrogen-bonding network was examined.

A Novel Phase-Transformation Activation Process toward Ni-Mn-O Nanoprism Arrays for 2.4 V Ultrahigh-Voltage Aqueous Supercapacitors.

PubMed

Zuo, Wenhua; Xie, Chaoyue; Xu, Pan; Li, Yuanyuan; Liu, Jinping

2017-09-01

One of the key challenges of aqueous supercapacitors is the relatively low voltage (0.8-2.0 V), which significantly limits the energy density and feasibility of practical applications of the device. Herein, this study reports a novel Ni-Mn-O solid-solution cathode to widen the supercapacitor device voltage, which can potentially suppress the oxygen evolution reaction and thus be operated stably within a quite wide potential window of 0-1.4 V (vs saturated calomel electrode) after a simple but unique phase-transformation electrochemical activation. The solid-solution structure is designed with an ordered array architecture and in situ nanocarbon modification to promote the charge/mass transfer kinetics. By paring with commercial activated carbon anode, an ultrahigh voltage asymmetric supercapacitor in neutral aqueous LiCl electrolyte is assembled (2.4 V; among the highest for single-cell supercapacitors). Moreover, by using a polyvinyl alcohol (PVA)-LiCl electrolyte, a 2.4 V hydrogel supercapacitor is further developed with an excellent Coulombic efficiency, good rate capability, and remarkable cycle life (>5000 cycles; 95.5% capacity retention). Only one cell can power the light-emitting diode indicator brightly. The resulting maximum volumetric energy density is 4.72 mWh cm -3 , which is much superior to previous thin-film manganese-oxide-based supercapacitors and even battery-supercapacitor hybrid devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A three-dimensional reticulate CNT-aerogel for a high mechanical flexibility fiber supercapacitor.

PubMed

Li, Yong; Kang, Zhuo; Yan, Xiaoqin; Cao, Shiyao; Li, Minghua; Guo, Yan; Huan, Yahuan; Wen, Xiaosong; Zhang, Yue

2018-05-17

In recent years, the rapid development of portable and wearable electronic products has promoted the prosperity of fiber supercapacitors (FSCs), which serve as flexible and lightweight energy supply devices. However, research on FSCs is still in its infancy and the energy density of FSCs is far below the level of lithium-ion batteries. Here, we report a facile method to prepare a novel fibrous CNT-aerogel by electrochemical activation and freeze-drying. The fibrous CNT-aerogel electrode possesses a large specific surface area, high mechanical strength, excellent electrical conductivity, as well as a high specific capacitance of 160.8 F g-1 at 0.5 mA and long cycling stability. Then we assembled a non-faradaic FSC based on a fibrous CNT-aerogel as the electrode and a P(VDF-HFP)/EMIMBF4 ionogel as the electrolyte. The introduction of the ionogel electrolyte increases the operating voltage of the FSC to 3 V, and makes the device combine the intrinsic high power density (27.3 kW kg-1) of non-faradaic SCs with an ultrahigh energy density of 29.6 W h kg-1. More importantly, the assembled FSCs show excellent flexibility and bending-stability, and can still operate normally within a wide working temperature window (0-80 °C). The outstanding electrochemical performance and the mechanical/thermal stability indicate that the assembled FSC device is a promising power source for flexible electronics.

Enhanced cycling performance of a Li metal anode in a dimethylsulfoxide-based electrolyte using highly concentrated lithium salt for a lithium-oxygen battery

NASA Astrophysics Data System (ADS)

Togasaki, Norihiro; Momma, Toshiyuki; Osaka, Tetsuya

2016-03-01

Stable charge-discharge cycling behavior for a lithium metal anode in a dimethylsulfoxide (DMSO)-based electrolyte is strongly desired of lithium-oxygen batteries, because the Li anode is rapidly exhausted as a result of side reactions during cycling in the DMSO solution. Herein, we report a novel electrolyte design for enhancing the cycling performance of Li anodes by using a highly concentrated DMSO-based electrolyte with a specific Li salt. Lithium nitrate (LiNO3), which forms an inorganic compound (Li2O) instead of a soluble product (Li2S) on a lithium surface, exhibits a >20% higher coulombic efficiency than lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium perchlorate, regardless of the loading current density. Moreover, the stable cycling of Li anodes in DMSO-based electrolytes depends critically on the salt concentration. The highly concentrated electrolyte 4.0 M LiNO3/DMSO displays enhanced and stable cycling performance comparable to that of carbonate-based electrolytes, which had not previously been achieved. We suppose this enhancement is due to the absence of free DMSO solvent in the electrolyte and the promotion of the desolvation of Li ions on the solid electrolyte interphase surface, both being consequences of the unique structure of the electrolyte.

