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Sample records for air electrode material

  1. Method of making an air electrode material having controlled sinterability

    DOEpatents

    Vasilow, Theodore R.; Kuo, Lewis J. H.; Ruka, Roswell J.

    1994-01-01

    A tubular, porous ceramic electrode structure (3) is made from the sintered admixture of doped lanthanum manganite and an additive containing cerium where a solid electrolyte (4), substantially surrounds the air electrode, and a porous outer fuel electrode (7) substantially surrounds the electrolyte, to form a fuel cell (1).

  2. Method of making an air electrode material having controlled sinterability

    DOEpatents

    Vasilow, T.R.; Kuo, L.J.H.; Ruka, R.J.

    1994-08-30

    A tubular, porous ceramic electrode structure is made from the sintered admixture of doped lanthanum manganite and an additive containing cerium where a solid electrolyte, substantially surrounds the air electrode, and a porous outer fuel electrode substantially surrounds the electrolyte, to form a fuel cell. 2 figs.

  3. Novel air electrode for metal-air battery with new carbon material and method of making same

    DOEpatents

    Ross, P.N. Jr.

    1988-06-21

    This invention relates to a rechargeable battery or fuel cell. More particularly, this invention relates to a novel air electrode comprising a new carbon electrode support material and a method of making same. 3 figs.

  4. PEDOT:PSS as multi-functional composite material for enhanced Li-air-battery air electrodes

    PubMed Central

    Yoon, Dae Ho; Yoon, Seon Hye; Ryu, Kwang-Sun; Park, Yong Joon

    2016-01-01

    We propose PEDOT:PSS as a multi-functional composite material for an enhanced Li-air-battery air electrode. The PEDOT:PSS layer was coated on the surface of carbon (graphene) using simple method. A electrode containing PEDOT:PSS-coated graphene (PEDOT electrode) could be prepared without binder (such as PVDF) because of high adhesion of PEDOT:PSS. PEDOT electrode presented considerable discharge and charge capacity at all current densities. These results shows that PEDOT:PSS acts as a redox reaction matrix and conducting binder in the air electrode. Moreover, after cycling, the accumulation of reaction products due to side reaction in the electrode was significantly reduced through the use of PEDOT:PSS. This implies that PEDOT:PSS coating layer can suppress the undesirable side reactions between the carbon and electrolyte (and/or Li2O2), which causes enhanced Li-air cell cyclic performance. PMID:26813852

  5. Novel air electrode for metal-air battery with new carbon material and method of making same

    DOEpatents

    Ross, Jr., Philip N.

    1990-01-01

    A novel carbonaceous electrode support material is disclosed characterized by a corrosion rate of 0.03 wt. %/hour or less when measured a5 550 millivolts vs. a Hg/HgO electrode in a 30 wt. % KOH electrolyte a5 30.degree. C. The electrode support material comprises a preselected carbon black material which has been heat-treated by heating the material to a temperature of from about 2500.degree. to about 3000.degree. C. over a period of from about 1 to about 5 hours in an inert atmosphere and then maintaining the preselected carbon black material at this temperature for a period of at least about 1 hour, and preferably about 2 hours, in the inert atmosphere. A carbonaceous electrode suitable for use as an air electrode in a metal-air cell may be made from the electrode support material by shaping and forming it into a catalyst support and then impregnating it with a catalytically active material capable of catalyzing the reaction with oxygen at the air electrode of metal-air cell.

  6. Low cost stable air electrode material for high temperature solid oxide electrolyte electrochemical cells

    DOEpatents

    Kuo, Lewis J. H.; Singh, Prabhakar; Ruka, Roswell J.; Vasilow, Theodore R.; Bratton, Raymond J.

    1997-01-01

    A low cost, lanthanide-substituted, dimensionally and thermally stable, gas permeable, electrically conductive, porous ceramic air electrode composition of lanthanide-substituted doped lanthanum manganite is provided which is used as the cathode in high temperature, solid oxide electrolyte fuel cells and generators. The air electrode composition of this invention has a much lower fabrication cost as a result of using a lower cost lanthanide mixture, either a natural mixture or an unfinished lanthanide concentrate obtained from a natural mixture subjected to incomplete purification, as the raw material in place of part or all of the higher cost individual lanthanum. The mixed lanthanide primarily contains a mixture of at least La, Ce, Pr, and Nd, or at least La, Ce, Pr, Nd and Sm in its lanthanide content, but can also include minor amounts of other lanthanides and trace impurities. The use of lanthanides in place of some or all of the lanthanum also increases the dimensional stability of the air electrode. This low cost air electrode can be fabricated as a cathode for use in high temperature, solid oxide fuel cells and generators.

  7. Low cost stable air electrode material for high temperature solid oxide electrolyte electrochemical cells

    DOEpatents

    Kuo, L.J.H.; Singh, P.; Ruka, R.J.; Vasilow, T.R.; Bratton, R.J.

    1997-11-11

    A low cost, lanthanide-substituted, dimensionally and thermally stable, gas permeable, electrically conductive, porous ceramic air electrode composition of lanthanide-substituted doped lanthanum manganite is provided which is used as the cathode in high temperature, solid oxide electrolyte fuel cells and generators. The air electrode composition of this invention has a much lower fabrication cost as a result of using a lower cost lanthanide mixture, either a natural mixture or an unfinished lanthanide concentrate obtained from a natural mixture subjected to incomplete purification, as the raw material in place of part or all of the higher cost individual lanthanum. The mixed lanthanide primarily contains a mixture of at least La, Ce, Pr, and Nd, or at least La, Ce, Pr, Nd and Sm in its lanthanide content, but can also include minor amounts of other lanthanides and trace impurities. The use of lanthanides in place of some or all of the lanthanum also increases the dimensional stability of the air electrode. This low cost air electrode can be fabricated as a cathode for use in high temperature, solid oxide fuel cells and generators. 4 figs.

  8. Solid oxide fuel cells, and air electrode and electrical interconnection materials therefor

    DOEpatents

    Bates, J.L.

    1992-09-01

    In one aspect of the invention, an air electrode material for a solid oxide fuel cell comprises Y[sub 1[minus]a]Q[sub a]MnO[sub 3], where Q is selected from the group consisting of Ca and Sr or mixtures thereof and a' is from 0.1 to 0.8. Preferably, a' is from 0.4 to 0.7. In another aspect of the invention, an electrical interconnection material for a solid oxide fuel cell comprises Y[sub 1[minus]b]Ca[sub b]Cr[sub 1[minus]c]Al[sub c]O[sub 3], where b' is from 0.1 to 0.6 and c' is from 0 to 9.3. Preferably, b' is from 0.3 to 0.5 and c' is from 0.05 to 0.1. A composite solid oxide electrochemical fuel cell incorporating these materials comprises: a solid oxide air electrode and an adjacent solid oxide electrical interconnection which commonly include the cation Y, the air electrode comprising Y[sub 1[minus]a]Q[sub a]MnO[sub 3], where Q is selected from the group consisting of Ca and Sr or mixtures thereof and a' is from 0.1 to 0.8, the electrical interconnection comprising Y[sub 1[minus]b]Ca[sub b]Cr[sub 1[minus]c]Al[sub c]O[sub 3], where b' is from 0.1 to 0.6 and c' is from 0.0 to 0.3; a yttrium stabilized solid electrolyte comprising (1[minus]d)ZrO[sub 2]-(d)Y[sub 2]O[sub 3] where d' is from 0.06 to 0.5; and a solid fuel electrode comprising X-ZrO[sub 2], where X' is an elemental metal. 5 figs.

  9. Solid oxide fuel cells, and air electrode and electrical interconnection materials therefor

    DOEpatents

    Bates, J. Lambert

    1992-01-01

    In one aspect of the invention, an air electrode material for a solid oxide fuel cell comprises Y.sub.1-a Q.sub.a MnO.sub.3, where "Q" is selected from the group consisting of Ca and Sr or mixtures thereof and "a" is from 0.1 to 0.8. Preferably, "a" is from 0.4 to 0.7. In another aspect of the invention, an electrical interconnection material for a solid oxide fuel cell comprises Y.sub.1-b Ca.sub.b Cr.sub.1-c Al.sub.c O.sub.3, where "b" is from 0.1 to 0.6 and "c" is from 0 to 9.3. Preferably, "b" is from 0.3 to 0.5 and "c" is from 0.05 to 0.1. A composite solid oxide electrochemical fuel cell incorporating these materials comprises: a solid oxide air electrode and an adjacent solid oxide electrical interconnection which commonly include the cation Y, the air electrode comprising Y.sub.1-a Q.sub.a MnO.sub.3, where "Q" is selected from the group consisting of Ca and Sr or mixtures thereof and "a" is from 0.1 to 0.8, the electrical interconnection comprising Y.sub.1-b Ca.sub.b Cr.sub.1-c Al.sub.c O.sub.3, where "b" is from 0.1 to 0.6 and "c" is from 0.0 to 0.3; a yttrium stabilized solid electrolyte comprising (1-d)ZrO.sub.2 -(d)Y.sub.2 O.sub.3 where "d" is from 0.06 to 0.5; and a solid fuel electrode comprising X-ZrO.sub.2, where "X" is an elemental metal.

  10. Bifunctional oxygen/air electrodes

    NASA Astrophysics Data System (ADS)

    Jörissen, Ludwig

    A selective review on the materials and construction principles used for bifunctional oxygen/air electrodes is given. The discussion emphasizes the catalytically active materials used for the construction of these electrodes, which are a key component in electrically rechargeable air breathing electrochemical systems. Whereas, in acid electrolytes normally noble metal catalysts must be used, there is a possibility to use less expensive transition metal oxides in alkaline electrolytes. Typical transition metal oxides have the perovskite, pyrochlore and spinel structure.

  11. FUEL CELL ELECTRODE MATERIALS

    DTIC Science & Technology

    FUEL CELL ELECTRODE MATERIALS. RAW MATERIAL SELECTION INFLUENCES POLARIZATION BUT IS NOT A SINGLE CONTROLLING FACTOR. AVAILABLE...DATA INDICATES THAT AN INTERRELATIONSHIP OF POROSITY, AVERAGE PORE VOLUME, AND PERMEABILITY CONTRIBUTES TO ELECTRODE FUEL CELL BEHAVIOR.

  12. Experimental study of cylindrical air electrodes

    NASA Astrophysics Data System (ADS)

    Viitanen, M.; Lamminen, J.; Lampinen, M. J.

    1991-11-01

    The electrodes studied here are cylindrical and prepared to be placed inside the inner surface of a sintered brass tube, which is nickel-plated. Previously we have reported on the preparation of flat air electrodes and also on long run tests carried out with these electrodes. The electrode material was prepared by the so-called wet method to obtain a carbon dough which is easy to handle. The material preparation remains the same, but owing to the different geometrical shape, the preparation of the electrode itself is quite different. We have studied here the long-term performance of these new cylindrical air electrodes and at the same time measured the carbonate content of the electrolyte. We have also analyzed by comparative methods which property of the electrode lowers the performance after a fairly long period.

  13. Improved zinc electrode and rechargeable zinc-air battery

    SciTech Connect

    Ross, P.N. Jr.

    1988-06-21

    The invention comprises an improved rechargeable zinc-air cell/battery having recirculating alkaline electrolyte and a zinc electrode comprising a porous foam support material which carries the active zinc electrode material. 5 figs.

  14. 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.

  15. Electrode materials for rechargeable batteries

    DOEpatents

    Abouimrane, Ali; Amine, Khalil

    2015-04-14

    Selenium or selenium-containing compounds may be used as electroactive materials in electrodes or electrochemical devices. The selenium or selenium-containing compound is mixed with a carbon material.

  16. In Situ-Grown ZnCo2O4 on Single-Walled Carbon Nanotubes as Air Electrode Materials for Rechargeable Lithium–Oxygen Batteries

    SciTech Connect

    Liu, Bin; Xu, Wu; Yan, Pengfei; Bhattacharya, Priyanka; Cao, Ruiguo; Bowden, Mark E.; Engelhard, Mark H.; Wang, Chong M.; Zhang, Jiguang

    2015-10-12

    Although lithium-oxygen (Li-O2) batteries have great potential to be used as one of the next generation energy storage systems due to their ultrahigh theoretical specific energy, there are still many significant barriers before their practical applications. These barriers include electrolyte and electrode instability, poor ORR/OER efficiency and cycling capability, etc. Development of a highly efficient catalyst will not only enhance ORR/OER efficiency, it may also improve the stability of electrolyte because the reduced charge voltage. Here we report the synthesis of nano-sheet-assembled ZnCo2O4 spheres/single walled carbon nanotubes (ZCO/SWCNTs) composites as high performance air electrode materials for Li-O2 batteries. The ZCO catalyzed SWCNTs electrodes delivered high discharge capacities, decreased the onset of oxygen evolution reaction by 0.9 V during charge processes, and led to more stable cycling stability. These results indicate that ZCO/SWCNTs composite can be used as highly efficient air electrode for oxygen reduction and evolution reactions. The highly enhanced catalytic activity by uniformly dispersed ZnCo2O4 catalyst on nanostructured electrodes is expected to inspire

  17. Redox electrode materials for supercapatteries

    NASA Astrophysics Data System (ADS)

    Yu, Linpo; Chen, George Z.

    2016-09-01

    Redox electrode materials, including transition metal oxides and electronically conducting polymers, are capable of faradaic charge transfer reactions, and play important roles in most electrochemical energy storage devices, such as supercapacitor, battery and supercapattery. Batteries are often based on redox materials with low power capability and safety concerns in some cases. Supercapacitors, particularly those based on redox inactive materials, e.g. activated carbon, can offer high power output, but have relatively low energy capacity. Combining the merits of supercapacitor and battery into a hybrid, the supercapattery can possess energy as much as the battery and output a power almost as high as the supercapacitor. Redox electrode materials are essential in the supercapattery design. However, it is hard to utilise these materials easily because of their intrinsic characteristics, such as the low conductivity of metal oxides and the poor mechanical strength of conducting polymers. This article offers a brief introduction of redox electrode materials, the basics of supercapattery and its relationship with pseudocapacitors, and reviews selectively some recent progresses in the relevant research and development.

  18. Electrode materials for rechargeable battery

    DOEpatents

    Johnson, Christopher; Kang, Sun-Ho

    2015-09-08

    A positive electrode is disclosed for a non-aqueous electrolyte lithium rechargeable cell or battery. The electrode comprises a lithium containing material of the formula Na.sub.yLi.sub.xNi.sub.zMn.sub.1-z-z'M.sub.z'O.sub.d, wherein M is a metal cation, x+y>1, 0material preferably has a spinel or spinel-like component in its structure. The value of y preferably is less than about 0.2, and M comprises one or more metal cations selected preferably from one or more monovalent, divalent, trivalent or tetravalent cations, such as Mg.sup.2+, Co.sup.2+, Co.sup.3+, B.sup.3+, Ga.sup.3+, Fe.sup.2+, Fe.sup.3+, Al.sup.3+, and Ti.sup.4+. The electrode material can be synthesized using an ion-exchange reaction with a lithium salt in an organic-based solvent to partially replace sodium ions of a precursor material with lithium ions.

  19. Monodisperse CoFe2O4 nanoparticles supported on Vulcan XC-72: High performance electrode materials for lithium-air and lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Şener, Tansel; Kayhan, Emine; Sevim, Melike; Metin, Önder

    2015-08-01

    Addressed herein is the preparation and the electrode performance of monodisperse CoFe2O4 nanoparticles (NPs) supported on Vulcan XC-72 for the Lithium-air battery (LAB) and Lithium-ion battery (LIB). Monodisperse CoFe2O4 NPs were synthesized by the thermal decomposition of cobalt(II) acetylacetonate and iron(III) acetylacetonate in oleylamine and oleic acid in the presence of 1,2-tetradecanediol and benzyl ether. As-prepared CoFe2O4 NPs with a particle size of 11 nm were then supported on Vulcan XC-72 (Vulcan-CoFe2O4) at different theoretical loadings (20, 40 and 60 wt % CoFe2O4 NPs) by using the simple liquid phase self assembly method. CoFe2O4 NPs dispersed on Vulcan-CoFe2O4 composites were characterized by transmission electron microscopy (TEM), powder X-ray diffraction (PXRD) and atomic absorption spectroscopy (AAS). The AAS analyses indicated that the Vulcan-CoFe2O4 composites with different loadings were included 3.7, 8.1 and 16.4 wt % CoFe2O4 on the metal basis. The electrode performance of Vulcan-CoFe2O4 composites were evaluated as the anode active material for LIB and cathode active material for LABs by performing the galvanostatic charge-discharge tests. The highest discharge capacity for both LAB (7510 mAh g(Vulcan+CoFe2O4)-1; 13380 mAh gCoFe2O4-1 @ 0.1C) and LIB (863 mAh g(Vulcan+CoFe2O4)-1; 9330 mAh gCoFe2O4-1@ 0.1C) was investigated with 16.4 wt % CoFe2O4.

  20. Air electrode composition for solid oxide fuel cell

    DOEpatents

    Kuo, L.; Ruka, R.J.; Singhal, S.C.

    1999-08-03

    An air electrode composition for a solid oxide fuel cell is disclosed. The air electrode material is based on lanthanum manganite having a perovskite-like crystal structure ABO{sub 3}. The A-site of the air electrode composition comprises a mixed lanthanide in combination with rare earth and alkaline earth dopants. The B-site of the composition comprises Mn in combination with dopants such as Mg, Al, Cr and Ni. The mixed lanthanide comprises La, Ce, Pr and, optionally, Nd. The rare earth A-site dopants preferably comprise La, Nd or a combination thereof, while the alkaline earth A-site dopant preferably comprises Ca. The use of a mixed lanthanide substantially reduces raw material costs in comparison with compositions made from high purity lanthanum starting materials. The amount of the A-site and B-site dopants is controlled in order to provide an air electrode composition having a coefficient of thermal expansion which closely matches that of the other components of the solid oxide fuel cell. 3 figs.

  1. Air electrode composition for solid oxide fuel cell

    DOEpatents

    Kuo, Lewis; Ruka, Roswell J.; Singhal, Subhash C.

    1999-01-01

    An air electrode composition for a solid oxide fuel cell is disclosed. The air electrode material is based on lanthanum manganite having a perovskite-like crystal structure ABO.sub.3. The A-site of the air electrode composition comprises a mixed lanthanide in combination with rare earth and alkaline earth dopants. The B-site of the composition comprises Mn in combination with dopants such as Mg, Al, Cr and Ni. The mixed lanthanide comprises La, Ce, Pr and, optionally, Nd. The rare earth A-site dopants preferably comprise La, Nd or a combination thereof, while the alkaline earth A-site dopant preferably comprises Ca. The use of a mixed lanthanide substantially reduces raw material costs in comparison with compositions made from high purity lanthanum starting materials. The amount of the A-site and B-site dopants is controlled in order to provide an air electrode composition having a coefficient of thermal expansion which closely matches that of the other components of the solid oxide fuel cell.

  2. Characterization of gas diffusion electrodes for metal-air batteries

    NASA Astrophysics Data System (ADS)

    Danner, Timo; Eswara, Santhana; Schulz, Volker P.; Latz, Arnulf

    2016-08-01

    Gas diffusion electrodes are commonly used in high energy density metal-air batteries for the supply of oxygen. Hydrophobic binder materials ensure the coexistence of gas and liquid phase in the pore network. The phase distribution has a strong influence on transport processes and electrochemical reactions. In this article we present 2D and 3D Rothman-Keller type multiphase Lattice-Boltzmann models which take into account the heterogeneous wetting behavior of gas diffusion electrodes. The simulations are performed on FIB-SEM 3D reconstructions of an Ag model electrode for predefined saturation of the pore space with the liquid phase. The resulting pressure-saturation characteristics and transport correlations are important input parameters for modeling approaches on the continuum scale and allow for an efficient development of improved gas diffusion electrodes.

  3. LOWER TEMPERATURE ELECTROLYTE AND ELECTRODE MATERIALS

    SciTech Connect

    Keqin Huang

    2003-04-30

    A thorough literature survey on low-temperature electrolyte and electrode materials for SOFC is given in this report. Thermodynamic stability of selected electrolyte and its chemical compatibility with cathode substrate were evaluated. Preliminary electrochemical characterizations were conducted on symmetrical cells consisting of the selected electrolyte and various electrode materials. Feasibility of plasma spraying new electrolyte material thin-film on cathode substrate was explored.

  4. Bifunctional air electrodes containing elemental iron powder charging additive

    DOEpatents

    Liu, Chia-tsun; Demczyk, Brian G.; Gongaware, Paul R.

    1982-01-01

    A bifunctional air electrode for use in electrochemical energy cells is made, comprising a hydrophilic layer and a hydrophobic layer, where the hydrophilic layer essentially comprises a hydrophilic composite which includes: (i) carbon; (ii) elemental iron particles having a particle size of between about 25 microns and about 700 microns diameter; (iii) an oxygen evolution material; (iv) a nonwetting agent; and (v) a catalyst, where at least one current collector is formed into said composite.

  5. Architecture engineering of supercapacitor electrode materials

    NASA Astrophysics Data System (ADS)

    Chen, Kunfeng; Li, Gong; Xue, Dongfeng

    2016-02-01

    The biggest challenge for today’s supercapacitor systems readily possessing high power density is their low energy density. Their electrode materials with controllable structure, specific surface area, electronic conductivity, and oxidation state, have long been highlighted. Architecture engineering of functional electrode materials toward powerful supercapacitor systems is becoming a big fashion in the community. The construction of ion-accessible tunnel structures can microscopically increase the specific capacitance and materials utilization; stiff 3D structures with high specific surface area can macroscopically assure high specific capacitance. Many exciting findings in electrode materials mainly focus on the construction of ice-folded graphene paper, in situ functionalized graphene, in situ crystallizing colloidal ionic particles and polymorphic metal oxides. This feature paper highlights some recent architecture engineering strategies toward high-energy supercapacitor electrode systems, including electric double-layer capacitance (EDLC) and pseudocapacitance.

  6. Advanced Materials for Neural Surface Electrodes

    PubMed Central

    Schendel, Amelia A.; Eliceiri, Kevin W.; Williams, Justin C.

    2015-01-01

    Designing electrodes for neural interfacing applications requires deep consideration of a multitude of materials factors. These factors include, but are not limited to, the stiffness, biocompatibility, biostability, dielectric, and conductivity properties of the materials involved. The combination of materials properties chosen not only determines the ability of the device to perform its intended function, but also the extent to which the body reacts to the presence of the device after implantation. Advances in the field of materials science continue to yield new and improved materials with properties well-suited for neural applications. Although many of these materials have been well-established for non-biological applications, their use in medical devices is still relatively novel. The intention of this review is to outline new material advances for neural electrode arrays, in particular those that interface with the surface of the nervous tissue, as well as to propose future directions for neural surface electrode development. PMID:26392802

  7. Advanced Materials for Neural Surface Electrodes.

    PubMed

    Schendel, Amelia A; Eliceiri, Kevin W; Williams, Justin C

    2014-12-01

    Designing electrodes for neural interfacing applications requires deep consideration of a multitude of materials factors. These factors include, but are not limited to, the stiffness, biocompatibility, biostability, dielectric, and conductivity properties of the materials involved. The combination of materials properties chosen not only determines the ability of the device to perform its intended function, but also the extent to which the body reacts to the presence of the device after implantation. Advances in the field of materials science continue to yield new and improved materials with properties well-suited for neural applications. Although many of these materials have been well-established for non-biological applications, their use in medical devices is still relatively novel. The intention of this review is to outline new material advances for neural electrode arrays, in particular those that interface with the surface of the nervous tissue, as well as to propose future directions for neural surface electrode development.

  8. Electrocatalysts for bifunctional oxygen/air electrodes

    NASA Astrophysics Data System (ADS)

    Nikolova, V.; Iliev, P.; Petrov, K.; Vitanov, T.; Zhecheva, E.; Stoyanova, R.; Valov, I.; Stoychev, D.

    Oxygen reduction and evolution have been studied with respect to the development of bifunctional air/oxygen electrode (BFE). Three groups of catalysts have been prepared: (i) Cu xCo 3- xO 4 by thermal decomposition of mixed nitrate and carbonate precursors; (ii) thin films of Co-Ni-Te-O and Co-Te-O were deposited by vacuum co-evaporation of Co, Ni and TeO 2 and (iii) Co xO v/ZrO 2 films were obtained by electrochemical deposition. The electrochemical behavior of the chemically synthesized catalysts was studied on classical bilayered gas diffusion electrodes (GDEs), where the catalyst is in form of powder. The GDE catalyzed with vacuum deposited catalysts was prepared by direct deposition of the catalyst on gas-supplying layer, thus creating a ready-to-use gas diffusion electrode. Catalysts prepared electrochemically were first deposited on Ni foam and than pressed onto the gas-supplying layer. Different catalysts deposited on classical and originally designed GDEs were compared by their electrochemical performances. Cu 0.3Co 2.7O 4 deposited on a classical bilayered GDE with loading of 50 mg cm -2 exhibits stable current-voltage characteristics after 200 charge-discharge cycles in a real metal hydride-air battery. The electrochemically and vacuum deposited Co xO v/ZrO 2, Co-Ni-Te-O and Co-Te-O films exhibit much higher mass activity compared to Cu 0.2Co 2.8O 4 for both oxygen reduction and evolution reactions. The difference is that the loading of electrochemically and vacuum deposited films is 0.06 mg cm -2 only, which is a substantial advantage from a practical viewpoint.

  9. Oxide modified air electrode surface for high temperature electrochemical cells

    DOEpatents

    Singh, Prabhakar; Ruka, Roswell J.

    1992-01-01

    An electrochemical cell is made having a porous cermet electrode (16) and a porous lanthanum manganite electrode (14), with solid oxide electrolyte (15) between them, where the lanthanum manganite surface next to the electrolyte contains a thin discontinuous layer of high surface area cerium oxide and/or praseodymium oxide, preferably as discrete particles (30) in contact with the air electrode and electrolyte.

  10. Bi-functional air electrodes for metal-air batteries. Final report, September 15, 1993--December 14, 1994

    SciTech Connect

    Swette, L.L.; Manoukian, M.; LaConti, A.B.

    1995-12-01

    The program was directed to the need for development of bifunctional air electrodes for Zn-Air batteries for the consumer market. The Zn-Air system, widely used as a primary cell for hearing-aid batteries and as a remote-site power source in industrial applications, has the advantage of high energy density, since it consumes oxygen from the ambient air utilizing a thin, efficient fuel-cell-type gas-diffusion electrode, and is comparatively low in cost. The disadvantages of the current technology are a relatively low rate capability, and the lack of simple reversibility. {open_quotes}Secondary{close_quotes} Zn-Air cells require a third electrode for oxygen evolution or mechanical replacement of the Zinc anodes; thus the development of a bifunctional air electrode (i.e., an electrode that can alternately consume and evolve oxygen) would be a significant advance in Zn-Air cell technology. Evaluations of two carbon-free non-noble metal perovskite-type catalyst systems, La{sub 1-x}CA{sub x}CoO{sub 3} as bifunctional catalysts for potential application in Zn-air batteries were carried out. The technical objectives were to develop higher-surface-area materials and to fabricate reversible electrodes by modifying the hydrophobic/hydrophilic balance of the catalyst-binder structures.

  11. LOWER TEMPERATURE ELECTROLYTE AND ELECTRODE MATERIALS

    SciTech Connect

    Keqin Huang

    2001-04-30

    A thorough literature survey on low-temperature electrolyte and electrode materials for solid oxide fuel cells (SOFC) is presented. Preliminary results of co-sintering LaGaO{sub 3} (LSGM) film on the cathode substrate were also reported. The chemical stability of LSGM in various SOFC environments was thermodynamically assessed and verified by the molten-salt technique.

  12. Gallium Nitride Crystals: Novel Supercapacitor Electrode Materials.

    PubMed

    Wang, Shouzhi; Zhang, Lei; Sun, Changlong; Shao, Yongliang; Wu, Yongzhong; Lv, Jiaxin; Hao, Xiaopeng

    2016-05-01

    A type of single-crystal gallium nitride mesoporous membrane is fabricated and its supercapacitor properties are demonstrated for the first time. The supercapacitors exhibit high-rate capability, stable cycling life at high rates, and ultrahigh power density. This study may expand the range of crystals as high-performance electrode materials in the field of energy storage.

  13. Reversibly immobilized biological materials in monolayer films on electrodes

    SciTech Connect

    Weaver, P.F.; Frank, A.J.

    1991-04-08

    A method is provided for reversibly binding charged biological particles in a fluid medium to an electrode surface. The method comprises treating (e.g., derivatizing) the electrode surface with an electrochemically active material; connecting the electrode to an electrical potential; and exposing the fluid medium to the electrode surface in a manner such that the charged particles become adsorbed on the electrode surface.

  14. Synthesis, characterization and application of electrode materials

    SciTech Connect

    He, Lin

    1995-07-07

    It has been known that significant advances in electrochemistry really depend on improvements in the sensitivity, selectivity, convenience, and/or economy of working electrodes, especially through the development of new working electrode materials. The advancement of solid state chemistry and materials science makes it possible to provide the materials which may be required as satisfactory electrode materials. The combination of solid state techniques with electrochemistry expands the applications of solid state materials and leads to the improvement of electrocatalysis. The study of Ru-Ti4O7 and Pt-Ti4O7 microelectrode arrays as introduced in paper 1 and paper 4, respectively, focuses on their synthesis and characterization. The synthesis is described by high temperature techniques for Ru or Pt microelectrode arrays within a conductive Ti4O7ceramic matrix. The characterization is based on the data obtained by x-ray diffractometry, scanning electron microscopy, voltammetry and amperometry. These microelectrode arrays show significant enhancement in current densities in comparison to solid Ru and Pt electrodes. Electrocatalysis at pyrochlore oxide Bi2Ru2O7.3 and Bi2Ir2O7 electrodes are described in paper 2 and paper 3, respectively. Details are reported for the synthesis and characterization of composite Bi2Ru2O7.3 electrodes. Voltammetric data are examined for evidence that oxidation can occur with transfer of oxygen to the oxidation products in the potential region corresponding to anodic discharge of H2O with simultaneous evolution of O2. Paper 3 includes electrocatalytic activities of composite Bi2Ir2O7 disk electrodes for the oxidation of I- and the reduction of IO3-.

  15. Lanthanum manganite-based air electrode for solid oxide fuel cells

    DOEpatents

    Ruka, R.J.; Kuo, L.; Li, B.

    1999-06-29

    An air electrode material for a solid oxide fuel cell is disclosed. The electrode material is based on lanthanum manganite having a perovskite-like crystal structure ABO[sub 3]. The A-site of the air electrode material preferably comprises La, Ca, Ce and at least one lanthanide selected from Sm, Gd, Dy, Er, Y and Nd. The B-site of the electrode material comprises Mn with substantially no dopants. The ratio of A:B is preferably slightly above 1. A preferred air electrode composition is of the formula La[sub w]Ca[sub x]Ln[sub y]Ce[sub z]MnO[sub 3], wherein Ln comprises at least one lanthanide selected from Sm, Gd, Dy, Er, Y and Nd, w is from about 0.55 to about 0.56, x is from about 0.255 to about 0.265, y is from about 0.175 to about 0.185, and z is from about 0.005 to about 0.02. The air electrode material possesses advantageous chemical and electrical properties as well as favorable thermal expansion and thermal cycle shrinkage characteristics. 10 figs.

  16. Lanthanum manganite-based air electrode for solid oxide fuel cells

    DOEpatents

    Ruka, Roswell J.; Kuo, Lewis; Li, Baozhen

    1999-01-01

    An air electrode material for a solid oxide fuel cell is disclosed. The electrode material is based on lanthanum manganite having a perovskite-like crystal structure ABO.sub.3. The A-site of the air electrode material preferably comprises La, Ca, Ce and at least one lanthanide selected from Sm, Gd, Dy, Er, Y and Nd. The B-site of the electrode material comprises Mn with substantially no dopants. The ratio of A:B is preferably slightly above 1. A preferred air electrode composition is of the formula La.sub.w Ca.sub.x Ln.sub.y Ce.sub.z MnO.sub.3, wherein Ln comprises at least one lanthanide selected from Sm, Gd, Dy, Er, Y and Nd, w is from about 0.55 to about 0.56, x is from about 0.255 to about 0.265, y is from about 0.175 to about 0.185, and z is from about 0.005 to about 0.02. The air electrode material possesses advantageous chemical and electrical properties as well as favorable thermal expansion and thermal cycle shrinkage characteristics.

  17. Electrostatic atomization: Effect of electrode materials on electrostatic atomizer performance

    NASA Astrophysics Data System (ADS)

    Sankaran, Abhilash; Staszel, Christopher; Kashir, Babak; Perri, Anthony; Mashayek, Farzad; Yarin, Alexander

    2016-11-01

    Electrostatic atomization was studied experimentally with a pointed electrode in a converging nozzle. Experiments were carried out on poorly conductive canola oil where it was observed that electrode material may affect charge transfer. This points at the possible faradaic reactions that can occur at the surfaces of the electrodes. The supply voltage is applied to the sharp electrode and the grounded nozzle body constitutes the counter-electrode. The charge transfer is controlled by the electrochemical reactions on both the electrodes. The electrical performance study of the atomizer issuing a charged oil jet was conducted using three different nozzle body materials - brass, copper and stainless steel. Also, two sharp electrode materials - brass and stainless steel - were tested. The experimental results revealed that both the nozzle body material, as well as the sharp electrode material affected the spray and leak currents. Moreover, the effect of the sharp electrode material is quite significant. This research is supported by NSF Grant 1505276.

  18. Vanadium based materials as electrode materials for high performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Yan, Yan; Li, Bing; Guo, Wei; Pang, Huan; Xue, Huaiguo

    2016-10-01

    As a kind of supercapacitors, pseudocapacitors have attracted wide attention in recent years. The capacitance of the electrochemical capacitors based on pseudocapacitance arises mainly from redox reactions between electrolytes and active materials. These materials usually have several oxidation states for oxidation and reduction. Many research teams have focused on the development of an alternative material for electrochemical capacitors. Many transition metal oxides have been shown to be suitable as electrode materials of electrochemical capacitors. Among them, vanadium based materials are being developed for this purpose. Vanadium based materials are known as one of the best active materials for high power/energy density electrochemical capacitors due to its outstanding specific capacitance and long cycle life, high conductivity and good electrochemical reversibility. There are different kinds of synthetic methods such as sol-gel hydrothermal/solvothermal method, template method, electrospinning method, atomic layer deposition, and electrodeposition method that have been successfully applied to prepare vanadium based electrode materials. In our review, we give an overall summary and evaluation of the recent progress in the research of vanadium based materials for electrochemical capacitors that include synthesis methods, the electrochemical performances of the electrode materials and the devices.

  19. Performance and cycle life of carbon- and conductive-based air electrodes for rechargeable Zn-air battery applications

    NASA Astrophysics Data System (ADS)

    Chellapandi Velraj, Samgopiraj

    The development of high-performance, cyclically stable bifunctional air electrodes are critical to the commercial deployment of rechargeable Zn-air batteries. The carbon material predominantly used as support material in the air electrodes due to its higher surface area and good electrical conductivity suffers from corrosion at high oxygen evolution overpotentials. This study addresses the carbon corrosion issues and suggests alternate materials to replace the carbon as support in the air electrode. In this study, Sm0.5Sr0.5CoO3-delta with good electrochemical performance and cyclic lifetime was identified as an alternative catalyst material to the commonly used La0.4Ca 0.6CoO3 catalyst for the carbon-based bifunctional electrodes. Also, a comprehensive study on the effects of catalyst morphology, testing conditions on the cycle life as well as the relevant degradation mechanism for the carbon-based electrode was conducted in this dissertation. The cyclic life of the carbon-based electrodes was strongly dependent on the carbon support material, while the degradation mechanisms were entirely controlled by the catalyst particle size/morphology. Some testing conditions like resting time and electrolyte concentration did not change the cyclic life or degradation mechanism of the carbon-based electrode. The current density used for cyclic testing was found to dictate the degradation mechanism leading to the electrode failure. An alternate way to circumvent the carbon corrosion is to replace the carbon support with a suitable electrically-conductive ceramic material. In this dissertation, LaNi0.9Mn0.1O3, LaNi 0.8Co0.2O3, and NiCo2O4 were synthesized and evaluated as prospective support materials due to their good electrical conductivity and their ability to act as the catalyst needed for the bifunctional electrode. The carbon-free electrodes had remarkably higher catalytic activity for oxygen evolution reaction (OER) when compared to the carbon-based electrode. However

  20. Zinc electrode and rechargeable zinc-air battery

    SciTech Connect

    Ross, P.N. Jr.

    1989-06-27

    This patent describes an improved zinc electrode for a rechargeable zinc-air battery comprising an outer frame and a porous foam electrode support within the frame which is treated prior to the deposition of zinc thereon to inhibit the formation of zinc dendrites on the external surface thereof. The outer frame is provided with passageways for circulating an alkaline electrolyte through the treated zinc-coated porous foam. A novel rechargeable zinc-air battery system is also disclosed.

  1. Screening of redox couples and electrode materials

    NASA Technical Reports Server (NTRS)

    Giner, J.; Swette, L.; Cahill, K.

    1976-01-01

    Electrochemical parameters of selected redox couples that might be potentially promising for application in bulk energy storage systems were investigated. This was carried out in two phases: a broad investigation of the basic characteristics and behavior of various redox couples, followed by a more limited investigation of their electrochemical performance in a redox flow reactor configuration. In the first phase of the program, eight redox couples were evaluated under a variety of conditions in terms of their exchange current densities as measured by the rotating disk electrode procedure. The second phase of the program involved the testing of four couples in a redox reactor under flow conditions with a varity of electrode materials and structures.

  2. Lithium Manganese Silicate Positive Electrode Material

    NASA Astrophysics Data System (ADS)

    Yang, Qiong

    As the fast development of the electronic portable devices and drastic fading of fossil energy sources. The need for portable secondary energy sources is increasingly urgent. As a result, lithium ion batteries are being investigated intensely to meet the performance requirements. Among various electrode materials, the most expensive and capacity limiting component is the positive materials. Based on this, researches have been mostly focused on the development of novel cathode materials with high capacity and energy density and the lithium transition metal orthosilicates have been identified as possible high performance cathodes. Here in, we report the synthesis of a kind of lithium transition metal orthosilicates electrode lithium manganese silicate. Lithium manganese silicate has the advantage of high theoretical capacity, low cost raw material and safety. In this thesis, lithium manganese silicate are prepared using different silicon sources. The structure of silicon sources preferred are examined. Nonionic block copolymers surfactant, P123, is tried as carbon source and mophology directing agent. Lithium manganese silicate's performances are improved by adding P123.

  3. Zinc electrode and rechargeable zinc-air battery

    SciTech Connect

    Ross, Jr., Philip N.

    1989-01-01

    An improved zinc electrode is disclosed for a rechargeable zinc-air battery comprising an outer frame and a porous foam electrode support within the frame which is treated prior to the deposition of zinc thereon to inhibit the formation of zinc dendrites on the external surface thereof. The outer frame is provided with passageways for circulating an alkaline electrolyte through the treated zinc-coated porous foam. A novel rechargeable zinc-air battery system is also disclosed which utilizes the improved zinc electrode and further includes an alkaline electrolyte within said battery circulating through the passageways in the zinc electrode and an external electrolyte circulation means which has an electrolyte reservoir external to the battery case including filter means to filter solids out of the electrolyte as it circulates to the external reservoir and pump means for recirculating electrolyte from the external reservoir to the zinc electrode.

  4. Improving Electrode Durability of PEF Chamber by selecting suitable material

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion resistance of four materials - titanium, platinized titanium, stainless steel, and boron carbide - as electrodes in a Pulsed Electric Field (PEF) system was studied to reduce electrode material migration into the food by electrode corrosion. The PEF process conditions were 28 kV/cm field s...

  5. Stability in alkaline aqueous electrolyte of air electrode protected with fluorinated interpenetrating polymer network membrane

    NASA Astrophysics Data System (ADS)

    Bertolotti, Bruno; Messaoudi, Houssam; Chikh, Linda; Vancaeyzeele, Cédric; Alfonsi, Séverine; Fichet, Odile

    2015-01-01

    We developed original anion exchange membranes to protect air electrodes operating in aqueous lithium-air battery configuration, i.e. supplied with atmospheric air and in concentrated aqueous lithium hydroxide. These protective membranes have an interpenetrating polymer network (IPN) architecture combining a hydrogenated cationic polyelectrolyte network based on poly(epichlorohydrin) (PECH) and a fluorinated neutral network based on perfluoropolyether (Fluorolink® MD700). Two phases, each one rich in one of the polymer, are co-continuous in the materials. This morphology allows combining their properties according to the weight proportions of each polymer. Thus, PECH/Fluorolink IPNs show ionic conductivity varying from 1 to 2 mS cm-1, water uptake from 30 to 90 wt.% and anionic transport number from 0.65 to 0.80 when the PECH proportion varies from 40 to 90 wt.%. These membranes have been systematically assembled on air electrodes. Air electrode protected with PECH/Fluorolink 70/30 IPN shows outstanding stability higher than 1000 h, i.e. a 20-fold increase in the lifetime of the non-modified electrode. This efficient membrane/air electrode assembly is promising for development of alkaline electrolyte based storage or production energy systems, such as metal air batteries or alkaline fuel cells.

  6. Nanostructured Electrode Materials for Electrochemical Capacitor Applications

    PubMed Central

    Choi, Hojin; Yoon, Hyeonseok

    2015-01-01

    The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013). Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead. PMID:28347044

  7. Metal | polypyrrole battery with the air regenerated positive electrode

    NASA Astrophysics Data System (ADS)

    Grgur, Branimir N.

    2014-12-01

    Recharge characteristics of the battery based on the electrochemically synthesized polypyrrole cathode and aluminum, zinc, or magnesium anode in 2 M NH4Cl are investigated. It is shown that polypyrrole electrode can be regenerated by the reoxidation with the dissolved oxygen from the air. Using the polypyrrole synthesized on high surface graphite-felt electrode under modest discharge conditions, stable discharge voltage of 1.1 V is obtained. Such behavior is explained by the complex interaction of polypyrrole and hydrogen peroxide produced by the oxygen reduction reaction. The electrochemical characteristics are compared with the zinc-manganese dioxide and zinc-air systems.

  8. Extrusion of electrode material by liquid injection into extruder barrel

    DOEpatents

    Keller, David Gerard; Giovannoni, Richard Thomas; MacFadden, Kenneth Orville

    1998-01-01

    An electrode sheet product is formed using an extruder having a feed throat and a downstream section by separately mixing an active electrode material and a solid polymer electrolyte composition that contains lithium salt. The active electrode material is fed into the feed throat of the extruder, while a portion of at least one fluid component of the solid polymer electrolyte composition is introduced to the downstream section. The active electrode material and the solid polymer electrolyte composition are compounded in a downstream end of the extruder. The extruded sheets, adhered to current collectors, can be formed into battery cells.

  9. Extrusion of electrode material by liquid injection into extruder barrel

    DOEpatents

    Keller, D.G.; Giovannoni, R.T.; MacFadden, K.O.

    1998-03-10

    An electrode sheet product is formed using an extruder having a feed throat and a downstream section by separately mixing an active electrode material and a solid polymer electrolyte composition that contains lithium salt. The active electrode material is fed into the feed throat of the extruder, while a portion of at least one fluid component of the solid polymer electrolyte composition is introduced to the downstream section. The active electrode material and the solid polymer electrolyte composition are compounded in a downstream end of the extruder. The extruded sheets, adhered to current collectors, can be formed into battery cells. 1 fig.

  10. Reversible air electrodes integrated with an anion-exchange membrane for secondary air batteries

    NASA Astrophysics Data System (ADS)

    Fujiwara, Naoko; Yao, Masaru; Siroma, Zyun; Senoh, Hiroshi; Ioroi, Tsutomu; Yasuda, Kazuaki

    Reversible air electrodes integrated with a polymer electrolyte membrane have been proposed for use in rechargeable metal-air batteries or unitized regenerative fuel cells to reduce the impact of atmospheric carbon dioxide. Reversible air electrodes were prepared with an anion-exchange membrane (AEM) as a polymer electrolyte membrane and platinum-based catalysts. The AEM at the interface between the alkaline electrolyte and the air electrode layer plays major roles in AEM-type air electrodes as follows: it blocks (a) the permeation of cations in the alkaline electrolyte into the air electrode layer to prevent carbonate precipitation, (b) penetration of the alkaline solution itself, and (c) neutralization of the alkaline electrolyte by carbon dioxide, all of which prevent performance degradation of oxygen reactions. Catalysts for decreasing the overvoltage of oxygen reactions were also investigated with the AEM-type air electrode, and the overall efficiency was improved due to a remarkable decrease in the potential for the oxygen evolution reaction with Pt-Ir catalysts.

  11. Aqueous processing of composite lithium ion electrode material

    DOEpatents

    Li, Jianlin; Armstrong, Beth L; Daniel, Claus; Wood, III, David L

    2015-02-17

    A method of making a battery electrode includes the steps of dispersing an active electrode material and a conductive additive in water with at least one dispersant to create a mixed dispersion; treating a surface of a current collector to raise the surface energy of the surface to at least the surface tension of the mixed dispersion; depositing the dispersed active electrode material and conductive additive on a current collector; and heating the coated surface to remove water from the coating.

  12. Reversibly immobilized biological materials in monolayer films on electrodes

    DOEpatents

    Weaver, Paul F.; Frank, Arthur J.

    1993-01-01

    Methods and techniques are described for reversibly binding charged biological particles in a fluid medium to an electrode surface. The methods are useful in a variety of applications. The biological materials may include microbes, proteins, and viruses. The electrode surface may consist of reversibly electroactive materials such as polyvinylferrocene, silicon-linked ferrocene or quinone.

  13. Reversibly immobilized biological materials in monolayer films on electrodes

    DOEpatents

    Weaver, P.F.; Frank, A.J.

    1993-05-04

    Methods and techniques are described for reversibly binding charged biological particles in a fluid medium to an electrode surface. The methods are useful in a variety of applications. The biological materials may include microbes, proteins, and viruses. The electrode surface may consist of reversibly electroactive materials such as polyvinylferrocene, silicon-linked ferrocene or quinone.

  14. Materials analyses and electrochemical impedance of implantable metal electrodes.

    PubMed

    Howlader, Matiar M R; Ul Alam, Arif; Sharma, Rahul P; Deen, M Jamal

    2015-04-21

    Implantable electrodes with high flexibility, high mechanical fixation and low electrochemical impedance are desirable for neuromuscular activation because they provide safe, effective and stable stimulation. In this paper, we report on detailed materials and electrical analyses of three metal implantable electrodes - gold (Au), platinum (Pt) and titanium (Ti) - using X-ray photoelectron spectroscopy (XPS), scanning acoustic microscopy, drop shape analysis and electrochemical impedance spectroscopy. We investigated the cause of changes in electrochemical impedance of long-term immersed Au, Pt and Ti electrodes on liquid crystal polymers (LCPs) in phosphate buffered saline (PBS). We analyzed the surface wettability, surface and interface defects and the elemental depth profile of the electrode-adhesion layers on the LCP. The impedance of the electrodes decreased at lower frequencies, but increased at higher frequencies compared with that of the short-term immersion. The increase of impedances was influenced by the oxidation of the electrode/adhesion-layers that affected the double layer capacitance behavior of the electrode/PBS. The oxidation of the adhesion layer for all the electrodes was confirmed by XPS. Alkali ions (sodium) were adsorbed on the Au and Pt surfaces, but diffused into the Ti electrode and LCPs. The Pt electrode showed a higher sensitivity to surface and interface defects than that of Ti and Au electrodes. These findings may be useful when designing electrodes for long-term implantable devices.

  15. CNT Sheet Air Electrode for the Development of Ultra-High Cell Capacity in Lithium-Air Batteries

    PubMed Central

    Nomura, Akihiro; Ito, Kimihiko; Kubo, Yoshimi

    2017-01-01

    Lithium-air batteries (LABs) are expected to provide a cell with a much higher capacity than ever attained before, but their prototype cells present a limited areal cell capacity of no more than 10 mAh cm−2, mainly due to the limitation of their air electrodes. Here, we demonstrate the use of flexible carbon nanotube (CNT) sheets as a promising air electrode for developing ultra-high capacity in LAB cells, achieving areal cell capacities of up to 30 mAh cm−2, which is approximately 15 times higher than the capacity of cells with lithium-ion battery (LiB) technology (~2 mAh cm−2). During discharge, the CNT sheet electrode experienced enormous swelling to a thickness of a few millimeters because of the discharge product deposition of lithium peroxide (Li2O2), but the sheet was fully recovered after being fully charged. This behavior results from the CNT sheet characteristics of the flexible and fibrous conductive network and suggests that the CNT sheet is an effective air electrode material for developing a commercially available LAB cell with an ultra-high cell capacity. PMID:28378746

  16. Modified lithium vanadium oxide electrode materials products and methods

    DOEpatents

    Thackeray, Michael M.; Kahaian, Arthur J.; Visser, Donald R.; Dees, Dennis W.; Benedek, Roy

    1999-12-21

    A method of improving certain vanadium oxide formulations is presented. The method concerns fluorine doping formulations having a nominal formula of LiV.sub.3 O.sub.8. Preferred average formulations are provided wherein the average oxidation state of the vanadium is at least 4.6. Herein preferred fluorine doped vanadium oxide materials, electrodes using such materials, and batteries including at least one electrode therein comprising such materials are provided.

  17. A new electrode-active material for polymer batteries: Polyvinylferrocene

    SciTech Connect

    Iwakura, C.; Kawai, T.; Nojima, M.; Yoneyama, H.

    1987-04-01

    The electrochemical characteristics of polyvinylferrocene (PVF) was investigated for use as an electrode-active material rechargeable batteries. Charge-discharge curves of the PVF electrodes showed excellent potential flatness and very high coulombic efficiencies in both nonaqueous and aqueous solutions. The dispersion of graphite powder in PVF was very useful for increasing the discharge rate and PVF utilization. The self-discharge rates were found to be as low as 1% in the first day. It is concluded that PVF is a promising material as an electrode-active material in rechargeable batteries.

  18. Method of preparation of carbon materials for use as electrodes in rechargeable batteries

    DOEpatents

    Doddapaneni, Narayan; Wang, James C. F.; Crocker, Robert W.; Ingersoll, David; Firsich, David W.

    1999-01-01

    A method of producing carbon materials for use as electrodes in rechargeable batteries. Electrodes prepared from these carbon materials exhibit intercalation efficiencies of .apprxeq.80% for lithium, low irreversible loss of lithium, long cycle life, are capable of sustaining a high rates of discharge and are cheap and easy to manufacture. The method comprises a novel two-step stabilization process in which polymeric precursor materials are stabilized by first heating in an inert atmosphere and subsequently heating in air. During the stabilization process, the polymeric precursor material can be agitated to reduce particle fusion and promote mass transfer of oxygen and water vapor. The stabilized, polymeric precursor materials can then be converted to a synthetic carbon, suitable for fabricating electrodes for use in rechargeable batteries, by heating to a high temperature in a flowing inert atmosphere.

  19. Method of preparation of carbon materials for use as electrodes in rechargeable batteries

    DOEpatents

    Doddapaneni, N.; Wang, J.C.F.; Crocker, R.W.; Ingersoll, D.; Firsich, D.W.

    1999-03-16

    A method is described for producing carbon materials for use as electrodes in rechargeable batteries. Electrodes prepared from these carbon materials exhibit intercalation efficiencies of {approx_equal} 80% for lithium, low irreversible loss of lithium, long cycle life, are capable of sustaining a high rates of discharge and are cheap and easy to manufacture. The method comprises a novel two-step stabilization process in which polymeric precursor materials are stabilized by first heating in an inert atmosphere and subsequently heating in air. During the stabilization process, the polymeric precursor material can be agitated to reduce particle fusion and promote mass transfer of oxygen and water vapor. The stabilized, polymeric precursor materials can then be converted to a synthetic carbon, suitable for fabricating electrodes for use in rechargeable batteries, by heating to a high temperature in a flowing inert atmosphere. 4 figs.

  20. Advances in materials and current collecting networks for AMTEC electrodes

    NASA Technical Reports Server (NTRS)

    Ryan, M. A.; Jeffries-Nakamura, B.; Williams, R. M.; Underwood, M. L.; O'Connor, D.; Kikkert, S.

    1992-01-01

    Electrode materials for the Alkali Metal Thermal to Electric Converter (AMTEC) play a significant role in the efficiency of the device. RhW and PtW alloys have been studied to determine the best performing material. While RhW electrodes typically have power densities somewhat lower than PtW electrodes, PtW performance is strongly influenced by the Pt/W ratio. The best performing Pt/W ratio is about 3.4. RhW electrodes sinter more slowly than PtW and are predicted to have operating lifetimes up to 40 years; PtW electrodes are predicted to have lifetimes up to 7 years. Interaction with the current collection network can significantly decrease lifetime by inducing metal migration and segregation and by accelerating the sintering rate.

  1. Fuel cell electrode interconnect contact material encapsulation and method

    DOEpatents

    Derose, Anthony J.; Haltiner, Jr., Karl J.; Gudyka, Russell A.; Bonadies, Joseph V.; Silvis, Thomas W.

    2016-05-31

    A fuel cell stack includes a plurality of fuel cell cassettes each including a fuel cell with an anode and a cathode. Each fuel cell cassette also includes an electrode interconnect adjacent to the anode or the cathode for providing electrical communication between an adjacent fuel cell cassette and the anode or the cathode. The interconnect includes a plurality of electrode interconnect protrusions defining a flow passage along the anode or the cathode for communicating oxidant or fuel to the anode or the cathode. An electrically conductive material is disposed between at least one of the electrode interconnect protrusions and the anode or the cathode in order to provide a stable electrical contact between the electrode interconnect and the anode or cathode. An encapsulating arrangement segregates the electrically conductive material from the flow passage thereby, preventing volatilization of the electrically conductive material in use of the fuel cell stack.

  2. Towards uniformly dispersed battery electrode composite materials: Characteristics and performance

    SciTech Connect

    Yo Han Kwon; Takeuchi, Esther S.; Huie, Matthew M.; Choi, Dalsu; Chang, Mincheol; Marschilok, Amy C.; Takeuchi, Kenneth J.; Reichmanis, Elsa

    2016-01-14

    Battery electrodes are complex mesoscale systems comprised of electroactive components, conductive additives, and binders. In this report, methods for processing electrodes with dispersion of the components are described. To investigate the degree of material dispersion, a spin-coating technique was adopted to provide a thin, uniform layer that enabled observation of the morphology. Distinct differences in the distribution profile of the electrode components arising from individual materials physical affinities were readily identified. Hansen solubility parameter (HSP) analysis revealed pertinent surface interactions associated with materials dispersivity. Further studies demonstrated that HSPs can provide an effective strategy to identify surface modification approaches for improved dispersions of battery electrode materials. Specifically, introduction of surfactantlike functionality such as oleic acid (OA) capping and P3HT-conjugated polymer wrapping on the surface of nanomaterials significantly enhanced material dispersity over the composite electrode. The approach to the surface treatment on the basis of HSP study can facilitate design of composite electrodes with uniformly dispersed morphology and may contribute to enhancing their electrical and electrochemical behaviors. The conductivity of the composites and their electrochemical performance was also characterized. In conclusion, the study illustrates the importance of considering electronic conductivity, electron transfer, and ion transport in the design of environments incorporating active nanomaterials.

  3. Towards uniformly dispersed battery electrode composite materials: Characteristics and performance

    DOE PAGES

    Yo Han Kwon; Takeuchi, Esther S.; Huie, Matthew M.; ...

    2016-01-14

    Battery electrodes are complex mesoscale systems comprised of electroactive components, conductive additives, and binders. In this report, methods for processing electrodes with dispersion of the components are described. To investigate the degree of material dispersion, a spin-coating technique was adopted to provide a thin, uniform layer that enabled observation of the morphology. Distinct differences in the distribution profile of the electrode components arising from individual materials physical affinities were readily identified. Hansen solubility parameter (HSP) analysis revealed pertinent surface interactions associated with materials dispersivity. Further studies demonstrated that HSPs can provide an effective strategy to identify surface modification approaches formore » improved dispersions of battery electrode materials. Specifically, introduction of surfactantlike functionality such as oleic acid (OA) capping and P3HT-conjugated polymer wrapping on the surface of nanomaterials significantly enhanced material dispersity over the composite electrode. The approach to the surface treatment on the basis of HSP study can facilitate design of composite electrodes with uniformly dispersed morphology and may contribute to enhancing their electrical and electrochemical behaviors. The conductivity of the composites and their electrochemical performance was also characterized. In conclusion, the study illustrates the importance of considering electronic conductivity, electron transfer, and ion transport in the design of environments incorporating active nanomaterials.« less

  4. Toward Uniformly Dispersed Battery Electrode Composite Materials: Characteristics and Performance.

    PubMed

    Kwon, Yo Han; Huie, Matthew M; Choi, Dalsu; Chang, Mincheol; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S; Reichmanis, Elsa

    2016-02-10

    Battery electrodes are complex mesoscale systems comprised of electroactive components, conductive additives, and binders. In this report, methods for processing electrodes with dispersion of the components are described. To investigate the degree of material dispersion, a spin-coating technique was adopted to provide a thin, uniform layer that enabled observation of the morphology. Distinct differences in the distribution profile of the electrode components arising from individual materials physical affinities were readily identified. Hansen solubility parameter (HSP) analysis revealed pertinent surface interactions associated with materials dispersivity. Further studies demonstrated that HSPs can provide an effective strategy to identify surface modification approaches for improved dispersions of battery electrode materials. Specifically, introduction of surfactantlike functionality such as oleic acid (OA) capping and P3HT-conjugated polymer wrapping on the surface of nanomaterials significantly enhanced material dispersity over the composite electrode. The approach to the surface treatment on the basis of HSP study can facilitate design of composite electrodes with uniformly dispersed morphology and may contribute to enhancing their electrical and electrochemical behaviors. The conductivity of the composites and their electrochemical performance was also characterized. The study illustrates the importance of considering electronic conductivity, electron transfer, and ion transport in the design of environments incorporating active nanomaterials.

  5. Electrode materials for biphenyl-based rectification devices.

    PubMed

    Parashar, Sweta; Srivastava, Pankaj; Pattanaik, Manisha

    2013-10-01

    An ab initio approach was utilized to explore the electronic transport properties of 4'-thiolate-biphenyl-4-dithiocarboxylate (TBDT) sandwiched between two electrodes made of various materials X (X = Cu, Ag, and Au). Analysis of current-voltage (I-V) characteristics, rectification performance, transmission functions, and the projected density of states (PDOS) under various external voltage biases showed that the transport properties of these constructed systems are markedly impacted by the choice of electrode materials. Further, Cu electrodes yield the best rectifying behavior, followed by Ag and then Au electrodes. Interestingly, the rectification effects can be tuned by changing the torsion angle between the two phenyl rings, as well as by stretching the contact distances between the end group and the electrodes. For Cu, the maximum rectifying ratio increases by 37 % as the contact distance changes from 1.7 Å to 1.9 Å. This is due to an increase in coupling strength asymmetry between the molecule and the electrodes. Our findings are compared with the results reported for other systems. The present calculations are helpful not only for predicting the optimal electrode material for practical applications but also for achieving better control over rectifying performance in molecular devices.

  6. Effect of oxidation of carbon material on suspension electrodes for flow electrode capacitive deionization.

    PubMed

    Hatzell, Kelsey B; Hatzell, Marta C; Cook, Kevin M; Boota, Muhammad; Housel, Gabrielle M; McBride, Alexander; Kumbur, E Caglan; Gogotsi, Yury

    2015-03-03

    Flow electrode deionization (FCDI) is an emerging area for continuous and scalable deionization, but the electrochemical and flow properties of the flow electrode need to be improved to minimize energy consumption. Chemical oxidation of granular activated carbon (AC) was examined here to study the role of surface heteroatoms on rheology and electrochemical performance of a flow electrode (carbon slurry) for deionization processes. Moreover, it was demonstrated that higher mass densities could be used without increasing energy for pumping when using oxidized active material. High mass-loaded flow electrodes (28% carbon content) based on oxidized AC displayed similar viscosities (∼21 Pa s) to lower mass-loaded flow electrodes (20% carbon content) based on nonoxidized AC. The 40% increased mass loading (from 20% to 28%) resulted in a 25% increase in flow electrode gravimetric capacitance (from 65 to 83 F g(-1)) without sacrificing flowability (viscosity). The electrical energy required to remove ∼18% of the ions (desalt) from of the feed solution was observed to be significantly dependent on the mass loading and decreased (∼60%) from 92 ± 7 to 28 ± 2.7 J with increased mass densities from 5 to 23 wt %. It is shown that the surface chemistry of the active material in a flow electrode effects the electrical and pumping energy requirements of a FCDI system.

  7. Effect of oxidation of carbon material on suspension electrodes for flow electrode capacitive deionization

    SciTech Connect

    Hatzell, Kelsey B.; Hatzell, Marta C.; Cook, Kevin M.; Boota, Muhammad; Housel, Gabrielle M.; Mcbride, Alexander; Kumbur, E. Caglan; Gogotsi, Yury

    2015-01-29

    Flow electrode deionization (FCDI) is an emerging area for continuous and scalable deionization, but the electrochemical and flow properties of the flow electrode need to be improved to minimize energy consumption. We examine chemical oxidation of granular activated carbon (AC) here to study the role of surface heteroatoms on rheology and electrochemical performance of a flow electrode (carbon slurry) for deionization processes. Moreover, it was demonstrated that higher mass densities could be used without increasing energy for pumping when using oxidized active material. High mass-loaded flow electrodes (28% carbon content) based on oxidized AC displayed similar viscosities (~21 Pa s) to lower mass-loaded flow electrodes (20% carbon content) based on nonoxidized AC. The 40% increased mass loading (from 20% to 28%) resulted in a 25% increase in flow electrode gravimetric capacitance (from 65 to 83 F g–1) without sacrificing flowability (viscosity). The electrical energy required to remove ~18% of the ions (desalt) from of the feed solution was observed to be significantly dependent on the mass loading and decreased (~60%) from 92 ± 7 to 28 ± 2.7 J with increased mass densities from 5 to 23 wt %. Finally, it is shown that the surface chemistry of the active material in a flow electrode effects the electrical and pumping energy requirements of a FCDI system.

  8. Effect of oxidation of carbon material on suspension electrodes for flow electrode capacitive deionization

    DOE PAGES

    Hatzell, Kelsey B.; Hatzell, Marta C.; Cook, Kevin M.; ...

    2015-01-29

    Flow electrode deionization (FCDI) is an emerging area for continuous and scalable deionization, but the electrochemical and flow properties of the flow electrode need to be improved to minimize energy consumption. We examine chemical oxidation of granular activated carbon (AC) here to study the role of surface heteroatoms on rheology and electrochemical performance of a flow electrode (carbon slurry) for deionization processes. Moreover, it was demonstrated that higher mass densities could be used without increasing energy for pumping when using oxidized active material. High mass-loaded flow electrodes (28% carbon content) based on oxidized AC displayed similar viscosities (~21 Pa s)more » to lower mass-loaded flow electrodes (20% carbon content) based on nonoxidized AC. The 40% increased mass loading (from 20% to 28%) resulted in a 25% increase in flow electrode gravimetric capacitance (from 65 to 83 F g–1) without sacrificing flowability (viscosity). The electrical energy required to remove ~18% of the ions (desalt) from of the feed solution was observed to be significantly dependent on the mass loading and decreased (~60%) from 92 ± 7 to 28 ± 2.7 J with increased mass densities from 5 to 23 wt %. Finally, it is shown that the surface chemistry of the active material in a flow electrode effects the electrical and pumping energy requirements of a FCDI system.« less

  9. Recirculating electric air filter

    DOEpatents

    Bergman, W.

    1985-01-09

    An electric air filter cartridge has a cylindrical inner high voltage electrode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

  10. Stability of carbon electrodes for aqueous lithium-air secondary batteries

    NASA Astrophysics Data System (ADS)

    Ohkuma, Hirokazu; Uechi, Ichiro; Matsui, Masaki; Takeda, Yasuo; Yamamoto, Osamu; Imanishi, Nobuyuki

    2014-01-01

    The air electrode performance of various carbon materials, such as Ketjen black (KB), acetylene black (AB and AB-S), Vulcan XC-72R (VX), and vapor grown carbon fiber (VGCF) with and without La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) catalyst were examined in an aqueous solution of saturated LiOH with 10 M LiCl in the current density range 0.2-2.0 mA cm-2. The best performance for oxygen reduction and evolution reactions was observed for the KB electrode, which has the highest surface area among the carbon materials examined. A steady over-potential of 0.2 V was obtained for the oxygen reduction reaction using the KB electrode without the catalyst, while the over-potential was 0.15 V for KB with the LSCF catalyst at 2.0 mA cm-2. The over-potentials for the oxygen evolution reaction were slightly higher than those for the oxygen reduction reaction, and gradually increased with the polarization period. Analysis of the gas in the cell after polarization above 0.4 V revealed the evolution of a small amount of CO during the oxygen evolution reaction by the decomposition of carbon in the electrode. The amount of CO evolved was significantly decreased by the addition of LSCF to the carbon electrode.

  11. Novel configuration of bifunctional air electrodes for rechargeable zinc-air batteries

    NASA Astrophysics Data System (ADS)

    Li, Po-Chieh; Chien, Yu-Ju; Hu, Chi-Chang

    2016-05-01

    A novel configuration of two electrodes containing electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) pressed into a bifunctional air electrode is designed for rechargeable Zn-air batteries. MOC/25BC carbon paper (MOC consisting of α-MnO2 and XC-72 carbon black) and Fe0.1Ni0.9Co2O4/Ti mesh on this air electrode mainly serve as the cathode for the ORR and the anode for the OER, respectively. The morphology and physicochemical properties of Fe0.1Ni0.9Co2O4 are investigated through scanning electron microscopy, inductively coupled plasma-mass spectrometry, and X-ray diffraction. Electrochemical studies comprise linear sweep voltammetry, rotating ring-disk electrode voltammetry, and the full-cell charge-discharge-cycling test. The discharge peak power density of the Zn-air battery with the unique air electrode reaches 88.8 mW cm-2 at 133.6 mA cm-2 and 0.66 V in an alkaline electrolyte under an ambient atmosphere. After 100 charge-discharge cycles at 10 mA cm-2, an increase of 0.3 V between charge and discharge cell voltages is observed. The deep charge-discharge curve (10 h in each step) indicates that the cell voltages of discharge (1.3 V) and charge (1.97 V) remain constant throughout the process. The performance of the proposed rechargeable Zn-air battery is superior to that of most other similar batteries reported in recent studies.

  12. Electrode materials for coal-fired MHD generators

    NASA Astrophysics Data System (ADS)

    Perkins, R. A.

    1980-10-01

    Metallic materials are evaluated as electrodes for coal fired MHD generators. A laboratory test that simulates the electrochemical and corrosive environment was developed and used to characterize electrode behavior in a diffuse current flow (nonarcing) mode of operation. High current density requires that an electron transport mechanism of current flow be maintained. With inert, stable electrodes, anode polarization occurs and ionic conduction prevails, limiting current to low values. The nature of this behavior and approaches to overcoming anodic polarization are studied as a function of electrode material, slag composition, and temperature. By operating at high temperatures and with controlled slag chemistries to produce a very fluid slag, depolarization may be achieved by mechanical mixing. Interrupted current flow are required to aid in breaking down anodic polarization.

  13. Investigation of electrode materials for alkaline batteries

    NASA Technical Reports Server (NTRS)

    Arcand, G. M.

