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Sample records for oxide cathode material

  1. New Cathode Materials for Intermediate Temperature Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Allan J. Jacobson

    2006-09-30

    Operation of SOFCs at intermediate temperatures (500-800 C) requires new combinations of electrolyte and electrode materials that will provide both rapid ion transport across the electrolyte and electrode-electrolyte interfaces and efficient electrocatalysis of the oxygen reduction and fuel oxidation reactions. This project concentrates on materials and issues associated with cathode performance that are known to become limiting factors as the operating temperature is reduced. The specific objectives of the proposed research are to develop cathode materials that meet the electrode performance targets of 1.0 W/cm{sup 2} at 0.7 V in combination with YSZ at 700 C and with GDC, LSGM or bismuth oxide based electrolytes at 600 C. The performance targets imply an area specific resistance of {approx}0.5 {Omega}cm{sup 2} for the total cell. The research strategy is to investigate both established classes of materials and new candidates as cathodes, to determine fundamental performance parameters such as bulk diffusion, surface reactivity and interfacial transfer, and to couple these parameters to performance in single cell tests. The initial choices for study were perovskite oxides based on substituted LaFeO{sub 3} (P1 compositions), where significant data in single cell tests exist at PNNL for example, for La{sub 0.8}Sr{sub 0.2}FeO{sub 3} cathodes on both YSZ and CSO/YSZ. The materials selection was then extended to La{sub 2}NiO{sub 4} compositions (K1 compositions), and then in a longer range task we evaluated the possibility of completely unexplored group of materials that are also perovskite related, the ABM{sub 2}O{sub 5+{delta}}. A key component of the research strategy was to evaluate for each cathode material composition, the key performance parameters, including ionic and electronic conductivity, surface exchange rates, stability with respect to the specific electrolyte choice, and thermal expansion coefficients. In the initial phase, we did this in parallel with

  2. Cathode material for lithium batteries

    Science.gov (United States)

    Park, Sang-Ho; Amine, Khalil

    2013-07-23

    A method of manufacture an article of a cathode (positive electrode) material for lithium batteries. The cathode material is a lithium molybdenum composite transition metal oxide material and is prepared by mixing in a solid state an intermediate molybdenum composite transition metal oxide and a lithium source. The mixture is thermally treated to obtain the lithium molybdenum composite transition metal oxide cathode material.

  3. Triple-conducting layered perovskites as cathode materials for proton-conducting solid oxide fuel cells.

    Science.gov (United States)

    Kim, Junyoung; Sengodan, Sivaprakash; Kwon, Goeun; Ding, Dong; Shin, Jeeyoung; Liu, Meilin; Kim, Guntae

    2014-10-01

    We report on an excellent anode-supported H(+) -SOFC material system using a triple conducting (H(+) /O(2-) /e(-) ) oxide (TCO) as a cathode material for H(+) -SOFCs. Generally, mixed ionic (O(2-) ) and electronic conductors (MIECs) have been selected as the cathode material of H(+) -SOFCs. In an H(+) -SOFC system, however, MIEC cathodes limit the electrochemically active sites to the interface between the proton conducting electrolyte and the cathode. New approaches to the tailoring of cathode materials for H(+) -SOFCs should therefore be considered. TCOs can effectively extend the electrochemically active sites from the interface between the cathode and the electrolyte to the entire surface of the cathode. The electrochemical performance of NBSCF/BZCYYb/BZCYYb-NiO shows excellent long term stability for 500 h at 1023 K with high power density of 1.61 W cm(-2) . © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    Science.gov (United States)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  5. Cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

    Science.gov (United States)

    Jacobson, Allan J; Wang, Shuangyan; Kim, Gun Tae

    2014-01-28

    Novel cathode, electrolyte and oxygen separation materials are disclosed that operate at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes based on oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

  6. Statistical analysis on hollow and core-shell structured vanadium oxide microspheres as cathode materials for Lithium ion batteries

    Directory of Open Access Journals (Sweden)

    Xing Liang

    2018-06-01

    Full Text Available In this data, the statistical analyses of vanadium oxide microspheres cathode materials are presented for the research article entitled “Statistical analyses on hollow and core-shell structured vanadium oxides microspheres as cathode materials for Lithium ion batteries” (Liang et al., 2017 [1]. This article shows the statistical analyses on N2 adsorption-desorption isotherm and morphology vanadium oxide microspheres as cathode materials for LIBs. Keywords: Adsorption-desorption isotherm, Pore size distribution, SEM images, TEM images

  7. Oxide Fiber Cathode Materials for Rechargeable Lithium Cells

    Science.gov (United States)

    Rice, Catherine E.; Welker, Mark F.

    2008-01-01

    LiCoO2 and LiNiO2 fibers have been investigated as alternatives to LiCoO2 and LiNiO2 powders used as lithium-intercalation compounds in cathodes of rechargeable lithium-ion electrochemical cells. In making such a cathode, LiCoO2 or LiNiO2 powder is mixed with a binder [e.g., poly(vinylidene fluoride)] and an electrically conductive additive (usually carbon) and the mixture is pressed to form a disk. The binder and conductive additive contribute weight and volume, reducing the specific energy and energy density, respectively. In contrast, LiCoO2 or LiNiO2 fibers can be pressed and sintered to form a cathode, without need for a binder or a conductive additive. The inter-grain contacts of the fibers are stronger and have fewer defects than do those of powder particles. These characteristics translate to increased flexibility and greater resilience on cycling and, consequently, to reduced loss of capacity from cycle to cycle. Moreover, in comparison with a powder-based cathode, a fiber-based cathode is expected to exhibit significantly greater ionic and electronic conduction along the axes of the fibers. Results of preliminary charge/discharge-cycling tests suggest that energy densities of LiCoO2- and LiNiO2-fiber cathodes are approximately double those of the corresponding powder-based cathodes.

  8. Study of bismuth oxide compounds as cathodic materials in lithium accumulators

    International Nuclear Information System (INIS)

    Apostolova, R.D.; Shembel', E.M.

    1999-01-01

    Two groups of bismuth oxide base compounds: rare earth bismuthides - SmBiO 3 and EuBiO 3 , as well as the Aurivillius phase - Bi 4 V 2 O 11 , were synthesized and electrochemically studied as novel cathodic materials for high-energy lithium current sources [ru

  9. Cathode materials review

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, Claus, E-mail: danielc@ornl.gov; Mohanty, Debasish, E-mail: danielc@ornl.gov; Li, Jianlin, E-mail: danielc@ornl.gov; Wood, David L., E-mail: danielc@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS6472 Oak Ridge, TN 37831-6472 (United States)

    2014-06-16

    The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO{sub 2} cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

  10. Cathode materials review

    International Nuclear Information System (INIS)

    Daniel, Claus; Mohanty, Debasish; Li, Jianlin; Wood, David L.

    2014-01-01

    The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO 2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research

  11. Cathode materials review

    Science.gov (United States)

    Daniel, Claus; Mohanty, Debasish; Li, Jianlin; Wood, David L.

    2014-06-01

    The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

  12. Vanadium oxide nanotubes as cathode material for Mg-ion batteries

    DEFF Research Database (Denmark)

    Christensen, Christian Kolle; Sørensen, Daniel Risskov; Bøjesen, Espen Drath

    Vanadium oxide compounds as cathode material for secondary Li-ion batteries gained interest in the 1970’s due to high specific capacity (>250mAh/g), but showed substantial capacity fading.1 Developments in the control of nanostructured morphologies have led to more advanced materials, and recently...... vanadium oxide nanotubes (VOx-NT) were shown to perform well as a cathode material for Mg-ion batteries.2 The VOx-NTs are easily prepared via a hydrothermal process to form multiwalled scrolls of VO layer with primary amines interlayer spacer molecules.3 The tunable and relative large layer spacing 1-3 nm...... synchrotron powder X-ray diffraction measured during battery operation. These results indicate Mg-intercalation in the multiwalled VOx-NTs occurs within the space between the individual vanadium oxide layers while the underlying VOx frameworks constructing the walls are affected only to a minor degree...

  13. Co-free, iron perovskites as cathode materials for intermediate-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Shu-en [Engineering Research Center of Nano-Geo Materials of Ministry of Education, China University of Geosciences, Wuhan, 430074 (China); Texas Materials Institute, ETC 9.102, The University of Texas at Austin, Austin, TX 78712 (United States); Alonso, Jose Antonio [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Texas Materials Institute, ETC 9.102, The University of Texas at Austin, Austin, TX 78712 (United States); Goodenough, John B. [Texas Materials Institute, ETC 9.102, The University of Texas at Austin, Austin, TX 78712 (United States)

    2010-01-01

    We have developed a Co-free solid oxide fuel cell (SOFC) based upon Fe mixed oxides that gives an extraordinary performance in test-cells with H{sub 2} as fuel. As cathode material, the perovskite Sr{sub 0.9}K{sub 0.1}FeO{sub 3-{delta}} (SKFO) has been selected since it has an excellent ionic and electronic conductivity and long-term stability under oxidizing conditions; the characterization of this material included X-ray diffraction (XRD), thermal analysis, scanning microscopy and conductivity measurements. The electrodes were supported on a 300-{mu}m thick pellet of the electrolyte La{sub 0.8}Sr{sub 0.2}Ga{sub 0.83}Mg{sub 0.17}O{sub 3-{delta}} (LSGM) with Sr{sub 2}MgMoO{sub 6} as the anode and SKFO as the cathode. The test cells gave a maximum power density of 680 mW cm{sup -2} at 800 C and 850 mW cm{sup -2} at 850 C, with pure H{sub 2} as fuel. The electronic conductivity shows a change of regime at T {approx} 350 C that could correspond to the phase transition from tetragonal to cubic symmetry. The high-temperature regime is characterized by a metallic-like behavior. At 800 C the crystal structure contains 0.20(1) oxygen vacancies per formula unit randomly distributed over the oxygen sites (if a cubic symmetry is assumed). The presence of disordered vacancies could account, by itself, for the oxide-ion conductivity that is required for the mass transport across the cathode. The result is a competitive cathode material containing no cobalt that meets the target for the intermediate-temperature SOFC. (author)

  14. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    Science.gov (United States)

    Doeff, Marca M.; Peng, Marcus Y.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard C.

    1996-01-01

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

  15. Mechanism of chromium poisoning the conventional cathode material for solid oxide fuel cells

    Science.gov (United States)

    Zhang, Xiaoqiang; Yu, Guangsen; Zeng, Shumao; Parbey, Joseph; Xiao, Shuhao; Li, Baihai; Li, Tingshuai; Andersson, Martin

    2018-03-01

    Chromium poisoning the La0.875Sr0.125MnO3 (LSM) cathode for solid oxide fuel cells is a critical issue that can strongly affect the stability. In this study, we evaluate the temperature distribution in a SOFC based on a 3D model and then combine conductivity test and material computation to reveal the effects of chromium in SUS430 stainless steels on LSM conductivities. The starch concentration in LSM pellets and the applied pressure on the contact with interconnect materials show close relationships with the chromium poisoning behavior. The density functional theory (DFT) computing results indicate that chromium atoms preferably adsorb on the MnO2-terminated and La (Sr)-O-terminated (001) surfaces. The resulting conclusions are expected to deeply understand mechanism of chromium deactivating conventional cathodes at some typical operational conditions, and offer crucial information to optimize the structure to avoid the poisoning effect.

  16. Composite cathode materials development for intermediate temperature solid oxide fuel cell systems

    Science.gov (United States)

    Qin, Ya

    Solid oxide fuel cell (SOFC) systems are of particular interest as electrochemical power systems that can operate on various hydrocarbon fuels with high fuel-to-electrical energy conversion efficiency. Within the SOFC stack, La0.8Sr 0.2Ga0.8Mg0.115Co0.085O3-delta (LSGMC) has been reported as an optimized composition of lanthanum gallate based electrolytes to achieve higher oxygen ionic conductivity at intermediate temperatures, i.e., 500-700°C. The electrocatalytic properties of interfaces between LSGMC electrolytes and various candidate intermediate-temperature SOFC cathodes have been investigated. Sm0.5Sr0.5CoO 3-delta (SSC), and La0.6Sr0.4Co0.2Fe 0.8O3-delta (LSCF), in both pure and composite forms with LSGMC, were investigated with regards to both oxygen reduction and evolution, A range of composite cathode compositions, having ratios of SSC (in wt.%) with LSGMC (wt.%) spanning the compositions 9:1, 8:2, 7:3, 6:4 and 5:5, were investigated to determine the optimal cathode-electrolyte interface performance at intermediate temperatures. All LSGMC electrolyte and cathode powders were synthesized using the glycine-nitrate process (GNP). Symmetrical electrochemical cells were investigated with three-electrode linear dc polarization and ac impedance spectroscopy to characterize the kinetics of the interfacial reactions in detail. Composite cathodes were found to perform better than the single phase cathodes due to significantly reduced polarization resistances. Among those composite SSC-LSGMC cathodes, the 7:3 composition has demonstrated the highest current density at the equivalent overpotential values, indicating that 7:3 is an optimal mixing ratio of the composite cathode materials to achieve the best performance. For the composite SC-LSGMC cathode/LSGMC interface, the cathodic overpotential under 1 A/cm2 current density was as low as 0.085 V at 700°C, 0.062V at 750°C and 0.051V at 800°C in air. Composite LSCF-LSGMC cathode/LSGMC interfaces were found to have

  17. Properties of Copper Doped Neodymium Nickelate Oxide as Cathode Material for Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Lee Kyoung-Jin

    2016-06-01

    Full Text Available Mixed ionic and electronic conducting K2NiF4-type oxide, Nd2Ni1-xCuxO4+δ (x=0~1 powders were synthesized by solid state reaction technique and solid oxide fuel cells consisting of a Nd2Ni1-xCuxO4+δ cathode, a Ni-YSZ anode and ScSZ as an electrolyte were fabricated. The effect of copper substitution for nickel on the electrical and electrochemical properties was examined. Small amount of copper doping (x=0.2 resulted in the increased electrical conductivity and decreased polarization resistance. It appears that this phenomenon was associated with the high mean valence of nickel and copper and the resulting excess oxygen (δ. It was found that power densities of the cell with the Nd2Ni1-xCuxO4+δ (x=0.1 and 0.2 cathode were higher than that of the cell with the Nd2NiO4+δ cathode.

  18. Atmospheric Plasma Spraying Low-Temperature Cathode Materials for Solid Oxide Fuel Cells

    Science.gov (United States)

    Harris, J.; Kesler, O.

    2010-01-01

    Atmospheric plasma spraying (APS) is attractive for manufacturing solid oxide fuel cells (SOFCs) because it allows functional layers to be built rapidly with controlled microstructures. The technique allows SOFCs that operate at low temperatures (500-700 °C) to be fabricated by spraying directly onto robust and inexpensive metallic supports. However, standard cathode materials used in commercial SOFCs exhibit high polarization resistances at low operating temperatures. Therefore, alternative cathode materials with high performance at low temperatures are essential to facilitate the use of metallic supports. Coatings of lanthanum strontium cobalt ferrite (LSCF) were fabricated on steel substrates using axial-injection APS. The thickness and microstructure of the coating layers were evaluated, and x-ray diffraction analysis was performed on the coatings to detect material decomposition and the formation of undesired phases in the plasma. These results determined the envelope of plasma spray parameters in which coatings of LSCF can be manufactured, and the range of conditions in which composite cathode coatings could potentially be manufactured.

  19. Methods for using novel cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

    Science.gov (United States)

    Jacobson, Allan J.; Wang, Shuangyan; Kim, Gun Tae

    2016-01-12

    Methods using novel cathode, electrolyte and oxygen separation materials operating at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes include oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

  20. Fundamental degradation mechanisms of layered oxide Li-ion battery cathode materials: Methodology, insights and novel approaches

    International Nuclear Information System (INIS)

    Hausbrand, R.; Cherkashinin, G.; Ehrenberg, H.; Gröting, M.; Albe, K.; Hess, C.; Jaegermann, W.

    2015-01-01

    Graphical abstract: - Highlights: • Description of recent in operando and in situ analysis methodology. • Surface science approach using photoemission for analysis of cathode surfaces and interfaces. • Ageing and fatigue of layered oxide Li-ion battery cathode materials from the atomistic point of view. • Defect formation and electronic structure evolution as causes for cathode degradation. • Significance of interfacial energy alignment and contact potential for side reactions. - Abstract: This overview addresses the atomistic aspects of degradation of layered LiMO 2 (M = Ni, Co, Mn) oxide Li-ion battery cathode materials, aiming to shed light on the fundamental degradation mechanisms especially inside active cathode materials and at their interfaces. It includes recent results obtained by novel in situ/in operando diffraction methods, modelling, and quasi in situ surface science analysis. Degradation of the active cathode material occurs upon overcharge, resulting from a positive potential shift of the anode. Oxygen loss and eventual phase transformation resulting in dead regions are ascribed to changes in electronic structure and defect formation. The anode potential shift results from loss of free lithium due to side reactions occurring at electrode/electrolyte interfaces. Such side reactions are caused by electron transfer, and depend on the electron energy level alignment at the interface. Side reactions at electrode/electrolyte interfaces and capacity fade may be overcome by the use of suitable solid-state electrolytes and Li-containing anodes

  1. Effect of calcination temperature on microstructure and electrochemical performance of lithium-rich layered oxide cathode materials

    International Nuclear Information System (INIS)

    Ma, Quanxin; Peng, Fangwei; Li, Ruhong; Yin, Shibo; Dai, Changsong

    2016-01-01

    Highlights: • A series of Li-rich layered oxide cathode materials (Li_1_._2Mn_0_._5_6Ni_0_._1_6Co_0_._0_8O_2) were successfully synthesized via a two-step synthesis method. • The effects of calcination temperature on the cathode materials were researched in detail. • A well-crystallized layered structure was obtained as the calcination temperature increased. • The samples calcined in a range of 850–900 °C exhibited excellent electrochemical performance. - Abstract: Lithium-rich layered oxide cathode materials (Li_1_._2Mn_0_._5_6Ni_0_._1_6Co_0_._0_8O_2 (LLMO)) were synthesized via a two-step synthesis method involving co-precipitation and high-temperature calcination. The effects of calcination temperature on the cathode materials were studied in detail. Structural and morphological characterizations revealed that a well-crystallized layered structure was obtained at a higher calcination temperature. Electrochemical performance evaluation revealed that a cathode material obtained at a calcination temperature of 850 °C delivered a high initial discharge capacity of 266.8 mAh g"−"1 at a 0.1 C rate and a capacity retention rate of 95.8% after 100 cycles as well as excellent rate capability. Another sample calcinated at 900 °C exhibited good cycling stability. It is concluded that the structural stability and electrochemical performance of Li-rich layered oxide cathode materials were strongly dependent on calcination temperatures. The results suggest that a calcination temperature in a range of 850–900 °C could promote electrochemical performance of this type of cathode materials.

  2. Effect of calcination temperature on microstructure and electrochemical performance of lithium-rich layered oxide cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Quanxin; Peng, Fangwei; Li, Ruhong; Yin, Shibo; Dai, Changsong, E-mail: changsd@hit.edu.cn

    2016-11-15

    Highlights: • A series of Li-rich layered oxide cathode materials (Li{sub 1.2}Mn{sub 0.56}Ni{sub 0.16}Co{sub 0.08}O{sub 2}) were successfully synthesized via a two-step synthesis method. • The effects of calcination temperature on the cathode materials were researched in detail. • A well-crystallized layered structure was obtained as the calcination temperature increased. • The samples calcined in a range of 850–900 °C exhibited excellent electrochemical performance. - Abstract: Lithium-rich layered oxide cathode materials (Li{sub 1.2}Mn{sub 0.56}Ni{sub 0.16}Co{sub 0.08}O{sub 2} (LLMO)) were synthesized via a two-step synthesis method involving co-precipitation and high-temperature calcination. The effects of calcination temperature on the cathode materials were studied in detail. Structural and morphological characterizations revealed that a well-crystallized layered structure was obtained at a higher calcination temperature. Electrochemical performance evaluation revealed that a cathode material obtained at a calcination temperature of 850 °C delivered a high initial discharge capacity of 266.8 mAh g{sup −1} at a 0.1 C rate and a capacity retention rate of 95.8% after 100 cycles as well as excellent rate capability. Another sample calcinated at 900 °C exhibited good cycling stability. It is concluded that the structural stability and electrochemical performance of Li-rich layered oxide cathode materials were strongly dependent on calcination temperatures. The results suggest that a calcination temperature in a range of 850–900 °C could promote electrochemical performance of this type of cathode materials.

  3. Studies on the pressed yttrium oxide-tungsten matrix as a possible dispenser cathode material

    International Nuclear Information System (INIS)

    Yang, Fan; Wang, Jinshu; Liu, Wei; Liu, Xiang; Zhou, Meiling

    2015-01-01

    Yttrium oxide was chosen as the secondary emission substance based on calculation results through first principle theory method. A new kind of pressed yttrium oxide-tungsten matrix dispenser cathodes are prepared by a sol–gel method combined with high temperature sintering in dry hydrogen atmosphere. The results show that the growth of the grains is hampered by the pinning effect of Y 2 O 3 distributing uniformly between the tungsten particles, resulting in the formation of small grain size. It is found that Y 2 O 3 improves the secondary electron emission property, i.e., the secondary emission yield increases with the increase of Y 2 O 3 content in the samples. The maximum secondary emission yield δ max of the cathode with 15% amount of Y 2 O 3 can reach 2.92. Furthermore, the cathode shows a certain thermionic emission performance. The zero field emission current density J 0 of 4.18A/cm 2 has reached at 1050 °C b for this kind of cathode after being activated at 1200 °C b , which are much higher than that of rare earth oxide doped molybdenum (REO-Mo) cathode reported in the previous work. - Highlights: • Yttrium oxide was chosen as the secondary emission substance based on first principle calculation result. • A new kind of cathode has been successfully obtained. • Pressed yttrium oxide-tungsten matrix dispenser cathode exhibits good emission properties. • The improvement of the cathode emission can be well explained by the surface analysis results presented in this work

  4. Studies on the pressed yttrium oxide-tungsten matrix as a possible dispenser cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fan; Wang, Jinshu, E-mail: wangjsh@bjut.edu.cn; Liu, Wei; Liu, Xiang; Zhou, Meiling

    2015-01-15

    Yttrium oxide was chosen as the secondary emission substance based on calculation results through first principle theory method. A new kind of pressed yttrium oxide-tungsten matrix dispenser cathodes are prepared by a sol–gel method combined with high temperature sintering in dry hydrogen atmosphere. The results show that the growth of the grains is hampered by the pinning effect of Y{sub 2}O{sub 3} distributing uniformly between the tungsten particles, resulting in the formation of small grain size. It is found that Y{sub 2}O{sub 3} improves the secondary electron emission property, i.e., the secondary emission yield increases with the increase of Y{sub 2}O{sub 3} content in the samples. The maximum secondary emission yield δ{sub max} of the cathode with 15% amount of Y{sub 2}O{sub 3} can reach 2.92. Furthermore, the cathode shows a certain thermionic emission performance. The zero field emission current density J{sub 0} of 4.18A/cm{sup 2} has reached at 1050 °C{sub b} for this kind of cathode after being activated at 1200 °C{sub b}, which are much higher than that of rare earth oxide doped molybdenum (REO-Mo) cathode reported in the previous work. - Highlights: • Yttrium oxide was chosen as the secondary emission substance based on first principle calculation result. • A new kind of cathode has been successfully obtained. • Pressed yttrium oxide-tungsten matrix dispenser cathode exhibits good emission properties. • The improvement of the cathode emission can be well explained by the surface analysis results presented in this work.

  5. Strategies to curb structural changes of lithium/transition metal oxide cathode materials & the changes’ effects on thermal & cycling stability

    Science.gov (United States)

    Xiqian, Yu; Enyuan, Hu; Seongmin, Bak; Yong-Ning, Zhou; Xiao-Qing, Yang

    2016-01-01

    Structural transformation behaviors of several typical oxide cathode materials during a heating process are reviewed in detail to provide in-depth understanding of the key factors governing the thermal stability of these materials. We also discuss applying the information about heat induced structural evolution in the study of electrochemically induced structural changes. All these discussions are expected to provide valuable insights for designing oxide cathode materials with significantly improved structural stability for safe, long-life lithium ion batteries, as the safety of lithium-ion batteries is a critical issue; it is widely accepted that the thermal instability of the cathodes is one of the most critical factors in thermal runaway and related safety problems. Project supported by the U.S. Department of Energy, the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies (Grant No. DE-SC0012704).

  6. Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin

    International Nuclear Information System (INIS)

    Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O.

    2016-01-01

    Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca_3Co_4O_9, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

  7. Synthesis of lithium nickel cobalt manganese oxide cathode materials by infrared induction heating

    Science.gov (United States)

    Hsieh, Chien-Te; Chen, Yu-Fu; Pai, Chun-Ting; Mo, Chung-Yu

    2014-12-01

    This study adopts an in-situ infrared (IR) sintering incorporated with carbonization technique to synthesize carbon-coated LiNi1/3Co1/3Mn1/3O2 (LNCM) cathode materials for Li-ion batteries. Compared with electric resistance heating, the in-situ IR sintering is capable of rapidly producing highly-crystalline LNCM powders at 900 °C within a short period, i.e., 3 h in this case. Glucose additive is employed to serve a carbon precursor, which is carbonized and coated over the surface of LNCM crystals during the IR sintering process. The electrochemical performance of LNCM cathodes is well examined by charge-discharge cycling at 0.1-5C. An appropriate carbon coating is capable of raising discharge capacity (i.e., 181.5 mAh g-1 at 0.1C), rate capability (i.e., 75.0 mAh g-1 at 5C), and cycling stability (i.e., capacity retention: 94.2% at 1C after 50 cycles) of LNCM cathodes. This enhanced performance can be ascribed to the carbon coating onto the external surface of LNCM powders, creating an outer circuit of charge-transfer pathway and preventing cathode corrosion from direct contact to the electrolyte. Accordingly, the in-situ IR sintering technique offers a potential feasibility for synthesizing cathode materials commercially in large scale.

  8. Defect physics vis-à-vis electrochemical performance in layered mixed-metal oxide cathode materials

    Science.gov (United States)

    Hoang, Khang; Johannes, Michelle

    Layered mixed-metal oxides with different compositions of (Ni,Co,Mn) [NCM] or (Ni,Co,Al) [NCA] have been used in commercial lithium-ion batteries. Yet their defect physics and chemistry is still not well understood, despite having important implications for the electrochemical performance. In this presentation, we report a hybrid density functional study of intrinsic point defects in the compositions LiNi1/3Co1/3Mn1/3O2 (NCM1/3) and LiNi1/3Co1/3Al1/3O2 (NCA1/3) which can also be regarded as model compounds for NCM and NCA. We will discuss defect landscapes in NCM1/3 and NCA1/3 under relevant synthesis conditions with a focus on the formation of metal antisite defects and its implications on the electrochemical properties and ultimately the design of NCM and NCA cathode materials.

  9. About the Compatibility between High Voltage Spinel Cathode Materials and Solid Oxide Electrolytes as a Function of Temperature.

    Science.gov (United States)

    Miara, Lincoln; Windmüller, Anna; Tsai, Chih-Long; Richards, William D; Ma, Qianli; Uhlenbruck, Sven; Guillon, Olivier; Ceder, Gerbrand

    2016-10-12

    The reactivity of mixtures of high voltage spinel cathode materials Li 2 NiMn 3 O 8 , Li 2 FeMn 3 O 8 , and LiCoMnO 4 cosintered with Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 and Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 electrolytes is studied by thermal analysis using X-ray-diffraction and differential thermoanalysis and thermogravimetry coupled with mass spectrometry. The results are compared with predicted decomposition reactions from first-principles calculations. Decomposition of the mixtures begins at 600 °C, significantly lower than the decomposition temperature of any component, especially the electrolytes. For the cathode + Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 mixtures, lithium and oxygen from the electrolyte react with the cathodes to form highly stable Li 2 MnO 3 and then decompose to form stable and often insulating phases such as La 2 Zr 2 O 7 , La 2 O 3 , La 3 TaO 7 , TiO 2 , and LaMnO 3 which are likely to increase the interfacial impedance of a cathode composite. The decomposition reactions are identified with high fidelity by first-principles calculations. For the cathode + Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 mixtures, the Mn tends to oxidize to MnO 2 or Mn 2 O 3 , supplying lithium to the electrolyte for the formation of Li 3 PO 4 and metal phosphates such as AlPO 4 and LiMPO 4 (M = Mn, Ni). The results indicate that high temperature cosintering to form dense cathode composites between spinel cathodes and oxide electrolytes will produce high impedance interfacial products, complicating solid state battery manufacturing.

  10. A versatile single molecular precursor for the synthesis of layered oxide cathode materials for Li-ion batteries.

    Science.gov (United States)

    Li, Maofan; Liu, Jiajie; Liu, Tongchao; Zhang, Mingjian; Pan, Feng

    2018-02-01

    A carbonyl-bridged single molecular precursor LiTM(acac) 3 [transition metal (TM) = cobalt/manganese/nickel (Co/Mn/Ni), acac = acetylacetone], featuring a one-dimensional chain structure, was designed and applied to achieve the layered oxide cathode materials: LiTMO 2 (TM = Ni/Mn/Co, NMC). As examples, layered oxides, primary LiCoO 2 , binary LiNi 0.8 Co 0.2 O 2 and ternary LiNi 0.5 Mn 0.3 Co 0.2 O 2 were successfully prepared to be used as cathode materials. When they are applied to lithium-ion batteries (LIBs), all exhibit good electrochemical performance because of their unique morphology and great uniformity of element distribution. This versatile precursor is predicted to accommodate many other metal cations, such as aluminum (Al 3+ ), iron (Fe 2+ ), and sodium (Na + ), because of the flexibility of organic ligand, which not only facilitates the doping-modification of the NMC system, but also enables synthesis of Na-ion layered oxides. This opens a new direction of research for the synthesis of high-performance layered oxide cathode materials for LIBs.

  11. Advanced cathode materials for polymer electrolyte fuel cells based on pt/ metal oxides: from model electrodes to catalyst systems.

    Science.gov (United States)

    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.

  12. A study of emission property and microstructure of rare earth oxide-molybdenum cermet cathode materials made by spark plasma sintering

    International Nuclear Information System (INIS)

    Wang Jinshu; Li Hongyi; Yang Sa; Cui Ying; Zhou Meiling

    2004-01-01

    A fast sintering method, spark plasma sintering (SPS) was used for the synthesis of rare earth oxide-molybdenum cathode material. The secondary emission property, microstructure, and phase constitution of materials have been studied in this paper. The experimental results show that the maximum secondary emission coefficient of this material can be high to 3.84, much higher than that of rare earth oxide-molybdenum cathode made by traditional sintering method. The grain size is less than 1 μm and rare earth distributed evenly in the material. After the material was activated at 1600 deg. C, a 4 μm layer of rare earth oxide which leads to the high secondary emission coefficient of the material, is formed on the surface of the cathode

  13. Crystallography and Growth of Epitaxial Oxide Films for Fundamental Studies of Cathode Materials Used in Advanced Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Leonid A. Bendersky

    2017-05-01

    Full Text Available Li-ion battery systems, synthesized as epitaxial thin films, can provide powerful insights into their electrochemical processes. Crystallographic analysis shows that many important cathode oxides have an underlying similarity: their structures can be considered as different ordering schemes of Li and transition metal ions within a pseudo-cubic sublattice of oxygen anions arranged in a face-center cubic (FCC fashion. This oxygen sublattice is compatible with SrTiO3 and similar perovskite oxides, thus perovskites can be used as supporting substrates for growing epitaxial cathode films. The predicted epitaxial growth and crystallographic relations were experimentally verified for different oxide films deposited by pulsed laser deposition (PLD on SrTiO3 or SrRuO3/SrTiO3 of different orientations. The results based on cross-sectional high-resolution TEM of the following films are presented in the paper: (a trigonal LiCoO2; (b orthorhombic LiMnO2; (c monoclinic Li2MnO3; (d compositionally-complex monoclinic Li1.2Mn0.55Ni0.15Co0.1O2. All results demonstrated the feasibility of epitaxial growth for these materials, with the growth following the predicted cube-on-cube orientation relationship between the cubic and pseudo-cubic oxygen sublattices of a substrate and a film, respectively.

  14. Cathode materials: A personal perspective

    Energy Technology Data Exchange (ETDEWEB)

    Goodenough, John B. [Texas Materials Institute, University of Texas at Austin, ETC 9.102, 1 University Station, Austin, TX 78712-1063 (United States)

    2007-12-06

    A thermodynamically stable rechargeable battery has a voltage limited by the window of the electrolyte. An aqueous electrolyte has a window of 1.2 eV, which prevents achieving the high energy density desired for many applications. A non-aqueous electrolyte with a window of 5 eV requires Li{sup +} rather than H{sup +} as the working ion. Early experiments with Li{sub x}TiS{sub 2} cathodes showed competitive capacity and rate capability, but problems with a lithium anode made the voltage of a safe cell based on a sulfide cathode too low to be competitive with a nickel/metal-hydride battery. Transition-metal oxides can give voltages of 4.5 V versus Li{sup +}/Li{sup 0}. However, the challenge with oxides has been to obtain a competitive capacity and rate capability while retaining a high voltage with low-cost, environmentally friendly cathode materials. Comparisons will be made between layered Li{sub 1-x}MO{sub 2}, spinels Li{sub 1-x}[M{sub 2}]O{sub 4}, and olivines Li{sub 1-x}MPO{sub 4} having 0 < x < 1. Although higher capacities can be obtained with layered Li{sub 1-x}MO{sub 2} compounds, which have enabled the wireless revolution, their metastability makes them unlikely to be used in power applications. The spinel and olivine framework structures have been shown to be capable of charge/discharge rates of over 10C with a suitable temperature range for plug-in hybrid vehicles. (author)

  15. The influence of reduced graphene oxide on electrical conductivity of LiFePO4-based composite as cathode material

    International Nuclear Information System (INIS)

    Arifin, Muhammad; Aimon, Akfiny Hasdi; Winata, Toto; Abdullah, Mikrajuddin; Iskandar, Ferry

    2016-01-01

    LiFePO 4 is fascinating cathode active materials for Li-ion batteries application because of their high electrochemical performance such as a stable voltage at 3.45 V and high specific capacity at 170 mAh.g −1 . However, their low intrinsic electronic conductivity and low ionic diffusion are still the hindrance for their further application on Li-ion batteries. Therefore, the efforts to improve their conductivity are very important to elevate their prospecting application as cathode materials. Herein, we reported preparation of additional of reduced Graphene Oxide (rGO) into LiFePO 4 -based composite via hydrothermal method and the influence of rGO on electrical conductivity of LiFePO 4 −based composite by varying mass of rGO in composition. Vibration of LiFePO 4 -based composite was detected on Fourier Transform Infrared Spectroscopy (FTIR) spectra, while single phase of LiFePO 4 nanocrystal was observed on X-Ray Diffraction (XRD) pattern, it furthermore, Scanning Electron Microscopy (SEM) images showed that rGO was distributed around LiFePO4-based composite. Finally, the 4-point probe measurement result confirmed that the optimum electrical conductivity is in additional 2 wt% rGO for range 1 to 2 wt% rGO

  16. Rare earth oxide doping in oxide cathodes

    International Nuclear Information System (INIS)

    Engelsen, Daniel den; Gaertner, Georg

    2006-01-01

    The effect on life performance and poisoning with O 2 by doping oxide cathodes with rare earth oxides and pseudo rare earth oxides, notably yttria, is qualitatively explained in terms of electrolysis of BaO during emission of electrons. Doped cathodes show less electrolysis and consume therefore less Ba during life: consequently, doped cathodes have a better life performance. However, the lower Ba-production makes doped cathodes more sensitive to oxygen poisoning. The experimentally found relation between conductivity and yttria concentration was the motive to propose a new model for the crystal imperfections in BaO. In this new imperfection model most Y 3+ -ions will combine with barium vacancies, therefore, the increase of the conductivity is modest and also the effect on the position of the Fermi level is modest. By assuming a combination of bulk and surface conductivity, the agreement between experiment and theory can be improved further

  17. Synthesis and characterization of Co-doped lanthanum nickelate perovskites for solid oxide fuel cell cathode material

    International Nuclear Information System (INIS)

    Chavez G, L.; Hinojosa R, M.; Medina L, B.; Ringuede, A.; Cassir, M.; Vannier, R. N.

    2017-01-01

    In the perovskite structures widely investigated and used as solid oxide fuel cells cathodes, oxygen reduction is mainly limited to the triple phase boundary (TPB), where oxygen (air), electrode and electrolyte are in contact. It is possible via the sol-gel modified Pechini method to: 1) control the material grain size, which can increase TPBs, 2) produce a homogenous material and 3) obtain a cathode material in a faster way compared with the solid state route. LaNi_xCo_1_-_xO_3 (x = 0.3, 0.5, 0.7) were synthesized by the modified Pechini method. The perovskite phase formation began at 350 degrees Celsius and the presence of pure LaNi_0_._7Co_0_._3O_3, LaNi_0_._5Co_0_._5O_3 and LaNi_0_._3Co_0_._7O_3 structures was evidenced by high temperature X-ray diffraction (Ht-XRD) measurements. Scanning electron microscopy (Sem) micrographs showed that the microstructure evolves with the amount of cobalt from a coalesced to an open structure. Electrochemical impedance spectroscopy (EIS) on symmetrical cells LaNi_xCo_1_-_xO_3/YSZ (Yttria-stabilized zirconia)/LaNi_xCo_1_-_xO_3 showed that the highest ASR (area specific resistance) is obtained with x = 0.3, whereas ASR values are similar for x = 0.5 and 0.7 at temperatures higher than 600 degrees Celsius. At temperatures lower than 600 degrees Celsius, ASR is the lowest for LaNi_0_._5Co_0_._5O_3, showing that this composition with intermediate porosity appears as a good choice for and intermediate-temperature solid oxid fuel cell. (Author)

  18. Strategies to curb structural changes of lithium/transition metal oxide cathode materials and the changes’ effects on thermal and cycling stability

    International Nuclear Information System (INIS)

    Yu Xiqian; Hu Enyuan; Bak, Seongmin; Zhou Yong-Ning; Yang Xiao-Qing

    2016-01-01

    Structural transformation behaviors of several typical oxide cathode materials during a heating process are reviewed in detail to provide in-depth understanding of the key factors governing the thermal stability of these materials. We also discuss applying the information about heat induced structural evolution in the study of electrochemically induced structural changes. All these discussions are expected to provide valuable insights for designing oxide cathode materials with significantly improved structural stability for safe, long-life lithium ion batteries, as the safety of lithium-ion batteries is a critical issue; it is widely accepted that the thermal instability of the cathodes is one of the most critical factors in thermal runaway and related safety problems. (topical review)

  19. Synthesis and characterization of gadolinia-doped ceria-silver cermet cathode material for solid oxide fuel cells

    International Nuclear Information System (INIS)

    Datta, Pradyot; Majewski, Peter; Aldinger, Fritz

    2008-01-01

    A series of Ce 0.9 Gd 0.1 O 2-δ -Ag cermets with different Ag contents were prepared by conventional sintering process aiming at assessing the suitability of using them as cathode material for solid oxide fuel cell (SOFC) with Gadolinia-doped ceria electrolyte. The chemical compatibility between Ce 0.9 Gd 0.1 O 2-δ (CGO) and Ag was investigated by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Thermal expansion coefficients of the cermets were measured as a function of Ag content and were found to increase with metallic content. Although oxygen adsorption at the surface of the cermets could be detected, no reaction or solid solubility between CGO and Ag was found

  20. Atomic-Resolution Visualization of Distinctive Chemical Mixing Behavior of Ni, Co and Mn with Li in Layered Lithium Transition-Metal Oxide Cathode Materials

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Pengfei; Zheng, Jianming; Lv, Dongping; Wei, Yi; Zheng, Jiaxin; Wang, Zhiguo; Kuppan, Saravanan; Yu, Jianguo; Luo, Langli; Edwards, Danny J.; Olszta, Matthew J.; Amine, Khalil; Liu, Jun; Xiao, Jie; Pan, Feng; Chen, Guoying; Zhang, Jiguang; Wang, Chong M.

    2015-07-06

    Capacity and voltage fading of layer structured cathode based on lithium transition metal oxide is closely related to the lattice position and migration behavior of the transition metal ions. However, it is scarcely clear about the behavior of each of these transition metal ions. We report direct atomic resolution visualization of interatomic layer mixing of transition metal (Ni, Co, Mn) and lithium ions in layer structured oxide cathodes for lithium ion batteries. Using chemical imaging with aberration corrected scanning transmission electron microscope (STEM) and DFT calculations, we discovered that in the layered cathodes, Mn and Co tend to reside almost exclusively at the lattice site of transition metal (TM) layer in the structure or little interlayer mixing with Li. In contrast, Ni shows high degree of interlayer mixing with Li. The fraction of Ni ions reside in the Li layer followed a near linear dependence on total Ni concentration before reaching saturation. The observed distinctively different behavior of Ni with respect to Co and Mn provides new insights on both capacity and voltage fade in this class of cathode materials based on lithium and TM oxides, therefore providing scientific basis for selective tailoring of oxide cathode materials for enhanced performance.

  1. Electrochemical Characteristics of Layered Transition Metal Oxide Cathode Materials for Lithium Ion Batteries: Surface, Bulk Behavior, and Thermal Properties.

    Science.gov (United States)

    Tian, Chixia; Lin, Feng; Doeff, Marca M

    2018-01-16

    Layered lithium transition metal oxides, in particular, NMCs (LiNi x Co y Mn z O 2 ) represent a family of prominent lithium ion battery cathode materials with the potential to increase energy densities and lifetime, reduce costs, and improve safety for electric vehicles and grid storage. Our work has focused on various strategies to improve performance and to understand the limitations to these strategies, which include altering compositions, utilizing cation substitutions, and charging to higher than usual potentials in cells. Understanding the effects of these strategies on surface and bulk behavior and correlating structure-performance relationships advance our understanding of NMC materials. This also provides information relevant to the efficacy of various approaches toward ensuring reliable operation of these materials in batteries intended for demanding traction and grid storage applications. In this Account, we start by comparing NMCs to the isostructural LiCoO 2 cathode, which is widely used in consumer batteries. Effects of changing the metal content (Ni, Mn, Co) upon structure and performance of NMCs are briefly discussed. Our early work on the effects of partial substitution of Al, Fe, and Ti for Co on the electrochemical and bulk structural properties is then covered. The original aim of this work was to reduce the Co content (and thus the raw materials cost) and to determine the effect of the substitutions on the electrochemical and bulk structural properties. More recently, we have turned to the application of synchrotron and advanced microscopy techniques to understand both bulk and surface characteristics of the NMCs. Via nanoscale-to-macroscale spectroscopy and atomically resolved imaging techniques, we were able to determine that the surfaces of NMC undergo heterogeneous reconstruction from a layered structure to rock salt under a variety of conditions. Interestingly, formation of rock salt also occurs under abuse conditions. The surface

  2. High Current Oxide Cathodes

    National Research Council Canada - National Science Library

    Luhmann, N

    2000-01-01

    The aim of the AASERT supported research is to develop the plasma deposition/implantation process for coating barium, strontium and calcium oxides on nickel substrates and to perform detailed surface...

  3. High Current Oxide Cathodes

    National Research Council Canada - National Science Library

    Luhmann, N

    2000-01-01

    .... The vacuum are plasma deposition gun developed at Lawrence Berkeley National Laboratory (LBNL) has been used to deposit oxides and nitrides with very precise control over deposition rate and composition.

  4. Towards deriving Ni-rich cathode and oxide-based anode materials from hydroxides by sharing a facile co-precipitation method.

    Science.gov (United States)

    Qiu, Haifa; Du, Tengfei; Wu, Junfeng; Wang, Yonglong; Liu, Jian; Ye, Shihai; Liu, Sheng

    2018-05-22

    Although intensive studies have been conducted on layered transition metal oxide(TMO)-based cathode materials and metal oxide-based anode materials for Li-ion batteries, their precursors generally follow different or even complex synthesis routes. To share one route for preparing precursors of the cathode and anode materials, herein, we demonstrate a facile co-precipitation method to fabricate Ni-rich hydroxide precursors of Ni0.8Co0.1Mn0.1(OH)2. Ni-rich layered oxide of LiNi0.8Co0.1Mn0.1O2 is obtained by lithiation of the precursor in air. An NiO-based anode material is prepared by calcining the precursor or multi-walled carbon nanotubes (MWCNTs) incorporated precursors. The pre-addition of ammonia solution can simplify the co-precipitation procedures and the use of an air atmosphere can also make the heat treatment facile. LiNi0.8Co0.1Mn0.1O2 as the cathode material delivers a reversible capacity of 194 mA h g-1 at 40 mA g-1 and a notable cycling retention of 88.8% after 100 cycles at 200 mA g-1. This noticeable performance of the cathode arises from a decent particle morphology and high crystallinity of the layered oxides. As the anode material, the MWCNTs-incorporated oxides deliver a much higher reversible capacity of 811.1 mA h g-1 after 200 cycles compared to the pristine oxides without MWCNTs. The improvement on electrochemical performance can be attributed to synergistic effects from MWCNTs incorporation, including reinforced electronic conductivity, rich meso-pores and an alleviated volume effect. This facile and sharing method may offer an integrated and economical approach for commercial production of Ni-rich electrode materials for Li-ion batteries.

  5. 2013 Estorm - Invited Paper - Cathode Materials Review

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, Claus [ORNL; Mohanty, Debasish [ORNL; Li, Jianlin [ORNL; Wood III, David L [ORNL

    2014-01-01

    The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403 431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783 789) demonstrated a high-energy and high-power LiCoO2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

  6. Building Honeycomb-Like Hollow Microsphere Architecture in a Bubble Template Reaction for High-Performance Lithium-Rich Layered Oxide Cathode Materials.

    Science.gov (United States)

    Chen, Zhaoyong; Yan, Xiaoyan; Xu, Ming; Cao, Kaifeng; Zhu, Huali; Li, Lingjun; Duan, Junfei

    2017-09-13

    In the family of high-performance cathode materials for lithium-ion batteries, lithium-rich layered oxides come out in front because of a high reversible capacity exceeding 250 mAh g -1 . However, the long-term energy retention and high energy densities for lithium-rich layered oxide cathode materials require a stable structure with large surface areas. Here we propose a "bubble template" reaction to build "honeycomb-like" hollow microsphere architecture for a Li 1.2 Mn 0.52 Ni 0.2 Co 0.08 O 2 cathode material. Our material is designed with ca. 8-μm-sized secondary particles with hollow and highly exposed porous structures that promise a large flexible volume to achieve superior structure stability and high rate capability. Our preliminary electrochemical experiments show a high capacity of 287 mAh g -1 at 0.1 C and a capacity retention of 96% after 100 cycles at 1.0 C. Furthermore, the rate capability is superior without any other modifications, reaching 197 mAh g -1 at 3.0 C with a capacity retention of 94% after 100 cycles. This approach may shed light on a new material engineering for high-performance cathode materials.

  7. Synthesis and characterization of Co-doped lanthanum nickelate perovskites for solid oxide fuel cell cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Chavez G, L.; Hinojosa R, M. [Universidad Autonoma de Nuevo Leon, Ciudad Universitaria, San Nicolas de los Garza, 66450 Nuevo Leon (Mexico); Medina L, B.; Ringuede, A.; Cassir, M. [Institut de Recherche de Chimie Paris, CNRS-Chimie ParisTech, 11 rue Pierre et Marie Curie, 75005 Paris (France); Vannier, R. N., E-mail: leonardo.chavezgr@uanl.edu.mx [Unite de Catalyse et de Chimie du Solide, UMR 8181 CNRS, 59655, Villeneuve d Ascq Cedex (France)

    2017-11-01

    In the perovskite structures widely investigated and used as solid oxide fuel cells cathodes, oxygen reduction is mainly limited to the triple phase boundary (TPB), where oxygen (air), electrode and electrolyte are in contact. It is possible via the sol-gel modified Pechini method to: 1) control the material grain size, which can increase TPBs, 2) produce a homogenous material and 3) obtain a cathode material in a faster way compared with the solid state route. LaNi{sub x}Co{sub 1-x}O{sub 3} (x = 0.3, 0.5, 0.7) were synthesized by the modified Pechini method. The perovskite phase formation began at 350 degrees Celsius and the presence of pure LaNi{sub 0.7}Co{sub 0.3}O{sub 3}, LaNi{sub 0.5}Co{sub 0.5}O{sub 3} and LaNi{sub 0.3}Co{sub 0.7}O{sub 3} structures was evidenced by high temperature X-ray diffraction (Ht-XRD) measurements. Scanning electron microscopy (Sem) micrographs showed that the microstructure evolves with the amount of cobalt from a coalesced to an open structure. Electrochemical impedance spectroscopy (EIS) on symmetrical cells LaNi{sub x}Co{sub 1-x}O{sub 3}/YSZ (Yttria-stabilized zirconia)/LaNi{sub x}Co{sub 1-x}O{sub 3} showed that the highest ASR (area specific resistance) is obtained with x = 0.3, whereas ASR values are similar for x = 0.5 and 0.7 at temperatures higher than 600 degrees Celsius. At temperatures lower than 600 degrees Celsius, ASR is the lowest for LaNi{sub 0.5}Co{sub 0.5}O{sub 3}, showing that this composition with intermediate porosity appears as a good choice for and intermediate-temperature solid oxid fuel cell. (Author)

  8. SmBaCoCuO5+x as cathode material based on GDC electrolyte for intermediate-temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Lue Shiquan; Long, Guohui; Ji Yuan; Meng Xiangwei; Zhao Hongyuan; Sun Cuicui

    2011-01-01

    Research highlights: → We synthesize a new kind of layered perovskite SmBaCoCuO 5+x (SBCCO) as a cathode material of a solid oxide fuel cell. → There are some reports on the performance of cathodes in proton-conducting SOFCs based on BaCe 0.8 Sm 0.2 O 3-δ electrolyte. → However, to the best of our knowledge, the performance of SBCCO cathodes in oxygen-ion conducting SOFCs has not been reported to date. → In this work, the ceramic powder SBCCO is examined as a cathode for IT-SOFCs based on Ce 0.9 Gd 0.1 O 1.95 (GDC) electrolyte. - Abstract: The performance of SmBaCoCuO 5+x (SBCCO) cathode has been investigated for their potential utilization in intermediate-temperature solid oxide fuel cells (IT-SOFCs). The powder X-ray diffraction (XRD), thermal expansion and electrochemical performance on Ce 0.9 Gd 0.1 O 1.95 (GDC) electrolyte are evaluated. XRD results show that there is no chemical reaction between SBCCO cathode and GDC electrolyte when the temperature is below 950 o C. The thermal expansion coefficient (TEC) value of SBCCO is 15.53 x 10 -6 K -1 , which is ∼23% lower than the TEC of the SmBaCo 2 O 5+x (SBCO) sample. The electrochemical impedance spectra reveals that SBCCO symmetrical half-cells by sintering at 950 deg. C has the best electrochemical performance and the area specific resistance (ASR) of SBCCO cathode is as low as 0.086 Ω cm 2 at 800 o C. An electrolyte-supported fuel cell generates good performance with the maximum power density of 517 mW cm -2 at 800 deg. C in H 2 . Preliminary results indicate that SBCCO is promising as a cathode for IT-SOFCs.

  9. Plasma Deposition of Oxide-Coated Cathodes

    National Research Council Canada - National Science Library

    Umstattd, Ryan

    1998-01-01

    ...; such cathodes may also have applicability for lower current density continuous wave devices. This novel approach to manufacturing an oxide cathode eliminates the binders that may subsequently (and unpredictably...

  10. A high-capacity, low-cost layered sodium manganese oxide material as cathode for sodium-ion batteries.

    Science.gov (United States)

    Guo, Shaohua; Yu, Haijun; Jian, Zelang; Liu, Pan; Zhu, Yanbei; Guo, Xianwei; Chen, Mingwei; Ishida, Masayoshi; Zhou, Haoshen

    2014-08-01

    A layered sodium manganese oxide material (NaMn3 O5 ) is introduced as a novel cathode materials for sodium-ion batteries. Structural characterizations reveal a typical Birnessite structure with lamellar stacking of the synthetic nanosheets. Electrochemical tests reveal a particularly large discharge capacity of 219 mAh g(-1) in the voltage rang of 1.5-4.7 V vs. Na/Na(+) . With an average potential of 2.75 V versus sodium metal, layered NaMn3 O5 exhibits a high energy density of 602 Wh kg(-1) , and also presents good rate capability. Furthermore, the diffusion coefficient of sodium ions in the layered NaMn3 O5 electrode is investigated by using the galvanostatic intermittent titration technique. The results greatly contribute to the development of room-temperature sodium-ion batteries based on earth-abundant elements. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Hydrothermal synthesis of cathode materials

    Science.gov (United States)

    Chen, Jiajun; Wang, Shijun; Whittingham, M. Stanley

    A number of cathodes are being considered for the next generation of lithium ion batteries to replace the expensive LiCoO 2 presently used. Besides the layered oxides, such as LiNi yMn yCo 1-2 yO 2, a leading candidate is lithium iron phosphate with the olivine structure. Although this material is inherently low cost, a manufacturing process that produces electrochemically active LiFePO 4 at a low cost is also required. Hydrothermal reactions are one such possibility. A number of pure phosphates have been prepared using this technique, including LiFePO 4, LiMnPO 4 and LiCoPO 4; this method has also successfully produced mixed metal phosphates, such as LiFe 0.33Mn 0.33Co 0.33PO 4. Ascorbic acid was found to be better than hydrazine or sugar at preventing the formation of ferric ions in aqueous media. When conductive carbons are added to the reaction medium excellent electrochemical behavior is observed.

  12. Reduced Graphene Oxide Decorated Na3V2(PO43 Microspheres as Cathode Material With Advanced Sodium Storage Performance

    Directory of Open Access Journals (Sweden)

    Hezhang Chen

    2018-05-01

    Full Text Available Reduced graphene oxide (rGO sheet decorated Na3V2(PO43 (NVP microspheres were successfully synthesized by spray-drying method. The NVP microspheres were embedded by rGO sheets, and the surface of the particles were coated by rGO sheets and amorphous carbon. Thus, the carbon conductive network consisted of rGO sheets and amorphous carbon generated in the cathode material. NVP microspheres decorated with different content of rGO (about 0, 4, 8, and 12 wt% were investigated in this study. The electrochemical performance of NVP exhibited a significant enhancement after rGO introduction. The electrode containing about 8 wt% rGO (NVP/G8 showed the best rate and cycle performance. NVP/G8 electrode exhibited the discharge capacity of 64.0 mAh g−1 at 70°C, and achieved high capacity retention of 95.5% after cycling at 10°C for 100 cycles. The polarization of the electrode was inhibited by the introduction of rGO sheets. Meanwhile, compared with the pristine NVP electrode, NVP/G8 electrode exhibited small resistance and high diffusion coefficient of sodium ions.

  13. Three-dimensional interconnected cobalt oxide-carbon hollow spheres arrays as cathode materials for hybrid batteries

    Directory of Open Access Journals (Sweden)

    Jiye Zhan

    2016-06-01

    Full Text Available Hierarchical porous metal oxides arrays is critical for development of advanced energy storage devices. Herein, we report a facile template-assisted electro-deposition plus glucose decomposition method for synthesis of multilayer CoO/C hollow spheres arrays. The CoO/C arrays consist of multilayer interconnected hollow composite spheres with diameters of ∼350 nm as well as thin walls of ∼20 nm. Hierarchical hollow spheres architecture with 3D porous networks are achieved. As cathode of high-rate hybrid batteries, the multilayer CoO/C hollow sphere arrays exhibit impressive enhanced performances with a high capacity (73.5 mAh g−1 at 2 A g−1, and stable high-rate cycling life (70 mAh g−1 after 12,500 cycles at 2 A g−1. The improved electrochemical performance is owing to the composite hollow-sphere architecture with high contact area between the active materials and electrolyte as well as fast ion/electron transportation path.

  14. Octahedral magnesium manganese oxide molecular sieves as the cathode material of aqueous rechargeable magnesium-ion battery

    International Nuclear Information System (INIS)

    Zhang, Hongyu; Ye, Ke; Shao, Shuangxi; Wang, Xin; Cheng, Kui; Xiao, Xue; Wang, Guiling; Cao, Dianxue

    2017-01-01

    Highlights: • The mico-sheet Mg-OMS-1 is synthesized by a simple hydrothermal method. • The mechanism of Mg 2+ insertion/deinsertion from Mg-OMS-1 is explored. • The electrode exhibits a good electrochemical performance in MgCl 2 electrolyte. - Abstract: Aqueous magnesium-ion batteries have shown the desired properties of high safety characteristics, similar electrochemical properties to lithium and low cost for energy storage applications. The micro-sheet morphology of todorokite-type magnesium manganese oxide molecular sieve (Mg-OMS-1) material, which applies as a novel cathode material for magnesium-ion battery, is obtained by the simple hydrothermal method. The structure and morphology of the particles are confirmed by X-ray power diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma, scanning and transmission electron microscopy. The electrochemical performance of Mg-OMS-1 is researched by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and constant current charge-discharge measurement. Mg-OMS-1 shows a good battery behavior for Mg 2+ insertion and deinsertion in the aqueous electrolyte. When discharging at 10 mA g −1 in 0.2 mol dm −3 MgCl 2 aqueous electrolyte, the initial discharge capacity reaches 300 mAh g −1 . The specific capacity retention rate is 83.7% after cycling 300 times at 100 mA g −1 in 0.5 mol dm −3 MgCl 2 electrolyte with a columbic efficiency of nearly 100%.

  15. Synthesis of LiFePO4/C cathode material from ferric oxide and organic lithium salts

    International Nuclear Information System (INIS)

    Shi Zhongqi; Huang Ming; Huai Yongjian; Lin Ziji; Yang Kerun; Hu Xuebu; Deng Zhenghua

    2011-01-01

    Research highlights: → LiFePO 4 can be synthesized from Fe 2 O 3 by a sequence of free-radical reactions. → Organic lithium salts can avoid the composition segregation of the precursor. → Low cost ferric oxide and environmentally friendly distilled water are used. - Abstract: LiFePO 4 /C cathode material has been simply synthesized via a modified in situ solid-state reaction route using the raw materials of Fe 2 O 3 , NH 4 H 2 PO 4 , Li 2 C 2 O 4 and lithium polyacrylate (PAALi). The sintering temperature of LiFePO 4 /C precursor is studied by thermo-gravimetric (TG)/differential thermal analysis (DTA). The physical properties of LiFePO 4 /C are then investigated through analysis using by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and the electrochemical properties are investigated by electrochemical impedance spectra (EIS), cyclic voltammogram (CV) and constant current charge/discharge test. The LiFePO 4 /C composite with the particle size of ∼200 nm shows better discharge capacity (156.4 mAh g -1 ) than bare LiFePO 4 (52.3 mAh g -1 ) at 0.2 C due to the improved electronic conductivity which is demonstrated by EIS. The as-prepared LiFePO 4 /C through this method also shows excellent high-rate characteristic and cycle performance. The initial discharge capacity of the sample is 120.5 mAh g -1 and the capacity retention rate is 100.6% after 50 cycles at 5 C rate. The results prove that the using of organic lithium salts can obtain a high performance LiFePO 4 /C composite.

  16. Model of dopant action in oxide cathodes

    International Nuclear Information System (INIS)

    Engelsen, Daniel den; Gaertner, Georg

    2005-01-01

    The paper describes an electrochemical model, which largely explains the formation of Ba in the oxide cathode at activation and normal operation. In a non-doped oxide cathode electrolysis of BaO is, besides the exchange reaction from the activators in the cathode nickel, an important source of Ba. By doping with rare earth oxides the conductivity of the oxide layer increases, which implies that the potential difference during current drawing over the oxide layer becomes lower and electrolysis of BaO is suppressed. This implies that the part of the electronic conductivity of the (Ba,Sr)O layer induced by the dopants also controls the sensitivity for poisoning: the higher the dopant level, the larger the sensitivity for poisoning. Furthermore, the suppression of electrolysis during normal operation largely explains why doped oxide cathodes have a better life performance than non-doped cathodes. Finally a hypothesis on the enhancement of sintering upon doping is presented

  17. Synthesis of LiFePO{sub 4}/C cathode material from ferric oxide and organic lithium salts

    Energy Technology Data Exchange (ETDEWEB)

    Shi Zhongqi; Huang Ming [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); Huai Yongjian [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); China Aviation Lithium Battery Co., Ltd, Luoyang, Henan 471003 (China); Lin Ziji; Yang Kerun [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); Hu Xuebu [Department of Chemistry and Materials, Sichuan Normal University, Chengdu, Sichuan 610068 (China); Zhongke Laifang Power Science and Technology Co., Ltd., Chengdu, Sichuan 610041 (China); Deng Zhenghua, E-mail: zhdeng@cioc.ac.c [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); Zhongke Laifang Power Science and Technology Co., Ltd., Chengdu, Sichuan 610041 (China)

    2011-04-15

    Research highlights: {yields} LiFePO{sub 4} can be synthesized from Fe{sub 2}O{sub 3} by a sequence of free-radical reactions. {yields} Organic lithium salts can avoid the composition segregation of the precursor. {yields} Low cost ferric oxide and environmentally friendly distilled water are used. - Abstract: LiFePO{sub 4}/C cathode material has been simply synthesized via a modified in situ solid-state reaction route using the raw materials of Fe{sub 2}O{sub 3}, NH{sub 4}H{sub 2}PO{sub 4}, Li{sub 2}C{sub 2}O{sub 4} and lithium polyacrylate (PAALi). The sintering temperature of LiFePO{sub 4}/C precursor is studied by thermo-gravimetric (TG)/differential thermal analysis (DTA). The physical properties of LiFePO{sub 4}/C are then investigated through analysis using by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and the electrochemical properties are investigated by electrochemical impedance spectra (EIS), cyclic voltammogram (CV) and constant current charge/discharge test. The LiFePO{sub 4}/C composite with the particle size of {approx}200 nm shows better discharge capacity (156.4 mAh g{sup -1}) than bare LiFePO{sub 4} (52.3 mAh g{sup -1}) at 0.2 C due to the improved electronic conductivity which is demonstrated by EIS. The as-prepared LiFePO{sub 4}/C through this method also shows excellent high-rate characteristic and cycle performance. The initial discharge capacity of the sample is 120.5 mAh g{sup -1} and the capacity retention rate is 100.6% after 50 cycles at 5 C rate. The results prove that the using of organic lithium salts can obtain a high performance LiFePO{sub 4}/C composite.

  18. Layered SmBaCuCoO5+δ and SmBaCuFeO5+δ perovskite oxides as cathode materials for proton-conducting SOFCs

    International Nuclear Information System (INIS)

    Nian Qiong; Zhao Ling; He Beibei; Lin Bin; Peng Ranran; Meng Guangyao; Liu Xingqin

    2010-01-01

    A dense BaCe 0.8 Sm 0.2 O 5+δ (BCS) electrolyte was fabricated on a porous anode by in situ drop-coating to develop a simple and cost-effective route to fabricate proton-conducting solid oxide fuel cells (SOFCs). Layered perovskite-structure oxides SmBaCuCoO 5+δ (SBCC) and SmBaCuFeO 5+δ (SBCF) were prepared and the electrical conductivity, the thermal expansion coefficient and electrochemical performance were investigated as potential cathode materials for proton-conducting SOFCs. Thermal expansion coefficients of SBCC and SBCF were suitable for BCS electrolyte and the electrical conductivity of the SBCC is higher than that of the SBCF. The maximum power density of 449 mW cm 2 and 333 mW cm 2 at 700 o C were obtained for the SBCC/BCS/NiO-BCS and SBCF/BCS/NiO-BCS cells, respectively. The interfacial polarization resistances for SBCC and SBCF cathode are as low as 0.137 Ω cm -2 and 0.196 Ω cm -2 at 700 o C, respectively. The results indicate that the SBCC and SBCF are promising cathode materials for proton-conducting SOFCs.

  19. Vanadium oxide based cpd. useful as a cathode active material - is used in lithium or alkali metal batteries to prolong life cycles

    DEFF Research Database (Denmark)

    1997-01-01

    A mixt. of metallic iron particles and vanadium pentoxide contg. V in its pentavalent state in a liq. is reacted to convert at least some of the pentavalent V to its tetravalent state and form a gel. The liq. phase is then sepd. from the oxide based gel to obtain a solid material(I) comprising Fe......, V and oxygen where at least some of the V is in the tetravalent state. USE-(I) is a cathode active material in electric current producing storage cells. ADVANTAGE-Use of (I) in Li or alkali metal batteries gives prolonged life cycles.Storage cells using (I) have improved capacity during charge...

  20. Highly conductive cathode materials for Li-ion batteries prepared by thermal nanocrystallization of selected oxide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Pietrzak, T.K.; Wasiucionek, M.; Michalski, P.P.; Kaleta, A.; Garbarczyk, J.E., E-mail: garbar@if.pw.edu.pl

    2016-11-15

    Glassy analogs of two important cathode materials for Li-ion cells: V{sub 2}O{sub 5} and phosphoolivine LiFePO{sub 4} were heat-treated in order to prepare nanocrystallized materials with high electronic conductivity of up to 7 × 10{sup −2} S cm{sup −1} and ca 7 × 10{sup −3} S cm{sup −1} at 25 °C, respectively. There is a clear correlation between the crystallization phenomena and the increase in the electrical conductivity for both groups of glasses. Electrochemical tests of heat-treated glasses of the V{sub 2}O{sub 5}–P{sub 2}O{sub 5} system, used as cathodes in lithium cells confirm their good gravimetric capacity and reversibility. Heat-treatment of glasses of the Li{sub 2}O–FeO–V{sub 2}O{sub 5}–P{sub 2}O{sub 5} system also leads to a high increase in the conductivity and to formation of nanocrystalline grains in the glassy matrix, evidenced by HR-TEM images. The temperature dependence of the conductivity of these materials follows the Arrhenius formula. The presented results indicate that the overall increase in conductivity in nanocrystallized materials is due to good charge transport properties of their interfacial regions.

  1. S-containing copolymer as cathode material in poly(ethylene oxide)-based all-solid-state Li-S batteries

    Science.gov (United States)

    Gracia, Ismael; Ben Youcef, Hicham; Judez, Xabier; Oteo, Uxue; Zhang, Heng; Li, Chunmei; Rodriguez-Martinez, Lide M.; Armand, Michel

    2018-06-01

    Inverse vulcanization copolymers (p(S-DVB)) from the radical polymerization of elemental sulfur and divinylbenzene (DVB) have been studied as cathode active materials in poly(ethylene oxide) (PEO)-based all-solid-state Li-S cells. The Li-S cell comprising the optimized p(S-DVB) cathode (80:20 w/w S/DVB ratio) and lithium bis(fluorosulfonyl)imide/PEO (LiFSI/PEO) electrolyte shows high specific capacity (ca. 800 mAh g-1) and high Coulombic efficiency for 50 cycles. Most importantly, polysulfide (PS) shuttle is highly mitigated due to the strong interactions of PS species with polymer backbone in p(S-DVB). This is demonstrated by the stable cycling of the p(S-DVB)-based cell using lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)/PEO electrolyte, where successful charging cannot be achieved even at the first cycle with plain elemental S-based cathode material due to the severe PS shuttle phenomenon. These results suggest that inverse vulcanization copolymers are promising alternatives to elemental sulfur for enhancing the electrochemical performance of PEO-based all-solid-state Li-S cells.

  2. Characteristics of uranium oxide cathode for neutron streak camera

    International Nuclear Information System (INIS)

    Niki, H.; Itoga, K.; Yamanaka, M.; Yamanaka, T.; Yamanaka, C.

    1986-01-01

    In laser fusion research, time-resolved neutron measurements require 20ps resolution in order to obtain the time history of the D-T burn. Uranium oxide was expected to be a sensitive material as a cathode of a neutron streak camera because of its large fission cross section. The authors report their measurements of some characteristics of the uranium oxide cathode connected to a conventional streak tube. 14 MeV neutron signal were observed as the bright spots on a TV monitor using a focus mode opration. Detection efficiency was ∼ 1 x 10 -6 for 1 μm thick cathode. Each signal consisted of more than several tens of components, which were corresponding to the secondary electrons dragged out from the cathode by a fission fragment. Time resolution is thought to be limited mainly by the transit time spread of the secondary electrons. 14ps resolution was obtained by a streak mode operation for a single fission event

  3. Oxide cathodes produced by plasma deposition

    International Nuclear Information System (INIS)

    Scheitrum, G.; Caryotakis, G.; Pi, T.; Umstattd, R.; Brown, I.; Montiero, O.

    1997-01-01

    These are two distinct applications for high-current-density, long-life thermionic cathodes. The first application is as a substitute for explosive emission cathodes used in high-power microwave (HPM) devices being developed for Air Force programs. The second application is in SLAC's X-band klystrons for the Next Linear Collider (NLC). SLAC, UCD, and LBL are developing a plasma deposition process that eliminates the problems with binders, carbonate reduction, peeling, and porosity. The emission layer is deposited using plasma deposition of metallic barium in vacuum with an oxygen background gas. An applied bias voltage drives the oxide plasma into the nickel surface. Since the oxide is deposited directly, it does not have problems with poisoning from a hydrocarbon binder. The density of the oxide layer is increased from the 40--50% for standard oxide cathodes to nearly 100% for plasma deposition

  4. Developments in the Material Fabrication and Performance of LiMn2O4 dCld Cathode Material

    Science.gov (United States)

    2016-06-13

    manganese oxide spinel materials exhibit promising electrochemical performance and good thermodynamic and kinetic stability when used as a cathode in... oxide spinel (LiMn2O4) is a potential viable active cathode material for use in these versatile applications due to its low toxicity, good capacity...Developments in the Material Fabrication and Performance of LiMn2O4-dCld Cathode Material Paula C Latorre, Ashley L Ruth, and Terrill B Atwater

  5. The influence of reduced graphene oxide on electrical conductivity of LiFePO{sub 4}-based composite as cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Arifin, Muhammad; Aimon, Akfiny Hasdi; Winata, Toto; Abdullah, Mikrajuddin [Physics of Electronic Materials Research Division, Department of Physics, Institut Teknologi Bandung, Bandung 40132 Indonesia (Indonesia); Iskandar, Ferry, E-mail: ferry@fi.itb.ac.id [Physics of Electronic Materials Research Division, Department of Physics, Institut Teknologi Bandung, Bandung 40132 Indonesia (Indonesia); Research Center for Nanoscience and Nanotechnology Institut Teknologi Bandung, Bandung 40132 Indonesia (Indonesia)

    2016-02-08

    LiFePO{sub 4} is fascinating cathode active materials for Li-ion batteries application because of their high electrochemical performance such as a stable voltage at 3.45 V and high specific capacity at 170 mAh.g{sup −1}. However, their low intrinsic electronic conductivity and low ionic diffusion are still the hindrance for their further application on Li-ion batteries. Therefore, the efforts to improve their conductivity are very important to elevate their prospecting application as cathode materials. Herein, we reported preparation of additional of reduced Graphene Oxide (rGO) into LiFePO{sub 4}-based composite via hydrothermal method and the influence of rGO on electrical conductivity of LiFePO{sub 4}−based composite by varying mass of rGO in composition. Vibration of LiFePO{sub 4}-based composite was detected on Fourier Transform Infrared Spectroscopy (FTIR) spectra, while single phase of LiFePO{sub 4} nanocrystal was observed on X-Ray Diffraction (XRD) pattern, it furthermore, Scanning Electron Microscopy (SEM) images showed that rGO was distributed around LiFePO4-based composite. Finally, the 4-point probe measurement result confirmed that the optimum electrical conductivity is in additional 2 wt% rGO for range 1 to 2 wt% rGO.