High Voltage LiNi0.5Mn1.5O4/Li4Ti5O12 Lithium Ion Cells at Elevated Temperatures: Carbonate- versus Ionic Liquid-Based Electrolytes.

PubMed

Cao, Xia; He, Xin; Wang, Jun; Liu, Haidong; Röser, Stephan; Rad, Babak Rezaei; Evertz, Marco; Streipert, Benjamin; Li, Jie; Wagner, Ralf; Winter, Martin; Cekic-Laskovic, Isidora

2016-10-05

Thanks to its high operating voltage, the LiNi 0.5 Mn 1.5 O 4 (LNMO) spinel represents a promising next-generation cathode material candidate for Lithium ion batteries. However, LNMO-based full-cells with organic carbonate solvent electrolytes suffer from severe capacity fading issues, associated with electrolyte decomposition and concurrent degradative reactions at the electrode/electrolyte interface, especially at elevated temperatures. As promising alternatives, two selected LiTFSI/pyrrolidinium bis(trifluoromethane-sulfonyl)imide room temperature ionic liquid (RTIL) based electrolytes with inherent thermal stability were investigated in this work. Linear sweep voltammetry (LSV) profiles of the investigated LiTFSI/RTIL electrolytes display much higher oxidative stability compared to the state-of-the-art LiPF 6 /organic carbonate based electrolyte at elevated temperatures. Cycling performance of the LNMO/Li 4 Ti 5 O 12 (LTO) full-cells with LiTFSI/RTIL electrolytes reveals remarkable improvements with respect to capacity retention and Coulombic efficiency. Scanning electron microscopy (SEM) images and X-ray diffraction (XRD) patterns indicate maintained pristine morphology and structure of LNMO particles after 50 cycles at 0.5C. The investigated LiTFSI/RTIL based electrolytes outperform the LiPF 6 /organic carbonate-based electrolyte in terms of cycling performance in LNMO/LTO full-cells at elevated temperatures.

A system using solid ceramic oxygen electrolyte cells to measure oxygen fugacities in gas-mixing systems

NASA Technical Reports Server (NTRS)

Williams, R. J.; Mullins, O.

1976-01-01

Details are given for the construction and operation of a 101.3 kN/sq m (1 atmosphere) redox control system. A solid ceramic oxygen electrolyte cell is used to monitor the oxygen fugacity in the furnace. The system consists of a vertical quench, gas mixing furnace with heads designed for mounting the electrolyte cell and with facilities for inserting and removing the samples. The system also contains the high input impedance electronics necessary for measurements, a simplified version of a gas mixing apparatus, and devices for experiments under controlled rates of change relative to temperature and redox state. The calibration and maintenance of the system are discussed.

Composite electrode/electrolyte structure

DOEpatents

Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

2004-01-27

Provided is an electrode fabricated from highly electronically conductive materials such as metals, metal alloys, or electronically conductive ceramics. The electronic conductivity of the electrode substrate is maximized. Onto this electrode in the green state, a green ionic (e.g., electrolyte) film is deposited and the assembly is co-fired at a temperature suitable to fully densify the film while the substrate retains porosity. Subsequently, a catalytic material is added to the electrode structure by infiltration of a metal salt and subsequent low temperature firing. The invention allows for an electrode with high electronic conductivity and sufficient catalytic activity to achieve high power density in ionic (electrochemical) devices such as fuel cells and electrolytic gas separation systems.

JSC systems using solid ceramic oxygen electrolyte cells to measure oxygen fugacites in gas-mixing systems

NASA Technical Reports Server (NTRS)

Williams, R. J.; Mullins, O.