    1971-01-01

    A number of amalgam electrode systems were investigated for possible use as high rate anodes and cathodes. The systems examined include: lithium, sodium, and potassium in Group 1, magnesium, calcium, and barium in Group 2, aluminum in Group 3, lead in Group 4, copper in Group 1b, and zinc and cadmium in Group 2b. The K(Hg) and Na(Hg) anodes in 10 VF and 15 VF (an unambiguous expression of concentration that indicates the number of formula weights of solute dissolved in a liter of solution) hydroxide solutions have proven satisfactory; some of these have produced current densities of more than 8 A/sq cm. None of the amalgam cathodes have approached this performance although the TI(Hg) has delivered 1 A/sq cm. Se(Hg) and Te(Hg) cathodes have given very stable discharges. Zn(Hg) and Cd(Hg) electrodes did not show good high rate characteristics, 200 to 300 mA/sq cm being about the maximum current densities obtainable. Both anodes are charged through a two-step process in which M(Hg) is first formed electrochemically and subsequently reduces Zn(II or Cd(II) to form the corresponding amalgam. The second step is extremely rapid for zinc and very slow for cadmium.

  14. Coaxial fiber supercapacitor using all-carbon material electrodes.

    PubMed

    Le, Viet Thong; Kim, Heetae; Ghosh, Arunabha; Kim, Jaesu; Chang, Jian; Vu, Quoc An; Pham, Duy Tho; Lee, Ju-Hyuck; Kim, Sang-Woo; Lee, Young Hee

    2013-07-23

    We report a coaxial fiber supercapacitor, which consists of carbon microfiber bundles coated with multiwalled carbon nanotubes as a core electrode and carbon nanofiber paper as an outer electrode. The ratio of electrode volumes was determined by a half-cell test of each electrode. The capacitance reached 6.3 mF cm(-1) (86.8 mF cm(-2)) at a core electrode diameter of 230 μm and the measured energy density was 0.7 μWh cm(-1) (9.8 μWh cm(-2)) at a power density of 13.7 μW cm(-1) (189.4 μW cm(-2)), which were much higher than the previous reports. The change in the cyclic voltammetry characteristics was negligible at 180° bending, with excellent cycling performance. The high capacitance, high energy density, and power density of the coaxial fiber supercapacitor are attributed to not only high effective surface area due to its coaxial structure and bundle of the core electrode, but also all-carbon materials electrodes which have high conductivity. Our coaxial fiber supercapacitor can promote the development of textile electronics in near future.

  15. Electrode materials and lithium battery systems

    DOEpatents

    Amine, Khalil; Belharouak, Ilias; Liu, Jun

    2011-06-28

    A material comprising a lithium titanate comprising a plurality of primary particles and secondary particles, wherein the average primary particle size is about 1 nm to about 500 nm and the average secondary particle size is about 1 .mu.m to about 4 .mu.m. In some embodiments the lithium titanate is carbon-coated. Also provided are methods of preparing lithium titanates, and devices using such materials.

  16. The rise of organic electrode materials for energy storage.

    PubMed

    Schon, Tyler B; McAllister, Bryony T; Li, Peng-Fei; Seferos, Dwight S

    2016-11-07

    Organic electrode materials are very attractive for electrochemical energy storage devices because they can be flexible, lightweight, low cost, benign to the environment, and used in a variety of device architectures. They are not mere alternatives to more traditional energy storage materials, rather, they have the potential to lead to disruptive technologies. Although organic electrode materials for energy storage have progressed in recent years, there are still significant challenges to overcome before reaching large-scale commercialization. This review provides an overview of energy storage systems as a whole, the metrics that are used to quantify the performance of electrodes, recent strategies that have been investigated to overcome the challenges associated with organic electrode materials, and the use of computational chemistry to design and study new materials and their properties. Design strategies are examined to overcome issues with capacity/capacitance, device voltage, rate capability, and cycling stability in order to guide future work in the area. The use of low cost materials is highlighted as a direction towards commercial realization.

  17. Polyanion‐Type Electrode Materials for Sodium‐Ion Batteries

    PubMed Central

    Ni, Qiao; Wu, Feng

    2017-01-01

    Sodium‐ion batteries, representative members of the post‐lithium‐battery club, are very attractive and promising for large‐scale energy storage applications. The increasing technological improvements in sodium‐ion batteries (Na‐ion batteries) are being driven by the demand for Na‐based electrode materials that are resource‐abundant, cost‐effective, and long lasting. Polyanion‐type compounds are among the most promising electrode materials for Na‐ion batteries due to their stability, safety, and suitable operating voltages. The most representative polyanion‐type electrode materials are Na3V2(PO4)3 and NaTi2(PO4)3 for Na‐based cathode and anode materials, respectively. Both show superior electrochemical properties and attractive prospects in terms of their development and application in Na‐ion batteries. Carbonophosphate Na3MnCO3PO4 and amorphous FePO4 have also recently emerged and are contributing to further developing the research scope of polyanion‐type Na‐ion batteries. However, the typical low conductivity and relatively low capacity performance of such materials still restrict their development. This paper presents a brief review of the research progress of polyanion‐type electrode materials for Na‐ion batteries, summarizing recent accomplishments, highlighting emerging strategies, and discussing the remaining challenges of such systems. PMID:28331782

  18. Polyanion-Type Electrode Materials for Sodium-Ion Batteries.

    PubMed

    Ni, Qiao; Bai, Ying; Wu, Feng; Wu, Chuan

    2017-03-01

    Sodium-ion batteries, representative members of the post-lithium-battery club, are very attractive and promising for large-scale energy storage applications. The increasing technological improvements in sodium-ion batteries (Na-ion batteries) are being driven by the demand for Na-based electrode materials that are resource-abundant, cost-effective, and long lasting. Polyanion-type compounds are among the most promising electrode materials for Na-ion batteries due to their stability, safety, and suitable operating voltages. The most representative polyanion-type electrode materials are Na3V2(PO4)3 and NaTi2(PO4)3 for Na-based cathode and anode materials, respectively. Both show superior electrochemical properties and attractive prospects in terms of their development and application in Na-ion batteries. Carbonophosphate Na3MnCO3PO4 and amorphous FePO4 have also recently emerged and are contributing to further developing the research scope of polyanion-type Na-ion batteries. However, the typical low conductivity and relatively low capacity performance of such materials still restrict their development. This paper presents a brief review of the research progress of polyanion-type electrode materials for Na-ion batteries, summarizing recent accomplishments, highlighting emerging strategies, and discussing the remaining challenges of such systems.

  19. Photocatalytic materials and technologies for air purification.

    PubMed

    Ren, Hangjuan; Koshy, Pramod; Chen, Wen-Fan; Qi, Shaohua; Sorrell, Charles Christopher

    2017-03-05

    Since there is increasing concern for the impact of air quality on human health, the present work surveys the materials and technologies for air purification using photocatalytic materials. The coverage includes (1) current photocatalytic materials for the decomposition of chemical contaminants and disinfection of pathogens present in air and (2) photocatalytic air purification systems that are used currently and under development. The present work focuses on five main themes. First, the mechanisms of photodegradation and photodisinfection are explained. Second, system designs for photocatalytic air purification are surveyed. Third, the photocatalytic materials used for air purification and their characteristics are considered, including both conventional and more recently developed photocatalysts. Fourth, the methods used to fabricate these materials are discussed. Fifth, the most significant coverage is devoted to materials design strategies aimed at improving the performance of photocatalysts for air purification. The review concludes with a brief consideration of promising future directions for materials research in photocatalysis.

  20. Carbon-based air electrodes carrying MnO 2 in zinc-air batteries

    NASA Astrophysics Data System (ADS)

    Wei, Zidong; Huang, Wenzhang; Zhang, Shengtao; Tan, Jun

    Catalysts prepared from the carbon black impregnated with manganous nitrate solution and then heated at temperature from 270°C to 450°C were investigated. It was found that the impregnated catalysts heated at temperature of 340°C exhibited the best catalytic activity for oxygen reduction in alkaline electrolyte. It was also found that the XRD spectra of pyrolytic MnO 2 from manganous nitrate over 340°C were different from those below 340°C. The enhanced catalysis of air electrodes was ascribed to the formation of MnO 2 crystal with d-value of 2.72 Å as the impregnated-catalysts was heated at temperature of 340°C. The other factors in preparation of air electrodes were also discussed.

  1. An improved bifunctional oxygen (air) electrode for reversible alkaline fuel cell systems and for rechargeable metal-air batteries

    NASA Astrophysics Data System (ADS)

    Kordesch, K.; Steininger, K.-H.; Tomantschger, K.

    1988-10-01

    Electrodes with a nickel layer of dual pore structure on the electrolyte side and a PTFE-bonded carbon layer on the oxygen (air) side are discussed, with application to space energy storage. During the electrolyis stage, the oxygen fills the large pores of the porous Ni structure with gas. During the discharge cycle, the iron/air or zinc/air cell of the carbon layer operates as a regular oxygen electrode.

  2. Organic Materials as Electrodes for Li-ion Batteries

    DTIC Science & Technology

    2015-09-04

    technology and research towards finding new materials to improve the performance are underway. Conductive organic polymers have been proposed as...indigo carmine conjugated carbonyl organic dye can be used for storing reversibly, both lithium and sodium ions for rechargeable battery applications ...Final 3. DATES COVERED (From - To) 15 May 2013 – 14 May 2015 4. TITLE AND SUBTITLE Organic materials as Electrodes for Li-ion Batteries

  3. Surface modification of active material structures in battery electrodes

    DOEpatents

    Erickson, Michael; Tikhonov, Konstantin

    2016-02-02

    Provided herein are methods of processing electrode active material structures for use in electrochemical cells or, more specifically, methods of forming surface layers on these structures. The structures are combined with a liquid to form a mixture. The mixture includes a surface reagent that chemically reacts and forms a surface layer covalently bound to the structures. The surface reagent may be a part of the initial liquid or added to the mixture after the liquid is combined with the structures. In some embodiments, the mixture may be processed to form a powder containing the structures with the surface layer thereon. Alternatively, the mixture may be deposited onto a current collecting substrate and dried to form an electrode layer. Furthermore, the liquid may be an electrolyte containing the surface reagent and a salt. The liquid soaks the previously arranged electrodes in order to contact the structures with the surface reagent.

  4. Sol-gel derived electrode materials for supercapacitor applications

    NASA Astrophysics Data System (ADS)

    Lin, Chuan

    1998-12-01

    Electrochemical capacitors have been receiving increasing interest in recent years for use in energy storage systems because of their high energy and power density and long cycle lifes. Possible applications of electrochemical capacitors include high power pulsed lasers, hybrid power system for electric vehicles, etc. In this dissertation, the preparation of electrode materials for use as electrochemical capacitors has been studied using the sol-gel process. The high surface area electrode materials explored in this work include a synthetic carbon xerogel for use in a double-layer capacitor, a cobalt oxide xerogel for use in a pseudocapacitor, and a carbon-ruthenium xerogel composite, which utilizes both double-layer and faradaic capacitances. The preparation conditions of these materials were investigated in detail to maximize the surface area and optimize the pore size so that more energy could be stored while minimizing mass transfer limitations. The microstructures of the materials were also correlated with their performance as electrochemical capacitors to improve their energy and power densities. Finally, an idealistic mathematical model, including both double-layer and faradaic processes, was developed and solved numerically. This model can be used to perform the parametric studies of an electrochemical capacitor so as to gain a better understanding of how the capacitor works and also how to improve cell operations and electrode materials design.

  5. Electrode material comprising graphene-composite materials in a graphite network

    DOEpatents

    Kung, Harold H.; Lee, Jung K.

    2014-07-15

    A durable electrode material suitable for use in Li ion batteries is provided. The material is comprised of a continuous network of graphite regions integrated with, and in good electrical contact with a composite comprising graphene sheets and an electrically active material, such as silicon, wherein the electrically active material is dispersed between, and supported by, the graphene sheets.

  6. Recirculating electric air filter

    DOEpatents

    Bergman, Werner

    1986-01-01

    An electric air filter cartridge has a cylindrical inner high voltage eleode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

  7. Method for making carbon super capacitor electrode materials

    DOEpatents

    Firsich, David W.; Ingersoll, David; Delnick, Frank M.

    1998-01-01

    A method for making near-net-shape, monolithic carbon electrodes for energy storage devices. The method includes the controlled pyrolysis and activation of a pressed shape of methyl cellulose powder with pyrolysis being carried out in two stages; pre-oxidation, preferably in air at a temperature between 200.degree.-250.degree. C., followed by carbonization under an inert atmosphere. An activation step to adjust the surface area of the carbon shape to a value desirable for the application being considered, including heating the carbon shape in an oxidizing atmosphere to a temperature of at least 300.degree. C., follows carbonization.

  8. Method for making carbon super capacitor electrode materials

    DOEpatents

    Firsich, D.W.; Ingersoll, D.; Delnick, F.M.

    1998-07-07

    A method is described for making near-net-shape, monolithic carbon electrodes for energy storage devices. The method includes the controlled pyrolysis and activation of a pressed shape of methyl cellulose powder with pyrolysis being carried out in two stages; pre-oxidation, preferably in air at a temperature between 200--250 C, followed by carbonization under an inert atmosphere. An activation step to adjust the surface area of the carbon shape to a value desirable for the application being considered, including heating the carbon shape in an oxidizing atmosphere to a temperature of at least 300 C, follows carbonization. 1 fig.

  9. 2D Hybrid Nanostructured Dirac Materials for Broadband Transparent Electrodes.

    PubMed

    Guo, Yunfan; Lin, Li; Zhao, Shuli; Deng, Bing; Chen, Hongliang; Ma, Bangjun; Wu, Jinxiong; Yin, Jianbo; Liu, Zhongfan; Peng, Hailin

    2015-08-05

    Broadband transparent electrodes based on 2D hybrid nanostructured Dirac materials between Bi2 Se3 and graphene are synthesized using a chemical vapor deposition (CVD) method. Bi2 Se3 nanoplates are preferentially grown along graphene grain boundaries as "smart" conductive patches to bridge the graphene boundary. These hybrid films increase by one- to threefold in conductivity while remaining highly transparent over broadband wavelength. They also display outstanding chemical stability and mechanical flexibility.

  10. Methods for making lithium vanadium oxide electrode materials

    DOEpatents

    Schutts, Scott M.; Kinney, Robert J.

    2000-01-01

    A method of making vanadium oxide formulations is presented. In one method of preparing lithium vanadium oxide for use as an electrode material, the method involves: admixing a particulate form of a lithium compound and a particulate form of a vanadium compound; jet milling the particulate admixture of the lithium and vanadium compounds; and heating the jet milled particulate admixture at a temperature below the melting temperature of the admixture to form lithium vanadium oxide.

  11. Positive Active Material For Alkaline Electrolyte Storage Battert Nickel Electrodes

    DOEpatents

    Bernard, Patrick; Baudry, Michelle

    2000-12-05

    A method of manufacturing a positive active material for nickel electrodes of alkaline storage batteries which consists of particles of hydroxide containing mainly nickel and covered with a layer of a hydroxide phase based on nickel and yttrium is disclosed. The proportion of the hydroxide phase is in the range 0.15% to 3% by weight of yttrium expressed as yttrium hydroxide relative to the total weight of particles.

  12. Material for electrodes of low temperature plasma generators

    DOEpatents

    Caplan, Malcolm; Vinogradov, Sergel Evge'evich; Ribin, Valeri Vasil'evich; Shekalov, Valentin Ivanovich; Rutberg, Philip Grigor'evich; Safronov, Alexi Anatol'evich

    2008-12-09

    Material for electrodes of low temperature plasma generators. The material contains a porous metal matrix impregnated with a material emitting electrons. The material uses a mixture of copper and iron powders as a porous metal matrix and a Group IIIB metal component such as Y.sub.2O.sub.3 is used as a material emitting electrons at, for example, the proportion of the components, mass %: iron: 3-30; Y.sub.2O.sub.3:0.05-1; copper: the remainder. Copper provides a high level of heat conduction and electric conductance, iron decreases intensity of copper evaporation in the process of plasma creation providing increased strength and lifetime, Y.sub.2O.sub.3 provides decreasing of electronic work function and stability of arc burning. The material can be used for producing the electrodes of low temperature AC plasma generators used for destruction of liquid organic wastes, medical wastes, and municipal wastes as well as for decontamination of low level radioactive waste, the destruction of chemical weapons, warfare toxic agents, etc.

  13. Material for electrodes of low temperature plasma generators

    DOEpatents

    Caplan, Malcolm; Vinogradov, Sergel Evge'evich; Ribin, Valeri Vasil'evich; Shekalov, Valentin Ivanovich; Rutberg, Philip Grigor'evich; Safronov, Alexi Anatol'evich; Shiryaev, Vasili Nikolaevich

    2010-03-02

    Material for electrodes of low temperature plasma generators. The material contains a porous metal matrix impregnated with a material emitting electrons. The material uses a mixture of copper and iron powders as a porous metal matrix and a Group IIIB metal component such as Y.sub.2O.sub.3 is used as a material emitting electrons at, for example, the proportion of the components, mass %: iron:3-30; Y.sub.2O.sub.3:0.05-1; copper: the remainder. Copper provides a high level of heat conduction and electric conductance, iron decreases intensity of copper evaporation in the process of plasma creation providing increased strength and lifetime, Y.sub.2O.sub.3 provides decreasing of electronic work function and stability of arc burning. The material can be used for producing the electrodes of low temperature AC plasma generators used for destruction of liquid organic wastes, medical wastes, municipal wastes as well as for decontamination of low level radioactive waste, the destruction of chemical weapons, warfare toxic agents, etc.

  14. Thick electrodes including nanoparticles having electroactive materials and methods of making same

    DOEpatents

    Xiao, Jie; Lu, Dongping; Liu, Jun; Zhang, Jiguang; Graff, Gordon L.

    2017-02-21

    Electrodes having nanostructure and/or utilizing nanoparticles of active materials and having high mass loadings of the active materials can be made to be physically robust and free of cracks and pinholes. The electrodes include nanoparticles having electroactive material, which nanoparticles are aggregated with carbon into larger secondary particles. The secondary particles can be bound with a binder to form the electrode.

  15. Investigation of Lithium-Air Battery Discharge Product Formed on Carbon Nanotube and Nanofiber Electrodes

    NASA Astrophysics Data System (ADS)

    Mitchell, Robert Revell, III

    Carbon nanotubes have been actively investigated for integration in a wide variety of applications since their discovery over 20 years ago. Their myriad desirable material properties including exceptional mechanical strength, high thermal conductivities, large surface-to-volume ratios, and considerable electrical conductivities, which are attributable to a quantum mechanical ability to conduct electrons ballistically, have continued to motivate interest in this material system. While a variety of synthesis techniques exist, carbon nanotubes and nanofibers are most often conveniently synthesized using chemical vapor deposition (CVD), which involves their catalyzed growth from transition metal nanoparticles. Vertically-aligned nanotube and nanofiber carpets produced using CVD have been utilized in a variety of applications including those related to energy storage. Li-air (Li-O2) batteries have received much interest recently because of their very high theoretical energy densities (3200 Wh/kgLi2O2 ). which make them ideal candidates for energy storage devices for future fully-electric vehicles. During operation of a Li-air battery O2 is reduced on the surface a porous air cathode, reacting with Li-ions to form lithium peroxide (Li-O2). Unlike the intercalation reactions of Li-ion batteries, discharge in a Li-air cell is analogous to an electrodeposition process involving the nucleation and growth of the depositing species on a foreign substrate. Carbon nanofiber electrodes were synthesized on porous substrates using a chemical vapor deposition process and then assembled into Li-O2 cells. The large surface to volume ratio and low density of carbon nanofiber electrodes were found to yield a very high gravimetric energy density in Li-O 2 cells, approaching 75% of the theoretical energy density for Li 2O2. Further, the carbon nanofiber electrodes were found to be excellent platforms for conducting ex situ electron microscopy investigations of the deposition Li2O2 phase

  16. High performance lithium insertion negative electrode materials for electrochemical devices

    NASA Astrophysics Data System (ADS)

    Channu, V. S. Reddy; Rambabu, B.; Kumari, Kusum; Kalluru, Rajmohan R.; Holze, Rudolf

    2016-11-01

    Spinel LiCrTiO4 oxides to be used as electrode materials for a lithium ion battery and an asymmetric supercapacitor were synthesized using a soft-chemical method with and without chelating agents followed by calcination at 700 °C for 10 h. Structural and morphological properties were studied with powder X-ray diffraction, scanning electron and transmission electron microscopy. Particles of 50-10 nm in size are observed in the microscopic images. The presence of Cr and Ti is confirmed from the EDS spectrum. Electrochemical properties of LiCrTiO4 electrode were examined in a lithium ion battery. The electrode prepared with oxalic acid-assisted LiCrTiO4 shows higher specific capacity.This LiCrTiO4 is also used as anode material for an asymmetric hybrid supercapacitor. The cell exhibits a specific capacity of 65 mAh/g at 1 mA/cm2. The specific capacity decreases with increasing current densities.

  17. Electrochemical Techniques for Intercalation Electrode Materials in Rechargeable Batteries.

    PubMed

    Zhu, Yujie; Gao, Tao; Fan, Xiulin; Han, Fudong; Wang, Chunsheng

    2017-03-16

    Understanding of the thermodynamic and kinetic properties of electrode materials is of great importance to develop new materials for high performance rechargeable batteries. Compared with computational understanding of physical and chemical properties of electrode materials, experimental methods provide direct and convenient evaluation of these properties. Often, the information gained from experimental work can not only offer feedback for the computational methods but also provide useful insights for improving the performance of materials. However, accurate experimental quantification of some properties can still be challenging. Among them, chemical diffusion coefficient is one representative example. It is one of the most crucial parameters determining the kinetics of intercalation compounds, which are by far the dominant electrode type used in rechargeable batteries. Therefore, it is of significance to quantitatively evaluate this parameter. For this purpose, various electrochemical techniques have been invented, for example, galvanostatic intermittent titration technique (GITT), potentiostatic intermittent titration technique (PITT), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). One salient advantage of these electrochemical techniques over other characterization techniques is that some implicit thermodynamic and kinetic quantities can be linked with the readily measurable electrical signals, current, and voltage, with very high precision. Nevertheless, proper application of these techniques requires not just an understanding of the structure and chemistry of the studied materials but sufficient knowledge of the physical model for ion transport within solid host materials and the analysis method to solve for chemical diffusion coefficient. Our group has been focusing on using various electrochemical techniques to investigate battery materials, as well as developing models for studying some emerging materials. In this Account, the

  18. Polyaniline nanostructures expedient as working electrode materials in supercapacitors

    NASA Astrophysics Data System (ADS)

    Gedela, Venkata Ramana; Srikanth, Vadali Venkata Satya Siva

    2014-04-01

    Granular type polyaniline (PANi), PANi nanofibers (NFs), and PANi nanotubes (NTs) expedient as working electrode materials for supercapacitors are synthesized. The synthesis procedure used in this work facilitates not only the synthesis of solid powders of the PANi nanostructures, but also thin films constituted by the same PANi nanostructures in the same experiment. PANi NFs are found to exhibit faster electrode kinetics and better capacitance when compared to PANi NTs and granular PANi. Specific capacitance and energy storage per unit mass of PANi NFs are 239.47 Fg-1 (at 0.5 Ag-1) and 43.2 Wh kg-1, respectively. Electrical conductivity of PANi NFs is also better when compared to the other two nanostructures. Properties of the three PANi nanostructures are explicated in correlation with crystallinity, intrinsic oxidation state, doping degree, BET surface area, and ordered mesoporosity pertaining to the nanostructures.

  19. Performance and microbial ecology of air-cathode microbial fuel cells with layered electrode assemblies.

    PubMed

    Butler, Caitlyn S; Nerenberg, Robert

    2010-05-01

    Microbial fuel cells (MFCs) can be built with layered electrode assemblies, where the anode, proton exchange membrane (PEM), and cathode are pressed into a single unit. We studied the performance and microbial community structure of MFCs with layered assemblies, addressing the effect of materials and oxygen crossover on the community structure. Four MFCs with layered assemblies were constructed using Nafion or Ultrex PEMs and a plain carbon cloth electrode or a cathode with an oxygen-resistant polytetrafluoroethylene diffusion layer. The MFC with Nafion PEM and cathode diffusion layer achieved the highest power density, 381 mW/m(2) (20 W/m(3)). The rates of oxygen diffusion from cathode to anode were three times higher in the MFCs with plain cathodes compared to those with diffusion-layer cathodes. Microsensor studies revealed little accumulation of oxygen within the anode cloth. However, the abundance of bacteria known to use oxygen as an electron acceptor, but not known to have exoelectrogenic activity, was greater in MFCs with plain cathodes. The MFCs with diffusion-layer cathodes had high abundance of exoelectrogenic bacteria within the genus Geobacter. This work suggests that cathode materials can significantly influence oxygen crossover and the relative abundance of exoelectrogenic bacteria on the anode, while PEM materials have little influence on anode community structure. Our results show that oxygen crossover can significantly decrease the performance of air-cathode MFCs with layered assemblies, and therefore limiting crossover may be of particular importance for these types of MFCs.

  20. Spiral configuration of electrodes and dielectric material for sensing an environmental property

    NASA Technical Reports Server (NTRS)

    Laue, Eric G. (Inventor); Stephens, James B. (Inventor)

    1989-01-01

    A reliable moisture-indicating capactive sensor is provided with wire electrodes at least one of which includes a coating of moisture-absorbing dielectric material by spirally twisting the wire electrodes about each other, thereby establishing a pair of electrodes in contact with opposite surfaces of a layer of dielectric material, and assuring consistent contact of each electrode with the dielectric material despite changes in environmental conditions.

  1. Gradient porous electrode architectures for rechargeable metal-air batteries

    DOEpatents

    Dudney, Nancy J.; Klett, James W.; Nanda, Jagjit; Narula, Chaitanya Kumar; Pannala, Sreekanth

    2016-03-22

    A cathode for a metal air battery includes a cathode structure having pores. The cathode structure has a metal side and an air side. The porosity decreases from the air side to the metal side. A metal air battery and a method of making a cathode for a metal air battery are also disclosed.

  2. Alternate electrode materials for the SP100 reactor. Final report

    SciTech Connect

    Randich, E.

    1992-05-01

    This work was performed in response to a request by the Astro-Space Division of the General Electric Co. to develop alternate electrodes materials for the electrodes of the PD2 modules to be used in the SP100 thermoelectric power conversion system. Initially, the project consisted of four tasks: (1) development of a ZrB{sub 2} (C) CVD coating on SiMo substrates, (2) development of a ZrB{sub 2} (C) CVD coating on SiGe substrates, (3) development of CVI W for porous graphite electrodes, and (4) technology transfer of pertinent developed processes. The project evolved initially into developing only ZrB{sub 2} coatings on SiGe and graphite substrates, and later into developing ZrB{sub 2} coatings only on graphite substrates. Several sizes of graphite and pyrolytic carbon-coated graphite substrates were coated with ZrB{sub 2} during the project. For budgetary reasons, the project was terminated after half the allotted time had passed. Apart from the production of coated specimens for evaluation, the major accomplishment of the project was the development of the CVD processing to produce the desired coatings.

  3. Anodes - Materials for negative electrodes in electrochemical energy technology

    NASA Astrophysics Data System (ADS)

    Holze, Rudolf

    2014-06-01

    The basic concepts of electrodes and electrochemical cells (including both galvanic and electrolytic ones) are introduced and illustrated with practical examples. Particular attention is paid to negative electrodes in primary and secondary cells, fuel cell electrodes and electrodes in redox flow batteries. General features and arguments pertaining to selection, optimization and further development are highlighted.

  4. Electrode electrolyte interlayers containing cerium oxide for electrochemical fuel cells

    DOEpatents

    Borglum, Brian P.; Bessette, Norman F.

    2000-01-01

    An electrochemical cell is made having a porous fuel electrode (16) and a porous air electrode (13), with solid oxide electrolyte (15) therebetween, where the air electrode surface opposing the electrolyte has a separate, attached, dense, continuous layer (14) of a material containing cerium oxide, and where electrolyte (16) contacts the continuous oxide layer (14), without contacting the air electrode (13).

  5. Improved Positive Electrode Materials for Lithium-ion Batteries

    NASA Astrophysics Data System (ADS)

    Conry, Thomas Edward

    The introduction of the first commercially produced Li-ion battery by Sony in 1990 sparked a period of unprecedented growth in the consumer electronics industry. Now, with increasing efforts to move away from fossil-fuel-derived energy sources, a substantial amount of current research is focused on the development of an electrified transportation fleet. Unfortunately, existent battery technologies are unable to provide the necessary performance for electric vehicles (EV's) and plug-in hybrid electric vehicles (PHEV's) vehicles at a competitive cost. The cost and performance metrics of current Li-ion batteries are mainly determined by the positive electrode materials. The work here is concerned with understanding the structural and electrochemical consequences of cost-lowering mechanisms in two separate classes of Li-ion cathode materials; the LiMO2 (M = Ni, Mn, Co) layered oxides and the LiMPO4 olivine materials; with the goal of improving performance. Al-substitution for Co in LiNizMnzCo1-2zO 2 ("NMC") materials not only decreases the costly Co-content, but also improves the safety aspects and, notably, enhances the cycling stability of the layered oxide electrodes. The structural and electrochemical effects of Al-substitution are investigated here in a model NMC compound, LiNi0.45 Mn0.45Co0.1-yAlyO2. In addition to electrochemical measurements, various synchrotron-based characterization methods are utilized, including high-resolution X-ray diffraction (XRD), in situ X-ray diffraction, and X-ray absorption spectroscopy (XAS). Al-substitution causes a slight distortion of the as-synthesized hexagonal layered oxide lattice, lowering the inherent octahedral strain within the transition metal layer. The presence of Al also is observed to limit the structural variation of the NMC materials upon Li-deintercalation, as well as extended cycling of the electrodes. Various olivine materials, Li

  6. Application of infrared spectroscopy to monitoring gas insulated high-voltage equipment: electrode material-dependent SF(6) decomposition.

    PubMed

    Kurte, R; Beyer, C; Heise, H M; Klockow, D

    2002-08-01

    Sulfur hexafluoride is a chemically inert gas which is used in gas insulated substations (GIS) and other high-voltage equipment, leading to a significant enhancement of apparatus lifetime and reductions in installation size and maintenance requirements compared to conventional air insulated substations. However, component failures due to aging of the gas through electrical discharges may occur, and on-site monitoring for risk assessment is needed. Infrared spectroscopy was used for the analysis of gaseous by-products generated from electrical discharges in sulfur hexafluoride gas. An infrared monitoring system was developed using a micro-cell coupled to an FTIR spectrometer by silver halide fibers. Partial least-squares calibration was applied by using a limited number of optimally selected spectral variables. Emphasis was placed on the determination of main decomposition products, such as SOF(2), SOF(4), and SO(2)F(2). Besides the different electrical conditions, the material of the plane counter electrode of the discharge chamber was also varied between silver, aluminum, copper, tungsten, or tungsten/copper alloy. For the spark experiments the point electrode was the same material as chosen for the plane electrode, whereas for partial discharges a stainless steel needle was employed. Complementary investigations on the chemical composition within the solid counter electrode material by secondary neutral mass spectrometry (SNMS) were also carried out. Under sparking conditions, the electrode material plays an important role in the decomposition rates of the gas-phase, but no relevant material dependence could be observed under partial discharge conditions.

  7. Nanostructured Mo-based electrode materials for electrochemical energy storage.

    PubMed

    Hu, Xianluo; Zhang, Wei; Liu, Xiaoxiao; Mei, Yueni; Huang, Yunhui

    2015-04-21

    The development of advanced energy storage devices is at the forefront of research geared towards a sustainable future. Nanostructured materials are advantageous in offering huge surface to volume ratios, favorable transport features, and attractive physicochemical properties. They have been extensively explored in various fields of energy storage and conversion. This review is focused largely on the recent progress in nanostructured Mo-based electrode materials including molybdenum oxides (MoO(x), 2 ≤ x ≤ 3), dichalconides (MoX2, X = S, Se), and oxysalts for rechargeable lithium/sodium-ion batteries, Mg batteries, and supercapacitors. Mo-based compounds including MoO2, MoO3, MoO(3-y) (0 < y < 1), MMo(x)O(y) (M = Fe, Co, Ni, Ca, Mn, Zn, Mg, or Cd; x = 1, y = 4; x = 3, y = 8), MoS2, MoSe2, (MoO2)2P2O7, LiMoO2, Li2MoO3, etc. possess multiple valence states and exhibit rich chemistry. They are very attractive candidates for efficient electrochemical energy storage systems because of their unique physicochemical properties, such as conductivity, mechanical and thermal stability, and cyclability. In this review, we aim to provide a systematic summary of the synthesis, modification, and electrochemical performance of nanostructured Mo-based compounds, as well as their energy storage applications in lithium/sodium-ion batteries, Mg batteries, and pseudocapacitors. The relationship between nanoarchitectures and electrochemical performances as well as the related charge-storage mechanism is discussed. Moreover, remarks on the challenges and perspectives of Mo-containing compounds for further development in electrochemical energy storage applications are proposed. This review sheds light on the sustainable development of advanced rechargeable batteries and supercapacitors with nanostructured Mo-based electrode materials.

  8. Surface modifications of electrode materials for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Fu, L. J.; Liu, H.; Li, C.; Wu, Y. P.; Rahm, E.; Holze, R.; Wu, H. Q.

    2006-02-01

    Since the birth of the lithium ion battery in the early 1990s, its development has been very rapid and it has been widely applied as power source for a lot of light and high value electronics due to its significant advantages over traditional rechargeable battery systems. Recent research demonstrates the importance of surface structural features of electrode materials for their electrochemical performance, and in this paper the latest progress on this aspect is reviewed. Electrode materials are either anodic or cathodic ones. The former mainly include graphitic carbons, whose surfaces can be modified by mild oxidation, deposition of metals and metal oxides, coating with polymers and other kinds of carbons. Through these modifications, the surface structures of the graphitic carbon anodes are improved, and these improvements include: (1) smoothing the active edge surfaces by removing some reactive sites and/or defects on the graphite surface, (2) forming a dense oxide layer on the graphite surface, and (3) covering active edge structures on the graphite surface. Meanwhile, other accompanying changes occur: (1) production of nanochannels/micropores, (2) an increase in the electronic conductivity, (3) an inhibition of structural changes during cycling, (4) a reduction of the thickness of the SEI (solid-electrolyte-interface) layer, and (5) an increase in the number of host sites for lithium storage. As a result, the direct contact of graphite with the electrolyte solution is prevented, its surface reactivity with electrolytes, the decomposition of electrolytes, the co-intercalation of the solvated lithium ions and the charge-transfer resistance are decreased, and the movement of graphene sheets is inhibited. When the surfaces of cathode materials, mainly including LiCoO 2, LiNiO 2 and LiMn 2O 4, are coated with oxides such as MgO, Al 2O 3, ZnO, SnO 2, ZrO 2, Li 2Oṡ2B 2O 3 glass and other electroactive oxides, the coating can prevent their direct contact with the

  9. A study of the glow discharge characteristics of contact electrodes at atmospheric pressure in air

    SciTech Connect

    Liu, Wenzheng Sun, Guangliang Li, Chuanhui; Zhang, Rongrong

    2014-04-15

    Electric field distributions and discharge properties of rod-rod contact electrodes were studied under the condition of DBD for the steady generation of atmospheric pressure glow discharge plasma (APGD) in air. We found that under the effect of the initial electrons generated in a nanometer-scale gap, the rod-rod cross-contact electrodes yielded APGD plasma in air. Regarding the rod-rod cross-contact electrodes, increasing the working voltage expanded the strong electric field area of the gas gap so that both discharge area and discharge power increased, and the increase in the number of contact points kept the initial discharge voltage unchanged and caused an increase in the plasma discharge area and discharge power. A mesh-like structure of cross-contact electrodes was designed and used to generate more APGD plasma, suggesting high applicability.

  10. Work function determination of promising electrode materials for thermionic converters

    NASA Technical Reports Server (NTRS)

    Jacobson, D.

    1977-01-01

    Work performed on this contract was primarily for the evaluation of selected electrode materials for thermionic energy converters. The original objective was to characterize selected nickel based superalloys up to temperatures of 1400 K. It was found that an early selection, Inconel 800 produced a high vapor pressure which interfered with the vacuum emission measurements. The program then shifted to two other areas. The first area was to obtain emission from the superalloys in a cesiated atmosphere. The cesium plasma helps to suppress the vaporization interference. The second area involved characterization of the Lanthanum-Boron series as thermionic emitters. These final two areas resulted in three journal publications which are attached to this report.

  11. Rechargeable Lithium-Air Batteries: Development of Ultra High Specific Energy Rechargeable Lithium-Air Batteries Based on Protected Lithium Metal Electrodes

    SciTech Connect

    2010-07-01

    BEEST Project: PolyPlus is developing the world’s first commercially available rechargeable lithium-air (Li-Air) battery. Li-Air batteries are better than the Li-Ion batteries used in most EVs today because they breathe in air from the atmosphere for use as an active material in the battery, which greatly decreases its weight. Li-Air batteries also store nearly 700% as much energy as traditional Li-Ion batteries. A lighter battery would improve the range of EVs dramatically. Polyplus is on track to making a critical breakthrough: the first manufacturable protective membrane between its lithium–based negative electrode and the reaction chamber where it reacts with oxygen from the air. This gives the battery the unique ability to recharge by moving lithium in and out of the battery’s reaction chamber for storage until the battery needs to discharge once again. Until now, engineers had been unable to create the complex packaging and air-breathing components required to turn Li-Air batteries into rechargeable systems.

  12. Drop detachment and motion on fuel cell electrode materials.

    PubMed

    Gauthier, Eric; Hellstern, Thomas; Kevrekidis, Ioannis G; Benziger, Jay

    2012-02-01

    Liquid water is pushed through flow channels of fuel cells, where one surface is a porous carbon electrode made up of carbon fibers. Water drops grow on the fibrous carbon surface in the gas flow channel. The drops adhere to the superficial fiber surfaces but exhibit little penetration into the voids between the fibers. The fibrous surfaces are hydrophobic, but there is a substantial threshold force necessary to initiate water drop motion. Once the water drops begin to move, however, the adhesive force decreases and drops move with minimal friction, similar to motion on superhydrophobic materials. We report here studies of water wetting and water drop motion on typical porous carbon materials (carbon paper and carbon cloth) employed in fuel cells. The static coefficient of friction on these textured surfaces is comparable to that for smooth Teflon. But the dynamic coefficient of friction is several orders of magnitude smaller on the textured surfaces than on smooth Teflon. Carbon cloth displays a much smaller static contact angle hysteresis than carbon paper due to its two-scale roughness. The dynamic contact angle hysteresis for carbon paper is greatly reduced compared to the static contact angle hysteresis. Enhanced dynamic hydrophobicity is suggested to result from the extent to which a dynamic contact line can track topological heterogeneities of the liquid/solid interface.

  13. Fabrication of a three-electrode battery using hydrogen-storage materials

    NASA Astrophysics Data System (ADS)

    Roh, Chi-Woo; Seo, Jung-Yong; Moon, Hyung-Seok; Park, Hyun-Young; Nam, Na-Yun; Cho, Sung Min; Yoo, Pil J.; Chung, Chan-Hwa

    2015-04-01

    In this study, an energy storage device using a three-electrode battery is fabricated. The charging process takes place during electrolysis of the alkaline electrolyte where hydrogen is stored at the palladium bifunctional electrode. Upon discharging, power is generated by operating the alkaline fuel cell using hydrogen which is accumulated in the palladium hydride bifunctional electrode during the charging process. The bifunctional palladium electrode is prepared by electrodeposition using a hydrogen bubble template followed by a galvanic displacement reaction of platinum in order to functionalize the electrode to work not only as a hydrogen storage material but also as an anode in a fuel cell. This bifunctional electrode has a sufficiently high surface area and the platinum catalyst populates at the surface of electrode to operate the fuel cell. The charging and discharging performance of the three-electrode battery are characterized. In addition, the cycle stability is investigated.

  14. Electrode-active material for electrochemical batteries and method of preparation

    DOEpatents

    Varma, Ravi

    1987-01-01

    A battery electrode material comprising a non-stoichiometric electrode-active material which forms a redox pair with the battery electrolyte, an electrically conductive polymer present in the range of from about 2% by weight to about 5% by weight of the electrode-active material, and a binder. The conductive polymer provides improved proton or ion conductivity and is a ligand resulting in metal ion or negative ion vacancies of less than about 0.1 atom percent. Specific electrodes of nickel and lead are disclosed.

  15. Building materials and indoor air quality.

    PubMed

    Levin, H

    1989-01-01

    New building materials, products, and furnishings are known to emit a large number of organic chemicals into indoor air. The author addresses the effects of volatile organic compounds (VOCs) on building occupants, including building materials evaluation and strategies to reduce airborne concentrations. A major problem is that little is known about the specific health effects of most VOCs at the low concentrations usually found in indoor environments.

  16. Graphene Oxide Involved Air-Controlled Electrospray for Uniform, Fast, Instantly Dry, and Binder-Free Electrode Fabrication.

    PubMed

    Fei, Ling; Yoo, Sang Ha; Villamayor, Rachel Ann R; Williams, Brian P; Gong, Seon Young; Park, Sunchan; Shin, Kyusoon; Joo, Yong Lak

    2017-03-22

    We report a facile air-controlled electrospray method to directly deposit binder-free active materials/graphene oxide (GO) onto current collectors. This method is inspired from an electrospinning process, and possesses all the advantages that electrospinning has such as low cost, easy scaling up, and simultaneous solvent evaporation during the spraying process. Moreover, the spray slurry is only a simple mixture of active materials and GO suspension in water, no binder polymer, organic solvent, and conductive carbon required. In our research, high-capacity Si nanoparticles (Si NP, 70-100 nm) and SiO microparticles (SiO MP, 3-10 μm) were selected to demonstrate the capability of this method to accommodate particles with different sizes. Their mixture with GO was sprayed onto a collector and then thermally annealed in an inert gas to obtain Si NP or SiO MP/reduced graphene oxide (RGO) binder-free electrodes. We are also able to directly deposit fairly large electrode sheets (e.g., 12 × 21 in.) upon the application requirement. To the best of our knowledge, this is the simplest approach to produce Si-related materials/RGO layered structures directly on current collector with controllable area and loading. Si and SiO MP/RGO are evaluated in both half and full lithium cells, showing good electrochemical performance. Prelithiation is also studied and gives a high first cycle Coulombic efficiency. In addition to Si-related materials, other materials with different shapes and sizes (e.g., MoO3 nanobelts, Sn/carbon nanofibers, and commercial sulfur particles) can also be sprayed. Beyond the preparation of battery electrodes, this approach can also be applied for other types of electrode preparation such as that of a supercapacitor, fuel cell, and solar cell.

  17. Effects of Electrode Material on the Voltage of a Tree-Based Energy Generator

    PubMed Central

    2015-01-01

    The voltage between a standing tree and its surrounding soil is regarded as an innovative renewable energy source. This source is expected to provide a new power generation system for the low-power electrical equipment used in forestry. However, the voltage is weak, which has caused great difficulty in application. Consequently, the development of a method to increase the voltage is a key issue that must be addressed in this area of applied research. As the front-end component for energy harvesting, a metal electrode has a material effect on the level and stability of the voltage obtained. This study aimed to preliminarily ascertain the rules and mechanisms that underlie the effects of electrode material on voltage. Electrodes of different materials were used to measure the tree-source voltage, and the data were employed in a comparative analysis. The results indicate that the conductivity of the metal electrode significantly affects the contact resistance of the electrode-soil and electrode-trunk contact surfaces, thereby influencing the voltage level. The metal reactivity of the electrode has no significant effect on the voltage. However, passivation of the electrode materials markedly reduces the voltage. Suitable electrode materials are demonstrated and recommended. PMID:26302491

  18. Effects of Electrode Material on the Voltage of a Tree-Based Energy Generator.

    PubMed

    Hao, Zhibin; Wang, Guozhu; Li, Wenbin; Zhang, Junguo; Kan, Jiangming

    2015-01-01

    The voltage between a standing tree and its surrounding soil is regarded as an innovative renewable energy source. This source is expected to provide a new power generation system for the low-power electrical equipment used in forestry. However, the voltage is weak, which has caused great difficulty in application. Consequently, the development of a method to increase the voltage is a key issue that must be addressed in this area of applied research. As the front-end component for energy harvesting, a metal electrode has a material effect on the level and stability of the voltage obtained. This study aimed to preliminarily ascertain the rules and mechanisms that underlie the effects of electrode material on voltage. Electrodes of different materials were used to measure the tree-source voltage, and the data were employed in a comparative analysis. The results indicate that the conductivity of the metal electrode significantly affects the contact resistance of the electrode-soil and electrode-trunk contact surfaces, thereby influencing the voltage level. The metal reactivity of the electrode has no significant effect on the voltage. However, passivation of the electrode materials markedly reduces the voltage. Suitable electrode materials are demonstrated and recommended.

  19. Fuel Cell Electrodes for Hydrogen-Air Fuel Cell Assemblies.

    DTIC Science & Technology

    The report describes the design and evaluation of a hydrogen-air fuel cell module for use in a portable hydrid fuel cell -battery system. The fuel ... cell module consists of a stack of 20 single assemblies. Each assembly contains 2 electrically independent cells with a common electrolyte compartment

  20. Recent research progress on iron- and manganese-based positive electrode materials for rechargeable sodium batteries

    PubMed Central

    Yabuuchi, Naoaki; Komaba, Shinichi

    2014-01-01

    Large-scale high-energy batteries with electrode materials made from the Earth-abundant elements are needed to achieve sustainable energy development. On the basis of material abundance, rechargeable sodium batteries with iron- and manganese-based positive electrode materials are the ideal candidates for large-scale batteries. In this review, iron- and manganese-based electrode materials, oxides, phosphates, fluorides, etc, as positive electrodes for rechargeable sodium batteries are reviewed. Iron and manganese compounds with sodium ions provide high structural flexibility. Two layered polymorphs, O3- and P2-type layered structures, show different electrode performance in Na cells related to the different phase transition and sodium migration processes on sodium extraction/insertion. Similar to layered oxides, iron/manganese phosphates and pyrophosphates also provide the different framework structures, which are used as sodium insertion host materials. Electrode performance and reaction mechanisms of the iron- and manganese-based electrode materials in Na cells are described and the similarities and differences with lithium counterparts are also discussed. Together with these results, the possibility of the high-energy battery system with electrode materials made from only Earth-abundant elements is reviewed. PMID:27877694

  1. Recent research progress on iron- and manganese-based positive electrode materials for rechargeable sodium batteries.

    PubMed

    Yabuuchi, Naoaki; Komaba, Shinichi

    2014-08-01

    Large-scale high-energy batteries with electrode materials made from the Earth-abundant elements are needed to achieve sustainable energy development. On the basis of material abundance, rechargeable sodium batteries with iron- and manganese-based positive electrode materials are the ideal candidates for large-scale batteries. In this review, iron- and manganese-based electrode materials, oxides, phosphates, fluorides, etc, as positive electrodes for rechargeable sodium batteries are reviewed. Iron and manganese compounds with sodium ions provide high structural flexibility. Two layered polymorphs, O3- and P2-type layered structures, show different electrode performance in Na cells related to the different phase transition and sodium migration processes on sodium extraction/insertion. Similar to layered oxides, iron/manganese phosphates and pyrophosphates also provide the different framework structures, which are used as sodium insertion host materials. Electrode performance and reaction mechanisms of the iron- and manganese-based electrode materials in Na cells are described and the similarities and differences with lithium counterparts are also discussed. Together with these results, the possibility of the high-energy battery system with electrode materials made from only Earth-abundant elements is reviewed.

  2. Recent research progress on iron- and manganese-based positive electrode materials for rechargeable sodium batteries

    NASA Astrophysics Data System (ADS)

    Yabuuchi, Naoaki; Komaba, Shinichi

    2014-08-01

    Large-scale high-energy batteries with electrode materials made from the Earth-abundant elements are needed to achieve sustainable energy development. On the basis of material abundance, rechargeable sodium batteries with iron- and manganese-based positive electrode materials are the ideal candidates for large-scale batteries. In this review, iron- and manganese-based electrode materials, oxides, phosphates, fluorides, etc, as positive electrodes for rechargeable sodium batteries are reviewed. Iron and manganese compounds with sodium ions provide high structural flexibility. Two layered polymorphs, O3- and P2-type layered structures, show different electrode performance in Na cells related to the different phase transition and sodium migration processes on sodium extraction/insertion. Similar to layered oxides, iron/manganese phosphates and pyrophosphates also provide the different framework structures, which are used as sodium insertion host materials. Electrode performance and reaction mechanisms of the iron- and manganese-based electrode materials in Na cells are described and the similarities and differences with lithium counterparts are also discussed. Together with these results, the possibility of the high-energy battery system with electrode materials made from only Earth-abundant elements is reviewed.

  3. Monte Carlo modelling the dosimetric effects of electrode material on diamond detectors.

    PubMed

    Baluti, Florentina; Deloar, Hossain M; Lansley, Stuart P; Meyer, Juergen

    2015-03-01

    Diamond detectors for radiation dosimetry were modelled using the EGSnrc Monte Carlo code to investigate the influence of electrode material and detector orientation on the absorbed dose. The small dimensions of the electrode/diamond/electrode detector structure required very thin voxels and the use of non-standard DOSXYZnrc Monte Carlo model parameters. The interface phenomena was investigated by simulating a 6 MV beam and detectors with different electrode materials, namely Al, Ag, Cu and Au, with thickens of 0.1 µm for the electrodes and 0.1 mm for the diamond, in both perpendicular and parallel detector orientation with regards to the incident beam. The smallest perturbations were observed for the parallel detector orientation and Al electrodes (Z = 13). In summary, EGSnrc Monte Carlo code is well suited for modelling small detector geometries. The Monte Carlo model developed is a useful tool to investigate the dosimetric effects caused by different electrode materials. To minimise perturbations cause by the detector electrodes, it is recommended that the electrodes should be made from a low-atomic number material and placed parallel to the beam direction.

  4. Nanostructured electrode materials for Li-ion battery

    NASA Astrophysics Data System (ADS)

    Balaya, Palani; Saravanan, Kuppan; Hariharan, Srirama

    2010-04-01

    Nanostructured materials have triggered a great excitement in recent times due to both fundamental interest as well as technological impact relevant for lithium ion batteries (LIBs). Size reduction in nanocrystals leads to a variety of unexpected exciting phenomena due to enhanced surface-to-volume ratio and reduced transport length. We will consider a few examples of nanostructured electrode materials in the context of lithium batteries for achieving high storage and high rate performances: 1) LiFePO4 nanoplates synthesized using solvothermal method could store Li-ions comparable to its theoretical capacity at C/10, while at 30C, they exhibit storage capacity up to 45 mAh/g. Size reduction (~30 nm) at the b-axis favors the fast Li-ion diffusion. In addition to this, uniform ~5 nm carbon coating throughout the plates provides excellent electronically conducting path for electrons. This nano architecture enables fast insertion/extraction of both Li-ions as well as electrons; 2) Mesporous-TiO2 with high surface area (135m2/g) synthesized using soft-template method exhibits high volumetric density compared to commercial nanopowder (P25), with excellent Li-storage behavior. C16 meso-TiO2 synthesized from CTAB exhibits reversible storage capacity of 288mAh/g at 0.2C and 109 mAh/g at 30C; 3) Zero strain Li4Ti5O12 anode material has been synthesized using several wet chemical routes. The best condition has been optimized to achieve storage capability close to theoretical limit of 175mAh/g at C/10. At 10C, we could retain lithium storage up to 88 mAh/g; 4) We report our recent results on α-Fe2O3 and γ-Fe2O3 using conversion reaction, providing insight for a better storage capability in γ-phase than the α-phase at 2C resulting solely from the nanocrystallinity.

  5. Effects of atmospheric air plasma treatment of graphite and carbon felt electrodes on the anodic current from Shewanella attached cells.

    PubMed

    Epifanio, Monica; Inguva, Saikumar; Kitching, Michael; Mosnier, Jean-Paul; Marsili, Enrico

    2015-12-01

    The attachment of electrochemically active microorganisms (EAM) on an electrode is determined by both the chemistry and topography of the electrode surface. Pre-treatment of the electrode surface by atmospheric air plasma introduces hydrophilic functional groups, thereby increasing cell attachment and electroactivity in short-term experiments. In this study, we use graphite and carbon felt electrodes to grow the model EAM Shewanella loihica PV-4 at oxidative potential (0.2 V vs. Ag/AgCl). Cell attachment and electroactivity are measured through electrodynamic methods. Atmospheric air plasma pre-treatment increases cell attachment and current output at graphite electrodes by 25%, while it improves the electroactivity of the carbon felt electrodes by 450%. Air plasma pre-treatment decreased the coulombic efficiency on both carbon felt and graphite electrodes by 60% and 80%, respectively. Microbially produced flavins adsorb preferentially at the graphite electrode, and air plasma pre-treatment results in lower flavin adsorption at both graphite and carbon felt electrodes. Results show that air plasma pre-treatment is a feasible option to increase current output in bioelectrochemical systems.

  6. Ultra-fast dry microwave preparation of SnSb used as negative electrode material for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Antitomaso, P.; Fraisse, B.; Sougrati, M. T.; Morato-Lallemand, F.; Biscaglia, S.; Aymé-Perrot, D.; Girard, P.; Monconduit, L.

    2016-09-01

    Tin antimonide alloy was obtained for the first time using a very simple dry microwave route. Up to 1 g of well crystallized SnSb can be easily prepared in 90 s under air in an open crucible. A full characterization by X-ray diffraction and 119Sn Mössbauer spectroscopy demonstrated the benefit of carbon as susceptor, which avoid any oxide contamination. The microwave-prepared SnSb was tested as negative electrode material in Li batteries. Interesting results in terms of capacity and rate capability were obtained with up to 700 mAh/g sustained after 50 cycles at variable current. These results pave the way for the introduction of microwave synthesis as realistic route for a rapid, low cost and up-scalable production of electrode material for Li batteries or other large scale application types.

  7. Metallic sulfide additives for positive electrode material within a secondary electrochemical cell

    DOEpatents

    Walsh, William J.; McPheeters, Charles C.; Yao, Neng-ping; Koura, Kobuyuki

    1976-01-01

    An improved active material for use within the positive electrode of a secondary electrochemical cell includes a mixture of iron disulfide and a sulfide of a polyvalent metal. Various metal sulfides, particularly sulfides of cobalt, nickel, copper, cerium and manganese, are added in minor weight proportion in respect to iron disulfide for improving the electrode performance and reducing current collector requirements.

  8. Method for determining trace quantities of chloride in polymeric materials using ion selective electrodes: Final report

    SciTech Connect

    Salary, J.

    1987-02-01

    A method for determining trace quantities of chloride in polymeric materials has been developed. Ion-selective electrodes and the standard addition method were used in all the analyses. The ion-selective electrode method was compared with neutron activation, ion chromatography and chloridometer titration. The ion-selective electrode technique results for chloride were similar to those of neutron activation, which is the acknowledged referee method. This ion-selective electrode method showed the highest standard recovery when compared with the ion chromatography and chloridometer titration methods.

  9. Layered perovskite oxide: a reversible air electrode for oxygen evolution/reduction in rechargeable metal-air batteries.

    PubMed

    Takeguchi, Tatsuya; Yamanaka, Toshiro; Takahashi, Hiroki; Watanabe, Hiroshi; Kuroki, Tomohiro; Nakanishi, Haruyuki; Orikasa, Yuki; Uchimoto, Yoshiharu; Takano, Hiroshi; Ohguri, Nobuaki; Matsuda, Motofumi; Murota, Tadatoshi; Uosaki, Kohei; Ueda, Wataru

    2013-07-31

    For the development of a rechargeable metal-air battery, which is expected to become one of the most widely used batteries in the future, slow kinetics of discharging and charging reactions at the air electrode, i.e., oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), respectively, are the most critical problems. Here we report that Ruddlesden-Popper-type layered perovskite, RP-LaSr3Fe3O10 (n = 3), functions as a reversible air electrode catalyst for both ORR and OER at an equilibrium potential of 1.23 V with almost no overpotentials. The function of RP-LaSr3Fe3O10 as an ORR catalyst was confirmed by using an alkaline fuel cell composed of Pd/LaSr3Fe3O10-2x(OH)2x·H2O/RP-LaSr3Fe3O10 as an open circuit voltage (OCV) of 1.23 V was obtained. RP-LaSr3Fe3O10 also catalyzed OER at an equilibrium potential of 1.23 V with almost no overpotentials. Reversible ORR and OER are achieved because of the easily removable oxygen present in RP-LaSr3Fe3O10. Thus, RP-LaSr3Fe3O10 minimizes efficiency losses caused by reactions during charging and discharging at the air electrode and can be considered to be the ORR/OER electrocatalyst for rechargeable metal-air batteries.

  10. The activity of nanocrystalline Fe-based alloys as electrode materials for the hydrogen evolution reaction

    NASA Astrophysics Data System (ADS)

    Müller, Christian Immanuel; Sellschopp, Kai; Tegel, Marcus; Rauscher, Thomas; Kieback, Bernd; Röntzsch, Lars

    2016-02-01

    In view of alkaline water electrolysis, the activities for the hydrogen evolution reaction of nanocrystalline Fe-based electrode materials were investigated and compared with the activities of polycrystalline Fe and Ni. Electrochemical methods were used to elucidate the overpotential value, the charge transfer resistance and the double layer capacity. Structural properties of the electrode surface were determined with SEM, XRD and XPS analyses. Thus, a correlation between electrochemical and structural parameters was found. In this context, we report on a cyclic voltammetric activation procedure which causes a significant increase of the surface area of Fe-based electrodes leading to a boost in effective activity of the activated electrodes. It was found that the intrinsic activity of activated Fe-based electrodes is very high due to the formation of a nanocrystalline surface layer. In contrast, the activation procedure influences only the intrinsic activity of the Ni electrodes without the formation of a porous surface layer.

  11. Assemblies of protective anion exchange membrane on air electrode for its efficient operation in aqueous alkaline electrolyte

    NASA Astrophysics Data System (ADS)

    Bertolotti, Bruno; Chikh, Linda; Vancaeyzeele, Cédric; Alfonsi, Séverine; Fichet, Odile

    2015-01-01

    Aqueous alkaline metal-air batteries represent promising energy storage devices when supplied with atmospheric air. However, under this condition, the air electrode shows a very short life time (i.e. 50 h of operation in 5 M LiOH at -10 mA cm-2), mainly due to the precipitation of carbonates inside the electrode porosity. The air electrode can then be protected by an anion exchange membrane on the electrolyte side. In this paper, we demonstrate that the efficiency of this protective membrane depends on the assembly method on the electrode. When a modified poly(epichlorohydrin) (PECH) network is synthesized directly on the electrode, the polymer seeps inside the electrode porosity, and a suitable interface inducing negligible additional polarization in comparison with classical pressure-assembled membranes is obtained. This protected electrode shows improved stability of up to 160 h of operation in 5 M LiOH. This performance is improved to 350 h by adjusting the conductivity and the ionic exchange capacity. Finally, the interest of interpenetrating polymer network (IPN) architecture compared to a single network is confirmed. Indeed, an electrode protected with a PECH/poly(2-hydroxyethyl methacrylate) (PHEMA) IPN is stable for 650 h in 5 M LiOH. In addition, degradation process becomes reversible since the assembly can be regenerated, which is not possible for the bare electrode.

  12. A comparison of retinal prosthesis electrode array substrate materials.

    PubMed

    Weiland, James D; Humayun, Mark S; Eckhardt, Helmut; Ufer, Stefan; Laude, Lucien; Basinger, Brooke; Tai, Yu-Chong

    2009-01-01

    Simulations of artificial vision suggest that 1000 electrodes may be required to restore vision to individuals with diseases of the outer retina. In order to achieve such an implant, new technology is needed, since the state-of-the-art implantable neural stimulator has at most 22 contacts with neural tissue. A critical component of this system is the multi-channel, stimulating electrode array. This array must meet very challenging, competing requirements for manufacturing, integration, surgical handling, and biocompatibility. Our lab has evaluated 3 polymers as retinal prosthesis substrates: polyimide, parylene, and silicone.

  13. Electrode

    SciTech Connect

    Clere, T.M.

    1983-08-30

    A 3-dimensional electrode is disclosed having substantially coplanar and substantially flat portions and ribbon-like curved portions, said curved portions being symmetrical and alternating in rows above and below said substantially coplanar, substantially flat portions, respectively, and a geometric configuration presenting in one sectional aspect the appearance of a series of ribbon-like oblate spheroids interrupted by said flat portions and in another sectional aspect, 90/sup 0/ from said one aspect, the appearance of a square wave pattern.

  14. Gas diffusion-type oxygen electrode using perovskite-type oxides for metal-air batteries

    SciTech Connect

    Hyodo, Takeo; Miura, Norio; Yamazoe, Noboru

    1995-12-31

    In order to develop an air cathode of metal-air batteries, oxygen reduction behavior of gas diffusion-type carbon electrodes loaded with perovskite-type oxides, La{sub 1{minus}x}A{prime}{sub x}FeO{sub 3} (A{prime} = Ca, Sr, Ba, 0 {le} x {le} 1.0), was examined in 8 M KOH at 60 C. Among the oxide catalysts tested, La{sub 0.5}Sr{sub 0.5}FeO{sub 3} (specific surface area: 21.5 m{sup 2}{center_dot}g{sup {minus}1}) gave the highest electrode performance. On the basis of electrode reaction kinetics, H{sub 2}O{sub 2} decomposition rates, and temperature programmed desorption of oxygen, it was concluded that such a performance was attributable to the active sites of the oxide for the direct 4-electron reduction of oxygen. Moreover, the electrode using La{sub 0.5}Sr{sub 0.5}FeO{sub 3} was found to be rather stable in a short-term operation for 90 h at 300 mA{center_dot}cm{sup {minus}2}.

  15. High voltage, rechargeable lithium batteries using newly-developed carbon for negative electrode material

    NASA Astrophysics Data System (ADS)

    Yamaura, Junichi; Ozaki, Yoshiyuki; Morita, Akiyoshi; Ohta, Akira

    1993-03-01

    Carbon is a good candidate for negative electrodes because it can take the form of lithium intercalation compounds. We discussed the characteristics of typical carbon materials which have been studied as negative electrode materials. We have found that the mesophase pitch-based carbon microbead (MCMB) of high graphitization stage which have been graphitized at a high temperature such as 2800 C gives good characteristics as a negative electrode for rechargeable lithium batteries. The cylindrical 'AA-size' batteries of our trial products using LiCoO2 as the positive electrode and the M CMB graphitized at 2800 C as the negative electrode have been found to provide large capacities of 500 mA h and high voltages of 3.7 V with high energy densities of 240 W h/l, 100 W h/kg.

  16. Electrochemical degradation of trichloroacetic acid in aqueous media: influence of the electrode material.

    PubMed

    Esclapez, M D; Díez-García, M I; Sàez, V; Bonete, P; González-García, José

    2013-01-01

    The electrochemical degradation of trichloroacetic acid (TCAA) in water has been analysed through voltammetric studies with a rotating disc electrode and controlled-potential bulk electrolyses. The influence of the mass-transport conditions and initial concentration of TCAA for titanium, stainless steel and carbon electrodes has been studied. It is shown that the electrochemical reduction of TCAA takes place prior to the massive hydrogen evolution in the potential window for all electrode materials studied. The current efficiency is high (> 18%) compared with those normally reported in the literature, and the fractional conversion is above 50% for all the electrodes studied. Only dichloroacetic acid (DCAA) and chloride anions were routinely detected as reduction products for any of the electrodes, and reasonable values of mass balance error were obtained. Of the three materials studied, the titanium cathode gave the best results.

  17. Method for producing electrodes using microscale or nanoscale materials obtained from hydrogendriven metallurgical reactions

    DOEpatents

    Reilly, James J.; Adzic, Gordana D.; Johnson, John R.; Vogt, Thomas; McBreen, James

    2003-09-02

    A method is provided for producing electrodes using microscale and nanoscale metal materials formed from hydrogen driven metallurgical processes; such a the HD (hydriding, dehydriding) process, the HDDR (hydriding, dehydriding, disproportionation, and recombination) process, and variants thereof.

  18. Thin film lithium-based batteries and electrochromic devices fabricated with nanocomposite electrode materials

    DOEpatents

    Gillaspie, Dane T; Lee, Se-Hee; Tracy, C. Edwin; Pitts, John Roland

    2014-02-04

    Thin-film lithium-based batteries and electrochromic devices (10) are fabricated with positive electrodes (12) comprising a nanocomposite material composed of lithiated metal oxide nanoparticles (40) dispersed in a matrix composed of lithium tungsten oxide.

  19. Engineering hybrid nanostructures of active materials: Applications as electrode materials in lithium ion rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Huang, Huan

    Aiming to significantly improve the electrochemical properties of electroactive materials for lithium ion batteries, three novel hybrid nanostructures were developed in this thesis. These include nanostructure A: V2O 5 coated on polymer electrolyte-grafted carbon black, nanostructure B: electrode materials incorporated into an electronically conductive carbon web, and nanostructure C: electrode materials dispersed in a conductive porous carbon matrix. Nanocomposites possessing nanostructure A are fast electronic and ionic transport materials. The improved kinetic properties are due to the incorporated carbon core and the grafted polymer electrolyte in the unique structure. The V2O5 xerogel coated polymer electrolyte-grafted carbon blacks, or V2O5/C-PEG, can reach a capacity as high as 320 mAh/g, and exhibit outstanding rate sustainability (e.g. 190 mAh/g at 14C). This class of nanostructured composites is promising for high power/current applications. Nanostructure B was extremely successful when applied to very poorly conductive active materials, such as LiFePO4 and Li3V 2(PO4)3. In this nanostructure, the web-like carbon framework not only supplies a facile electron transport path, but also provides excellent electronic contact between carbon and the insulating active materials. At room temperature, the LiFePO4/C nanocomposite successfully reaches almost full capacity, along with greatly improved rate sustainability and excellent cycling stability. At elevated temperatures (e.g. 40°C and 60°C), the full capacity is readily accessible over a wide rate range, even at a very fast rate of 2C or 5C. The Li3V2(PO4) 3/C nanocomposite can extract all three lithium in the formula at a rate of 1C, resulting in a high capacity of 200 mAh/g. Therefore, through designing hybrid nanostructures with nanostructure B, we can make insulating active materials into good cathode materials. Nanostructure C was employed for Sn-based anode materials, in order to improve their cycling

  20. Direct laser immobilization of photosynthetic material on screen printed electrodes for amperometric biosensor

    SciTech Connect

    Boutopoulos, Christos; Zergioti, Ioanna; Touloupakis, Eleftherios; Pezzotti, Ittalo; Giardi, Maria Teresa

    2011-02-28

    This letter demonstrates the direct laser printing of photosynthetic material onto low cost nonfunctionalized screen printed electrodes for the fabrication of photosynthesis-based amperometric biosensors. The high kinetic energy of the transferred material induces direct immobilization of the thylakoids onto the electrodes without the use of linkers. This type of immobilization is able to establish efficient electrochemical contact between proteins and electrode, stabilizing the photosynthetic biomolecule and transporting electrons to the solid state device with high efficiency. The functionality of the laser printed biosensors was evaluated by the detection of a common herbicide such as Linuron.