  6. A facile method of preparing LiMnPO4/reduced graphene oxide aerogel as cathodic material for aqueous lithium-ion hybrid supercapacitors

    Science.gov (United States)

    Xu, Lin; Wang, Senlin; Zhang, Xiao; He, Taobin; Lu, Fengxia; Li, Huichang; Ye, Junhui

    2018-01-01

    A facile method of preparing LiMnPO4/reduced graphene oxide aerogel (LMP/rGO) as cathodic material was reported here. LiMnPO4 nano-particles were prepared using a facile polyvinyl pyrrolidone-assisted solvothermal route. Then LMP/rGO aerogel was prepared using the accessible restacking method. The influence of the cathodic electrode composition (ratio of rGO to LiMnPO4) on the performance of the LMP/rGO was evaluated by constant-current discharge tests. When compared with 217C g-1 for the pristine LMP, the best LMP/rGO (the content of rGO is 27.3 wt%) exhibits a higher capacity of 464.5C g-1 (at 0.5 A g-1), which presenting the capacity enhance of 114%. Moreover, a lithium-ion hybrid supercapacitor (LIHS) was successfully assembled by using LMP/rGO aerogel as the cathodic electrode and rGO aerogel as the anodic electrode. The LMP/rGO//rGO device achieves excellent specific energy of 16.46 W h kg-1 at a power density of 0.38 kW kg-1, even under the higher specific power of 4.52 kW kg-1, there still holds the specific energy of 11.79 W h kg-1. The LMP/rGO//rGO device maintains 91.2% of the initial capacity after 10,000 cycles (at 2 A g-1), which displays high rate performance and long cycle life. The 3D LMP/rGO aerogel could be a promising candidate material for the lithium-ion hybrid supercapacitors.

  7. Oxygen reduction kinetics and transport properties of (Ba,Sr)(Co,Fe)O3-δ solid oxide fuel cell cathode materials

    International Nuclear Information System (INIS)

    Wang, Lei; Merkle, Rotraut; Baumann, Frank S.; Maier, Joachim; Fleig, Juergen

    2007-01-01

    Full text: The oxygen reduction at the surface of cathode materials is crucial for the performance of solid oxide fuel cells (SOFC), but a detailed understanding of the mechanism is not available yet. (Ba x Sr 1-x )(Co 1-y Fe y )O 3-δ shows strongly improved oxygen reduction rates compared to previously applied perovskite cathode materials. In this work, surface rate constants as well as bulk transport properties are studied. (Ba x Sr 1-x )(Co 1-y Fe y )O 3-δ with 0≤x≤0.5, 0.2≤y≤1 was synthesized by the Pechini method. Oxygen stoichoimetry was obtained from thermo-gravimetric analysis, confirming that Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ has an exceptionally low oxygen content which is generally smaller than 2.5. Dense thin films were grown by pulsed laser deposition (PLD) and patterned into circular microelectrodes by photolithography. The surface resistance R s , which dominate the overall electrode resistance, were measured by impedance spectroscopy on individual microelectrodes at different T, pO 2 and applied electrical bias. PLD technique greatly helps to study the oxygen reduction kinetics since only measurements on dense thin films allow to record absolute R s values without interference from morphology effects. These R s values were found to be much lower than those for (La,Sr)(Co,Fe)O 3-δ . The variation of the surface reaction rates with A-site and B-site composition was studied and correlations with bulk materials properties such as oxygen nonstoichiometry, ionic mobility or oxidation enthalpy were examined. Plausible reaction mechanisms as well as possible reasons for the high absolute surface reaction rates will be discussed

  8. Evaluation of Ca3(Co,M2O6 (M=Co, Fe, Mn, Ni as new cathode materials for solid-oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Fushao Li

    2015-10-01

    Full Text Available Series compounds Ca3(Co0.9M0.12O6 (M=Co, Fe, Mn, Ni with hexagonal crystal structure were prepared by sol–gel route as the cathode materials for solid oxide fuel cells (SOFCs. Effects of the varied atomic compositions on the structure, electrical conductivity, thermal expansion and electrochemical performance were systematically evaluated. Experimental results showed that the lattice parameters of Ca3(Co0.9Fe0.12O6 and Ca3(Co0.9Mn0.12O6 were both expanded to certain degree. Electron-doping and hole-doping effects were expected in Ca3(Co0.9Mn0.12O6 and Ca3(Co0.9Ni0.12O6 respectively according to the chemical states of constituent elements and thermal-activated behavior of electrical conductivity. Thermal expansion coefficients (TEC of Ca3(Co0.9M0.12O6 were measured to be distributed around 16×10−6 K−1, and compositional elements of Fe, Mn, and Ni were especially beneficial for alleviation of the thermal expansion problem of cathode materials. By using Ca3(Co0.9M0.12O6 as the cathodes operated at 800 °C, the interfacial area-specific resistance varied in the order of M=Cocathode materials for SOFCs.

  9. Cathodes for Solid Oxide Fuel Cells Operating at Low Temperatures

    DEFF Research Database (Denmark)

    Samson, Alfred Junio

    . High performance cathodes were obtained from strontium-doped lanthanum cobaltite (LSC) infiltrated - Ce0.9Gd0.1O1.95 (CGO) ionic conducting backbone. Systematic tuning of the CGO and LSC firing temperatures and LSC loading resulted in a cathode with low polarization resistance, Rp = 0.044 cm2 at 600......This dissertation focuses on the development of nanostructured cathodes for solid oxide fuel cells (SOFCs) and their performance at low operating temperatures. Cathodes were mainly fabricated by the infiltration method, whereby electrocatalysts are introduced onto porous, ionic conducting backbones...... with increasing LSC firing temperature, highlighting the importance of materials compability over higher ionic conductivity. The potential of Ca3Co4O9+delta as an electrocatalyst for SOFCs has also been explored and encouraging results were found i.e., Rp = 0.64 cm2 for a Ca3Co4O9+delta/CGO 50 vol % composite...

  10. Defect Chemistry, Electrical Properties, and Evaluation of New Oxides Sr2 CoNb1-x Tix O6-δ (0≤x≤1) as Cathode Materials for Solid Oxide Fuel Cells.

    Science.gov (United States)

    Azcondo, María Teresa; Yuste, Mercedes; Pérez-Flores, Juan Carlos; Muñoz-Gil, Daniel; García-Martín, Susana; Muñoz-Noval, Alvaro; Orench, Inés Puente; García-Alvarado, Flaviano; Amador, Ulises

    2017-07-21

    The perovskite series Sr 2 CoNb 1-x Ti x O 6-δ (0≤x≤1) was investigated in the full compositional range to assess its potential as cathode material for solid oxide fuel cell (SOFC). The variation of transport properties and thus, the area specific resistances (ASR) are explained by a detailed investigation of the defect chemistry. Increasing the titanium content from x=0-1 produces both oxidation of Co 3+ to Co 4+ (from 0 up to 40 %) and oxygen vacancies (from 6.0 to 5.7 oxygen atom/formula unit), although each charge compensation mechanism predominates in different compositional ranges. Neutron diffraction reveals that samples with high Ti-contents lose a significant amount of oxygen upon heating above 600 K. Oxygen is partially recovered upon cooling as the oxygen release and uptake show noticeably different kinetics. The complex defect chemistry of these compounds, together with the compositional changes upon heating/cooling cycles and atmospheres, produce a complicated behavior of electrical conductivity. Cathodes containing Sr 2 CoTiO 6-δ display low ASR values, 0,13 Ω cm 2 at 973 K, comparable to those of the best compounds reported so far, being a very promising cathode material for SOFC. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. A soft chemical route to multicomponent lithium transition metal oxide nanowires as promising cathode materials for lithium secondary batteries

    International Nuclear Information System (INIS)

    Park, Dae-Hoon; Lim, Seung-Tae; Hwang, Seong-Ju

    2006-01-01

    We have synthesized 1D nanowires of lithium nickel manganese oxides with two different crystal structures through the chemical oxidation reaction of solid-state precursor LiMn 0.5 Ni 0.5 O 2 under hydrothermal condition. According to X-ray diffraction and elemental analyses, the nanowires obtained by persulfate treatments at 65 and 120 deg. C crystallize with a hexagonal layered and an α-MnO 2 -type structure, respectively, in which nickel and manganese ions exist in octahedral sites. Electron microscopic analyses reveal that the platelike crystallites of the precursor are changed into nanowires with the diameter of ∼20 nm after the persulfate treatment. Thermal and infrared spectroscopic analyses clearly demonstrate that, in comparison with α-MnO 2 -structured nanowires, the hexagonal layered nanowires contain less water molecules in the lattice, which makes them suitable for the application as electrode materials for lithium secondary batteries. According to electrochemical measurements, the hexagonal layered nanowires show a larger discharge capacity and an excellent cyclability with respect to repeated Li intercalation-disintercalation process. X-ray diffraction and electron microscopic analyses on the samples subjected to electrochemical analysis reveal that the layered structure and 1D morphology of the nanowires are still maintained after the electrochemical cyclings, which is responsible for their excellent electrochemical performances

  12. Lithium containing manganese dioxide (composite dimensional manganese oxide-CDMO) as a cathod active material for lithium secondary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, Nobuhiro; Noma, Toshiyuki; Teraji, Kazuo; Nakane, Ikuo; Yamamoto, Yuji; Saito, Toshihiko (Sanyo Electric Co., Ltd., Osaka, Japan)

    1989-06-05

    Manganese dioxide containing lithium ions in a solid matrix was investigated in the lithium nonaqueous cell. Li/sub x/MnO/sub 2+{delta}/ material prepared, with the thermal treatment, by the solid state reaction of manganese dioxide and lithium hydroxide, 7 to 3 in molar ratio, at the temperature of 375{sup 0}C in air for 20 hours, exhibited the rechargeability in the lithium nonaqueous cell. A discharging and changing cycle test, 0.14 or 0.26e/Mn in each of both the discharge and charge, was also made, with the use of a flat type cell, to demonstrate it in performance. Synthetic Li/sub x/MnO/sub 2+{delta}/ was discussed, in advantageous use for the secondary lithium cell, based on the discharging and charging characteristics. As a conclusion of the foregoing, composite dimensional manganese oxide is expected to be good as active material of positive electrode for the secondary lithium cell use. 11 refs., 11 figs., 3 tabs.

  13. Cobalt and cerium coated Ni powder as a new candidate cathode material for MCFC

    International Nuclear Information System (INIS)

    Kim, Min Hyuk; Hong, Ming Zi; Kim, Young-Suk; Park, Eunjoo; Lee, Hyunsuk; Ha, Hyung-Wook; Kim, Keon

    2006-01-01

    The dissolution of nickel oxide cathode in the electrolyte is one of the major technical obstacles to the commercialization of molten carbonate fuel cell (MCFC). To improve the MCFC cathode stability, the alternative cathode material for MCFC was prepared, which was made of Co/Ce-coated on the surface of Ni powder using a polymeric precursor based on the Pechini method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) were employed in characterization of the alternative cathode materials. The Co/Ce-coated Ni cathode prepared by the tape-casting technique. The solubility of the Co/Ce-coated Ni cathode was about 80% lower when compare to that of pure Ni cathode under CO 2 :O 2 (66.7:33.3%) atmosphere at 650 deg. C. Consequently, the fine Co/Ce-coated Ni powder could be confirmed as a new alternative cathode material for MCFC

  14. Preparation of Layered-Spinel Microsphere/Reduced Graphene Oxide Cathode Materials for Ultrafast Charge-Discharge Lithium-Ion Batteries.

    Science.gov (United States)

    Luo, Dong; Fang, Shaohua; Yang, Li; Hirano, Shin-Ichi

    2017-12-22

    Although Li-rich layered oxides (LLOs) have the highest capacity of any cathodes used, the rate capability of LLOs falls short of meeting the requirements of electric vehicles and smart grids. Herein, a layered-spinel microsphere/reduced graphene oxide heterostructured cathode (LS@rGO) is prepared in situ. This cathode is composed of a spinel phase, two layered structures, and a small amount of reduced graphene oxide (1.08 wt % of carbon). The assembly delivers a considerable charge capacity (145 mA h g -1 ) at an ultrahigh charge- discharge rate of 60 C (12 A g -1 ). The rate capability of LS@rGO is influenced by the introduced spinel phase and rGO. X-ray absorption and X-ray photoelectron spectroscopy data indicate that Cr ions move from octahedral lattice sites to tetrahedral lattice sites, and that Mn ions do not participate in the oxidation reaction during the initial charge process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Probing the Complexities of Structural Changes in Layered Oxide Cathode Materials for Li-Ion Batteries during Fast Charge-Discharge Cycling and Heating.

    Science.gov (United States)

    Hu, Enyuan; Wang, Xuelong; Yu, Xiqian; Yang, Xiao-Qing

    2018-02-20

    The rechargeable lithium-ion battery (LIB) is the most promising energy storage system to power electric vehicles with high energy density and long cycling life. However, in order to meet customers' demands for fast charging, the power performances of current LIBs need to be improved. From the cathode aspect, layer-structured cathode materials are widely used in today's market and will continue to play important roles in the near future. The high rate capability of layered cathode materials during charging and discharging is critical to the power performance of the whole cell and the thermal stability is closely related to the safety issues. Therefore, the in-depth understanding of structural changes of layered cathode materials during high rate charging/discharging and the thermal stability during heating are essential in developing new materials and improving current materials. Since structural changes take place from the atomic level to the whole electrode level, combination of characterization techniques covering multilength scales is quite important. In many cases, this means using comprehensive tools involving diffraction, spectroscopy, and imaging to differentiate the surface from the bulk and to obtain structural/chemical information with different levels of spatial resolution. For example, hard X-ray spectroscopy can yield the bulk information and soft X-ray spectroscopy can give the surface information; X-ray based imaging techniques can obtain spatial resolution of tens of nanometers, and electron-based microcopy can go to angstroms. In addition to challenges associated with different spatial resolution, the dynamic nature of structural changes during high rate cycling and heating requires characterization tools to have the capability of collecting high quality data in a time-resolved fashion. Thanks to the advancement in synchrotron based techniques and high-resolution electron microscopy, high temporal and spatial resolutions can now be achieved. In

  16. Material and Energy Flows in the Production of Cathode and Anode Materials for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); James, Christine [Michigan State Univ., East Lansing, MI (United States); Gaines, Linda [Argonne National Lab. (ANL), Argonne, IL (United States); Gallagher, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Dai, Qiang [Argonne National Lab. (ANL), Argonne, IL (United States); Kelly, Jarod C. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    The Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has been expanded to include four new cathode materials that can be used in the analysis of battery-powered vehicles: lithium nickel cobalt manganese oxide (LiNi0.4Co0.2Mn0.4O2 [NMC]), lithium iron phosphate (LiFePO4 [LFP]), lithium cobalt oxide (LiCoO2 [LCO]), and an advanced lithium cathode (0.5Li2MnO3∙0.5LiNi0.44Co0.25Mn0.31O2 [LMR-NMC]). In GREET, these cathode materials are incorporated into batteries with graphite anodes. In the case of the LMR-NMC cathode, the anode is either graphite or a graphite-silicon blend. Lithium metal is also an emerging anode material. This report documents the material and energy flows of producing each of these cathode and anode materials from raw material extraction through the preparation stage. For some cathode materials, we considered solid state and hydrothermal preparation methods. Further, we used Argonne National Laboratory’s Battery Performance and Cost (BatPaC) model to determine battery composition (e.g., masses of cathode, anode, electrolyte, housing materials) when different cathode materials were used in the battery. Our analysis concluded that cobalt- and nickel-containing compounds are the most energy intensive to produce.

  17. Material and Energy Flows in the Production of Cathode and Anode Materials for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; James, Christine [Michigan State Univ., East Lansing, MI (United States). Chemical Engineering and Materials Science Dept.; Gaines, Linda G. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Gallagher, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division

    2014-09-30

    The Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has been expanded to include four new cathode materials that can be used in the analysis of battery-powered vehicles: lithium nickel cobalt manganese oxide (LiNi0.4Co0.2Mn0.4O2 [NMC]), lithium iron phosphate (LiFePO4 [LFP]), lithium cobalt oxide (LiCoO2 [LCO]), and an advanced lithium cathode (0.5Li2MnO3∙0.5LiNi0.44Co0.25Mn0.31O2 [LMR-NMC]). In GREET, these cathode materials are incorporated into batteries with graphite anodes. In the case of the LMR-NMC cathode, the anode is either graphite or a graphite-silicon blend. This report documents the material and energy flows of producing each of these cathode and anode materials from raw material extraction through the preparation stage. For some cathode materials, we considered solid state and hydrothermal preparation methods. Further, we used Argonne National Laboratory’s Battery Performance and Cost (BatPaC) model to determine battery composition (e.g., masses of cathode, anode, electrolyte, housing materials) when different cathode materials were used in the battery. Our analysis concluded that cobalt- and nickel-containing compounds are the most energy intensive to produce.

  18. Laser microstructuring and annealing processes for lithium manganese oxide cathodes

    International Nuclear Information System (INIS)

    Proell, J.; Kohler, R.; Torge, M.; Ulrich, S.; Ziebert, C.; Bruns, M.; Seifert, H.J.; Pfleging, W.

    2011-01-01

    It is expected that cathodes for lithium-ion batteries (LIB) composed out of nano-composite materials lead to an increase in power density of the LIB due to large electrochemically active surface areas but cathodes made of lithium manganese oxides (Li-Mn-O) suffer from structural instabilities due to their sensitivity to the average manganese oxidation state. Therefore, thin films in the Li-Mn-O system were synthesized by non-reactive radiofrequency magnetron sputtering of a spinel lithium manganese oxide target. For the enhancement of the power density and cycle stability, large area direct laser patterning using UV-laser radiation with a wavelength of 248 nm was performed. Subsequent laser annealing processes were investigated in a second step in order to set up a spinel-like phase using 940 nm laser radiation at a temperature of 680 deg. C. The interaction processes between UV-laser radiation and the material was investigated using laser ablation inductively coupled plasma mass spectroscopy. The changes in phase, structure and grain shape of the thin films due to the annealing process were recorded using Raman spectroscopy, X-ray diffraction and scanning electron microscopy. The structured cathodes were cycled using standard electrolyte and a metallic lithium anode. Different surface structures were investigated and a significant increase in cycling stability was found. Surface chemistry of an as-deposited as well as an electrochemically cycled thin film was investigated via X-ray photoelectron spectroscopy.

  19. Solid Oxide Fuel Cell Cathodes. Unraveling the Relationship Between Structure, Surface Chemistry and Oxygen Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Gopalan, Srikanth [Boston Univ., MA (United States)

    2013-03-31

    In this work we have considered oxygen reduction reaction on LSM and LSCF cathode materials. In particular we have used various spectroscopic techniques to explore the surface composition, transition metal oxidation state, and the bonding environment of oxygen to understand the changes that occur to the surface during the oxygen reduction process. In a parallel study we have employed patterned cathodes of both LSM and LSCF cathodes to extract transport and kinetic parameters associated with the oxygen reduction process.

  20. Analysis of cathode materials of perovskite structure for solid oxide fuel cells, sofc s; Analisis de materiales catodicos de estructura perovskita para celdas de combustible de oxido solido, sofcs

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado F, J.; Espino V, J.; Avalos R, L. [Universidad Michoacana de San Nicolas de Hidalgo, Facultad de Ingenieria Quimica, Santiago Tapia 403, Morelia, Michoacan (Mexico)

    2015-07-01

    Fuel cells directly and efficiently convert the chemical energy of a fuel into electrical energy. Of the various types of fuel cells, the solid oxide (Sofc), combine the advantages in environmentally benign energy generation with fuel flexibility. However, the need for high operating temperatures (800 - 1000 grades C) has resulted in high costs and major challenges in relation to the compatibility the cathode materials. As a result, there have been significant efforts in the development of intermediate temperature Sofc (500 - 700 grades C). A key obstacle for operation in this temperature range is the limited activity of traditional cathode materials for electrochemical reduction oxygen. In this article, the progress of recent years is discussed in cathodes for Sofc perovskite structure (ABO{sub 3}), more efficient than the traditionally used La{sub 1-x}Sr{sub x}MnO{sub 3-δ} (LSM) or (La, Sr) CoO{sub 3}. Such is the case of mixed conductors (MIEC) double perovskite structure (A A B{sub 2}O{sub 5+δ}) using different doping elements as La, Sr, Fe, Ti, Cr, Sm, Co, Cu, Pr, Nd, Gd, dy, Mn, among others, which could improve the operational performance of existing cathode materials, promoting the development of optimized intermediate temperature Sofc designs. (Author)

  1. Highly efficient and robust cathode materials for low-temperature solid oxide fuel cells: PrBa0.5Sr0.5Co(2-x)Fe(x)O(5+δ).

    Science.gov (United States)

    Choi, Sihyuk; Yoo, Seonyoung; Kim, Jiyoun; Park, Seonhye; Jun, Areum; Sengodan, Sivaprakash; Kim, Junyoung; Shin, Jeeyoung; Jeong, Hu Young; Choi, YongMan; Kim, Guntae; Liu, Meilin

    2013-01-01

    Solid oxide fuel cells (SOFC) are the cleanest, most efficient, and cost-effective option for direct conversion to electricity of a wide variety of fuels. While significant progress has been made in anode materials with enhanced tolerance to coking and contaminant poisoning, cathodic polarization still contributes considerably to energy loss, more so at lower operating temperatures. Here we report a synergistic effect of co-doping in a cation-ordered double-perovskite material, PrBa0.5Sr0.5Co(2-x)Fe(x)O(5+δ), which has created pore channels that dramatically enhance oxygen ion diffusion and surface oxygen exchange while maintaining excellent compatibility and stability under operating conditions. Test cells based on these cathode materials demonstrate peak power densities ~2.2 W cm(-2) at 600°C, representing an important step toward commercially viable SOFC technologies.

  2. Highly efficient and robust cathode materials for low-temperature solid oxide fuel cells: PrBa0.5Sr0.5Co2−xFexO5+δ

    Science.gov (United States)

    Choi, Sihyuk; Yoo, Seonyoung; Kim, Jiyoun; Park, Seonhye; Jun, Areum; Sengodan, Sivaprakash; Kim, Junyoung; Shin, Jeeyoung; Jeong, Hu Young; Choi, YongMan; Kim, Guntae; Liu, Meilin

    2013-01-01

    Solid oxide fuel cells (SOFC) are the cleanest, most efficient, and cost-effective option for direct conversion to electricity of a wide variety of fuels. While significant progress has been made in anode materials with enhanced tolerance to coking and contaminant poisoning, cathodic polarization still contributes considerably to energy loss, more so at lower operating temperatures. Here we report a synergistic effect of co-doping in a cation-ordered double-perovskite material, PrBa0.5Sr0.5Co2−xFexO5+δ, which has created pore channels that dramatically enhance oxygen ion diffusion and surface oxygen exchange while maintaining excellent compatibility and stability under operating conditions. Test cells based on these cathode materials demonstrate peak power densities ~2.2 W cm−2 at 600°C, representing an important step toward commercially viable SOFC technologies. PMID:23945630

  3. Bismuth-doped La1.75Sr0.25NiO4+: δ as a novel cathode material for solid oxide fuel cells

    NARCIS (Netherlands)

    Zhu, Zhesheng; Li, Mei; Xia, Changrong; Bouwmeester, Henny J.M.

    2017-01-01

    Bismuth has been doped into mixed ionic-electronic conducting La1.75Sr0.25NiO4+δ (LSN) with the 2D K2NiF4-type structure to evaluate its influence on various properties of the host material, which include its potential use as a SOFC cathode. X-ray powder diffraction indicates that LSN retains its

  4. Wire winding increases lifetime of oxide coated cathodes

    Science.gov (United States)

    Kerslake, W.; Vargo, D.

    1965-01-01

    Refractory-metal heater base wound with a thin refractory metal wire increases the longevity of oxide-coated cathodes. The wire-wound unit is impregnated with the required thickness of metal oxide. This cathode is useful in magnetohydrodynamic systems and in electron tubes.

  5. Li- and Mn-Rich Cathode Materials: Challenges to Commercialization

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jianming [Energy and Environmental Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Myeong, Seungjun [School of Energy and Chemical Engineering, Green Energy Materials Development Center, Ulsan National Institute of Science and Technology (UNIST), Korea 689-798; Cho, Woongrae [School of Energy and Chemical Engineering, Green Energy Materials Development Center, Ulsan National Institute of Science and Technology (UNIST), Korea 689-798; Yan, Pengfei [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Xiao, Jie [Energy and Environmental Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Wang, Chongmin [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Cho, Jaephil [School of Energy and Chemical Engineering, Green Energy Materials Development Center, Ulsan National Institute of Science and Technology (UNIST), Korea 689-798; Zhang, Ji-Guang [Energy and Environmental Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA

    2016-12-14

    The lithium- and manganese-rich (LMR) layered structure cathode exhibit one of the highest specific energy (~900 Wh kg-1) among all the cathode materials. However, the practical applications of LMR cathodes are still hindered by several significant challenges including voltage fade, large initial capacity loss, poor rate capability and limited cycle life. Herein, we review the recent progresses and understandings on the application of LMR cathode materials from practical point of view. Several key parameters of LMR cathodes that affect the LMR/graphite full cell operation are systematically analysed. These factors include the first cycle capacity loss, voltage fade, powder tap density, electrode density of LMR based cathode etc. New approaches to minimize the detrimental effect of these factors are highlighted in this work. We also provided the perspectives for the future research on LMR cathode materials, focusing on addressing the fundamental problems of LMR cathodes while always keeping practical considerations in mind.

  6. Electrical, thermal and electrochemical properties of SmBa_1_−_xSr_xCo_2O_5_+_δ cathode materials for intermediate-temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Subardi, Adi; Chen, Ching-Cheng; Cheng, Meng-Hsien; Chang, Wen-Ku; Fu, Yen-Pei

    2016-01-01

    The effects of Sr doping on the Ba-site of SmBaCo_2O_5_+_δ in term of structure characteristics, thermal expansion coefficients (TECs), electrical properties and electrochemical performance have been investigated as cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The TECs of SBSC-based cathodes are calculated from 19.8 − 20.5 × 10"−"6 K"−"1 in the temperature range of 100–800 °C, and the TEC values decrease with increasing Sr content. The oxygen content and the average oxidation state of cobalt increase with increasing Sr content determined by the X-ray photoelectron spectroscopy (XPS) and Thermogravimetry analysis (TGA) results. At a given temperature, the electrical conductivity values are in the order as follows: SBSC55 > SBSC73 > SBSC91. This behavior might be due to the increase in electronic hole. The electrical conductivities of SBSC55 at 600 °C are distributed in the range of 660 S/cm of p(O_2) = 0.01 atm to 1168 S/cm of p(O_2) = 0.21 atm, indicating that the cathode can endure reducing atmosphere. SBSC55 with high electrical conductivity in p(O_2) = 0.01 atm is ascribed to SBSC55 with stable double-perovskite structure at such low oxygen partial pressure. The SBSC55 cathode showed the highest power density of 304 mW/cm"2 at operating temperature of 700 °C. Based on the electrochemical properties, SBSC55 is a potential cathode for IT-SOFCs.

  7. Crystalline structure and microstructural characteristics of the cathode/electrolyte solid oxide half-cells

    International Nuclear Information System (INIS)

    Chiba, Rubens; Vargas, Reinaldo Azevedo; Andreoli, Marco; Santoro, Thais Aranha de Barros; Seo, Emilia Satoshi Miyamaru

    2009-01-01

    The solid oxide fuel cell (SOFC) is an electrochemical device generating of electric energy, constituted of cathode, electrolyte and anode; that together they form a unity cell. The study of the solid oxide half-cells consisting of cathode and electrolyte it is very important, in way that is the responsible interface for the reduction reaction of the oxygen. These half-cells are ceramic materials constituted of strontium-doped lanthanum manganite (LSM) for the cathode and yttria-stabilized zirconia (YSZ) for the electrolyte. In this work, two solid oxide half-cells have been manufactured, one constituted of LSM cathode thin film on YSZ electrolyte substrate (LSM - YSZ half-cell), and another constituted of LSM cathode and LSM/YSZ composite cathode thin films on YSZ electrolyte substrate (LSM - LSM/YSZ - YSZ half cell). The cathode/electrolyte solid oxide half-cells were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results have been presented with good adherence between cathode and electrolyte and, LSM and YSZ phases were identified. (author)

  8. Ab initio study of vacancy formation in cubic LaMnO{sub 3} and SmCoO{sub 3} as cathode materials in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Emilia; Aparicio-Anglès, Xavier [Department of Chemistry, University College London, London WC1H 0AJ (United Kingdom); Leeuw, Nora H. de, E-mail: deleeuwn@cardiff.ac.uk [Department of Chemistry, University College London, London WC1H 0AJ (United Kingdom); School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT (United Kingdom)

    2016-07-07

    Doped LaMnO{sub 3} and SmCoO{sub 3} are important solid oxide fuel cell cathode materials. The main difference between these two perovskites is that SmCoO{sub 3} has proven to be a more efficient cathode material than LaMnO{sub 3} at lower temperatures. In order to explain the difference in efficiency, we need to gain insight into the materials’ properties at the atomic level. However, while LaMnO{sub 3} has been widely studied, ab initio studies on SmCoO{sub 3} are rare. Hence, in this paper, we perform a comparative DFT + U study of the structural, electronic, and magnetic properties of these two perovskites. To that end, we first determined a suitable Hubbard parameter for the Co d–electrons to obtain a proper description of SmCoO{sub 3} that fully agrees with the available experimental data. We next evaluated the impact of oxygen and cation vacancies on the geometry, electronic, and magnetic properties. Oxygen vacancies strongly alter the electronic and magnetic structures of SmCoO{sub 3}, but barely affect LaMnO{sub 3}. However, due to their high formation energy, their concentrations in the material are very low and need to be induced by doping. Studying the cation vacancy concentration showed that the formation of cation vacancies is less energetically favorable than oxygen vacancies and would thus not markedly influence the performance of the cathode.

  9. Lithium nickel cobalt manganese oxide synthesized using alkali chloride flux: morphology and performance as a cathode material for lithium ion batteries.

    Science.gov (United States)

    Kim, Yongseon

    2012-05-01

    Li(Ni(0.8)Co(0.1)Mn(0.1))O(2) (NCM811) was synthesized using alkali chlorides as a flux and the performance as a cathode material for lithium ion batteries was examined. Primary particles of the powder were segregated and grown separately in the presence of liquid state fluxes, which induced each particle to be composed of one primary particle with well-developed facet planes, not the shape of agglomerates as appears with commercial NCMs. The new NCM showed far less gas emission during high temperature storage at charged states, and higher volumetric capacity thanks to its high bulk density. The material is expected to provide optimal performances for pouch type lithium ion batteries, which require high volumetric capacity and are vulnerable to deformation caused by gas generation from the electrode materials.

  10. Fibrous polyaniline@manganese oxide nanocomposites as supercapacitor electrode materials and cathode catalysts for improved power production in microbial fuel cells.

    Science.gov (United States)

    Ansari, Sajid Ali; Parveen, Nazish; Han, Thi Hiep; Ansari, Mohammad Omaish; Cho, Moo Hwan

    2016-04-07

    Fibrous Pani-MnO2 nanocomposite were prepared using a one-step and scalable in situ chemical oxidative polymerization method. The formation, structural and morphological properties were investigated using a range of characterization techniques. The electrochemical capacitive behavior of the fibrous Pani-MnO2 nanocomposite was examined by cyclic voltammetry and galvanostatic charge-discharge measurements using a three-electrode experimental setup in an aqueous electrolyte. The fibrous Pani-MnO2 nanocomposite achieved high capacitance (525 F g(-1) at a current density of 2 A g(-1)) and excellent cycling stability of 76.9% after 1000 cycles at 10 A g(-1). Furthermore, the microbial fuel cell constructed with the fibrous Pani-MnO2 cathode catalyst showed an improved power density of 0.0588 W m(-2), which was higher than that of pure Pani and carbon paper, respectively. The improved electrochemical supercapacitive performance and cathode catalyst performance in microbial fuel cells were attributed mainly to the synergistic effect of Pani and MnO2 in fibrous Pani-MnO2, which provides high surface area for the electrode/electrolyte contact as well as electronic conductive channels and exhibits pseudocapacitance behavior.

  11. Molten carbonate fuel cell cathode with mixed oxide coating

    Science.gov (United States)

    Hilmi, Abdelkader; Yuh, Chao-Yi

    2013-05-07

    A molten carbonate fuel cell cathode having a cathode body and a coating of a mixed oxygen ion conductor materials. The mixed oxygen ion conductor materials are formed from ceria or doped ceria, such as gadolinium doped ceria or yttrium doped ceria. The coating is deposited on the cathode body using a sol-gel process, which utilizes as precursors organometallic compounds, organic and inorganic salts, hydroxides or alkoxides and which uses as the solvent water, organic solvent or a mixture of same.

  12. Cobalt-free perovskite Pr_0_._5Sr_0_._5Fe_1_−_xCu_xO_3_−_δ (PSFC) as a cathode material for intermediate temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Moura, Caroline G.; Grilo, João Paulo de F.; Macedo, Daniel A.; Cesário, Moisés R.; Fagg, Duncan Paul; Nascimento, Rubens M.

    2016-01-01

    PSFC (Pr_0_._5Sr_0_._5Fe_1_−_xCu_xO_3_−_δ) is a new perovskite-type oxide that has gained considerable attention as cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs), due to its high mixed ionic-electronic conductivity below 800 °C. In this work, PSFC (Pr_0_._5Sr_0_._5Fe_1_−_xCu_xO_3_−_δ, x = 0.2 and 0.4) powders were synthesized by the citrate method and structurally characterized by X-ray diffractometry. Screen-printed cathodes were sintered at 1050 °C and electrochemically characterized by impedance spectroscopy at 600–800 °C in pure oxygen. The area specific resistances (ASR) of the Pr_0_._5Sr_0_._5Fe_0_._8Cu_0_._2O_3_−_δ material are shown to be competitive with typical values reported for cobalt-based cathodes in the measured temperature range, while, importantly, offering a significantly lower activation energy, 0.62 eV. The thermal expansion coefficients of these Co-free cathodes are in the range of 13–15 × 10"−"6 °C"−"1, in a temperature range 200–650 °C, demonstrating a good thermal compatibility with gadolinia doped ceria (CGO) electrolytes. - Highlights: • Cobalt-free Pr_0_._5Sr_0_._5Fe_1_−_xCu_xO_3_−_δ (PSFC) cathodes successfully prepared by the citrate method. • PSFC cathodes are thermally compatible with CGO electrolytes. • Pr_0_._5Sr_0_._5Fe_0_._8Cu_0_._2O_3_−_δ presents competitive area specific resistances of low activation energy, 0.62 eV.

  13. Properties of cathode materials in alkaline cells

    International Nuclear Information System (INIS)

    Salkind, A.J.; McBreen, J.; Freeman, R.; Parkhurst, W.A.

    1985-01-01

    Conventional and new cathode materials in primary and secondary alkaline cells were investigated for stability, structure, electrochemical reversibility and efficiency. Included were various forms of AgO for reserve-type silver-zinc batteries, a new material - AgNiO/sub 2/ - and several nickel electrodes for nickel-cadmium and nickel-hydrogen cells for aerospace applications. A comparative study was made of the stability of electroformed and chemically prepared AgO. Stability was correlated with impurities detected by XPS and SAM. After the first discharge AgNiO/sub 2/ can be recharged to the monovalent level. The discharge product is predominantly silver. Plastic-bonded nickel electrodes display a second plateau on discharge. Additions of Co(OH)/sub 2/ largely eliminate this

  14. Reduced graphene oxide supported highly porous V2O5 spheres as a high-power cathode material for lithium ion batteries.

    Science.gov (United States)

    Rui, Xianhong; Zhu, Jixin; Sim, Daohao; Xu, Chen; Zeng, Yi; Hng, Huey Hoon; Lim, Tuti Mariana; Yan, Qingyu

    2011-11-01

    Reduced graphene oxide (rGO) supported highly porous polycrystalline V(2)O(5) spheres (V(2)O(5)/rGO) were prepared by using a solvothermal approach followed by an annealing process. Initially, reduced vanadium oxide (rVO) nanoparticles with sizes in the range of 10-50 nm were formed through heterogeneous nucleation on rGO sheets during the solvothermal process. These rVO nanoparticles were oxidized to V(2)O(5) after the annealing process in air at 350 °C and assembled into polycrystalline porous spheres with sizes of 200-800 nm. The weight ratio between the rGO and V(2)O(5) is tunable by changing the weight ratio of the precursors, which in turn affects the morphology of V(2)O(5)/rGO composites. The V(2)O(5)/rGO composites display superior cathode performances with highly reversible specific capacities, good cycling stabilities and excellent rate capabilities (e.g. 102 mA h g(-1) at 19 C).

  15. The cooperative electrochemical oxidation of chlorophenols in anode-cathode compartments

    International Nuclear Information System (INIS)

    Wang Hui; Wang Jianlong

    2008-01-01

    By using a self-made carbon/polytetrafluoroethylene (C/PTFE) O 2 -fed as the cathode and Ti/IrO 2 /RuO 2 as the anode, the degradation of three organic compounds (phenol, 4-chlorophenol, and 2,4-dichlorophenol) was investigated in the diaphragm (with terylene as diaphragm material) electrolysis device by electrochemical oxidation process. The result indicated that the concentration of hydrogen peroxide (H 2 O 2 ) was 8.3 mg/L, and hydroxyl radical (HO·) was determined in the cathodic compartment by electron spin resonance spectrum (ESR). The removal efficiency for organic compounds reached about 90% after 120 min, conforming to the sequence of phenol, 4-chlorophenol, and 2,4-dichlorophenol. And the dechlorination degree of 4-chlorophenol exceeded 90% after 80 min. For H 2 O 2 , HO· existed in the catholyte and reduction dechlorination at the cathode, the mineralization of organics in the cathodic compartment was better than that in the anodic compartment. The degradation of organics was supposed to be cooperative oxidation by direct or indirect electrochemical oxidation at the anode and H 2 O 2 , HO· produced by oxygen reduction at the cathode. High-performance liquid chromatography (HPLC) allowed identifying phenol as the dechlorination product of 4-chlorophenol in the cathodic compartment, and hydroquinone, 4-chlorocatechol, benzoquinone, maleic, fumaric, oxalic, and formic acids as the main oxidation intermediates in the cathodic and anodic compartments. A reaction scheme involving all these intermediates was proposed

  16. Characterization of cathode materials SrCoO3 and La0,2Sr0,8CoO3 for use in solid oxide fuel cells (SOFC)

    International Nuclear Information System (INIS)

    Galvao, G.O.; Aquino, F.M; Silva, R.M.; Medeiros, I.D.M. de

    2016-01-01

    Mixed oxide ceramics with chemical structure of ABO_3 type are promising candidates for cathodes of solid oxide fuel cells (SOFC) for performing well on the electrical conductivity and thermal stability. Various methods of preparation have been studied and used for the synthesis of these materials. In this study, SrCoO_3 and La_0_,_2Sr_0_,_8CoO_3 perovskites were synthesized using gelatin as directing agent with the purpose of producing homogeneous and porous particles. The powders obtained at 350 ° C / 2 h were calcined at 600, 800 and 1000 ° C for 4 hours and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that gelatin is a good polymerizing agent for metal ions as the material showed characteristic peaks of perovskite, with good porosity and uniformity. Furthermore, the method of synthesis employed has advantages related to cost and toxicity, which are very low. (author)

  17. An ionic-liquid-assisted approach to synthesize a reduced graphene oxide loading iron-based fluoride as a cathode material for sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Miaoling; Wang, Xianyou, E-mail: wxianyou@yahoo.com; Wei, Shuangying; Shen, Yongqiang; Hu, Hai

    2016-06-15

    A reduced graphene oxide loading iron-based fluoride (abbreviated as Fe{sub 2}F{sub 5}·H{sub 2}O/rGO) as a cathode material for sodium ion batteries (SIBs) has been successfully prepared by an ionic-liquid-assisted route. The morphology, structure, physicochemical properties and electrochemical performance are characterized by X-ray powder diffraction (XRD), Rietveld refinement of XRD pattern, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical tests. The XRD result shows that the crystal structure of the as-prepared sample can be indexed to the cubic Fd-3m space group and the lattice parameter is as follow: a = 1.04029 nm and V = 1.12581 nm{sup 3}. Moreover, the SEM and TEM images reveal that the as-prepared rGO has a rough wavy structure and flexural paper-like morphology, and numerous Fe{sub 2}F{sub 5}·H{sub 2}O particles are firmly adhered on the surface of the rGO to form an uniform Fe{sub 2}F{sub 5}·H{sub 2}O/rGO composite. Electrochemical tests show that the initial discharge capacity of Fe{sub 2}F{sub 5}·H{sub 2}O/rGO sample is 248.7 mAh g{sup −1} and the corresponding charging capacity up to 229.7 mAh g{sup −1} at a rate of 20 mA g{sup −1}. Especially, the Fe{sub 2}F{sub 5}·H{sub 2}O/rGO possesses good cycling stability, and it can deliver a discharge capacity of 164.2 mAh g{sup −1} at the 100th cycle. Besides, the rate capability tests show that a stable high capacity of 186.0 mAh g{sup −1} can be resumed when the current rate returns to 20 mA g{sup −1} after 20 cycles. - - Highlights: • The Fe{sub 2}F{sub 5}·H{sub 2}O/rGO has been successfully prepared by an ionic-liquid-assisted method. • The paper-like rGO could be obtained by a green hydrothermal method. • Numerous Fe{sub 2}F{sub 5}·H{sub 2}O particles are adhered firmly on the surface of the paper-like rGO. • The Fe{sub 2}F{sub 5}·H{sub 2}O/rGO shows excellent cycling stability and rate capability.

  18. Development of cathode material for lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Rustam Mukhtaruly Turganaly

    2014-08-01

    Full Text Available The electrochemical characteristics of the cathode material coated with carbon layer has been developed. Various carbon coating methods. There  has been carried out a comparative electrochemical analysis of the coated and uncoated with carbon cathode material

  19. Application of scandium oxide in an electron emission material

    International Nuclear Information System (INIS)

    Suqiu, Y.; Zhizheng, Z.; Yongde, W.

    1985-01-01

    Modern microwave devices impose a number of harsh requirements on the cathodes. For instance, they require cathodes having low working temperature, high emissive current density, slow evaporation rate of the emissive-active material, long lifetime, quick heating and so on. The commercial B-cathode is no longer able to meet these requirements completely. A scandate cathode may be a promising one for use in these devices. Adding rare-earth elements in the electron emission material has been reported in many papers. Based on a B-cathode we add a little amount of scandium oxide (about 3%) into emission material to manufacture a scandate cathode. The emission property of such a cathode has been improved greatly. If the composition is controlled correctly, the emission level of such a cathode may be five times more as high as the B-cathode

  20. Iron phosphate materials as cathodes for lithium batteries

    CERN Document Server

    Prosini, Pier Paolo

    2011-01-01

    ""Iron Phosphate Materials as Cathodes for Lithium Batteries"" describes the synthesis and the chemical-physical characteristics of iron phosphates, and presents methods of making LiFePO4 a suitable cathode material for lithium-ion batteries. The author studies carbon's ability to increase conductivity and to decrease material grain size, as well as investigating the electrochemical behaviour of the materials obtained. ""Iron Phosphate Materials as Cathodes for Lithium Batteries"" also proposes a model to explain lithium insertion/extraction in LiFePO4 and to predict voltage profiles at variou

  1. An Aurivillius Oxide Based Cathode with Excellent CO2 Tolerance for Intermediate-Temperature Solid Oxide Fuel Cells.

    Science.gov (United States)

    Zhu, Yinlong; Zhou, Wei; Chen, Yubo; Shao, Zongping

    2016-07-25

    The Aurivillius oxide Bi2 Sr2 Nb2 MnO12-δ (BSNM) was used as a cobalt-free cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). To the best of our knowledge, the BSNM oxide is the only alkaline-earth-containing cathode material with complete CO2 tolerance that has been reported thus far. BSNM not only shows favorable activity in the oxygen reduction reaction (ORR) at intermediate temperatures but also exhibits a low thermal expansion coefficient, excellent structural stability, and good chemical compatibility with the electrolyte. These features highlight the potential of the new BSNM material as a highly promising cathode material for IT-SOFCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. In situ X-ray studies of film cathodes for solid oxide fuel cells

    International Nuclear Information System (INIS)

    Fuoss, Paul; Chang, Kee-Chul; You, Hoydoo

    2013-01-01

    Highlights: •Synchrotron X-rays are used to study in operando the structural and chemical changes of LSM and LSCF film cathodes during half-cell operations. •A-site and B-site cations actively segregate or desegregate on the changes of temperature, pO 2 , and electrochemical potential. •Chemical lattice expansions show that oxygen-cathode interface is the primary source of rate-limiting processes. •The surface and subsurface of the LSM and LSCF films have different oxidation-states due to vacancy concentration changes. •Liquid-phase infiltration and coarsening processes of cathode materials into porous YSZ electrolyte backbone were monitored by USAXS. -- Abstract: Synchrotron-based X-ray techniques have been used to study in situ the structural and chemical changes of film cathodes during half-cell operations. The X-ray techniques used include X-ray reflectivity (XR), total-reflection X-ray fluorescence (TXRF), high-resolution diffraction (HRD), ultra-small angle X-ray scattering (USAXS). The epitaxial thin film model cathodes for XR, TXRF, and HRD measurements are made by pulse laser deposition and porous film cathodes for USAX measurements are made by screen printing technique. The experimental results reviewed here include A-site and B-site segregations, lattice expansion, oxidation-state changes during cell operations and liquid-phase infiltration and coarsening of cathode to electrolyte backbone

  3. A Novel Cathode Material for Cathodic Dehalogenation of 1,1-Dibromo Cyclopropane Derivatives.

    Science.gov (United States)

    Gütz, Christoph; Selt, Maximilian; Bänziger, Markus; Bucher, Christoph; Römelt, Christina; Hecken, Nadine; Gallou, Fabrice; Galvão, Tomás R; Waldvogel, Siegfried R

    2015-09-28

    Leaded bronze turned out to be an excellent cathode material for the dehalogenation reaction of cyclopropanes without affecting the strained molecular entity. With this particular alloy, beneficial properties of lead cathodes are conserved, whereas the corrosion of cathode is efficiently suppressed. The solvent in the electrolyte determines whether a complete debromination reaction is achieved or if the process can be selectively stopped at the monobromo cyclopropane intermediate. The electroorganic conversion tolerates a variety of functional groups and can be conducted at rather complex substrates like cyclosporine A. This approach allows the sustainable preparation of cyclopropane derivatives. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Tailored Core Shell Cathode Powders for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Swartz, Scott [NexTech Materials, Ltd.,Lewis Center, OH (United States)

    2015-03-23

    In this Phase I SBIR project, a “core-shell” composite cathode approach was evaluated for improving SOFC performance and reducing degradation of lanthanum strontium cobalt ferrite (LSCF) cathode materials, following previous successful demonstrations of infiltration approaches for achieving the same goals. The intent was to establish core-shell cathode powders that enabled high performance to be obtained with “drop-in” process capability for SOFC manufacturing (i.e., rather than adding an infiltration step to the SOFC manufacturing process). Milling, precipitation and hetero-coagulation methods were evaluated for making core-shell composite cathode powders comprised of coarse LSCF “core” particles and nanoscale “shell” particles of lanthanum strontium manganite (LSM) or praseodymium strontium manganite (PSM). Precipitation and hetero-coagulation methods were successful for obtaining the targeted core-shell morphology, although perfect coverage of the LSCF core particles by the LSM and PSM particles was not obtained. Electrochemical characterization of core-shell cathode powders and conventional (baseline) cathode powders was performed via electrochemical impedance spectroscopy (EIS) half-cell measurements and single-cell SOFC testing. Reliable EIS testing methods were established, which enabled comparative area-specific resistance measurements to be obtained. A single-cell SOFC testing approach also was established that enabled cathode resistance to be separated from overall cell resistance, and for cathode degradation to be separated from overall cell degradation. The results of these EIS and SOFC tests conclusively determined that the core-shell cathode powders resulted in significant lowering of performance, compared to the baseline cathodes. Based on the results of this project, it was concluded that the core-shell cathode approach did not warrant further investigation.

  5. Chemically stable perovskites as cathode materials for solid oxide fuel cells: La-doped Ba0.5Sr0.5Co0.8Fe0.2O(3-δ).

    Science.gov (United States)

    Kim, Junyoung; Choi, Sihyuk; Jun, Areum; Jeong, Hu Young; Shin, Jeeyoung; Kim, Guntae

    2014-06-01

    Ba0.5Sr0.5Co0.8Fe0.2O(3-δ) (BSCF) has won tremendous attention as a cathode material for intermediate-temperature solid-oxide fuel cells (IT-SOFC) on the basis of its fast oxygen-ion transport properties. Nevertheless, wide application of BSCF is impeded by its phase instabilities at intermediate temperature. Here we report on a chemically stable SOFC cathode material, La0.5Ba0.25Sr0.25Co0.8Fe0.2O(3-δ) (LBSCF), prepared by strategic approaches using the Goldschmidt tolerance factor. The tolerance factors of LBSCF and BSCF indicate that the structure of the former has a smaller deformation of cubic symmetry than that of the latter. The electrical property and electrochemical performance of LBSCF are improved compared with those of BSCF. LBSCF also shows excellent chemical stability under air, a CO2-containg atmosphere, and low oxygen partial pressure while BSCF decomposed under the same conditions. Together with this excellent stability, LBSCF shows a power density of 0.81 W cm(-2) after 100 h, whereas 25 % degradation for BSCF is observed after 100 h. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. On the Defect Chemistry, Electrical Properties and Electrochemical Performances As Solid Oxide Fuel Cell Cathode Materials of New La-(Sr/Vac)-Co-Ti-O Perovskites

    DEFF Research Database (Denmark)

    García-Alvarado, Flaviano; Gómez-Pérez, Alejandro; Pérez-Flores, Juan Carlos

    2015-01-01

    Perovskite-type oxides are well known materials that have been proposed as electrodes and electrolytes for solid oxide fuel cells (SOFCs). The structure, which is referred to the ABO3 stoichiometry, can accommodate many different transition metal ions in the B-site; its electronic conductivity...... materials with valuable properties for SOFCs. We have analysed the effect of La3+ by Sr2+ substitution and vacancies creation in several double perovskites, La2MTiO6 (M = Co, Ni, Cu). Defect chemistry and electrical behavior have been investigated in order to unveil the nature of charge carriers....... Electrochemical performances have been assessed through polarization resistance measurements. In this communication we present the results regarding La2SrTiO6 perovskites. La/Sr substitution in La2-xSrxCoTiO6-δ produces Co2+ to Co3+ oxidation while vacancies in La2-xCoTiO6-δ yield Co2+ oxidation for low A...

  7. Battery designs with high capacity anode materials and cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Masarapu, Charan; Anguchamy, Yogesh Kumar; Han, Yongbong; Deng, Haixia; Kumar, Sujeet; Lopez, Herman A.

    2017-10-03

    Improved high energy capacity designs for lithium ion batteries are described that take advantage of the properties of high specific capacity anode active compositions and high specific capacity cathode active compositions. In particular, specific electrode designs provide for achieving very high energy densities. Furthermore, the complex behavior of the active materials is used advantageously in a radical electrode balancing design that significantly reduced wasted electrode capacity in either electrode when cycling under realistic conditions of moderate to high discharge rates and/or over a reduced depth of discharge.

  8. Graphenated tantalum(IV) oxide and poly(4-styrene sulphonic acid)-doped polyaniline nanocomposite as cathode material in an electrochemical capacitor

    International Nuclear Information System (INIS)

    Njomo, Njagi; Waryo, Tesfaye; Masikini, Milua; Ikpo, Chinwe O.; Mailu, Stephen; Tovide, Oluwakemi; Ross, Natasha; Williams, Avril; Matinise, Nolubabalo; Sunday, Christopher E.; Mayedwa, Noluthando; Baker, Priscilla G.L.; Ozoemena, Kenneth I.; Iwuoha, Emmanuel I.

    2014-01-01

    Nanostructured poly(4-styrene sulphonic acid) and tantalum (IV) oxide-doped polyaniline nanocomposite were synthesised and their electro-conductive properties were determined. The oxide was synthesized using a modified sol-gel method and then dispersed in acidic media through sonication and entrapped in-situ into the polymeric matrix during the oxidative chemical polymerization of aniline doped with poly(4-styrene sulphonic acid). The oxides and novel polymeric nanocomposite were characterised with TEM, SEM, EDX, XRD, FTIR, UV-visible to ascertain elemental and phase composition, successful polymerization, doping, morphology and entrapment of the metal oxide nanoparticles. The electro-conductivity of the nanomaterial was interrogated using scanning electrochemical microscopy (SECM) and cyclic voltammetry (CV). The material was then anchored on activated graphitic carbon and used in the design of an asymmetric supercapacitor cell using 6 M KOH aqueous electrolyte. Characteristically high specific capacitance values of 318.4 F/g with a corresponding energy and power densities of 1.57 kWh/kg and 0.435 kW/kg, respectively, were demonstrated. The cell also showed high coulombic efficiency of 94.9% with a long cycle life and good cycle stability making the nanomaterial suitable for constructing supercapacitor cell electrodes

  9. Solid oxide fuel cells having porous cathodes infiltrated with oxygen-reducing catalysts

    Science.gov (United States)

    Liu, Meilin; Liu, Ze; Liu, Mingfei; Nie, Lifang; Mebane, David Spencer; Wilson, Lane Curtis; Surdoval, Wayne

    2014-08-12

    Solid-oxide fuel cells include an electrolyte and an anode electrically coupled to a first surface of the electrolyte. A cathode is provided, which is electrically coupled to a second surface of the electrolyte. The cathode includes a porous backbone having a porosity in a range from about 20% to about 70%. The porous backbone contains a mixed ionic-electronic conductor (MIEC) of a first material infiltrated with an oxygen-reducing catalyst of a second material different from the first material.

  10. The base metal of the oxide-coated cathode

    International Nuclear Information System (INIS)

    Poret, F.; Roquais, J.M.

    2005-01-01

    The oxide-coated cathode has been the most widely used electron emitter in vacuum electronic devices. From one manufacturing company to another the emissive oxide is either a double-Ba, Sr-or a triple-Ba, Sr, Ca-oxide, having always the same respective compositions. Conversely, the base metal composition is very often proprietary because of its importance in the cathode emission performances. The present paper aims at explaining the operation of the base metal through a review. After a brief introduction, the notion of activator is detailed along with their diffusivities and their associated interfacial compounds. Then, the different cathode life models are described prior to few comments on the composition choice of a base metal. Finally, the specificities of the RCA/Thomson 'bimetal' base metal are presented with a discussion on the optimized composition choice illustrated by a long-term life-test of five different melts

  11. Study of NiO cathode modified by rare earth oxide additive for MCFC by electrochemical impedance spectroscopy

    International Nuclear Information System (INIS)

    Huang Bo; Chen Gang; Li Fei; Yu Qingchun; Hu Keao

    2004-01-01

    The preparation and subsequent oxidation of nickel cathodes modified by impregnation with rare earth oxide were evaluated by surface and bulk analysis. The electrochemical behaviors of rare earth oxide impregnated nickel oxide cathodes were also evaluated in a molten 62 mol% Li 2 CO 3 +38 mol% K 2 CO 3 eutectic at 650 deg. C by electrochemical impedance spectroscopy (EIS) as a function of rare earth oxide content and immersion time. The rare earth oxide-impregnated nickel cathodes show almost the similar porosity, pore size, and morphology to the reference nickel cathode. The stability tests of rare earth oxide-impregnated nickel oxide cathodes show that the rare earth oxide additive can dramatically reduce the solubility of nickel oxide in a eutectic carbonate mixture under the standard cathode gas condition. The impedance response of all cathode materials at different immersion time is characterized by the presence of depressed semicircles in the high frequency range changing over into the lines with the angles of which observed with the real axis differing 45 deg. or 90 deg. in the low frequency range. The experimental Nyquist plots can be well analyzed theoretically with a modified model based on the well-known Randles-Ershler equivalent circuit model. In the new model, the double layer capacity (C d ) is replaced by the parallel combination of C d and b/ω; therefore, this circuit is modified to be the parallel combination of (C d ), b/ω, and the charge transfer resistance (R ct ) based on the Randles-Ershler equivalent circuit, to take into consideration both the non-uniformity of electric field at the electrode/electrolyte interface owing to the roughness of electrode surface, and the variety of relaxation times with adsorbed species on the electrode surface. The impedance spectra for all cathode materials show important variations during the 200 h of immersion. The incorporation of lithium in its structure and the low dissolution of nickel oxide and rare

  12. Cobalt-free cathode material SrFe{sub 0.9}Nb{sub 0.1}O{sub 3-{delta}} for intermediate-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Qingjun [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130012 (China); College of Science, Civil Aviation University of China, Tianjin 300300 (China); Zhang, Leilei; He, Tianmin [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130012 (China)

    2010-02-15

    A cobalt-free cubic perovskite oxide, SrFe{sub 0.9}Nb{sub 0.1}O{sub 3-{delta}} (SFN) was investigated as a cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). XRD results showed that SFN cathode was chemically compatible with the electrolyte Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9} (SDC) for temperatures up to 1050 C. The electrical conductivity of SFN sample reached 34-70 S cm{sup -1} in the commonly operated temperatures of IT-SOFCs (600-800 C). The area specific resistance was 0.138 {omega} cm{sup 2} for SFN cathode on SDC electrolyte at 750 C. A maximum power density of 407 mW cm{sup -2} was obtained at 800 C for single-cell with 300 {mu}m thick SDC electrolyte and SFN cathode. (author)

  13. Oxide materials as positive electrodes of lithium-ion batteries

    International Nuclear Information System (INIS)

    Makhonina, Elena V; Pervov, Vladislav S; Dubasova, Valeriya S

    2004-01-01

    The published data on oxide materials as positive electrodes for lithium-ion batteries are described systematically. The mechanisms of structural changes in cathode materials occurring during the operation of lithium-ion batteries and the problems concerned with their selection are discussed. Modern trends in optimising cathode materials and lithium-ion batteries on the whole are considered.

  14. The cathode material for a plasma-arc heater

    Science.gov (United States)

    Yelyutin, A. V.; Berlin, I. K.; Averyanov, V. V.; Kadyshevskii, V. S.; Savchenko, A. A.; Putintseva, R. G.

    1983-11-01

    The cathode of a plasma arc heater experiences a large thermal load. The temperature of its working surface, which is in contact with the plasma, reaches high values, as a result of which the electrode material is subject to erosion. Refractory metals are usually employed for the cathode material, but because of the severe erosion do not usually have a long working life. The most important electrophysical characteristic of the electrode is the electron work function. The use of materials with a low electron work function allows a decrease in the heat flow to the cathode, and this leads to an increase in its erosion resistance and working life. The electroerosion of certain materials employed for the cathode in an electric arc plasma generator in the process of reduction smelting of refractory metals was studied.

  15. Lanthanum Manganate Based Cathodes for Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Jørgensen, Mette Juhl

    Composite cathodes for solid oxide fuel cells were investigated using electrochemical impedance spectroscopy and scanning electron microscopy. The aim was to study the oxygen reduction process in the electrode in order to minimise the voltage drop in the cathode. The electrodes contained...... five processes were found to affect the impedance of LSM/YSZ composite electrodes. Two high frequency processes were ascribed to transport of oxide ions/oxygen intermediates across LSM/YSZ interfaces and through YSZ in the composite. Several competitive elementary reaction steps, which appear as one...

  16. Chromium (V) compounds as cathode material in electrochemical power sources

    Science.gov (United States)

    Delnick, F.M.; Guidotti, R.A.; McCarthy, D.K.

    A cathode for use in a thermal battery, comprising a chromium (V) compound. The preferred materials for this use are Ca/sub 5/(CrO/sub 4/)/sub 3/Cl, Ca/sub 5/(CrO/sub 4/)OH, and Cr/sub 2/O/sub 5/. The chromium (V) compound can be employed as a cathode material in ambient temperature batteries when blended with a suitably conductive filler, preferably carbon black.

  17. Modeling of thermal expansion coefficient of perovskite oxide for solid oxide fuel cell cathode

    Science.gov (United States)

    Heydari, F.; Maghsoudipour, A.; Alizadeh, M.; Khakpour, Z.; Javaheri, M.

    2015-09-01

    Artificial intelligence models have the capacity to eliminate the need for expensive experimental investigation in various areas of manufacturing processes, including the material science. This study investigates the applicability of adaptive neuro-fuzzy inference system (ANFIS) approach for modeling the performance parameters of thermal expansion coefficient (TEC) of perovskite oxide for solid oxide fuel cell cathode. Oxides (Ln = La, Nd, Sm and M = Fe, Ni, Mn) have been prepared and characterized to study the influence of the different cations on TEC. Experimental results have shown TEC decreases favorably with substitution of Nd3+ and Mn3+ ions in the lattice. Structural parameters of compounds have been determined by X-ray diffraction, and field emission scanning electron microscopy has been used for the morphological study. Comparison results indicated that the ANFIS technique could be employed successfully in modeling thermal expansion coefficient of perovskite oxide for solid oxide fuel cell cathode, and considerable savings in terms of cost and time could be obtained by using ANFIS technique.

  18. Analytical, 1-Dimensional Impedance Model of a Composite Solid Oxide Fuel Cell Cathode

    DEFF Research Database (Denmark)

    Mortensen, Jakob Egeberg; Søgaard, Martin; Jacobsen, Torben

    2014-01-01

    An analytical, 1-dimensional impedance model for a composite solid oxide fuel cell cathode is derived. It includes geometrical parameters of the cathode, e.g., the internal surface area and the electrode thickness, and also material parameters, e.g., the surface reaction rate and the vacancy...... diffusion coefficient. The model is successfully applied to a total of 42 impedance spectra, obtained in the temperature range 555°C–852°C and in the oxygen partial pressure range 0.028 atm–1.00 atm for a cathode consisting of a 50/50 wt% mixture of (La0.6Sr0.4)0.99CoO3 − δ and Ce0.9Gd0.1O1.95 − δ...... and providing both qualitative and quantitative information on the evolution of the impedance spectra of cathodes with changing parameters....

  19. A new high power thermal battery cathode material

    International Nuclear Information System (INIS)

    Faul, I.

    1986-01-01

    Smaller and lighter thermal batteries are major aims of the battery research programme at RAE Farnborough. Modern designs of thermal batteries, for use as power supplies in weapon systems, almost invariably use the Li:molten salt:FeS/sub 2/ system because of the significant increase in energy density achieved in comparison with the earlier Ca/CaCrO/sub 4/ couple. The disadvantage of the FeS/sub 2/ system is that the working cell voltage, between 1.5 and 2.0 V, is significantly lower so leading to more cells per battery than the earlier system. Further work at RAE and MSA (Britain) Ltd showed that the poor thermal stability of TiS/sub 2/ limited its use in thermal batteries, whilst the more stable V/sub 6/O/sub 13/ oxidised the electrolyte, giving poor efficiencies. However, the resulting reduced vanadium oxide material, subsequently called lithiated vanadium oxide (LVO), was found to be an excellent high voltage thermal battery cathode, being the subject of both UK and US patents. In this study both V/sub 6/O/sub 13/ made by the direct stoichiometric reaction of V/sub 2/O/sub 5/ and V and also by thermal decomposition of NH/sub 4/VO/sub 3/ under argon, have been used with equal success as the starting material for the preparation of LVO

  20. Composite cathode based on yttria stabilized bismuth oxide for low-temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Xia Changrong; Zhang Yuelan; Liu Meilin

    2003-01-01

    Composites consisting of silver and yttria stabilized bismuth oxide (YSB) have been investigated as cathodes for low-temperature honeycomb solid oxide fuel cells with stabilized zirconia as electrolytes. At 600 deg. C, the interfacial polarization resistances of a porous YSB-Ag cathode is about 0.3 Ω cm 2 , more than one order of magnitude smaller than those of other reported cathodes on stabilized zirconia. For example, the interfacial resistances of a traditional YSZ-lanthanum maganites composite cathode is about 11.4 Ω cm 2 at 600 deg. C. Impedance analysis indicated that the performance of an YSB-Ag composite cathode fired at 850 deg. C for 2 h is severely limited by gas transport due to insufficient porosity. The high performance of the YSB-Ag cathodes is very encouraging for developing honeycomb fuel cells to be operated at temperatures below 600 deg. C

  1. Preparation and Characterization of Cathode Materials for Lithium-Oxygen Batteries

    DEFF Research Database (Denmark)

    Storm, Mie Møller

    A possible future battery type is the Li-air battery which theoretically has the potential of reaching gravimetric energy densities close to those of gasoline. The Li-airbattery is discharged by the reaction of Li-ions and oxygen, drawn from the air, reacting at the battery cathode to form Li2O2....... The type of cathode material affects the battery discharge capacity and charging potential and with a carbon based cathode many questions are still unanswered. The focus of this Ph.D. project has been the synthesis of reduced graphene oxide as well as the investigation of the effect of reduced graphene...... the discharge capacity of the battery as well as the charging potential. In situ X-ray diffraction studies on carbon black cathodes in a capillary battery showed the formation of crystalline Li2O2 on the first discharge cycle, the intensity of Li2O2 on the second discharge cycle was however diminished...

  2. Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin; Preparacao de materiais catodicos para celulas a combustivel de oxido solido (SOFC) atraves do uso de gelatina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O., E-mail: rinaldo_mendesa@hotmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

    2016-07-01

    Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca{sub 3}Co{sub 4}O{sub 9}, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

  3. Impedance Modeling of Solid Oxide Fuel Cell Cathodes

    DEFF Research Database (Denmark)

    Mortensen, Jakob Egeberg; Søgaard, Martin; Jacobsen, Torben

    2010-01-01

    A 1-dimensional impedance model for a solid oxide fuel cell cathode is formulated and applied to a cathode consisting of 50/50 wt% strontium doped lanthanum cobaltite and gadolinia doped ceria. A total of 42 impedance spectra were recorded in the temperature range: 555-852°C and in the oxygen...... partial pressure range 0.028-1.00 atm. The recorded impedance spectra were successfully analyzed using the developed impedance model in the investigated temperature and oxygen partial pressure range. It is also demonstrated that the model can be used to predict how impedance spectra evolve with different...

  4. Influence of carbon black distribution on performance of oxide cathodes for Li ion batteries

    International Nuclear Information System (INIS)

    Dominko, Robert; Gaberscek, Miran; Drofenik, Jernej; Bele, Marjan; Jamnik, Janez

    2003-01-01

    The influence of carbon black content and carbon black distribution on performance of oxide-based cathodes, such as LiCoO 2 and LiMn 2 O 4 , is investigated. The electronic conductivity of oxide material/carbon black composites is compared with electrochemical characteristics of the same composites. Uniformity of carbon black distribution in cathode composites is achieved using novel coating technology in cathode preparation. In this technology, the active particles are first pretreated in a gelatin solution. The adsorbed gelatin then controls the deposition of carbon black so that carbon black particles are uniformly distributed in the final composite. The influence of various parameters, such as pH of gelatin, amount of gelatin and concentration of carbon black on the uniformity of carbon black distribution is investigated. It is shown that the conventional technology of cathode preparation yields quite non-uniform distribution of carbon black in cathode material. At the end, we demonstrate that uniformity of carbon black distribution has a crucial impact on reversible capacity, especially at high current densities

  5. High-energy cathode material for long-life and safe lithium batteries

    Science.gov (United States)

    Sun, Yang-Kook; Myung, Seung-Taek; Park, Byung-Chun; Prakash, Jai; Belharouak, Ilias; Amine, Khalil

    2009-04-01

    Layered lithium nickel-rich oxides, Li[Ni1-xMx]O2 (M=metal), have attracted significant interest as the cathode material for rechargeable lithium batteries owing to their high capacity, excellent rate capability and low cost. However, their low thermal-abuse tolerance and poor cycle life, especially at elevated temperature, prohibit their use in practical batteries. Here, we report on a concentration-gradient cathode material for rechargeable lithium batteries based on a layered lithium nickel cobalt manganese oxide. In this material, each particle has a central bulk that is rich in Ni and a Mn-rich outer layer with decreasing Ni concentration and increasing Mn and Co concentrations as the surface is approached. The former provides high capacity, whereas the latter improves the thermal stability. A half cell using our concentration-gradient cathode material achieved a high capacity of 209mAhg-1 and retained 96% of this capacity after 50 charge-discharge cycles under an aggressive test profile (55∘C between 3.0 and 4.4V). Our concentration-gradient material also showed superior performance in thermal-abuse tests compared with the bulk composition Li[Ni0.8Co0.1Mn0.1]O2 used as reference. These results suggest that our cathode material could enable production of batteries that meet the demanding performance and safety requirements of plug-in hybrid electric vehicles.

  6. Elaboration and characterisation of functionally graded cathodes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Simonet, J.; Kapelski, G.; Bouvard, D. [Laboratoire de Genie Physique et Mecanique des Materiaux, Institut National Polytechnique de Grenoble, CNRS UMR 5010, BP 46, 38042 Saint Martin d' Heres cedex (France)

    2005-07-01

    The industrial development of solid oxide fuel cells (SOFC) requires decreasing their operating temperature from 1000 deg. C to 700 deg. C while keeping acceptable mechanical and electrochemical performances. A solution consists in designing composite bulk cathodes with numerous electro-chemical reaction sites. The fabrication of such cathodes has been investigated with classical materials as lanthanum strontium manganese (LSM) and yttrium stabilized zirconia (YSZ), which is also the constitutive material of the electrolyte. A composite cathode with continuous composition gradient has been obtained by co-sedimentation of the powders in a liquid and subsequent firing. The obtained composition is investigated with Scanning Electron Microscope (SEM) and Electron Dispersive Spectrometry (EDS). It is found to be in good agreement with the prediction of a numerical model of the sedimentation process. (authors)

  7. Stability of solid oxide fuel cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.R.; Bates, J.L.; Chick, L.A. [Pacific Northwest Lab., Richland, WA (United States)

    1996-04-01

    Interconnection materials in a solid oxide fuel cell are exposed to both highly oxidizing conditions at the cathode and to highly reducing conditions at the anode. The thermal expansion characteristics of substituted lanthanum and yttrium chromite interconnect materials were evaluated by dilatometry as a function of oxygen partial pressures from 1 atm to 10{sup -18} atm, controlled using a carbon dioxide/hydrogen buffer.

  8. Cathode recovery products of oxidation of oils

    Directory of Open Access Journals (Sweden)

    М.М. Захарчук

    2009-01-01

    Full Text Available  The article provides the review of electrochemical reduction of carbonic compounds – those that are among main oxidation of oils  hydrocarbons products. The principal possibility of ketons to alcohols  reduction is proved in practice based on the experimental data . The methodical algoritm of quantative control of the catod reduction is developed, which uses the reduction-oxidizing potentiometric titration method.

  9. Functionally Graded Cathodes for Solid Oxide Fuel Cells

    International Nuclear Information System (INIS)

    Lei Yang; Ze Liu; Shizhone Wang; Jaewung Lee; Meilin Liu

    2008-01-01

    The main objective of this DOE project is to demonstrate that the performance and long-term stability of the state-of-the-art LSCF cathode can be enhanced by a catalytically active coating (e.g., LSM or SSC). We have successfully developed a methodology for reliably evaluating the intrinsic surface catalytic properties of cathode materials. One of the key components of the test cell is a dense LSCF film, which will function as the current collector for the electrode material under evaluation to eliminate the effect of ionic and electronic transport. Since it is dense, the effect of geometry would be eliminated as well. From the dependence of the electrode polarization resistance on the thickness of a dense LSCF electrode and on partial pressure of oxygen, we have confirmed that the surface catalytic activity of LSCF limits the performances of LSCF-based cathodes. Further, we have demonstrated, using test cells of different configurations, that the performance of LSCF-based electrodes can be significantly enhanced by infiltration of a thin film of LSM or SSC. In addition, the stability of LSCF-based cathodes was also improved by infiltration of LSM or SSC. While the concept feasibility of the electrode architecture is demonstrated, many details are yet to be determined. For example, it is not clear how the surface morphology, composition, and thickness of the coatings change under operating conditions over time, how these changes influence the electrochemical behavior of the cathodes, and how to control the microscopic details of the coatings in order to optimize the performance. The selection of the catalytic materials as well as the detailed microstructures of the porous LSCF and the catalyst layer may critically impact the performance of the proposed cathodes. Further, other fundamental questions still remain; it is not clear why the degradation rates of LSCF cathodes are relatively high, why a LSM coating improves the stability of LSCF cathodes, which catalysts

  10. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  11. Advanced cathode materials for high-power applications

    Science.gov (United States)

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

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

  12. Materials characterization of impregnated W and W–Ir cathodes after oxygen poisoning

    International Nuclear Information System (INIS)

    Polk, James E.; Capece, Angela M.

