WorldWideScience

Sample records for cathode active material

  1. 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.

  2. 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.

  3. Cathode materials review

    International Nuclear Information System (INIS)

    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

  4. Dual active material composite cathode structures for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Whitacre, J.F. [Carnegie Mellon University, Departments of Materials Science and Engineering/Engineering and Public Policy, Pittsburgh, PA 15213 (United States); Zaghib, K. [Institut de Recherche d' Hydro-Quebec, 1800 Lionel Boulet, Varennes, QC (Canada); West, W.C.; Ratnakumar, B.V. [Jet Propulsion Laboratory, Electrochemical Technologies Group, California Institute of Technology, Pasadena, CA, 91109 (United States)

    2008-03-01

    The efficacy of composite Li-ion battery cathodes made by mixing active materials that possessed either high-rate capability or high specific energy was examined. The cathode structures studied contained carbon-coated LiFePO{sub 4} and either Li[Li{sub 0.17}Mn{sub 0.58}Ni{sub 0.25}]O{sub 2} or LiCoO{sub 2}. These active materials were arranged using three different electrode geometries: fully intermixed, fully separated, or layered. Discharge rate studies, cycle-life evaluation, and electrochemical impedance spectroscopy studies were conducted using coin cell test structures containing Li-metal anodes. Results indicated that electrode configuration was correlated to rate capability and degree of polarization if there was a large differential between the rate capabilities of the two active material species. (author)

  5. 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.

  6. A Ternary Polyaniline/Active Carbon/Lithium Iron Phosphate Composite as Cathode Material for Lithium Ion Battery.

    Science.gov (United States)

    Wang, Xiaohong; Zhang, Wuxing; Huang, Yunhui; Xia, Tian; Lian, Yongfu

    2016-06-01

    Lithium iron phosphate (LiFePO4) has been evaluated as the most promising cathode material for the next generation lithium-ion batteries because of its high operating voltage, good cycle performance, low cost, and environmentally friendly safety. However, pure LiFePO4 shows poor reversible capacity and charge/discharge performance at high current density. Many methods including optimization of particle size, introduction of coating carbon and conductive polymer, and the doping of metal and halogen ions have been developed to improve its electrochemical performance. In this study, conductive polymer polyaniline (PANI), active carbon and LiFePO4 (C-LFP/PANI) composite cathodes were successfully prepared by chemical oxidation method. Electrochemical performance shows that a remarkable improvement in capacity and rate performance can be achieved in the C-LFP/PANI composite cathodes with an addition of HCI. In comparison with C-LFP cathode, the C-LFP/PANI doped with HCl composite exhibits ca. 15% and 26% capacity enhancement at 0.2 C and 10 C, respectively. PMID:27427742

  7. 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.

  8. 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)

  9. Organic Cathode Materials for Rechargeable Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Ruiguo; Qian, Jiangfeng; Zhang, Jiguang; Xu, Wu

    2015-06-28

    This chapter will primarily focus on the advances made in recent years and specify the development of organic electrode materials for their applications in rechargeable lithium batteries, sodium batteries and redox flow batteries. Four various organic cathode materials, including conjugated carbonyl compounds, conducting polymers, organosulfides and free radical polymers, are introduced in terms of their electrochemical performances in these three battery systems. Fundamental issues related to the synthesis-structure-activity correlations, involved work principles in energy storage systems, and capacity fading mechanisms are also discussed.

  10. Characterisation of charge and discharge behaviour of lithium ion batteries with olivine based cathode active material

    Energy Technology Data Exchange (ETDEWEB)

    Roscher, Michael A.; Sauer, Dirk Uwe [RWTH Aachen University, Electrochemical Energy Conversion and Storage Systems Group, Institute for Power Electronics and Electrical Drives (ISEA), 52066 Aachen (Germany); Vetter, Jens [BMW Group, 80788 Muenchen (Germany)

    2009-06-15

    This paper gives insight to the physical processes taking part during the two-phase transition in lithium intercalation compounds. The behaviour of olivine based electrodes is in the special focus of this work. These electrodes exhibit phase juxtaposition within the electrode particles over a wide state of charge (SOC) range. Measurements were made to explore effects related to the formation of distinct phase sequences within the particles. Asymmetric charge characteristics, a load history dependency of the internal resistance and a voltage effect related to the disappearance of certain phase regions (the later on called vanishing phase effect) were identified. Moreover, these measurements give evidence to the existence of stable phase regions inside the electrode active material. An intuitive model is given to visualize the phase regions within spherical olivine particles. Therefore an analytical approach is developed in order to take the geometry of the particles, the ion permeability as well as the size distribution of the particles in consideration. According to the developed approach and the obtained measurement results, an enhanced cell equivalent electrical circuit is evaluated, considering phase shell development effects. (author)

  11. Intermetallics as cathode materials in the electrolytic hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Stojic, D.L.; Maksic, A.D.; Kaninski, M.P.M. [Vinca Inst. of Nuclear Sciences, Belgrade (Serbia and Montenegro). Lab. of Physical Chemistry; Cekic, B.D. [Vinca Inst. of Nuclear Sciences, Belgrade (Serbia and Montenegro). Lab. of Physics; Miljanic, S.S. [Belgrade Univ. (Serbia and Montenegro). Faculty of Physical Chemistry

    2005-01-01

    The intermetallics of transition metals have been investigated as cathode materials for the production of hydrogen by electrolysis from water-KOH solutions, in an attempt to increase the electrolytic process efficiency. We found that the best effect among all investigated cathodes (Hf{sub 2}Fe, Zr-Pt, Nb-Pd(I), Pd-Ta, Nb-Pd(II), Ti-Pt) exhibits the Hf{sub 2}Fe phase. These materials were compared with conventional cathodes (Fe and Ni), often used in the alkaline electrolysis. A significant upgrade of the electrolytic efficiency using intermetallics, either in pure KOH electrolyte or in combination with ionic activators added in situ, was achieved. The effects of these cathode materials on the process efficiency were discussed in the context of transition metal features that issue from their electronic configuration. (Author)

  12. Novel High Rate Lithium Intercalation Cathode Materials

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Application of amorphous V2O5/carbon/neodymium oxide (Nd2O3) composite is one of ways to surmount the lower electrical conductivity of V2O5. A new type of V2O5/carbon/Nd2O3 composite was prepared by mixing vanadium oxide hydrosol, acetone, carbon and Nd2O3 powder. High rate discharge/charge property of the composite electrode was tested electrochemically. This composite with Nd2O3 added shows the improvement of not only the discharge capacity but also cycle durability discharge capacity. The rate capability of the composite cathode also increases with the addition of Nd2O3.and cycle life are probably caused by the increase in porosity of open pores and short diffusion length of the active material on the lithium-ion insertion.

  13. Improvement of the cycling performance of LiNi(0.6)Co(0.2)Mn(0.2)O(2) cathode active materials by a dual-conductive polymer coating.

    Science.gov (United States)

    Ju, Seo Hee; Kang, Ik-Su; Lee, Yoon-Sung; Shin, Won-Kyung; Kim, Saheum; Shin, Kyomin; Kim, Dong-Won

    2014-02-26

    LiNi0.6Co0.2Mn0.2O2 cathode materials were surface-modified by coating with a dual conductive poly(3,4-ethylenedioxythiophene)-co-poly(ethylene glycol) (PEDOT-co-PEG) copolymer, and their resulting electrochemical properties were investigated. The surface-modified LiNi0.6Co0.2Mn0.2O2 cathode material exhibited a high discharge capacity and good high rate performance due to enhanced transport of Li(+) ions as well as electrons. The presence of a protective conducting polymer layer formed on the cathode also suppressed the growth of a resistive layer and inhibited the dissolution of transition metals from the active cathode materials, which resulted in more stable cycling characteristics than the pristine LiNi0.6Co0.2Mn0.2O2 cathode material at 55 (o)C. PMID:24460052

  14. Synopsis of Cathode No.4 Activation

    International Nuclear Information System (INIS)

    The purpose of this report is to describe the activation of the fourth cathode installed in the DARHT-II Injector. Appendices have been used so that an extensive amount of data could be included without danger of obscuring important information contained in the body of the report. The cathode was a 612 M type cathode purchased from Spectra-Mat. Section II describes the handling and installation of the cathode. Section III is a narrative of the activation based on information located in the Control Room Log Book supplemented with time plots of pertinent operating parameters. Activation of the cathode was performed in accordance with the procedure listed in Appendix A. The following sections provide more details on the total pressure and constituent partial pressures in the vacuum vessel, cathode heater power/filament current, and cathode temperature

  15. 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 and...

  16. Activated carbons derived from coconut shells as high energy density cathode material for Li-ion capacitors

    Science.gov (United States)

    Jain, Akshay; Aravindan, Vanchiappan; Jayaraman, Sundaramurthy; Kumar, Palaniswamy Suresh; Balasubramanian, Rajasekhar; Ramakrishna, Seeram; Madhavi, Srinivasan; Srinivasan, M. P.

    2013-10-01

    In this manuscript, a dramatic increase in the energy density of ~ 69 Wh kg-1 and an extraordinary cycleability ~ 2000 cycles of the Li-ion hybrid electrochemical capacitors (Li-HEC) is achieved by employing tailored activated carbon (AC) of ~ 60% mesoporosity derived from coconut shells (CS). The AC is obtained by both physical and chemical hydrothermal carbonization activation process, and compared to the commercial AC powders (CAC) in terms of the supercapacitance performance in single electrode configuration vs. Li. The Li-HEC is fabricated with commercially available Li4Ti5O12 anode and the coconut shell derived AC as cathode in non-aqueous medium. The present research provides a new routine for the development of high energy density Li-HEC that employs a mesoporous carbonaceous electrode derived from bio-mass precursors.

  17. NEW CATHODE MATERIALS FOR INERT AND OXIDIZING ATMOSPHERE PLASMA APPLICATION

    OpenAIRE

    Sadek, A; Kusumoto, K.; Ushio, M; Matsuda, F.

    1990-01-01

    This study has been carried out to develop new cathode materials for two types of thermionic cathode. First is concerning to the tungsten electrodes for the plasma furnace and welding torches. The second one is the electrodes for air plasma cutting torch. Tungsten electrodes activated with a single and combined additives of rare earth metal oxides, such as La2O3, Y2O3 and CeO2, are produced and pared with pure and thoriated tungsten electrode conventionally used, from the point of view of ele...

  18. 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

  19. Oxide diffusion in innovative SOFC cathode materials.

    Science.gov (United States)

    Hu, Y; Thoréton, V; Pirovano, C; Capoen, E; Bogicevic, C; Nuns, N; Mamede, A-S; Dezanneau, G; Vannier, R N

    2014-01-01

    Oxide diffusion was studied in two innovative SOFC cathode materials, Ba(2)Co(9)O(14) and Ca(3)Co(4)O(9)+δ derivatives. Although oxygen diffusion was confirmed in the promising material Ba(2)Co(9)O(14), it was not possible to derive accurate transport parameters because of an oxidation process at the sample surface which has still to be clarified. In contrast, oxygen diffusion in the well-known Ca(3)Co(4)O(9)+δ thermoelectric material was improved when calcium was partly substituted with strontium, likely due to an increase of the volume of the rock salt layers in which the conduction process takes place. Although the diffusion coefficient remains low, interestingly, fast kinetics towards the oxygen molecule dissociation reaction were shown with surface exchange coefficients higher than those reported for the best cathode materials in the field. They increased with the strontium content; the Sr atoms potentially play a key role in the mechanism of oxygen molecule dissociation at the solid surface. PMID:25407246

  20. 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.

  1. The structural and chemical origin of the oxygen redox activity in layered and cation-disordered Li-excess cathode materials.

    Science.gov (United States)

    Seo, Dong-Hwa; Lee, Jinhyuk; Urban, Alexander; Malik, Rahul; Kang, ShinYoung; Ceder, Gerbrand

    2016-07-01

    Lithium-ion batteries are now reaching the energy density limits set by their electrode materials, requiring new paradigms for Li(+) and electron hosting in solid-state electrodes. Reversible oxygen redox in the solid state in particular has the potential to enable high energy density as it can deliver excess capacity beyond the theoretical transition-metal redox-capacity at a high voltage. Nevertheless, the structural and chemical origin of the process is not understood, preventing the rational design of better cathode materials. Here, we demonstrate how very specific local Li-excess environments around oxygen atoms necessarily lead to labile oxygen electrons that can be more easily extracted and participate in the practical capacity of cathodes. The identification of the local structural components that create oxygen redox sets a new direction for the design of high-energy-density cathode materials. PMID:27325096

  2. Nanostructured cathode materials for rechargeable lithium batteries

    Science.gov (United States)

    Myung, Seung-Taek; Amine, Khalil; Sun, Yang-Kook

    2015-06-01

    The prospect of drastic climate change and the ceaseless fluctuation of fossil fuel prices provide motivation to reduce the use of fossil fuels and to find new energy conversion and storage systems that are able to limit carbon dioxide generation. Among known systems, lithium-ion batteries are recognized as the most appropriate energy storage system because of their high energy density and thus space saving in applications. Introduction of nanotechnology to electrode material is beneficial to improve the resulting electrode performances such as capacity, its retention, and rate capability. The nanostructure is highly available not only when used alone but also is more highlighted when harmonized in forms of core-shell structure and composites with carbon nanotubes, graphene or reduced graphene oxides. This review covers syntheses and electrochemical properties of nanoscale, nanosized, and nanostructured cathode materials for rechargeable lithium batteries.

  3. The influence of cathode material on electrochemical degradation of trichloroethylene in aqueous solution.

    Science.gov (United States)

    Rajic, Ljiljana; Fallahpour, Noushin; Podlaha, Elizabeth; Alshawabkeh, Akram

    2016-03-01

    In this study, different cathode materials were evaluated for electrochemical degradation of aqueous phase trichloroethylene (TCE). A cathode followed by an anode electrode sequence was used to support reduction of TCE at the cathode via hydrodechlorination (HDC). The performance of iron (Fe), copper (Cu), nickel (Ni), aluminum (Al) and carbon (C) foam cathodes was evaluated. We tested commercially available foam materials, which provide large electrode surface area and important properties for field application of the technology. Ni foam cathode produced the highest TCE removal (68.4%) due to its high electrocatalytic activity for hydrogen generation and promotion of HDC. Different performances of the cathode materials originate from differences in the bond strength between atomic hydrogen and the material. With a higher electrocatalytic activity than Ni, Pd catalyst (used as cathode coating) increased TCE removal from 43.5% to 99.8% for Fe, from 56.2% to 79.6% for Cu, from 68.4% to 78.4% for Ni, from 42.0% to 63.6% for Al and from 64.9% to 86.2% for C cathode. The performance of the palladized Fe foam cathode was tested for degradation of TCE in the presence of nitrates, as another commonly found groundwater species. TCE removal decreased from 99% to 41.2% in presence of 100 mg L(-1) of nitrates due to the competition with TCE for HDC at the cathode. The results indicate that the cathode material affects TCE removal rate while the Pd catalyst significantly enhances cathode activity to degrade TCE via HDC. PMID:26761603

  4. Novel Composite Materials for SOFC Cathode-Interconnect Contact

    Energy Technology Data Exchange (ETDEWEB)

    J. H. Zhu

    2009-07-31

    This report summarized the research efforts and major conclusions of our University Coal Research Project, which focused on developing a new class of electrically-conductive, Cr-blocking, damage-tolerant Ag-perovksite composite materials for the cathode-interconnect contact of intermediate-temperature solid oxide fuel cell (SOFC) stacks. The Ag evaporation rate increased linearly with air flow rate initially and became constant for the air flow rate {ge} {approx} 1.0 cm {center_dot} s{sup -1}. An activation energy of 280 KJ.mol{sup -1} was obtained for Ag evaporation in both air and Ar+5%H{sub 2}+3%H{sub 2}O. The exposure environment had no measurable influence on the Ag evaporation rate as well as its dependence on the gas flow rate, while different surface morphological features were developed after thermal exposure in the oxidizing and reducing environments. Pure Ag is too volatile at the SOFC operating temperature and its evaporation rate needs to be reduced to facilitate its application as the cathode-interconnect contact. Based on extensive evaporation testing, it was found that none of the alloying additions reduced the evaporation rate of Ag over the long-term exposure, except the noble metals Au, Pt, and Pd; however, these noble elements are too expensive to justify their practical use in contact materials. Furthermore, the addition of La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSM) into Ag to form a composite material also did not significantly modify the Ag evaporation rate. The Ag-perovskite composites with the perovskite being either (La{sub 0.6}Sr{sub 0.4})(Co{sub 0.8}Fe{sub 0.2})O{sub 3} (LSCF) or LSM were systematically evaluated as the contact material between the ferritic interconnect alloy Crofer 22 APU and the LSM cathode. The area specific resistances (ASRs) of the test specimens were shown to be highly dependent on the volume percentage and the type of the perovskite present in the composite contact material as well as the amount of thermal cycling

  5. 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

  6. Explicit formulae for the internal stress in spherical particles of active material within lithium ion battery cathodes during charging and discharging

    International Nuclear Information System (INIS)

    Highlights: • Closed form expression proposed for Li ion concentration in a spherical particle. • This solution for fast (dis)charging depends explicitly on time and radius. • Explicit internal stress solution derived further is useful in design calculations. - Abstract: The fundamental process underlying the operation of lithium ion batteries is the diffusion of charge-carrying ions through the electrolyte that separates the anode from the cathode, and the reversible insertion of lithium ions into the host material’s crystal structure (intercalation and de-intercalation). Alongside the principal electrochemical consequences of this process, mechanical phenomena that accompany (de)intercalation are of fundamental significance for deformation and fragmentation of the active materials, since it is these phenomena that ultimately determine the battery structural integrity and durability. This article presents a sequentially coupled analytical treatment of the transient diffusion and stress analysis (eigenstrain) problem related to the lithiation and de-lithiation processes at the level of an individual spherical secondary particle of active material. Explicit closed form approximate solutions are derived for the stresses that arise within the particles during fast charging. They provide a firm basis for the assessment of the charging conditions influence on the internal stress states and the effects on battery damage, mechanical integrity and durability

  7. Power generation using an activated carbon and metal mesh cathode in a microbial fuel cell

    KAUST Repository

    Zhang, Fang

    2009-11-01

    An inexpensive activated carbon (AC) air cathode was developed as an alternative to a platinum-catalyzed electrode for oxygen reduction in a microbial fuel cell (MFC). AC was cold-pressed with a polytetrafluoroethylene (PTFE) binder to form the cathode around a Ni mesh current collector. This cathode construction avoided the need for carbon cloth or a metal catalyst, and produced a cathode with high activity for oxygen reduction at typical MFC current densities. Tests with the AC cathode produced a maximum power density of 1220 mW/m2 (normalized to cathode projected surface area; 36 W/m3 based on liquid volume) compared to 1060 mW/m2 obtained by Pt catalyzed carbon cloth cathode. The Coulombic efficiency ranged from 15% to 55%. These findings show that AC is a cost-effective material for achieving useful rates of oxygen reduction in air cathode MFCs. © 2009 Elsevier B.V. All rights reserved.

  8. 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

  9. The dependence of vircator oscillation mode on cathode material

    Science.gov (United States)

    Li, Limin; Liu, Lie; Cheng, Guoxin; Xu, Qifu; Wan, Hong; Chang, Lei; Wen, Jianchun

    2009-06-01

    This paper presents the effects of cathode materials on the oscillation mode of a virtual cathode oscillator (vircator). In the case of the stainless steel cathode, an oscillation mode hopping appeared with two separate frequencies. Interestingly, the vircator using the carbon fiber cathode exhibited an almost unchanged microwave frequency throughout the microwave pulse. To understand this phenomenon, several parameters are compared, including the diode voltage, accelerating gap, emitting area, and beam uniformity. It was found that a flat-top voltage and a relatively stable gap will provide a possibility of generating a constant microwave frequency. Further, the cathode operated in a regime where the beam current was between the space-charge limited current determined by Child-Langmuir law and the bipolar flow. On the cathode surface, the electron emission is initiated from discrete plasma spots and next from a continuing area, while there is a liberation process of multilayer gases on the anode surface. The changes in the emitting area of carbon fiber cathode showed a self-quenching process, which is not observed in the case of stainless steel cathode. The two-dimensional effect of microwave frequency is introduced, and the obtained results supported the experimental observations on the oscillation mode. By examining the cross section of electron beam, the electron beam for carbon fiber cathode was significantly centralized, while the discrete beam spots appeared for stainless steel cathode. These results show that the slowed diode closure, high emission uniformity, and stable microwave frequency tend to be closely tied.

  10. Studies on Stability of a Novel Cathode Material for MCFC

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The stability of NiO and oxidized nickel-niobium surface alloy electrode under various molten carbonate fuel cell(MCFC) cathode conditions were investigated by determination of equilibrium solubility of nickel ions in the carbonate melt of the two electrode materials.It is found that under MCFC cathode conditions the stability of NiO electrode is improved significantly by the deposition of niobium.As far as stability is concerned,oxidized nickel-niobium alloy electrode can be considered as a candidate for cathode material of MCFC.

  11. A review of blended cathode materials for use in Li-ion batteries

    Science.gov (United States)

    Chikkannanavar, Satishkumar B.; Bernardi, Dawn M.; Liu, Lingyun

    2014-02-01

    Several commercial automotive battery suppliers have developed lithium ion cells which use cathodes that consist of a mixture of two different active materials. This approach is intended to take advantage of the unique properties of each material and optimize the performance of the battery with respect to the automotive operating requirements. Certain cathode materials have high coulombic capacity and good cycling characteristics, but are costly and exhibit poor thermal stability (e.g., LiNixCo1-x-yAlyO2). Alternately, other cathode materials exhibit good thermal stability, high voltage and high rate capability, but have low capacity (e.g., LiMn2O4). By blending two cathode materials the shortcomings of the parent materials could be minimized and the resultant blend can be tailored to have a higher energy or power density coupled with enhanced stability and lower cost. In this review, we survey the developing field of blended cathode materials from a new perspective. Targeting a range of cathode materials, we survey the advances in the field in the current review. Limitations, such as capacity decay due to metal dissolution are also discussed, as well as how the appropriate balance of characteristics of the blended materials can be optimized for hybrid- and electric-vehicle applications.

  12. A study around the improvement of electrochemical activity of MnO2 as cathodic material in alkaline batteries

    International Nuclear Information System (INIS)

    An optimized combination of reduction by methane and sulfuric acid digestion was developed to improve the electrochemical activity of manganese dioxide at a battery set. Chemical manganese dioxide, CMD, and electrolytic manganese dioxide, EMD, which have been destroyed after discharge cycling process in potential window of 900-1650 mV versus Hg/HgO, were reduced in a furnace with a flow of methane at 300 and 250 deg. C correspondingly. Thereafter, the reduced samples, CMDr and EMDr, were digested in a solution of sulfuric acid with optimized concentration and temperature. It was found that digested samples, CMDro and EMDro, typically show more stability in cycling, higher capacity and more reversible redox reaction. Alternatively, we reported about the effect of digestion temperature on electrochemical and structural properties of the samples. Digestion at temperatures 60 and 98 deg. C in 1.5 M sulfuric acid as superior concentration was preferred after comparative experiments in the range 40-98 deg. C. The samples which were digested in 60 deg. C (CMDro1 and EMDro1) showed superior electrochemical activity at the early stages of discharge cycling. By contrast, the samples which were obtained at 98 deg. C (CMDro2 and EMDro2) showed more stability and were superior to the former samples in final stages of discharge cycling process. Afterward, the electrochemical behavior of the pretreated samples was investigated by means of cyclic voltammetry technique and discharge cumulative capacity profiles. Also X-ray diffraction was employed to verify the responses of voltammetric methods. In XRD patterns, peak at 2θ = 28.6 deg. which is due to β-MnO2 type was the strongest signal as temperature 98 deg. C was selected for digestion. After digestion at 60 deg. C, the characteristic peaks at 2θ = 38 deg. and 42 deg. were amplified which are attributed to formation of γ-MnO2. Interestingly enough, the results according to the XRD patterns were in good agreement with the

  13. A study around the improvement of electrochemical activity of MnO{sub 2} as cathodic material in alkaline batteries

    Energy Technology Data Exchange (ETDEWEB)

    Ghaemi, M.; Gholami, A. [Department of Chemistry, Science Faculty, Tarbiat Modares University, Tehran (Iran); Moghaddam, R.B. [Department of Chemistry, K.N. Toosi University of Technology, 15875-4416 Tehran (Iran)

    2008-03-10

    An optimized combination of reduction by methane and sulfuric acid digestion was developed to improve the electrochemical activity of manganese dioxide at a battery set. Chemical manganese dioxide, CMD, and electrolytic manganese dioxide, EMD, which have been destroyed after discharge cycling process in potential window of 900-1650 mV versus Hg/HgO, were reduced in a furnace with a flow of methane at 300 and 250{sup o}C correspondingly. Thereafter, the reduced samples, CMDr and EMDr, were digested in a solution of sulfuric acid with optimized concentration and temperature. It was found that digested samples, CMDro and EMDro, typically show more stability in cycling, higher capacity and more reversible redox reaction. Alternatively, we reported about the effect of digestion temperature on electrochemical and structural properties of the samples. Digestion at temperatures 60 and 98{sup o}C in 1.5 M sulfuric acid as superior concentration was preferred after comparative experiments in the range 40-98{sup o}C. The samples which were digested in 60{sup o}C (CMDro1 and EMDro1) showed superior electrochemical activity at the early stages of discharge cycling. By contrast, the samples which were obtained at 98{sup o}C (CMDro2 and EMDro2) showed more stability and were superior to the former samples in final stages of discharge cycling process. Afterward, the electrochemical behavior of the pretreated samples was investigated by means of cyclic voltammetry technique and discharge cumulative capacity profiles. Also X-ray diffraction was employed to verify the responses of voltammetric methods. In XRD patterns, peak at 2{theta} = 28.6 which is due to {beta}-MnO{sub 2} type was the strongest signal as temperature 98{sup o}C was selected for digestion. After digestion at 60{sup o}C, the characteristic peaks at 2{theta} = 38 and 42 were amplified which are attributed to formation of {gamma}-MnO{sub 2}. Interestingly enough, the results according to the XRD patterns were in good

  14. Theory, Investigation and Stability of Cathode Electrocatalytic Activity

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Dong; Liu, Mingfei; Lai, Samson; Blinn, Kevin; Liu, Meilin

    2012-09-30

    conditions. This was also confirmed by x-ray analyses. For example, soft x-ray XANES data reveal that Co cations displace the Mn cations as being more favored to be reduced. Variations in the Sr-O in the annealed LSCF Fourier-transformed (FT) EXAFS suggest that some Sr segregation is occurring, but is not present in the annealed LSM-infiltrated LSCF cathode materials. Further, a surface enhanced Raman technique was also developed into to probe and map LSM and LSCF phase on underlying YSZ substrate, enabling us to capture important chemical information of cathode surfaces under practical operating conditions. Electrochemical models for the design of test cells and understanding of mechanism have been developed for the exploration of fundamental properties of electrode materials. Novel catalyst coatings through particle depositions (SDC, SSC, and LCC) or continuous thin films (PSM and PSCM) were successfully developed to improve the activity and stability of LSCF cathodes. Finally, we have demonstrated enhanced activity and stability of LSCF cathodes over longer periods of time in homemade and commercially available cells by an optimized LSM infiltration process. Microstructure examination of the tested cells did not show obvious differences between blank and infiltrated cells, suggesting that the infiltrated LSM may form a coherent film on the LSCF cathodes. There was no significant change in the morphology or microstructure of the LSCF cathode due to the structural similarity of LSCF and LSM. Raman analysis of the tested cells indicated small peaks emerging on the blank cells that correspond to trace amounts of secondary phase formation during operation (e.g., CoO{sub x}). The formation of this secondary phase might be attributed to performance degradation. In contrast, there was no such secondary phase observed in the LSM infiltrated cells, indicating that the LSM modification staved off secondary phase formation and thus improved the stability.

  15. Lanthanides: new metallic cathode materials for organic photovoltaic cells.

    Science.gov (United States)

    Nikiforov, Maxim P; Strzalka, Joseph; Jiang, Zhang; Darling, Seth B

    2013-08-21

    Organic photovoltaics (OPVs) are compliant with inexpensive, scalable, and environmentally benign manufacturing technologies. While substantial attention has been focused on optimization of active layer chemistry, morphology, and processing, far less research has been directed to understanding charge transport at the interfaces between the electrodes and the active layer. Electrical properties of these interfaces not only impact efficiency, but also play a central role in stability of organic solar cells. Low work function metals are the most widely used materials for the electron transport layer with Ca being the most common material. In bulk heterojunction OPV devices, low work function metals are believed to mirror the role they play in OLEDs, where such metals are used to control carrier selectivity, transport, extraction, and blocking, as well as interface band bending. Despite their advantages, low work function materials are generally prone to reactions with water, oxygen, nitrogen, and carbon dioxide from air leading to rapid device degradation. Here we discuss the search for a new metallic cathode interlayer material that increases device stability and still provides device efficiency similar to that achieved with a Ca interlayer.