  1. Calcium manganite as oxygen electrode materials for reversible solid oxide fuel cell.

    PubMed

    Ni, Chengsheng; Irvine, John T S

    2015-01-01

    For an efficient high-temperature reversible solid oxide fuel cell (RSOFC), the oxygen electrode should be highly active for the conversion between oxygen anions and oxygen gas. CaMnO(3-δ) (CM) is a perovskite that can be readily reduced with the formation of Mn(3+) giving rise to oxygen defective phases. CM is examined here as the oxygen electrode for a RSOFC. CaMn(0.9)Nb(0.1)O(3-δ) (CMN) with Nb doping shows superior electric conductivity (125 S cm(-1) at 700 °C) compared with CM (1-5 S cm(-1) at 700 °C) in air which is also examined for comparison. X-ray diffraction (XRD) data show that CM and CMN are compatible with the widely used yttria-stabilized zirconia (YSZ) electrolyte up to 950 °C. Both materials show a thermal expansion coefficient (TEC) close to 10.8-10.9 ppm K(-1) in the temperature range between 100-750 °C, compatible with that of YSZ. Polarization curves and electrochemical impedance spectra for both fuel cell and steam electrolysis modes were investigated at 700 °C, showing that CM presented a polarization resistance of 0.059 Ω cm(2) under a cathodic bias of -0.4 V while CMN gave a polarization resistance of 0.081 Ω cm(2) under an anodic bias of 0.4 V. The phase stability up to 900 °C of these materials was investigated with thermogravimetric analysis (TGA) and variable temperature XRD.

  2. Optoelectric patterning: Effect of electrode material and thickness on laser-induced AC electrothermal flow.

    PubMed

    Mishra, Avanish; Khor, Jian-Wei; Clayton, Katherine N; Williams, Stuart J; Pan, Xudong; Kinzer-Ursem, Tamara; Wereley, Steve

    2016-02-01

    Rapid electrokinetic patterning (REP) is an emerging optoelectric technique that takes advantage of laser-induced AC electrothermal flow and particle-electrode interactions to trap and translate particles. The electrothermal flow in REP is driven by the temperature rise induced by the laser absorption in the thin electrode layer. In previous REP applications 350-700 nm indium tin oxide (ITO) layers have been used as electrodes. In this study, we show that ITO is an inefficient electrode choice as more than 92% of the irradiated laser on the ITO electrodes is transmitted without absorption. Using theoretical, computational, and experimental approaches, we demonstrate that for a given laser power the temperature rise is controlled by both the electrode material and its thickness. A 25-nm thick Ti electrode creates an electrothermal flow of the same speed as a 700-nm thick ITO electrode while requiring only 14% of the laser power used by ITO. These results represent an important step in the design of low-cost portable REP systems by lowering the material cost and power consumption of the system.

  3. Air electrode material for high temperature electrochemical cells

    DOEpatents

    Ruka, Roswell J.

    1985-01-01

    Disclosed is a solid solution with a perovskite-like crystal structure having the general formula La.sub.1-x-w (M.sub.L).sub.x (Ce).sub.w (M.sub.S1).sub.1-y (M.sub.S2).sub.y O.sub.3 where M.sub.L is Ca, Sr, Ba, or mixtures thereof, M.sub.S1 is Mn, Cr, or mixtures thereof and M.sub.S2 is Ni, Fe, Co, Ti, Al, In, Sn, Mg, Y, Nb, Ta, or mixtures thereof, w is about 0.05 to about 0.25, x+w is about 0.1 to about 0.7, and y is 0 to about 0.5. In the formula, M.sub.L is preferably Ca, w is preferably 0.1 to 0.2, x+w is preferably 0.4 to 0.7, and y is preferably 0. The solid solution can be used in an electrochemical cell where it more closely matches the thermal expansion characteristics of the support tube and electrolyte of the cell.

  4. Characterization of solid electrode materials using chronoamperometry: A study of the alkaline γ-MnO 2 electrode

    NASA Astrophysics Data System (ADS)

    Malloy, Aaron P.; Donne, Scott W.

    Large voltage step chronoamperometry is shown to be a time-efficient means to examine solid electrode materials compared with conventional electrochemical methods such as linear sweep voltammetry (LSV) and step potential electrochemical spectroscopy (SPECS), all the while providing comparable information concerning the rate capability of a material and its capacity. The applicability of the technique is demonstrated through a study of the alkaline γ-MnO 2 electrode. By sampling the current (and hence the charge) at various times after the chronoamperometric voltage step, the compatibility between chronoamperometry and LSV is disclosed. Furthermore, modelling of the chronoamperometric data using two curves based on a spherical diffusion model representing fast and slow discharge processes are found to be statistically suitable. From this modelling, values of A√ D (where A is the electrochemically active surface area and D is the diffusion coefficient) for the two processes are 3.89 × 10 -4 and 0.70 × 10 -4 cm 3 s -1/2 g -1, respectively, both of which are comparable with A√ D data extracted from a SPECS experiment on an identical electrode.

  5. Compliant Electrode and Composite Material for Piezoelectric Wind and Mechanical Energy Conversions

    NASA Technical Reports Server (NTRS)

    Chen, Bin (Inventor)

    2015-01-01

    A thin film device for harvesting energy from wind. The thin film device includes one or more layers of a compliant piezoelectric material formed from a composite of a polymer and an inorganic material, such as a ceramic. Electrodes are disposed on a first side and a second side of the piezoelectric material. The electrodes are formed from a compliant material, such as carbon nanotubes or graphene. The thin film device exhibits improved resistance to structural fatigue upon application of large strains and repeated cyclic loadings.

  6. A Metal-Free, Free-Standing, Macroporous Graphene@g-C₃N₄ Composite Air Electrode for High-Energy Lithium Oxygen Batteries.

    PubMed

    Luo, Wen-Bin; Chou, Shu-Lei; Wang, Jia-Zhao; Zhai, Yu-Chun; Liu, Hua-Kun

    2015-06-01

    The nonaqueous lithium oxygen battery is a promising candidate as a next-generation energy storage system because of its potentially high energy density (up to 2-3 kW kg(-1)), exceeding that of any other existing energy storage system for storing sustainable and clean energy to reduce greenhouse gas emissions and the consumption of nonrenewable fossil fuels. To achieve high energy density, long cycling stability, and low cost, the air electrode structure and the electrocatalysts play important roles. Here, a metal-free, free-standing macroporous graphene@graphitic carbon nitride (g-C3N4) composite air cathode is first reported, in which the g-C3N4 nanosheets can act as efficient electrocatalysts, and the macroporous graphene nanosheets can provide space for Li2O2 to deposit and also promote the electron transfer. The electrochemical results on the graphene@g-C3N4 composite air electrode show a 0.48 V lower charging plateau and a 0.13 V higher discharging plateau than those of pure graphene air electrode, with a discharge capacity of nearly 17300 mA h g(-1)(composite) . Excellent cycling performance, with terminal voltage higher than 2.4 V after 105 cycles at 1000 mA h g(-1)(composite) capacity, can also be achieved. Therefore, this hybrid material is a promising candidate for use as a high energy, long-cycle-life, and low-cost cathode material for lithium oxygen batteries.

  7. Effect of Different Electrode Materials on the Electropolymerization Process of Aniline in Nitric Acid Media

    NASA Astrophysics Data System (ADS)

    Li, Yaozong; Yi, Yun; Yang, Weifang; Liu, Xiaoqing; Li, Yuanyuan; Wang, Wei

    2017-02-01

    The electropolymerization process of aniline on different electrode surfaces such as Pt, Au, RuTi and polyaniline film in nitric acid solution containing 1 M aniline was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Proposed electrical equivalent circuits were used to give a further analysis. Results show that the electrode materials accelerate the aniline electropolymerization remarkably as a catalyst, especially the electrochemical oxidation process of monomer aniline to its cation radical, which is the key step to incur the electropolymerization reaction of aniline on the electrode surface. The polymerization of aniline on RuTi electrode has the lowest reaction resistance for its adsorption sites, and the catalytic effects of these different electrodes decrease in the order: RuTi > polyaniline film > Pt > Au. The results also show that several states of polyaniline films are formed during the potential linear scan process in nitric acid solution and the corresponding oxidation and reduction reaction are reversible.

  8. Porous hollow carbon spheres for electrode material of supercapacitors and support material of dendritic Pt electrocatalyst

    NASA Astrophysics Data System (ADS)

    Fan, Yang; Liu, Pei-Fang; Huang, Zhong-Yuan; Jiang, Tong-Wu; Yao, Kai-Li; Han, Ran

    2015-04-01

    Porous hollow carbon spheres (PHCSs) are prepared through hydrothermal carbonization of alginic acid and subsequent chemical activation by KOH. The porosity of the alginic acid derived PHCSs can be finely modulated by varying activation temperature in the range of 600-900 °C. The PHCSs activated at 900 °C possess the largest specific surface area (2421 m2 g-1), well-balanced micro- and mesoporosity, as well as high content of oxygen-containing functional groups. As the electrode material for supercapacitors, the PHCSs exhibit superior capacitive performance with specific capacitance of 314 F g-1 at current density of 1 A g-1. Pt nanodendrites supported on the PHCSs are synthesized by polyol reduction method which exhibit high electrocatalytic activity towards methanol oxidation reaction (MOR). Moreover, CO-poisoning tolerance of the Pt nanodendrites is greatly enhanced owing to the surface chemical property of the PHCSs support.

  9. Effect of electrode material and design on sensitivity and selectivity for high temperature impedancemetric NOx sensors

    SciTech Connect

    Woo, L Y; Glass, R S; Novak, R F; Visser, J H

    2009-09-23

    Solid-state electrochemical sensors using two different sensing electrode compositions, gold and strontium-doped lanthanum manganite (LSM), were evaluated for gas phase sensing of NO{sub x} (NO and NO{sub 2}) using an impedance-metric technique. An asymmetric cell design utilizing porous YSZ electrolyte exposed both electrodes to the test gas (i.e., no reference gas). Sensitivity to less than 5 ppm NO and response/recovery times (10-90%) less than 10 s were demonstrated. Using an LSM sensing electrode, virtual identical sensitivity towards NO and NO{sub 2} was obtained, indicating that the equilibrium gas concentration was measured by the sensing electrode. In contrast, for cells employing a gold sensing electrode the NO{sub x} sensitivity varied depending on the cell design: increasing the amount of porous YSZ electrolyte on the sensor surface produced higher NO{sub 2} sensitivity compared to NO. In order to achieve comparable sensitivity for both NO and NO{sub 2}, the cell with the LSM sensing electrode required operation at a lower temperature (575 C) than the cell with the gold sensing electrode (650 C). The role of surface reactions are proposed to explain the differences in NO and NO{sub 2} selectivity using the two different electrode materials.

  10. Evaluation of electrode materials for all-copper hybrid flow batteries

    NASA Astrophysics Data System (ADS)

    Leung, Puiki; Palma, Jesus; Garcia-Quismondo, Enrique; Sanz, Laura; Mohamed, M. R.; Anderson, Marc

    2016-04-01

    This work evaluates a number of two- and three-dimensional electrodes for the reactions of an all-copper hybrid flow battery. Half- and full-cell experiments are conducted by minimizing the crossover effect of the copper(II) species. The battery incorporates a Nafion® cation exchange membrane and the negative electrolyte is maintained at the monovalent (colourless) state by the incorporating copper turnings in the electrolyte reservoir. Under such conditions, the half-cell coulombic efficiencies of the negative electrode reactions are all higher than 90% regardless of electrode materials and the state-of-charge (SOC). With charge-discharge cycling the half-cell from a 0% SOC, the coulombic efficiencies of the positive electrode reactions are lower than 76% with the planar carbon electrode, which further decrease in shorter charge-discharge cycles. Polarization and half-cell charge-discharge experiments suggest that the high-surface-area electrodes effectively reduce the overpotentials and improve the coulombic efficiencies of both electrode reactions. When copper fibres and carbon felt are used as the negative and positive electrodes, the average coulombic and voltage efficiencies of an all-copper flow battery are as high as c.a. 99% and c.a. 60% at 50 mA cm-2 for 35 cycles.

  11. Studies on the oxygen reduction catalyst for zinc-air battery electrode

    NASA Astrophysics Data System (ADS)

    Wang, Xianyou; Sebastian, P. J.; Smit, Mascha A.; Yang, Hongping; Gamboa, S. A.

    In this paper, perovskite type La 0.6Ca 0.4CoO 3 as a catalyst of oxygen reduction was prepared, and the structure and performance of the catalysts was examined by means of IR, X-ray diffraction (XRD), and thermogravimetric (TG). Mixed catalysts doped, some metal oxides were put also used. The cathodic polarization curves for oxygen reduction on various catalytic electrodes were measured by linear sweep voltammetry (LSV). A Zn-air battery was made with various catalysts for oxygen reduction, and the performance of the battery was measured with a BS-9300SM rechargeable battery charge/discharge device. The results showed that the perovskite type catalyst (La 0.6Ca 0.4CoO 3) doped with metal oxide is an excellent catalyst for the zinc-air battery, and can effectively stimulate the reduction of oxygen and improve the properties of zinc-air batteries, such as discharge capacity, etc.

  12. Understanding the influence of the electrode material on microbial fuel cell performance

    NASA Astrophysics Data System (ADS)

    Sanchez, David V. P.

    In this thesis, I deploy sets of electrodes into microbial fuel cells (MFC), characterize their performance, and evaluate the influence of both platinum catalysts and carbon-based electrodes on current production. The platinum work centers on improving current production by optimizing the use of the catalyst using nano-fabrication techniques. The carbon-electrode work seeks to determine the influence of the bare electrode on biofilm-anode current production. The development of electrodes for MFCs has boomed over the past decade, however, experiments aimed at identifying how catalyst deposition methods and electrode properties influence current production have been limited. The research conducted here is an attempt to expand this knowledge base for platinum catalysts and carbon electrodes. In the initial chapters (4 and 5), I discuss our attempt to decrease catalyst loadings while increasing current production through the use of platinum nanoparticles. The results demonstrate that incorporating platinum nanoparticles throughout the anode and cathode is an efficient means of increasing MFC current production relative to surface deposition because it increases catalyst surface area. The later chapters (chapters 6 and 7) develop an understanding of the importance of electrode properties (i.e. surface area, activation resistance, conductivity, surface morphology) by electrochemically evaluating well-studied anode-respiring pure cultures on different carbon electrode architectures. Two different architectures are produced by using tubular and platelet shaped constituent materials (i.e. carbon fibers and graphene nanoplatelets) and the morphologies of the electrodes are varied by altering the size of the constituent material. The electrodes are characterized and evaluated in MFCs using either Shewanella oneidensis MR-1 or Geobacter sulfurreducens as the innoculant because their bioelectrochemical physiologies are the most documented in the literature. Using the

  13. Effect of the electrode material on the breakdown voltage and space charge distribution of propylene carbonate under impulse voltage

    NASA Astrophysics Data System (ADS)

    Yang, Qing; Jin, Yang; Sima, Wenxia; Liu, Mengna

    2016-04-01

    This paper reports three types of electrode materials (copper, aluminum, and stainless steel) that are used to measure the impulse breakdown voltage of propylene carbonate. The breakdown voltage of propylene carbonate with these electrode materials is different and is in decreasing order of stainless steel, copper, and aluminum. To explore how the electrode material affects the insulating properties of the liquid dielectric, the electric field distribution and space charge distribution of propylene carbonate under impulse voltage with the three electrode materials are measured on the basis of a Kerr electro-optic test. The space charge injection ability is highest for aluminum, followed by copper, and then the stainless steel electrodes. Furthermore, the electric field distortion rate decreased in the order of the aluminum, copper, and then the stainless steel electrode. This paper explains that the difference in the electric field distortion rate between the three electrode materials led to the difference in the impulse breakdown voltage of propylene carbonate.

  14. Recent progress in nickel based materials for high performance pseudocapacitor electrodes

    NASA Astrophysics Data System (ADS)

    Feng, Liangdong; Zhu, Yufu; Ding, Hongyan; Ni, Chaoying

    2014-12-01

    Nickel based materials have been intensively investigated and considered as good potential electrode materials for pseudocapacitors due to their high theoretical specific capacity values, high chemical and thermal stability, ready availability, environmentally benign nature and lower cost. This review firstly examines recent progress in nickel oxides or nickel hydroxides for high performance pseudocapacitor electrodes. The advances of hybrid electrodes are then assessed to include hybrid systems of nickel based materials with compounds such as carbonaceous materials, metal and transition metal oxides or hydroxides, in which various strategies have been adopted to improve the electrical conductivity of nickel oxides or hydroxides. Furthermore, the energy density and power density of some recently reported NiO, nickel based composites and NiCo2O4 are summarized and discussed. Finally, we provide some perspectives as to the future directions of this intriguing field.

  15. High-capacity electrode materials for electrochemical energy storage: Role of nanoscale effects

    DOE PAGES

    Nanda, Jagjit; Martha, Surendra K.; Kalyanaraman, Ramki

    2015-06-02

    In this review, we summarize the current state-of-the art electrode materials used for high-capacity lithium-ion-based batteries and their significant role towards revolutionizing the electrochemical energy storage landscape in the area of consumer electronics, transportation and grid storage application. We discuss the role of nanoscale effects on the electrochemical performance of high-capacity battery electrode materials. Decrease in the particle size of the primary electrode materials from micron to nanometre size improves the ionic and electronic diffusion rates significantly. Nanometre-thick solid electrolyte (such as lithium phosphorous oxynitride) and oxides (such as Al2O3, ZnO, TiO2 etc.) material coatings also improve the interfacial stabilitymore » and rate capability of a number of battery chemistries. Finally, we elucidate these effects in terms of different high-capacity battery chemistries based on intercalation and conversion mechanism.« less

  16. High-capacity electrode materials for electrochemical energy storage: Role of nanoscale effects

    SciTech Connect

    Nanda, Jagjit; Martha, Surendra K.; Kalyanaraman, Ramki

    2015-06-02

    In this review, we summarize the current state-of-the art electrode materials used for high-capacity lithium-ion-based batteries and their significant role towards revolutionizing the electrochemical energy storage landscape in the area of consumer electronics, transportation and grid storage application. We discuss the role of nanoscale effects on the electrochemical performance of high-capacity battery electrode materials. Decrease in the particle size of the primary electrode materials from micron to nanometre size improves the ionic and electronic diffusion rates significantly. Nanometre-thick solid electrolyte (such as lithium phosphorous oxynitride) and oxides (such as Al2O3, ZnO, TiO2 etc.) material coatings also improve the interfacial stability and rate capability of a number of battery chemistries. Finally, we elucidate these effects in terms of different high-capacity battery chemistries based on intercalation and conversion mechanism.

  17. Making Li-air batteries rechargeable: material challenges

    SciTech Connect

    Shao, Yuyan; Ding, Fei; Xiao, Jie; Zhang, Jian; Xu, Wu; Park, Seh Kyu; Zhang, Jiguang; Wang, Yong; Liu, Jun

    2013-02-25

    A Li-air battery could potentially provide three to five times higher energy density/specific energy than conventional batteries, thus enable the driving range of an electric vehicle comparable to a gasoline vehicle. However, making Li-air batteries rechargeable presents significant challenges, mostly related with materials. Herein, we discuss the key factors that influence the rechargeability of Li-air batteries with a focus on nonaqueous system. The status and materials challenges for nonaqueous rechargeable Li-air batteries are reviewed. These include electrolytes, cathode (electocatalysts), lithium metal anodes, and oxygen-selective membranes (oxygen supply from air). The perspective of rechargeable Li-air batteries is provided.

  18. Enhanced control of electrochemical response in metallic materials in neural stimulation electrode applications

    SciTech Connect

    Watkins, K.G.; Steen, W.M.; Manna, I.

    1996-12-31

    New means have been investigated for the production of electrode devices (stimulation electrodes) which could be implanted in the human body in order to control pain, activate paralysed limbs or provide electrode arrays for cochlear implants for the deaf or for the relief of tinitus. To achieve this ion implantation and laser materials processing techniques were employed. Ir was ion implanted in Ti-6Al-4V alloy and the surface subsequently enriched in the noble metal by dissolution in sulphuric acid. For laser materials processing techniques, investigation has been carried out on the laser cladding and laser alloying of Ir in Ti wire. A particular aim has been the determination of conditions required for the formation of a two phase Ir, Ir-rich, and Ti-rich microstructure which would enable subsequent removal of the non-noble phase to leave a highly porous noble metal with large real surface area and hence improved charge carrying capacity compared with conventional non porous electrodes. Evaluation of the materials produced has been carried out using repetitive cyclic voltammetry, amongst other techniques. For laser alloyed Ir on Ti wire, it has been found that differences in the melting point and density of the materials makes control of the cladding or alloying process difficult. Investigation of laser process parameters for the control of alloying and cladding in this system was carried out and a set of conditions for the successful production of two phase Ir-rich and Ti-rich components in a coating layer with strong metallurgical bonding to the Ti alloy substrate was derived. The laser processed material displays excellent potential for further development in providing stimulation electrodes with the current carrying capacity of Ir but in a form which is malleable and hence capable of formation into smaller electrodes with improved spatial resolution compared with presently employed electrodes.

  19. Materials for suspension (semi-solid) electrodes for energy and water technologies.

    PubMed

    Hatzell, Kelsey B; Boota, Muhammad; Gogotsi, Yury

    2015-12-07

    Suspension or semi-solid electrodes have recently gained increased attention for large-scale applications such as grid energy storage, capacitive water deionization, and wastewater treatment. A suspension electrode is a multiphase material system comprised of an active (charge storing) material suspended in ionic solution (electrolyte). Gravimetrically, the electrolyte is the majority component and aids in physical transport of the active material. This principle enables, for the first time, scalability of electrochemical energy storage devices (supercapacitors and batteries) previously limited to small and medium scale applications. This critical review describes the ongoing material challenges encompassing suspension-based systems. The research described here combines classical aspects of electrochemistry, colloidal science, material science, fluid mechanics, and rheology to describe ion and charge percolation, adsorption of ions, and redox charge storage processes in suspension electrodes. This review summarizes the growing inventory of material systems, methods and practices used to characterize suspension electrodes, and describes universal material system properties (rheological, electrical, and electrochemical) that are pivotal in the design of high performing systems. A discussion of the primary challenges and future research directions is included.

  20. Materials for suspension (semi-solid) electrodes for energy and water technologies

    SciTech Connect

    Hatzell, Kelsey B.; Boota, Muhammad; Gogotsi, Yury

    2015-01-01

    Suspension or semi-solid electrodes have recently gained increased attention for large-scale applications such as grid energy storage, capacitive water deionization, and wastewater treatment. A suspension electrode is a multiphase material system comprised of an active (charge storing) material suspended in ionic solution (electrolyte). Gravimetrically, the electrolyte is the majority component and aids in physical transport of the active material. For the first time, this principle enables, scalability of electrochemical energy storage devices (supercapacitors and batteries) previously limited to small and medium scale applications. This critical review describes the ongoing material challenges encompassing suspension-based systems. The research described here combines classical aspects of electrochemistry, colloidal science, material science, fluid mechanics, and rheology to describe ion and charge percolation, adsorption of ions, and redox charge storage processes in suspension electrodes. Our review summarizes the growing inventory of material systems, methods and practices used to characterize suspension electrodes, and describes universal material system properties (rheological, electrical, and electrochemical) that are pivotal in the design of high performing systems. We include a discussion of the primary challenges and future research directions.

  1. LDHs as electrode materials for electrochemical detection and energy storage: supercapacitor, battery and (bio)-sensor.

    PubMed

    Mousty, Christine; Leroux, Fabrice

    2012-11-01

    From an exhaustive overview based on applicative academic literature and patent domain, the relevance of Layered Double Hydroxide (LDHs) as electrode materials for electrochemical detection of organic molecules having environmental or health impact and energy storage is evaluated. Specifically the focus is driven on their application as supercapacitor, alkaline or lithium battery and (bio)-sensor. Inherent to the high versatility of their chemical composition, charge density, anion exchange capability, LDH-based materials are extensively studied and their performances for such applications are reported. Indeed the analytical characteristics (sensitivity and detection limit) of LDH-based electrodes are scrutinized, and their specific capacity or capacitance as electrode battery or supercapacitor materials, are detailed.

  2. Electrical characterization of conductive textile materials and its evaluation as electrodes for venous occlusion plethysmography.

    PubMed

    Goy, C B; Dominguez, J M; Gómez López, M A; Madrid, R E; Herrera, M C

    2013-08-01

    The ambulatory monitoring of biosignals involves the use of sensors, electrodes, actuators, processing tools and wireless communication modules. When a garment includes these elements with the purpose of recording vital signs and responding to specific situations it is call a 'Smart Wearable System'. Over the last years several authors have suggested that conductive textile material (e-textiles) could perform as electrode for these systems. This work aims at implementing an electrical characterization of e-textiles and an evaluation of their ability to act as textile electrodes for lower extremity venous occlusion plethysmography (LEVOP). The e-textile electrical characterization is carried out using two experimental set-ups (in vitro evaluation). Besides, LEVOP records are obtained from healthy volunteers (in vivo evaluation). Standard Ag/AgCl electrodes are used for comparison in all tests. Results shown that the proposed e-textiles are suitable for LEVOP recording and a good agreement between evaluations (in vivo and in vitro) is found.

  3. Combination of a novel electrode material and artificial mediators to enhance power generation in an MFC.

    PubMed

    Taskan, Ergin; Ozkaya, Bestamin; Hasar, Halil

    2015-01-01

    This study focuses on two main aspects: developing a novel cost-effective electrode material and power production from domestic wastewater using three different mediators. Methylene blue (MB), neutral red (NR) and 2-hydroxy-1,4-naphthoquinone (HNQ) were selected as electrode mediators with different concentrations. A tin-coated copper mesh electrode was tested as anode electrode. Maximum power density of the microbial fuel cell (MFC) with 300 μM MB was 636 mW/m². Optimal mediator concentrations with respect to the achieved maximum power output for MB, NR and HNQ were 300 μM, 200 μM and 50 μM, respectively. The results demonstrate that tin-coated copper mesh showed a higher biocompatibility and electrical conductivity.

  4. Nanostructured pseudocapacitive materials decorated 3D graphene foam electrodes for next generation supercapacitors

    NASA Astrophysics Data System (ADS)

    Patil, Umakant; Lee, Su Chan; Kulkarni, Sachin; Sohn, Ji Soo; Nam, Min Sik; Han, Suhyun; Jun, Seong Chan

    2015-04-01

    Nowadays, advancement in performance of proficient multifarious electrode materials lies conclusively at the core of research concerning energy storage devices. To accomplish superior capacitance performance the requirements of high capacity, better cyclic stability and good rate capability can be expected from integration of electrochemical double layer capacitor based carbonaceous materials (high power density) and pseudocapacitive based metal hydroxides/oxides or conducting polymers (high energy density). The envisioned three dimensional (3D) graphene foams are predominantly advantageous to extend potential applicability by offering a large active surface area and a highly conductive continuous porous network for fast charge transfer with decoration of nanosized pseudocapacitive materials. In this article, we review the latest methodologies and performance evaluation for several 3D graphene based metal oxides/hydroxides and conducting polymer electrodes with improved electrochemical properties for next-generation supercapacitors. The most recent research advancements of our and other groups in the field of 3D graphene based electrode materials for supercapacitors are discussed. To assess the studied materials fully, a careful interpretation and rigorous scrutiny of their electrochemical characteristics is essential. Auspiciously, both nano-structuration as well as confinement of metal hydroxides/oxides and conducting polymers onto a conducting porous 3D graphene matrix play a great role in improving the performance of electrodes mainly due to: (i) active material access over large surface area with fast charge transportation; (ii) synergetic effect of electric double layer and pseudocapacitive based charge storing.

  5. Study of the contributions of the electrode materials to the plasma of a high-current vacuum spark

    SciTech Connect

    Bashutin, O. A.; Vovchenko, E. D.; Dodulad, E. I.; Savjolov, A. S.; Sarantsev, S. A.

    2012-03-15

    The contribution of the electrode material to the formation of the plasma of a low-inductive high-current vacuum spark and its influence on the process of discharge micropinching were studied using X-ray spectroscopy and laser diagnostics. Electrode system configurations are determined in which the contributions of the materials of both electrodes to the plasma emitting X-rays are comparable and in which the contribution of one electrode is dominating. It is found that discharge pinching occurs primarily in the vapor of the pointed electrode independently of its polarity. The experimental results indicate the formation of a suprathermal electron beam in the micropinch region.

  6. Hydrogen peroxide detection in wet air with a Prussian Blue based solid salt bridged three electrode system.

    PubMed

    Komkova, Maria A; Karyakina, Elena E; Marken, Frank; Karyakin, Arkady A

    2013-03-05

    We report on a novel electroanalytical system for hydrogen peroxide (H2O2) detection in humidity or droplets of aerosol, formed by air bubbling through a washing chamber; the resulting flow mimics the exhaled human breath. The system is based on a planar three-electrode structure (with a Prussian Blue based H2O2 transducer modified working electrode) bridged by a solid salt-saturated filament material (filter paper, cotton textile). Respective to the hydrogen peroxide content in the washing valve, the response of the aerosol-sensing system is linear in the concentration range of 0.1-10 μM, which overlaps the generally accepted H2O2 content in exhaled breath condensate (EBC), with the sensitivity of 8 A M(-1) cm(-2). The response to the upper limit of the calibration range is stable for more than 50 injection cycles recorded within 3 days. Both the stability and the suitable calibration range allow one to consider the reported aerosol-sensing system as a prototype for a simple (avoiding intermediate EBC collection) noninvasive diagnostic tool for pulmonary patients.

  7. Pr4Ni3O10+δ: A new promising oxygen electrode material for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Vibhu, Vaibhav; Rougier, Aline; Nicollet, Clément; Flura, Aurélien; Fourcade, Sébastien; Penin, Nicolas; Grenier, Jean-Claude; Bassat, Jean-Marc

    2016-06-01

    The present work is focused on the study of Pr4Ni3O10+δ as a new cathode material for Solid Oxide Fuel Cells (SOFCs). The structural study leads to an indexation in orthorhombic structure with Fmmm space group, this structure being thermally stable throughout the temperature range up to 1000 °C under air and oxygen. The variation of oxygen content (10+δ) as a function of temperature under different atmospheres show that Pr4Ni3O10+δ is always oxygen over-stoichiometric, which further suggests its MIEC properties. The polarization resistance (Rp) of Pr4Ni3O10+δ electrode is measured for GDC/co-sintered and two-step sintered half cells. The Rp for co-sintered sample is found to be 0.16 Ω cm2 at 600 °C under air, which is as low as the one of highest performing Pr2NiO4+δ nickelate (Rp = 0.15 Ω cm2 at 600 °C). Moreover, an anode supported (Ni-YSZ//YSZ) single cell including GDC//Pr4Ni3O10+δ co-sintered electrode shows a maximum power density of 1.60 W cm-2 at 800 °C and 0.68 W cm-2 at 700 °C. Here, the work is emphasized on the very close electrochemical performance of Pr4Ni3O10+δ compared to the one of Pr2NiO4+δ with higher chemical stability, which gives great interests to consider this material as a very interesting oxygen-electrode for SOFCs.

  8. Tungsten materials as durable catalyst supports for fuel cell electrodes

    NASA Astrophysics Data System (ADS)

    Perchthaler, M.; Ossiander, T.; Juhart, V.; Mitzel, J.; Heinzl, C.; Scheu, C.; Hacker, V.

    2013-12-01

    Durable platinum catalyst support materials, e.g. tungsten carbide (WC), tungsten oxide (WOx) and self-synthesized tungsten oxide (WOxs) were evaluated for the use in High-Temperature Proton Exchange Fuel Cells (HT-PEM) based on phosphoric acid doped polybenzimidazole as electrolyte. The support materials and the catalyst loaded support materials were characterized ex-situ by cyclic voltammetry in HClO4, potential cycling, CO-stripping, electron microscopy and X-ray diffraction measurements. The tungsten oxide and tungsten carbide based supported catalysts were compared to High Surface Area Carbon (HSAC), each coated with platinum via the same in-house manufacturing procedures. The in-house manufacturing procedures resulted in catalyst particle sizes on HSAC of 3-4 nm with a uniform distribution. The in-situ Potential Cycling experiments of WOx or WOxs supported catalysts showed much lower degradation rates compared to High Surface Area Carbons. The formation of WOx species on WC was proven by ex- and in-situ cyclic voltammetric studies and thermogravimetric analyses. X-ray diffraction, ex-situ cyclic voltammetry and in-situ cyclic voltammetry showed that WOx is formed from WC as starting material under oxidizing conditions. Finally a 1000 h durability test with WOx as catalyst support material on the anode was done in a HT-PEM fuel cell with reformed methanol on the anode.

  9. Investigation of materials for inert electrodes in aluminum electrodeposition cells

    SciTech Connect

    Haggerty, J. S.; Sadoway, D. R.

    1987-09-14

    Work was divided into major efforts. The first was the growth and characterization of specimens; the second was Hall cell performance testing. Cathode and anode materials were the subject of investigation. Preparation of specimens included growth of single crystals and synthesis of ultra high purity powders. Special attention was paid to ferrites as they were considered to be the most promising anode materials. Ferrite anode corrosion rates were studied and the electrical conductivities of a set of copper-manganese ferrites were measured. Float Zone, Pendant Drop Cryolite Experiments were undertaken because unsatisfactory choices of candidate materials were being made on the basis of a flawed set of selection criteria applied to an incomplete and sometimes inaccurate data base. This experiment was then constructed to determine whether the apparatus used for float zone crystal growth could be adapted to make a variety of important based melts and their interactions with candidate inert anode materials. The third major topic was Non Consumable Anode (Data Base, Candidate Compositions), driven by our perception that the basis for prior selection of candidate materials was inadequate. Results are presented. 162 refs., 39 figs., 18 tabs.

  10. Investigation of materials for inert electrodes in aluminum electrodeposition cells

    NASA Astrophysics Data System (ADS)

    Haggerty, J. S.; Sadoway, D. R.

    1987-09-01

    Work was divided into major efforts. The first was the growth and characterization of specimens; the second was Hall cell performance testing. Cathode and anode materials were the subject of investigation. Preparation of specimens included growth of single crystals and synthesis of ultra high purity powders. Special attention was paid to ferrites as they were considered to be the most promising anode materials. Ferrite anode corrosion rates were studied and the electrical conductivities of a set of copper-manganese ferrites were measured. Float Zone, Pendant Drop Cryolite Experiments were undertaken because unsatisfactory choices of candidate materials were being made on the basis of a flawed set of selection criteria applied to an incomplete and sometimes inaccurate data base. This experiment was then constructed to determine whether the apparatus used for float zone crystal growth could be adapted to make a variety of important based melts and their interactions with candidate inert anode materials. Compositions), driven by our perception that the basis for prior selection of candidate materials was inadequate. Results are presented.

  11. High surface area electrode materials by direct metallization of porous substrates

    SciTech Connect

    Chyan, O.; Chen, J.J.; Liu, M.; Richmond, M.G.; Yang, K.

    1995-12-31

    Recent advances in high surface area (HSA) electrode materials have played an important role in the development of high-performance batteries and fuel cells. HSA electrodes can significantly increase the power-density of batteries and fuel cells by enhancing the heterogeneous electrochemical reaction rate and concurrently reducing battery and fuel cell size and weight. The compactness of HSA electrodes can also reduce the ohmic potential drop, which has the clear advantage of reducing power losses. This paper reports results on utilizing direct metallization of porous substrates to prepare new HSA electrode materials. Specifically, Nickel HSA electrode materials, relevant to the Ni-Cd and metal-hydride rechargeable batteries, were prepared on porous carbon substrates by direct thermolysis of organometallic precursors and/or electroless Ni plating. SEM and XPS characterization results indicate a Ni metallic film was conformally coated over the porous carbon skeleton. The real electroactive areas were determined electrochemically in NaOH solution and results will be discussed in correlation with the metallization conditions.

  12. Electrode material dependence of two-dimensional electron and vapour density distribution over vacuum arc discharge

    NASA Astrophysics Data System (ADS)

    Inada, Y.; Matsuoka, S.; Kumada, A.; Ikeda, H.; Hidaka, K.

    2017-03-01

    Electrode material dependence of intense-mode vacuum arc behaviour was systematically investigated by using the Shack-Hartmann method capable of simultaneously visualising two-dimensional electron and metal vapour density distributions from single-shot recordings. The electrode materials studied included Cu, CuCr (Cu75Cr25 wt. %), WC, and AgWC (Ag40WC60 wt. %). A comparison between the Cu and CuCr electrodes showed that the metal vapour densities for the CuCr decreased in an even shorter time scale than for the Cu. In the case of the WC electrodes, the widths of the electron density distributions became narrower as the arc current decreased although the electron densities hardly decreased in the decaying process of the arc current. The density measurements conducted at the late stage of the vacuum arcs demonstrated that the metal vapour densities around the anode were maintained at the highest value for the AgWC among the electrode materials in this study.

  13. Air Damping in a Fan-Shaped Rotational Resonator with Comb Electrodes

    NASA Astrophysics Data System (ADS)

    Uchida, Yuki; Sugano, Koji; Tsuchiya, Toshiyuki; Tabata, Osamu; Ikehara, Tsuyoshi

    We theoretically and experimentally evaluated the damping effect in a rotational resonator with a comb-drive actuator and sensor. The resonator was fabricated from an SOI wafer and has a fan-shaped mass. The underlying substrate was removed using back side deep reactive ion etching. One set of comb electrodes was attached to each side of the mass: one for electrostatic driving and the other for capacitive detection. In our theoretical analysis, the dynamics of the resonator were simplified so that they could be represented by a lumped system. In this lumped system, the damping coefficient was estimated by assuming the damping to be slide film damping and the air flow to be a Stokes flow. The phase shift due to the slide film damping of thick air layers was included in the lumped system. In the experimental evaluation, one side of the rotational combs was removed step-by-step and a half of the mass using a laser trimming tool so that the individual damping effects caused by the comb electrodes and mass could be determined quantitatively. We compared the experimental results with the results of the theoretical analysis and found that the difference in the damping coefficients between the experimental results and results of the theoretical analysis was less than 40%.

  14. Recent Development of Advanced Electrode Materials by Atomic Layer Deposition for Electrochemical Energy Storage

    PubMed Central

    2016-01-01

    Electrode materials play a decisive role in almost all electrochemical energy storage devices, determining their overall performance. Proper selection, design and fabrication of electrode materials have thus been regarded as one of the most critical steps in achieving high electrochemical energy storage performance. As an advanced nanotechnology for thin films and surfaces with conformal interfacial features and well controllable deposition thickness, atomic layer deposition (ALD) has been successfully developed for deposition and surface modification of electrode materials, where there are considerable issues of interfacial and surface chemistry at atomic and nanometer scale. In addition, ALD has shown great potential in construction of novel nanostructured active materials that otherwise can be hardly obtained by other processing techniques, such as those solution‐based processing and chemical vapor deposition (CVD) techniques. This review focuses on the recent development of ALD for the design and delivery of advanced electrode materials in electrochemical energy storage devices, where typical examples will be highlighted and analyzed, and the merits and challenges of ALD for applications in energy storage will also be discussed. PMID:27840793

  15. Recent Development of Advanced Electrode Materials by Atomic Layer Deposition for Electrochemical Energy Storage.

    PubMed

    Guan, Cao; Wang, John

    2016-10-01

    Electrode materials play a decisive role in almost all electrochemical energy storage devices, determining their overall performance. Proper selection, design and fabrication of electrode materials have thus been regarded as one of the most critical steps in achieving high electrochemical energy storage performance. As an advanced nanotechnology for thin films and surfaces with conformal interfacial features and well controllable deposition thickness, atomic layer deposition (ALD) has been successfully developed for deposition and surface modification of electrode materials, where there are considerable issues of interfacial and surface chemistry at atomic and nanometer scale. In addition, ALD has shown great potential in construction of novel nanostructured active materials that otherwise can be hardly obtained by other processing techniques, such as those solution-based processing and chemical vapor deposition (CVD) techniques. This review focuses on the recent development of ALD for the design and delivery of advanced electrode materials in electrochemical energy storage devices, where typical examples will be highlighted and analyzed, and the merits and challenges of ALD for applications in energy storage will also be discussed.

  16. New insights into the electrode mechanism of lithium sulfur batteries via air-free post-test analysis.

    PubMed

    Chen, Lin; Dietz Rago, Nancy L; Bloom, Ira D; Shaw, Leon L

    2016-08-02

    Effects of the volume expansion and shrinkage of Li2S cathodes on electrochemical cycle life are investigated via post-test analysis without exposure to air. The engineered electrodes that confine volume changes within micro-reactors have significantly longer life than the electrodes without the micro-reactor structure, providing the first unambiguous evidence of the importance of confining volume changes for improved battery performance.

  17. Electrode materials for hydrobromic acid electrolysis in Texas Instruments' solar chemical converter

    SciTech Connect

    Luttmer, J.D.; Konrad, D.; Trachtenberg, I.

    1985-05-01

    Texas Instruments has developed a solar chemical converter (SCC) which converts solar energy into chemical energy via the electrolysis of hydrobromic acid. Various materials were evaluated as anodes and cathodes for the electrolysis of the acid. Emphasis was placed on obtaining low overvoltage electrodes with good long-term stability. Sputtered platinum-iridium thin films were identified as the best choice as the cathode material, and sputtered iridium and iridium oxide thin films were identified as the best choice as anode materials. Electrochemical measurements indicate that low overvoltage losses are encountered on these materials at operating current densitities in the SCC. Accelerated corrosion tests of the materials predict acceptable electrode stability for 20 years in an environment representative of onthe-roof service.

  18. Microbial community structure of different electrode materials in constructed wetland incorporating microbial fuel cell.

    PubMed

    Wang, Junfeng; Song, Xinshan; Wang, Yuhui; Abayneh, Befkadu; Ding, Yi; Yan, Denghua; Bai, Junhong

    2016-12-01

    The microbial fuel cell coupled with constructed wetland (CW-MFC) microcosms were operated under fed-batch mode for evaluating the effect of electrode materials on bioelectricity generation and microbial community composition. Experimental results indicated that the bioenergy output in CW-MFC increased with the substrate concentration; maximum average voltage (177mV) was observed in CW-MFC with carbon fiber felt (CFF). In addition, the four different materials resulted in the formation of significantly different microbial community distribution around the anode electrode. The relative abundance of Proteobacteria in CFF and foamed nickel (FN) was significantly higher than that in stainless steel mesh (SSM) and graphite rod (GR) samples. Notably, the findings indicate that CW-MFC utilizing FN anode electrode could apparently improve relative abundance of Dechloromonas, which has been regarded as a denitrifying and phosphate accumulating microorganism.

  19. 33 CFR 183.222 - Flotation material and air chambers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Flotation material and air... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2 Horsepower General § 183.222 Flotation material and air...

  20. 33 CFR 183.222 - Flotation material and air chambers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Flotation material and air... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2 Horsepower General § 183.222 Flotation material and air...

  1. 33 CFR 183.222 - Flotation material and air chambers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Flotation material and air... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2 Horsepower General § 183.222 Flotation material and air...

  2. 33 CFR 183.112 - Flotation material and air chambers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Flotation material and air... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats § 183.112 Flotation material and air chambers. (a)...

  3. 33 CFR 183.222 - Flotation material and air chambers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Flotation material and air... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2 Horsepower General § 183.222 Flotation material and air...

  4. 33 CFR 183.112 - Flotation material and air chambers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Flotation material and air... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats § 183.112 Flotation material and air chambers. (a)...

  5. 33 CFR 183.222 - Flotation material and air chambers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Flotation material and air chambers. 183.222 Section 183.222 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Boats Rated for Engines of More Than 2 Horsepower General § 183.222 Flotation material and air...

  6. Layered double hydroxide materials coated carbon electrode: New challenge to future electrochemical power devices

    NASA Astrophysics Data System (ADS)

    Djebbi, Mohamed Amine; Braiek, Mohamed; Namour, Philippe; Ben Haj Amara, Abdesslem; Jaffrezic-Renault, Nicole

    2016-11-01

    Layered double hydroxides (LDHs) have been widely used in the past years due to their unique physicochemical properties and promising applications in electroanalytical chemistry. The present paper is going to focus exclusively on magnesium-aluminum and zinc-aluminum layered double hydroxides (MgAl & ZnAl LDHs) in order to investigate the property and structure of active cation sites located within the layer structure. The MgAl and ZnAl LDH nanosheets were prepared by the constant pH co-precipitation method and uniformly supported on carbon-based electrode materials to fabricate an LDH electrode. Characterization by powder x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy revealed the LDH form and well-crystallized materials. Wetting surface properties (hydrophilicity and hydrophobicity) of both prepared LDHs were recorded by contact angle measurement show hydrophilic character and basic property. The electrochemical performance of these hybrid materials was investigated by mainly cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry techniques to identify the oxidation/reduction processes at the electrode/electrolyte interface and the effect of the divalent metal cations in total reactivity. The hierarchy of the modified electrode proves that the electronic conductivity of the bulk material is considerably dependent on the divalent cation and affects the limiting parameter of the overall redox process. However, MgAl LDH shows better performance than ZnAl LDH, due to the presence of magnesium cations in the layers. Following the structural, morphological and electrochemical behavior studies of both synthesized LDHs, the prepared LDH modified electrodes were tested through microbial fuel cell configuration, revealing a remarkable, potential new pathway for high-performance and cost-effective electrode use in electrochemical power devices.

  7. Zinc/air battery R and D research and development of bifunctional oxygen electrode: Tasks I and II, Final report

    SciTech Connect

    Klein, M.; Viswanathan, S.

    1986-12-01

    Studies were conducted of the bifunctional oxygen electrode. The development of a rechargeable metal-oxygen (air) cell has been hampered to a great extent by the lack of a stable and cost effective oxygen electrode capable of use during both charge and discharge. The first type of bifunctional electrode consists of two distinct catalytifc layers. The oxygen reduction catalyst layer containing a supported gold catalyst is in contact with a hydrophilic nickel layer in which evolution of oxygen takes place. Loadings of gold from 0.5 to 1.0 mg/cm/sup 2/ were investigated; carbon, graphite, metal, and spinel oxides were evaluated as substrates. The second part of the research effort was centered on developing a reversible oxygen electrode containing only one catalytic layer for both reduction and evolution of oxygen. The work was directed specifically to the study of perovskite type of oxides with the composition AA/sup 1/BO/sub 3/ where A is an element of the lanthanide series, A/sup 1/ is an alkaline earth metal and B, a first row transition element. Initial polarization data obtained in unscrubbed air gave a value of approximately 200 millivolts vs Hg/HgO reference electrode at a current density of 50 ma/cm/sup 2/. Electrodes were made both by roll-bonding and by pelletizing techniques and tested for polarization and cycle life. This study also indicates the optimum process conditions for the manufacture of oxides and fabrication of electrodes.

  8. Graphene-carbon nanotube hybrid materials and use as electrodes

    DOEpatents

    Tour, James M.; Zhu, Yu; Li, Lei; Yan, Zheng; Lin, Jian

    2016-09-27

    Provided are methods of making graphene-carbon nanotube hybrid materials. Such methods generally include: (1) associating a graphene film with a substrate; (2) applying a catalyst and a carbon source to the graphene film; and (3) growing carbon nanotubes on the graphene film. The grown carbon nanotubes become covalently linked to the graphene film through carbon-carbon bonds that are located at one or more junctions between the carbon nanotubes and the graphene film. In addition, the grown carbon nanotubes are in ohmic contact with the graphene film through the carbon-carbon bonds at the one or more junctions. The one or more junctions may include seven-membered carbon rings. Also provided are the formed graphene-carbon nanotube hybrid materials.

  9. Molecular Engineering with Organic Carbonyl Electrode Materials for Advanced Stationary and Redox Flow Rechargeable Batteries.

    PubMed

    Zhao, Qing; Zhu, Zhiqiang; Chen, Jun

    2017-04-03

    Organic carbonyl electrode materials that have the advantages of high capacity, low cost and being environmentally friendly, are regarded as powerful candidates for next-generation stationary and redox flow rechargeable batteries (RFBs). However, low carbonyl utilization, poor electronic conductivity and undesired dissolution in electrolyte are urgent issues to be solved. Here, we summarize a molecular engineering approach for tuning the capacity, working potential, concentration of active species, kinetics, and stability of stationary and redox flow batteries, which well resolves the problems of organic carbonyl electrode materials. As an example, in stationary batteries, 9,10-anthraquinone (AQ) with two carbonyls delivers a capacity of 257 mAh g(-1) (2.27 V vs Li(+) /Li), while increasing the number of carbonyls to four with the formation of 5,7,12,14-pentacenetetrone results in a higher capacity of 317 mAh g(-1) (2.60 V vs Li(+) /Li). In RFBs, AQ, which is less soluble in aqueous electrolyte, reaches 1 M by grafting -SO3 H with the formation of 9,10-anthraquinone-2,7-disulphonic acid, resulting in a power density exceeding 0.6 W cm(-2) with long cycling life. Therefore, through regulating substituent groups, conjugated structures, Coulomb interactions, and the molecular weight, the electrochemical performance of carbonyl electrode materials can be rationally optimized. This review offers fundamental principles and insight into designing advanced carbonyl materials for the electrodes of next-generation rechargeable batteries.

  10. Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries using Synchrotron Radiation Techniques

    SciTech Connect

    Mehta, Apurva; Stanford Synchrotron Radiation Lightsource; Doeff, Marca M.; Chen, Guoying; Cabana, Jordi; Richardson, Thomas J.; Mehta, Apurva; Shirpour, Mona; Duncan, Hugues; Kim, Chunjoong; Kam, Kinson C.; Conry, Thomas

    2013-04-30

    We describe the use of synchrotron X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) techniques to probe details of intercalation/deintercalation processes in electrode materials for Li ion and Na ion batteries. Both in situ and ex situ experiments are used to understand structural behavior relevant to the operation of devices.

  11. Recent Advances in Polymeric Materials Used as Electron Mediators and Immobilizing Matrices in Developing Enzyme Electrodes

    PubMed Central

    Moyo, Mambo; Okonkwo, Jonathan O.; Agyei, Nana M.

    2012-01-01

    Different classes of polymeric materials such as nanomaterials, sol-gel materials, conducting polymers, functional polymers and biomaterials have been used in the design of sensors and biosensors. Various methods have been used, for example from direct adsorption, covalent bonding, crossing-linking with glutaraldehyde on composites to mixing the enzymes or use of functionalized beads for the design of sensors and biosensors using these polymeric materials in recent years. It is widely acknowledged that analytical sensing at electrodes modified with polymeric materials results in low detection limits, high sensitivities, lower applied potential, good stability, efficient electron transfer and easier immobilization of enzymes on electrodes such that sensing and biosensing of environmental pollutants is made easier. However, there are a number of challenges to be addressed in order to fulfill the applications of polymeric based polymers such as cost and shortening the long laboratory synthetic pathways involved in sensor preparation. Furthermore, the toxicological effects on flora and fauna of some of these polymeric materials have not been well studied. Given these disadvantages, efforts are now geared towards introducing low cost biomaterials that can serve as alternatives for the development of novel electrochemical sensors and biosensors. This review highlights recent contributions in the development of the electrochemical sensors and biosensors based on different polymeric material. The synergistic action of some of these polymeric materials and nanocomposites imposed when combined on electrode during sensing is discussed. PMID:22368503

  12. The Science of Electrode Materials for Lithium Batteries

    SciTech Connect

    Fultz, Brent

    2007-03-15

    Rechargeable lithium batteries continue to play the central role in power systems for portable electronics, and could play a role of increasing importance for hybrid transportation systems that use either hydrogen or fossil fuels. For example, fuel cells provide a steady supply of power, whereas batteries are superior when bursts of power are needed. The National Research Council recently concluded that for dismounted soldiers "Among all possible energy sources, hybrid systems provide the most versatile solutions for meeting the diverse needs of the Future Force Warrior. The key advantage of hybrid systems is their ability to provide power over varying levels of energy use, by combining two power sources." The relative capacities of batteries versus fuel cells in a hybrid power system will depend on the capabilities of both. In the longer term, improvements in the cost and safety of lithium batteries should lead to a substantial role for electrochemical energy storage subsystems as components in fuel cell or hybrid vehicles. We have completed a basic research program for DOE BES on anode and cathode materials for lithium batteries, extending over 6 years with a 1 year phaseout period. The emphasis was on the thermodynamics and kinetics of the lithiation reaction, and how these pertain to basic electrochemical properties that we measure experimentally — voltage and capacity in particular. In the course of this work we also studied the kinetic processes of capacity fade after cycling, with unusual results for nanostructued Si and Ge materials, and the dynamics underlying electronic and ionic transport in LiFePO4. This document is the final report for this work.

  13. Is Cu a stable electrode material in hybrid perovskite solar cells for a 30-year lifetime?

    DOE PAGES

    Zhao, Jingjing; Zheng, Xiaopeng; Deng, Yehao; ...

    2016-10-28

    One grand challenge for long-lived perovskite solar cells is that the common electrode materials in solar cells, such as silver and aluminum or even gold, strongly react with hybrid perovskites. Here we report the evaluation of the potential of copper (Cu) as the electrode material in perovskite solar cells for long-term stability. In encapsulated devices which limit exposure to oxygen and moisture, Cu in direct contact with CH3NH3PbI3 showed no reaction at laboratory time scales, and is predicted to be stable for almost 170 years at room temperature and over 22 years at the nominal operating cell temperature of 40more » °C. No diffusion of Cu into CH3NH3PbI3 has been observed after thermal annealing for over 100 hours at 80 °C, nor does Cu cause charge trap states in direct contact with CH3NH3PbI3 after long-term thermal annealing or illumination. High performance devices with efficiency above 20% with Cu electrode retains 98% of the initial efficiency after 816 hours storage in ambient environment without encapsulation. Finally, the results indicate Cu is a promising low-cost electrode material for perovskite solar cells for long-term operation.« less

  14. Is Cu a stable electrode material in hybrid perovskite solar cells for a 30-year lifetime?

    SciTech Connect

    Zhao, Jingjing; Zheng, Xiaopeng; Deng, Yehao; Li, Tao; Shao, Yuchuan; Gruverman, Alexei; Shield, Jeffrey; Huang, Jinsong

    2016-10-28

    One grand challenge for long-lived perovskite solar cells is that the common electrode materials in solar cells, such as silver and aluminum or even gold, strongly react with hybrid perovskites. Here we report the evaluation of the potential of copper (Cu) as the electrode material in perovskite solar cells for long-term stability. In encapsulated devices which limit exposure to oxygen and moisture, Cu in direct contact with CH3NH3PbI3 showed no reaction at laboratory time scales, and is predicted to be stable for almost 170 years at room temperature and over 22 years at the nominal operating cell temperature of 40 °C. No diffusion of Cu into CH3NH3PbI3 has been observed after thermal annealing for over 100 hours at 80 °C, nor does Cu cause charge trap states in direct contact with CH3NH3PbI3 after long-term thermal annealing or illumination. High performance devices with efficiency above 20% with Cu electrode retains 98% of the initial efficiency after 816 hours storage in ambient environment without encapsulation. Finally, the results indicate Cu is a promising low-cost electrode material for perovskite solar cells for long-term operation.

  15. Nanostructured core-shell electrode materials for electrochemical capacitors

    NASA Astrophysics Data System (ADS)

    Jiang, Long-bo; Yuan, Xing-zhong; Liang, Jie; Zhang, Jin; Wang, Hou; Zeng, Guang-ming

    2016-11-01

    Core-shell nanostructure represents a unique system for applications in electrochemical energy storage devices. Owing to the unique characteristics featuring high power delivery and long-term cycling stability, electrochemical capacitors (ECs) have emerged as one of the most attractive electrochemical storage systems since they can complement or even replace batteries in the energy storage field, especially when high power delivery or uptake is needed. This review aims to summarize recent progress on core-shell nanostructures for advanced supercapacitor applications in view of their hierarchical architecture which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The core-shell nanostructures include carbon/carbon, carbon/metal oxide, carbon/conducting polymer, metal oxide/metal oxide, metal oxide/conducting polymer, conducting polymer/conducting polymer, and even more complex ternary core-shell nanoparticles. The preparation strategies, electrochemical performances, and structural stabilities of core-shell materials for ECs are summarized. The relationship between core-shell nanostructure and electrochemical performance is discussed in detail. In addition, the challenges and new trends in core-shell nanomaterials development have also been proposed.

  16. PEDOT-based composites as electrode materials for supercapacitors

    NASA Astrophysics Data System (ADS)

    Zhao, Zhiheng; Richardson, Georgia F.; Meng, Qingshi; Zhu, Shenmin; Kuan, Hsu-Chiang; Ma, Jun

    2016-01-01

    Poly (3, 4-ethylenedioxythiophene) (denoted PEDOT) already has a brief history of being used as an active material in supercapacitors. It has many advantages such as low-cost, flexibility, and good electrical conductivity and pseudocapacitance. However, the major drawback is low stability, which means an obvious capacitance drop after a certain number of charge-discharge cycles. Another disadvantage is its limited capacitance and this becomes an issue for industrial applications. To solve these problems, there are several approaches including the addition of conducting nanofillers to increase conductivity, and mixing or depositing metal oxide to enhance capacitance. Furthermore, expanding the surface area of PEDOT is one of the main methods to improve its performance in energy storage applications through special processes; for example using a three-dimensional substrate or preparing PEDOT aerogel through freeze drying. This paper reviews recent techniques and outcomes of PEDOT based composites for supercapacitors, as well as detailed calculations about capacitances. Finally, this paper outlines the new direction and recent challenges of PEDOT based composites for supercapacitor applications.

  17. Method of preparing an electrode material of lithium-aluminum alloy

    DOEpatents

    Settle, Jack L.; Myles, Kevin M.; Battles, James E.

    1976-01-01

    A solid compact having a uniform alloy composition of lithium and aluminum is prepared as a negative electrode for an electrochemical cell. Lithium losses during preparation are minimized by dissolving aluminum within a lithium-rich melt at temperatures near the liquidus temperatures. The desired alloy composition is then solidified and fragmented. The fragments are homogenized to a uniform composition by annealing at a temperature near the solidus temperature. After comminuting to fine particles, the alloy material can be blended with powdered electrolyte and pressed into a solid compact having the desired electrode shape. In the preparation of some electrodes, an electrically conductive metal mesh is embedded into the compact as a current collector.

  18. MgO-templated carbon as a negative electrode material for Na-ion capacitors

    NASA Astrophysics Data System (ADS)

    Kado, Yuya; Soneda, Yasushi

    2016-12-01

    In this study, MgO-templated carbon with different pore structures was investigated as a negative electrode material for Na-ion capacitors. With increasing the Brunauer-Emmett-Teller surface area, the irreversible capacity increased, and the coulombic efficiency of the 1st cycle decreased because of the formation of solid electrolyte interface layers. MgO-templated carbon annealed at 1000 °C exhibited the highest capacity and best rate performance, suggesting that an appropriate balance between surface area and crystallinity is imperative for fast Na-ion storage, attributed to the storage mechanism: combination of non-faradaic electric double-layer capacitance and faradaic Na intercalation in the carbon layers. Finally, a Na-ion capacitor cell using MgO-templated carbon and activated carbon as the negative and positive electrodes, respectively, exhibited an energy density at high power density significantly greater than that exhibited by the cell using a commercial hard carbon negative electrode.

  19. Glow Discharge Emission Spectra in Air with Liquid Electrode Based on Distilled Water

    NASA Astrophysics Data System (ADS)

    Chuchman, M. P.; Mesarosz, L. V.; Shuaibov, A. K.; Kiris, V. V.; Tarasenko, N. V.

    2016-11-01

    The results of spectroscopic studies of a glow discharge plasma at atmospheric pressure in air with an electrode based on distilled water are presented. The parametric effects affecting the discharge emission are analyzed. The dependence of the emission intensity of the various discharge components and their spatial localization in the discharge gap on the current strength is explained by change in the discharge geometry and the conditions of oxidation with increase of the current. It is shown that the composition of the gas mixture in the electrode gap changes with increase of the discharge current from nitrogen-rich (12-19 mA) to rich in water vapor and its dissociation products (19-24 mA). At higher currents, the gas mixture is also rich in the products of plasma chemical reactions and nitric oxide in particular. The redistribution of the radiation intensity of the molecules of nitrogen and its oxide with increase of the current occurs mainly in the cathode region (at the plasma-fluid boundary), where the formation of oxides is improved as a result of increase in the amount of vaporized solution and in the effectiveness of oxidation reactions with increase of the water temperature and discharge current.

  20. Magnetically Diffused Radial Electric-Arc Air Heater Employing Water-Cooled Copper Electrodes

    NASA Technical Reports Server (NTRS)

    Mayo, R. F.; Davis, D. D., Jr.

    1962-01-01

    A magnetically rotated electric-arc air heater has been developed that is novel in that an intense magnetic field of the order of 10,000 to 25,000 gauss is employed. This field is supplied by a coil that is connected in series with the arc. Experimentation with this heater has shown that the presence of an intense magnetic field transverse to the arc results in diffusion of the arc and that the arc has a positive effective resistance. With the field coil in series with the arc, highly stable arc operation is obtained from a battery power supply. External ballast is not required to stabilize the arc when it is operating at maximum power level. The electrode erosion rate is so low that the airstream contamination is no more than 0.07 percent and may be substantially less.

  1. Materials and fabrication of electrode scaffolds for deposition of MnO2 and their true performance in supercapacitors

    NASA Astrophysics Data System (ADS)

    Cao, Jianyun; Li, Xiaohong; Wang, Yaming; Walsh, Frank C.; Ouyang, Jia-Hu; Jia, Dechang; Zhou, Yu

    2015-10-01

    MnO2 is a promising electrode material for high energy supercapacitors because of its large pseudo-capacitance. However, MnO2 suffers from low electronic conductivity and poor cation diffusivity, which results in poor utilization and limited rate performance of traditional MnO2 powder electrodes, obtained by pressing a mixed paste of MnO2 powder, conductive additive and polymer binder onto metallic current collectors. Developing binder-free MnO2 electrodes by loading nanoscale MnO2 deposits on pre-fabricated device-ready electrode scaffolds is an effective way to achieve both high power and energy performance. These electrode scaffolds, with interconnected skeletons and pore structures, will not only provide mechanical support and electron collection as traditional current collectors but also fast ion transfer tunnels, leading to high MnO2 utilization and rate performance. This review covers design strategies, materials and fabrication methods for the electrode scaffolds. Rational evaluation of the true performance of these electrodes is carried out, which clarifies that some of the electrodes with as-claimed exceptional performances lack potential in practical applications due to poor mass loading of MnO2 and large dead volume of inert scaffold materials/void spaces in the electrode structure. Possible ways to meet this challenge and bring MnO2 electrodes from laboratory studies to real-world applications are considered.

  2. Mapping redox energies of electrode materials for lithium batteries

    NASA Astrophysics Data System (ADS)

    Padhi, Akshaya Kumar

    A comparative study of oxides containing tetrahedral polyanions forming 3D-framework host structures with octahedral-site transition-metal oxidant cations addresses the following issues: (i) Chemical versatility of the framework structures allows one to determine the redox couples for different transition-metal cations with respect to the Fermi energy of a lithium anode and how they vary with changes of host structure, choice of polyanion, or degree of lithiation. (ii) Exploration of the advantage of a more open framework for Li+-ion diffusion versus the disadvantage of polaronic conduction. (iii) Identification of the cause of a reversible capacity fade with increasing current density. (iv) The design of new materials for secondary batteries. Variation of a redox energy at an M atom in an oxide depends on two factors: (a) the Madelung energy of the cation and (b) the covalent contribution to the M-O bonding, which may be modulated by a counter cation through the inductive effect. Electrochemical characterization of the spinel system Li1+x[ Mn1.5M0.5] O4, M = Co or Ni, indicates an overlap of the Mn4+/Mn3+ and M3+/M2+ redox energies at x = 0.5. The family of V (LiM) O4 spinels with M = Mn, Co or Ni has M3+/M2+ redox couples at 3.8, 4.2, and 4.8 eV, respectively, below the Fermi energy of a lithium anode, which indicates formation of (VO4)3- polyanions. Replacement of VO4 by PO4 yields ordered- olivine structures LiMPO4; Li1-xFePO4 and Li1-xFe0.5Mn0.5PO4 show Fe3+/Fe2+ and Mn3+/Mn2+ redox couples at 3.4 and 4.1 V vs. lithium, respectively. Reversible Li insertion into FePO4 retains a 3.4 V plateau vs. lithium with increasing current density, but shows a capacity that fades reversibly with current density as a result of a dynamic process. A change of about 0.8 eV between isostructural sulfates and phosphates for the Ti4/Ti3+, V3+/V2+ and Fe3+/Fe2+ couples is due to the inductive effect. These shifts illustrate that the relative positions of the redox energies remain

  3. Microbial fuel cells: the effects of configurations, electrolyte solutions, and electrode materials on power generation.

    PubMed

    Li, Fengxiang; Sharma, Yogesh; Lei, Yu; Li, Baikun; Zhou, Qixing

    2010-01-01

    This objective of this study is to conduct a systematic investigation of the effects of configurations, electrolyte solutions, and electrode materials on the performance of microbial fuel cells (MFC). A comparison of voltage generation, power density, and acclimation period of electrogenic bacteria was performed for a variety of MFCs. In terms of MFC configuration, membrane-less two-chamber MFCs (ML-2CMFC) had lower internal resistance, shorter acclimation period, and higher voltage generation than the conventional two-chamber MFCs (2CMFC). In terms of anode solutions (as electron donors), the two-chamber MFCs fed with anaerobic treated wastewater (AF-2CMFCs) had the power density 19 times as the two-chamber MFCs fed with acetate (NO(3)(-)2CMFCs). In terms of cathode solutions (as electron acceptors), AF-2CMFCs with ferricyanide had higher voltage generation than that of ML-2CMFCs with nitrate (NO(3)(-)ML-2CMFCs). In terms of electrode materials, ML-2CMFCs with granular-activated carbon as the electrode (GAC-ML-2CMFCs) had a power density 2.5 times as ML-2CMFCs with carbon cloth as the electrode. GAC-ML-2CMFCs had the highest columbic efficiency and power output among all the MFCs tested, indicating that the high surface area of GAC facilitate the biofilm formation, accelerate the degradation of organic substrates, and improve power generation.

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

    PubMed Central

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

    2015-01-01

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

  5. Thermal-stability studies of electrode materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Jiang, Junwei

    2005-07-01

    The thermal stability of lithium-ion batteries has recently attracted attention for two major reasons. (1) Attempts to make large-size cells used in power tools, E-bikes and EVs. Large cells have lower surface area to volume ratios and hence heat dissipation is more problematic than 18650-size cells. Safety problems, therefore, for large cells are more serious. (2) Next generation high-capacity electrodes will increase the energy density of lithium-ion cells meaning even an 18650-size cell may face safety concerns. This thesis presents studies of the thermal stability of electrode materials in electrolytes to understand their reactivity. A search for new positive electrode materials with high thermal stability was made. The thermal stability of two common electrode materials (Li0.81 C6 and Li0.5CoO2) in lithium-ion cells was studied by Accelerating Rate Calorimeter (ARC). Li0.81C 6 has much lower reactivity with lithium bis(oxalato)borate (LiBOB) electrolyte compared to LiPF6 electrolyte. It is not the case, however, for Li0.5CoO2. Oven tests of full LiCoO 2/C 18650-size cells with LiBOB or LiPF6 electrolytes, confirmed the ARC results. ARC was then used to study the reactivity of existing electrode materials. The thermal stability of a negative electrode material was found to increase with the binding energy of Li atoms hosted in the material. Li0.5VO 2 (B) has a higher lithium binding energy (2.45 eV vs. Li) than Li 0.81C6 (0.1 eV vs. Li) and Li7Ti5O 12 (1.55 eV) and it shows the highest thermal stability in EC/DEC among the three materials. The reactivity of two existing positive electrode materials, LiMn2O4 and LiFePO4, was studied. Cell systems expected to be highly tolerant to thermal abuse were suggested: LiFePO 4/C or Li4Ti5O12 in LiBOB electrolytes. The system, x Li[Ni1/2Mn1/2]O2 • y LiCoO2 • z Li[Li1/3Mn2/3]O2 (x + y + z = 1), was explored for new positive electrode materials with large capacity and high thermal stability. Li[(Ni0.5Mn0.5) xCo1-x]O2 (0

  6. Evaluation of materials proposed for the construction of the Plasma Electrode Pockels Cell (PEPC) on beamlet

    NASA Astrophysics Data System (ADS)

    Roberts, D.; Robb, C.; Deyoreo, J.; Atherton, J.