    2015-01-01

    Highlights: • Impregnated W and W–Ir cathodes were operated with 100 ppm of oxygen in Xe gas. • High concentrations of oxygen accelerated the formation of tungstate layers. • The W–Ir emitter exhibited less erosion and redeposition at the upstream end. • Tungsten was preferentially transported in the insert plasma of the W–Ir cathode. - Abstract: Electric thrusters use hollow cathodes as the electron source for generating the plasma discharge and for beam neutralization. These cathodes contain porous tungsten emitters impregnated with BaO material to achieve a lower surface work function and are operated with xenon propellant. Oxygen contaminants in the xenon plasma can poison the emitter surface, resulting in a higher work function and increased operating temperature. This could lead directly to cathode failure by preventing discharge ignition or could accelerate evaporation of the BaO material. Exposures over hundreds of hours to very high levels of oxygen can result in increased temperatures, oxidation of the tungsten substrate, and the formation of surface layers of barium tungstates. In this work, we present results of a cathode test in which impregnated tungsten and tungsten–iridium emitters were operated with 100 ppm of oxygen in the xenon plasma for several hundred hours. The chemical and morphological changes were studied using scanning electron microscopy, energy dispersive spectroscopy, and laser profilometry. The results provide strong evidence that high concentrations of oxygen accelerate the formation of tungstate layers in both types of emitters, a phenomenon not inherent to normal cathode operation. Deposits of pure tungsten were observed on the W–Ir emitter, indicating that tungsten is preferentially removed from the surface and transported in the insert plasma. A W–Ir cathode surface will therefore evolve to a pure W composition, eliminating the work function benefit of W–Ir. However, the W–Ir emitter exhibited less erosion

  13. Resistivity network and structural model of the oxide cathode for CRT application

    OpenAIRE

    Hashim, A. A.; Barratt, D. S.; Hassan, A. K.; Evans-Freeman, J. H.; Nabok, A.

    2006-01-01

    In this paper, the electrical properties of oxide cathode\\ud and oxide cathode plus, supplied by LG Philips Displays, have been\\ud investigated in relation to different cathode activation regimes and\\ud methods. Oxide cathode activation treatment for different durations\\ud has been investigated. The formations of the compounds associated\\ud to the diffusion of reducing elements (Mg, Al, and W) to the Ni cap surface of oxide cathode were studied by a new suggestion method. Scanning electron mi...

  14. Preparation of carbon and oxide co-modified LiFePO{sub 4} cathode material for high performance lithium-ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chun-Chen, E-mail: ccyang@mail.mcut.edu.tw [Department of Chemical Engineering, Ming Chi University of Technology, New Taipei City 243, Taiwan (China); Battery Research Center of Green Energy, Ming Chi University of Technology, New Taipei City 243, Taiwan (China); Jang, Jer-Huan; Jiang, Jia-Rong [Department of Chemical Engineering, Ming Chi University of Technology, New Taipei City 243, Taiwan (China); Department of Mechanical Engineering, Ming Chi University of Technology, New Taipei City 243, Taiwan (China)

    2015-09-01

    In this study, a LiFePO{sub 4}/C (LFP/C) material was prepared using a spray dry method. The Li{sub 4}Ti{sub 5}O{sub 12} (LTO) surface modification on LFP/C composite was performed by a sol–gel method. The characteristic properties were examined using X-ray diffraction, micro-Raman spectroscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy, an AC impedance method, and the galvanostatic charge/discharge method. Pristine LFP/C powder and the 1–5 wt.% LTO-coated LFP/C composites were compared. The results revealed that the 3 wt.% LTO-coated LFP/C composite showed the best performance among LFP composite samples. It was found that the 3 wt.% LTO-coated LFP/C composite showed discharge capacities of 159 mAh g{sup −1}, 157 mAh g{sup −1}, 154 mAh g{sup −1}, 148 mAh g{sup −1}, 145 mAh g{sup −1}, and 138 mAh g{sup −1} at rates of 0.2C, 0.5C, 1C, 3C, 5C, and 10C, respectively at 55 °C. The long-term cycling performance of the LFP/C composite was greatly improved when the dual hybrid coating (carbon and oxide) was carried out. Moreover, the 3 wt.% LTO-coated LFP/C composite with the lowest fading rate maintained cycling stability at 3C rate at 55 °C after 300 cycles; by contrast, the bare LFP/C sample with the highest fading rate had an unfavorable lifecycle, and its discharge capacity decreased rapidly. A hybrid coating is a feasible method for improving the high temperature performance of LFP/C composites. - Highlights: • A spherical LiFePO{sub 4}/C (LFP/C) material is first prepared by a spray dry process. • Li{sub 4}Ti{sub 5}O{sub 12} (LTO) modified LFP/C composite was carried out by a sol–gel method. • The LFP/C with a hybrid coating showed good cycling performance at elevated temperature. • 3%LTO-LFP/C composite showed excellent cycling stability at 55 °C for 300 cycles test.

  15. In Situ Analysis of the Li-O2 Battery with Thermally Reduced Graphene Oxide Cathode: Influence of Water Addition

    DEFF Research Database (Denmark)

    Storm, Mie Møller; Christensen, Mathias Kjærgård; Younesi, Reza

    2016-01-01

    The Li-O2 battery technology holds the promise to deliver a battery with significantly increased specific energy compared to today's Li-ion batteries. As a cathode support material, reduced graphene oxide has received increasing attention in the Li-O2 battery community due to the possibility...... of increased discharge capacity, increased battery cyclability, and decreased, charging, overpotential. In this. article we investigate the effect of water on a thermally, redircedigraphene, oxide cathode in a Li-O2 battery. Differential electrochemical mass spectrciscnieveals a, decreased electron count......-of-the cathode and not only on addition of water to the electrolyte as demonstrated by the solution-based mechanism In situ synchrotron X-ray diffraction experiment using a new design of a capillary-based Li-O2 cell with a thermally reduced graphene oxide cathode shows formation of LiOH along with Li2O2....

  16. Characteristics of an integrated cathode assembly for the electrolytic reduction of uranium oxide in a LiCl-Li2O molten salt

    International Nuclear Information System (INIS)

    Sung Bin Park; Byung Heung Park; Sang Mun Jeong; Jin Mok Hur; Chung Seok Seo; Seong Won Park; Seung-Hoon Choi

    2006-01-01

    Electrochemical behavior of the reduction of uranium oxide was studied in a LiCl-Li 2 O molten salt system with an integrated cathode assembly. The mechanism for the electrolytic reduction of uranium oxide was studied through cyclic voltammetry. By means of a chronopotentiometry, the effects of the thickness of the uranium oxide, the thickness of the MgO membrane and the material of the conductor of an integrated cathode assembly on the overpotential of the cathode were investigated. From the voltamograms, the reduction potential of the uranium oxide and Li 2 O was obtained and the two mechanisms of the electrolytic reduction were considered with regard to the applied cathode potential. From the chronopotentiograms, the exchange current, the transfer coefficient and the maximum allowable current based on the Tafel behavior were obtained with regard to the thickness of the uranium oxide, and of the MgO membrane and the material of the conductor of an integrated cathode assembly. (author)

  17. Durability and performance optimization of cathode materials for fuel cells

    Science.gov (United States)

    Colon-Mercado, Hector Rafael

    The primary objective of this dissertation is to develop an accelerated durability test (ADT) for the evaluation of cathode materials for fuel cells. The work has been divided in two main categories, namely high temperature fuel cells with emphasis on the Molten Carbonate Fuel Cell (MCFC) cathode current collector corrosion problems and low temperature fuel cells in particular Polymer Electrolyte Fuel Cell (PEMFC) cathode catalyst corrosion. The high operating temperature of MCFC has given it benefits over other fuel cells. These include higher efficiencies (>50%), faster electrode kinetics, etc. At 650°C, the theoretical open circuit voltage is established, providing low electrode overpotentials without requiring any noble metal catalysts and permitting high electrochemical efficiency. The waste heat is generated at sufficiently high temperatures to make it useful as a co-product. However, in order to commercialize the MCFC, a lifetime of 40,000 hours of operation must be achieved. The major limiting factor in the MCFC is the corrosion of cathode materials, which include cathode electrode and cathode current collector. In the first part of this dissertation the corrosion characteristics of bare, heat-treated and cobalt coated titanium alloys were studied using an ADT and compared with that of state of the art current collector material, SS 316. PEMFCs are the best choice for a wide range of portable, stationary and automotive applications because of their high power density and relatively low-temperature operation. However, a major impediment in the commercialization of the fuel cell technology is the cost involved due to the large amount of platinum electrocatalyst used in the cathode catalyst. In an effort to increase the power and decrease the cathode cost in polymer electrolyte fuel cell (PEMFC) systems, Pt-alloy catalysts were developed to increase its activity and stability. Extensive research has been conducted in the area of new alloy development and

  18. One-Pot Synthesis of Lithium-Rich Cathode Material with Hierarchical Morphology.

    Science.gov (United States)

    Luo, Kun; Roberts, Matthew R; Hao, Rong; Guerrini, Niccoló; Liberti, Emanuela; Allen, Christopher S; Kirkland, Angus I; Bruce, Peter G

    2016-12-14

    Lithium-rich transition metal oxides, Li 1+x TM 1-x O 2 (TM, transition metal), have attracted much attention as potential candidate cathode materials for next generation lithium ion batteries because their high theoretical capacity. Here we present the synthesis of Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 using a facile one-pot resorcinol-formaldehyde method. Structural characterization indicates that the material adopts a hierarchical porous morphology consisting of uniformly distributed small pores and disordered large pore structures. The material exhibits excellent electrochemical cycling stability and a good retention of capacity at high rates. The material has been shown to be both advantageous in terms of gravimetric and volumetric capacities over state of the art commercial cathode materials.

  19. Metalized, three-dimensional structured oxygen cathode materials for lithium/air batteries and method for making and using the same

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Weibing; Buettner-Garrett, Josh

    2017-04-18

    This disclosure relates generally to cathode materials for electrochemical energy cells, more particularly to metal/air electrochemical energy cell cathode materials containing silver vanadium oxide and methods of making and using the same. The metal/air electrochemical energy cell can be a lithium/air electrochemical energy cell. Moreover the silver vanadium oxide can be a catalyst for one or more of oxidation and reduction processes of the electrochemical energy cell.

  20. Cathodes for lithium ion batteries: the benefits of using nanostructured materials

    International Nuclear Information System (INIS)

    Bazito, Fernanda F.C.; Torresi, Roberto M.

    2006-01-01

    Commercially available lithium ion cells, which are the most advanced among rechargeable batteries available so far, employ microcrystalline transition metal oxides as cathodes, which function as Li insertion hosts. In search for better electrochemical performance the use of nanomaterials in place of these conventional ones has emerged as excellent alternative. In this review we present a brief introduction about the motivations to use nanostructured materials as cathodes in lithium ion batteries. To illustrate such advantages we present some examples of research directed toward preparations and electrochemical data of the most used cathodes in nanoscale, such as LiCoO 2 , LiMn 2 O 4 , LiMnO 2 , LiV 2 O 5 e LiFePO 4 . (author)

  1. Solid oxide fuel cell cathode with oxygen-reducing layer

    Science.gov (United States)

    Surdoval, Wayne A.; Berry, David A.; Shultz, Travis

    2018-04-03

    The disclosure provides a SOFC comprised of an electrolyte, anode, and cathode, where the cathode comprises an MIEC and an oxygen-reducing layer. The oxygen-reducing layer is in contact with the MIEC, and the MIEC is generally between and separating the oxygen-reducing layer and the electrolyte. The oxygen-reducing layer is comprised of single element oxides, single element carbonates, or mixtures thereof, and has a thickness of less than about 30 nm. In a particular embodiment, the thickness is less than 5 nm. In another embodiment, the thickness is about 3 monolayers or less. The oxygen-reducing layer may be a continuous film or a discontinuous film with various coverage ratios. The oxygen-reducing layer at the thicknesses described may be generated on the MIEC surface using means known in the art such as, for example, ALD processes.

  2. Activated graphene as a cathode material for Li-ion hybrid supercapacitors.

    Science.gov (United States)

    Stoller, Meryl D; Murali, Shanthi; Quarles, Neil; Zhu, Yanwu; Potts, Jeffrey R; Zhu, Xianjun; Ha, Hyung-Wook; Ruoff, Rodney S

    2012-03-14

    Chemically activated graphene ('activated microwave expanded graphite oxide', a-MEGO) was used as a cathode material for Li-ion hybrid supercapacitors. The performance of a-MEGO was first verified with Li-ion electrolyte in a symmetrical supercapacitor cell. Hybrid supercapacitors were then constructed with a-MEGO as the cathode and with either graphite or Li(4)Ti(5)O(12) (LTO) for the anode materials. The results show that the activated graphene material works well in a symmetrical cell with the Li-ion electrolyte with specific capacitances as high as 182 F g(-1). In a full a-MEGO/graphite hybrid cell, specific capacitances as high as 266 F g(-1) for the active materials at operating potentials of 4 V yielded gravimetric energy densities for a packaged cell of 53.2 W h kg(-1).

  3. Attempts to cathodically reduce boron oxides to borohydride in aqueous solution

    International Nuclear Information System (INIS)

    McLafferty, J.; Colominas, S.; Macdonald, D.D.

    2010-01-01

    Sodium borohydride is being considered as a chemical hydrogen storage material (hydrogen being released through hydrolysis) and as an anodic fuel for fuel cells. However, the current cost of sodium borohydride is prohibitively high for automotive applications. Thus, there is interest in recycling the by-product of the hydrolysis or oxidation reaction, sodium metaborate. Numerous patents claim that this reaction is feasible in aqueous solution. Here, we report extensive experiments based upon methods outlined in the patents (particularly, the so-called direct reduction using high overpotential cathode materials). We also attempt to address concerns not discussed in the patents. In particular, to the authors' knowledge, previous reports have not addressed electrostatic repulsion of metaborate anion from the cathode. We further report several methods that were designed to overcome this problem: (1) use of a cathode material having a very negative potential of zero charge, (2) modification of the electrical double layer by using specifically adsorbing tetraalkylammonium hydroxides, (3) use of a rectangular wave pulse, and (4) use of chemically modified cathodes. None of these methods produced measurable quantities of borohydride. We then speculate as to why this reaction is not feasible, at least in aqueous solutions.

  4. Improving the Performance of Layered Oxide Cathode Materials with Football-Like Hierarchical Structure for Na-Ion Batteries by Incorporating Mg2+ into Vacancies in Na-Ion Layers.

    Science.gov (United States)

    Li, Zheng-Yao; Wang, Huibo; Chen, Dongfeng; Sun, Kai; Yang, Wenyun; Yang, Jinbo; Liu, Xiangfeng; Han, Songbai

    2018-04-09

    The development of advanced cathode materials is still a great interest for sodium-ion batteries. The feasible commercialization of sodium-ion batteries relies on the design and exploitation of suitable electrode materials. This study offers a new insight into material design to exploit high-performance P2-type cathode materials for sodium-ion batteries. The incorporation of Mg 2+ into intrinsic Na + vacancies in Na-ion layers can lead to a high-performance P2-type cathode material for sodium-ion batteries. The materials prepared by the coprecipitation approach show a well-defined morphology of secondary football-like hierarchical structures. Neutron power diffraction and refinement results demonstrate that the incorporation of Mg 2+ into intrinsic vacancies can enlarge the space for Na-ion diffusion, which can increase the d-spacing of the (0 0 2) peak and the size of slabs but reduce the chemical bond length to result in an enhanced rate capability and cycling stability. The incorporation of Mg 2+ into available vacancies and a unique morphology make Na 0.7 Mg 0.05 Mn 0.8 Ni 0.1 Co 0.1 O 2 a promising cathode, which can be charged and discharged at an ultra-high current density of 2000 mA g -1 with an excellent specific capacity of 60 mAh g -1 . This work provides a new insight into the design of electrode materials for sodium-ion batteries. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Preliminary results on the chemical characterisation of the cathode nickel--emissive layer interface in oxide cathodes

    International Nuclear Information System (INIS)

    Jenkins, S.N.; Barber, D.K.; Whiting, M.J.; Baker, M.A.

    2003-01-01

    In cathode ray tube (CRT) thermionic oxide cathodes, the nickel-oxide interface properties are key to understanding the mechanisms of operation. At the elevated operational temperatures, free barium is formed at the interface by the reaction of reducing activators, from the nickel alloy, with barium oxide. The free barium diffuses to the outer surface of the oxide providing a low work function electron-emitting surface. However, during cathode life an interface layer grows between the nickel alloy and oxide, comprised of reaction products. The interfacial layer sets limits on the cathode performance and useful operational lifetime by inhibiting the barium reducing reaction. This paper discusses sample preparation procedures for exposure of the interface and the use of several surface and bulk analytical techniques to study interface layer formation. SEM, AES and SIMS data are presented, which provide preliminary insight into the mechanisms operating during the cathode's lifetime. There is evidence that the activator elements in the nickel alloy base, Al and Mg, are able to diffuse to the surface of the oxide during activation and ageing and that these elements are enriched at the interface after accelerated life

  6. Characterization of surface-modified LiMn2O4 cathode materials with indium tin oxide (ITO) coatings and their electrochemical performance

    International Nuclear Information System (INIS)

    Kim, Chang-Sam; Kwon, Soon-Ho; Yoon, Jong-Won

    2014-01-01

    Graphical abstract: -- Highlights: • Indium tin oxide (ITO) is used to modify the surface of LiMn 2 O 4 by a sol–gel method. • The surface-modified layer was observed at a scale of several nanometers on LiMn 2 O 4 . • The ITO-coated LiMn 2 O 4 shows better capacity retention at 30 and 55 °C than pristine LiMn 2 O 4 . -- Abstract: Indium tin oxide (ITO) is used to modify the surface of LiMn 2 O 4 by a sol–gel method in an attempt to improve its electrochemical performance at elevated temperatures. The surface-modified LiMn 2 O 4 is characterized via XRD, FE-SEM, TEM, Auger electron spectroscopy (AES) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The surface layer modified by substitution with indium was observed at a scale of several nanometers near the surface on LiMn 2 O 4 . The concentration of ITO for electrochemical performance was varied from 0.3 wt% to 0.8 wt%. The 0.5 wt% ITO coated LiMn 2 O 4 showed the best electrochemical performance. This enhancement in electrochemical performance is mainly attributed to the effect of the surface layer modified through ITO, which could suppress Mn dissolution and reduce the charge transfer resistance at the solid electrolyte interface

  7. Metal Nanoparticles and Carbon-Based Nanostructures as Advanced Materials for Cathode Application in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Pietro Calandra

    2010-01-01

    Full Text Available We review the most advanced methods for the fabrication of cathodes for dye-sensitized solar cells employing nanostructured materials. The attention is focused on metal nanoparticles and nanostructured carbon, among which nanotubes and graphene, whose good catalytic properties make them ideal for the development of counter electrode substrates, transparent conducting oxide, and advanced catalyst materials.

  8. The Impact of Strong Cathodic Polarization on SOC Electrolyte Materials

    DEFF Research Database (Denmark)

    Kreka, Kosova; Hansen, Karin Vels; Jacobsen, Torben

    2016-01-01

    One of the most promising reversible energy conversion/storage technologies is that of Solid Oxide Fuel/Electrolysis Cells (SOFC/SOEC, collectively termed SOC). Long term durability is typically required for such devises to become economically feasible, hence considerable amount of work has...... of impurities at the grain boundaries, electrode poisoning, delamination or cracks of the electrolyte etc., have been observed in cells operated at such conditions, lowering the lifetime of the cell1,2. High polarizations are observed at the electrolyte/cathode interface of an electrolysis cell operated at high...... current density. In case of a cell voltage above 1.6 V, p-type and n-type electronic conductivity are often observed at the anode and cathode respectively3. Hence, a considerable part of the current is lost as leakage through the electrolyte, thus lowering the efficiency of the cell considerably....

  9. Synthesis of tin oxide nanoparticle film by cathodic electrodeposition.

    Science.gov (United States)

    Kim, Seok; Lee, Hochun; Park, Chang Min; Jung, Yongju

    2012-02-01

    Three-dimensional SnO2 nanoparticle films were deposited onto a copper substrate by cathodic electrodeposition in a nitric acid solution. A new formation mechanism for SnO2 films is proposed based on the oxidation of Sn2+ ion to Sn4+ ion by NO+ ion and the hydrolysis of Sn4+. The particle size of SnO2 was controlled by deposition potential. The SnO2 showed excellent charge capacity (729 mAh/g) at a 0.2 C rate and high rate capability (460 mAh/g) at a 5 C rate.

  10. Development of multi-pixel x-ray source using oxide-coated cathodes.

    Science.gov (United States)

    Kandlakunta, Praneeth; Pham, Richard; Khan, Rao; Zhang, Tiezhi

    2017-07-07

    Multiple pixel x-ray sources facilitate new designs of imaging modalities that may result in faster imaging speed, improved image quality, and more compact geometry. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide-coated cathodes. Oxide cathodes have high emission efficiency and, thereby, produce high emission current density at low temperature when compared to traditional tungsten filaments. Indirectly heated micro-rectangular oxide cathodes were developed using carbonates, which were converted to semiconductor oxides of barium, strontium, and calcium after activation. Each cathode produces a focal spot on an elongated fixed anode. The x-ray beam ON and OFF control is performed by source-switching electronics, which supplies bias voltage to the cathode emitters. In this paper, we report the initial performance of the oxide-coated cathodes and the MPTEX source.

  11. Recent advances on Fe- and Mn-based cathode materials for lithium and sodium ion batteries

    Science.gov (United States)

    Zhu, Xiaobo; Lin, Tongen; Manning, Eric; Zhang, Yuancheng; Yu, Mengmeng; Zuo, Bin; Wang, Lianzhou

    2018-06-01

    The ever-growing market of electrochemical energy storage impels the advances on cost-effective and environmentally friendly battery chemistries. Lithium-ion batteries (LIBs) are currently the most critical energy storage devices for a variety of applications, while sodium-ion batteries (SIBs) are expected to complement LIBs in large-scale applications. In respect to their constituent components, the cathode part is the most significant sector regarding weight fraction and cost. Therefore, the development of cathode materials based on Earth's abundant elements (Fe and Mn) largely determines the prospects of the batteries. Herein, we offer a comprehensive review of the up-to-date advances on Fe- and Mn-based cathode materials for LIBs and SIBs, highlighting some promising candidates, such as Li- and Mn-rich layered oxides, LiNi0.5Mn1.5O4, LiFe1-xMnxPO4, NaxFeyMn1-yO2, Na4MnFe2(PO4)(P2O7), and Prussian blue analogs. Also, challenges and prospects are discussed to direct the possible development of cost-effective and high-performance cathode materials for future rechargeable batteries.

  12. Ab initio energetics of LaBO3(001) (B=Mn, Fe, Co, and Ni) for solid oxide fuel cell cathodes

    DEFF Research Database (Denmark)

    Lee, Yueh-Lin; Kleis, Jesper; Rossmeisl, Jan

    2009-01-01

    LaBO3 (B=Mn, Fe, Co, and Ni) perovskites form a family of materials of significant interest for cathodes of solid oxide fuel cells (SOFCs). In this paper ab initio methods are used to study both bulk and surface properties of relevance for SOFCs, including vacancy formation and oxygen binding...... reduction reaction on perovskite SOFC cathodes....

  13. Copper-substituted perovskite compositions for solid oxide fuel cell cathodes and oxygen reduction electrodes in other electrochemical devices

    Science.gov (United States)

    Rieke, Peter C [Pasco, WA; Coffey, Gregory W [Richland, WA; Pederson, Larry R [Kennewick, WA; Marina, Olga A [Richland, WA; Hardy, John S [Richland, WA; Singh, Prabhaker [Richland, WA; Thomsen, Edwin C [Richland, WA

    2010-07-20

    The present invention provides novel compositions that find advantageous use in making electrodes for electrochemical cells. Also provided are electrochemical devices that include active oxygen reduction electrodes, such as solid oxide fuel cells, sensors, pumps and the like. The compositions comprises a copper-substituted ferrite perovskite material. The invention also provides novel methods for making and using the electrode compositions and solid oxide fuel cells and solid oxide fuel cell assemblies having cathodes comprising the compositions.

  14. Carbonization kinetics of La2O3-Mo cathode materials

    International Nuclear Information System (INIS)

    Jinshu, W.; Meiling, Z.; Tieyong, Z.; Jiuxing, Z.; Zuoren, N.

    2001-01-01

    The carbonization kinetics of La 2 O 3 -Mo cathode materials has been studied by thermal analysis method. Three-stage model of the carbonization has been presented in this paper. The carbonization rate is initially controlled by chemical reaction, then controlled by chemical reaction mixed with diffusion, finally controlled by diffusion. After the initial experimental data are processed according to this model, the correlation coefficients of the kinetic curves are satisfactory. The apparent activation energy of carbonization of La 2 O 3 -Mo cathode materials has been obtained. At the same time, we have deduced the empirical expressions of the amount of weight increased per unit area after carbonization, temperature and time in the temperature range 1393 K - 1493 K. (author)

  15. Ni And Co Segregations On Selective Surface Facets And Rational Design Of Layered Lithium Transition-metal Oxide Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Pengfei; Zheng, Jianming; Zheng, Jiaxin; Wang, Zhiguo; Teng, Gaofeng; Kuppan, Saravanan; Xiao, Jie; Chen, Guoying; Zhang, Jiguang; Wang, Chong M.; Pan, Feng

    2016-05-05

    The chemical processes occurring on the surface of cathode materials during battery cycling play a crucial role in determining battery’s performance. However, our understanding on such surface chemistry is far from clear due to the complexity of redox chemistry during battery charge/discharge. In this work, through intensive aberration corrected STEM investigation on eight layered oxide cathode materials, we report two important findings on the pristine oxides. First, Ni and Co show strong plane selectivity when building up their respective surface segregation layers (SSL). Specifically, Ni-SSL is exclusively developed on (200)m facet in Li-Mn-rich oxides (monoclinic C2/m symmetry) and (012)h facet in Mn-Ni equally rich oxides (hexagonal R-3m symmetry), while Co-SSL has a strong preference to (20-2)m plane with minimal Co-SSL also developed on some other planes in LMR cathodes. Structurally, Ni-SSLs tend to form spinel-like lattice while Co-SSLs are in a rock-salt-like structure. Secondly, by increasing Ni concentration in these layered oxides, Ni and Co SSLs can be suppressed and even eliminated. Our findings indicate that Ni and Co SSLs are tunable through controlling particle morphology and oxide composition, which opens up a new way for future rational design and synthesis of cathode materials.

  16. Cathode Lens Mode of the SEM in Materials Science Applications

    Czech Academy of Sciences Publication Activity Database

    Frank, Luděk; Müllerová, Ilona; Matsuda, K.; Ikeno, S.

    2007-01-01

    Roč. 48, č. 5 (2007), s. 944-948 ISSN 1345-9678 R&D Projects: GA ČR GA102/05/2327; GA ČR GA202/04/0281 Institutional research plan: CEZ:AV0Z20650511 Keywords : electron microscopy of materials * scanning electron microscopy * low energy electron microscopy * cathode lens Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.018, year: 2007

  17. Defect thiospinels: a new class of reversible cathode material

    Science.gov (United States)

    James, A. C. W. P.; Goodenough, J. B.

    1989-05-01

    The defect thiospinel Cu 0.07[Ti 2]S 4 was prepared by low-temperature oxidative extraction of copper from Cu[Ti 2]S 4. Up to two equivalents of lithium can be inserted into Cu 0.07[Ti 2]S 4 reversibly with fast electrochemical kinetics at room temperature; the defect thiospinel is, therefore, a highly promising alternative to layered TiS 2 as a cathode material for lithium secondary batteries. Samples of Cu 1- x [Ti 2]S 4 (0⩽ x ⩽ 0.93) and Li xCu 0.07[Ti 2]S 4 (0 < x < 2) were prepared and characterised by 65Cu and 7Li solid-state NMR, neutron powder diffraction, and electrochemical measurements. Cu 0.07[Ti 2]S 4 is a semimetal with the residual copper located on the normal spinel A-cation sites. The lithium in Li xCu 0.07[Ti 2]S 4 is located only in the 16c octahedral sites of the spinel framework at all lithium compositions. The open-circuit voltage of Li xCu 0.07[Ti 2]S 4versus lithium metal is nearly identical to that of layered Li xTiS 2 over the whole lithium-composition range. The chemical diffusion constant of lithium in Li xCu 0.07[Ti 2]S 4 (0.5 ⩽ x⩽ 1.5) was found to be 1 × 10 -9 cm 2 s -1, which is comparable with that in layered Li xTiS 2.

  18. Highly Stable Aqueous Zinc-ion Storage Using Layered Calcium Vanadium Oxide Bronze Cathode

    KAUST Repository

    Xia, Chuan

    2018-02-12

    Cost-effective aqueous rechargeable batteries are attractive alternatives to non-aqueous cells for stationary grid energy storage. Among different aqueous cells, zinc-ion batteries (ZIBs), based on Zn2+ intercalation chemistry, stand out as they can employ high-capacity Zn metal as anode material. Herein, we report a layered calcium vanadium oxide bronze as cathode material for aqueous Zn batteries. For the storage of Zn2+ ions in aqueous electrolyte, we demonstrate that calcium based bronze structure can deliver a high capacity of 340 mAh g-1 at 0.2 C, good rate capability and very long cycling life (96% retention after 3000 cycles at 80 C). Further, we investigate the Zn2+ storage mechanism, and the corresponding electrochemical kinetics in this bronze cathode. Finally, we show that our Zn cell delivers an energy density of 267 Wh kg-1 at a power density of 53.4 W kg-1.

  19. Highly Stable Aqueous Zinc-ion Storage Using Layered Calcium Vanadium Oxide Bronze Cathode

    KAUST Repository

    Xia, Chuan; Guo, Jing; Li, Peng; Zhang, Xixiang; Alshareef, Husam N.

    2018-01-01

    Cost-effective aqueous rechargeable batteries are attractive alternatives to non-aqueous cells for stationary grid energy storage. Among different aqueous cells, zinc-ion batteries (ZIBs), based on Zn2+ intercalation chemistry, stand out as they can employ high-capacity Zn metal as anode material. Herein, we report a layered calcium vanadium oxide bronze as cathode material for aqueous Zn batteries. For the storage of Zn2+ ions in aqueous electrolyte, we demonstrate that calcium based bronze structure can deliver a high capacity of 340 mAh g-1 at 0.2 C, good rate capability and very long cycling life (96% retention after 3000 cycles at 80 C). Further, we investigate the Zn2+ storage mechanism, and the corresponding electrochemical kinetics in this bronze cathode. Finally, we show that our Zn cell delivers an energy density of 267 Wh kg-1 at a power density of 53.4 W kg-1.

  20. Evaluation of materials for bipolar plates in simulated PEM fuel-cell cathodic environments

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, S.V.; Belmonte, M.R.; Moron, L.E.; Torres, J.; Orozco, G. [Centro de Investigacion y Desarrollo Technologico en Electroquimica S.C. Parcque Sanfandila, Queretaro (Mexico); Perez-Quiroz, J.T. [Mexican Transport Inst., Queretaro (Mexico); Cortes, M. A. [Mexican Petroleum Inst., Mexico City (Mexico)

    2008-04-15

    The bipolar plates in proton exchange membrane fuel cells (PEMFC) are exposed to an oxidizing environment on the cathodic side, and therefore are susceptible to corrosion. Corrosion resistant materials are needed for the bipolar plates in order to improve the lifespan of fuel cells. This article described a study in which a molybdenum (Mo) coating was deposited over austenitic stainless steel 316 and carbon steel as substrates in order to evaluate the resulting surfaces with respect to their corrosion resistance in simulated anodic and cathodic PEMFC environments. The molybdenum oxide films were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The article presented the experiment and discussed the results of the corrosion behaviour of coated stainless steel. In general, the electrochemical characterization of bare materials and coated steel consisted of slow potentiodynamic polarization curves followed by a constant potential polarization test. The test medium was 0.5M sulfuric acid with additional introduction of oxygen to simulate the cathodic environment. All tests were performed at ambient temperature and at 50 degrees Celsius. The potentiostat used was a Gamry instrument. It was concluded that it is possible to deposit Mo-oxides on steel without using another alloying metal. The preferred substrate for corrosion prevention was found to be an alloy with high chromium content. 24 refs., 4 figs.

  1. Formation and effect of orientation domains in layered oxide cathodes of lithium-ion batteries

    International Nuclear Information System (INIS)

    Jarvis, Karalee A.; Wang, Chih-Chieh; Knight, James C.; Rabenberg, Lew; Manthiram, Arumugam; Ferreira, Paulo J.

    2016-01-01

    We show that in layered oxides that are employed as cathodes in lithium-ion batteries, the cation layers can order on different {111} NaCl planes within a single particle, which makes the lithium layer discontinuous across a particle. The findings challenge previous assertions that lithium undergoes 2-D diffusion in layered oxides and the data provide new insights into the decrease in rate capabilities for some layered oxides. Therefore, it is critically important to understand how these discontinuities form and how the loss of 2-D diffusion impacts the overall performance of the layered oxide cathode materials. Employing X-ray diffraction (XRD) and aberration-corrected scanning transmission electron microscopy (STEM), we find that as the material transitions from a disordered to an ordered state, it forms four orientation variants corresponding to the four {111} NaCl planes. This transition is not intrinsic to all layered oxides and appears to be more strongly affected by nickel. Furthermore, with energy dispersive spectroscopy (EDS), we show that there is an increase in the nickel concentration at the interface between each orientation variant. This reduces the rate of lithium diffusion, negatively affects the rate capability, and could be contributing to the overall capacity fade.

  2. Comparison of Nonprecious Metal Cathode Materials for Methane Production by Electromethanogenesis.

    KAUST Repository

    Siegert, Michael; Yates, Matthew D; Call, Douglas F; Zhu, Xiuping; Spormann, Alfred; Logan, Bruce E

    2014-01-01

    In methanogenic microbial electrolysis cells (MMCs), CO2 is reduced to methane using a methanogenic biofilm on the cathode by either direct electron transfer or evolved hydrogen. To optimize methane generation, we examined several cathode materials

  3. Reactivity between carbon cathode materials and electrolyte based on industrial and laboratory data

    CSIR Research Space (South Africa)

    Chauke, L

    2013-07-01

    Full Text Available Interaction between electrolyte and carbon cathodes during the electrolytic production of aluminium decreases cell life. This paper describes the interaction between carbon cathode materials and electrolyte, based on industrial and laboratory data...

  4. Mosaic-shaped cathode for highly durable solid oxide fuel cell under thermal stress

    Science.gov (United States)

    Joo, Jong Hoon; Jeong, Jaewon; Kim, Se Young; Yoo, Chung-Yul; Jung, Doh Won; Park, Hee Jung; Kwak, Chan; Yu, Ji Haeng

    2014-02-01

    In this study, we propose a novel "mosaic structure" for a SOFC (solid oxide fuel cell) cathode with high thermal expansion to improve the stability against thermal stress. Self-organizing mosaic-shaped cathode has been successfully achieved by controlling the amount of binder in the dip-coating solution. The anode-supported cell with mosaic-shaped cathode shows itself to be highly durable performance for rapid thermal cycles, however, the performance of the cell with a non-mosaic cathode exhibits severe deterioration originated from the delamination at the cathode/electrolyte interface after 7 thermal cycles. The thermal stability of an SOFC cathode can be evidently improved by controlling the surface morphology. In view of the importance of the thermal expansion properties of the cathode, the effects of cathode morphology on the thermal stress stability are discussed.

  5. Transition-metal chlorides as conversion cathode materials for Li-ion batteries

    International Nuclear Information System (INIS)

    Li Ting; Chen, Zhong X.; Cao, Yu L.; Ai, Xin P.; Yang, Han X.

    2012-01-01

    Insoluble AgCl and soluble CuCl 2 were selected and investigated as model compounds of transition-metal chlorides for electrochemical conversion cathode materials. The experimental results demonstrated that the AgCl nanocrystals can convert reversibly to metallic Ag with nearly full utilization of its one-electron redox capacity (187 mAh g −1 ). Similarly, the CuCl 2 -filled mesoporous carbon can realize a reversible two-electron transfer reaction, giving a very high reversible capacity of 466 mAh g −1 after 20 cycles. These data imply that the metal chlorides can undergo complete electrochemical conversion utilizing their full oxidation states for electrical energy storage as previously reported metal fluorides, possibly being used as high capacity cathode materials for Li-ion batteries.

  6. Graphene Modified LiFePO4 Cathode Materials for High Power Lithium ion Batteries

    International Nuclear Information System (INIS)

    Zhou, X.; Wang, F.; Zhu, Y.; Liu, Z.

    2011-01-01

    Graphene-modified LiFePO 4 composite has been developed as a Li-ion battery cathode material with excellent high-rate capability and cycling stability. The composite was prepared with LiFePO 4 nanoparticles and graphene oxide nanosheets by spray-drying and annealing processes. The LiFePO 4 primary nanoparticles embedded in micro-sized spherical secondary particles were wrapped homogeneously and loosely with a graphene 3D network. Such a special nanostructure facilitated electron migration throughout the secondary particles, while the presence of abundant voids between the LiFePO 4 nanoparticles and graphene sheets was beneficial for Li + diffusion. The composite cathode material could deliver a capacity of 70 mAh g -1 at 60C discharge rate and showed a capacity decay rate of <15% when cycled under 10C charging and 20C discharging for 1000 times.

  7. Dynamic behaviour of interphases and its implication on high-energy-density cathode materials in lithium-ion batteries

    Science.gov (United States)

    Li, Wangda; Dolocan, Andrei; Oh, Pilgun; Celio, Hugo; Park, Suhyeon; Cho, Jaephil; Manthiram, Arumugam

    2017-01-01

    Undesired electrode–electrolyte interactions prevent the use of many high-energy-density cathode materials in practical lithium-ion batteries. Efforts to address their limited service life have predominantly focused on the active electrode materials and electrolytes. Here an advanced three-dimensional chemical and imaging analysis on a model material, the nickel-rich layered lithium transition-metal oxide, reveals the dynamic behaviour of cathode interphases driven by conductive carbon additives (carbon black) in a common nonaqueous electrolyte. Region-of-interest sensitive secondary-ion mass spectrometry shows that a cathode-electrolyte interphase, initially formed on carbon black with no electrochemical bias applied, readily passivates the cathode particles through mutual exchange of surface species. By tuning the interphase thickness, we demonstrate its robustness in suppressing the deterioration of the electrode/electrolyte interface during high-voltage cell operation. Our results provide insights on the formation and evolution of cathode interphases, facilitating development of in situ surface protection on high-energy-density cathode materials in lithium-based batteries. PMID:28443608

  8. Cathodic cycling effects in the oxide films formed on zirconium alloys type AB2

    International Nuclear Information System (INIS)

    Zerbino, J.O; Visintin, A; Triaca, W

    2003-01-01

    The passive behavior of ZrNi alloys near the rest potential is studied through in situ voltammetry, ellipsometry, and microscopic observation.A significant oxide layer growth is observed in aqueous 1 M KOH during the application of different potential programs currently used in the activation processes of the alloy.The understanding of both the alloy activation process and the hydrogen absorption process is important in the strategies employed for the design of electrodes for nickel metal hydride batteries.The kinetics of the oxide layer formation, under potential cycling in the cathodic region related to the rest potential, plays a significant role in the activation process of metal alloy.Cathodic potential cycling increases the thickness and decreases the compactness of the passive oxide layer.The protonation of the oxide decreases the barrier effect and makes the anodic polarization more effective.Potential cycling gives rise to increasing surface oxidation, hydrogen absorption and hydride formation, and produces the consequent fragmentation of the material mainly through grain limits (J.Solid State Eletrochem. in press)

  9. Evidence of the Current Collector Effect: Study of the SOFC Cathode Material Ca3Co4O9+d

    NARCIS (Netherlands)

    Rolle, A.; Thoréton, V.; Rozier, P.; Capoen, E.; Mentré, O.; Boukamp, Bernard A.; Daviero-Minaud, S.

    2012-01-01

    In the study of the performance of solid oxide fuel cell (SOFC) electrodes, the possible influence of the applied current collector is often not mentioned or recognized. In this article, as part of an optimization study of the potentially attractive Ca3Co4O9+δ cathode material (Ca349), special

  10. On the nanostructuring and catalytic promotion of intermediate temperature solid oxide fuel cell (IT-SOFC) cathodes

    Science.gov (United States)

    Serra, José M.; Buchkremer, Hans-Peter

    Solid oxide fuel cells (SOFCs) are highly efficient energy converters for both stationary and mobile purposes. However, their market introduction still demands the reduction of manufacture costs and one possible way to reach this goal is the decrease of the operating temperatures, which entails the improvement of the cathode electrocatalytic properties. An ideal cathode material may have mixed ionic and electronic conductivity as well as proper catalytic properties. Nanostructuring and catalytic promotion of mixed conducting perovskites (e.g. La 0.58Sr 0.4Fe 0.8Co 0.2O 3- δ) seem to be promising approaches to overcoming cathode polarization problems and are briefly illustrated here. The preparation of nanostructured cathodes with relatively high surface area and enough thermal stability enables to improve the oxygen exchange rate and therefore the overall SOFC performance. A similar effect was obtained by catalytic promoting the perovskite surface, allowing decoupling the catalytic and ionic-transport properties in the cathode design. Noble metal incorporation may improve the reversibility of the reduction cycles involved in the oxygen reduction. Under the cathode oxidizing conditions, Pd seems to be partially dissolved in the perovskite structure and as a result very well dispersed.

  11. A high performance cathode for proton conducting solid oxide fuel cells

    KAUST Repository

    Wang, Zhiquan

    2015-01-01

    Intermediate temperature solid-oxide fuel cells (IT-SOFCs)), as one of the energy conversion devices, have attracted worldwide interest for their great fuel efficiency, low air pollution, much reduced cost and excellent longtime stability. In the intermediate temperature range (500-700°C), SOFCs based on proton conducting electrolytes (PSOFCs) display unique advantages over those based on oxygen ion conducting electrolytes. A key obstacle to the practical operation of past P-SOFCs is the poor stability of the traditionally used composite cathode materials in the steam-containing atmosphere and their low contribution to proton conduction. Here we report the identification of a new Ruddlesden-Popper-type oxide Sr3Fe2O7-δ that meets the requirements for much improved long-term stability and shows a superior single-cell performance. With a Sr3Fe2O7-δ-5 wt% BaZr0.3Ce0.5Y0.2O3-δ cathode, the P-SOFC exhibits high power densities (683 and 583 mW cm-2 at 700°C and 650°C, respectively) when operated with humidified hydrogen as the fuel and air as the cathode gas. More importantly, no decay in discharging was observed within a 100 hour test. © The Royal Society of Chemistry 2015.

  12. Lanthanum manganate based cathodes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Juhl Joergensen, M.

    2001-07-01

    Composite cathodes for solid oxide fuel cells were investigated using electrochemical impedance spectroscopy and scanning electron microscopy. The aim was to study the oxygen reduction process in the electrode in order to minimise the voltage drop in the cathode. The electrodes contained a composite layer made from lanthanum strontium manganate (LSM) and yttria stabilised zirconia (YSZ) and a layer of pure LSM aimed for current collection. The performance of the composite electrodes was sensitive to microstructure and thickness. Further, the interface between the composite and the current collecting layer proved to affect the performance. In a durability study severe deg-radation of the composite electrodes was found when passing current through the electrode for 2000 hours at 1000 deg. C. This was ascribed to pore formation along the composite interfaces and densification of the composite and current collector microstructure. An evaluation of the measurement approach indicated that impedance spectroscopy is a very sensitive method. This affects the reproducibility, as small undesirable variations in for instance the microstructure from electrode to electrode may change the impedance. At least five processes were found to affect the impedance of LSM/YSZ composite electrodes. Two high frequency processes were ascribed to transport of oxide ions/oxygen intermediates across LSM/YSZ interfaces and through YSZ in the composite. Several competitive elementary reaction steps, which appear as one medium frequency process in the impedance spectra, were observed. A low frequency arc related to gas diffusion limitation in a stagnant gas layer above the composite structure was detected. Finally, an inductive process, assumed to be connected to an activation process involving segregates at the triple phase boundary between electrode, electrolyte and gas phase, was found. (au)

  13. Manganese Sesquioxide as Cathode Material for Multivalent Zinc Ion Battery with High Capacity and Long Cycle Life

    International Nuclear Information System (INIS)

    Jiang, Baozheng; Xu, Chengjun; Wu, Changle; Dong, Liubing; Li, Jia; Kang, Feiyu

    2017-01-01

    Highlights: • Manganese oxides with Mn(III) state is firstly reported to store zinc ion. • Zinc ion battery with α-Mn 2 O 3 cathode is assembled. • Storage mechanism of zinc ion in α-Mn 2 O 3 is investigated. - Abstract: Rechargeable zinc ion battery is considered as one of the most potential energy storage devices for large-scale energy storage system due to its safety, low-cost, high capacity and nontoxicity. However, only a few cathode materials have been studied for rechargeable zinc ion batteries. Here, we firstly report manganese sesquioxide (Mn 2 O 3 ) with Mn(III) state as cathode material for rechargeable zinc ion battery. The α-Mn 2 O 3 cathode displays a reversible capacity of 148 mAh g −1 , which is relatively high among all the reported cathode materials for ZIB. The cathode also exhibits good rate capability and excellent cycling stability with a long cycle life up to 2000 times. The ion storage mechanism of α-Mn 2 O 3 in zinc ion battery was also revealed. The pristine α-Mn 2 O 3 undergoes a reversible phase transition from bixbyite structure to layered-type zinc birnessite during the electrochemical zinc ion insertion and extraction. The results not only benefit for the practical application of rechargeable zinc ion battery, but also broaden the horizons of understanding the electrochemical behavior and mechanism of rechargeable zinc ion batteries.

  14. Cathodic electrodeposition of ceramic and organoceramic materials. Fundamental aspects.

    Science.gov (United States)

    Zhitomirsky, I

    2002-03-29

    Electrodeposition of ceramic materials can be performed by electrophoretic (EPD) or electrolytic (ELD) deposition. Electrophoretic deposition is achieved via motion of charged particles towards an electrode under an applied electric field. Electrolytic deposition produces colloidal particles in cathodic reactions for subsequent deposition. Various electrochemical strategies and deposition mechanisms have been developed for electrodeposition of ceramic and organoceramic films, and are discussed in the present article. Electrode-position of ceramic and organoceramic materials includes mass transport, accumulation of particles near the electrode and their coagulation to form a cathodic deposit. Various types of interparticle forces that govern colloidal stability in the absence and presence of processing additives are discussed. Novel theoretical contributions towards an interpretation of particle coagulation near the electrode surface are reviewed. Background information is given on the methods of particle charging, stabilization of colloids in aqueous and non-aqueous media, electrophoretic mobility of ceramic particles and polyelectrolytes, and electrode reactions. This review also covers recent developments in the electrodeposition of ceramic and organoceramic materials.

  15. Surface-initiated growth of thin oxide coatings for Li-sulfur battery cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyu Tae; Black, Robert; Yim, Taeeun; Ji, Xiulei; Nazar, Linda F. [University of Waterloo, Department of Chemistry, Waterloo, ON (Canada)

    2012-12-15

    The concept of surface-initiated growth of oxides on functionalized carbons is introduced as a method to inhibit the dissolution of polysulfide ions in Li-S battery cathode materials. MO{sub x} (M: Si, V) thin layers are homogeneously coated on nanostructured carbon-sulfur composites. The coating significantly inhibits the dissolution of polysulfides on cycling, resulting in enhanced cycle performance and coulombic efficiency of the Li-S battery. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Titanium-Niobium Oxides as Non-Noble Metal Cathodes for Polymer Electrolyte Fuel Cells

    Directory of Open Access Journals (Sweden)

    Akimitsu Ishihara

    2015-07-01

    Full Text Available In order to develop noble-metal- and carbon-free cathodes, titanium-niobium oxides were prepared as active materials for oxide-based cathodes and the factors affecting the oxygen reduction reaction (ORR activity were evaluated. The high concentration sol-gel method was employed to prepare the precursor. Heat treatment in Ar containing 4% H2 at 700–900 °C was effective for conferring ORR activity to the oxide. Notably, the onset potential for the ORR of the catalyst prepared at 700 °C was approximately 1.0 V vs. RHE, resulting in high quality active sites for the ORR. X-ray (diffraction and photoelectron spectroscopic analyses and ionization potential measurements suggested that localized electronic energy levels were produced via heat treatment under reductive atmosphere. Adsorption of oxygen molecules on the oxide may be governed by the localized electronic energy levels produced by the valence changes induced by substitutional metal ions and/or oxygen vacancies.

  17. Copper sulfates as cathode materials for Li batteries

    Energy Technology Data Exchange (ETDEWEB)

    Schwieger, Jonathan N.; Kraytsberg, Alexander; Ein-Eli, Yair [Technion Israel Institute of Technology, Department of Materials Engineering, Technion City, Haifa 32000 (Israel)

    2011-02-01

    As lithium battery technology sets out to bridge the gap between portable electronics and the electrical automotive industry, cathode materials still stand as the bottleneck regarding performances. In the realm of highly attractive polyanion-type structures as high-voltage cathode materials, the sulfate group (SO{sub 4}){sup 2-} possesses an acknowledged superiority over other contenders in terms of open circuit voltage arising from the inductive effect of strong covalent S-O bonds. In parallel, novel lithium insertion mechanisms are providing alternatives to traditional intercalation, enabling reversible multi-electron processes securing high capacities. Combining both of these advantageous features, we report here the successful electrochemical reactivity of copper sulfate pentahydrate (CuSO{sub 4}.5H{sub 2}O) with respect to lithium insertion via a two-electron displacement reaction entailing the extrusion of metallic copper at a dual voltage of 3.2 V and 2.7 V followed by its reversible insertion at 3.5 V and 3.8 V. At this stage, cyclability was still shown to be limited due to the irreversible degradation to a monohydrate structure owing to constitutional water loss. (author)

  18. Copper sulfates as cathode materials for Li batteries

    Science.gov (United States)

    Schwieger, Jonathan N.; Kraytsberg, Alexander; Ein-Eli, Yair

    As lithium battery technology sets out to bridge the gap between portable electronics and the electrical automotive industry, cathode materials still stand as the bottleneck regarding performances. In the realm of highly attractive polyanion-type structures as high-voltage cathode materials, the sulfate group (SO 4) 2- possesses an acknowledged superiority over other contenders in terms of open circuit voltage arising from the inductive effect of strong covalent S-O bonds. In parallel, novel lithium insertion mechanisms are providing alternatives to traditional intercalation, enabling reversible multi-electron processes securing high capacities. Combining both of these advantageous features, we report here the successful electrochemical reactivity of copper sulfate pentahydrate (CuSO 4·5H 2O) with respect to lithium insertion via a two-electron displacement reaction entailing the extrusion of metallic copper at a dual voltage of 3.2 V and 2.7 V followed by its reversible insertion at 3.5 V and 3.8 V. At this stage, cyclability was still shown to be limited due to the irreversible degradation to a monohydrate structure owing to constitutional water loss.

  19. Effect of Internal Pressure and Temperature on Phase Transitions in Perovskite Oxides: The Case of the Solid Oxide Fuel Cell Cathode Materials of the La2-xSrxCoTiO6 Series.

    Science.gov (United States)

    Gómez-Pérez, Alejandro; Hoelzel, Markus; Muñoz-Noval, Álvaro; García-Alvarado, Flaviano; Amador, Ulises

    2016-12-19

    The symmetry of the room-temperature (RT) structure of title compounds La 2-x Sr x CoTiO 6-δ changes with x, from P2 1 /n (0 ≤ x ≤ 0.2) to Pnma (0.3 ≤ x ≤ 0.5) and to R3̅c (0.6 ≤ x ≤ 1). For x = 1 the three pseudocubic cell parameters become very close suggesting a transition to a cubic structure for higher Sr contents. Similar phase transitions were expected to occur on heating, paralleling the effect of internal pressure induced by substitution of La 3+ by Sr 2+ . However, only some of these aforementioned transitions have been thermally induced. The symmetry-adapted modes formalism is used in the structural refinements and fitting of neutron diffraction data recorded from RT to 1273 K. Thus, for x = 1, the out-of-phase tilting of the BO 6 octahedra vanishes progressively on heating, and a cubic structure with Pm3̅m symmetry is found at 1073 K. For lower Sr contents this transition is predicted to occur far above the temperature limit of common experimental setups. The analysis of the evolution of the perovskite tolerance factor, t-factor, with both Sr content and temperature indicates that temperature has a limited ability to release structural stress and thus to enable transitions to more symmetric phases. This is particularly true when compared to the effect of internal pressure induced by substitution of La by Sr. The existence of phase transitions in materials for solid oxide fuel cells that are usually exposed to heating-cooling cycles may have a detrimental effect. This work suggests strategies to stabilize the high-symmetry high-temperature phase of perovskite oxides through internal-pressure chemically induced.

  20. Optimizing solid oxide fuel cell cathode processing route for intermediate temperature operation

    DEFF Research Database (Denmark)

    Ortiz-Vitoriano, N.; Bernuy-Lopez, Carlos; Ruiz de Larramendi, I.

    2013-01-01

    -priced raw material and cost-effective production techniques.In this work the perovskite-type La0.6Ca0.4Fe0.8Ni0.2O3 (LCFN) oxide has been used in order to optimize intermediate temperature SOFC cathode processing route. The advantages this material presents arise from the low temperature powder calcination......For Solid Oxide Fuel Cells (SOFCs) to become an economically attractive energy conversion technology suitable materials which allow operation at lower temperatures, while retaining cell performance, must be developed. At the same time, the cell components must be inexpensive - requiring both low...... (∼600°C) and electrode sintering (∼800°C) of LCFN electrodes, making them a cheaper alternative to conventional SOFC cathodes. An electrode polarization resistance as low as 0.10Ωcm2 at 800°C is reported, as determined by impedance spectroscopy studies of symmetrical cells sintered at a range...

  1. Reduced graphene oxide encapsulated sulfur spheres for the lithium-sulfur battery cathode

    Directory of Open Access Journals (Sweden)

    Feiyan Liu

    Full Text Available Reduced graphene oxide (rGO encapsulated sulfur spheres for the Li-S batteries were prepared via the redox reaction between sodium polysulfide. XRD spectra showed that the diffraction peak of graphite oxide (GO at 10° disappeared, while the relatively weak diffraction peak at 27° belongs to graphene emerged. FT-IR spectra showed that the vibrations of the functional groups of GO, such as 3603 cm−1, 1723 cm−1and 1619 cm−1 which contributed from OH, COC and CO respectively, disappeared when compared to the spectra of GSC. SEM observations indicated that the optimum experimental condition followed as: mass ratio of GO and S was 1:1, 10% NaOH was used to adjust the pH. EDX analysis showed that the sulfur content reached at 68.8% of the composite material. The resultant electric resistance was nearly less than GO’s resistance in three orders of magnitude under same condition. Further electrochemical performance tests showed a coulombic efficiency was 96% from the first cycle capacity was 827 mAh g−1, to 388 mAh g−1 in the 100 cycles. This study carries substantial significance to the development of Li-S battery cathode materials. Keywords: Lithium-sulfur battery, Graphene, Sulfur spheres, Cathode material

  2. Investigation of structural and electrochemical properties of LaSrCo{sub 1−x}Sb{sub x}O{sub 4} (0≤x≤0.20) as potential cathode materials in intermediate-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Junkai; Zhou, Jun, E-mail: zhoujun@mail.xjtu.edu.cn; Fan, Weiwei; Wang, Wendong; Wu, Kai; Cheng, Yonghong

    2017-03-15

    The structural and electrochemical properties of the layered perovskite oxides LaSrCo{sub 1−x}Sb{sub x}O{sub 4} (0≤x≤0.20) were investigated to study the effects of substituting Sb for Co for application as cathode materials in intermediate temperature solid oxide fuel cells (IT-SOFCs). The results of crystal structure analyses show the maximum content of Sb in LaSrCo{sub 1−x}Sb{sub x}O{sub 4} to be 0.05 as a pure single phase. XPS shows that Co and Sb in LaSrCo{sub 0.95}Sb{sub 0.05}O{sub 4} may possess mixed-oxidation states. The electrical conductivity increased greatly after Sb substitution. An improvement in the cathode polarization (R{sub p}) values is observed from the Sb-doped sample with respect to the undoped samples. For example, R{sub p} of LaSrCo{sub 0.95}Sb{sub 0.05}O{sub 4} on LSGM was observed to be 0.16 Ω cm{sup 2} at 800 °C in air. The main rate-limiting step for LaSrCo{sub 0.95}Sb{sub 0.05}O{sub 4} cathode is charge transfer of oxygen atoms. These results indicate that Sb can be incorporated into LaSrCo{sub 1−x}Sb{sub x}O{sub 4} based materials and can have a beneficial effect on the performance, making them potentially suitable for use as cathode materials in IT-SOFCs. - Graphical abstract: The oxygen partial pressure dependence of polarization resistances for a new layered perovskite cathode LaSrCo{sub 0.95}Sb{sub 0.05}O{sub 4} at various temperatures was measured. - Highlights: • The maximum content of Sb was 0.05 mol in LaSrCo{sub 1−x}Sb{sub x}O{sub 4}. • The maximum electrical conductivity is 194 S cm{sup −1}for LaSrCo{sub 0.95}Sb{sub 0.05}O{sub 4} at 800 °C. • A rate-limiting process of charge transfer presented.

  3. Nanostructured LnBaCo2O6− (Ln = Sm, Gd with layered structure for intermediate temperature solid oxide fuel cell cathodes

    Directory of Open Access Journals (Sweden)

    Augusto E. Mejía Gómez

    2017-04-01

    Full Text Available In this work, we present the combination of two characteristics that are beneficial for solid oxide fuel cell (SOFC cathodic performance in one material. We developed and evaluated for the first time nanostructured layered perovskites of formulae LnBaCo2O6-d with Ln = Sm and Gd (SBCO and GBCO, respectively as SOFC cathodes, finding promising electrochemical properties in the intermediate temperature range. We obtained those nanostructures by using porous templates to confine the chemical reagents in regions of 200-800 nm. The performance of nanostructured SBCO and GBCO cathodes was analyzed by electrochemical impedance spectroscopy technique under different operating conditions using Gd2O3-doped CeO2 as electrolyte. We found that SBCO cathodes displayed lower area-specific resistance than GBCO ones, because bulk diffusion of oxide ions is enhanced in the former. We also found that cathodes synthesized using smaller template pores exhibited better performance.

  4. Cobalt-free perovskite Pr{sub 0.5}Sr{sub 0.5}Fe{sub 1−x}Cu{sub x}O{sub 3−δ} (PSFC) as a cathode material for intermediate temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Caroline G., E-mail: caroline.materiais@gmail.com [Materials Science and Engineering Postgraduate Program, UFRN, 59078-970, Natal (Brazil); Grilo, João Paulo de F. [Materials Science and Engineering Postgraduate Program, UFRN, 59078-970, Natal (Brazil); Macedo, Daniel A., E-mail: damaced@gmail.com [Materials Science and Engineering Postgraduate Program, UFPB, 58051-900, João Pessoa (Brazil); Cesário, Moisés R.; Fagg, Duncan Paul [Department of Mechanical Engineering, University of Aveiro, 3810-193, Aveiro (Portugal); Nascimento, Rubens M. [Materials Science and Engineering Postgraduate Program, UFRN, 59078-970, Natal (Brazil)

    2016-09-01

    PSFC (Pr{sub 0.5}Sr{sub 0.5}Fe{sub 1−x}Cu{sub x}O{sub 3−δ}) is a new perovskite-type oxide that has gained considerable attention as cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs), due to its high mixed ionic-electronic conductivity below 800 °C. In this work, PSFC (Pr{sub 0.5}Sr{sub 0.5}Fe{sub 1−x}Cu{sub x}O{sub 3−δ}, x = 0.2 and 0.4) powders were synthesized by the citrate method and structurally characterized by X-ray diffractometry. Screen-printed cathodes were sintered at 1050 °C and electrochemically characterized by impedance spectroscopy at 600–800 °C in pure oxygen. The area specific resistances (ASR) of the Pr{sub 0.5}Sr{sub 0.5}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−δ} material are shown to be competitive with typical values reported for cobalt-based cathodes in the measured temperature range, while, importantly, offering a significantly lower activation energy, 0.62 eV. The thermal expansion coefficients of these Co-free cathodes are in the range of 13–15 × 10{sup −6} °C{sup −1}, in a temperature range 200–650 °C, demonstrating a good thermal compatibility with gadolinia doped ceria (CGO) electrolytes. - Highlights: • Cobalt-free Pr{sub 0.5}Sr{sub 0.5}Fe{sub 1−x}Cu{sub x}O{sub 3−δ} (PSFC) cathodes successfully prepared by the citrate method. • PSFC cathodes are thermally compatible with CGO electrolytes. • Pr{sub 0.5}Sr{sub 0.5}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−δ} presents competitive area specific resistances of low activation energy, 0.62 eV.

  5. In Situ X-ray Diffraction Studies of Cathode Materials in Lithium Batteries

    International Nuclear Information System (INIS)

    Yang, X. Q.; Sun, X.; McBreen, J.; Mukerjee, S.; Gao, Yuan; Yakovleva, M. V.; Xing, X. K.; Daroux, M. L.

    1998-01-01

    There is an increasing interest in lithiated transition metal oxides because of their use as cathodes in lithium batteries. LiCoO 2 , LiNiO 2 and LiMn 2 O 4 are the three most widely used and studied materials, At present, although it is relative expensive and toxic, LiCoO 2 is the material of choice in commercial lithium ion batteries because of its ease of manufacture, better thermal stability and cycle life. However, the potential use of lithium ion batteries with larger capacity for power tools and electric vehicles in the future will demand new cathode materials with higher energy density, lower cost and better thermal stability. LiNiO 2 is isostructural with LiCoO 2 . It offers lower cost and high energy density than LiCoO 2 . However, it has much poorer thermal stability than LiCoO 2 , in the charged (delithiated) state. Co, Al, and other elements have been used to partially replace Ni in LiNiO 2 system in order to increase the thermal stability. LiMn 2 O 4 has the highest thermal stability and lowest cost and toxicity. However, the low energy density and poor cycle life at elevated temperature are the major obstacles for this material. In order to develop safer, cheaper, and better performance cathode materials, the in-depth understanding of the relationships between the thermal stability and structure, performance and structure are very important. The performance here includes energy density and cycle life of the cathode materials. X-ray diffraction (XRD) is one of the most powerful tools to study these relationships. The pioneer ex situ XRD work on cathode materials for lithium batteries was done by Ohzuku. His XRD studies on LiMn 2 O 4 , LiCoO 2 , LiNiO 2 , LiNi 0.5 Co 0.5 O 2 , and LiAl x Ni 1-x O 2 cathodes at different states of charge have provided important guidelines for the development of these new materials. However, the kinetic nature of the battery system definitely requires an in situ XRD technique to study the detail structural changes of the

  6. Oxidation reaction of polyether-based material and its suppression in lithium rechargeable battery using 4 V class cathode, LiNi1/3Mn1/3Co1/3O2.

    Science.gov (United States)

    Kobayashi, Takeshi; Kobayashi, Yo; Tabuchi, Masato; Shono, Kumi; Ohno, Yasutaka; Mita, Yuichi; Miyashiro, Hajime

    2013-12-11

    The all solid-state lithium battery with polyether-based solid polymer electrolyte (SPE) is regarded as one of next-generation lithium batteries, and has potential for sufficient safety because of the flammable-electrolyte-free system. It has been believed that polyether-based SPE is oxidized at the polymer/electrode interface with 4 V class cathodes. Therefore, it has been used for electric devices such as organic transistor, and lithium battery under 3 V. We estimated decomposition reaction of polyether used as SPE of all solid-state lithium battery. We first identified the decomposed parts of polyether-based SPE and the conservation of most main chain framework, considering the results of SPE analysis after long cycle operations. The oxidation reaction was found to occur slightly at the ether bond in the main chain with the branched side chain. Moreover, we resolved the issue by introducing a self-sacrificing buffer layer at the interface. The introduction of sodium carboxymethyl cellulose (CMC) to the 4 V class cathode surface led to the suppression of SPE decomposition at the interface as a result of the preformation of a buffer layer from CMC, which was confirmed by the irreversible exothermic reaction during the first charge, using electrochemical calorimetry. The attained 1500 cycle operation is 1 order of magnitude longer than those of previously reported polymer systems, and compatible with those of reported commercial liquid systems. The above results indicate to proceed to an intensive research toward the realization of 4 V class "safe" lithium polymer batteries without flammable liquid electrolyte.

  7. Prediction of solid oxide fuel cell cathode activity with first-principles descriptors

    DEFF Research Database (Denmark)

    Lee, Yueh-Lin; Kleis, Jesper; Rossmeisl, Jan

    2011-01-01

    In this work we demonstrate that the experimentally measured area specific resistance and oxygen surface exchange of solid oxide fuel cell cathode perovskites are strongly correlated with the first-principles calculated oxygen p-band center and vacancy formation energy. These quantities...... are therefore descriptors of catalytic activity that can be used in the first-principles design of new SOFC cathodes....

  8. Initial chemical transport of reducing elements and chemical reactions in oxide cathode base metal

    International Nuclear Information System (INIS)

    Roquais, J.M.; Poret, F.; Doze, R. le; Dufour, P.; Steinbrunn, A.

    2002-01-01

    In the present work, the formation of compounds associated to the diffusion of reducing elements (Mg and Al) to the nickel surface of a one-piece oxide cathode has been studied. Those compounds have been evidenced after the annealing steps at high temperature performed on cathode base metal prior to the emitting coating deposition. Therefore, they form the ''initial'' interface between the nickel and the coating, in other words, the interface existing at the beginning of cathode life. Extensive analysis to characterize the nickel base prior to coating deposition has been performed by means of scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), Auger electron spectroscopy (AES), transmission electron microscopy (TEM), and glow discharge optical emission spectroscopy (GDOES). TEM and AES analysis have allowed to identify for the first time a spinel compound of MgAl 2 O 4 . The preferential distribution of the different compounds on the nickel surface has been studied by EDX mapping. Experimental profiles of diffusion of the reducing elements in the nickel have been obtained over the entire thickness of the material by GDOES. The mechanism of formation of these compounds together with a related diffusion model are proposed

  9. Mechanistic modelling of a cathode-supported tubular solid oxide fuel cell

    Science.gov (United States)

    Suwanwarangkul, R.; Croiset, E.; Pritzker, M. D.; Fowler, M. W.; Douglas, P. L.; Entchev, E.

    A two-dimensional mechanistic model of a tubular solid oxide fuel cell (SOFC) considering momentum, energy, mass and charge transport is developed. The model geometry of a single cell comprises an air-preheating tube, air channel, fuel channel, anode, cathode and electrolyte layers. The heat radiation between cell and air-preheating tube is also incorporated into the model. This allows the model to predict heat transfer between the cell and air-preheating tube accurately. The model is validated and shows good agreement with literature data. It is anticipated that this model can be used to help develop efficient fuel cell designs and set operating variables under practical conditions. The transport phenomena inside the cell, including gas flow behaviour, temperature, overpotential, current density and species concentration, are analysed and discussed in detail. Fuel and air velocities are found to vary along flow passages depending on the local temperature and species concentrations. This model demonstrates the importance of incorporating heat radiation into a tubular SOFC model. Furthermore, the model shows that the overall cell performance is limited by O 2 diffusion through the thick porous cathode and points to the development of new cathode materials and designs being important avenues to enhance cell performance.

  10. Nanotubes of rare earth cobalt oxides for cathodes of intermediate-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Sacanell, Joaquin [Departamento de Fisica, Centro Atomico Constituyentes, CNEA, Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); CINSO (Centro de Investigaciones en Solidos), CITEFA-CONICET, J.B. de La Salle 4397, 1603 Villa Martelli, Buenos Aires (Argentina); Leyva, A. Gabriela [Departamento de Fisica, Centro Atomico Constituyentes, CNEA, Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, UNSAM. Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Bellino, Martin G.; Lamas, Diego G. [CINSO (Centro de Investigaciones en Solidos), CITEFA-CONICET, J.B. de La Salle 4397, 1603 Villa Martelli, Buenos Aires (Argentina)

    2010-04-02

    In this work we studied the electrochemical properties of cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) prepared with nanotubes of La{sub 0.6}Sr{sub 0.4}CoO{sub 3} (LSCO). Their nanostructures consist of agglomerated nanoparticles in tubular structures of sub-micrometric diameter. The resulting cathodes are highly porous both at the micro- and the nanoscale. This fact increases significantly the access to active sites for the oxygen reduction. We investigated the influence of the diameter of the precursor nanotubes on the polarization resistance of the LSCO cathodes on CeO{sub 2}-10 mol.% Sm{sub 2}O{sub 3} (SDC) electrolytes under air atmosphere, evaluated in symmetrical [LSCO/SDC/LSCO] cells. Our results indicate an optimized performance when the diameter of precursor nanotubes is sufficiently small to become dense nanorods after cathode sintering. We present a phenomenological model that successfully explains the behavior observed and considers that a small starting diameter acts as a barrier that prevents grains growth. This is directly related with the lack of contact points between nanotubes in the precursor, which are the only path for the growth of ceramic grains. We also observed that a conventional sintering process (of 1 h at 1000 C with heating and cooling rates of 10 C min{sup -1}) has to be preferred against a fast firing one (1 or 2 min at 1100 C with heating and cooling rates of 100 C min{sup -1}) in order to reach a higher performance. However, a good adhesion of the cathode can be achieved with both methods. Our results suggest that oxygen vacancy diffusion is enhanced while decreasing LSCO particle size. This indicates that the high performance of our nanostructured cathodes is not only related with the increase of the number of active sites for oxygen reduction but also to the fact that the nanotubes are formed by nanoparticles. (author)

  11. The explosive cathode on the base of carbon-fibrous plastic material

    International Nuclear Information System (INIS)

    Korenev, S.A.; Baranov, A.M.; Kostyuchenko, S.V.; Chernenko, N.M.

    1988-01-01

    Production process of exploseve cathodes on the base of carbon-fibrous plastic material of any geometric form and size is discussed. Experimental study of current take-off from cathodes with diameter 2 cm of 10 kV and 150-250 kV voltage are given. It is shown that ignition voltage of cathode plasma is 2 kV with 5 mm gap electrode of diode and 5 ·10 -5 Tor pressure of residual gas. It is shown that carbon-fibrous cathode, made by this technology, provides more stable current take-off electron beam (withoud oscillations) in comparison with other cathodes

  12. Novel copper redox-based cathode materials for room-temperature sodium-ion batteries

    Science.gov (United States)

    Xu, Shu-Yin; Wu, Xiao-Yan; Li, Yun-Ming; Hu, Yong-Sheng; Chen, Li-Quan

    2014-11-01

    Layered oxides of P2-type Na0.68Cu0.34Mn0.66O2, P2-type Na0.68Cu0.34Mn0.50Ti0.16O2, and O'3-type NaCu0.67Sb0.33O2 were synthesized and evaluated as cathode materials for room-temperature sodium-ion batteries. The first two materials can deliver a capacity of around 70 mAh/g. The Cu2+ is oxidized to Cu3+ during charging, and the Cu3+ goes back to Cu2+ upon discharging. This is the first demonstration of the highly reversible change of the redox couple of Cu2+/Cu3+ with high storage potential in secondary batteries.

  13. Combined theoretical and experimental analysis of processes determining cathode performance in solid oxide fuel cells.

    Science.gov (United States)

    Kuklja, M M; Kotomin, E A; Merkle, R; Mastrikov, Yu A; Maier, J

    2013-04-21

    Solid oxide fuel cells (SOFC) are under intensive investigation since the 1980's as these devices open the way for ecologically clean direct conversion of the chemical energy into electricity, avoiding the efficiency limitation by Carnot's cycle for thermochemical conversion. However, the practical development of SOFC faces a number of unresolved fundamental problems, in particular concerning the kinetics of the electrode reactions, especially oxygen reduction reaction. We review recent experimental and theoretical achievements in the current understanding of the cathode performance by exploring and comparing mostly three materials: (La,Sr)MnO3 (LSM), (La,Sr)(Co,Fe)O3 (LSCF) and (Ba,Sr)(Co,Fe)O3 (BSCF). Special attention is paid to a critical evaluation of advantages and disadvantages of BSCF, which shows the best cathode kinetics known so far for oxides. We demonstrate that it is the combined experimental and theoretical analysis of all major elementary steps of the oxygen reduction reaction which allows us to predict the rate determining steps for a given material under specific operational conditions and thus control and improve SOFC performance.