1981-01-01

Details are given for the construction and operation of a 101.3 KN/sq meter (1 atmosphere) redox control system. A solid ceramic oxygen electrolyte cell is used to monitor the oxygen fugacity in the furnace. The system consists of a vertical quench gas mixing furnace with heads designed for mounting the electrolyte cell and with facilities for inserting and removing the samples, a simplified version of a gas mixing apparatus, and devices for experiments under controlled rates of change of temperature. A thermogravimetric analysis system employing these techniques of redox control and measurement is also described. The calibration and maintenance of the system are discussed.

Unique Three-Dimensional InP Nanopore Arrays for Improved Photoelectrochemical Hydrogen Production.

PubMed

Li, Qiang; Zheng, Maojun; Ma, Liguo; Zhong, Miao; Zhu, Changqing; Zhang, Bin; Wang, Faze; Song, Jingnan; Ma, Li; Shen, Wenzhong

2016-08-31

Ordered three-dimensional (3D) nanostructure arrays hold promise for high-performance energy harvesting and storage devices. Here, we report the fabrication of InP nanopore arrays (NPs) in unique 3D architectures with excellent light trapping characteristic and large surface areas for use as highly active photoelectrodes in photoelectrochemical (PEC) hydrogen evolution devices. The ordered 3D NPs were scalably synthesized by a facile two-step etching process of (1) anodic etching of InP in neutral 3 M NaCl electrolytes to realize nanoporous structures and (2) wet chemical etching in HCl/H3PO4 (volume ratio of 1:3) solutions for removing the remaining top irregular layer. Importantly, we demonstrated that the use of neutral electrolyte of NaCl instead of other solutions, such as HCl, in anodic etching of InP can significantly passivate the surface states of 3D NPs. As a result, the maximum photoconversion efficiency obtained with ∼15.7 μm thick 3D NPs was 0.95%, which was 7.3 and 1.4 times higher than that of planar and 2D NPs. Electrochemical impedance spectroscopy and photoluminescence analyses further clarified that the improved PEC performance was attributed to the enhanced charge transfer across 3D NPs/electrolyte interfaces, the improved charge separation at 3D NPs/electrolyte junction, and the increased PEC active surface areas with our unique 3D NP arrays.

Electrolyte additives for lithium metal anodes and rechargeable lithium metal batteries: progresses and perspectives.

PubMed

Zhang, Heng; Eshetu, Gebrekidan Gebresilassie; Judez, Xabier; Li, Chunmei; Rodriguez-Martínez, Lide M; Armand, Michel

2018-02-14

Lithium metal (Li°) - based rechargeable batteries (LMBs), such as Li° anode vs. intercalation and/or conversion type cathode batteries, lithium-sulphur (Li-S), and lithium-oxygen (O2)/air (Li-O2/air) are becoming increasingly important for electrifying the modern transportation system, enabling sustainable mobility in the near future. Though some rechargeable LMBs batteries (e.g., Li°/LiFePO4 batteries from Bolloré Bluecar®, Li-S batteries from OXIS Energy and Sion Power) are already commercially viable in niche applications, their large-scale deployment is still hampered due to the existence of a number of formidable challenges, including lithium dendrite growth, electrolyte instability towards high voltage intercalation type cathode, poor electronic and ionic conductivities of sulphur (S8) and O2, as well as their corresponding reduction products (e.g., Li2S and Li2O), dissolution and shuttling of polysulphide (PS) intermediates etc. This ultimately results in short cycle life, low coulombic/energy efficiency, poor safety, and a high self-discharge rate. Among other mitigating strategies, the use of electrolyte additives is considered as one of the most economical, and effective approach for circumventing these dilemmas. Set out to offer an in-depth insight into the rapidly growing research on the account of electrolyte additives for rechargeable LMBs, this review presents an overview of the various functional additives, that are being applied in Li-anode/intercalation cathode-based, Li-S and Li-O2 batteries. This review is believed to assess the status quo of the research and thereby arouse new thoughts and opportunities, opening new avenues for the practical realization of these appealing devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supercapacitors specialities - Materials review

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

Obreja, Vasile V. N.