  16. 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.

  17. Novel Nanosized Adsorbing Composite Cathode Materials for the Next Generational Lithium Battery

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong; ZHENG Wei; ZHANG Ping; WANG Lizhen; XIA Tongchi; HU Xinguo; YU Zhenxing

    2007-01-01

    A novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon (HSAAC) under certain conditions. The physical and chemical performances of the novel carbon-sulfur nano-composite were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and X-ray diffraction (XRD). The electrochemical performances of nano-composite were characterized by charge-discharge characteristic, cyclic voltammetry and electrochemical impendence spectroscopy (EIS). The experimental results indicate that the electrochemical capability of nanocomposite material was superior to that of traditional S-containing composite material. The cathode made by carbon-sulfur nano-composite material shows a good cycle ability and a high specific charge-discharge capacity. The HSAAC shows a vital role in adsorbing sublimed sulfur and the polysulfides within the cathode and is an excellent electric conductor for a sulfur cathode and prevents the shuttle behavior of the lithium-sulfur battery.

  18. PVC DISULFIDE AS CATHODE MATERIALS FOR SECONDARY LITHIUM BATTERIES

    Institute of Scientific and Technical Information of China (English)

    Guo-xiang Xu; Lu Qi; Bi-tao Yu; Lei Wen

    2006-01-01

    PVC disulfide (2SPVC) was synthesized by solution crosslink and its molecular structure was confirmed by the particle size of d0.5 = 11.3 μm. With SEM (Scanning Electron Microscope) experiment the surface morphology and obvious S-S redox reaction in charge-discharge process. When 2SPVC was used as cathode material for secondary lithium mixture of o-xylene (oxy), diglyme (DG) and dimethoxymethane (DME) at 30℃, the first discharge capacity of 2SPVC is very promising cathode candidate for rechargeable lithium batteries.

  19. A Novel Method to Improve the Electrochemical Performance of LiMn2O4 Cathode Active Material by CaCO3 Surface Coating

    Institute of Scientific and Technical Information of China (English)

    Halil Sahan; Hüseyin G(o)ktepe; Saban Patat

    2011-01-01

    Spinel LiMn2O4 was synthesized by glycine-nitrate method and coated with CaCO3 in order to enhance the electrochemical performance at room temperature (25℃) and 55℃. The uncoated and CaCO3-coated LiMn2O4 materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical tests. XRD and SEM results indicated that CaCO3 particles encapsulated the surface of the LiMn2O4 without causing any structural change. The charge-discharge tests showed that the specific discharge capacity fade of pristine electrode at 25 and 55℃ were 25.5% and 52%, respectively. However, surface modified cathode shows 7.4% and 29.5% loss compared to initial specific discharge capacity at 70th cycle for 25 and 55℃, respectively. The improvement of electrochemical performance is attributed to suppression of Mn2+dissolution into electrolyte via CaCO3 layer.

  20. Hollow cathode arc: effect of the cathode material on the internal plasma

    International Nuclear Information System (INIS)

    In discharges with hollow cathodes functioning in the arc regime, the cathode emits thermionic electrons which ionize the gas. To reduce the electrical power consumed by these discharges, cathodes made of thoriated tungsten and lathanum hexaboride have been used. The parameters of the plasma generated into the cathode have been measured with electrostatic probes. (Auth.)

  1. Titanium Dioxide as a Cathode Material in a Dry Cell

    Directory of Open Access Journals (Sweden)

    Duncan ALOKO

    2007-09-01

    Full Text Available Titanium dioxide was proposed as an alternative cathode material in place of Manganesse (IV oxide. TiO2 was found to be highly polarized when in an electric field and its surface area of adsorption of solution determined to be 1070.32 m2/g. The adsorption of alkaline anions (i.e. SO42- , NO3-, Cl- and Br- were investigated. The anions were adsorbed between the layers of the cathode material thereby altering its surface texture for a better performance. Increase in concentration of the anions solution enhances greater electric surface charge. Thus, sulphate ion is having the best result as compared to other anions because of its highest electric charge and adsorption at 1M concentration of solution. This is in agreement with the relative position of ions in the electrochemical series in the decreasing order of electro- negativity as well as in the increasing order of preference for discharge.

  2. 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.

  3. 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.

  4. Correlation of cathode parameters of high power grid tubes with material characteristics of cathode-grid units

    International Nuclear Information System (INIS)

    One way to increase the longevity of dispenser cathodes is based on reducing the Barium evaporation. This can be achieved by the decrease of the reaction 'activity' of the emitter impregnant with the porous tungsten (W) body, which supplies free Barium from the interior of the porous cathode to its surface

  5. In Situ XRD and XAS Investigation of Cathode Materials in Li-ion Battery

    Institute of Scientific and Technical Information of China (English)

    J.G.Duh; P.Y.Liao; H.W.Chan; S.Y.Tsai

    2007-01-01

    1 Results Lithium ion batteries have been widely used in modern portable electronics,such as cellular phones and notebook computers,because of their low cost,long life,and high energy density.In the lithium ion batteries,the cathode provides lithium ion source and plays a critical role to determinate the performance of battery.Lithium transition metal oxides have been investigated as active cathode materials due to their high potential versus Li/Li+ and large proportion of the lithium ions can be insert...

  6. Preparation and Investigation of a Novel Organic Polymer Consisting of 2,2,6,6-Tetramethylpiperidine-N-oxy as a Cathode Active Material in Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Emre Biçer

    2013-01-01

    Full Text Available In the present study, a novel organic polymer consisting of 2,2,6,6-tetramethylpiperidine-N-oxyl group as an electroactive center is employed by synthesizing it from a commercially ready polymer. An investigation on electrochemical and battery properties of this material as a cathode active material in different electrolyte salts was conducted. A coin cell shows a discharge capacity of 40 mAh g−1 at 1 C which is 76% of its theoretical capacity. It is observed that there is no significant decrease in capacity value even at 2 C and 5 C which indicates that it is applicable for the high-power applications. Besides, a good cycle stability is obtained with the organic radical battery.

  7. Poly(vinyl alcohol) separators improve the coulombic efficiency of activated carbon cathodes in microbial fuel cells

    KAUST Repository

    Chen, Guang

    2013-09-01

    High-performance microbial fuel cell (MFC) air cathodes were constructed using a combination of inexpensive materials for the oxygen reduction cathode catalyst and the electrode separator. A poly(vinyl alcohol) (PVA)-based electrode separator enabled high coulombic efficiencies (CEs) in MFCs with activated carbon (AC) cathodes without significantly decreasing power output. MFCs with AC cathodes and PVA separators had CEs (43%-89%) about twice those of AC cathodes lacking a separator (17%-55%) or cathodes made with platinum supported on carbon catalyst (Pt/C) and carbon cloth (CE of 20%-50%). Similar maximum power densities were observed for AC-cathode MFCs with (840 ± 42 mW/m2) or without (860 ± 10 mW/m2) the PVA separator after 18 cycles (36 days). Compared to MFCs with Pt-based cathodes, the cost of the AC-based cathodes with PVA separators was substantially reduced. These results demonstrated that AC-based cathodes with PVA separators are an inexpensive alternative to expensive Pt-based cathodes for construction of larger-scale MFC reactors. © 2013 Elsevier B.V. All rights reserved.

  8. Analysis of cathode materials of perovskite structure for solid oxide fuel cells, sofc s

    International Nuclear Information System (INIS)

    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 (ABO3), more efficient than the traditionally used La1-xSrxMnO3-δ (LSM) or (La, Sr) CoO3. Such is the case of mixed conductors (MIEC) double perovskite structure (A A B2O5+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)

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

    International Nuclear Information System (INIS)

    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 LiMO2 (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

  10. Understanding electrochemical potentials of cathode materials in rechargeable batteries

    Directory of Open Access Journals (Sweden)

    Chaofeng Liu

    2016-03-01

    Full Text Available Presently, sustainable energy as well as efficient and economical energy conversion and storage technologies has become important work in light of the rising environmental issues and dependence on portable and uninterrupted power sources. Increasingly more researchers are focusing on harvesting and converting solar energy, mechanical vibration, waste heat, and wind to electricity. Electrical energy storage technologies play a significant role in the demand for green and sustainable energy. Rechargeable batteries or secondary batteries, such as Li-ion batteries, Na-ion batteries, and Mg-ion batteries, reversibly convert between electrical and chemical energy via redox reactions, thus storing the energy as chemical potential in their electrodes. The energy density of a rechargeable battery is determined collectively by the specific capacity of electrodes and the working voltage of the cell, which is the differential potential between the cathode and the anode. Over the past decades, a significant number of studies have focused on enhancing this specific capacity; however, studies to understand and manipulate the electrochemical potential of the electrode materials are limited. In this review, the material characteristics that determine and influence the electrochemical potentials of electrodes are discussed. In particular, the cathode materials that convert electricity and chemical potential through electrochemical intercalation reactions are investigated. In addition, we summarize the selection criteria for elements or compounds and the effect of the local atomic environment on the discharge potential, including the effects of site energy, defects, crystallinity, and microstructure, using LiMn2O4, V2O5, Mo6S8, LiFePO4, and LiCoO2 as model samples for discussion.

  11. Development and evaluation of carbon and binder loading in low-cost activated carbon cathodes for air-cathode microbial fuel cells

    KAUST Repository

    Wei, Bin

    2012-01-01

    Activated carbon (AC) air cathodes were constructed using variable amounts of carbon (43-171 mg cm-2) and an inexpensive binder (10 wt% polytetrafluoroethylene, PTFE), and with or without a porous cloth wipe-based diffusion layer (DL) that was sealed with PDMS. The cathodes with the highest AC loading of 171 mg cm-2, and no diffusion layer, produced 1255 ± 75 mW m-2 and did not appreciably vary in performance after 1.5 months of operation. Slightly higher power densities were initially obtained using 100 mg cm-2 of AC (1310 ± 70 mW m-2) and a PDMS/wipe diffusion layer, although the performance of this cathode decreased to 1050 ± 70 mW m-2 after 1.5 months, and 1010 ± 190 mW m-2 after 5 months. AC loadings of 43 mg cm-2 and 100 mg cm-2 did not appreciably affect performance (with diffusion layers). MFCs with the Pt catalyst and Nafion binder initially produced 1295 ± 13 mW m-2, but the performance decreased to 930 ± 50 mW m -2 after 1.5 months, and then to 890 ± 20 mW m-2 after 5 months. Cathode performance was optimized for all cathodes by using the least amount of PTFE binder (10%, in tests using up to 40%). These results provide a method to construct cathodes for MFCs that use only inexpensive AC and a PTFE, while producing power densities similar to those of Pt/C cathodes. The methods used here to make these cathodes will enable further tests on carbon materials in order to optimize and extend the lifetime of AC cathodes in MFCs. © 2012 The Royal Society of Chemistry.

  12. Nanostructured material for advanced energy storage : magnesium battery cathode development.

    Energy Technology Data Exchange (ETDEWEB)

    Sigmund, Wolfgang M. (University of Florida, Gainesville, FL); Woan, Karran V. (University of Florida, Gainesville, FL); Bell, Nelson Simmons

    2010-11-01

    Magnesium batteries are alternatives to the use of lithium ion and nickel metal hydride secondary batteries due to magnesium's abundance, safety of operation, and lower toxicity of disposal. The divalency of the magnesium ion and its chemistry poses some difficulties for its general and industrial use. This work developed a continuous and fibrous nanoscale network of the cathode material through the use of electrospinning with the goal of enhancing performance and reactivity of the battery. The system was characterized and preliminary tests were performed on the constructed battery cells. We were successful in building and testing a series of electrochemical systems that demonstrated good cyclability maintaining 60-70% of discharge capacity after more than 50 charge-discharge cycles.

  13. Mercury vapor hollow cathode component studies. [emissive materials for ion thruster requirements

    Science.gov (United States)

    Zuccaro, D. E.

    1973-01-01

    An experimental study of starting and operating characteristics of conventional hollow cathodes and of hollow cathodes without alkaline earth emissive materials demonstrated that the emissive mix is essential to obtain the desired cathode operation. Loss of the emissive mix by evaporation and chemical reaction was measured. New insert designs consisting of emissive mix supported on nickel and of barium impregnated porous tungsten were studied. Cathodes with a modified orifice geometry operated in a low voltage, 'spot' mode over a broad range of discharge current. Thermal degradation tests on cathode heaters showed the flame sprayed SERT II type to be the most durable at high temperatures. Thermal shock was observed to be a significant factor in limiting cathode heater life. A cathode having a barium impregnated porous tungsten tip and a heater which is potted in sintered alumina was found to have favorable operating characteristics.

  14. Power generation using an activated carbon fiber felt cathode in an upflow microbial fuel cell

    KAUST Repository

    Deng, Qian

    2010-02-01

    An activated carbon fiber felt (ACFF) cathode lacking metal catalysts is used in an upflow microbial fuel cell (UMFC). The maximum power density with the ACFF cathode is 315 mW m-2, compared to lower values with cathodes made of plain carbon paper (67 mW m-2), carbon felt (77 mW m-2), or platinum-coated carbon paper (124 mW m-2, 0.2 mg-Pt cm-2). The addition of platinum to the ACFF cathode (0.2 mg-Pt cm-2) increases the maximum power density to 391 mW m-2. Power production is further increased to 784 mW m-2 by increasing the cathode surface area and shaping it into a tubular form. With ACFF cutting into granules, the maximum power is 481 mW m-2 (0.5 cm granules), and 667 mW m-2 (1.0 cm granules). These results show that ACFF cathodes lacking metal catalysts can be used to substantially increase power production in UMFC compared to traditional materials lacking a precious metal catalyst. © 2009 Elsevier B.V.

  15. Hydrogen Induced Stress Cracking of Materials Under Cathodic Protection

    Science.gov (United States)

    LaCoursiere, Marissa P.

    Hydrogen embrittlement of AISI 4340, InconelRTM 718, Alloy 686 and Alloy 59 was studied using slow strain rate tests of both smooth and notched cylindrical specimens. Two heat treatments of the AISI 4340 material were used as a standard for two levels of yield strength: 1479 MPa, and 1140 MPa. A subset of the 1140 MPa AISI 4340 material also underwent plasma nitriding. The InconelRTM 718 material was hardened following AMS 5663M to obtain a yield strength of 1091 MPa. The Alloy 686 material was obtained in the Grade 3 condition with a minimum yield strength of 1034 MPa. The Alloy 59 material was obtained with a cold worked condition similar to the Alloy 686 and with a minimum yield strength of 1034 MPa. Ninety-nine specimens were tested, including smooth cylindrical tensile test specimens and smooth and notched cylindrical slow strain rate tensile tests specimens. Testing included specimens that had been precharged with hydrogen in 3.5% NaCl at 50°C for 2 weeks (AISI 4340), 4 weeks (InconelRTM 718, Alloy 686, Alloy 59) and 16 weeks (InconelRTM 718, Alloy 686, Alloy 59) using a potentiostat to deliver a cathodic potential of -1100 mV vs. SCE. The strain rate over the gauge section for the smooth specimens and in the notch root for the notched specimens was 1 x 10-6 /s. It was found that the AISI 4340 was highly embrittled in simulated ocean water when compared to the nickel based superalloys. The higher strength AISI 4340 showed much more embrittlement, as expected. Testing of the AISI 4340 at both 20°C and 4°C showed that the temperature had no effect on the hydrogen embrittlement response. The InconelRTM 718 was highly embrittled when precharged, although it only showed low levels of embrittlement when unprecharged. Both the Alloy 686 and Alloy 59 showed minimal embrittlement in all conditions. Therefore, for the materials examined, the use of Alloy 686 and Alloy 59 for components in salt water environments when under a cathodic potential of -1100 mV vs. SCE is

  16. Improved Cycle Properties of FeS2 Cathode Material with Metallic Additives

    Institute of Scientific and Technical Information of China (English)

    Jae-Won Choi; Jae-Kwang Kim; Gouri Cheruvally; Jou-Hyeon Ahn; Ki-Won Kim; Hyo-Jun Ahn; Dong-Kyu Park

    2007-01-01

    Iron disulfide (FeS2) cathode active material was prepared from iron and sulfur at room temperature by high energy mechanical alloying. Modified FeS2 composites containing Co or Ni transition metal powders as additives were also prepared by the same method. Lithium cells with these FeS2 cathodes were studied for charge-discharge properties at room temperature using 0.5M LiTFSI in tetra(ethylene glycol) dimethyl ether (TEGDME) solvent. Cyclic voltammetry showed two anodic oxidation peaks at 1.8 and 2.5V and two cathodic reduction peaks at 2.0 and 1.3 V for FeS2 with metal additives. The addition of 5wt% Co and 3wt% Ni resulted in an enhancement of the first discharge capacity giving 571 and 844mAh/g respectively at 0.1C-rate. The cycle performance was also enhanced remarkably by the addition of these electrically conductive transition metals in the active material. FeS2 with 5wt% Co exhibited a stable cycle performance delivering a reversible capacity of 338mAh/g (37.8% of theoretical capacity) after 20 cycles.

  17. Long-term performance of activated carbon air cathodes with different diffusion layer porosities in microbial fuel cells

    KAUST Repository

    Zhang, Fang

    2011-08-01

    Activated carbon (AC) air-cathodes are inexpensive and useful alternatives to Pt-catalyzed electrodes in microbial fuel cells (MFCs), but information is needed on their long-term stability for oxygen reduction. AC cathodes were constructed with diffusion layers (DLs) with two different porosities (30% and 70%) to evaluate the effects of increased oxygen transfer on power. The 70% DL cathode initially produced a maximum power density of 1214±123mW/m 2 (cathode projected surface area; 35±4W/m 3 based on liquid volume), but it decreased by 40% after 1 year to 734±18mW/m 2. The 30% DL cathode initially produced less power than the 70% DL cathode, but it only decreased by 22% after 1 year (from 1014±2mW/m 2 to 789±68mW/m 2). Electrochemical tests were used to examine the reasons for the degraded performance. Diffusion resistance in the cathode was found to be the primary component of the internal resistance, and it increased over time. Replacing the cathode after 1 year completely restored the original power densities. These results suggest that the degradation in cathode performance was due to clogging of the AC micropores. These findings show that AC is a cost-effective material for oxygen reduction that can still produce ~750mW/m 2 after 1 year. © 2011 Elsevier B.V.

  18. Materials Characterization of Impregnated W and W-Ir Cathodes after Oxygen Poisoning

    OpenAIRE

    Polk, James E.; Capece, Angela M.

    2015-01-01

    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 discharg...

  19. Carbon Fiber as Anode Material for Cathodic Prevention in Cementitious Materials

    OpenAIRE

    Zhang, Emma Qingnan; Tang, Luping; Zack, Thomas

    2016-01-01

    Cathodic prevention (CPre) technique is a promising method and has been used for the past two decades to prevent steel from corrosion in concrete structures. However, wide application of this technique has been restricted due to high costs of anode materials. In order to lower the cost and further improve this technique, carbon fiber composite anode has been introduced as an alternative anode material with affordable price and other outstanding properties. This paper presents the study of usi...

  20. A new high power thermal battery cathode material

    International Nuclear Information System (INIS)

    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

  1. Microwave synthesis of LiCoO2 cathode materials

    Institute of Scientific and Technical Information of China (English)

    YU Yong-li; ZHAI Xiu-jing; FU Yan; YAO Guang-chun

    2005-01-01

    LiCoO2 powder used as cathode material for lithium ion battery was synthesized by microwave heating markedly affect the purity, morphology and electrochemical behaviors of the samples. X-ray diffraction (XRD) patterns display that the samples synthesized at 360 W for 10 min are pure layered LiCoO2, and SEM photos show that the powders are crystalline with well-defined facets whose sizes are about 5 μm. The performance of Co3O4 and starting materials by microwave heating and conventional heating was investigated. It is indicated that Co3O4 decomposes into CoO in microwave field at 750 ℃ and the mechanism of preparing LiCoO2 by microwave heating is different from that by conventional heating. The electrochemical behaviors of samples were tested. As a result, the highest specific discharge capacity is 134.3 mAh/g and the coulomb efficiency is 92.56%.

  2. Organotrisulfide: A High Capacity Cathode Material for Rechargeable Lithium Batteries.

    Science.gov (United States)

    Wu, Min; Cui, Yi; Bhargav, Amruth; Losovyj, Yaroslav; Siegel, Amanda; Agarwal, Mangilal; Ma, Ying; Fu, Yongzhu

    2016-08-16

    An organotrisulfide (RSSSR, R is an organic group) has three sulfur atoms which could be involved in multi-electron reduction reactions; therefore it is a promising electrode material for batteries. Herein, we use dimethyl trisulfide (DMTS) as a model compound to study its redox reactions in rechargeable lithium batteries. With the aid of XRD, XPS, and GC-MS analysis, we confirm DMTS could undergo almost a 4 e(-) reduction process in a complete discharge to 1.0 V. The discharge products are primarily LiSCH3 and Li2 S. The lithium cell with DMTS catholyte delivers an initial specific capacity of 720 mAh g(-1) DMTS and retains 82 % of the capacity over 50 cycles at C/10 rate. When the electrolyte/DMTS ratio is 3:1 mL g(-1) , the reversible specific energy for the cell including electrolyte can be 229 Wh kg(-1) . This study shows organotrisulfide is a promising high-capacity cathode material for high-energy rechargeable lithium batteries. PMID:27411083

  3. Microstructure and properties of a Mo-CeO2 heated cathode material

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jiuxing; WAN Xiaofeng; LI Xiangbo; ZHOU Wenyuan; ZHOU Meiling

    2004-01-01

    The microstructure, mechanical properties, and electron-emission properties of a newly developed heated cath ode material Mo-CeO2 with 4.0% (mass fraction) of CeO2 were investigated. It is shown that the Mo-CeO2 cathode material possesses high tensile strength and good room-temperature ductility. After carbonized, the Mo-CeO2 cathode material has a higher zero field emission current density and a lower work function compared with the W-ThO2 cathode material.

  4. Nanocomposite Materials for Cathodes and Electrolytes in Lithium Batteries

    Institute of Scientific and Technical Information of China (English)

    F. Croce; C.R. Martin; B. Scrosati; L. Settimi; C. Sides

    2005-01-01

    @@ 1Introduction Lithium-ion batteries are today the power sources of choice far portable electronics, a multi-billion dollar market[1]. This outstanding success has spawned great international interest in applying this technology to more demanding systems, such as electric of hybrid vehicles[2]. However, to achieve full success in this area,new electrode materials, less expensive, more energetic and more compatible with the environment than the present ones, have to be identified. Accordingly, intense R&D are in progress to reach this goal and few variable alternatives to the original lithium-ion battery design, have been proposed. Particularly interesting is the olivine-structured LiFePO4 cathode developed by Goodenough and co-workers[3], which offers several appealing features, such as high, flat voltage profile and relatively high specific capacity, combined with low cost and low toxicity. However, LiFePO4 has one crucial disadvantage, i.e. its inherently low electric conductivity which reflects in the inability to deliver high capacity at high discharge rates. Such as poor rate capability has been the object of investigation by various groups who have proposed different approaches to overcome it, including carbon coating[4], nano-fibril textures[5], optimized synthesis procedures[6] and foreign metal doping[7].

  5. Synthesis, strctural and electrochemical characterizations of lithium- manganese- rich composite cathode materials for lithium ion batteries

    Science.gov (United States)

    Wang, Dapeng

    The electrification trend for transportation systems requires alternative cathode materials to LiCoO2 with improved safety, lowered cost and extended cycle life. Lithium- manganese- rich composite cathode materials, which can be presented in a two component notation as xLi2MnO3·(1-x)LiMO 2, (M= Ni, Co or Mn) have superior cost and energy density advantages. These cathode materials have shown success in laboratory scale experiments, but are still facing challenges such as voltage fade, moderate rate capacity and tap density for commercialization. The synthesis of precursors with high packing density and suitable physical properties is critical to achieve high energy density as well as the other acceptable electrochemical performance for the next generation lithium ion batteries. The aim of this study is to correlate the electrochemical properties of materials to their structural, morphological, and physical properties by coordinating the science of synthesis with the science of function, in order to enable the use of these compounds in vehicle technologies. Three different precursors including carbonate, hydroxide and oxalate were synthesized by co-precipitation reactions using continuous stirred tank reactor (CSTR) under various conditions. Research focused on areas such as nucleation and growth mechanisms, synthesis optimizations, and intrinsic limitations of each co-precipitation method. A combination of techniques such as PSA, BET, SEM, EDX FIB, TEM, Raman, FTIR, TGA-DSC, XRD, and ICP-MS, as well as electrochemical test methods such as cycling, CV, EIS and HPPC tests were used in correlation with each other in order to deepen our understanding to these materials. Related topics such as the composite structure formation process during the solid state reaction, lithium and nickel content effects on the cathode properties were also discussed. Additionally, the side reactions between the active materials and electrolyte as a result of the high charge potential were

  6. Chemical Extraction Preparation of Delithiated Cathode Materials of Li-ion Battery

    Institute of Scientific and Technical Information of China (English)

    YAN Shijian; ZHANG Mingang; CHAI Yuesheng; TIAN Wenhuai

    2009-01-01

    A method of conventional chemical reaction to prepare delithiated cathode materials of Li-ion battery was introduced.The cathode material of Li-ion battery was mixed with oxidizing agent Na_2S_2O_8 in water solution,and the solution was stirred continuously to make the chemical re-action proceed sufficiently,then the reaction product was filtered and finally the insoluble delithiated cathode material was obtained.A series of tests were conducted to verify the composition,crystal structure and electrochemical property of the delithiated cathode materials were all desirable.This method overcomes the shortcomings of battery charging preparation and chemical extraction prepa-ration employing other oxidizing agents.

  7. Advanced Cathode Material For High Energy Density Lithium-Batteries Project

    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...

  8. Hexagonal NiS nanobelts as advanced cathode materials for rechargeable Al-ion batteries.

    Science.gov (United States)

    Yu, Zhijing; Kang, Zepeng; Hu, Zongqian; Lu, Jianhong; Zhou, Zhigang; Jiao, Shuqiang

    2016-08-16

    Hexagonal NiS nanobelts served as novel cathode materials for rechargeable Al-ion batteries based on an AlCl3/[EMIm]Cl ionic liquid electrolyte system. The nano-banded structure of the materials can facilitate the electrolyte immersion and enhance Al(3+) diffusion. The hexagonal NiS nanobelt based cathodes exhibit high storage capacity, good cyclability and low overpotential. PMID:27487940

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

    OpenAIRE

    Libao Chen; Ming Zhang; Weifeng Wei

    2013-01-01

    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.

  10. 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.

  11. Development of suitable potting material for dispenser cathodes of a high power microwave tube

    International Nuclear Information System (INIS)

    Highlights: ► Potting material. ► Doped alumina. ► Non-shrinkable. ► Dispenser cathode. ► Microwave tube. - Abstract: The present study aims to develop suitable advanced potting material for modern high performance dispenser cathodes for high power microwave tube through refinement of the alumina microstructure by using suitable dopant. Calcium oxide was selected as a dopant material and the resultant materials were characterized by X-ray diffraction studies and the microstructure monitored by SEM study and EDX analysis. The shrinkage, thermal and electrical properties of the resultant material was evaluated to establish its suitability to function as an advanced potting material.

  12. Covalently Functionalized Graphene by Radical Polymers for Graphene-Based High-Performance Cathode Materials.

    Science.gov (United States)

    Li, Yongjun; Jian, Zukai; Lang, Meidong; Zhang, Chunming; Huang, Xiaoyu

    2016-07-13

    Polymer-functionalized graphene sheets play an important role in graphene-containing composite materials. Herein, functionalized graphene sheets covalently linked with radical polymer, graphene-graft-poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (G-g-PTMA), were prepared via surface-initiated atom transfer radical polymerization (SI-ATRP). A composite cathode with G-g-PTMA as major active material and reduced graphene oxide (RGO) as conductive additive was fabricated via a simple dispersing-depositing process, and this composite cathode exhibited a relatively high specific capacity up to 466 mAh g(-1) based on the mass of PTMA, which is much higher than the theoretical capacity of PTMA. This extraordinary electrochemical performance is attributed to the fast one-electron redox reaction of G-g-PTMA and surface Faradaic reaction of RGO boosted by G-g-PTMA, which suggested that G-g-PTMA sheets play a dual role in the composite materials, that is, on the one hand provided the fast one-electron redox reaction of PTMA and on the other hand worked as nanofiller for facilitating the surface Faradaic reaction-based lithium storage of RGO. PMID:27328986

  13. Recovery of cathode materials and Al from spent lithium-ion batteries by ultrasonic cleaning.

    Science.gov (United States)

    He, Li-Po; Sun, Shu-Ying; Song, Xing-Fu; Yu, Jian-Guo

    2015-12-01

    Cathode materials are difficult to separate from Al-foil substrates during the recycling of spent lithium-ion batteries (LIBs), because of the strong bonding force present. In this study, ultrasonic cleaning was used to separate and recycle these cathode materials. The mechanism of separation was ascribed to the dissolution of polyvinylidene fluoride (PVDF) and the cavitation caused by ultrasound. Based on this mechanism, the key parameters affecting the peel-off efficiency of cathode materials from Al foil was identified as solvent nature, temperature, ultrasonic power, and ultrasonic time. The peel-off efficiency of cathode materials achieved ∼ 99% under the optimized conditions of N-methyl-2-pyrrolidone (NMP) cleaning fluid, 70°C process temperature, 240 W ultrasonic power, and 90 min of ultrasonication. The cathode materials separated from Al foil displayed a low agglomeration degree, which is beneficial to the subsequent leaching process. Finally, a new, environmentally-sound process was proposed to efficiently recycle cathode materials and Al from spent LIBs, consisting of manual dismantling, ultrasonic cleaning, and picking.