    1992-11-01

    The proposed upgrade of the NOVA laser system at Lawrence Livermore National Laboratory employs a multipass architecture that requires an optical switch to emit the laser light at the appropriate fluence. This Pockels cell-based optical switch does not use traditional ring or thin-film electrodes because of the large aperture and high fluence of the laser system. Rather, it uses a plasma electrode Pockels cell with a KD*P crystal as the electro-optical medium. A discharge plasma is formed on each side of the electro-optic crystal and high voltage is applied across the crystal through the plasma electrode to initiate optical switching. In October 1991 we began evaluating materials suggested for the large aperture plasma electrode optical switch. Previous experiments suggested that switching performance could be significantly affected by the deterioration of cell materials. The final prototype switch tested used polyethylene for the switch body, Mykroy for the mid-plane and a silicone vulcanite to encapsulate the KD*P crystal. The encapsulant easily compensated for the effect of assembling the optical switch and no strain-induced birefringence in the crystal after encapsulation was measured. Oxygen was eventually added to the plasma to react with the sputtered carbon from the cathode and produce a gaseous effluent. As an added benefit, the production of ozone absorbed most of the ultraviolet radiation affecting the encapsulant. All the materials tested decomposed and produced volatiles, although no change in the damage threshold of exposed optical surfaces tested to date was seen. An evaluation of the recommended materials for major cell components using published manufacturers data, experimental results from our Material Evaluation Apparatus, and outgassing performance and sputtering data produced at the Laboratory's Vacuum Process Lab is presented.

  7. Nickel-Tin Electrode Materials for Nonaqueous Li-Ion Cells

    NASA Technical Reports Server (NTRS)

    Ehrlich, Grant M.; Durand, Christopher

    2005-01-01

    Experimental materials made from mixtures of nickel and tin powders have shown promise for use as the negative electrodes of rechargeable lithium-ion electrochemical power cells. During charging (or discharging) of a lithium-ion cell, lithium ions are absorbed into (or desorbed from, respectively) the negative electrode, typically through an intercalation or alloying process. The negative electrodes (for this purpose, designated as anodes) in state-of-the-art Li-ion cells are made of graphite, in which intercalation occurs. Alternatively, the anodes can be made from metals, in which alloying can occur. For reasons having to do with the electrochemical potential of intercalated lithium, metallic anode materials (especially materials containing tin) are regarded as safer than graphite ones; in addition, such metallic anode materials have been investigated in the hope of obtaining reversible charge/discharge capacities greater than those of graphite anodes. However, until now, each of the tin-containing metallic anode formulations tested has been found to be inadequate in some respect.

  8. Metal-air cell with ion exchange material

    DOEpatents

    Friesen, Cody A.; Wolfe, Derek; Johnson, Paul Bryan

    2015-08-25

    Embodiments of the invention are related to anion exchange membranes used in electrochemical metal-air cells in which the membranes function as the electrolyte material, or are used in conjunction with electrolytes such as ionic liquid electrolytes.

  9. 33 CFR 183.112 - Flotation material and air chambers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats § 183.112 Flotation material and air chambers. (a)...

  10. 33 CFR 183.112 - Flotation material and air chambers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats § 183.112 Flotation material and air chambers. (a)...

  11. 33 CFR 183.112 - Flotation material and air chambers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats § 183.112 Flotation material and air chambers. (a)...

  12. Nanomechanical and Electro-mechanical Characterization of Materials for Flexible Electrodes Applications

    NASA Astrophysics Data System (ADS)

    Peng, Cheng

    Flexible electronics attract research and commercial interests in last 2 decades for its flexibility, low cost, light weight and etc. To develop and improve the electro-mechanical properties of flexible electrodes is the most critical and important step. In this work, we have performed nanomechanical and electromechanical characterization of materials for flexible electrode applications, including metallic nanowires (NWs), indium tin oxide (ITO)-based and carbon nanotube (CNT)-based electrodes. First, we designed and developed four different testing platforms for nanomechanical and electro-mechanical characterization purpose. For the nano/sub-micro size samples, the micro mechanical devices can be used for uniaxial and bi-axial loading tests. For the macro size samples, the micro tester will be used for in situ monotonic tensile test, while the fatigue tester can be used for in situ cyclic tensile or bending testing purpose. Secondly, we have investigated mechanical behaviors of single crystalline Ni nanowires and single crystalline Cu nanowires under uni-axial tensile loading inside a scanning electron microscope (SEM) chamber. We demonstrated both size and strain-rate dependence on yield stress of single-crystalline Ni NWs with varying diameters (from 100 nm to 300 nm), and the molecular dynamics (MD) simulation helped to confirm and understand the experimental phenomena. Also, two different fracture modes, namely ductile and brittle-like fractures, were found in the same batch of Cu nanowire samples. Finally, we studied the electro-mechanical behaviors of flexible electrodes in macro scale. We reported a coherent study integrating in situ electro-mechanical experiments and mechanics modeling to decipher the failure mechanics of ITO-based and CNTbased electrodes under tension. It is believed that our combined experimental and simulation results provide some further insights into the important yet complicated deformation mechanisms for nanoscale metals and

  13. Temperature Prediction in a Free-Burning Arc and Electrodes for Nanostructured Materials and Systems.

    PubMed

    Lee, Won-Ho; Kim, Youn-Jea; Lee, Jong-Chul

    2015-11-01

    Temperature in a free-burning arc used for synthesis of nanoparticles and nanostructured materials is generally around 20,000 K just below the cathode, falling to about 15,000 K just above the anode, and decreasing rapidly in the radial direction. Therefore, the electrode erosion is indispensable for these atmospheric plasma systems, as well as for switching devices, due to the high heat flux transferred from high temperature arcs to electrodes, but experimental and theoretical works have not identified the characteristic phenomena because of the complex physical processes. To the previous study, we have focused on the arc self-induced fluid flow in a free-burning arc using the computational fluid dynamics (CFD) technique. At this time, our investigation is concerned with the whole region of free-burning high-intensity arcs including the tungsten cathode, the arc plasma and the anode using a unified numerical model for applying synthesis of nanoparticles and nanostructured materials practically.

  14. Electrodes and electrochemical storage cells utilizing tin-modified active materials

    DOEpatents

    Anani, Anaba; Johnson, John; Lim, Hong S.; Reilly, James; Schwarz, Ricardo; Srinivasan, Supramaniam

    1995-01-01

    An electrode has a substrate and a finely divided active material on the substrate. The active material is ANi.sub.x-y-z Co.sub.y Sn.sub.z, wherein A is a mischmetal or La.sub.1-w M.sub.w, M is Ce, Nd, or Zr, w is from about 0.05 to about 1.0, x is from about 4.5 to about 5.5, y is from 0 to about 3.0, and z is from about 0.05 to about 0.5. An electrochemical storage cell utilizes such an electrode as the anode. The storage cell further has a cathode, a separator between the cathode and the anode, and an electrolyte.

  15. Black Conductive Titanium Oxide High-Capacity Materials for Battery Electrodes

    SciTech Connect

    Han, W.

    2011-05-18

    Stoichiometric titanium dioxide (TiO{sub 2}) is one of the most widely studied transitionmetal oxides because of its many potential applications in photoelectrochemical systems, such as dye-sensitized TiO{sub 2} electrodes for photovoltaic solar cells, and water-splitting catalysts for hydrogen generation, and in environmental purification for creating or degrading specific compounds. However, TiO{sub 2} has a wide bandgap and high electrical resistivity, which limits its use as an electrode. A set of non-stoichiometric titanium oxides called the Magneli phases, having a general formula of Ti{sub n}O{sub 2n-1} with n between 4 and 10, exhibits lower bandgaps and resistivities, with the highest electrical conductivities reported for Ti{sub 4}O{sub 7}. These phases have been formulated under different conditions, but in all reported cases the resulting oxides have minimum grain sizes on the order of micrometers, regardless of the size of the starting titanium compounds. In this method, nanoparticles of TiO{sub 2} or hydrogen titanates are first coated with carbon using either wet or dry chemistry methods. During this process the size and shape of the nanoparticles are 'locked in.' Subsequently the carbon-coated nanoparticles are heated. This results in the transformation of the original TiO{sub 2} or hydrogen titanates to Magneli phases without coarsening, so that the original size and shape of the nanoparticles are maintained to a precise degree. People who work on batteries, fuel cells, ultracapacitors, electrosynthesis cells, electro-chemical devices, and soil remediation have applications that could benefit from using nanoscale Magneli phases of titanium oxide. Application of these electrode materials may not be limited to substitution for TiO{sub 2} electrodes. Combining the robustness and photosensitivity of TiO{sub 2} with higher electrical conductivity may result in a general electrode material.

  16. Silver-Copper Nanoalloy Catalyst Layer for Bifunctional Air Electrodes in Alkaline Media.

    PubMed

    Wu, Xiaoqiang; Chen, Fuyi; Jin, Yachao; Zhang, Nan; Johnston, Roy L

    2015-08-19

    A carbon-free and binder-free catalyst layer composed of a Ag-Cu nanoalloy on Ni foam was used as the air cathode in a zinc-air battery for the first time. The Ag-Cu catalyst was prepared using pulsed laser deposition. The structures of the catalysts were found to consist of crystalline Ag-Cu nanoalloy particles with an average size of 2.58 nm embedded in amorphous Cu films. As observed in the X-ray photoelectron spectra, the Ag 3d core levels shifted to higher binding energies, whereas the Cu 2p core levels shifted to lower binding energies, indicating alloying of the silver and copper. Rotating disk electrode measurements indicated that the oxygen reduction reaction (ORR) proceeded through a four-electron pathway on the Ag50Cu50 and Ag90Cu10 nanoalloy catalysts in alkaline solution. Moreover, the catalytic activity of Ag50Cu50 in the ORR is more efficient than that of Ag90Cu10. By performing charge and discharge cycling measurements, the Ag50Cu50 catalyst layer was confirmed to have a maximum power density of approximately 86.3 mW cm(-2) and an acceptable cell voltage at 0.863 V for current densities up to 100 mA cm(-2) in primary zinc-air batteries. In addition, a round-trip efficiency of approximately 50% at a current density of 20 mA cm(-2) was also obtained in the test.

  17. Hydridable material for the negative electrode in a nickel-metal hydride storage battery

    DOEpatents

    Knosp, Bernard; Bouet, Jacques; Jordy, Christian; Mimoun, Michel; Gicquel, Daniel

    1997-01-01

    A monophase hydridable material for the negative electrode of a nickel-metal hydride storage battery with a "Lave's phase" structure of hexagonal C14 type (MgZn.sub.2) has the general formula: Zr.sub.1-x Ti.sub.x Ni.sub.a Mn.sub.b Al.sub.c Co.sub.d V.sub.e where ##EQU1##

  18. Electrochemical properties of lithium air batteries with Pt100-xRux (0 ≤ x ≤ 100) electrocatalysts for air electrodes

    NASA Astrophysics Data System (ADS)

    Yui, Yuhki; Sakamoto, Shuhei; Nohara, Masaya; Hayashi, Masahiko; Nakamura, Jiro; Komatsu, Takeshi

    2017-02-01

    Electrochemical properties of lithium air secondary battery cells with Pt100-xRux (0 ≤ x ≤ 100) electrocatalysts, prepared by the formic acid reduction method and loaded into air electrodes were examined in 1 mol/l LiTFSA/TEGDME electrolyte solution. Among the cells, the one with the Pt10Ru90 (x = 90)/carbon sample showed the largest discharge capacity of 1014 mAh/g and the lowest average charge voltage of 3.74 V. In addition, the x = 90 sample showed comparatively good cycle stability with discharge capacity of over 800 mAh/g at the 8th cycle. As a result, x = 90 was confirmed to be the optimized composition as the electrocatalyst for the air electrode.

  19. Nickel/silicon core/shell nanosheet arrays as electrode materials for lithium ion batteries

    SciTech Connect

    Huang, X.H. Zhang, P.; Wu, J.B.; Lin, Y.; Guo, R.Q.

    2016-08-15

    Highlights: • Ni nanosheet arrays is the core and Si layer is the shell. • Ni nanosheet arrays act as a three-dimensional current collector to support Si. • Ni nanosheet arrays can improve the conductivity and stability of the electrode. • Ni/Si nanosheet arrays exhibit excellent cyclic and rate performance. - Abstract: Ni/Si core/shell nanosheet arrays are proposed to enhance the electrochemical lithium-storage properties of silicon. The arrays are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The arrays are micro-sized in height, which are constructed by interconnected Ni nanosheet as the core and Si coating layer as the shell. The electrochemical properties as anode materials of lithium ion batteries are investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge tests. The arrays can achieve high reversible capacity, good cycle stability and high rate capability. It is believed that the enhanced electrochemical performance is attributed to the electrode structure, because the interconnected Ni nanosheet can act as a three-dimensional current collector, and it has the ability of improving the electrode conductivity, enlarging the electrochemical reaction interface, and suppressing the electrode pulverization.

  20. The effect of electrode material on the electrogenerated chemiluminescence of luminol

    SciTech Connect

    Vitt, J.E.; Johnson, D.C. ); Engstrom, R.C. )

    1991-06-01

    This paper reports on the oxidation of luminol and its concomitant electrogenerated chemiluminescence (ECL) which were studied at several electrode materials by voltammetry and chronoamperometry. The ECL intensity (I{sub ECL}) was inversely related to the activity of the electrodes. The lowest I{sub ECL}) was measured when luminol was oxidized to 3-aminophthalate (n {approx equal}4 eq mol{sup {minus}1}) at a nearly mass-transport limited rate at glassy carbon. The ECL kinetics were studied and the order of the reaction with respect to luminol was 3/2 at concentrations to ca. 1 mM when O{sub 2} was the coreactant. In the presence of H{sub 2}O{sub 2}, the ECL reaction was first order with respect to luminol. A reaction mechanism is proposed that is consistent with the inetic data and the inverse relationship between electrode activity and I{sub ECL}. The implications of these results are discussed with respect to imaging the spatial distribution of current density at electrode surfaces, including that of PbO{sub 2} films activated by adsorbed Bi(V). A value of 6.6 {times} 10{sup {minus}6} cm{sup 2} s{sup {minus}1} was determined for the diffusion coefficient of luminol in 0.1M NaOH.

  1. Comparison of carbon materials as electrodes for enzyme electrocatalysis: hydrogenase as a case study.

    PubMed

    Quinson, Jonathan; Hidalgo, Ricardo; Ash, Philip A; Dillon, Frank; Grobert, Nicole; Vincent, Kylie A

    2014-01-01

    We present a study of electrocatalysis by an enzyme adsorbed on a range of carbon materials, with different size, surface area, morphology and graphitic structure, which are either commercially available or prepared via simple, established protocols. We choose as our model enzyme the hydrogenase I from E. coli (Hyd-1), which is an active catalyst for H2 oxidation, is relatively robust and has been demonstrated in H2 fuel cells and H2-driven chemical synthesis. The carbon materials were characterised according to their surface area, surface morphology and graphitic character, and we use the electrocatalytic H2 oxidation current for Hyd-1 adsorbed on these materials to evaluate their effectiveness as enzyme electrodes. Here, we show that a variety of carbon materials are suitable for adsorbing hydrogenases in an electroactive configuration. This unified study provides insight into selection and design of carbon materials for study of redox enzymes and different applications of enzyme electrocatalysis.

  2. The reaction current distribution in battery electrode materials revealed by XPS-based state-of-charge mapping.

    PubMed

    Pearse, Alexander J; Gillette, Eleanor; Lee, Sang Bok; Rubloff, Gary W

    2016-07-28

    Morphologically complex electrochemical systems such as composite or nanostructured lithium ion battery electrodes exhibit spatially inhomogeneous internal current distributions, particularly when driven at high total currents, due to resistances in the electrodes and electrolyte, distributions of diffusion path lengths, and nonlinear current-voltage characteristics. Measuring and controlling these distributions is interesting from both an engineering standpoint, as nonhomogenous currents lead to lower utilization of electrode material, as well as from a fundamental standpoint, as comparisons between theory and experiment are relatively scarce. Here we describe a new approach using a deliberately simple model battery electrode to examine the current distribution in a electrode material limited by poor electronic conductivity. We utilize quantitative spatially resolved X-ray photoelectron spectroscopy to measure the spatial distribution of the state-of-charge of a V2O5 model electrode as a proxy measure for the current distribution on electrodes discharged at varying current densities. We show that the current at the electrode-electrolyte interface falls off with distance from the current collector, and that the current distribution is a strong function of total current. We compare the observed distributions with a simple analytical model which reproduces the dependence of the distribution on total current, but fails to predict the correct length scale. A more complete numerical simulation suggests that dynamic changes in the electronic conductivity of the V2O5 concurrent with lithium insertion may contribute to the differences between theory and experiment. Our observations should help inform design criteria for future electrode architectures.

  3. Nickel cobalt oxide nanowire-reduced graphite oxide composite material and its application for high performance supercapacitor electrode material.

    PubMed

    Wang, Xu; Yan, Chaoyi; Sumboja, Afriyanti; Lee, Pooi See

    2014-09-01

    In this paper, we report a facile synthesis method of mesoporous nickel cobalt oxide (NiCo2O4) nanowire-reduced graphite oxide (rGO) composite material by urea induced hydrolysis reaction, followed by sintering at 300 degrees C. P123 was used to stabilize the GO during synthesis, which resulted in a uniform coating of NiCo2O4 nanowire on rGO sheet. The growth mechanism of the composite material is discussed in detail. The NiCo2O4-rGO composite material showed an outstanding electrochemical performance of 873 F g(-1) at 0.5 A g(-1) and 512 F g(-1) at 40 A g(-1). This method provides a promising approach towards low cost and large scale production of supercapacitor electrode material.

  4. Pyrometallurgical Extraction of Valuable Elements in Ni-Metal Hydride Battery Electrode Materials

    NASA Astrophysics Data System (ADS)

    Jiang, Yin-ju; Deng, Yong-chun; Bu, Wen-gang

    2015-10-01

    Gas selective reduction-oxidation (redox) and melting separation were consecutively applied to electrode materials of AB5-type Ni-metal hydride batteries leading to the production of a Ni-Co alloy and slag enriched with rare earth oxides (REO). In the selective redox process, electrode materials were treated with H2/H2O at 1073 K and 1173 K (800 °C and 900 °C). Active elements such as REs, Al, and Mn were oxidized whereas relatively inert elements such as Ni and Co were transformed into their elemental states in the treated materials. SiO2 and Al2O3 powders were added into the treated materials as fluxes which were then melted at 1823 K (1550 °C) to yield a Ni-Co alloy and a REO-SiO2-Al2O3-MnO slag. The high-purity Ni-Co alloy produced can be used as a raw material for AB5-type hydrogen-storage alloy. The REO content in slag was very high, i.e., 48.51 pct, therefore it can be used to recycle rare earth oxides.

  5. Emerging Prototype Sodium-Ion Full Cells with Nanostructured Electrode Materials.

    PubMed

    Ren, Wenhao; Zhu, Zixuan; An, Qinyou; Mai, Liqiang

    2017-04-10

    Due to steadily increasing energy consumption, the demand of renewable energy sources is more urgent than ever. Sodium-ion batteries (SIBs) have emerged as a cost-effective alternative because of the earth abundance of Na resources and their competitive electrochemical behaviors. Before practical application, it is essential to establish a bridge between the sodium half-cell and the commercial battery from a full cell perspective. An overview of the major challenges, most recent advances, and outlooks of non-aqueous and aqueous sodium-ion full cells (SIFCs) is presented. Considering the intimate relationship between SIFCs and electrode materials, including structure, composition and mutual matching principle, both the advance of various prototype SIFCs and the electrochemistry development of nanostructured electrode materials are reviewed. It is noted that a series of SIFCs combined with layered oxides and hard carbon are capable of providing a high specific gravimetric energy above 200 Wh kg(-1) , and an NaCrO2 //hard carbon full cell is able to deliver a high rate capability over 100 C. To achieve industrialization of SIBs, more systematic work should focus on electrode construction, component compatibility, and battery technologies.

  6. Development of materials for open-cycle magnetohydrodynamics (MHD): ceramic electrode. Final report

    SciTech Connect

    Bates, J.L.; Marchant, D.D.

    1986-09-01

    Pacific Northwest Laboratory, supported by the US Department of Energy, developed advanced materials for use in open-cycle, closed cycle magnetohydrodynamics (MHD) power generation, an advanced energy conversion system in which the flow of electrically conducting fluid interacts with an electric field to convert the energy directly into electricity. The purpose of the PNL work was to develop electrodes for the MHD channel. Such electrodes must have: (1) electrical conductivity above 0.01 (ohm-cm)/sup -1/ from near room temperature to 1900/sup 0/K, (2) resistance to both electrochemical and chemical corrosion by both slag and potassium seed, (3) resistance to erosion by high-velocity gases and particles, (4) resistance to thermal shock, (5) adequate thermal conductivity, (6) compatibility with other channel components, particularly the electrical insulators, (7) oxidation-reduction stability, and (8) adequate thermionic emission. This report describes the concept and development of high-temperature, graded ceramic composite electrode materials and their electrical and structural properties. 47 refs., 16 figs., 13 tabs.

  7. Recycled Materials - Applications to Air Force Pavements.

    DTIC Science & Technology

    1980-09-01

    an unlimited supply of natural materials. Since the embargo, the law of supply and demand had pushed the price of asphalt to $180 per ton* by early...are a number of reasons for planing the pae,.-%nt surface ( Lawing , 1976). The pavement surface over a bridge can be re- moved by planing before...Donald :. 979. "Recyc.in, Aschalt Pavements," Federal Highway Admistration Demonstration roject N-. 39, Sherburne, Vt., 38 pp. Ga-nnon, Charles R., et

  8. Determination of chromium(VI) in electronics materials using trioctylamine modified carbon paste electrode.

    PubMed

    Xu, Juan; Kong, Yong; Wang, Wenchang; Chen, Zhidong; Yao, Shiping

    2009-12-01

    A trioctylamine (TOA) modified carbon paste electrode (TOA/CPE) was firstly utilized to determine Cr(VI) in electronics materials. The effects of preconcentration conditions, that is, TOA amount and accumulation time on Cr(VI) accumulation were examined and the optimum experiment conditions for the determination were identified. A sensitive reduction peak in the stripping voltammogram at -0.45 V, a characteristic of trace Cr(VI), was detected when the accumulation time was 10 min. Under optimized conditions, TOA/CPE demonstrated an enhanced sensitivity for Cr(VI), providing a low detection limit (S/N = 3) at 3.4 x 10(-9) M. Interference studies also displayed high selectivity of the TOA/CPE for Cr(VI); this electrode can accurately determine Cr(VI) in the presence of Cr(III) (600-fold concentration) and other interfering cations.

  9. The catalytic role of tungsten electrode material in the plasmachemical activity of a pulsed corona discharge in water

    NASA Astrophysics Data System (ADS)

    Lukes, Petr; Clupek, Martin; Babicky, Vaclav; Sisrova, Irena; Janda, Vaclav

    2011-06-01

    The effects of tungsten material used as a high-voltage needle electrode on the production of hydrogen peroxide and the degradation of dimethylsulfoxide (DMSO) caused by a pulsed corona discharge in water were investigated. A reactor of needle-plate electrode geometry was used. The erosion of the tungsten electrodes by the discharge was evaluated. The yields of H2O2 production and the decomposition of DMSO by the discharge, which were obtained using the tungsten electrodes, were compared with those determined for titanium electrodes. The electrode erosion increased significantly with an increase in the solution conductivity. A large fraction (50-70%) of the eroded tungsten electrode material was released into the solution in dissolved form as tungstate WO_4^{2-} ions. A correlation between the amount of eroded tungsten material released into the solution and the chemical effects induced by the discharge was determined. Lower yields of H2O2 and a higher degradation of DMSO by the discharge were obtained using the tungsten electrodes than were determined using titanium electrodes. Tungstate ions were shown to play a dominant role in the decomposition of H2O2, which was produced by the discharge using a tungsten electrode. The higher degradation of DMSO that was determined for tungsten was attributed to the tungstate-catalyzed oxidation of DMSO by H2O2, in addition to the oxidation of DMSO by OH radicals. Such a mechanism was supported by the detection of degradation by-products of DMSO (methanesulfonate, sulfate and dimethyl sulfone). The catalytic role of tungstate ions in the plasmachemical activity of the discharge generated using a tungsten electrode was also demonstrated on a pH-dependent decomposition of H2O2 and DMSO.

  10. Equivalent ambipolar carrier injection of electrons and holes with Au electrodes in air-stable field effect transistors

    SciTech Connect

    Kanagasekaran, Thangavel E-mail: Shimotani@m.tohoku.ac.jp Ikeda, Susumu; Kumashiro, Ryotaro; Shimotani, Hidekazu E-mail: Shimotani@m.tohoku.ac.jp Shang, Hui; Tanigaki, Katsumi E-mail: Shimotani@m.tohoku.ac.jp

    2015-07-27

    Carrier injection from Au electrodes to organic thin-film active layers can be greatly improved for both electrons and holes by nano-structural surface control of organic semiconducting thin films using long-chain aliphatic molecules on a SiO{sub 2} gate insulator. In this paper, we demonstrate a stark contrast for a 2,5-bis(4-biphenylyl)bithiophene (BP2T) active semiconducting layer grown on a modified SiO{sub 2} dielectric gate insulator between two different modifications of tetratetracontane and poly(methyl methacrylate) thin films. Important evidence that the field effect transistor (FET) characteristics are independent of electrode metals with different work functions is given by the observation of a conversion of the metal-semiconductor contact from the Schottky limit to the Bardeen limit. An air-stable light emitting FET with an Au electrode is demonstrated.

  11. End-of-life Zn-MnO2 batteries: electrode materials characterization.

    PubMed

    Cabral, Marta; Pedrosa, F; Margarido, F; Nogueira, C A

    2013-01-01

    Physical and chemical characterization of several sizes and shapes of alkaline and saline spent Zn-MnO2 batteries was carried out, aiming at contributing for a better definition of the applicable recycling processes. The characterization essays included the mass balance of the components, cathode and anode elemental analysis, the identification of zinc and manganese bearing phases and the morphology analysis of the electrode particles. The electrode materials correspond to 64-79% of the total weigh of the batteries, with the cathodes having clearly the highest contribution (usually more than 50%). The steel components, mainly from the cases, are also important (17-30%). Elemental analysis showed that the electrodes are highly concentrated in zinc (from 48-87% in anodes) and manganese (from 35-50% in cathodes). X-Ray powder diffraction allowed for identifying several phases in the electrodes, namely zinc oxide, in the anodes of all the types of saline and alkaline batteries tested, while zinc hydroxide chloride and ammine zinc chloride only appear in some types of saline batteries. The manganese found in the cathode materials is present as two main phases, MnO x Mn2O3 and ZnO x Mn2O3, the latter corroborating that zinc migration from anode to cathode occurs during the batteries lifespan. A unreacted MnO2 phase was also found presenting a low crystalline level. Leaching trials with diluted HCI solutions of alkaline and saline battery samples showed that all zinc species are reactive attaining easily over than 90% leaching yields, and about 30% of manganese, present as Mn(II/III) forms. The MnO2 phase is less reactive and requires higher temperatures to achieve a more efficient solubilization.

  12. Materials Science of Electrodes and Interfaces for High-Performance Organic Photovoltaics

    SciTech Connect

    Marks, Tobin

    2016-11-18

    The science of organic photovoltaic (OPV) cells has made dramatic advances over the past three years with power conversion efficiencies (PCEs) now reaching ~12%. The upper PCE limit of light-to-electrical power conversion for single-junction OPVs as predicted by theory is ~23%. With further basic research, the vision of such devices, composed of non-toxic, earth-abundant, readily easily processed materials replacing/supplementing current-generation inorganic solar cells may become a reality. Organic cells offer potentially low-cost, roll-to-roll manufacturable, and durable solar power for diverse in-door and out-door applications. Importantly, further gains in efficiency and durability, to that competitive with inorganic PVs, will require fundamental, understanding-based advances in transparent electrode and interfacial materials science and engineering. This team-science research effort brought together an experienced and highly collaborative interdisciplinary group with expertise in hard and soft matter materials chemistry, materials electronic structure theory, solar cell fabrication and characterization, microstructure characterization, and low temperature materials processing. We addressed in unconventional ways critical electrode-interfacial issues underlying OPV performance -- controlling band offsets between transparent electrodes and organic active-materials, addressing current loss/leakage phenomena at interfaces, and new techniques in cost-effective low temperature and large area cell fabrication. The research foci were: 1) Theory-guided design and synthesis of advanced crystalline and amorphous transparent conducting oxide (TCO) layers which test our basic understanding of TCO structure-transport property relationships, and have high conductivity, transparency, and tunable work functions but without (or minimizing) the dependence on indium. 2) Development of theory-based understanding of optimum configurations for the interfaces between oxide electrodes

  13. Identification and Mitigation of Generated Solid By-Products during Advanced Electrode Materials Processing.

    PubMed

    Tsai, Candace S J; Dysart, Arthur D; Beltz, Jay H; Pol, Vilas G

    2016-03-01

    A scalable, solid-state elevated-temperature process was developed to produce high-capacity carbonaceous electrode materials for energy storage devices via decomposition of a starch-based precursor in an inert atmosphere. In a separate study, it is shown that the fabricated carbonaceous architectures are useful as an excellent electrode material for lithium-ion, sodium-ion, and lithium-sulfur batteries. This article focuses on the study and analysis of the formed nanometer-sized by-products during the lab-scale synthesis of the carbon material. The material production process was studied in operando (that is, during the entire duration of heat treatment). The unknown downstream particles in the process exhaust were collected and characterized via aerosol and liquid suspensions, and they were quantified using direct-reading instruments for number and mass concentrations. The airborne emissions were collected using the Tsai diffusion sampler (TDS) for characterization and further analysis. Released by-product aerosols collected in a deionized (DI) water trap were analyzed, and the aerosols emitted from the post-water-suspension were collected and characterized. After long-term sampling, individual particles in the nanometer size range were observed in the exhaust aerosol with layer-structured aggregates formed on the sampling substrate. Upon the characterization of the released aerosol by-products, methods were identified to mitigate possible human and environmental exposures upon industrial implementation.

  14. Highly Ordered Mesostructured Vanadium Phosphonate toward Electrode Materials for Lithium-Ion Batteries.

    PubMed

    Mei, Peng; Pramanik, Malay; Lee, Jaewoo; Ide, Yusuke; Alothman, Zeid Abdullah; Kim, Jung Ho; Yamauchi, Yusuke

    2017-03-28

    Highly ordered mesostructured vanadium phosphonates (VP) have been synthesized in the presence of cetyltrimethylammonium bromide (CTAB) as a structure-directing agent. Nitrilotris(methylene)triphosphonic acid (NMPA) and (ammonium/sodium) metavanadate (NH4 VO3 /NaVO3 ) have been used for the construction of pore walls. The CTAB templates are removed from the materials by an extraction process without destroying the parent mesostructure. The formation mechanism for the ordered mesoporous structure and its impact on electrochemical application in lithium ion batteries (LIBs) are explained by considering the structural and electrochemical stability of the framework. The results demonstrate that the counter cations (NH4(+) /Na(+) ) of the metavanadate precursors have a crucial role in stabilizing the mesoporous structure of the mesoporous VP materials. Mesoporous VP materials with highly ordered structure have great applicability as high-performance electrode materials in LIBs due to the advantages of their large contact area with electrolyte and short transport paths for lithium ions. Mesoporous VP electrodes exhibit high reversible specific capacity with superb cycling stability (100 cycles) and excellent retention of capacity (92 %).

  15. Review of air-coupled ultrasonic materials characterization.

    PubMed

    Chimenti, D E

    2014-09-01

    This article presents a review of air-coupled ultrasonics employed in the characterization or nondestructive inspection of industrial materials. Developments in air-coupled transduction and electronics are briefly treated, although the emphasis here is on methods of characterization and inspection, and in overcoming limitations inherent in the use of such a tenuous sound coupling medium as air. The role of Lamb waves in plate characterization is covered, including the use of air-coupled acoustic beams to measure the elastic and/or viscoelastic properties of a material. Air-coupled acoustic detection, when other methods are employed to generate high-amplitude sound beams is also reviewed. Applications to civil engineering, acoustic tomography, and the characterization of both paper and wood are dealt with here. A brief summary of developments in air-coupled acoustic arrays and the application of air-coupled methods in nonlinear ultrasonics complete the review. In particular, the work of Professor Bernard Hosten and his collaborators at Bordeaux is carefully examined.

  16. Study on electrical characteristics of barrier-free atmospheric air diffuse discharge generated by nanosecond pulses and long wire electrodes

    SciTech Connect

    Li, Lee Liu, Yun-Long; Teng, Yun; Liu, Lun; Pan, Yuan

    2014-07-15

    In room-temperature atmospheric air, the large-scale diffuse plasmas can be generated via high-voltage nanosecond pulses with short rise-time and wire electrodes. Diffuse discharge with the wire electrode length up to 110.0 cm and the discharge spacing of several centimeters has been investigated in this paper. Electrical characteristics of diffuse discharge have been analyzed by their optical photographs and measuring of the voltage and current waveforms. Experimental results show the electrode spacing, and the length of wire electrodes can influence the intensity and mode transition of diffuse discharge. The characteristic of current waveforms is that there are several current oscillation peaks at the time of applied pulsed voltage peak, and at the tail of applied pulse, the conduction current component will compensate the displacement one so that the measured current is unidirectional in diffuse discharge mode. The transition from diffuse discharge to arc discharge is always with the increasing of conduction current density. As for nanosecond pulses with long tail, the long wire electrodes are help for generating non-equilibrium diffuse plasmas.

  17. Integration of microchip electrophoresis with electrochemical detection using an epoxy-based molding method to embed multiple electrode materials.

    PubMed

    Johnson, Alicia S; Selimovic, Asmira; Martin, R Scott

    2011-11-01

    This paper describes the use of epoxy-encapsulated electrodes to integrate microchip-based electrophoresis with electrochemical detection. Devices with various electrode combinations can easily be developed. This includes a palladium decoupler with a downstream working electrode material of either gold, mercury/gold, platinum, glassy carbon, or a carbon fiber bundle. Additional device components such as the platinum wires for the electrophoresis separation and the counter electrode for detection can also be integrated into the epoxy base. The effect of the decoupler configuration was studied in terms of the separation performance, detector noise, and the ability to analyze samples of a high ionic strength. The ability of both glassy carbon and carbon fiber bundle electrodes to analyze a complex mixture was demonstrated. It was also shown that a PDMS-based valving microchip can be used along with the epoxy-embedded electrodes to integrate microdialysis sampling with microchip electrophoresis and electrochemical detection, with the microdialysis tubing also being embedded in the epoxy substrate. This approach enables one to vary the detection electrode material as desired in a manner where the electrodes can be polished and modified as is done with electrochemical flow cells used in liquid chromatography.

  18. Transitions from near-surface to interior redox upon lithiation in conversion electrode materials

    SciTech Connect

    He, Kai; Xin, Huolin L.; Zhao, Kejie; Yu, Xiqian; Norlund, Dennis; Weng, Tsu-Chien; Li, Jing; Jiang, Yi; Cadigan, Christopher A.; Richards, Ryan M.; Doeff, Marca M.; Yang, Xiao-Qing; Stach, Eric A.; Li, Ju; Lin, Feng; Su, Dong

    2015-01-29

    Nanoparticle electrodes in lithium-ion batteries have both near-surface and interior contributions to their redox capacity, each with distinct rate capabilities. Using combined electron microscopy, synchrotron X-ray methods and ab initio calculations, we have investigated the lithiation pathways that occur in NiO electrodes. We find that the near-surface electroactive (Ni²⁺→Ni⁰) sites saturated very quickly, and then encounter unexpected difficulty in propagating the phase transition into the electrode (referred to as a “shrinking-core” mode). However, the interior capacity for Ni²⁺→Ni⁰ can be accessed efficiently following the nucleation of lithiation “fingers” which propagate into the sample bulk, but only after a certain incubation time. Our microstructural observations of the transition from a slow shrinking-core mode to a faster lithiation finger mode corroborate with synchrotron characterization of large-format batteries, and can be rationalized by stress effects on transport at high-rate discharge. The finite incubation time of the lithiation fingers sets the intrinsic limitation for the rate capability (and thus the power) of NiO for electrochemical energy storage devices. The present work unravels the link between the nanoscale reaction pathways and the C-rate-dependent capacity loss, and provides guidance for the further design of battery materials that favors high C-rate charging.

  19. Transitions from near-surface to interior redox upon lithiation in conversion electrode materials

    DOE PAGES

    He, Kai; Xin, Huolin L.; Zhao, Kejie; ...

    2015-01-29

    Nanoparticle electrodes in lithium-ion batteries have both near-surface and interior contributions to their redox capacity, each with distinct rate capabilities. Using combined electron microscopy, synchrotron X-ray methods and ab initio calculations, we have investigated the lithiation pathways that occur in NiO electrodes. We find that the near-surface electroactive (Ni²⁺→Ni⁰) sites saturated very quickly, and then encounter unexpected difficulty in propagating the phase transition into the electrode (referred to as a “shrinking-core” mode). However, the interior capacity for Ni²⁺→Ni⁰ can be accessed efficiently following the nucleation of lithiation “fingers” which propagate into the sample bulk, but only after a certain incubationmore » time. Our microstructural observations of the transition from a slow shrinking-core mode to a faster lithiation finger mode corroborate with synchrotron characterization of large-format batteries, and can be rationalized by stress effects on transport at high-rate discharge. The finite incubation time of the lithiation fingers sets the intrinsic limitation for the rate capability (and thus the power) of NiO for electrochemical energy storage devices. The present work unravels the link between the nanoscale reaction pathways and the C-rate-dependent capacity loss, and provides guidance for the further design of battery materials that favors high C-rate charging.« less

  20. Electrode including porous particles with embedded active material for use in a secondary electrochemical cell

    DOEpatents

    Vissers, Donald R.; Nelson, Paul A.; Kaun, Thomas D.; Tomczuk, Zygmunt

    1978-04-25

    Particles of carbonaceous matrices containing embedded electrode active material are prepared for vibratory loading within a porous electrically conductive substrate. In preparing the particles, active materials such as metal chalcogenides, solid alloys of alkali or alkaline earth metals along with other metals and their oxides in powdered or particulate form are blended with a thermosetting resin and particles of a volatile to form a paste mixture. The paste is heated to a temperature at which the volatile transforms into vapor to impart porosity at about the same time as the resin begins to cure into a rigid, solid structure. The solid structure is then comminuted into porous, carbonaceous particles with the embedded active material.

  1. Method of preparing porous, active material for use in electrodes of secondary electrochemical cells

    DOEpatents

    Vissers, Donald R.; Nelson, Paul A.; Kaun, Thomas D.; Tomczuk, Zygmunt

    1977-01-01

    Particles of carbonaceous matrices containing embedded electrode active material are prepared for vibratory loading within a porous electrically conductive substrate. In preparing the particles, active materials such as metal chalcogenides, solid alloys of alkali or alkaline earth metals along with other metals and their oxides in powdered or particulate form are blended with a thermosetting resin and particles of a volatile to form a paste mixture. The paste is heated to a temperature at which the volatile transforms into vapor to impart porosity at about the same time as the resin begins to cure into a rigid, solid structure.The solid structure is then comminuted into porous, carbonaceous particles with the embedded active material.

  2. Penternary chalcogenides nanocrystals as catalytic materials for efficient counter electrodes in dye-synthesized solar cells

    PubMed Central

    Özel, Faruk; Sarılmaz, Adem; İstanbullu, Bilal; Aljabour, Abdalaziz; Kuş, Mahmut; Sönmezoğlu, Savaş

    2016-01-01

    The penternary chalcogenides Cu2CoSn(SeS)4 and Cu2ZnSn(SeS)4 were successfully synthesized by hot-injection method, and employed as a catalytic materials for efficient counter electrodes in dye-synthesized solar cells (DSSCs). The structural, compositional, morphological and optical properties of these pentenary semiconductors were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive spectrometer (EDS) and ultraviolet-visible (UV–Vis) spectroscopy. The Cu2CoSn(SeS)4 and Cu2ZnSn(SeS)4 nanocrystals had a single crystalline, kesterite phase, adequate stoichiometric ratio, 18–25 nm particle sizes which are forming nanospheres, and band gap energy of 1.18 and 1.45 eV, respectively. Furthermore, the electrochemical impedance spectroscopy and cyclic voltammograms indicated that Cu2CoSn(SeS)4 nanocrystals as counter electrodes exhibited better electrocatalytic activity for the reduction of iodine/iodide electrolyte than that of Cu2ZnSn(SeS)4 nanocrystals and conventional platinum (Pt). The photovoltaic results demonstrated that DSSC with a Cu2CoSn(SeS)4 nanocrystals-based counter electrode achieved the best efficiency of 6.47%, which is higher than the same photoanode employing a Cu2ZnSn(SeS)4 nanocrystals (3.18%) and Pt (5.41%) counter electrodes. These promising results highlight the potential application of penternary chalcogen Cu2CoSn(SeS)4 nanocrystals in low-cost, high-efficiency, Pt-free DSSCs. PMID:27380957

  3. Penternary chalcogenides nanocrystals as catalytic materials for efficient counter electrodes in dye-synthesized solar cells

    NASA Astrophysics Data System (ADS)

    Özel, Faruk; Sarılmaz, Adem; Istanbullu, Bilal; Aljabour, Abdalaziz; Kuş, Mahmut; Sönmezoğlu, Savaş

    2016-07-01

    The penternary chalcogenides Cu2CoSn(SeS)4 and Cu2ZnSn(SeS)4 were successfully synthesized by hot-injection method, and employed as a catalytic materials for efficient counter electrodes in dye-synthesized solar cells (DSSCs). The structural, compositional, morphological and optical properties of these pentenary semiconductors were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive spectrometer (EDS) and ultraviolet-visible (UV–Vis) spectroscopy. The Cu2CoSn(SeS)4 and Cu2ZnSn(SeS)4 nanocrystals had a single crystalline, kesterite phase, adequate stoichiometric ratio, 18–25 nm particle sizes which are forming nanospheres, and band gap energy of 1.18 and 1.45 eV, respectively. Furthermore, the electrochemical impedance spectroscopy and cyclic voltammograms indicated that Cu2CoSn(SeS)4 nanocrystals as counter electrodes exhibited better electrocatalytic activity for the reduction of iodine/iodide electrolyte than that of Cu2ZnSn(SeS)4 nanocrystals and conventional platinum (Pt). The photovoltaic results demonstrated that DSSC with a Cu2CoSn(SeS)4 nanocrystals-based counter electrode achieved the best efficiency of 6.47%, which is higher than the same photoanode employing a Cu2ZnSn(SeS)4 nanocrystals (3.18%) and Pt (5.41%) counter electrodes. These promising results highlight the potential application of penternary chalcogen Cu2CoSn(SeS)4 nanocrystals in low-cost, high-efficiency, Pt-free DSSCs.

  4. Physics of electron and lithium-ion transport in electrode materials for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Musheng, Wu; Bo, Xu; Chuying, Ouyang

    2016-01-01

    The physics of ionic and electrical conduction at electrode materials of lithium-ion batteries (LIBs) are briefly summarized here, besides, we review the current research on ionic and electrical conduction in electrode material incorporating experimental and simulation studies. Commercial LIBs have been widely used in portable electronic devices and are now developed for large-scale applications in hybrid electric vehicles (HEV) and stationary distributed power stations. However, due to the physical limits of the materials, the overall performance of today’s LIBs does not meet all the requirements for future applications, and the transport problem has been one of the main barriers to further improvement. The electron and Li-ion transport behaviors are important in determining the rate capacity of LIBs. Project supported by the National High Technology Research and Development Program of China (Grant No. 2015AA034201), the National Natural Science Foundation of China (Grant Nos. 11234013 and 11264014), the Natural Science Foundation of Jiangxi Province, China (Grant Nos. 20133ACB21010 and 20142BAB212002), and the Foundation of Jiangxi Education Committee, China (Grant Nos. GJJ14254 and KJLD14024). C. Y. Ouyang is also supported by the “Gan-po talent 555” Project of Jiangxi Province, China.

  5. Conductive Polymer-Coated VS4 Submicrospheres As Advanced Electrode Materials in Lithium-Ion Batteries.

    PubMed

    Zhou, Yanli; Li, Yanlu; Yang, Jing; Tian, Jian; Xu, Huayun; Yang, Jian; Fan, Weiliu

    2016-07-27

    VS4 as an electrode material in lithium-ion batteries holds intriguing features like high content of sulfur and one-dimensional structure, inspiring the exploration in this field. Herein, VS4 submicrospheres have been synthesized via a simple solvothermal reaction. However, they quickly degrade upon cycling as an anode material in lithium-ion batteries. So, three conductive polymers, polythiophene (PEDOT), polypyrrole (PPY), and polyaniline (PANI), are coated on the surface to improve the electron conductivity, suppress the diffusion of polysulfides, and modify the interface between electrode/electrolyte. PANI is the best in the polymers. It improves the Coulombic efficiency to 86% for the first cycle and keeps the specific capacity at 755 mAh g(-1) after 50 cycles, higher than the cases of naked VS4 (100 mAh g(-1)), VS4@PEDOT (318 mAh g(-1)), and VS4@PPY (448 mAh g(-1)). The good performances could be attributed to the improved charge-transfer kinetics and the strong interaction between PANI and VS4 supported by theoretical simulation. The discharge voltage ∼2.0 V makes them promising cathode materials.

  6. High rate, long cycle life battery electrode materials with an open framework structure

    DOEpatents

    Wessells, Colin; Huggins, Robert; Cui, Yi; Pasta, Mauro

    2015-02-10

    A battery includes a cathode, an anode, and an aqueous electrolyte disposed between the cathode and the anode and including a cation A. At least one of the cathode and the anode includes an electrode material having an open framework crystal structure into which the cation A is reversibly inserted during operation of the battery. The battery has a reference specific capacity when cycled at a reference rate, and at least 75% of the reference specific capacity is retained when the battery is cycled at 10 times the reference rate.

  7. Synthesis and characterization of high performance electrode materials for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Hong, Jian

    Lithium-ion batteries have revolutionized portable electronics. Electrode reactions in these electrochemical systems are based on reversible intercalation of Li+ ions into the host electrode material with a concomitant addition/removal of electrons into the host. If such batteries are to find a wider market such as the automotive industry, less expensive and higher capacity electrode materials will be required. The olivine phase lithium iron phosphate has attracted the most attention because of its low cost and safety (high thermal and chemical stability). However, it is an intriguing fundamental problem to understand the fast electrochemical response from the poorly electronic conducting two-phase LiFePO4/FePO 4 system. This thesis focuses on determining the rate-limit step of LiFePO4. First, a LiFePO4 material, with vanadium substituting on the P-site, was synthesized, and found that the crystal structure change may cause high lithium diffusivity. Since an accurate Li diffusion coefficient cannot be measured by traditional electrochemical method in a three-electrode cell due to the phase transformation during measurement, a new method to measure the intrinsic electronic and ionic conductivity of mixed conductive LiFePO 4 was developed. This was based on the conductivity measurements of mixed conductive solid electrolyte using electrochemical impedance spectroscopy (EIS) and blocking electrode. The effects of ionic/electronic conductivity and phase transformation on the rate performance of LiFePO4 were also first investigated by EIS and other electrochemical technologies. Based on the above fundamental kinetics studies, an optimized LiFePO4 was used as a target to deposit 1mum LiFePO4 thin film at Oak Ridge National Laboratory using radio frequency (RF) magnetron sputtering. Similar to the carbon coated LiFePO4 powder electrode, the carbon-contained RF LiFePO4 film with no preferential orientation showed excellent capacity and rate capability both at 25°C and -20

  8. Metal-Air Batteries

    SciTech Connect

    Zhang, Jiguang; Bruce, Peter G.; Zhang, Gregory

    2011-08-01

    Metal-air batteries have much higher specific energies than most currently available primary and rechargeable batteries. Recent advances in electrode materials and electrolytes, as well as new designs on metal-air batteries, have attracted intensive effort in recent years, especially in the development of lithium-air batteries. The general principle in metal-air batteries will be reviewed in this chapter. The materials, preparation methods, and performances of metal-air batteries will be discussed. Two main metal-air batteries, Zn-air and Li-air batteries will be discussed in detail. Other type of metal-air batteries will also be described.

  9. Materials, design and processing of air encapsulated MEMS packaging

    NASA Astrophysics Data System (ADS)

    Fritz, Nathan T.

    This work uses a three-dimensional air cavity technology to improve the fabrication, and functionality of microelectronics devices, performance of on-board transmission lines, and packaging of micro-electromechanical systems (MEMS). The air cavity process makes use of the decomposition of a patterned sacrificial polymer followed by the diffusion of its by-products through a curing polymer overcoat to obtain the embedded air structure. Applications and research of air cavities have focused on simple designs that concentrate on the size and functionality of the particular device. However, a lack of guidelines for fabrication, materials used, and structural design has led to mechanical stability issues and processing refinements. This work investigates improved air gap cavities for use in MEMS packaging processes, resulting in fewer fabrication flaws and lower cost. The identification of new materials, such as novel photo-definable organic/inorganic hybrid polymers, was studied for increased strength and rigidity due to their glass-like structure. A novel epoxy polyhedral oligomeric silsesquioxane (POSS) material was investigated and characterized for use as a photodefineable, permanent dielectrics with improved mechanical properties. The POSS material improved the air gap fabrication because it served as a high-selectivity etch mask for patterning sacrificial materials as well as a cavity overcoat material with improved rigidity. An investigation of overcoat thickness and decomposition kinetics provided a fundamental understanding of the properties that impart mechanical stability to cavities of different shape and volume. Metallization of the cavities was investigated so as to provide hermetic sealing and improved cavity strength. The improved air cavity, wafer-level packages were tested using resonator-type devices and chip-level lead frame packaging. The air cavity package was molded under traditional lead frame molding pressures and tested for mechanical

  10. CLASSIFICATION OF MATERIALS AS POTENTIAL SOURCES OF INDOOR AIR POLLUTION

    EPA Science Inventory

    The report gives a complete classification of all materials used in the construction of, or brought inside, homes and office buildings. n the classification tables Presented in the report, shaded entries are potential Sources of indoor air emissions. he classification system is b...

  11. Improved Manufacturing Performance of Screen Printed Carbon Electrodes through Material Formulation

    PubMed Central

    Jewell, Eifion; Philip, Bruce; Greenwood, Peter

    2016-01-01

    Printed carbon graphite materials are the primary common component in the majority of screen printed sensors. Screen printing allows a scalable manufacturing solution, accelerating the means by which novel sensing materials can make the transition from laboratory material to commercial product. A common bottleneck in any thick film printing process is the controlled drying of the carbon paste material. A study has been undertaken which examines the interaction between material solvent, printed film conductivity and process consistency. The study illustrates that it is possible to reduce the solvent boiling point to significantly increase process productivity while maintaining process consistency. The lower boiling point solvent also has a beneficial effect on the conductivity of the film, reducing the sheet resistance. It is proposed that this is a result of greater film stressing increasing charge percolation through greater inter particle contact. Simulations of material performance and drying illustrate that a multi layered printing provides a more time efficient manufacturing method. The findings have implications for the volume manufacturing of the carbon sensor electrodes but also have implications for other applications where conductive carbon is used, such as electrical circuits and photovoltaic devices. PMID:27355967

  12. Improved Manufacturing Performance of Screen Printed Carbon Electrodes through Material Formulation.

    PubMed

    Jewell, Eifion; Philip, Bruce; Greenwood, Peter

    2016-06-27

    Printed carbon graphite materials are the primary common component in the majority of screen printed sensors. Screen printing allows a scalable manufacturing solution, accelerating the means by which novel sensing materials can make the transition from laboratory material to commercial product. A common bottleneck in any thick film printing process is the controlled drying of the carbon paste material. A study has been undertaken which examines the interaction between material solvent, printed film conductivity and process consistency. The study illustrates that it is possible to reduce the solvent boiling point to significantly increase process productivity while maintaining process consistency. The lower boiling point solvent also has a beneficial effect on the conductivity of the film, reducing the sheet resistance. It is proposed that this is a result of greater film stressing increasing charge percolation through greater inter particle contact. Simulations of material performance and drying illustrate that a multi layered printing provides a more time efficient manufacturing method. The findings have implications for the volume manufacturing of the carbon sensor electrodes but also have implications for other applications where conductive carbon is used, such as electrical circuits and photovoltaic devices.

  13. Electrode materials: a challenge for the exploitation of protonic solid oxide fuel cells

    PubMed Central

    Fabbri, Emiliana; Pergolesi, Daniele; Traversa, Enrico

    2010-01-01

    High temperature proton conductor (HTPC) oxides are attracting extensive attention as electrolyte materials alternative to oxygen-ion conductors for use in solid oxide fuel cells (SOFCs) operating at intermediate temperatures (400–700 °C). The need to lower the operating temperature is dictated by cost reduction for SOFC pervasive use. The major stake for the deployment of this technology is the availability of electrodes able to limit polarization losses at the reduced operation temperature. This review aims to comprehensively describe the state-of-the-art anode and cathode materials that have so far been tested with HTPC oxide electrolytes, offering guidelines and possible strategies to speed up the development of protonic SOFCs. PMID:27877342

  14. TOPICAL REVIEW: Electrode materials: a challenge for the exploitation of protonic solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Fabbri, Emiliana; Pergolesi, Daniele; Traversa, Enrico

    2010-08-01

    High temperature proton conductor (HTPC) oxides are attracting extensive attention as electrolyte materials alternative to oxygen-ion conductors for use in solid oxide fuel cells (SOFCs) operating at intermediate temperatures (400-700 °C). The need to lower the operating temperature is dictated by cost reduction for SOFC pervasive use. The major stake for the deployment of this technology is the availability of electrodes able to limit polarization losses at the reduced operation temperature. This review aims to comprehensively describe the state-of-the-art anode and cathode materials that have so far been tested with HTPC oxide electrolytes, offering guidelines and possible strategies to speed up the development of protonic SOFCs.

  15. Experimental and theoretical investigations of functionalized boron nitride as electrode materials for Li-ion batteries

    SciTech Connect

    Zhang, Fan; Nemeth, Karoly; Bareno, Javier; Dogan, Fulya; Bloom, Ira D.; Shaw, Leon L.

    2016-03-03

    The feasibility of synthesizing functionalized h-BN (FBN) via the reaction between molten LiOH and solid h-BN is studied for the first time and its first ever application as an electrode material in Li-ion batteries is evaluated. Density functional theory (DFT) calculations are performed to provide mechanistic understanding of the possible electrochemical reactions derived from the FBN. Various materials characterizations reveal that the melt-solid reaction can lead to exfoliation and functionalization of h-BN simultaneously, while electrochemical analysis proves that the FBN can reversibly store charges through surface redox reactions with good cycle stability and coulombic efficiency. As a result, the DFT calculations have provided physical insights into the observed electrochemical properties derived from the FBN.

  16. Experimental and theoretical investigations of functionalized boron nitride as electrode materials for Li-ion batteries

    DOE PAGES

    Zhang, Fan; Nemeth, Karoly; Bareno, Javier; ...

    2016-03-03

    The feasibility of synthesizing functionalized h-BN (FBN) via the reaction between molten LiOH and solid h-BN is studied for the first time and its first ever application as an electrode material in Li-ion batteries is evaluated. Density functional theory (DFT) calculations are performed to provide mechanistic understanding of the possible electrochemical reactions derived from the FBN. Various materials characterizations reveal that the melt-solid reaction can lead to exfoliation and functionalization of h-BN simultaneously, while electrochemical analysis proves that the FBN can reversibly store charges through surface redox reactions with good cycle stability and coulombic efficiency. As a result, the DFTmore » calculations have provided physical insights into the observed electrochemical properties derived from the FBN.« less

  17. Photoconductivity of high voltage space insulating materials: Measurements with metal electrodes

    NASA Technical Reports Server (NTRS)

    Coffey, H. T.; Nanevicz, J. E.

    1975-01-01

    The electrical conductivities of high voltage insulating materials were measured in the dark and under various intensities of illumination. The materials investigated included FEP Teflon, Kapton-H, fused quartz, and parylene. Conductivities were determined as functions of temperature between 22 and 100 C and light intensity between 0 and 2.5 kW/m2. The thickness dependence of the conductivity was determined for Teflon and Kapton, and the influence of spectral wavelengths on the conductivity was determined in several cases. All measurements were made in a vacuum to simulate a space environment, and all samples had metallic electrodes. The conductivity of Kapton was permanently increased by exposure to light; changes as great as five orders of magnitude were observed after six hours of illumination.

  18. Characterisation of porous carbon electrode materials used in proton exchange membrane fuel cells via gas adsorption

    NASA Astrophysics Data System (ADS)

    Watt-Smith, M. J.; Rigby, S. P.; Ralph, T. R.; Walsh, F. C.

    Porous carbon materials are typically used in both the substrate (typically carbon paper) and the electrocatalyst supports (often platinised carbon) within proton exchange membrane fuel cells. Gravimetric nitrogen adsorption has been studied at a carbon paper substrate, two different Pt-loaded carbon paper electrodes and three particulate carbon blacks. N 2 BET surface areas and surface fractal dimensions were determined using the fractal BET and Frenkel-Halsey-Hill models for all but one of the materials studied. The fractal dimensions of the carbon blacks obtained from gas adsorption were compared with those obtained independently by small angle X-ray scattering and showed good agreement. Density functional theory was used to characterise one of the carbon blacks, as the standard BET model was not applicable.

  19. Secondary Electron Emission from Dielectric Materials of a Hall Thruster with Segmented Electrodes

    SciTech Connect

    A. Dunaevsky; Y. Raitses; N.J. Fisch

    2003-02-12

    The discharge parameters in Hall thrusters depend strongly on the yield of secondary electron emission from channel walls. Comparative measurements of the yield of secondary electron emission at low energies of primary electrons were performed for several dielectric materials used in Hall thrusters with segmented electrodes. The measurements showed that at low energies of primary electrons the actual energetic dependencies of the total yield of secondary electron emission could differ from fits, which are usually used in theoretical models. The observed differences might be caused by electron backscattering, which is dominant at lower energies and depends strongly on surface properties. Fits based on power or linear laws are relevant at higher energies of primary electrons, where the bulk material properties play a decisive role.

  20. Studies on two classes of positive electrode materials for lithium-ion batteries

    SciTech Connect

    Wilcox, James Douglas

    2008-12-01

    The development of advanced lithium-ion batteries is key to the success of many technologies, and in particular, hybrid electric vehicles. In addition to finding materials with higher energy and power densities, improvements in other factors such as cost, toxicity, lifetime, and safety are also required. Lithium transition metal oxide and LiFePO4/C composite materials offer several distinct advantages in achieving many of these goals and are the focus of this report. Two series of layered lithium transition metal oxides, namely LiNi1/3Co1/3-yMyMn1/3O2 (M=Al, Co, Fe, Ti) and LiNi0.4Co0.2-yMyMn0.4O2 (M = Al, Co, Fe), have been synthesized. The effect of substitution on the crystal structure is related to shifts in transport properties and ultimately to the electrochemical performance. Partial aluminum substitution creates a high-rate positive electrode material capable of delivering twice the discharge capacity of unsubstituted materials. Iron substituted materials suffer from limited electrochemical performance and poor cycling stability due to the degradation of the layered structure. Titanium substitution creates a very high rate positive electrode material due to a decrease in the anti-site defect concentration. LiFePO4 is a very promising electrode material but suffers from poor electronic and ionic conductivity. To overcome this, two new techniques have been developed to synthesize high performance LiFePO4/C composite materials. The use of graphitization catalysts in conjunction with pyromellitic acid leads to a highly graphitic carbon coating on the surface of LiFePO4 particles. Under the proper conditions, the room temperature electronic conductivity can be improved by nearly five orders of magnitude over untreated materials. Using Raman spectroscopy, the improvement in conductivity and rate performance of

  1. Calcium phosphates deposited on titanium electrode surface--part 1: Effect of the electrode polarity and oxide film on the deposited materials.

    PubMed

    Okawa, Seigo; Watanabe, Kouichi; Kanatani, Mitsugu

    2013-01-01

    We report experimental results about the effect of polarity of electrode and anodized titanium oxide film on the deposited materials by electrolysis of an acidic calcium phosphate solution. Mirror-polished titanium and anodized titanium were used as anode or cathode, and a Pt plate was used as a counter electrode. The load voltage was held constant at 20 VDC. No deposited materials were found on the anode surface. On the other hand, dicalcium phosphate dihydrate (DCPD) was deposited on the cathode surface at the beginning of the electrolysis. After the electrolysis time 600 s, the non-stoichiometric hydroxyapatite (HAp) with several hundred nanometers was formed on the specimen surface. Based on X-ray photoelectron spectroscopy data, the anodized oxide film contained both P(5+) and P(3+) ions. This characteristic of the oxide film and the electrolysis conditions were related to the behavior of the deposition of ultra fine HAp with high crystallinity.

  2. Time-lag properties of corona streamer discharges between impulse sphere and dc needle electrodes under atmospheric air conditions.

    PubMed

    Okano, Daisuke

    2013-02-01

    In this study of corona streamer discharges from an impulse generator using a dc power supply, the relationship of the discharge time-lag with the dc bias voltage between the sphere-to-needle electrodes under atmospheric conditions is investigated. Devices utilizing corona discharges have been used to purify air or water, destroy bacteria, and to remove undesirable substances, and in order to achieve fast response times and high power efficiencies in such devices, it is important to minimize the time-lag of the corona discharge. Our experimental results show that (a) the discharge path of a negatively biased needle electrode will be straighter than that of a positively biased needle and (b) the discharge threshold voltage in both the positive and the negative needle electrodes is nearly equal to 33 kV. By expressing the discharge voltage as a power function of time-lag, the extent of corona generation can be quantitatively specified using the exponent of this power function. The observed behavior of a corona streamer discharge between the negative spherical and the positive needle electrodes indicates that the largest power exponent is associated with the shortest time-lag, owing to the reduction in the statistical time-lag in the absence of a formative time-lag.

  3. Time-lag properties of corona streamer discharges between impulse sphere and dc needle electrodes under atmospheric air conditions

    NASA Astrophysics Data System (ADS)

    Okano, Daisuke

    2013-02-01

    In this study of corona streamer discharges from an impulse generator using a dc power supply, the relationship of the discharge time-lag with the dc bias voltage between the sphere-to-needle electrodes under atmospheric conditions is investigated. Devices utilizing corona discharges have been used to purify air or water, destroy bacteria, and to remove undesirable substances, and in order to achieve fast response times and high power efficiencies in such devices, it is important to minimize the time-lag of the corona discharge. Our experimental results show that (a) the discharge path of a negatively biased needle electrode will be straighter than that of a positively biased needle and (b) the discharge threshold voltage in both the positive and the negative needle electrodes is nearly equal to 33 kV. By expressing the discharge voltage as a power function of time-lag, the extent of corona generation can be quantitatively specified using the exponent of this power function. The observed behavior of a corona streamer discharge between the negative spherical and the positive needle electrodes indicates that the largest power exponent is associated with the shortest time-lag, owing to the reduction in the statistical time-lag in the absence of a formative time-lag.

  4. Development of Novel Metal Hydride-Carbon Nanomaterial Based Nanocomposites as Anode Electrode Materials for Lithium Ion Battery

    DTIC Science & Technology

    2014-06-30

    and pG-f-MWNT after the first cycle. These may be attributed to the lithium ion consumption during the electrolyte decomposition and formation of... solid electrolyte interface film around the electrodes with large surface areas.25 After the 30th and the 100th cycle SEG yielded a reversible discharge...anode electrode materials for Lithium ion battery Objectives:- The aim of this study is to develop metal hydride–carbon nanomaterial based

  5. Materials issues in solar detoxification of air and water

    NASA Astrophysics Data System (ADS)

    Blake, Daniel M.; Magrini-Bair, Kim; Wolfrum, Edward; May, E. K.

    1997-10-01

    The technical feasibility of photocatalytic oxidation and reduction technology for the removal of hazardous chemicals or micro-organisms from contaminated water and air is well established. The heterogeneous process based on titanium dioxide photocatalysts is the most developed but homogeneous systems are also under development. Treatment equipment using fluorescent lamps as the photon source and supported heterogeneous photocatalysts are commercially available and one-sun and parabolic solar reactor designs have been demonstrated. Cost and performance of the solar processes have not yet reached levels that make them attractive relative to conventional alternatives. Cost reductions and increased performance require improvements in optical materials for reactors, reactor/collector design and materials of construction, durable catalyst materials and support structures, and significant improvement in the utilization of the solar spectrum in the photochemical processes. The current state of the art for solar reactors for treatment of contaminated air and water are presented and the opportunities for improvement are identified.

  6. Niobium doped lanthanum calcium ferrite perovskite as a novel electrode material for symmetrical solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Kong, Xiaowei; Zhou, Xiaoliang; Tian, Yu; Wu, Xiaoyan; Zhang, Jun; Zuo, Wei

    2016-09-01

    Development of cost-effective and efficient electrochemical catalysts for the fuel cells electrode is of prime importance to emerging renewable energy technologies. Here, we report for the first time the novel La0.9Ca0.1Fe0.9Nb0.1O3-δ (LCFNb) perovskite with good potentiality for the electrode material of the symmetrical solid oxide fuel cells (SSOFC). The Sc0.2Zr0.8O2-δ (SSZ) electrolyte supported symmetrical cells with impregnated LCFNb and LCFNb/SDC (Ce0.8Sm0.2O2-δ) electrodes achieve relatively high power outputs with maximum power densities (MPDs) reaching up to 392 and 528.6 mW cm-2 at 850 °C in dry H2, respectively, indicating the excellent electro-catalytic activity of LCFNb towards both hydrogen oxidation and oxygen reduction. Besides, the MPDs of the symmetrical cells with LCFNb/SDC composite electrodes in CO and syngas (CO: H2 = 1:1) are almost identical to those in H2, implying that LCFNb material has similar catalytic activities to carbon monoxide compared with hydrogen. High durability in both H2, CO and syngas during the short term stability tests for 50 h are also obtained, showing desirable structure stability, and carbon deposition resistance of LCFNb based electrodes. The present results indicate that the LCFNb perovskite with remarkable cell performance is a promising electrode material for symmetrical SOFCs.

  7. Influence of carbon electrode material on energy recovery from winery wastewater using a dual-chamber microbial fuel cell.

    PubMed

    Penteado, Eduardo D; Fernandez-Marchante, Carmen M; Zaiat, Marcelo; Gonzalez, Ernesto R; Rodrigo, Manuel A

    2016-09-12

    The aim of this work was to evaluate three carbon materials as anodes in microbial fuel cells (MFCs), clarifying their influence on the generation of electricity and on the treatability of winery wastewater, a highly organic-loaded waste. The electrode materials tested were carbon felt, carbon cloth and carbon paper and they were used at the same time as anode and cathode in the tests. The MFC equipped with carbon felt reached the highest voltage and power (72 mV and 420 mW m(-2), respectively), while the lowest values were observed when carbon paper was used as electrode (0.2 mV and 8.37·10(-6) mW m(-2), respectively). Chemical oxygen demand (COD) removal from the wastewater was observed to depend on the electrode material, as well. When carbon felt was used, the MFC showed the highest average organic matter consumption rate (650 mg COD L(-1) d(-1)), whereas by using carbon paper the rate decreased to 270 mg COD L(-1) d(-1). Therefore, both electricity generation and organic matter removal are strongly related not to the chemical composition of the electrode (which was graphite carbon in the three electrodes), but to its surface features and, consequently, to the amount of biomass adhered to the electrode surface.