The electrode material is a key component for supercapacitor cell performance. As it is known, performance comparison of commercial available batteries and supercapacitors reveals significantly lower energy storage capability for supercapacitor devices. The energy density of commercial supercapacitor cells is limited to 10 Wh/kg whereas that of common lead acid batteries reaches 35-40 Wh/kg. For lithium ion batteries a value higher than 100 Wh/kg is easily available. Nevertheless, supercapacitors also known as ultracapacitors or electrochemical capacitors have other advantages in comparison with batteries. As a consequence, many efforts have been made in the last years to increase the storage energymore » density of electrochemical capacitors. A lot of results from published work (research and review papers, patents and reports) are available at this time. The purpose of this review is a presentation of the progress to date for the use of new materials and approaches for supercapacitor electrodes, with focus on the energy storage capability for practical applications. Many reported results refer to nanostructured carbon based materials and the related composites, used for the manufacture of experimental electrodes. A specific capacitance and a specific energy are seldom revealed as the main result of the performed investigation. Thus for nanoprous (activated) carbon based electrodes a specific capacitance up to 200-220 F/g is mentioned for organic electrolyte, whereas for aqueous electrolyte, the value is limited to 400-500 F/g. Significant contribution to specific capacitance is possible from fast faradaic reactions at the electrode-electrolyte interface in addition to the electric double layer effect. The corresponding energy density is limited to 30-50 Wh/kg for organic electrolyte and to 12-17 Wh/kg for aqueous electrolyte. However such performance indicators are given only for the carbon material used in electrodes. For a supercapacitor cell, where two electrodes and also other materials for cell assembling and packaging are used, the above mentioned values have to be divided by a factor higher than four. As a consequence, the specific energy of a prototype cell, hardly could exceed 10 Wh/kg because of difficulties with the existing manufacturing technology. Graphene based materials and carbon nanotubes and different composites have been used in many experiments reported in the last years. Nevertheless in spite of the outstanding properties of these materials, significant increase of the specific capacitance or of the specific energy in comparison with activated or nanoporous carbon is not achieved. Use of redox materials as metal oxides or conducting polymers in combination with different nanostructured carbon materials (nanocomposite electrodes) has been found to contribute to further increase of the specific capacitance or of the specific energy. Nevertheless, few results are reported for practical cells with such materials. Many results are reported only for a three electrode system and significant difference is possible when the electrode is used in a practical supercapacitor cell. Further improvement in the electrode manufacture and more experiments with supercapacitor cells with the known electrochemical storage materials are required. Device prototypes and commercial products with an energy density towards 15-20 Wh/kg could be realized. These may be a milestone for further supercapacitor device research and development, to narrow the storage energy gap between batteries and supercapacitors.« less

Supercapacitors specialities - Materials review

NASA Astrophysics Data System (ADS)

Obreja, Vasile V. N.

2014-06-01

The electrode material is a key component for supercapacitor cell performance. As it is known, performance comparison of commercial available batteries and supercapacitors reveals significantly lower energy storage capability for supercapacitor devices. The energy density of commercial supercapacitor cells is limited to 10 Wh/kg whereas that of common lead acid batteries reaches 35-40 Wh/kg. For lithium ion batteries a value higher than 100 Wh/kg is easily available. Nevertheless, supercapacitors also known as ultracapacitors or electrochemical capacitors have other advantages in comparison with batteries. As a consequence, many efforts have been made in the last years to increase the storage energy density of electrochemical capacitors. A lot of results from published work (research and review papers, patents and reports) are available at this time. The purpose of this review is a presentation of the progress to date for the use of new materials and approaches for supercapacitor electrodes, with focus on the energy storage capability for practical applications. Many reported results refer to nanostructured carbon based materials and the related composites, used for the manufacture of experimental electrodes. A specific capacitance and a specific energy are seldom revealed as the main result of the performed investigation. Thus for nanoprous (activated) carbon based electrodes a specific capacitance up to 200-220 F/g is mentioned for organic electrolyte, whereas for aqueous electrolyte, the value is limited to 400-500 F/g. Significant contribution to specific capacitance is possible from fast faradaic reactions at the electrode-electrolyte interface in addition to the electric double layer effect. The corresponding energy density is limited to 30-50 Wh/kg for organic electrolyte and to 12-17 Wh/kg for aqueous electrolyte. However such performance indicators are given only for the carbon material used in electrodes. For a supercapacitor cell, where two electrodes and also other materials for cell assembling and packaging are used, the above mentioned values have to be divided by a factor higher than four. As a consequence, the specific energy of a prototype cell, hardly could exceed 10 Wh/kg because of difficulties with the existing manufacturing technology. Graphene based materials and carbon nanotubes and different composites have been used in many experiments reported in the last years. Nevertheless in spite of the outstanding properties of these materials, significant increase of the specific capacitance or of the specific energy in comparison with activated or nanoporous carbon is not achieved. Use of redox materials as metal oxides or conducting polymers in combination with different nanostructured carbon materials (nanocomposite electrodes) has been found to contribute to further increase of the specific capacitance or of the specific energy. Nevertheless, few results are reported for practical cells with such materials. Many results are reported only for a three electrode system and significant difference is possible when the electrode is used in a practical supercapacitor cell. Further improvement in the electrode manufacture and more experiments with supercapacitor cells with the known electrochemical storage materials are required. Device prototypes and commercial products with an energy density towards 15-20 Wh/kg could be realized. These may be a milestone for further supercapacitor device research and development, to narrow the storage energy gap between batteries and supercapacitors.