  14. 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

    2016-08-01

    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. PMID:27060219

  15. Polymer/Transitonal Metal Oxides Nanocomposites as Cathode Materials for Rechargeable Lithium/Lithium lon Batteries

    Institute of Scientific and Technical Information of China (English)

    Hui Kang Wu

    2000-01-01

    The synthesis and properties of polymer/transition metal oxides nanocomposite material were reviewed.The new nanocomposite material(PPY)0.5/MoO3 prepared by a new method is described.The application of the nanocomposite materials as cathode material in rechargeable lithium/lithium ion batteries was explored.

  16. Electrochemical performance of LiFePO4 cathode material for Li-ion battery

    Institute of Scientific and Technical Information of China (English)

    LI Shuzhong; LI Chao; FAN Yanliang; XU Jiaqiang; WANG Tao; YANG Shuting

    2006-01-01

    In the search for improved materials for rechargeable lithium batteries, LiFePO4 offers interesting possibilities because of its low raw materials cost, environmental friendliness and safety. The main drawback with using the material is its poor electronic conductivity and this limitation has to be overcome. Here Al-doped LiFePO4/C composite cathode materials were prepared by a polymer-network synthesis technique. Testing of X-ray diffraction, charge-discharge, and cyclic voltammetry were carried out for its performance. Results show that Al-doped LiFePO4/C composite cathode materials have a high initial capacity, good cycle stability and excellent low temperature performance. The electrical conductivity of LiFePO4 material can be obviously improved by doping Al. The better electrochemical performances of Al-doped LiFePO4/C composite cathode materials have a connection with its conductivity.

  17. Characterization of Atomic and Electronic Structures of Electrochemically Active SOFC Cathode Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Blinn; Yongman Choi; Meilin Liu

    2009-08-11

    The objective of this project is to gain a fundamental understanding of the oxygen-reduction mechanism on mixed conducting cathode materials by means of quantum-chemical calculations coupled with direct experimental measurements, such as vibrational spectroscopy. We have made progress in the elucidation of the mechanisms of oxygen reduction of perovkite-type cathode materials for SOFCs using these quantum chemical calculations. We established computational framework for predicting properties such as oxygen diffusivity and reaction rate constants for adsorption, incorporation, and TPB reactions, and formulated predictions for LSM- and LSC-based cathode materials. We have also further developed Raman spectroscopy as well as SERS as a characterization tool for SOFC cathode materials. Raman spectroscopy was used to detect chemical changes in the cathode from operation conditions, and SERS was used to probe for pertinent adsorbed species in oxygen reduction. However, much work on the subject of unraveling oxygen reduction for SOFC cathodes remains to be done.

  18. Selenium and selenium-sulfur cathode materials for high-energy rechargeable magnesium batteries

    Science.gov (United States)

    Zhao-Karger, Zhirong; Lin, Xiu-Mei; Bonatto Minella, Christian; Wang, Di; Diemant, Thomas; Behm, R. Jürgen; Fichtner, Maximilian

    2016-08-01

    Magnesium (Mg) is an attractive metallic anode material for next-generation batteries owing to its inherent dendrite-free electrodeposition, high capacity and low cost. Here we report a new class of Mg batteries based on both elemental selenium (Se) and selenium-sulfur solid solution (SeS2) cathode materials. Elemental Se confined into a mesoporous carbon was used as a cathode material. Coupling the Se cathode with a metallic Mg anode in a non-nucleophilic electrolyte, the Se cathode delivered a high initial volumetric discharge capacity of 1689 mA h cm-3 and a reversible capacity of 480 mA h cm-3 was retained after 50 cycles at a high current density of 2 C. The mechanistic insights into the electrochemical conversion in Mg-Se batteries were investigated by microscopic and spectroscopic methods. The structural transformation of cyclic Se8 into chainlike Sen upon battery cycling was revealed by ex-situ Raman spectroscopy. In addition, the promising battery performance with a SeS2 cathode envisages the perspective of a series of SeSn cathode materials combining the benefits of both selenium and sulfur for high energy Mg batteries.

  19. Preparation of mesohollow and microporous carbon nanofiber and its application in cathode material for lithium–sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yuanhe; Gao, Mingxia, E-mail: gaomx@zju.edu.cn; Li, Xiang; Liu, Yongfeng; Pan, Hongge, E-mail: hgpan@zju.edu.cn

    2014-09-01

    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.

  20. Improved electrochemical performance of the Cr doped cathode materials for energy storage/conversion devices

    Science.gov (United States)

    Sangeeta, Agnihotri, Shruti; Arya, Anil; Sharma, A. L.

    2016-05-01

    Successful synthesis of a nanostructured Cr-doped LiFePO4 cathode material has been prepared by a sol-gel technique followed by a single step thermal treatment at 750° C for 12 hours. As olivine type LiFePO4 has already gained much attention due to its advantages over other cathode materials, doping of metal ion is done in the paper to improve its drawback of lower conductivity. FESEM couples with EDX were done to characterize the morphology and particle size of the materials. LiFe(1-x)CrxPO4 (x=0.1, 0.2, 0.3) materials have average particle size of 30 to 50 nm. EDX analysis confirmed the precursor used and also confirmed the presence of carbon which is in good agreement with chemical analysis result. Electrical conductivity of the prepared cathode materials is estimated of the order of 10-5 Scm-1 by AC impedance analysis. The energy density and power density of the cathode materials is improved drastically after addition of Cr as dopant. The estimated parameters appear at desirable value for use of materials as cathode in energy storage/conversion devices.

  1. Immobilization of a Metal-Nitrogen-Carbon Catalyst on Activated Carbon with Enhanced Cathode Performance in Microbial Fuel Cells.

    Science.gov (United States)

    Yang, Wulin; Logan, Bruce E

    2016-08-23

    Applications of microbial fuel cells (MFCs) are limited in part by low power densities mainly due to cathode performance. Successful immobilization of an Fe-N-C co-catalyst on activated carbon (Fe-N-C/AC) improved the oxygen reduction reaction to nearly a four-electron transfer, compared to a twoelectron transfer achieved using AC. With acetate as the fuel, the maximum power density was 4.7±0.2 W m(-2) , which is higher than any previous report for an air-cathode MFC. With domestic wastewater as a fuel, MFCs with the Fe-N-C/AC cathode produced up to 0.8±0.03 W m(-2) , which was twice that obtained with a Pt-catalyzed cathode. The use of this Fe-N-C/AC catalyst can therefore substantially increase power production, and enable broader applications of MFCs for renewable electricity generation using waste materials.

  2. On the dispersion of lithium-sulfur battery cathode materials effected by electrostatic and stereo-chemical factors of binders

    Science.gov (United States)

    Hong, Xiaoheng; Jin, Jun; Wen, Zhaoyin; Zhang, Sanpei; Wang, Qingsong; Shen, Chen; Rui, Kun

    2016-08-01

    Sodium carboxymethyl cellulose-styrene butadiene rubber (CMC-SBR), sodium alginate (SA) and LA132 are utilized as the polymer binders for the cathodes of Li-S batteries to study their dispersion mechanism on the cathode materials and the consequent influence on the performance of Li-S batteries. Zeta potential tests, differential scanning calorimetry analysis and calculations of the rotational barriers of the links of the polymer chains by General Atomic and Molecular Electronic Structure System (GAMESS) reveal that higher charge densities and better chain flexibility of the binders promise the dispersion of the downsized cathode materials. LA132 is found to have optimal characteristic for dispersing and stabilizing the cathode materials in aqueous environment. The cycling performance and SEM images of the cathodes demonstrate that cathodes with higher dispersion degree achieve higher discharge capacities. The electrochemical impedance spectroscopy (EIS) results further support that better dispersed cathodes have lower impedance resulting from their well established conducting frameworks.

  3. 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...

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Polk, James E., E-mail: james.e.polk@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States); Capece, Angela M. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States)

    2015-05-30

    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

  6. Studies on niobium triselenide cathode material for lithium rechargeable cells

    Science.gov (United States)

    Ratnakumar, B. V.; Ni, C. L.; Distefano, S.; Somoano, R. B.; Bankston, C. P.

    1988-01-01

    NbSe3 exhibits superior characteristics such as high capacity, high volumetric and gravimetric energy densities, and high discharge rate capability, as compared to other intercalating cathodes. This paper reports the preparation, characterization, and performance of NbSe3. Several electrochemical techniques, such as cyclic voltammetry, constant-current/constant-potential discharges, dc potentiodynamic scans, ac impedance, and ac voltammetry, have been used to give insight to the mechanisms of intercalation of three lithiums with NbSe3 and also into the rate determining process in the reduction of NbSe3.

  7. Nanoscale visualization of redox activity at lithium-ion battery cathodes.

    Science.gov (United States)

    Takahashi, Yasufumi; Kumatani, Akichika; Munakata, Hirokazu; Inomata, Hirotaka; Ito, Komachi; Ino, Kosuke; Shiku, Hitoshi; Unwin, Patrick R; Korchev, Yuri E; Kanamura, Kiyoshi; Matsue, Tomokazu

    2014-01-01

    Intercalation and deintercalation of lithium ions at electrode surfaces are central to the operation of lithium-ion batteries. Yet, on the most important composite cathode surfaces, this is a rather complex process involving spatially heterogeneous reactions that have proved difficult to resolve with existing techniques. Here we report a scanning electrochemical cell microscope based approach to define a mobile electrochemical cell that is used to quantitatively visualize electrochemical phenomena at the battery cathode material LiFePO4, with resolution of ~100 nm. The technique measures electrode topography and different electrochemical properties simultaneously, and the information can be combined with complementary microscopic techniques to reveal new perspectives on structure and activity. These electrodes exhibit highly spatially heterogeneous electrochemistry at the nanoscale, both within secondary particles and at individual primary nanoparticles, which is highly dependent on the local structure and composition. PMID:25399818

  8. Chemical compatibility study of melilite-type gallate solid electrolyte with different cathode materials

    Science.gov (United States)

    Mancini, Alessandro; Felice, Valeria; Natali Sora, Isabella; Malavasi, Lorenzo; Tealdi, Cristina

    2014-05-01

    Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La1.50Sr0.50Ga3O7.25 has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La0.8Sr0.2MnO3-d and La0.8Sr0.2Fe0.8Cu0.2O3-d and K2NiF4-type La2NiO4+d were selected as cathode materials. The results of this study allow identifying the most suitable electrode material to be used in combination with the melilite-type gallate electrolyte and set the basis for future work on this novel system.

  9. Critical parameters governing energy density of Li-storage cathode materials unraveled by confirmatory factor analysis

    Science.gov (United States)

    Sohn, Kee-Sun; Han, Su Cheol; Park, Woon Bae; Pyo, Myoungho

    2016-03-01

    Despite extensive effort during the past few decades, a comprehensive understanding of the key variables governing the electrochemical properties of cathode materials in Li-ion batteries is still far from complete. To elucidate the critical parameters affecting energy density (ED) and capacity (Q) retention in layer and spinel cathodes, we data-mine the existing experimental data via confirmatory factor analysis (CFA) based on a structural equation model (SEM), which is a proven, versatile tool in understanding complex problems in the social science. The data sets are composed of 18 and 15 parameters extracted from 38 layer and 33 spinel compounds, respectively. CFA reveals the irrelevance of Q retention to all the parameters we adopt, but it also reveals the sensitive variations of ED with specific parameters. We validate the usefulness of CFA in material science and pinpointed critical parameters for high-ED cathodes, hoping to suggest a new insight in materials design.

  10. Controlling the corrosion and cathodic activation of magnesium via microalloying additions of Ge

    Science.gov (United States)

    Liu, R. L.; Hurley, M. F.; Kvryan, A.; Williams, G.; Scully, J. R.; Birbilis, N.

    2016-06-01

    The evolution of corrosion morphology and kinetics for magnesium (Mg) have been demonstrated to be influenced by cathodic activation, which implies that the rate of the cathodic partial reaction is enhanced as a result of anodic dissolution. This phenomenon was recently demonstrated to be moderated by the use of arsenic (As) alloying as a poison for the cathodic reaction, leading to significantly improved corrosion resistance. The pursuit of alternatives to toxic As is important as a means to imparting a technologically safe and effective corrosion control method for Mg (and its alloys). In this work, Mg was microalloyed with germanium (Ge), with the aim of improving corrosion resistance by retarding cathodic activation. Based on a combined analysis herein, we report that Ge is potent in supressing the cathodic hydrogen evolution reaction (reduction of water) upon Mg, improving corrosion resistance. With the addition of Ge, cathodic activation of Mg subject to cyclic polarisation was also hindered, with beneficial implications for future Mg electrodes.

  11. Perovskites for energy applications. From cathode material for fuel cells to a gas separation membrane

    Energy Technology Data Exchange (ETDEWEB)

    Meulenberg, W.A.; Baumann, S.; Betz, M.; Buchkremer, H.P.; Stoever, D. [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energieforschung (IEF); Serra, J.M.; Vert, V.B. [Universidad Politecnica de Valencia (Spain). Inst. de Tecnologia Quimica

    2010-07-01

    Oxyfuel power plants are one possibility for Carbon Capture and Storage (CCS) using pure oxygen instead of air to combust a carbon containing fuel. This oxygen can be produced by ceramic membranes, which consist of a Mixed Ionic Electronic Conductor (MIEC). Appropriate materials for oxygen separation from air are perovskites transporting oxygen ions through oxygen vacancies in the crystal lattice. Perovskites show highest permeability in particular Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF) and offer a theoretical selectivity of 100%. However, perovskites with high permeability show in principle poor chemical stability e.g. in atmosphere containing CO{sub 2}, SO{sub 2}, or H{sub 2}O and particularly reducing conditions. Moreover the thermal and chemical expansion coefficient is very high, which makes the manufacturing of a gas-tight thin film on or joining to a material different from BSCF nearly impossible. Solid oxide fuel cells (SOFCs) are becoming promising candidates for highly efficient energy generation from conventional and biomass-derived fuels due to different reasons: (i) electricity can be obtained directly from a fuel; (ii) the sub-product is a high quality heat, usable in (micro) turbines and for building central heating (CHP) units; (iii) zero-emission operation is achieved when hydrogen is fuelled; (iv) SOFCs can operate besides H{sub 2} with hydrocarbons without extensive fuel purification and reforming; and (v) SOFCs are noiseless and modular. However, conventional SOFCs need to operate in the 800-1000 C temperature range. The reduction of the operating temperature below 700 C implies that the electrode polarization resistance of classical cathodes limits the whole cell operation, and consequently the performance is significantly reduced. Therefore, it is needed the development of new cathode materials with sufficient chemical stability and electrochemical activity to enable the operation at lower temperatures with

  12. 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.

  13. Mass distribution of sputtered cathode material in the reflex discharge along the magnetic field mirror configuration

    International Nuclear Information System (INIS)

    he paper is concerned with the distribution of cathode material sputtered under the action of the pulsed reflex discharge plasma and deposited on the anode surface (vacuum chamber) by means of a set of discrete receiving plates. Correlative relationship has been found between the weight gain increase of the receiving plates due to the deposition of cathode material (Ti) particles on them and the increasing magnetic field regions. The maximum possible sputtering yield Ycurr has been evaluated. The authors have deduced parametric dependences of the sputtering ratio on the power function exponent that determines the shape of the radial plasma-density profile, and also, on the magnetic field induction value

  14. Hollow nanoparticle cathode materials for sodium electrochemical cells and batteries

    Energy Technology Data Exchange (ETDEWEB)

    Shevchenko, Elena; Rajh, Tijana; Johnson, Christopher S.; Koo, Bonil

    2016-07-12

    A cathode comprises, in its discharged state, a layer of hollow .gamma.-Fe.sub.2O.sub.3 nanoparticles disposed between two layers of carbon nanotubes, and preferably including a metallic current collector in contact with one of the layers of carbon nanotubes. Individual particles of the hollow .gamma.-Fe.sub.2O.sub.3 nanoparticles comprise a crystalline shell of .gamma.-Fe.sub.2O.sub.3 including cation vacancies within the crystal structure of the shell (i.e., iron vacancies of anywhere between 3% to 90%, and preferably 44 to 77% of available octahedral iron sites). Sodium ions are intercalated within at least some of the cation vacancies within the crystalline shell of the hollow .gamma.-Fe.sub.2O.sub.3 nanoparticles.

  15. Atomic layer deposition of amorphous iron phosphates on carbon nanotubes as cathode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    A non-aqueous approach was developed to synthesize iron phosphate cathode materials by the atomic layer deposition (ALD) technique. Deposition of iron phosphate thin films was achieved on nitrogen-doped carbon nanotubes (NCNTs) by combining ALD subcycles of Fe2O3 (ferrocene-ozone) and POx (trimethyl phosphate-water) at 200 – 350 °C. The thickness of iron phosphate thin films depends linearly on the ALD cycle, indicating their self-limiting growth behavior. The growth per cycle of iron phosphate thin films was determined to be ∼ 0.2, 0.4, 0.6, and 0.5 Å, at 200, 250, 300, and 350 °C, respectively. Characterization by SEM, TEM, and HRTEM techniques revealed uniform and conformal coating of amorphous iron phosphates on the surface of NCNTs. XANES analysis confirmed Fe−O−P bonding in the iron phosphates prepared by ALD. Furthermore, electrochemical measurement verified the high electrochemical activity of the amorphous iron phosphate as a cathode material in lithium-ion batteries. It is expected that the amorphous iron phosphate prepared by this facile and cost-effective ALD approach will find applications in the next generation of lithium-ion batteries and thin film batteries as either cathode materials or surface coating materials

  16. Some aspects of carbon material application in auto-electron emission cathodes

    International Nuclear Information System (INIS)

    The detailed analysis of advantages and drawbacks of the carbon fibers and plane graphites with the developed surface application as cathode materials on the basis of the autoelectron emission is carried out. The original experimental results of studies on the carbon materials elementary composition, on the effect of thermal annealing on their structure and emission properties, on the decrease in the work yield by implantation of cesium therein are presented. The possibilities of radiation technologies by creating plane autoemission cathodes with the developed surface are considered; the dynamics of change in the emitting surface relief due to its bombardment by the residual gases low-energy ions is evaluated. Considerations on the advisability of realizing those or other structural solutions relative to the autoemission cathodes for various practical purposes are given

  17. Enhanced Oxygen and Hydroxide Transport in a Cathode Interface by Efficient Antibacterial Property of a Silver Nanoparticle-Modified, Activated Carbon Cathode in Microbial Fuel Cells.

    Science.gov (United States)

    Li, Da; Qu, Youpeng; Liu, Jia; Liu, Guohong; Zhang, Jie; Feng, Yujie

    2016-08-17

    A biofilm growing on an air cathode is responsible for the decreased performance of microbial fuel cells (MFCs). For the undesired biofilm to be minimized, silver nanoparticles were synthesized on activated carbon as the cathodic catalyst (Ag/AC) in MFCs. Ag/AC enhanced maximum power density by 14.6% compared to that of a bare activated carbon cathode (AC) due to the additional silver catalysis. After operating MFCs over five months, protein content on the Ag/AC cathode was only 38.3% of that on the AC cathode, which resulted in a higher oxygen concentration diffusing through the Ag/AC cathode. In addition, a lower pH increment (0.2 units) was obtained near the Ag/AC catalyst surface after biofouling compared to 0.8 units of the AC cathode, indicating that less biofilm on the Ag/AC cathode had a minor resistance on hydroxide transported from the catalyst layer interfaces to the bulk solution. Therefore, less decrements of the Ag/AC activity and MFC performance were obtained. This result indicated that accelerated transport of oxygen and hydroxide, benefitting from the antibacterial property of the cathode, could efficiently maintain higher cathode stability during long-term operation.

  18. Enhanced Oxygen and Hydroxide Transport in a Cathode Interface by Efficient Antibacterial Property of a Silver Nanoparticle-Modified, Activated Carbon Cathode in Microbial Fuel Cells.

    Science.gov (United States)

    Li, Da; Qu, Youpeng; Liu, Jia; Liu, Guohong; Zhang, Jie; Feng, Yujie

    2016-08-17

    A biofilm growing on an air cathode is responsible for the decreased performance of microbial fuel cells (MFCs). For the undesired biofilm to be minimized, silver nanoparticles were synthesized on activated carbon as the cathodic catalyst (Ag/AC) in MFCs. Ag/AC enhanced maximum power density by 14.6% compared to that of a bare activated carbon cathode (AC) due to the additional silver catalysis. After operating MFCs over five months, protein content on the Ag/AC cathode was only 38.3% of that on the AC cathode, which resulted in a higher oxygen concentration diffusing through the Ag/AC cathode. In addition, a lower pH increment (0.2 units) was obtained near the Ag/AC catalyst surface after biofouling compared to 0.8 units of the AC cathode, indicating that less biofilm on the Ag/AC cathode had a minor resistance on hydroxide transported from the catalyst layer interfaces to the bulk solution. Therefore, less decrements of the Ag/AC activity and MFC performance were obtained. This result indicated that accelerated transport of oxygen and hydroxide, benefitting from the antibacterial property of the cathode, could efficiently maintain higher cathode stability during long-term operation. PMID:27441786

  19. Development of suitable potting material for dispenser cathodes of a high power microwave tube

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Kalyan S.; Ghosh, Sumana; Dandapat, Nandadulal [Bio-Ceramics and Coating Division, CSIR - Central Glass and Ceramic Research Institute, 196, Raja S.C. Mullick Road, Kolkata 700 032, West Bengal (India); Datta, Someswar, E-mail: sdatta@cgcri.res.in [Bio-Ceramics and Coating Division, CSIR - Central Glass and Ceramic Research Institute, 196, Raja S.C. Mullick Road, Kolkata 700 032, West Bengal (India); Basu, Debabrata [Bio-Ceramics and Coating Division, CSIR - Central Glass and Ceramic Research Institute, 196, Raja S.C. Mullick Road, Kolkata 700 032, West Bengal (India); Raju, R.S. [Microwave Tubes Division, CSIR - Central Electronics Engineering Research Institute, Pilani 333031, Rajasthan (India)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Potting material. Black-Right-Pointing-Pointer Doped alumina. Black-Right-Pointing-Pointer Non-shrinkable. Black-Right-Pointing-Pointer Dispenser cathode. Black-Right-Pointing-Pointer Microwave tube. - Abstract: The present study aims to develop suitable advanced potting material for modern high performance dispenser cathodes for high power microwave tube through refinement of the alumina microstructure by using suitable dopant. Calcium oxide was selected as a dopant material and the resultant materials were characterized by X-ray diffraction studies and the microstructure monitored by SEM study and EDX analysis. The shrinkage, thermal and electrical properties of the resultant material was evaluated to establish its suitability to function as an advanced potting material.

  20. Synthesis, Characterization and Testing of Novel Anode and Cathode Materials for Li-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    White, Ralph E.; Popov, Branko N.

    2002-10-31

    During this program we have synthesized and characterized several novel cathode and anode materials for application in Li-ion batteries. Novel synthesis routes like chemical doping, electroless deposition and sol-gel method have been used and techniques like impedance, cyclic voltammetry and charge-discharge cycling have been used to characterize these materials. Mathematical models have also been developed to fit the experimental result, thus helping in understanding the mechanisms of these materials.

  1. A new candidate as the cathode material for intermediate and low temperature SOFCs

    Institute of Scientific and Technical Information of China (English)

    LI Song; SUN Xueli; WEN Zhongsheng; SUN Juncai

    2006-01-01

    In order to develop the new cathode materials suitable for intermediate and low temperature solid oxide fuel cells (IT/LTSOFCs), LaNi1-xFexO3(x=0.4-0.8) (LNF) materials were synthesized using coprecipitation method. Their structures and morphologies were investigated by XRD and SEM, and their electronic conductivities at different temperatures were measured by dc four terminal method. Fuel cells were fabricated to evaluate the electrochemical properties of the LNF materials as cathodes at different temperatures. The performance of 450-497 mW·cm-2 was obtained in the temperature region of 580-650 ℃ for the LaNi0.2Fe0.8O3 cathode, and of 209-227 mW·cm-2 at 400-500 ℃ for the LaNi0.4Fe0.6O3. The excellent fuel cell performances indicate that the LNF materials are good cathodes for IT/LTSOFCs.

  2. Submicron organic nanofiber devices with different anode-cathode materials: A simple approach

    DEFF Research Database (Denmark)

    Henrichsen, Henrik Hartmann; Sturm, Heinz; Bøggild, Peter;

    2010-01-01

    The authors present a simple general method for simultaneously producing tens of submicron electrode gaps with different cathode and anode materials on top of nanofibers, nanowires, and nanotubes, with an optional gap size variation. Using this method, an ensemble of para-hexaphenylene (p6P...

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

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, J.A.; Pratuch, S.M.; Belser, F.C. [Lawrence Livermore National Lab., CA (United States)

    1993-09-16

    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.

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

    International Nuclear Information System (INIS)

    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 LiCoO2, LiMn2O4, LiMnO2, LiV2O5 e LiFePO4. (author)

  5. Electrochemical performance of sulfur composite cathode materials for rechargeable lithium batteries

    Institute of Scientific and Technical Information of China (English)

    Feng Wu; Sheng Xian Wu; Ren Jie Chen; Shi Chen; Guo Qing Wang

    2009-01-01

    The structure and characteristic of carbon materials have a direct influence on the electrochemical performance of sulfur-carbon composite electrode materials for lithium-sulfur battery. In this paper, sulfur composite has been synthesized by heating a mixture of elemental sulfur and activated carbon, which is characterized as high specific surface area and microporous structure. The composite, contained 70% sulfur, as cathode in a lithium cell based on organic liquid electrolyte was tested at room temperature. It showed two reduction peaks at 2.05 V and 2.35 V, one oxidation peak at 2.4 V during cyclic voltammogram test. The initial discharge specific capacity was 1180.8 mAh g~(-1) and the utilization of electrochemically active sulfur was about 70.6% assuming a complete reaction to the product of Li_2S. The specific capacity still kept as high as 720.4 mAh g~(-1) after 60 cycles retaining 61% of the initial discharge capacity.

  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. An investigation of anode and cathode materials in photomicrobial fuel cells.

    Science.gov (United States)

    Schneider, Kenneth; Thorne, Rebecca J; Cameron, Petra J

    2016-02-28

    Photomicrobial fuel cells (p-MFCs) are devices that use photosynthetic organisms (such as cyanobacteria or algae) to turn light energy into electrical energy. In a p-MFC, the anode accepts electrons from microorganisms that are either growing directly on the anode surface (biofilm) or are free floating in solution (planktonic). The nature of both the anode and cathode material is critical for device efficiency. An ideal anode is biocompatible and facilitates direct electron transfer from the microorganisms, with no need for an electron mediator. For a p-MFC, there is the additional requirement that the anode should not prevent light from perfusing through the photosynthetic cells. The cathode should facilitate the rapid reaction of protons and oxygen to form water so as not to rate limit the device. In this paper, we first review the range of anode and cathode materials currently used in p-MFCs. We then present our own data comparing cathode materials in a p-MFC and our first results using porous ceramic anodes in a mediator-free p-MFC.

  8. Mitigating voltage fade in cathode materials by improving the atomic level uniformity of elemental distribution.

    Science.gov (United States)

    Zheng, Jianming; Gu, Meng; Genc, Arda; Xiao, Jie; Xu, Pinghong; Chen, Xilin; Zhu, Zihua; Zhao, Wenbo; Pullan, Lee; Wang, Chongmin; Zhang, Ji-Guang

    2014-05-14

    Lithium- 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 well understood. Here we report for the first time the mitigation of voltage and energy fade of LMR cathodes by improving the atomic level spatial uniformity of the chemical species. The results reveal that LMR cathodes (Li[Li0.2Ni0.2M0.6]O2) prepared by coprecipitation and sol-gel methods, which are dominated by a LiMO2 type R3̅m structure, show significant nonuniform Ni distribution at particle surfaces. In contrast, the LMR cathode prepared by a hydrothermal assisted method is dominated by a Li2MO3 type C2/m structure with minimal Ni-rich surfaces. The samples with uniform atomic level spatial distribution demonstrate much better capacity retention and much smaller voltage fade as compared to those with significant nonuniform Ni distribution. The fundamental findings on the direct correlation between the atomic level spatial distribution of the chemical species and the functional stability of the materials may also guide the design of other energy storage materials with enhanced stabilities.