  14. The effect of oxygen transfer mechanism on the cathode performance based on proton-conducting solid oxide fuel cells

    KAUST Repository

    Hou, Jie

    2015-01-01

    Two types of proton-blocking composites, La2NiO4+δ-LaNi0.6Fe0.4O3-δ (LNO-LNF) and Sm0.2Ce0.8O2-δ-LaNi0.6Fe0.4O3-δ (SDC-LNF), were evaluated as cathode materials for proton-conducting solid oxide fuel cells (H-SOFCs) based on the BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte, in order to compare and investigate the influence of two different oxygen transfer mechanism on the performance of the cathode for H-SOFCs. The X-ray diffraction (XRD) results showed that the chemical compatibility of the components in both compounds was excellent up to 1000°C. Electrochemical studies revealed that LNO-LNF showed lower area specific polarization resistances in symmetrical cells and better electrochemical performance in single cell tests. The single cell with LNO-LNF cathode generated remarkable higher maximum power densities (MPDs) and lower interfacial polarization resistances (Rp) than that with SDC-LNF cathode. Correspondingly, the MPDs of the single cell with the LNO-LNF cathode were 490, 364, 266, 180 mW cm-2 and the Rp were 0.103, 0.279, 0.587, 1.367 Ω cm2 at 700, 650, 600 and 550°C, respectively. Moreover, after the single cell with LNO-LNF cathode optimized with an anode functional layer (AFL) between the anode and electrolyte, the power outputs reached 708 mW cm-2 at 700°C. These results demonstrate that the LNO-LNF composite cathode with the interstitial oxygen transfer mechanism is a more preferable alternative for H-SOFCs than SDC-LNF composite cathode with the oxygen vacancy transfer mechanism.

  15. Computational Screening for Design of Optimal Coating Materials to Suppress Gas Evolution in Li-Ion Battery Cathodes.

    Science.gov (United States)

    Min, Kyoungmin; Seo, Seung-Woo; Choi, Byungjin; Park, Kwangjin; Cho, Eunseog

    2017-05-31

    Ni-rich layered oxides are attractive materials owing to their potentially high capacity for cathode applications. However, when used as cathodes in Li-ion batteries, they contain a large amount of Li residues, which degrade the electrochemical properties because they are the source of gas generation inside the battery. Here, we propose a computational approach to designing optimal coating materials that prevent gas evolution by removing residual Li from the surface of the battery cathode. To discover promising coating materials, the reactions of 16 metal phosphates (MPs) and 45 metal oxides (MOs) with the Li residues, LiOH, and Li 2 CO 3 are examined within a thermodynamic framework. A materials database is constructed according to density functional theory using a hybrid functional, and the reaction products are obtained according to the phases in thermodynamic equilibrium in the phase diagram. In addition, the gravimetric efficiency is calculated to identify coating materials that can eliminate Li residues with a minimal weight of the coating material. Overall, more MP and MO materials react with LiOH than with Li 2 CO 3 . Specifically, MPs exhibit better reactivity to both Li residues, whereas MOs react more with LiOH. The reaction products, such as Li-containing phosphates or oxides, are also obtained to identify the phases on the surface of a cathode after coating. On the basis of the Pareto-front analysis, P 2 O 5 could be an optimal material for the reaction with both Li residuals. Finally, the reactivity of the coating materials containing 3d/4d transition metal elements is better than that of materials containing other types of elements.

  16. Oxide-cathode activation and surface temperature calculation of electron cooler

    International Nuclear Information System (INIS)

    Li Jie; Yang Xiaodong; Mao Lijun; Li Guohong; Yuan Youjin; Liu Zhanwen; Zhang Junhui; Yang Xiaotian; Ma Xiaoming; Yan Tailai

    2011-01-01

    The pollution on electron gun ceramic insulation of electron cooler restricted the operation of electron cooler at HIRFL-CSR main ring. To cool and accumulate ion beam well, the pollution was cleared and a new oxide-coated cathode was assembled. The processes of cathode replacement,vacuum chamber baking-out, and thermal decomposition of coating binders and alkaline earth metal carbonates, and cathode activation are presented. The electron gun perveance of 10.6 μA/V 1.5 was attained under the heating power of 60 W. The typical surface temperature of oxide-coated cathode that is calculated through grey-body radiation is 1 108 K which shows a comparable result to the experimental measurement 1 078 K. The perveance growth of electron gun during the electron cooler operation is also explained by partial activation of the cathode. (authors)

  17. Redox?Reversible Iron Orthovanadate Cathode for Solid Oxide Steam Electrolyzer

    OpenAIRE

    Gan, Lizhen; Ye, Lingting; Ruan, Cong; Chen, Shigang; Xie, Kui

    2015-01-01

    A redox?reversible iron orthovanadate cathode is demonstrated for a solid oxide electrolyser with up to 100% current efficiency for steam electrolysis. The iron catalyst is grown on spinel?type electronic conductor FeV2O4 by in situ tailoring the reversible phase change of FeVO4 to Fe+FeV2O4 in a reducing atmosphere. Promising electrode performances have been obtained for a solid oxide steam electrolyser based on this composite cathode.

  18. Direct regeneration of recycled cathode material mixture from scrapped LiFePO4 batteries

    Science.gov (United States)

    Li, Xuelei; Zhang, Jin; Song, Dawei; Song, Jishun; Zhang, Lianqi

    2017-03-01

    A new green recycling process (named as direct regeneration process) of cathode material mixture from scrapped LiFePO4 batteries is designed for the first time. Through this direct regeneration process, high purity cathode material mixture (LiFePO4 + acetylene black), anode material mixture (graphite + acetylene black) and other by-products (shell, Al foil, Cu foil and electrolyte solvent, etc.) are recycled from scrapped LiFePO4 batteries with high yield. Subsequently, recycled cathode material mixture without acid leaching is further directly regenerated with Li2CO3. Direct regeneration procedure of recycled cathode material mixture from 600 to 800 °C is investigated in detail. Cathode material mixture regenerated at 650 °C display excellent physical, chemical and electrochemical performances, which meet the reuse requirement for middle-end Li-ion batteries. The results indicate the green direct regeneration process with low-cost and high added-value is feasible.

  19. Deposition of indium tin oxide thin films by cathodic arc ion plating

    International Nuclear Information System (INIS)

    Yang, M.-H.; Wen, J.-C.; Chen, K.-L.; Chen, S.-Y.; Leu, M.-S.

    2005-01-01

    Indium tin oxide (ITO) thin films have been deposited by cathodic arc ion plating (CAIP) using sintered oxide target as the source material. In an oxygen atmosphere of 200 deg. C, ITO films with a lowest resistivity of 2.2x10 -4 Ω-cm were obtained at a deposition rate higher than 450 nm/min. The carrier mobility of ITO shows a maximum at some medium pressures. Although morphologically ITO films with a very fine nanometer-sized structure were observed to possess the lowest resistivity, more detailed analyses based on X-ray diffraction are attempted to gain more insight into the factors that govern electron mobility in this investigation

  20. On the Properties and Long-Term Stability of Infiltrated Lanthanum Cobalt Nickelates (LCN) in Solid Oxide Fuel Cell Cathodes

    DEFF Research Database (Denmark)

    Kiebach, Wolff-Ragnar; Zielke, Philipp; Veltzé, Sune

    2017-01-01

    Infiltration as a fabrication method for solid oxide fuel cells (SOFC) electrodes is offering significant improvements in cell performance at reduced materials and fabrication costs, especially when combined with co-sintering. However, important questions regarding the long-term performance...... and microstructural stability remain unanswered. Here, we present the results of a three-year project, where large footprint anode-supported SOFCs with a co-sintered cathode backbone and infiltrated La0.95Co0.4Ni0.6O3 (LCN) cathodes were developed and thoroughly characterized. The initial long-term performance...... in the electrode properties using SEM, BET area, and in-plane conductivity measurements. Finally, the mechanical properties of co-sintered cathode backbone cells were determined in four-point bending tests carried out both at room temperature and at 800°C in air. Based on these results, degradation mechanisms were...

  1. Cation-substituted spinel oxide and oxyfluoride cathodes for lithium ion batteries

    Science.gov (United States)

    Manthiram, Arumugam; Choi, Wonchang

    2010-05-18

    The present invention includes compositions and methods of making cation-substituted and fluorine-substituted spinel cathode compositions by firing a LiMn2-y-zLiyMzO4 oxide with NH4HF2 at low temperatures of between about 300 and 700.degree. C. for 2 to 8 hours and a .eta. of more than 0 and less than about 0.50, mixed two-phase compositions consisting of a spinel cathode and a layered oxide cathode, and coupling them with unmodified or surface modified graphite anodes in lithium ion cells.

  2. The cathodic reduction of dioxygen on uranium oxide in dilute alkaline aqueous solution

    International Nuclear Information System (INIS)

    Hocking, W.H.; Betteridge, J.S.; Shoesmith, D.W.

    1991-09-01

    The cathodic reduction of dioxygen on uranium oxide in dilute alkaline aqueous solutions has been investigated within the context of a program to develop a comprehensive model to predict the behaviour of used CANDU (Canada Deuterium Uranium) nuclear fuel under disposal-vault conditions. Two different kinds of ceramic UO 2 were studied: reactor-grade CANDU fuel with normal p-type electrical conductivity and low-resistance material that exhibits n-type photoelectrochemical behaviour. The transport of electroactive species in solution was controlled by varying the rotation rate of rotating disc electrodes (RDE) and rotating ring-disc electrodes (RRDE). Steady-state polarization measurements were made using the current-interrupt method to compensate for the potential drop caused by ohmic resistance. Any release of peroxide to solution from the UO 2 (disc) surface could be monitored by oxidizing it at the Au ring of an RRDE. The existing theory for the cathodic 0 2 -reduction process as applied to RDE and RRDE experiments has been reviewed as a starting point for the interpretation of the results obtained in our work. (37 figs., 2 tabs., 170 refs.)

  3. Some peculiarities of thermoemission of the cathodes on the base of tanthanum and yttrium oxides

    International Nuclear Information System (INIS)

    Podgornyj, V.I.

    1982-01-01

    Thermoemission cathode characteristics on the basis of (La 2 O 3 ) lanthanum, and yttrium oxides which are used already in prctice but emission mechanism of which remains yet insufficiently elucidated, were investigated. It is shown that the heating of cathodes on the basis of Y 2 O 3 and La 2 O 3 at activation temperatures during 2-3 h with successive cooling results in the state of surface with increased thermoemission activity. It is established that the cathode heating in electric field of positive polarity results in decreasing thermoemission activity of lanthanum oxide by approximately 0.35 eV and for yttrium oxide - by approximately 0.05 eV as compared with the heating in the field of negative polarity. The effect obtained is related to the change in the metal adatom concentration on the cathode surface

  4. In situ green synthesis of MnFe_2O_4/reduced graphene oxide nanocomposite and its usage for fabricating high-performance LiMn_1_/_3Fe_2_/_3PO_4/reduced graphene oxide/carbon cathode material for Li-ion batteries

    International Nuclear Information System (INIS)

    Wu, Kaipeng; Hu, Guorong; Peng, Zhongdong; Cao, Yanbing; Du, Ke

    2016-01-01

    Highlights: • MnFe_2O_4/rGO was prepared by an in situ green reduction-coprecipitation method. • LiMn_1_/_3Fe_2_/_3PO_4/rGO/C was synthesized by using MnFe_2O_4/rGO as precursor. • Both pyrolytic carbon and rGO could construct an interconnected conductive network. • LiMn_1_/_3Fe_2_/_3PO_4/rGO/C shows excellent electrochemical performance. - Abstract: MnFe_2O_4/reduced graphene oxide nanocomposite (MnFe_2O_4/rGO) has been synthesized via a green reduction-coprecipitation method for the first time, which involved in situ reduction of GO in presence of Fe"2"+ and the ensuing coprecipitation of Fe"3"+ and Mn"2"+ onto the surface of rGO. The resultant MnFe_2O_4/rGO was then employed as the precursor to fabricate LiMn_1_/_3Fe_2_/_3PO_4/reduced graphene oxide/carbon composite (LiMn_1_/_3Fe_2_/_3PO_4/rGO/C) cathode material for Li-ion batteries. The composite consists of homogeneous Mn-Fe distributed LiMn_1_/_3Fe_2_/_3PO_4 with its primary particles (∼200 nm) covered and connected by both pyrolytic carbon and rGO sheets, which could prevent the aggregation of the particles as well as construct an interconnected conductive network for rapid transmission of electrons during charging and discharging process. The fabricated LiMn_1_/_3Fe_2_/_3PO_4/rGO/C can deliver a discharge capacity of 94.8 mAh g"−"1 even at the high rate of 20C, and shows a capacity decay rate of only 6.25% after 900 long-term charge-discharge cycles. Moreover, the proposed synthesis strategy can also be applied to prepare other graphene-decorated multi-component cathode/anode materials for the Li-ion batteries.

  5. Highly stable aqueous zinc-ion storage using a layered calcium vanadium oxide bronze cathode

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Chuan; Guo, Jing; Li, Peng; Zhang, Xixiang; Alshareef, Husam N. [Materials Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal (Saudi Arabia)

    2018-04-03

    Cost-effective aqueous rechargeable batteries are attractive alternatives to non-aqueous cells for stationary grid energy storage. Among different aqueous cells, zinc-ion batteries (ZIBs), based on Zn{sup 2+} intercalation chemistry, stand out as they can employ high-capacity Zn metal as the anode material. Herein, we report a layered calcium vanadium oxide bronze as the cathode material for aqueous Zn batteries. For the storage of the Zn{sup 2+} ions in the aqueous electrolyte, we demonstrate that the calcium-based bronze structure can deliver a high capacity of 340 mA h g{sup -1} at 0.2 C, good rate capability, and very long cycling life (96 % retention after 3000 cycles at 80 C). Further, we investigate the Zn{sup 2+} storage mechanism, and the corresponding electrochemical kinetics in this bronze cathode. Finally, we show that our Zn cell delivers an energy density of 267 W h kg{sup -1} at a power density of 53.4 W kg{sup -1}. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Recycling of spent lithium-ion battery cathode materials by ammoniacal leaching

    International Nuclear Information System (INIS)

    Ku, Heesuk; Jung, Yeojin; Jo, Minsang; Park, Sanghyuk; Kim, Sookyung; Yang, Donghyo; Rhee, Kangin; An, Eung-Mo; Sohn, Jeongsoo; Kwon, Kyungjung

    2016-01-01

    Highlights: • Ammoniacal leaching is used to recover spent Li-ion battery cathode materials. • Leaching agents consist of ammonia, ammonium sulfite and ammonium carbonate. • Ammonium sulfite is a reductant and ammonium carbonate acts as pH buffer. • Co and Cu can be fully leached while Mn and Al are not leached. • Co recovery via ammoniacal leaching is economical compared to acid leaching. - Abstract: As the production and consumption of lithium ion batteries (LIBs) increase, the recycling of spent LIBs appears inevitable from an environmental, economic and health viewpoint. The leaching behavior of Ni, Mn, Co, Al and Cu from treated cathode active materials, which are separated from a commercial LIB pack in hybrid electric vehicles, is investigated with ammoniacal leaching agents based on ammonia, ammonium carbonate and ammonium sulfite. Ammonium sulfite as a reductant is necessary to enhance leaching kinetics particularly in the ammoniacal leaching of Ni and Co. Ammonium carbonate can act as a pH buffer so that the pH of leaching solution changes little during leaching. Co and Cu can be fully leached out whereas Mn and Al are hardly leached and Ni shows a moderate leaching efficiency. It is confirmed that the cathode active materials are a composite of LiMn_2O_4, LiCo_xMn_yNi_zO_2_, Al_2O_3 and C while the leach residue is composed of LiNi_xMn_yCo_zO_2, LiMn_2O_4, Al_2O_3, MnCO_3 and Mn oxides. Co recovery via the ammoniacal leaching is believed to gain a competitive edge on convenitonal acid leaching both by reducing the sodium hydroxide expense for increasing the pH of leaching solution and by removing the separation steps of Mn and Al.

  7. GITT studies on oxide cathode LiNi1/3Co1/3Mn1/3O2 synthesized ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... GITT studies on oxide cathode LiNi1/3Co1/3Mn1/3O2 synthesized by citric acid assisted high-energy ball milling ... The State Key Laboratory Base of Novel Functional Materials and Preparation Science; The Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, P. R. ...

  8. Synthesis and characterization of cathode, anode and electrolyte materials for rechargeable lithium batteries

    Science.gov (United States)

    Yang, Shoufeng

    Two new classes of cathode materials were studied: iron phosphate/sulfate materials and layered manganese oxides, both of which are low cost and had shown some potential. The first class of materials have poor conductivity and cyclability. I studied a number of methods for increasing the conductivity, and determined that grinding the material with carbon black was as effective as special in-situ coatings. The optimum carbon loading was determined to be between 6 and 15 wt%. Too much carbon reduces the volumetric energy density, whereas too little significantly increased cell polarization (reduced the rate of reaction). The kinetic and thermodynamic stability of LiFePO 4 was also studied and it was determined that over discharge protection will be needed as irreversible Li3PO4 can be formed at low potentials. A novel hydrothermal synthesis method was developed, but the significant level of Fe on the Li site reduces the reaction rate too much. In the case of the layered manganese oxide, cation substitution with Co and Ni is found to be effective in avoiding Jahn-Teller effects and improving electrochemistry. A wide range of tin compounds have been suggested as lithium storage media for advanced anode materials, as tin can store over 4 Li per Sn atom. Lithium hexafluorophosphate, LiPF6, is presently the salt of choice for LiCoO2 batteries, but it is expensive and dissolves some manganese compounds. The lithium bis(oxolato)borate (BOB) salt was recently reported, and I made a study of its use in cells with the LiFePO4 cathode and the tin anode. During its synthesis, it became clear that LiBOB is very reactive with many solvents, and these complexes were characterized to better understand this new material. In LiBOB the lithium is five coordinated, an unstable configuration for the lithium ion so that water and many other solvents rapidly react to make a six coordination. Only in the case of ethylene carbonate was the lithium found to be four coordinated. The Li

  9. Performance and Structural Evolution of Nano-Scale Infiltrated Solid Oxide Fuel Cell Cathodes

    Science.gov (United States)

    Call, Ann Virginia

    Nano-structured mixed ionic and electronic conducting (MIEC) materials have garnered intense interest in electrode development for solid oxide fuel cells due to their high surface areas which allow for effective catalytic activity and low polarization resistances. In particular, composite solid oxide fuel cell (SOFC) cathodes consisting of ionic conducting scaffolds infiltrated with MIEC nanoparticles have exhibited some of the lowest reported polarization resistances. In order for cells utilizing nanostructured moRPhologies to be viable for commercial implementation, more information on their initial performance and long term stability is necessary. In this study, symmetric cell cathodes were prepared via wet infiltration of Sr0.5Sm 0.5CoO3 (SSC) nano-particles via a nitrate process into porous Ce0.9Gd0.1O1.95 (GDC) scaffolds to be used as a model system to investigate performance and structural evolution. Detailed analysis of the cells and cathodes was carried out using electrochemical impedance spectroscopy (EIS). Initial polarization resistances (RP) as low as 0.11 O cm2 at 600ºC were obtained for these SSC-GDC cathodes, making them an ideal candidate for studying high performance nano-structured electrodes. The present results show that the infiltrated cathode microstructure has a direct impact on the initial performance of the cell. Small initial particle sizes and high infiltration loadings (up to 30 vol% SSC) improved initial RP. A simple microstructure-based electrochemical model successfully explained these trends in RP. Further understanding of electrode performance was gleaned from fitting EIS data gathered under varying temperatures and oxygen partial pressures to equivalent circuit models. Both RQ and Gerischer impedance elements provided good fits to the main response in the EIS data, which was associated with the combination of oxygen surface exchange and oxygen diffusion in the electrode. A gas diffusion response was also observed at relatively

  10. La0.3Sr0.2Mn0.1Zn0.4 oxide-Sm0.2Ce0.8O1.9 (LSMZ-SDC) nanocomposite cathode for low temperature SOFCs.

    Science.gov (United States)

    Raza, Rizwan; Abbas, Ghazanfar; Liu, Qinghua; Patel, Imran; Zhu, Bin

    2012-06-01

    Nanocomposite based cathode materials compatible for low temperature solid oxide fuel cells (LTSOFCs) are being developed. In pursuit of compatible cathode, this research aims to synthesis and investigation nanocomposite La0.3Sr0.2Mn0.1Zn0.4 oxide-Sm0.2Ce0.8O1.9 (LSMZ-SDC) based system. The material was synthesized through wet chemical method and investigated for oxide-ceria composite based electrolyte LTSOFCs. Electrical property was studied by AC electrochemical impedance spectroscopy (EIS). The microstructure, thermal properties, and elemental analysis of the samples were characterized by TGA/DSC, XRD, SEM, respectively. The AC conductivity of cathode was obtained for 2.4 Scm(-1) at 550 degrees C in air. This cathode is compatible with ceria-based composite electrolytes and has improved the stability of the material in SOFC cathode environment.

  11. Synthesis of V2O5 microspheres by spray pyrolysis as cathode material for supercapacitors

    Science.gov (United States)

    Yin, Zhendong; Xu, Jie; Ge, Yali; Jiang, Qiaoya; Zhang, Yaling; Yang, Yawei; Sun, Yuping; Hou, Siyu; Shang, Yuanyuan; Zhang, Yingjiu

    2018-03-01

    Vanadium oxide (V2O5) microspheres have attracted considerable attention in the energy field due to their unique properties such as high stability and electrochemical activity. Here, massive V2O5 microspheres with smooth surface, hollow cavity and uniform particle sizes (0.4–1.5 μm), were synthesized by a facile spray pyrolysis process. Post-treatment at predefined temperatures effectively turned the microsphere shell into stacked nanorods with widths of 100 nm and lengths of 500 nm when processed at 500 °C for 3 h under nitrogen atmosphere, with enhanced crystallinity. When applied as cathode materials for supercapacitors, the post-treated V2O5 microspheres at 500 °C exhibited improved specific capacitance and longer discharge time. This is an effective method to manufacture massive V2O5 microspheres with tailored structure and potential applications in high-performance energy storage materials.

  12. High energy density asymmetric supercapacitors with a nickel oxide nanoflake cathode and a 3D reduced graphene oxide anode

    Science.gov (United States)

    Luan, Feng; Wang, Gongming; Ling, Yichuan; Lu, Xihong; Wang, Hanyu; Tong, Yexiang; Liu, Xiao-Xia; Li, Yat

    2013-08-01

    Here we demonstrate a high energy density asymmetric supercapacitor with nickel oxide nanoflake arrays as the cathode and reduced graphene oxide as the anode. Nickel oxide nanoflake arrays were synthesized on a flexible carbon cloth substrate using a seed-mediated hydrothermal method. The reduced graphene oxide sheets were deposited on three-dimensional (3D) nickel foam by hydrothermal treatment of nickel foam in graphene oxide solution. The nanostructured electrodes provide a large effective surface area. The asymmetric supercapacitor device operates with a voltage of 1.7 V and achieved a remarkable areal capacitance of 248 mF cm-2 (specific capacitance of 50 F g-1) at a charge/discharge current density of 1 mA cm-2 and a maximum energy density of 39.9 W h kg-1 (based on the total mass of active materials of 5.0 mg). Furthermore, the device showed an excellent charge/discharge cycling performance in 1.0 M KOH electrolyte at a current density of 5 mA cm-2, with a capacitance retention of 95% after 3000 cycles.

  13. High energy density asymmetric supercapacitors with a nickel oxide nanoflake cathode and a 3D reduced graphene oxide anode.

    Science.gov (United States)

    Luan, Feng; Wang, Gongming; Ling, Yichuan; Lu, Xihong; Wang, Hanyu; Tong, Yexiang; Liu, Xiao-Xia; Li, Yat

    2013-09-07

    Here we demonstrate a high energy density asymmetric supercapacitor with nickel oxide nanoflake arrays as the cathode and reduced graphene oxide as the anode. Nickel oxide nanoflake arrays were synthesized on a flexible carbon cloth substrate using a seed-mediated hydrothermal method. The reduced graphene oxide sheets were deposited on three-dimensional (3D) nickel foam by hydrothermal treatment of nickel foam in graphene oxide solution. The nanostructured electrodes provide a large effective surface area. The asymmetric supercapacitor device operates with a voltage of 1.7 V and achieved a remarkable areal capacitance of 248 mF cm(-2) (specific capacitance of 50 F g(-1)) at a charge/discharge current density of 1 mA cm(-2) and a maximum energy density of 39.9 W h kg(-1) (based on the total mass of active materials of 5.0 mg). Furthermore, the device showed an excellent charge/discharge cycling performance in 1.0 M KOH electrolyte at a current density of 5 mA cm(-2), with a capacitance retention of 95% after 3000 cycles.

  14. Mathematical micro-model of a solid oxide fuel cell composite cathode

    International Nuclear Information System (INIS)

    Kenney, B.; Karan, K.

    2004-01-01

    In a solid oxide fuel cell (SOFC), the cathode processes account for a majority of the overall electrochemical losses. A composite cathode comprising a mixture of ion-conducting electrolyte and electron-conducting electro-catalyst can help minimize cathode losses provided microstructural parameters such as particle-size, composition, and porosity are optimized. The cost of composite cathode research can be greatly reduced by incorporating mathematical models into the development cycle. Incorporated with reliable experimental data, it is possible to conduct a parametric study using a model and the predicted results can be used as guides for component design. Many electrode models treat the cathode process simplistically by considering only the charge-transfer reaction for low overpotentials or the gas-diffusion at high overpotentials. Further, in these models an average property of the cathode internal microstructure is assumed. This paper will outline the development of a 1-dimensional SOFC composite cathode micro-model and the experimental procedures for obtaining accurate parameter estimates. The micro-model considers the details of the cathode microstructure such as porosity, composition and particle-size of the ionic and electronic phases, and their interrelationship to the charge-transfer reaction and mass transport processes. The micro-model will be validated against experimental data to determine its usefulness for performance prediction. (author)

  15. Interaction of Ni-Re and Ni-W alloys with residual gases and carbonates under working conditions of oxide cathodes of electronic vacuum instrumentation

    International Nuclear Information System (INIS)

    Arskaya, E.P.; Korotkov, N.A.; Lazarev, Eh.M.

    1979-01-01

    Using the method of th micro X-ray spectrum, electron diffraction, micro X-ray spectrum and electron probe analysis and measuring the microhardness, the composition and structure of the zone, in which Ni-W-La and Ni-Re-La alloy core samples contact the oxide coating, have been studied. Analyzed was the significance of the diffusion processes, occurring dUring the continuous operation of oxide cathodes at increased temperatures. The diffusion constants of the Ni-W system in the temperature range of the oxide cathodes operation have been determined. It is shown that during the continuous operation of electrovaccuum instruments (10.000 hrs), Ni-Re alloys should be used as oxide cathode core sample materials, as they maintain their shape well and possess good electrophysical and emission characteristics

  16. Optimization of Layered Cathode Materials for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Christian Julien

    2016-07-01

    Full Text Available This review presents a survey of the literature on recent progress in lithium-ion batteries, with the active sub-micron-sized particles of the positive electrode chosen in the family of lamellar compounds LiMO2, where M stands for a mixture of Ni, Mn, Co elements, and in the family of yLi2MnO3•(1 − yLiNi½Mn½O2 layered-layered integrated materials. The structural, physical, and chemical properties of these cathode elements are reported and discussed as a function of all the synthesis parameters, which include the choice of the precursors and of the chelating agent, and as a function of the relative concentrations of the M cations and composition y. Their electrochemical properties are also reported and discussed to determine the optimum compositions in order to obtain the best electrochemical performance while maintaining the structural integrity of the electrode lattice during cycling.

  17. Particle size effect of Ni-rich cathode materials on lithium ion battery performance

    International Nuclear Information System (INIS)

    Hwang, Ilkyu; Lee, Chul Wee; Kim, Jae Chang; Yoon, Songhun

    2012-01-01

    Graphical abstract: The preparation condition of Ni-rich cathode materials was investigated. When the retention time was short, a poor cathode performance was observed. For long retention time condition, cathode performance displayed a best result at pH 12. Highlights: ► Ni-rich cathode materials (LiNi 0.8 Co 0.15 Al 0.05 O 2 ) were prepared by co-precipitation method using separate addition of Al salt. ► Particle size of Ni-rich cathode materials became larger with increase of retention time and solution pH. ► Cathode performance was poor for low retention time. ► Optimal pH for co-precipitation was 12. -- Abstract: Herein, Ni-rich cathode materials (LiNi 0.8 Co 0.15 Al 0.05 O 2 ) in lithium ion batteries are prepared by a separate addition of Ni/Co salt and Al sol solution using a continuously stirred tank reactor. Retention time and solution pH were controlled in order to obtain high performance cathode material. Particle size increase was observed with a higher retention time of the reactants. Also, primary and secondary particles became smaller according to an increase of solution pH, which was probably due to a decrease of growth rate. From the cathode application, a high discharge capacity (175 mAh g −1 ), a high initial efficiency (90%) and a good cycleability were observed in the cathode material prepared under pH 12 condition, which was attributed to its well-developed layered property and the optimal particle size. However, rate capability was inversely proportional to the particle size, which was clarified by a decrease of charge-transfer resistance measured in the electrochemical impedance spectroscopy.

  18. Recycling of spent lithium-ion battery cathode materials by ammoniacal leaching.

    Science.gov (United States)

    Ku, Heesuk; Jung, Yeojin; Jo, Minsang; Park, Sanghyuk; Kim, Sookyung; Yang, Donghyo; Rhee, Kangin; An, Eung-Mo; Sohn, Jeongsoo; Kwon, Kyungjung

    2016-08-05

    As the production and consumption of lithium ion batteries (LIBs) increase, the recycling of spent LIBs appears inevitable from an environmental, economic and health viewpoint. The leaching behavior of Ni, Mn, Co, Al and Cu from treated cathode active materials, which are separated from a commercial LIB pack in hybrid electric vehicles, is investigated with ammoniacal leaching agents based on ammonia, ammonium carbonate and ammonium sulfite. Ammonium sulfite as a reductant is necessary to enhance leaching kinetics particularly in the ammoniacal leaching of Ni and Co. Ammonium carbonate can act as a pH buffer so that the pH of leaching solution changes little during leaching. Co and Cu can be fully leached out whereas Mn and Al are hardly leached and Ni shows a moderate leaching efficiency. It is confirmed that the cathode active materials are a composite of LiMn2O4, LiCoxMnyNizO2, Al2O3 and C while the leach residue is composed of LiNixMnyCozO2, LiMn2O4, Al2O3, MnCO3 and Mn oxides. Co recovery via the ammoniacal leaching is believed to gain a competitive edge on convenitonal acid leaching both by reducing the sodium hydroxide expense for increasing the pH of leaching solution and by removing the separation steps of Mn and Al. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Comprehensive Enhancement of Nanostructured Lithium-Ion Battery Cathode Materials via Conformal Graphene Dispersion.

    Science.gov (United States)

    Chen, Kan-Sheng; Xu, Rui; Luu, Norman S; Secor, Ethan B; Hamamoto, Koichi; Li, Qianqian; Kim, Soo; Sangwan, Vinod K; Balla, Itamar; Guiney, Linda M; Seo, Jung-Woo T; Yu, Xiankai; Liu, Weiwei; Wu, Jinsong; Wolverton, Chris; Dravid, Vinayak P; Barnett, Scott A; Lu, Jun; Amine, Khalil; Hersam, Mark C

    2017-04-12

    Efficient energy storage systems based on lithium-ion batteries represent a critical technology across many sectors including consumer electronics, electrified transportation, and a smart grid accommodating intermittent renewable energy sources. Nanostructured electrode materials present compelling opportunities for high-performance lithium-ion batteries, but inherent problems related to the high surface area to volume ratios at the nanometer-scale have impeded their adoption for commercial applications. Here, we demonstrate a materials and processing platform that realizes high-performance nanostructured lithium manganese oxide (nano-LMO) spinel cathodes with conformal graphene coatings as a conductive additive. The resulting nanostructured composite cathodes concurrently resolve multiple problems that have plagued nanoparticle-based lithium-ion battery electrodes including low packing density, high additive content, and poor cycling stability. Moreover, this strategy enhances the intrinsic advantages of nano-LMO, resulting in extraordinary rate capability and low temperature performance. With 75% capacity retention at a 20C cycling rate at room temperature and nearly full capacity retention at -20 °C, this work advances lithium-ion battery technology into unprecedented regimes of operation.

  20. High-Current Cold Cathode Employing Diamond and Related Materials

    Energy Technology Data Exchange (ETDEWEB)

    Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT (United States)

    2014-10-22

    The essence of this project was for diamond films to be deposited on cold cathodes to improve their emission properties. Films with varying morphology, composition, and size of the crystals were deposited and the emission properties of the cathodes that utilize such films were studied. The prototype cathodes fabricated by the methods developed during Phase I were tested and evaluated in an actual high-power RF device during Phase II. These high-power tests used the novel active RF pulse compression system and the X-band magnicon test facility at US Naval Research Laboratory. In earlier tests, plasma switches were employed, while tests under this project utilized electron-beam switching. The intense electron beams required in the switches were supplied from cold cathodes embodying diamond films with varying morphology, including uncoated molybdenum cathodes in the preliminary tests. Tests with uncoated molybdenum cathodes produced compressed X-band RF pulses with a peak power of 91 MW, and a maximum power gain of 16.5:1. Tests were also carried out with switches employing diamond coated cathodes. The pulse compressor was based on use of switches employing electron beam triggering to effect mode conversion. In experimental tests, the compressor produced 165 MW in a ~ 20 ns pulse at ~18× power gain and ~ 140 MW at ~ 16× power gain in a 16 ns pulse with a ~ 7 ns flat-top. In these tests, molybdenum blade cathodes with thin diamond coatings demonstrated good reproducible emission uniformity with a 100 kV, 100 ns high voltage pulse. The new compressor does not have the limitations of earlier types of active pulse compressors and can operate at significantly higher electric fields without breakdown.

  1. Model for solid oxide fuel cell cathodes prepared by infiltration

    DEFF Research Database (Denmark)

    Samson, Alfred Junio; Søgaard, Martin; Hendriksen, Peter Vang

    2017-01-01

    A 1-dimensional model of a cathode has been developed in order to understand and predict the performance of cathodes prepared by infiltration of La0.6Sr0.4Co1.05O3-δ (LSC) into porous backbones of Ce0.9Gd0.1O1.95 (CGO). The model accounts for the mixed ionic and electronic conductivity of LSC......, ionic conductivity of CGO, gas transport in the porous cathode, and the oxygen reduction reaction at the surface of percolated LSC. Geometrical variations are applied to reflect a changing microstructure of LSC under varying firing temperatures. Using microstructural parameters obtained from detailed...... scanning electron microscopy and simulations of the measured polarization resistances, an expression for the area specific resistance (rp) associated with the oxygen exchange on the surface of the infiltrated LSC particles was extracted and compared with literature values. A series of microstructural...

  2. Effect of Metal (Mn, Ti) Doping on NCA Cathode Materials for Lithium Ion Batteries

    OpenAIRE

    Wan, Dao Yong; Fan, Zhi Yu; Dong, Yong Xiang; Baasanjav, Erdenebayar; Jun, Hang-Bae; Jin, Bo; Jin, En Mei; Jeong, Sang Mun

    2018-01-01

    NCA (LiNi0.85Co0.10Al0.05-x MxO2, M=Mn or Ti, x < 0.01) cathode materials are prepared by a hydrothermal reaction at 170°C and doped with Mn and Ti to improve their electrochemical properties. The crystalline phases and morphologies of various NCA cathode materials are characterized by XRD, FE-SEM, and particle size distribution analysis. The CV, EIS, and galvanostatic charge/discharge test are employed to determine the electrochemical properties of the cathode materials. Mn and Ti doping res...

  3. Effect of Cobalt Content on the Electrochemical Properties and Structural Stability of NCA Type Cathode Materials

    OpenAIRE

    Ghatak, Kamalika; Basu, Swastik; Das, Tridip; Kumar, Hemant; Datta, Dibakar

    2018-01-01

    At present, the most common type of cathode materials, NCA [Li_(1-x)Ni_(0.80)Co_(0.15)Al_(0.05)O_(2), x = 0 to 1], have a very high concentration of cobalt. Since cobalt is toxic and expensive, the existing design of cathode materials is neither cost-effective nor environmentally benign. We have performed density functional theory (DFT) calculations to investigate electrochemical, electronic, and structural properties of four types of NCA cathode materials with the simultaneous decrease in Co...

  4. Surface and bulk modified high capacity layered oxide cathodes with low irreversible capacity loss

    Science.gov (United States)

    Manthiram, Arumugam (Inventor); Wu, Yan (Inventor)

    2010-01-01

    The present invention includes compositions, surface and bulk modifications, and methods of making of (1-x)Li[Li.sub.1/3Mn.sub.2/3]O.sub.2.xLi[Mn.sub.0.5-yNi.sub.0.5-yCo.sub.2- y]O.sub.2 cathode materials having an O3 crystal structure with a x value between 0 and 1 and y value between 0 and 0.5, reducing the irreversible capacity loss in the first cycle by surface modification with oxides and bulk modification with cationic and anionic substitutions, and increasing the reversible capacity to close to the theoretical value of insertion/extraction of one lithium per transition metal ion (250-300 mAh/g).

  5. Electrochemical performance of polypyrrole/silver vanadium oxide composite cathodes in lithium primary batteries

    Science.gov (United States)

    Anguchamy, Yogesh K.; Lee, Jong-Won; Popov, Branko N.

    Polypyrrole (PPy)/silver vanadium oxide (SVO) composite cathode materials were synthesized by polymerizing pyrrole onto the surface of pure SVO particles. Electrochemical characterization was carried out by performing galvanostatic discharge, pulse discharge and ac-impedance experiments. The composite electrode exhibited better performance than pristine SVO in all the experiments. The composite electrodes yielded a higher discharge capacity and a better pulse discharge capability when compared to the pristine SVO electrode. The pulse discharge and ac-impedance studies indicated that PPy forms an effective conductive network on the SVO surface and thereby reduces the particle-to-particle contact resistance and facilitates the interfacial charge transfer kinetics. To determine the thermal stability of the composite cathode, galvanostatic discharge and ac-impedance experiments were performed at different temperatures. The capacity increased with temperature due to enhanced charge transfer kinetics and low mass transfer limitations. The peak capacity was obtained at 60 °C, after which the performance degraded with any further increase in temperature.

  6. Electrochemical performance of polypyrrole/silver vanadium oxide composite cathodes in lithium primary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Anguchamy, Yogesh K.; Lee, Jong-Won; Popov, Branko N. [Center for Electrochemical Engineering, Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2008-09-15

    Polypyrrole (PPy)/silver vanadium oxide (SVO) composite cathode materials were synthesized by polymerizing pyrrole onto the surface of pure SVO particles. Electrochemical characterization was carried out by performing galvanostatic discharge, pulse discharge and ac-impedance experiments. The composite electrode exhibited better performance than pristine SVO in all the experiments. The composite electrodes yielded a higher discharge capacity and a better pulse discharge capability when compared to the pristine SVO electrode. The pulse discharge and ac-impedance studies indicated that PPy forms an effective conductive network on the SVO surface and thereby reduces the particle-to-particle contact resistance and facilitates the interfacial charge transfer kinetics. To determine the thermal stability of the composite cathode, galvanostatic discharge and ac-impedance experiments were performed at different temperatures. The capacity increased with temperature due to enhanced charge transfer kinetics and low mass transfer limitations. The peak capacity was obtained at 60 C, after which the performance degraded with any further increase in temperature. (author)

  7. LaNi1-xCoxO3-δ (x=0.4 to 0.7) cathodes for solid oxide fuel cells by infiltration

    Science.gov (United States)

    Chrzan, Aleksander; Ovtar, Simona; Chen, Ming

    2016-01-01

    Performance of LaNi1-xCoxO3-δ (LNC) (x=0.4 to 0.7) as a cathode in solid oxide fuel cell (SOFC) is evaluated. Symmetrical cathode/electrolyte/cathode cells for electrochemical testing are prepared by infiltration of yttria stabilized zirconia (YSZ) backbone with LNC solutions. It is showed that the cathode infiltrated with LaNi0.5Co0.5O3-δ (LNC155) has the lowest polarization resistance and activation energy, 197 mΩ cm2 at 600 °C and 0.91 eV, respectively. Therefore it is the most promising material of the LNC group for electrochemical applications. X-ray diffraction analysis revealed that none of the materials is single-phased after heat treatment at 800 °C as they contain residues of La2O3 and La2NiO4-δ

  8. Impregnation of LSM Based Cathodes for Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Højberg, Jonathan; Søgaard, Martin

    2011-01-01

    Composites cathodes consisting of strontium doped lanthanum manganite (LSM) and yttria stabilized zirconia have been impregnated with the nitrates corresponding to the nominal compositions: La0.75Sr0.25Mn1.05O3 +/-delta (LSM25), Ce0.8Sm0.2O2 (SDC) and a combination of both (dual). The latter...

  9. Advanced carbon materials/olivine LiFePO4 composites cathode for lithium ion batteries

    Science.gov (United States)

    Gong, Chunli; Xue, Zhigang; Wen, Sheng; Ye, Yunsheng; Xie, Xiaolin

    2016-06-01

    In the past two decades, LiFePO4 has undoubtly become a competitive candidate for the cathode material of the next-generation LIBs due to its abundant resources, low toxicity and excellent thermal stability, etc. However, the poor electronic conductivity as well as low lithium ion diffusion rate are the two major drawbacks for the commercial applications of LiFePO4 especially in the power energy field. The introduction of highly graphitized advanced carbon materials, which also possess high electronic conductivity, superior specific surface area and excellent structural stability, into LiFePO4 offers a better way to resolve the issue of limited rate performance caused by the two obstacles when compared with traditional carbon materials. In this review, we focus on advanced carbon materials such as one-dimensional (1D) carbon (carbon nanotubes and carbon fibers), two-dimensional (2D) carbon (graphene, graphene oxide and reduced graphene oxide) and three-dimensional (3D) carbon (carbon nanotubes array and 3D graphene skeleton), modified LiFePO4 for high power lithium ion batteries. The preparation strategies, structure, and electrochemical performance of advanced carbon/LiFePO4 composite are summarized and discussed in detail. The problems encountered in its application and the future development of this composite are also discussed.

  10. Advanced Cathode Material For High Energy Density Lithium-Batteries, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced cathode materials having high red-ox potential and high specific capacity offer great promise to the development of high energy density lithium-based...

  11. Factors Affecting the Battery Performance of Anthraquinone-based Organic Cathode Materials

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wu; Read, Adam L.; Koech, Phillip K.; Hu, Dehong; Wang, Chong M.; Xiao, Jie; Padmaperuma, Asanga B.; Graff, Gordon L.; Liu, Jun; Zhang, Jiguang

    2012-02-01

    Two organic cathode materials based on poly(anthraquinonyl sulfide) structure with different substitution positions were synthesized and their electrochemical behavior and battery performances were investigated. The substitution positions on the anthraquinone structure, binders for electrode preparation and electrolyte formulations have been found to have significant effects on the battery performances of such organic cathode materials. The substitution position with less steric stress has higher capacity, longer cycle life and better high-rate capability. Polyvinylidene fluoride binder and ether-based electrolytes are favorable for the high capacity and long cycle life of the quinonyl organic cathodes.

  12. Microstructure and emission ability of rare earth oxides doped molybdenum cathodes

    International Nuclear Information System (INIS)

    Yang Jiancan; Nie Zuoren; Wang Yiman

    2003-01-01

    We adopted high-resolution transmission electron microscopy (TEM) and scanning electron microscopy (SAM) to observe and analyze the microstructure of rare earth oxide (La 2 O 3 , Sc 2 O 3 ) doped molybdenum cathodes. The results show that there are many nanometer particles in the molybdenum matrix besides some sub-micrometer particles in the crystal interfaces. All these particles are rare earth oxides as determined through calculating the electron diffraction pattern. Then we determined the electron work function and the zero-field emission current of molybdenum cathodes by the electron emission measurement. To correlate the emission data with surface composition, we use Auger electron spectroscopy (AES) to analyze the elements on the activated cathode surface and their depth profiles. We found that there were about 20 nm thick layers on an activated cathode surface, which have a high content of rare earth elements. We also use AES to analyze the elements diffusion to the cathode surface from cathode body during heating up to its operating temperature to find out which element positively affects the electron emission

  13. Graphitized Carbon: A Promising Stable Cathode Catalyst Support Material for Long Term PEMFC Applications.

    Science.gov (United States)

    Mohanta, Paritosh Kumar; Regnet, Fabian; Jörissen, Ludwig

    2018-05-28

    Stability of cathode catalyst support material is one of the big challenges of polymer electrolyte membrane fuel cells (PEMFC) for long term applications. Traditional carbon black (CB) supports are not stable enough to prevent oxidation to CO₂ under fuel cell operating conditions. The feasibility of a graphitized carbon (GC) as a cathode catalyst support for low temperature PEMFC is investigated herein. GC and CB supported Pt electrocatalysts were prepared via an already developed polyol process. The physical characterization of the prepared catalysts was performed using transmission electron microscope (TEM), X-ray Powder Diffraction (XRD) and inductively coupled plasma optical emission spectrometry (ICP-OES) analysis, and their electrochemical characterizations were conducted via cyclic voltammetry(CV), rotating disk electrode (RDE) and potential cycling, and eventually, the catalysts were processed using membrane electrode assemblies (MEA) for single cell performance tests. Electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SEM) have been used as MEA diagonostic tools. GC showed superior stability over CB in acid electrolyte under potential conditions. Single cell MEA performance of the GC-supported catalyst is comparable with the CB-supported catalyst. A correlation of MEA performance of the supported catalysts of different Brunauer⁻Emmett⁻Teller (BET) surface areas with the ionomer content was also established. GC was identified as a promising candidate for catalyst support in terms of both of the stability and the performance of fuel cell.

  14. Study on structural refinement and electrochemical behaviour of Ba0.5Sr0.5Co0.8Fe0.2O3-δ as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFC)

    Science.gov (United States)

    Kautkar, Pranay R.; Shirbhate, Shraddha C.; Acharya, Smita A.

    2018-05-01

    Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) was prepared by ethylene glycol-citrate combined sol-gel combustion route and calcined at optimized temperature 1050°C. The X-ray Diffraction (XRD) data revealing the crystal purity of BSCF cathode was refined by the Cubic-type structure having the space group Pm-3m by Rietveld analysis. Refined lattice parameter of BSCF cathode is a = 3.9759 Å and unit cell volume is 62.85 (4) Å3, Co/Fe-O bond length from VESTA program figured out to be 1.987 (3) Å. Electron density distribution (EDD) of the unit cell of BSCF cathode shows the bonding feature with oxygen ions, this could represent oxygen vacancies are present in the lattice. These results reflected in electrochemical impedance spectra measurement of symmetric cell. Area of specific resistance (ASR) of the BSCF cathode was found to be 0.17 Ω.cm2 at 700°C and respective activation energy (Ea) 1.15 eV. It shows surface exchange at cathode interface, surface diffusion and self-diffusion happened through Ce0.85Sd0.15O1.95 (SDC15) electrolyte.

  15. Graphene-Based Composites as Cathode Materials for Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Libao Chen

    2013-01-01

    Full Text Available Owing to the superior mechanical, thermal, and electrical properties, graphene was a perfect candidate to improve the performance of lithium ion batteries. Herein, we review the recent advances in graphene-based composites and their application as cathode materials for lithium ion batteries. We focus on the synthesis methods of graphene-based composites and the superior electrochemical performance of graphene-based composites as cathode materials for lithium ion batteries.

  16. Formation of an interface layer in thermionic oxide cathodes for CRT applications

    International Nuclear Information System (INIS)

    Hashim, A A; Barratt, D S; Ray, A K; Hassan, A K

    2004-01-01

    Scanning electron microscopic techniques were employed to study the surface morphological changes of oxide cathodes and nickel caps as a result of cathode activation extending over periods of 1-12 h. Elemental analysis of barium, strontium, tungsten, magnesium and aluminium was performed using energy dispersion x-ray spectroscopy. An abrupt change was observed after activation longer than 3 h. Conduction through well activated cathode assemblies was found to be due to intergranular electron tunnelling at low temperatures (T ≤ 500 K), while trapping and detrapping at grain boundaries becomes the dominant mechanism at high temperatures (T ≥ 500 K). The contribution of the interfacial layer to conductivity was found to be significant for cathodes activated for smaller periods

  17. Stability of solid oxide fuel cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.R.; Bates, J.L.; Coffey, G.W.; Pederson, L.R. [Pacific Northwest National Lab., Richland, WA (United States)] [and others

    1996-08-01

    Chromite interconnection materials in an SOFC are exposed to both highly oxidizing conditions at the cathode and to highly reducing conditions at the anode. Because such conditions could lead to component failure, the authors have evaluated thermal, electrical, chemical, and structural stabilities of these materials as a function of temperature and oxygen partial pressure. The crystal lattice of the chromites was shown to expand for oxygen partial pressures smaller than 10{sup {minus}10} atm, which could lead to cracking and debonding in an SOFC. Highly substituted lanthanum chromite compositions were the most susceptible to lattice expansion; yttrium chromites showed better dimensional stability by more than a factor of two. New chromite compositions were developed that showed little tendency for lattice expansion under strongly reducing conditions, yet provided a good thermal expansion match to other fuel cell components. Use of these new chromite interconnect compositions should improve long-term SOFC performance, particularly for planar cell configurations. Thermodynamic properties of substituted lanthanum manganite cathode compositions have been determined through measurement of electromotive force as a function of temperature. Critical oxygen decomposition pressures for Sr and Ca-substituted lanthanum manganites were established using cells based on a zirconia electrolyte. Strontium oxide and calcium oxide activities in a lanthanum manganite matrix were determined using cells based on strontium fluoride and calcium fluoride electrolytes, respectively. The compositional range of single-phase behavior of these ABO{sub 3}-type perovskites was established as a function of A/B cation ratios and the extent of acceptor doping. Before this work, very little thermodynamic information was in existence for substituted manganite compositions. Such information is needed to predict the long-term stability of solid oxide fuel cell assemblies.

  18. Nano Copper Oxide-Modified Carbon Cloth as Cathode for a Two-Chamber Microbial Fuel Cell

    OpenAIRE

    Dong, Feng; Zhang, Peng; Li, Kexun; Liu, Xianhua; Zhang, Pingping

    2016-01-01

    In this work, Cu2O nanoparticles were deposited on a carbon cloth cathode using a facile electrochemical method. The morphology of the modified cathode, which was characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) tests, showed that the porosity and specific surface area of the cathode improved with longer deposition times. X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) results showed that cupric oxide and cuprous oxide coexisted on the ca...

  19. Cathodic arc sputtering of functional titanium oxide thin films, demonstrating resistive switching

    Energy Technology Data Exchange (ETDEWEB)

    Shvets, Petr, E-mail: pshvets@innopark.kantiana.ru; Maksimova, Ksenia; Demin, Maxim; Dikaya, Olga; Goikhman, Alexander

    2017-05-15

    The formation of thin films of the different stable and metastable titanium oxide phases is demonstrated by cathode arc sputtering of a titanium target in an oxygen atmosphere. We also show that sputtering of titanium in vacuum yields the formation of titanium silicides on the silicon substrate. The crystal structure of the produced samples was investigated using Raman spectroscopy and X-ray diffraction. We conclude that cathode arc sputtering is a flexible method suitable for producing the functional films for electronic applications. The functionality is verified by the memory effect demonstration, based on the resistive switching in the titanium oxide thin film structure.

  20. High-resolution TEM microscopy study of the creep behaviour of carbon-based cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei, E-mail: wwlyzwkj@126.com [College of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023 (China); Collaborative Innovation Center of Nonferrous Metals Henan Province, Luoyang 471023 (China); Chen, Weijie [College of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023 (China); Collaborative Innovation Center of Nonferrous Metals Henan Province, Luoyang 471023 (China); Gu, Wanduo [Collaborative Innovation Center of Nonferrous Metals Henan Province, Luoyang 471023 (China)

    2017-02-27

    Creep is in close relationship with the materials deterioration and deformation of the cathodes in aluminum reduction cells. The purpose of this work is to obtain the creep mechanism of the carbon cathode for aluminum electrolysis. A modified Rapoport equipment was used for measuring the creep strain of the semi-graphitic cathodes during aluminum electrolysis with CR=2.5 and at temperature of 945 ℃. The arrangement of carbon atom has been studied after hexagonal graphite converting into rhombohedral graphite during aluminum electrolysis by XRD and high-resolution transmission electron microscopy (HRTEM). The creep deformation of the carbon cathode has a close relationship with the mobile dislocation walls. These results will be helpful in controlling the cathode quality and its performance in aluminum reduction cells.

  1. Synthesis and characterization of cobaltite nanotubes for solid-oxide fuel cell cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Napolitano, F; Baque, L; Troiani, H; Granada, M; Serquis, A, E-mail: aserquis@cab.cnea.gov.a [Instituto Balseiro-Centro Atomico Bariloche and CONICET, San Carlos de Bariloche (Argentina)

    2009-05-01

    La{sub 1-x}Sr{sub x}Co{sub 1-y}FeyO{sub 3-d}elta oxides are good candidates for solid oxide fuel cell (SOFC) cathodes because these materials present high ionic and electronic conductivity, and compatibility with Cerium Gadolinium Oxide (CGO) electrolytes allowing a lower operation temperature. In this work, we report the synthesis of La{sub 0.4}Sr{sub 0.6}Co{sub 0.8}Fe{sub 0.2}O{sub 3-d}elta (LSCF) nanotubes prepared by a porous polycarbonate membrane approach, obtaining different microstructures depending on sintering conditions. The structure and morphology of the nanotubes and deposited films were characterized by X-ray diffraction, transmission and scanning microscopy. Finally, we obtained nanostructured films of vertically aligned LSCF tubes deposited over the whole surface of CGO pellets with diameter up to 2.5cm in a direct and single step process.

  2. Comparative Issues of Cathode Materials for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Christian M. Julien

    2014-03-01

    Full Text Available After an introduction to lithium insertion compounds and the principles of Li-ion cells, we present a comparative study of the physical and electrochemical properties of positive electrodes used in lithium-ion batteries (LIBs. Electrode materials include three different classes of lattices according to the dimensionality of the Li+ ion motion in them: olivine, layered transition-metal oxides and spinel frameworks. Their advantages and disadvantages are compared with emphasis on synthesis difficulties, electrochemical stability, faradaic performance and security issues.

  3. Surface Modification Technique of Cathode Materials for LI-ION Battery

    Science.gov (United States)

    Jia, Yongzhong; Han, Jinduo; Jing, Yan; Jin, Shan; Qi, Taiyuan

    Cathode materials for Li-ion battery LiMn2O4 and LiCo0.1Mn1.9O4 were prepared by soft chemical method. Carbon, which was made by decomposing organic compounds, was used as modifying agent. Cathode material matrix was mixed with water solution that had contained organic compound such as cane sugar, soluble amylum, levulose et al. These mixture were reacted at 150 200 °C for 0.5 4 h in a Teflon-lined autoclave to get a series of homogeneously C-coated cathode materials. The new products were analyzed by X-ray diffraction (XRD) and infrared (IR). Morphology of cathode materials was characterized by scanning electron microscope (SEM) and transition electron microscope (TEM). The new homogeneously C-coated products that were used as cathode materials of lithium-ion battery had good electrochemical stability and cycle performance. This technique has free-pollution, low cost, simpleness and easiness to realize the industrialization of the cathode materials for Li-ion battery.

  4. Experimental investigation on the motion of cathode spots in removing oxide film on metal surface by vacuum arc

    International Nuclear Information System (INIS)

    Shi Zongqian; Jia Shenli; Wang Lijun; Yuan Qingjun; Song Xiaochuan

    2008-01-01

    The motion of vacuum arc cathode spots has a very important influence on the efficiency of removing the oxide film on the metal surface. In this paper, the characteristics of cathode spot motion are investigated experimentally. Experiments were conducted in a detachable vacuum chamber with ac (50 Hz) arc current of 1 kA (rms). A stainless steel plate covered by an oxide layer was used as the cathode. The motion of cathode spots during the descaling process was photographed by a high-speed digital camera with an exposure time of 2 μs. Experimental results indicate that the motion of cathode spots is influenced by the interaction among individual cathode jets and the position of the anode as well as the surface condition. The waveform of arc voltage is also influenced by the motion of cathode spots

  5. Determination of the mechanism and extent of surface degradation in Ni-based cathode materials after repeated electrochemical cycling

    Directory of Open Access Journals (Sweden)

    Sooyeon Hwang

    2016-09-01

    Full Text Available We take advantage of scanning transmission electron microscopy and electron energy loss spectroscopy to investigate the changes in near-surface electronic structure and quantify the degree of local degradation of Ni-based cathode materials with the layered structure (LiNi0.8Mn0.1Co0.1O2 and LiNi0.4Mn0.3Co0.3O2 after 20 cycles of delithiation and lithiation. Reduction of transition metals occurs in the near-surface region of cathode materials: Mn is the major element to be reduced in the case of relatively Mn-rich composition, while reduction of Ni ions is dominant in Ni-rich materials. The valences of Ni and Mn ions are complementary, i.e., when one is reduced, the other is oxidized in order to maintain charge neutrality. The depth of degradation zone is found to be much deeper in Ni-rich materials. This comparative analysis provides important insights needed for the devising of new cathode materials with high capacity as well as long lifetime.

  6. Self-Driven Bioelectrochemical Mineralization of Azobenzene by Coupling Cathodic Reduction with Anodic Intermediate Oxidation

    International Nuclear Information System (INIS)

    Liu, Rong-Hua; Li, Wen-Wei; Sheng, Guo-Ping; Tong, Zhong-Hua; Lam, Michael Hon-Wah; Yu, Han-Qing

    2015-01-01

    Highlights: • Azobenzene was reduced to aniline at the cathode of an acetate-fueled MFC. • Aniline was degraded at the bioanode of a single-chamber MFC. • Cathodic reduction of azobenzene was coupled with anodic oxidation of aniline. • Self-driven, complete mineralization of azobenzene in an MFC was accomplished. - Abstract: Bioelectrochemical systems have been intensively studied as a promising technology for wastewater treatment and environment remediation. Coupling of the anodic and cathodic electrochemical reactions allows an enhanced degradation of recalcitrant organics, but external power supply is usually needed to overcome the thermodynamic barrier. In this work, we report a self-driven degradation of azobenzene in a microbial fuel cell (MFC), where the cathodic reduction of azobenzene was effectively coupled with the anodic oxidation of its reduction degradation intermediate (i.e., aniline). The anodic degradation rate of aniline, as the sole carbon source, was significantly higher than that under open-circuit conditions, suggesting a considerable bioelectrochemical oxidation of aniline. Output voltages up to 8 mV were obtained in the MFC. However, a shift of cathodic electron acceptor from oxygen to azobenzene resulted in a decreased aniline degradation rate and output voltage. The present work may provide valuable implications for development of sustainable bioelectrochemical technologies for environmental remediation

  7. Investigating the stability of cathode materials for rechargeable lithium ion batteries

    Science.gov (United States)

    Huang, Yiqing

    Lithium ion batteries are widely used in portable electronic devices and electric vehicles. However, safety is one of the most important issues for the Li-ion batteries' use. Some cathode materials, such as LiCoO 2, are thermally unstable in the charged state. Upon decomposition these cathode materials release O2, which could react with organic electrolyte, leading to a thermal runaway. Thus understanding the stability of the cathode materials is critical to the safety of lithium ion batteries. Olivine-type LiMnPO4 is a promising cathode material for lithium ion batteries because of its high energy density. We have revealed the critical role of carbon in the stability and thermal behaviour of olivine MnPO 4 obtained by chemical delithiation of LiMnPO4. (Li)MnPO 4 samples with various particle sizes and carbon contents were studied. Carbon-free LiMnPO4 obtained by solid state synthesis in O 2 becomes amorphous upon delithiation. Small amounts of carbon (0.3 wt.%) help to stabilize the olivine structure, so that completely delithiated crystalline olivine MnPO4 can be obtained. Larger amount of carbon (2 wt.%) prevents full delithiation. Heating in air, O2, or N 2 results in structural disorder (cathode materials and the electrolyte. The thermal stability of electrochemically delithiated Li0.1N 0.8C0.15Al0.05O2 (NCA), FePO4 (FP), Mn0.8Fe0.2PO4 (MFP), hydrothermally synthesized VOPO4, LiVOPO4 and electrochemically lithiated Li2VOPO4 is investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis, coupled with mass spectrometry (TGA-MS). The thermal stability is found in the order: NCA< VOPO4< MFP< FP=LiVOPO4=Li2VOPO4. Sealed capsule high pressure experiments show a phase transformation of VOPO4 → HVOPO4 → H2VOPO4 when VOPO4 reacts with electrolyte (1 M LiPF6 in EC: DMC=1:1) between 200 and 300 °C. Finally, we characterize the lithium storage and release mechanism of V2O5 aerogels by x-ray photoelectron spectroscopy (XPS). We study the

  8. LaNi1-xCoxO3-δ (x=0.4 to 0.7) cathodes for solid oxide fuel cells by infiltration

    DEFF Research Database (Denmark)

    Chrzan, Aleksander; Ovtar, Simona; Chen, Ming

    2015-01-01

    Performance of LaNi1-xCoxO3-δ (LNC) (x=0.4 to 0.7) as a cathode in solid oxide fuel cell (SOFC) is evaluated. Symmetrical cathode/electrolyte/cathode cells for electrochemical testing are prepared by infiltration of yttria stabilized zirconia (YSZ) backbone with LNC solutions. It is showed...... that the cathode infiltrated with LaNi0.5Co0.5O3-δ (LNC155) has the lowest polarization resistance and activation energy, 197 mΩ cm2 at 600 °C and 0.91 eV, respectively. Therefore it is the most promising material of the LNC group for electrochemical applications. X-ray diffraction analysis revealed that none...

  9. Fabrication and characterization of a cathode-supported tubular solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chunhua; Liu, Renzhu; Wang, Shaorong; Wang, Zhenrong; Qian, Jiqin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

    2009-07-15

    A cathode-supported tubular solid oxide fuel cell (CTSOFC) with the length of 6.0 cm and outside diameter of 1.0 cm has been successfully fabricated via dip-coating and co-sintering techniques. A crack-free electrolyte film with a thickness of {proportional_to}14 {mu}m was obtained by co-firing of cathode/cathode active layer/electrolyte/anode at 1250 C. The relative low densifying temperature for electrolyte was attributed to the large shrinkage of the green tubular which assisted the densification of electrolyte. The assembled cell was electrochemically characterized with humidified H{sub 2} as fuel and O{sub 2} as oxidant. The open circuit voltages (OCV) were 1.1, 1.08 and 1.06 V at 750, 800 and 850 C, respectively, with the maximum power densities of 157, 272 and 358 mW cm{sup -2} at corresponding temperatures. (author)

  10. A design strategy of large grain lithium-rich layered oxides for lithium-ion batteries cathode

    International Nuclear Information System (INIS)

    Jiang, Xiong; Wang, Zhenhua; Rooney, David; Zhang, Xiaoxue; Feng, Jie; Qiao, Jinshuo; Sun, Wang; Sun, Kening

    2015-01-01

    Highlights: • Ultrasound-assisted mixing lithium was used to synthesize Lithium-rich layered oxides. • Lithium-rich layered oxides composed of large grain had high capacity and high cycling stability. • This unique large grain overcomes stress-induced structural collapse caused by Li-ion insertion/extraction and reduces dissolution of Mn ions. • A new strategy of large grain could be employed to synthesize the other complex architectures for various applications. - Abstract: Li-rich materials are considered the most promising for Li-ion battery cathodes, as high capacity can be achieved. However, poor cycling stability is a critical drawback that leads to poor capacity retention. Here a strategy is used to synthesize a large-grain lithium-rich layered oxides to overcome this difficulty without sacrificing rate capability. This material is designed with micron scale grain with a width of about 300 nm and length of 1–3 μm. This unique structure has a better ability to overcome stress-induced structural collapse caused by Li-ion insertion/extraction and reduce the dissolution of Mn ions, which enable a reversible and stable capacity. As a result, this cathode material delivered a highest discharge capacity of around 308 mAh g −1 at a current density of 30 mA g −1 with retention of 88.3% (according to the highest discharge capacity) after 100 cycles, 190 mAh g −1 at a current density of 300 mA g −1 and almost no capacity fading after 100 cycles. Therefore, Lithium-rich material of large-grain structure is a promising cathode candidate in Lithium-ion batteries with high capacity and high cycle stability for application. This strategy of large grain may furthermore open the door to synthesize the other complex architectures for various applications

  11. Cathodic behaviour of nonstoichiometric (la,Sr){sub 1-x}(Co,Mn)O{sub 3} materials

    Energy Technology Data Exchange (ETDEWEB)

    Abrantes, J.C.C.; Rodrigues, C.M.S. [ESTG, Inst. Politecnico Viana do Castelo (Portugal); Labrincha, J.A.; Frade, J.R.; Marques, F.M.B. [Aveiro Univ. (Portugal). Dept. de Engenharia de Ceramica e do Vidro

    1996-10-01

    Solid oxide fuel cells (SOFCs) are expected to become competitive devices for electrical power generation, but successful application might be dependent on decreasing working temperatures to 800{sup o}C or lower, without detrimental effects on electrode processes and ohmic losses. This requires alternative electrode and electrolyte materials. The high electronic and oxygen ion conductivities of (La,Sr)CoO{sub 3} are promising for oxygen reduction, but high temperature reaction with yttria-stabilised zirconia (YSZ) electrolytes and excessive thermal expansion mismatch have prevented the current application of these cathode materials. Expected ways to try to minimise the reactivity of cobaltates involve A-site deficiency, and partial Mn for Co substitution. The latter is also expected to contribute to lower the thermal expansion mismatch. In this work (La,Sr){sub 1-x}(Co,Mn)O{sub 3} materials were prepared by solid state reaction and characterised by X-ray diffraction, thermal expansion and electrical conductivity measurements. The reactivity between these electrode materials and YSZ was also evaluated by XRD and SEM. Electrode layers were screen-printed on YSZ substrates and cathodic polarisation was measured at temperatures up to 1000{sup o}C. A-site substoichiometry and Co for Mn substitution affect the cathodic polarisation, but this also depends on some morphological features of screen-printed electrode layers. (author)

  12. Synthesis of a Flexible Freestanding Sulfur/Polyacrylonitrile/Graphene Oxide as the Cathode for Lithium/Sulfur Batteries

    Directory of Open Access Journals (Sweden)

    Huifen Peng

    2018-04-01

    Full Text Available Rechargeable lithium/sulfur (Li/S batteries have received quite significant attention over the years because of their high theoretical specific capacity (1672 mAh·g−1 and energy density (2600 mAh·g−1 which has led to more efforts for improvement in their electrochemical performance. Herein, the synthesis of a flexible freestanding sulfur/polyacrylonitrile/graphene oxide (S/PAN/GO as the cathode for Li/S batteries by simple method via vacuum filtration is reported. The S/PAN/GO hybrid binder-free electrode is considered as one of the most promising cathodes for Li/S batteries. Graphene oxide (GO slice structure provides effective ion conductivity channels and increases structural stability of the ternary system, resulting in excellent electrochemical properties of the freestanding S/PAN/GO cathode. Additionally, graphene oxide (GO membrane was able to minimize the polysulfides’ dissolution and their shuttle, which was attributed to the electrostatic interactions between the negatively-charged species and the oxygen functional groups on GO. Furthermore, these oxygen-containing functional groups including carboxyl, epoxide and hydroxyl groups provide active sites for coordination with inorganic materials (such as sulfur. It exhibits the initial reversible specific capacity of 1379 mAh·g−1 at a constant current rate of 0.2 C and maintains 1205 mAh·g−1 over 100 cycles (~87% retention. In addition, the freestanding S/PAN/GO cathode displays excellent coulombic efficiency (~100% and rate capability, delivering up to 685 mAh·g−1 capacity at 2 C.

  13. Effect of cathode gas humidification on performance and durability of Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Hagen, Anke; Liu, Yi-Lin

    2010-01-01

    The effect of cathode inlet gas humidification was studied on single anode supported Solid Oxide Fuel Cells (SOFC's). The studied cells were Risø 2 G and 2.5 G. The former consists of a LSM:YSZ composite cathode, while the latter consists of a LSCF:CGO composite cathode on a CGO protection layer....... The humidification effect was found to be dependent on both the degree of humidification and the cathode polarization. No significant effect of humidification was found at OCV which rules out the possibility of a traditional poisoning effect with a blocking of active sites. Post-mortem high resolution FEG......-SEM analysis showed clear changes at and around the cathode/electrolyte contact area. In contrast to Risø 2 G cells, a very high tolerance towards humidification of cathode gas air was observed for Risø 2.5 G cells with no detectable effect of humidification even when the humidification was as high as 12.8 mol%...

  14. Study of the Electrolytic Reduction of Uranium Oxide in LiCl-Li2O Molten Salts with an Integrated Cathode Assembly

    International Nuclear Information System (INIS)

    Park, Sung Bin; Seo, Chung Seok; Kang, Dae Seung; Kwon, Seon Gil; Park, Seong Won

    2005-01-01

    The electrolytic reduction of uranium oxide in a LiCl-Li 2 O molten salt system has been studied in a 10 g U 3 O 3 /batch-scale experimental apparatus with an integrated cathode assembly at 650 .deg. C. The integrated cathode assembly consists of an electric conductor, the uranium oxide to be reduced and the membrane for loading the uranium oxide. From the cyclic voltammograms for the LiCl-3 wt% Li 3 O system and the U 3 O 3 -LiCl-3 wt% Li 2 O system according to the materials of the membrane in the cathode assembly, the mechanisms of the predominant reduction reactions in the electrolytic reactor cell were to be understood; direct and indirect electrolytic reduction of uranium oxide. Direct and indirect electrolytic reductions have been performed with the integrated cathode assembly. Using the 325-mesh stainless steel screen the uranium oxide failed to be reduced to uranium metal by a direct and indirect electrolytic reduction because of a low current efficiency and with the porous magnesia membrane the uranium oxide was reduced successfully to uranium metal by an indirect electrolytic reduction because of a high current efficiency.

  15. Fabrication of polypyrrole/vanadium oxide nanotube composite with enhanced electrochemical performance as cathode in rechargeable batteries

    International Nuclear Information System (INIS)

    Zhou, Xiaowei; Chen, Xu; He, Taoling; Bi, Qinsong; Sun, Li; Liu, Zhu

    2017-01-01

    Highlights: • VO_xNTs were hydrothermally prepared using C_1_2H_2_7N as soft template with scalability. • Polypyrrole/VO_xNTs with less C_1_2H_2_7N template and higher conductivity were obtained. • Polypyrrole/VO_xNTs exhibit better performance as cathode for LIBs compared to VO_xNTs. • Further modification to VO_xNTs with desired electrochemical property can be expected. - Abstract: Vanadium oxide nanotubes (VO_xNTs) with hollow as well as multi-walled features were fabricated under hydrothermal condition by soft-template method. This novel VO_xNTs can be used as cathode material for lithium ion batteries (LIBs), but displaying low specific capacity and poor cycling performance owing to the residual of a mass of soft-template (C_1_2H_2_7N) and intrinsic low conductivity of VO_x. Cation exchange technique and oxidative polymerization process of pyrrole monomers were conducted to wipe off partial soft-template without electrochemical activity within VO_xNTs and simultaneously form polypyrrole coating on VO_xNTs, respectively. The resulting polypyrrole/VO_xNTs nanocomposite delivers much improved capacity and cyclic stability. Further optimizations, such as complete elimination of organic template and enhancing the crystallinity, can make this unique nanostructure a promising cathode for LIBs.

  16. Understanding the Role of Temperature and Cathode Composition on Interface and Bulk: Optimizing Aluminum Oxide Coatings for Li-Ion Cathodes

    International Nuclear Information System (INIS)

    Han, Binghong; Paulauskas, Tadas; Key, Baris; Peebles, Cameron; Park, Joong Sun

    2017-01-01

    Here, surface coating of cathode materials with Al_2O_3 has been shown to be a promising method for cathode stabilization and improved cycling performance at high operating voltages. However, a detailed understanding on how coating process and cathode composition changes the chemical composition, morphology and distribution of coating within cathode interface and bulk lattice, is still missing. In this study, we use a wet-chemical method to synthesize a series of Al_2O_3-coated LiNi_0_._5Co_0_._2Mn_0_._3O_2 and LiCoO_2 cathodes treated under various annealing temperatures and a combination of structural characterization techniques to understand the composition, homogeneity and morphology of coating layer and the bulk cathode. Nuclear magnetic resonance and electron microscopy results reveal that the nature of the interface is highly depended on the annealing temperature and cathode composition. For Al_2O_3-coated LiNi_0_._5Co_0_._2Mn_0_._3O_2, higher annealing temperature leads to more homogeneous and more closely attached coating on cathode materials, corresponding to better electrochemical performance. Lower Al_2O_3 coating content is found to be helpful to further improve the initial capacity and cyclability, which can greatly outperform the pristine cathode material. For Al_2O_3-coated LiCoO_2, the incorporation of Al into the cathode lattice is observed after annealing at high temperatures, implying the transformation from “surface coatings” to “dopants”, which is not observed for LiNi_0_._5Co_0_._2Mn_0_._3O_2. As a result, Al_2O_3-coated LiCoO_2 annealed at higher temperature shows similar initial capacity but lower retention compared to that annealed at a lower temperature, due to the intercalation of surface alumina into the bulk layered structure forming a solid solution.