Sodium heat engine electrical feedthrough

DOEpatents

Weber, N.

1985-03-19

A thermoelectric generator device which converts heat energy to electrical energy is disclosed. An alkali metal is used with a solid electrolyte and a hermetically sealed feedthrough structure. 4 figs.

Method for improving the durability of ion insertion materials

DOEpatents

Lee, Se-Hee; Tracy, C. Edwin; Cheong, Hyeonsik M.

2002-01-01

The invention provides a method of protecting an ion insertion material from the degradative effects of a liquid or gel-type electrolyte material by disposing a protective, solid ion conducting, electrically insulating, layer between the ion insertion layer and the liquid or gel-type electrolyte material. The invention further provides liquid or gel-type electrochemical cells having improved durability having a pair of electrodes, a pair of ion insertion layers sandwiched between the pair of electrodes, a pair of solid ion conducting layers sandwiched between the ion insertion layers, and a liquid or gel-type electrolyte material disposed between the solid ion conducting layers, where the solid ion conducting layer minimizes or prevents degradation of the faces of the ion insertion materials facing the liquid or gel-type electrolyte material. Electrochemical cells of this invention having increased durability include secondary lithium batteries and electrochromic devices.

Design and synthesis of the superionic conductor Na10SnP2S12

NASA Astrophysics Data System (ADS)

Richards, William D.; Tsujimura, Tomoyuki; Miara, Lincoln J.; Wang, Yan; Kim, Jae Chul; Ong, Shyue Ping; Uechi, Ichiro; Suzuki, Naoki; Ceder, Gerbrand

2016-03-01

Sodium-ion batteries are emerging as candidates for large-scale energy storage due to their low cost and the wide variety of cathode materials available. As battery size and adoption in critical applications increases, safety concerns are resurfacing due to the inherent flammability of organic electrolytes currently in use in both lithium and sodium battery chemistries. Development of solid-state batteries with ionic electrolytes eliminates this concern, while also allowing novel device architectures and potentially improving cycle life. Here we report the computation-assisted discovery and synthesis of a high-performance solid-state electrolyte material: Na10SnP2S12, with room temperature ionic conductivity of 0.4 mS cm-1 rivalling the conductivity of the best sodium sulfide solid electrolytes to date. We also computationally investigate the variants of this compound where tin is substituted by germanium or silicon and find that the latter may achieve even higher conductivity.

Design and synthesis of the superionic conductor Na10SnP2S12.

PubMed

Richards, William D; Tsujimura, Tomoyuki; Miara, Lincoln J; Wang, Yan; Kim, Jae Chul; Ong, Shyue Ping; Uechi, Ichiro; Suzuki, Naoki; Ceder, Gerbrand

2016-03-17

Sodium-ion batteries are emerging as candidates for large-scale energy storage due to their low cost and the wide variety of cathode materials available. As battery size and adoption in critical applications increases, safety concerns are resurfacing due to the inherent flammability of organic electrolytes currently in use in both lithium and sodium battery chemistries. Development of solid-state batteries with ionic electrolytes eliminates this concern, while also allowing novel device architectures and potentially improving cycle life. Here we report the computation-assisted discovery and synthesis of a high-performance solid-state electrolyte material: Na10SnP2S12, with room temperature ionic conductivity of 0.4 mS cm(-1) rivalling the conductivity of the best sodium sulfide solid electrolytes to date. We also computationally investigate the variants of this compound where tin is substituted by germanium or silicon and find that the latter may achieve even higher conductivity.