  9. 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.

  10. Fe-N-C catalyst modified graphene sponge as a cathode material for lithium-oxygen battery

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ling, E-mail: yulingcug@126.com; Shen, Yue, E-mail: shenyue1213@mail.hust.edu.cn; Huang, Yunhui, E-mail: huangyh@mail.hust.edu.cn

    2014-05-15

    Highlights: • Hydrothermally-synthesized graphene sponge is excellent skeleton of Li-O{sub 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{sup −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.

  11. Fe-N-C catalyst modified graphene sponge as a cathode material for lithium-oxygen battery

    International Nuclear Information System (INIS)

    Highlights: • Hydrothermally-synthesized graphene sponge is excellent skeleton of Li-O2 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

  12. Facile electrochemical polymerization of polypyrrole film applied as cathode material in dual rotating disk photo fuel cell

    Science.gov (United States)

    Li, Kan; Zhang, Hongbo; Tang, Tiantian; Tang, Yanping; Wang, Yalin; Jia, Jinping

    2016-08-01

    Polypyrrole (PPy) film is synthesized on Ti substrate through electrochemical polymerization method and is applied as cathode material in a TiO2 NTs-PPy dual rotating disk photo fuel cell (PFC). The optimized PPy electrochemical polymerization is carried out using linear sweep voltammetry from 0 V to 1.2 V (vs. SCE) with scan rate of 0.1 V s-1, 100 circles. Sixty milliliter real textile wastewater with the initial COD and conductivity of 408 ± 6 mgO2 L-1 and 20180 μS cm-1 is treated in this PFC under UV irradiation. About 0.46 V open-circuit voltage (VOC) and 1.8-2.2 mA short-circuit current (JSC) are obtained. Due to the effective electron-hole separation effect, the COD removal rate is as high as 0.0055 min-1. Stable current and COD removal can be obtained at different output voltage. Two influence factors including rotating speed and pH are investigated. Better electricity generation performance and COD removal activity are achieved at high rotating speed and in acidic condition. In comparison with platinized cathode, though VOC is lower, similar JSC is measured. Considering the high cost of Pt, PPy is a promising alternative cathode material in PFC that can also generate electricity efficiently and stably.

  13. 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

  14. Long-Term Performance of Chemically and Physically Modified Activated Carbons in Air Cathodes of Microbial Fuel Cells

    KAUST Repository

    Zhang, Xiaoyuan

    2014-07-31

    © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Activated carbon (AC) is a low-cost and effective catalyst for oxygen reduction in air cathodes of microbial fuel cells (MFCs), but its performance must be maintained over time. AC was modified by three methods: 1)pyrolysis with iron ethylenediaminetetraacetic acid (AC-Fe), 2)heat treatment (AC-heat), and 3)mixing with carbon black (AC-CB). The maximum power densities after one month with these AC cathodes were 35% higher with AC-Fe (1410±50mW m-2) and AC-heat (1400±20mW m-2), and 16% higher with AC-CB (1210±30mW m-2) than for plain AC (1040±20mW m-2), versus 1270±50mW m-2 for a Pt control. After 16months, the Pt cathodes produced only 250±10mW m-2. However, the AC-heat and AC-CB cathodes still produced 960-970mW m-2, whereas plain AC produced 860±60mW m-2. The performance of the AC cathodes was restored to >85% of the initial maximum power densities by cleaning with a weak acid solution. Based on cost considerations among the AC materials, AC-CB appears to be the best choice for long-term performance.

  15. 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

  16. Single-Step Fabrication Using a Phase Inversion Method of Poly(vinylidene fluoride) (PVDF) Activated Carbon Air Cathodes for Microbial Fuel Cells

    KAUST Repository

    Yang, Wulin

    2014-10-14

    Air cathodes used in microbial fuel cells (MFCs) need to have high catalytic activity for oxygen reduction, but they must also be easy to manufacture, inexpensive, and watertight. A simple one-step, phase inversion process was used here to construct an inexpensive MFC cathode using a poly(vinylidene fluoride) (PVDF) binder and an activated carbon catalyst. The phase inversion process enabled cathode preparation at room temperatures, without the need for additional heat treatment, and it produced for the first time a cathode that did not require a separate diffusion layer to prevent water leakage. MFCs using this new type of cathode produced a maximum power density of 1470 ± 50 mW m–2 with acetate as a substrate, and 230 ± 10 mW m–2 with domestic wastewater. These power densities were similar to those obtained using cathodes made using more expensive materials or more complex procedures, such as cathodes with a polytetrafluoroethylene (PTFE) binder and a poly(dimethylsiloxane) (PDMS) diffusion layer, or a Pt catalyst. Even though the PVDF cathodes did not have a diffusion layer, they withstood up to 1.22 ± 0.04 m of water head (∼12 kPa) without leakage, compared to 0.18 ± 0.02 m for cathodes made using PTFE binder and PDMS diffusion layer. The cost of PVDF and activated carbon ($3 m–2) was less than that of the stainless steel mesh current collector ($12 m–2). PVDF-based AC cathodes therefore are inexpensive, have excellent performance in terms of power and water leakage, and they can be easily manufactured using a single phase inversion process at room temperature.

  17. 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

  18. 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.

  19. 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.

  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. Chemical compatibility study of melilite-type gallate solid electrolyte with different cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Mancini, Alessandro [INSTM R.U. and Department of Chemistry–Physical Chemistry Division, University of Pavia, Pavia I-27100 (Italy); Felice, Valeria; Natali Sora, Isabella [INSTM R.U. and Department of Engineering, University of Bergamo, Dalmine, Bergamo I-24044 (Italy); Malavasi, Lorenzo [INSTM R.U. and Department of Chemistry–Physical Chemistry Division, University of Pavia, Pavia I-27100 (Italy); Tealdi, Cristina, E-mail: cristina.tealdi@unipv.it [INSTM R.U. and Department of Chemistry–Physical Chemistry Division, University of Pavia, Pavia I-27100 (Italy)

    2014-05-01

    Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25} has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La{sub 0.8}Sr{sub 0.2}MnO{sub 3−d} and La{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−d} and K{sub 2}NiF{sub 4}-type La{sub 2}NiO{sub 4+d} were selected as cathode materials. The results of this study allow identifying the most suitable electrode material to be used in combination with the melilite-type gallate electrolyte and set the basis for future work on this novel system. - Graphical abstract: Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25} has been extensively investigated by means of X-ray powder diffraction. - Highlights: • Chemical compatibility between melilite-type gallate and cathodes for SOFCs up to 1573 K. • No reactivity observed between La{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}. • Reactivity observed between La{sub 0.80}Sr{sub 0.20}MnO{sub 3−d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}. • Significant reactivity observed between La{sub 2}NiO{sub 4+d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}.

  2. Chemical compatibility study of melilite-type gallate solid electrolyte with different cathode materials

    International Nuclear Information System (INIS)

    Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La1.50Sr0.50Ga3O7.25 has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La0.8Sr0.2MnO3−d and La0.8Sr0.2Fe0.8Cu0.2O3−d and K2NiF4-type La2NiO4+d were selected as cathode materials. The results of this study allow identifying the most suitable electrode material to be used in combination with the melilite-type gallate electrolyte and set the basis for future work on this novel system. - Graphical abstract: Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La1.50Sr0.50Ga3O7.25 has been extensively investigated by means of X-ray powder diffraction. - Highlights: • Chemical compatibility between melilite-type gallate and cathodes for SOFCs up to 1573 K. • No reactivity observed between La0.8Sr0.2Fe0.8Cu0.2O3−d and La1.50Sr0.50Ga3O7.25. • Reactivity observed between La0.80Sr0.20MnO3−d and La1.50Sr0.50Ga3O7.25. • Significant reactivity observed between La2NiO4+d and La1.50Sr0.50Ga3O7.25

  3. Layered cathode materials for lithium ion rechargeable batteries

    Science.gov (United States)

    Kang, Sun-Ho; Amine, Khalil

    2007-04-17

    A number of materials with the composition Li.sub.1+xNi.sub..alpha.Mn.sub..beta.Co.sub..gamma.M'.sub..delta.O.sub.2-- zF.sub.z (M'=Mg,Zn,Al,Ga,B,Zr,Ti) for use with rechargeable batteries, wherein x is between about 0 and 0.3, .alpha. is between about 0.2 and 0.6, .beta. is between about 0.2 and 0.6, .gamma. is between about 0 and 0.3, .delta. is between about 0 and 0.15, and z is between about 0 and 0.2. Adding the above metal and fluorine dopants affects capacity, impedance, and stability of the layered oxide structure during electrochemical cycling.

  4. Lead oxides as cathode materials for voltage-compatible lithium cells

    Energy Technology Data Exchange (ETDEWEB)

    Peraldo Bicelli, L.; Rivolta, B.; Bonino, F.; Maffi, S.; Malitesta, C.

    1986-06-01

    Yellow ..beta..-PbO (massicot) and ..beta..-PbO/sub 2/ (plattnerite) have been investigated as cathode materials in organic electrolyte lithium cells. The main characteristics and performance of these cells have been examined and the discharge mechanism discussed on the basis of X-ray data. The two oxides are particularly interesting as candidates for voltage-compatible lithium cells. They exhibit long voltage plateaux of appropriate values and appreciable specific capacities and energies.

  5. 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

    2015-05-05

    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.

  6. Selective Recovery of Lithium from Cathode Materials of Spent Lithium Ion Battery

    Science.gov (United States)

    Higuchi, Akitoshi; Ankei, Naoki; Nishihama, Syouhei; Yoshizuka, Kazuharu

    2016-10-01

    Selective recovery of lithium from four kinds of cathode materials, manganese-type, cobalt-type, nickel-type, and ternary-type, of spent lithium ion battery was investigated. In all cathode materials, leaching of lithium was improved by adding sodium persulfate (Na2S2O8) as an oxidant in the leaching solution, while the leaching of other metal ions (manganese, cobalt, and nickel) was significantly suppressed. Optimum leaching conditions, such as pH, temperature, amount of Na2S2O8, and solid/liquid ratio, for the selective leaching of lithium were determined for all cathode materials. Recovery of lithium from the leachate as lithium carbonate (Li2CO3) was then successfully achieved by adding sodium carbonate (Na2CO3) to the leachate. Optimum recovery conditions, such as pH, temperature, and amount of Na2CO3, for the recovery of lithium as Li2CO3 were determined for all cases. Purification of Li2CO3 was achieved by lixiviation in all systems, with purities of the Li2CO3 higher than 99.4%, which is almost satisfactory for the battery-grade purity of lithium.

  7. 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.

  8. 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.

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

    Science.gov (United States)

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

    2014-04-01

    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: 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.

  10. New High Capacity Cathode Materials for Rechargeable Li-ion Batteries: Vanadate-Borate Glasses

    Science.gov (United States)

    Afyon, Semih; Krumeich, Frank; Mensing, Christian; Borgschulte, Andreas; Nesper, Reinhard

    2014-11-01

    V2O5 based materials are attractive cathode alternatives due to the many oxidation state switches of vanadium bringing about a high theoretical specific capacity. However, significant capacity losses are eminent for crystalline V2O5 phases related to the irreversible phase transformations and/or vanadium dissolution starting from the first discharge cycle. These problems can be circumvented if amorphous or glassy vanadium oxide phases are employed. Here, we demonstrate vanadate-borate glasses as high capacity cathode materials for rechargeable Li-ion batteries for the first time. The composite electrodes of V2O5 - LiBO2 glass with reduced graphite oxide (RGO) deliver specific energies around 1000 Wh/kg and retain high specific capacities in the range of ~ 300 mAh/g for the first 100 cycles. V2O5 - LiBO2 glasses are considered as promising cathode materials for rechargeable Li-ion batteries fabricated through rather simple and cost-efficient methods.

  11. Synthesis and Characterization of LiCoxMn2-xO4 Cathode Materials

    Institute of Scientific and Technical Information of China (English)

    YAO Yaochun; DAI Yongnian; YANG Bin; MA Wenhui; Takayuki Watanabe

    2007-01-01

    LiCoxMn2-xO4 cathode materials for lithium ion batteries were synthesized by mechanical activation-solid state reaction at 750℃ for 24 h in air atmosphere, and their crystal structure, morphology, element composition and electrochemical performance were characterized with XRD, SEM, ICP-AES and charge-discharge test. The experimental results show that all samples have a single spinel structure, well formed crystal shape and uniformly particle size distribution. The lattice parameters of LiCoxMa2-xO4 decrease and the average oxidation states of manganese ions increase with an increase in Co content. Compared with pure LiMn2O4, the LiCoxMn2-xO4(x=0.03-0.12) samples show a lower special capacity, but their cycling life are improved. The capacity loss of LiCo0.09Mn1.91O4 and LiCo0.12Mn1.88O4 is only 0.95% ,respectively, after the 20th cycle. The improvement of the cycle performance is attributed to the substitution of Co at the Mn sites in the spinel structure, which suppresses the Jahn-Teller distortion and improves the structural stability.

  12. Investigation of the removing process of cathode material in micro-EDM using an atomistic-continuum model

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jianwen; Zhang, Guojun; Huang, Yu; Ming, Wuyi; Liu, Min; Huang, Hao, E-mail: huanghaohust1990@gmail.com

    2014-10-01

    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.

  13. Investigation of the removing process of cathode material in micro-EDM using an atomistic-continuum model

    International Nuclear Information System (INIS)

    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

  14. Ionothermal Synthesis of Lithium Iron Phosphate Composite Nanoparticles as a Cathode Material for Li-ion Batteries

    OpenAIRE

    Miller, Ian Jacob

    2014-01-01

    An affordable yet high performance LiFePO4/C cathode material has been synthesized through an ionothermal approach. The incorporation of the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate in a bath synthesis with iron chloride and lithium phosphate as precursors has allowed for the precipitation of crystalline LiFePO4 using significantly less temperature and less time than previous methods. Post sintering with starch has yield a crystalline cathode material with a 155 mAh/...

  15. Silver electrodeposition on the activated carbon air cathode for performance improvement in microbial fuel cells

    Science.gov (United States)

    Pu, Liangtao; Li, Kexun; Chen, Zhihao; Zhang, Peng; Zhang, Xi; Fu, Zhou

    2014-12-01

    The present work was to study silver electrodeposition on the activated carbon (AC) air cathode for performance improvement in microbial fuel cells (MFCs). The treated cathodes were proved to be effective to enhance the performance of MFCs. The maximum power density of MFC with silver electrodeposition time of 50 s (Ag-50) cathode was 1080 ± 60 mW m-2, 69% higher than the bare AC air cathode. X-ray photoelectron spectroscopy (XPS) results showed that zero-valent, monovalent and divalent silver were present to transform mutually, which illustrated that the oxygen reduction reaction (ORR) at the cathode took place through four-electron pathway. From electrochemical impedance spectroscopy (EIS) analysis, the electrodeposition method made the total resistance of the electrodes largely reduced. Meanwhile the deposited silver had no toxic effects on anode culture but inhibited the biofilm growth of the cathodes. This kind of antimicrobial efficient cathode, prepared with a simple, fast and economical method, was of good benefit to the performance improvement of MFCs.

  16. Ultrathin spinel membrane-encapsulated layered lithium-rich cathode material for advanced Li-ion batteries.

    Science.gov (United States)

    Wu, Feng; Li, Ning; Su, Yuefeng; Zhang, Linjing; Bao, Liying; Wang, Jing; Chen, Lai; Zheng, Yu; Dai, Liqin; Peng, Jingyuan; Chen, Shi

    2014-06-11

    Lack of high-performance cathode materials has become a technological bottleneck for the commercial development of advanced Li-ion batteries. We have proposed a biomimetic design and versatile synthesis of ultrathin spinel membrane-encapsulated layered lithium-rich cathode, a modification by nanocoating. The ultrathin spinel membrane is attributed to the superior high reversible capacity (over 290 mAh g(-1)), outstanding rate capability, and excellent cycling ability of this cathode, and even the stubborn illnesses of the layered lithium-rich cathode, such as voltage decay and thermal instability, are found to be relieved as well. This cathode is feasible to construct high-energy and high-power Li-ion batteries. PMID:24844948

  17. Deciphering the thermal behavior of lithium rich cathode material by in situ X-ray diffraction technique

    Science.gov (United States)

    Muhammad, Shoaib; Lee, Sangwoo; Kim, Hyunchul; Yoon, Jeongbae; Jang, Donghyuk; Yoon, Jaegu; Park, Jin-Hwan; Yoon, Won-Sub

    2015-07-01

    Thermal stability is one of the critical requirements for commercial operation of high energy lithium-ion batteries. In this study, we use in situ X-ray diffraction technique to elucidate the thermal degradation mechanism of 0.5Li2MnO3-0.5LiNi0.33Co0.33Mn0.33O2 lithium rich cathode material in the absence and presence of electrolyte to simulate the real life battery conditions and compare its thermal behavior with the commercial LiNi0.33Co0.33Mn0.33O2 cathode material. We show that the thermal induced phase transformations in delithiated lithium rich cathode material are much more intense compared to similar single phase layered cathode material in the presence of electrolyte. The structural changes in both cathode materials with the temperature rise follow different trends in the absence and presence of electrolyte between 25 and 600 °C. Phase transitions are comparatively simple in the absence of electrolyte, the fully charged lithium rich cathode material demonstrates better thermal stability by maintaining its phase till 379 °C, and afterwards spinel structure is formed. In the presence of electrolyte, however, the spinel structure appears at 207 °C, subsequently it transforms to rock salt type cubic phase at 425 °C with additional metallic, metal fluoride, and metal carbonate phases.

  18. Electricity generation and bivalent copper reduction as a function of operation time and cathode electrode material in microbial fuel cells

    Science.gov (United States)

    Wu, Dan; Huang, Liping; Quan, Xie; Li Puma, Gianluca

    2016-03-01

    The performance of carbon rod (CR), titanium sheet (TS), stainless steel woven mesh (SSM) and copper sheet (CS) cathode materials are investigated in microbial fuel cells (MFCs) for simultaneous electricity generation and Cu(II) reduction, in multiple batch cycle operations. After 12 cycles, the MFC with CR exhibits 55% reduction in the maximum power density and 76% increase in Cu(II) removal. In contrast, the TS and SSM cathodes at cycle 12 show maximum power densities of 1.7 (TS) and 3.4 (SSM) times, and Cu(II) removal of 1.2 (TS) and 1.3 (SSM) times higher than those observed during the first cycle. Diffusional resistance in the TS and SSM cathodes is found to appreciably decrease over time due to the copper deposition. In contrast to CR, TS and SSM, the cathode made with CS is heavily corroded in the first cycle, exhibiting significant reduction in both the maximum power density and Cu(II) removal at cycle 2, after which the performance stabilizes. These results demonstrate that the initial deposition of copper on the cathodes of MFCs is crucial for efficient and continuous Cu(II) reduction and electricity generation over prolonged time. This effect is closely associated with the nature of the cathode material. Among the materials examined, the SSM is the most effective and inexpensive cathode for practical use in MFCs.

  19. Solution-processed cathode interfacial layer materials for high-efficiency polymer solar cells

    Directory of Open Access Journals (Sweden)

    Biao Xiao

    2015-09-01

    Full Text Available Polymer solar cells (PSCs are a new type of renewable energy source currently being extensively investigated due to perceived advantages; such as being lightweight, low-cost and because of the unlimited materials resource. The power conversion efficiency of state-of-the-art PSCs has increased dramatically in the past few years, obtained mainly through the development of new electron donor polymers, acceptors, and novel device structures through the use of various electrode interfacial materials. In this short review, recent progress in solution-processed cathode interfacial layers that could significantly improve device performances is summarized and highlighted.

  20. Characterization of tantalum doped lanthanum strontium ferrite as cathode materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Natali Sora, Isabella, E-mail: isabella.natali-sora@unibg.it [INSTM R.U. Bergamo and Department of Engineering and Applied Sciences, University of Bergamo, Viale Marconi 5, Dalmine, BG 24044 (Italy); Felice, Valeria [INSTM R.U. Bergamo and Department of Engineering and Applied Sciences, University of Bergamo, Viale Marconi 5, Dalmine, BG 24044 (Italy); Zurlo, Francesca; Licoccia, Silvia; Di Bartolomeo, Elisabetta [Department of Chemical Science and Technologies & NAST Center University of Rome “Tor Vergata”, Via della Ricerca Scientifica, 00133 (Italy)

    2015-11-05

    The phase relations and crystal structures of La{sub 1−x}Sr{sub x}Fe{sub 1−y}Ta{sub y}O{sub 3} in the compositional range x = 0–0.60, y = 0–0.20 were investigated by powder X-ray diffraction (XRD). The formal concentration of Fe{sup 4+} in the La{sub 1−x}Sr{sub x}Fe{sub 1−y}Ta{sub y}O{sub 3±w} (LSFT) system was calculated and related to the electrical/electrochemical properties. To investigate the electrochemical behaviour as cathode material for SOFCs, impedance measurements were performed on LSFT/electrolyte/LSFT symmetrical cells by using La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2}O{sub 3}, (LSGM) as electrolyte material. The lowest area specific resistance (ASR), derived from the polarization resistance (R{sub p}), 1 Ω cm{sup 2} at 750 °C, was measured for the LSFT compound doped with x = 0.40 and y = 0.05. - Highlights: • The lowest area specific resistance was obtained with Sr = 0.40 and Ta = 0.05. • The activation energies E{sub a} are in the range of 1.3–1.6 eV. • The samples were single phase when Sr = 0, 0.20, 0.40, and 0.6 and Ta = 0.05. • A predictive trend of the electric conductivity is proposed.

  1. Diffusion layer characteristics for increasing the performance of activated carbon air cathodes in microbial fuel cells

    KAUST Repository

    Zhang, Xiaoyuan

    2016-01-01

    The characteristics of several different types of diffusion layers were systematically examined to improve the performance of activated carbon air cathodes used in microbial fuel cells (MFCs). A diffusion layer of carbon black and polytetrafluoroethylene (CB + PTFE) that was pressed onto a stainless steel mesh current collector achieved the highest cathode performance. This cathode also had a high oxygen mass transfer coefficient and high water pressure tolerance (>2 m), and it had the highest current densities in abiotic chronoamperometry tests compared to cathodes with other diffusion layers. In MFC tests, this cathode also produced maximum power densities (1610 ± 90 mW m−2) that were greater than those of cathodes with other diffusion layers, by 19% compared to Gore-Tex (1350 ± 20 mW m−2), 22% for a cloth wipe with PDMS (1320 ± 70 mW m−2), 45% with plain PTFE (1110 ± 20 mW m−2), and 19% higher than those of cathodes made with a Pt catalyst and a PTFE diffusion layer (1350 ± 50 mW m−2). The highly porous diffusion layer structure of the CB + PTFE had a relatively high oxygen mass transfer coefficient (1.07 × 10−3 cm s−1) which enhanced oxygen transport to the catalyst. The addition of CB enhanced cathode performance by increasing the conductivity of the diffusion layer. Oxygen mass transfer coefficient, water pressure tolerance, and the addition of conductive particles were therefore critical features for achieving higher performance AC air cathodes.

  2. Influence of cathode material on emission characteristics of field emitters for microelectronics devices

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Junzo; Tsuji, Hiroshi; Gotoh, Yashuhito [Kyoto Univ. (Japan)] [and others

    1993-03-01

    In order to find out the cathode material suitable to vacuum microelectronics devices, dependence of cathode material of field emitters was investigated with respect to the emission characteristics. Since the field emitters for vacuum microelectronics devices are fabricated by thin film processes, the characteristics of the electron emission from deposited materials should be examined. In the present study, a dozen materials were deposited onto the tungsten needle fabricated by well-controlled electrochemical etching. Measurement of the emission was performed at the pressure of 10{sup -9} Torr range. The current-voltage characteristics and the stability measurements revealed that the gold emitters indicated excellent properties: stable and high current at low extraction voltage. The effective surface work function and the effective emission area were evaluated from the Fowler-Nordheim theory, assuming that the emission area rapidly decreases with reducing the apex radius. From this analysis, it is clarified that the gold emitter had the lowest effective work function among the examined emitters. The results can be interpreted as that in order to obtain stable emission characteristics, materials with inert surface should be selected. 13 refs., 6 figs., 1 tab.

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

    Science.gov (United States)

    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 α-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 α-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 α-V2O5.

  4. Porous cathode optimization for lithium cells: Ionic and electronic conductivity, capacity, and selection of materials

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.-H.; Wang, C.-W.; Zhang, X. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States); Sastry, A.M. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States); Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States); Department of Material Science and Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States)

    2010-05-01

    Narrowing the gap between theoretical and actual capacity in key Li-based battery systems can be achieved through improvements in both electronic and ionic conductivities of materials, via addition of conductive species. Additives do, however, penalize both volumetric and gravimetric properties, and also limit liquid transport and high rate performance. In this work, we developed a technique to design and optimize cathode system based directly on the relationships among ionic and electronic conductivities and specific energy, for a range of commercially viable cathode electrochemistries and additives. Our results quantify trade-offs among ionic and electronic conductivity, and conductivity and specific energy. We also provide quantitative relationships for improved utilization and specific power, with higher specific energy. Finally, we provide quantitative guidance for the design of high energy density Li(Ni{sub 1/3}Co{sub 1/3}Mn{sub 1/3})O{sub 2} cells using conductive additives, and also provide guidelines for the design of cathode systems, based directly on solid and liquid phase transport limitations. Future work will focus on higher rates of performance, and will be based on analyses here. (author)

  5. Research on cathode material of Li-ion battery by yttrium doping

    Institute of Scientific and Technical Information of China (English)

    TIAN Yanwen; KANG Xiaoxue; LIU Liying; XU Chaqing; QU Tao

    2008-01-01

    Modification of LiFePO4, LiMn2O4 and Li1+xV3O8 by doping yttrium was investigated. The influences of doping Y on structure, morphology and electrochemical performance of cathode materials were investigated systematically. The results indicated that the mechanisms of Y doping in three cathode materials were different, so the influences on the material performance were different. The crystal structure of the three materials was not changed by Y doping. However, the crystal parameters were influenced. The crystal parameters of LiMn2O4 became smaller, and the interlayer distance of (100) crystal plane of Li1+xV3O8 was lengthened after Y doping. The grain size of Y-doped LiFePO4 became smaller and grain morphology became more regular than that of undoped LiFePO4. It indicated that Y doping had no influence on crystal particle and morphology of LiMn2O4. The morphology of Li1+xV3O8 became irregular and its size became larger with the increase of Y. For LiFePO4 and Li1+xV3O8, both the initial discharge capacities and the cyclic performance were improved by Y doping. For LiMn2O4, the cyclic performance became better and the initial discharge capacities declined with increasing Y doping.

  6. Rational design of novel cathode materials in solid oxide fuel cells using first-principles simulations

    Energy Technology Data Exchange (ETDEWEB)

    Choi, YongMan; Liu, Meilin [Center for Innovative Fuel Cell and Battery Technologies, School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, N.W., Atlanta, GA 30332 (United States); Lin, M.C. [Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA 30322 (United States); Center for Interdisciplinary Molecular Science, National Chiao Tung University, Hsinchu 30010 (China)

    2010-03-01

    The search for clean and renewable sources of energy represents one of the most vital challenges facing us today. Solid oxide fuel cells (SOFCs) are among the most promising technologies for a clean and secure energy future due to their high energy efficiency and excellent fuel flexibility (e.g., direct utilization of hydrocarbons or renewable fuels). To make SOFCs economically competitive, however, development of new materials for low-temperature operation is essential. Here we report our results on a computational study to achieve rational design of SOFC cathodes with fast oxygen reduction kinetics and rapid ionic transport. Results suggest that surface catalytic properties are strongly correlated with the bulk transport properties in several material systems with the formula of La{sub 0.5}Sr{sub 0.5}BO{sub 2.75} (where B = Cr, Mn, Fe, or Co). The predictions seem to agree qualitatively with available experimental results on these materials. This computational screening technique may guide us to search for high-efficiency cathode materials for a new generation of SOFCs. (author)

  7. Rational design of novel cathode materials in solid oxide fuel cells using first-principles simulations

    Science.gov (United States)

    Choi, YongMan; Lin, M. C.; Liu, Meilin

    The search for clean and renewable sources of energy represents one of the most vital challenges facing us today. Solid oxide fuel cells (SOFCs) are among the most promising technologies for a clean and secure energy future due to their high energy efficiency and excellent fuel flexibility (e.g., direct utilization of hydrocarbons or renewable fuels). To make SOFCs economically competitive, however, development of new materials for low-temperature operation is essential. Here we report our results on a computational study to achieve rational design of SOFC cathodes with fast oxygen reduction kinetics and rapid ionic transport. Results suggest that surface catalytic properties are strongly correlated with the bulk transport properties in several material systems with the formula of La 0.5Sr 0.5BO 2.75 (where B = Cr, Mn, Fe, or Co). The predictions seem to agree qualitatively with available experimental results on these materials. This computational screening technique may guide us to search for high-efficiency cathode materials for a new generation of SOFCs.