  17. Understanding the Role of Temperature and Cathode Composition on Interface and Bulk: Optimizing Aluminum Oxide Coatings for Li-Ion Cathodes.

    Science.gov (United States)

    Han, Binghong; Paulauskas, Tadas; Key, Baris; Peebles, Cameron; Park, Joong Sun; Klie, Robert F; Vaughey, John T; Dogan, Fulya

    2017-05-03

    Surface coating of cathode materials with Al 2 O 3 has been shown to be a promising method for cathode stabilization and improved cycling performance at high operating voltages. However, a detailed understanding on how coating process and cathode composition change the chemical composition, morphology, and distribution of coating within the cathode interface and bulk lattice is still missing. In this study, we use a wet-chemical method to synthesize a series of Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 and LiCoO 2 cathodes treated under various annealing temperatures and a combination of structural characterization techniques to understand the composition, homogeneity, and morphology of the coating layer and the bulk cathode. Nuclear magnetic resonance and electron microscopy results reveal that the nature of the interface is highly dependent on the annealing temperature and cathode composition. For Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 , higher annealing temperature leads to more homogeneous and more closely attached coating on cathode materials, corresponding to better electrochemical performance. Lower Al 2 O 3 coating content is found to be helpful to further improve the initial capacity and cyclability, which can greatly outperform the pristine cathode material. For Al 2 O 3 -coated LiCoO 2 , the incorporation of Al into the cathode lattice is observed after annealing at high temperatures, implying the transformation from "surface coatings" to "dopants", which is not observed for LiNi 0.5 Co 0.2 Mn 0.3 O 2 . As a result, Al 2 O 3 -coated LiCoO 2 annealed at higher temperature shows similar initial capacity but lower retention compared to that annealed at a lower temperature, due to the intercalation of surface alumina into the bulk layered structure forming a solid solution.

  18. Polymer-Oxide Nanolayer/Al Composite Cathode for Efficient Polymer Light-Emitting Diodes

    National Research Council Canada - National Science Library

    Guo, Tzung-Fang; Wen, Ten-Chin

    2007-01-01

    ...). The author proposed to place a salt-free, polymer-oxide nanolayer at the interface between the light-emissive polymer layer with Al as the device cathode instead of using low work function metals, such as Ca or LiF/Al...

  19. Recycling of spent lithium-ion battery cathode materials by ammoniacal leaching

    Energy Technology Data Exchange (ETDEWEB)

    Ku, Heesuk; Jung, Yeojin; Jo, Minsang; Park, Sanghyuk [Department of Energy & Mineral Resources Engineering, Sejong University, Seoul 05006 (Korea, Republic of); Kim, Sookyung [Urban Mine Department, Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong-gu, Daejeon (Korea, Republic of); Yang, Donghyo, E-mail: ydh@kigam.re.kr [Urban Mine Department, Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong-gu, Daejeon (Korea, Republic of); Rhee, Kangin; An, Eung-Mo; Sohn, Jeongsoo [Urban Mine Department, Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong-gu, Daejeon (Korea, Republic of); Kwon, Kyungjung, E-mail: kfromberk@gmail.com [Department of Energy & Mineral Resources Engineering, Sejong University, Seoul 05006 (Korea, Republic of)

    2016-08-05

    Highlights: • Ammoniacal leaching is used to recover spent Li-ion battery cathode materials. • Leaching agents consist of ammonia, ammonium sulfite and ammonium carbonate. • Ammonium sulfite is a reductant and ammonium carbonate acts as pH buffer. • Co and Cu can be fully leached while Mn and Al are not leached. • Co recovery via ammoniacal leaching is economical compared to acid leaching. - Abstract: As the production and consumption of lithium ion batteries (LIBs) increase, the recycling of spent LIBs appears inevitable from an environmental, economic and health viewpoint. The leaching behavior of Ni, Mn, Co, Al and Cu from treated cathode active materials, which are separated from a commercial LIB pack in hybrid electric vehicles, is investigated with ammoniacal leaching agents based on ammonia, ammonium carbonate and ammonium sulfite. Ammonium sulfite as a reductant is necessary to enhance leaching kinetics particularly in the ammoniacal leaching of Ni and Co. Ammonium carbonate can act as a pH buffer so that the pH of leaching solution changes little during leaching. Co and Cu can be fully leached out whereas Mn and Al are hardly leached and Ni shows a moderate leaching efficiency. It is confirmed that the cathode active materials are a composite of LiMn{sub 2}O{sub 4}, LiCo{sub x}Mn{sub y}Ni{sub z}O{sub 2,} Al{sub 2}O{sub 3} and C while the leach residue is composed of LiNi{sub x}Mn{sub y}Co{sub z}O{sub 2}, LiMn{sub 2}O{sub 4}, Al{sub 2}O{sub 3}, MnCO{sub 3} and Mn oxides. Co recovery via the ammoniacal leaching is believed to gain a competitive edge on convenitonal acid leaching both by reducing the sodium hydroxide expense for increasing the pH of leaching solution and by removing the separation steps of Mn and Al.

  20. Exfoliation and reassembly of cobalt oxide nanosheets into a reversible lithium-ion battery cathode.

    Science.gov (United States)

    Compton, Owen C; Abouimrane, Ali; An, Zhi; Palmeri, Marc J; Brinson, L Catherine; Amine, Khalil; Nguyen, SonBinh T

    2012-04-10

    An exfoliation-reassembly-activation (ERA) approach to lithium-ion battery cathode fabrication is introduced, demonstrating that inactive HCoO(2) powder can be converted into a reversible Li(1-x) H(x) CoO(2) thin-film cathode. This strategy circumvents the inherent difficulties often associated with the powder processing of the layered solids typically employed as cathode materials. The delamination of HCoO(2) via a combination of chemical and mechanical exfoliation generates a highly processable aqueous dispersion of [CoO(2) ](-) nanosheets that is critical to the ERA approach. Following vacuum-assisted self-assembly to yield a thin-film cathode and ion exchange to activate this material, the generated cathodes exhibit excellent cyclability and discharge capacities approaching that of low-temperature-prepared LiCoO(2) (~83 mAh g(-1) ), with this good electrochemical performance attributable to the high degree of order in the reassembled cathode. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Improved electrochemical performance of LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} cathode material by double-layer coating with graphene oxide and V{sub 2}O{sub 5} for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Wenbin, E-mail: wenbin.luo@hotmail.com; Zheng, Baolin

    2017-05-15

    Highlights: • Citric acid assisted sol-gel method was used for synthesizing LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2}. • The pristine LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} was surface-modified by double-layer coating. • The double coating layer consists of graphene oxide and V{sub 2}O{sub 5}. • Electrochemical performance was improved by double-layer coating. - Abstract: LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} cathode material synthesized by a sol-gel method was surface-modified by double-layer coating. The results of X-ray diffraction (XRD) confirm that the intrinsic structure was no change after surface modification. A double-layer structure consisting of an inner V{sub 2}O{sub 5} (VO) layer and an outer conductive graphene oxide (GO) layer was coated on the surface of active material, as confirmed by transmission electron microscopy (TEM). The results of field emission scanning electron microscope (FE-SEM) equipped with an energy dispersive spectroscope (EDS) show that both graphene oxide and V{sub 2}O{sub 5} uniformly covered LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} cathode material. The double-layer-coated LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} cathode material shows improved electrochemical performance with a capacity retention of 74.2% after 50 cycles in a range of 2.5–4.5 V at 55 °C, compared with only 67.8% capacity retention for the pristine material. In addition, the double-layer-coated LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} releases 116.6 mAh g{sup −1} under a high current rate, while the pristine material only remains at 105.7 mAh g{sup −1}. The results can be ascribed to the double coating layer not only avoids the side reaction between electrolyte and active material but also promotes Li{sup +} and electronic conductivity. Differential capacity (dQ/dV) and electrochemical impedance spectroscopy (EIS) measurements reveal that the double coating layer effectively suppresses the increase of the electrode

  2. Characterization of cathode materials SrCoO3 and La0,2Sr0,8CoO3 for use in solid oxide fuel cells (SOFC); Caracterizacao de materiais catodicos SrCoO3 e La0,2Sr0,8CoO3 para aplicacao em celulas a combustivel de oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Galvao, G.O.; Aquino, F.M; Silva, R.M.; Medeiros, I.D.M. de, E-mail: gabriela.galvao@cear.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

    2016-07-01

    Mixed oxide ceramics with chemical structure of ABO{sub 3} type are promising candidates for cathodes of solid oxide fuel cells (SOFC) for performing well on the electrical conductivity and thermal stability. Various methods of preparation have been studied and used for the synthesis of these materials. In this study, SrCoO{sub 3} and La{sub 0,2}Sr{sub 0,8}CoO{sub 3} perovskites were synthesized using gelatin as directing agent with the purpose of producing homogeneous and porous particles. The powders obtained at 350 ° C / 2 h were calcined at 600, 800 and 1000 ° C for 4 hours and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that gelatin is a good polymerizing agent for metal ions as the material showed characteristic peaks of perovskite, with good porosity and uniformity. Furthermore, the method of synthesis employed has advantages related to cost and toxicity, which are very low. (author)

  3. Atomic-scale understanding of non-stoichiometry effects on the electrochemical performance of Ni-rich cathode materials

    Science.gov (United States)

    Kong, Fantai; Liang, Chaoping; Longo, Roberto C.; Zheng, Yongping; Cho, Kyeongjae

    2018-02-01

    As the next-generation high energy capacity cathode materials for Li-ion batteries, Ni-rich oxides face the problem of obtaining near-stoichiometric phases due to excessive Ni occupying Li sites. These extra-Ni-defects drastically affect the electrochemical performance. Despite of its importance, the fundamental correlation between such defects and the key electrochemical properties is still poorly understood. In this work, using density-functional-theory, we report a comprehensive study on the effects of non-stoichiometric phases on properties of Ni-rich layered oxides. For instance, extra-Ni-defects trigger charge disproportionation reaction within the system, alleviating the Jahn-Teller distortion of Ni3+ ions, which constitutes an important reason for their low formation energies. Kinetic studies of these defects reveal their immobile nature, creating a "pillar effect" that increases the structural stability. Ab initio molecular dynamics revealed Li depletion regions surrounding extra-Ni-defects, which are ultimate responsible for the arduous Li diffusion and re-intercalation, resulting in poor rate performance and initial capacity loss. Finally, the method with combination of high valence cation doping and ion-exchange synthesis is regarded as the most promising way to obtain stoichiometric oxides. Overall, this work not only deepens our understanding of non-stoichiometric Ni-rich layered oxides, but also enables further optimizations of high energy density cathode materials.

  4. Metal-oxide-junction, triple point cathodes in a relativistic magnetron

    International Nuclear Information System (INIS)

    Jordan, N. M.; Gilgenbach, R. M.; Hoff, B. W.; Lau, Y. Y.

    2008-01-01

    Triple point, defined as the junction of metal, dielectric, and vacuum, is the location where electron emission is favored in the presence of a sufficiently strong electric field. To exploit triple point emission, metal-oxide-junction (MOJ) cathodes consisting of dielectric ''islands'' over stainless steel substrates have been fabricated. The two dielectrics used are hafnium oxide (HfO x ) for its high dielectric constant and magnesium oxide (MgO) for its high secondary electron emission coefficient. The coatings are deposited by ablation-plasma-ion lithography using a KrF laser (0-600 mJ at 248 nm) and fluence ranging from 3 to 40 J/cm 2 . Composition and morphology of deposited films are analyzed by scanning electron microscopy coupled with x-ray energy dispersive spectroscopy, as well as x-ray diffraction. Cathodes are tested on the Michigan Electron Long-Beam Accelerator with a relativistic magnetron, at parameters V=-300 kV, I=1-15 kA, and pulse lengths of 0.3-0.5 μs. Six variations of the MOJ cathode are tested, and are compared against five baseline cases. It is found that particulate formed during the ablation process improves the electron emission properties of the cathodes by forming additional triple points. Due to extensive electron back bombardment during magnetron operation, secondary electron emission also may play a significant role. Cathodes exhibit increases in current densities of up to 80 A/cm 2 , and up to 15% improvement in current start up time, as compared to polished stainless steel cathodes

  5. Antimony doped barium strontium ferrite perovskites as novel cathodes for intermediate-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Yihan, E-mail: lyhyy@mail.ustc.edu.cn [School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116 (China); Lu, Xiaoyong [China Anhui Key Laboratory of Low Temperature Co-fired Materials, Department of Chemistry, Huainan Normal University, Huainan, Anhui, 232001 (China); Niu, Jinan; Chen, Hui [School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116 (China); Ding, Yanzhi [China Anhui Key Laboratory of Low Temperature Co-fired Materials, Department of Chemistry, Huainan Normal University, Huainan, Anhui, 232001 (China); Ou, Xuemei [School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116 (China); Zhao, Ling [Department of Material Science and Chemistry, China University of Geosciences, Wuhan, 430074 (China)

    2016-05-05

    Antimony was doped to barium strontium ferrite to produce ferrite-based perovskites with a composition of Ba{sub 0.5}Sr{sub 0.5}Fe{sub 1−x}Sb{sub x}O{sub 3−δ} (x = 0.0, 0.05, 0.1) as novel cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The perovskite properties including oxygen nonstoichiometry (δ), mean valence of B-site, tolerance factors, thermal expansion coefficient (TEC) and electrical conductivity (σ) are explored as a function of antimony content. By defect chemistry analysis, the TECs decrease since the variable oxygen vacancy concentration is decreased by Sb doping, and σ decreases with x due to the reduced charge concentration of Fe{sup 4+} content. Consequently, the electrochemical performance was substantially improved and the interfacial polarization resistance was reduced from 0.213 to 0.120 Ωcm{sup 2} at 700 °C with Sb doping. The perovskite with x = 1.0 is suggested as the most promising composition as SOFC cathode material. - Highlights: • Antimony is doped to barium strontium ferrite to produce novel cathodes. • δ, TECs and σ are evaluated as a function of antimony content. • The electrochemical performance is substantially improved with antimony doping.

  6. Praseodymium Cuprate Thin Film Cathodes for Intermediate Temperature Solid Oxide Fuel Cells: Roles of Doping, Orientation, and Crystal Structure.

    Science.gov (United States)

    Mukherjee, Kunal; Hayamizu, Yoshiaki; Kim, Chang Sub; Kolchina, Liudmila M; Mazo, Galina N; Istomin, Sergey Ya; Bishop, Sean R; Tuller, Harry L

    2016-12-21

    Highly textured thin films of undoped, Ce-doped, and Sr-doped Pr 2 CuO 4 were synthesized on single crystal YSZ substrates using pulsed laser deposition to investigate their area-specific resistance (ASR) as cathodes in solid-oxide fuel cells (SOFCs). The effects of T' and T* crystal structures, donor and acceptor doping, and a-axis and c-axis orientation on ASR were systematically studied using electrochemical impedance spectroscopy on half cells. The addition of both Ce and Sr dopants resulted in improvements in ASR in c-axis oriented films, as did the T* crystal structure with the a-axis orientation. Pr 1.6 Sr 0.4 CuO 4 is identified as a potential cathode material with nearly an order of magnitude faster oxygen reduction reaction kinetics at 600 °C compared to thin films of the commonly studied cathode material La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3-δ . Orientation control of the cuprate films on YSZ was achieved using seed layers, and the anisotropy in the ASR was found to be less than an order of magnitude. The rare-earth doped cuprate was found to be a versatile system for study of relationships between bulk properties and the oxygen reduction reaction, critical for improving SOFC performance.

  7. Real-time thermal imaging of solid oxide fuel cell cathode activity in working condition

    DEFF Research Database (Denmark)

    Montanini, Roberto; Quattrocchi, Antonino; Piccolo, Sebastiano

    2016-01-01

    Electrochemical methods such as voltammetry and electrochemical impedance spectroscopy are effective for quantifying solid oxide fuel cell (SOFC) operational performance, but not for identifying and monitoring the chemical processes that occur on the electrodes’ surface, which are thought...... to be strictly related to the SOFCs’ efficiency. Because of their high operating temperature, mechanical failure or cathode delamination is a common shortcoming of SOFCs that severely affects their reliability. Infrared thermography may provide a powerful tool for probing in situ SOFC electrode processes...... in detecting the onset of cell failure during normal operation and in monitoring cathode activity when the cell is fed with different types of fuels....

  8. Effect of Metal (Mn, Ti Doping on NCA Cathode Materials for Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Dao Yong Wan

    2018-01-01

    Full Text Available NCA (LiNi0.85Co0.10Al0.05-x MxO2, M=Mn or Ti, x < 0.01 cathode materials are prepared by a hydrothermal reaction at 170°C and doped with Mn and Ti to improve their electrochemical properties. The crystalline phases and morphologies of various NCA cathode materials are characterized by XRD, FE-SEM, and particle size distribution analysis. The CV, EIS, and galvanostatic charge/discharge test are employed to determine the electrochemical properties of the cathode materials. Mn and Ti doping resulted in cell volume expansion. This larger volume also improved the electrochemical properties of the cathode materials because Mn4+ and Ti4+ were introduced into the octahedral lattice space occupied by the Li-ions to expand the Li layer spacing and, thereby, improved the lithium diffusion kinetics. As a result, the NCA-Ti electrode exhibited superior performance with a high discharge capacity of 179.6 mAh g−1 after the first cycle, almost 23 mAh g−1 higher than that obtained with the undoped NCA electrode, and 166.7 mAh g−1 after 30 cycles. A good coulombic efficiency of 88.6% for the NCA-Ti electrode is observed based on calculations in the first charge and discharge capacities. In addition, the NCA-Ti cathode material exhibited the best cycling stability of 93% up to 30 cycles.

  9. Silicon oxide based high capacity anode materials for lithium ion batteries

    Science.gov (United States)

    Deng, Haixia; Han, Yongbong; Masarapu, Charan; Anguchamy, Yogesh Kumar; Lopez, Herman A.; Kumar, Sujeet

    2017-03-21

    Silicon oxide based materials, including composites with various electrical conductive compositions, are formulated into desirable anodes. The anodes can be effectively combined into lithium ion batteries with high capacity cathode materials. In some formulations, supplemental lithium can be used to stabilize cycling as well as to reduce effects of first cycle irreversible capacity loss. Batteries are described with surprisingly good cycling properties with good specific capacities with respect to both cathode active weights and anode active weights.

  10. Rare earth metal oxides as BH4-tolerance cathode electrocatalysts for direct borohydride fuel cells

    Institute of Scientific and Technical Information of China (English)

    NI Xuemin; WANG Yadong; GUO Feng; YAO Pei; PAN Mu

    2012-01-01

    Rare earth metal oxides (REMO) as cathode electrocatalysts in direct borohydride fuel cell (DBFC) were investigated.The REMO electrocatalysts tested showed favorable activity to the oxygen electro-reduction reaction and strong tolerance to the attack of BH4- in alkaline electrolytes.The simple membraneless DBFCs using REMO as cathode electrocatalyst and using hydrogen storage alloy as anodic electrocatalyst exhibited an open circuit of about 1 V and peak power of above 60 mW/cm2.The DBFC using Sm2O3 as cathode electrocatalyst showed a relatively better performance.The maximal power density of 76.2 mW/cm2 was obtained at the cell voltage of 0.52 V.

  11. Separation factor dependence upon cathode material for tritium separation from heavy water by electrolysis

    International Nuclear Information System (INIS)

    Ogata, Y.; Sakuma, Y.; Ohtani, N.; Kotaka, M.

    2002-01-01

    Using three cathode materials, i.e. carbon (C), stainless steel (SUS), and nickel (Ni), tritium was separated from heavy water by electrolysis, and the separation factors were compared. To separate hydrogen isotopes, heavy water was electrolyzed by an electrolysis device with a solid polymer electrode (SPE), which needed no electrolyte additives for electrolysis. The anode was made of 3 mm thickness of a sintered porous titanium plate covered with iridium oxide. The cathode was made of the same thickness of a sintered porous carbon, stainless steel, or nickel plate. Heavy water or light water spiked with tritiated water was electrolyzed 20 A x 60 min with the electrolysis cell temperature at 10, 20 or 30degC, and 15 A x 80 min at 5degC. The produced hydrogen and oxygen gases were recombined using a palladium catalyst with nitrogen gas as a carrier. The activities of the water in the electrolysis cell and of the recombined water were analyzed using a liquid scintillation counter. The apparent D-T separation factor (SF D/T ) and H-T separation factor (SF H/T ) were calculated as quotient the specific activity of the water in the cell divided by that of the recombined water. The electrolysis potential to keep the current 20 A was 2-3 V. The average yields of the recombined water were 95%. At the cell temperature of 20degC, SF D/T (C), SF D/T (SUS), and SF D/T (Ni) were 2.42, 2.17, and 2.05, respectively. At the same temperature, SF H/T (C), SF H/T (SUS), and SF H/T (Ni) were 12.5, 10.8, and 11.8, respectively. The SFs were in agreement with the results in other works. The SFs were changed with the cell temperature. (author)

  12. High-Capacity Micrometer-Sized Li 2 S Particles as Cathode Materials for Advanced Rechargeable Lithium-Ion Batteries

    KAUST Repository

    Yang, Yuan

    2012-09-19

    Li 2S is a high-capacity cathode material for lithium metal-free rechargeable batteries. It has a theoretical capacity of 1166 mAh/g, which is nearly 1 order of magnitude higher than traditional metal oxides/phosphates cathodes. However, Li 2S is usually considered to be electrochemically inactive due to its high electronic resistivity and low lithium-ion diffusivity. In this paper, we discover that a large potential barrier (∼1 V) exists at the beginning of charging for Li 2S. By applying a higher voltage cutoff, this barrier can be overcome and Li 2S becomes active. Moreover, this barrier does not appear again in the following cycling. Subsequent cycling shows that the material behaves similar to common sulfur cathodes with high energy efficiency. The initial discharge capacity is greater than 800 mAh/g for even 10 μm Li 2S particles. Moreover, after 10 cycles, the capacity is stabilized around 500-550 mAh/g with a capacity decay rate of only ∼0.25% per cycle. The origin of the initial barrier is found to be the phase nucleation of polysulfides, but the amplitude of barrier is mainly due to two factors: (a) charge transfer directly between Li 2S and electrolyte without polysulfide and (b) lithium-ion diffusion in Li 2S. These results demonstrate a simple and scalable approach to utilizing Li 2S as the cathode material for rechargeable lithium-ion batteries with high specific energy. © 2012 American Chemical Society.

  13. First Principles Studies of Perovskites for Intermediate Temperature Solid Oxide Fuel Cell Cathodes

    KAUST Repository

    Salawu, Omotayo Akande

    2017-05-15

    Fundamental advances in cathode materials are key to lowering the operating temperature of solid oxide fuel cells (SOFCs). Detailed understanding of the structural, electronic and defect formation characteristics are essential for rational design of cathode materials. In this thesis we employ first principles methods to study La(Mn/Co)O3 and LnBaCo2O5+δ (Ln = Pr, Gd; δ = 0.5, 1) as cathode for SOFCs. Specifically, factors affecting the O vacancy formation and migration are investigated. We demonstrate that for LaMnO3 the anisotropy effects often neglected at high operating temperatures become relevant when the temperature is lowered. We show that this fact has consequences for the material properties and can be further enhanced by strain and Sr doping. Tensile strain promotes both the O vacancy formation and migration in pristine and Sr doped LaMnO3, while Sr doping enhances the O vacancy formation but not the migration. The effect of A-site hole doping (Mg2+, Ca2+ or Ba2+) on the electronic and magnetic properties as well as the O vacancy formation and migration in LaCoO3 are studied. All three dopants are found to facilitate O vacancy formation. Substitution of La3+ with Ba2+/Mg2+ yields the lowest O vacancy formation energy for low/intermediate spin Co, implying that not only the structure, but also the spin state of Co is a key parameter. Only for low spin Co the ionic radius is correlated with the O migration barrier. Enhanced migration for intermediate spin Co is ascribed to the availability of additional space at the transition state. For LnBaCo2O5+δ we compare the O vacancy formation in GdBaCo2O5.5 (Pmmm symmetry) and GdBaCo2O6 (P4/mmm symmetry), and the influence of Sr doping. The O vacancy formation energy is demonstrated to be smaller in the already O deficient compound. This relation is maintained under Sr doping. It turns out that Sr doping can be utilized to significantly enhance the O vacancy formation in both compounds. The observed trends are

  14. LaNi0.6Co0 4O3-δ dip-coated on Fe-Cr mesh as a composite cathode contact material on intermediate solid oxide fuel cells

    Science.gov (United States)

    Morán-Ruiz, Aroa; Vidal, Karmele; Larrañaga, Aitor; Laguna-Bercero, Miguel Angel; Porras-Vázquez, Jose Manuel; Slater, Peter Raymond; Arriortua, María Isabel

    2014-12-01

    The feasibility of using Crofer22APU mesh dip coated with LaNi0.6Co0.4O3-δ (LNC) ceramic paste as a uniform contact layer on a Crofer22APU channeled interconnect was studied. The control of LNC dip coating thickness on Fe-Cr mesh was carried out by rheological measurements of the suspension. SEM cross-section of formed composite contact material showed good adherence between ceramic and metallic components. The measured area specific resistance (ASR) value at 800 °C was 0.46 ± 0.01 mΩ cm2, indicating low contact resistance itself. The long term stability of metallic/ceramic composite was also studied. The contact resistance, when composite contact material was adhered to channeled Crofer22APU interconnect, was 5.40 ± 0.01 mΩ cm2, which is a suitable value for the performance of IT-SOFC stack. The stability of the system after treating at 800 °C for 1000 h was characterized using X-ray Micro-Diffraction (XRMD), Scanning Electron Microscope equipped with an Energy Dispersive X-ray analyzer (SEM-EDX) and X-ray Photoelectron Spectroscopy (XPS) techniques. The oxidation rate of the alloy and Fe3O4 phase formation were enhanced on the channels of the interconnect. Thus, the formation of CrO3 (g) and CrO2(OH)2 (g) species was accelerated on the composite surface under the channel. Through XRMD and XPS analysis the coexistence of two perovskite phases (initial LNC and Cr-perovskite) was observed.

  15. Cathode material for lithium ion accumulators prepared by screen printing for Smart Textile applications

    Science.gov (United States)

    Syrový, T.; Kazda, T.; Syrová, L.; Vondrák, J.; Kubáč, L.; Sedlaříková, M.

    2016-03-01

    The presented study is focused on the development of LiFePO4 based cathode for thin and flexible screen printed secondary lithium based accumulators. An ink formulation was developed for the screen printing technique, which enabled mass production of accumulator's cathode for Smart Label and Smart Textile applications. The screen printed cathode was compared with an electrode prepared by the bar coating technique using an ink formulation based on the standard approach of ink composition. Obtained LiFePO4 cathode layers were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and galvanostatic charge/discharge measurements at different loads. The discharge capacity, capacity retention and stability at a high C rate of the LiFePO4 cathode were improved when Super P and PVDF were replaced by conductive polymers PEDOT:PSS. The achieved capacity during cycling at various C rates was approximately the same at the beginning and at the end, and it was about 151 mAh/g for cycling under 1C. The obtained results of this novelty electrode layer exceed the parameters of several electrode layers based on LiFePO4 published in literature in terms of capacity, cycling stability and overcomes them in terms of simplicity/industrial process ability of cathode layer fabrication and electrode material preparation.

  16. Enhanced electrochemical performance of the solid oxide fuel cell cathode using Ca3Co4O9+δ

    DEFF Research Database (Denmark)

    Samson, Alfred Junio; Søgaard, Martin; Van Nong, Ngo

    2011-01-01

    This paper reports on the electrochemical performance of an SOFC cathode for potential use in intermediate-temperature solid oxide fuel cells (IT-SOFCs) using the oxygen non-stoichiometric misfit-layered cobaltite Ca3Co4O9+δ or composites of Ca3Co4O9+δ with Ce0.9Gd0.1O1.95 (CGO/Ca3Co4O9+δ......). Electrochemical impedance spectroscopy revealed that symmetric cells with an electrode of pure Ca3Co4O9+δ exhibit a cathode polarization resistance (Rp) of 12.4 Ω cm2, at 600 °C in air. Strikingly, Rp of the composite CGO/Ca3Co4O9+δ with 50 vol.% CGO was reduced by a factor of 19 (i.e. Rp = 0.64 Ω cm2......), the lowest value reported so far for the Ca3Co4O9 family of compounds. These findings together with the reported thermal expansion coefficient, good compatibility with CGO and chemical durability of this material suggest that it is a promising candidate cathode for IT-SOFCs....

  17. Unraveling the Role of Transport, Electrocatalysis, and Surface Science in the Solid Oxide Fuel Cell Cathode Oxygen Reduction Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Gopalan, Srikanth [Boston Univ., MA (United States)

    2017-04-06

    This final report for project FE0009656 covers the period from 10/01/2012 to 09/30/2015 and covers research accomplishments on the effects of carbon dioxide on the surface composition and structure of cathode materials for solid oxide fuel cells (SOFCs), specifically La1-xSrxFeyCo1- yO3-δ (LSCF). Epitaxially deposited thin films of LSCF on various single-crystal substrates have revealed the selective segregation of strontium to the surface thereby resulting in a surface enrichment of strontium. The near surface compositional profile in the films have been measured using total x-ray fluorescence (TXRF), and show that the kinetics of strontium segregation are higher at higher partial pressures of carbon dioxide. Once the strontium segregates to the surface, it leads to the formation of precipitates of SrO which convert to SrCO3 in the presence of even modest concentrations of carbon dioxide in the atmosphere. This has important implications for the performance of SOFCs which is discussed in this report. These experimental observations have also been verified by Density Functional Theory calculations (DFT) which predict the conditions under which SrO and SrCO3 can occur in LSCF. Furthermore, a few cathode compositions which have received attention in the literature as alternatives to LSCF cathodes have been studied in this work and shown to be thermodynamically unstable under the operating conditions of the SOFCs.

  18. The application and study of an oxide-impregnated nickel-matrix cathode for Beijing proton linac

    International Nuclear Information System (INIS)

    Xia Dehong; Shi Rongjian

    1996-01-01

    A low power consumption oxide-impregnated nickel-matrix cathode used in the Duoplasmatron ion source of the Beijing Proton Linac (BPL) is presented. Its structure, treatment process of nickel-foam rubber on metal matrix surface and manufacture of dip coating carbonate are briefly introduced. The activation method and experiment results of the cathode are described. The principal factors which influence the cathode lifetime are discussed. The lifetime of the cathode is up to 2110 h while the extracted pulsed beam current is about 200 mA

  19. Influence of cathode on the electro-generation of peroxydisulfuric acid oxidant and its application for effective removal of SO_2 by room temperature electro-scrubbing process

    International Nuclear Information System (INIS)

    Balaji, Subramanian; Muthuraman, Govindan; Moon, Il Shik

    2015-01-01

    Highlights: • Electrolytic production of peroxydisulfuric acid (PDSA) with BDD anode. • PDSA yield enhanced by proper selection of cathode material. • Electro-scrubbing of SO_2 in presence of PDSA monitored by online FTIR analyzer. • 100% SO_2 removal was achieved for 25 ppm and 50 ppm in less than 10 min. - Abstract: Peroxydisulfuric acid oxidant (H_2S_2O_8) was electro-generated using boron doped diamond (BDD) anode in an undivided electrolytic cell under the optimized conditions and used for the oxidative removal of gaseous SO_2. The influence of the nature of cathode material on the formation yield of H_2S_2O_8 was investigated with Ti, Pt, Zr and DSA electrodes in a flow type electrolytic cell under batch recirculation mode. Among the various cathodes employed Ti exhibited a good performance and the formation yield was nearly doubled (0.19 M) compared to the reported value of 0.07 M. The optimization of electrode area ratio between the anode and cathode brought out the fact that for nearly 8 times smaller Ti cathode (8.75:1) the achieved yield was ∼65% higher than the 1:1 ratio of anode and cathode. The highest concentration of 6.8% (0.48 M) H_2S_2O_8 was seen for 35 cm"2 BDD anode with 4 cm"2 Ti at 20 °C with the measured redox potential value of +1200 mV. The oxidative removal of SO_2 in an electro-scrubbing column attached to the online production of peroxydisulfuric acid under the optimized conditions of cell parameters shows that SO_2 removal efficiency was nearly 100% for 25 and 50 ppm inlet concentrations and 96% for 100 ppm at the room temperature of 25 °C.

  20. Development of Graphene-based novel cathode material in MES system

    DEFF Research Database (Denmark)

    Chen, Leifeng; Aryal, Nabin; Ammam, Fariza

    2014-01-01

    Sporomusa ovata (S.O) typically have a negative outer-surface charge. The graphene oxide (GO) is the acceptor of the electron. If the GO accept electrons from the Sporomusa ovata and the GO can be reduced to graphene. This will lead to in situ construction of a bacteria/graphene network in the cathode......It has been reported that physical contact between unique nanostructures of electrode and bacteria isimportant for microbial electrosynthesis. The higher specific surface area of cathode can increase contact interface area with bacteria and enhance electron-exchange at the electrode surface...... and RamanSpectrum to character the GO and R-GO. The density of the Sporomusa ovate on the R-GO cathode can becharactered by the confocal laser-scanning fuorescence microscopyer. Acetate is measured via high performance liquid chromatography (HPLC). The images of R-GO/Sporomusa ovate can be characterizedand...

  1. Advanced manganese oxide material for rechargeable lithium cells

    Energy Technology Data Exchange (ETDEWEB)

    Atwater, Terrill B.; Salkind, Alvin J. [Rutgers University, Piscataway, NJ (United States)

    2006-11-22

    A family of potassium-doped manganese oxide materials were synthesized with the stoichiometric formula Li{sub 0.9-X}K{sub X}Mn{sub 2}O{sub 4}, where X=0.0-0.25 and evaluated for their viability as a cathode material for a rechargeable lithium battery. A performance maximum was found at X=0.1 where the initial specific capacity for the lithium-potassium-doped manganese dioxide electrochemical couple was 130mAhg{sup -1} of active cathode material. The discharge capacity of the system was maintained through 90 cycles (95% initial capacity). Additionally, the capacity was maintained at greater than 90% initial discharge through 200 cycles. Other variants demonstrated greater than 75% initial discharge through 200 cycles at comparable capacity. (author)

  2. Li-rich layer-structured cathode materials for high energy Li-ion batteries

    Science.gov (United States)

    Li, Liu; Lee, Kim Seng; Lu, Li

    2014-08-01

    Li-rich layer-structured xLi2MnO3 ṡ (1 - x)LiMO2 (M = Mn, Ni, Co, etc.) materials have attracted much attention due to their extraordinarily high reversible capacity as the cathode material in Li-ion batteries. To better understand the nature of this type of materials, this paper reviews history of development of the Li-rich cathode materials, and provides in-depth study on complicated crystal structures and reaction mechanisms during electrochemical charge/discharge cycling. Despite the fabulous capability at low rate, several drawbacks still gap this type of high-capacity cathode materials from practical applications, for instance the large irreversible capacity loss at first cycle, poor rate capability, severe voltage decay and capacity fade during electrochemical charge/discharge cycling. This review will also address mechanisms for these inferior properties and propose various possible solutions to solve above issues for future utilization of these cathode materials in commercial Li-ion batteries.

  3. Mathematical modeling of current density distribution in composite cathode of solid oxide fuel cells. Paper no. IGEC-1-099

    International Nuclear Information System (INIS)

    Kenney, B.; Karan, K.

    2005-01-01

    Cathodes processes in a solid oxide fuel cell (SOFC) are thought to dominate the overall electrochemical losses. One strategy for minimizing the cathode electrochemical losses in a state-of-the-art SOFC that utilize lanthanum-strontium-manganate (LSM) electrocatalyst and yttria-stabilized-zirconia (YSZ) electrolyte is to utilize composite cathodes comprising a mixture of LSM and YSZ. Composite cathodes improve performance by extending the active reaction zone from electrolyte-electrode interface to throughout the electrode. In this study, a two-dimensional composite cathode model was developed to assess cathode performance in terms of current density distributions. The model results indicate that geometric and microstructural parameters strongly influence current density distribution. In addition electrode composition affects magnitude and distribution of current. An optimum composition for equal-sized LSM/YSZ is 40 vol% LSM and 60 vol% YSZ at 900 o C. (author)

  4. Testing of a cathode fabricated by painting with a brush pen for anode-supported tubular solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Renzhu; Zhao, Chunhua; Li, Junliang; Wang, Shaorong; Wen, Zhaoyin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

    2010-01-15

    We have studied the properties of a cathode fabricated by painting with a brush pen for use with anode-supported tubular solid oxide fuel cells (SOFCs). The porous cathode connects well with the electrolyte. A preliminary examination of a single tubular cell, consisting of a Ni-YSZ anode support tube, a Ni-ScSZ anode functional layer, a ScSZ electrolyte film, and a LSM-ScSZ cathode fabricated by painting with a brush pen, has been carried out, and an improved performance is obtained. The ohmic resistance of the cathode side clearly decreases, falling to a value only 37% of that of the comparable cathode made by dip-coating at 850 C. The single cell with the painted cathode generates a maximum power density of 405 mW cm{sup -2} at 850 C, when operating with humidified hydrogen. (author)

  5. Microwave synthesis of copper network onto lithium iron phosphate cathode materials for improved electrochemical performance

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Chien-Te, E-mail: cthsieh@saturn.yzu.edu.tw [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320, Taiwan (China); Liu, Juan-Ru [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320, Taiwan (China); Juang, Ruey-Shin [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan 333, Taiwan (China); Lee, Cheng-En; Chen, Yu-Fu [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320, Taiwan (China)

    2015-03-01

    Herein reported is an efficient microwave-assisted (MA) approach for growing Cu network onto LiFePO{sub 4} (LFP) powders as cathode materials for high-performance Li-ion batteries. The MA approach is capable of depositing highly-porous Cu network, fully covered the LFP powders. The electrochemical performance of Cu-coated LFP cathodes are well characterized by charge/discharge cycling and electrochemical impedance spectroscopy (EIS). The Cu network acts as the key role in improving the specific capacity, rate capability, electrode polarization, as compared to fresh LFP cathode without the Cu coating. The EIS incorporated with equivalent circuit reveals that the completed Cu network obviously suppresses the charge transfer resistance. This result can be attributed to the fact that the Cu network ensures the LFP crystals to get electron easily, alleviating the electrode polarization in view of one-dimensional Li{sup +} ion mobility in the olivine crystals. Based on the analysis of Randles plots, the relatively higher Li{sup +} diffusion coefficient reflects the more efficient Li{sup +} pathway in the LFP powders through the aid of porous Cu network. - Highlights: • An efficient route was used to prepare Cu/LiFePO{sub 4} (LFP) hybrid as cathode material. • The Cu/LFP cathodes exhibit an improved performance as compared to fresh LFP one. • The microwave approach can deposit Cu network, fully covered the LFP powders. • The Cu network ensures LFP to get electrons, alleviating electrode polarization.

  6. Microwave synthesis of copper network onto lithium iron phosphate cathode materials for improved electrochemical performance

    International Nuclear Information System (INIS)

    Hsieh, Chien-Te; Liu, Juan-Ru; Juang, Ruey-Shin; Lee, Cheng-En; Chen, Yu-Fu

    2015-01-01

    Herein reported is an efficient microwave-assisted (MA) approach for growing Cu network onto LiFePO 4 (LFP) powders as cathode materials for high-performance Li-ion batteries. The MA approach is capable of depositing highly-porous Cu network, fully covered the LFP powders. The electrochemical performance of Cu-coated LFP cathodes are well characterized by charge/discharge cycling and electrochemical impedance spectroscopy (EIS). The Cu network acts as the key role in improving the specific capacity, rate capability, electrode polarization, as compared to fresh LFP cathode without the Cu coating. The EIS incorporated with equivalent circuit reveals that the completed Cu network obviously suppresses the charge transfer resistance. This result can be attributed to the fact that the Cu network ensures the LFP crystals to get electron easily, alleviating the electrode polarization in view of one-dimensional Li + ion mobility in the olivine crystals. Based on the analysis of Randles plots, the relatively higher Li + diffusion coefficient reflects the more efficient Li + pathway in the LFP powders through the aid of porous Cu network. - Highlights: • An efficient route was used to prepare Cu/LiFePO 4 (LFP) hybrid as cathode material. • The Cu/LFP cathodes exhibit an improved performance as compared to fresh LFP one. • The microwave approach can deposit Cu network, fully covered the LFP powders. • The Cu network ensures LFP to get electrons, alleviating electrode polarization

  7. Synthesis-microstructure-performance relationship of layered transition metal oxides as cathode for rechargeable sodium batteries prepared by high-temperature calcination.

    Science.gov (United States)

    Xie, Man; Luo, Rui; Lu, Jun; Chen, Renjie; Wu, Feng; Wang, Xiaoming; Zhan, Chun; Wu, Huiming; Albishri, Hassan M; Al-Bogami, Abdullah S; El-Hady, Deia Abd; Amine, Khalil

    2014-10-08

    Research on sodium batteries has made a comeback because of concern regarding the limited resources and cost of lithium for Li-ion batteries. From the standpoint of electrochemistry and economics, Mn- or Fe-based layered transition metal oxides should be the most suitable cathode candidates for affordable sodium batteries. Herein, this paper reports a novel cathode material, layered Na1+x(Fey/2Niy/2Mn1-y)1-xO2 (x = 0.1-0.5), synthesized through a facile coprecipitation process combined with subsequent calcination. For such cathode material calcined at 800 °C for 20 h, the Na/Na1+x(Fey/2Niy/2Mn1-y)1-xO2 (x = 0.4) electrode exhibited a good capacity of 99.1 mAh g(-1) (cycled at 1.5-4.0 V) and capacity retention over 87% after 50 cycles. Optimization of this material would make layered transition metal oxides a strong candidate for the Na-ion battery cathode.

  8. Is alpha-V2O5 a cathode material for Mg insertion batteries?

    Energy Technology Data Exchange (ETDEWEB)

    Sa, Niya; Wang, Hao; Proffit, Danielle L.; Lipson, Albert L.; Key, Baris; Liu, Miao; Feng, Zhenxing; Fister, Timothy T.; Ren, Yang; Sun, Cheng-Jun; Vaughey, John T.; Fenter, Paul A.; Persson, Kristin A.; Burrell, Anthony K.

    2016-08-01

    When designing a high energy density battery, one of the critical features is a high voltage, high capacity cathode material. In the development of Mg batteries, oxide cathodes that can reversibly intercalate Mg, while at the same time being compatible with an electrolyte that can deposit Mg reversibly are rare. Herein, we report the compatibility of Mg anodes with a-V2O5 by employing magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolytes at very low water levels. Electrolytes that contain a high water level do not reversibly deposit Mg, but interestingly these electrolytes appear to enable much higher capacities for an a-V2O5 cathode. Solid state NMR indicates that the major source of the higher capacity in high water content electrolytes originates from reversible proton insertion. In contrast, we found that lowering the water level of the magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolyte is critical to achieve reversible Mg deposition and direct evidence for reversible Mg intercalation is shown. Findings we report here elucidate the role of proton intercalation in water-containing electrolytes and clarify numerous conflicting reports of Mg insertion into a-V2O5.

  9. Targeted partial surface modification with nano-SiO2@Li2CoPO4F as high-voltage cathode material for LIBs

    Science.gov (United States)

    Chang, Caiyun; Huang, Zhipeng; Tian, Runsai; Jiang, Xinyu; Li, Chunsheng; Feng, Jijun

    2017-10-01

    Tuning whole/partial surface modification on cathode material with oxide material is a sought-after method to enhance the electrochemical performance in power storage field. Herein, nano-SiO2 targeted partial surface modified high voltage cathode material Li2CoPO4F has been successfully fabricated via a facile self-assembly process in silica dispersion at ambient temperature. With the aid of polar -OH groups attracted on the surface of SiO2 micelles, the nano-SiO2 preferentially nestle up along the borders and boundaries of Li2CoPO4F particles, where protection should be deployed with emphasis against the undesirable interactions between materials and electrolytes. Compared with pristine Li2CoPO4F, the SiO2 selectively modified Li2CoPO4F cathode materials, especially LCPF-3S, exhibit desirable electrochemical performances with higher discharge capacity, more outstanding cycle stability and favorable rate capability without any additional carbon involved. The greatly enhanced electrochemical properties can be attributed to the improved lithium-ion diffusion kinetics and structure tolerance during repeated lithiation/delithiation process. Such findings reveal a great potential of nano-SiO2 modified Li2CoPO4F as high energy cathode material for lithium ion batteries.

  10. Cathodic reduction of the duplex oxide films formed on copper in air with high relative humidity at 60 deg C

    International Nuclear Information System (INIS)

    Seo, M.; Ishikawa, Y.; Kodaira, M.; Sugimoto, A.; Nakayama, S.; Watanabe, M.; Furuya, S.; Minamitani, R.; Miyata, Y.; Nishikata, A.; Notoya, T.

    2005-01-01

    The cathodic reduction of duplex air-formed oxide film on copper was performed at a constant current density of i c = -50 μA cm -2 in deaerated 0.1 M KCl solution to investigate the sequence of cathodic reduction of each oxide layer and its mechanism. The single-phase thick CuO film on copper was also cathodically reduced at i c = -50 μA cm -2 or -2.5 mA cm -2 . The surface characterizations of the air-formed oxide film and single-phase CuO film before cathodic reduction and after partial or complete cathodic reduction were performed by XPS and X-ray diffraction, respectively. The two plateau regions appeared in the potential vs. time curve during cathodic reduction of the duplex air-formed oxide film on copper, while one plateau region was observed in the potential-time curve during cathodic reduction of the single-phase CuO film on copper. The potential in the first plateau region for the air-formed film coincided with that in the plateau region for the CuO film. The results of XPS and X-ray diffraction suggested that in the first plateau region, the outer CuO layer is directly reduced to metallic Cu, while in the second plateau region, the inner Cu 2 O layer is reduced to metallic Cu

  11. Nano Copper Oxide-Modified Carbon Cloth as Cathode for a Two-Chamber Microbial Fuel Cell.

    Science.gov (United States)

    Dong, Feng; Zhang, Peng; Li, Kexun; Liu, Xianhua; Zhang, Pingping

    2016-12-09

    In this work, Cu₂O nanoparticles were deposited on a carbon cloth cathode using a facile electrochemical method. The morphology of the modified cathode, which was characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) tests, showed that the porosity and specific surface area of the cathode improved with longer deposition times. X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) results showed that cupric oxide and cuprous oxide coexisted on the carbon cloth, which improved the electrochemical activity of cathode. The cathode with a deposition time of 100 s showed the best performance, with a power density twice that of bare carbon cloth. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) results revealed that moderate deposition of nano copper oxide on carbon cloth could dramatically reduce the charge transfer resistance, which contributed to the enhanced electrochemical performance. The mediation mechanism of copper oxide nanocatalyst was illustrated by the fact that the recycled conversion between cupric oxide and cuprous oxide accelerated the electron transfer efficiency on the cathode.

  12. Comparison of gap frame designs and materials for precision cathode strip chambers

    International Nuclear Information System (INIS)

    Horvath, J.A.; Pratuch, S.M.; Belser, F.C.

    1993-01-01

    Precision cathode strip chamber perimeter designs that incorporate either continuous or discrete-post gap frames are analyzed. The effects of ten design and material combinations on gravity sag, mass, stress, and deflected shape are evaluated. Procedures are recommended for minimizing mass in the chamber perimeter region while retaining structural integrity and electrical design latitude

  13. Nickel Hexacyanoferrate Nanoparticles as a Low Cost Cathode Material for Lithium-Ion Batteries

    International Nuclear Information System (INIS)

    Omarova, Marzhana; Koishybay, Aibolat; Yesibolati, Nulati; Mentbayeva, Almagul; Umirov, Nurzhan; Ismailov, Kairat; Adair, Desmond; Babaa, Moulay-Rachid; Kurmanbayeva, Indira; Bakenov, Zhumabay

    2015-01-01

    Potassium nickel hexacyanoferrate KNi[Fe(CN) 6 ] (NiHCF) was synthesized by a simple co-precipitation method and investigated as a cathode material for lithium-ion batteries. The X-ray diffraction and transmission electron microscopy studies revealed the formation of pure phase of agglomerated NiHCF nanoparticles of about 20–50 nm in size. The material exhibited stable cycling performance as a cathode in a lithium half-cell within a wide range of current densities, and a working potential around 3.3 V vs. Li + /Li. The lithium ion diffusion coefficient in this system was determined to be in a range of 10 −9 to 10 −8 cm 2 s −1 , which is within the values for the cathode materials for lithium-ion batteries with high rate capability. Considering promising electrochemical performance and attractive lithium-ion diffusion properties of this material along with its economical benefits and simplified preparation, NiHCF could be considered as a very promising cathode for large scale lithium-ion batteries.

  14. High Oxygen Reduction Reaction Performances of Cathode Materials Combining Polyoxometalates, Coordination Complexes, and Carboneous Supports.

    Science.gov (United States)

    Zhang, Shuangshuang; Oms, Olivier; Hao, Long; Liu, Rongji; Wang, Meng; Zhang, Yaqin; He, Hong-Yan; Dolbecq, Anne; Marrot, Jérôme; Keita, Bineta; Zhi, Linjie; Mialane, Pierre; Li, Bin; Zhang, Guangjin

    2017-11-08

    A series of carbonaceous-supported precious-metal-free polyoxometalate (POM)-based composites which can be easily synthesized on a large scale was shown to act as efficient cathode materials for the oxygen reduction reaction (ORR) in neutral or basic media via a four-electron mechanism with high durability. Moreover, exploiting the versatility of the considered system, its activity was optimized by the judicious choice of the 3d metals incorporated in the {(PW 9 ) 2 M 7 } (M = Co, Ni) POM core, the POM counterions and the support (thermalized triazine-based frameworks (TTFs), fluorine-doped TTF (TTF-F), reduced graphene oxide, or carbon Vulcan XC-72. In particular, for {(PW 9 ) 2 Ni 7 }/{Cu(ethylenediamine) 2 }/TTF-F, the overpotential required to drive the ORR compared well with those of Pt/C. This outstanding ORR electrocatalytic activity is linked with two synergistic effects due to the binary combination of the Cu and Ni centers and the strong interaction between the POM molecules and the porous and highly conducting TTF-F framework. To our knowledge, {(PW 9 ) 2 Ni 7 }/{Cu(ethylenediamine) 2 }/TTF-F represents the first example of POM-based noble-metal-free ORR electrocatalyst possessing both comparable ORR electrocatalytic activity and much higher stability than that of Pt/C in neutral medium.

  15. Building up an electrocatalytic activity scale of cathode materials for organic halide reductions

    International Nuclear Information System (INIS)

    Bellomunno, C.; Bonanomi, D.; Falciola, L.; Longhi, M.; Mussini, P.R.; Doubova, L.M.; Di Silvestro, G.

    2005-01-01

    A wide investigation on the electrochemical activity of four model organic bromides has been carried out in acetonitrile on nine cathodes of widely different affinity for halide anions (Pt, Zn, Hg, Sn, Bi, Pb, Au, Cu, Ag), and the electrocatalytic activities of the latter have been evaluated with respect to three possible inert reference cathode materials, i.e. glassy carbon, boron-doped diamond, and fluorinated boron-doped diamond. A general electrocatalytic activity scale for the process is proposed, with a discussion on its modulation by the configuration of the reacting molecule, and its connection with thermodynamic parameters accounting for halide adsorption

  16. Preparation and enhanced electrochemical properties of nano-sulfur/poly(pyrrole-co-aniline) cathode material for lithium/sulfur batteries

    International Nuclear Information System (INIS)

    Qiu Linlin; Zhang Shichao; Zhang Lan; Sun, Mingming; Wang Weikun

    2010-01-01

    Poly(pyrrole-co-aniline) (PPyA) copolymer nanofibers were prepared by chemical oxidation method with cetyltrimethyl ammonium chloride (CTAC) as template, and the nano-sulfur/poly(pyrrole-co-aniline) (S/PPyA) composite material in lithium batteries was achieved via co-heating the mixture of PPyA and sublimed sulfur at 160 deg. C for 24 h. The component and structure of the materials were characterized by FTIR, Raman, XRD, and SEM. PPyA with nanofiber network structure was employed as a conductive matrix, adsorbing agent and firm reaction chamber for the sulfur cathode materials. The nano-dispersed composite exhibited a specific capacity up to 1285 mAh g -1 in the initial cycle and remained 866 mAh g -1 after 40 cycles.

  17. Microwave irradiation controls the manganese oxidation states of nanostructured (Li[Li0.2Mn0.52Ni0.13Co0.13Al0.02]O2) layered cathode materials for high-performance lithium ion batteries

    CSIR Research Space (South Africa)

    Jafta, CJ

    2015-02-01

    Full Text Available A hybrid synthesis procedure, combining microwave irradiation and conventional annealing process, is described for the preparation of lithium-rich manganese-rich cathode materials, Li[Li0.2Mn0.54Ni0.13Co0.13]O2 (LMNC) and its aluminum...

  18. Electrochemical impedance spectroscopy investigation on indium tin oxide films under cathodic polarization in NaOH solution

    International Nuclear Information System (INIS)

    Gao, Wenjiao; Cao, Si; Yang, Yanze; Wang, Hao; Li, Jin; Jiang, Yiming

    2012-01-01

    The electrochemical corrosion behaviors of indium tin oxide (ITO) films under the cathodic polarization in 0.1 M NaOH solution were investigated by electrochemical impedance spectroscopy. The as-received and the cathodically polarized ITO films were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction for morphological, compositional and structural studies. The results showed that ITO films underwent a corrosion process during the cathodic polarization and the main component of the corrosion products was body-centered cubic indium. The electrochemical impedance parameters were related to the effect of the cathodic polarization on the ITO specimens. The capacitance of ITO specimens increased, while the charge transfer resistance and the inductance decreased with the increase of the polarization time. The proposed mechanism indicated that the corrosion products (metallic indium) were firstly formed during the cathodic polarization and then absorbed on the surface of the ITO film. As the surface was gradually covered by indium particles, the corrosion process was suppressed. - Highlights: ► Cathodic polarization of indium tin oxide (ITO) in 0.1 M NaOH. ► Cathodic polarization studied with electrochemical impedance spectroscopy. ► ITO underwent a corrosion attack during cathodic polarization, indium was observed. ► Electrochemical parameters of ITO were obtained using equivalent electrical circuit. ► A corrosion mechanism is proposed.

  19. Fabrication of polypyrrole/vanadium oxide nanotube composite with enhanced electrochemical performance as cathode in rechargeable batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiaowei, E-mail: zhouxiaowei@ynu.edu.cn [Department of Physics, School of Physics and Astronomy, Yunnan University, Kunming 650504, Yunnan (China); Chen, Xu; He, Taoling; Bi, Qinsong [Department of Physics, School of Physics and Astronomy, Yunnan University, Kunming 650504, Yunnan (China); Sun, Li [Department of Physics, School of Physics and Astronomy, Yunnan University, Kunming 650504, Yunnan (China); Department of Mechanical Engineering, University of Houston, Houston 77204, TX (United States); Liu, Zhu, E-mail: zhuliu@ynu.edu.cn [Department of Physics, School of Physics and Astronomy, Yunnan University, Kunming 650504, Yunnan (China); Yunnan Key Laboratory of Micro/Nano-Materials and Technology, Yunnan University, Kunming 650091, Yunnan (China)

    2017-05-31

    Highlights: • VO{sub x}NTs were hydrothermally prepared using C{sub 12}H{sub 27}N as soft template with scalability. • Polypyrrole/VO{sub x}NTs with less C{sub 12}H{sub 27}N template and higher conductivity were obtained. • Polypyrrole/VO{sub x}NTs exhibit better performance as cathode for LIBs compared to VO{sub x}NTs. • Further modification to VO{sub x}NTs with desired electrochemical property can be expected. - Abstract: Vanadium oxide nanotubes (VO{sub x}NTs) with hollow as well as multi-walled features were fabricated under hydrothermal condition by soft-template method. This novel VO{sub x}NTs can be used as cathode material for lithium ion batteries (LIBs), but displaying low specific capacity and poor cycling performance owing to the residual of a mass of soft-template (C{sub 12}H{sub 27}N) and intrinsic low conductivity of VO{sub x}. Cation exchange technique and oxidative polymerization process of pyrrole monomers were conducted to wipe off partial soft-template without electrochemical activity within VO{sub x}NTs and simultaneously form polypyrrole coating on VO{sub x}NTs, respectively. The resulting polypyrrole/VO{sub x}NTs nanocomposite delivers much improved capacity and cyclic stability. Further optimizations, such as complete elimination of organic template and enhancing the crystallinity, can make this unique nanostructure a promising cathode for LIBs.

  20. Kinetics of oxygen reduction in perovskite cathodes for solid oxide fuel cells: A combined modeling and experimental approach

    Science.gov (United States)

    Miara, Lincoln James

    Solid oxide fuel cells (SOFCs) have the potential to replace conventional stationary power generation technologies; however, there are major obstacles to commercialization, the most problematic of which is poor cathode performance. Commercialization of SOFCs will follow when the mechanisms occurring at the cathode are more thoroughly understood and adapted for market use. The catalytic reduction of oxygen occurring in SOFC cathodes consists of many elementary steps such as gas phase diffusion, chemical and/or electrochemical reactions which lead to the adsorption and dissociation of molecular oxygen onto the cathode surface, mass transport of oxygen species along the surface and/or through the bulk of the cathode, and full reduction and incorporation of the oxygen at the cathode/electrolyte two or three phase boundary. Electrochemical impedance spectroscopy (EIS) is the main technique used to identify the occurrence of these different processes, but when this technique is used without an explicit model describing the kinetics it is difficult to unravel the interdependence of each of these processes. The purpose of this dissertation is to identify the heterogeneous reactions occurring at the cathode of an SOFC by combining experimental EIS results with mathematical models describing the time dependent behavior of the system. This analysis is performed on two different systems. In the first case, experimental EIS results from patterned half cells composed of Ca-doped lanthanum manganite (LCM)| yttria-doped ZrO2 (YSZ) are modeled to investigate the temperature and partial pressure of oxygen, pO2, dependence of oxygen adsorption/dissociation onto the LCM surface, surface diffusion of atomic oxygen, and electrochemical reduction and incorporation of the oxygen into the electrolyte in the vicinity of the triple phase boundary (TPB). This model determines the time-independent state-space equations from which the Faradaic admittance transfer function is obtained. The

  1. Highly Graphitic Carbon Nanofibers Web as a Cathode Material for Lithium Oxygen Batteries

    Directory of Open Access Journals (Sweden)

    Hyungkyu Han

    2018-01-01

    Full Text Available The lithium oxygen battery is a promising energy storage system due to its high theoretical energy density and ability to use oxygen from air as a “fuel”. Although various carbonaceous materials have been widely used as a cathode material due to their high electronic conductivity and facial processability, previous studies mainly focused on the electrochemical properties associated with the materials (such as graphene and carbon nanotubes and the electrode configuration. Recent reports demonstrated that the polarization associated with cycling could be significantly increased by lithium carbonates generated from the reaction between the carbon cathode and an electrolyte, which indicates that the physicochemical properties of the carbon cathode could play an important role on the electrochemical performances. However, there is no systematic study to understand these phenomena. Here, we systematically explore the electrochemical properties of carbon nanofibers (CNF webs with different graphitization degree as a cathode for Li oxygen batteries. The physicochemical properties and electrochemical properties of CNF webs were carefully monitored before and after cycling. CNF webs are prepared at 1000, 1200 and 1400 °C. CNF web pyrolyzed at 1400 °C shows lowered polarization and improved cycle retention compared to those of CNF webs pyrolyzed at 1000 and 1200 °C.

  2. Highly durable anode supported solid oxide fuel cell with an infiltrated cathode

    DEFF Research Database (Denmark)

    Samson, Alfred Junio; Hjalmarsson, Per; Søgaard, Martin

    2012-01-01

    An anode supported solid oxide fuel cell with an La0.6Sr0.4Co1.05O3_δ (LSC) infiltrated-Ce0.9Gd0.1O1.95 (CGO) cathode that shows a stable performance has been developed. The cathode was prepared by screen printing a porous CGO backbone on top of a laminated and co-fired anode supported half cell...... was tested at 700 deg. C under a current density of 0.5 A cm-2 for 1500 h using air as oxidant and humidified hydrogen as fuel. The electrochemical performance of the cell was analyzed by impedance spectroscopy and current evoltage relationships. No measurable degradation in the cell voltage or increase...... in the resistance from the recorded impedance was observed during long term testing. The power density reached 0.79Wcm-2 at a cell voltage of 0.6 V at 750 deg. C. Post test analysis of the LSC infiltrated-CGO cathode by scanning electron microscopy revealed no significant micro-structural difference...

  3. Tantalum oxide-based compounds as new non-noble cathodes for polymer electrolyte fuel cell

    International Nuclear Information System (INIS)

    Ishihara, Akimitsu; Tamura, Motoko; Matsuzawa, Koichi; Mitsushima, Shigenori; Ota, Ken-ichiro

    2010-01-01

    Tantalum oxide-based compounds were examined as new non-noble cathodes for polymer electrolyte fuel cell. Tantalum carbonitride powder was partially oxidized under a trace amount of oxygen gas at 900 o C for 4 or 8 h. Onset potential for oxygen reduction reaction (ORR) of the specimen heat-treated for 8 h was 0.94 V vs. reversible hydrogen electrode in 0.1 mol dm -3 sulfuric acid at 30 o C. The partial oxidation of tantalum carboniride was effective to enhance the catalytic activity for the ORR. The partially oxidized specimen with highest catalytic activity had ca. 5.25 eV of ionization potential, indicating that there was most suitable strength of the interaction of oxygen and tantalum on the catalyst surface.

  4. Nanoscale surface modification of Li-rich layered oxides for high-capacity cathodes in Li-ion batteries

    Science.gov (United States)

    Lan, Xiwei; Xin, Yue; Wang, Libin; Hu, Xianluo

    2018-03-01

    Li-rich layered oxides (LLOs) have been developed as a high-capacity cathode material for Li-ion batteries, but the structural complexity and unique initial charging behavior lead to several problems including large initial capacity loss, capacity and voltage fading, poor cyclability, and inferior rate capability. Since the surface conditions are critical to electrochemical performance and the drawbacks, nanoscale surface modification for improving LLO's properties is a general strategy. This review mainly summarizes the surface modification of LLOs and classifies them into three types of surface pre-treatment, surface gradient doping, and surface coating. Surface pre-treatment usually introduces removal of Li2O for lower irreversible capacity while surface doping is aimed to stabilize the structure during electrochemical cycling. Surface coating layers with different properties, protective layers to suppress the interface side reaction, coating layers related to structural transformation, and electronic/ionic conductive layers for better rate capability, can avoid the shortcomings of LLOs. In addition to surface modification for performance enhancement, other strategies can also be investigated to achieve high-performance LLO-based cathode materials.

  5. Redox-reversible perovskite ferrite cathode for high temperature solid oxide steam electrolyser

    International Nuclear Information System (INIS)

    Li, Zhe; Li, Shisong; Tseng, Chung-Jen; Tao, Shanwen; Xie, Kui

    2017-01-01

    Highlights: • Redox reversible ferrite cathode is demonstrated for solid oxide electrolyser. • Promising electrical conductivity is obtained with Pr doping in hydrogen. • High performance of steam electrolysis is achieved with ferrite cathode. - Abstract: In this work, perovskite Sr 1−x Pr x FeO 3-δ (SPF) (x = 0.02, 0.04, 0.06, 0.08 and 0.10) are investigated and employed as solid oxide steam electrolyser cathode at 800 °C. X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM) analysis together indicate that the Sr 1−x Pr x FeO 3-δ is redox reversible with a phase transition from cubic to orthorhombic structure in redox cycles. The doping of Pr in A site has remarkably enhanced the electronic conduction to 1.0–1.2 S cm −1 at intermediate temperatures in reducing atmosphere. Electrochemical measurements demonstrate that the polarization resistance with Sr 0.96 Pr 0.04 FeO 3-δ electrode shows the lowest values of 0.25 Ω cm 2 in symmetric cells in reducing atmosphere at 800 °C. Direct steam electrolysis with Sr 0.96 Pr 0.04 FeO 3-δ cathode shows a current density of 1.64 A cm −2 at 2.0 V when fed with 5%H 2 O/Ar. The hydrogen production rate reaches 4.73, 6.68, 8.35 and 10.23 mL min −1 cm −2 at 1.4, 1.6, 1.8, 2.0 V, respectively, while the highest Faraday efficiency is as high as 97.16% at 1.8 V.

  6. Structural and Chemical Evolution of Li- and Mn-rich Layered Cathode Material

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jianming; Xu, Pinghong; Gu, Meng; Xiao, Jie; Browning, Nigel D.; Yan, Pengfei; Wang, Chong M.; Zhang, Jiguang

    2015-02-24

    Lithium (Li)- and manganese-rich (LMR) layered-structure materials are very promising cathodes for high energy density lithium-ion batteries. However, their voltage fading mechanism and its relationships with fundamental structural changes are far from being sufficiently understood. Here we report the detailed phase transformation pathway in the LMR cathode (Li[Li0.2Ni0.2Mn0.6]O2) during cycling for the samples prepared by hydro-thermal assistant method. It is found the transformation pathway of LMR cathode is closely correlated to its initial structure and preparation conditions. The results reveal that LMR cathode prepared by HA approach experiences a phase transformation from the layered structure to a LT-LiCoO2 type defect spinel-like structure (Fd-3m space group) and then to a disordered rock-salt structure (Fm-3m space group). The voltage fade can be well correlated with the Li ion insertion into octahedral sites, rather than tetrahedral sites, in both defect spinel-like structure and disordered rock-salt structure. The reversible Li insertion/removal into/from the disordered rock-salt structure is ascribed to the Li excess environment that can satisfy the Li percolating in the disordered rock-salt structure despite the increased kinetic barrier. Meanwhile, because of the presence of a great amount of oxygen vacancies, a significant decrease of Mn valence is detected in the cycled particle, which is below that anticipated for a potentially damaging Jahn-Teller distortion (+3.5). Clarification of the phase transformation pathway, cation redistribution, oxygen vacancy and Mn valence change undoubtedly provides insights into a profound understanding on the voltage fade, and capacity degradation of LMR cathode. The results also inspire us to further enhance the reversibility of LMR cathode via improving its surface structural stability.

  7. Mechanochemically prepared ternary hybrid cathode material for lithium batteries

    International Nuclear Information System (INIS)

    Posudievsky, Oleg Yu; Kozarenko, Olga A.; Dyadyun, Vyacheslav S.; Jorgensen, Scott W.; Spearot, James A.; Koshechko, Vyacheslav G.; Pokhodenko, Vitaly D.

    2013-01-01

    Graphical abstract: The presence of macromolecules of an ion-conducting polymer in the composition of the ternary nanocomposite PPy–PEO/V 2 O 5 promotes interfacial transfer of lithium ions and also facilitates faster transport inside the particles of the nanocomposite. -- Highlights: • Two- and three component nanocomposites are prepared via a solvent-free mechanochemical synthesis. • The nanocomposites retain their capacity above 200 mA h g −1 for at least one hundred cycles. • The presence of PEO promotes interfacial transfer of lithium ions and facilitates faster transport inside the nanocomposite. -- Abstract: Ternary host–guest nanocomposite based on vanadium oxide and two polymers with different types of conductivity (ionic and electronic) – polypyrrole (PPy) and polyethylene oxide (PEO) – is prepared by solventless mechanochemical synthesis. The nanocomposite can be reversibly cycled with a specific capacity of ∼200 mA h g −1 for at least one hundred cycles of full charge–discharge as the active component of the positive electrode of lithium batteries. Electrochemical performance of ternary PPy 0.1 PEO 0.15 V 2 O 5 is compared with two-component analog PPy 0.1 V 2 O 5 . The presence of macromolecules of an ion-conducting polymer in the composition of the ternary nanocomposite PPy 0.1 PEO 0.15 V 2 O 5 promotes interfacial transfer of lithium ions and also facilitates faster transport inside the particles of the nanocomposite

  8. Deposition and characterization of thin films of materials with application in cathodes for lithium rechargeable micro batteries

    International Nuclear Information System (INIS)

    Lopez I, J.

    2007-01-01

    In this thesis work is reported the deposition and characterization of thin films of materials of the type LiMO 2 , with M=Co and Ni, which have application in cathodes for micro-batteries of lithium ions. In the last years some investigators have reported that the electrochemical operation of the lithium ions batteries it can improve recovering the cathode, in bundle form, with some metal oxides as the Al 2 O 3 ; for that the study of the formation of thin films in bilayer form LiMO 2 /AI 2 O 3 is of interest in the development of lithium ions micro batteries. The thin films were deposited using the laser ablation technique studying the effect of some deposit parameters in the properties of the one formed material, as: laser fluence, substrate temperature and working atmosphere, with the purpose of optimizing it. In the case of the LiCoO 2 it was found that to use an inert atmosphere of argon allows to obtain the material with the correct composition. Additionally, with the use of a temperature in the substrate of 150 C is possible to obtain to the material with certain crystallinity grade that to the subjected being to a post-deposit thermal treatment at 300 C for three hours, it gives as result a totally crystalline material. In the case of the thin films of LiNiO 2 , it was necessary to synthesize the oxide starting from a reaction of solid state among nickel oxide (NiO) and lithium oxide (Li 2 O) obtaining stoichiometric LiNiO 2 . For the formation of the thin films of LiNiO 2 it was used an argon atmosphere and the laser fluence was varied, the deposits were carried out to two different substrates temperatures, atmosphere and 160 C. In both cases the material it was recovered with an alumina layer, found that this layer didn't modify the structural properties of the base oxide (LiCoO 2 and LiNiO 2 ). (Author)

  9. Four-electron transfer tandem tetracyanoquinodimethane for cathode-active material in lithium secondary battery

    Science.gov (United States)

    Kurimoto, Naoya; Omoda, Ryo; Mizumo, Tomonobu; Ito, Seitaro; Aihara, Yuichi; Itoh, Takahito

    2018-02-01

    Quinoid compounds are important candidates of organic active materials for lithium-ion batteries. However, its high solubility to organic electrolyte solutions and low redox potential are known as their major drawbacks. To circumvent these issues, we have designed and synthesized a tandem-tetracyanoquinonedimethane type cathode-active material, 11,11,12,12,13,13,14,14-octacyano-1,4,5,8-anthradiquinotetramethane (OCNAQ), that has four redox sites per molecule, high redox potential and suppressed solubility to electrolyte solution. Synthesized OCNAQ has been found to have two-step redox reactions by cyclic voltammetry, and each step consists of two-electron reactions. During charge-discharge tests using selected organic cathode-active materials with a lithium metal anode, the cell voltages obtained from OCNAQ are higher than those for 11,11-dicyanoanthraquinone methide (AQM) as expected, due to the strong electron-withdrawing effect of the cyano groups. Unfortunately, even with the use of the organic active material, the issue of dissolution to the electrolyte solution cannot be suppressed completely; however, appropriate choice of the electrolyte solutions, glyme-based electrolyte solutions in this study, give considerable improvement of the cycle retention (98% and 56% at 10 and 100 cycles at 0.5C, respectively). The specific capacity and energy density obtained in this study are 206 mAh g-1 and 554 mWh g-1 with respect to the cathode active material.

  10. Innovative application of ionic liquid to separate Al and cathode materials from spent high-power lithium-ion batteries.