  8. Atomic-scale structure evolution in a quasi-equilibrated electrochemical process of electrode materials for rechargeable batteries.

    PubMed

    Gu, Lin; Xiao, Dongdong; Hu, Yong-Sheng; Li, Hong; Ikuhara, Yuichi

    2015-04-01

    Lithium-ion batteries have proven to be extremely attractive candidates for applications in portable electronics, electric vehicles, and smart grid in terms of energy density, power density, and service life. Further performance optimization to satisfy ever-increasing demands on energy storage of such applications is highly desired. In most of cases, the kinetics and stability of electrode materials are strongly correlated to the transport and storage behaviors of lithium ions in the lattice of the host. Therefore, information about structural evolution of electrode materials at an atomic scale is always helpful to explain the electrochemical performances of batteries at a macroscale. The annular-bright-field (ABF) imaging in aberration-corrected scanning transmission electron microscopy (STEM) allows simultaneous imaging of light and heavy elements, providing an unprecedented opportunity to probe the nearly equilibrated local structure of electrode materials after electrochemical cycling at atomic resolution. Recent progress toward unraveling the atomic-scale structure of selected electrode materials with different charge and/or discharge state to extend the current understanding of electrochemical reaction mechanism with the ABF and high angle annular dark field STEM imaging is presented here. Future research on the relationship between atomic-level structure evolution and microscopic reaction mechanisms of electrode materials for rechargeable batteries is envisaged.

  9. Lactose electroisomerization into lactulose: effect of the electrode material, active membrane surface area-to-electrode surface area ratio, and interelectrode-membrane distance.

    PubMed

    Aït-Aissa, Amara; Aïder, Mohammed

    2014-01-01

    The aim of the present work was to study and develop an innovative, clean, and environmentally friendly process for lactulose synthesis by electroactivation of lactose. In this work, the electrode material (type 304 stainless steel, titanium, and copper), dimensionless interelectrode-membrane distance at the cathodic compartment (0.36, 0.68, and 1), and the membrane:electrode surface area ratio (0.23, 0.06, and 0.015) were considered to be the factors that could affect the kinetic conversion of lactose into lactulose. The reactions were conducted under an initial lactose concentration of 0.15mol/L at 10°C, Froude number (mixing speed) of 2.05×10(-2), and electric current intensity of 300mA for 30min. The highest lactulose formation yield of 32.50% (0.05mol/L) was obtained by using a copper electrode, interelectrode-membrane distance of 0.36, and membrane:electrode surface area ratio of 0.23. The 2-parameter Langmuir, Freundlich, and Temkin isotherm models were used for the prediction of the lactose isomerization kinetics as well as the 3-parameter Langmuir-Freundlich isotherm model. It was shown that the lactose isomerization kinetics into lactulose followed the Temkin and Langmuir-Freundlich models with coefficients of determination of 0.99 and 0.90 and a relative error of 1.42 to 1.56% and 4.27 to 4.37%, respectively.

  10. Supercapacitor electrode materials with hierarchically structured pores from carbonization of MWCNTs and ZIF-8 composites.

    PubMed

    Li, Xueqin; Hao, Changlong; Tang, Bochong; Wang, Yue; Liu, Mei; Wang, Yuanwei; Zhu, Yihua; Lu, Chenguang; Tang, Zhiyong

    2017-02-09

    Due to their high specific surface area and good electric conductivity, nitrogen-doped porous carbons (NPCs) and carbon nanotubes (CNTs) have attracted much attention for electrochemical energy storage applications. In the present work, we firstly prepared MWCNT/ZIF-8 composites by decoration of zeolitic imidazolate frameworks (ZIF-8) onto the surface of multi-walled CNTs (MWCNTs), then obtained MWCNT/NPCs by the direct carbonization of MWCNT/ZIF-8. By controlling the reaction conditions, MWCNT/ZIF-8 with three different particle sizes were synthesized. The effect of NPCs size on capacitance performance has been evaluated in detail. The MWCNT/NPC with large-sized NPC (MWCNT/NPC-L) displayed the highest specific capacitance of 293.4 F g(-1) at the scan rate of 5 mV s(-1) and only lost 4.2% of capacitance after 10 000 cyclic voltammetry cycles, which was attributed to the hierarchically structured pores, N-doping and high electrical conductivity. The studies of symmetric two-electrode supercapacitor cells also confirmed MWCNT/NPC-L as efficient electrode materials that have good electrochemical performance, especially for high-rate applications.

  11. Biochar as a sustainable electrode material for electricity production in microbial fuel cells.

    PubMed

    Huggins, Tyler; Wang, Heming; Kearns, Joshua; Jenkins, Peter; Ren, Zhiyong Jason

    2014-04-01

    Wood-based biochars were used as microbial fuel cell electrodes to significantly reduce cost and carbon footprint. The biochar was made using forestry residue (BCc) and compressed milling residue (BCp). Side-by-side comparison show the specific area of BCp (469.9m(2)g(-1)) and BCc (428.6cm(2)g(-1)) is lower than granular activated carbon (GAC) (1247.8m(2)g(-1)) but higher than graphite granule (GG) (0.44m(2)g(-1)). Both biochars showed power outputs of 532±18mWm(-2) (BCp) and 457±20mWm(-2) (BCc), comparable with GAC (674±10mWm(-2)) and GG (566±5mWm(-2)). However, lower material expenses made their power output cost 17-35US$W(-1), 90% cheaper than GAC (402US$W(-1)) or GG (392US$W(-1)). Biochar from waste also reduced the energy and carbon footprint associated with electrode manufacturing and the disposal of which could have additional agronomic benefits.

  12. Quantifying Bulk Electrode Strain and Material Displacement within Lithium Batteries via High‐Speed Operando Tomography and Digital Volume Correlation

    PubMed Central

    Finegan, Donal P.; Tudisco, Erika; Scheel, Mario; Robinson, James B.; Taiwo, Oluwadamilola O.; Eastwood, David S.; Lee, Peter D.; Di Michiel, Marco; Bay, Brian; Hall, Stephen A.; Hinds, Gareth; Brett, Dan J. L.

    2015-01-01

    Tracking the dynamic morphology of active materials during operation of lithium batteries is essential for identifying causes of performance loss. Digital volume correlation (DVC) is applied to high‐speed operando synchrotron X‐ray computed tomography of a commercial Li/MnO2 primary battery during discharge. Real‐time electrode material displacement is captured in 3D allowing degradation mechanisms such as delamination of the electrode from the current collector and electrode crack formation to be identified. Continuum DVC of consecutive images during discharge is used to quantify local displacements and strains in 3D throughout discharge, facilitating tracking of the progression of swelling due to lithiation within the electrode material in a commercial, spiral‐wound battery during normal operation. Displacement of the rigid current collector and cell materials contribute to severe electrode detachment and crack formation during discharge, which is monitored by a separate DVC approach. Use of time‐lapse X‐ray computed tomography coupled with DVC is thus demonstrated as an effective diagnostic technique to identify causes of performance loss within commercial lithium batteries; this novel approach is expected to guide the development of more effective commercial cell designs. PMID:27610334

  13. A novel high capacity positive electrode material with tunnel-type structure for aqueous sodium-ion batteries

    DOE PAGES

    Wang, Yuesheng; Mu, Linqin; Liu, Jue; ...

    2015-08-06

    In this study, aqueous sodium-ion batteries have shown desired properties of high safety characteristics and low-cost for large-scale energy storage applications such as smart grid, because of the abundant sodium resources as well as the inherently safer aqueous electrolytes. Among various Na insertion electrode materials, tunnel-type Na0.44MnO2 has been widely investigated as a positive electrode for aqueous sodium-ion batteries. However, the low achievable capacity hinders its practical applications. Here we report a novel sodium rich tunnel-type positive material with a nominal composition of Na0.66[Mn0.66Ti0.34]O2. The tunnel-type structure of Na0.44MnO2 obtained for this compound was confirmed by XRD and atomic-scale STEM/EELS.more » When cycled as positive electrode in full cells using NaTi2(PO4)3/C as negative electrode in 1M Na2SO4 aqueous electrolyte, this material shows the highest capacity of 76 mAh g-1 among the Na insertion oxides with an average operating voltage of 1.2 V at a current rate of 2C. These results demonstrate that Na0.66[Mn0.66Ti0.34]O2 is a promising positive electrode material for rechargeable aqueous sodium-ion batteries.« less

  14. Novel synthesis of Ni-ferrite (NiFe{sub 2}O{sub 4}) electrode material for supercapacitor applications

    SciTech Connect

    Venkatachalam, V.; Jayavel, R.

    2015-06-24

    Novel nanocrystalline NiFe{sub 2}O{sub 4} has been synthesized through combustion route using citric acid as a fuel. Phase of the synthesized material was analyzed using powder X-ray diffraction. The XRD study revealed the formation of spinel phase cubic NiFe{sub 2}O{sub 4} with high crystallinity. The average crystallite size of NiFe{sub 2}O{sub 4} nanomaterial was calculated from scherrer equation. The electrochemical properties were realized by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. The electrode material shows a maximum specific capacitance of 454 F/g with pseudocapacitive behavior. High capacitance retention of electrode material over 1000 continuous charging-discharging cycles suggests its excellent electrochemical stability. The results revealed that the nickel ferrite electrode is a potential candidate for energy storage applications in supercapacitor.

  15. Novel synthesis of Ni-ferrite (NiFe2O4) electrode material for supercapacitor applications

    NASA Astrophysics Data System (ADS)

    Venkatachalam, V.; Jayavel, R.

    2015-06-01

    Novel nanocrystalline NiFe2O4 has been synthesized through combustion route using citric acid as a fuel. Phase of the synthesized material was analyzed using powder X-ray diffraction. The XRD study revealed the formation of spinel phase cubic NiFe2O4 with high crystallinity. The average crystallite size of NiFe2O4 nanomaterial was calculated from scherrer equation. The electrochemical properties were realized by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. The electrode material shows a maximum specific capacitance of 454 F/g with pseudocapacitive behavior. High capacitance retention of electrode material over 1000 continuous charging-discharging cycles suggests its excellent electrochemical stability. The results revealed that the nickel ferrite electrode is a potential candidate for energy storage applications in supercapacitor.

  16. Synthesis and characterization of NiCo2O4 nanoplates as efficient electrode materials for electrochemical supercapacitors

    NASA Astrophysics Data System (ADS)

    Kim, Taehyun; Ramadoss, Ananthakumar; Saravanakumar, Balasubramaniam; Veerasubramani, Ganesh Kumar; Kim, Sang Jae

    2016-05-01

    In the present work, NiCo2O4 nanoplates were prepared by a facile, low temperature, hydrothermal method, followed by thermal annealing and used supercapacitor applications. The physico-chemical characterization of as-prepared materials were investigated by means of X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR) and field emission scanning electron microscopy (FE-SEM). The electrochemical measurements demonstrate that the NiCo2O4 nanoplates electrode (NC-5) exhibits a high specific capacitance of 332 F g-1 at a scan rate of 5 mV s-1 and also retained about 86% of the initial specific capacitance value even after 2000 cycles at a current density of 2.5 A g-1. These results suggest that the fabricated electrode material has huge potential as a novel electrode material for electrochemical capacitors.

  17. Bridging Oriented Copper Nanowire-Graphene Composites for Solution-Processable, Annealing-Free, and Air-Stable Flexible Electrodes.

    PubMed

    Zhang, Wang; Yin, Zhenxing; Chun, Alvin; Yoo, Jeeyoung; Kim, Youn Sang; Piao, Yuanzhe

    2016-01-27

    One-dimensional flexible metallic nanowires (NWs) are of considerable interest for next-generation wearable devices. The unavoidable challenge for a wearable electrode is the assurance of high conductivity, flexibility, and durability with economically feasible materials and simple manufacturing processes. Here, we use a straightforward solvothermal method to prepare a flexible conductive material that contains reduced graphene oxide (RGO) nanosheets bridging oriented copper NWs. The GO-assistance route can successfully meet the criteria listed above and help the composite films maintain high conductivity and durable flexibility without any extra treatment, such as annealing or acid processes. The composite film exhibits a high electrical performance (0.808 Ω·sq(-1)) without considerable change over 30 days under ambient conditions. Moreover, the Cu NW-RGO composites can be deposited on polyester cloth as a lightweight wearable electrode with high durability and simple processability and are very promising for a wide variety of electronic devices.

  18. Conformal coating of thin polymer electrolyte layer on nanostructured electrode materials for three-dimensional battery applications.

    PubMed

    Gowda, Sanketh R; Reddy, Arava Leela Mohana; Shaijumon, Manikoth M; Zhan, Xiaobo; Ci, Lijie; Ajayan, Pulickel M

    2011-01-12

    Various three-dimensional (3D) battery architectures have been proposed to address effective power delivery in micro/nanoscale devices and for increasing the stored energy per electrode footprint area. One step toward obtaining 3D configurations in batteries is the formation of core-shell nanowires that combines electrode and electrolyte materials. One of the major challenges however in creating such architectures has been the coating of conformal thin nanolayers of polymer electrolytes around nanostructured electrodes. Here we show conformal coatings of 25-30 nm poly(methyl methacralate) electrolyte layers around individual Ni-Sn nanowires used as anodes for Li ion battery. This configuration shows high discharge capacity and excellent capacity retention even at high rates over extended cycling, allowing for scalable increase in areal capacity with electrode thickness. Our results demonstrate conformal nanoscale anode-electrolyte architectures for an efficient Li ion battery system.

  19. Fabrication and characterization of buckypaper-based nanostructured electrodes as a novel material for biofuel cell applications.

    PubMed

    Hussein, Laith; Urban, Gerald; Krüger, Michael

    2011-04-07

    The fabrication process of buckypapers (BPs) made from stable suspensions of as-received or functionalized multi-walled carbon nanotubes (MWCNTs) with high purity (97.5 wt%, Baytubes), their characterization and their utilization towards novel biofuel cell electrode applications are reported. The BPs can vary in thickness between 1 μm and 200 μm, are mechanically robust, flexible, stable in solvents, possess high meso-porosities as well as high apparent electrical conductivities of up to 2500 S m(-1). Potentiodynamic measurements of biocathodes based on bilirubin oxidase (BOD)-decorated BPs for the oxygen reduction reaction (ORR) in neutral media (phosphate buffer solution) containing glucose indicate that BP electrodes based on functionalized MWCNTs (fBPs) perform better than BP electrodes of as-received MWCNTs and have high potential as an effective electrode material in biofuel cells and biosensors.

  20. Nano-graphite functionalized mesocellular carbon foam with enhanced intra-penetrating electrical percolation networks for high performance electrochemical energy storage electrode materials.

    PubMed

    Jo, Changshin; An, Sunhyung; Kim, Younghoon; Shim, Jongmin; Yoon, Songhun; Lee, Jinwoo

    2012-04-28

    Mesocellular carbon foam (MSU-F-C) is functionalized with hollow nanographite by a simple solution-phase method to enhance the intrapenetrating electrical percolation network. The electrical conductivity of the resulting material, denoted as MSU-F-C-G, is increased by a factor of 20.5 compared with the pristine MSU-F-C. Hollow graphite nanoparticles are well-dispersed in mesocellular carbon foam, as confirmed by transmission electron microscopy (TEM), and the d spacing of the (002) planes is 0.343 nm, which is only slightly larger than that of pure graphite (0.335 nm), suggesting a random combination of graphitic and turbostratic stacking. After nanographitic functionalization, the BET surface area and total pore volume decreased from 928 m(2) g(-1) and 1.5 cm(3) g(-1) to 394 m(2) g(-1) and 0.7 cm(3) g(-1), respectively. Thermogravimetric analysis in air shows that the thermal stability of MSU-F-C-G is improved relative to that of MSU-F-C, and the one-step weight loss indicates that the nanographite is homogeneously functionalized on the MSU-F-C particles. When the resulting mesocellular carbon materials are used as electrode materials for an electric double layer capacitor (EDLC), the specific capacitances (C(sp)) of the MSU-F-C and MSU-F-C-G electrodes at 4 mV s(-1) are 109 F g(-1) and 93 F g(-1), respectively. The MSU-F-C-G electrode exhibited a very high area capacitance (C(area), 23.5 μF cm(-2)) compared with that of the MSU-F-C electrode (11.7 μF cm(-2)), which is attributed to the enhanced intraparticle conductivity by the nanographitic functionalization. MSU-F-C-G exhibited high capacity retention (52%) at a very high scan rate of 512 mV s(-1), while only a 23% capacity retention at 512 mV s(-1) was observed in the case of the MSU-F-C electrode. When applied as an anode in a lithium ion battery, a significant increase in the initial efficiency (44%), high reversible discharge capacity (580 mA h g(-1)) in the lower voltage region, and a higher rate

  1. Hollow graphitic nanocapsules as efficient electrode materials for sensitive hydrogen peroxide detection.

    PubMed

    Liu, Wei-Na; Ding, Ding; Song, Zhi-Ling; Bian, Xia; Nie, Xiang-Kun; Zhang, Xiao-Bing; Chen, Zhuo; Tan, Weihong

    2014-02-15

    Carbon nanomaterials are typically used in electrochemical biosensing applications for their unique properties. We report a hollow graphitic nanocapsule (HGN) utilized as an efficient electrode material for sensitive hydrogen peroxide detection. Methylene blue (MB) molecules could be efficiently adsorbed on the HGN surfaces, and this adsorption capability remained very stable under different pH regimes. HGNs were used as three-dimensional matrices for coimmobilization of MB electron mediators and horseradish peroxidase (HRP) to build an HGN-HRP-MB reagentless amperometric sensing platform to detect hydrogen peroxide. This simple HGN-HRP-MB complex demonstrated very sensitive and selective hydrogen peroxide detection capability, as well as high reproducibility and stability. The HGNs could also be utilized as matrices for immobilization of other enzymes, proteins or small molecules and for different biomedical applications.

  2. Preliminary result on the enhancement of Ufer electrodes using recycle additives materials

    NASA Astrophysics Data System (ADS)

    Zulkifli, Muhammad Haziq Aniq Bin; Ahmad, Hussein Bin

    2016-11-01

    Ground building pillars is to be used as ground rod. The pillars are design, fabricated, and formulated with new ground fillers. The additives will be used from recycle waste materials mainly from the palm oil plant process. Micro scale building pillars will be fabricated and install in the test ground at all of the location. Earth tester meter are used to measure and collect the data of the soil resistivity when the research is conducted. In collecting these data, 3-terminal methods are used to carry the measurements. This experiment will be conducted for 30 weeks and regular measurements at the test ground copper grids will be conducted to measure the ground electrode resistance. The study will mainly base on IEC 62503-3. The used of reinforcing rods and mixture of recycle additives could produce a better grounding system that are suitable and can be used in all kind of soil condition and large industries.

  3. The performance of La0.6Sr1.4MnO4 layered perovskite electrode material for intermediate temperature symmetrical solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Zhou, Jun; Chen, Gang; Wu, Kai; Cheng, Yonghong

    2014-12-01

    A layered perovskite electrode material, La0.6Sr1.4MnO4+δ (LSMO4), has been studied for intermediate temperature symmetrical solid oxide fuel cells (IT-SSOFCs) on La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) electrolyte. The chemical compatibility tests indicate that no reaction occurred between LSMO4 oxide and LSGM electrolyte at temperature up to 1000 °C both in air and 5% H2. The lower conductivity in 5% H2 and higher conduction activation energy than those in air would be caused by poorer overlap of both σ and π bonds. DFT + U calculations also show that oxygen vacancies which formed in reducing atmosphere may block the 3D hopping path for electrons or holes through Mn-O-Mn chains. For LSMO4 electrode, SEM results indicate that the electrode formed good contact with the electrolyte after being sintered at 900 °C for 2 h. At 800 °C, the polarization resistance of the LSMO4 cathode is about 0.87 Ω cm2 in air, while the polarization resistance of the LSMO4 anode is about 2.07 Ω cm2 in 5% H2. LSMO4 exhibits better electrochemical activity for oxygen reduction than that for hydrogen oxidation. A cell with LSGM electrolyte, LSMO4-LSGM mixture as anode and cathode simultaneously displays a maximum power density of 59 mW cm-2 at 800 °C.

  4. Synthesis, characterization, and electrochemical investigation of novel electrode materials for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Kerr, Tracy Alexandra

    2002-08-01

    As the demand for better energy storage devices increases, finding new materials capable of improvement on existing technology becomes essential. Within this body of work, several new electrode materials of different structure type have been synthesized, characterized, and evaluated for their lithium insertion/deinsertion behavior in lithium ion batteries. Nanocomposites of novel alloy, and convertible oxide anode materials have been studied. Nanoparticles of Ge and Sn that are able to form lithium rich alloys have been synthesized, and their low potential lithium insertion behavior studied. In order to inhibit agglomeration of the tiny particles, a novel synthesis route was designed to attach ionically conducting polymers to their surfaces. Characterization by a combination of techniques (XRD, TEM, SEM and FTIR spectroscopy) verified the existence of nanoparticles embedded in a polymer matrix, albeit with some impurities. Electrochemical data show that even when the lithium insertion capacity within these materials is high, the process is extremely irreversible as lithium ions become trapped within the matrix, and only a very small anodic capacity is realized. The first convertible polymer/oxide nanocomposite (poly(para-phenylene)/MoO 3) to be evaluated as an anode material was synthesized using a novel surfactant mediated method. XRD data indicated a 5.2 A increase in the MoO3 layer spacing to 12.1 A after polymer incorporation. Low potential electrochemical insertion properties show that the polymer/oxide nanocomposite behaves in a similar manner to the host MoO3 material. A variety of cathode materials were also synthesized and evaluated for their high potential lithium insertion properties. A comparative study on the effect that synthetic procedure may have on the electrochemical properties of the poly(aniline)/MoO3 cathode material have been studied. Poly(aniline)/MoO 3 nanocomposites have been synthesized from a solution insertion route and via hydrothermal

  5. Few-layer MoS2-anchored graphene aerogel paper for free-standing electrode materials

    NASA Astrophysics Data System (ADS)

    Lee, Wee Siang Vincent; Peng, Erwin; Loh, Tamie Ai Jia; Huang, Xiaolei; Xue, Jun Min

    2016-04-01

    To reduce the reliance on polymeric binders, conductive additives, and metallic current collectors during the electrode preparation process, as well as to assess the true performance of lithium ion battery (LIB) anodes, a free-standing electrode has to be meticulously designed. Graphene aerogel is a popular scaffolding material that has been widely used with embedded nanoparticles for application in LIB anodes. However, the current graphene aerogel/nanoparticle composite systems still involve decomposition into powder and the addition of additives during electrode preparation because of the thick aerogel structure. To further enhance the capacity of the system, MoS2 was anchored onto a graphene aerogel paper and the composite was used directly as an LIB anode. The resultant additive-free MoS2/graphene aerogel paper composite exhibited long cyclic performance with 101.1% retention after 700 cycles, which demonstrates the importance of free-standing electrodes in enhancing cyclic stability.To reduce the reliance on polymeric binders, conductive additives, and metallic current collectors during the electrode preparation process, as well as to assess the true performance of lithium ion battery (LIB) anodes, a free-standing electrode has to be meticulously designed. Graphene aerogel is a popular scaffolding material that has been widely used with embedded nanoparticles for application in LIB anodes. However, the current graphene aerogel/nanoparticle composite systems still involve decomposition into powder and the addition of additives during electrode preparation because of the thick aerogel structure. To further enhance the capacity of the system, MoS2 was anchored onto a graphene aerogel paper and the composite was used directly as an LIB anode. The resultant additive-free MoS2/graphene aerogel paper composite exhibited long cyclic performance with 101.1% retention after 700 cycles, which demonstrates the importance of free-standing electrodes in enhancing cyclic

  6. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors

    NASA Astrophysics Data System (ADS)

    Wang, Ronghua; Han, Meng; Zhao, Qiannan; Ren, Zonglin; Guo, Xiaolong; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-03-01

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10–20 nm are uniformly composited with GNS by a two-step hydrothermal-assistant chemical oxidation polymerization process; while PANi nanofibers with diameter of 50~100 nm are obtained by a one-step direct hydrothermal process. Benefitting from the ultrathin layer and porous structure, the sheet-like GNS/PANi composites can deliver specific capacitances of 532.3 to 304.9 F/g at scan rates of 2 to 50 mV/s. And also, this active material showed very good stability with capacitance retention as high as ~99.6% at scan rate of 50 mV/s, indicating a great potential for using in supercapacitors. Furthermore, the effects of hydrothermal temperatures on the electrochemical performances were systematically studied and discussed.

  7. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors.

    PubMed

    Wang, Ronghua; Han, Meng; Zhao, Qiannan; Ren, Zonglin; Guo, Xiaolong; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-03-14

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10-20 nm are uniformly composited with GNS by a two-step hydrothermal-assistant chemical oxidation polymerization process; while PANi nanofibers with diameter of 50~100 nm are obtained by a one-step direct hydrothermal process. Benefitting from the ultrathin layer and porous structure, the sheet-like GNS/PANi composites can deliver specific capacitances of 532.3 to 304.9 F/g at scan rates of 2 to 50 mV/s. And also, this active material showed very good stability with capacitance retention as high as ~99.6% at scan rate of 50 mV/s, indicating a great potential for using in supercapacitors. Furthermore, the effects of hydrothermal temperatures on the electrochemical performances were systematically studied and discussed.

  8. Nitrogen-doped reduced graphene oxide as electrode material for high rate supercapacitors

    NASA Astrophysics Data System (ADS)

    Śliwak, Agata; Grzyb, Bartosz; Díez, Noel; Gryglewicz, Grażyna

    2017-03-01

    Nitrogen-doped reduced graphene oxides (N-rGOs) have been synthesized at various temperatures by a facile hydrothermal route involving the doping of an aqueous graphene oxide dispersion with amitrole. The N-rGOs had a nitrogen content ranging from 10.9 to 13.4 at%, which is among the highest reported for this type of material. The predominant nitrogen species were pyridinic followed by amide/amine, pyrrolic, and quaternary nitrogen. Cyclic voltammetry and impedance spectroscopy measurements performed on the N-doped and nitrogen-free samples revealed that nitrogen fixation provided the material with pseudocapacitive behaviour and improved ion diffusion and charge propagation. A high specific capacitance of 244 F g-1 was obtained at a high scan rate of 100 mV s-1 for the N-rGO with the highest nitrogen content. An outstanding rate capability for the N-rGO, with increasing scan rates, of 98% was obtained, while only 70% was obtained for the non-doped rGO. 92% of the initial capacitance was maintained over 5000 charge/discharge cycles due to the high stability of the electrochemically active nitrogen moieties. Hydrothermal synthesis using amitrole as a nitrogen dopant represents a simple route for the synthesis of graphene with very high nitrogen content and exceptional behaviour for use as electrode material in high-power supercapacitors.

  9. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors

    PubMed Central

    Wang, Ronghua; Han, Meng; Zhao, Qiannan; Ren, Zonglin; Guo, Xiaolong; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-01-01

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10–20 nm are uniformly composited with GNS by a two-step hydrothermal-assistant chemical oxidation polymerization process; while PANi nanofibers with diameter of 50~100 nm are obtained by a one-step direct hydrothermal process. Benefitting from the ultrathin layer and porous structure, the sheet-like GNS/PANi composites can deliver specific capacitances of 532.3 to 304.9 F/g at scan rates of 2 to 50 mV/s. And also, this active material showed very good stability with capacitance retention as high as ~99.6% at scan rate of 50 mV/s, indicating a great potential for using in supercapacitors. Furthermore, the effects of hydrothermal temperatures on the electrochemical performances were systematically studied and discussed. PMID:28291246

  10. Impedance spectroscopic analysis of composite electrode from activated carbon/conductive materials/ruthenium oxide for supercapacitor applications

    SciTech Connect

    Taer, E.; Awitdrus,; Farma, R.; Deraman, M. Talib, I. A.; Ishak, M. M.; Omar, R.; Dolah, B. N. M.; Basri, N. H.; Othman, M. A. R.; Kanwal, S.

    2015-04-16

    Activated carbon powders (ACP) were produced from the KOH treated pre-carbonized rubber wood sawdust. Different conductive materials (graphite, carbon black and carbon nanotubes (CNTs)) were added with a binder (polivinylidene fluoride (PVDF)) into ACP to improve the supercapacitive performance of the activated carbon (AC) electrodes. Symmetric supercapacitor cells, fabricated using these AC electrodes and 1 molar H{sub 2}SO{sub 4} electrolyte, were analyzed using a standard electrochemical impedance spectroscopy technique. The addition of graphite, carbon black and CNTs was found effective in reducing the cell resistance from 165 to 68, 23 and 49 Ohm respectively, and increasing the specific capacitance of the AC electrodes from 3 to 7, 17, 32 F g{sup −1} respectively. Since the addition of CNTs can produce the highest specific capacitance, CNTs were chosen as a conductive material to produce AC composite electrodes that were added with 2.5 %, 5 % and 10 % (by weight) electro-active material namely ruthenium oxide; PVDF binder and CNTs contents were kept at 5 % by weight in each AC composite produced. The highest specific capacitance of the cells obtained in this study was 86 F g{sup −1}, i.e. for the cell with the resistance of 15 Ohm and composite electrode consists of 5 % ruthenium oxide.

  11. Evaluation of Niobium as Candidate Electrode Material for DC High Voltage Photoelectron Guns

    NASA Technical Reports Server (NTRS)

    BastaniNejad, M.; Mohamed, Abdullah; Elmustafa, A. A.; Adderley, P.; Clark, J.; Covert, S.; Hansknecht, J.; Hernandez-Garcia, C.; Poelker, M.; Mammei, R.; Surles-Law, K.; Williams, P.

    2012-01-01

    The field emission characteristics of niobium electrodes were compared to those of stainless steel electrodes using a DC high voltage field emission test apparatus. A total of eight electrodes were evaluated: two 304 stainless steel electrodes polished to mirror-like finish with diamond grit and six niobium electrodes (two single-crystal, two large-grain, and two fine-grain) that were chemically polished using a buffered-chemical acid solution. Upon the first application of high voltage, the best large-grain and single-crystal niobium electrodes performed better than the best stainless steel electrodes, exhibiting less field emission at comparable voltage and field strength. In all cases, field emission from electrodes (stainless steel and/or niobium) could be significantly reduced and sometimes completely eliminated, by introducing krypton gas into the vacuum chamber while the electrode was biased at high voltage. Of all the electrodes tested, a large-grain niobium electrode performed the best, exhibiting no measurable field emission (< 10 pA) at 225 kV with 20 mm cathode/anode gap, corresponding to a field strength of 18:7 MV/m.

  12. Comparison of electrode reduction activities of Geobacter sulfurreducens and an enriched consortium in an air-cathode microbial fuel cell.

    PubMed

    Ishii, Shun'ichi; Watanabe, Kazuya; Yabuki, Soichi; Logan, Bruce E; Sekiguchi, Yuji

    2008-12-01

    An electricity-generating bacterium, Geobacter sulfurreducens PCA, was inoculated into a single-chamber, air-cathode microbial fuel cell (MFC) in order to determine the maximum electron transfer rate from bacteria to the anode. To create anodic reaction-limiting conditions, where electron transfer from bacteria to the anode is the rate-limiting step, anodes with electrogenic biofilms were reduced in size and tests were conducted using anodes of six different sizes. The smallest anode (7 cm(2), or 1.5 times larger than the cathode) achieved an anodic reaction-limiting condition as a result of a limited mass of bacteria on the electrode. Under these conditions, the limiting current density reached a maximum of 1,530 mA/m(2), and power density reached a maximum of 461 mW/m(2). Per-biomass efficiency of the electron transfer rate was constant at 32 fmol cell(-1) day(-1) (178 micromol g of protein(-1) min(-1)), a rate comparable to that with solid iron as the electron acceptor but lower than rates achieved with fumarate or soluble iron. In comparison, an enriched electricity-generating consortium reached 374 micromol g of protein(-1) min(-1) under the same conditions, suggesting that the consortium had a much greater capacity for electrode reduction. These results demonstrate that per-biomass electrode reduction rates (calculated by current density and biomass density on the anode) can be used to help make better comparisons of electrogenic activity in MFCs.

  13. Preliminary study on zinc-air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction

    NASA Astrophysics Data System (ADS)

    Wen, Yue-Hua; Cheng, Jie; Ning, Shang-Qi; Yang, Yu-Sheng

    A zinc-air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction is reported in this paper. It possesses functions of both zincate reduction and electrochemical preparation, showing the potential for increasing the electronic energy utilization. Charge/discharge tests and scanning electron microscopy (SEM) micrographs reveal that when a nickel sheet plated with the high-H 2-overpotential metal, cadmium, was used as the negative substrate electrode, the dendritic formation and hydrogen evolution are suppressed effectively, and granular zinc deposits become larger but relatively dense with the increase of charge time. The performance of batteries is favorable even if the charge time is as long as 5 h at the current density of 20 mA cm -2. Better discharge performance is achieved using a 'cavity-opening' configuration for the discharge cell rather than a 'gas-introducing' configuration. The highest energy efficiency is up to 59.2%. That is, the energy consumed by organic electro-synthesis can be recovered by 59.2%. Cyclic voltammograms show that the sintered nickel electrode exhibits a good electro-catalysis activity for the propanol oxidation. The increase of propanol concentration conduces to an enhancement in the organic electro-synthesis efficiency. The organic electro-synthesis current efficiency of 82% can be obtained.

  14. Laboratory-scale testing of non-consumable anode materials: Inert Electrodes Program

    SciTech Connect

    Marschman, S.C.

    1989-03-01

    Development of inert anode materials for use in the electrolytic production of aluminum is one of the major goals of the Inert Electrodes Program sponsored by the US Department of Energy, Office of Industrial Programs, at Pacific Northwest Laboratory. The objectives of the Materials Development and Testing Task include the selection, fabrication, and evaluation of candidate non-consumable anode materials. Research performed in FY 1987 focused primarily on the development and evaluation of cermets that are based on the two-phase oxide system NiO/endash/NiFe/sub 2/O/sub 4/ and contain a third, electrically conductive metal phase composed primarily of copper and nickel. The efforts of this task were focused on three areas: materials fabrication, small-scale materials testing, and laboratory-scale testing. This report summarizes the development and testing results of the laboratory-scale testing effort during FY 1987. The laboratory-scale electrolysis testing effort was instrumental in partially determining electrolysis cell operating parameters. Although not optimized, NiO/endash/NiFe/sub 2/O/sub 4//endash/Cu-based cermets were successfully operated for 20 h in cryolite-based electrolytes ranging in bath ratios from 1.1 to 1.35, in electrolytes that contained 1.5 wt % LiF, and at conditions slightly less than Al/sub 2/O/sub 3/ saturation. The operating conditions that lead to anode degradation have been partly identified, and rudimentary control methods have been developed to ensure proper operation of small electrolysis cells using nonconsumable anodes. 11 figs., 1 tab.

  15. Switching and memory characteristics of thin films of an ambipolar organic compound: effects of device processing and electrode materials

    NASA Astrophysics Data System (ADS)

    Lee, Myung-Won; Pearson, Christopher; Moon, Tae Jung; Fisher, Alison L.; Petty, Michael C.

    2014-12-01

    We report on the effects of device processing conditions, and of changing the electrode materials, on the switching and negative differential resistance (NDR) behaviour of metal/organic thin film/metal structures. The organic material was an ambipolar molecule containing both electron transporting (oxadiazole) and hole transporting (carbazole) chemical groups. Switching and NDR effects are observed for device architectures with both electrodes consisting of aluminium; optimized switching behaviour is achieved for structures incorporating gold nanoparticles. If one of the Al electrodes is replaced by a higher work function metal or coated with an electron-blocking layer, switching and NDR are no longer observed. The results are consistent with a model based on the creation and destruction of Al filaments within the thin organic layer.

  16. Development of Nano-structured Electrode Materials for High Performance Energy Storage System

    NASA Astrophysics Data System (ADS)

    Huang, Zhendong

    Systematic studies have been done to develop a low cost, environmental-friendly facile fabrication process for the preparation of high performance nanostructured electrode materials and to fully understand the influence factors on the electrochemical performance in the application of lithium ion batteries (LIBs) or supercapacitors. For LIBs, LiNi1/3Co1/3Mn1/3O2 (NCM) with a 1D porous structure has been developed as cathode material. The tube-like 1D structure consists of inter-linked, multi-facet nanoparticles of approximately 100-500nm in diameter. The microscopically porous structure originates from the honeycomb-shaped precursor foaming gel, which serves as self-template during the stepwise calcination process. The 1D NCM presents specific capacities of 153, 140, 130 and 118mAh·g-1 at current densities of 0.1C, 0.5C, 1C and 2C, respectively. Subsequently, a novel stepwise crystallization process consisting of a higher crystallization temperature and longer period for grain growth is employed to prepare single crystal NCM nanoparticles. The modified sol-gel process followed by optimized crystallization process results in significant improvements in chemical and physical characteristics of the NCM particles. They include a fully-developed single crystal NCM with uniform composition and a porous NCM architecture with a reduced degree of fusion and a large specific surface area. The NCM cathode material with these structural modifications in turn presents significantly enhanced specific capacities of 173.9, 166.9, 158.3 and 142.3mAh·g -1 at 0.1C, 0.5C, 1C and 2C, respectively. Carbon nanotube (CNT) is used to improve the relative low power capability and poor cyclic stability of NCM caused by its poor electrical conductivity. The NCM/CNT nanocomposites cathodes are prepared through simply mixing of the two component materials followed by a thermal treatment. The CNTs were functionalized to obtain uniformly-dispersed MWCNTs in the NCM matrix. The electrochemical

  17. Cerium oxide nanoparticles/multi-wall carbon nanotubes composites: Facile synthesis and electrochemical performances as supercapacitor electrode materials

    NASA Astrophysics Data System (ADS)

    Deng, Dongyang; Chen, Nan; Li, Yuxiu; Xing, Xinxin; Liu, Xu; Xiao, Xuechun; Wang, Yude

    2017-02-01

    Cerium oxide nanoparticles/multi-wall carbon nanotubes (MWCNTs) composites are synthesized by a facile hydrothermal method without any surfactant or template. The morphology and microstructure of samples are examined by scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray diffraction (XRD), Raman spectrum and X-ray photoelectron spectroscopy (XPS). Electrochemical properties of the MWCNTs, the pure CeO2, and the CeO2/MWCNTs nanocomposites electrodes are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GDC) and electrochemical impedance spectroscopy (EIS) measurements. The CeO2/MWCNTs nanocomposite (at the mole ratio of 1:1) electrode exhibits much larger specific capacitance compared with both the MWCNTs electrode and the pure CeO2 electrode and significantly improves cycling stability compared to the pure CeO2 electrode. The CeO2/MWCNTs nanocomposite (at the mole ratio of 1:1) achieves a specific capacitance of 455.6 F g-1 at the current density of 1 A g-1. Therefore, the as prepared CeO2/MWCNTs nanocomposite is a promising electrode material for high-performance supercapacitors.

  18. Influence of air flow parameters on nanosecond repetitively pulsed discharges in a pin-annular electrode configuration

    NASA Astrophysics Data System (ADS)

    Heitz, Sylvain A.; Moeck, Jonas P.; Schuller, Thierry; Veynante, Denis; Lacoste, Deanna A.

    2016-04-01

    The effect of various air flow parameters on the plasma regimes of nanosecond repetitively pulsed (NRP) discharges is investigated at atmospheric pressure. The two electrodes are in a pin-annular configuration, transverse to the mean flow. The voltage pulses have amplitudes up to 15 kV, a duration of 10 ns and a repetition frequency ranging from 15 to 30 kHz. The NRP corona to NRP spark (C-S) regime transition and the NRP spark to NRP corona (S-C) regime transition are investigated for different steady and harmonically oscillating flows. First, the strong effect of a transverse flow on the C-S and S-C transitions, as reported in previous studies, is verified. Second, it is shown that the azimuthal flow imparted by a swirler does not affect the regime transition voltages. Finally, the influence of low frequency harmonic oscillations of the air flow, generated by a loudspeaker, is studied. A strong effect of frequency and amplitude of the incoming flow modulation on the NRP plasma regime is observed. Results are interpreted based on the cumulative effect of the NRP discharges and an analysis of the residence times of fluid particles in the inter-electrode region.

  19. High performance air electrode for solid oxide regenerative fuel cells fabricated by infiltration of nano-catalysts

    NASA Astrophysics Data System (ADS)

    Lee, Sung-il; Kim, Jeonghee; Son, Ji-Won; Lee, Jong-Ho; Kim, Byung-Kook; Je, Hae-June; Lee, Hae-Weon; Song, Huesup; Yoon, Kyung Joong

    2014-03-01

    A high performance air electrode fabricated by infiltration of highly active nano-catalysts into a porous scaffold is demonstrated for high-temperature solid oxide regenerative fuel cells (SORFCs). The nitrate precursor solution for Sm0.5Sr0.5CoO3 (SSC) catalyst is impregnated into a porous La0.6Sr0.4Co0.2Fe0.8O3 (LSCF)-gadolinia-doped ceria (GDC) composite backbone, and extremely fine SSC nano-particles are uniformly synthesized by in-situ crystallization at the initial stage of SORFC operation via homogeneous nucleation induced by urea decomposition. The SSC nano-catalysts are in the size range of 40-80 nm and stable against coarsening upon the SORFC operation at 750 °C. The electrochemical performance is significantly improved by incorporation of SSC nano-catalysts in both power generation and hydrogen production modes. Systematic analysis on the impedance spectra reveals that the surface modification of the air electrode with nano-catalysts remarkably accelerates the chemical surface exchange reactions for both O2 reduction and O2- oxidation, which are the major limiting processes for SORFC performance.

  20. The Role of Air-Electrode Structure on the Incorporation of Immiscible PFCs in Nonaqueous Li-O2 Battery.

    PubMed

    Balaish, Moran; Ein-Eli, Yair

    2017-03-22

    Perfluorocarbons (PFCs) are considered advantageous additives to nonaqueous Li-O2 battery due to their superior oxygen solubility and diffusivity compared to common battery electrolytes. Up to now, the main focus was concentrated on PFCs-electrolyte investigation; however, no special attention was granted to the role of carbon structure in the PFCs-Li-O2 system. In our current research, immiscible PFCs, rather than miscible fluorinated ethers, were added to activated carbon class air electrode due to their higher susceptibility toward O2(•-) attack and to their ability to shift the reaction from two-phase to an artificial three-phase reaction zone. The results showed superior battery performance upon PFCs addition at lower current density (0.05 mA cm(-2)) but unexpectedly failed to do so at higher current density (0.1 and 0.2 mA cm(-2)), where oxygen transport limitation is best illustrated. The last was a direct result of liquid-liquid displacement phenomenon occurring when the two immiscible liquids were introduced into the porous carbon medium. The investigation and role of carbon structure on the mechanism upon PFCs addition to Li-O2 system are suggested based on electrochemical characterization, wettability behavior studies, and the physical adsorption technique. Finally, we suggest an optimum air-electrode structure enabling the incorporation of immiscible PFCs in a nonaqueous Li-O2 battery.

  1. Amorphous carbon nitride as an alternative electrode material in electroanalysis: simultaneous determination of dopamine and ascorbic acid.

    PubMed

    Medeiros, Roberta A; Matos, Roberto; Benchikh, Abdelkader; Saidani, Boualem; Debiemme-Chouvy, Catherine; Deslouis, Claude; Rocha-Filho, Romeu C; Fatibello-Filho, Orlando

    2013-10-03

    Boron-doped diamond (BDD) films are excellent electrode materials, whose electrochemical activity for some analytes can be tuned by controlling their surface termination, most commonly either to predominantly hydrogen or oxygen. This tuning can be accomplished by e.g. suitable cathodic or anodic electrochemical pretreatments. Recently, it has been shown that amorphous carbon nitride (a-CNx) films may present electrochemical characteristics similar to those of BDD, including the influence of surface termination on their electrochemical activity toward some analytes. In this work, we report for the first time a complete electroanalytical method using an a-CNx electrode. Thus, an a-CNx film deposited on a stainless steel foil by DC magnetron sputtering is proposed as an alternative electrode for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) in synthetic biological samples by square-wave voltammetry. The obtained results are compared with those attained using a BDD electrode. For both electrodes, a same anodic pretreatment in 0.1 mol L(-1) KOH was necessary to attain an adequate and equivalent separation of the DA and AA oxidation potential peaks of about 330 mV. The detection limits obtained for the simultaneous determination of these analytes using the a-CNx electrode were 0.0656 μmol L(-1) for DA and 1.05 μmol L(-1) for AA, whereas with the BDD electrode these values were 0.283 μmol L(-1) and 0.968 μmol L(-1), respectively. Furthermore, the results obtained in the analysis of the analytes in synthetic biological samples were satisfactory, attesting the potential application of the a-CNx electrode in electroanalysis.

  2. Synthesis of NiMnO3/C nano-composite electrode materials for electrochemical capacitors

    NASA Astrophysics Data System (ADS)

    Kakvand, Pejman; Safi Rahmanifar, Mohammad; El-Kady, Maher F.; Pendashteh, Afshin; Kiani, Mohammad Ali; Hashami, Masumeh; Najafi, Mohsen; Abbasi, Ali; Mousavi, Mir F.; Kaner, Richard B.

    2016-08-01

    Demand for high-performance energy storage materials has motivated research activities to develop nano-engineered composites that benefit from both high-rate and high-capacitance materials. Herein, NiMnO3 (NMO) nanoparticles have been synthesized through a facile co-precipitation method. As-prepared NMO samples are then employed for the synthesis of nano-composites with graphite (Gr) and reduced graphene oxide (RGO). Various samples, including pure NMO, NMO-graphite blend, as well as NMO/Gr and NMO/RGO nano-composites have been electrochemically investigated as active materials in supercapacitors. The NMO/RGO sample exhibited a high specific capacitance of 285 F g-1 at a current density of 1 A g-1, much higher than the other samples (237 F g-1 for NMO/Gr, 170 F g-1 for NMO-Gr and 70 F g-1 for NMO). Moreover, the NMO/RGO nano-composite has shown excellent cycle stability with a 93.5% capacitance retention over 1000 cycles at 2 A g-1 and still delivered around 87% of its initial capacitance after cycling for 4000 cycles. An NMO/RGO composite was assessed in practical applications by assembling NMO/RGO//NMO/RGO symmetric devices, exhibiting high specific energy (27.3 Wh kg-1), high specific power (7.5 kW kg-1), and good cycle stability over a broad working voltage of 1.5 V. All the obtained results demonstrate the promise of NMO/RGO nano-composite as a high-performance electrode material for supercapacitors.

  3. Synthesis of NiMnO3/C nano-composite electrode materials for electrochemical capacitors.

    PubMed

    Kakvand, Pejman; Rahmanifar, Mohammad Safi; El-Kady, Maher F; Pendashteh, Afshin; Kiani, Mohammad Ali; Hashami, Masumeh; Najafi, Mohsen; Abbasi, Ali; Mousavi, Mir F; Kaner, Richard B

    2016-08-05

    Demand for high-performance energy storage materials has motivated research activities to develop nano-engineered composites that benefit from both high-rate and high-capacitance materials. Herein, NiMnO3 (NMO) nanoparticles have been synthesized through a facile co-precipitation method. As-prepared NMO samples are then employed for the synthesis of nano-composites with graphite (Gr) and reduced graphene oxide (RGO). Various samples, including pure NMO, NMO-graphite blend, as well as NMO/Gr and NMO/RGO nano-composites have been electrochemically investigated as active materials in supercapacitors. The NMO/RGO sample exhibited a high specific capacitance of 285 F g(-1) at a current density of 1 A g(-1), much higher than the other samples (237 F g(-1) for NMO/Gr, 170 F g(-1) for NMO-Gr and 70 F g(-1) for NMO). Moreover, the NMO/RGO nano-composite has shown excellent cycle stability with a 93.5% capacitance retention over 1000 cycles at 2 A g(-1) and still delivered around 87% of its initial capacitance after cycling for 4000 cycles. An NMO/RGO composite was assessed in practical applications by assembling NMO/RGO//NMO/RGO symmetric devices, exhibiting high specific energy (27.3 Wh kg(-1)), high specific power (7.5 kW kg(-1)), and good cycle stability over a broad working voltage of 1.5 V. All the obtained results demonstrate the promise of NMO/RGO nano-composite as a high-performance electrode material for supercapacitors.

  4. The Production and Characterization of Ceramic Carbon Electrode Materials for CuCl-HCl Electrolysis

    NASA Astrophysics Data System (ADS)

    Edge, Patrick

    Current H2 gas supplies are primarily produced through steam methane reforming and other fossil fuel based processes. This lack of viable large scale and environmentally friendly H2 gas production has hindered the wide spread adoption of H2 fuel cells. A potential solution to this problem is the Cu-Cl hybrid thermochemical cycle. The cycle captures waste heat to drive two thermochemical steps creating CuCl as well as O2 gas and HCl from CuCl2 and water. The CuCl is oxidized in HCl to produce H2 gas and regenerate CuCl2, this process occurs at potentials well below those required for water electrolysis. The electrolysis process occurs in a traditional PEM fuel-cell. In the aqueous anolyte media Cu(I) will form anionic complexes such as CuCl 2 - or CuCl32-. The slow transport of these species to the anode surface limits the overall electrolysis process. To improve this transport process we have produced ceramic carbon electrode (CCE) materials through a sol-gel method incorporating a selection of amine containing silanes with increasing numbers of primary and secondary amines. When protonated these amines allow for improved transport of anionic copper complexes. The electrochemical and physical characterization of these CCE materials in a half and full-cell electrolysis environment will be presented. Electrochemical analysis was performed using cell polarization, cyclic voltammetry, and electrochemical impedance spectroscopy.

  5. Ionic Liquid Directed Mesoporous Carbon Nanoflakes as an Effiencient Electrode material

    PubMed Central

    Kong, Lirong; Chen, Wei

    2015-01-01

    Supercapacitors are considered to be the most promising approach to meet the pressing requirements for energy storage devices. The electrode materials for supercapacitors have close relationship with their electrochemical properties and thus become the key point to improve their energy storage efficiency. Herein, by using poly (vinylidene fluoride-co-hexafluoropropylene) and ionic liquid as the dual templates, polyacrylonitrile as the carbon precursor, a flake-like carbon material was prepared by a direct carbonization method. In this method, poly (vinylidene fluoride-co-hexafluoropropylene) worked as the separator for the formation of isolated carbon flakes while aggregated ionic liquid worked as the pore template. The obtained carbon flakes exhibited a specific capacitance of 170 F/g at 0.1 A/g, a high energy density of 12.2 Wh/kg and a high power density of 5 kW/kg at the current of 10 A/g. It also maintained a high capacitance retention capability with almost no declination after 500 charge-discharge cycles. The ionic liquid directed method developed here also provided a new idea for the preparation of hierarchically porous carbon nanomaterials. PMID:26656464

  6. Recent Advancements in Flexible and Stretchable Electrodes for Electromechanical Sensors: Strategies, Materials, and Features.

    PubMed

    Zhao, Songfang; Li, Jinhui; Cao, Duxia; Zhang, Guoping; Li, Jia; Li, Kui; Yang, Yang; Wang, Wei; Jin, Yufeng; Sun, Rong; Wong, Ching-Ping

    2017-03-30

    Stretchable and flexible sensors attached onto the surface of the human body can perceive external stimuli, thus attracting extensive attention due to their lightweight, low modulus, low cost, high flexibility, and stretchability. Recently, a myriad of efforts have been devoted to improving the performance and functionality of wearable sensors. Herein, this review focuses on recent remarkable advancements in the development of flexible and stretchable sensors. Multifunction of these wearable sensors is realized by incorporating some desired features (e.g., self-healing, self-powering, linearity, and printing). Next, focusing on the characteristics of carbon nanomaterials, nanostructured metal, conductive polymer, or their hybrid composites, two major strategies (e.g., materials that stretch and structures that stretch) and diverse design approaches have been developed to achieve highly flexible and stretchable electrodes. Strain sensing performances of recently reported sensors indicate that the appropriate choice of geometric engineering as well as intrinsically stretchable materials is essential for high-performance strain sensing. Finally, some important directions and challenges of a fully sensor-integrated wearable platform are proposed to realize their potential applications for human motion monitoring and human-machine interfaces.

  7. α MnMoO₄/graphene hybrid composite: high energy density supercapacitor electrode material.

    PubMed

    Ghosh, Debasis; Giri, Soumen; Moniruzzaman, Md; Basu, Tanya; Mandal, Manas; Das, Chapal Kumar

    2014-07-28

    A unique and cost effective hydrothermal procedure has been carried out for the synthesis of hexahedron shaped α MnMoO4 and its hybrid composite with graphene using three different weight percentages of graphene. Characterization techniques, such as XRD, Raman and FTIR analysis, established the phase and formation of the composite. The electrochemical characterization of the pseudocapacitive MnMoO4 and the MnMoO4/graphene composites in 1 M Na2SO4 displayed highest specific capacitances of 234 F g(-1) and 364 F g(-1), respectively at a current density of 2 A g(-1). Unlike many other pseudocapacitive electrode materials our prepared materials responded in a wide range of working potentials of (-)1 V to (+)1 V, which indeed resulted in a high energy density without substantial loss of power density. The highest energy densities of 130 Wh kg(-1) and 202.2 Wh kg(-1) were achieved, respectively for the MnMoO4 and the MnMoO4/graphene composite at a constant power delivery rate of 2000 W kg(-1). The synergistic effect of the graphene with the pseudocapacitive MnMoO4 caused an increased cycle stability of 88% specific capacitance retention after 1000 consecutive charge discharge cycles at 8 A g(-1) constant current density, which was higher than the virgin MnMoO4 with 84% specific capacitance retention.

  8. CuSbS2 as a negative electrode material for sodium ion batteries

    NASA Astrophysics Data System (ADS)

    Marino, C.; Block, T.; Pöttgen, R.; Villevieille, C.

    2017-02-01

    CuSbS2 was tested as a negative electrode material for sodium-ion batteries. The material synthesized by ball milling offers a specific charge of 730 mAh g-1, close to the theoretical value (751 mAh g-1), over a few cycles. The reaction mechanism was investigated by means of operando X-ray diffraction, 121Sb Mössbauer spectroscopy, and Cu K-edge X-ray absorption spectroscopy. These studies reveal a sodiation mechanism that involves an original conversion reaction in two steps, through the formation of a ternary phase, CuSb(1-x)S(2-y), as well as a NaxS alloy and Sb, followed by an alloying reaction involving the previously formed Sb. The desodiation process ends with the reformation of the ternary phase, CuSb(1-x‧)S(2-y‧), deficient in Sb and S; this phase is responsible for the good reversibility observed upon cycling.

  9. Hexagonal CeO2 nanostructures: an efficient electrode material for supercapacitors.

    PubMed

    Maheswari, Nallappan; Muralidharan, Gopalan

    2016-09-28

    Cerium oxide (CeO2) has emerged as a new and promising pseudocapacitive material due to its prominent valance states and extensive applications in various fields. In the present study, hexagonal CeO2 nanostructures have been prepared via the hydrothermal method employing cationic surfactant cetyl trimethyl ammonium bromide (CTAB). CTAB ensures a slow rate of hydrolysis to form small sized CeO2 nanostructures. The role of calcination temperature on the morphological, structural, electrochemical properties and cyclic stability has been assessed for supercapacitor applications. The mesoscopic hexagonal architecture endows the CeO2 with not only a higher specific capacity, but also with an excellent rate capability and cyclability. When the charge/discharge current density is increased from 2 to 10 A g(-1) the reversible charge capacity decreased from 927 F g(-1) to 475 F g(-1) while 100% capacity retention at a high current density of 20 A g(-1) even after 1500 cycles could be achieved. Furthermore, the asymmetric supercapacitor based on CeO2 exhibited a significantly higher energy density of 45.6 W h kg(-1) at a power density of 187.5 W kg(-1) with good cyclic stability. The electrochemical richness of the CeO2 nanostructure makes it a suitable electrode material for supercapacitor applications.

  10. Kinetic modelling of molten carbonate fuel cells: Effects of cathode water and electrode materials

    NASA Astrophysics Data System (ADS)

    Arato, E.; Audasso, E.; Barelli, L.; Bosio, B.; Discepoli, G.

    2016-10-01

    Through previous campaigns the authors developed a semi-empirical kinetic model to describe MCFC performance for industrial and laboratory simulation. Although effective in a wide range of operating conditions, the model was validated for specific electrode materials and dry feeding cathode compositions. The new aim is to prove that with appropriate improvements it is possible to apply the model to MCFC provided by different suppliers and to new sets of reactant gases. Specifically, this paper describes the procedures to modify the model to switch among different materials and identify a new parameter taking into account the effects of cathode water vapour. The new equation is integrated as the kinetic core within the SIMFC (SIMulation of Fuel Cells) code, an MCFC 3D model set up by the PERT group of the University of Genova, for reliability test. Validation is performed using data collected through tests carried out at the University of Perugia using single cells. The results are discussed giving examples of the simulated performance with varying operating conditions. The final formulation average percentage error obtained for all the simulated cases with respect to experimental results is maintained around 1%, despite the difference between the basic and the new conditions and facilities.

  11. Sodium titanate nanotubes as negative electrode materials for sodium-ion capacitors.

    PubMed

    Yin, Jiao; Qi, Li; Wang, Hongyu

    2012-05-01

    The lithium-based energy storage technology is currently being considered for electric automotive industry and even electric grid storage. However, the hungry demand for vast energy sources in the modern society will conflict with the shortage of lithium resources on the earth. The first alternative choice may be sodium-related materials. Herein, we propose an electric energy storage system (sodium-ion capacitor) based on porous carbon and sodium titanate nanotubes (Na-TNT, Na(+)-insertion compounds) as positive and negative electrode materials, respectively, in conjunction with Na(+)-containing non-aqueous electrolytes. As a low-voltage (0.1-2 V) sodium insertion nanomaterial, Na-TNT was synthesized via a simple hydrothermal reaction. Compared with bulk sodium titanate, the predominance of Na-TNT is the excellent rate performance, which exactly caters to the need for electrochemical capacitors. The sodium-ion capacitors exhibited desirable energy density and power density (34 Wh kg(-1), 889 W kg(-1)). Furthermore, the sodium-ion capacitors had long cycling life (1000 cycles) and high coulombic efficiency (≈ 98 % after the second cycle). More importantly, the conception of sodium-ion capacitor has been put forward.

  12. A large-area diffuse air discharge plasma excited by nanosecond pulse under a double hexagon needle-array electrode.

    PubMed

    Liu, Zhi-Jie; Wang, Wen-Chun; Yang, De-Zheng; Wang, Sen; Zhang, Shuai; Tang, Kai; Jiang, Peng-Chao

    2014-01-01

    A large-area diffuse air discharge plasma excited by bipolar nanosecond pulse is generated under a double hexagon needle-array electrode at atmospheric pressure. The images of the diffuse discharge, electric characteristics, and the optical emission spectra emitted from the diffuse air discharge plasma are obtained. Based on the waveforms of pulse voltage and current, the power consumption, and the power density of the diffuse air discharge plasma are investigated under different pulse peak voltages. The electron density and the electron temperature of the diffuse plasma are estimated to be approximately 1.42×10(11) cm(-3) and 4.4 eV, respectively. The optical emission spectra are arranged to determine the rotational and vibrational temperatures by comparing experimental with simulated spectra. Meanwhile, the rotational and vibrational temperatures of the diffuse discharge plasma are also discussed under different pulse peak voltages and pulse repetition rates, respectively. In addition, the diffuse air discharge plasma can form an area of about 70×50 mm(2) on the surface of dielectric layer and can be scaled up to the required size.

  13. Fast fabrication of copper nanowire transparent electrodes by a high intensity pulsed light sintering technique in air.

    PubMed

    Ding, Su; Jiu, Jinting; Tian, Yanhong; Sugahara, Tohru; Nagao, Shijo; Suganuma, Katsuaki

    2015-12-14

    Copper nanowire transparent electrodes have received increasing interest due to the low price and nearly equal electrical conductivity compared with other TEs based on silver nanowires and indium tin oxide (ITO). However, a post-treatment at high temperature in an inert atmosphere or a vacuum environment was necessary to improve the conductivity of Cu NW TEs due to the easy oxidation of copper in air atmosphere, which greatly cancelled out the low price advantage of Cu NWs. Here, a high intensity pulsed light technique was introduced to sinter and simultaneously deoxygenate these Cu NWs into a highly conductive network at room temperature in air. The strong light absorption capacity of Cu NWs enabled the welding of the nanowires at contact spots, as well as the removal of the thin layer of residual organic compounds, oxides and hydroxide of copper even in air. The Cu NW TE with a sheet resistance of 22.9 Ohm sq(-1) and a transparency of 81.8% at 550 nm has been successfully fabricated within only 6 milliseconds exposure treatment, which is superior to other films treated at high temperature in a hydrogen atmosphere. The HIPL process was simple, convenient and fast to fabricate easily oxidized Cu NW TEs in large scale in an air atmosphere, which will largely extend the application of cheap Cu NW TEs.

  14. Silver nanoparticle-decorated carbon nanotubes as bifunctional gas-diffusion electrodes for zinc-air batteries

    NASA Astrophysics Data System (ADS)

    Wang, T.; Kaempgen, M.; Nopphawan, P.; Wee, G.; Mhaisalkar, S.; Srinivasan, M.

    Thin, lightweight, and flexible gas-diffusion electrodes (GDEs) based on freestanding entangled networks of single-walled carbon nanotubes (SWNTs) decorated with Ag nanoparticles (AgNPs) are tested as the air-breathing cathode in a zinc-air battery. The SWNT networks provide a highly porous surface for active oxygen absorption and diffusion. The high conductivity of SWNTs coupled with the catalytic activity of AgNPs for oxygen reduction leads to an improvement in the performance of the zinc-air cell. By modulating the pH value and the reaction time, different sizes of AgNPs are decorated uniformly on the SWNTs, as revealed by transmission electron microscopy and powder X-ray diffraction. AgNPs with sizes of 3-5 nm double the capacity and specific energy of a zinc-air battery as compared with bare SWNTs. The simplified, lightweight architecture shows significant advantages over conventional carbon-based GDEs in terms of weight, thickness and conductivity, and hence may be useful for mobile and portable applications.

  15. Polyaniline silver nanoparticle coffee waste extracted porous graphene oxide nanocomposite structures as novel electrode material for rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Sundriyal, Poonam; Bhattacharya, Shantanu

    2017-03-01

    The exploration of new and advanced electrode materials are required in electronic and electrical devices for power storage applications. Also, there has been a continuous endeavour to formulate strategies for extraction of high performance electrode materials from naturally obtained waste products. In this work, we have developed an in situ hybrid nanocomposite from coffee waste extracted porous graphene oxide (CEPG), polyaniline (PANI) and silver nanoparticles (Ag) and have found this novel composite to serve as an efficient electrode material for batteries. The successful interaction among the three phases of the nano-composite i.e. CEPG–PANI–Ag have been thoroughly understood through RAMAN, Fourier transform infrared and x-ray diffraction spectroscopy, morphological studies through field emission scanning electron microscope and transmission electron microscope. Thermo-gravimetric analysis of the nano-composite demonstrates higher thermal stability up-to a temperature of 495 °C. Further BET studies through nitrogen adsorption–desorption isotherms confirm the presence of micro/meso and macro-pores in the nanocomposite sample. The cyclic-voltammetry (CV) analysis performed on CEPG–PANI–Ag nanocomposite exhibits a purely faradic behaviour using nickel foam as a current collector thus suggests the prepared nanocomposite as a battery electrode material. The nanocomposite reports a maximum specific capacity of 1428 C g‑1 and excellent cyclic stability up-to 5000 cycles.

  16. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air... exposures to airborne radioactive material. (b) The estimation of internal dose shall be based on...

  17. Development of a southern oceanic air standard reference material.

    PubMed

    Rhoderick, George C; Kelley, Michael E; Miller, Walter R; Brailsford, Gordon; Possolo, Antonio

    2016-02-01

    In 2009, the United States Congress charged the National Institute of Standards and Technology (NIST) with supporting climate change research. As part of this effort, the Gas Sensing Metrology Group at NIST began developing new gas standard mixtures for greenhouse gas mixtures relevant to atmospheric measurements. Suites of gravimetrically prepared primary standard mixtures (PSMs) were prepared at ambient concentration levels for carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in a dry-air balance. In parallel, 30 gas cylinders were filled, by the National Institute of Water and Atmospheric Research (NIWA) in Wellington, New Zealand, to high pressure from pristine southern oceanic air at Baring Head, New Zealand, and shipped to NIST. Using spectroscopic instrumentation, NIST analyzed the 30 cylinder samples for mole fractions of CO2, CH4, and N2O. Certified values were assigned to these mixtures by calibrating the instrumentation with the PSM suites that were recently developed at NIST. These mixtures became NIST Standard Reference Material (SRM) 1721 Southern Oceanic Air and are certified for ambient mole fraction, the first of their kind for NIST. The relative expanded uncertainties corresponding to coverage intervals with 95% probability are no larger than 0.06% of the certified values, representing the smallest uncertainties to date ever assigned to an NIST gas SRM.

  18. Development of Novel Electrode Materials for the Electrocatalysis of Oxygen-Transfer and Hydrogen-Transfer Reactions

    SciTech Connect

    Simpson, Brett Kimball

    2002-01-01

    Throughout this thesis, the fundamental aspects involved in the electrocatalysis of anodic O-transfer reactions and cathodic H-transfer reactions have been studied. The investigation into anodic O-transfer reactions at undoped and Fe(III)[doped MnO2 films] revealed that MnO2 film electrodes prepared by a cycling voltammetry deposition show improved response for DMSO oxidation at the film electrodes vs. the Au substrate. Doping of the MnO2 films with Fe(III) further enhanced electrode activity. Reasons for this increase are believed to involve the adsorption of DMSO by the Fe(III) sites. The investigation into anodic O-transfer reactions at undoped and Fe(III)-doped RuO2 films showed that the Fe(III)-doped RuO2-film electrodes are applicable for anodic detection of sulfur compounds. The Fe(III) sites in the Fe-RuO2 films are speculated to act as adsorption sites for the sulfur species while the Ru(IV) sites function for anodic discharge of H2O to generate the adsorbed OH species. The investigation into cathodic H-transfer reactions, specifically nitrate reduction, at various pure metals and their alloys demonstrated that the incorporation of metals into alloy materials can create a material that exhibits bifunctional properties for the various steps involved in the overall nitrate reduction reaction. The Sb10Sn20Ti70, Cu63Ni37 and Cu25Ni75 alloy electrodes exhibited improved activity for nitrate reduction as compared to their pure component metals. The Cu63Ni37 alloy displayed the highest activity for nitrate reduction. The final investigation was a detailed study of the electrocatalytic activity of cathodic H-transfer reactions (nitrate reduction) at various compositions of Cu-Ni alloy electrodes. Voltammetric response for NO3- at the Cu-Ni alloy electrode is superior to

  19. A novel high capacity positive electrode material with tunnel-type structure for aqueous sodium-ion batteries

    SciTech Connect

    Wang, Yuesheng; Mu, Linqin; Liu, Jue; Yang, Zhenzhong; Yu, Xiqian; Gu, Lin; Hu, Yong -Sheng; Li, Hong; Yang, Xiao -Qing; Chen, Liquan; Huang, Xuejie

    2015-08-06

    In this study, aqueous sodium-ion batteries have shown desired properties of high safety characteristics and low-cost for large-scale energy storage applications such as smart grid, because of the abundant sodium resources as well as the inherently safer aqueous electrolytes. Among various Na insertion electrode materials, tunnel-type Na0.44MnO2 has been widely investigated as a positive electrode for aqueous sodium-ion batteries. However, the low achievable capacity hinders its practical applications. Here we report a novel sodium rich tunnel-type positive material with a nominal composition of Na0.66[Mn0.66Ti0.34]O2. The tunnel-type structure of Na0.44MnO2 obtained for this compound was confirmed by XRD and atomic-scale STEM/EELS. When cycled as positive electrode in full cells using NaTi2(PO4)3/C as negative electrode in 1M Na2SO4 aqueous electrolyte, this material shows the highest capacity of 76 mAh g-1 among the Na insertion oxides with an average operating voltage of 1.2 V at a current rate of 2C. These results demonstrate that Na0.66[Mn0.66Ti0.34]O2 is a promising positive electrode material for rechargeable aqueous sodium-ion batteries.