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

    International Nuclear Information System (INIS)

    LiFePO4 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 LiFePO4-based composite via hydrothermal method and the influence of rGO on electrical conductivity of LiFePO4−based composite by varying mass of rGO in composition. Vibration of LiFePO4-based composite was detected on Fourier Transform Infrared Spectroscopy (FTIR) spectra, while single phase of LiFePO4 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

  9. Synthesis and Structure Transformation of Orthorhombic LiMnO2 Cathode Materials by Sol-gel Method

    Institute of Scientific and Technical Information of China (English)

    Shixi ZHAO; Hanxing LIU; Qiang LI; ShiXi OUYANG

    2004-01-01

    Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel structure LiMn2O4and rock-salt structure Li2MnO3, whereas in argon single-phase orthorhombic LiMnO2 could obtain at the range of 750℃ to 920℃. The substitution of Mn by Zn2+ or Co3+ in LiMnO2 led to the structure of LiMnO2 transiting to α-LiFeO2. The results of electrochemical cycles indicated that the discharged capacity of orthorhombic-LiMnO2was smaller at the initial stages, then gradually increased with the increasing of cycle number, finally the capacity stabilized to certain value after about 10th cycles. This phenomenon reveals that there is an activation process for orthorhombic LiMnO2 cathode materials during electrochemical cycles, which is a phase transition process from orthorhombic LiMnO2 to tetragonal spinel Li2Mn2O4. The capacity of orthorhombic LiMnO2 synthesized at lower temperature is larger than that synthesized at high temperature.

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

    Science.gov (United States)

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

    2016-02-01

    LiFePO4 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 LiFePO4-based composite via hydrothermal method and the influence of rGO on electrical conductivity of LiFePO4-based composite by varying mass of rGO in composition. Vibration of LiFePO4-based composite was detected on Fourier Transform Infrared Spectroscopy (FTIR) spectra, while single phase of LiFePO4 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.

  11. Electrochemical behavior of LiFePO4 cathode materials in the presence of anion adsorbents

    International Nuclear Information System (INIS)

    The poor rate capability is a major problem of olivine-structured lithium iron phosphate (LFP) cathode material in lithium-ion batteries due to its low electric conductivity and sluggish lithium diffusion. Other than the custom strategies to solve this problem like carbon coating and nano-size treatment, we simply mixed LFP with some anion adsorbents, which can store anions from the electrolytes swiftly. The effect of anion adsorbents on the performance of LFP composite electrode has been investigated by cyclic voltammetric tests and the corresponding apparent lithium diffusion coefficients have been measured

  12. Studies on Spinel LiMn2O4 Cathode Material Synthesized from Different Mn Sources

    Institute of Scientific and Technical Information of China (English)

    唐致远; 冯季军; 彭亚宁

    2004-01-01

    The spinel LiMn2O4 cathode material was synthesized with the solid-state reaction method. Four manganese compounds including electrolytic manganese dioxide (EMD), MnCO3, Mn3O4 and nano-EMD were used as Mn sources while LiOH·H2O was used as the uniform Li source. The crystal structure characteristics of these samples produced were investigated by means of XRD, SEM, particle size distribution analysis and specific surface area testing. Their electrochemical properties were also studied by comparing their specific capacity, charge and discharge efficiency and cycle performance.

  13. 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.

  14. 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. PMID:26609636

  15. Nitrate-Melt Synthesized HT-LiCoO2 as a Superior Cathode-Material for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Mariyappan Sathiya

    2009-07-01

    Full Text Available An electrochemically-active high-temperature form of LiCoO2 (HT-LiCoO2is prepared by thermally decomposing its constituent metal-nitrates at 700 ºC. The synthetic conditions have been optimized to achieve improved performance with the HT-LiCoO2cathode in Li-ion batteries. For this purpose, the synthesized materials have been characterized by powder X-ray diffraction, scanning electron microscopy, and galvanostatic charge-discharge cycling. Cathodes comprising HT-LiCoO2 exhibit a specific capacity of 140 mAhg-1 with good capacity-retention over several charge-discharge cycles in the voltage range between 3.5 V and 4.2 V, and can sustain improved rate capability in contrast to a cathode constituting LiCoO2 prepared by conventional ceramic method. The nitrate-melt-decomposition method is also found effective for synthesizing Mg-/Al- doped HT-LiCoO2; these also are investigated as cathode materials for Li-ion batteries.

  16. Microwave synthesis of Li2FeSiO4 cathode materials for lithium-ion batteries

    Institute of Scientific and Technical Information of China (English)

    Zhong Dong Peng; Yan Bing Cao; Guo Rong Hu; Ke Du; Xu Guang Gao; Zheng Wei Xiao

    2009-01-01

    A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-type Li2FeSiO4 sample with uniform and fine particle sizes is successfully and fast synthesized by microwave heating at 700 ℃ in 12 min. And the obtained Li2FeSiO4 materials show better electrochemical performance and microstructure than those of Li2FeSiO4 sample by the conventional solid-state reaction.

  17. Synthesis and Electrochemical Performance of Spinel LiMn2O4-x(SO4)x Cathode Materials

    Institute of Scientific and Technical Information of China (English)

    CHEN,Zhao-Yong(陈召勇); HE,Yi(贺益); LI,Zhi-Jie(李志杰); GAO,Li-Zhen(高利珍); JIANG,Qi(江奇); YU,Zuo-Long(于作龙)

    2002-01-01

    The spinel LiMn2O4-x(SO4)x compound cathode materials were synthesized by solid-state reaction of the calculated amounts of LiOH@H2O,MnO2 and MnSO4.The results of the electrochemical test demonstrated that these materials exhibited excellent electrochemical properties.The highest reversible capacity of these series of cathode materials was~120mAh/g,and after 50 cycles,this reversible capacity was still around 116 mAh/g with nearly 100% reversible efficiency,which revealed that doped sulfate ion could improve the structural stability of spinel.

  18. Polycarbonyl(quinonyl) organic compounds as cathode materials for sustainable lithium ion batteries

    International Nuclear Information System (INIS)

    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 CO2 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

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

    Science.gov (United States)

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

    2016-10-01

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

  20. 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)

  1. Heteroaromatic organic compound with conjugated multi-carbonyl as cathode material for rechargeable lithium batteries

    Science.gov (United States)

    Lv, Meixiang; Zhang, Fen; Wu, Yiwen; Chen, Mujuan; Yao, Chunfeng; Nan, Junmin; Shu, Dong; Zeng, Ronghua; Zeng, Heping; Chou, Shu-Lei

    2016-04-01

    The heteroaromatic organic compound, N,N’-diphenyl-1,4,5,8-naphthalenetetra- carboxylic diimide (DP-NTCDI-250) as the cathode material of lithium batteries is prepared through a simple one-pot N-acylation reaction of 1,4,5,8-naphthalenetetra-carboxylic dianhydride (NTCDA) with phenylamine (PA) in DMF solution followed by heat treatment in 250 °C. The as prepared sample is characterized by the combination of elemental analysis, NMR, FT-IR, TGA, XRD, SEM and TEM. The electrochemical measurements show that DP-NTCDI-250 can deliver an initial discharge capacity of 170 mAh g‑1 at the current density of 25 mA g‑1. The capacity of 119 mAh g‑1 can be retained after 100 cycles. Even at the high current density of 500 mA g‑1, its capacity still reaches 105 mAh g‑1, indicating its high rate capability. Therefore, the as-prepared DP-NTCDI-250 could be a promising candidate as low cost cathode materials for lithium batteries.

  2. Synthesis of Co-Al-Cl LDH by cathodic material reprocessing from cellular phone batteries

    International Nuclear Information System (INIS)

    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 H2O2 1:1 (v/v) acid solution containing Co and Al (extracted from cathodic material composed of LiCoO2 and aluminum foil). These metals were precipitated in LiOH at pH 9 or 11, or NH4OH 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)

  3. Cobalt based layered perovskites as cathode material for intermediate temperature Solid Oxide Fuel Cells: A brief review

    Science.gov (United States)

    Pelosato, Renato; Cordaro, Giulio; Stucchi, Davide; Cristiani, Cinzia; Dotelli, Giovanni

    2015-12-01

    Nowadays, the cathode is the most studied component in Intermediate Temperature-Solid Oxide Fuel Cells (IT-SOFCs). Decreasing SOFCs operating temperature implies slow oxygen reduction kinetics and large polarization losses. Double perovskites with general formula REBaCo2O5+δ are promising mixed ionic-electronic conductors, offering a remarkable enhancement of the oxygen diffusivity and surface exchange respect to disordered perovskites. In this review, more than 250 compositions investigated in the literature were analyzed. The evaluation was performed in terms of electrical conductivity, Area Specific Resistance (ASR), chemical compatibility with electrolytes and Thermal Expansion Coefficient (TEC). The most promising materials have been identified as those bearing the mid-sized rare earths (Pr, Nd, Sm, Gd). Doping strategies have been analyzed: Sr doping on A site promotes higher electrical conductivity, but worsen ASR and TECs; B-site doping (Fe, Ni, Mn) helps lowering TECs, but is detrimental for the electrochemical properties. A promising boost of the electrochemical activity is obtained by simply introducing a slight Ba under-stoichiometry. Still, the high sensitivity of the electrochemical properties against slight changes in the stoichiometry hamper a conclusive comparison of all the investigated compounds. Opportunities for an improvement of double perovskite cathodes performance is tentatively foreseen in combining together the diverse effective doping strategies.

  4. Cathode material influence on the power capability and utilizable capacity of next generation lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Roscher, Michael A.; Sauer, Dirk Uwe [RWTH Aachen University, Electrochemical Energy Conversion and Storage Systems Group, Institute for Power Electronics and Electrical Drives (ISEA), 52066 Aachen (Germany); Vetter, Jens [BMW Group, 80788 Muenchen (Germany)

    2010-06-15

    Lithium-ion cells (Li-ion) comprising lithium iron phosphate (LiFePO{sub 4}) based cathode active material are a promising battery technology for future automotive applications and consumer electronics in terms of safety, cycle and calendar lifetime and cost. Those cells comprise flat open circuit voltage (OCV) characteristics and long-term load history dependent cell impedance. In this work the special electric characteristics of LiFePO{sub 4} based cells are elucidated, quantified and compared to Li-ion cells containing a competing cathode technology. Through pulse tests and partial cycle tests, performed with various olivine based cells, the cycling history dependency of the internal resistance and therefore on the power capability is shown. Hence, methods are illustrated to quantify this load history impact on the cells performance. Subsequently, methods to achieve a safe battery operation are elucidated. Furthermore strategies are given to obtain reliable information about the cells power capability, taking the mentioned properties into consideration. (author)

  5. Facile synthesis and performance of polypyrrole-coated sulfur nanocomposite as cathode materials for lithium/sulfur batteries

    Institute of Scientific and Technical Information of China (English)

    Guanghui Yuan; Haodong Wang

    2014-01-01

    In situ chemical oxidation polymerization of pyrrole on the surface of sulfur particles was carried out to synthesize a sulfur/polypyrrole (S/PPy) nanocomposite with core-shell structure. The composite was characterized by elemental analysis, X-ray diffraction, scanning/transmission electron microscopy, and electrochemical measurements. XRD and FTIR results showed that sulfur well dispersed in the core-shell structure and PPy structure was successfully obtained via in situ oxidative polymerization of pyrrole on the surface of sulfur particles. TEM observation revealed that PPy was formed and fixed to the surface of sulfur nanoparticle after polymerization, developing a well-defined core-shell structure and the thickness of PPy coating layer was in the range of 20-30 nm. In the composite, PPy worked as a conducting matrix as well as a coating agent, which confined the active materials within the electrode. Consequently, the as prepared S/PPy composite cathode exhibited good cycling and rate performances for rechargeable lithium/sulfur batteries. The resulting cell containing S/PPy composite cathode yields a discharge capacity of 1039 mAh·g-1 at the initial cycle and retains 59%of this value over 50 cycles at 0.1 C rate. At 1 C rate, the S/PPy composite showed good cycle stability, and the discharge capacity was 475 mAh·g-1 after 50 cycles.

  6. Nonactivated and activated biochar derived from bananas as alternative cathode catalyst in microbial fuel cells.

    Science.gov (United States)

    Yuan, Haoran; Deng, Lifang; Qi, Yujie; Kobayashi, Noriyuki; Tang, Jiahuan

    2014-01-01

    Nonactivated and activated biochars have been successfully prepared by bananas at different thermotreatment temperatures. The activated biochar generated at 900°C (Biochar-act900) exhibited improved oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performances in alkaline media, in terms of the onset potential and generated current density. Rotating disk electron result shows that the average of 2.65 electrons per oxygen molecule was transferred during ORR of Biochar-act900. The highest power density of 528.2 mW/m(2) and the maximum stable voltage of 0.47 V were obtained by employing Biochar-act900 as cathode catalyst, which is comparable to the Pt/C cathode. Owning to these advantages, it is expected that the banana-derived biochar cathode can find application in microbial fuel cell systems.

  7. Nonactivated and Activated Biochar Derived from Bananas as Alternative Cathode Catalyst in Microbial Fuel Cells

    Directory of Open Access Journals (Sweden)

    Haoran Yuan

    2014-01-01

    Full Text Available Nonactivated and activated biochars have been successfully prepared by bananas at different thermotreatment temperatures. The activated biochar generated at 900°C (Biochar-act900 exhibited improved oxygen reduction reaction (ORR and oxygen evolution reaction (OER performances in alkaline media, in terms of the onset potential and generated current density. Rotating disk electron result shows that the average of 2.65 electrons per oxygen molecule was transferred during ORR of Biochar-act900. The highest power density of 528.2 mW/m2 and the maximum stable voltage of 0.47 V were obtained by employing Biochar-act900 as cathode catalyst, which is comparable to the Pt/C cathode. Owning to these advantages, it is expected that the banana-derived biochar cathode can find application in microbial fuel cell systems.

  8. 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.

  9. 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...... The Electrochemical Society. S0013-4651(00)04-075-1. All rights reserved....

  10. 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.

  11. 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).

  12. Use of Pyrolyzed Iron Ethylenediaminetetraacetic Acid Modified Activated Carbon as Air–Cathode Catalyst in Microbial Fuel Cells

    KAUST Repository

    Xia, Xue

    2013-08-28

    Activated carbon (AC) is a cost-effective catalyst for the oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). To enhance the catalytic activity of AC cathodes, AC powders were pyrolyzed with iron ethylenediaminetetraacetic acid (FeEDTA) at a weight ratio of FeEDTA:AC = 0.2:1. MFCs with FeEDTA modified AC cathodes and a stainless steel mesh current collector produced a maximum power density of 1580 ± 80 mW/m2, which was 10% higher than that of plain AC cathodes (1440 ± 60 mW/m 2) and comparable to Pt cathodes (1550 ± 10 mW/m2). Further increases in the ratio of FeEDTA:AC resulted in a decrease in performance. The durability of AC-based cathodes was much better than Pt-catalyzed cathodes. After 4.5 months of operation, the maximum power density of Pt cathode MFCs was 50% lower than MFCs with the AC cathodes. Pyridinic nitrogen, quaternary nitrogen and iron species likely contributed to the increased activity of FeEDTA modified AC. These results show that pyrolyzing AC with FeEDTA is a cost-effective and durable way to increase the catalytic activity of AC. © 2013 American Chemical Society.

  13. Metal segregation in hierarchically structured cathode materials for high-energy lithium batteries

    Science.gov (United States)

    Lin, Feng; Nordlund, Dennis; Li, Yuyi; Quan, Matthew K.; Cheng, Lei; Weng, Tsu-Chien; Liu, Yijin; Xin, Huolin L.; Doeff, Marca M.

    2016-01-01

    In technologically important LiNi1-x-yMnxCoyO2 cathode materials, surface reconstruction from a layered to a rock-salt structure is commonly observed under a variety of operating conditions, particularly in Ni-rich compositions. This phenomenon contributes to poor high-voltage cycling performance, impeding attempts to improve the energy density by widening the potential window at which these electrodes operate. Here, using advanced nano-tomography and transmission electron microscopy techniques, we show that hierarchically structured LiNi0.4Mn0.4Co0.2O2 spherical particles, made by a simple spray pyrolysis method, exhibit local elemental segregation such that surfaces are Ni-poor and Mn-rich. The tailored surfaces result in superior resistance to surface reconstruction compared with those of conventional LiNi0.4Mn0.4Co0.2O2, as shown by soft X-ray absorption spectroscopy experiments. The improved high-voltage cycling behaviour exhibited by cells containing these cathodes demonstrates the importance of controlling LiNi1-x-yMnxCoyO2 surface chemistry for successful development of high-energy lithium ion batteries.

  14. Mitigating Voltage Decay of Li-Rich Cathode Material via Increasing Ni Content for Lithium-Ion Batteries.

    Science.gov (United States)

    Shi, Ji-Lei; Zhang, Jie-Nan; He, Min; Zhang, Xu-Dong; Yin, Ya-Xia; Li, Hong; Guo, Yu-Guo; Gu, Lin; Wan, Li-Jun

    2016-08-10

    Li-rich layered materials have been considered as the most promising cathode materials for future high-energy-density lithium-ion batteries. However, they suffer from severe voltage decay upon cycling, which hinders their further commercialization. Here, we report a Li-rich layered material 0.5Li2MnO3·0.5LiNi0.8Co0.1Mn0.1O2 with high nickel content, which exhibits much slower voltage decay during long-term cycling compared to conventional Li-rich materials. The voltage decay after 200 cycles is 201 mV. Combining in situ X-ray diffraction (XRD), ex situ XRD, ex situ X-ray photoelectron spectroscopy, and scanning transmission electron microscopy, we demonstrate that nickel ions act as stabilizing ions to inhibit the Jahn-Teller effect of active Mn(3+) ions, improving d-p hybridization and supporting the layered structure as a pillar. In addition, nickel ions can migrate between the transition-metal layer and the interlayer, thus avoiding the formation of spinel-like structures and consequently mitigating the voltage decay. Our results provide a simple and effective avenue for developing Li-rich layered materials with mitigated voltage decay and a long lifespan, thereby promoting their further application in lithium-ion batteries with high energy density. PMID:27437556

  15. Cation mixing (Li0.5Fe0.5)2SO4F cathode material for lithium-ion batteries

    Institute of Scientific and Technical Information of China (English)

    Sun Yang; Liu Lei; Dong Jin-Ping; Zhang Bin; Huang Xue-Jie

    2011-01-01

    We study the crystal structure of a triplite-structured (Li0.5Fe0.5)SO4F with full Li+/Fe2+ mixing.This promising polyanion cathode material for lithium-ion batteries operates at 3.9 V versus Li+/Li with a theoretical capacity of 151 mAh/g.Its unique cation mixing structure does not block the Li+ diffusion and results in a small lattice volume change during the charge/discharge process.The calculations show that it has a three-dimensional network for Li-ion migration with an activation energy ranging from 0.53 eV to 0.68 eV,which is comparable with that in LiFePO4 with only one-dimensional channels.This work suggests that further exploring cathode materials with full cation mixing for Li-ion batteries will be valuable.

  16. A method for making an active cathode mass for an element with a liquid, anhydrous electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Indzima, T.; Morita, A.

    1983-07-14

    Powder of fluorinated carbon, produced as a result of a reaction between gaseous F2 and carbon powder in the presence of gaseous 02, is used as the active cathode mass in the element. The bulk volume of 02 is 3 percent with respect to the gaseous F2. The element with the lithium anode has good discharge characteristics.

  17. Enhanced Activated Carbon Cathode Performance for Microbial Fuel Cell by Blending Carbon Black

    KAUST Repository

    Zhang, Xiaoyuan

    2014-02-04

    Activated carbon (AC) is a useful and environmentally sustainable catalyst for oxygen reduction in air-cathode microbial fuel cells (MFCs), but there is great interest in improving its performance and longevity. To enhance the performance of AC cathodes, carbon black (CB) was added into AC at CB:AC ratios of 0, 2, 5, 10, and 15 wt % to increase electrical conductivity and facilitate electron transfer. AC cathodes were then evaluated in both MFCs and electrochemical cells and compared to reactors with cathodes made with Pt. Maximum power densities of MFCs were increased by 9-16% with CB compared to the plain AC in the first week. The optimal CB:AC ratio was 10% based on both MFC polarization tests and three electrode electrochemical tests. The maximum power density of the 10% CB cathode was initially 1560 ± 40 mW/m2 and decreased by only 7% after 5 months of operation compared to a 61% decrease for the control (Pt catalyst, 570 ± 30 mW/m2 after 5 months). The catalytic activities of Pt and AC (plain or with 10% CB) were further examined in rotating disk electrode (RDE) tests that minimized mass transfer limitations. The RDE tests showed that the limiting current of the AC with 10% CB was improved by up to 21% primarily due to a decrease in charge transfer resistance (25%). These results show that blending CB in AC is a simple and effective strategy to enhance AC cathode performance in MFCs and that further improvement in performance could be obtained by reducing mass transfer limitations. © 2014 American Chemical Society.

  18. Modeling study of a Li–O2 battery with an active cathode

    International Nuclear Information System (INIS)

    In this study, a new organic lithium oxygen (Li–O2) battery structure is proposed to enhance battery capacity. The electrolyte is forced to recirculate through the cathode and then saturated with oxygen in a tank external to the battery. The forced convection enhances oxygen transport and alleviates the problem of electrode blockage during discharge. A two dimensional, transient, non-isothermal simulation model is developed to study the heat and mass transfer within the battery and validate the proposed design. Results show that this novel active cathode design improves the battery capacity at all discharge current densities. The capacity of the Li–O2 battery is increased by 15.5 times (from 12.2 mAh g−1 to 201 mAh g−1) at the discharge current of 2.0 mA cm−2 when a conventional passive electrode is replaced by the newly designed active electrode. Furthermore, a cathode with non-uniform porosity is suggested and simulation results show that it can reach a higher discharge capacity without decreasing its power density. Detailed mass transport processes in the battery are also studied. - Highlights: • Electrolyte is circulated through the cathode and externally saturated with oxygen. • A two-dimensional, transient, non-isothermal model is developed for a Li–O2 battery. • The new design's capacity can be 15.5 times that of a battery with passive cathode. • A cathode with non-uniform porosity is proposed to further enhance battery capacity

  19. High electrochemical properties of graphene nanoribbons-hybridized manganese dioxide as cathode material for lithium battery

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiangyue; Fan, Zihan; Lin, Cunli; Jia, Lina; Lin, Baiwei; Wang, Jiaqi; Hu, Xiaolin, E-mail: linamethyst@fzu.edu.cn; Zhuang, Naifeng, E-mail: nfzhuang@fzu.edu.cn [Fuzhou University, College of Chemistry (China)

    2015-02-15

    Manganese dioxide crystallite and its composite hybridized with graphene nanoribbons (GNRs) are prepared by hydrothermal method. The effects of reaction temperature and time, surfactant, and reducing Mn resource are discussed. As the cathode material for Li battery, γ-MnO{sub 2} nanowire/nanorod hybridizing with (GNRs) (γ-MnO{sub 2}/GNRs) shows a higher discharge specific capacity than it covering with carbon nanotubes or graphene sheets. In addition, the discharge specific capacity of γ-MnO{sub 2}/GNRs is much higher than those of pure β-MnO{sub 2} and compact β-MnO{sub 2}/GNRs. The effects of crystal size, morphology, and GNR hybrid on the discharge specific capacity are discussed.

  20. PAM Templating Mechanism for Synthesis of A Novel LiFePO4 Cathode Material

    Institute of Scientific and Technical Information of China (English)

    YANG Shu-ting; ZHAO Na-hong; DONG Hong-yu; YUE Hong-yun; YANG Jin-xin

    2005-01-01

    A novel templated LiFePO4 cathode material was prepared with linear polyacrylamide, which exhibited excellent electrochemical properties, such as a 109.3 mA·h/g capacity at a rate of C/3 and a 120 mA·h/g capacity at a rate of C/6 as well as a good cycliability. We proposed the templating mechanism based upon the precursors' TG-DTA curves, X-ray diffraction patterns and FTIR spectra of the samples at different temperatures. A tapping-mode atomic force microscope was used to investigate the surfaces of the end products. We found that the polyacrylamide template produced metal organic compounds in the cross-linked gel precursor, and thereby modified the crystallization and particle surfaces during calcining. The template was "removed" in the end, which was partially pyrolyzed into the spiral carbon to form a conductive network with nanocrystalline LiFePO4 highly monodispersed in it.

  1. Synthesis Of Fe Doped LiMn2O4 Cathode Materials For Li Battery By Solid State Reaction

    Directory of Open Access Journals (Sweden)

    Horata N.

    2015-06-01

    Full Text Available LiFe0.1Mn1.9O4 is expected as a cathode material for the rechargeable lithium-ion batteries. LiMn2O4 has been received attention because this has advantages such as low cost and low toxicity compared with other cathode materials of LiCoO2 and LiNiO2. However, LiMn2O4 has some problems such as small capacity and no long life. LiMn2O4 is phase transformation at around human life temperature. One of the methods to overcome this problem is to stabilize the spinel structure by substituting Mn site ion in LiMn2O4 with transition metals (Al, Mg, Ti, Ni, Fe, etc.. LiFe0.1Mn1.9O4 spinel was synthesized from Li2CO3, Fe2O3 and MnO2 powder. The purpose of this study is to report the optimal condition of Fe doped LiFe0.1Mn1.9O4. Li2CO3, Fe2O3, and MnO2 mixture powder was heated up to 1173 K by TG-DTA. Li2CO3 was thermal decomposed, and CO2 gas evolved, and formed Li2O at about 800 K. LiFe0.1Mn1.9O4 was synthesized from a consecutive reaction Li2O, Fe2O3 and MnO2 at 723 ~ 1023 K. Active energy is calculated to 178 kJmol−1 at 723 ~ 1023 K. The X-ray powder diffraction pattern of the LiFe0.1Mn1.9O4 heated mixture powder at 1023 K for 32 h in air flow was observed.

  2. 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. PMID:26413683

  3. 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.

  4. Aqueous Solution Processed Photoconductive Cathode Interlayer for High Performance Polymer Solar Cells with Thick Interlayer and Thick Active Layer.

    Science.gov (United States)

    Nian, Li; Chen, Zhenhui; Herbst, Stefanie; Li, Qingyuan; Yu, Chengzhuo; Jiang, Xiaofang; Dong, Huanli; Li, Fenghong; Liu, Linlin; Würthner, Frank; Chen, Junwu; Xie, Zengqi; Ma, Yuguang

    2016-09-01

    An aqueous-solution-processed photoconductive cathode interlayer is developed, in which the photoinduced charge transfer brings multiple advantages such as increased conductivity and electron mobility, as well as reduced work function. Average power conversion efficiency over 10% is achieved even when the thickness of the cathode interlayer and active layer is up to 100 and 300 nm, respectively.

  5. An efficient electrocatalyst as cathode material for solid oxide fuel cells: BaFe0·95Sn0·05O3-δ

    Science.gov (United States)

    Dong, Feifei; Ni, Meng; He, Wei; Chen, Yubo; Yang, Guangming; Chen, Dengjie; Shao, Zongping

    2016-09-01

    The B-site substitution with the minor amount of tin in BaFeO3-δ parent oxide is expected to stabilize a single perovskite lattice structure. In this study, a composition of BaFe0·95Sn0·05O3-δ (BFS) as a new cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) is synthesized and characterized. Special attention is paid to the exploration of some basic properties including phase structure, oxygen non-stoichiometry, electrical conductivity, oxygen bulk diffusion coefficient, and surface exchange coefficient, which are of significant importance to the electrochemical activity of cathode materials. BFS holds a single cubic perovskite structure over temperature range of cell operation, determined by in-situ X-ray diffraction and scanning transmission electron microscope. A high oxygen vacancy concentration at cell operating temperatures is observed by combining thermo-gravimetric data and iodometric titration result. Furthermore, electrical conductivity relaxation measurement illustrates the fast oxygen bulk diffusion and surface exchange kinetics. Accordingly, testing cells based on BFS cathode material demonstrate the low polarization resistance of 0.033 Ω cm2 and high peak power density of 1033 mW cm-2 at 700 °C, as well as a relatively stable long-term operation for ∼300 h. The results obtained suggest that BFS perovskite oxide holds a great promise as an oxygen reduction electrocatalyst for IT-SOFCs.

  6. 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.