    Science.gov (United States)

    Zeng, Xianlai; Li, Jinhui

    2014-04-30

    Because of the increasing number of electric vehicles, there is an urgent need for effective recycling technologies to recapture the significant amount of valuable metals contained in spent lithium-ion batteries (LiBs). Previous studies have indicated, however, that Al and cathode materials were quite difficult to separate due to the strong binding force supplied by the polyvinylidene fluoride (PVDF), which was employed to bind cathode materials and Al foil. This research devoted to seek a new method of melting the PVDF binder with heated ionic liquid (IL) to separate Al foil and cathode materials from the spent high-power LiBs. Theoretical analysis based on Fourier's law was adopted to determine the heat transfer mechanism of cathode material and to examine the relationship between heating temperature and retention time. All the experimental and theoretic results show that peel-off rate of cathode materials from Al foil could reach 99% when major process parameters were controlled at 180°C heating temperature, 300 rpm agitator rotation, and 25 min retention time. The results further imply that the application of IL for recycling Al foil and cathode materials from spent high-power LiBs is highly efficient, regardless of the application source of the LiBs or the types of cathode material. This study endeavors to make a contribution to an environmentally sound and economically viable solution to the challenge of spent LiB recycling. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Novel layered perovskite GdBaCoFeO{sub 5+{delta}} as a potential cathode for proton-conducting solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Hanping; Xue, Xingjian [Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2010-05-15

    While cobalt-containing perovskite-type cathode materials facilitate the activation of oxygen reduction, they also suffer from problems like poor chemical stability in CO{sub 2}, high thermal expansion coefficients, etc. Partial B site substitution with Fe element is expected to be able to mitigate these problems while keeping high catalyst performance. In this paper, a layered perovskite GdBaCoFeO{sub 5+{delta}} (GBCF) was developed as a cathode material for protonic ceramic membrane fuel cells (PCMFCs) based on proton-conducting electrolyte of stable BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{delta}} (BZCY7). The button cells of Ni-BZCY7 vertical stroke BZCY7 vertical stroke GBCF were fabricated and tested from 600 to 700 C with humidified H{sub 2} ({proportional_to}3% H{sub 2}O) as a fuel and ambient oxygen as oxidant. An open-circuit potential of 1.002 V, maximum power density of 482 mW cm{sup -2}, and a low electrode polarization resistance of 0.11 {omega}cm{sup 2} were achieved at 700 C. The experimental results indicated that the layered perovskite GBCF is a good candidate for cathode material, while the developed Ni-BZCY7 vertical stroke BZCY7 vertical stroke GBCF cell is a promising functional material system for intermediate temperature solid oxide fuel cells. (author)

  12. A niobium and tantalum co-doped perovskite cathode for solid oxide fuel cells operating below 500 °C

    Science.gov (United States)

    Li, Mengran; Zhao, Mingwen; Li, Feng; Zhou, Wei; Peterson, Vanessa K.; Xu, Xiaoyong; Shao, Zongping; Gentle, Ian; Zhu, Zhonghua

    2017-01-01

    The slow activity of cathode materials is one of the most significant barriers to realizing the operation of solid oxide fuel cells below 500 °C. Here we report a niobium and tantalum co-substituted perovskite SrCo0.8Nb0.1Ta0.1O3−δ as a cathode, which exhibits high electroactivity. This cathode has an area-specific polarization resistance as low as ∼0.16 and ∼0.68 Ω cm2 in a symmetrical cell and peak power densities of 1.2 and 0.7 W cm−2 in a Gd0.1Ce0.9O1.95-based anode-supported fuel cell at 500 and 450 °C, respectively. The high performance is attributed to an optimal balance of oxygen vacancies, ionic mobility and surface electron transfer as promoted by the synergistic effects of the niobium and tantalum. This work also points to an effective strategy in the design of cathodes for low-temperature solid oxide fuel cells. PMID:28045088

  13. Co-flow anode/cathode supply heat exchanger for a solid-oxide fuel cell assembly

    Science.gov (United States)

    Haltiner, Jr., Karl J.; Kelly, Sean M.

    2005-11-22

    In a solid-oxide fuel cell assembly, a co-flow heat exchanger is provided in the flow paths of the reformate gas and the cathode air ahead of the fuel cell stack, the reformate gas being on one side of the exchanger and the cathode air being on the other. The reformate gas is at a substantially higher temperature than is desired in the stack, and the cathode gas is substantially cooler than desired. In the co-flow heat exchanger, the temperatures of the reformate and cathode streams converge to nearly the same temperature at the outlet of the exchanger. Preferably, the heat exchanger is formed within an integrated component manifold (ICM) for a solid-oxide fuel cell assembly.

  14. Synthesis and investigation of novel cathode materials for sodium ion batteries

    Science.gov (United States)

    Sawicki, Monica

    Environmental pollution and eventual depletion of fossil fuels and lithium has increased the need for research towards alternative electrical energy storage systems. In this context, research in sodium ion batteries (NIBs) has become more prevalent since the price in lithium has increased due to its demand and reserve location. Sodium is an abundant resource that is low cost, and safe; plus its chemical properties are similar to that of Li which makes the transition into using Na chemistry for ion battery systems feasible. In this study, we report the effects of processing conditions on the electrochemical properties of Na-ion batteries made of the NaCrO2 cathode. NaCrO2 is synthesized via solid state reactions. The as-synthesized powder is then subjected to high-energy ball milling under different conditions which reduces particle size drastically and causes significant degradation of the specific capacity for NaCrO2. X-ray diffraction reveals that lattice distortion has taken place during high-energy ball milling and in turn affects the electrochemical performance of the cathode material. This study shows that a balance between reducing particle size and maintaining the layered structure is essential to obtain high specific capacity for the NaCrO2 cathode. In light of the requirements for grid scale energy storage: ultra-long cycle life (> 20,000 cycles and calendar life of 15 to 20 years), high round trip efficiency (> 90%), low cost, sufficient power capability, and safety; the need for a suitable cathode materials with excellent capacity retention such as Na2MnFe(CN)6 and K2MnFe(CN)6 will be investigated. Prussian blue (A[FeIIIFeII (CN)6]•xH2O, A=Na+ or K+ ) and its analogues have been investigated as an alkali ion host for use as a cathode material. Their structure (FCC) provides large ionic channels along the direction enabling facile insertion and extraction of alkali ions. This material is also capable of more than one Na ion insertion per unit formula

  15. Naphthalene Diimide Based n-Type Conjugated Polymers as Efficient Cathode Interfacial Materials for Polymer and Perovskite Solar Cells.

    Science.gov (United States)

    Jia, Tao; Sun, Chen; Xu, Rongguo; Chen, Zhiming; Yin, Qingwu; Jin, Yaocheng; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2017-10-18

    A series of naphthalene diimide (NDI) based n-type conjugated polymers with amino-functionalized side groups and backbones were synthesized and used as cathode interlayers (CILs) in polymer and perovskite solar cells. Because of controllable amine side groups, all the resulting polymers exhibited distinct electronic properties such as oxidation potential of side chains, charge carrier mobilities, self-doping behaviors, and interfacial dipoles. The influences of the chemical variation of amine groups on the cathode interfacial effects were further investigated in both polymer and perovskite solar cells. We found that the decreased electron-donating property and enhanced steric hindrance of amine side groups substantially weaken the capacities of altering the work function of the cathode and trap passivation of the perovskite film, which induced ineffective interfacial modifications and declining device performance. Moreover, with further improvement of the backbone design through the incorporation of a rigid acetylene spacer, the resulting polymers substantially exhibited an enhanced electron-transporting property. Upon use as CILs, high power conversion efficiencies (PCEs) of 10.1% and 15.2% were, respectively, achieved in polymer and perovskite solar cells. Importantly, these newly developed n-type polymers were allowed to be processed over a broad thickness range of CILs in photovoltaic devices, and a prominent PCE of over 8% for polymer solar cells and 13.5% for perovskite solar cells can be achieved with the thick interlayers over 100 nm, which is beneficial for roll-to-roll coating processes. Our findings contribute toward a better understanding of the structure-performance relationship between CIL material design and solar cell performance, and provide important insights and guidelines for the design of high-performance n-type CIL materials for organic and perovskite optoelectronic devices.

  16. Arcjet cathode phenomena

    Science.gov (United States)

    Curran, Francis M.; Haag, Thomas W.; Raquet, John F.

    1989-01-01

    Cathode tips made from a number of different materials were tested in a modular arcjet thruster in order to examine cathode phenomena. Periodic disassembly and examination, along with the data collected during testing, indicated that all of the tungsten-based materials behaved similarly despite the fact that in one of these samples the percentage of thorium oxide was doubled and another was 25 percent rhenium. The mass loss rate from a 2 percent thoriated rhenium cathode was found to be an order of magnitude greater than that observed using 2 percent thoriated tungsten. Detailed analysis of one of these cathode tips showed that the molten crater contained pure tungsten to a depth of about 150 microns. Problems with thermal stress cracking were encountered in the testing of a hafnium carbide tip. Post test analysis showed that the active area of the tip had chemically reacted with the propellant. A 100 hour continuous test was run at about 1 kW. Post test analysis revealed no dendrite formation, such as observed in a 30 kW arcjet lifetest, near the cathode crater. The cathodes from both this test and a previously run 1000 hour cycled test displayed nearly identical arc craters. Data and calculations indicate that the mass losses observed in testing can be explained by evaporation.

  17. Chromium poisoning in (La,Sr)MnO3 cathode: Three-dimensional simulation of a solid oxide fuel cell

    OpenAIRE

    Miyoshi, Kota; Iwai, Hiroshi; Kishimoto, Masashi; Saito, Motohiro; Yoshida, Hideo

    2016-01-01

    A three-dimensional numerical model of a single solid oxide fuel cell (SOFC) considering chromium poisoning on the cathode side has been developed to investigate the evolution of the SOFC performance over long-term operation. The degradation model applied in the simulation describes the loss of the cathode electrochemical activity as a decrease in the active triple-phase boundary (TPB) length. The calculations are conducted for two types of cell: lanthanum strontium manganite (LSM)/yttria-sta...

  18. Cathode Materials for High Energy Density Lithium Batteries

    Directory of Open Access Journals (Sweden)

    Lefèvre G.

    2017-01-01

    Li2MnSiO4 has a large theoretical specific capacity (333 mAh/g through exchange of 2 lithium ions per formula unit. The thermal stability due to strong Si-O bonds makes LiMnSiO a very promising material for future energy storage in space applications. Preparation in inert atmosphere showed beneficial improvements of LMSO’s electrochemical properties. Nano-sizing and carbon coating have been effective ways to improve electronic conductivity and therefore electrochemical performance. Up to 1.66 Li per formula unit can be re-inserted in the 1st cycle. XRD analysis showed complete amorphization of Li2MnSiO4 after the 1st charge at 4.8 V with complete modification of the charge/discharge curves in the next cycles. Increasing the carbon coating ratio limits capacity loss during cycling but did not avoid amorphization. Finally influence of voltage window on structure stability was investigated. Careful choice of upper limit voltage has been showed to stabilize Li2MnSiO4 structure but for now is still limited to low Li+ insertion/extraction from the host material.

  19. Synthetic Control of Kinetic Reaction Pathway and Cationic Ordering in High-Ni Layered Oxide Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dawei [Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton NY 11973 USA; Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory Physical Chemistry Solid Surfaces, Department of Chemistry, Xiamen University, Xiamen Fujian 361005 China; Kou, Ronghui [X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne IL 60439 USA; Ren, Yang [X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne IL 60439 USA; Sun, Cheng-Jun [X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne IL 60439 USA; Zhao, Hu [Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton NY 11973 USA; Zhang, Ming-Jian [Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton NY 11973 USA; School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen Guangdong 518055 P. R. China; Li, Yan [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne IL 60439 USA; Huq, Ashifia [Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge TN 37831 USA; Ko, J. Y. Peter [The Cornell High Energy Synchrotron Source, Cornell University, Ithaca NY 14853 USA; Pan, Feng [School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen Guangdong 518055 P. R. China; Sun, Yang-Kook [Department of Energy Engineering, Hanyang University, Seoul 133-791 South Korea; Yang, Yong [Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory Physical Chemistry Solid Surfaces, Department of Chemistry, Xiamen University, Xiamen Fujian 361005 China; Amine, Khalil [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne IL 60439 USA; Bai, Jianming [National Synchrotron Light Source II, Brookhaven National Laboratory, Upton NY 11973 USA; Chen, Zonghai [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne IL 60439 USA; Wang, Feng [Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton NY 11973 USA

    2017-08-25

    Nickel-rich layered transition metal oxides, LiNi1-x(MnCo)(x)O-2 (1-x >= 0.5), are appealing candidates for cathodes in next-generation lithium-ion batteries (LIBs) for electric vehicles and other large-scale applications, due to their high capacity and low cost. However, synthetic control of the structural ordering in such a complex quaternary system has been a great challenge, especially in the presence of high Ni content. Herein, synthesis reactions for preparing layered LiNi0.7Mn0.15Co0.15O2 (NMC71515) by solid-state methods are investigated through a combination of time-resolved in situ high-energy X-ray diffraction and absorption spectroscopy measurements. The real-time observation reveals a strong temperature dependence of the kinetics of cationic ordering in NMC71515 as a result of thermal-driven oxidation of transition metals and lithium/oxygen loss that concomitantly occur during heat treatment. Through synthetic control of the kinetic reaction pathway, a layered NMC71515 with low cationic disordering and a high reversible capacity is prepared in air. The findings may help to pave the way for designing high-Ni layered oxide cathodes for LIBs.

  20. Sulfurized carbon: a class of cathode materials for high performance lithium/sulfur batteries

    Directory of Open Access Journals (Sweden)

    Sheng S. Zhang

    2013-12-01

    Full Text Available Liquid electrolyte lithium/sulfur (Li/S batteries cannot come into practical applications because of many problems such as low energy efficiency, short cycle life, and fast self-discharge. All these problems are related to the dissolution of lithium polysulfide, a series of sulfur reduction intermediates, in the liquid electrolyte, and resulting parasitic reactions with the Li anode. Covalently binding sulfur onto carbon surface is a solution to completely eliminate the dissolution of lithium polysulfide and make the Li/S battery viable for practical applications. This can be achieved by replacing elemental sulfur with sulfurized carbon as the cathode material. This article reviews the current efforts on this subject and discusses the syntheses, electrochemical properties, and prospects of the sulfurized carbon as a cathode material in the rechargeable Li/S batteries.

  1. Electrocoagulation of whey acids: anode and cathode materials, electroactive area and polarization curves

    Directory of Open Access Journals (Sweden)

    Francisco Prieto Garcia

    2017-06-01

    Full Text Available Anode (Al and Fe and cathode (graphite and Ti/RuO2 materials have been tested for electrocoagulation (EC and purification of the acid whey. The electroactive areas (EA of electrodes were calculated by the double layer capacitance method. Experiments were performed by cyclic voltammetry, chronoamperometry and polarization experiments. Among cathodic materials, the Ti/RuO2 electrode showed higher EA (2167 cm2 than graphite (1560 cm2. The Fe anode was found more stable than Al with greater charge transfer carried out in less time. Correlation of these results with those obtained during preliminary tests confirmed high removals (79 % in 8 h. For the Al electrode, 24 h were required to achieve efficiency of 49 %.

  2. Mesoporous nitrogen-rich carbon materials as cathode catalysts in microbial fuel cells

    KAUST Repository

    Ahn, Yongtae

    2014-12-01

    The high cost of the catalyst material used for the oxygen reduction reaction in microbial fuel cell (MFC) cathodes is one of the factors limiting practical applications of this technology. Mesoporous nitrogen-rich carbon (MNC), prepared at different temperatures, was examined as an oxygen reduction catalyst, and compared in performance to Pt in MFCs and electrochemical cells. MNC calcined at 800 °C produced a maximum power density of 979 ± 131 mW m-2 in MFCs, which was 37% higher than that produced using MNC calined at 600 °C (715 ± 152 mW m-2), and only 14% lower than that obtained with Pt (1143 ± 54 mW m-2). The extent of COD removal and coulombic efficiencies were the same for all cathode materials. These results show that MNC could be used as an alternative to Pt in MFCs. © 2014 Elsevier B.V. All rights reserved.

  3. Electron-deficient anthraquinone derivatives as cathodic material for lithium ion batteries

    Science.gov (United States)

    Takeda, Takashi; Taniki, Ryosuke; Masuda, Asuna; Honma, Itaru; Akutagawa, Tomoyuki

    2016-10-01

    We studied the electronic and structural properties of electron-deficient anthraquinone (AQ) derivatives, Me4N4AQ and TCNAQ, and investigated their charge-discharge properties in lithium ion batteries along with those of AQ. Cyclic voltammogram, X-ray structure analysis and theoretical calculations revealed that these three acceptors have different features, such as different electron-accepting properties with different reduction processes and lithium coordination abilities, and different packing arrangements with different intermolecular interactions. These differences greatly affect the charge-discharge properties of lithium ion batteries that use these compounds as cathode materials. Among these compounds, Me4N4AQ showed a high charge/discharge voltage (2.9-2.5 V) with high cyclability (>65% of the theoretical capacity after 30 cycles; no decrease after 15 cycles). These results provide insight into more in-depth design principles for lithium ion batteries using AQ derivatives as cathodic materials.

  4. Challenge of non-precious metal oxide-based cathode for polymer electrolyte fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Akimitsu; Matsuzawa, Koichi; Mitsushima, Shigenori; Ota, Ken-ichiro [Yokohama National Univ. (Japan)

    2010-07-01

    The partially oxidized TaC{sub 0.58}N{sub 0.42} was investigated as non-platinum cathode for PEFC. In order to quantify the degree of oxidation, the degree of oxidation (DOO) was defined using the XRD peaks of Ta-CN and Ta{sub 2}O{sub 5}. The onset potential for the oxidation reduction reaction (ORR) had high value, that is, 0.9 V vs. RHE (reversible hydrogen electrode), at higher oxidation state of the TaC{sub 0.58}N{sub 0.42}. We found that the partial oxidation of TaC{sub 0.58}N{sub 0.42} was greatly useful to enhance the catalytic activity for the ORR. The volcano plot of the ionization potential vs. the E{sub ORR} suggested that there was a suitable interaction between the surface of the partially oxidized TaC{sub 0.58}N{sub 0.42} and oxygen. (orig.)

  5. Study on Dy0.45Ba0.05Sr0.5Co0.8Fe0.2O3-δ-Ce0.85Gd0.15O1.95 composite cathode material for intermediate temperature solid oxide fuel cell

    Science.gov (United States)

    Kautkar, Pranay R.; Acharya, Smita A.

    2018-05-01

    xDy0.45Ba0.05Sr0.5Co0.8Fe0.2O3-δ - xCe0.85Gd0.15O1.95 (x = 50 %) composite cathode supported on Ce0.85Gd0.15O1.95 (GDC15) electrolyte are studied for applications in IT-SOFCs. Results attribute that Dy0.45Ba0.05Sr0.5Co0.8Fe0.2O3-δ material is chemically compatible with Ce0.85Gd0.15O1.95 (GDC15). Rietveld refined X-ray diffraction patterns notify orthorhombic (space group:Pbnm) symmetry for Dy0.45 Ba0.05Sr0.5Co0.8Fe0.2O3-δ and fluorite type structure (space group: Fm-3m) symmetry for GDC15. The polarization resistance (Rp) of composite cathode reduces to the minimum value of 1.35 Ω cm2 at 650 °C in air. Area specific resistance (ASR) of composite cathode has found 0.67 Ω.cm2 at 650°C respectively. Result shows that the surface diffusion of the dissociative adsorbed oxygen at electrode/electrolyte interface on the composite cathode.

  6. Nanostructuring the electronic conducting La0.8Sr0.2MnO3-δ cathode for high-performance in proton-conducting solid oxide fuel cells below 600°C

    KAUST Repository

    Da’ as, Eman Husni; Bi, Lei; Boulfrad, Samir; Traversa, Enrico

    2017-01-01

    Proton-conducting oxides offer a promising electrolyte solution for intermediate temperature solid oxide fuel cells (SOFCs) due to their high conductivity and low activation energy. However, the lower operation temperature leads to a reduced cathode activity and thus a poorer fuel cell performance. La0.8Sr0.2MnO3-δ (LSM) is the classical cathode material for high-temperature SOFCs, which lack features as a proper SOFC cathode material at intermediate temperatures. Despite this, we here successfully couple nanostructured LSM cathode with proton-conducting electrolytes to operate below 600°C with desirable SOFC performance. Inkjet printing allows depositing nanostructured particles of LSM on Y-doped BaZrO3(BZY) backbones as cathodes for proton-conducting SOFCs, which provides one of the highest power output for the BZY-based fuel cells below 600°C. This somehow changes the common knowledge that LSM can be applied as a SOFC cathode materials only at high temperatures (above 700°C).

  7. Nanostructuring the electronic conducting La0.8Sr0.2MnO3-δ cathode for high-performance in proton-conducting solid oxide fuel cells below 600°C

    KAUST Repository

    Da’as, Eman Husni

    2017-10-28

    Proton-conducting oxides offer a promising electrolyte solution for intermediate temperature solid oxide fuel cells (SOFCs) due to their high conductivity and low activation energy. However, the lower operation temperature leads to a reduced cathode activity and thus a poorer fuel cell performance. La0.8Sr0.2MnO3-δ (LSM) is the classical cathode material for high-temperature SOFCs, which lack features as a proper SOFC cathode material at intermediate temperatures. Despite this, we here successfully couple nanostructured LSM cathode with proton-conducting electrolytes to operate below 600°C with desirable SOFC performance. Inkjet printing allows depositing nanostructured particles of LSM on Y-doped BaZrO3(BZY) backbones as cathodes for proton-conducting SOFCs, which provides one of the highest power output for the BZY-based fuel cells below 600°C. This somehow changes the common knowledge that LSM can be applied as a SOFC cathode materials only at high temperatures (above 700°C).

  8. Development and testing of anode-supported solid oxide fuel cells with slurry-coated electrolyte and cathode

    Energy Technology Data Exchange (ETDEWEB)

    Muccillo, R.; Muccillo, E.N.S.; Fonseca, F.C.; Franca, Y.V.; Porfirio, T.C. [Centro de Ciencia e Tecnologia de Materiais, Instituto de Pesquisas Energeticas e Nucleares, C.P. 11049, Pinheiros, S. Paulo, SP 05422-970 (Brazil); de Florio, D.Z. [Instituto de Quimica, UNESP, R. Prof. Francisco Degni s/n, Araraquara, SP 14801-970 (Brazil); Berton, M.A.C.; Garcia, C.M. [Instituto de Tecnologia para o Desenvolvimento, DPMA, C.P. 19067, Curitiba, PR 81531-980 (Brazil)

    2006-06-01

    A laboratory setup was designed and put into operation for the development of solid oxide fuel cells (SOFCs). The whole project consisted of the preparation of the component materials: anode, cathode and electrolyte, and the buildup of a hydrogen leaking-free sample chamber with platinum leads and current collectors for measuring the electrochemical properties of single SOFCs. Several anode-supported single SOFCs of the type (ZrO{sub 2}:Y{sub 2}O{sub 3}+NiO) thick anode/(ZrO{sub 2}:Y{sub 2}O{sub 3}) thin electrolyte/(La{sub 0.65}Sr{sub 0.35}MnO{sub 3}+ZrO{sub 2}:Y{sub 2}O{sub 3}) thin cathode have been prepared and tested at 700 and 800{sup o}C after in situ H{sub 2} anode reduction. The main results show that the slurry-coating method resulted in single-cells with good reproducibility and reasonable performance, suggesting that this method can be considered for fabrication of SOFCs. (author)

  9. Effects of grain boundaries at the electrolyte/cathode interfaces on oxygen reduction reaction kinetics of solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Min Gi; Koo, Ja Yang; Ahn, Min Woo; Lee, Won Young [Dept. of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of)

    2017-04-15

    We systematically investigated the effects of grain boundaries (GBs) at the electrolyte/cathode interface of two conventional electrolyte materials, i.e., yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC). We deposited additional layers by pulsed laser deposition to control the GB density on top of the polycrystalline substrates, obtaining significant improvements in peak power density (two-fold for YSZ and three-fold for GDC). The enhanced performance at high GB density in the additional layer could be ascribed to the accumulation of oxygen vacancies, which are known to be more active sites for oxygen reduction reactions (ORR) than grain cores. GDC exhibited a higher enhancement than YSZ, due to the easier formation, and thus higher concentration, of oxygen vacancies for ORR. The strong relation between the concentration of oxygen vacancies and the surface exchange characteristics substantiated the role of GBs at electrolyte/cathode interfaces on ORR kinetics, providing new design parameters for highly performing solid oxide fuel cells.

  10. Investigation and optimisation of a plasma cathode electron beam gun for material processing applications

    OpenAIRE

    Del Pozo Rodriguez, Sofia

    2016-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University London. This thesis describes design, development and testing work on a plasma cathode electron beam gun as well as plasma diagnosis experiments and Electron Beam (EB) current measurements carried out with the aim of maximising the power of the EB extracted and optimising the electron beam gun system for material processing applications. The elements which influence EB gun design are described...

  11. Effects of cathode pulse at low frequency on the structure and composition of plasma electrolytic oxidation ceramic coatings

    International Nuclear Information System (INIS)

    Yao Zhongping; Xu Yongjun; Jiang Zhaohua; Wang Fuping

    2009-01-01

    The aim of this work is to investigate the effects of the cathode pulse under the low working frequency on the structure and the composition of the ceramic coatings on Ti-6Al-4V alloys by plasma electrolytic oxidation (PEO). Ceramic coatings were prepared on Ti alloy by pulsed bi-polar plasma electrolytic oxidation in NaAlO 2 solution. The phase composition, morphology, and element distribution in the coating were investigated by X-ray diffractometry, scanning electron microscopy, and energy distribution spectroscopy. The coating was mainly composed of a large amount of Al 2 TiO 5 and a little α-Al 2 O 3 and rutile TiO 2 . Increasing the cathode pulse, the amount of rutile TiO 2 was increased while the amount of Al 2 O 3 was decreased; and decreasing the cathode pulse, the amount of Al 2 O 3 was increased while the amount of rutile TiO 2 was decreased. The thickness of the coatings was increased and then decreased with the increase of the cathode pulse. The grain sizes of Al 2 TiO 5 were increased with the cathode current densities, but changed little with the cathode pulse width. The grain size of α-Al 2 O 3 was decreased with the decrease of the cathode pulse, while the grain size of TiO 2 was increased with the increase of the cathode pulse. The proper cathode pulse was helpful to reduce the roughness and to increase the density of the coatings.

  12. Sulfur-carbon nanocomposites and their application as cathode materials in lithium-sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chengdu; Dudney, Nancy J.; Howe, Jane Y.

    2017-08-01

    The invention is directed in a first aspect to a sulfur-carbon composite material comprising: (i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and (ii) elemental sulfur contained in at least a portion of said micropores. The invention is also directed to the aforesaid sulfur-carbon composite as a layer on a current collector material; a lithium ion battery containing the sulfur-carbon composite in a cathode therein; as well as a method for preparing the sulfur-composite material.

  13. Comparison of Nonprecious Metal Cathode Materials for Methane Production by Electromethanogenesis.

    KAUST Repository

    Siegert, Michael

    2014-02-18

    In methanogenic microbial electrolysis cells (MMCs), CO2 is reduced to methane using a methanogenic biofilm on the cathode by either direct electron transfer or evolved hydrogen. To optimize methane generation, we examined several cathode materials: plain graphite blocks, graphite blocks coated with carbon black or carbon black containing metals (platinum, stainless steel or nickel) or insoluble minerals (ferrihydrite, magnetite, iron sulfide, or molybdenum disulfide), and carbon fiber brushes. Assuming a stoichiometric ratio of hydrogen (abiotic):methane (biotic) of 4:1, methane production with platinum could be explained solely by hydrogen production. For most other materials, however, abiotic hydrogen production rates were insufficient to explain methane production. At -600 mV, platinum on carbon black had the highest abiotic hydrogen gas formation rate (1600 ± 200 nmol cm(-3) d(-1)) and the highest biotic methane production rate (250 ± 90 nmol cm(-3) d(-1)). At -550 mV, plain graphite (76 nmol cm(-3) d(-1)) performed similarly to platinum (73 nmol cm(-3) d(-1)). Coulombic recoveries, based on the measured current and evolved gas, were initially greater than 100% for all materials except platinum, suggesting that cathodic corrosion also contributed to electromethanogenic gas production.

  14. Preparation and electrochemical performance of sulfur-alumina cathode material for lithium-sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Kang [Faculty of Material Science and Chemistry, China University of Geosciences, 388 Lumo Road, 430074 Wuhan (China); Wang, Shengping, E-mail: spwang@cug.edu.cn [Faculty of Material Science and Chemistry, China University of Geosciences, 388 Lumo Road, 430074 Wuhan (China); Zhang, Hanyu; Wu, Jinping [Faculty of Material Science and Chemistry, China University of Geosciences, 388 Lumo Road, 430074 Wuhan (China)

    2013-06-01

    Highlights: ► Micron-sized alumina was synthesized as adsorbent for lithium-sulfur batteries. ► Sulfur-alumina material was synthesized via crystallizing nucleation. ► The Al{sub 2}O{sub 3} can provide surface area for the deposition of Li{sub 2}S and Li{sub 2}S{sub 2}. ► The discharge capacity of the battery is improved during the first several cycles. - Abstract: Nano-sized sulfur particles exhibiting good adhesion with conducting acetylene black and alumina composite materials were synthesized by means of an evaporated solvent and a concentrated crystallization method for use as the cathodes of lithium-sulfur batteries. The composites were characterized and examined by X-ray diffraction, environmental scanning electron microscopy and electrochemical methods, such as cyclic voltammetry, electrical impedance spectroscopy and charge–discharge tests. Micron-sized flaky alumina was employed as an adsorbent for the cathode material. The initial discharge capacity of the cathode with the added alumina was 1171 mAh g{sup −1}, and the remaining capacity was 585 mAh g{sup −1} after 50 cycles at 0.25 mA cm{sup −2}. Compared with bare sulfur electrodes, the electrodes containing alumina showed an obviously superior cycle performance, confirming that alumina can contribute to reducing the dissolution of polysulfides into electrolytes during the sulfur charge–discharge process.

  15. Theoretical evaluation of high-energy lithium metal phosphate cathode materials in Li-ion batteries

    Science.gov (United States)

    Howard, Wilmont F.; Spotnitz, Robert M.

    Lithium metal phosphates (olivines) are emerging as long-lived, safe cathode materials in Li-ion batteries. Nano-LiFePO 4 already appears in high-power applications, and LiMnPO 4 development is underway. Current and emerging Fe- and Mn-based intercalants, however, are low-energy producers compared to Ni and Co compounds. LiNiPO 4, a high voltage olivine, has the potential for superior energy output (>10.7 Wh in 18650 batteries), compared with commercial Li(Co,Ni)O 2 derivatives (up to 9.9 Wh). Speculative Co and Ni olivine cathode materials charged to above 4.5 V will require significant advances in electrolyte compositions and nanotechnology before commercialization. The major drivers toward 5 V battery chemistries are the inherent abuse tolerance of phosphates and the economic benefit of LiNiPO 4: it can produce 34% greater energy per dollar of cell material cost than LiAl 0.05Co 0.15Ni 0.8O 2, today's "standard" cathode intercalant in Li-ion batteries.

  16. Preparation and electrochemical performance of sulfur-alumina cathode material for lithium-sulfur batteries

    International Nuclear Information System (INIS)

    Dong, Kang; Wang, Shengping; Zhang, Hanyu; Wu, Jinping

    2013-01-01

    Highlights: ► Micron-sized alumina was synthesized as adsorbent for lithium-sulfur batteries. ► Sulfur-alumina material was synthesized via crystallizing nucleation. ► The Al 2 O 3 can provide surface area for the deposition of Li 2 S and Li 2 S 2 . ► The discharge capacity of the battery is improved during the first several cycles. - Abstract: Nano-sized sulfur particles exhibiting good adhesion with conducting acetylene black and alumina composite materials were synthesized by means of an evaporated solvent and a concentrated crystallization method for use as the cathodes of lithium-sulfur batteries. The composites were characterized and examined by X-ray diffraction, environmental scanning electron microscopy and electrochemical methods, such as cyclic voltammetry, electrical impedance spectroscopy and charge–discharge tests. Micron-sized flaky alumina was employed as an adsorbent for the cathode material. The initial discharge capacity of the cathode with the added alumina was 1171 mAh g −1 , and the remaining capacity was 585 mAh g −1 after 50 cycles at 0.25 mA cm −2 . Compared with bare sulfur electrodes, the electrodes containing alumina showed an obviously superior cycle performance, confirming that alumina can contribute to reducing the dissolution of polysulfides into electrolytes during the sulfur charge–discharge process

  17. Ti substrate coated with composite Cr–MoO2 coatings as highly selective cathode materials in hypochlorite production

    International Nuclear Information System (INIS)

    Lačnjevac, U.Č.; Jović, B.M.; Gajić-Krstajić, Lj.M.; Kovač, J.; Jović, V.D.; Krstajić, N.V.

    2013-01-01

    Highlights: ► Composite Cr–MoO 2 coatings were prepared by electrodeposition onto mild steel and Ti substrates. ► Ti/Cr–MoO 2 electrodes were investigated as cathode materials for the hypochlorite production. ► Selectivity of electrodes increased with the increase of the content of MoO 2 in the coating. ► The current efficiency for the HER exceeded 97% at the best cathode. ► The suppression of hypochlorite reduction is caused by the presence of Cr 2 O 3 at the surface. -- Abstract: The aim of this work was to investigate the possibility of preparation of the composite Cr–MoO 2 coatings onto steel and titanium substrates as cathode materials with high selective properties which imply the suppression of hypochlorite reduction as a side reaction during hypochlorite commercial production. The electrodes were prepared by simultaneous deposition of chromium and suspended MoO 2 particles on titanium substrate from acid chromium (VI) bath. The current efficiency for electrodeposition of the composite coatings did not vary significantly with the concentration of suspended MoO 2 particles. The content of molybdenum in the deposits was relatively low (0.2–1.5 at.%) and increased with increasing the concentration of suspended MoO 2 particles in the bath, in the range from 0 to 10 g dm −3 . With further increase in the concentration of MoO 2 , the content of molybdenum in the coating varied insignificantly. X-ray photoelectron spectroscopy-XPS and EDS analysis were applied to analyze elemental composition and chemical bonding of elements on the surface and in the sub-surface region of obtained coatings. When the concentration of MoO 2 particles in the bath was raised above 5 g dm −3 , the appearance of the coating changed from the typical pure chromium deposit to needle-like deposit with the appearance of black inclusions on the surface. XPS analysis and corresponding Cr 2p spectra showed the presence of chromium oxide, probably Cr 2 O 3 with Cr(3

  18. LaCoO3: Promising cathode material for protonic ceramic fuel cells based on a BaCe0.2Zr0.7Y0.1O3−δ electrolyte

    DEFF Research Database (Denmark)

    Ricote, Sandrine; Bonanos, Nikolaos; Lenrick, Filip

    2012-01-01

    Symmetric cells (cathode/electrolyte/cathode) were prepared using BaCe0.2Zr0.7Y0.1O3−δ (BCZY27) as proton conducting electrolyte and LaCoO3 (LC) infiltrated into a porous BCZY27 backbone as cathode. Single phased LC was formed after annealing in air at 600 °C for 2 h. Scanning electron micrograph...... that the presence of oxide ion conduction in the cathode material is not necessary for good performance.......Symmetric cells (cathode/electrolyte/cathode) were prepared using BaCe0.2Zr0.7Y0.1O3−δ (BCZY27) as proton conducting electrolyte and LaCoO3 (LC) infiltrated into a porous BCZY27 backbone as cathode. Single phased LC was formed after annealing in air at 600 °C for 2 h. Scanning electron micrographs...... showed the presence of the infiltrated LC in the full cathode depth. Transmission electron micrographs revealed LC grains (60–80 nm) covering partly the BCZY27 grains (200 nm–1 μm). Impedance spectra were recorded at 500 °C and 600 °C, varying the oxygen partial pressure and the water vapour pressure...

  19. Reaction mechanism and thermal stability study on cathode materials for rechargeable lithium ion batteries

    Science.gov (United States)

    Fang, Jin

    Olivine-type lithium iron phosphate has been a very promising cathode material since it was proposed by Padhi in 1997, low-cost, environmental friendly and stable structure ensure the commercialization of LiFePO 4. In LiFePO4, during charge and discharge process, Li ions are transferred between two phases, Li-poor LialphaFePO 4 and Li-rich Li1-betaFePO4, which implies a significant energy barrier for the new phase nucleation and interface growth, contrary to the fast reaction kinetics experimentally observed. The understanding of the lithiation and delithiation mechanism of this material has spurred a lot of research interests. Many theory models have been proposed to explain the reaction mechanism of LiFePO4, among them, the single phase model claims that the reaction goes through a metastable single phase, and the over potential required to form this single phase is about 30mV, so we studied the driving force to transport lithium ions between Lialpha FePO4 and Li1-betaFePO4 phases and compared the particle sizes effect. Experiment results shows that, the nano-sized (30nm) LiFePO4 has wider solid solution range, lower solid solution formation temperature and faster kinetics than normal LiFePO4 (150nm). Also a 20mV over potential was observed in both samples, either after relaxing the FePO4/LiFePO4 system to equilibrium or transport lithium from one side to the other side, the experiment result is corresponding to theoretical calculation; indicates the reaction might go through single-phase reaction mechanism. The energy and power density of lithium ion battery largely depend on cathode materials. Mn substituted LiFePO4 has a higher voltage than LiFePO4, which results a higher theoretical energy density. Safety issue is one of the most important criterions for batteries, since cathode materials need to maintain stable structure during hundreds of charge and discharge cycles and ranges of application conditions. We have reported that iron-rich compound o-Fe1-yMnyPO4

  20. Investigation of the removing process of cathode material in micro-EDM using an atomistic-continuum model

    International Nuclear Information System (INIS)

    Guo, Jianwen; Zhang, Guojun; Huang, Yu; Ming, Wuyi; Liu, Min; Huang, Hao

    2014-01-01

    Highlights: • An atomistic-continuum computational simulation model for single-discharge micro-EDM process of Cu cathode is constructed. • Cathode material is removed mainly in the form of single atoms or small clusters in micro-EDM. • Electric action leads to the formation of peaks on the surface of crater. • Removing process of cathode material under the hybrid action combining the thermal action and the electric action is studied, and the strength of either action needed for material to remove is much reduced. - Abstract: In micro-electrical discharge machining (micro-EDM), the discharge duration is ultra-short, and both the electric action and the thermal action by the discharge channel play important roles in the removing process of cathode material. However, in most researches on the machining mechanism of micro-EDM, only the thermal action is concerned. In this article, a combined atomistic-continuum modeling method in which the two-temperature model and the molecular dynamics simulation model are integrated is used to construct the simulation model for cathode in single-discharge micro-EDM process. With this simulation model, removing processes of Cu cathode material in micro-EDM under pure thermal action, pure electric action and the combination of them are investigated in a simulative way. By analyzing evolutions of temperature, stress and micro-structure of material as well as the dynamical behaviors of material in the removing process, mechanisms of the cathode material removal and crater formation are revealed. In addition, the removing process of cathode material under the combination of pure thermal action and pure electric action is compared with those under the two pure actions respectively to analyze the interactive effect between the thermal action and the electric action

  1. Electrochemical characterization of nano-sized Pd-based catalysts as cathode materials in direct methanol fuel cells.

    Science.gov (United States)

    Choi, M; Han, C; Kim, I T; An, J C; Lee, J J; Lee, H K; Shim, J

    2011-01-01

    To improve the catalytic activity of palladium (Pd) as a cathode catalyst in direct methanol fuel cells (DMFCs), we prepared palladium-titanium oxide (Pd-TiO2) catalysts which the Pd and TiO2 nanoparticles were simultaneously impregnated on carbon. We selected Pd and TiO2 as catalytic materials because of their electrochemical stability in acid solution. The crystal structure and the loading amount of Pd and TiO2 on carbon were characterized by X-ray diffraction (XRD) and energy dispersive X-ray microanalysis (EDX). The electrochemical characterization of Pd-TiO2/C catalysts for the oxygen reduction reaction was carried out in half and single cell systems. The catalytic activities of the Pd-TiO2 catalysts were strongly influenced by the TiO2 content. In the single cell test, the Pd-TiO2 catalysts showed very comparable performance to the Pt catalyst.

  2. Stabilizing nanostructured solid oxide fuel cell cathode with atomic layer deposition.

    Science.gov (United States)

    Gong, Yunhui; Palacio, Diego; Song, Xueyan; Patel, Rajankumar L; Liang, Xinhua; Zhao, Xuan; Goodenough, John B; Huang, Kevin

    2013-09-11

    We demonstrate that the highly active but unstable nanostructured intermediate-temperature solid oxide fuel cell cathode, La0.6Sr0.4CoO3-δ (LSCo), can retain its high oxygen reduction reaction (ORR) activity with exceptional stability for 4000 h at 700 °C by overcoating its surfaces with a conformal layer of nanoscale ZrO2 films through atomic layer deposition (ALD). The benefits from the presence of the nanoscale ALD-ZrO2 overcoats are remarkable: a factor of 19 and 18 reduction in polarization area-specific resistance and degradation rate over the pristine sample, respectively. The unique multifunctionality of the ALD-derived nanoscaled ZrO2 overcoats, that is, possessing porosity for O2 access to LSCo, conducting both electrons and oxide-ions, confining thermal growth of LSCo nanoparticles, and suppressing surface Sr-segregation is deemed the key enabler for the observed stable and active nanostructured cathode.

  3. Inkjet-Printed Porous Silver Thin Film as a Cathode for a Low-Temperature Solid Oxide Fuel Cell.

    Science.gov (United States)

    Yu, Chen-Chiang; Baek, Jong Dae; Su, Chun-Hao; Fan, Liangdong; Wei, Jun; Liao, Ying-Chih; Su, Pei-Chen

    2016-04-27

    In this work we report a porous silver thin film cathode that was fabricated by a simple inkjet printing process for low-temperature solid oxide fuel cell applications. The electrochemical performance of the inkjet-printed silver cathode was studied at 300-450 °C and was compared with that of silver cathodes that were fabricated by the typical sputtering method. Inkjet-printed silver cathodes showed lower electrochemical impedance due to their porous structure, which facilitated oxygen gaseous diffusion and oxygen surface adsorption-dissociation reactions. A typical sputtered nanoporous silver cathode became essentially dense after the operation and showed high impedance due to a lack of oxygen supply. The results of long-term fuel cell operation show that the cell with an inkjet-printed cathode had a more stable current output for more than 45 h at 400 °C. A porous silver cathode is required for high fuel cell performance, and the simple inkjet printing technique offers an alternative method of fabrication for such a desirable porous structure with the required thermal-morphological stability.

  4. Innovative application of ionic liquid to separate Al and cathode materials from spent high-power lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Xianlai; Li, Jinhui, E-mail: jinhui@tsinghua.edu.cn

    2014-04-01

    Highlights: • Manual dismantling is superior in spent high-power LiBs recycling. • Heated ionic liquid can effectively separate Al and cathode materials. • Fourier’s law was adopted to determine the heat transfer mechanism. • The process of spent LiBs recycling with heated ionic liquid dismantling was proposed. - Abstract: Because of the increasing number of electric vehicles, there is an urgent need for effective recycling technologies to recapture the significant amount of valuable metals contained in spent lithium-ion batteries (LiBs). Previous studies have indicated, however, that Al and cathode materials were quite difficult to separate due to the strong binding force supplied by the polyvinylidene fluoride (PVDF), which was employed to bind cathode materials and Al foil. This research devoted to seek a new method of melting the PVDF binder with heated ionic liquid (IL) to separate Al foil and cathode materials from the spent high-power LiBs. Theoretical analysis based on Fourier’s law was adopted to determine the heat transfer mechanism of cathode material and to examine the relationship between heating temperature and retention time. All the experimental and theoretic results show that peel-off rate of cathode materials from Al foil could reach 99% when major process parameters were controlled at 180 °C heating temperature, 300 rpm agitator rotation, and 25 min retention time. The results further imply that the application of IL for recycling Al foil and cathode materials from spent high-power LiBs is highly efficient, regardless of the application source of the LiBs or the types of cathode material. This study endeavors to make a contribution to an environmentally sound and economically viable solution to the challenge of spent LiB recycling.

  5. Study of Poly (3,4-ethylenedioxythiophene)/MnO2 as Composite Cathode Materials for Aluminum-Air Battery

    International Nuclear Information System (INIS)

    Kuo, Yu-Lin; Wu, Ching-Chen; Chang, Wen-Sheng; Yang, Ching-Ru; Chou, Hung-Lung

    2015-01-01

    Highlights: • Open-tunnel structure of MnO 2 catalysts were prepared by the hydrothermal method. • PEDOT was deposited on MnO 2 /carbon paper by oxidative chemical vapor deposition. • PEDOT/α-MnO 2 /10AA composite cathode shows the highest discharge performance. • The enhancement on discharge performance was due to the clear charge transfer. - Abstract: This study focuses on the development of the composite electrode materials for an aluminum-air battery and improving the oxygen reduction reaction (ORR) of the air electrode by matching alpha- and beta- manganese dioxide (MnO 2 ) with poly-(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer. The catalyst powders of α-MnO 2 and β-MnO 2 are prepared by hydrothermal method with different precursors, while PEDOT conducting polymer is subsequently deposited on the screen-printed electrodes (MnO 2 /carbon paper) by oxidative chemical vapor deposition (oCVD). Material characteristics of prepared MnO 2 powder and PEDOT layer are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman scattering spectroscopy. The half-cell polarization curve test is found to be strongly depended on the crystalline phases of MnO 2 . From experimental observations and a density functional theory (DFT) study, the conductivity of PEDOT/α-MnO 2 is found to be higher than PEDOT/β-MnO 2 contributed to structural effect mediated improvements in charge transfer. As a result, integrating the deposition of PEDOT on α-MnO 2 /carbon paper as composite cathode is suitable for the use in aluminum-air battery

  6. One-dimensional manganese-cobalt oxide nanofibres as bi-functional cathode catalysts for rechargeable metal-air batteries

    OpenAIRE

    Jung, Kyu-Nam; Hwang, Soo Min; Park, Min-Sik; Kim, Ki Jae; Kim, Jae-Geun; Dou, Shi Xue; Kim, Jung Ho; Lee, Jong-Won

    2015-01-01

    Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanof...

  7. Ab initio Defect Energetics in LaBO3 Perovskite Solid Oxide Fuel Cell Materials

    DEFF Research Database (Denmark)

    Lee, Yueh-Lin; Morgan, Dane; Kleis, Jesper

    2009-01-01

    Perovskite materials of the form ABO3 are a promising family of compounds for use in solid oxide fuel cell (SOFC) cathodes. Study of the physics of these compounds under SOFC conditions with ab initio methods is particularly challenging due to high temperatures, exchange of oxygen with O2 gas...

  8. Magnetron sputtered zinc oxide nanorods as thickness-insensitive cathode interlayer for perovskite planar-heterojunction solar cells.

    Science.gov (United States)

    Liang, Lusheng; Huang, Zhifeng; Cai, Longhua; Chen, Weizhong; Wang, Baozeng; Chen, Kaiwu; Bai, Hua; Tian, Qingyong; Fan, Bin

    2014-12-10

    Suitable electrode interfacial layers are essential to the high performance of perovskite planar heterojunction solar cells. In this letter, we report magnetron sputtered zinc oxide (ZnO) film as the cathode interlayer for methylammonium lead iodide (CH3NH3PbI3) perovskite solar cell. Scanning electron microscopy and X-ray diffraction analysis demonstrate that the sputtered ZnO films consist of c-axis aligned nanorods. The solar cells based on this ZnO cathode interlayer showed high short circuit current and power conversion efficiency. Besides, the performance of the device is insensitive to the thickness of ZnO cathode interlayer. Considering the high reliability and maturity of sputtering technique both in lab and industry, we believe that the sputtered ZnO films are promising cathode interlayers for perovskite solar cells, especially in large-scale production.

  9. New polyanion-based cathode materials for alkali-ion batteries

    Science.gov (United States)

    Yaghoobnejad Asl, Hooman

    A number of new materials have been discovered through exploratory synthesis with the aim to be studied as the positive electrode (cathode) in Li-ion and Na-ion batteries. The focus has been set on the ease of synthesis, cost and availability of active ingredients in the battery, and decent cycle-life performance through a combination of iron and several polyanionic ligands. An emphasis has been placed also on phosphite (HPO32-) as a polyanionic ligand, mainly due to the fact that it has not been studied seriously before as a polyanion for cathode materials. The concept of mixed polyanions, for example, boro-phosphate and phosphate-nitrates were also explored. In each case the material was first made and purified via different synthetic strategies, and the crystal structure, which dominantly controls the performance of the materials, has been extensively studied through Single-Crystal X-ray Diffraction (SCXRD) or synchrotron-based Powder X-ray Diffraction (PXRD). This investigation yielded four new compositions, namely Li3Fe 2(HPO3)3Cl, LiFe(HPO3)2, Li0.8Fe(H2O)2B[P2O8]•H 2O and AFePO4NO3 (A = NH4/Li, K). Furthermore, for each material the electrochemical performance for insertion of Li+ ion has been studied by means of various electrochemical techniques to reveal the nature of alkali ion insertion. In addition Na-ion intercalation has been studied for boro-phosphate and AFePO4NO3. Additionally a novel synthesis procedure has been reported for tavorite LiFePO4F 1-x(OH)x, where 0 ≤ x ≤ 1, an important class of cathode materials. The results obtained clearly demonstrate the importance of crystal structure on the cathode performance through structural and compositional effects. Moreover these findings may contribute to the energy storage community by providing insight into the solid-state science of electrode material synthesis and proposing new alternative compositions based on sustainable materials.

  10. A novel cobalt-free layered GdBaFe{sub 2}O{sub 5+{delta}} cathode for proton conducting solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Hanping; Xue, Xingjian [Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2010-07-01

    While cobalt-containing perovskite-type cathode materials facilitate the activation of oxygen reduction, they also suffer from problems like poor chemical stability in CO{sub 2} and high thermal expansion coefficients. In this research, a cobalt-free layered GdBaFe{sub 2}O{sub 5+{delta}} (GBF) perovskite was developed as a cathode material for protonic ceramic membrane fuel cells (PCMFCs) based on proton conducting electrolyte of stable BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{delta}} (BZCY7). The button cells of Ni-BZCY7 vertical stroke BZCY7 vertical stroke GBF were fabricated and characterized using complex impedance technique from 600 to 700 C. An open-circuit potential of 1.007 V, maximum power density of 417 mW cm{sup -2}, and a low electrode polarization resistance of 0.18 {omega} cm{sup 2} were achieved at 700 C. The results indicate that layered GBF perovskite is a good candidate for cobalt-free cathode material, while the developed Ni-BZCY7 vertical stroke BZCY7 vertical stroke GBF cell is a promising functional material system for solid oxide fuel cells. (author)

  11. Tuning Li2MO3 phase abundance and suppressing migration of transition metal ions to improve the overall performance of Li- and Mn-rich layered oxide cathode

    Science.gov (United States)

    Zhang, Shiming; Tang, Tian; Ma, Zhihua; Gu, Haitao; Du, Wubing; Gao, Mingxia; Liu, Yongfeng; Jian, Dechao; Pan, Hongge

    2018-03-01

    The poor cycling stability of Li- and Mn-rich layered oxide cathodes used in lithium-ion batteries (LIBs) has severely limited their practical application. Unfortunately, current strategies to improve their lifecycle sacrifice initial capacity. In this paper, we firstly report the synergistic improvement of the electrochemical performance of a Li1.2Ni0.13Co0.13Mn0.54O2 (LNCMO) cathode material, including gains for capacity, cycling stability, and rate capability, by the partial substitution of Li+ ions by Mg2+ ions. Electrochemical performance is evaluated by a galvanostatic charge and discharge test and electrochemical impedance spectroscopy (EIS). Structure and morphology are characterized by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Compared with the substitution of transition metal (TM) ions with Mg2+ ions reported previously, the substitution of Li+ ions by Mg2+ ions not only drastically ameliorates the capacity retention and rate performance challenges of LNCMO cathodes but also markedly suppresses their voltage fading, due to the inhibition of the migration of TM ions during cycling, while also increasing the capacity of the cathode due to an increased abundance of the Li2MO3 phase.

  12. X-ray Diffraction Studies of the Structure and Thermochemistry of Alkaline-Earth Oxide-Coated Thermionic Cathodes

    Science.gov (United States)

    Karikari, E. K.; Bassey, E.; Wintucky, Edwin G.

    1998-01-01

    NASA LeRC has a broad, active cathode technology development program in which both experimental and theoretical studies are being employed to further development of thermionic cathodes for use as electron sources in vacuum devices for communications and other space applications. One important type of thermionic cathode under development is the alkaline-earth oxide-coated (BaO, SrO, CaO) cathode. Significant improvements in the emission characteristics of this cathode have been obtained through modification of the chemical composition and morphology of the oxide coating, with the best result thus far coming from the addition of In2O3 and Sc2O3. Whereas the In2O3 produces a finer, more uniform particle structure, the exact chemical state and role of the Sc2O3 in the emission enhancement is unknown. The purpose of this cooperative agreement is to combine the studies of the surface chemistry and electron emission at NASA LeRC of chemically modified oxide coatings with a study of the thermochemistry and crystal structure using X-ray diffraction equipment and expertise at Clark Atlanta University (CAU). The study at CAU is intended to provide the description and understanding of the structure and thermochemistry needed for further improvement and optimization of the modified coatings. A description of the experimental procedure, preliminary X-ray diffraction test results, together with the design of an ultrahigh vacuum chamber necessary for high temperature thermochemistry studies will be presented.

  13. Preparation of cathode materials for Li-ion cells by acid dissolution

    International Nuclear Information System (INIS)

    Oh, Si Hyoung; Jeong, Woon Tae; Cho, Won Il; Cho, Byung Won; Woo, Kyoungja

    2005-01-01

    New synthesis route called acid dissolution method, preparing the high-performance cathode materials for the lithium-ion cells, was successfully developed. In this method, insoluble starting materials such as metal carbonates or metal hydroxides are dissolved in strong organic acidic solution which contains a chelating agent. And then, the solvent of the solution containing starting materials is eliminated to obtain the xerogel of the initial solution whose chemical form is expressed as Li[MA 3 ], where M is a transition metal atom and A is the anion of the organic acid. The xerogel is then calcined at the high temperature to obtain polycrystalline cathode materials. In this work, the applicability of this method was demonstrated synthesizing a polycrystalline single-phase LiCoO 2 using lithium carbonate, cobalt hydroxide as the insoluble starting materials and the acrylic acid as a chelating agent. The synthesized powders calcined at 800 deg. C showed a good electrochemical performance in the half-cell test

  14. Electrochemical behavior of uranium oxide in a LiCl-Li2O molten salt with the integrated cathode assembly

    International Nuclear Information System (INIS)

    Park, Sung Bin; Park, Byung Heung; Kang, Dae Seoung; Kwon, Seon Gil; Seo, Chung Seok; Park, Seong Won

    2005-01-01

    Electrochemical reduction of uranium oxide to uranium metal was studied in a LiCl-Li 2 O molten salt system. By means of a cyclic voltammetry and a chronopotentiometry, the electrolytic reduction of uranium oxide has been studied to establish the reduction mechanisms and the effects of the thickness of the uranium oxide on the overpotential of the cathode and anode were investigated. From the voltamograms, the reduction potentials of the uranium oxide and Li 2 O were obtained and the two mechanisms of the electrolytic reduction were considered with regards to the applied cathode potential. In the chronopotentiograms, the exchange current, the transfer coefficient and the maximum allowable current based on the Tafel behavior were obtained according to the thickness of the uranium oxide which is loaded into the porous MgO membrane. (author)

  15. Functioning mechanism of AlF3 coating on the Li- and Mn-rich cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jianming; Gu, Meng; Xiao, Jie; Polzin, Bryant; Yan, Pengfei; Chen, Xilin; Wang, Chong M.; Zhang, Jiguang

    2014-11-25

    Li- and Mn-rich (LMR) material is a very promising cathode for lithium ion batteries because of their high theoretical energy density (~900 Wh kg-1) and low cost. However, their poor long-term cycling stability, voltage fade, and low rate capability are significant barriers hindered their practical applications. Surface coating, e.g. AlF3 coating, can significantly improve the capacity retention and enhance the rate capability. However, the fundamental mechanism of this improvement and the microstructural evolution related to the surface coating is still not well understood. Here, we report systematic studies of the microstructural changes of uncoated and AlF3-coated materials before and after cycling using aberration-corrected scanning/transmission electron microscopy and electron energy loss spectroscopy. The results reveal that surface coating can reduce the oxidation of electrolyte at high voltage, thus suppressing the accumulation of SEI layer on electrode particle surface. Surface coating also enhances structural stability of the surface region (especially the electrochemically transformed spinel-like phase), and protects the electrode from severe etching/corrosion by the acidic species in the electrolyte, therefore limiting the degradation of the material. Moreover, surface coating can alleviate the undesirable voltage fade by minimize layered-spinel phase transformation in the bulk region of the materials. These fundamental findings may also be widely applied to explain the functioning mechanism of other surface coatings used in a broad range of electrode materials.

  16. Power generation using spinel manganese-cobalt oxide as a cathode catalyst for microbial fuel cell applications.

    Science.gov (United States)

    Mahmoud, Mohamed; Gad-Allah, Tarek A; El-Khatib, K M; El-Gohary, Fatma

    2011-11-01

    This study focused on the use of spinel manganese-cobalt (Mn-Co) oxide, prepared by a solid state reaction, as a cathode catalyst to replace platinum in microbial fuel cells (MFCs) applications. Spinel Mn-Co oxides, with an Mn/Co atomic ratios of 0.5, 1, and 2, were prepared and examined in an air cathode MFCs which was fed with a molasses-laden synthetic wastewater and operated in batch mode. Among the three Mn-Co oxide cathodes and after 300 h of operation, the Mn-Co oxide catalyst with Mn/Co atomic ratio of 2 (MnCo-2) exhibited the highest power generation 113 mW/m2 at cell potential of 279 mV, which were lower than those for the Pt catalyst (148 mW/m2 and 325 mV, respectively). This study indicated that using spinel Mn-Co oxide to replace platinum as a cathodic catalyst enhances power generation, increases contaminant removal, and substantially reduces the cost of MFCs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Mechanisms of LiCoO2 Cathode Degradation by Reaction with HF and Protection by Thin Oxide Coatings.

    Science.gov (United States)

    Tebbe, Jonathon L; Holder, Aaron M; Musgrave, Charles B

    2015-11-04

    Reactions of HF with uncoated and Al and Zn oxide-coated surfaces of LiCoO2 cathodes were studied using density functional theory. Cathode degradation caused by reaction of HF with the hydroxylated (101̅4) LiCoO2 surface is dominated by formation of H2O and a LiF precipitate via a barrierless reaction that is exothermic by 1.53 eV. We present a detailed mechanism where HF reacts at the alumina coating to create a partially fluorinated alumina surface rather than forming AlF3 and H2O and thus alumina films reduce cathode degradation by scavenging HF and avoiding H2O formation. In contrast, we find that HF etches monolayer zinc oxide coatings, which thus fail to prevent capacity fading. However, thicker zinc oxide films mitigate capacity loss by reacting with HF to form a partially fluorinated zinc oxide surface. Metal oxide coatings that react with HF to form hydroxyl groups over H2O, like the alumina monolayer, will significantly reduce cathode degradation.

  18. Chemical behavior of lanthanides-tungsten composite materials used in thermo-emissive cathodes

    International Nuclear Information System (INIS)

    Cadoret, K.; Cachard, J. de; Martinez, L.; Millot, F.; Hennet, L.; Douy, A.; Licheron, M.

    2001-01-01

    This work presents the crystallography and chemistry of new lanthanides-tungsten composite materials developed to manufacture thermionic cathodes for power grid tubes, based on the same principle than thorium-free cathodes. By mean of x-Ray diffraction at high temperature and under vacuum with synchrotron radiation facilities, we followed in real time the different phases and phase transitions that can occur during the heating process and the carburization at 1550 o C of such tungstates deposits on thin tungsten ribbons. Melting points for composition between 9 La 2 O 3 - 1 WO 3 and 2 La 2 O 3 - 9 WO 3 were specified under the pressure of 1x10 -6 mbar. After interpretation of x-ray diffraction results, phase diagram of n La 2 O 3 - m WO 3 system under vacuum in equilibrium with metallic tungsten have been deduced. Moreover we underline by these works the fact that using a lanthanum-rich tungstate involves better stability and chemical homogeneity of the cathodes surfaces with temperature. (author)

  19. Nanocomposite of graphene and metal oxide materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2012-09-04

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10C.

  20. Nanocomposite of graphene and metal oxide materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2013-10-15

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10 C.

  1. Enhanced electrochemical properties of LiNiO{sub 2}-based cathode materials by nanoscale manganese carbonate treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Junkai; Wang, Zhixing, E-mail: zxwang.csu@hotmail.com; Guo, Huajun; Li, Xinhai

    2017-05-01

    Highlights: • Li residuals are consumed during the process of modification. • MnO{sub 2} coating layer can protect bulk material from the erosion of electrolyte. • The electrochemical performance is enhanced by the nanosacle MnCO{sub 3} treatment. • The enhancement of coating can be strengthened by the removal of lithium impurities. - Abstract: LiNiO{sub 2}-based layered oxides are of great importance as cathode materials for rechargeable batteries. In this paper, illustrating LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} as an example, the effect of nanoscale MnCO{sub 3} treatment on LiNiO{sub 2}-based materials is investigated for the first time. The structures of materials and the properties about the object surface are characterized by XRD, SEM, TEM, EDAX and XPS. The results demonstrate that a part of MnCO{sub 3} is able to react with lithium impurities to form nonstoichiometric Li{sub x}Mn{sub y}O{sub 4} and the rest of MnCO{sub 3} is converted to MnO{sub 2} coating on the surface of the material in situ. After 100 repeated cycles at 1C, the modified material exhibits a capacity retention rate of 91.2%, while the bare material only remains 84.8%. And the modified material exhibits more significantly improved cycling stability when cycling at 60 °C, maintaining 85.7% of its initial capacity at 1C after 100th cycles. The consumption of Li impurities can decelerate the decomposition of electrolyte during cycling, thus result in less resistive byproducts. Moreover, the obtained MnO{sub 2} coating layer acts as an isolating layer to suppress the drastic reaction between active material and electrolyte. This synergistic effect is responsible for the excellent properties of MnCO{sub 3}-modified material.

  2. High-Capacity Cathode Material with High Voltage for Li-Ion Batteries.

    Science.gov (United States)

    Shi, Ji-Lei; Xiao, Dong-Dong; Ge, Mingyuan; Yu, Xiqian; Chu, Yong; Huang, Xiaojing; Zhang, Xu-Dong; Yin, Ya-Xia; Yang, Xiao-Qing; Guo, Yu-Guo; Gu, Lin; Wan, Li-Jun

    2018-03-01

    Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy density of batteries is to search for high-capacity electrode materials. According to the concept of energy quality, a high-voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high-capacity Li-rich cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after-treatment, and the specific energy is improved from 912 to 1033 Wh kg -1 . The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Real-time imaging, spectroscopy, and structural investigation of cathodic plasma electrolytic oxidation of molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Stojadinović, Stevan, E-mail: sstevan@ff.bg.ac.rs; Tadić, Nenad; Šišović, Nikola M.; Vasilić, Rastko [Faculty of Physics, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia)

    2015-06-21

    In this paper, the results of the investigation of cathodic plasma electrolytic oxidation (CPEO) of molybdenum at 160 V in a mixed solution of borax, water, and ethylene glycol are presented. Real-time imaging and optical emission spectroscopy were used for the characterization of the CPEO. During the process, vapor envelope is formed around the cathode and strong electric field within the envelope caused the generation of plasma discharges. The spectral line shape analysis of hydrogen Balmer line H{sub β} (486.13 nm) shows that plasma discharges are characterized by the electron number density of about 1.4 × 10{sup 21 }m{sup −3}. The electron temperature of 15 000 K was estimated by measuring molybdenum atomic lines intensity. Surface morphology, chemical, and phase composition of coatings formed by CPEO were characterized by scanning electron microscopy with energy dispersive x-ray spectroscopy and x-ray diffraction. The elemental components of CPEO coatings are Mo and O and the predominant crystalline form is MoO{sub 3}.

  4. Electrochemical characterization of a LiV3O8-polypyrrole composite as a cathode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Tian Fanghua; Liu Li; Yang Zhenhua; Wang Xingyan; Chen Quanqi; Wang Xianyou

    2011-01-01

    Research highlights: → LiV 3 O 8 -PPy composite has been synthesized successfully. → LiV 3 O 8 -PPy composite shows better cycling behavior and rate capability than LiV 3 O 8 . → LiV 3 O 8 -PPy composite shows lower electrochemical resistance than LiV 3 O 8 . - Abstract: LiV 3 O 8 -Polypyrrole (LiV 3 O 8 -PPy) composite has been chemically synthesized by an oxidative polymerization of pyrrole monomer on the surface of LiV 3 O 8 using ferric chloride as oxidizing agent. The electrochemical properties of LiV 3 O 8 -PPy composite were systematically investigated using a variety of electrochemical methods. The LiV 3 O 8 -PPy composite electrode exhibited better cycling behavior and superior rate capability as compared with the bare LiV 3 O 8 electrode. Cyclic voltammetry corroborated the galvanostatic cycling tests, with the composite cathode material showing better reversibility than bare material. Finally, fitting the impedance results to an equivalent circuit indicated that the enhanced electrochemical performances of LiV 3 O 8 -PPy composite resulted from a facilitated kinetics of interfacial charge transfer in the presence of PPy.

  5. Solid oxide fuel cell power plant having a fixed contact oxidation catalyzed section of a multi-section cathode air heat exchanger

    Science.gov (United States)

    Saito, Kazuo; Lin, Yao

    2015-02-17

    The multi-section cathode air heat exchanger (102) includes at least a first heat exchanger section (104), and a fixed contact oxidation catalyzed section (126) secured adjacent each other in a stack association. Cool cathode inlet air flows through cool air channels (110) of the at least first (104) and oxidation catalyzed sections (126). Hot anode exhaust flows through hot air channels (124) of the oxidation catalyzed section (126) and is combusted therein. The combusted anode exhaust then flows through hot air channels (112) of the first section (104) of the cathode air heat exchanger (102). The cool and hot air channels (110, 112) are secured in direct heat exchange relationship with each other so that temperatures of the heat exchanger (102) do not exceed 800.degree. C. to minimize requirements for using expensive, high-temperature alloys.

  6. Effect of substrate and cathode parameters on the properties of suspension plasma sprayed solid oxide fuel cell electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Waldbillig, D.; Tang, Z.; Burgess, A. [British Columbia Univ., Vancouver, BC (Canada); Kesler, O. [Toronto Univ., ON (Canada)

    2008-07-01

    An axial injection suspension plasma spray system has been used to produce layers of fully stabilized yttriastabilized zirconia (YSZ) that could be used as solid oxide fuel cell (SOFC) electrolytes. Suspension plasma spraying is a promising technique for the rapid production of coatings with fine microstructures and controlled porosity without requiring a post-deposition heat treatment. This new manufacturing technique to produce SOFC active layers requires the build up of a number of different plasma sprayed SOFC functional layers (cathode, electrolyte and anode) sequentially on top of each other. To understand the influence of the substrate and previouslydeposited coating layers on subsequent coating layer properties, YSZ layers were deposited on top of plasma sprayed composite lanthanum strontium manganite (LSM)/YSZ cathode layers that were first deposited on porous ferritic stainless steel substrates. Three layer half cells consisting of the porous steel substrate, composite cathode, and suspension plasma sprayed electrolyte layer were then characterized. A systematic study was performed in order to investigate the effect of parameters such as substrate and cathode layer roughness, substrate surface pore size, and cathode microstructure and thickness on electrolyte deposition efficiency, cathode and electrolyte permeability, and layer microstructure. (orig.)

  7. Ab initio study of perovskite type oxide materials for solid oxide fuel cells

    Science.gov (United States)

    Lee, Yueh-Lin

    2011-12-01

    Perovskite type oxides form a family of materials of significant interest for cathodes and electrolytes of solid oxide fuel cells (SOFCs). These perovskites not only are active catalysts for surface oxygen reduction (OR) reactions but also allow incorporating the spilt oxygen monomers into their bulk, an unusual and poorly understood catalytic mechanism that couples surface and bulk properties. The OR mechanisms can be influenced strongly by defects in perovskite oxides, composition, and surface defect structures. This thesis work initiates a first step in developing a general strategy based on first-principles calculations for detailed control of oxygen vacancy content, transport rates of surface and bulk oxygen species, and surface/interfacial reaction kinetics. Ab initio density functional theory methods are used to model properties relevant for the OR reactions on SOFC cathodes. Three main research thrusts, which focus on bulk defect chemistry, surface defect structures and surface energetics, and surface catalytic properties, are carried to investigate different level of material chemistry for improved understanding of key physics/factors that govern SOFC cathode OR activity. In the study of bulk defect chemistry, an ab initio based defect model is developed for modeling defect chemistry of LaMnO 3 under SOFC conditions. The model suggests an important role for defect interactions, which are typically excluded in previous defect models. In the study of surface defect structures and surface energetics, it is shown that defect energies change dramatically (1˜2 eV lower) from bulk values near surfaces. Based on the existing bulk defect model with the calculated ab initio surface defect energetics, we predict the (001) MnO 2 surface oxygen vacancy concentration of (La0.9Sr0.1 )MnO3 is about 5˜6 order magnitude higher than that of the bulk under typical SOFC conditions. Finally, for surface catalytic properties, we show that area specific resistance, oxygen

  8. Crystallite Size and Microstrain Measurement of Cathode Material after Mechanical Milling using Neutron Diffraction Technique

    Directory of Open Access Journals (Sweden)

    A. Fajar

    2010-12-01

    Full Text Available The measurements of neutron diffraction patterns of commercially product and 10 hour mechanically milled cathode material lithium cobaltites (LiCoO2 have been performed. Rietveld analysis using FullProf does not show the change of crystal structure due to milling process, but the diffraction pattern has a lower intensity and the diffraction-line was broadening. The results of line-broadening study on milled sample using Rietveld methods detected that the microstrain was occurred in the sample with value 0.127080(35 % and the average crystallite size was 424.78(20 Å.

  9. Enhanced oxygen reduction activity and solid oxide fuel cell performance with a nanoparticles-loaded cathode.

    Science.gov (United States)

    Zhang, Xiaomin; Liu, Li; Zhao, Zhe; Tu, Baofeng; Ou, Dingrong; Cui, Daan; Wei, Xuming; Chen, Xiaobo; Cheng, Mojie

    2015-03-11

    Reluctant oxygen-reduction-reaction (ORR) activity has been a long-standing challenge limiting cell performance for solid oxide fuel cells (SOFCs) in both centralized and distributed power applications. We report here that this challenge has been tackled with coloading of (La,Sr)MnO3 (LSM) and Y2O3 stabilized zirconia (YSZ) nanoparticles within a porous YSZ framework. This design dramatically improves ORR activity, enhances fuel cell output (200-300% power improvement), and enables superior stability (no observed degradation within 500 h of operation) from 600 to 800 °C. The improved performance is attributed to the intimate contacts between nanoparticulate YSZ and LSM particles in the three-phase boundaries in the cathode.