  20. In Situ Powder Diffraction Studies of Electrode Materials in Rechargeable Batteries.

    PubMed

    Sharma, Neeraj; Pang, Wei Kong; Guo, Zaiping; Peterson, Vanessa K

    2015-09-07

    The ability to directly track the charge carrier in a battery as it inserts/extracts from an electrode during charge/discharge provides unparalleled insight for researchers into the working mechanism of the device. This crystallographic-electrochemical information can be used to design new materials or modify electrochemical conditions to improve battery performance characteristics, such as lifetime. Critical to collecting operando data used to obtain such information in situ while a battery functions are X-ray and neutron diffractometers with sufficient spatial and temporal resolution to capture complex and subtle structural changes. The number of operando battery experiments has dramatically increased in recent years, particularly those involving neutron powder diffraction. Herein, the importance of structure-property relationships to understanding battery function, why in situ experimentation is critical to this, and the types of experiments and electrochemical cells required to obtain such information are described. For each battery type, selected research that showcases the power of in situ and operando diffraction experiments to understand battery function is highlighted and future opportunities for such experiments are discussed. The intention is to encourage researchers to use in situ and operando techniques and to provide a concise overview of this area of research.

  1. Solid Liquid Interdiffusion Bonding of Zn4Sb3 Thermoelectric Material with Cu Electrode

    NASA Astrophysics Data System (ADS)

    Lin, Y. C.; Lee, K. T.; Hwang, J. D.; Chu, H. S.; Hsu, C. C.; Chen, S. C.; Chuang, T. H.

    2016-10-01

    The ZnSb intermetallic compound may have thermoelectric applications because it is low in cost and environmentally friendly. In this study, a Zn4Sb3 thermoelectric element coated with a Ni barrier layer and a Ag reaction layer was bonded with a Ag-coated Cu electrode using a Ag/Sn/Ag solid-liquid interdiffusion bonding process. The results indicated that a Ni5Zn21 intermetallic phase formed easily at the Zn4Sb3/Ni interface, leading to sound adhesion. In addition, Sn film was found to react completely with the Ag layer to form a Ag3Sn intermetallic layer having a melting point of 480°C. The resulting Zn4Sb3 thermoelectric module can be applied at the optimized operation temperature (400°C) of Zn4Sb3 material as a thermoelectric element. The bonding strengths ranged from 14.9 MPa to 25.0 MPa, and shear tests revealed that the Zn4Sb3/Cu-joints fractured through the interior of the thermoelectric elements.

  2. Sulfonated graphene oxide and its nanocomposites with electroactive conjugated polymer as effective pseudocapacitor electrode materials.

    PubMed

    Ehsani, A; Kowsari, E; Boorboor Ajdari, F; Safari, R; Mohammad Shiri, H

    2017-07-01

    In this work, we synthesized amine functionalized graphene oxide (GOA), by using of 1-methyl, 3-butyl Imidazole ionic liquid, triphenylphosphine, 1,6-diamino hexane in DMSO medium. Afterward, dried GOA used for sulfonated graphene oxide (GOS). For improving electrochemical properties of the poly ortho aminophenol (POAP), we fabricated POAP/GOS films by electro-polymerization of POAP in the presence of GOS to serve as the active electrode for electrochemical supercapacitor. Different electrochemical methods including galvanostatic charge-discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy are carried out in order to investigate the performance of the system. Finally, the local charge and energy transfer of the molecular system is calculated, using DFT/AIM theories. Results show that the oxygen and nitrogen atoms of phenyl (Ph)/(Ph-OH) rings and -Ph-CO-N-R-N-R″ -SO3H ended functional group, play domain role in intra-molecular charge and energy transfer. The major aim of this computational study method is to propose or effective design electro-chemical molecular systems having different atomic basins/functional groups response (sensitivities) to external voltage. This work introduces new most efficient materials for electrochemical redox capacitors with advantages including ease synthesis, high active surface area and stability in an aqueous electrolyte.

  3. Sensitive determination of carbendazim in orange juice by electrode modified with hybrid material.

    PubMed

    Razzino, Claudia A; Sgobbi, Lívia F; Canevari, Thiago C; Cancino, Juliana; Machado, Sergio A S

    2015-03-01

    This paper describes the application of a glassy carbon electrode modified with a thin film of mesoporous silica/multiwalled carbon nanotubes for voltammetric determination of the fungicide carbendazim (CBZ). The hybrid material, (SiO2/MWCNT), was obtained by a sol-gel process using HF as the catalyst. The amperometric response to CBZ was measured at +0.73 V vs. Ag/AgCl by square wave voltammetry at pH 8.0. SiO2/MWCNT/GCE responded to CBZ in the linear range from 0.2 to 4.0 μmol L(-1). The calculated detection limit was 0.056 μmol L(-1), obtained using statistical methods. The SiO2/MWCNT/GCE sensor presented as the main characteristics high sensitivity, low detection limit and robustness, allowing CBZ determination in untreated real samples. In addition, this strategy afforded remarkable selectivity for CBZ against ascorbic and citric acid which are the main compounds of the orange juice. The excellent sensitivity and selectivity yielded feasible application for CBZ detection in orange juice sample.

  4. Studies on Supercapacitor Electrode Material from Activated Lignin-Derived Mesoporous Carbon

    SciTech Connect

    Saha, Dipendu; Li, Yunchao; Bi, Zhonghe; Chen, Jihua; Keum, Jong Kahk; Hensley, Dale K; Grappe, Hippolyte A.; Meyer III, Harry M; Dai, Sheng; Paranthaman, Mariappan Parans; Naskar, Amit K

    2014-01-01

    We synthesized mesoporous carbon from pre-cross-linked lignin gel impregnated with a surfactant as the pore-forming agent, and then activated the carbon through physical and chemical methods to obtain activated mesoporous carbon. The activated mesoporous carbons exhibited 1.5- to 6-fold increases in porosity with a maximum BET specific surface area of 1148 m2/g and a pore volume of 1.0 cm3/g. Slow physical activation helped retain dominant mesoporosity; however, aggressive chemical activation caused some loss of the mesopore volume fraction. Plots of cyclic voltammetric data with the capacitor electrode made from these carbons showed an almost rectangular curve depicting the behavior of ideal double-layer capacitance. Although the pristine mesoporous carbon exhibited the same range of surface-area-based capacitance as that of other known carbon-based supercapacitors, activation decreased the surface-area-based specific capacitance and increased the gravimetric-specific capacitance of the mesoporous carbons. Surface activation lowered bulk density and electrical conductivity. Warburg impedance as a vertical tail in the lower frequency domain of Nyquist plots supported good supercapacitor behavior for the activated mesoporous carbons. Our work demonstrated that biomass-derived mesoporous carbon materials continue to show potential for use in specific electrochemical applications.

  5. Catechol-modified activated carbon prepared by the diazonium chemistry for application as active electrode material in electrochemical capacitor.

    PubMed

    Pognon, Grégory; Cougnon, Charles; Mayilukila, Dilungane; Bélanger, Daniel

    2012-08-01

    Activated carbon (Black Pearls 2000) modified with electroactive catechol groups was evaluated for charge storage application as active composite electrode material in an aqueous electrochemical capacitor. High surface area Black Pearls 2000 carbon was functionalized by introduction of catechol groups by spontaneous reduction of catechol diazonium ions in situ prepared in aqueous solution from the corresponding amine. Change in the specific surface area and pore texture of the carbon following grafting was monitored by nitrogen gas adsorption measurements. The electrochemical properties and the chemical composition of the catechol-modified carbon electrodes were investigated by cyclic voltammetry. Such carbon-modified electrode combines well the faradaic capacitance, originating from the redox activity of the surface immobilized catechol groups, to the electrochemical double layer capacitance of the high surface area Black Pearls carbon. Due to the faradaic contribution, the catechol-modified electrode exhibits a higher specific capacitance (250 F/g) than pristine carbon (150 F/g) over a potential range of -0.4 to 0.75 V in 1 M H(2)SO(4). The stability of the modified electrode evaluated by long-time charge/discharge cycling revealed a low decrease of the capacitance of the catechol-modified carbon due to the loss of the catechol redox activity. Nonetheless, it was demonstrated that the benefit of redox groups persists for 10, 000 constant current charge/discharge cycles.

  6. Borophene as an extremely high capacity electrode material for Li-ion and Na-ion batteries.

    PubMed

    Zhang, Xiaoming; Hu, Junping; Cheng, Yingchun; Yang, Hui Ying; Yao, Yugui; Yang, Shengyuan A

    2016-08-18

    "Two-dimensional (2D) materials as electrodes" is believed to be the trend for future Li-ion and Na-ion battery technologies. Here, by using first-principles methods, we predict that the recently reported borophene (2D boron sheets) can serve as an ideal electrode material with high electrochemical performance for both Li-ion and Na-ion batteries. The calculations are performed on two experimentally stable borophene structures, namely β12 and χ3 structures. The optimized Li and Na adsorption sites are identified, and the host materials are found to maintain good electric conductivity before and after adsorption. Besides advantages including small diffusion barriers and low average open-circuit voltages, most remarkably, the storage capacity can be as high as 1984 mA h g(-1) in β12 borophene and 1240 mA h g(-1) in χ3 borophene for both Li and Na, which are several times higher than the commercial graphite electrode and are the highest among all the 2D materials discovered to date. Our results highly support that borophenes can be appealing anode materials for both Li-ion and Na-ion batteries with extremely high power density.

  7. Bioelectricity generation in continuously-fed microbial fuel cell: effects of anode electrode material and hydraulic retention time.

    PubMed

    Akman, Dilek; Cirik, Kevser; Ozdemir, Sebnem; Ozkaya, Bestamin; Cinar, Ozer

    2013-12-01

    The main aim of this study is to investigate the bioelectricity production in continuously-fed dual chambered microbial fuel cell (MFC). Initially, MFC was operated with different anode electrode material at constant hydraulic retention time (HRT) of 2d to evaluate the effect of electrode material on electricity production. Pt electrode yielded about 642 mW/m(2) power density, which was 4 times higher than that of the MFC with the mixed metal oxide titanium (Ti-TiO2). Further, MFC equipped with Pt electrode was operated at varying HRT (2-0.5d). The power density generation increased with decreasing HRT, corresponding to 1313 mW/m(2) which was maximum value obtained during this study. Additionally, decreasing HRT from 2 to 0.5d resulted in increasing effluent dissolved organic carbon (DOC) concentration from 1.92 g/L to 2.23 g/L, corresponding to DOC removal efficiencies of 46% and 38%, respectively.

  8. An adhesive conducting electrode material based on commercial mesoporous titanium dioxide as a support for Horseradish peroxidase for bioelectrochemical applications.

    PubMed

    Rahemi, Vanoushe; Trashin, Stanislav; Meynen, Vera; De Wael, Karolien

    2016-01-01

    An adhesive conducting electrode material containing of graphite, biocompatible ion exchange polymer nafion(®) and commercial mesoporous TiO2 impregnated with horseradish peroxidase (HRP) is prepared and characterized by amperometric, UV-vis and N2 sorption methods. The factors influencing the performance of the resulting biosensor are studied in detail. The optimal electrode material consists of 45% graphite, 50% impregnated HRP-TiO2 and 5% nafion(®). The optimum conditions for H2O2 reduction are an applied potential of -0.3 V and 0.1 mM hydroquinone. Sensitivity and limit of detection in the optimum conditions are 1 A M(-1) cm(-2) and 1 µM correspondingly. The N2 sorption results show that the pore volume of TiO2 decreases sharply upon adsorption of HRP. The preparation process of the proposed enzyme electrode is straightforward and potentially can be used for preparation of carbon paste electrodes for bioelectrochemical detections.

  9. Impedance spectroscopy study of a catechol-modified activated carbon electrode as active material in electrochemical capacitor

    NASA Astrophysics Data System (ADS)

    Cougnon, C.; Lebègue, E.; Pognon, G.

    2015-01-01

    Modified activated carbon (Norit S-50) electrodes with electrochemical double layer (EDL) capacitance and redox capacitance contributions to the electric charge storage were tested in 1 M H2SO4 to quantify the benefit and the limitation of the surface redox reactions on the electrochemical performances of the resulting pseudo-capacitive materials. The electrochemical performances of an electrochemically anodized carbon electrode and a catechol-modified carbon electrode, which make use both EDL capacitance of the porous structure of the carbon and redox capacitance, were compared to the performances obtained for the pristine carbon. Nitrogen gas adsorption measurements have been used for studying the impact of the grafting on the BET surface area, pore size distribution, pore volume and average pore diameter. The electrochemical behavior of carbon materials was studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The EIS data were discussed by using a complex capacitance model that allows defining the characteristic time constant, the global capacitance and the frequency at which the maximum charge stored is reached. The EIS measurements were achieved at different dc potential values where a redox activity occurs and the evolution of the capacitance and the capacitive relaxation time with the electrode potential are presented. Realistic galvanostatic charge/discharge measurements performed at different current rates corroborate the results obtained by impedance.

  10. Rapid synthesis of monodispersed highly porous spinel nickel cobaltite (NiCo2O4) electrode material for supercapacitors

    NASA Astrophysics Data System (ADS)

    Naveen, A. Nirmalesh; Selladurai, S.

    2015-06-01

    Monodispersed highly porous spinel nickel cobaltite electrode material was successfully synthesized in a short time using combustion technique. Single phase cubic nature of the spinel nickel cobaltite with average crystallite size of 24 nm was determined from X-ray diffraction study. Functional groups present in the compound were determined from FTIR study and it further confirms the spinel formation. FESEM images reveal the porous nature of the prepared material and uniform size distribution of the particles. Electrochemical evaluation was performed using Cyclic Voltammetry (CV) technique, Chronopotentiometry (CP) and Electrochemical Impedance Spectroscopy (EIS). Results reveal the typical pseudocapacitive behaviour of the material. Maximum capacitance of 754 F/g was calculated at the scan rate of 5 mV/s, high capacitance was due to the unique porous morphology of the electrode. Nyquist plot depicts the low resistance and good electrical conductivity of nickel cobaltite. It has been found that nickel cobaltite prepared by this typical method will be a potential electrode material for supercapcitor application.

  11. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air concentration (DAC) values given in appendices A and C of this part shall be used in the control of...

  12. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air concentration (DAC) values given in appendices A and C of this part shall be used in the control of...

  13. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air concentration (DAC) values given in appendices A and C of this part shall be used in the control of...

  14. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air concentration (DAC) values given in appendices A and C of this part shall be used in the control of...

  15. Iron-Air Rechargeable Battery

    NASA Technical Reports Server (NTRS)

    Narayan, Sri R. (Inventor); Prakash, G.K. Surya (Inventor); Kindler, Andrew (Inventor)

    2014-01-01

    Embodiments include an iron-air rechargeable battery having a composite electrode including an iron electrode and a hydrogen electrode integrated therewith. An air electrode is spaced from the iron electrode and an electrolyte is provided in contact with the air electrode and the iron electrodes. Various additives and catalysts are disclosed with respect to the iron electrode, air electrode, and electrolyte for increasing battery efficiency and cycle life.

  16. Generation of large-scale, barrier-free diffuse plasmas in air at atmospheric pressure using array wire electrodes and nanosecond high-voltage pulses

    SciTech Connect

    Teng, Yun; Li, Lee Liu, Yun-Long; Liu, Lun; Liu, Minghai

    2014-10-15

    This paper introduces a method to generate large-scale diffuse plasmas by using a repetition nanosecond pulse generator and a parallel array wire-electrode configuration. We investigated barrier-free diffuse plasmas produced in the open air in parallel and cross-parallel array line-line electrode configurations. We found that, when the distance between the wire-electrode pair is small, the discharges were almost extinguished. Also, glow-like diffuse plasmas with little discharge weakening were obtained in an appropriate range of line-line distances and with a cathode-grounding cross-electrode configuration. As an example, we produced a large-scale, stable diffuse plasma with volumes as large as 18 × 15 × 15 cm{sup 3}, and this discharge region can be further expanded. Additionally, using optical and electrical measurements, we showed that the electron temperature was higher than the gas temperature, which was almost the same as room temperature. Also, an array of electrode configuration with more wire electrodes had helped to prevent the transition from diffuse discharge to arc discharge. Comparing the current waveforms of configurations with 1 cell and 9 cells, we found that adding cells significantly increased the conduction current and the electrical energy delivered in the electrode gaps.

  17. Generation of large-scale, barrier-free diffuse plasmas in air at atmospheric pressure using array wire electrodes and nanosecond high-voltage pulses

    NASA Astrophysics Data System (ADS)

    Teng, Yun; Li, Lee; Liu, Yun-Long; Liu, Lun; Liu, Minghai

    2014-10-01

    This paper introduces a method to generate large-scale diffuse plasmas by using a repetition nanosecond pulse generator and a parallel array wire-electrode configuration. We investigated barrier-free diffuse plasmas produced in the open air in parallel and cross-parallel array line-line electrode configurations. We found that, when the distance between the wire-electrode pair is small, the discharges were almost extinguished. Also, glow-like diffuse plasmas with little discharge weakening were obtained in an appropriate range of line-line distances and with a cathode-grounding cross-electrode configuration. As an example, we produced a large-scale, stable diffuse plasma with volumes as large as 18 × 15 × 15 cm3, and this discharge region can be further expanded. Additionally, using optical and electrical measurements, we showed that the electron temperature was higher than the gas temperature, which was almost the same as room temperature. Also, an array of electrode configuration with more wire electrodes had helped to prevent the transition from diffuse discharge to arc discharge. Comparing the current waveforms of configurations with 1 cell and 9 cells, we found that adding cells significantly increased the conduction current and the electrical energy delivered in the electrode gaps.

  18. Development of a Northern Continental Air Standard Reference Material.

    PubMed

    Rhoderick, George C; Kitzis, Duane R; Kelley, Michael E; Miller, Walter R; Hall, Bradley D; Dlugokencky, Edward J; Tans, Pieter P; Possolo, Antonio; Carney, Jennifer

    2016-03-15

    The National Institute of Standards and Technology (NIST) recently began to develop standard mixtures of greenhouse gases as part of a broad program mandated by the 2009 United States Congress to support research in climate change. To this end, NIST developed suites of gravimetrically assigned primary standard mixtures (PSMs) comprising carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in a dry-natural air balance at ambient mole fraction levels. In parallel, the National Oceanic and Atmospheric Administration (NOAA) in Boulder, Colorado, charged 30 aluminum gas cylinders with northern hemisphere air at Niwot Ridge, Colorado. These mixtures, which constitute NIST Standard Reference Material (SRM) 1720 Northern Continental Air, were certified by NIST for ambient mole fractions of CO2, CH4, and N2O relative to NIST PSMs. NOAA-assigned values are also provided as information in support of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Program for CO2, CH4, and N2O, since NOAA serves as the WMO Central Calibration Laboratory (CCL) for CO2, CH4, and N2O. Relative expanded uncertainties at the 95% confidence interval are <±0.06% of the certified values for CO2 and N2O and <0.2% for CH4, which represents the smallest relative uncertainties specified to date for a gaseous SRM produced by NIST. Agreement between the NOAA (WMO/GAW) and NIST values based on their respective calibration standards suites is within 0.05%, 0.13%, and 0.06% for CO2, CH4, and N2O, respectively. This collaborative development effort also represents the first of its kind for a gaseous SRM developed by NIST.

  19. HSPES membrane electrode assembly

    NASA Technical Reports Server (NTRS)

    Kindler, Andrew (Inventor); Yen, Shiao-Ping (Inventor)

    2000-01-01

    An improved fuel cell electrode, as well as fuel cells and membrane electrode assemblies that include such an electrode, in which the electrode includes a backing layer having a sintered layer thereon, and a non-sintered free-catalyst layer. The invention also features a method of forming the electrode by sintering a backing material with a catalyst material and then applying a free-catalyst layer.

  20. Influence Of Adsorbent Materials On Streamers Propagation In Air And Induced Chemical Efficiency

    NASA Astrophysics Data System (ADS)

    Guaitella, O.; Marinov, I.; Dong, B.; Rousseau, A.

    2010-07-01

    Atmospheric pressure plasmas are now used in many different applications from odor treatment to biomedicine as well as surface functionalization or molecules synthesis. Dielectric barrier discharge (DBD) is a widely used source for this application because of safety reasons, low energetic cost, and randomly distributed treatment over the whole reac- tor volume (Kogelschatz 2003, Kim 2004, Roth et al. 1998, Guaitella et al. 2008). DBD used for air treatment of volatile organic compounds (VOC) produce filamentary plasmas which have to be combined with porous catalytic surfaces. Filaments have then to ramp in contact with a complex dielectric surface, or even go through small diameter holes which could constraint the filaments. As a consequence, the breakdown, and the development of the filaments could be strongly modified by the surface, and the species adsorbed on it. The aim of this work is to discriminate in the plasma/catalyst coupling performed for VOC abatement in DBD, what is a consequence of surface chemistry on the adsorbent ma- terial from what is due to modifications of filaments behavior. The same dielectric surfaces (pyrex, quartz, TiO2 and Al2O3) are then used in different experimental setups. A classical study on VOC removal is first performed downstream a DBD with or without catalyst. These results are compared to surface chemistry directly measured onto the surfaces by DRIFT method. Then, the physical properties of filaments generated on the same surfaces are analyzed with three different experiments. A double electrode surface DBD discharge allows studying the influence of photo-desorption of charges stored onto the surface on the filament breakdown. Then the dynamic of charge deposition is obtained by electrical measurement on a devoted multiple ground electrodes reactor. Finally, the velocity and electric field are measured for air streamers forced to propagate inside capillary tube. All these experiments performed with the same dielectric

  1. 3D Interconnected Electrode Materials with Ultrahigh Areal Sulfur Loading for Li-S Batteries.

    PubMed

    Fang, Ruopian; Zhao, Shiyong; Hou, Pengxiang; Cheng, Min; Wang, Shaogang; Cheng, Hui-Ming; Liu, Chang; Li, Feng

    2016-05-01

    Sulfur electrodes based on a 3D integrated hollow carbon fiber foam (HCFF) are synthesized with high sulfur loadings of 6.2-21.2 mg cm(-2) . Benefiting from the high electrolyte absorbability of the HCFF and the multiple conductive channels, the obtained electrode demonstrates excellent cycling stability and a high areal capacity of 23.32 mAh cm(-2) , showing great promise in commercially viable Li-S batteries.

  2. An effect of the electrode material on space charge relaxation in ferroelectric copolymers of vinylidene fluoride

    SciTech Connect

    Kochervinskii, Valentin Pavlov, Alexey; Pakuro, Natalia; Bessonova, Natalia; Shmakova, Nina; Malyshkina, Inna; Bedin, Sergey

    2015-12-28

    Processes of relaxation of space charges formed by impurities carriers in isotropic films of vinylidene fluoride and tetrafluoroethylene copolymers of the composition 71/29 and 94/6 were studied. Al and Au symmetric electrodes deposited by evaporation in vacuum have been used. In the case of Al electrodes at temperatures above 100 °C, giant low frequency dielectric dispersion was observed, while it is absent in films with Au electrodes. Causes of this phenomenon were studied by the X-ray photoelectron spectroscopy. It was shown that at Al deposition, new functional groups, such as Al-C, Al-F, and Al{sub 2}O{sub 3}, which are not characteristic of the copolymer film surface, formed. They were supposed to be traps for impurity carriers and because of this the electrode became partially blocked. This led to appearance of the giant electrode polarization on the metal-polymer boundary, which did not take place in the case of Au electrodes. Parameters of the Au4f line for the copolymer with different contents of fluorine atoms in the chain were analyzed. An increase in the number of these atoms was shown to result in the line shift to higher energies. This phenomenon was associated with an increase in the shift of the electron density from Au atoms to the F ones which has a high affinity to electrons.

  3. Graphene coated with controllable N-doped carbon layer by molecular layer deposition as electrode materials for supercapacitors

    NASA Astrophysics Data System (ADS)

    Chen, Yao; Gao, Zhe; Zhang, Bin; Zhao, Shichao; Qin, Yong

    2016-05-01

    In this work, graphene is coated with nitrogen-doped carbon layer, which is produced by a carbonization process of aromatic polyimide (PI) films deposited on the surfaces of graphene by molecular layer deposition (MLD). The utilization of MLD not only allows uniform coating of PI layers on the surfaces of pristine graphene without any surface treatment, but also enables homogenous dispersion of doped nitrogen atoms in the carbonized products. The as-prepared N-doped carbon layer coated graphene (NC-G) exhibited remarkable capacitance performance as electrode materials for supercapacitor, showing a high specific capacitance of 290.2 F g-1 at current density of 1 A g-1 in 6 M KOH aqueous electrolyte, meanwhile maintaining good rate performance and stable cycle capability. The NC-G synthesized by this way represents an alternative promising candidate as electrode material for supercapacitors.

  4. Hierarchically ordered mesoporous carbon/graphene composites as supercapacitor electrode materials.

    PubMed

    Song, Yanjie; Li, Zhu; Guo, Kunkun; Shao, Ting

    2016-08-25

    Hierarchically ordered mesoporous carbon/graphene (OMC/G) composites have been fabricated by means of a solvent-evaporation-induced self-assembly (EISA) method. The structures of these composites are characterized by X-ray diffraction, transmission electron microscopy, Raman spectroscopy and nitrogen adsorption-desorption at 77 K. These results indicate that OMC/G composites possess the hierarchically ordered hexagonal p6mm mesostructure with the lattice unit parameter and pore diameter close to 10 nm and 3 nm, respectively. The specific surface area of OMC/G composites after KOH activation is high up to 2109.2 m(2) g(-1), which is significantly greater than OMC after activation (1474.6 m(2) g(-1)). Subsequently, the resulting OMC/G composites as supercapacitor electrode materials exhibit an outstanding capacitance as high as 329.5 F g(-1) in 6 M KOH electrolyte at a current density of 0.5 A g(-1), which is much higher than both OMC (234.2 F g(-1)) and a sample made by mechanical mixing of OMC with graphene (217.7 F g(-1)). In addition, the obtained OMC/G composites display good cyclic stability, and the final capacitance retention is approximately 96% after 5000 cycles. These ordered mesopores in the OMC/G composites are beneficial to the accessibility and rapid diffusion of the electrolyte, while graphene in OMC/G composites can also facilitate the transport of electrons during the processes of charging and discharging owing to its high conductivity, thereby leading to an excellent energy storage performance. The method demonstrated in this work would open up a new route to design and develop graphene-based architectures for supercapacitor applications.

  5. Layer by Layer Ex-Situ Deposited Cobalt-Manganese Oxide as Composite Electrode Material for Electrochemical Capacitor

    PubMed Central

    Rusi; Chan, P. Y.; Majid, S. R.

    2015-01-01

    The composite metal oxide electrode films were fabricated using ex situ electrodeposition method with further heating treatment at 300°C. The obtained composite metal oxide film had a spherical structure with mass loading from 0.13 to 0.21 mg cm-2. The structure and elements of the composite was investigated using X-ray diffraction (XRD) and energy dispersive X-ray (EDX). The electrochemical performance of different composite metal oxides was studied by cyclic voltammetry (CV) and galvanostatic charge-discharge (CD). As an active electrode material for a supercapacitor, the Co-Mn composite electrode exhibits a specific capacitance of 285 Fg-1 at current density of 1.85 Ag-1 in 0.5M Na2SO4 electrolyte. The best composite electrode, Co-Mn electrode was then further studied in various electrolytes (i.e., 0.5M KOH and 0.5M KOH/0.04M K3Fe(CN) 6 electrolytes). The pseudocapacitive nature of the material of Co-Mn lead to a high specific capacitance of 2.2 x 103 Fg-1 and an energy density of 309 Whkg-1 in a 0.5MKOH/0.04MK3Fe(CN) 6 electrolyte at a current density of 10 Ag-1. The specific capacitance retention obtained 67% of its initial value after 750 cycles. The results indicate that the ex situ deposited composite metal oxide nanoparticles have promising potential in future practical applications. PMID:26158447

  6. Correction of the power law of ac conductivity in ion-conducting materials due to the electrode polarization effect.

    PubMed

    Khamzin, A A; Popov, I I; Nigmatullin, R R

    2014-03-01

    Based on the supposition related to fractal nature of transport processes in ion-conducting materials, an expression for the low-frequency ac conductivity dependence was derived. This expression for the ac conductivity generalizes the power-law dependence and gives a possibility to take into account the influence of the electrode polarization effect. The ac conductivity expression obtained is in excellent agreement with experimental data for a wide frequency range.

  7. Wurtzite copper-zinc-tin sulfide as a superior counter electrode material for dye-sensitized solar cells

    PubMed Central

    2013-01-01

    Wurtzite and kesterite Cu2ZnSnS4 (CZTS) nanocrystals were employed as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). Compared to kesterite CZTS, the wurtzite CZTS exhibited higher electrocatalytic activity for catalyzing reduction of iodide electrolyte and better conductivity. Accordingly, the DSSC with wurtzite CZTS CE generated higher power conversion efficiency (6.89%) than that of Pt (6.23%) and kesterite CZTS (4.89%) CEs. PMID:24191954

  8. Transition-Metal Carbodiimides as Molecular Negative Electrode Materials for Lithium- and Sodium-Ion Batteries with Excellent Cycling Properties.

    PubMed

    Sougrati, Moulay T; Darwiche, Ali; Liu, Xiaohiu; Mahmoud, Abdelfattah; Hermann, Raphael P; Jouen, Samuel; Monconduit, Laure; Dronskowski, Richard; Stievano, Lorenzo

    2016-04-11

    We report evidence for the electrochemical activity of transition-metal carbodiimides versus lithium and sodium. In particular, iron carbodiimide, FeNCN, can be efficiently used as negative electrode material for alkali-metal-ion batteries, similar to its oxide analogue FeO. Based on (57)Fe Mössbauer and infrared spectroscopy (IR) data, the electrochemical reaction mechanism can be explained by the reversible transformation of the Fe-NCN into Li/Na-NCN bonds during discharge and charge. These new electrode materials exhibit higher capacity compared to well-established negative electrode references such as graphite or hard carbon. Contrary to its oxide analogue, iron carbodiimide does not require heavy treatments (such as nanoscale tailoring, sophisticated textures, or coating) to obtain long cycle life with current density as high as 9 A g(-1) for hundreds of charge-discharge cycles. Similar to the iron compound, several other transition-metal carbodiimides M(x)(NCN)y with M=Mn, Cr, Zn can cycle successfully versus lithium and sodium. Their electrochemical activity and performance open the way to the design of a novel family of anode materials.

  9. Transition-Metal Carbodiimides as Molecular Negative Electrode Materials for Lithium- and Sodium-Ion Batteries with Excellent Cycling Properties

    DOE PAGES

    Sougrati, Moulay T.; Darwiche, Ali; Liu, Xiaohiu; ...

    2016-03-16

    Here we report evidence for the electrochemical activity of transition-metal carbodiimides versus lithium and sodium. In particular, iron carbodiimide, FeNCN, can be efficiently used as a negative electrode material for alkali-metal-ion batteries, similar to its oxide analogue FeO. Based on 57Fe M ssbauer and infrared spectroscopy (IR) data, the electrochemical reaction mechanism can be explained by the reversible transformation of the Fe NCN into Li/Na NCN bonds during discharge and charge. These new electrode materials exhibit higher capacity compared to well-established negative electrode references such as graphite or hard carbon. Contrary to its oxide analogue, iron carbodiimide does not requiremore » heavy treatments (nanoscale tailoring, sophisticated textures, coating etc.) to obtain long cycle life with density current as high as 9 A/g-1 for hundreds of charge/discharge cycles. Similar to the iron compound, several other transition-metal carbodiimides Mx(NCN)y with M = Mn, Cr, Zn can cycle successfully versus lithium and sodium. Ultimately, their electrochemical activity and performances open the way to the design of a novel family of anode materials.« less

  10. Transition-Metal Carbodiimides as Molecular Negative Electrode Materials for Lithium- and Sodium-Ion Batteries with Excellent Cycling Properties

    SciTech Connect

    Sougrati, Moulay T.; Darwiche, Ali; Liu, Xiaohiu; Mahmoud, Abdelfattah; Hermann, Raphael P.; Jouen, Samuel; Monconduit, Laure; Dronskowski, Richard; Stievano, Lorenzo

    2016-03-16

    Here we report evidence for the electrochemical activity of transition-metal carbodiimides versus lithium and sodium. In particular, iron carbodiimide, FeNCN, can be efficiently used as a negative electrode material for alkali-metal-ion batteries, similar to its oxide analogue FeO. Based on 57Fe M ssbauer and infrared spectroscopy (IR) data, the electrochemical reaction mechanism can be explained by the reversible transformation of the Fe NCN into Li/Na NCN bonds during discharge and charge. These new electrode materials exhibit higher capacity compared to well-established negative electrode references such as graphite or hard carbon. Contrary to its oxide analogue, iron carbodiimide does not require heavy treatments (nanoscale tailoring, sophisticated textures, coating etc.) to obtain long cycle life with density current as high as 9 A/g-1 for hundreds of charge/discharge cycles. Similar to the iron compound, several other transition-metal carbodiimides Mx(NCN)y with M = Mn, Cr, Zn can cycle successfully versus lithium and sodium. Ultimately, their electrochemical activity and performances open the way to the design of a novel family of anode materials.

  11. Preparation and photoelectrocatalytic performance of N-doped TiO2/NaY zeolite membrane composite electrode material.

    PubMed

    Cheng, Zhi-Lin; Han, Shuai

    2016-01-01

    A novel composite electrode material based on a N-doped TiO2-loaded NaY zeolite membrane (N-doped TiO2/NaY zeolite membrane) for photoelectrocatalysis was presented. X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible (UV-vis) and X-ray photoelectron spectroscopy (XPS) characterization techniques were used to analyze the structure of the N-doped TiO2/NaY zeolite membrane. The XRD and SEM results verified that the N-doped TiO2 nanoparticles with the size of ca. 20 nm have been successfully loaded on the porous stainless steel-supported NaY zeolite membrane. The UV-vis result showed that the N-doped TiO2/NaY zeolite membrane exhibited a more obvious red-shift than that of N-TiO2 nanoparticles. The XPS characterization revealed that the doping of N element into TiO2 was successfully achieved. The photoelectrocatalysis performance of the N-doped TiO2/NaY zeolite membrane composite electrode material was evaluated by phenol removal and also the effects of reaction conditions on the catalytic performance were investigated. Owing to exhibiting an excellent catalytic activity and good recycling stability, the N-doped TiO2/NaY zeolite membrane composite electrode material was of promising application for photoelectrocatalysis in wastewater treatment.

  12. Evaluating biomass-derived hierarchically porous carbon as the positive electrode material for hybrid Na-ion capacitors

    NASA Astrophysics Data System (ADS)

    Chen, Jizhang; Zhou, Xiaoyan; Mei, Changtong; Xu, Junling; Zhou, Shuang; Wong, Ching-Ping

    2017-02-01

    As a promising renewable resource, biomass has several advantages such as wide availability, low cost, and versatility. In this study, we use peanut shell, wheat straw, rice straw, corn stalk, cotton stalk, and soybean stalk as the precursors to synthesize hierarchically porous carbon as the positive electrode material for hybrid Na-ion capacitors, aiming to establish a criterion of choosing suitable biomass precursors. The carbon derived from wood-like cotton stalk has abundant interconnected macropores, high surface area of 1994 m2 g-1, and large pore volume of 1.107 cm3 g-1, thanks to which it exhibits high reversible capacitance of 160.5 F g-1 at 0.2 A g-1 and great rate capability, along with excellent cyclability. The carbonaceous positive electrode material is combined with a Na2Ti2.97Nb0.03O7 negative electrode material to assemble a hybrid Na-ion capacitor, which delivers a high specific energy of 169.4 Wh kg-1 at 120.5 W kg-1, ranking among the best-performed hybrid ion capacitors.

  13. Molybdenum polysulfide chalcogels as high-capacity, anion-redox-driven electrode materials for Li-ion batteries

    SciTech Connect

    Doan-Nguyen, Vicky V. T.; Subrahmanyam, Kota S.; Butala, Megan M.; Gerbec, Jeffrey A.; Islam, Saiful M.; Kanipe, Katherine N.; Wilson, Catrina E.; Balasubramanian, Mahalingam; Wiaderek, Kamila M.; Borkiewicz, Olaf J.; Chapman, Karena W.; Chupas, Peter J.; Moskovits, Martin; Dunn, Bruce S.; Kanatzidis, Mercouri G.; Seshadri, Ram

    2016-11-09

    Sulfur cathodes in conversion reaction batteries offer high gravimetric capacity but suffer from parasitic polysulfide shuttling. We demonstrate here that transition metal chalcogels of approximate formula MoS3.4 achieve a high gravimetric capacity close to 600 mAh g–1 (close to 1000 mAh g–1 on a sulfur basis) as electrode materials for lithium-ion batteries. Transition metal chalcogels are amorphous and comprise polysulfide chains connected by inorganic linkers. The linkers appear to act as a “glue” in the electrode to prevent polysulfide shuttling. The Mo chalcogels function as electrodes in carbonate- and ether-based electrolytes, which further provides evidence of polysulfide solubility not being a limiting issue. We employ X-ray spectroscopy and operando pair distribution function techniques to elucidate the structural evolution of the electrode. Raman and X-ray photoelectron spectroscopy track the chemical moieties that arise during the anion-redox-driven processes. As a result, we find the redox state of Mo remains unchanged across the electrochemical cycling and, correspondingly, the redox is anion-driven.

  14. Molybdenum polysulfide chalcogels as high-capacity, anion-redox-driven electrode materials for Li-ion batteries

    DOE PAGES

    Doan-Nguyen, Vicky V. T.; Subrahmanyam, Kota S.; Butala, Megan M.; ...

    2016-11-09

    Sulfur cathodes in conversion reaction batteries offer high gravimetric capacity but suffer from parasitic polysulfide shuttling. We demonstrate here that transition metal chalcogels of approximate formula MoS3.4 achieve a high gravimetric capacity close to 600 mAh g–1 (close to 1000 mAh g–1 on a sulfur basis) as electrode materials for lithium-ion batteries. Transition metal chalcogels are amorphous and comprise polysulfide chains connected by inorganic linkers. The linkers appear to act as a “glue” in the electrode to prevent polysulfide shuttling. The Mo chalcogels function as electrodes in carbonate- and ether-based electrolytes, which further provides evidence of polysulfide solubility not beingmore » a limiting issue. We employ X-ray spectroscopy and operando pair distribution function techniques to elucidate the structural evolution of the electrode. Raman and X-ray photoelectron spectroscopy track the chemical moieties that arise during the anion-redox-driven processes. As a result, we find the redox state of Mo remains unchanged across the electrochemical cycling and, correspondingly, the redox is anion-driven.« less

  15. Novel shielding materials for space and air travel.

    PubMed

    Vana, N; Hajek, M; Berger, T; Fugger, M; Hofmann, P

    2006-01-01

    The reduction of dose onboard spacecraft and aircraft by appropriate shielding measures plays an essential role in the future development of space exploration and air travel. The design of novel shielding strategies and materials may involve hydrogenous composites, as it is well known that liquid hydrogen is most effective in attenuating charged particle radiation. As precursor for a later flight experiment, the shielding properties of newly developed hydrogen-rich polymers and rare earth-doped high-density rubber were tested in various ground-based neutron and heavy ion fields and compared with aluminium and polyethylene as reference materials. Absorbed dose, average linear energy transfer and gamma-equivalent neutron absorbed dose were determined by means of LiF:Mg,Ti thermoluminescence dosemeters and CR-39 plastic nuclear track detectors. First results for samples of equal aerial density indicate that selected hydrogen-rich plastics and rare-earth-doped rubber may be more effective in attenuating cosmic rays by up to 10% compared with conventional aluminium shielding. The appropriate adaptation of shielding thicknesses may thus allow reducing the biologically relevant dose. Owing to the lower density of the plastic composites, mass savings shall result in a significant reduction of launch costs. The experiment was flown as part of the European Space Agency's Biopan-5 mission in May 2005.

  16. Electrochemical and thermodynamic studies of the electrode materials for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Bang, Hyun Joo

    profiles observed during the charge and discharge processes are related to the Li insertion/extraction reaction in the spinel host structure for both materials. The reversible heat generation due to the lithium insertion/extraction reaction in the host electrode is estimated on the basis of the cell entropy change. The heat generation calculated from DeltaS and the open circuit potential results is consistent with the heat profile (exothermic/endothermic) generated during the charge/discharge process and with the magnitude of the heat generation from the experimental results obtained from the IMC at a slow charge/discharge rate. The irreversible heat generation dependence on the current rate is discussed at different discharge rates.

  17. Beneficial effects of air inclusions on the performance of ethylene vinyl acetate (EVA) mouthguard material

    PubMed Central

    Westerman, B; Stringfellow, P; Eccleston, J

    2002-01-01

    Objective: To investigate the impact characteristics of an ethylene vinyl acetate (EVA) mouthguard material with regulated air inclusions, which included various air cell volumes and wall thickness between air cells. In particular, the aim was to identify the magnitude and direction of forces within the impacts. Method: EVA mouthguard material, 4 mm thick and with and without air inclusions, was impacted with a constant force impact pendulum with an energy of 4.4 J and a velocity of 3 m/s. Transmitted forces through the EVA material were measured using an accelerometer, which also allowed the determination of force direction and magnitude within the impacts. Results: Statistically significant reductions in the transmitted forces were observed with all the air inclusion materials when compared with EVA without air inclusions. Maximum transmitted force through one air inclusion material was reduced by 32%. Force rebound was eliminated in one material, and reduced second force impulses were observed in all the air inclusion materials. Conclusion: The regulated air inclusions improved the impact characteristics of the EVA mouthguard material, the material most commonly used in mouthguards world wide. PMID:11867493

  18. Ion selective electrode for determination of chloride ion in biological materials, food products, soils and waste water.

    PubMed

    Sekerka, I; Lechner, J F

    1978-11-01

    The chloride ion selective electrode is used for a rapid, simple, and reliable determination of chloride ion in biological materials (blood serum, urine, fish, and plant tissues), food products (milk, beef extract, nutrient broth and orange, tomato, and grapefruit juices), soils, and waste water (industrial and municipal). The method consists of treating the samples with perchloric acid (pH 1) and potassium peroxydisulfate and determining the chloride content either by a calibration curve or by known addition or analyte addition, using the chloride ion selective electrode. Such sample treatment eliminates most of the interferences occurring in the samples, including iodide, complexing and reducing compounds, and macromolecular and surface-active species. The method is suitable for a wide range of chloride concentration, e.g., 5010 ppm Cl- in nutrient broth and 4890 ppm in beef extract and as low as 12 and 80 ppm in soil extracts.

  19. Nanostructured TiO2-coated activated carbon composite as an electrode material for asymmetric hybrid capacitors.

    PubMed

    Kim, Sang-Ok; Lee, Joong Kee

    2012-02-01

    A nanostructured TiO2-coated activated carbon (TAC) composite was synthesized by a modified sol-gel reaction and employed it as a negative electrode active material for an asymmetric hybrid capacitor. The structural characterization showed that the TiO2 nano-layer was deposited on the surface of the activated carbon and the TAC composite has a highly mesoporous structure. The evaluation of electrochemical characteristics of the TAC electrode was carried out by galvanostatic charge/discharge cycling tests and electrochemical impedance spectroscopy. The obtained specific capacitance of the TAC composite was 42.87 F/g, which showed by 27.1% higher than that of the activated carbon (AC). The TAC composite also exhibited an excellent cycle performance and kept 95% of initial capacitance over 500 cycles.

  20. Study of electrochemical properties of thin film materials obtained using plasma technologies for production of electrodes for pacemakers

    NASA Astrophysics Data System (ADS)

    Obrezkov, O. I.; Vinogradov, V. P.; Krauz, V. I.; Mozgrin, D. V.; Guseva, I. A.; Andreev, E. S.; Zverev, A. A.; Starostin, A. L.

    2016-09-01

    Studies of thin film materials (TFM) as coatings of tips of pacemaker electrodes implanted into the human heart have been performed. TFM coatings were deposited in vacuum by arc magnetron discharge plasma, by pulsed discharge of “Plasma Focus”, and by electron beam evaporation. Simulation of electric charge transfer to the heart in physiological blood- imitator solution and determination of electrochemical properties of the coatings were carried out. TFM of highly developed surface of contact with tissue was produced by argon plasma spraying of titanium powder with subsequent coating by titanium nitride in vacuum arc assisted by Ti ion implantation. The TFM coatings of pacemaker electrode have passed necessary clinical tests and were used in medical practice. They provide low voltage myocardium stimulation thresholds within the required operating time.

  1. Electrochemical Properties of Poly(Anthraquinonyl Sulfide)/Graphene Sheets Composites as Electrode Materials for Electrochemical Capacitors

    PubMed Central

    Lee, Wonkyun; Suzuki, Shinya; Miyayama, Masaru

    2014-01-01

    Poly(anthraquinonyl sulfide) (PAQS)/graphene sheets (GSs) composite was synthesized through in situ polymerization to evaluate its performance as an electrode material for electrochemical capacitors. PAQS was successfully synthesized in the presence of GSs with uniform distribution. PAQS/GSs showed a pair of reversible redox peaks at around 0 V (vs. Ag/AgCl). The specific capacitance of PAQS/GSs was 349 F·g−1 (86 mAh·g−1) at a current density of 500 mA·g−1, and a capacitance of 305 F·g−1 was maintained even at a high current density of 5000 mA·g−1. The in situ polymerization of PAQS with GSs facilitated their interaction and enabled faster charge transfer and redox reaction, resulting in enhanced electrode properties.

  2. Electrochemical Properties of Poly(Anthraquinonyl Sulfide)/Graphene Sheets Composites as Electrode Materials for Electrochemical Capacitors.

    PubMed

    Lee, Wonkyun; Suzuki, Shinya; Miyayama, Masaru

    2014-07-30

    Poly(anthraquinonyl sulfide) (PAQS)/graphene sheets (GSs) composite was synthesized through in situ polymerization to evaluate its performance as an electrode material for electrochemical capacitors. PAQS was successfully synthesized in the presence of GSs with uniform distribution. PAQS/GSs showed a pair of reversible redox peaks at around 0 V (vs. Ag/AgCl). The specific capacitance of PAQS/GSs was 349 F·g(-1) (86 mAh·g(-1)) at a current density of 500 mA·g(-1), and a capacitance of 305 F·g(-1) was maintained even at a high current density of 5000 mA·g(-1). The in situ polymerization of PAQS with GSs facilitated their interaction and enabled faster charge transfer and redox reaction, resulting in enhanced electrode properties.

  3. Nanostructured carbon materials based electrothermal air pump actuators

    NASA Astrophysics Data System (ADS)

    Liu, Qing; Liu, Luqi; Kuang, Jun; Dai, Zhaohe; Han, Jinhua; Zhang, Zhong

    2014-05-01

    Actuator materials can directly convert different types of energy into mechanical energy. In this work, we designed and fabricated electrothermal air pump-type actuators by utilization of various nanostructured carbon materials, including single wall carbon nanotubes (SWCNTs), reduced graphene oxide (r-GO), and graphene oxide (GO)/SWCNT hybrid films as heating elements to transfer electrical stimulus into thermal energy, and finally convert it into mechanical energy. Both the actuation displacement and working temperature of the actuator films show the monotonically increasing trend with increasing driving voltage within the actuation process. Compared with common polymer nanocomposites based electrothermal actuators, our actuators exhibited better actuation performances with a low driving voltage (<10 V), large generated stress (tens of MPa), high gravimetric density (tens of J kg-1), and short response time (few hundreds of milliseconds). Besides that, the pump actuators exhibited excellent stability under cyclic actuation tests. Among these actuators, a relatively larger actuation strain was obtained for the r-GO film actuator due to the intrinsic gas-impermeability nature of graphene platelets. In addition, the high modulus of the r-GO and GO/SWCNT films also guaranteed the large generated stress and high work density. Specifically, the generated stress and gravimetric work density of the GO/SWCNT hybrid film actuator could reach up to more than 50 MPa and 30 J kg-1, respectively, under a driving voltage of 10 V. The resulting stress value is at least two orders of magnitude higher than that of natural muscles (~0.4 MPa).Actuator materials can directly convert different types of energy into mechanical energy. In this work, we designed and fabricated electrothermal air pump-type actuators by utilization of various nanostructured carbon materials, including single wall carbon nanotubes (SWCNTs), reduced graphene oxide (r-GO), and graphene oxide (GO)/SWCNT hybrid

  4. Method of preparing a positive electrode for an electrochemical cell

    DOEpatents

    Tomczuk, Zygmunt

    1979-01-01

    A method of preparing an electrochemical cell including a metal sulfide as the positive electrode reactant and lithium alloy as the negative electrochemical reactant with an alkali metal, molten salt electrolyte is disclosed which permits the assembly to be accomplished in air. The electrode reactants are introduced in the most part as a sulfide of lithium and the positive electrode metal in a single-phase compound. For instance, Li.sub.2 FeS.sub.2 is a single-phase compound that is produced by the reaction of Li.sub.2 S and FeS. This compound is an intermediate in the positive electrode cycle from FeS.sub.2 to Fe and Li.sub.2 S. Its use minimizes volumetric changes from the assembled to the charged and discharged conditions of the electrode and minimizes electrode material interaction with air and moisture during assembly.

  5. Nanostructured carbon materials based electrothermal air pump actuators.

    PubMed

    Liu, Qing; Liu, Luqi; Kuang, Jun; Dai, Zhaohe; Han, Jinhua; Zhang, Zhong

    2014-06-21

    Actuator materials can directly convert different types of energy into mechanical energy. In this work, we designed and fabricated electrothermal air pump-type actuators by utilization of various nanostructured carbon materials, including single wall carbon nanotubes (SWCNTs), reduced graphene oxide (r-GO), and graphene oxide (GO)/SWCNT hybrid films as heating elements to transfer electrical stimulus into thermal energy, and finally convert it into mechanical energy. Both the actuation displacement and working temperature of the actuator films show the monotonically increasing trend with increasing driving voltage within the actuation process. Compared with common polymer nanocomposites based electrothermal actuators, our actuators exhibited better actuation performances with a low driving voltage (<10 V), large generated stress (tens of MPa), high gravimetric density (tens of J kg(-1)), and short response time (few hundreds of milliseconds). Besides that, the pump actuators exhibited excellent stability under cyclic actuation tests. Among these actuators, a relatively larger actuation strain was obtained for the r-GO film actuator due to the intrinsic gas-impermeability nature of graphene platelets. In addition, the high modulus of the r-GO and GO/SWCNT films also guaranteed the large generated stress and high work density. Specifically, the generated stress and gravimetric work density of the GO/SWCNT hybrid film actuator could reach up to more than 50 MPa and 30 J kg(-1), respectively, under a driving voltage of 10 V. The resulting stress value is at least two orders of magnitude higher than that of natural muscles (∼ 0.4 MPa).

  6. rGO/SWCNT composites as novel electrode materials for electrochemical biosensing.

    PubMed

    Huang, Tzu-Yen; Huang, Jen-Hsien; Wei, Hung-Yu; Ho, Kuo-Chuan; Chu, Chih-Wei

    2013-05-15

    In this study we performed electrochemical sensing using conductive carbon composite films containing reduced graphene oxide (rGO) and single-walled carbon nanotubes (SWCNTs) as electrode modifiers on glassy carbon electrodes (GCEs). Raman spectroscopy, transmission electron microscopy, atomic force microscopy, and scanning electron microscopy all suggested that the rGO acted as a surfactant, covering and smoothing out the surface, and that the SWCNTs acted as a conducting bridge to connect the isolated rGO sheets, thereby (i) minimizing the barrier for charge transfer between the rGO sheets and (ii) increasing the conductivity of the film. We used the rGO/SWCNT-modified GCE as a sensor to analyze hydrogen peroxide (H2O2) and β-nicotinamide adenine dinucleotide (NADH), obtaining substantial improvements in electrochemical reactivity and detection limits relative to those obtained from rGO- and SWCNT-modified electrodes, presumably because of the higher conductivity and greater coverage on the GCE, due to π-π interactions originating from the graphitic structures of the rGO and SWCNTs. The electrocatalysis response was measured by cyclic voltammetry and amperometric current-time (i-t) curve techniques. The linear concentration range of H2O2 and NADH detection at rGO/SWCNT-modified electrode is 0.5-5M and 20-400μM. The sensitivity for H2O2 and NADH detection is 2732.4 and 204μAmM(-1)cm(-2), and the limit of detection is 1.3 and 0.078μM respectively. Furthermore, interference tests indicated that the carbon composite film exhibited high selectivity toward H2O2 and NADH. Using GO as a solubilizing agent for SWCNTs establishes a new class of carbon electrodes for electrochemical sensors.

  7. A perovskite oxide with high conductivities in both air and reducing atmosphere for use as electrode for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Lan, Rong; Cowin, Peter I.; Sengodan, Sivaprakash; Tao, Shanwen

    2016-08-01

    Electrode materials which exhibit high conductivities in both oxidising and reducing atmospheres are in high demand for solid oxide fuel cells (SOFCs) and solid oxide electrolytic cells (SOECs). In this paper, we investigated Cu-doped SrFe0.9Nb0.1O3‑δ finding that the primitive perovskite oxide SrFe0.8Cu0.1Nb0.1O3‑δ (SFCN) exhibits a conductivity of 63 Scm‑1and 60 Scm‑1 at 415 °C in air and 5%H2/Ar respectively. It is believed that the high conductivity in 5%H2/Ar is related to the exsolved Fe (or FeCu alloy) on exposure to a reducing atmosphere. To the best of our knowledge, the conductivity of SrFe0.8Cu0.1Nb0.1O3‑δ in a reducing atmosphere is the highest of all reported oxides which also exhibit a high conductivity in air. Fuel cell performance using SrFe0.8Cu0.1Nb0.1O3‑δ as the anode, (Y2O3)0.08(ZrO2)0.92 as the electrolyte and La0.8Sr0.2FeO3‑δ as the cathode achieved a power density of 423 mWcm‑2 at 700 °C indicating that SFCN is a promising anode for SOFCs.

  8. A perovskite oxide with high conductivities in both air and reducing atmosphere for use as electrode for solid oxide fuel cells

    PubMed Central

    Lan, Rong; Cowin, Peter I.; Sengodan, Sivaprakash; Tao, Shanwen

    2016-01-01

    Electrode materials which exhibit high conductivities in both oxidising and reducing atmospheres are in high demand for solid oxide fuel cells (SOFCs) and solid oxide electrolytic cells (SOECs). In this paper, we investigated Cu-doped SrFe0.9Nb0.1O3−δ finding that the primitive perovskite oxide SrFe0.8Cu0.1Nb0.1O3−δ (SFCN) exhibits a conductivity of 63 Scm−1and 60 Scm−1 at 415 °C in air and 5%H2/Ar respectively. It is believed that the high conductivity in 5%H2/Ar is related to the exsolved Fe (or FeCu alloy) on exposure to a reducing atmosphere. To the best of our knowledge, the conductivity of SrFe0.8Cu0.1Nb0.1O3−δ in a reducing atmosphere is the highest of all reported oxides which also exhibit a high conductivity in air. Fuel cell performance using SrFe0.8Cu0.1Nb0.1O3−δ as the anode, (Y2O3)0.08(ZrO2)0.92 as the electrolyte and La0.8Sr0.2FeO3−δ as the cathode achieved a power density of 423 mWcm−2 at 700 °C indicating that SFCN is a promising anode for SOFCs. PMID:27545200

  9. Applying a tapered electrode on a porous ceramic support tube by masking a band inside the tube and drawing in electrode material from the outside of the tube by suction

    DOEpatents

    Vasilow, Theodore R.; Zymboly, Gregory E.

    1991-01-01

    An electrode is deposited on a support by providing a porous ceramic support tube (10) having an open end (14) and closed end (16); masking at least one circumferential interior band (18 and 18') inside the tube; evacuating air from the tube by an evacuation system (30), to provide a permeability gradient between the masked part (18 and 18') and unmasked part (20) of the tube; applying a liquid dispersion of solid electrode particles to the outside surface of the support tube, where liquid flows through the wall, forming a uniform coating (42) over the unmasked support part (20) and a tapered coating over the masked part (18 and 18').

  10. Applying a tapered electrode on a porous ceramic support tube by masking a band inside the tube and drawing in electrode material from the outside of the tube by suction

    DOEpatents

    Vasilow, T.R.; Zymboly, G.E.

    1991-12-17

    An electrode is deposited on a support by providing a porous ceramic support tube having an open end and closed end; masking at least one circumferential interior band inside the tube; evacuating air from the tube by an evacuation system, to provide a permeability gradient between the masked part and unmasked part of the tube; applying a liquid dispersion of solid electrode particles to the outside surface of the support tube, where liquid flows through the wall, forming a uniform coating over the unmasked support part and a tapered coating over the masked part. 2 figures.

  11. Bacterial-cellulose-derived carbon nanofiber@MnO₂ and nitrogen-doped carbon nanofiber electrode materials: an asymmetric supercapacitor with high energy and power density.

    PubMed

    Chen, Li-Feng; Huang, Zhi-Hong; Liang, Hai-Wei; Guan, Qing-Fang; Yu, Shu-Hong

    2013-09-14

    A new kind of high-performance asymmetric supercapacitor is designed with pyrolyzed bacterial cellulose (p-BC)-coated MnO₂ as a positive electrode material and nitrogen-doped p-BC as a negative electrode material via an easy, efficient, large-scale, and green fabrication approach. The optimal asymmetric device possesses an excellent supercapacitive behavior with quite high energy and power density.

  12. Laser processing of SnO2 electrode materials for manufacturing of 3D micro-batteries

    NASA Astrophysics Data System (ADS)

    Kohler, R.; Proell, J.; Ulrich, S.; Przybylski, M.; Pfleging, W.

    2011-03-01

    The material development for advanced lithium-ion batteries plays an important role in future mobile applications and energy storage systems. It is assumed that electrode materials made of nano-composited materials will improve battery lifetime and will lead to an enhancement of lithium diffusion and thus improve battery capacity and cyclability. A major problem concerning thin film electrodes is, that increasing film thickness leads to an increase in lithium diffusion path lengths and thereby a decrease in power density. To overcome this problem, the investigation of a 3D-battery system with an increased surface area is necessary. UV-laser micromachining was applied to create defined line or grating structures via mask imaging. SnO2 is a highly investigated anode material for lithium-ion batteries. Yet, the enormous volume changes occurring during electrochemical cycling lead to immense loss of capacity. The formation of micropatterns via laser ablation to create structures which enable the compensation of the volume expansion was investigated in detail. Thin films of SnO2 were deposited in Ar:O2 atmosphere via r.f. magnetron sputtering on silicon and stainless steel substrates. The thin films were studied with X-ray diffraction to determine their crystallinity. The electrochemical properties of the manufactured films were investigated via electrochemical cycling against a lithium anode.

  13. Low resistance fuel electrodes

    DOEpatents

    Maskalick, Nichols J.; Folser, George R.

    1989-01-01

    An electrode 6 bonded to a solid, ion conducting electrolyte 5 is made, where the electrode 6 comprises a ceramic metal oxide 18, metal particles 17, and heat stable metal fibers 19, where the metal fibers provide a matrix structure for the electrode. The electrolyte 5 can be bonded to an air electrode cathode 4, to provide an electrochemical cell 2, preferably of tubular design.

  14. Scrubbing of contaminants from contaminated air streams with aerogel materials with optional photocatalytic destruction

    DOEpatents

    Attia, Yosry A.

    2000-01-01

    Disclosed is a method for separating a vaporous or gaseous contaminant from an air stream contaminated therewith. This method includes the steps of: (a) passing said contaminated air into a contact zone in which is disposed an aerogel material capable of selecting adsorbing said contaminant from air and therein contacting said contaminated air with an aerogel material; and (b) withdrawing from said zone, air depleted of said contaminant. For present purposes, "contaminant" means a material not naturally occurring in ambient air and/or a material naturally occurring in air but present at a concentration above that found in ambient air. Thus, the present invention scrubs (or treats) air for the purpose of returning it to its ambient composition. Also disclosed herein is a process for the photocatalytic destruction of contaminants from an air stream wherein the contaminated air stream is passed into a control cell or contact zone in which is disposed a photocatalytic aerogel and exposing said aerogel to ultraviolet (UV) radiation for photocatalytically destroying the adsorbed contaminant, and withdrawing from said cell an exhaust air stream depleted in said contaminant.

  15. Li-Rich Li-Si Alloy As A Lithium-Containing Negative Electrode Material Towards High Energy Lithium-Ion Batteries

    PubMed Central

    Iwamura, Shinichiroh; Nishihara, Hirotomo; Ono, Yoshitaka; Morito, Haruhiko; Yamane, Hisanori; Nara, Hiroki; Osaka, Tetsuya; Kyotani, Takashi

    2015-01-01

    Lithium-ion batteries (LIBs) are generally constructed by lithium-including positive electrode materials, such as LiCoO2, and lithium-free negative electrode materials, such as graphite. Recently, lithium-free positive electrode materials, such as sulfur, are gathering great attention from their very high capacities, thereby significantly increasing the energy density of LIBs. Though the lithium-free materials need to be combined with lithium-containing negative electrode materials, the latter has not been well developed yet. In this work, the feasibility of Li-rich Li-Si alloy is examined as a lithium-containing negative electrode material. Li-rich Li-Si alloy is prepared by the melt-solidification of Li and Si metals with the composition of Li21Si5. By repeating delithiation/lithiation cycles, Li-Si particles turn into porous structure, whereas the original particle size remains unchanged. Since Li-Si is free from severe constriction/expansion upon delithiation/lithiation, it shows much better cyclability than Si. The feasibility of the Li-Si alloy is further examined by constructing a full-cell together with a lithium-free positive electrode. Though Li-Si alloy is too active to be mixed with binder polymers, the coating with carbon-black powder by physical mixing is found to prevent the undesirable reactions of Li-Si alloy with binder polymers, and thus enables the construction of a more practical electrochemical cell. PMID:25626879

  16. Li-rich Li-Si alloy as a lithium-containing negative electrode material towards high energy lithium-ion batteries.

    PubMed

    Iwamura, Shinichiroh; Nishihara, Hirotomo; Ono, Yoshitaka; Morito, Haruhiko; Yamane, Hisanori; Nara, Hiroki; Osaka, Tetsuya; Kyotani, Takashi

    2015-01-28

    Lithium-ion batteries (LIBs) are generally constructed by lithium-including positive electrode materials, such as LiCoO2, and lithium-free negative electrode materials, such as graphite. Recently, lithium-free positive electrode materials, such as sulfur, are gathering great attention from their very high capacities, thereby significantly increasing the energy density of LIBs. Though the lithium-free materials need to be combined with lithium-containing negative electrode materials, the latter has not been well developed yet. In this work, the feasibility of Li-rich Li-Si alloy is examined as a lithium-containing negative electrode material. Li-rich Li-Si alloy is prepared by the melt-solidification of Li and Si metals with the composition of Li21Si5. By repeating delithiation/lithiation cycles, Li-Si particles turn into porous structure, whereas the original particle size remains unchanged. Since Li-Si is free from severe constriction/expansion upon delithiation/lithiation, it shows much better cyclability than Si. The feasibility of the Li-Si alloy is further examined by constructing a full-cell together with a lithium-free positive electrode. Though Li-Si alloy is too active to be mixed with binder polymers, the coating with carbon-black powder by physical mixing is found to prevent the undesirable reactions of Li-Si alloy with binder polymers, and thus enables the construction of a more practical electrochemical cell.

  17. Electrode polarization vs. Maxwell-Wagner-Sillars interfacial polarization in dielectric spectra of materials: Characteristic frequencies and scaling laws.

    PubMed

    Samet, M; Levchenko, V; Boiteux, G; Seytre, G; Kallel, A; Serghei, A

    2015-05-21

    The characteristic frequencies of electrode polarization and of interfacial polarization effects in dielectric spectra of ionic liquids and of polymer bi-layers are determined and systematically analyzed, based on dielectric measurements by means of broadband dielectric spectroscopy, numerical simulations, and analytical calculations. It is shown that, to a large extent, identical scaling laws can be derived for these two dielectric phenomena taking place at external and internal interfaces. Surprisingly, a fundamentally different behavior concerning the interrelation between the characteristic frequencies is found. This brings direct evidence that different manifestations of the phenomenon of electrical polarization can be discriminated by examining the inter-relation governing their characteristic frequencies, which can be of significant importance in disseminating the nature of different contributions appearing in the dielectric spectra of complex materials. Based on our analysis, we derive a new formula, valid for both electrode polarization and interfacial polarization effects, that allows one to determine the conductivity value from the frequency position of the Maxwell-Wagner-Sillars peak. An excellent agreement between experiment and calculations is obtained. The formula can be used, furthermore, to estimate the thickness of the interfacial layers formed due to electrode polarization effects. Values in the order of several nanometers, increasing with decreasing temperature, are reported.

  18. Overoxidized polypyrrole/graphene nanocomposite with good electrochemical performance as novel electrode material for the detection of adenine and guanine.

    PubMed

    Gao, Yan-Sha; Xu, Jing-Kun; Lu, Li-Min; Wu, Li-Ping; Zhang, Kai-Xin; Nie, Tao; Zhu, Xiao-Fei; Wu, Yao

    2014-12-15

    Most conducting polymer/graphene composites have excellent electrical conductivity. However, the background currents of these composites modified electrodes are much larger. In order to improve the sensitivities of these methods, it is necessary to decrease the background signal. In this paper, porous structure films of overoxidized polypyrrole/graphene (PPyox/GR) have been electrochemically coated onto glassy carbon electrode (GCE) and successfully utilized as an efficient electrode material for the quantitive detection of adenine and guanine, two of the most important components of DNA and RNA. The permselective polymer coatings with low background current could improve the selectivity and sensitivity of microelectrodes for the electropositive purine bases. The GRs into these polymers would further improve sensitivity by increasing the electroactive surface area. The electrochemical sensor can be applied to the quantification of adenine and guanine with a linear range covering 0.06-100 µM and 0.04-100 µM, and a low detection limit of 0.02 μM and 0.01 μM, respectively. More importantly, the proposed method was applied to quantify adenine and guanine in calf thymus DNA with satisfactory results.

  19. Electrodes made with disordered active material and methods of making the same

    SciTech Connect

    Keem, J.E.; Bergeron, R.C.; Custer, R.C.; McCallum, R.W.