  7. 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, B.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 atten

  8. A new cathode material for LiCu{sub 2}O{sub 2} for secondary lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, M. M. E.; Hassan, M. S.; Arof, A. K. [Univ . of Malaya, Institute of Postgraduate Studies and Research, Kuala Lumpur, (Malaysia); Daud, J. [National Univ. of Malaysia, Dept. of Chemistry, Bangi (Malaysia)

    2000-01-01

    Synthesis of a lithium copper oxide material at a relatively low temperature, using the sol-gel method is described, This material is suspected to be a suitable insertion cathode material in lithium. Batteries based on insertion electrodes are said to be safe, less toxic, and easily prepared. Subjecting the product to X-ray analysis confirmed it to be LiCu{sub 2}O{sub 2}. A cell was assembled using LiCu{sub 2}O{sub 2} as the cathode material and Cu{sub 2}O as the anode material. On charging the cell for 1.5 hours at 200 mA, the cell delivered only 15 per cent of its total capacity. The poor performance of the cell is attributed to the low volumetric capacity of cuprous oxide which could not accommodate high lithium intercalation. 24 refs., 8 figs.

  9. Surface reconstruction and chemical evolution of stoichiometric layered cathode materials for lithium-ion batteries.

    Science.gov (United States)

    Lin, Feng; Markus, Isaac M; Nordlund, Dennis; Weng, Tsu-Chien; Asta, Mark D; Xin, Huolin L; Doeff, Marca M

    2014-01-01

    The present study sheds light on the long-standing challenges associated with high-voltage operation of LiNi(x)Mn(x)Co(1-2x)O2 cathode materials for lithium-ion batteries. Using correlated ensemble-averaged high-throughput X-ray absorption spectroscopy and spatially resolved electron microscopy and spectroscopy, here we report structural reconstruction (formation of a surface reduced layer, to transition) and chemical evolution (formation of a surface reaction layer) at the surface of LiNi(x)Mn(x)Co(1-2x)O2 particles. These are primarily responsible for the prevailing capacity fading and impedance buildup under high-voltage cycling conditions, as well as the first-cycle coulombic inefficiency. It was found that the surface reconstruction exhibits a strong anisotropic characteristic, which predominantly occurs along lithium diffusion channels. Furthermore, the surface reaction layer is composed of lithium fluoride embedded in a complex organic matrix. This work sets a refined example for the study of surface reconstruction and chemical evolution in battery materials using combined diagnostic tools at complementary length scales. PMID:24670975

  10. Surface reconstruction and chemical evolution of stoichiometric layered cathode materials for lithium-ion batteries.

    Science.gov (United States)

    Lin, Feng; Markus, Isaac M; Nordlund, Dennis; Weng, Tsu-Chien; Asta, Mark D; Xin, Huolin L; Doeff, Marca M

    2014-03-27

    The present study sheds light on the long-standing challenges associated with high-voltage operation of LiNi(x)Mn(x)Co(1-2x)O2 cathode materials for lithium-ion batteries. Using correlated ensemble-averaged high-throughput X-ray absorption spectroscopy and spatially resolved electron microscopy and spectroscopy, here we report structural reconstruction (formation of a surface reduced layer, to transition) and chemical evolution (formation of a surface reaction layer) at the surface of LiNi(x)Mn(x)Co(1-2x)O2 particles. These are primarily responsible for the prevailing capacity fading and impedance buildup under high-voltage cycling conditions, as well as the first-cycle coulombic inefficiency. It was found that the surface reconstruction exhibits a strong anisotropic characteristic, which predominantly occurs along lithium diffusion channels. Furthermore, the surface reaction layer is composed of lithium fluoride embedded in a complex organic matrix. This work sets a refined example for the study of surface reconstruction and chemical evolution in battery materials using combined diagnostic tools at complementary length scales.

  11. Facile Synthesis of Boron-Doped rGO as Cathode Material for High Energy Li-O2 Batteries.

    Science.gov (United States)

    Wu, Feng; Xing, Yi; Li, Li; Qian, Ji; Qu, Wenjie; Wen, Jianguo; Miller, Dean; Ye, Yusheng; Chen, Renjie; Amine, Khalil; Lu, Jun

    2016-09-14

    To improve the electrochemical performance of the high energy Li-O2 batteries, it is important to design and construct a suitable and effective oxygen-breathing cathode. Herein, a three-dimensional (3D) porous boron-doped reduction graphite oxide (B-rGO) material with a hierarchical structure has been prepared by a facile freeze-drying method. In this design, boric acid as the boron source helps to form the 3D porous structure, owing to its cross-linking and pore-forming function. This architecture facilitates the rapid oxygen diffusion and electrolyte penetration in the electrode. Meanwhile, the boron-oxygen functional groups linking to the carbon surface or edge serve as additional reaction sites to activate the ORR process. It is vital that boron atoms have been doped into the carbon lattices to greatly activate the electrons in the carbon π system, which is beneficial for fast charge under large current densities. Density functional theory calculation demonstrates that B-rGO exhibits much stronger interactions with Li5O6 clusters, so that B-rGO more effectively activates Li-O bonds to decompose Li2O2 during charge than rGO does. With B-rGO as a catalytic substrate, the Li-O2 battery achieves a high discharge capacity and excellent rate capability. Moreover, catalysts could be added into the B-rGO substrate to further lower the overpotential and enhance the cycling performance in future. PMID:27549204

  12. Structure of electrolyte decomposition products on high voltage spinel cathode materials determined by in situ neutron reflectometry

    Science.gov (United States)

    Browning, Jim; Veith, Gabriel; Baggetto, Loic; Dudney, Nancy; Tenhaeff, Wyatt

    2012-02-01

    Interfacial reactions on electrical energy storage (EES) materials mediate their stability, durability, and cycleablity. Understanding these reactions in situ is difficult since they occur at the liquid-solid interface of an optically absorbing material that hinders the use of techniques such as infra-red spectroscopy. Furthermore, since the interfaces involve liquids classic vacuum-based analytical methods can only probe reaction products, which are stable under vacuum. Here, we present the results of an in situ neutron reflectometry study detailing the formation of a thick solid-electrolyte interphase (SEI) on a high voltage spinel cathode material. The cathode/electrolyte system used in this study is a LiMn1.5Ni0.5O4 thin film subjected to a 1.2 molar LiPF6 in 1:1 ethylene carbonate - dimethyl carbonate electrolyte solution.

  13. Improvement of the Cycling Performance and Thermal Stability of Lithium-Ion Cells by Double-Layer Coating of Cathode Materials with Al₂O₃ Nanoparticles and Conductive Polymer.

    Science.gov (United States)

    Lee, Yoon-Sung; Shin, Won-Kyung; Kannan, Aravindaraj G; Koo, Sang Man; Kim, Dong-Won

    2015-07-01

    We demonstrate the effectiveness of dual-layer coating of cathode active materials for improving the cycling performance and thermal stability of lithium-ion cells. Layered nickel-rich LiNi0.6Co0.2Mn0.2O2 cathode material was synthesized and double-layer coated with alumina nanoparticles and poly(3,4-ethylenedioxythiophene)-co-poly(ethylene glycol). The lithium-ion cells assembled with a graphite negative electrode and a double-layer-coated LiNi0.6Co0.2Mn0.2O2 positive electrode exhibited high discharge capacity, good cycling stability, and improved rate capability. The protective double layer formed on the surface of LiNi0.6Co0.2Mn0.2O2 materials effectively inhibited the dissolution of Ni, Co, and Mn metals from cathode active materials and improved thermal stability by suppressing direct contact between electrolyte solution and delithiated Li(1-x)Ni0.6Co0.2Mn0.2O2 materials. This effective design strategy can be adopted to enhance the cycling performance and thermal stability of other layered nickel-rich cathode materials used in lithium-ion batteries. PMID:26083766

  14. Effect of the capacity design of activated carbon cathode on the electrochemical performance of lithium-ion capacitors

    International Nuclear Information System (INIS)

    Highlights: • MCMB with the optimal pre-lithiation capacity as negative electrode in LIC. • The capacity design of cathode affects the electrochemical performance of LIC. • The optimal designed capacity of positive electrode has been proposed. - ABSTRACT: Lithium-ion capacitors (LICs) are assembled with activated carbon (AC) cathode and pre-lithiated mesocarbon microbeads (MCMB) anode. The effect of AC cathode capacity design on the electrochemical performance of LIC is investigated by the galvanostatic charging-discharging and electrochemical impedance tests. As the designed capacity of AC positive electrode is lower than 50 mAh g−1, the working potential of negative electrode is always in the low and stable plateau, which is conductive to the sufficient utilization and the working potential stability of positive electrode. When the designed capacity of positive electrode is higher than 50 mAh g−1, the instability of negative electrode directly causes the reduced utilization and shortened working potential range of the positive electrode, which is responsible for the capacity attenuation and cycle performance deterioration of LIC. The positive electrode capacity design can realize the optimization of electrochemical performance of LIC. LIC50 exhibits the optimal electrochemical performance, high energy density up to 92.3 Wh kg−1 and power density as high as 5.5 kW kg−1 (based on active material mass of two electrodes), excellent capacity retention of 97.0 % after 1000 cycles. The power density and cycle performance of LIC can be further improved by reducing the AC positive electrode designed capacity

  15. 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.

  16. Structural and morphological studies of manganese-based cathode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Michalska, M., E-mail: monika.michalska83@gmail.com [Institute of Electronic Materials Technology, Wólczyńska 133, 01-919 Warsaw (Poland); Lipińska, L. [Institute of Electronic Materials Technology, Wólczyńska 133, 01-919 Warsaw (Poland); Sikora, A. [Electrotechnical Institute, Division of Electrotechnology and Materials Science, M. Skłodowskiej-Curie 55/61, 50-369 Wrocław (Poland); Ziółkowska, D.; Korona, K.P. [Faculty of Physics, University of Warsaw, Hoża 69, 00-681 Warsaw (Poland); Andrzejczuk, M. [Warsaw University of Technology, Faculty of Material Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland)

    2015-05-25

    Highlights: • Manganese cathode nanomaterials were successfully obtained by modified sol–gel method. • Crystallinity of the powders was confirmed by various structural method. • AFM and Raman spectroscopy showed that LiMnPO{sub 4} is promising material for LIBs. - Abstract: Nanocrystalline powders: lithium-manganese oxide (LiMn{sub 2}O{sub 4}) of spinel and lithium-manganese phosphate (LiMnPO{sub 4}) of olivine structure were synthesized by a modified sol–gel method. In this synthesizing process, lithium and manganese salts and complexing agent were used as reactants. The obtained powders were characterized by a number of methods: X-ray powder diffraction (XRD), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), atomic force microscopy (AFM) and Raman spectroscopy. The mean sizes of crystallites were about 30 nm for LiMn{sub 2}O{sub 4} and 60 nm for LiMnPO{sub 4} nanoparticles. The influence of crystallographic structure on the stability of two manganese compounds was studied. The correlation between the structural and morphological results of spinel LiMn{sub 2}O{sub 4} and olivine LiMnPO{sub 4} properties was examined for the first time in this work.

  17. Electronic structure of lithium borocarbide as a cathode material for a rechargeable Li-ion battery: First-principles calculation

    Science.gov (United States)

    Xu, Qiang; Ban, Chunmei; Dillon, Anne; Wei, Suhuai; Zhao, Yufeng

    2011-03-01

    Traditional cathode materials, such as transition-metal oxides, are heavy, expensive, and often not benign. Therefore, alternative materials without transition metal elements are highly desirable in order to design high-capacity Li-ion batteries of light weight and low price. Here we report on potential application of the LiBC compound as cathode materials, in which graphene-like BC sheets are intercalated by Li ions. The crystal structure and properties of LiBC were firstly reported by Wörle et al. in 1995. Importantly, it was found that the 75% Li ions can be retrieved out of the compound without changing the layered structure. We have performed first-principles calculations based on density functional theory, as implemented in the Vienna Ab-initio Simulation Package. According to our calculation, the layered Li x BC structure can be well preserved at x > 0.5 . Thereversibleelectrochemicalreaction , LiBC Li 0.5 , gives an energy capacity of 609mAh/g and an open-circuit voltage of 2.42V. The volume change is only about 5% during the charging and discharging process. All these results point to a potentially promising application of LiBC as a novel cathode material for high-capacity Li-ion batteries in replacement of the transition metal oxides.

  18. 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)

  19. Optimization of a microbial fuel cell for wastewater treatment using recycled scrap metals as a cost-effective cathode material.

    Science.gov (United States)

    Lefebvre, Olivier; Tan, Zi; Shen, Yujia; Ng, How Y

    2013-01-01

    Microbial fuel cell (MFC) for wastewater treatment is still hindered by the prohibitive cost of cathode material, especially when platinum is used to catalyze oxygen reduction. In this study, recycled scrap metals could be used efficiently as cathode material in a specially-designed MFC. In terms of raw power, the scrap metals ranked as follows: W/Co > Cu/Ni > Inconel 718 > carpenter alloy; however, in terms of cost and long term stability, Inconel 718 was the preferred choice. Treatment performance--assessed on real and synthetic wastewater--was considerably improved either by filling the anode compartment with carbon granules or by operating the MFC in full-loop mode. The latter option allowed reaching 99.7% acetate removal while generating a maximum power of 36 W m(-3) at an acetate concentration of 2535 mg L(-1). Under these conditions, the energy produced by the system averaged 0.1 kWh m(-3) of wastewater treated.

  20. Nanowire Na0.35MnO2 from a hydrothermal method as a cathode material for aqueous asymmetric supercapacitors

    Science.gov (United States)

    Zhang, B. H.; Liu, Y.; Chang, Z.; Yang, Y. Q.; Wen, Z. B.; Wu, Y. P.; Holze, R.

    2014-05-01

    Nanowire Na0.35MnO2 was prepared by a simple and low energy consumption hydrothermal method; its electrochemical performance as a cathode material for aqueous asymmetric supercapacitors in Na2SO4 solution was investigated. Due to the nanowire structure its capacitance (157 F g-1) is much higher than that of the rod-like Na0.95MnO2 (92 F g-1) from solid phase reaction although its sodium content is lower. When it is assembled into an asymmetric aqueous supercapacitor using activated carbon as the counter electrode and aqueous 0.5 mol L-1 Na2SO4 electrolyte solution, the nanowire Na0.35MnO2 shows an energy density of 42.6 Wh kg-1 at a power density of 129.8 W kg-1 based on the total weight of the two electrode material, higher than those for the rod-like Na0.95MnO2, with an energy density of 27.3 Wh kg-1 at a power density of 74.8 W kg-1, and that of LiMn2O4. The new material presents excellent cycling behavior even when dissolved oxygen is not removed from the electrolyte solution. The results hold great promise for practical applications of this cathode material since sodium is much cheaper than lithium and its natural resources are rich.

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

    Institute of Scientific and Technical Information of China (English)

    Jiye Zhan; Xinhui Xia n; Yu Zhong; Xiuli Wang; Jiangping Tu n

    2016-01-01

    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 inter-connected 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.

  2. 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.

  3. A solvent-free microbial-activated air cathode battery paper platform made with pencil-traced graphite electrodes

    Science.gov (United States)

    Lee, Seung Ho; Ban, Ju Yeon; Oh, Chung-Hun; Park, Hun-Kuk; Choi, Samjin

    2016-01-01

    We present the fabrication of an ultra-low cost, disposable, solvent-free air cathode all-paper microbial fuel cell (MFC) that does not utilize any chemical treatments. The anode and cathode were fabricated by depositing graphite particles by drawing them on paper with a pencil (four strokes). Hydrophobic parchment paper was used as a proton exchange membrane (PEM) to allow only H+ to pass. Air cathode MFC technology, where O2 was used as an electron acceptor, was implemented on the paper platform. The bioelectric current was generated by an electrochemical process involving the redox couple of microbial-activated extracellular electron transferred electrons, PEM-passed H+, and O2 in the cathode. A fully micro-integrated pencil-traced MFC showed a fast start-time, producing current within 10 s after injection of bacterial cells. A single miniaturized all-paper air cathode MFC generated a maximum potential of 300 mV and a maximum current of 11 μA during 100 min after a single injection of Shewanella oneidensis. The micro-fabricated solvent-free air cathode all-paper MFC generated a power of 2,270 nW (5.68 mW/m2). The proposed solvent-free air cathode paper-based MFC device could be used for environmentally-friendly energy storage as well as in single-use medical power supplies that use organic matter. PMID:27333815

  4. A solvent-free microbial-activated air cathode battery paper platform made with pencil-traced graphite electrodes

    Science.gov (United States)

    Lee, Seung Ho; Ban, Ju Yeon; Oh, Chung-Hun; Park, Hun-Kuk; Choi, Samjin

    2016-06-01

    We present the fabrication of an ultra-low cost, disposable, solvent-free air cathode all-paper microbial fuel cell (MFC) that does not utilize any chemical treatments. The anode and cathode were fabricated by depositing graphite particles by drawing them on paper with a pencil (four strokes). Hydrophobic parchment paper was used as a proton exchange membrane (PEM) to allow only H+ to pass. Air cathode MFC technology, where O2 was used as an electron acceptor, was implemented on the paper platform. The bioelectric current was generated by an electrochemical process involving the redox couple of microbial-activated extracellular electron transferred electrons, PEM-passed H+, and O2 in the cathode. A fully micro-integrated pencil-traced MFC showed a fast start-time, producing current within 10 s after injection of bacterial cells. A single miniaturized all-paper air cathode MFC generated a maximum potential of 300 mV and a maximum current of 11 μA during 100 min after a single injection of Shewanella oneidensis. The micro-fabricated solvent-free air cathode all-paper MFC generated a power of 2,270 nW (5.68 mW/m2). The proposed solvent-free air cathode paper-based MFC device could be used for environmentally-friendly energy storage as well as in single-use medical power supplies that use organic matter.

  5. Ruthenium-oxide-coated sodium vanadium fluorophosphate nanowires as high-power cathode materials for sodium-ion batteries.

    Science.gov (United States)

    Peng, Manhua; Li, Biao; Yan, Huijun; Zhang, Dongtang; Wang, Xiayan; Xia, Dingguo; Guo, Guangsheng

    2015-05-26

    Sodium-ion batteries are a very promising alternative to lithium-ion batteries because of their reliance on an abundant supply of sodium salts, environmental benignity, and low cost. However, the low rate capability and poor long-term stability still hinder their practical application. A cathode material, formed of RuO2 -coated Na3 V2 O2 (PO4 )2 F nanowires, has a 50 nm diameter with the space group of I4/mmm. When used as a cathode material for Na-ion batteries, a reversible capacity of 120 mAh g(-1) at 1 C and 95 mAh g(-1) at 20 C can be achieved after 1000 charge-discharge cycles. The ultrahigh rate capability and enhanced cycling stability are comparable with high performance lithium cathodes. Combining first principles computational investigation with experimental observations, the excellent performance can be attributed to the uniform and highly conductive RuO2 coating and the preferred growth of the (002) plane in the Na3 V2 O2 (PO4 )2 F nanowires. PMID:25864686

  6. Inverse vulcanization of sulfur with divinylbenzene: Stable and easy processable cathode material for lithium-sulfur batteries

    Science.gov (United States)

    Gomez, Iñaki; Mecerreyes, David; Blazquez, J. Alberto; Leonet, Olatz; Ben Youcef, Hicham; Li, Chunmei; Gómez-Cámer, Juan Luis; Bundarchuk, Oleksandr; Rodriguez-Martinez, Lide

    2016-10-01

    Lithium-Sulfur (Li-S) battery technology is one of the promising candidates for next generation energy storage systems. Many studies have focused on the cathode materials to improve the cell performance. In this work we present a series of poly (S-DVB) copolymers synthesised by inverse vulcanization of sulfur with divinylbenzene (DVB). The poly (S-DVB) cathode shows excellent cycling performances at C/2 and C/4 current rates, respectively. It was demonstrated poly (S-DVB) copolymer containing 20% DVB did not influence the electrochemical performance of the sulfur material, compared to elemental sulfur as high specific capacities over ∼700 mAh g-1 at 500 cycles were achieved at C/4 current rate, comparable to conventional carbon-based S cathodes. However, the use of copolymer network is assumed to act firstly as sulfur reservoir and secondly as mechanical stabilizer, enhancing significantly the cycling lifetime. The Li-poly (S-DVB) cell demonstrated an extremely low degradation rate of 0.04% per cycle achieving over 1600 cycles at C/2 current rate.

  7. One-step synthesis of graphene/polypyrrole nanofiber composites as cathode material for a biocompatible zinc/polymer battery.

    Science.gov (United States)

    Li, Sha; Shu, Kewei; Zhao, Chen; Wang, Caiyun; Guo, Zaiping; Wallace, Gordon; Liu, Hua Kun

    2014-10-01

    The significance of developing implantable, biocompatible, miniature power sources operated in a low current range has become manifest in recent years to meet the demands of the fast-growing market for biomedical microdevices. In this work, we focus on developing high-performance cathode material for biocompatible zinc/polymer batteries utilizing biofluids as electrolyte. Conductive polymers and graphene are generally considered to be biocompatible and suitable for bioengineering applications. To harness the high electrical conductivity of graphene and the redox capability of polypyrrole (PPy), a polypyrrole fiber/graphene composite has been synthesized via a simple one-step route. This composite is highly conductive (141 S cm(-1)) and has a large specific surface area (561 m(2) g(-1)). It performs more effectively as the cathode material than pure polypyrrole fibers. The battery constructed with PPy fiber/reduced graphene oxide cathode and Zn anode delivered an energy density of 264 mWh g(-1) in 0.1 M phosphate-buffer saline.

  8. Chemical stability of La2O3 in La2O3-Mo cathode materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Chemical stability of La2O3 in carbonized and uncarbonized La2O3-Mo cathodes was studied by in-situ XPS analysis. Experimental results show that chemical stability of La2O3 is not good enough. In vacuum and at high temperature, oxygen can be dissociated from the lattice of La2O3 in the uncarbonized La2O3-Mo cathode. Binding energy shifts of La?3d5/2 and La?3d3/2 core peaks, and obvious decrease of satellite peak intensity in La?3d doublet with increasing temperature show that metallic La appears at carbonized La2O3-Mo cathode surface at high temperature.

  9. Solid-state synthesis and electrochemical properties of SmVO4 cathode materials for low temperature SOFCs

    Institute of Scientific and Technical Information of China (English)

    SUN Xueli; LI Song; SUN Juncai

    2006-01-01

    A new cathode material fabricated by solid state reaction method was reported. The SmVO4 powder was obtained by firing the mixture of Sm2O3 and V2O5 powders in the temperature range of 700-1200 ℃. Its structure was identified by X-ray diffraction method and the electrochemical properties of SmVO4 as cathodes for solid oxide fuel cells (SOFCs) were investigated in single unit cell at the temperature ranged from 450-550 ℃. The results of the single fuel cell unit show that the maximum current densities are 641, 797, 688 mA·cm-2 and the maximum power output are 165, 268, 303 mW·cm-2 and the open circuit voltage are 1.04,0.96,0.92Vat 450, 500 and 550 ℃, respectively.

  10. Synthesis and electrochemical characterization of mesoporous Li2FeSiO4/C composite cathode material for Li-ion batteries

    Science.gov (United States)

    Kumar, Ajay; Jayakumar, O. D.; Bazzi, Khadije; Nazri, Gholam-Abbas; Naik, Vaman M.; Naik, Ratna

    2015-03-01

    Lithium iron silicate (Li2FeSiO4) has the potential as cathode for Li ion batteries due to its high theoretical capacity (~ 330 mAh/g) and improved safety. The application of Li2FeSiO4 as cathode material has been challenged by its poor electronic conductivity and slow lithium ion diffusion in the solid phase. In order to solve these problems, we have synthesized mesoporous Li2FeSiO4/C composites by sol-gel method using the tri-block copolymer (P123) as carbon source. The phase purity and morphology of the composite materials were characterized by x-ray diffraction, SEM and TEM. The XRD pattern confirmed the formation of ~ 12 nm size Li2FeSiO4 crystallites in composites annealed at 600 °C for 6 h under argon atmosphere. The electrochemical properties are measured using the composite material as positive electrode in a standard coin cell configuration with lithium as the active anode and the cells were tested using AC impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge cycling. The Li2FeSiO4/C composites showed a discharge capacity of ~ 240 mAh/g at a rate of C/30 at room temperature. The effect of different annealing temperature and synthesis time on the electrochemical performance of Li2FeSiO4/C will be presented.

  11. Innovated application of mechanical activation to separate lead from scrap cathode ray tube funnel glass.

    Science.gov (United States)

    Yuan, Wenyi; Li, Jinhui; Zhang, Qiwu; Saito, Fumio

    2012-04-01

    The disposal of scrap cathode ray tube (CRT) funnel glass has become a global environmental problem due to the rapid shrinkage of new CRT monitor demand, which greatly reduces the reuse for remanufacturing. To detoxificate CRT funnel glass by lead recovery with traditional metallurgical methods, mechanical activation by ball milling was introduced to pretreat the funnel glass. As a result, substantial physicochemical changes have been observed after mechanical activation including chemical breakage and defects formation in glass inner structure. These changes contribute to the easy dissolution of the activated sample in solution. High yield of 92.5% of lead from activated CRT funnel glass by diluted nitric acid leaching and successful formation of lead sulfide by sulfur sulfidization in water have also been achieved. All the results indicate that the application of mechanical activation on recovering lead from CRT funnel glass is efficient and promising, which is also probably appropriate to detoxificate any other kind of leaded glass.

  12. Aspergillus flavus Conidia-derived Carbon/Sulfur Composite as a Cathode Material for High Performance Lithium–Sulfur Battery

    OpenAIRE

    Maowen Xu; Min Jia; Cuiping Mao; Sangui Liu; Shujuan Bao; Jian Jiang; Yang Liu; Zhisong Lu

    2016-01-01

    A novel approach was developed to prepare porous carbon materials with an extremely high surface area of 2459.6 m2g−1 by using Aspergillus flavus conidia as precursors. The porous carbon serves as a superior cathode material to anchor sulfur due to its uniform and tortuous morphology, enabling high capacity and good cycle lifetime in lithium sulfur-batteries. Under a current rate of 0.2 C, the carbon-sulfur composites with 56.7 wt% sulfur loading deliver an initial capacity of 1625 mAh g−1, w...

  13. Mechanism of high luminous efficacy in plasma display panel with high secondary electron emission coefficient cathode material analyzed through three-dimensional fluid model simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Ohyung; Lee, Tae-Ho; Cheong, Hee-Woon; Whang, Ki-Woong [Plasma Laboratory, Inter-University Semiconductor Research Center, Department of Electrical Engineering and Computer Science, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, 151-742 (Korea, Republic of); Bae, Hyun Sook; Jung, Hae-Yoon [Samsung Electronics Co. Ltd., Hwaseong, 445-701 (Korea, Republic of)

    2011-08-15

    The mechanism to realize high luminous efficacy in a plasma display panel fabricated with a cathode material possessing a high secondary electron emission coefficient ({gamma}) for Ne and Xe ions was studied via three-dimensional numerical simulation. When a high {gamma} cathode material is used, the increased electron heating efficacy is responsible for increasing vacuum ultraviolet (VUV) efficacy with 10% Xe content gas. However, the continued availability of sufficient secondary electrons during the dynamic moving phase of the cathode sheath in which the electric field remains weakened causes increasing VUV efficacy with 30% Xe content gas. It was found that the improvement of the luminous efficacy of the plasma display panel with a high {gamma} cathode material is maximized under the condition of high Xe content gas because of the simultaneous increase of the electron heating efficacy and Xe excitation efficacy.

  14. Effect of rare earth ions doping on properties of LiFePO4/C cathode material

    Institute of Scientific and Technical Information of China (English)

    王丽; 焦昌梅; 梁广川; 赵南南; 王亚勉; 李琳慈

    2014-01-01

    LiFe0.99RE0.01PO4/C cathode material was synthesized by solid-state reaction method using FeC2O4·2H2O, Li2CO3, NH4H2PO4, RE(NO3)3·nH2O as raw materials and glucose as a carbon source. The doping effects of rare earth ions, such as La3+, Ce3+, Nd3+, on the structure and electrochemical properties of LiFePO4/C cathode material were systematically investigated. The as-prepared samples were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and particle size analysis. The electrochemical properties were investigated in terms of constant-current charge/discharge cycling tests.The XRD results showed that the rare earth ions doping did not change the olivine structure of LiFePO4, and all the doped samples were of single-phase with high crystallinity. SEM and particle size analysis results showed that the doping of La3+, Ce3+ and Nd3+ led to the decrease of particle size. The electrochemical results exhibited that the doping of La3+ and Ce3+ could improve the high-rate capability of LiFePO4/C cathode material, among which, the material doped with 1% Ce3+ exhibited the optimal elec-trochemical properties, whose specific discharge capacities could reach 128.9, 119.5 and 104.4 mAh/g at 1C, 2C and 5C rates, re-spectively.

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

    DEFF Research Database (Denmark)

    Chen, Leifeng; Aryal, Nabin; Ammam, Fariza;

    2014-01-01

    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.The g...