  10. Controlled synthesis of lithium-rich layered Li1.2Mn0.56Ni0.12Co0.12O2 oxide with tunable morphology and structure as cathode material for lithium-ion batteries by solvo/hydrothermal methods

    International Nuclear Information System (INIS)

    Fu, Fang; Huang, Yiyin; Wu, Peng; Bu, Yakun; Wang, Yaobing; Yao, Jiannian

    2015-01-01

    Highlights: • Li 1.2 Mn 0.56 Ni 0.12 Co 0.12 O 2 with different shapes was successfully prepared. • The solvent plays a key role in the formation of the product with various shapes. • The sample prepared by solvothermal method exhibits higher discharge capacity. • Its reversible capacity is approximately 306.9 mA h g −1 at 0.2 C. - Abstract: A Li-rich layered cathode material Li 1.2 Mn 0.56 Ni 0.12 Co 0.12 O 2 (0.5Li 2 MnO 3 ⋅0.5Li 1.2 Mn 0.4 Ni 0.3 Co 0.3 O 2 ) with different morphologies has been successfully prepared by solvothermal and hydrothermal methods. The result demonstrates that the solvent plays a crucial role in the formation of the precursor and final product with various shapes and sizes. When tested as the cathode material for lithium ion batteries, the sample prepared by solvothermal method exhibits higher discharge capacity, better cycling performance, and more excellent rate capacity. It delivers a discharge capacity of 306.9 mA h g −1 at 0.2 C and 118.6 mA h g −1 even at a high rate of 5.0 C. The outstanding performance of the sample prepared by solvothermal method can be attributed to the well-ordered structure and well-defined morphology with smaller particle size and uniform distribution. The current study paves a new concept and applicable way to prepare high performance Li-rich layered cathode material for LIBs

  11. Li2C2, a High-Capacity Cathode Material for Lithium Ion Batteries.

    Science.gov (United States)

    Tian, Na; Gao, Yurui; Li, Yurong; Wang, Zhaoxiang; Song, Xiaoyan; Chen, Liquan

    2016-01-11

    As a typical alkaline earth metal carbide, lithium carbide (Li2C2) has the highest theoretical specific capacity (1400 mA h g(-1)) among all the reported lithium-containing cathode materials for lithium ion batteries. Herein, the feasibility of using Li2C2 as a cathode material was studied. The results show that at least half of the lithium can be extracted from Li2C2 and the reversible specific capacity reaches 700 mA h g(-1). The C≡C bond tends to rotate to form C4 (C≡C⋅⋅⋅C≡C) chains during lithium extraction, as indicated with the first-principles molecular dynamics (FPMD) simulation. The low electronic and ionic conductivity are believed to be responsible for the potential gap between charge and discharge, as is supported with density functional theory (DFT) calculations and Arrhenius fitting results. These findings illustrate the feasibility to use the alkali and alkaline earth metal carbides as high-capacity electrode materials for secondary batteries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Solid oxide fuel cell cathode infiltrate particle size control and oxygen surface exchange resistance determination

    Science.gov (United States)

    Burye, Theodore E.

    Over the past decade, nano-sized Mixed Ionic Electronic Conducting (MIEC) -- micro-sized Ionic Conducting (IC) composite cathodes produced by the infiltration method have received much attention in the literature due to their low polarization resistance (RP) at intermediate (500-700°C) operating temperatures. Small infiltrated MIEC oxide nano-particle size and low intrinsic MIEC oxygen surface exchange resistance (Rs) have been two critical factors allowing these Nano-Micro-Composite Cathodes (NMCCs) to achieve high performance and/or low temperature operation. Unfortunately, previous studies have not found a reliable method to control or reduce infiltrated nano-particle size. In addition, controversy exists on the best MIEC infiltrate composition because: 1) Rs measurements on infiltrated MIEC particles are presently unavailable in the literature, and 2) bulk and thin film Rs measurements on nominally identical MIEC compositions often vary by up to 3 orders of magnitude. Here, two processing techniques, precursor nitrate solution desiccation and ceria oxide pre-infiltration, were developed to systematically produce a reduction in the average La0.6Sr0.4Co0.8Fe 0.2O3-delta (LSCF) infiltrated nano-particle size from 50 nm to 22 nm. This particle size reduction reduced the SOFC operating temperature, (defined as the temperature where RP=0.1 Ocm 2) from 650°C to 540°C. In addition, Rs values for infiltrated MIEC particles were determined for the first time through finite element modeling calculations on 3D Focused Ion Beam-Scanning Electron Microscope (FIB-SEM) reconstructions of electrochemically characterized infiltrated electrodes.

  13. Vanadium Oxyfluoride/Few-Layer Graphene Composite as a High-Performance Cathode Material for Lithium Batteries.

    Science.gov (United States)

    Cambaz, Musa Ali; Vinayan, B P; Clemens, Oliver; Munnangi, Anji Reddy; Chakravadhanula, Venkata Sai Kiran; Kübel, Christian; Fichtner, Maximilian

    2016-04-18

    Metal oxyfluoride compounds are gathering significant interest as cathode materials for lithium ion batteries at the moment because of their high theoretical capacity and resulting high energy density. In this regard, a new and direct approach is presented to synthesize phase-pure vanadium oxyfluoride (VO2F). The structure of VO2F was identified by Rietveld refinement of the powder X-ray diffraction (XRD) pattern. It crystallizes in a perovskite-type structure with disorder of the oxide and fluoride ions. The as-synthesized VO2F was tested as a cathode material for lithium ion batteries after being surface-coated with few-layer graphene. The VO2F delivered a first discharge capacity of 254 mA h g(-1) and a reversible capacity of 208 mA h g(-1) at a rate of C/20 for the first 20 cycles with an average discharge voltage of 2.84 V, yielding an energy density of 591 W h kg(-1). Improved rate capability that outperforms the previous report has been achieved, showing a discharge capacity of 150 mA h g(-1) for 1 C. The structural changes during lithium insertion and extraction were monitored by ex-situ XRD analysis of the electrodes discharged and charged to various stages. Lithium insertion results in an irreversible structural change of the anion lattice from (3)/4 cubic close packing to hexagonal close packing to accommodate the inserted lithium ions while keeping the overall space-group symmetry. For the first time we have revealed a structural change for the ReO3-type structure of as-prepared VO2F to the RhF3 structure after lithiation/delithiation, with structural changes that have not been observed in previous reports. Furthermore, the new synthetic approach described here would be a platform for the synthesis of new oxyfluoride compounds.

  14. Enriching Metal-Oxidizing Microbes from Marine Sediment on Cathodic Currents

    Science.gov (United States)

    Rowe, A. R.; Nealson, K. H.

    2013-12-01

    The ability of organisms to transfer electrons to and from substrates outside the cell is reshaping the way we look at microbial respiration. While this process, termed extracellular electron transport (EET), has been described in a number of metal reducing organisms, current evidence suggests that this process is widespread in nature and across physiologies. Additionally, it has been speculated that these previously overlooked electrochemical interactions may play an important role in global biogeochemical cycles. Requirements for EET could play a role in why the ';uncultured majority' have so far been resistant to culturing. As such, we are currently developing culturing techniques to target microbes capable of utilizing insoluble electron acceptors utilizing electrochemical techniques. Microbe-electrode interactions are analogous to the reactions that occur between microbes and minerals and may provide an apt way to mimic the environmental conditions (i.e., insoluble electron donor/acceptor at specific redox potentials) required for culturing specialized or EET dependent metabolisms. It has been previously demonstrated that aquatic sediments are capable of utilizing anodes as electron acceptors, thereby generating a current. While, it is known that microbes utilize electrons from a cathode for the reduction of different metals and oxygen in microbial fuel cells, currently there are no reports of environmental enrichments of microbes using cathodes. Replicate microcosms from marine sediments (sampled from Catalina Harbor, California) were incubated with ITO plated glass electrodes. Negative current production at -400mV (vs. Ag/AgCl reference electrodes) potentials was sustained for four weeks. Secondary enrichments were then constructed using the cathode as the primary electron source and a variety of anaerobic terminal electron acceptors--Nitrate, Fe3+, and SO42-. Positive current was maintained in enrichment cultures (compared to abiotic control containing

  15. Transport parameters of thin, supported cathode layers in solid oxide fuel cells (SOFCs); Transportparameter duenner, getraegerter Kathodenschichten der oxidkeramischen Brennstoffzelle

    Energy Technology Data Exchange (ETDEWEB)

    Wedershoven, Christian

    2010-12-22

    The aim of this work was to determine the transport properties of thin cathode layers, which are part of the composite layer of a fabricated anode-supported solid oxide fuel cell (SOFC). The transport properties of the anode and cathode have a significant influence on the electrochemical performance of a fuel cell stack and therefore represent an important parameter when designing fuel cell stacks. In order to determine the transport parameters of the cathode layers in a fabricated SOFC, it is necessary to permeate the thin cathode layer deposited on the gas-tight electrolyte with a defined gas transport. These thin cathode layers cannot be fabricated as mechanically stable single layers and cannot therefore be investigated in the diffusion and permeation experiments usually used to determine transport parameters. The setup of these experiments - particularly the sample holder - was therefore altered in this work. The result of this altered setup was a three-dimensional flow configuration. Compared to the conventional setup, it was no longer possible to describe the gas transport in the experiments with an analytical one-dimensional solution. A numerical solution process had to be used to evaluate the measurements. The new setup permitted a sufficiently symmetrical gas distribution and thus allowed the description of the transport to be reduced to a two-dimensional description, which significantly reduced the computational effort required to evaluate the measurements. For pressure-induced transport, a parametrized coherent expression of transport could be derived. This expression is equivalent to the analytical description of the transport in conventional measurement setups, with the exception of parameters that describe the geometry of the gas diffusion. In this case, a numerical process is not necessary for the evaluation. Using the transport parameters of mechanically stable anode substrates, which can be measured both in the old and the new setups, the old and

  16. Electroactive materials for rechargeable batteries

    Science.gov (United States)

    Wu, Huiming; Amine, Khalil; Abouimrane, Ali

    2015-04-21

    An as-prepared cathode for a secondary battery, the cathode including an alkaline source material including an alkali metal oxide, an alkali metal sulfide, an alkali metal salt, or a combination of any two or more thereof.

  17. Nature of the Electrochemical Properties of Sulphur Substituted LiMn2O4 Spinel Cathode Material Studied by Electrochemical Impedance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Monika Bakierska

    2016-08-01

    Full Text Available In this work, nanostructured LiMn2O4 (LMO and LiMn2O3.99S0.01 (LMOS1 spinel cathode materials were comprehensively investigated in terms of electrochemical properties. For this purpose, electrochemical impedance spectroscopy (EIS measurements as a function of state of charge (SOC were conducted on a representative charge and discharge cycle. The changes in the electrochemical performance of the stoichiometric and sulphur-substituted lithium manganese oxide spinels were examined, and suggested explanations for the observed dependencies were given. A strong influence of sulphur introduction into the spinel structure on the chemical stability and electrochemical characteristic was observed. It was demonstrated that the significant improvement in coulombic efficiency and capacity retention of lithium cell with LMOS1 active material arises from a more stable solid electrolyte interphase (SEI layer. Based on EIS studies, the Li ion diffusion coefficients in the cathodes were estimated, and the influence of sulphur on Li+ diffusivity in the spinel structure was established. The obtained results support the assumption that sulphur substitution is an effective way to promote chemical stability and the electrochemical performance of LiMn2O4 cathode material.

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

    Science.gov (United States)

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

    2018-05-05

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

  19. Cathodic electrodeposition of mixed molybdenum tungsten oxides from peroxo-polymolybdotungstate solutions.

    Science.gov (United States)

    Kondrachova, Lilia; Hahn, Benjamin P; Vijayaraghavan, Ganesh; Williams, Ryan D; Stevenson, Keith J

    2006-12-05

    Mixed molybdenum tungsten trioxide films of varying stoichiometry (MoxW1 - xO3, 0 cathodic electrodeposition on indium tin oxide (ITO)-coated glass substrates from aqueous peroxo-polymolybdotungstate solutions. Electrochemical quartz crystal microbalance (EQCM), cyclic voltammetry, and chronocoulometry were used to gain insight into the electrodeposition mechanism. The compositional and structural properties were characterized for MoxW1 - xO3 films deposited at intermediate potentials (-0.35 V vs Ag/AgCl) and sintered at 250 degrees C using energy-dispersive spectroscopy, X-ray diffraction, and Raman spectroscopy. These studies reveal that films consist of homogeneously mixed MoxW1 - xO3, with an enriched Mo content ranging in composition from 0.4 < x < 0.7 depending upon the mol % Mo present in the deposition solution. Chronoamperometry and spectroelectrochemical measurements were conducted to estimate lithium ion diffusion coefficients and coloration efficiencies for the mixed metal oxide films in 1 M LiClO4/propylene carbonate. The subtle interplay between structural and compositional properties due to the uniform mixing of Mo and W oxide components shows that electrochromic and lithium ion transport properties are moderately enhanced relative to those of single-component WO3 and MoO3 and demonstrate improved structural stability over pure MoO3 polymorphs during electrochemical cycling.

  20. Sol-gel prepared active ternary oxide coating on titanium in cathodic protection

    Directory of Open Access Journals (Sweden)

    VLADIMIR V. PANIC

    2007-12-01

    Full Text Available The characteristics of a ternary oxide coating, on titanium, which consisted of TiO2, RuO2 and IrO2 in the molar ratio 0.6:0.3:0.1, calculated on the metal atom, were investigated for potential application for cathodic protection in a seawater environment. The oxide coatings on titanium were prepared by the sol gel procedure from a mixture of inorganic oxide sols, which were obtained by forced hydrolysis of metal chlorides. The morphology of the coating was examined by scanning electron microscopy. The electrochemical properties of activated titanium anodes were investigated by cyclic voltammetry and polarization measurements in a H2SO4- and NaCl-containing electrolyte, as well as in seawater sampled on the Adriatic coast in Tivat, Montenegro. The anode stability during operation in seawater was investigated by the galvanostatic accelerated corrosion stability test. The morphology and electrochemical characteristics of the ternary coating are compared to that of a sol-gel-prepared binary Ti0.6Ru0.4O2 coating. The activity of the ternary coating was similar to that of the binary Ti0.6Ru0.4O2 coating in the investigated solutions. However, the corrosion stability in seawater is found to be considerably greater for the ternary coating.

  1. High Performance Proton-Conducting Solid Oxide Fuel Cells with a Layered Perovskite GdBaCuCoO5+ x Cathode

    Science.gov (United States)

    Zhang, Xiaozhen; Jiang, Yuhua; Hu, Xuebing; Sun, Liangliang; Ling, Yihan

    2018-03-01

    Proton-conducting solid oxide fuel cell (H-SOFC) based on layered perovskite type GdBaCuCoO5+x (GBCC) cathode was fabricated with in situ drop-coating BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte membrane. The influences of Cu doping into Co sites of GdBaCo2O5+ x on the electrical conductivity and conduction mechanism, thermal expansion property and electrochemical performance of cathode materials and corresponding single cell were investigated. Results show that the electrical conductivity decreased and the conduction mechanism would gradually transform to the semiconductor-like behavior. A high maximum power density of 480 mW cm-2 was obtained for the anode supported NiO-BZCY/NiO-BZCY/BZCY/GBCC single cells with wet H2 fuel at 700 °C. The corresponding polarization resistance was as low as 0.17 Ω cm2. The excellent electrochemical performance of as-prepared single cell indicates that GBCC is a good candidate of cathode materials for H-SOFCs.

  2. Lithium Sulfide (Li2S)/Graphene Oxide Nanospheres with Conformal Carbon Coating as a High-Rate, Long-Life Cathode for Li/S Cells.

    Science.gov (United States)

    Hwa, Yoon; Zhao, Juan; Cairns, Elton J

    2015-05-13

    In recent years, lithium/sulfur (Li/S) cells have attracted great attention as a candidate for the next generation of rechargeable batteries due to their high theoretical specific energy of 2600 W·h kg(-1), which is much higher than that of Li ion cells (400-600 W·h kg(-1)). However, problems of the S cathode such as highly soluble intermediate species (polysulfides Li2Sn, n = 4-8) and the insulating nature of S cause poor cycle life and low utilization of S, which prevents the practical use of Li/S cells. Here, a high-rate and long-life Li/S cell is proposed, which has a cathode material with a core-shell nanostructure comprising Li2S nanospheres with an embedded graphene oxide (GO) sheet as a core material and a conformal carbon layer as a shell. The conformal carbon coating is easily obtained by a unique CVD coating process using a lab-designed rotating furnace without any repetitive steps. The Li2S/GO@C cathode exhibits a high initial discharge capacity of 650 mA·h g(-1) of Li2S (corresponding to the 942 mA·h g(-1) of S) and very low capacity decay rate of only 0.046% per cycle with a high Coulombic efficiency of up to 99.7% for 1500 cycles when cycled at the 2 C discharge rate.

  3. Functioning Mechanism of AlF 3 Coating on the Li- and Mn-Rich Cathode Materials

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jianming; Gu, Meng; Xiao, Jie; Polzin, Bryant J.; Yan, Pengfei; Chen, Xilin; Wang, Chongmin; Zhang, Ji-Guang

    2014-11-25

    We report systematic studies of the microstructural changes of uncoated and AlF3-coated Li-rich Mn-rich (LMR) cathode materials (Li1.2Ni0.15Co0.10Mn0.55O2) before and after cycling using a combination of aberration-corrected scanning/transmission electron microscopy (S/TEM) and electron energy loss spectroscopy (EELS). TEM coupled with EELS provides detailed information about the crystallographic and electronic structure changes that occur after cycling, thus revealing the fundamental improvement mechanism of surface coating. The results demonstrate that the surface coating reduces oxidation of the electrolyte at high voltage, suppressing the accumulation of a thick solid electrolyte interface (SEI) layer on electrode particle surface. Surface coating significantly enhances the stability of the surface structure and protects the electrode from severe etching/corrosion by the acidic species in the electrolyte, reducing the formation of etched surfaces and corrosion pits. Moreover, surface coating alleviates the undesirable voltage fade by mitigating layered to spinel-like phase transformation in the bulk region of the material. These fundamental findings may also be widely applied to explain the functioning mechanisms of other surface coatings used in a broad range of electrode materials.

  4. Polycarbonyl(quinonyl) organic compounds as cathode materials for sustainable lithium ion batteries

    International Nuclear Information System (INIS)

    Zeng, Ronghua; Xing, Lidan; Qiu, Yongcai; Wang, Yating; Huang, Wenna; Li, Weishan; Yang, Shihe

    2014-01-01

    Highlights: • Quinonyl compounds containing –OH groups are reported as cathode of sustainable Li-ion battery. • Lithiation potential of these compounds is positively correlated to -OH group number on them. • These compounds exhibit a discharge plateau of 3 V and deliver a capacity of over 180 mAh g -1 at 20 mA g -1 . - Abstract: Suitably designed organic compounds are promising renewable electrode materials for lithium ion batteries (LIBs) with minimal environmental impacts and no CO 2 release. Herein we report a series of polycarbonyl organic compounds with different number of hydroxyl groups, which can be obtained from renewable plants, as cathode materials for LIBs. Density functional theory (DFT) calculations based on the natural bond orbital (NBO) reveal a positive correlation between the reduction potentials and the number of hydroxyl groups, which is borne out experimentally. Anthraquinone (AQ) with three or four -OH groups has the structural advantages for improving the discharge plateaus. Mechanistic studies show that AQ containing neighbouring carbonyl groups and hydroxyl groups facilitates the formation of six or five-membered rings with lithium ion. Charge/discharge tests show that AQ, 1,5-DHAQ, 1,2,7-THAQ, and 1,2,5,8-THAQ can achieve initial discharge capacities of 215, 190, 186 and 180 mAh g -1 at a current density of 20 mA g -1 , corresponding to 84%, 85%, 89% and 91% of their theoretical capacities, respectively

  5. Synthesis of Co-Al-Cl LDH by cathodic material reprocessing from cellular phone batteries

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Fabio Augusto do; Machado, Erica Oliveira; Freitas, Leonardo Luis de; Santana, Laiane Kalita; Canobre, Sheila Cristina, E-mail: fabioamaral@yahoo.com.br, E-mail: fabioamaral@iqufu.ufu.br [Universidade Federal de Uberlandia (UFU/LAETE), (Brazil). Inst. de Quimica. Lab. de Armazenamento de Energia e Tratamento de Efluente

    2014-08-15

    The aim of this paper was the recovering of the cathodic material from discarded lithium ion batteries for obtainment of the lamellar double hydroxides (LDHs) by the co-precipitation method at variable pH in HCl and H{sub 2}O{sub 2} 1:1 (v/v) acid solution containing Co and Al (extracted from cathodic material composed of LiCoO{sub 2} and aluminum foil). These metals were precipitated in LiOH at pH 9 or 11, or NH{sub 4}OH at pH 9 and submitted to the hydrothermal treatment (HT) to improve the structural organization of the LDHs lamellae. After precipitation, the resulting solids were structurally characterized by XRD for phase identification and calculation of the unit cell parameter, thermally by TGA for the identification of the mass loss and morphologically by SEM. The sample obtained by precipitation with LiOH at pH 11 / hydrothermal treatment showed diffraction peaks similar to hydrotalcite, morphological and thermal characteristics similar to the pattern Co-Al-Cl LDH obtained by co-precipitation at constant pH 8. (author)

  6. Anode Supported Solid Oxide Fuel Cells - Deconvolution of Degradation into Cathode and Anode Contributions

    DEFF Research Database (Denmark)

    Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus

    2007-01-01

    The degradation of anode supported cells was studied over 1500 h as function of cell polarization either in air or oxygen on the cathode. Based on impedance analysis, contributions of anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rates...... of the cathode were strongly dependent on the pO(2); they were significantly smaller when testing in oxygen compared to air. Microstructural analysis of the cathode/electrolyte interface of a not-tested reference cell carried out after removal of the cathode showed sharp craters on the electrolyte surface where...

  7. Hydrothermal Synthesis of Nanostructured Manganese Oxide as Cathodic Catalyst in a Microbial Fuel Cell Fed with Leachate

    Science.gov (United States)

    Haoran, Yuan; Lifang, Deng; Tao, Lu; Yong, Chen

    2014-01-01

    Much effort has been devoted to the synthesis of novel nanostructured MnO2 materials because of their unique properties and potential applications as cathode catalyst in Microbial fuel cell. Hybrid MnO2 nanostructures were fabricated by a simple hydrothermal method in this study. Their crystal structures, morphology, and electrochemical characters were carried out by FESEM, N2-adsorption-desorption, and CV, indicating that the hydrothermally synthesized MnO2 (HSM) was structured by nanorods of high aspect ratio and multivalve nanoflowers and more positive than the naturally synthesized MnO2 (NSM), accompanied by a noticeable increase in oxygen reduction peak current. When the HSM was employed as the cathode catalyst in air-cathode MFC which fed with leachate, a maximum power density of 119.07 mW/m2 was delivered, 64.68% higher than that with the NSM as cathode catalyst. Furthermore, the HSM via a 4-e pathway, but the NSM via a 2-e pathway in alkaline solution, and as 4-e pathway is a more efficient oxygen reduction reaction, the HSM was more positive than NSM. Our study provides useful information on facile preparation of cost-effective cathodic catalyst in air-cathode MFC for wastewater treatment. PMID:24723824

  8. Assessment of the cathode contribution to the degradation of anode-supported solid oxide fuel cells

    DEFF Research Database (Denmark)

    Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus

    2008-01-01

    The degradation of anode-supported cells was studied over 1500 h as a function of cell polarization either in air or oxygen on the cathode side. Based on impedance analysis, contributions of the anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rates...... of the cathode were strongly dependent on the pO(2). Microstructural analysis of the cathode/electrolyte interface carried out after removal of the cathode showed craters on the electrolyte surface where the lanthanum strontium manganite (LSM) particles had been located. The changes of shape and size...... of these craters observed after testing correlated with the cell voltage degradation rates. The results can be interpreted in terms of element redistribution at the cathode/electrolyte interface and formation of foreign phases giving rise to a weakening of local contact points of the LSM cathode and yttria...

  9. Control of electrochemical properties of nickel-rich layered cathode materials for lithium ion batteries by variation of the manganese to cobalt ratio

    Science.gov (United States)

    Sun, Ho-Hyun; Choi, Wonchang; Lee, Joong Kee; Oh, In-Hwan; Jung, Hun-Gi

    2015-02-01

    Various Ni-rich layered oxide cathodes (above 0.80 Ni content), such as LiNi1-y-zCoyAlzO2 (NCA), are used in electric vehicles (EVs) due to their high capacity (∼200 mAh g-1 for NCA). However, to improve cycle performance and thermal stability and to ensure longer and safer usage, numerous studies have investigated surface modification, coating, and doping of cathode materials. In this study, we have investigated the characteristics of Li[Ni0.85CoxMn0.15-x]O2 with various Mn to Co ratios (x = 0-0.15) synthesized by a coprecipitation method. The discharge capacities of the Li[Ni0.85CoxMn0.15-x]O2 cathodes are similar at around 206 mAh g-1 at room temperature and 213.8 mAh g-1 at 55 °C between 2.7 and 4.3 V at a 0.2C rate, while the cyclability, thermal stability, and rate capability of all samples differ according to the Mn and Co ratio. The Li[Ni0.85Co0.05Mn0.10]O2 cathode shows the most promising electrochemical properties under different conditions among the various cathodes evaluated; it displays a high rate capacity (approximately 163 mAh g-1 at 5C rate) at 25 °C and good thermal stability (main exothermic temperature of 233.7 °C and relatively low heat evolution of 857.3 J g-1).

  10. Systematic evaluation of Co-free LnBaFe2O5+δ (Ln = Lanthanides or Y) oxides towards the application as cathodes for intermediate-temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Chen Dengjie; Wang Fucun; Shi Huangang; Ran Ran; Shao Zongping

    2012-01-01

    Co-free oxides with a nominal composition of LnBaFe 2 O 5+δ , where Ln = La, Pr, Nd, Sm, Gd, and Y, were synthesized and phase structure, oxygen content, electronic conductivity, oxygen desorption, thermal expansion, microstructure and electrochemical performance were systematically investigated. Among the series of materials tested, LaBaFe 2 O 5+δ oxide showed the largest electronic conductivity and YBaFe 2 O 5+δ oxide had the smallest thermal expansion coefficient (TEC) of 14.6 × 10 −6 K −1 within a temperature range of 200–900 °C. All LnBaFe 2 O 5+δ oxides typically possess the TEC values smaller than 20 × 10 −6 K −1 . The oxygen content, electronic conductivity and TEC values are highly dependent on the cation size of the Ln 3+ dopant. The lowest electrode polarization resistance in air under open circuit voltage condition was obtained for SmBaFe 2 O 5+δ electrode and was approximately 0.043, 0.084, 0.196, 0.506 and 1.348 Ω cm 2 at 800, 750, 700, 650 and 600 °C, respectively. The SmBaFe 2 O 5+δ oxide also demonstrated the best performance after a cathodic polarization. A cell with a SmBaFe 2 O 5+δ cathode delivered peak power densities of 1026, 748, 462, 276 and 148 mW cm −2 at 800, 750, 700, 650 and 600 °C, respectively. The results suggest that certain LnBaFe 2 O 5+δ oxides have sufficient electrochemical performance to be promising candidates for cathodes in intermediate-temperature solid oxide fuel cells.

  11. In situ study of Li-ions diffusion and deformation in Li-rich cathode materials by using scanning probe microscopy techniques

    Science.gov (United States)

    Zeng, Kaiyang; Li, Tao; Tian, Tian

    2017-08-01

    In this paper, the scanning probe microscopy (SPM) based techniques, namely, conductive-AFM, electrochemical strain microscopy (ESM) and AM-FM (amplitude modulation-frequency modulation) techniques, are used to in situ characterize the changes in topography, conductivity and elastic properties of Li-rich layered oxide cathode (Li1.2Mn0.54Ni0.13Co0.13O2) materials, in the form of nanoparticles, when subject to the external electric field. Nanoparticles are the basic building blocks for composite cathode in a Li-ion rechargeable battery. Characterization of the structure and electrochemical properties of the nanoparticles is very important to understand the performance and reliability of the battery materials and devices. In this study, the conductivity, deformation and mechanical properties of the Li-rich oxide nanoparticles under different polarities of biases are studied using the above-mentioned SPM techniques. This information can be correlated with the Li+-ion diffusion and migration in the particles under external electrical field. The results also confirm that the SPM techniques are ideal tools to study the changes in various properties of electrode materials at nano- to micro-scales during or after the ‘simulated’ battery operation conditions. These techniques can also be used to in situ characterize the electrochemical performances of other energy storage materials, especially in the form of the nanoparticles.

  12. Habit plane-driven P2-type manganese-based layered oxide as long cycling cathode for Na-ion batteries

    Science.gov (United States)

    Luo, Rui; Wu, Feng; Xie, Man; Ying, Yao; Zhou, Jiahui; Huang, Yongxin; Ye, Yusheng; Li, Li; Chen, RenJie

    2018-04-01

    Layered transition metal oxides are considered to be promising candidates as cathode materials for sodium-ion batteries. Herein, a facile solid-state reaction is developed to synthesize hexagons plate-like Na0.67Ni0.25Mn0.75O2+δ (denoted as P2-NNM) material with habit plane formed. The structure of this layered oxide is characterized by XRD, HR-TEM and SAED. The layered material delivers a high reversible capacity of 91.8 mAh g-1 at 0.2 C with a capacity retention of 94.4 % after 280 cycles, superior rate capability and long cycle life (84.2 % capacity retention after 1000 cycle). Ni2+ is an active ion and Ni doping alleviates the Jahn-Teller distortion, and Mn3+/Mn4+ coexist as Mn4+ is desired from the stability perspective. Particularly, CV and XPS results confirm these results. Moreover, the electrode exhibits a quasi-solid-solution reaction during the sodium extraction and insertion. This contribution demonstrates that P2-NNM is a promising cathode electrode for rechargeable long-life sodium-ion batteries.

  13. Energy storage in hybrid organic-inorganic materials hexacyanoferrate-doped polypyrrole as cathode in reversible lithium cells

    DEFF Research Database (Denmark)

    Torres-Gomez, G,; Skaarup, Steen; West, Keld

    2000-01-01

    A study of the hybrid oganic-inorganic hexacyanoferrate-polypyrrole material as a cathode in rechargeable lithium cells is reported as part of a series of functional hybrid materials that represent a new concept in energy storage. The effect of synthesis temperatures of the hybrid in the specific...

  14. Improvement of electron emission characteristics of porous silicon emitter by using cathode reduction and electrochemical oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Li, He; Wenjiang, Wang, E-mail: wwj@mail.xjtu.edu.cn; Xiaoning, Zhang

    2017-03-31

    Highlights: • An electron emitter based on porous silicon having the strong application potential was prepared in the studying. • A new simple and convenient post-treat technique was proposed to improve the electron emission properties of the PS emitter. • It demonstrated that the improving of the PS morphology and the oxygen distribution is very important to the PS emitter. - Abstract: A new simple and convenient post-treat technique combined the cathode reduction (CR) and electrochemical oxidation (ECO) was proposed to improve the electron emission properties of the surface-emitting cold cathodes based on the porous silicon (PS). It is demonstrated here that by introducing this new technique combined CR and ECO, the emission properties of the diode have been significantly improved than those as-prepared samples. The experimental results showed that the emission current densities and efficiencies of sample treated by CR were 62 μA/cm{sup 2} and 12.10‰, respectively, nearly 2 orders of magnitude higher than those of as-prepared sample. Furthermore, the CR-treated PS emitter shows higher repeatability and stability compared with the as-prepared PS emitter. The scanning electron microscope (SEM), atomic force microscope (AFM), energy dispersive spectrometer (EDS), furier transformed infrared (FTIR) spectroscopy results indicated that the improved mechanism is mainly due to the passivation of the PS, which not only improve the PS morphology by the passivation of the H{sup +} but also improve the uniformity of the oxygen content distribution in the whole PS layer. Therefore, the method combined the CR treatment and ECO is expected to be a valuable technique to enhance the electron emission characteristics of the PS emitter.

  15. Improvement of electron emission characteristics of porous silicon emitter by using cathode reduction and electrochemical oxidation

    International Nuclear Information System (INIS)

    Li, He; Wenjiang, Wang; Xiaoning, Zhang

    2017-01-01

    Highlights: • An electron emitter based on porous silicon having the strong application potential was prepared in the studying. • A new simple and convenient post-treat technique was proposed to improve the electron emission properties of the PS emitter. • It demonstrated that the improving of the PS morphology and the oxygen distribution is very important to the PS emitter. - Abstract: A new simple and convenient post-treat technique combined the cathode reduction (CR) and electrochemical oxidation (ECO) was proposed to improve the electron emission properties of the surface-emitting cold cathodes based on the porous silicon (PS). It is demonstrated here that by introducing this new technique combined CR and ECO, the emission properties of the diode have been significantly improved than those as-prepared samples. The experimental results showed that the emission current densities and efficiencies of sample treated by CR were 62 μA/cm"2 and 12.10‰, respectively, nearly 2 orders of magnitude higher than those of as-prepared sample. Furthermore, the CR-treated PS emitter shows higher repeatability and stability compared with the as-prepared PS emitter. The scanning electron microscope (SEM), atomic force microscope (AFM), energy dispersive spectrometer (EDS), furier transformed infrared (FTIR) spectroscopy results indicated that the improved mechanism is mainly due to the passivation of the PS, which not only improve the PS morphology by the passivation of the H"+ but also improve the uniformity of the oxygen content distribution in the whole PS layer. Therefore, the method combined the CR treatment and ECO is expected to be a valuable technique to enhance the electron emission characteristics of the PS emitter.

  16. Electrochemically active microorganisms from an acid mine drainage-affected site promote cathode oxidation in microbial fuel cells

    KAUST Repository

    Rojas, Claudia; Vargas, Ignacio T.; Bruns, Mary Ann; Regan, John M.

    2017-01-01

    The limited database of acidophilic or acidotolerant electrochemically active microorganisms prevents advancements on microbial fuel cells (MFCs) operated under low pH. In this study, three MFCs were used to enrich cathodic biofilms using acid mine drainage (AMD) sediments as inoculum. Linear sweep voltammetry showed cathodic current plateaus of 5.5 (± 0.7) mA at about − 170 mV vs Ag/AgCl and 8.5 (± 0.9) mA between − 500 mV to − 450 mV vs Ag/AgCl for biofilms developed on small graphite fiber brushes. After gamma irradiation, biocathodes exhibited a decrease in current density approaching that of abiotic controls. Electrochemical impedance spectroscopy showed six-fold lower charge transfer resistance with viable biofilm. Pyrosequencing data showed that Proteobacteria and Firmicutes dominated the biofilms. Acidithiobacillus representatives were enriched in some biocathodes, supporting the potential importance of these known iron and sulfur oxidizers as cathodic biocatalysts. Other acidophilic chemolithoautotrophs identified included Sulfobacillus and Leptospirillum species. The presence of chemoautotrophs was consistent with functional capabilities predicted by PICRUSt related to carbon fixation pathways in prokaryotic microorganisms. Acidophilic or acidotolerant heterotrophs were also abundant; however, their contribution to cathodic performance is unknown. This study directs subsequent research efforts to particular groups of AMD-associated bacteria that are electrochemically active on cathodes.

  17. Electrochemically active microorganisms from an acid mine drainage-affected site promote cathode oxidation in microbial fuel cells

    KAUST Repository

    Rojas, Claudia

    2017-08-03

    The limited database of acidophilic or acidotolerant electrochemically active microorganisms prevents advancements on microbial fuel cells (MFCs) operated under low pH. In this study, three MFCs were used to enrich cathodic biofilms using acid mine drainage (AMD) sediments as inoculum. Linear sweep voltammetry showed cathodic current plateaus of 5.5 (± 0.7) mA at about − 170 mV vs Ag/AgCl and 8.5 (± 0.9) mA between − 500 mV to − 450 mV vs Ag/AgCl for biofilms developed on small graphite fiber brushes. After gamma irradiation, biocathodes exhibited a decrease in current density approaching that of abiotic controls. Electrochemical impedance spectroscopy showed six-fold lower charge transfer resistance with viable biofilm. Pyrosequencing data showed that Proteobacteria and Firmicutes dominated the biofilms. Acidithiobacillus representatives were enriched in some biocathodes, supporting the potential importance of these known iron and sulfur oxidizers as cathodic biocatalysts. Other acidophilic chemolithoautotrophs identified included Sulfobacillus and Leptospirillum species. The presence of chemoautotrophs was consistent with functional capabilities predicted by PICRUSt related to carbon fixation pathways in prokaryotic microorganisms. Acidophilic or acidotolerant heterotrophs were also abundant; however, their contribution to cathodic performance is unknown. This study directs subsequent research efforts to particular groups of AMD-associated bacteria that are electrochemically active on cathodes.

  18. Study of LiFePO{sub 4} cathode materials coated with high surface area carbon

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Cheng-Zhang; Fey, George Ting-Kuo [Department of Chemical and Materials Engineering, National Central University, Chung-Li 32054 (China); Kao, Hsien-Ming [Department of Chemistry, National Central University, Chung-Li 32054 (China)

    2009-04-01

    LiFePO{sub 4} is a potential cathode material for 4 V lithium-ion batteries. Carbon-coated lithium iron phosphates were prepared using a high surface area carbon to react precursors through a solid-state process, during which LiFePO{sub 4} particles were embedded in amorphous carbon. The carbonaceous materials were synthesized by the pyrolysis of peanut shells under argon, where they were carbonized in a two-step process that occurred between 573 and 873 K. The shells were also treated with a proprietary porogenic agent with the goal of altering the pore structure and surface area of the pyrolysis products. The electrochemical properties of the as-prepared LiFePO{sub 4}/C composite cathode materials were systematically characterized by X-ray diffraction, scanning electron microscope, element mapping, energy dispersive spectroscopy, Raman spectroscopy, and total organic carbon (TOC) analysis. In LiFePO{sub 4}/C composites, the carbon not only increases rate capability, but also stabilizes capacity. In fact, the capacity of the composites increased with the specific surface area of carbon. The best result was observed with a composite made of 8.0 wt.% with a specific surface area of 2099 m{sup 2} g{sup -1}. When high surface area carbon was used as a carbon source to produce LiFePO{sub 4}, overall conductivity increased from 10{sup -8} to 10{sup -4} S cm{sup -1}, because the inhibition of particle growth during the final sintering process led to greater specific capacity, improved cycling properties and better rate capability compared to a pure olivine LiFePO{sub 4} material. (author)

  19. Chemical compatibility of alternative perovskite oxide SOFC cathodes with doped lanthanum gallate solid electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Kostogloudis, G.C.; Ftikos, C. [Laboratory of Inorganic Materials Technology, Department of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Str., Zografou Campus, GR-15780 Athens (Greece); Ahmad-Khanlou, A.; Naoumidis, A.; Stoever, D. [Research Centre Juelich, Institute for Materials and Processes in Energy Systems IWV1, D-52425 Juelich (Germany)

    2000-10-01

    This paper reports on the investigations of the chemical compatibility between SOFC cathode materials with compositions Pr{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Mn{sub 0.8}O{sub 3-{delta}}, Pr{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}}, Pr{sub 0.8}Sr{sub 0.2}Co{sub 0.3}Mn{sub 0.7}O{sub 3-{delta}} and Pr{sub 0.75}Sr{sub 0.2}Co{sub 0.2}Mn{sub 0.8}O{sub 3-{delta}} and the electrolyte materials with compositions La{sub 0.8}Sr{sub 0.2}Ga{sub 0.9}Mg{sub 0.1}O{sub 3-{delta}}, and La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}}. The lanthanum gallate electrolyte with 20 mol.% Sr contained two additional phases, namely, LaSrGa{sub 3}O{sub 7} and LaSrGaO{sub 4}, while that with 10 mol.% Sr was formed in nearly single phase. Two types of experiments were performed: (a) reactivity experiments of powder mixtures and (b) diffusion experiments in cathode/electrolyte double-layer pellets. No reaction products were detected by XRD. High Co diffusion into the electrolyte was identified with SEM/EDX in all diffusion experiments examined. The transition metals diffuse in the order Mncathode, the formation of LaSrGa{sub 3}O{sub 7} second phase was identified on the electrolyte side, near the interdiffusion zone.

  20. Novel Carbon Materials in the Cathode Formulation for High Rate Rechargeable Hybrid Aqueous Batteries

    Directory of Open Access Journals (Sweden)

    Xiao Zhu

    2017-11-01

    Full Text Available Novel carbon materials, carbon nanotubes (CNTs and porous graphene (PG, were exploited and used as conductive additives to improve the rate performance of LiMn2O4 cathode for the rechargeable aqueous Zn/LiMn2O4 battery, namely the rechargeable hybrid aqueous battery (ReHAB. Thanks to the long-range conductivity and stable conductive network provided by CNTs, the rate and cycling performances of LiMn2O4 cathode in ReHAB are highly improved—up to about 100 mAh·g−1 capacity is observed at 10 C (1 C = 120 mAh·g−1. Except for CNTs, porous graphene (PG with a high surface area, an abundant porous structure, and an excellent electrical conductivity facilitates the transportation of Li ions and electrons, which can also obviously enhance the rate capability of the ReHAB. This is important because the ReHAB could be charged/discharged in a few minutes, and this leads to potential application of the ReHAB in automobile industry.

  1. New Redox Polymers that Exhibit Reversible Cleavage of Sulfur Bonds as Cathode Materials.

    Science.gov (United States)

    Baloch, Marya; Ben Youcef, Hicham; Li, Chunmei; Garcia-Calvo, Oihane; Rodriguez, Lide M; Shanmukaraj, Devaraj; Rojo, Teofilo; Armand, Michel

    2016-11-23

    Two new cathode materials based on redox organosulfur polymers were synthesized and investigated for rechargeable lithium batteries as a proof-of-concept study. These cathodes offered good cycling performance owing to the absence of polysulfide solubility, which plagues Li/S systems. Herein, an aliphatic polyamine or a conjugated polyazomethine was used as the base to tether the redox-active species. The activity comes from the cleavage and formation of S-S or N-S bonds, which is made possible by the rigid conjugated backbone. The synthesized polymers were characterized through FTIR spectroscopy and thermogravimetric analysis (TGA). Galvanostatic measurements were performed to evaluate the discharge/charge cycles and characterize the performance of the lithium-based cells, which displayed initial discharge capacities of approximately 300 mA h g -1 at C/5 over 100 cycles with approximately 98 % Coulombic efficiency. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Cathodic processes in high-temperature molten salts for the development of new materials processing methods

    International Nuclear Information System (INIS)

    Schwandt, Carsten

    2017-01-01

    Molten salts play an important role in the processing of a range of commodity materials. This includes the large-scale production of iron, aluminium, magnesium and alkali metals as well as the refining of nuclear fuel materials. This presentation focuses on two more recent concepts in which the cathodic reactions in molten salt electrolytic cells are used to prepare high-value-added materials. Both were developed and advanced at the Department of Materials Science and Metallurgy at the University of Cambridge and are still actively being pursued. One concept is now generally known as the FFC-Cambridge process. The presentation will highlight the optimisation of the process towards high selectivities for tubes or particles depict a modification of the method to synthesize tin-filled carbon nanomaterial, and illustrate the implementation of a novel type of process control to enable the preparation of gramme quantities of material within a few hours with simple laboratory equipment. Also discussed will be the testing of these materials in lithium ion batteries

  3. Molybdate Based Ceramic Negative-Electrode Materials for Solid Oxide Cells

    DEFF Research Database (Denmark)

    Graves, Christopher R.; Reddy Sudireddy, Bhaskar; Mogensen, Mogens Bjerg

    2010-01-01

    Novel molybdate materials with varying Mo valence were synthesized as possible negative-electrode materials for solid oxide cells. The phase, stability, microstructure and electrical conductivity were characterized. The electrochemical activity for H2O and CO2 reduction and H2 and CO oxidation...... enhanced the electrocatalytic activity and electronic conductivity. The polarization resistances of the best molybdates were two orders of magnitude lower than that of donor-doped strontium titanates. Many of the molybdate materials were significantly activated by cathodic polarization, and they exhibited...... higher performance for cathodic (electrolysis) polarization than for anodic (fuel cell) polarization, which makes them especially interesting for use in electrolysis electrodes. ©2010 COPYRIGHT ECS - The Electrochemical Society...

  4. Polyaniline/multi-walled carbon nanotubes composite with core-shell structures as a cathode material for rechargeable lithium-polymer cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pan [School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209 (China); Han, Jia-Jun, E-mail: hanjiajunhitweihai@163.com [School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209 (China); Jiang, Li-Feng [Dalian Chemical Institute of Chinese Academy of Sciences, Dalian 116011 (China); Li, Zhao-Yu; Cheng, Jin-Ning [School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209 (China)

    2017-04-01

    Highlights: • The polyaniline multi-walled carbon nanotubes composite with core-shell structures was synthetized via in situ chemical oxidative polymerization, and the materials were characterized by physical and chemical methods. • The PANI/WMCNTs was synthetized via in situ chemical oxidative polymerization with core-shell structures. • The WMCNTs highly enhanced the conductivity of composites. • The comopsites were more conducive to the intercalation and deintercalation of anions and cations. • The much better performance as the cathode for lithium-ion cells was acquired for the composites. • The composites are low cost and eco-friendly which have a good prospect in future. - Abstract: The aniline was polymerized onto functionalized multi-walled carbon nanotubes in order to obtain a cathode material with core-shell structures for lithium batteries. The structure and morphology of the samples were investigated by Fourier transform infrared spectroscopy analysis, scanning electron microscope, transmission electron microscope and X-ray diffraction. The electrochemical properties of the composite were characterized by the cyclic voltammetry, the charge/discharge property, coulombic efficiency, and ac impedance spectroscopy in detail. At a constant current density of 0.2 C, the first specific discharge capacity of the reduced and oxidized PANI/WMCNTs were 181.8 mAh/g and 135.1 mAh/g separately, and the capacity retention rates were corresponding to 76.75% and 86.04% for 100 cycles with 99% coulombic efficiency. It was confirmed that the CNTs obviously enhanced the conductivity and electrochemical performance of polyaniline, and compared with the pure PANI, the reduced composite possessed a quite good performance for the cathode of lithium batteries.

  5. Effect of doped ceria interlayer on cathode performance of the electrochemical cell using proton conducting oxide

    International Nuclear Information System (INIS)

    Sakai, Takaaki; Matsushita, Shotaro; Hyodo, Junji; Okuyama, Yuji; Matsuka, Maki; Ishihara, Tatsumi; Matsumoto, Hiroshige

    2012-01-01

    Highlights: ► Ce 0.8 Yb 0.2 O 2−δ (YbDC) interlayer conducted a large amount of protons. ► YbDC can work as cathode interlayer for proton conducting electrolyte cells. ► Cathode overpotential of the YbDC interlayer cells showed a plateau at about 400 mV. - Abstract: Introduction of doped ceria interlayer to cathode/electrolyte interface of the electrochemical cell with proton conducting electrolyte was investigated using thin Ce 0.8 Yb 0.2 O 2−δ (YbDC) interlayer of about 500 nm thickness. YbDC interlayer conducted a large amount of protons as much as 170 mA cm −2 . It was also found that cathode overpotential of the YbDC interlayer cells consistently showed a plateau at about 400 mV, at which that of the non-interlayer cells did not show, suggesting a possibility that cathode reaction is changed by introducing the doped ceria interlayer. This result also indicates that the interlayer showed high activity for cathode reaction when enough cathodic bias was applied. Especially, the interlayer showed high activity for the improvement of poor cathode reaction between SrZr 0.9 Y 0.1 O 3−α (SZY-91) electrolyte and platinum cathode.

  6. Cermet cathodes for strontium and magnesium-doped LaGaO3-based solid oxide fuel cells

    International Nuclear Information System (INIS)

    Datta, Pradyot; Bronin, D.I.; Majewski, P.; Aldinger, F.

    2009-01-01

    To check the suitability of La 0.9 Sr 0.1 Ga 0.85 Mg 0.15 O 3-δ -Ag cermets as cathode material for solid oxide fuel cell (SOFC) with Sr- and Mg-doped LaGaO 3 electrolyte a series of cermets with different Ag contents were prepared by conventional sintering process. The chemical compatibility between La 0.9 Sr 0.1 Ga 0.85 Mg 0.15 O 3-δ (LSGM) and Ag was investigated by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Thermal expansion coefficient of the cermets was measured as a function of Ag content and was found to increase with increasing metallic content. Oxygen adsorption at the surface of the cermets could be detected but no reaction or solid solubility between LSGM and Ag was found. It was noticed that a minimum of 30 wt.% Ag is needed to form a cermet with percolating network. From impedance spectroscopy measurement activation energy for the polarization conductance was found to be around 110 kJ mol -1

  7. Cermet cathodes for strontium and magnesium-doped LaGaO{sub 3}-based solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Datta, Pradyot [Technische Universitaet Clausthal, Institut fuer Metallurgie, 42 Robert-Koch Strasse, 38678 Clausthal-Zellerfeld (Germany); Max-Planck-Institut fuer Metallforschung and Institut fuer Nichtmetallische and Anorganische Materialien, Universitaet Stuttgart, Pulvermetallurgisches Laboratorium, Heisenbergstrasse 3, Stuttgart 70569 (Germany)], E-mail: pradyot.datta@gmail.com; Bronin, D.I. [Institute of High-Temperature Electrochemistry of Russian Academy of Sciences, Ekaterinburg 620219, S. Kovalevskoz 22 (Russian Federation); Majewski, P. [University of South Australia, School of Advanced Manufacturing and Mechanical Engineering, Mawson Institute, Mawson Lakes, South Australia 5095 (Australia); Aldinger, F. [Max-Planck-Institut fuer Metallforschung and Institut fuer Nichtmetallische and Anorganische Materialien, Universitaet Stuttgart, Pulvermetallurgisches Laboratorium, Heisenbergstrasse 3, Stuttgart 70569 (Germany)

    2009-03-15

    To check the suitability of La{sub 0.9}Sr{sub 0.1}Ga{sub 0.85}Mg{sub 0.15}O{sub 3-{delta}}-Ag cermets as cathode material for solid oxide fuel cell (SOFC) with Sr- and Mg-doped LaGaO{sub 3} electrolyte a series of cermets with different Ag contents were prepared by conventional sintering process. The chemical compatibility between La{sub 0.9}Sr{sub 0.1}Ga{sub 0.85}Mg{sub 0.15}O{sub 3-{delta}} (LSGM) and Ag was investigated by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Thermal expansion coefficient of the cermets was measured as a function of Ag content and was found to increase with increasing metallic content. Oxygen adsorption at the surface of the cermets could be detected but no reaction or solid solubility between LSGM and Ag was found. It was noticed that a minimum of 30 wt.% Ag is needed to form a cermet with percolating network. From impedance spectroscopy measurement activation energy for the polarization conductance was found to be around 110 kJ mol{sup -1}.

  8. Nanoporous silver cathode surface treated by atomic layer deposition of CeO_x for low-temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Neoh, Ke Chean; Han, Gwon Deok; Kim, Manjin; Kim, Jun Woo; Choi, Hyung Jong; Park, Suk Won; Shim, Joon Hyung

    2016-01-01

    We evaluated the performance of solid oxide fuel cells (SOFCs) with a 50 nm thin silver (Ag) cathode surface treated with cerium oxide (CeO_x) by atomic layer deposition (ALD). The performances of bare and ALD-treated Ag cathodes were evaluated on gadolinia-doped ceria (GDC) electrolyte supporting cells with a platinum (Pt) anode over 300 °C–450 °C. Our work confirms that ALD CeO_x treatment enhances cathodic performance and thermal stability of the Ag cathode. The performance difference between cells using a Ag cathode optimally treated with an ALD CeO_x surface and a reference Pt cathode is about 50% at 450 °C in terms of fuel cell power output in our experiment. The bare Ag cathode completely agglomerated into islands during fuel cell operation at 450 °C, while the ALD CeO_x treatment effectively protects the porosity of the cathode. We also discuss the long-term stability of ALD CeO_x-treated Ag cathodes related to the microstructure of the layers. (paper)

  9. TH-CD-207B-01: BEST IN PHYSICS (IMAGING): Development of High Brightness Multiple-Pixel X-Ray Source Using Oxide Coated Cathodes

    International Nuclear Information System (INIS)

    Kandlakunta, P; Pham, R; Zhang, T

    2016-01-01

    Purpose: To develop and characterize a high brightness multiple-pixel thermionic emission x-ray (MPTEX) source. Methods: Multiple-pixel x-ray sources allow for designs of novel x-ray imaging techniques, such as fixed gantry CT, digital tomosynthesis, tetrahedron beam computed tomography, etc. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide coated cathodes. Oxide cathode is chosen as the electron source due to its high emission current density and low operating temperature. A MPTEX prototype has been developed which may contain up to 41 micro-rectangular oxide cathodes in 4 mm pixel spacing. Electronics hardware was developed for source control and switching. The cathode emission current was evaluated and x-ray measurements were performed to estimate the focal spot size. Results: The oxide cathodes were able to produce ∼110 mA cathode current in pulse mode which corresponds to an emission current density of 0.55 A/cm 2 . The maximum kVp of the MPTEX prototype currently is limited to 100 kV due to the rating of high voltage feedthrough. Preliminary x-ray measurements estimated the focal spot size as 1.5 × 1.3 mm 2 . Conclusion: A MPTEX source was developed with thermionic oxide coated cathodes and preliminary source characterization was successfully performed. The MPTEX source is able to produce an array of high brightness x-ray beams with a fast switching speed.

  10. Free energy for protonation reaction in lithium-ion battery cathode materials

    International Nuclear Information System (INIS)

    Benedek, R.; Thackeray, M. M.; van de Walle, A.

    2008-01-01

    Calculations are performed of free energies for proton-for-lithium-ion exchange reactions in lithium-ion battery cathode materials. First-principles calculations are employed for the solid phases and tabulated ionization potential and hydration energy data for aqueous ions. Layered structures, spinel LiMn 2 O 4 , and olivine LiFePO 4 are considered. Protonation is most favorable energetically in layered systems, such as Li 2 MnO 3 and LiCoO 2 . Less favorable are ion-exchange in spinel LiMn 2 O 4 and LiV 3 O 8 . Unfavorable is the substitution of protons for Li in olivine LiFePO 4 , because of the large distortion of the Fe and P coordination polyhedra. The reaction free energy scales roughly linearly with the volume change in the reaction

  11. Thermal Stability and Reactivity of Cathode Materials for Li-Ion Batteries.

    Science.gov (United States)

    Huang, Yiqing; Lin, Yuh-Chieh; Jenkins, David M; Chernova, Natasha A; Chung, Youngmin; Radhakrishnan, Balachandran; Chu, Iek-Heng; Fang, Jin; Wang, Qi; Omenya, Fredrick; Ong, Shyue Ping; Whittingham, M Stanley

    2016-03-23

    The thermal stability of electrochemically delithiated Li0.1Ni0.8Co0.15Al0.05O2 (NCA), FePO4 (FP), Mn0.8Fe0.2PO4 (MFP), hydrothermally synthesized VOPO4, LiVOPO4, and electrochemically lithiated Li2VOPO4 is investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis, coupled with mass spectrometry (TGA-MS). The thermal stability of the delithiated materials is found to be in the order of NCA cathode is indeed predicted to be marginally less stable than FP but significantly more stable than NCA in the absence of electrolyte. An analysis of the reaction equilibria between VOPO4 and EC using a multicomponent phase diagram approach yields products and reaction enthalpies that are highly consistent with the experiment results.

  12. Multiscale Transient and Steady-State Study of the Influence of Microstructure Degradation and Chromium Oxide Poisoning on Solid Oxide Fuel Cell Cathode Performance

    Science.gov (United States)

    Li, Guanchen; von Spakovsky, Michael R.; Shen, Fengyu; Lu, Kathy

    2018-01-01

    Oxygen reduction in a solid oxide fuel cell cathode involves a nonequilibrium process of coupled mass and heat diffusion and electrochemical and chemical reactions. These phenomena occur at multiple temporal and spatial scales, making the modeling, especially in the transient regime, very difficult. Nonetheless, multiscale models are needed to improve the understanding of oxygen reduction and guide cathode design. Of particular importance for long-term operation are microstructure degradation and chromium oxide poisoning both of which degrade cathode performance. Existing methods are phenomenological or empirical in nature and their application limited to the continuum realm with quantum effects not captured. In contrast, steepest-entropy-ascent quantum thermodynamics can be used to model nonequilibrium processes (even those far-from equilibrium) at all scales. The nonequilibrium relaxation is characterized by entropy generation, which can unify coupled phenomena into one framework to model transient and steady behavior. The results reveal the effects on performance of the different timescales of the varied phenomena involved and their coupling. Results are included here for the effects of chromium oxide concentrations on cathode output as is a parametric study of the effects of interconnect-three-phase-boundary length, oxygen mean free path, and adsorption site effectiveness. A qualitative comparison with experimental results is made.

  13. Effect of CeO2-coating on the electrochemical performances of LiFePO4/C cathode material

    International Nuclear Information System (INIS)

    Yao Jingwen; Wu Feng; Qiu Xinping; Li Ning; Su Yuefeng

    2011-01-01

    Highlights: → The first study the effect of CeO 2 coating on LiFePO 4 /C at low temperature. → Coated cathode shows improved capacities at high rates and low temperature. → CeO 2 -coating decreases electrode polarization and increases charge-transfer reaction activity. - Abstract: The effect of CeO 2 coating on LiFePO 4 /C cathode material has been investigated. The crystalline structure and morphology of the synthesized powders have been characterized by XRD, SEM, TEM and their electrochemical performances both at room temperature and low temperature are evaluated by CV, EIS and galvanostatic charge/discharge tests. It is found that, nano-CeO 2 particles distribute on the surface of LiFePO 4 without destroying the crystal structure of the bulk material. The CeO 2 -coated LiFePO 4 /C cathode material shows improved lithium insertion/extraction capacity and electrode kinetics, especially at high rates and low temperature. At -20 deg. C, the CeO 2 -coated material delivers discharge capacity of 99.7 mAh/g at 0.1C rate and the capacity retention of 98.6% is obtained after 30 cycles at various charge/discharge rates. The results indicate that the surface treatment should be an effective way to improve the comprehensive properties of the cathode materials for lithium ion batteries.

  14. Structural and Electrical Properties of Lithium-Ion Rechargeable Battery Using the LiFePO4/Carbon Cathode Material.

    Science.gov (United States)

    Kim, Young-Sung; Jeoung, Tae-Hoon; Nam, Sung-Pill; Lee, Seung-Hwan; Kim, Jea-Chul; Lee, Sung-Gap

    2015-03-01

    LiFePO4/C composite powder as cathode material and graphite powder as anode material for Li-ion batteries were synthesized by using the sol-gel method. An electrochemical improvement of LiFePO4 materials has been achieved by adding polyvinyl alcohol as a carbon source into as-prepared materials. The samples were characterized by elemental analysis (EA), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-EM). The chemical composition of LiFePO4/C powders was in a good agreement with that of the starting solution. The capacity loss after 500 cycles of LiFePO4/C cell is 11.1% in room temperature. These superior electrochemical properties show that LiFePO4/C composite materials are promising candidates as cathode materials.

  15. A novel vanadium oxide deposit for the cathode of asymmetric lithium-ion supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing-Mei; Hu, Chi-Chang [Department of Chemical Engineering, National Tsing Hua University, Hsin-Chu (China); Chang, Kuo-Hsin [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi (China)

    2010-12-15

    Hydrous vanadium oxide (denoted as VO{sub x}.yH{sub 2}O) deposited at 0.4 V shows promising capacitive behavior in aqueous media containing concentrated Li ions. VO{sub x}.yH{sub 2}O annealed in air at 300 C for 1 h shows highly reversible Li-ion intercalation/de-intercalation behavior with specific capacitance reaching ca. 737 and 606 F g{sup -} {sup 1} at 25 and 500 mV s{sup -1} in 12 M LiCl between -0.2 and 0.8 V. In 14 M LiCl, retention of specific capacitance is about 95% when the scan rate is increased from 25 to 500 mV s{sup -} {sup 1}. This work is the first report showing the ultrahigh rate of Li-ion intercalation/de-intercalation in VO{sub x}.yH{sub 2}O. A so-called Li-ion supercapacitor of the asymmetric type consisting of a VO{sub x}.yH{sub 2}O cathode and a WO{sub 3}{sup .}zH{sub 2}O anode is proposed here. (author)

  16. Influence of a partially oxidized calcium cathode on the performance of polymeric light emitting diodes

    NARCIS (Netherlands)

    Andersson, G.G.; Jong, de M.P.; Janssen, F.J.J.; Sturm, J.M.; IJzendoorn, van L.J.; Denier van der Gon, A.W.; Voigt, de M.J.A.; Brongersma, H.H.

    2001-01-01

    We investigated the influence of the presence of oxygen during the deposition of the calcium cathode on the structure and on the performance of polymeric light emitting diodes (pLEDs). The oxygen background pressure during deposition of the calcium cathode of polymeric LEDs was varied. Subsequently,

  17. Studies of selected synthesis procedures of the conducting LiFePO{sub 4}-based composite cathode materials for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Ojczyk, W.; Marzec, J.; Swierczek, K.; Zajac, W.; Molenda, J. [Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Molenda, M.; Dziembaj, R. [Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow (Poland)

    2007-11-15

    In this paper technological aspects of a synthesis of phospho-olivine LiFePO{sub 4} based composite cathode materials for lithium batteries are presented. An effective synthesis route yielding a highly conductive composite cathode material was developed. The structural, electrical and electrochemical properties of these materials were investigated. It was shown that the enhanced conductivity of the cathode material is due to the presence of a thin layer of the reduced material which has metallic properties, which is formed on the grain surfaces of the phospho-olivine. We propose a synthesis route yielding LiFePO{sub 4}/Fe{sub 2}P composite material. (author)

  18. Evaluation of GdBaCo{sub 2}O{sub 5+{delta}} as cathode material for doped lanthanum gallate electrolyte IT-SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Tarancon, A. [Department of Inorganic Chemistry, University of La Laguna, La Laguna, Tenerife (Spain); EME/XaRMAE/IN, Department of Electronics, University of Barcelona (Spain); Marrero-Lopez, D.; Ruiz-Morales, J.C.; Nunez, P. [Department of Inorganic Chemistry, University of La Laguna, La Laguna, Tenerife (Spain); Pena-Martinez, J.

    2008-10-15

    The layered perovskite GdBaCo{sub 2}O{sub 5+{delta}} (GBCO), recently proposed for intermediate temperature solid oxide fuel cell applications, was investigated and compared with Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF) cathode material using La{sub 0.9}A{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 2.85} (A=Sr,Ba) as electrolytes. Area-specific resistance was measured by impendance spectroscopy in symmetrical cells. The cobaltites were prepared by a modified citrate sol-gel route and tested as cathode materials for doped lanthanum gallate-based cells using dry H{sub 2} as fuel and air as oxidant, rendering power density values of 180 and 240 mW cm {sup -2} at 1,073 K (1 mm thick pellets) for GBCO and BSCF fuel cells, respectively. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  19. Modular cathode assemblies and methods of using the same for electrochemical reduction

    Science.gov (United States)

    Wiedmeyer, Stanley G.; Barnes, Laurel A.; Williamson, Mark A.; Willit, James L.

    2018-03-20

    Modular cathode assemblies are useable in electrolytic reduction systems and include a basket through which fluid electrolyte may pass and exchange charge with a material to be reduced in the basket. The basket can be divided into upper and lower sections to provide entry for the material. Example embodiment cathode assemblies may have any shape to permit modular placement at any position in reduction systems. Modular cathode assemblies include a cathode plate in the basket, to which unique and opposite electrical power may be supplied. Example embodiment modular cathode assemblies may have standardized electrical connectors. Modular cathode assemblies may be supported by a top plate of an electrolytic reduction system. Electrolytic oxide reduction systems are operated by positioning modular cathode and anode assemblies at desired positions, placing a material in the basket, and charging the modular assemblies to reduce the metal oxide.

  20. Vanadium Pentoxide-Based Composite Synthesized Using Microwave Water Plasma for Cathode Material in Rechargeable Magnesium Batteries

    Directory of Open Access Journals (Sweden)

    Tatsuhiko Yajima

    2013-10-01

    Full Text Available Multivalent cation rechargeable batteries are expected to perform well as high-capacity storage devices. Rechargeable magnesium batteries have an advantage in terms of resource utilization and safety. Here, we report on sulfur-doped vanadium pentoxide (S-V2O5 as a potential material for the cathodes of such a battery; S-V2O5 showed a specific capacity of 300 mAh·g−1. S-V2O5 was prepared by a method using a low-temperature plasma generated by carbon felt and a 2.45 GHz microwave generator. This study investigates the ability of S-V2O5 to achieve high capacity when added to metal oxide. The highest recorded capacity (420 mAh·g−1 was reached with MnO2 added to composite SMn-V2O5, which has a higher proportion of included sulfur than found in S-V2O5. Results from transmission electron microscopy, energy-dispersive X-ray spectroscopy, Micro-Raman spectroscopy, and X-ray photoelectron spectroscopy show that the bulk of the SMn-V2O5 was the orthorhombic V2O5 structure; the surface was a xerogel-like V2O5 and a solid solution of MnO2 and sulfur.

  1. Cathode materials produced by spray flame synthesis for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hamid, NoorAshrina Binti A.

    2013-07-03

    Lithium ion batteries are one of the most enthralling rechargeable energy storage systems for portable application due to their high energy density. Nevertheless, with respect to electromobility innovation towards better electrochemical properties such as higher energy and power density is required. Altering the cathode material used in Li-ion batteries is favorable since the mass- and volume performance is closely related to the cathode electrode mass. Instead of using LiCoO{sub 2} as cathode electrode, LiFePO{sub 4} has gained serious attention as this material owns a high theoretical capacity of 170 mAh g{sup -1}. It is non-toxic, cheap and consists of abundant materials but suffers from low electronic and ionic conductivity. Utilization of nanotechnology methods in combination with composite formation is known to cure this problem effectively. In this work, a new combination of techniques using highly scalable gas-phase synthesis namely spray-flame synthesis and subsequent solid-state reaction has been used to synthesize nanocomposite LiFePO{sub 4}/C. At first this work deals with the formation and characterization of nanosize FePO{sub 4} from a solution of iron(III)acetylacetonate and tributyl phosphate in toluene using spray-flame synthesis. It was shown that a subsequent solid state reaction with Li{sub 2}CO{sub 3} and glucose yielded a LiFePO{sub 4}/C nanocomposite with very promising electrochemical properties. Based on these initial findings the influence of two synthesis parameter - carbon content and annealing temperature - was investigated towards the physicochemical properties of LiFePO{sub 4}/C. It was shown that an annealing temperature of 700 C leads to high purity composite materials consisting of crystalline LiFePO{sub 4} with crystallite sizes well below 100 nm and amorphous carbon consisting of disordered and graphite-like carbon. Variation of glucose amount between 10 and 30 wt% resulted in carbon contents between 2.1 and 7.3 wt%. In parallel

  2. Cathode materials produced by spray flame synthesis for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hamid, NoorAshrina Binti A.

    2013-07-03

    Lithium ion batteries are one of the most enthralling rechargeable energy storage systems for portable application due to their high energy density. Nevertheless, with respect to electromobility innovation towards better electrochemical properties such as higher energy and power density is required. Altering the cathode material used in Li-ion batteries is favorable since the mass- and volume performance is closely related to the cathode electrode mass. Instead of using LiCoO{sub 2} as cathode electrode, LiFePO{sub 4} has gained serious attention as this material owns a high theoretical capacity of 170 mAh g{sup -1}. It is non-toxic, cheap and consists of abundant materials but suffers from low electronic and ionic conductivity. Utilization of nanotechnology methods in combination with composite formation is known to cure this problem effectively. In this work, a new combination of techniques using highly scalable gas-phase synthesis namely spray-flame synthesis and subsequent solid-state reaction has been used to synthesize nanocomposite LiFePO{sub 4}/C. At first this work deals with the formation and characterization of nanosize FePO{sub 4} from a solution of iron(III)acetylacetonate and tributyl phosphate in toluene using spray-flame synthesis. It was shown that a subsequent solid state reaction with Li{sub 2}CO{sub 3} and glucose yielded a LiFePO{sub 4}/C nanocomposite with very promising electrochemical properties. Based on these initial findings the influence of two synthesis parameter - carbon content and annealing temperature - was investigated towards the physicochemical properties of LiFePO{sub 4}/C. It was shown that an annealing temperature of 700 C leads to high purity composite materials consisting of crystalline LiFePO{sub 4} with crystallite sizes well below 100 nm and amorphous carbon consisting of disordered and graphite-like carbon. Variation of glucose amount between 10 and 30 wt% resulted in carbon contents between 2.1 and 7.3 wt%. In parallel

  3. Mechanistic modelling of a cathode-supported solid oxide fuel cell. Paper no. IGEC-1-103

    International Nuclear Information System (INIS)

    Suwanwarangkul, R.; Croiset, E.; Pritzker, M.D.; Fowler, M.W.; Douglas, P.L.; Entchev, E.

    2005-01-01

    A model for a cathode-supported tubular solid oxide fuel cell operating with humidified H 2 has been developed. Momentum-, mass-, energy- and charge-transport equations coupled with electrochemical reactions (H 2 oxidation and O 2 reduction) are considered in the model. The model also takes into account the radiative heat transfer between the cell and air-preheating tube. The model is validated against published experimental data ands shows a good agreement. The distributions of temperature, current density, reversible cell voltage, overpotential and species mole fractions within the cell are discussed in detail. (author)

  4. Layered perovskite PrBa0.5Sr0.5CoCuO5+δ as a cathode for intermediate-temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Wang, Biao; Long, Guohui; Ji, Yuan; Pang, Mingjun; Meng, Xiangwei

    2014-01-01

    Highlights: • A single-phase layered-perovskite PrBa 0.5 Sr 0.5 CoCuO 5+δ (PBSCCu) is prepared by the EDTA–citrate complexing method. • PBSCCu cathode has a good chemical compatible with GDC electrolyte. • Partial substitution of Cu for Co can efficiently lower the thermal expansion coefficient. • Performances of PrBa 0.5 Sr 0.5 CoCuO 5+δ cathode based on Gd 0.1 Ce 0.9 O 1.95 electrolyte is reported firstly. - Abstract: Layered perovskite PrBa 0.5 Sr 0.5 CoCuO 5+δ (PBSCCo) oxide is synthesized by EDTA–citrate complexing method and investigated as a novel cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). X-ray diffraction results show that PBSCCo is chemical compatible with Gd 0.1 Ce 0.9 O 1.95 (GDC) electrolyte below 950 °C. The thermal expansion coefficient of PBSCCo is 17.58 × 10 −6 K −1 between 30 °C and 900 °C. The maximum electrical conductivity of PBSCCo is 483 S cm −1 at 325 °C. The polarization resistance of PBSCCo cathode on GDC electrolyte is as low as 0.06 Ω cm 2 at 800 °C. The maximum power density of the electrolyte-supported single cell with PBSCCo cathode achieves 521 mW cm −2 at 800 °C. Preliminary results indicate that PBSCCo is a potential cathode material for application in IT-SOFCs

  5. Synthesis and electrochemical behavior of nanosized LiNi1-xCa xO2 cathode materials for high voltage secondary lithium-ion cells

    International Nuclear Information System (INIS)

    Sathiyamoorthi, R.; Vasudevan, T.

    2007-01-01

    A new class of LiNi 1-x Ca x O 2 (x = 0.0, 0.1, 0.2, 0.3 and 0.5) layered oxide materials has been synthesized by a simple low temperature solid-state route with mixed nitrates/urea with glycerol as the starting materials. First we have taken TG/DTA for observing the phase transformations of LiNi 0.9 Ca 0.1 O 2 . The structure of the synthesized oxides was analyzed using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) to identify the crystal structure and cation environment, respectively. The synthesized ceramic oxide battery materials were examined by using transmission electron microscope (TEM), scanning electron microscope (SEM) analysis to determine the particle size, nature and morphological structure. SEM with energy dispersive X-ray spectroscopic analysis (EDAX) analysis was carried out to explore the composition of the prepared materials. The electrochemical performance of LiNi 1-x Ca x O 2 electrodes was analyzed using cyclic voltammetry (CV) and galvanostatic charge-discharge cycling studies in the voltage range 3.0-4.5 V. Electrode made with cathode active material, acetylene black and poly(vinylidene difluoride) yield a discharge capacity of 178.1 mAh g -1 (x = 0.2) with good specific capacity over several charge-discharge cycles. These results have been also supported by cyclic voltammograms

  6. The 2016 oxide electronic materials and oxide interfaces roadmap

    DEFF Research Database (Denmark)

    Lorenz, M.; Rao, M. S. Ramachandra; Venkatesan, T.

    2016-01-01

    of these materials to understand the tunability of their properties and the novel properties that evolve due to their nanostructured nature is another facet of the challenge. The research related to the oxide electronic field is at an impressionable stage, and this has motivated us to contribute with a roadmap......, Pentcheva, and Gegenwart. Finally, Miletto Granozio presents the European action ‘towards oxide-based electronics’ which develops an oxide electronics roadmap with emphasis on future nonvolatile memories and the required technologies.In summary, we do hope that this oxide roadmap appears as an interesting...