    1987-01-20

    This patent describes a hydrogen storage electrode for an alkaline hydrogen storage electrochemical cell comprising at least one solid, metallic, amorphous electrochemically active body, capable of being self-supporting and formed by rapid solidification from a melt thereby having a non-particulate, dimensionally anisotropic shape characterized by a continuous amorphous structure throughout. The body has a composition comprising at least three elements, the three elements comprising titanium, nickel and at least one element selected from the group consisting of aluminum, boron, chromium, cobalt, hafnium, indium, lead, magnesium, molybdenum, niobium, palladium, tin, zirconium and rare earth metals. Each of the elements is preset in an effective amount so that the electrode is capable of being electrochemically charged with hydrogen to store energy and capable of electrochemically discharging hydrogen and releasing energy, while maintaining its structural integrity during electrochemical charge and discharge cycles.

  20. Interconnecting Carbon Fibers with the In-situ Electrochemically Exfoliated Graphene as Advanced Binder-free Electrode Materials for Flexible Supercapacitor.

    PubMed

    Zou, Yuqin; Wang, Shuangyin

    2015-07-07

    Flexible energy storage devices are highly demanded for various applications. Carbon cloth (CC) woven by carbon fibers (CFs) is typically used as electrode or current collector for flexible devices. The low surface area of CC and the presence of big gaps (ca. micro-size) between individual CFs lead to poor performance. Herein, we interconnect individual CFs through the in-situ exfoliated graphene with high surface area by the electrochemical intercalation method. The interconnected CFs are used as both current collector and electrode materials for flexible supercapacitors, in which the in-situ exfoliated graphene act as active materials and conductive "binders". The in-situ electrochemical intercalation technique ensures the low contact resistance between electrode (graphene) and current collector (carbon cloth) with enhanced conductivity. The as-prepared electrode materials show significantly improved performance for flexible supercapacitors.

  1. Method and apparatus for preventing air pollution by the entrainment of particulate material

    SciTech Connect

    Walters, W.Z.

    1986-05-06

    A particulate material handling system is described which is capable of reducing the pollution of air by the entrainment of particulate solids. The system consists of: a covered elevated conveyor means from which the particulate material can be deposited to form a pile of that material in a designated area or to add to such a pile and air diversion means which is adapted to so cooperate with the conveyor as to prevent wind from entraining fines in the particulate material as it is dumped onto the pile or into the area and to prevent wind from stripping and entraining material from the pile by diverting the wind upwardly over the top of the elevated conveyor means and creating an eddy in the air on the leeward side of the pile of particulate material. Particulate material entrained in the air diverted over the elevated conveyor means will drop out of the air currents in the region where the eddy currents are formed and be deposited on the leeward side of the pile, the air diversion means being vertically oriented and adapted to extend lengthwise along at least the initial segment of the pile and essentially along the longitudinal centerline. The air diversion means have a lower edge which is adapted to be proximate to, in contact with, or buried in the pile depending on the height of the pile, and the conveyor being so constructed that it is capable of depositing particulate material on both sides of the air diversion means.

  2. Carbonaceous materials and their advances as a counter electrode in dye-sensitized solar cells: challenges and prospects.

    PubMed

    Kouhnavard, Mojgan; Ludin, Norasikin Ahmad; Ghaffari, Babak V; Sopian, Kamarozzaman; Ikeda, Shoichiro

    2015-05-11

    Dye-sensitized solar cells (DSSCs) serve as low-costing alternatives to silicon solar cells because of their low material and fabrication costs. Usually, they utilize Pt as the counter electrode (CE) to catalyze the iodine redox couple and to complete the electric circuit. Given that Pt is a rare and expensive metal, various carbon materials have been intensively investigated because of their low costs, high surface areas, excellent electrochemical stabilities, reasonable electrochemical activities, and high corrosion resistances. In this feature article, we provide an overview of recent studies on the electrochemical properties and photovoltaic performances of carbon-based CEs (e.g., activated carbon, nanosized carbon, carbon black, graphene, graphite, carbon nanotubes, and composite carbon). We focus on scientific challenges associated with each material and highlight recent advances achieved in overcoming these obstacles. Finally, we discuss possible future directions for this field of research aimed at obtaining highly efficient DSSCs.

  3. Conductive Polymer Binder for High-Tap-Density Nanosilicon Material for Lithium-Ion Battery Negative Electrode Application.

    PubMed

    Zhao, Hui; Wei, Yang; Qiao, Ruimin; Zhu, Chenhui; Zheng, Ziyan; Ling, Min; Jia, Zhe; Bai, Ying; Fu, Yanbao; Lei, Jinglei; Song, Xiangyun; Battaglia, Vincent S; Yang, Wanli; Messersmith, Phillip B; Liu, Gao

    2015-12-09

    High-tap-density silicon nanomaterials are highly desirable as anodes for lithium ion batteries, due to their small surface area and minimum first-cycle loss. However, this material poses formidable challenges to polymeric binder design. Binders adhere on to the small surface area to sustain the drastic volume changes during cycling; also the low porosities and small pore size resulting from this material are detrimental to lithium ion transport. This study introduces a new binder, poly(1-pyrenemethyl methacrylate-co-methacrylic acid) (PPyMAA), for a high-tap-density nanosilicon electrode cycled in a stable manner with a first cycle efficiency of 82%-a value that is further improved to 87% when combined with graphite material. Incorporating the MAA acid functionalities does not change the lowest unoccupied molecular orbital (LUMO) features or lower the adhesion performance of the PPy homopolymer. Our single-molecule force microscopy measurement of PPyMAA reveals similar adhesion strength between polymer binder and anode surface when compared with conventional polymer such as homopolyacrylic acid (PAA), while being electronically conductive. The combined conductivity and adhesion afforded by the MAA and pyrene copolymer results in good cycling performance for the high-tap-density Si electrode.

  4. Effect of electrode material on characteristics of non-volatile resistive memory consisting of Ag2S nanoparticles

    NASA Astrophysics Data System (ADS)

    Jang, Jaewon

    2016-07-01

    In this study, Ag2S nanoparticles are synthesized and used as the active material for two-terminal resistance switching memory devices. Sintered Ag2S films are successfully crystallized on plastic substrates with synthesized Ag2S nanoparticles, after a relatively low-temperature sintering process (200 °C). After the sintering process, the crystallite size is increased from 6.8 nm to 80.3 nm. The high ratio of surface atoms to inner atoms of nanoparticles reduces the melting point temperature, deciding the sintering process temperature. In order to investigate the resistance switching characteristics, metal/Ag2S/metal structures are fabricated and tested. The effect of the electrode material on the non-volatile resistive memory characteristics is studied. The bottom electrochemically inert materials, such as Au and Pt, were critical for maintaining stable memory characteristics. By using Au and Pt inert bottom electrodes, we are able to significantly improve the memory endurance and retention to more than 103 cycles and 104 sec, respectively.

  5. Novel GO-LaSmO2 Nanocomposite as an Effective Electrode Material for Hydrogen Fuel Cells

    NASA Astrophysics Data System (ADS)

    El-Amin, Ayman A.; Othman, Abdelhameed M.

    2016-04-01

    Nano-composites of lanthanum-samarium oxide (LaSmO2) were prepared in the absence and presence of graphene oxide (GO) and characterized as an effective electrode material for hydrogen fuel cells. X-ray and scanning electron microscope investigations revealed grain sizes of 8 nm for LaSmO2 and 12 nm for GO-LaSmO2 composites. The x-ray diffraction pattern showed sharp peaks, indicating a well-crystallized phase indexable to a rhombohedral structure with space group R 3 C , and their structural refinement performed in the hexagonal mode. The ionic conductivity of LaSmO2 was found to be 4.12 × 10-5 S/cm, while in the presence of GO it was enhanced to 5.32 × 10-5 S/cm. The mechanism of conduction in the proposed nano-materials was investigated based on frequency exponent S. The values of S were observed to decrease with increasing temperature. This result was found to be in good agreement with the correlated barrier hopping (CBH) model. The present work revealed GO to be a conductivity enhancer that caused the GO-LaSmO2 composite to be an effective electrode material for hydrogen fuel cells.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  7. The preparation of copper fine particle paste and its application as the inner electrode material of a multilayered ceramic capacitor

    NASA Astrophysics Data System (ADS)

    Yonezawa, Tetsu; Takeoka, Shinsuke; Kishi, Hiroshi; Ida, Kiyonobu; Tomonari, Masanori

    2008-04-01

    Well size-controlled copper fine particles (diameter: 100-300 nm) were used as the inner electrode material of multilayered ceramic capacitors (MLCCs). The particles were dispersed in terpineol to form a printing paste with 50 wt% copper particles. The MLCC precursor modules prepared by the layer-by-layer printing of copper and BaTiO3 particles were cosintered. Detailed observation of the particles, paste, and MLCCs before and after sintering was carried out by electron microscopy. The sintering temperature of Cu-MLCC was as low as 960 °C. The permittivity of these MLCCs was successfully measured with the copper inner layers.

  8. Manufacturing of Protected Lithium Electrodes for Advanced Lithium-Air, Lithium-Water & Lithium-Sulfur Batteries

    SciTech Connect

    Visco, Steven J

    2015-11-30

    The global demand for rechargeable batteries is large and growing rapidly. Assuming the adoption of electric vehicles continues to increase, the need for smaller, lighter, and less expensive batteries will become even more pressing. In this vein, PolyPlus Battery Company has developed ultra-light high performance batteries based on its proprietary protected lithium electrode (PLE) technology. The Company’s Lithium-Air and Lithium-Seawater batteries have already demonstrated world record performance (verified by third party testing), and we are developing advanced lithium-sulfur batteries which have the potential deliver high performance at low cost. In this program PolyPlus Battery Company teamed with Corning Incorporated to transition the PLE technology from bench top fabrication using manual tooling to a pre- commercial semi-automated pilot line. At the inception of this program PolyPlus worked with a Tier 1 battery manufacturing engineering firm to design and build the first-of-its-kind pilot line for PLE production. The pilot line was shipped and installed in Berkeley, California several months after the start of the program. PolyPlus spent the next two years working with and optimizing the pilot line and now produces all of its PLEs on this line. The optimization process successfully increased the yield, throughput, and quality of PLEs produced on the pilot line. The Corning team focused on fabrication and scale-up of the ceramic membranes that are key to the PLE technology. PolyPlus next demonstrated that it could take Corning membranes through the pilot line process to produce state-of-the-art protected lithium electrodes. In the latter part of the program the Corning team developed alternative membranes targeted for the large rechargeable battery market. PolyPlus is now in discussions with several potential customers for its advanced PLE-enabled batteries, and is building relationships and infrastructure for the transition into manufacturing. It is likely

  9. New electrosurgical ball electrode with nonstick properties

    NASA Astrophysics Data System (ADS)

    Rondinone, Joseph; Brassell, James; Miller, Scott A., III; Thorne, Jonathan O.; Rondinone, David M.; Safabash, Jason; Vega, Felix

    1998-04-01

    A new electrosurgical ball electrode (SilverBulletTM) has been developed for applying radiofrequency (RF) energy to fuse biological and other materials to tissue surfaces. Specifically, the electrode was developed for use in conjunction with the Fusion Medical Technologies, Inc. gelatin patch (RapiSealTM) for use in pulmonary surgery to seal air leaks, and in solid abdominal organ surgeries to provide hemostatic tamponade. The new electrode allows for the application of RF energy in contact mode without the problems of the electrode sticking to the gelatin patch or the underlying tissue. Designed for use with commercially available electrosurgical handpieces, the electrode consists of a stainless steel connector that fits into the hand- piece, and an electrode assembly made from silver that includes a shank region, and a tip extension extending distally from the shank region. The distal tip of the tip extension is rounded and has a length of about 10 mm. The uniqueness of this electrode is the shank region which has a cross sectional area that is larger than the tip extension. The shank region acts as a heat sink to draw away heat from the tip extension while the tip extension itself remains sufficiently small to access desired target sites and display the desired energy transfer properties. In addition to the physical design, the use of silver as the core element provides a material with high electrical and thermal conductivities. The bulk of the electrode is appropriately insulated.

  10. Controlled porosity in electrodes

    DOEpatents

    Chiang, Yet-Ming; Bae, Chang-Jun; Halloran, John William; Fu, Qiang; Tomsia, Antoni P.; Erdonmez, Can K.

    2015-06-23

    Porous electrodes in which the porosity has a low tortuosity are generally provided. In some embodiments, the porous electrodes can be designed to be filled with electrolyte and used in batteries, and can include low tortuosity in the primary direction of ion transport during charge and discharge of the battery. In some embodiments, the electrodes can have a high volume fraction of electrode active material (i.e., low porosity). The attributes outlined above can allow the electrodes to be fabricated with a higher energy density, higher capacity per unit area of electrode (mAh/cm.sup.2), and greater thickness than comparable electrodes while still providing high utilization of the active material in the battery during use. Accordingly, the electrodes can be used to produce batteries with high energy densities, high power, or both compared to batteries using electrodes of conventional design with relatively highly tortuous pores.

  11. Air emissions from exposed contaminated sediments and dredged material

    SciTech Connect

    Valsaraj, K.T.; Ravikrishna, R.; Reible, D.D.; Thibodeaux, L.J.; Choy, B.; Price, C.B.; Brannon, J.M.; Myers, T.E.; Yost, S.

    1999-01-01

    The sediment-to-air fluxes of two polycyclic aromatic hydrocarbons (phenanthrene and pyrene) and a heterocyclic aromatic hydrocarbon (dibenzofuran) from a laboratory-contaminated sediment and those of three polycyclic aromatic hydrocarbons (naphthalene, phenanthrene, and pyrene) from three field sediments were investigated in experimental microcosms. The flux was dependent on the sediment moisture content, air-filled porosity, and the relative humidity of the air flowing over the sediment surface. The mathematical model predictions of flux from the laboratory-spiked sediment agreed with observed values. The fluxes of compounds with higher hydrophobicity were more air-side resistance controlled. Conspicuous differences were observed between the fluxes from the laboratory-spiked and two of the three field sediments. Two field sediments showed dramatic increases in mass-transfer resistances with increasing exposure time and had significant fractions of oil and grease. The proposed mathematical model was inadequate for predicting the flux from the latter field sediments. Sediment reworking enhanced the fluxes from the field sediments due to exposure of fresh solids to the air. Variations in flux from the lab-spiked sediment as a result of change in air relative humidity were due to differences in retardation of chemicals on a dry or wet surface sediment. High moisture in the air over the dry sediment increased the competition for sorption sites between water and contaminant and increased the contaminant flux.

  12. Thin Film Electrode Materials Li4Ti5O12 and LiCoO2 Prepared by Spray Pyrolysis Method

    NASA Astrophysics Data System (ADS)

    Takahashi, M.; Tani, J.; Kido, H.; Hayashi, A.; Tadanaga, K.; Tatsumisago, M.

    2011-05-01

    The Li4Ti5O12 and the LiCoO2 have been considered as promising candidates of electrode materials for all-solid-state lithium secondary batteries. The spray pyrolysis method is a useful economical technique to prepare various thicknesses of oxide films though have not been intensively studied for fabrication of thin film lithium batteries. Thin films of Li4Ti5O12 and LiCoO2 electrode materials about 100-400 nm were prepared on quartz and gold substrates by the spray pyrolysis method by using Liacac and, TiO(acac)4 or Co(acac)3 with DMF solvent as starting materials. Electric properties as electrode materials for lithium batteries were estimated by using 3 probe liquid cells with liquid electrolyte LiPF6 in EC-DMC and Li metal as reference and counter electrodes. Structure and morphology of the films were investigated by XRD and SEM. Crystalline Li4Ti5O12 and LiCoO2 thin films were found to be prepared over 700 °C of substrate temperature. Cyclic voltammograms of the Li4Ti5O12 electrode thin films showed sharp oxidation and reduction peaks around 1.6 and 1.5 V, respectively. Charge-discharge curves for both Li4Ti5O12 and LiCoO2 electrode thin films showed discharge plateaus around 1.4 and 3.8 V with about 80 mAhg-1 of capacity. These results showed that these electrode thin films prepared by the spray pyrolysis method are electrochemically active and spray pyrolysis method is a promising technique to prepare thin film electrode materials.

  13. Synthesis of a novel electrode material containing phytic acid-polyaniline nanofibers for simultaneous determination of cadmium and lead ions.

    PubMed

    Huang, Hui; Zhu, Wencai; Gao, Xiaochun; Liu, Xiuyu; Ma, Houyi

    2016-12-01

    The development of nanostructured conducting polymers based materials for electrochemical applications has attracted intense attention due to their environmental stability, unique reversible redox properties, abundant electron active sites, rapid electron transfer and tunable conductivity. Here, a phytic acid doped polyaniline nanofibers based nanocomposite was synthesized using a simple and green method, the properties of the resulting nanomaterial was characterized by electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). A glassy carbon electrode modified by the nanocomposite was evaluated as a new platform for the simultaneous detection of trace amounts of Cd(2+) and Pb(2+) using differential pulse anodic stripping voltammetry (DPASV). The synergistic contribution from PANI nanofibers and phytic acid enhances the accumulation efficiency and the charge transfer rate of metal ions during the DPASV analysis. Under the optimal conditions, good linear relationships were obtained for Cd(2+) in a range of 0.05-60 μg L(-1), with the detection limit (S/N = 3) of 0.02 μg L(-1), and for Pb(2+) in a range of 0.1-60 μg L(-1), with the detection limit (S/N = 3) of 0.05 μg L(-1). The new electrode was successfully applied to real water samples for simultaneous detection of Cd(2+) and Pb(2+) with good recovery rates. Therefore, the new electrode material may be a capable candidate for the detection of trace levels of heavy metal ions.

  14. Amorphous thin film ruthenium oxide as an electrode material for electrochemical capacitors

    SciTech Connect

    Jow, T.R.; Zheng, J.P.

    1995-12-31

    Ruthenium oxide thin films of an amorphous phase were successfully prepared on a titanium (Ti) substrate at temperatures below 160 C. The sol-gel process using metal alkoxide precursor in nonaqueous solvents was used to prepare these films. The preliminary results showed that a specific capacitance of 430 F/g can be achieved for amorphous ruthenium oxide electrode in sulfuric acid. Films prepared by this method are compared with the films prepared by the thermal decomposition of the aqueous ruthenium chloride solution at temperatures above 300 C. The specific capacitance, the crystalline structure, and the surface morphology of these films as a function of the preparation temperature were also discussed.

  15. Production of an ion-exchange membrane-catalytic electrode bonded material for electrolytic cells

    NASA Technical Reports Server (NTRS)

    Takenaka, H.; Torikai, E.

    1986-01-01

    A good bond is achieved by placing a metal salt in solution on one side of a membrane and a reducing agent on the other side so that the reducing agent penetrates the membrane and reduces the metal. Thus, a solution containing Pt, Rh, etc., is placed on one side of the membrane and a reducing agent such as NaBH, is placed on the other side. The bonded metal layer obtained is superior in catalytic activity and is suitable as an electrode in a cell such as for solid polymer electrolyte water electrolysis.

  16. Laser printing and femtosecond laser structuring of electrode materials for the manufacturing of 3D lithium-ion micro-batteries

    NASA Astrophysics Data System (ADS)

    Smyrek, P.; Kim, H.; Zheng, Y.; Seifert, H. J.; Piqué, A.; Pfleging, W.

    2016-04-01

    Recently, three-dimensional (3D) electrode architectures have attracted great interest for the development of lithium-ion micro-batteries applicable for Micro-Electro-Mechanical Systems (MEMS), sensors, and hearing aids. Since commercial available micro-batteries are mainly limited in overall cell capacity by their electrode footprint, new processing strategies for increasing both capacity and electrochemical performance have to be developed. In case of such standard microbatteries, two-dimensional (2D) electrode arrangements are applied with thicknesses up to 200 μm. These electrode layers are composed of active material, conductive agent, graphite, and polymeric binder. Nevertheless, with respect to the type of active material, the active material to conductive agent ratio, and the film thickness, such thick-films suffer from low ionic and electronic conductivities, poor electrolyte accessibility, and finally, limited electrochemical performance under challenging conditions. In order to overcome these drawbacks, 3D electrode arrangements are under intense investigation since they allow the reduction of lithium-ion diffusion pathways in between inter-digitated electrodes, even for electrodes with enhanced mass loadings. In this paper, we present how to combine laser-printing and femtosecond laser-structuring for the development of advanced 3D electrodes composed of Li(Ni1/3Mn1/3Co1/3)O2 (NMC). In a first step, NMC thick-films were laser-printed and calendered to achieve film thicknesses in the range of 50 μm - 80 μm. In a second step, femtosecond laser-structuring was carried out in order to generate 3D architectures directly into thick-films. Finally, electrochemical cycling of laser-processed films was performed in order to evaluate the most promising 3D electrode designs suitable for application in long life-time 3D micro-batteries.

  17. Graphene-like carbon nanosheets as a new electrode material for electrochemical determination of hydroquinone and catechol.

    PubMed

    Jiang, Hongmei; Wang, Shuqin; Deng, Wenfang; Zhang, Youming; Tan, Yueming; Xie, Qingji; Ma, Ming

    2017-03-01

    We report here graphene-like carbon nanosheets (GCN) as a new electrode material for the electrochemical determination of hydroquinone (HQ) and catechol (CC). The GCN were prepared from maltose using ammonia chloride as a blowing agent and cobalt nitrate as a graphitization catalyst precursor. The as-prepared GCN material shows high graphitization degree, abundant porosity, and large specific surface area. Two well-separated anodic peaks for HQ and CC are obtained at GCN modified glassy carbon electrode (GCE) with a peak-to-peak separation of 118mV. The redox peak currents of HQ and CC at GCN/GCE were much higher than those at bare GCE and reduced graphene oxide modified GCE. For differential pulse voltammetric detection of HQ and CC, the GCN/GCE shows linear response ranges of 1×10(-7) ̶ 3×10(-5)M for HQ and 5×10(-7) ̶ 5×10(-5)M for CC, with detection limits of 2×10(-8)M for HQ, and 5×10(-8) M for CC. Satisfactory recoveries were achieved for the determination of HQ and CC in real water samples.

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

    PubMed

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

    2015-02-04

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

  19. An uniform DBD plasma excited by bipolar nanosecond pulse using wire-cylinder electrode configuration in atmospheric air.

    PubMed

    Jiang, Peng-Chao; Wang, Wen-Chun; Zhang, Shuai; Jia, Li; Yang, De-Zheng; Tang, Kai; Liu, Zhi-Jie

    2014-03-25

    In this study, a bipolar nanosecond pulsed power supply with 15 ns rising time is employed to generate an uniform dielectric barrier discharge using the wire-cylinder electrode configuration in atmospheric air. The images, waveforms of pulse voltage and discharge current, and the optical emission spectra of the discharges are recorded. The rotational and vibrational temperatures of plasma are determined by comparing the simulated spectra with the experimental spectra. The effects of pulse peak voltage, pulse repetition rate and quartz tube diameter on the emission intensities of N2 (C(3)Πu→B(3)Πg, 0-0) and N2(+)B(2)Σu(+)→X(2)Σg(+),0-0 and the rotational and vibrational temperatures have been investigated. It is found that the uniform plasma with low gas temperature can be obtained, and the emission intensities of N2 (C(3)Πu→B(3)Πg, 0-0) and N2(+)B(2)Σu(+)→X(2)Σg(+),0-0 rise with increasing the pulse peak voltage and pulse repetition rate, while decrease as the increase of quartz tube diameter. In addition, under the condition of 28 kV pulse peak voltage, 150 Hz pulse repetition rate and 7 mm quartz tube diameter, the plasma gas temperature is determined to be 330 K. The results also indicate that the plasma gas temperature keep almost constant when increasing the pulse peak voltage and pulse repetition rate but increase with the increase of the quartz tube diameter.

  20. Chemical and structural indicators for large redox potentials in Fe-based positive electrode materials.

    PubMed

    Melot, Brent C; Scanlon, David O; Reynaud, Marine; Rousse, Gwenaëlle; Chotard, Jean-Noël; Henry, Marc; Tarascon, Jean-Marie

    2014-07-23

    Li-ion batteries have enabled a revolution in the way portable consumer-electronics are powered and will play an important role as large-scale electrochemical storage applications like electric vehicles and grid-storage are developed. The ability to identify and design promising new positive insertion electrodes will be vital in continuing to push Li-ion technology to its fullest potential. Utilizing a combination of computational tools and structural analysis, we report new indicators which will facilitate the recognition of phases with the desired redox potential. Most importantly of these, we find there is a strong correlation between the presence of Li ions sitting in close-proximity to the redox center of polyanionic phases and the open circuit voltage in Fe-based cathodes. This common structural feature suggests that the bonding associated with Li may have a secondary inductive effect which increases the ionic character of Fe bonds beyond what is typically expected based purely on arguments of electronegativity associated with the polyanionic group. This correlation is supported by ab initio calculations which show the Bader charge increases (reflecting an increased ionicity) in a nearly linear fashion with the experimental cell potentials. These features are demonstrated to be consistent across a wide variety of compositions and structures and should help to facilitate the design of new, high-potential, and environmentally sustainable insertion electrodes.

  1. In-situ Spectroscopic and Structural Studies of Electrode Materials for Advanced Battery Applications

    SciTech Connect

    Daniel A Scherson

    2013-03-14

    Techniques have been developed and implemented to gain insight into fundamental factors that affect the performance of electrodes in Li and Li-ion batteries and other energy storage devices. These include experimental strategies for monitoring the Raman scattering spectra of single microparticles of carbon and transition metal oxides as a function of their state of charge. Measurements were performed in electrolytes of direct relevance to Li and Li-Ion batteries both in the static and dynamic modes. In addition, novel strategies were devised for performing conventional experiments in ultrahigh vacuum environments under conditions which eliminate effects associated with presence of impurities, using ultrapure electrolytes, both of the polymeric and ionic liquid type that display no measurable vapor pressure. Also examined was the reactivity of conventional non aqueous solvent toward ultrapure Li films as monitored in ultrahigh vacuum with external reflection Fourier transform infrared spectroscopy. Also pursued were efforts toward developing applying Raman-scattering for monitoring the flow of charge of a real Li ion battery. Such time-resolved, spatially-resolved measurements are key to validating the results of theoretical simulations involving real electrode structures.

  2. High-energy metal air batteries

    DOEpatents

    Zhang, Ji-Guang; Xiao, Jie; Xu, Wu; Wang, Deyu; Williford, Ralph E.; Liu, Jun

    2013-07-09

    Disclosed herein are embodiments of lithium/air batteries and methods of making and using the same. Certain embodiments are pouch-cell batteries encased within an oxygen-permeable membrane packaging material that is less than 2% of the total battery weight. Some embodiments include a hybrid air electrode comprising carbon and an ion insertion material, wherein the mass ratio of ion insertion material to carbon is 0.2 to 0.8. The air electrode may include hydrophobic, porous fibers. In particular embodiments, the air electrode is soaked with an electrolyte comprising one or more solvents including dimethyl ether, and the dimethyl ether subsequently is evacuated from the soaked electrode. In other embodiments, the electrolyte comprises 10-20% crown ether by weight.

  3. High-energy metal air batteries

    SciTech Connect

    Zhang, Ji-Guang; Xiao, Jie; Xu, Wu; Wang, Deyu; Williford, Ralph E.; Liu, Jun

    2014-07-01

    Disclosed herein are embodiments of lithium/air batteries and methods of making and using the same. Certain embodiments are pouch-cell batteries encased within an oxygen-permeable membrane packaging material that is less than 2% of the total battery weight. Some embodiments include a hybrid air electrode comprising carbon and an ion insertion material, wherein the mass ratio of ion insertion material to carbon is 0.2 to 0.8. The air electrode may include hydrophobic, porous fibers. In particular embodiments, the air electrode is soaked with an electrolyte comprising one or more solvents including dimethyl ether, and the dimethyl ether subsequently is evacuated from the soaked electrode. In other embodiments, the electrolyte comprises 10-20% crown ether by weight.

  4. Quantifying protein adsorption and function at nanostructured materials: enzymatic activity of glucose oxidase at GLAD structured electrodes.

    PubMed

    Jensen, Uffe B; Ferapontova, Elena E; Sutherland, Duncan S

    2012-07-31

    Nanostructured materials strongly modulate the behavior of adsorbed proteins; however, the characterization of such interactions is challenging. Here we present a novel method combining protein adsorption studies at nanostructured quartz crystal microbalance sensor surfaces (QCM-D) with optical (surface plasmon resonance SPR) and electrochemical methods (cyclic voltammetry CV) allowing quantification of both bound protein amount and activity. The redox enzyme glucose oxidase is studied as a model system to explore alterations in protein functional behavior caused by adsorption onto flat and nanostructured surfaces. This enzyme and such materials interactions are relevant for biosensor applications. Novel nanostructured gold electrode surfaces with controlled curvature were fabricated using colloidal lithography and glancing angle deposition (GLAD). The adsorption of enzyme to nanostructured interfaces was found to be significantly larger compared to flat interfaces even after normalization for the increased surface area, and no substantial desorption was observed within 24 h. A decreased enzymatic activity was observed over the same period of time, which indicates a slow conformational change of the adsorbed enzyme induced by the materials interface. Additionally, we make use of inherent localized surface plasmon resonances in these nanostructured materials to directly quantify the protein binding. We hereby demonstrate a QCM-D-based methodology to quantify protein binding at complex nanostructured materials. Our approach allows label free quantification of protein binding at nanostructured interfaces.

  5. Structural and microstructural characterization and properties of new phases in the Nd-Sr-Co-(Fe/Mn)-O system as air-electrodes in SOFCs.

    PubMed

    Boulahya, K; Muñoz Gil, D; Hassan, M; García Martin, S; Amador, U

    2017-01-24

    New oxides of the (NdSr)n+1MO3n+1 (M = Co and Mn or Fe) series are reported. Compounds of composition NdSrCo0.75Fe0.25O4.10, NdSrCo0.75Mn0.25O4.08 and Nd0.5Sr1.5Co0.75Mn0.25O3.86 are the n = 1 members of the Ruddlesden-Popper homologous series (K2NiF4 structural type) as determined by X-ray diffraction and different transmission electron microscopy techniques. Their crystal structure consists of connected (Co-Fe/Mn)O6 octahedra blocks separated by (Nd/Sr)O rock-salt like layers along the c-axis. Interstitial oxygen atoms or anion vacancies are induced depending on composition. Oxides with interstitial oxygen show good performances as intermediate temperature solid oxide fuel cell (IT-SOFC) cathode. The area-specific resistance values of electrodes made of these oxides at 973 K in air are 0.18 Ω cm(2) for NdSrCo0.75Fe0.25O4.10 and NdSrCo0.75Mn0.25O4.08 (comparable to the one of the state-of-the-art materials proposed as cathodes in IT-SOFC), and 1.38 Ω cm(2) for Nd0.5Sr1.5Co0.75Mn0.25O3.86.

  6. A facile synthesis of graphene foam as electrode material for supercapacitor

    NASA Astrophysics Data System (ADS)

    Sivaprakash, S.; Sivaprakash, Prabhavathy

    2016-07-01

    We report here a versatile fabrication approach of graphene foam (GF) with three dimensional (3D) porous conductive networks which reveal great potential for application in energy storage devices. This facile fabrication technique is believed to be favorable for supercapacitor application as the 3D-GF comprises conductive continuous porous networks with large active surface area. Supercapacitors utilize this high surface area electrode to attain improved capacitance. The resulting graphene foam exhibited satisfactory double layer capacitive behavior with improved electrochemical performance having good electrochemical cycling stability and high specific capacitance of 310 F g-1 at current density of 5 A g-1 and 160 F g-1 at current density of 20 A g-1.

  7. Metal hydrides used as negative electrode materials for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Sartori, Sabrina; Cuevas, Fermin; Latroche, Michel

    2016-02-01

    Energy is a key issue for future generation. Researches are conducted worldwide to develop new efficient means for energy conversion and storage. Electrochemical storage is foreseen as an efficient way to handle intermittent renewable energy production. The most advanced batteries are nowadays based on lithium-ion technology though their specific capacities should be significantly increased to bring solution to mass storage. Conversion reactions are one way to step forward larger capacities at the anode. We here review the possibility to use metallic or complex hydrides as negative electrode using conversion reaction of hydride with lithium. Moreover, promising alloying of lithium with the metallic species might provide additional reversible capacities. Both binary and ternary systems are reviewed and results are compared in the frame of the electrochemical application.

  8. TiO2(B) nanoribbons as negative electrode material for lithium ion batteries with high rate performance.

    PubMed

    Beuvier, Thomas; Richard-Plouet, Mireille; Mancini-Le Granvalet, Maryline; Brousse, Thierry; Crosnier, Olivier; Brohan, Luc

    2010-09-20

    Nanosized TiO(2)(B) has been investigated as a possible candidate to replace Li(4)Ti(5)O(12) or graphite as the negative electrode for a Li-ion battery. Nanoribbon precursors, classically synthesized in autogenous conditions at temperatures higher than 170 °C in alkaline medium, have been obtained, under reflux (T ∼ 120 °C, P = 1 bar). After ionic exchange, these nanoribbons exhibit a surface area of 140 m(2) g(-1), larger than those obtained under autogenous conditions or by solid state chemistry. These nanoparticles transform after annealing to isomorphic titanium dioxide. They mainly crystallize as the TiO(2)(B) variety with only 5% of anatase. This quantification of the anatase/TiO(2)(B) ratio was deduced from Raman spectroscopy measurement. TEM analysis highlights the excellent crystallinity of the nanosized TiO(2)(B), crystallizing as 6 nm thin nanoribbons. These characteristics are essential in lithium batteries for a fast lithium ion solid state diffusion into the active material. In lithium batteries, the TiO(2)(B) nanoribbons exhibit a good capacity and an excellent rate capability (reversible capacity of 200 mA h g(-1) at C/3 rate (111 mA g(-1)), 100 mA h g(-1) at 15C rate (5030 mA g(-1)) for a 50% carbon black loaded electrode). The electrode formulation study highlights the importance of the electronic and ionic connection around the active particles. The cycleability of the nano-TiO(2)(B) is another interesting point with a capacity loss of 5% only, over 500 cycles at 3C.

  9. Solid-state sodium batteries using polymer electrolytes and sodium intercalation electrode materials

    SciTech Connect

    Ma, Y. |

    1996-08-01

    Solid-state sodium cells using polymer electrolytes (polyethylene oxide mixed with sodium trifluoromethanesulfonate: PEO{sub n}NaCF{sub 3}SO{sub 3}) and sodium cobalt oxide positive electrodes are characterized in terms of discharge and charge characteristics, rate capability, cycle life, and energy and power densities. The P2 phase Na{sub x}CoO{sub 2} can reversibly intercalate sodium in the range of x = 0.3 to 0.9, giving a theoretical specific energy of 440 Wh/kg and energy density of 1,600 Wh/l. Over one hundred cycles to 60% depth of discharge have been obtained at 0.5 mA/cm{sup 2}. Experiments show that the electrolyte/Na interface is stable and is not the limiting factor to cell cycle life. Na{sub 0.7}CoO{sub 2} composite electrodes containing various amounts of carbon black additive are investigated. The transport properties of polymer electrolytes are the critical factors for performance. These properties (the ionic conductivity, salt diffusion coefficient, and ion transference number) are measured for the PEO{sub n}NaCF{sub 3}SO{sub 3} system over a wide range of concentrations at 85 C. All the three transport properties are very salt-concentration dependent. The ionic conductivity exhibits a maximum at about n = 20. The transference number, diffusion coefficient, and thermodynamic factor all vary with salt concentration in a similar fashion, decreasing as the concentration increases, except for a local maximum. These results verify that polymer electrolytes cannot be treated as ideal solutions. The measured transport-property values are used to analyze and optimize the electrolytes by computer simulation and also cell testing. Salt precipitation is believed to be the rate limiting process for cells using highly concentrated solutions, as a result of lower values of these properties, while salt depletion is the limiting factor when a dilute solution is used.

  10. Insulated ECG electrodes

    NASA Technical Reports Server (NTRS)

    Portnoy, W. M.; David, R. M.

    1973-01-01

    Insulated, capacitively coupled electrode does not require electrolyte paste for attachment. Other features of electrode include wide range of nontoxic material that may be employed for dielectric because of sputtering technique used. Also, electrode size is reduced because there is no need for external compensating networks with FET operational amplifier.

  11. Aerospace electrode line

    NASA Astrophysics Data System (ADS)

    Miller, L.

    1980-04-01

    A facility which produces electrodes for spacecraft power supplies is described. The electrode assembly procedures are discussed. A number of design features in the production process are reported including a batch operation mode and an independent equipment module design approach for transfering the electrode materials from process tank to process tank.

  12. Impact of varying area of polluting surface materials on perceived air quality.

    PubMed

    Sakr, W; Knudsen, H N; Gunnarsen, L; Haghighat, F

    2003-06-01

    A laboratory study was performed to investigate the impact of the concentration of pollutants in the air on emissions from building materials. Building materials were placed in ventilated test chambers. The experimental set-up allowed the concentration of pollution in the exhaust air to be changed either by diluting exhaust air with clean air (changing the dilution factor) or by varying the area of the material inside the chamber when keeping the ventilation rate constant (changing the area factor). Four different building materials and three combinations of two or three building materials were studied in ventilated small-scale test chambers. Each individual material and three of their combinations were examined at four different dilution factors and four different area factors. An untrained panel of 23 subjects assessed the air quality from the chambers. The results show that a certain increase in dilution improves the perceived air quality more than a similar decrease in area. The reason for this may be that the emission rate of odorous pollutants increases when the concentration in the chamber decreases. The results demonstrate that, in some cases the effect of increased ventilation on the air quality may be less than expected from a simple dilution model.

  13. High frequency reference electrode

    DOEpatents

    Kronberg, James W.

    1994-01-01

    A high frequency reference electrode for electrochemical experiments comprises a mercury-calomel or silver-silver chloride reference electrode with a layer of platinum around it and a layer of a chemically and electrically resistant material such as TEFLON around the platinum covering all but a small ring or "halo" at the tip of the reference electrode, adjacent to the active portion of the reference electrode. The voltage output of the platinum layer, which serves as a redox electrode, and that of the reference electrode are coupled by a capacitor or a set of capacitors and the coupled output transmitted to a standard laboratory potentiostat. The platinum may be applied by thermal decomposition to the surface of the reference electrode. The electrode provides superior high-frequency response over conventional electrodes.

  14. High frequency reference electrode

    DOEpatents

    Kronberg, J.W.

    1994-05-31

    A high frequency reference electrode for electrochemical experiments comprises a mercury-calomel or silver-silver chloride reference electrode with a layer of platinum around it and a layer of a chemically and electrically resistant material such as TEFLON around the platinum covering all but a small ring or halo' at the tip of the reference electrode, adjacent to the active portion of the reference electrode. The voltage output of the platinum layer, which serves as a redox electrode, and that of the reference electrode are coupled by a capacitor or a set of capacitors and the coupled output transmitted to a standard laboratory potentiostat. The platinum may be applied by thermal decomposition to the surface of the reference electrode. The electrode provides superior high-frequency response over conventional electrodes. 4 figs.

  15. 77 FR 17394 - Hazardous Materials: Approval and Communication Requirements for the Safe Transportation of Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-26

    ... transportation of hazardous materials by highway, rail, vessel, and air. The scope of the HMR includes hazardous.... Congress expressly authorized DOT to issue variances in the Hazardous Materials Transportation Act of 1975... include: The safety record for hazardous materials transported; transportation operations......

  16. Solid-State Electrode Engineering and Material Processing for All-Solid-State Lithium and Lithium-Ion Batteries

    NASA Astrophysics Data System (ADS)

    Yersak, Thomas A.

    In this dissertation we demonstrate the full rechargeability of a FeS 2/lithium metal battery at 60°C. To enable the reversibility of the FeS2 redox chemistry we utilize a bulk all-solid-state battery architecture based upon the Li2S-P2S5 glass-ceramic electrolyte. The glass-ceramic electrolyte's non-volatility and non-flammability allows us to use a lithium metal anode safely, while its solid nature confines FeS2's intermediate electroactive species to prevent active material loss and capacity fade. Based only on the weight of the active materials our battery stands to triple the specific energy (Wh kg-1) of conventional state-of-the-art Li-ion batteries. We also observe ortho-FeS2 as a charge product and propose a new discharge mechanism which revises 30 years of research on the subject. Unfortunately, our laboratory FeS2/Li battery could not achieve a practical cell-level specific energy because the composite electrode was nearly 70 wt. % glass-ceramic electrolyte and carbon black. We also found that our batteries were not durable because the formation of lithium dendrites through the glass-ceramic electrolyte separator membrane frequently internally shorted test cells upon charge. The remainder of this dissertation outlines our work to develop an all-solid-state Li-ion battery to address the shorting issue and the work done to engineer better active material-electrolyte solid-solid interfaces in the composite electrode for high cell-level specific energy.

  17. Magnetohydrodynamic electrode

    DOEpatents

    Marchant, David D.; Killpatrick, Don H.

    1978-01-01

    An electrode capable of withstanding high temperatures and suitable for use as a current collector in the channel of a magnetohydrodynamic (MHD) generator consists of a sintered powdered metal base portion, the upper surface of the base being coated with a first layer of nickel aluminide, an intermediate layer of a mixture of nickel aluminide - refractory ceramic on the first layer and a third or outer layer of a refractory ceramic material on the intermediate layer. The sintered powdered metal base resists spalling by the ceramic coatings and permits greater electrode compliance to thermal shock. The density of the powdered metal base can be varied to allow optimization of the thermal conductivity of the electrode and prevent excess heat loss from the channel.

  18. Silver decorated LaMnO3 nanorod/graphene composite electrocatalysts as reversible metal-air battery electrodes

    NASA Astrophysics Data System (ADS)

    Hu, Jie; Liu, Qiunan; Shi, Lina; Shi, Ziwei; Huang, Hao

    2017-04-01

    Perovskite LaMnO3 nanorod/reduced graphene oxides (LMO-NR/RGO) decorated with Ag nanoparticles are studied as a bifunctional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline electrolyte. LMO-NR/RGO composites are synthesized by using cetyltrimethyl ammonium bromide (CTAB) as template via a simple hydrothermal reaction followed by heat treatment; overlaying of Ag nanoparticles is obtained through a traditional silver mirror reaction. Electron microscopy reveals that LMO-NR is embedded between the sheets of RGO, and the material is homogeneously overlaid with Ag nanoparticles. The unique composite morphology of Ag/LMO-NR/RGO not only enhances the electron transport property by increasing conductivity but also facilitates the diffusion of electrolytes and oxygen. As confirmed by electrochemical testing, Ag/LMO-NR/RGO exhibits very strong synergy with Ag nanoparticles, LMO-NR, and RGO, and the catalytic activities of Ag/LMO-NR/RGO during ORR and OER are significantly improved. With the novel catalyst, the homemade zinc-air battery can be reversibly charged and discharged and display a stable cycle performance, indicating the great potential of this composite as an efficient bifunctional electrocatalyst for metal-air batteries.

  19. Nonlinear air-coupled emission: The signature to reveal and image microdamage in solid materials

    SciTech Connect

    Solodov, Igor; Busse, Gerd

    2007-12-17

    It is shown that low-frequency elastic vibrations of near-surface planar defects cause high-frequency ultrasonic radiation in surrounding air. The frequency conversion mechanism is concerned with contact nonlinearity of the defect vibrations and provides efficient generation of air-coupled higher-order ultraharmonics, ultrasubharmonics, and combination frequencies. The nonlinear air-coupled ultrasonic emission is applied for location and high-resolution imaging of damage-induced defects in a variety of solid materials.

  20. Reduced graphene oxide/macrocyclic iron complex hybrid materials as counter electrodes for dye-sensitized solar cells.

    PubMed

    Tsai, Chih-Hung; Huang, Wei-Chih; Wang, Wun-Shiuan; Shih, Chun-Jyun; Chi, Wen-Feng; Hu, Yu-Chung; Yu, Yuan-Hsiang

    2017-06-01

    A novel series of reduced graphene oxide (RGO)/macrocyclic iron (Fe) complex hybrid materials were synthesized and then used in the production of counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The electrode properties of various CEs were comprehensively analyzed using scanning electron microscopy, transmission electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, Raman spectroscopy, X-ray diffraction, and cyclic voltammetry analyses. DSSCs, based on various CEs, were characterized using current density-voltage, incident monochromatic photon-to-current conversion efficiency, and electrochemical impedance spectroscopy measurements. DSSCs fabricated using the RGO/macrocyclic Fe nanocomposite CEs yielded an efficiency of 6.75%. The RGO/Fe CEs exhibited efficient electrocatalytic capability because catalytic Fe particles were uniformly distributed on the surface of RGO. The results indicated that a DSSC with a RGO/Fe CE can exhibit an efficiency comparable to that of a platinum (Pt) CE DSSC and can therefore replace conventional Pt CE DSSCs to lower the cost of solar cells.

  1. Influences of internal resistance and specific surface area of electrode materials on characteristics of electric double layer capacitors

    NASA Astrophysics Data System (ADS)

    Suda, Yoshiyuki; Mizutani, Akitaka; Harigai, Toru; Takikawa, Hirofumi; Ue, Hitoshi; Umeda, Yoshito

    2017-01-01

    We fabricated electric double layer capacitors (EDLCs) using particulate and fibrous types of carbon nanomaterials with a wide range of specific surface areas and resistivity as an active material. The carbon nanomaterials used in this study are carbon nanoballoons (CNBs), onion-like carbon (OLC), and carbon nanocoils (CNCs). A commercially used activated carbon (AC) combined with a conductive agent was used as a comparison. We compared the EDLC performance using cyclic voltammetry (CV), galvanostatic charge/discharge testing, and electrochemical impedance spectroscopy (EIS). OLC showed a poor EDLC performance, although it has the lowest resistivity among the carbon nanomaterials. CNB, which has a 1/16 lower specific surface area than AC but higher specific surface area than CNC and OLC, had a higher specific capacitance than CNC and OLC. Moreover, at current densities of 1.5 Ag-1 and larger, the specific capacitance of the EDLC using CNB was almost the same as that using AC. Electrochemical impedance spectroscopy of the EDLCs revealed that the CNB and CNC electrodes had a much lower internal resistance than the AC electrode, which correlated with a low capacitance maintenance factor as the current density increased.

  2. In situ observation of nickel as an oxidizable electrode material for the solid-electrolyte-based resistive random access memory

    SciTech Connect

    Sun, Jun; Wu, Xing; Xu, Feng; Xu, Tao; Sun, Litao; Liu, Qi; Xie, Hongwei; Long, Shibing; Lv, Hangbing; Li, Yingtao; Liu, Ming

    2013-02-04

    In this letter, we dynamically investigate the resistive switching characteristics and physical mechanism of the Ni/ZrO{sub 2}/Pt device. The device shows stable bipolar resistive switching behaviors after forming process, which is similar to the Ag/ZrO{sub 2}/Pt and Cu/ZrO{sub 2}/Pt devices. Using in situ transmission electron microscopy, we observe in real time that several conductive filaments are formed across the ZrO{sub 2} layer between Ni and Pt electrodes after forming. Energy-dispersive X-ray spectroscopy results confirm that Ni is the main composition of the conductive filaments. The ON-state resistance increases with increasing temperature, exhibiting the feature of metallic conduction. In addition, the calculated resistance temperature coefficient is equal to that of the 10-30 nm diameter Ni nanowire, further indicating that the nanoscale Ni conductive bridge is the physical origin of the observed conductive filaments. The resistive switching characteristics and the conductive filament's component of Ni/ZrO{sub 2}/Pt device are consistent with the characteristics of the typical solid-electrolyte-based resistive random access memory. Therefore, aside from Cu and Ag, Ni can also be used as an oxidizable electrode material for resistive random access memory applications.

  3. Direct Observation of Active Material Concentration Gradients and Crystallinity Breakdown in LiFePO4 Electrodes During Charge/Discharge Cycling of Lithium Batteries

    PubMed Central

    2014-01-01

    The phase changes that occur during discharge of an electrode comprised of LiFePO4, carbon, and PTFE binder have been studied in lithium half cells by using X-ray diffraction measurements in reflection geometry. Differences in the state of charge between the front and the back of LiFePO4 electrodes have been visualized. By modifying the X-ray incident angle the depth of penetration of the X-ray beam into the electrode was altered, allowing for the examination of any concentration gradients that were present within the electrode. At high rates of discharge the electrode side facing the current collector underwent limited lithium insertion while the electrode as a whole underwent greater than 50% of discharge. This behavior is consistent with depletion at high rate of the lithium content of the electrolyte contained in the electrode pores. Increases in the diffraction peak widths indicated a breakdown of crystallinity within the active material during cycling even during the relatively short duration of these experiments, which can also be linked to cycling at high rate. PMID:24790684

  4. Direct Observation of Active Material Concentration Gradients and Crystallinity Breakdown in LiFePO4 Electrodes During Charge/Discharge Cycling of Lithium Batteries.

    PubMed

    Roberts, Matthew R; Madsen, Alex; Nicklin, Chris; Rawle, Jonathan; Palmer, Michael G; Owen, John R; Hector, Andrew L

    2014-04-03

    The phase changes that occur during discharge of an electrode comprised of LiFePO4, carbon, and PTFE binder have been studied in lithium half cells by using X-ray diffraction measurements in reflection geometry. Differences in the state of charge between the front and the back of LiFePO4 electrodes have been visualized. By modifying the X-ray incident angle the depth of penetration of the X-ray beam into the electrode was altered, allowing for the examination of any concentration gradients that were present within the electrode. At high rates of discharge the electrode side facing the current collector underwent limited lithium insertion while the electrode as a whole underwent greater than 50% of discharge. This behavior is consistent with depletion at high rate of the lithium content of the electrolyte contained in the electrode pores. Increases in the diffraction peak widths indicated a breakdown of crystallinity within the active material during cycling even during the relatively short duration of these experiments, which can also be linked to cycling at high rate.

  5. Magnetic control of electrochemical processes at electrode surface using iron-rich graphene materials with dual functionality.

    PubMed

    Lim, Chee Shan; Ambrosi, Adriano; Sofer, Zdeněk; Pumera, Martin

    2014-07-07

    Metal-doped graphene hybrid materials demonstrate promising capabilities in catalysis and various sensing applications. There also exists great interest for on-demand control of the selectivity of many electrochemical processes. In this work, an iron-doped thermally reduced graphene oxide (Fe-TRGO) was prepared and used to investigate the possibility of a reproducible, magnetically controlled method to modulate electrochemical reactivities through a scalable method. We made use of the presence of both magnetic and electrocatalytic properties in the Fe-TRGOs to induce attraction and removal of the Fe-TRGO material onto and off the working electrode surfaces magnetically, thereby controlling the electrochemical oxidation and reduction processes. The outstanding electrochemical performance of the Fe-TRGO material was evident, with enhanced current signals and lower peak potentials observed upon magnetic activation. Reversible and reproducible cycles of activation and deactivation were obtained as the peak heights and peak potentials remained relatively consistent with no apparent carryover between every step. Both components of Fe-TRGO play an electrocatalytic role in the electrochemical sensing. In the cases of the oxygen reduction reaction and reduction of cumene hydroperoxide, the iron oxide plays the role of an electrocatalyst, while in the cases of ascorbic acid, the enhanced electroactivity originates from the high surface area of the graphene portion in the Fe-TRGO hybrid material. The feasibility of this magnetically switchable method for on-demand sensing and energy production thus brings about potential developments for future electrochemical applications.

  6. Magnetic control of electrochemical processes at electrode surface using iron-rich graphene materials with dual functionality

    NASA Astrophysics Data System (ADS)

    Lim, Chee Shan; Ambrosi, Adriano; Sofer, Zdeněk; Pumera, Martin

    2014-06-01

    Metal-doped graphene hybrid materials demonstrate promising capabilities in catalysis and various sensing applications. There also exists great interest for on-demand control of the selectivity of many electrochemical processes. In this work, an iron-doped thermally reduced graphene oxide (Fe-TRGO) was prepared and used to investigate the possibility of a reproducible, magnetically controlled method to modulate electrochemical reactivities through a scalable method. We made use of the presence of both magnetic and electrocatalytic properties in the Fe-TRGOs to induce attraction and removal of the Fe-TRGO material onto and off the working electrode surfaces magnetically, thereby controlling the electrochemical oxidation and reduction processes. The outstanding electrochemical performance of the Fe-TRGO material was evident, with enhanced current signals and lower peak potentials observed upon magnetic activation. Reversible and reproducible cycles of activation and deactivation were obtained as the peak heights and peak potentials remained relatively consistent with no apparent carryover between every step. Both components of Fe-TRGO play an electrocatalytic role in the electrochemical sensing. In the cases of the oxygen reduction reaction and reduction of cumene hydroperoxide, the iron oxide plays the role of an electrocatalyst, while in the cases of ascorbic acid, the enhanced electroactivity originates from the high surface area of the graphene portion in the Fe-TRGO hybrid material. The feasibility of this magnetically switchable method for on-demand sensing and energy production thus brings about potential developments for future electrochemical applications.

  7. Compartmented electrode structure

    DOEpatents

    Vissers, Donald R.; Shimotake, Hiroshi; Gay, Eddie C.; Martino, Fredric J.

    1977-06-14

    Electrodes for secondary electrochemical cells are provided with compartments for containing particles of the electrode reactant. The compartments are defined by partitions that are generally impenetrable to the particles of reactant and, in some instances, to the liquid electrolyte used in the cell. During cycling of the cell, reactant material initially loaded into a particular compartment is prevented from migrating and concentrating within the lower portion of the electrode or those portions of the electrode that exhibit reduced electrical resistance.

  8. Hierarchical Heterostructures of NiCo2O4@XMoO4 (X = Ni, Co) as an Electrode Material for High-Performance Supercapacitors

    NASA Astrophysics Data System (ADS)

    Hu, Jiyu; Qian, Feng; Song, Guosheng; Wang, Linlin

    2016-05-01

    Hierarchical heterostructures of NiCo2O4@XMoO4 (X = Ni, Co) were developed as an electrode material for supercapacitor with improved pseudocapacitive performance. Within these hierarchical heterostructures, the mesoporous NiCo2O4 nanosheet arrays directly grown on the Ni foam can not only act as an excellent pseudocapacitive material but also serve as a hierarchical scaffold for growing NiMoO4 or CoMoO4 electroactive materials (nanosheets). The electrode made of NiCo2O4@NiMoO4 presented a highest areal capacitance of 3.74 F/cm2 at 2 mA/cm2, which was much higher than the electrodes made of NiCo2O4@CoMoO4 (2.452 F/cm2) and NiCo2O4 (0.456 F/cm2), respectively. Meanwhile, the NiCo2O4@NiMoO4 electrode exhibited good rate capability. It suggested the potential of the hierarchical heterostructures of NiCo2O4@CoMoO4 as an electrode material in supercapacitors.

  9. Hierarchical Heterostructures of NiCo2O4@XMoO4 (X = Ni, Co) as an Electrode Material for High-Performance Supercapacitors.

    PubMed

    Hu, Jiyu; Qian, Feng; Song, Guosheng; Wang, Linlin

    2016-12-01

    Hierarchical heterostructures of NiCo2O4@XMoO4 (X = Ni, Co) were developed as an electrode material for supercapacitor with improved pseudocapacitive performance. Within these hierarchical heterostructures, the mesoporous NiCo2O4 nanosheet arrays directly grown on the Ni foam can not only act as an excellent pseudocapacitive material but also serve as a hierarchical scaffold for growing NiMoO4 or CoMoO4 electroactive materials (nanosheets). The electrode made of NiCo2O4@NiMoO4 presented a highest areal capacitance of 3.74 F/cm(2) at 2 mA/cm(2), which was much higher than the electrodes made of NiCo2O4@CoMoO4 (2.452 F/cm(2)) and NiCo2O4 (0.456 F/cm(2)), respectively. Meanwhile, the NiCo2O4@NiMoO4 electrode exhibited good rate capability. It suggested the potential of the hierarchical heterostructures of NiCo2O4@CoMoO4 as an electrode material in supercapacitors.

  10. Aerosol jet printed p- and n-type electrolyte-gated transistors with a variety of electrode materials: exploring practical routes to printed electronics.

    PubMed

    Hong, Kihyon; Kim, Se Hyun; Mahajan, Ankit; Frisbie, C Daniel

    2014-11-12

    Printing electrically functional liquid inks is a promising approach for achieving low-cost, large-area, additive manufacturing of flexible electronic circuits. To print thin-film transistors, a basic building block of thin-film electronics, it is important to have several options for printable electrode materials that exhibit high conductivity, high stability, and low-cost. Here we report completely aerosol jet printed (AJP) p- and n-type electrolyte-gated transistors (EGTs) using a variety of different electrode materials including highly conductive metal nanoparticles (Ag), conducting polymers (polystyrenesulfonate doped poly(3,4-ethylendedioxythiophene, PEDOT:PSS), transparent conducting oxides (indium tin oxide), and carbon-based materials (reduced graphene oxide). Using these source-drain electrode materials and a PEDOT:PSS/ion gel gate stack, we demonstrated all-printed p- and n-type EGTs in combination with poly(3-hexythiophene) and ZnO semiconductors. All transistor components (including electrodes, semiconductors, and gate insulators) were printed by AJP. Both kinds of devices showed typical p- and n-type transistor characteristics, and exhibited both low-threshold voltages (<2 V) and high hole and electron mobilities. Our assessment suggests Ag electrodes may be the best option in terms of overall performance for both types of EGTs.

  11. 5 CFR 842.405 - Air traffic controllers, firefighters, law enforcement officers, and nuclear materials couriers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... RETIREMENT SYSTEM-BASIC ANNUITY Computations § 842.405 Air traffic controllers, firefighters, law enforcement... 5 Administrative Personnel 2 2011-01-01 2011-01-01 false Air traffic controllers, firefighters, law enforcement officers, and nuclear materials couriers. 842.405 Section 842.405...

  12. 5 CFR 842.405 - Air traffic controllers, firefighters, law enforcement officers, and nuclear materials couriers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... RETIREMENT SYSTEM-BASIC ANNUITY Computations § 842.405 Air traffic controllers, firefighters, law enforcement... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Air traffic controllers, firefighters, law enforcement officers, and nuclear materials couriers. 842.405 Section 842.405...

  13. Material Properties from Air Puff Corneal Deformation by Numerical Simulations on Model Corneas

    PubMed Central

    Dorronsoro, Carlos; de la Hoz, Andrés; Marcos, Susana

    2016-01-01

    Objective To validate a new method for reconstructing corneal biomechanical properties from air puff corneal deformation images using hydrogel polymer model corneas and porcine corneas. Methods Air puff deformation imaging was performed on model eyes with artificial corneas made out of three different hydrogel materials with three different thicknesses and on porcine eyes, at constant intraocular pressure of 15 mmHg. The cornea air puff deformation was modeled using finite elements, and hyperelastic material parameters were determined through inverse modeling, minimizing the difference between the simulated and the measured central deformation amplitude and central-peripheral deformation ratio parameters. Uniaxial tensile tests were performed on the model cornea materials as well as on corneal strips, and the results were compared to stress-strain simulations assuming the reconstructed material parameters. Results The measured and simulated spatial and temporal profiles of the air puff deformation tests were in good agreement (< 7% average discrepancy). The simulated stress-strain curves of the studied hydrogel corneal materials fitted well the experimental stress-strain curves from uniaxial extensiometry, particularly in the 0–0.4 range. Equivalent Young´s moduli of the reconstructed material properties from air-puff were 0.31, 0.58 and 0.48 MPa for the three polymer materials respectively which differed < 1% from those obtained from extensiometry. The simulations of the same material but different thickness resulted in similar reconstructed material properties. The air-puff reconstructed average equivalent Young´s modulus of the porcine corneas was 1.3 MPa, within 18% of that obtained from extensiometry. Conclusions Air puff corneal deformation imaging with inverse finite element modeling can retrieve material properties of model hydrogel polymer corneas and real corneas, which are in good correspondence with those obtained from uniaxial extensiometry

  14. Interphase evolution at two promising electrode materials for Li-ion batteries: LiFePO4 and LiNi1/2 Mn1/2O2.

    PubMed

    Dupré, Nicolas; Cuisinier, Marine; Martin, Jean-Frederic; Guyomard, Dominique

    2014-07-21

    The present review reports the characterization and control of interfacial processes occurring on olivine LiFePO(4) and layered LiNi(1/2) Mn(1/2)O(2), standing here as model compounds, during storage and electrochemical cycling. The formation and evolution of the interphase created by decomposition of the electrolyte is investigated by using spectroscopic tools such as magic-angle-spinning nuclear magnetic resonance ((7)Li,(19)F and (31)P) and electron energy loss spectroscopy, in parallel to X-ray photoelectron spectroscopy, to quantitatively describe the interphase and unravel its architecture. The influence of the pristine surface chemistry of the active material is carefully examined. The importance of the chemical history of the surface of the electrode material before any electrochemical cycling and the strong correlation between interface phenomena, the formation/evolution of an interphase, and the electrochemical behavior appear clearly from the use of these combined characterization probes. This approach allows identifying interface aging and failure mechanisms. Different types of surface modifications are then investigated, such as intrinsic modifications upon aging in air or methods based on the use of additives in the electrolyte or carbon coatings on the surface of the active materials. In each case, the species detected on the surface of the materials during storage and cycling are correlated with the electrochemical performance of the modified positive electrodes.

  15. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  16. Influence of the temperature of electrode material on its disintegration under the action of an arc discharge in hydrogen

    NASA Technical Reports Server (NTRS)

    Bolotov, A. V.; Yukhimchuk, S. A.

    1985-01-01

    An analysis is made of the electrophysical processes occurring at the end surface of rod electrodes during constant and alternating arc discharge in hydrogen. Experiments are reported on the effect of surface temperature of tungsten electrodes on their erosion. The influence of activating additions of thorium oxide, the structure of the tungsten, and the gas surrounding the electrode on the specific thermal loading and the erosion of the electrodes is discussed.

  17. Electricity generation from young landfill leachate in a microbial fuel cell with a new electrode material.

    PubMed

    Özkaya, Bestamin; Cetinkaya, Afşin Yusuf; Cakmakci, Mehmet; Karadağ, Doğan; Sahinkaya, Erkan

    2013-04-01

    This study aims at evaluating the performance of a two-chambered continuously fed microbial fuel cell with new Ti-TiO₂ electrodes for bioelectricity generation from young landfill leachate at varying strength of wastewater (1-50 COD g/L) and hydraulic retention time (HRT, 0.25-2 days). The COD removal efficiency in the MFC increased with time and reached 45 % at full-strength leachate (50 g/L COD) feeding. The current generation increased with increasing leachate strength and decreasing HRT up to organic loading rate of 100 g COD/L/day. The maximum current density throughout the study was 11 A/m² at HRT of 0.5 day and organic loading rate of 67 g COD/L/day. Coulombic efficiency (CE) decreased from 57 % at feed COD concentration of 1 g/L to less than 1 % when feed COD concentration was 50 g/L. Increase in OLR resulted in increase in power output but decrease in CE.

  18. Electrochemical monitoring of biointeraction by graphene-based material modified pencil graphite electrode.

    PubMed

    Eksin, Ece; Zor, Erhan; Erdem, Arzum; Bingol, Haluk

    2017-06-15

    Recently, the low-cost effective biosensing systems based on advanced nanomaterials have received a key attention for development of novel assays for rapid and sequence-specific nucleic acid detection. The electrochemical biosensor based on reduced graphene oxide (rGO) modified disposable pencil graphite electrodes (PGEs) were developed herein for electrochemical monitoring of DNA, and also for monitoring of biointeraction occurred between anticancer drug, Daunorubicin (DNR), and DNA. First, rGO was synthesized chemically and characterized by using UV-Vis, TGA, FT-IR, Raman Spectroscopy and SEM techniques. Then, the quantity of rGO assembling onto the surface of PGE by passive adsorption was optimized. The electrochemical behavior of rGO-PGEs was examined by cyclic voltammetry (CV). rGO-PGEs were then utilized for electrochemical monitoring of surface-confined interaction between DNR and DNA using differential pulse voltammetry (DPV) technique. Additionally, voltammetric results were complemented with electrochemical impedance spectroscopy (EIS) technique. Electrochemical monitoring of DNR and DNA was resulted with satisfying detection limits 0.55µM and 2.71µg/mL, respectively.

  19. Combination of porous silica monolith and gold thin films for electrode material of supercapacitor

    NASA Astrophysics Data System (ADS)

    Pastre, A.; Cristini-Robbe, O.; Boé, A.; Raulin, K.; Branzea, D.; El Hamzaoui, H.; Kinowski, C.; Rolland, N.; Bernard, R.

    2015-12-01

    An all-solid electrical double layer supercapacitor was prepared, starting from a porous silica matrix coated with a gold thin-film. The metallization of the silica xerogel was performed by an original wet chemical process, based on the controlled growth of gold nanoparticles on two opposite faces of the silica monolith as a seed layer, followed by an electroless deposition of a continuous gold thin film. The thickness of the metallic thin film was assessed to be 700 nm. The silica plays two major roles: (1) it is used as a porous matrix for the gold electrode, creating a large specific surface area, and (2) it acts as a separator (non-metallized part of the silica). The silica monolith was soaked in a polyvinyl alcohol and phosphoric acid mixture which is used as polymer electrolyte. Capacitance effect was demonstrated by cyclic voltammetry experiments. The specific capacitance was found to be equal to 0.95 mF cm- 2 (9.5 F g-1). No major degradation occurs within more than 3000 cycles.

  20. Solid oxide fuel cell with single material for electrodes and interconnect

    DOEpatents

    McPheeters, Charles C.; Nelson, Paul A.; Dees, Dennis W.

    1994-01-01

    A solid oxide fuel cell having a plurality of individual cells. A solid oxide fuel cell has an anode and a cathode with electrolyte disposed therebetween, and the anode, cathode and interconnect elements are comprised of substantially one material.

  1. Partial conversion of current collectors into nickel copper oxide electrode materials for high-performance energy storage devices.

    PubMed

    Zhang, Liuyang; Gong, Hao

    2015-07-22

    A novel substrate sacrifice process is proposed and developed for converting part of a current collector into supercapacitor active materials, which provides a new route in achieving high energy density of supercapacitor device. Part of a copper foam current collector is successfully converted into highly porous nickel copper oxide electrode for light- and high-performance supercapacitors. Remarkably, this strategy circumvents the problem associated with poor contact interface between electrode and current collector. Meanwhile, the overall weight of the supercapacitor could be minimized. The charge transfer kinetics is improved while the advantage of the excellent mechanical properties of metal current collector is not traded off. By virtue of this unique current collector self-involved architecture, the material derived from the current collector manifests large areal capacitance of 3.13 F cm(-2) at a current density of 1 A g(-1). The capacitance can retain 2.97 F cm(-2) at a much higher density (4 A g(-1)). Only a small decay of 6.5% appears at 4 A g(-1) after 1600 cycles. The strategy reported here sheds light on new strategies in making additional use of the metal current collector. Furthermore, asymmetric supercapacitor using both solid-state gel electrolyte and liquid counterpart are obtained and analyzed. The liquid asymmetric supercapacitor can deliver a high energy density up to 0.5 mWh cm(-2) (53 Wh kg(-1)) at a power density of 13 mW cm(-2) (1.4 kW kg(-1)).

  2. Optimized spherical manganese oxide-ferroferric oxide-tin oxide ternary composites as advanced electrode materials for supercapacitors.