  16. Material/element-dependent fluorescence-yield modes on soft X-ray absorption spectroscopy of cathode materials for Li-ion batteries

    Directory of Open Access Journals (Sweden)

    Daisuke Asakura

    2016-03-01

    Full Text Available We evaluate the utilities of fluorescence-yield (FY modes in soft X-ray absorption spectroscopy (XAS of several cathode materials for Li-ion batteries. In the case of total-FY (TFY XAS for LiNi0.5Mn1.5O4, the line shape of the Mn L3-edge XAS was largely distorted by the self-absorption and saturation effects, while the distortions were less pronounced at the Ni L3 edge. The distortions were suppressed for the inverse-partial-FY (IPFY spectra. We found that, in the cathode materials, the IPFY XAS is highly effective for the Cr, Mn, and Fe L edges and the TFY and PFY modes are useful enough for the Ni L edge which is far from the O K edge.

  17. Material/element-dependent fluorescence-yield modes on soft X-ray absorption spectroscopy of cathode materials for Li-ion batteries

    Science.gov (United States)

    Asakura, Daisuke; Hosono, Eiji; Nanba, Yusuke; Zhou, Haoshen; Okabayashi, Jun; Ban, Chunmei; Glans, Per-Anders; Guo, Jinghua; Mizokawa, Takashi; Chen, Gang; Achkar, Andrew J.; Hawthron, David G.; Regier, Thomas Z.; Wadati, Hiroki

    2016-03-01

    We evaluate the utilities of fluorescence-yield (FY) modes in soft X-ray absorption spectroscopy (XAS) of several cathode materials for Li-ion batteries. In the case of total-FY (TFY) XAS for LiNi0.5Mn1.5O4, the line shape of the Mn L3-edge XAS was largely distorted by the self-absorption and saturation effects, while the distortions were less pronounced at the Ni L3 edge. The distortions were suppressed for the inverse-partial-FY (IPFY) spectra. We found that, in the cathode materials, the IPFY XAS is highly effective for the Cr, Mn, and Fe L edges and the TFY and PFY modes are useful enough for the Ni L edge which is far from the O K edge.

  18. Microscopic and spectroscopic properties of hydrothermally synthesized nano-crystalline LiFePO4 cathode material

    International Nuclear Information System (INIS)

    Highlights: • Synthesis of nano-crystalline LiFePO4 cathode by hydrothermal synthesis. • Microstructural properties by XRD, FESEM and TEM. • Insights of chemical purity and binding nature through XPS, FTIR and Raman. • Stable electrochemical performance of nano-crystalline LiFePO4 cathode for lithium ion battery application. - Abstract: LiFePO4 is one of the most promising cathode materials as it offers low cost, high abundance, appropriate theoretical capacity and environmental friendly. In the present investigation, nano-crystalline LiFePO4 has been synthesized by hydrothermal method and studied spectroscopic and microscopic properties. The XRD and TEM studies exhibited the formation of orthorhombic structure with Pnma space group. The X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy studies confirm the phase purity of the LiFePO4 powder. The electrochemical characteristics of LiFePO4 are measured in non-aqueous region. It exhibited a good reversible cyclic voltammogram on sweeping the potential upward and downward. The chronopotentiometric measurements performed at various C-rates and the cell exhibited a discharge capacity of 143 mA h/g at 0.1 C with good cycling stability

  19. Micro-nano structure composite cathode material with high sulfur loading for advanced lithium–sulfur batteries

    International Nuclear Information System (INIS)

    ABSTRACT: A micro-nano structure based on polydopamine-grafted hollow carbon nanofiber–sulfur composite (HCNF@PDA–S) is designed as a cathode material for effective trapping of sulfur and polysulfides for lithium–sulfur batteries. Hollow carbon nanofiber@polydopamine (HCNF@PDA) micro-nano structure hybrid is first prepared by an in-situ polymerization dopamine monomer decorating on the surface of HCNFs and then elemental sulfur is infiltrated into the HCNF@PDA hybrid nanostructure by thermal treatment. The obtained HCNF@PDA–S composite shows the micro-nano structure based on the micron-sized hollow carbon nanofiber in length and nano-sized polydopamine grafted on the outer surfaces of the HCNFs with homogeneously distribution of sulfur. Compared with the HCNF–S composite, HCNF@PDA–S composite with a high sulfur content of approximately 80 wt% exhibits better electrochemical performance, which delivers initial discharge capacity of 800 mAh g−1 and maintains 530 mAh g−1 after 200 cycles at 0.5 C rate. The enhancements of electrochemical performances may be attributed to the unique micro-nano hybrid structure based on HCNFs and PDA coating layer, in which the micro-sized HCNFs offer the electronic conductivity and provide a firm porous network of the cathode tolerating the volume expansion of sulfur cathode, and nano-sized PDA layers effectively prevent the dissolution of the polysulfides into the electrolyte

  20. Microscopic and spectroscopic properties of hydrothermally synthesized nano-crystalline LiFePO{sub 4} cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Rosaiah, P.; Hussain, O.M., E-mail: hussainsvu@gmail.com

    2014-11-25

    Highlights: • Synthesis of nano-crystalline LiFePO{sub 4} cathode by hydrothermal synthesis. • Microstructural properties by XRD, FESEM and TEM. • Insights of chemical purity and binding nature through XPS, FTIR and Raman. • Stable electrochemical performance of nano-crystalline LiFePO{sub 4} cathode for lithium ion battery application. - Abstract: LiFePO{sub 4} is one of the most promising cathode materials as it offers low cost, high abundance, appropriate theoretical capacity and environmental friendly. In the present investigation, nano-crystalline LiFePO{sub 4} has been synthesized by hydrothermal method and studied spectroscopic and microscopic properties. The XRD and TEM studies exhibited the formation of orthorhombic structure with Pnma space group. The X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy studies confirm the phase purity of the LiFePO{sub 4} powder. The electrochemical characteristics of LiFePO{sub 4} are measured in non-aqueous region. It exhibited a good reversible cyclic voltammogram on sweeping the potential upward and downward. The chronopotentiometric measurements performed at various C-rates and the cell exhibited a discharge capacity of 143 mA h/g at 0.1 C with good cycling stability.

  1. 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.

  2. Pt–Au/C cathode with enhanced oxygen-reduction activity in PEFCs

    Indian Academy of Sciences (India)

    G Selvarani; S Vinod Selvaganesh; P Sridhar; S Pitchumani; A K Shukla

    2011-04-01

    Carbon-supported Pt–Au (Pt–Au/C) catalyst is prepared separately by impregnation, colloidal and micro-emulsion methods, and characterized by physical and electrochemical methods. Highest catalytic activity towards oxygen-reduction reaction (ORR) is exhibited by Pt–Au/C catalyst prepared by colloidal method. The optimum atomic ratio of Pt to Au in Pt–Au/C catalyst prepared by colloidal method is determined using linear-sweep and cyclic voltammetry in conjunction with cell-polarization studies. Among 3:1, 2:1 and 1:1 Pt–Au/C catalysts, (3:1) Pt–Au/C exhibits maximum electrochemical activity towards ORR. Powder X-ray diffraction pattern and transmission electron micrograph suggest Pt–Au alloy nanoparticles to be well dispersed onto the carbon-support. Energy dispersive X-ray analysis and inductively coupled plasma-optical emission spectroscopy data suggest that the atomic ratios of the alloying elements match well with the expected values. A polymer electrolyte fuel cell (PEFC) operating at 0.6 V with (3:1) Pt–Au/C cathode delivers a maximum power-density of 0.65 W/cm2 in relation to 0.53 W/cm2 delivered by the PEFC with pristine carbon-supported Pt cathode.

  3. Effect of microstructure on low temperature electrochemical properties of LiFePO4/C cathode material

    International Nuclear Information System (INIS)

    Graphical abstract: The low temperature performance of Li-ion batteries and LiFePO4/C composites was discussed. A conclusion that cathode material is the main limitation for the low temperature performance was come up, by comparing the low temperature performance of 18650 Li-ion batteries with LiMn2O4, LiNi1/3Co1/3Mn1/3O2 and LiFePO4/C as cathode materials. The low temperature performance results indicate the LiFePO4/C microstructure is the main factor influencing the low temperature performance of LiFePO4. A new LiFePO4/C with pomegranate-like spherical structure was proposed in this paper, which shows superior low temperature performance, which can be attributed to its uniform fine primary particles and smaller primary particles. - Highlights: • Low temperature performance of Li-ion battery and LiFePO4/C composite was discussed. • Cathode material mainly decided the low temperature performance of Li-ion battery. • LiFePO4/C microstructure mainly affects its low temperature performance. • Pomegranate-like spherical structure LiFePO4/C has good low temperature performance. - Abstract: The low-temperature electrochemical performance of Li-ion batteries is mainly determined by the choice of cathode material, as evident from a comparison of the low-temperature electrochemical performance of the 18650 batteries with the LiMn2O4, LiNi1/3Co1/3Mn1/3O2, and LiFePO4/C as the cathode, respectively, at −20 °C. LiFePO4/C materials with different morphologies and microstructures were prepared by different methods. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatic charge–discharge measurements and EIS. The low-temperature performance of the samples and those of the coin cells utilizing the materials as cathodes were measured. The results indicate that the microstructure of LiFePO4/C is a key factor determining the low-temperature performance of LiFePO4/C. A new type of

  4. 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.

  5. Influence of Parameters of the Glow Discharge on Change of Structure and the Isotope Composition of the Cathode Materials

    Science.gov (United States)

    Savvatimova, I. B.; Gavritenkov, D. V.

    Results of examinations of changes in structure, element, and isotope composition of cathodes after the glow discharge exposure in hydrogen, deuterium, argon, and xenon are submitted. The voltage of the discharge was less than 1000 V and the current was 5-150 mA. Samples before and after ions bombardment in the glow discharge were explored by the methods of mass spectrometry: the secondary ions (SIMS), the secondary ions with additional ionization of neutral sprayed particles (SNMS), spark (SMS), and thermo-ionization (TIMS), and also methods of energy dispersion X-ray spectral analysis (EDX). The alpha-, beta-, gamma- emission, and gamma- spectrometry for radioactive uranium specimens were also carried out before and after experiments in the glow discharge. Changes in structure, isotope, and element composition of the cathode samples depend on current density, integrated ions flow (fluence of ions), kind of irradiating ions and other experimental conditions. Attempts are made to estimate qualitatively and quantitatively the role of each of the parameters on intensity of the observed changes in cathode composition. It is shown that the maximum changes in structure, chemical and isotope composition of the cathode material occur in "hot points," such as craters from microexplosions, phase segregations, blisters and other new formations. Various methods of the analysis revealed that the basic elements Mg, O, Si, Al, and Ca with quantities up to per cents and more were prevailing in these zones and not found out before experiment. The greatest changes of the isotope relations were observed for iron, calcium, silicon, chromium after experiments with pulsing current. EDX method finds out the elements missing in the samples before experiment such as cadmium, strontium, tin. The isotopes with mass number 59 (Co 100%), 55 (Mn 100%), 45 (Sc 100%) are also not found in initial samples and background measurement by TIMS method. Results of changes in the element and isotope

  6. Graphene–Selenium Hybrid Microballs as Cathode Materials for High-performance Lithium–Selenium Secondary Battery Applications

    Science.gov (United States)

    Youn, Hee-Chang; Jeong, Jun Hui; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-01-01

    In this study, graphene–selenium hybrid microballs (G–SeHMs) are prepared in one step by aerosol microdroplet drying using a commercial spray dryer, which represents a simple, scalable continuous process, and the potential of the G–SeHMs thus prepared is investigated for use as cathode material in applications of lithium–selenium secondary batteries. These morphologically unique graphene microballs filled with Se particles exhibited good electrochemical properties, such as high initial specific capacity (642 mA h g−1 at 0.1 C, corresponding to Se electrochemical utilisation as high as 95.1%), good cycling stability (544 mA h g−1 after 100 cycles at 0.1 C; 84.5% retention) and high rate capability (specific capacity of 301 mA h g−1 at 5 C). These electrochemical properties are attributed to the fact that the G–SeHM structure acts as a confinement matrix for suppressing the dissolution of polyselenides in the organic electrolyte, as well as an electron conduction path for increasing the transport rate of electrons for electrochemical reactions. Notably, based on the weight of hybrid materials, electrochemical performance is considerably better than that of previously reported Se-based cathode materials, attributed to the high Se loading content (80 wt%) in hybrid materials. PMID:27480798

  7. Graphene–Selenium Hybrid Microballs as Cathode Materials for High-performance Lithium–Selenium Secondary Battery Applications

    Science.gov (United States)

    Youn, Hee-Chang; Jeong, Jun Hui; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-08-01

    In this study, graphene–selenium hybrid microballs (G–SeHMs) are prepared in one step by aerosol microdroplet drying using a commercial spray dryer, which represents a simple, scalable continuous process, and the potential of the G–SeHMs thus prepared is investigated for use as cathode material in applications of lithium–selenium secondary batteries. These morphologically unique graphene microballs filled with Se particles exhibited good electrochemical properties, such as high initial specific capacity (642 mA h g‑1 at 0.1 C, corresponding to Se electrochemical utilisation as high as 95.1%), good cycling stability (544 mA h g‑1 after 100 cycles at 0.1 C 84.5% retention) and high rate capability (specific capacity of 301 mA h g‑1 at 5 C). These electrochemical properties are attributed to the fact that the G–SeHM structure acts as a confinement matrix for suppressing the dissolution of polyselenides in the organic electrolyte, as well as an electron conduction path for increasing the transport rate of electrons for electrochemical reactions. Notably, based on the weight of hybrid materials, electrochemical performance is considerably better than that of previously reported Se-based cathode materials, attributed to the high Se loading content (80 wt%) in hybrid materials.

  8. Graphene-Selenium Hybrid Microballs as Cathode Materials for High-performance Lithium-Selenium Secondary Battery Applications.

    Science.gov (United States)

    Youn, Hee-Chang; Jeong, Jun Hui; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-01-01

    In this study, graphene-selenium hybrid microballs (G-SeHMs) are prepared in one step by aerosol microdroplet drying using a commercial spray dryer, which represents a simple, scalable continuous process, and the potential of the G-SeHMs thus prepared is investigated for use as cathode material in applications of lithium-selenium secondary batteries. These morphologically unique graphene microballs filled with Se particles exhibited good electrochemical properties, such as high initial specific capacity (642 mA h g(-1) at 0.1 C, corresponding to Se electrochemical utilisation as high as 95.1%), good cycling stability (544 mA h g(-1) after 100 cycles at 0.1 C; 84.5% retention) and high rate capability (specific capacity of 301 mA h g(-1) at 5 C). These electrochemical properties are attributed to the fact that the G-SeHM structure acts as a confinement matrix for suppressing the dissolution of polyselenides in the organic electrolyte, as well as an electron conduction path for increasing the transport rate of electrons for electrochemical reactions. Notably, based on the weight of hybrid materials, electrochemical performance is considerably better than that of previously reported Se-based cathode materials, attributed to the high Se loading content (80 wt%) in hybrid materials. PMID:27480798

  9. Synthesis of nano structured particles for Li-ion cathodic and anodic materials obtained by spray pyrolysis

    International Nuclear Information System (INIS)

    The development of the nano technology has contributed to improve the electrochemical properties in rechargeable batteries. The Spray Pyrolysis method allows to obtain nano structured materials with spherical morphology, narrow particle size distribution and compositional homogeneity. Nano structured particles have been prepared in this work to be used as anodic and cathodic materials in lithium-ion batteries. Among the cathodic materials, the Na-Si-Con (Li3Fe2(PO4)3) structure and the olivine (LiFePO4) phases have been synthesised. The Na-Si-Con iron phosphate favours the accommodation of the ion host, the diffusion and thermal stability. The olivine structure has an open three-dimensional network, favourable for hosting Lithium ions. The characterization by X ray diffraction, electron microscopy (scanning and transmission) and electron diffraction have allowed to identify a mix of crystalline phases of LiFePO4 (Olivine) and Li3Fe2(PO4)3 (Na-Si-Con). Thermal treatments produce porous particles. The tryphilite phase (olivine) appears after a thermal treatment at 800 degree centigrade/12h. Electrochemical results confirm the presence of the Na-Si-Con and olivine phases. Among the materials for being used as anode, the titanium oxides have been classified as good candidates as lithium ion host. The synthesis results in different experimental conditions for obtaining spherical and nano structured titanium oxide particles are presented. (Author)

  10. 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.

  11. The Influences of different cathode materials on Tris-(8-Hydroxyquinoline)- Aluminum Doped with CsNO3 in Organic Light emitting Devices

    Science.gov (United States)

    Chen, Mei-Hsin; Lu, Yin-Jui; Wu, Chung-Chih; Wu, Chih-I.

    2008-03-01

    This paper presents the investigations of interfacial interactions and electron-injection mechanisms between cesium nitrate (CsNO3) and different cathode materials. By using ultraviolet and x-ray photoemission spectroscopy, the properties of electronic structures and the interfacial chemistry are studied. According to our results, there exists a phenomenon of electron exchange at the interface results in changes of Aluminum 2s core level binding energy by 1 eV when aluminum was deposited on CsNO3. This means electrons transfer from cathode materials to the surface of CsNO3, forming a strong dipolar field at the interface and reduction of the electron injection barrier. But, in contract, there exists nearly no reaction between CsNO3 and silver cathode. The evidences show that CsNO3 is more effective only with aluminum cathode due to a reaction between Aluminum, Cesium and Nitrogen atoms.

  12. 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)

  13. LiV3O8/Ag composite nanobelts with enhanced performance as cathode material for rechargeable lithium batteries

    International Nuclear Information System (INIS)

    Graphical abstract: As cathode material for lithium batteries, the LiV3O8/Ag nanobelts exhibit enhanced rate capability and good cyclic stability. A maximum specific discharge capacity of 247, 214, 175, 149, 124, 113 and 103 mA h g−1 can be achieved at the current densities of 50, 100, 300, 500, 1000, 1500 and 2000 mA g−1, respectively. Highlights: • LiV3O8 nanobelts anchored with Ag nanoparticles are prepared by a sol–gel route. • LiV3O8/Ag composite have greatly reduced the charger transfer resistance. • LiV3O8/Ag composite exhibit superior cyclic stability and good rate capability. • High specific capacity of 128 mA h g−1 is remained after 250 cycles at 1000 mA g−1. -- Abstract: Ag nanoparticles anchored LiV3O8 nanobelts have been synthesized via a facile sol–gel route. The as-prepared thin LiV3O8/Ag composite nanobelts have a thickness of several nanometers and a length of dozens of micrometers. The EDX result confirms the existence of Ag element in LVO/Ag composite and the uniform dispersion of Ag nanoparticle among the LVO/Ag composite. When it is evaluated as a cathode material for lithium batteries, the LiV3O8/Ag composite nanobelts exhibit excellent rate capability and long-term cyclic stability. A maximum specific discharge capacity of 247, 214, 175, 149, 124, 113 and 103 mA h g−1 is achieved at the current densities of 50, 100, 300, 500, 1000, 1500 and 2000 mA g−1, respectively. It exhibits no capacity fading after 250 cycles at the current density of 1 A g−1. The superior electrochemical performance indicates their promising application as cathode material in lithium ion batteries

  14. Preliminary study of structural changes in Li2MnSiO4 cathode material during electrochemical reaction

    Science.gov (United States)

    Świętosławski, Michał; Molenda, Marcin; Gajewska, Marta

    2016-06-01

    In this paper, we present exsitu observations of a structure of particular Li2MnSiO4 grains at different states of charge (SOC). The goal of these studies is structural analysis of Li2MnSiO4 cathode material for Li-ion batteries at different stages of electrochemical reaction using transmission electron microscopy. Performed analysis suggests that amorphization process of Li2MnSiO4 is not directly connected with lithium ions deintercalation but with additional electrochemical reactions running in the working cell.

  15. Marine microbial fuel cell : use of stainless steel electrodes as anode and cathode materials

    OpenAIRE

    Dumas, Claire; Mollica, Alfonso; Féron, Damien; Basséguy, Régine; Etcheverry, Luc; Bergel, Alain

    2007-01-01

    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 cath...

  16. Effect of surfactants on the electrochemical behavior of LiFePO4 cathode material for lithium ion batteries

    Science.gov (United States)

    Bazzi, K.; Mandal, B. P.; Nazri, M.; Naik, V. M.; Garg, V. K.; Oliveira, A. C.; Vaishnava, P. P.; Nazri, G. A.; Naik, R.

    2014-11-01

    The application of lithium iron phosphate as positive electrode material for lithium ion batteries has been challenged by its poor electronic conductivity. To improve its conductivity and electrochemical performance, we have synthesized LiFePO4/C composite cathode materials by sol gel technique using long chain fatty acids, such as, lauric, myristic, and oleic acids, as surfactants for carbon coating. The phase purity of the three LiFePO4/C composites was confirmed by X-ray diffraction. The Raman spectroscopy, scanning electron microscopy and transmission electron microscopy measurements show that the surfactants coat the LiFePO4 particles with carbon with varying degree of uniformity depending on the surfactant used. The sample prepared in presence of lauric acid shows smaller particle size and the lowest charge transfer resistance, higher Li-ion diffusion coefficient, higher discharge capacity (∼155 mAh g-1 at C/3 rate), better rate capability and cyclic stability compared to the other two samples. We found the smaller particle size, uniformity of carbon coating, reduced agglomeration, and a lower amount of Fe3+ impurity phase in the samples to be major contributing factors for better electrochemical properties in the LiFePO4/C cathode material.

  17. Cathode material comparison of thermal runaway behavior of Li-ion cells at different state of charges including over charge

    Science.gov (United States)

    Mendoza-Hernandez, Omar Samuel; Ishikawa, Hiroaki; Nishikawa, Yuuki; Maruyama, Yuki; Umeda, Minoru

    2015-04-01

    The analysis of Li-ion secondary cells under outstanding conditions, as overcharge and high temperatures, is important to determine thermal abuse characteristics of electroactive materials and precise risk assessments on Li-ion cells. In this work, the thermal runaway behavior of LiCoO2 and LiMn2O4 cathode materials were compared at different state of charges (SOCs), including overcharge, by carrying out accelerating rate calorimetry (ARC) measurements using 18650 Li-ion cells. Onset temperatures of self-heating reactions and thermal runaway behavior were identified, and by using these onset points thermal mapping plots were made. We were able to identify non-self-heating, self-heating and thermal runaway regions as a function of state of charge and temperature. The cell using LiMn2O4 cathode material was found to be more thermally stable than the cell using LiCoO2. In parallel with the ARC measurements, the electrochemical behavior of the cells was monitored by measuring the OCV and internal resistance of the cells. The electrochemical behavior of the cells showed a slightly dependency on SOC.

  18. In-situ electrochemically active surface area evaluation of an open-cathode polymer electrolyte membrane fuel cell stack

    Science.gov (United States)

    Torija, Sergio; Prieto-Sanchez, Laura; Ashton, Sean J.

    2016-09-01

    The ability to evaluate the electrochemically active surface area (ECSA) of fuel cell electrodes is crucial toward characterising designs and component suites in-situ, particularly when evaluating component durability in endurance testing, since it is a measure of the electrode area available to take part in the fuel cell reactions. Conventional methods to obtain the ECSA using cyclic voltammetry, however, rely on potentiostats that cannot be easily scaled to simultaneously evaluate all cells in a fuel cell stack of practical size, which is desirable in fuel cell development. In-situ diagnostics of an open-cathode fuel cell stack are furthermore challenging because the cells do not each possess an enclosed cathode compartment; instead, the cathodes are rather open to the environment. Here we report on a diagnostic setup that allows the electrochemically active surface area of each cell anode or cathode in an open-cathode fuel cell stack to be evaluated in-situ and simultaneously, with high resolution and reproducibility, using an easily scalable chronopotentiometry methodology and a gas-tight stack enclosure.

  19. Layer cathode methods of manufacturing and materials for Li-ion rechargeable batteries

    Science.gov (United States)

    Kang, Sun-Ho; Amine, Khalil

    2008-01-01

    A positive electrode active material for lithium-ion rechargeable batteries of general formula Li.sub.1+xNi.sub..alpha.Mn.sub..beta.A.sub..gamma.O.sub.2 and further wherein A is Mg, Zn, Al, Co, Ga, B, Zr, or Ti and 0active material is manufactured by employing either a solid state reaction method or an aqueous solution method or a sol-gel method which is followed by a rapid quenching from high temperatures into liquid nitrogen or liquid helium.

  20. A high performance hybrid capacitor with Li2CoPO4F cathode and activated carbon anode

    Science.gov (United States)

    Karthikeyan, K.; Amaresh, S.; Kim, K. J.; Kim, S. H.; Chung, K. Y.; Cho, B. W.; Lee, Y. S.

    2013-06-01

    For the first time, we report the possibility of utilizing Li2CoPO4F as a novel cathode material for hybrid capacitor applications. Li2CoPO4F powders were prepared by a conventional two-step solid state method. A hybrid cell was fabricated using Li2CoPO4F as the cathode along with activated carbon (AC) as the anode in 1 M LiPF6 dissolved in 1 : 1 EC/DMC electrolyte and its electrochemical properties were examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and constant current charge-discharge (C-D) techniques. The Li2CoPO4F/AC cell is capable of delivering a discharge capacitance of 42 F g-1 at 150 mA g-1 current density within 0-3 V region having excellent coulombic efficiency of over 99% even after 1000 cycles. Furthermore, the Li2CoPO4F/AC cell exhibited excellent rate performance with an energy density of ~24 W h kg-1 at 1100 mA g-1 current and maintained about 92% of its initial value even after 30 000 C-D cycles. Electrochemical impedance spectroscopy was conducted to corroborate the results that were obtained and described.For the first time, we report the possibility of utilizing Li2CoPO4F as a novel cathode material for hybrid capacitor applications. Li2CoPO4F powders were prepared by a conventional two-step solid state method. A hybrid cell was fabricated using Li2CoPO4F as the cathode along with activated carbon (AC) as the anode in 1 M LiPF6 dissolved in 1 : 1 EC/DMC electrolyte and its electrochemical properties were examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and constant current charge-discharge (C-D) techniques. The Li2CoPO4F/AC cell is capable of delivering a discharge capacitance of 42 F g-1 at 150 mA g-1 current density within 0-3 V region having excellent coulombic efficiency of over 99% even after 1000 cycles. Furthermore, the Li2CoPO4F/AC cell exhibited excellent rate performance with an energy density of ~24 W h kg-1 at 1100 mA g-1 current and maintained about 92% of its

  1. Gas-solid interfacial modification of oxygen activity in layered oxide cathodes for lithium-ion batteries.

    Science.gov (United States)

    Qiu, Bao; Zhang, Minghao; Wu, Lijun; Wang, Jun; Xia, Yonggao; Qian, Danna; Liu, Haodong; Hy, Sunny; Chen, Yan; An, Ke; Zhu, Yimei; Liu, Zhaoping; Meng, Ying Shirley

    2016-01-01

    Lattice oxygen can play an intriguing role in electrochemical processes, not only maintaining structural stability, but also influencing electron and ion transport properties in high-capacity oxide cathode materials for Li-ion batteries. Here, we report the design of a gas-solid interface reaction to achieve delicate control of oxygen activity through uniformly creating oxygen vacancies without affecting structural integrity of Li-rich layered oxides. Theoretical calculations and experimental characterizations demonstrate that oxygen vacancies provide a favourable ionic diffusion environment in the bulk and significantly suppress gas release from the surface. The target material is achievable in delivering a discharge capacity as high as 301 mAh g(-1) with initial Coulombic efficiency of 93.2%. After 100 cycles, a reversible capacity of 300 mAh g(-1) still remains without any obvious decay in voltage. This study sheds light on the comprehensive design and control of oxygen activity in transition-metal-oxide systems for next-generation Li-ion batteries. PMID:27363944

  2. Gas–solid interfacial modification of oxygen activity in layered oxide cathodes for lithium-ion batteries

    Science.gov (United States)

    Qiu, Bao; Zhang, Minghao; Wu, Lijun; Wang, Jun; Xia, Yonggao; Qian, Danna; Liu, Haodong; Hy, Sunny; Chen, Yan; An, Ke; Zhu, Yimei; Liu, Zhaoping; Meng, Ying Shirley

    2016-01-01

    Lattice oxygen can play an intriguing role in electrochemical processes, not only maintaining structural stability, but also influencing electron and ion transport properties in high-capacity oxide cathode materials for Li-ion batteries. Here, we report the design of a gas–solid interface reaction to achieve delicate control of oxygen activity through uniformly creating oxygen vacancies without affecting structural integrity of Li-rich layered oxides. Theoretical calculations and experimental characterizations demonstrate that oxygen vacancies provide a favourable ionic diffusion environment in the bulk and significantly suppress gas release from the surface. The target material is achievable in delivering a discharge capacity as high as 301 mAh g−1 with initial Coulombic efficiency of 93.2%. After 100 cycles, a reversible capacity of 300 mAh g−1 still remains without any obvious decay in voltage. This study sheds light on the comprehensive design and control of oxygen activity in transition-metal-oxide systems for next-generation Li-ion batteries. PMID:27363944

  3. Preparation of spherical spinel LiCr_(0.04)Mn_(1.96)O_4 cathode materials based on the slurry spray drying method

    Institute of Scientific and Technical Information of China (English)

    JIANG Qinglai; HU Guorong; PENG Zhongdong; DU Ke; CAO Yanbing; TANG Daichun

    2009-01-01

    Regular spherical chromium doped spinel lithium manganese oxides (LiCr_(0.04)Mn_(1.96)O_4) with an average particle size of about 20 μm were prepared by the slurry spray drying process. The materials were compared with non-spherical LiCr_(0.04)Mn_(1.96)O_4 materials prepared by the common drying process, and all materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), laser parti-cle analyzer and Brunauer-Emmett-Teller (BET) specific surface area test. Electrochemical performances of these cathode materials were studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Li/LiCr_(0.04)Mn_(1.96)O_4 battery test. The results show that the spherical active material is single spinel structure, compact, and with narrow particle size distribution and low BET specific surface area. Compared with the non-spherical material, the spherical material prepared by the spray drying process shows a lower electrochemical impedance, a fewer electrochemical polarization and a better charge/discharge rate capability and capacity retention at elevated temperatures.