  7. Preparation of mesohollow and microporous carbon nanofiber and its application in cathode material for lithium–sulfur batteries

    International Nuclear Information System (INIS)

    Wu, Yuanhe; Gao, Mingxia; Li, Xiang; Liu, Yongfeng; Pan, Hongge

    2014-01-01

    Highlights: • Mesohollow and microporous carbon fibers were prepared via electrospinning and carbonization. • Sulfur (S) incorporated into the porous fibers by thermal heating in 60 wt.%, forming composite. • S fills fully in the micropores and partially in the mesohollows of the carbon fibers. • The composite shows high capacity and capacity retention as cathode material for Li–S batteries. • Mesohollow and microporous structure is effective in improving the property of S cathode. - Abstract: Mesohollow and microporous carbon nanofibers (MhMpCFs) were prepared by a coaxial electrospinning with polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) as outer and inner spinning solutions followed by a carbonization. The carbon fibers were thermal treated with sublimed sulfur to form S/MhMpCFs composite, which was used as cathode material for lithium–sulfur batteries. Electrochemical study shows that the S/MhMpCFs cathode material provides a maximum capacity of 815 mA h/g after several cycles of activation, and the capacity retains 715 mA h/g after 70 cycles, corresponding to a retention of 88%. The electrochemical property of the S/MhMpCFs composite is much superior than the S-incorporated solid carbon fibers prepared from electrospinning of single PAN. The mechanism of the enhanced electrochemical property of the S/MhMpCFs composite is discussed

  8. High-Thermal- and Air-Stability Cathode Material with Concentration-Gradient Buffer for Li-Ion Batteries.

    Science.gov (United States)

    Shi, Ji-Lei; Qi, Ran; Zhang, Xu-Dong; Wang, Peng-Fei; Fu, Wei-Gui; Yin, Ya-Xia; Xu, Jian; Wan, Li-Jun; Guo, Yu-Guo

    2017-12-13

    Delivery of high capacity with high thermal and air stability is a great challenge in the development of Ni-rich layered cathodes for commercialized Li-ion batteries (LIBs). Herein we present a surface concentration-gradient spherical particle with varying elemental composition from the outer end LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM) to the inner end LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA). This cathode material with the merit of NCM concentration-gradient protective buffer and the inner NCA core shows high capacity retention of 99.8% after 200 cycles at 0.5 C. Furthermore, this cathode material exhibits much improved thermal and air stability compared with bare NCA. These results provide new insights into the structural design of high-performance cathodes with high energy density, long life span, and storage stability materials for LIBs in the future.

  9. Mitigation of chromium poisoning of cathodes in solid oxide fuel cells employing CuMn1.8O4 spinel coating on metallic interconnect

    Science.gov (United States)

    Wang, Ruofan; Sun, Zhihao; Pal, Uday B.; Gopalan, Srikanth; Basu, Soumendra N.

    2018-02-01

    Chromium poisoning is one of the major reasons for cathode performance degradation in solid oxide fuel cells (SOFCs). To mitigate the effect of Cr-poisoning, a protective coating on the surface of interconnect for suppressing Cr vaporization is necessary. Among the various coating materials, Cu-Mn spinel coating is considered to be a potential candidate due to their good thermal compatibility, high stability and good electronic conductivity at high temperature. In this study, Crofer 22 H meshes with no protective coating, those with commercial CuMn2O4 spinel coating and the ones with lab-developed CuMn1.8O4 spinel coating were investigated. The lab-developed CuMn1.8O4 spinel coating were deposited on Crofer 22 H mesh by electrophoretic deposition and densified by a reduction and re-oxidation process. With these different Crofer 22 H meshes (bare, CuMn2O4-coated, and CuMn1.8O4-coated), anode-supported SOFCs with Sr-doped LaMnO3-based cathode were electrochemically tested at 800 °C for total durations of up to 288 h. Comparing the mitigating effects of the two types of Cu-Mn spinel coatings on Cr-poisoning, it was found that the performance of the denser lab-developed CuMn1.8O4 spinel coating was distinctly better, showing no degradation in the cell electrochemical performance and significantly less Cr deposition near the cathode/electrolyte interface after the test.

  10. Improvement in high-voltage and high rate cycling performance of nickel-rich layered cathode materials via facile chemical vapor deposition with methane

    International Nuclear Information System (INIS)

    Hyuk Son, In; Park, Kwangjin; Hwan Park, Jong

    2017-01-01

    Nickel-rich layered-oxide materials are considered promising candidates for application as cathode material in high-energy lithium ion batteries. However, their cycling performance at high voltages and rate conditions require further improvement for the purpose of commercialization. Here, we report on the facile surface modification of nickel-rich layered oxide by chemical vapor deposition with methane which yields a conductive and protective artificial solid electrolyte interphase layer consisting of amorphous carbon, alkyl lithium carbonate, and lithium carbonate. We examine the mechanism of the protective layer formation and structural deformation of the nickel-rich layered oxide during chemical vapor deposition with methane. Via optimizing the reaction conditions, we improve the electrical conductivity as well as the interfacial stability of the nickel-rich layered oxide without inducing structural deformation. The surface-modified nickel-rich layered oxide exhibits an improved performance due to the resulting enhanced rate capability, high initial efficiency, and long cycle life at high voltage (>4.5 V).

  11. Thermochemically active iron titanium oxide materials

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Eric Nicholas; Miller, James E.

    2018-01-16

    A thermal oxidation-reduction cycle is disclosed that uses iron titanium oxide as the reactive material. The cycle may be used for the thermal splitting of water and/or carbon dioxide to form hydrogen and/or carbon monoxide. The formed compounds may be used as syngas precursors to form fuels.

  12. Intercalation of Mg-ions in layered V2O5 cathode materials for rechargeable Mg-ion batteries

    DEFF Research Database (Denmark)

    Sørensen, Daniel Risskov; Johannesen, Pætur; Christensen, Christian Kolle

    The development of functioning rechargeable Mg-ion batteries is still in its early stage, and a coarse screening of suitable cathode materials is still on-going. Within the intercalation-type cathodes, layered crystalline materials are of high interest as they are known to perform well in Li-ion...... intercalation batteries and are also increasingly being explored for Na-ion batteries. Here, we present an investigation of the layered material orthorhombic V2O5, which is a classical candidate for an ion-intercalation material having a high theoretical capacity1. We present discharge-curves for the insertion...... discharge. This indicates that the degradation is highly associated with formation of ion-blocking layers on the anode....

  13. Structural changes and thermal stability of charged LiNixMnyCozO₂ cathode materials studied by combined in situ time-resolved XRD and mass spectroscopy.

    Science.gov (United States)

    Bak, Seong-Min; Hu, Enyuan; Zhou, Yongning; Yu, Xiqian; Senanayake, Sanjaya D; Cho, Sung-Jin; Kim, Kwang-Bum; Chung, Kyung Yoon; Yang, Xiao-Qing; Nam, Kyung-Wan

    2014-12-24

    Thermal stability of charged LiNixMnyCozO2 (NMC, with x + y + z = 1, x:y:z = 4:3:3 (NMC433), 5:3:2 (NMC532), 6:2:2 (NMC622), and 8:1:1 (NMC811)) cathode materials is systematically studied using combined in situ time-resolved X-ray diffraction and mass spectroscopy (TR-XRD/MS) techniques upon heating up to 600 °C. The TR-XRD/MS results indicate that the content of Ni, Co, and Mn significantly affects both the structural changes and the oxygen release features during heating: the more Ni and less Co and Mn, the lower the onset temperature of the phase transition (i.e., thermal decomposition) and the larger amount of oxygen release. Interestingly, the NMC532 seems to be the optimized composition to maintain a reasonably good thermal stability, comparable to the low-nickel-content materials (e.g., NMC333 and NMC433), while having a high capacity close to the high-nickel-content materials (e.g., NMC811 and NMC622). The origin of the thermal decomposition of NMC cathode materials was elucidated by the changes in the oxidation states of each transition metal (TM) cations (i.e., Ni, Co, and Mn) and their site preferences during thermal decomposition. It is revealed that Mn ions mainly occupy the 3a octahedral sites of a layered structure (R3̅m) but Co ions prefer to migrate to the 8a tetrahedral sites of a spinel structure (Fd3̅m) during the thermal decomposition. Such element-dependent cation migration plays a very important role in the thermal stability of NMC cathode materials. The reasonably good thermal stability and high capacity characteristics of the NMC532 composition is originated from the well-balanced ratio of nickel content to manganese and cobalt contents. This systematic study provides insight into the rational design of NMC-based cathode materials with a desired balance between thermal stability and high energy density.

  14. A novel layered perovskite cathode for proton conducting solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Hanping [Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei 230026 (China); Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States); Xue, Xingjian [Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States); Liu, Xingqin; Meng, Guangyao [Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei 230026 (China)

    2010-02-01

    BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{delta}} (BZCY7) exhibits adequate proton conductivity as well as sufficient chemical and thermal stability over a wide range of SOFC operating conditions, while layered SmBa{sub 0.5}Sr{sub 0.5}Co{sub 2}O{sub 5+{delta}} (SBSC) perovskite demonstrates advanced electrochemical properties based on doped ceria electrolyte. This research fully takes advantage of these advanced properties and develops novel protonic ceramic membrane fuel cells (PCMFCs) of Ni-BZCY7 vertical stroke BZCY7 vertical stroke SBSC. The results show that the open-circuit potential of 1.015 V and maximum power density of 533 mW cm{sup -2} are achieved at 700 C. With temperature increase, the total cell resistance decreases, among which electrolyte resistance becomes increasingly dominant over polarization resistance. The results also indicate that SBSC perovskite cathode is a good candidate for intermediate temperature PCMFC development, while the developed Ni-BZCY7 vertical stroke BZCY7 vertical stroke SBSC cell is a promising functional material system for next generation SOFCs. (author)

  15. Depression cathode structure for cathode ray tubes having surface smoothness and method for producing same

    International Nuclear Information System (INIS)

    Rychlewski, T.V.

    1984-01-01

    Depression cathode structures for cathode ray tubes are produced by dispensing liquid cathode material into the depression of a metallic supporting substrate, removing excess cathode material by passing a doctor blade across the substrate surface and over the depression, and drying the cathode layer to a substantially immobile state. The cathode layer may optionally be further shaped prior to substantially complete drying thereof

  16. Room temperature large-scale synthesis of layered frameworks as low-cost 4 V cathode materials for lithium ion batteries

    Science.gov (United States)

    Hameed, A. Shahul; Reddy, M. V.; Nagarathinam, M.; Runčevski, Tomče; Dinnebier, Robert E; Adams, Stefan; Chowdari, B. V. R.; Vittal, Jagadese J.

    2015-01-01

    Li-ion batteries (LIBs) are considered as the best available technology to push forward the production of eco-friendly electric vehicles (EVs) and for the efficient utilization of renewable energy sources. Transformation from conventional vehicles to EVs are hindered by the high upfront price of the EVs and are mainly due to the high cost of LIBs. Hence, cost reduction of LIBs is one of the major strategies to bring forth the EVs to compete in the market with their gasoline counterparts. In our attempt to produce cheaper high-performance cathode materials for LIBs, an rGO/MOPOF (reduced graphene oxide/Metal-Organic Phosphate Open Framework) nanocomposite with ~4 V of operation has been developed by a cost effective room temperature synthesis that eliminates any expensive post-synthetic treatments at high temperature under Ar/Ar-H2. Firstly, an hydrated nanocomposite, rGO/K2[(VO)2(HPO4)2(C2O4)]·4.5H2O has been prepared by simple magnetic stirring at room temperature which releases water to form the anhydrous cathode material while drying at 90 °C during routine electrode fabrication procedure. The pristine MOPOF material undergoes highly reversible lithium storage, however with capacity fading. Enhanced lithium cycling has been witnessed with rGO/MOPOF nanocomposite which exhibits minimal capacity fading thanks to increased electronic conductivity and enhanced Li diffusivity. PMID:26593096

  17. Room temperature large-scale synthesis of layered frameworks as low-cost 4 V cathode materials for lithium ion batteries

    Science.gov (United States)

    Hameed, A. Shahul; Reddy, M. V.; Nagarathinam, M.; Runčevski, Tomče; Dinnebier, Robert E.; Adams, Stefan; Chowdari, B. V. R.; Vittal, Jagadese J.

    2015-11-01

    Li-ion batteries (LIBs) are considered as the best available technology to push forward the production of eco-friendly electric vehicles (EVs) and for the efficient utilization of renewable energy sources. Transformation from conventional vehicles to EVs are hindered by the high upfront price of the EVs and are mainly due to the high cost of LIBs. Hence, cost reduction of LIBs is one of the major strategies to bring forth the EVs to compete in the market with their gasoline counterparts. In our attempt to produce cheaper high-performance cathode materials for LIBs, an rGO/MOPOF (reduced graphene oxide/Metal-Organic Phosphate Open Framework) nanocomposite with ~4 V of operation has been developed by a cost effective room temperature synthesis that eliminates any expensive post-synthetic treatments at high temperature under Ar/Ar-H2. Firstly, an hydrated nanocomposite, rGO/K2[(VO)2(HPO4)2(C2O4)]·4.5H2O has been prepared by simple magnetic stirring at room temperature which releases water to form the anhydrous cathode material while drying at 90 °C during routine electrode fabrication procedure. The pristine MOPOF material undergoes highly reversible lithium storage, however with capacity fading. Enhanced lithium cycling has been witnessed with rGO/MOPOF nanocomposite which exhibits minimal capacity fading thanks to increased electronic conductivity and enhanced Li diffusivity.

  18. Characterization and electrochemical performances of MoO2 modified LiFePO4/C cathode materials synthesized by in situ synthesis method

    International Nuclear Information System (INIS)

    He, Jichuan; Wang, Haibin; Gu, Chunlei; Liu, Shuxin

    2014-01-01

    Graphical abstract: The MoO 2 modified LiFePO 4 /C cathode materials were synthesized by in situ synthesis method. MoO 2 can sufficiently coat on the LiFePO 4 /C particles surface and does not alter LiFePO 4 crystal structure, and the adding of MoO 2 decreases the particles size and increases the tap density of cathode materials. The existence of MoO 2 improves electrochemical performance of LiFePO 4 cathode materials in specific capability and lithium ion diffusion and charge transfer resistance of cathode materials. - Highlights: • The MoO 2 modified LiFePO 4 /C cathode materials were synthesized by in situ synthesis method. • The existence of MoO 2 decreases the particles size and increases the tap density of cathode materials. • MoO 2 can sufficiently coat on the surface of LiFePO 4 /C cathode materials. • The existence of MoO 2 enhanced electrochemical performance of LiFePO 4 /C cathode materials. - Abstract: The MoO 2 modified LiFePO 4 /C cathode materials were synthesized by in situ synthesis method. Phase compositions and microstructures of the products were characterized by X-ray powder diffraction (XRD), SEM, TEM and EDS. Results indicate that MoO 2 can sufficiently coat on the LiFePO 4 surface and does not alter LiFePO 4 crystal structure, the existence of MoO 2 decreases the particles size and increases the tap density of cathode materials. The electrochemical behavior of cathode materials was analyzed using galvanostatic measurement, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results show that the existence of MoO 2 improves electrochemical performance of LiFePO 4 cathode materials in specific capability and lithium ion diffusion and charge transfer resistance. The initial charge–discharge specific capacity and apparent lithium ion diffusion coefficient increase, the charge transfer resistance decreases with MoO 2 content and maximizes around the MoO 2 content is 5 wt%. It has been had further proved that

  19. A simple route to improve rate performance of LiFePO4/reduced graphene oxide composite cathode by adding Mg2+ via mechanical mixing

    Science.gov (United States)

    Huang, Yuan; Liu, Hao; Gong, Li; Hou, Yanglong; Li, Quan

    2017-04-01

    Introducing Mg2+ to LiFePO4 and reduced graphene oxide composite via mechanical mixing and annealing leads to largely improved rate performance of the cathode (e.g. ∼78 mA h g-1 at 20 C for LiFePO4 and reduced graphene oxide composite with Mg2+ introduction vs. ∼37 mA h g-1 at 20 C for LiFePO4 and reduced graphene oxide composite). X-ray photoelectron spectroscopy unravels that the enhanced reduction of Fe2+ to Fe0 occurs in the simultaneous presence of Mg2+ and reduced graphene oxide, which is beneficial for the rate capability of cathode. The simple fabrication process provides a simple and effective means to improve the rate performance of the LiFePO4 and reduced graphene oxide composite cathode.

  20. Core-shell LiFePO4 /carbon-coated reduced graphene oxide hybrids for high-power lithium-ion battery cathodes.

    Science.gov (United States)

    Ha, Sung Hoon; Lee, Yun Jung

    2015-01-26

    Core-shell carbon-coated LiFePO4 nanoparticles were hybridized with reduced graphene (rGO) for high-power lithium-ion battery cathodes. Spontaneous aggregation of hydrophobic graphene in aqueous solutions during the formation of composite materials was precluded by employing hydrophilic graphene oxide (GO) as starting templates. The fabrication of true nanoscale carbon-coated LiFePO4 -rGO (LFP/C-rGO) hybrids were ascribed to three factors: 1) In-situ polymerization of polypyrrole for constrained nanoparticle synthesis of LiFePO4 , 2) enhanced dispersion of conducting 2D networks endowed by colloidal stability of GO, and 3) intimate contact between active materials and rGO. The importance of conducting template dispersion was demonstrated by contrasting LFP/C-rGO hybrids with LFP/C-rGO composites in which agglomerated rGO solution was used as the starting templates. The fabricated hybrid cathodes showed superior rate capability and cyclability with rates from 0.1 to 60 C. This study demonstrated the synergistic combination of nanosizing with efficient conducting templates to afford facile Li(+) ion and electron transport for high power applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Preparation and characterization of Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3} composite oxide formed by cathodic electroplating and anodizing

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Joo-Hee; Kim, Tae-Yoo; Kim, Nam-Jeong; Lee, Chang-Hyoung; Park, Eun-Mi [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Park, Chan [Division of Materials Science and Engineering, Pukyong National University, Busan 608-739 (Korea, Republic of); Suh, Su-Jeong, E-mail: suhsj@skku.ac.kr [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Advanced Materials and Process Research Center for IT, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2011-11-15

    Highlights: > We fabricate Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3}/Al film for high performance thin film capacitor. > The optimum condition of electrolyte composition will coat NbO{sub x} on Al without corrosion of Al during the cathodic electroplating. > Increasing annealing temperature will form Nb{sub 2}O{sub 5} crystalline. > The Al{sub 2}O{sub 3} layer will form between Nb{sub 2}O{sub 5} layer and metal Al after anodizing and the thin film capacitor with Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3}/Al improve dielectric properties. - Abstract: Al foil was coated with niobium oxide by cathodic electroplating and anodized in a neutral boric acid solution to achieve high capacitance in a thin film capacitor. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) revealed the niobium oxide layer on Al to be a hydroxide-rich amorphous phase. The film was crystalline and had stoichiometric stability after annealing at temperatures up to 600 deg. C followed by anodizing at 500 V, and the specific capacitance of the Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3} composite oxide was approximately 27% higher than that of Al{sub 2}O{sub 3} without a Nb{sub 2}O{sub 5} layer. The capacitance was quite stable to the resonance frequency. Overall, the Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3} composite oxide film is a suitable material for thin film capacitors.

  2. Influence of annealing temperature on the electrochemical and surface properties of the 5-V spinel cathode material LiCr0.2Ni0.4Mn1.4O4 synthesized by a sol–gel technique

    DEFF Research Database (Denmark)

    Younesi, Reza; Malmgren, Sara; Edström, Kristina

    2014-01-01

    LiCr0.2Ni0.4Mn1.4O4 was synthesized by a sol–gel technique in which tartaric acid was used as oxide precursor. The synthesized powder was annealed at five different temperatures from 600 to 1,000 °C and tested as a 5-V cathode material in Li-ion batteries. The study shows that annealing at higher...

  3. Synthesis of Three-Dimensional Nanoporous Li-Rich Layered Cathode Oxides for High Volumetric and Power Energy Density Lithium-Ion Batteries.

    Science.gov (United States)

    Qiu, Bao; Yin, Chong; Xia, Yonggao; Liu, Zhaoping

    2017-02-01

    As rechargeable Li-ion batteries have expanded their applications into on-board energy storage for electric vehicles, the energy and power must be increased to meet the new demands. Li-rich layered oxides are one of the most promising candidate materials; however, it is very difficult to make them compatible with high volumetric energy density and power density. Here, we develop an innovative approach to synthesize three-dimensional (3D) nanoporous Li-rich layered oxides Li[Li 0.144 Ni 0.136 Co 0.136 Mn 0.544 ]O 2 , directly occurring at deep chemical delithiation with carbon dioxide. It is found that the as-prepared material presents a micrometer-sized spherical structure that is typically composed of interconnected nanosized subunits with narrow distributed pores at 3.6 nm. As a result, this unique 3D micro-/nanostructure not only has a high tap density over 2.20 g cm -3 but also exhibits excellent rate capability (197.6 mA h g -1 at 1250 mA g -1 ) as an electrode. The excellent electrochemical performance is ascribed to the unique nanoporous micro-nanostructures, which facilitates the Li + diffusion and enhances the structural stability of the Li-rich layered cathode materials. Our work offers a comprehensive designing strategy to construct 3D nanoporous Li-rich layered oxides for both high volumetric energy density and power density in Li-ion batteries.

  4. Fabrication and electrochemical properties of cathode-supported solid oxide fuel cells via slurry spin coating

    International Nuclear Information System (INIS)

    Chen Min; Luo Jingli; Chuang, Karl T.; Sanger, Alan R.

    2012-01-01

    Highlights: ► LSM cathode-supported cell prepared by slurry spin coating. ► Optimizing porosity in CFL resulting in power density of 0.58 W cm −2 at 850 °C. ► Activation polarization govern the impedance arcs measured under the OCV condition. ► Concentration polarization can induce the change of activation polarization. ► Four kinds of polarizations of our cells are separated and investigated. - Abstract: A cathode-supported SOFC consisting of LSM (La 0.8 Sr 0.2 MnO 3−δ ) cathode supporter, LSM–Sm 0.2 Ce 0.8 O 2−δ (SDC) cathode functional layer (CFL), yttria stabilized zirconia (YSZ)/SDC bi-layered electrolyte and Ni-YSZ anode layer was fabricated by a slurry spin coating technique. The influence of the porosity in both the CFL and cathode supporter on the electrochemical properties of the cells has been investigated. It was found that properly controlling the porosity in the CFL would improve the performance of the cells using O 2 in the cathode side (O 2 -cells), with a maximum power density (MPD) value achieving as high as 0.58 W cm −2 at 850 °C. However, this improvement is not so evident for the cells using air in the cathode side (air-cells). When increasing the porosity in the cathode-supporter, a significant increase of the power density for the air cells due to the decreasing R conc,c (cathode concentration polarization to the cell resistance) can be ascertained. In terms of our analysis on various electrochemical parameters, the R act (activation polarization to the cell resistance) is assumed to be mainly responsible for the impedance arcs measured under the OCV condition, with a negligible R conc,c value being able to be detected in our impedances. In this case, a significant decreasing size of the impedance arcs due to the increasing porosity in the cathode supporter would correspond to a decrease of the R act values, which was proved to be induced by the decreasing R conc,c .

  5. Effects of cathode pulse at high frequency on structure and composition of Al2TiO5 ceramic coatings on Ti alloy by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Yao Zhongping; Liu Yunfu; Xu Yongjun; Jiang Zhaohua; Wang Fuping

    2011-01-01

    Research highlights: → Al 2 TiO 5 in the coating on Ti alloy by PEO treatment changes with the increase of the cathode pulse, regardless of the amount and the grain size. → The cathode pulse brings about the decrease of γ-Al 2 O 3 and the increase of rutile TiO 2 in the coating. → The appropriate cathode pulse during PEO process is beneficial to reduce residual discharging channels and improve the density of the coating. - Abstract: The aim of this work is to investigate the effects of cathode pulse under high working frequency on structure and composition of ceramic coatings on Ti-6Al-4V alloys by plasma electrolytic oxidation (PEO). Ceramic coatings were prepared on Ti alloy by pulsed bi-polar plasma electrolytic oxidation in NaAlO 2 solution. The phase composition, morphology and element distribution in the coating were investigated by X-ray diffractometry, scanning electron microscopy and energy distribution spectroscopy, respectively. The coating was mainly composed of a large amount of Al 2 TiO 5 . As the cathode pulse was increased, the amount and grain size of Al 2 TiO 5 were first increased, and then decreased. γ-Al 2 O 3 in the coating was gradually decreased to nothing with the increase in the cathode pulse whereas rutile TiO 2 began to form in the coating. As opposed to the single-polar anode pulse mode, the cathode pulse reduced the thickness of the coatings. However, as the cathode pulse intensity continued to increase, the coating then became thicker regardless of cathode current density or pulse width. In addition, the residual discharging channels were reduced and the density of the coating was increased with the appropriate increase of the cathode pulse.

  6. Cathodic Polarization Coats Titanium Based Implant Materials with Enamel Matrix Derivate (EMD

    Directory of Open Access Journals (Sweden)

    Matthias J. Frank

    2014-03-01

    Full Text Available The idea of a bioactive surface coating that enhances bone healing and bone growth is a strong focus of on-going research for bone implant materials. Enamel matrix derivate (EMD is well documented to support bone regeneration and activates growth of mesenchymal tissues. Thus, it is a prime candidate for coating of existing implant surfaces. The aim of this study was to show that cathodic polarization can be used for coating commercially available implant surfaces with an immobilized but functional and bio-available surface layer of EMD. After coating, XPS revealed EMD-related bindings on the surface while SIMS showed incorporation of EMD into the surface. The hydride layer of the original surface could be activated for coating in an integrated one-step process that did not require any pre-treatment of the surface. SEM images showed nano-spheres and nano-rods on coated surfaces that were EMD-related. Moreover, the surface roughness remained unchanged after coating, as it was shown by optical profilometry. The mass peaks observed in the matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS analysis confirmed the integrity of EMD after coating. Assessment of the bioavailability suggested that the modified surfaces were active for osteoblast like MC3M3-E1 cells in showing enhanced Coll-1 gene expression and ALP activity.

  7. Surface studies of barium and barium oxide on tungsten and its application to understanding the mechanism of operation of an impregnated tungsten cathode

    Science.gov (United States)

    Forman, R.

    1976-01-01

    Surface studies have been made of multilayer and monolayer films of barium and barium oxide on a tungsten substrate. The purpose of the investigation was to synthesize the surface conditions that exist on an activated impregnated tungsten cathode and obtain a better understanding of the mechanism of operation of such cathodes. The techniques employed in these measurements were Auger spectroscopy and work-function measurements. The results of this study show that the surface of an impregnated cathode is identical to that observed for a synthesized monolayer or partial monolayer of barium on oxidized tungsten by evaluating Auger spectra and work-function measurements. Data obtained from desorption studies of barium monolayers on a tungsten substrate in conjunction with Auger and work-function results have been interpreted to show that throughout most of its life an impreganated cathode has a partial monolayer, rather than a monolayer, of barium on its surface.

  8. Improve electrochemical performance of CeO2 surface modification LiNi0.80Co0.15Al0.05O2 cathode material

    Science.gov (United States)

    Xia, Shubiao; Zhang, Yingjie; Dong, Peng; Zhang, Yannan

    2014-06-01

    Lithium ion battery cathode material LiNi0.8Co0.15Al0.05O2 cathode has successfully prepared by co-precipitation. CeO2 surface modification has improved LiNi0.80Co0.15Al0.05O2 electrochemical performance use sol-gel method and subsequent heat treatment at 600 °C for 5 h. Different to other conventional coating material, CeO2 coating layer can not only inhibit the reaction of the electrode and the electrolyte, but also can reduce the impedance of electron transfer due to its high conductivity, and inhibit the production of Ni2+ because of its high oxidation. The surface-modified and pristine LiNi0.80Co0.15Al0.05O2 powders are characterized by XRD, SEM, TEM, XPS, CV and DSC. When CeO2 coating is 0.02% (mole ratio), contrast to pristine NCA, the CeO2-coated NCA cathode exhibits no decrease in its initial specific capacity of 184 mAh g -1 (at 0.2 C) and excellent capacity retention (86% of its initial capacity at 1 C) between 2.75 and 4.3 V after 100 cycles. The results indicate that the CeO2 surface treatment should be an effective way to improve cycle properties due to CeO2 inhibit the electrodes and the electrolyte side effects.

  9. Carbon black as an alternative cathode material for electrical energy recovery and transfer in a microbial battery.

    Science.gov (United States)

    Zhang, Xueqin; Guo, Kun; Shen, Dongsheng; Feng, Huajun; Wang, Meizhen; Zhou, Yuyang; Jia, Yufeng; Liang, Yuxiang; Zhou, Mengjiao

    2017-08-01

    Rather than the conventional concept of viewing conductive carbon black (CB) to be chemically inert in microbial electrochemical cells (MECs), here we confirmed the redox activity of CB for its feasibility as an electron sink in the microbial battery (MB). Acting as the cathode of a MB, the solid-state CB electrode showed the highest electron capacity equivalent of 18.58 ± 0.46 C/g for the unsintered one and the lowest capacity of 2.29 ± 0.48 C/g for the one sintered under 100% N 2 atmosphere. The capacity vibrations of CBs were strongly in coincidence with the abundances of C=O moiety caused by different pretreatments and it implied one plausible mechanism based on CB's surface functionality for its electron capturing. Once subjected to electron saturation, CB could be completely regenerated by different strategies in terms of electrochemical discharging or donating electrons to biologically-catalyzed nitrate reduction. Surface characterization also revealed that CB's regeneration fully depended on the reversible shift of C=O moiety, further confirming the functionality-based mechanism for CB's feasibility as the role of MB's cathode. Moreover, resilience tests demonstrated that CB cathode was robust for the multi-cycles charging-discharging operations. These results imply that CB is a promising alternative material for the solid-state cathode in MBs.

  10. Doping Li-rich cathode material Li2MnO3 : Interplay between lattice site preference, electronic structure, and delithiation mechanism

    Science.gov (United States)

    Hoang, Khang

    2017-12-01

    We report a detailed first-principles study of doping in Li2MnO3 , in both the dilute doping limit and heavy doping, using hybrid density-functional calculations. We find that Al, Fe, Mo, and Ru impurities are energetically most favorable when incorporated into Li2MnO3 at the Mn site, whereas Mg is most favorable when doped at the Li sites. Nickel, on the other hand, can be incorporated at the Li site and/or the Mn site, and the distribution of Ni over the lattice sites can be tuned by tuning the material preparation conditions. There is a strong interplay among the lattice site preference and charge and spin states of the dopant, the electronic structure of the doped material, and the delithiation mechanism. The calculated electronic structure and voltage profile indicate that in Ni-, Mo-, or Ru-doped Li2MnO3 , oxidation occurs on the electrochemically active transition-metal ion(s) before it does on oxygen during the delithiation process. The role of the dopants is to provide charge compensation and bulk electronic conduction mechanisms in the initial stages of delithiation, hence enabling the oxidation of the lattice oxygen in the later stages. This work thus illustrates how the oxygen-oxidation mechanism can be used in combination with the conventional mechanism involving transition-metal cations in design of high-capacity battery cathode materials.

  11. Marine microbial fuel cell: Use of stainless steel electrodes as anode and cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Dumas, C.; Basseguy, R.; Etcheverry, L.; Bergel, A. [Laboratoire de Genie Chimique, CNRS-INPT, Toulouse Cedex (France); Mollica, A. [CNR-ISMAR, Genoa (Italy); Feron, D. [SCCME, CEA Saclay, Gif-sur-Yvette (France)

    2007-12-01

    Numerous biocorrosion studies have stated that biofilms formed in aerobic seawater induce an efficient catalysis of the oxygen reduction on stainless steels. This property was implemented here for the first time in a marine microbial fuel cell (MFC). A prototype was designed with a stainless steel anode embedded in marine sediments coupled to a stainless steel cathode in the overlying seawater. Recording current/potential curves during the progress of the experiment confirmed that the cathode progressively acquired effective catalytic properties. The maximal power density produced of 4 mW m{sup -2} was lower than those reported previously with marine MFC using graphite electrodes. Decoupling anode and cathode showed that the cathode suffered practical problems related to implementation in the sea, which may found easy technical solutions. A laboratory fuel cell based on the same principle demonstrated that the biofilm-covered stainless steel cathode was able to supply current density up to 140 mA m{sup -2} at +0.05 V versus Ag/AgCl. The power density of 23 mW m{sup -2} was in this case limited by the anode. These first tests presented the biofilm-covered stainless steel cathodes as very promising candidates to be implemented in marine MFC. The suitability of stainless steel as anode has to be further investigated. (author)

  12. Comparative study on experiments and simulation of blended cathode active materials for lithium ion batteries

    International Nuclear Information System (INIS)

    Appiah, Williams Agyei; Park, Joonam; Van Khue, Luu; Lee, Yunju; Choi, Jaecheol; Ryou, Myung-Hyun; Lee, Yong Min

    2016-01-01

    We simulate the electrochemical properties of Li-ion cells consisting of a blended cathode composed of LiMn 2 O 4 and LiNi 0.6 Co 0.2 Mn 0.2 O 2 and an artificial graphite anode using the Li-ion battery model available in COMSOL MULTIPHYSICS 4.4 along with a capacity fade model. The discharge profiles of the pure and blended cathodes at various current rates obtained through simulations and experimental results are well matched. By combining two capacity fade models available in literature, namely the solid electrolyte interphase (SEI) growth model and the Mn 2+ dissolution model, the cycling performance of the pure LiMn 2 O 4 cells at 25 °C are successfully simulated and found to be in a good agreement with the experimental results. The blended cathode exhibits better capacity retention than the pure LiMn 2 O 4 during cycling. We also observed that at high powers, the gravimetric energy density of the LiMn 2 O 4 cathode exceeds that of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode; the reverse effect is seen at low powers. Further, we were able to easily modulate the energy and power densities of the blended cathode system by changing the blend ratio in our simulation model.

  13. Modeling and Predicting the Electrical Conductivity of Composite Cathode for Solid Oxide Fuel Cell by Using Support Vector Regression

    Science.gov (United States)

    Tang, J. L.; Cai, C. Z.; Xiao, T. T.; Huang, S. J.

    2012-07-01

    The electrical conductivity of solid oxide fuel cell (SOFC) cathode is one of the most important indices affecting the efficiency of SOFC. In order to improve the performance of fuel cell system, it is advantageous to have accurate model with which one can predict the electrical conductivity. In this paper, a model utilizing support vector regression (SVR) approach combined with particle swarm optimization (PSO) algorithm for its parameter optimization was established to modeling and predicting the electrical conductivity of Ba0.5Sr0.5Co0.8Fe0.2 O3-δ-xSm0.5Sr0.5CoO3-δ (BSCF-xSSC) composite cathode under two influence factors, including operating temperature (T) and SSC content (x) in BSCF-xSSC composite cathode. The leave-one-out cross validation (LOOCV) test result by SVR strongly supports that the generalization ability of SVR model is high enough. The absolute percentage error (APE) of 27 samples does not exceed 0.05%. The mean absolute percentage error (MAPE) of all 30 samples is only 0.09% and the correlation coefficient (R2) as high as 0.999. This investigation suggests that the hybrid PSO-SVR approach may be not only a promising and practical methodology to simulate the properties of fuel cell system, but also a powerful tool to be used for optimal designing or controlling the operating process of a SOFC system.

  14. The impact of new cathode materials relative to baseline performance of microbial fuel cells all with the same architecture and solution chemistry

    KAUST Repository

    Yang, Wulin

    2017-04-21

    Differences in microbial fuel cell (MFC) architectures, materials, and solution chemistries, have previously hindered direct comparisons of improvements in power production due to new cathode materials. However, one common reactor design has now been used in many different laboratories around the world under similar operating conditions based on using: a graphite fiber brush anode, a platinum cathode catalyst, a single-chamber cube-shaped (4-cm) MFC with a 3-cm diameter anolyte chamber, 50 mM phosphate buffer, and an acetate fuel. Analysis of several publications over 10 years from a single laboratory showed that even under such identical operational conditions, maximum power densities varied by 15%, with an average of 1.36 ± 0.20 W m–2 (n=24), normalized to cathode projected area (34 W m–3 liquid volume). In other laboratories, maximum power was significantly less, with an average of 1.03 ± 0.46 W m–2 (n=11), despite identical conditions. One likely reason for the differences in power is cathode age. Power production with Pt catalyst cathodes significantly declined after one month of operation or more to 0.87 ± 0.31 W m–2 (n=18) based on studies where cathode aging was examined, while in many studies the age of the cathode was not reported. Using these studies as a performance baseline, we review the claims of improvements in power generation due to new anode or cathode materials, or changes in solution conductivities and substrates.

  15. Synthesis and characterization of LiFePO4/C cathode materials by sol-gel method.

    Science.gov (United States)

    Liu, Shuxin; Yin, Hengbo; Wang, Haibin; Wang, Hong

    2014-09-01

    The carbon coated LiFePO4 cathode materials (LiFePO4/C) were successfully synthesized by sol-gel method with glucose, citric acid and PEG-4000 as dispersant and carbon source, respectively. The microstructure and grain size of LiFePO4/C composite were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy. The results showed that the carbon source and calcination temperature had important effect on the graphitization degree of carbon; the carbon decomposed by citric acid had higher graphitization degree; with calcination temperature rising, the graphitization degree of carbon increased and the particles size increased. The graphitization degree and grain size were very important for improving the electrochemical performance of LiFePO4 cathode materials, according to the experimental results, the sample LFP-700 (LFP-C) which was synthesized with citric acid as dispersant at 700 degree C had lower polarization and larger discharge capacity.

  16. Preparation and characterization of SnO2 and Carbon Co-coated LiFePO4 cathode materials.

    Science.gov (United States)

    Wang, Haibin; Liu, Shuxin; Huang, Yongmao

    2014-04-01

    The SnO2 and carbon co-coated LiFePO4 cathode materials were successfully synthesized by solid state method. The microstructure and morphology of LiFePO4 composites were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscope. The results showed that the SnO2 and carbon co-coated LiFePO4 cathode materials exhibited more uniform particle size distribution. Compared with the uncoated LiFePO4/C, the structure of LiFePO4 with SnO2 and carbon coating had no change. The existence of SnO2 and carbon coating layer effectively enhanced the initial discharge capacity. Among the investigated samples, the one with DBTDL:LiFePO4 molar ratios of 7:100 exhibited the best electrochemical performance.

  17. Electrochemical reduction of oxygen and nitric oxide at low temperature on Ce1−xPrxO2−δ cathodes

    DEFF Research Database (Denmark)

    Werchmeister, Rebecka Maria Larsen; Kammer Hansen, Kent

    2013-01-01

    The ability of praseodymium doped cerium oxide materials to electrochemically reduce NO and O2 was studied using cone-shaped electrodes in conjunction with cyclic voltammetry, in the temperature range 200–400 °C. Four samples were studied; Ce1−xPrxO2−δ (x = 0.1, 0.2, 0.3 and 0.4). It was shown...... the highest ratio of maximum cathodic current density (iNO/iO2iNO/iO2), which is used as an indication of a higher activity toward reduction of NO compared to reduction of O2. The apparent selectivity generally decreased with increasing temperature for all the compositions....

  18. Multielectronic conduction in La1-xSrxGa1/2Mn1/2O3-δ as solid oxide fuel cell cathode

    Science.gov (United States)

    Iguchi, E.; Hashimoto, Y.; Kurumada, M.; Munakata, F.

    2003-08-01

    Four-probe dc conductivities, capacitances, and thermopower have been measured in the temperature range of 80-1123 K for La1-xSrxGa1/2Mn1/2O3-δ, which is a desirable cathode material for lanthanum-gallate electrolytes of solid oxide fuel cells. The dc conductivities in the specimens (0.1⩽x⩽0.3) are insensitive to x but the thermopower is very sensitive to x, although the x=0 specimen exhibits a somewhat different conduction behavior. At T500 K, the band conduction dominates the electronic transports. The ionic conduction due to O2- migration seems difficult to contribute directly to the dc conduction even at high temperature.

  19. Improved performance of LaNi0.6Fe0.4O3 solid oxide fuel cell cathode by application of a thin interface cathode functional layer

    DEFF Research Database (Denmark)

    Molin, Sebastian; Jasinski, Piotr Z.

    2017-01-01

    In this work, novel functional layers were prepared by a low temperature spray pyrolysis method on the oxygen side of the solid oxide cells. Thin layers of Ce0.8Gd0.2O2 and LaNi0.6Fe0.4O3 are prepared between the electrolyte and the porous oxygen electrode. Additionally the influence of the sprayed...... ceria barrier layer on the zirconia based electrolyte with the new layers is evaluated. Impedance spectroscopy results show improvement in contact between the electrolyte and the porous cathode electrode. Additionally, electrochemical performance of the cathode is improved, as evidenced by a lowered...

  20. Synthesis and Electrochemical Performance of LixMn2-yCoyO4-dCld Cathode Material

    Science.gov (United States)

    2016-06-13

    Synthesis and Electrochemical Performance of LixMn2-yCoyO4-dCld Cathode Material Terrill B. Atwater, Paula C. Latorre, and Ashley L. Ruth U.S...low toxicity, comparable capacity, and low cost. However, this spinel suffers from capacity fading due to fracturing of the cell structure...dopants of interest include compounds containing Group VIII Row 4 (Fe, Co, and Ni) elements, cobalt in particular. In addition to fabrication method

  1. La{sub 0.84}Sr{sub 0.16}MnO{sub 3-{delta}} cathodes impregnated with Bi{sub 1.4}Er{sub 0.6}O{sub 3} for intermediate-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Junliang; Wang, Shaorong; Wang, Zhenrong; Liu, Renzhu; Wen, Tinglian; Wen, Zhaoyin [The Key Laboratory of Energy Conversion Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2009-12-01

    La{sub 0.84}Sr{sub 0.16}MnO{sub 3-{delta}}-Bi{sub 1.4}Er{sub 0.6}O{sub 3} (LSM-ESB) composite cathodes are fabricated by impregnating LSM electronic conducting matrix with the ion-conducting ESB for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The performance of LSM-ESB cathodes is investigated at temperatures below 750 C by AC impedance spectroscopy. The ion-impregnation of ESB significantly enhances the electrocatalytic activity of the LSM electrodes for the oxygen reduction reactions, and the ion-impregnated LSM-ESB composite cathodes show excellent performance. At 750 C, the value of the cathode polarization resistance (R{sub p}) is only 0.11 {omega} cm{sup 2} for an ion-impregnated LSM-ESB cathode, which also shows high stability during a period of 200 h. For the performance testing of single cells, the maximum power density is 0.74 W cm{sup -2} at 700 C for a cell with the LSM-ESB cathode. The results demonstrate the ion-impregnated LSM-ESB is one of the promising cathode materials for intermediate-temperature solid oxide fuel cells. (author)

  2. Cathode material and pulsed plasma treatment influence on the microstructure and microhardness of high-chromium cast iron surface

    Directory of Open Access Journals (Sweden)

    Юлія Геннадіївна Чабак

    2016-11-01

    Full Text Available The article presents an analysis of the cathode material and the pulse plasma treatment mode influence on the surface microstructure and microhardness of high chrome (15% Cr cast iron. The methods of metallographic analysis and microhardness measurements were used. It has been shown that pulsed plasma treatment at 4 kV voltage with the use of the electro-axial thermal accelerator results in surface modification with high microhardness 950-1050 HV50, and in the formation of the coating due to the transfer of the electrodes material. The specific features of using different cathode materials have been systematized. It has been found that graphite electrodes are not recommended to be used due to their low strength and fracture under plasma pulses. In case of using tungsten cathode a coating of small thickness (20-30 microns and having cracks has been formed on the specimen surface. The most expedient is to apply the electrodes with low melting point (such as killed St.3, which provides a high-quality state of treated surface and formation the protective crack-free coating of 80-100 microns thick. It has been found that as a result of the plasma pulsed treatment the enrichment of coating with carbon is likely to occur that results in microhardness increase. The prospects of this technology as well as its shortcomings have been described

  3. TH-CD-207B-01: BEST IN PHYSICS (IMAGING): Development of High Brightness Multiple-Pixel X-Ray Source Using Oxide Coated Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Kandlakunta, P; Pham, R; Zhang, T [Washington University School of Medicine, St. Louis, MO (United States)

    2016-06-15

    Purpose: To develop and characterize a high brightness multiple-pixel thermionic emission x-ray (MPTEX) source. Methods: Multiple-pixel x-ray sources allow for designs of novel x-ray imaging techniques, such as fixed gantry CT, digital tomosynthesis, tetrahedron beam computed tomography, etc. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide coated cathodes. Oxide cathode is chosen as the electron source due to its high emission current density and low operating temperature. A MPTEX prototype has been developed which may contain up to 41 micro-rectangular oxide cathodes in 4 mm pixel spacing. Electronics hardware was developed for source control and switching. The cathode emission current was evaluated and x-ray measurements were performed to estimate the focal spot size. Results: The oxide cathodes were able to produce ∼110 mA cathode current in pulse mode which corresponds to an emission current density of 0.55 A/cm{sup 2}. The maximum kVp of the MPTEX prototype currently is limited to 100 kV due to the rating of high voltage feedthrough. Preliminary x-ray measurements estimated the focal spot size as 1.5 × 1.3 mm{sup 2}. Conclusion: A MPTEX source was developed with thermionic oxide coated cathodes and preliminary source characterization was successfully performed. The MPTEX source is able to produce an array of high brightness x-ray beams with a fast switching speed.

  4. Hydrothermal synthesis and characterization of novel vanadium oxides and their application as cathodes in lithium secondary batteries

    Science.gov (United States)

    Chirayil, Thomas George

    Novel layered or tunneled vanadium oxides are sought as a substitute for the expensive Lisb{x}CoOsb2 cathode material in lithium rechargeable batteries. The hydrothermal synthesis approach was taken in search of new vanadium oxides in the presence of a structure directing cation, TMA. A systematic study was done on the hydrothermal synthesis of the Vsb{2}Osb{5}-TMAOH-LiOH system. It was determined from this study that the pH of the reaction mixture was very critical in the formation of many compounds. Acetic acid utilized to adjust the pH of the reaction mixture in the presence of TMA behaved as a buffer and maintained a constant pH during the reaction. Hydrothermal synthesis conducted between pH 10 and 2 resulted in the formation of 7 compounds. At the highest pH, a well known compound Lisb3VOsb4, was formed. Between pH 5.2-9, a layered compound, TMAVsb3Osb7 resulted. The thermal treatment of TMAVsb3Osb7 under oxygen lead to an oxidized phase, TMAVsb3Osb8, which increased its lithium capacity significantly. Between pH 5-6, a cluster compound, TMAsb8lbrack Vsb{22}Osb{54}(CHsb3COO)rbrack{*}4Hsb2O with the acetate ion trapped inside the caged Vsb{22}Osb{54} cluster, and a layered vanadium oxide, Lisb{x}Vsb{2-delta}Osb{4-delta}{*}Hsb2O was obtained. The Lisb{x}Vsb{2-delta}Osb{4-delta}{*}Hsb2O compound was dehydrated to form Lisb{x}Vsb{2-delta}Osb{4-delta} and the lithium was removed electrochemically to form a new type of "VOsb2". Several alkylamines, DMSO and an additional water molecule were intercalated to swell the layers of Lisb{x}Vsb{2-delta}Osb{4-delta}{*}Hsb2O. Lowering the pH between 3.0-3.5, resulted in layered compound, TMAVsb4Osb{10}, with TMA residing between the layers. Layered compounds, TMAVsb8Osb{20} and TMAsb{0.17}Hsp+sb{0.1}Vsb2Osb5, were obtained at very acidic conditions. The hydrothermally grown TMAsb{0.17}Hsp+sb{0.1}Vsb2Osb5 is similar to the xerogel Vsb2Osb5 intercalated with TMA synthesized by the sol-gel process. Several trends were observed

  5. Quantifying the environmental impact of a Li-rich high-capacity cathode material in electric vehicles via life cycle assessment.

    Science.gov (United States)

    Wang, Yuqi; Yu, Yajuan; Huang, Kai; Chen, Bo; Deng, Wensheng; Yao, Ying

    2017-01-01

    A promising Li-rich high-capacity cathode material (xLi 2 MnO 3 ·(1-x)LiMn 0.5 Ni 0.5 O 2 ) has received much attention with regard to improving the performance of lithium-ion batteries in electric vehicles. This study presents an environmental impact evaluation of a lithium-ion battery with Li-rich materials used in an electric vehicle throughout the life cycle of the battery. A comparison between this cathode material and a Li-ion cathode material containing cobalt was compiled in this study. The battery use stage was found to play a large role in the total environmental impact and high greenhouse gas emissions. During battery production, cathode material manufacturing has the highest environmental impact due to its complex processing and variety of raw materials. Compared to the cathode with cobalt, the Li-rich material generates fewer impacts in terms of human health and ecosystem quality. Through the life cycle assessment (LCA) results and sensitivity analysis, we found that the electricity mix and energy efficiency significantly influence the environmental impacts of both battery production and battery use. This paper also provides a detailed life cycle inventory, including firsthand data on lithium-ion batteries with Li-rich cathode materials.

  6. Oxidation rate in ferritic superheater materials

    International Nuclear Information System (INIS)

    Falk, I.

    1992-05-01

    On the steam side of superheater tubes, compact oxide layers are formed which have a tendency to crack and flake off (exfoliate). Oxide particles then travel with the steam and can give rise to erosion damage in valves and on turbine blades. In an evaluation of conditions in superheater tubes from Swedish power boilers, it was found that the exfoliation frequency for one material quality (SS 2218) was greater than for other qualities. Against this background, a literature study has been carried out in order to determine which mechanisms govern the build-up of oxide and the exfoliation phenomenon. The study reveals that the oxide morphology is similar on all ferritic steels with Cr contents up to 5%. and that the oxide properties can therefore be expected to be similar. The reason why the exfoliation frequency is greater for tubes of SS 2218 is probably that the tubes have been exposed to higher temperatures. SS 2218 (2.25 Cr) is normally used in a higher temperature range which is accompanied by improved strength data as compared with SS 2216 (1 Cr). The principal cause of the exfoliation is said to be stresses which arise in the oxide during the cooling-down process associated with shutdowns. The stresses give rise to longitudinal cracks in the oxide, and are formed as a result of differences in thermal expansion between the oxide and the tube material. In addition, accounts are presented of oxidation constants and growth velocities, and thickness and running time. These data constitute a valuable basis for practical estimates of the operating temperature in routine checks and investigations into damage in superheater tubes. (au)

  7. Microstructure development in zinc oxide nanowires and iron oxohydroxide nanotubes by cathodic electrodeposition in nanopores

    NARCIS (Netherlands)

    Maas, M.G.; Rodijk, E.J.B.; Maijenburg, A.W.; Blank, David H.A.; ten Elshof, Johan E.

    2011-01-01

    The cathodic electrodeposition of crystalline ZnO nanowires and amorphous FeO(OH) nanotubes in polycarbonate track-etched membranes with pore diameters of 50–200 nm is reported. Nitrate was used as a sacrificial precursor for the electrochemical generation of hydroxyl ions that raised the pH of the

  8. Study of the Durability of Doped Lanthanum Manganite and Cobaltite Cathode Materials under ''Real World'' Air Exposure Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Prabhakar [Univ. of Connecticut, Storrs, CT (United States); Mahapatra, Manoj [Univ. of Connecticut, Storrs, CT (United States); Ramprasad, Rampi [Univ. of Connecticut, Storrs, CT (United States); Minh, Nguyen [Univ. of California, San Diego, CA (United States); Misture, Scott [Alfred Univ., NY (United States)

    2014-11-30

    The overall objective of the program is to develop and validate mechanisms responsible for the overall structural and chemical degradation of lanthanum manganite as well as lanthanum ferrite cobaltite based cathode when exposed to “real world” air atmosphere exposure conditions during SOFC systems operation. Of particular interest are the evaluation and analysis of degradation phenomena related to and responsible for (a) products formation and interactions with air contaminants, (b) dopant segregation and oxide exolution at free surfaces, (c) cation interdiffusion and reaction products formation at the buried interfaces, (d) interface morphology changes, lattice transformation and the development of interfacial porosity and (e) micro-cracking and delamination from the stack repeat units. Reaction processes have been studied using electrochemical and high temperature materials compatibility tests followed by structural and chemical characterization. Degradation hypothesis has been proposed and validated through further experimentation and computational simulation.

  9. Oxide bipolar electronics: materials, devices and circuits

    International Nuclear Information System (INIS)

    Grundmann, Marius; Klüpfel, Fabian; Karsthof, Robert; Schlupp, Peter; Schein, Friedrich-Leonhard; Splith, Daniel; Yang, Chang; Bitter, Sofie; Von Wenckstern, Holger

    2016-01-01

    We present the history of, and the latest progress in, the field of bipolar oxide thin film devices. As such we consider primarily pn-junctions in which at least one of the materials is a metal oxide semiconductor. A wide range of n-type and p-type oxides has been explored for the formation of such bipolar diodes. Since most oxide semiconductors are unipolar, challenges and opportunities exist with regard to the formation of heterojunction diodes and band lineups. Recently, various approaches have led to devices with high rectification, namely p-type ZnCo 2 O 4 and NiO on n-type ZnO and amorphous zinc-tin-oxide. Subsequent bipolar devices and applications such as photodetectors, solar cells, junction field-effect transistors and integrated circuits like inverters and ring oscillators are discussed. The tremendous progress shows that bipolar oxide electronics has evolved from the exploration of various materials and heterostructures to the demonstration of functioning integrated circuits. Therefore a viable, facile and high performance technology is ready for further exploitation and performance optimization. (topical review)

  10. High insulation foam glass material from waste cathode ray tube panel glass

    DEFF Research Database (Denmark)

    König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

    . In general CRT consists of two types of glasses: barium/strontium containing glass (panel glass) and lead containing glass (funnel and panel glass). In this work we present the possibility to produce high performance insulation material from the recycled lead-free glass. We studied the influence of foaming...... between 750 and 850°C. We investigated the influence of milling time, particle size, foaming and oxidizing agent concentrations, temperature and time on the foaming process, foam density, foam porosity and homogeneity. Only moderate foaming was observed in carbon containing samples, while the addition...... of the oxidizing agent greatly improved the foaming quality. The results showed that the amount of oxygen available from the glass is not sufficient to combust all of the added carbon, therefore, additional oxygen was supplied via manganese reduction. In general, a minimum in the foam glass density was observed...

  11. Design of high-performance cathode materials with single-phase pathway for sodium ion batteries: A study on P2-Nax(LiyMn1-y)O2 compounds

    Science.gov (United States)

    Yang, Lufeng; Li, Xiang; Ma, Xuetian; Xiong, Shan; Liu, Pan; Tang, Yuanzhi; Cheng, Shuang; Hu, Yan-Yan; Liu, Meilin; Chen, Hailong

    2018-03-01

    Sodium-ion batteries (SIBs) are an emerging electrochemical energy storage technology that has high promise for electrical grid level energy storage. High capacity, long cycle life, and low cost cathode materials are very much desired for the development of high performance SIB systems. Sodium manganese oxides with different compositions and crystal structures have attracted much attention because of their high capacity and low cost. Here we report our investigations into a group of promising lithium doped sodium manganese oxide cathode materials with exceptionally high initial capacity of ∼223 mAh g-1 and excellent capacity retentions, attributed primarily to the absence of phase transformation in a wide potential range of electrochemical cycling, as confirmed by in-operando X-ray diffraction (XRD), Rietveld refinement, and high-resolution 7Li solid-state NMR characterizations. The systematic study of structural evolution and the correlation with the electrochemical behavior of the doped cathode materials provides new insights into rational design of high-performance intercalation compounds by tailoring the composition and the crystal structure evolution in electrochemical cycling.

  12. Hierarchical porous nickel oxide-carbon nanotubes as advanced pseudocapacitor materials for supercapacitors

    Science.gov (United States)

    Su, Aldwin D.; Zhang, Xiang; Rinaldi, Ali; Nguyen, Son T.; Liu, Huihui; Lei, Zhibin; Lu, Li; Duong, Hai M.

    2013-03-01

    Hierarchical porous carbon anode and metal oxide cathode are promising for supercapacitor with both high energy density and high power density. This Letter uses NiO and commercial carbon nanotubes (CNTs) as electrode materials for electrochemical capacitors with high energy storage capacities. Experimental results show that the specific capacitance of the electrode materials for 10%, 30% and 50% CNTs are 279, 242 and 112 F/g, respectively in an aqueous 1 M KOH electrolyte at a charge rate of 0.56 A/g. The maximum specific capacitance is 328 F/g at a charge rate of 0.33 A/g.

  13. Fe-N-C catalyst modified graphene sponge as a cathode material for lithium-oxygen battery

    International Nuclear Information System (INIS)

    Yu, Ling; Shen, Yue; Huang, Yunhui

    2014-01-01

    Highlights: • Hydrothermally-synthesized graphene sponge is excellent skeleton of Li-O 2 cathode. • Fe-N-C catalyst loaded on GS was attained via pyrolysis of FePc and GS composites. • High capacity and good cyclability were achieved with Fe-N-GS air electrode. • The synergy of porous structure and catalytic activity leads to the high performance. - Abstract: The cathode of a lithium-oxygen battery needs the synergism of a porous conducting material and a catalyst to facilitate the formation and decomposition of lithium peroxide. Here we introduce a graphene sponge (GS) modified with Fe-N-C catalyst for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). The porous, 3-dimensional conductive and free standing nature of the graphene sponge makes it become excellent skeleton of cathode for lithium-oxygen battery. The Fe-N-C catalyst nanoparticles dispersed uniformly on the graphene sheets show excellent catalytic reactivity in both discharge and charge processes. This kind of composite material greatly improves the capacity and cyclability of the lithium-oxygen battery. With dimethyl sulphoxide as electrolyte, the capacity reaches 6762 mAh g −1 which is twice of the pure graphene sponge. In addition, the cell containing Fe-N-GS air electrode exhibits stable cyclic performance and effective reduction of charge potential plateau, indicating that Fe-N-GS is promising as an OER catalyst in rechargeable lithium-air batteries

  14. Preparation of oxide materials from metal alkoxides

    International Nuclear Information System (INIS)

    Turevskaya, E.P.; Turova, N.Ya.; Yanovskaya, M.I.

    2000-01-01

    The results of studies on the sol-gel technologies on the basis of alkoxides are presented. The synthesis and properties of titanates zirconates, niobates, tantalates, vanadates and solid solutions on the basis of Mo, W and Bi oxides, iron oxides and high-temperature superconductors are presented. The most important aspects, determining the choice of optimal conditions for preparation of oxides of concrete compositions with required properties are pointed out. Accomplishment of the whole chain of studies made it possible to synthesize a broad range of metal alkoxides and study their properties and also carry out large-scale studies on preparation of various oxides and materials on the basis thereof, using the source base of the sol-gel method [ru

  15. Binder materials for the cathodes applied to self-stratifying membraneless microbial fuel cell.

    Science.gov (United States)

    Walter, Xavier Alexis; Greenman, John; Ieropoulos, Ioannis

    2018-04-19

    The recently developed self-stratifying membraneless microbial fuel cell (SSM-MFC) has been shown as a promising concept for urine treatment. The first prototypes employed cathodes made of activated carbon (AC) and polytetrafluoroethylene (PTFE) mixture. Here, we explored the possibility to substitute PTFE with either polyvinyl-alcohol (PVA) or PlastiDip (CPD; i.e. synthetic rubber) as binder for AC-based cathode in SSM-MFC. Sintered activated carbon (SAC) was also tested due to its ease of manufacturing and the fact that no stainless steel collector is needed. Results indicate that the SSM-MFC having PTFE cathodes were the most powerful measuring 1617 μW (11 W·m -3 or 101 mW·m -2 ). SSM-MFC with PVA and CPD as binders were producing on average the same level of power (1226 ± 90 μW), which was 24% less than the SSM-MFC having PTFE-based cathodes. When balancing the power by the cost and environmental impact, results clearly show that PVA was the best alternative. Power wise, the SAC cathodes were shown being the less performing (≈1070 μW). Nonetheless, the lower power of SAC was balanced by its inexpensiveness. Overall results indicate that (i) PTFE is yet the best binder to employ, and (ii) SAC and PVA-based cathodes are promising alternatives that would benefit from further improvements. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Thermodynamic and exergoeconomic analysis of biogas fed solid oxide fuel cell power plants emphasizing on anode and cathode recycling: A comparative study

    International Nuclear Information System (INIS)

    Mehr, A.S.; Mahmoudi, S.M.S.; Yari, M.; Chitsaz, A.

    2015-01-01

    Highlights: • Four biogas-fed solid oxide fuel cell power plants are proposed. • Performance of systems is compared with each other economically. • Efficiency of biogas fed fuel cell with anode–cathode recycling is the highest. • For current density of 6000 A/m"2 the optimum anode recycle ratio is around 0.25. • Unit product cost of biogas fed fuel cell with anode–cathode recycling is 19.07$/GJ. - Abstract: Four different configurations of natural gas and biogas fed solid oxide fuel cell are proposed and analyzed thermoeconomically, focusing on the influence of anode and/or cathode gas recycling. It is observed that the net output power is maximized at an optimum current density the value of which is lowered as the methane concentration in the biogas is decreased. Results indicate that when the current density is low, there is an optimum anode recycling ratio at which the thermal efficiency is maximized. In addition, an increase in the anode recycling ratio increases the unit product cost of the system while an increase in the cathode recycling ratio has a revers effect. For the same working conditions, the solid oxide fuel cell with anode and cathode recycling is superior to the other configurations and its thermal efficiency is calculated as 46.09% being 6.81% higher than that of the simple solid oxide fuel cell fed by natural gas. The unit product cost of the solid oxide fuel cell-anode and cathode recycling system is calculated as 19.07$/GJ which is about 35% lower than the corresponding value for the simple natural gas fed solid oxide fuel cell system.

  17. Composite cathode La0.15Bi0.85O1.5-Ag for intermediate-temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Gao Zhan; Mao Zongqiang; Huang Jianbing; Gao Ruifeng; Wang Cheng; Liu Zhixiang

    2008-01-01

    Composites consisting of silver and lanthanum stabilized bismuth oxide (La 0.15 Bi 0.85 O 1.5 ) were investigated as cathodes for intermediate-temperature solid oxide fuel cells with doped ceria as electrolyte. No stable phases were formed via reaction between La 0.15 Bi 0.85 O 1.5 and Ag. The microstructure of the interfaces between composite cathodes and Ce 0.8 Sm 0.2 O 1.5 electrolytes was studied by scanning electron microscopy after sintering at various temperatures. Impedance spectroscopy measurements revealed that the performance of cathode fired at 700 deg. C was the best. When the optimum fraction of Ag was 50 vol.%, polarization resistance values for the LSB-Ag50 cathode were as low as 0.14 Ω cm 2 at 700 deg. C and 0.18 Ω cm 2 at 650 deg. C. The steady-state polarization investigations on LSB and LSB-Ag50 cathodes were performed using typical three-electrode test cells in air. The results showed that the LSB-Ag50 composite cathode exhibited a lower overpotential and higher exchange current density than LSB, which indicated the electrochemical performance of LSB-Ag50 for the oxygen reduction reaction was superior to the LSB

  18. Structural characterization of layered Na0.5Co0.5Mn0.5O2 material as a promising cathode for sodium-ion batteries

    Science.gov (United States)

    Manikandan, Palanisamy; Heo, Seongwoo; Kim, Hyun Woo; Jeong, Hu Young; Lee, Eungje; Kim, Youngsik

    2017-09-01

    Layered Na0.5Co0.5Mn0.5O2 material is synthesized through a facile mixed hydroxy-carbonate route using (Co0.5Mn0.5)2(OH)2CO3 precursor and well characterized as a hexagonal layered structure under P63/mmc space group. The lattice parameters and unit cell volume (a = 2.8363 Å, c = 11.3152 Å and V = 78.83 Å3) are calculated by Rietveld refinement analysis. A flaky-bundle morphology is obtained to the layered Na0.5Co0.5Mn0.5O2 material with the hexagonal flake size ∼30 nm. Advanced transmission electron microscopic images are revealed the local structure of the layered Na0.5Co0.5Mn0.5O2 material with contrasting bright dots and faint dark dots corresponding to the Co/Mn and Na atoms. Two oxidation and reduction peaks are occurred in a cyclic voltammetric analysis corresponding to Co3+/Co4+ and Mn3+/Mn4+ redox processes. These reversible processes are attributed to the intercalation/de-intercalation of Na+ ions into the host structure of layered Na0.5Co0.5Mn0.5O2 material. Accordingly, the sodium cell is delivered the initial charge-discharge capacity 53/144 mAh g-1 at 0.5 C, which cycling studies are extended to rate capability test at 1 C, 3 C and 5C. Eventually, the Na-ion full-cell is yielded cathode charge-discharge capacity 55/52 mAh g-1 at 0.212 mA and exhibited as a high voltage cathode for Na-ion batteries.

  19. Lithium-Excess Research of Cathode Material Li2MnTiO4 for Lithium-Ion Batteries

    OpenAIRE

    Zhang, Xinyi; Yang, Le; Hao, Feng; Chen, Haosen; Yang, Meng; Fang, Daining

    2015-01-01

    Lithium-excess and nano-sized Li2+xMn1−x/2TiO4 (x = 0, 0.2, 0.4) cathode materials were synthesized via a sol-gel method. The X-ray diffraction (XRD) experiments indicate that the obtained main phases of Li2.0MnTiO4 and the lithium-excess materials are monoclinic and cubic, respectively. The scanning electron microscope (SEM) images show that the as-prepared particles are well distributed and the primary particles have an average size of about 20–30 nm. The further electrochemical tests revea...

  20. Comparison Between Conventional Design and Cathode Gas Recirculation Design of a Direct-Syngas Solid Oxide Fuel Cell–Gas Turbine Hybrid Systems Part I: Design Performance

    Directory of Open Access Journals (Sweden)

    Vahid Azami

    2017-06-01

    Keywords: Solid oxide fuel cell, Gas turbine, Cathode gas recirculation, Exergy. Article History: Received Feb 23rd 2017; Received in revised form May 26th 2017; Accepted June 1st 2017; Available online How to Cite This Article: Azami, V, and Yari, M. (2017 Comparison between conventional design and cathode gas recirculation design of a direct-syngas solid oxide fuel cell–gas turbine hybrid systems part I: Design performance. International Journal of Renewable Energy Develeopment, 6(2, 127-136. https://doi.org/10.14710/ijred.6.2.127-136

  1. Electrochemical Reduction of Oxygen and Nitric Oxide at Low Temperature on La1−xSrxFeO3−δ Cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2014-01-01

    A series of six strontium-substituted lanthanum ferrites (La1-xSrxFeO3-delta, x = 0.00, 0.05, 0.15, 0.25, 0.35, and 0.50) were synthesized using the glycine-nitrate process and evaluated as cathodes for the electrochemical reduction of oxygen and nitric oxide in the temperature range 200 to 400...... degrees C, using cone-shaped electrodes and cyclic voltammetry. It was shown that the ferrites had a higher activity towards the electrochemical reduction of nitric oxide than towards the electrochemical reduction of oxygen, in the investigated temperature range. The highest activity towards...... the electrochemical reduction of nitric oxide was found for La0.95Sr0.05FeO3-delta at 400 degrees C. This compound also showed the highest activity towards the electrochemical reduction of oxygen at 400 degrees C. The highest apparent selectivity was found for the compound LaFeO3 at 200 degrees C. The materials...

  2. Synthesis of Nanoscale Lithium-Ion Battery Cathode Materials Using a Porous Polymer Precursor Method

    KAUST Repository

    Deshazer, H.D.

    2011-01-01

    Fine particles of metal oxides with carefully controlled compositions can be easily prepared by the thermal decomposition of porous polymers, such as cellulose, into which solutions containing salts of the desired cations have been dissolved. This is a simple and versatile method that can be used to produce a wide variety of materials with a range of particle sizes and carefully controlled chemical compositions. Examples of the use of this method to produce fine particles of LiCoO2 and Li(NiMnCo)1/3O2, which are used in the positive electrodes of lithium-ion batteries, are shown. Experiments have demonstrated that materials made using this method can have electrochemical properties comparable to those typically produced by more elaborate procedures. © 2011 The Electrochemical Society.

  3. Nanotubular MnO2/graphene oxide composites for the application of open air-breathing cathode microbial fuel cells.

    Science.gov (United States)

    Gnana Kumar, G; Awan, Zahoor; Suk Nahm, Kee; Xavier, J Stanley

    2014-03-15

    Nanotubular shaped α-MnO2/graphene oxide nanocomposites were synthesized via a simple, cost and time efficient hydrothermal method. The growth of hollow structured MnO2 nanotubes preferentially occurred along the [001] direction as evidenced from the morphological and structural characterizations. The tunnels of α-MnO2 nanotubes easily accommodated the molecular oxygen and exhibited excellent catalytic activity towards the oxygen reduction reaction over the rod structure and was further enhanced with the effective carbon support graphene oxide. The MnO2 nanotubes/graphene oxide nanocomposite modified electrode exhibited a maximum power density of 3359 mW m(-2) which is 7.8 fold higher than that of unmodified electrode and comparable with the Pt/C modified electrode. The microbial fuel cell equipped with MnO2 nanotubes/graphene oxide nanocomposite modified cathode exhibited quick start up and excellent durability over the studied electrodes and is attributed to the high surface area and number of active sites. These findings not only provide the fundamental studies on carbon supported low-dimensional transition-metal oxides but also open up the new possibilities of their applications in green energy devices. © 2013 Elsevier B.V. All rights reserved.

  4. Reduced graphene oxide and Fe{sub 2}(MoO{sub 4}){sub 3} composite for sodium-ion batteries cathode with improved performance

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Yubin [Institute for Clean Energy & Advanced Materials, Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China); Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Energies, Chongqing 400715 (China); Xu, Maowen, E-mail: xumaowen@swu.edu.cn [Institute for Clean Energy & Advanced Materials, Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China); Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Energies, Chongqing 400715 (China)

    2016-07-25

    Fe{sub 2}(MoO{sub 4}){sub 3}@reduced graphene oxide (FMO@rGO) composite have been synthesized by precipitation-hydrothermal method. Herein, the graphene oxide in the present synthesis acts not only as baffles between particle and particle that helps to prevent the increase of particle size, but also as conductive networks after hydrothermal treatment, providing high electronic conductivity between particle and particle. The special surface area of the as-prepared materials significantly increases from 19.738 m{sup 2} g{sup −1} (FMO) to 51.401 m{sup 2} g{sup −1} (FMO@rGO), which undoubtedly provide more interface area between the active materials and the electrolyte. As a cathode material for sodium-ion batteries, the FMO@rGO composite delivers high discharge capacity at 0.5 C, which is comparable to theoretical capacity and literatures, and impressive rate performance. As the current density is at 5 C, for the first time, the initial specific capacity of FMO@rGO composite is about 68.2 mAh g{sup −1}, and it remains 56.5 mAh g{sup −1} after 100 cycles, of which the excellent electrochemical performance is mainly attributed to good conductivity, high specific surface area and significantly enhanced diffusion coefficient. - Highlights: • Fe{sub 2}(MoO{sub 4}){sub 3}@reduced graphene oxide composite have been synthesized by hydrothermal method. • The obtained materials reveal large discharge capacity, outstanding rate performance and good stability. • The enhancement mechanism was explored.

  5. Reduced graphene oxide and Fe_2(MoO_4)_3 composite for sodium-ion batteries cathode with improved performance

    International Nuclear Information System (INIS)

    Niu, Yubin; Xu, Maowen

    2016-01-01

    Fe_2(MoO_4)_3@reduced graphene oxide (FMO@rGO) composite have been synthesized by precipitation-hydrothermal method. Herein, the graphene oxide in the present synthesis acts not only as baffles between particle and particle that helps to prevent the increase of particle size, but also as conductive networks after hydrothermal treatment, providing high electronic conductivity between particle and particle. The special surface area of the as-prepared materials significantly increases from 19.738 m"2 g"−"1 (FMO) to 51.401 m"2 g"−"1 (FMO@rGO), which undoubtedly provide more interface area between the active materials and the electrolyte. As a cathode material for sodium-ion batteries, the FMO@rGO composite delivers high discharge capacity at 0.5 C, which is comparable to theoretical capacity and literatures, and impressive rate performance. As the current density is at 5 C, for the first time, the initial specific capacity of FMO@rGO composite is about 68.2 mAh g"−"1, and it remains 56.5 mAh g"−"1 after 100 cycles, of which the excellent electrochemical performance is mainly attributed to good conductivity, high specific surface area and significantly enhanced diffusion coefficient. - Highlights: • Fe_2(MoO_4)_3@r