    PubMed

    Zhu, Jian; Tang, Shaochun; Vongehr, Sascha; Xie, Hao; Meng, Xiangkang

    2015-09-18

    Inexpensive MnO2 is a promising material for supercapacitors (SCs), but its application is limited by poor electrical conductivity and low specific surface area. We design and fabricate hierarchical MnO2-based ternary composite nanostructures showing superior electrochemical performance via doping with electrochemically active Fe3O4 in the interior and electrically conductive SnO2 nanoparticles in the surface layer. Optimization composition results in a MnO2-Fe3O4-SnO2 composite electrode material with 5.9 wt.% Fe3O4 and 5.3 wt.% SnO2, leading to a high specific areal capacitance of 1.12 F cm(-2) at a scan rate of 5 mV s(-1). This is two to three times the values for MnO2-based binary nanostructures at the same scan rate. The low amount of SnO2 almost doubles the capacitance of porous MnO2-Fe3O4 (before SnO2 addition), which is attributed to an improved conductivity and remaining porosity. In addition, the optimal ternary composite has a good rate capability and an excellent cycling performance with stable capacitance retention of ~90% after 5000 charge/discharge cycles at 7.5 mA cm(-2). All-solid-state SCs are assembled with such electrodes using polyvinyl alcohol/Na2SO4 electrolyte. An integrated device made by connecting two identical SCs in series can power a light-emitting diode indicator for more than 10 min.

  3. Development of dielectric barrier discharge-type ozone generator constructed with piezoelectric transformers: effect of dielectric electrode materials on ozone generation

    NASA Astrophysics Data System (ADS)

    Teranishi, Kenji; Shimomura, Naoyuki; Suzuki, Susumu; Itoh, Haruo

    2009-11-01

    The dependence of ozone generation on the types of dielectric electrode material has been investigated using an ozone generator constructed with the piezoelectric transformer developed in our laboratory. The ozone generator is based on the excitation of the dielectric barrier discharge (DBD), which has the advantage of a compact configuration for generating ozone. Four kinds of dielectric materials are prepared for dielectric barrier electrodes. Electrical properties of the DBD and the ozone generation characteristics are investigated for the different dielectric materials. Differences in the discharge mode among the barrier electrode materials are recognized and discussed on the basis of the results of the Lissajous figures and voltage-current waveforms. During the continuous running of the generator, a temporal decrease in ozone concentration is observed owing to the temperature increase inside the reactor. Although the ozone generation characteristics are influenced by many properties of dielectrics, two important factors for achieving high-efficiency ozone generation are identified in this study. One is the use of a high-thermal conductivity material for the dielectric electrode, which functions well as a heat sink for transferring the generated heat to the outside through the material. The other factor is the control of the discharge mode. Our results show that the discharge mode that is considered as Townsend-like DBD is suitable for high-efficiency ozone generation.

  4. Hierarchical micro- and mesoporous carbide-derived carbon as a high-performance electrode material in supercapacitors.

    PubMed

    Rose, Marcus; Korenblit, Yair; Kockrick, Emanuel; Borchardt, Lars; Oschatz, Martin; Kaskel, Stefan; Yushin, Gleb

    2011-04-18

    Ordered mesoporous carbide-derived carbon (OM-CDC) materials produced by nanocasting of ordered mesoporous silica templates are characterized by a bimodal pore size distribution with a high ratio of micropores. The micropores result in outstanding adsorption capacities and the well-defined mesopores facilitate enhanced kinetics in adsorption processes. Here, for the first time, a systematic study is presented, in which the effects of synthesis temperature on the electrochemical performance of these materials in supercapacitors based on a 1 M aqueous solution of sulfuric acid and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid are reported. Cyclic voltammetry shows the specific capacitance of the OM-CDC materials exceeds 200 F g(-1) in the aqueous electrolyte and 185 F g(-1) in the ionic liquid, when measured in a symmetric configuration in voltage ranges of up to 0.6 and 2 V, respectively. The ordered mesoporous channels in the produced OM-CDC materials serve as ion-highways and allow for very fast ionic transport into the bulk of the OM-CDC particles. At room temperature the enhanced ion transport leads to 75% and 90% of the capacitance retention at current densities in excess of ∼10 A g(-1) in ionic liquid and aqueous electrolytes, respectively. The supercapacitors based on 250-300 μm OM-CDC electrodes demonstrate an operating frequency of up to 7 Hz in aqueous electrolyte. The combination of high specific capacitance and outstanding rate capabilities of the OM-CDC materials is unmatched by state-of-the art activated carbons and strictly microporous CDC materials.

  5. Electrode Nanostructures in Lithium‐Based Batteries

    PubMed Central

    Mahmood, Nasir

    2014-01-01

    Lithium‐based batteries possessing energy densities much higher than those of the conventional batteries belong to the most promising class of future energy devices. However, there are some fundamental issues related to their electrodes which are big roadblocks in their applications to electric vehicles (EVs). Nanochemistry has advantageous roles to overcome these problems by defining new nanostructures of electrode materials. This review article will highlight the challenges associated with these chemistries both to bring high performance and longevity upon considering the working principles of the various types of lithium‐based (Li‐ion, Li‐air and Li‐S) batteries. Further, the review discusses the advantages and challenges of nanomaterials in nanostructured electrodes of lithium‐based batteries, concerns with lithium metal anode and the recent advancement in electrode nanostructures. PMID:27980896

  6. Electrode Nanostructures in Lithium-Based Batteries.

    PubMed

    Mahmood, Nasir; Hou, Yanglong

    2014-12-01

    Lithium-based batteries possessing energy densities much higher than those of the conventional batteries belong to the most promising class of future energy devices. However, there are some fundamental issues related to their electrodes which are big roadblocks in their applications to electric vehicles (EVs). Nanochemistry has advantageous roles to overcome these problems by defining new nanostructures of electrode materials. This review article will highlight the challenges associated with these chemistries both to bring high performance and longevity upon considering the working principles of the various types of lithium-based (Li-ion, Li-air and Li-S) batteries. Further, the review discusses the advantages and challenges of nanomaterials in nanostructured electrodes of lithium-based batteries, concerns with lithium metal anode and the recent advancement in electrode nanostructures.

  7. Nano-sized structured layered positive electrode materials to enable high energy density and high rate capability lithium batteries

    DOEpatents

    Deng, Haixia; Belharouak, Ilias; Amine, Khalil

    2012-10-02

    Nano-sized structured dense and spherical layered positive active materials provide high energy density and high rate capability electrodes in lithium-ion batteries. Such materials are spherical second particles made from agglomerated primary particles that are Li.sub.1+.alpha.(Ni.sub.xCo.sub.yMn.sub.z).sub.1-tM.sub.tO.sub.2-dR.sub.d- , where M is selected from can be Al, Mg, Fe, Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti, Zr, or a mixture of any two or more thereof, R is selected from F, Cl, Br, I, H, S, N, or a mixture of any two or more thereof, and 0.ltoreq..alpha..ltoreq.0.50; 0materials and their use in electrochemical devices are also described.

  8. Chemical and structural stability of lithium-ion battery electrode materials under electron beam.

    PubMed

    Lin, Feng; Markus, Isaac M; Doeff, Marca M; Xin, Huolin L

    2014-07-16

    The investigation of chemical and structural dynamics in battery materials is essential to elucidation of structure-property relationships for rational design of advanced battery materials. Spatially resolved techniques, such as scanning/transmission electron microscopy (S/TEM), are widely applied to address this challenge. However, battery materials are susceptible to electron beam damage, complicating the data interpretation. In this study, we demonstrate that, under electron beam irradiation, the surface and bulk of battery materials undergo chemical and structural evolution equivalent to that observed during charge-discharge cycling. In a lithiated NiO nanosheet, a Li2CO3-containing surface reaction layer (SRL) was gradually decomposed during electron energy loss spectroscopy (EELS) acquisition. For cycled LiNi(0.4)Mn(0.4)Co(0.18)Ti(0.02)O2 particles, repeated electron beam irradiation induced a phase transition from an layered structure to an rock-salt structure, which is attributed to the stoichiometric lithium and oxygen removal from 3a and 6c sites, respectively. Nevertheless, it is still feasible to preserve pristine chemical environments by minimizing electron beam damage, for example, using fast electron imaging and spectroscopy. Finally, the present study provides examples of electron beam damage on lithium-ion battery materials and suggests that special attention is necessary to prevent misinterpretation of experimental results.

  9. Molecular layer deposition of "vanadicone", a vanadium-based hybrid material, as an electrode for lithium-ion batteries.

    PubMed

    Van de Kerckhove, Kevin; Mattelaer, Felix; Dendooven, Jolien; Detavernier, Christophe

    2017-03-08

    Molecular layer deposition (MLD) of hybrid organic-inorganic thin films called "vanadicones" was investigated using tetrakisethylmethylaminovanadium (TEMAV) as the metal precursor and glycerol (GL) or ethylene glycol (EG) as the organic reactant. Linear and continued growth could only be achieved with GL as the organic reactant. The TEMAV/GL process displayed self-limiting reactions for both precursor and reactant pulses in the temperature range from 80 °C to 180 °C, with growth rates of 1.2 to 0.5 Å per cycle, respectively. Infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) revealed the hybrid nature of the films. From X-ray reflectivity, the density was estimated at 2.6 g cm(-3). A series of 21 nm vanadicone films were subjected to annealing under oxidizing (air) or inert (He) atmospheres at 500 °C. During annealing in air, the film crystallized to the V2O5 phase and all carbon was removed from the film. The films annealed in helium remained amorphous and retained most of their carbon content. Electrochemical measurements revealed lithium-ion activity during cyclic voltammetry in all treated films, while the as deposited film was inactive. In the 2.9 to 3.5 V vs. Li(+)/Li potential region, no improvement over the V2O5 reference was observed. However, the helium annealed samples outperformed V2O5 in terms of capacity, rate performance and cyclability when charged and discharged in the 1.0 to 3.5 V vs. Li(+)/Li region. This result enables the application of VxOy-based hybrid electrodes in a wider potential range without sacrificing the stability and performance.

  10. Effect of dielectric material on bipolar nanosecond pulse diffuse dielectric barrier discharge in air at atmospheric pressure.

    PubMed

    Tang, Kai; Wang, Wenchun; Yang, Dezheng; Zhang, Shuai; Yang, Yang; Liu, Zhijie

    2013-08-01

    In this paper, dielectric plates made by ceramic, quartz and polytetrafluoroethylene (PTFE) respectively are employed to generate low gas temperature, diffuse dielectric barrier discharge plasma by using a needle-plate electrode configuration in air at atmospheric pressure. Both discharge images and the optical emission spectra are obtained while ceramic, quartz and PTFE are used as dielectric material. Plasma gas temperature is also calculated by comparing the experimental emission spectra with the best fitted spectra of N2 (C(3)Πu→B(3)Πg 1-3) and N2 (C(3)Πu→B(3)Πg 0-2). The effects of different pulse peak voltages and gas gap distances on the emission intensity of N2 (C(3)Πu→B(3)Πg, 0-0, 337.1 nm) and the plasma area on dielectric surface are investigated while ceramic, quartz and PTFE are used as dielectric material. It is found that the permittivity of dielectric material plays an important role in the discharge homogeneity, plasma gas temperature, emission spectra intensity of the discharge, etc. Dielectric with higher permittivity i.e., ceramic means brighter discharge luminosity and stronger emission spectra intensity of N2 (C(3)Πu→B(3)Πg, 0-0, 337.1 nm) among the three dielectric materials. However, more homogeneous, larger plasma area on dielectric surface and lower plasma gas temperature can be obtained under dielectric with lower permittivity i.e., PTFE. The emission spectra intensity and plasma gas temperature of the discharge while the dielectric plate is made by quartz are smaller than that while ceramic is used as dielectric material and bigger than that when PTFE is used as dielectric material.

  11. Stabilization of battery electrodes through chemical pre-intercalation of layered materials

    NASA Astrophysics Data System (ADS)

    Clites, Mallory; Pomerantseva, Ekaterina

    2016-09-01

    Vanadium oxide with bilayered crystal structure shows high specific capacity in intercalation-based energy storage systems, such as Li-ion and Na-ion batteries. The enhanced charge storage ability is attributed to the high oxidation state of vanadium enabling intercalation of more than one Li+ (or Na+) ion per V2O5 unit cell. In addition, large interlayer spacing of 10-13 Å, typical for the bilayered vanadium oxide, is believed to lead to the facilitated diffusion of charge carrying ions further improving specific capacity of this material. However, we found that initial high capacity of the bilayered V2O5 notably decreases only after a few cycles. In this work, we show results of the capacity stabilization strategy based on inclusion of inorganic ions, other than lithium ion, between the structural layers using chemical pre-intercalation approach. These ions are believed to form bonds with the V-O layered framework improving structural stability of the material during electrochemical cycling, and therefore they are often called stabilizing ions. In this paper we report how electrochemical stability of the AxV2O5 (A = Na, K, Mg, Ca) cathode materials is correlated with the size and charge of the stabilizing ions. Li-preintercalated vanadium oxide (LixV2O5) served as the reference material in this study. We found that chemical insertion of doubly charged, small (r = 0.86 Å) Mg2+ stabilizing ion results in the highest capacity retention.

  12. Solid oxide fuel cell with single material for electrodes and interconnect

    DOEpatents

    McPheeters, C.C.; Nelson, P.A.; Dees, D.W.

    1994-07-19

    A solid oxide fuel cell is described having a plurality of individual cells. A solid oxide fuel cell has an anode and a cathode with electrolyte disposed there between, and the anode, cathode and interconnect elements are comprised of substantially one material. 9 figs.

  13. Structural phase transition and electrode characteristics of LiMn{sub 2{minus}x}Mg{sub x}O{sub 4} positive electrode material for the lithium secondary battery

    SciTech Connect

    Idemoto, Y.; Udagawa, K.; Koura, N.; Richardson, J. W., Jr.; Takeuchi, K.; Loong, C.-K.

    1999-12-10

    With in mind improving the cycle performance of 4V class lithium manganese oxide positive electrode material for the lithium secondary battery, the authors have been investigating the effects of partial substitution of Mn by another metal. The crystal phase transition in the quaternary spinel LiMn{sub 2{minus}x}Mg{sub x}O{sub 4} was studied by neutron powder diffraction at 200K and DSC measurements at low temperatures. They find that substituting Mn by Mg resulted in a more stable crystal structure with the Jahn-Teller transition suppressed down to low temperature. The charge-discharge characteristics of these positive electrode active materials were investigated at 4V range. Although the discharge capacity decreased with increasing Mg content, the cycle performance was improved with increasing Mg content.

  14. Study of structure and properties of oxide electrode materials (Fe3O4, AZO, SRO) and their device applications

    NASA Astrophysics Data System (ADS)

    Olga, Chichvarina

    Ferroelectric thin film capacitor heterostructures have attracted considerable attention in the last decade because of their potential applications in piezoelectric sensors, actuators, power generators and non-volatile memory devices. Strongly correlated all-perovskite oxide heterojunctions are of a particular interest, as their material properties (electronic, structural, magnetic and optical, etc.) can be tuned via doping, interface effect, applied electrical field, and formation of two-dimensional electron gas (2DEG), etc. The right selection of electrode material for this type of capacitor-like structures may modify and enhance the performance of a device, as the electrode/barrier layer interfaces can significantly influence its macroscopic properties. Although there is a number of reports on the effect of electrode interfaces on the properties of PZT capacitors deposited on SRO buffered STO substrate, very little is known about Fe3O4/PZT and AZO/PZT electrode interfaces. This thesis comprises two parts. In the first part we present a systematic study of the structural, transport, magnetic and optical properties of oxide thin films: AZO, Fe3O4 and SRO. These monolayers were fabricated via pulsed laser deposition technique on quartz, MgO and STO substrates respectively. The second part of this thesis elucidates the behaviour of these three oxides as electrode components in PZT/SRO/STO heteroepitaxial structures. The highlights of the work are summarized below: 1) Zinc-blende (ZB) phase of ZnO was predicted to possess higher values of conductivity and higher doping efficiency compared to its wurzite counterpart and thus has greater chances of facilitating the fabrication of ZnO-electrode-based devices. However, zinc-blende is a metastable phase, and it is challenging to obtain single-phase ZB. To tackle this challenge we tuned parameters such-as film thickness, substrate and annealing effect, and achieved a ZB phase of Ti-doped ZnO, ZB-(Zn1-xTix)O thin film. An

  15. Igniter electrode life control

    SciTech Connect

    Scott, J.C.

    1985-10-07

    The prevention of electrode material erosion by undercutting in the outer electrode shell of igniter electrodes of jet engine ignition systems is prevented by the application of an electrical insulation coating. The coating is applied to the surface of the outer electrode shell which faces the ceramic insulation around the center electrode where erosion patterns are known to occur. The insulation material is selected from electrical insulation substances such as oxides of aluminum, tungsten, magnesium, beryllium or zirconium by choosing a non-porous electrical-insulating substance with thermal-expansion characteristics approximately equalling those of the outer electrode shell. Since a typical outer electrode shell is composed of 446 stainless steel, an optimum choice for the electrical insulation coating is Al/sub 2/O/sub 3/ deposited with a coating thickness of between 5 and 10 mils.

  16. AIR EMISSIONS FROM LASER DRILLING OF PRINTED WIRING BOARD MATERIALS

    EPA Science Inventory

    The paper gives results of a study to characterize gases generated during laser drilling of printed wiring board (PWB) material and identifies the pollutants and generation rates found during the drilling process. Typically found in the missions stream were trace amounts of carbo...

  17. 49 CFR 175.25 - Notification at air passenger facilities of hazardous materials restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Notification at air passenger facilities of hazardous materials restrictions. 175.25 Section 175.25 Transportation Other Regulations Relating to... passenger facilities of hazardous materials restrictions. Each person who engages in for-hire...

  18. Non-Print Instructional Materials for the Air Conditioning and Refrigeration Maintenance Field.

    ERIC Educational Resources Information Center

    Golitko, Raymond L., Ed.; And Others

    This catalog contains a listing of air conditioning/refrigeration maintenance audiovisual training materials from the Houston Community College System library media collection. The material is organized by subject heading. The media titles are listed in alphabetical order by title under each subject heading in the catalog. The citation for each…

  19. Copper oxide nanowires as better performance electrode material for supercapacitor application

    NASA Astrophysics Data System (ADS)

    Yar, A.; Dennis, J. O.; Mohamed, N. M.; Mian, M. U.; Irshad, M. I.; Mumtaz, A.

    2016-11-01

    Supercapacitors are highly attractive energy storage devices which are capable of delivering high power, with fast charging and long cycle life. Carbon based material rely on physical charging with less capacitance while metal oxide store charge by fast redox reaction with increased capacitance. Among metal oxide, copper oxide compounds are widely use in the form of nano and micro structures with no definite control over structure. In this work we utilized the well-controlled structure copper wires, originated from AAO template. Such well controlled structure offer better capacitance values due to easily excess of ions to the surface of wires. Performance of material was check in 3 M of potassium hydroxide (KOH). Specific capacitance (Cs) was calculated by using cyclic voltammetry (CV) and Charge discharge (CDC) test. The capacitance calculate on base on CV at 25 mV/s was 101.37 F/g while CDC showed the capacitance of 90 F/g at 2 A/g.

  20. Ultra-small vanadium nitride quantum dots embedded in porous carbon as high performance electrode materials for capacitive energy storage

    NASA Astrophysics Data System (ADS)

    Yang, Yunlong; Zhao, Lei; Shen, Kuiwen; Liu, Ying; Zhao, Xiaoning; Wu, Yage; Wang, Yanqin; Ran, Fen

    2016-11-01

    Ultra-small vanadium nitride quantum dots embedded in porous carbon (VNQDs/PC) were fabricated by a thermal treatment process of NH4VO3/C3H6N6 under nitrogen atmosphere. The specific capacitance of VNQDs/PC was 1008 mF cm-2 at a current density of 0.004 A cm-2, whereas the VN/carbon hybrid material obtained by a solid-state blending of NH4VO3 and C3H6N6 just exhibited a capacitance of 432 mF cm-2 at the same current density. By mediating the ratio of NH4VO3 and C3H6N6, a maximum specific capacitance of 1124 mF cm-2 was achieved at a current density of 0.002 A cm-2 in aqueous 6 mol/L KOH electrolyte with the potential range from 0 to -1.15 V when it reached 1: 7 (wt./wt.). Additionally, symmetrical supercapacitor fabricated with synthesized VNQDs/PC presented a high specific capacitance of 215 mF cm-2 at 0.002 A cm-2 based on the entire cell, and exhibited a high capacitance retention of 86.6% with current density increased to 5 A g-1. The VNQDs/PC negative electrodes were combined with Ni(OH)2 positive electrodes for the fabrication of hybrid supercapacitors. Remarkably, at a power density of 828.7 W kg-1, the device delivered an ultrahigh energy density of 47.2 Wh kg-1.

  1. Electrical Characteristics, Electrode Sheath and Contamination Layer Behavior of a Meso-Scale Premixed Methane-Air Flame Under AC/DC Electric Fields

    NASA Astrophysics Data System (ADS)

    Chen, Qi; Yan, Limin; Zhang, Hao; Li, Guoxiu

    2016-05-01

    Electrical characteristics of a nozzle-attached meso-scale premixed methane-air flame under low-frequency AC (0-4300 V, 0-500 Hz) and DC (0-3300 V) electric fields were studied. I-V curves were measured under different experimental conditions to estimate the magnitude of the total current 100-102 μA, the electron density 1015-1016 m-3 and further the power dissipation ≤ 0.7 W in the reaction zone. At the same time, the meso-scale premixed flame conductivity 10-4-10-3 Ω-1·m-1 as a function of voltage and frequency was experimentally obtained and was believed to represent a useful order-of magnitude estimate. Moreover, the influence of the collision sheath relating to Debye length (31-98 μm) and the contamination layer of an active electrode on measurements was discussed, based on the combination of simulation and theoretical analysis. As a result, the electrode sheath dimension was evaluated to less than 0.5 mm, which indicated a complex effect of the collision sheath on the current measurements. The surface contamination effect of an active electrode was further analyzed using the SEM imaging method, which showed elements immigration during the contamination layer formation process. supported by National Natural Science Foundation of China (No. 51376021), and the Fundamental Research Fund for Major Universities (No. 2013JBM079)

  2. Preparation of energy storage material derived from a used cigarette filter for a supercapacitor electrode.

    PubMed

    Lee, Minzae; Kim, Gil-Pyo; Don Song, Hyeon; Park, Soomin; Yi, Jongheop

    2014-08-29

    We report on a one-step method for preparing nitrogen doped (N-doped) meso-/microporous hybrid carbon material (NCF) via the heat treatment of used cigarette filters under a nitrogen-containing atmosphere. The used cigarette filter, which is mostly composed of cellulose acetate fibers, can be transformed into a porous carbon material that contains both the mesopores and micropores spontaneously. The unique self-developed pore structure allowed a favorable pathway for electrolyte permeation and contact probability, resulting in the extended rate capability for the supercapacitor. The NCF exhibited a better rate capability and higher specific capacitance (153.8 F g(-1)) compared to that of conventional activated carbon (125.0 F g(-1)) at 1 A g(-1). These findings indicate that the synergistic combination of well-developed meso-/micropores, an enlarged surface area and pseudocapacitive behavior leads to the desired supercapacitive performance. The prepared carbon material is capable of reproducing its electrochemical performance during the 6000 cycles required for charge and discharge measurements.

  3. Preparation of energy storage material derived from a used cigarette filter for a supercapacitor electrode

    NASA Astrophysics Data System (ADS)

    Lee, Minzae; Kim, Gil-Pyo; Song, Hyeon Don; Park, Soomin; Yi, Jongheop

    2014-08-01

    We report on a one-step method for preparing nitrogen doped (N-doped) meso-/microporous hybrid carbon material (NCF) via the heat treatment of used cigarette filters under a nitrogen-containing atmosphere. The used cigarette filter, which is mostly composed of cellulose acetate fibers, can be transformed into a porous carbon material that contains both the mesopores and micropores spontaneously. The unique self-developed pore structure allowed a favorable pathway for electrolyte permeation and contact probability, resulting in the extended rate capability for the supercapacitor. The NCF exhibited a better rate capability and higher specific capacitance (153.8 F g-1) compared to that of conventional activated carbon (125.0 F g-1) at 1 A g-1. These findings indicate that the synergistic combination of well-developed meso-/micropores, an enlarged surface area and pseudocapacitive behavior leads to the desired supercapacitive performance. The prepared carbon material is capable of reproducing its electrochemical performance during the 6000 cycles required for charge and discharge measurements.

  4. Preparation of Fiber Based Binder Materials to Enhance the Gas Adsorption Efficiency of Carbon Air Filter.

    PubMed

    Lim, Tae Hwan; Choi, Jeong Rak; Lim, Dae Young; Lee, So Hee; Yeo, Sang Young

    2015-10-01

    Fiber binder adapted carbon air filter is prepared to increase gas adsorption efficiency and environmental stability. The filter prevents harmful gases, as well as particle dusts in the air from entering the body when a human inhales. The basic structure of carbon air filter is composed of spunbond/meltblown/activated carbon/bottom substrate. Activated carbons and meltblown layer are adapted to increase gas adsorption and dust filtration efficiency, respectively. Liquid type adhesive is used in the conventional carbon air filter as a binder material between activated carbons and other layers. However, it is thought that the liquid binder is not an ideal material with respect to its bonding strength and liquid flow behavior that reduce gas adsorption efficiency. To overcome these disadvantages, fiber type binder is introduced in our study. It is confirmed that fiber type binder adapted air filter media show higher strip strength, and their gas adsorption efficiencies are measured over 42% during 60 sec. These values are higher than those of conventional filter. Although the differential pressure of fiber binder adapted air filter is relatively high compared to the conventional one, short fibers have a good potential as a binder materials of activated carbon based air filter.

  5. A difference in using atomic layer deposition or physical vapour deposition TiN as electrode material in metal-insulator-metal and metal-insulator-silicon capacitors.

    PubMed

    Groenland, A W; Wolters, R A M; Kovalgin, A Y; Schmitz, J

    2011-09-01

    In this work, metal-insulator-metal (MIM) and metal-insulator-silicon (MIS) capacitors are studied using titanium nitride (TiN) as the electrode material. The effect of structural defects on the electrical properties on MIS and MIM capacitors is studied for various electrode configurations. In the MIM capacitors the bottom electrode is a patterned 100 nm TiN layer (called BE type 1), deposited via sputtering, while MIS capacitors have a flat bottom electrode (called BE type 2-silicon substrate). A high quality 50-100 nm thick SiO2 layer, made by inductively-coupled plasma CVD at 150 degrees C, is deposited as a dielectric on top of both types of bottom electrodes. BE type 1 (MIM) capacitors have a varying from low to high concentration of structural defects in the SiO2 layer. BE type 2 (MIS) capacitors have a low concentration of structural defects and are used as a reference. Two sets of each capacitor design are fabricated with the TiN top electrode deposited either via physical vapour deposition (PVD, i.e., sputtering) or atomic layer deposition (ALD). The MIM and MIS capacitors are electrically characterized in terms of the leakage current at an electric field of 0.1 MV/cm (I leak) and for different structural defect concentrations. It is shown that the structural defects only show up in the electrical characteristics of BE type 1 capacitors with an ALD TiN-based top electrode. This is due to the excellent step coverage of the ALD process. This work clearly demonstrates the sensitivity to process-induced structural defects, when ALD is used as a step in process integration of conductors on insulation materials.

  6. Nanostructured Electrode Materials Derived from Metal-Organic Framework Xerogels for High-Energy-Density Asymmetric Supercapacitor.

    PubMed

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

    2016-01-27

    This work successfully demonstrates metal-organic framework (MOF) derived strategy to prepare nanoporous carbon (NPC) with or without Fe3O4/Fe nanoparticles by the optimization of calcination temperature as highly active electrode materials for asymmetric supercapacitors (ASC). The nanostructured Fe3O4/Fe/C hybrid shows high specific capacitance of 600 F/g at a current density of 1 A/g and excellent capacitance retention up to 500 F/g at 8 A/g. Furthermore, hierarchically NPC with high surface area also obtained from MOF gels displays excellent electrochemical performance of 272 F/g at 2 mV/s. Considering practical applications, aqueous ASC (aASC) was also assembled, which shows high energy density of 17.496 Wh/kg at the power density of 388.8 W/kg. The high energy density and excellent capacity retention of the developed materials show great promise for the practical utilization of these energy storage devices.

  7. Advanced cathode materials for polymer electrolyte fuel cells based on pt/ metal oxides: from model electrodes to catalyst systems.

    PubMed

    Fabbri, Emiliana; Pătru, Alexandra; Rabis, Annett; Kötz, Rüdiger; Schmidt, Thomas J

    2014-01-01

    The development of stable catalyst systems for application at the cathode side of polymer electrolyte fuel cells (PEFCs) requires the substitution of the state-of-the-art carbon supports with materials showing high corrosion resistance in a strongly oxidizing environment. Metal oxides in their highest oxidation state can represent viable support materials for the next generation PEFC cathodes. In the present work a multilevel approach has been adopted to investigate the kinetics and the activity of Pt nanoparticles supported on SnO2-based metal oxides. Particularly, model electrodes made of SnO2 thin films supporting Pt nanoparticles, and porous catalyst systems made of Pt nanoparticles supported on Sb-doped SnO2 high surface area powders have been investigated. The present results indicate that SnO2-based supports do not modify the oxygen reduction reaction mechanism on the Pt nanoparticle surface, but rather lead to catalysts with enhanced specific activity compared to Pt/carbon systems. Different reasons for the enhancement in the specific activity are considered and discussed.

  8. Large-scale production of nanographene sheets with a controlled mesoporous architecture as high-performance electrochemical electrode materials.

    PubMed

    Zhang, Haitao; Zhang, Xiong; Sun, Xianzhong; Zhang, Dacheng; Lin, He; Wang, Changhui; Wang, Hongjin; Ma, Yanwei

    2013-06-01

    Graphene is considered as a rising-star material because of its unique properties and it is a promising material for applications in many fields. In recent years, experiments on graphene fabricated by using versatile methods have shed light on the crucial problem of aggregation and restacking, which is induced by strong π-π stacking and van der Waals forces, but preparation methods for real-world applications are still a great challenge. Here we report a facile, rapid, and environmentally friendly process, the burn-quench method, that allows large-scale and controlled synthesis of ordered mesoporous nanographene with 1-5 layers, which has a high surface area and electric conductivity. Electrodes composed of nanographene with a mesoporous architecture used both in electrochemical capacitors and lithium-ion batteries have a high specific capacitance, rate capability, energy density, and cyclic stability. Our results represent an important step toward large-scale graphene synthesis based on this new burn-quench method for applications in high-performance electrochemical energy storage devices.

  9. Copper-Filled Through-Hole Electrode of a ZnS Window Material for Sealing a Thermal Infrared Sensor

    NASA Astrophysics Data System (ADS)

    Fukumoto, Takafumi; Okamoto, Naoki; Ohta, Yoshimi; Fukuyama, Yasuhiro; Hirota, Masaki; Kondo, Kazuo

    The through-hole electrode for the wafer level package (WLP) was formed with the aim of lowering the cost of infrared sensors. It has been difficult to plate a ZnS substrate for use as the window material of WLPs because of low adhesion. However, through-hole filling was successfully accomplished in this work by applying a newly developed method of direct nonelectrolyte plating. Concretely, a blast cleaning process was performed on a ZnS substrate of 1 mm thickness. Then, a through-hole with both sides tapered was formed with an aspect ratio of 7. A compound process of Cu substitution plating and Ni nonelectrolyte plating was applied to the through-hole, forming a uniform plating film with high adhesion in the hole. Finally, the through-hole was completely filled by Cu electroplating. A He leak test confirmed that the sample had high sealing properties, with a measured leak rate of 1.0 × 10-10 Pa·m3/sec or less. The results showed that a ZnS substrate can be used effectively for IR window material, making it possible to reduce the cost of infrared cameras.

  10. Methods for and products of processing nanostructure nitride, carbonitride and oxycarbonitride electrode power materials by utilizing sol gel technology for supercapacitor applications

    DOEpatents

    Huang, Yuhong; Wei, Oiang; Chu, Chung-tse; Zheng, Haixing

    2001-01-01

    Metal nitride, carbonitride, and oxycarbonitride powder with high surface area (up to 150 m.sup.2 /g) is prepared by using sol-gel process. The metal organic precursor, alkoxides or amides, is synthesized firstly. The metal organic precursor is modified by using unhydrolyzable organic ligands or templates. A wet gel is formed then by hydrolysis and condensation process. The solvent in the wet gel is then be removed supercritically to form porous amorphous hydroxide. This porous hydroxide materials is sintered to 725.degree. C. under the ammonia flow and porous nitride powder is formed. The other way to obtain high surface area nitride, carbonitride, and oxycarbonitride powder is to pyrolyze polymerized templated metal amides aerogel in an inert atmosphere. The electrochemical capacitors are prepared by using sol-gel prepared nitride, carbonitride, and oxycarbonitride powder. Two methods are used to assemble the capacitors. Electrode is formed either by pressing the mixture of nitride powder and binder to a foil, or by depositing electrode coating onto metal current collector. The binder or coating is converted into a continuous network of electrode material after thermal treatment to provide enhanced energy and power density. Liquid electrolyte is soaked into porous electrode. The electrochemical capacitor assembly further has a porous separator layer between two electrodes/electrolyte and forming a unit cell.

  11. Left Handed Materials Research for Air Force Applications

    DTIC Science & Technology

    2011-08-31

    a high Tc superconducting material, such as YBCO , with mixed results. 3. After optimizing the key figures of merit of our single frequency (~3...amplification, our microwave spectrometer has the potential to detect superconducting grains of YBCO weighing as little as 1 microgram, or nanometer...thickness YBCO superconducting films with mass as low as 10 nanograms. We designed and built our system to operate at temperatures between 4K and 400K. A

  12. Tungsten - Tungsten Trioxide Electrodes for the Long-term Monitoring of Corrosion Processes in Highly Alkaline Media and Concrete-based Materials.

    PubMed

    Kolar, Mitja; Doliška, Aleš; Svegl, Franc; Kalcher, Kurt

    2010-12-01

    The determination of pH in highly alkaline solutions and concrete materials is extremely important for monitoring or predicting the corrosion processes of reinforced concrete structures and to follow the hydration process of Portland cement, fly-ash, micro silica and other materials used in concrete manufacturing. The corrosion of reinforced concrete structures and the hydration of pozzolanic materials are long-term processes, which means, that appropriate durable, and resilient pH electrodes are needed, for direct implantation regarding solid concrete bodies. The purpose of this work was to characterise the potentiometric and surface properties of tungsten electrodes after exposure to extreme alkaline solutions. The tungsten wire surface was activated at 800 °C for 30 min within an oxygen flow. The formation of homogenous and compact multiple layers of WO3 crystals was observed using X-ray diffraction and scanning electron microscopy. X-ray diffraction of those tungsten electrodes exposed to saturated calcium hydroxide solution or the pore-water of cement-based materials during 10 months, indicated partly dissolved WO3. Two new compounds appeared on the electrodes surfaces; pure tungsten and CaWO4. The presence of tungsten was affecting any potentiometric response in acidic pH region (2-5) but in pH 5-12 region the response still remained linear with a slope of 42 ± 2 mV/pH unit. The W/WO3 electrode was suitable for the long-term monitoring of corrosion processes in concrete-based materials according to the pH changes as it has stable and repeatable responses to alkaline solutions (pH > 12). All the tested interferring ions had no significant influence on electrode potential. The W/WO3 electrode is simple, robust, inexpensive, and temperature resistant and can be applied in potentiometric titrations as well as in batch and flow-injection analysis. The prepared electrode is a highly promising pH sensor for the monitoring of pH changes in highly alkaline capillary

  13. Optimization of graphene oxide synthesis parameters for improving their after-reduction material performance in functional electrodes

    NASA Astrophysics Data System (ADS)

    Kim, Yong Jae; Kahng, Yung Ho; Hwang, Yun-Hwa; Lee, Sun Min; Lee, Sung-Youp; Lee, Hyeong-Rag; Lee, Seoung Ho; Nam, Sang Hoon; Kim, Won Bae; Lee, Kwanghee

    2016-10-01

    Optimization of the parameters of a modified Hummers’ method for graphene oxide (GO) synthesis is conducted in this study. Focusing specifically on their applications for transparent electrodes and supercapacitor electrodes, the properties of the thin layers and electrodes prepared from GO and thermally reduced GO (RGO) were investigated using UV-visible spectroscopy, Hall measurements, atomic force microscopy, x-ray photoelectron spectroscopy, and cyclic voltammetry. The obtained results reveal that promoting the oxidation of graphite, either by increasing the acid reaction time or the oxidant dosage, improves the morphological and optoelectrical properties of the resulting graphene thin layers for transparent electrode applications. On the other hand, improving the synthesis parameters was not necessary for obtaining high-quality supercapacitor electrodes. Adopting thermal reduction conditions (involving thermal shocking) was as effective as using optimized synthetic conditions in increasing the gravimetric specific capacitance for the supercapacitor electrodes prepared using RGO.

  14. Smart plastic antibody material (SPAM) tailored on disposable screen printed electrodes for protein recognition: application to myoglobin detection.

    PubMed

    Moreira, Felismina T C; Sharma, Sanjiv; Dutra, Rosa A F; Noronha, João P C; Cass, Anthony E G; Sales, M Goreti F

    2013-07-15

    This work introduces two major changes to the conventional protocol for designing plastic antibodies: (i) the imprinted sites were created with charged monomers while the surrounding environment was tailored using neutral material; and (ii) the protein was removed from its imprinted site by means of a protease, aiming at preserving the polymeric network of the plastic antibody. To our knowledge, these approaches were never presented before and the resulting material was named here as smart plastic antibody material (SPAM). As proof of concept, SPAM was tailored on top of disposable gold-screen printed electrodes (Au-SPE), following a bottom-up approach, for targeting myoglobin (Myo) in a point-of-care context. The existence of imprinted sites was checked by comparing a SPAM modified surface to a negative control, consisting of similar material where the template was omitted from the procedure and called non-imprinted materials (NIMs). All stages of the creation of the SPAM and NIM on the Au layer were followed by both electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). AFM imaging was also performed to characterize the topography of the surface. There are two major reasons supporting the fact that plastic antibodies were effectively designed by the above approach: (i) they were visualized for the first time by AFM, being present only in the SPAM network; and (ii) only the SPAM material was able to rebind to the target protein and produce a linear electrical response against EIS and square wave voltammetry (SWV) assays, with NIMs showing a similar-to-random behavior. The SPAM/Au-SPE devices displayed linear responses to Myo in EIS and SWV assays down to 3.5 μg/mL and 0.58 μg/mL, respectively, with detection limits of 1.5 and 0.28 μg/mL. SPAM materials also showed negligible interference from troponin T (TnT), bovine serum albumin (BSA) and urea under SWV assays, showing promising results for point-of-care applications when applied to spiked

  15. Interfacial behaviours between lithium ion conductors and electrode materials in various battery systems

    SciTech Connect

    Wu, Bingbin; Wang, Shanyu; Evans IV, Willie J.; Deng, Daniel Z.; Yang, Jihui; Xiao, Jie

    2016-01-01

    In recent years room temperature Li+ ion conductors have been intensively revisited in order to develop safe lithium ion (Li-ion) batteries and beyond that can be deployed in the electrical vehicles. Through careful modification on materials synthesis, promising solid Li+ conductors with high ionic conductivity, competitve with liquid electrolytes, have been demonstrated. However, the integration of those highly conductive solid electrolytes into the whole system is still very challenging mainly due to the high impedance existing in the different interfaces throughout the entire battery structure. Herein , this review paper focuses on the overview of the interfacial behaviors between Li+ conductors and cathode/anode materials. The origin, evolution and potential solutions to reuce these interfacial impedances are reviewed for various battery systems spanning from Li-ion, lithium sulfur (Li-S), lithium oxygen (Li-O2) batteries to lithium metal protection. The predicted gravimetric and volumetric energy densities at different scenarios are also discussed along with the prospectives for further development of solid state batteries.

  16. Monitor of the concentration of particles of dense radioactive materials in a stream of air

    DOEpatents

    Yule, Thomas J.

    1979-01-01

    A monitor of the concentration of particles of radioactive materials such as plutonium oxide in diameters as small as 1/2 micron includes in combination a first stage comprising a plurality of virtual impactors, a second stage comprising a further plurality of virtual impactors, a collector for concentrating particulate material, a radiation detector disposed near the collector to respond to radiation from collected material and means for moving a stream of air, possibly containing particulate contaminants, through the apparatus.

  17. Moving Graphitic Carbon Nitride from Electrocatalysis and Photocatalysis to a Potential Electrode Material for Photoelectric Devices.

    PubMed

    Xu, Jingsan; Antonietti, Markus; Shalom, Menny

    2016-09-20

    Carbon nitride (g-CN) has attracted significant interest in the last years as a robust, low-cost alternative to metal-based materials in different fields due to its low price, environmentally benign character, simple synthesis and tunable properties. In particular, g-CN demonstrates promising activity in energy-related applications such as photo and heterogeneous catalysis, batteries and electrolysis. However, while g-CN is already well-established as a photocatalyst, its utilization in (opto)electronic devices is still at an early stage. This Focus Review concentrates on the utilization of g-CN in solar and photoelectrochemical cells, electrolyzers and light emitting diode alongside the recap of new synthetic approaches. This review is expected to provide useful insights into the design and fabrication of g-CN based photoelectronic devices as well as g-CN working principles, including the main challenges toward its integration in optoelectronic devices.

  18. Superior supercapacitor electrode material from hydrazine hydrate modified porous polyacrylonitrile fiber

    NASA Astrophysics Data System (ADS)

    Li, Ying; Lu, Chunxiang; Wang, Junzhong; Yan, Hua; Zhang, Shouchun

    2016-03-01

    A hierarchical porous carbon fiber with high nitrogen doping was fabricated for high-performance supercapacitor. For the purpose of high nitrogen retention, the porous polyacrylonitrile fiber was treated by hydrazine hydrate, and then underwent pre-oxidation, carbonization, and activation in sequence. The resulted material exhibited high nitrogen content of 7.82 at.%, large specific surface area of 1963.3m2 g-1, total pore volume of 1.523cm3 g-1, and the pores with size range of 1-4nm were account for 49.1%. Due to these features, the high reversible capacitance of 415F g-1 and the good performance in heavy load discharge were obtained. In addition, the amazing cyclability was observed after 10,000 circles without capacitance fading.

  19. Work function determination of promising electrode materials for thermionic energy converters

    NASA Technical Reports Server (NTRS)

    Jacobson, D.; Storms, E.; Skaggs, B.; Kouts, T.; Jaskie, J.; Manda, M.

    1976-01-01

    The work function determinations of candidate materials for low temperature (1400 K) thermionics through vacuum emission tests are discussed. Two systems, a vacuum emission test vehicle and a thermionic emission microscope are used for emission measurements. Some nickel and cobalt based super alloys were preliminarily examined. High temperature physical properties and corrosion behavior of some super alloy candidates are presented. The corrosion behavior of sodium is of particular interest since topping cycles might use sodium heat transfer loops. A Marchuk tube was designed for plasma discharge studies with the carbide and possibly some super alloy samples. A series of metal carbides and other alloys were fabricated and tested in a special high temperature mass spectrometer. This information coupled with work function determinations was evaluated in an attempt to learn how electron bonding occurs in transition alloys.

  20. Evaluation of air permeability in layered unsaturated materials.

    PubMed

    Switzer, Christine; Kosson, David S

    2007-03-20

    Field estimation of air permeability is important in the design and operation of soil-vapor extraction systems. Previous models have examined airflow in homogenous soils, incorporating leakage through a low-permeability cap either as a correction to the airflow equation or as a boundary condition. The dual leakage model solution developed here improves upon the previous efforts by adding a leaky lower boundary condition, allowing for the examination of airflow in heterogeneous layered soils. The dual leakage model is applied to the evaluation of pump tests at a pilot soil-vapor extraction system at the Savannah River Site in South Carolina. A thick, low-permeability, stiff clay layer divides the stratigraphy at the site into two units for evaluation. A modified version of the previous model, using the water table as the impermeable lower boundary, is used to evaluate the permeability of the low-permeability stiff clay layer (3.2 x 10(-10) cm(2)) and permeable sand (7.2 x 10(-7) cm(2)) beneath it. The stiff clay permeability estimate is used in the evaluation of the shallow unit. Permeability estimates of the shallow sand (3.8 x 10(-7) cm(2)) and kaolin cap (1.5 x 10(-9)cm(2)) were obtained with the dual leakage model. The shallow unit was evaluated using the previous model for comparison. The effects of anisotropy were investigated with a series of model simulations based on the shallow unit solution. The anisotropy sensitivity analysis suggests that increased anisotropy ratio or decreased axial permeability has a significant impact on the velocity profile at the lower boundary, especially at high values of the anisotropy ratio. This result may increase estimates of SVE removal rates for contaminants located at the interface of the lower boundary, typical of chlorinated solvent contamination.

  1. Creep Performance of Oxide Ceramic Fiber Materials at Elevated Temperature in Air and in Steam

    DTIC Science & Technology

    2011-03-24

    performance in harsh environments are prime candidates for such applications . Oxide ceramic materials have been used as constituents in CMCs...since 1965, when the United States Air Force led the effort to bring high performance fiber composites to practical applications [26]. Today...bulk polycrystalline alumina cubes were performed in air and steam at 1100 and 1300°C. Both the bulk alumina and YAG specimens were processed in two

  2. A microwave synthesis of mesoporous NiCo2O4 nanosheets as electrode materials for lithium-ion batteries and supercapacitors.

    PubMed

    Mondal, Anjon Kumar; Su, Dawei; Chen, Shuangqiang; Kretschmer, Katja; Xie, Xiuqiang; Ahn, Hyo-Jun; Wang, Guoxiu

    2015-01-12

    A facile microwave method was employed to synthesize NiCo2 O4 nanosheets as electrode materials for lithium-ion batteries and supercapacitors. The structure and morphology of the materials were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Teller methods. Owing to the porous nanosheet structure, the NiCo2 O4 electrodes exhibited a high reversible capacity of 891 mA h g(-1) at a current density of 100 mA g(-1) , good rate capability and stable cycling performance. When used as electrode materials for supercapacitors, NiCo2 O4 nanosheets demonstrated a specific capacitance of 400 F g(-1) at a current density of 20 A g(-1) and superior cycling stability over 5000 cycles. The excellent electrochemical performance could be ascribed to the thin porous structure of the nanosheets, which provides a high specific surface area to increase the electrode-electrolyte contact area and facilitate rapid ion transport.

  3. End-of-life nickel-cadmium accumulators: characterization of electrode materials and industrial Black Mass.

    PubMed

    Hazotte, Claire; Leclerc, Nathalie; Diliberto, Sébastien; Meux, Eric; Lapicque, Francois

    2015-01-01

    The aim of this paper is the characterization of spent NiCd batteries and the characterization of an industrial Black Mass obtained after crushing spent NiCd batteries and physical separation in a treatment plant. The characterization was first performed with five cylindrical NiCd batteries which were manually dismantled. Their characterization includes mass balance of the components, active powders elemental analysis and phase identification by X-ray powder diffraction. Chemical speciation of the two metals was also investigated. For cadmium, speciation was previously developed on solid synthetic samples. In a spent battery, the active powders correspond to about 43% of the battery weight. The other components are the separator and polymeric pieces (5%), the support plates (25%) and the carbon steel external case (27%). The sequential procedure shows that the nickel in the positive powders from the dismantled Ni-Cd batteries is distributed between Ni0 (39.7%), Ni(OH)2 (58.5%) and NiOOH (1.8%). Cadmium in the negative powder is about 99.9% as the Cd(OH)2 form with 0.1% of metal cadmium. In the industrial Black Mass, the distribution of cadmium is the same, whereas the distribution of nickel is Ni0 (46.9%), Ni(OH)2 (43.2%) and NiOOH (9.9%). This material contains also 1.8% cobalt and approx. 1% iron.

  4. Effect of mesocelluar carbon foam electrode material on performance of vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Jeong, Sanghyun; An, Sunhyung; Jeong, Jooyoung; Lee, Jinwoo; Kwon, Yongchai

    2015-03-01

    Languid reaction rate of VO2+/VO2+ redox couple is a problem to solve for improving performance of vanadium redox flow battery (VRFB). To facilitate the slow reaction materials including large pore sized mesocellular carbon foam (MSU-F-C and Pt/MSU-F-C) are used as new catalyst. Their catalytic activity and reaction reversibility are estimated and compared with other catalysts, while cycle tests of charge-discharge and polarization curve tests are implemented to evaluate energy efficiency (EE) and maximum power density (MPD). Their crystal structure, specific surface area and catalyst morphology are measured by XRD, BET and TEM. The new catalysts indicate high peak current ratio, small peak potential difference and high electron transfer rate constant, proving that their catalytic activity and reaction reversibility are superior. Regarding the charge-discharge and polarization curve tests, the VRFB single cells including new catalysts show high EE as well as low overpotential and internal resistance and high MPD. Such excellent results are due to mostly unique characteristics of MSU-F-C having large interconnected mesopores, high surface area and large contents of hydroxyl groups that serve as active sites for VO2+/VO2+ redox reaction and platinums (Pts) supporting the MSU-F-C. Indeed, employment of the catalysts including MSU-F-C leads to enhancement in performance of VRFB by facilitating the slow VO2+/VO2+ redox reaction.

  5. Development of a Flexible Non-Metal Electrode for Cell Stimulation and Recording

    PubMed Central

    Gong, Cihun-Siyong Alex; Syu, Wun-Jia; Lei, Kin Fong; Hwang, Yih-Shiou

    2016-01-01

    This study presents a method of producing flexible electrodes for potentially simultaneously stimulating and measuring cellular signals in retinal cells. Currently, most multi-electrode applications rely primarily on etching, but the metals involved have a certain degree of brittleness, leaving them prone to cracking under prolonged pressure. This study proposes using silver chloride ink as a conductive metal, and polydimethysiloxane (PDMS) as the substrate to provide electrodes with an increased degree of flexibility to allow them to bend. This structure is divided into the electrode layer made of PDMS and silver chloride ink, and a PDMS film coating layer. PDMS can be mixed in different proportions to modify the degree of rigidity. The proposed method involved three steps. The first segment entailed the manufacturing of the electrode, using silver chloride ink as the conductive material, and using computer software to define the electrode size and micro-engraving mechanisms to produce the electrode pattern. The resulting uniform PDMS pattern was then baked onto the model, and the flow channel was filled with the conductive material before air drying to produce the required electrode. In the second stage, we tested the electrode, using an impedance analyzer to measure electrode cyclic voltammetry and impedance. In the third phase, mechanical and biocompatibility tests were conducted to determine electrode properties. This study aims to produce a flexible, non-metallic sensing electrode which fits snugly for use in a range of measurement applications. PMID:27690049

  6. Capacitive de-ionization electrode

    DOEpatents

    Daily, III, William D.

    2013-03-19

    An electrode "cell" for use in a capacitive deionization (CDI) reactor consists of the electrode support structure, a non-reactive conductive material, the electrode accompaniment or substrate and a flow through screen/separator. These "layers" are repeated and the electrodes are sealed together with gaskets between two end plates to create stacked sets of alternating anode and cathode electrodes in the CDI reactor.

  7. Concentrations and decay rates of ozone in indoor air in dependence on building and surface materials.

    PubMed

    Moriske, H J; Ebert, G; Konieczny, L; Menk, G; Schöndube, M

    1998-08-01

    The decay of ozone in indoor air was measured in a closed chamber after contact with different building materials and residential surfaces. The tested materials were: vinyl wall paper, woodchip paper, plywood, latex paint, fitted carpet, and plaster. In the summer of 1996, the entry of ozone from ambient air into indoor air during ventilation and the ozone decay in indoor air, after windows had been closed again, were studied. Measurements were done in a residential house on the outskirts of Berlin. The following results were gained: the chamber measurements showed a decay of ozone after contact with most of the materials put inside the chamber. Higher decay rates have been obtained for wall papers, plywood, fitted carpet and plaster. As described in the literature, ozone is able to react with olefines inside the materials and is able to form formaldehyde and other components. This formation of formaldehyde could also be confirmed in our investigations. Thus, in most cases, the formaldehyde concentrations were lower than the German guideline value of 0.1 ppm. The formation of formaldehyde could be prevented when a special wall paper that was coated with activated carbon was used. In the house, a complete ozone diffusion into indoor air took place during ventilation within 30 min. After closing the windows, the ozone concentrations decreased to the basic level before ventilation within 60-90 min.

  8. Surface-modified Mg{sub 2}Ni-type negative electrode materials for Ni-MH battery

    SciTech Connect

    Cui, N.; Luan, B.; Bradhurst, D.; Liu, H.K.; Dou, S.X.

    1997-12-01

    In order to further improve the electrode performance of Mg{sub 1.9}Y{sub 0.1}Ni{sub 0.9}Al{sub 0.1} alloy at ambient temperature, its surface was modified by an ultrasound pretreatment in the alkaline solution and microencapsulation with Ni-P coating. The effects of various surface modifications on the microstructure and electrochemical performance of the alloy electrodes were investigated and compared in this paper. It was found that the modification with ultrasound pretreatment significantly improved the electrocatalytic activity of the negative electrode and then reduced the overpotential of charging/discharging, resulting in a remarkable increase of electrode capacity and high-rate discharge capability but having little influence on the cycle life. However, the electrode fabricated from the microencapsulated alloy powder showed a higher discharge capacity, better high-rate discharge capability and longer cycle life as well.

  9. Humid air corrosion of YMP waste package candidate material

    SciTech Connect

    Gdowski, G.E.

    1998-01-01

    The Yucca Mountain Site Characterization Project is evaluating candidate materials for high level nuclear waste containers (Waste Packages) for a potential deep geologic repository at Yucca Mountain, Nevada. The potential repository is located above the water table in the unsaturated zone. The rock contains nominally 10% by volume water and gas pressure in the emplacement drifts of the repository is expected to remain near the ambient atmospheric pressure. The heat generated by the radioactive decay of the waste will raise the temperature of the waste packages and the surrounding rock. Waste Package temperatures above the ambient boiling point of water are anticipated for the waste emplacement scenarios. Because the repository emplacement drifts are expected to remain at the ambient atmospheric pressure, the maximum relative humidity obtainable decreases above the boiling point of water. Temperatures of the Waste Packages and the surrounding rock are expected to reach maximum temperature within 100`s of years and then gradually decrease with time. Episodic liquid water contact with the WPs is also expected; this will result in the deposition of salts and mineral scale.

  10. Negative electrode composition

    DOEpatents

    Kaun, Thomas D.; Chilenskas, Albert A.

    1982-01-01

    A secondary electrochemical cell and a negative electrode composition for use therewith comprising a positive electrode containing an active material of a chalcogen or a transiton metal chalcogenide, a negative electrode containing a lithium-aluminum alloy and an amount of a ternary alloy sufficient to provide at least about 5 percent overcharge capacity relative to a negative electrode solely of the lithium-aluminum alloy, the ternary alloy comprising lithium, aluminum, and iron or cobalt, and an electrolyte containing lithium ions in contact with both of the positive and the negative electrodes. The ternary alloy is present in the electrode in the range of from about 5 percent to about 50 percent by weight of the electrode composition and may include lithium-aluminum-nickel alloy in combination with either the ternary iron or cobalt alloys. A plurality of series connected cells having overcharge capacity can be equalized on the discharge side without expensive electrical equipment.

  11. Effect of the top electrode materials on the resistive switching characteristics of TiO2 thin film

    NASA Astrophysics Data System (ADS)

    Oh, Sang Chul; Jung, Ho Yong; Lee, Heon

    2011-06-01

    Various metals, such as Pt, stainless steel (SUS), Al, Ni, and Ti, were used as a top electrode (TE) to evaluate the dependency of the resistive switching characteristics on the TE of the metal/TiO2/Pt structure. The variation of the chemical composition of TiO2 in the metal/TiO2/Pt structure before and after switching was examined to identify the factors affecting the resistive switching characteristics of the samples with various TE materials. In the case of TE/TiO2/Pt structures showing unstable resistive switching behavior, e.g., those with the Al, Ni, and Ti TEs, secondary ion mass spectrometry revealed an increase in the oxygen concentration at the interface area between the TE metal and TiO2. This suggests that the oxidation reaction at the interface between the TE metal and TiO2 might cause the TE/TiO2/Pt structure to exhibit unstable resistive switching characteristics. According to these results, the oxidation reaction at the interface between the metal TE and TiO2 thin film is a primary factor affecting the resistive switching characteristics of TiO2-based Resistive Random Access Memory devices.

  12. Hybrids of NiCo2O4 nanorods and nanobundles with graphene as promising electrode materials for supercapacitors.

    PubMed

    Wang, Zhuo; Zhang, Xin; Zhang, Zhongshen; Qiao, Nanli; Li, Yang; Hao, Zhengping

    2015-12-15

    High dispersion of NiCo2O4 nanorods and porous NiCo2O4 nanobundles decorated on RGO have been synthesized by a facile hydrothermal method, followed by calcination in one step. By adjusting the starting metal sources to realize the synthesis of different morphologies of NiCo2O4. The morphology and the microstructure of the as-prepared composites were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and transmission electron microscope (TEM) techniques. Among them, the porous RGO/NiCo2O4 nanobundles gives a higher specific capacitance of 1278F/g at 1A/g and 719F/g at 20A/g, showing a remarkable rate capability. The excellent electrochemical performances could ascribed to the unique structural feature with higher surface area. It could be anticipated that the synthesized electrode material will gain promising applications in supercapacitors and other devices because of their outstanding characteristics of controllable capacitance and facilely synthesized.

  13. Hierarchical composites of polyaniline-graphene nanoribbons-carbon nanotubes as electrode materials in all-solid-state supercapacitors.

    PubMed

    Liu, Mingkai; Miao, Yue-E; Zhang, Chao; Tjiu, Weng Weei; Yang, Zhibin; Peng, Huisheng; Liu, Tianxi

    2013-08-21

    A three dimensional (3D) polyaniline (PANI)-graphene nanoribbon (GNR)-carbon nanotube (CNT) composite, PANI-GNR-CNT, has been prepared via in situ polymerization of an aniline monomer on the surface of a GNR-CNT hybrid. Here, the 3D GNR-CNT hybrid has been conveniently prepared by partially unzipping the pristine multi-walled CNTs, while the residual CNTs act as "bridges" connecting different GNRs. The morphology and structure of the resulting hybrid materials have been characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy and X-ray diffraction (XRD). Electrochemical tests reveal that the hierarchical PANI-GNR-CNT composite based on the two-electrode cell possesses much higher specific capacitance (890 F g(-1)) than the GNR-CNT hybrid (195 F g(-1)) and neat PANI (283 F g(-1)) at a discharge current density of 0.5 A g(-1). At the same time, the PANI-GNR-CNT composite displays good cycling stability with a retention ratio of 89% after 1000 cycles, suggesting that this novel PANI-GNR-CNT composite is a promising candidate for energy storage applications.

  14. Magnesium substitution to improve the electrochemical performance of layered Li2MnO3 positive-electrode material

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Xiong, Lilong; Xu, Youlong; Xiao, Xiang; Wang, Jisheng; Ren, Zaihuang

    2016-10-01

    Li2MnO3 has received lots of attention due to its large theoretical capacity. However, its application is obstructed by low practical capacity and poor cycling stability. Here, a new tactic of magnesium substitution for partial lithium to improve the electrochemical performance of Li2MnO3 by a traditional solid state reaction is presented. Sample with only 1% magnesium content delivers a large initial discharge capacity of 307.5 mAh g-1 which is much superior than the 241.9 mAh g-1 of pristine Li2MnO3. The cycling performance also get improved that the capacity retention is 84.5% for Li1.98Mg0.01MnO3 but only 77.7% for pristine counterpart after 30 cycles at 0.1 C. Moreover, the effective suppression of voltage decay has been achieved because of improved kinetic properties and leads to a tremendous progress in the energy density which is as much as 944 Wh kg-1 for Li1.98Mg0.01MnO3 compared with 747.1 Wh kg-1 of Li2MnO3. These achievements attained by Mg-doping make Li2MnO3 a promising positive-electrode material for the next generation of lithium ion batteries.

  15. Effects of activated carbon characteristics on the electrosorption capacity of titanium dioxide/activated carbon composite electrode materials prepared by a microwave-assisted ionothermal synthesis method.

    PubMed

    Liu, Po-I; Chung, Li-Ching; Ho, Chia-Hua; Shao, Hsin; Liang, Teh-Ming; Horng, Ren-Yang; Chang, Min-Chao; Ma, Chen-Chi M

    2015-05-15

    Titanium dioxide (TiO2)/ activated carbon (AC) composite materials, as capacitive deionization electrodes, were prepared by a two-step microwave-assisted ionothermal synthesis method. The electrosorption capacity of the composite electrodes was studied and the effects of AC characteristics were explored. These effects were investigated by multiple analytical techniques, including X-ray photoelectron spectroscopy, thermogravimetry analysis and electrochemical impedance spectroscopy, etc. The experimental results indicated that the electrosorption capacity of the TiO2/AC composite electrode is dependent on the characteristics of AC including the pore structure and the surface property. An enhancement in electrosorption capacity was observed for the TiO2/AC composite electrode prepared from the AC with higher mesopore content and less hydrophilic surface. This enhancement is due to the deposition of anatase TiO2 with suitable amount of Ti-OH. On the other hand, a decline in electrosorption capacity was observed for the TiO2/AC composite electrode prepared from the AC with higher micropore content and highly hydrophilic surface. High content of hydrogen bond complex formed between the functional group on hydrophilic surface with H2O, which will slow down the TiO2 precursor-H2O reaction. In such situation, the effect of TiO2 becomes unfavorable as the loading amount of TiO2 is less and the micropore can also be blocked.

  16. Nanostructured Zinc Oxide Materials for Use as Dye Sensitized Solar Cell Working Electrodes and Photocatalysts

    NASA Astrophysics Data System (ADS)

    Chang, Roger

    Since their invention in 1991, dye-sensitized solar cells (DSCs) have been the subject of intense research interest owing to their low cost, ease of manufacture and potential for low-light applications. In this thesis, the focus is on replacing TiO2 with ZnO, a semiconductor that exhibits much higher electron mobility. The shape of the ZnO nanomaterial is investigated in order to determine if shape and connectivity play a role in how best to exploit the high electron mobility of ZnO. When ZnO nanoparticles are replaced with 1-D nanowires in a DSC, it has been shown that electron transport is improved as measured by faster electron transport times and high electron diffusion coefficients. However, despite these electron transport advantages, ZnO nanowire-based DSCs still suffer from lower efficiencies than ZnO nanoparticle-based DSCs because of their much smaller surface area for dye loading. In the thesis work, zinc oxide nanorods are introduced as a compromise material that can maintain a large surface area, while taking advantage of 1-D fast electron transport. It is shown that by changing the shape of the semiconductor nanomaterial to elongated nanorods, electron transport time, electron lifetime, electron diffusivity and other measures of DSC performance are enhanced. Additionally, electrodeposition into hard templates was used to fabricate ZnO nanowires with magnetic Ni caps. The electrodeposited Ni-ZnO nanowires are shown to be useful in catalyzing the photodegradation of methylene blue (MB) , a model organic dye, and the result is compared to ZnO nanoparticles. The elongated shape of the nanowires is expected to prevent the aggregation that reduces the catalytic efficacy of ZnO nanoparticles, whereas the Ni segment is expected to enhance photocatalysis by increasing the production of radical hydroxide species that degrade the dye. Our experiments show that Ni-ZnO nanowires are more effective photocatalysts than ZnO nanoparticles as measured by the decrease

  17. Attenuation of intense sinusoidal waves in air-saturated, bulk porous materials

    NASA Technical Reports Server (NTRS)

    Kuntz, Herbert L.; Blackstock, David T.

    1987-01-01

    As intense, initially sinusoidal waves propagate in fluids, shocks form and excess attenuation of the wave occurs. Data are presented indicating that shock formation is not necessary for the occurrence of excess attenuation in nonlinear, lossy media, i.e., air-saturated, porous materials. An empirical equation is used to describe the excess attenuation of intense sinusoids in porous materials. The acoustic nonlinearity of and the excess attenuation in porous materials may be predicted directly from dc flow resistivity data. An empirical relationship is used to relate an acoustic nonlinearity parameter to the fundamental frequency and relative dc nonlinearity of two structurally different materials.

  18. Ingot niobium as candidate electrode material for Jefferson Lab 200 kV inverted electron photogun

    SciTech Connect

    BastaniNejad, Mahzad; Suleiman, Riad

    2015-12-04

    This contribution describes the field emission characterization of niobium electrodes using a DC high voltage field emission test apparatus. A total of six electrodes were evaluated: two large-grain, two single-crystal, and two fine-grain that were chemically polished using a buffered-chemical acid solution. Field emission from niobium electrodes could be significantly reduced and sometimes completely eliminated, by introducing krypton gas into the vacuum chamber while the electrode is biased at high voltage. Of all the electrodes tested, a large-grain niobium electrode performed the best, exhibiting no measurable field emission (<10 pA) at 225 kV with 20 mm cathode/anode gap, corresponding to a field strength of 18.7 MV/m. Motivated by these results, an inverted electron photogun operated at Jefferson Lab injector test facility was equipped with a large-grain niobium cathode electrode and it has been successfully conditioned to 225 kV without field emission. This photogun was used to study strained superlattice GaAs and K{sub 2}CsSb photocathodes at high beam currents.

  19. Solvothermal synthesis of NiAl double hydroxide microspheres on a nickel foam-graphene as an electrode material for pseudo-capacitors

    SciTech Connect

    Momodu, Damilola; Bello, Abdulhakeem; Dangbegnon, Julien; Barzeger, Farshad; Taghizadeh, Fatimeh; Fabiane, Mopeli; Manyala, Ncholu; Johnson, A. T. Charlie

    2014-09-15

    In this paper, we demonstrate excellent pseudo-capacitance behavior of nickel-aluminum double hydroxide microspheres (NiAl DHM) synthesized by a facile solvothermal technique using tertbutanol as a structure-directing agent on nickel foam-graphene (NF-G) current collector as compared to use of nickel foam current collector alone. The structure and surface morphology were studied by X-ray diffraction analysis, Raman spectroscopy and scanning and transmission electron microscopies respectively. NF-G current collector was fabricated by chemical vapor deposition followed by an ex situ coating method of NiAl DHM active material which forms a composite electrode. The pseudocapacitive performance of the composite electrode was investigated by cyclic voltammetry, constant charge–discharge and electrochemical impedance spectroscopy measurements. The composite electrode with the NF-G current collector exhibits an enhanced electrochemical performance due to the presence of the conductive graphene layer on the nickel foam and gives a specific capacitance of 1252 F g{sup −1} at a current density of 1 A g{sup −1} and a capacitive retention of about 97% after 1000 charge–discharge cycles. This shows that these composites are promising electrode materials for energy storage devices.

  20. Measurement of the resistivity of porous materials with an alternating air-flow method.

    PubMed

    Dragonetti, Raffaele; Ianniello, Carmine; Romano, Rosario A

    2011-02-01

    Air-flow resistivity is a main parameter governing the acoustic behavior of porous materials for sound absorption. The international standard ISO 9053 specifies two different methods to measure the air-flow resistivity, namely a steady-state air-flow method and an alternating air-flow method. The latter is realized by the measurement of the sound pressure at 2 Hz in a small rigid volume closed partially by the test sample. This cavity is excited with a known volume-velocity sound source implemented often with a motor-driven piston oscillating with prescribed area and displacement magnitude. Measurements at 2 Hz require special instrumentation and care. The authors suggest an alternating air-flow method based on the ratio of sound pressures measured at frequencies higher than 2 Hz inside two cavities coupled through a conventional loudspeaker. The basic method showed that the imaginary part of the sound pressure ratio is useful for the evaluation of the air-flow resistance. Criteria are discussed about the choice of a frequency range suitable to perform simplified calculations with respect to the basic method. These criteria depend on the sample thickness, its nonacoustic parameters, and the measurement apparatus as well. The proposed measurement method was tested successfully with various types of acoustic materials.