  4. Enhancement of electrochemical behavior of nanostructured LiFePO4/Carbon cathode material with excess Li

    Science.gov (United States)

    Bazzi, K.; Nazri, M.; Naik, V. M.; Garg, V. K.; Oliveira, A. C.; Vaishnava, P. P.; Nazri, G. A.; Naik, R.

    2016-02-01

    We have synthesized carbon coated LiFePO4 (C-LiFePO4) and C-Li1.05FePO4 with 5 mol% excess Li via sol-gel method using oleic acid as a source of carbon for enhancing electronic conductivity and reducing the average particle size. Although the phase purity of the crystalline samples was confirmed by x-ray diffraction (XRD), the 57Fe Mössbauer spectroscopy analyses show the presence of ferric impurity phases in both stoichiometric and non-stoichiometric C-LiFePO4 samples. Transmission electron microscopy measurements show nanosized C-LiFePO4 particles uniformly covered with carbon, with average particle size reduced from ∼100 nm to ∼50 nm when excess lithium is used. Electrochemical measurements indicate a lower charge transfer resistance and better electrochemical performance for C-Li1.05FePO4 compared to that of C-LiFePO4. The aim of this work is to systematically analyze the nature of impurities formed during synthesis of LiFePO4 cathode material, and their impact on electrochemical performance. The correlation between the morphology, charge transfer resistance, diffusion coefficient and electrochemical performance of C-LiFePO4 and C- Li1.05FePO4 cathode materials are discussed.

  5. Electrochemical properties of large-sized pouch-type lithium ion batteries with bio-inspired organic cathode materials

    Science.gov (United States)

    Yeo, Jae-Seong; Yoo, Eun-Ji; Ha, Sang-Hyeon; Cheong, Dong-Ik; Cho, Sung-Baek

    2016-05-01

    To investigate the feasibility of scaling up bio-inspired organic materials as cathode materials in lithium ion batteries, large-sized pouch cells are successfully prepared via tape casting using lumichrome with an alloxazine structure and aqueous styrene butadiene rubber-carboxymethyl cellulose (SBR-CMC) binders. A battery module with a two-in-series, six-in-parallel (2S6P) configuration is also successfully fabricated and is able to power blue LEDs (850 mW). Lumichrome shows no structural changes during the fabrication processes used to produce the positive electrode. The large-sized pouch cells show two sets of cathodic and anodic peaks with average potentials of 2.58 V and 2.26 V vs. Li/Li+, respectively. The initial discharge capacities are 142 mAh g-1 and 148 mAh g-1 for ethylene carbonate-dimethyl carbonate (EC-DMC) and tetraethylene glycol dimethyl ether (TEGDME) electrolytes, respectively, similar to that of a coin cell (149 mAh g-1). The EC-DMC-injected pouch cells exhibit higher rate performance and cyclability than the TEGDME-injected ones. The TEGDME electrolyte is not suitable for lithium metal anodes because of electrolyte decomposition and subsequent cell swelling.

  6. Iron-rich nanoparticle encapsulated, nitrogen doped porous carbon materials as efficient cathode electrocatalyst for microbial fuel cells

    Science.gov (United States)

    Lu, Guolong; Zhu, Youlong; Lu, Lu; Xu, Kongliang; Wang, Heming; Jin, Yinghua; Jason Ren, Zhiyong; Liu, Zhenning; Zhang, Wei

    2016-05-01

    Developing efficient, readily available, and sustainable electrocatalysts for oxygen reduction reaction (ORR) in neutral medium is of great importance to practical applications of microbial fuel cells (MFCs). Herein, a porous nitrogen-doped carbon material with encapsulated Fe-based nanoparticles (Fe-Nx/C) has been developed and utilized as an efficient ORR catalyst in MFCs. The material was obtained through pyrolysis of a highly porous organic polymer containing iron(II) porphyrins. The characterizations of morphology, crystalline structure and elemental composition reveal that Fe-Nx/C consists of well-dispersed Fe-based nanoparticles coated by N-doped graphitic carbon layer. ORR catalytic performance of Fe-Nx/C has been evaluated through cyclic voltammetry and rotating ring-disk electrode measurements, and its application as a cathode electrocatalyst in an air-cathode single-chamber MFC has been investigated. Fe-Nx/C exhibits comparable or better performance in MFCs than 20% Pt/C, displaying higher cell voltage (601 mV vs. 591 mV), maximum power density (1227 mW m-2 vs. 1031 mW m-2) and Coulombic efficiency (50% vs. 31%). These findings indicate that Fe-Nx/C is more tolerant and durable than Pt/C in a system with bacteria metabolism and thus holds great potential for practical MFC applications.

  7. Synthesis and performance of Li3Ve(PO4)3/C composites as cathode materials

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Carbon-coated Li3V2(PO4)3 cathode materials for lithium-ion batteries were prepared by a carbon-thermal reduction (CTR) method using sucrose as carbon source.The Li3V2(PO4)3/C composite cathode materials were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),and electrochemical measurement.The results show that the Li3V2(PO4)3 samples synthesized using sucrose as carbon source have the same monoclinic structure as the Li3V2(PO4)3 sample synthesized using acetylene black as carbon Source.SEM image exhibits that the particle size is about 1 μm together with homogenous distribution.Electrochemical test shows that the initial discharge capacity of Li3V2(PO4)3 powders is 122 mAh·g-1 at the rate of 0.2C,and the capacity retains 111 mAh·g-1 after 50 cycles.

  8. Single crystalline VO2 nanosheets: A cathode material for sodium-ion batteries with high rate cycling performance

    Science.gov (United States)

    Wang, Wei; Jiang, Bo; Hu, Liwen; Lin, Zheshuai; Hou, Jungang; Jiao, Shuqiang

    2014-03-01

    In recent years, with the growing demands for large-scale applications of rechargeable batteries, the eco-friendly sodium-ion batteries with low price and high charge-discharge rates have attracted much attention. In this work, using a simple hydrothermal process, we successfully synthesize single crystalline VO2 parallel ultrathin nanosheets for the cathode material in sodium-ion batteries. Combined the XRD, XPS, electrochemical measurements with the first-principles simulations, the charge-discharge performance and the mechanism of Na insertion and extraction into/from the VO2 structure have systematically studied. The results reveal that the NaxVO2 products possess semiconductor properties and the interlayer distance almost keeps constant during charge and discharge process, which is beneficial to the transmission of Na ions. The charge and discharge process occurs between Na0.3VO2 and NaVO2. Even at a large current density of 500 mA g-1, the discharge capacity can still keep at 108 mAh g-1. As a cathode material for sodium-ion batteries, the results are outstanding and provide a possibility of large-scale applications for rechargeable sodium-ion batteries.

  9. Nitrogen--sulfur--carbon nanocomposites and their application as cathode materials in lithium--sulfur batteries

    Science.gov (United States)

    Dai, Sheng; Sun, Xiao-Guang; Guo, Bingkun; Wang, Xiqing; Mayes, Richard T.; Ben, Teng; Qiu, Shilun

    2016-09-27

    The invention is directed in a first aspect to electron-conducting porous compositions comprising an organic polymer matrix doped with nitrogen atoms and having elemental sulfur dispersed therein, particularly such compositions having an ordered framework structure. The invention is also directed to composites of such S/N-doped electron-conducting porous aromatic framework (PAF) compositions, or composites of an S/N-doped mesoporous carbon composition, which includes the S/N-doped composition in admixture with a binder, and optionally, conductive carbon. The invention is further directed to cathodes for a lithium-sulfur battery in which such composites are incorporated.

  10. Sulfur-impregnated activated carbon fiber cloth as a binder-free cathode for rechargeable Li-S batteries.

    Science.gov (United States)

    Elazari, Ran; Salitra, Gregory; Garsuch, Arnd; Panchenko, Alexander; Aurbach, Doron

    2011-12-15

    A route for the preparation of binder-free sulfur-carbon cathodes is developed for lithium sulfur batteries. The method is based on the impregnation of elemental sulfur into the micropores of activated carbon fibers. These electrodes demonstrate good electrochemical performance at high current density attributed to the uniform dispersion of sulfur inside the carbon fiber. PMID:22052740

  11. Electrochemical Performance of LiV3O8-xCIxCathode Materials Synthesized by a Low-Temperature Solid State Method

    Institute of Scientific and Technical Information of China (English)

    LIU Li; JIAO Lifang; SUN Junli; LIU Sichen; YUAN Huatang; WANG Yongmei

    2009-01-01

    A series of cathode materials for lithium ion batteries with the formula LiV3O8-xC1x (x=0.00, 0.05, 0.10 and 0.15) were synthesized by a low-temperature solid-state method. The effects of CI substitution on the structure,morphology and electrochemical properties of the cathode materials were investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), charge-discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments. The results show that an enhanced cycle performance is on the C1 doped cathode materials. LiV3O7.90C10.10 shows the best electrochemical performances with the discharge capacity remaining 198.6 mAh/g after 100 cycles, which results from a greater reversibility during cycling and decrease of particle-to-particle impedance.

  12. Solid state cathode materials for secondary magnesium-ion batteries that are compatible with magnesium metal anodes in water-free electrolyte

    Science.gov (United States)

    Crowe, Adam J.; Bartlett, Bart M.

    2016-10-01

    With high elemental abundance, large volumetric capacity, and dendrite-free metal deposition, magnesium metal anodes offer promise in beyond-lithium-ion batteries. However, the increased charge density associated with the divalent magnesium-ion (Mg2+), relative to lithium-ion (Li+) hinders the ion-insertion and extraction processes within many materials and structures known for lithium-ion cathodes. As a result, many recent investigations incorporate known amounts of water within the electrolyte to provide temporary solvation of the Mg2+, improving diffusion kinetics. Unfortunately with the addition of water, compatibility with magnesium metal anodes disappears due to forming an ion-insulating passivating layer. In this short review, recent advances in solid state cathode materials for rechargeable magnesium-ion batteries are highlighted, with a focus on cathode materials that do not require water contaminated electrolyte solutions for ion insertion and extraction processes.

  13. Electrodeposited Pd-Ni-Mo film as a cathode material for hydrogen evolution reaction

    International Nuclear Information System (INIS)

    A Pd-Ni-Mo film was prepared on stainless steel substrate as a novel electrode material for hydrogen evolution reaction catalysis. The surface micro-morphology, chemical composition and microstructure of the Pd-Ni-Mo film were characterizated with SEM, EDS, XPS and TEM. The obtained film is a multiple phase ternary alloy containing crystallines and amorphous phases. The electrochemical measurements showed that the Pd-Ni-Mo film has excellent catalytic activity for hydrogen evolution reaction with good corrosion resistance in 1 M NaOH solution. The proton discharge electrosorption is the rate determining step of hydrogen evolution reaction on Pd-Ni-Mo film surface. The better electrocatalysis performance of the Pd-Ni-Mo film is attributed to its larger real surface as well as the enhanced electrochemical activity of the film surface due to the alloying effect

  14. Electrochemical Kinetics and Performance of Layered Composite Cathode Material Li[Li0.2Ni0.2Mn0.6]O2

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jianming; Shi, Wei; Gu, Meng; Xiao, Jie; Zuo, Pengjian; Wang, Chong M.; Zhang, Jiguang

    2013-10-10

    Lithium-rich, manganese-rich (LMR) layered composite cathode material Li[Li0.2Ni0.2Mn0.6]O2 has been successfully prepared by a co-precipitation method and its structure is confirmed by XRD characterization. The material delivers a high discharge capacity of 281 mAh g-1, when charged and discharged at a low current density of 10 mA g-1. However, significant increase of cell polarization and decrease of discharge capacity are observed at voltages below 3.5 V with increasing current densities. Galvanostatic intermittent titration technique (GITT) analysis demonstrates that lithium ion intercalation/de-intercalation reactions in this material are kinetically controlled by Li2MnO3 and its activated MnO2 component. The relationship between the electrochemical kinetics and rate performance as well as cycling stability has been systematically investigated. High discharge capacity of 149 mAh g-1 can be achieved at 10 C charge rate and C/10 discharge rate. The result demonstrates that the Li2MnO3 based material could withstand high charge rate (except initial activation process), which is very promising for practical applications. A lower discharge current density is preferred to overcome the kinetic barrier of lithium ion intercalation into MnO2 component, in order to achieve higher discharge capacity even at high charge rates.

  15. Mixed Electronic and Ionic Conductor-Coated Cathode Material for High-Voltage Lithium Ion Battery.

    Science.gov (United States)

    Shim, Jae-Hyun; Han, Jung-Min; Lee, Joon-Hyung; Lee, Sanghun

    2016-05-18

    A lithium ionic conductor, Li1.3Al0.3Ti1.7(PO4)3 (LATP), is introduced as a coating material on the surface of Mg-doped LiCoO2 to improve electrochemical performances for high-voltage (4.5 V) lithium ion batteries. Structure, morphology, elemental distribution, and electrical properties of the materials are thoroughly characterized by SEM, TEM, EELS, EDS, and C-AFM. The coating layer is electrically conductive with the aid of Mg ions which are used as a dopant for the active materials; therefore, this mixed electronic ionic conductor strongly enhances the electrochemical performances of initial capacity, cycling property, and rate capability. The LATP coating layer also demonstrates very promising applicability for 4.4 V prismatic full cells with graphite anode, which correspond to the 4.5 V half-cells with lithium anode. The 2900 mA h full cells show 85% of capacity retention after 500 cycles and more than 60% after 700 cycles.

  16. Recent Development of Graphene-Based Cathode Materials for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Man-Ning Lu

    2016-01-01

    Full Text Available Dye-sensitized solar cells (DSSCs have attracted extensive attention for serving as potential low-cost alternatives to silicon-based solar cells. As a vital role of a typical DSSC, the counter electrode (CE is generally employed to collect electrons via the external circuit and speed up the reduction reaction of I3- to I- in the redox electrolyte. The noble Pt is usually deposited on a conductive glass substrate as CE material due to its excellent electrical conductivity, electrocatalytic activity, and electrochemical stability. To achieve cost-efficient DSSCs, reasonable efforts have been made to explore Pt-free alternatives. Recently, the graphene-based CEs have been intensively investigated to replace the high-cost noble Pt CE. In this paper, we provided an overview of studies on the electrochemical and photovoltaic characteristics of graphene-based CEs, including graphene, graphene/Pt, graphene/carbon materials, graphene/conducting polymers, and graphene/inorganic compounds. We also summarize the design and advantages of each graphene-based material and provide the possible directions for designing new graphene-based catalysts in future research for high-performance and low-cost DSSCs.

  17. A preliminary investigation into the new class of lithium intercalating LiNiSiO4 cathode material

    Science.gov (United States)

    Jayaprakash, N.; Kalaiselvi, N.; Periasamy, P.

    2008-01-01

    A unique attempt to exploit silicate chemistry for a possible enhancement of the electrochemical properties of a lithium ion system via exploration of the novel category lithium intercalating LiNiSiO4 cathode has been made through the present study. A novel citric acid assisted modified sol-gel method (CAM sol-gel) has been adopted to synthesize the title compound with a formation temperature positioned well below 500 °C, as derived from thermal studies. A powder x-ray diffraction (PXRD) pattern evidenced the absence of undesirable peaks and confirmed the formation of a hexagonal lattice structure with enhanced crystallinity and phase purity, and the presence of uniformly distributed particles of ~200 nm size with well defined grain boundaries is obvious from the scanning electron microscopy (SEM) image of LiNiSiO4 material. Further, magic angle spinning (MAS) 7Li nuclear magnetic resonance (NMR) results from LiNiSiO4 confirmed the presence of a layered type of crystal arrangement. A cyclic voltammetry (CV) study performed on a LiNiSiO4 cathode revealed an excellent reversibility without any change in the peak position upon extended cycling, thus substantiating the structural stability upon progressive cycling.

  18. Electrochemical characterization of MnO2 as the cathode material for a high voltage hybrid capacitor

    Institute of Scientific and Technical Information of China (English)

    Jian-ling Li; Fei Gao; Yan Jing; Rui-ying Miao; Ke-zhong Wu; Xin-dong Wang

    2009-01-01

    Manganese dioxide (MnO_2) was prepared using the ultrasonic method. Its electrochemical performance was evaluated as the cathode material for a high voltage hybrid capacitor. And the specific capacitance of the MnO_2 electrode reached 240 F-g-1. The new hybrid capacitor was constructed, combining Al/Al_2O_3 as the anode and MnO_2 as the cathode with electrolyte for the aluminum electrolytic capacitor to solve the problem of low working voltage of a supercapacitor unit. The results showed that the hybrid ca-pacitor had a high energy density and the ability of quick charging and discharging according to the electrochemical performance test. The capacitance was 84.4 μF, and the volume and mass energy densities were greatly improved compared to those of the traditional aluminum electrolytic capacitor of 47 μF. The analysis of electrochemical impedance spectroscopy (EIS) showed that the hybrid ca-pacitor had good impedance characteristics.

  19. Synthesis and Electrochemical Studies of LiNi0.2Co0.8VO4 Cathode Material by Sol-Gel Method

    Science.gov (United States)

    Prakash, D.; Sanjeeviraja, C.

    2013-07-01

    Lithium nickel cobalt vanadate (LiNi0.2Co0.8VO4) cathode material was prepared by using sol-gel method. Rietveld refinement analysis of powder x-ray diffraction (PXRD) pattern confirmed the prepared compound having cubic structure and showed no evidence of secondary phase peaks. The field emission scanning microscopy (FESEM) image of the compound showed that the particles have submicron size. The x-ray photoelectron spectroscopy (XPS) results showed that the oxidation states of cobalt and vanadium was +3 and +5, respectively. The electrochemical performance of the cathode material was also performed.

  20. Development of thin film cathodes for lithium-ion batteries in the material system Li–Mn–O by r.f. magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, J., E-mail: julian.fischer@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Applied Materials Physics (IAM-AWP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Adelhelm, C.; Bergfeldt, T. [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Applied Materials Physics (IAM-AWP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Chang, K. [RWTH Aachen University, Materials Chemistry, Kopernikusstrasse 10, 46 52074 Aachen (Germany); Ziebert, C.; Leiste, H.; Stüber, M.; Ulrich, S. [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Applied Materials Physics (IAM-AWP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Music, D.; Hallstedt, B. [RWTH Aachen University, Materials Chemistry, Kopernikusstrasse 10, 46 52074 Aachen (Germany); Seifert, H.J. [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Applied Materials Physics (IAM-AWP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2013-01-01

    Today most commercially available lithium ion batteries are still based on the toxic and expensive LiCoO{sub 2} as a standard cathode material. However, lithium manganese based cathode materials are cheaper and environmentally friendlier. In this work cubic-LiMn{sub 2}O{sub 4} spinel, monoclinic-Li{sub 2}MnO{sub 3} and orthorhombic-LiMnO{sub 2} thin films have been synthesized by non-reactive r.f. magnetron sputtering from two ceramic targets (LiMn{sub 2}O{sub 4}, LiMnO{sub 2}) in a pure argon discharge. The deposition parameters, namely target power and working gas pressure, were optimized in a combination with a post deposition heat treatment with respect to microstructure and electrochemical behavior. The chemical composition was determined using inductively coupled plasma optical emission spectroscopy and carrier gas hot extraction. The films' crystal structure, phase evolution and morphology were investigated by X-ray diffraction, micro Raman spectroscopy and scanning electron microscopy. Due to the fact that these thin films consist of the pure active material without any impurities, such as binders or conductive additives like carbon black, they are particularly well suited for measurements of the intrinsic physical properties, which is essential for fundamental understanding. The electrochemical behavior of the cubic and the orthorhombic films was investigated by galvanostatic cycling in half cells against metallic lithium. The cubic spinel films exhibit a maximum specific capacity of ∼ 82 mAh/g, while a specific capacity of nearly 150 mAh/g can be reached for the orthorhombic counterparts. These films are promising candidates for future all solid state battery applications. - Highlights: ► Synthesis of 3 Li–Mn–O structures by one up-scalable thin film deposition method ► Formation of o-LiMnO{sub 2} by r.f. magnetron sputtering in combination with post-annealing ► Discharge capacity with o-LiMnO{sub 2} cathodes twice as high as for c

  1. New lithium iron pyrophosphate as 3.5 V class cathode material for lithium ion battery.

    Science.gov (United States)

    Nishimura, Shin-ichi; Nakamura, Megumi; Natsui, Ryuichi; Yamada, Atsuo

    2010-10-01

    A new pyrophosphate compound Li(2)FeP(2)O(7) was synthesized by a conventional solid-state reaction, and its crystal structure was determined. Its reversible electrode operation at ca. 3.5 V vs Li was identified with the capacity of a one-electron theoretical value of 110 mAh g(-1) even for ca. 1 μm particles without any special efforts such as nanosizing or carbon coating. Li(2)FeP(2)O(7) and its derivatives should provide a new platform for related lithium battery electrode research and could be potential competitors to commercial olivine LiFePO(4), which has been recognized as the most promising positive cathode for a lithium-ion battery system for large-scale applications, such as plug-in hybrid electric vehicles.

  2. A fundamental study of chromium deposition on solid oxide fuel cell cathode materials

    Science.gov (United States)

    Tucker, Michael C.; Kurokawa, Hideto; Jacobson, Craig P.; De Jonghe, Lutgard C.; Visco, Steven J.

    Chromium contamination of metal oxides and SOFC cathode catalysts is studied in the range 700-1000 °C. Samples are exposed to a moist air atmosphere saturated with volatile Cr species in the presence and absence of direct contact between the sample and ferritic stainless steel powder. Chromium contamination of the samples is observed to occur via two separate pathways: surface diffusion from the stainless steel surface and vapor deposition from the atmosphere. Surface diffusion dominates in all cases. Surface diffusion is found to be a significant source of Cr contamination for LSM and LSCF at 700, 800, and 1000 °C. Vapor deposition of Cr onto LSCF was observed at each of these temperatures, but was not observed for LSM at 700 or 800 °C. Comparison of the behavior for LSM, LSCF, and single metal oxides suggests that Mn and Co, respectively, are responsible for the Cr contamination of these catalysts.

  3. Development of highly active and stable hybrid cathode catalyst for PEMFCs

    Science.gov (United States)

    Jung, Won Suk

    Polymer electrolyte membrane fuel cells (PEMFCs) are attractive power sources of the future for a variety of applications including portable electronics, stationary power, and automobile application. However, sluggish cathode kinetics, high Pt cost, and durability issues inhibit the commercialization of PEMFCs. To overcome these drawbacks, research has been focused on alloying Pt with transition metals since alloy catalysts show significantly improved catalytic properties like high activity, selectivity, and durability. However, Pt-alloy catalysts synthesized using the conventional impregnation method exhibit uneven particle size and poor particle distribution resulting in poor performance and/or durability in PEMFCs. In this dissertation, a novel catalyst synthesis methodology is developed and compared with catalysts prepared using impregnation method and commercial catalysts. Two approaches are investigated for the catalyst development. The catalyst durability was studied under U. S. DRIVE Fuel Cell Tech Team suggested protocols. In the first approach, the carbon composite catalyst (CCC) having active sites for oxygen reduction reaction (ORR) is employed as a support for the synthesis of Pt/CCC catalyst. The structural and electrochemical properties of Pt/CCC catalyst are investigated using high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, while RDE and fuel cell testing are carried out to study the electrochemical properties. The synergistic effect of CCC and Pt is confirmed by the observed high activity towards ORR for the Pt/CCC catalyst. The second approach is the synthesis of Co-doped hybrid cathode catalysts (Co-doped Pt/CCC) by diffusing the Co metal present within the CCC support into the Pt nanoparticles during heat-treatment. The optimized Co-doped Pt/CCC catalyst performed better than the commercial catalysts and the catalyst prepared using the impregnation method in PEMFCs and showed high

  4. Cathodes - Technological review

    Energy Technology Data Exchange (ETDEWEB)

    Cherkouk, Charaf; Nestler, Tina [Institut für Experimentelle Physik, Technische Universität Bergakademie Freiberg, Leipziger Straße 23, 09596 Freiberg (Germany)

    2014-06-16

    Lithium cobalt oxide (LiCoO{sub 2}) was already used in the first commercialized Li-ion battery by SONY in 1990. Still, it is the most frequently used cathode material nowadays. However, LiCoO{sub 2} is intrinsically unstable in the charged state, especially at elevated temperatures and in the overcharged state causing volume changes and transport limitation for high power batteries. In this paper, some technological aspects with large impact on cell performance from the cathode material point of view will be reviewed. At first it will be focused on the degradation processes and life-time mechanisms of the cathode material LiCoO{sub 2}. Electrochemical and structural results on commercial Li-ion batteries recorded during the cycling will be discussed. Thereafter, advanced nanomaterials for new cathode materials will be presented.

  5. Cathodes - Technological review

    International Nuclear Information System (INIS)

    Lithium cobalt oxide (LiCoO2) was already used in the first commercialized Li-ion battery by SONY in 1990. Still, it is the most frequently used cathode material nowadays. However, LiCoO2 is intrinsically unstable in the charged state, especially at elevated temperatures and in the overcharged state causing volume changes and transport limitation for high power batteries. In this paper, some technological aspects with large impact on cell performance from the cathode material point of view will be reviewed. At first it will be focused on the degradation processes and life-time mechanisms of the cathode material LiCoO2. Electrochemical and structural results on commercial Li-ion batteries recorded during the cycling will be discussed. Thereafter, advanced nanomaterials for new cathode materials will be presented

  6. Electrochemical Cathodic Polarization, a Simplified Method That Can Modified and Increase the Biological Activity of Titanium Surfaces: A Systematic Review.

    Directory of Open Access Journals (Sweden)

    Jose Carlos Bernedo Alcazar

    Full Text Available The cathodic polarization seems to be an electrochemical method capable of modifying and coat biomolecules on titanium surfaces, improving the surface activity and promoting better biological responses.The aim of the systematic review is to assess the scientific literature to evaluate the cellular response produced by treatment of titanium surfaces by applying the cathodic polarization technique.The literature search was performed in several databases including PubMed, Web of Science, Scopus, Science Direct, Scielo and EBSCO Host, until June 2016, with no limits used. Eligibility criteria were used and quality assessment was performed following slightly modified ARRIVE and SYRCLE guidelines for cellular studies and animal research.Thirteen studies accomplished the inclusion criteria and were considered in the review. The quality of reporting studies in animal models was low and for the in vitro studies it was high. The in vitro and in vivo results reported that the use of cathodic polarization promoted hydride surfaces, effective deposition, and adhesion of the coated biomolecules. In the experimental groups that used the electrochemical method, cellular viability, proliferation, adhesion, differentiation, or bone growth were better or comparable with the control groups.The use of the cathodic polarization method to modify titanium surfaces seems to be an interesting method that could produce active layers and consequently enhance cellular response, in vitro and in vivo animal model studies.

  7. Electrochemical Cathodic Polarization, a Simplified Method That Can Modified and Increase the Biological Activity of Titanium Surfaces: A Systematic Review

    Science.gov (United States)

    2016-01-01

    Background The cathodic polarization seems to be an electrochemical method capable of modifying and coat biomolecules on titanium surfaces, improving the surface activity and promoting better biological responses. Objective The aim of the systematic review is to assess the scientific literature to evaluate the cellular response produced by treatment of titanium surfaces by applying the cathodic polarization technique. Data, Sources, and Selection The literature search was performed in several databases including PubMed, Web of Science, Scopus, Science Direct, Scielo and EBSCO Host, until June 2016, with no limits used. Eligibility criteria were used and quality assessment was performed following slightly modified ARRIVE and SYRCLE guidelines for cellular studies and animal research. Results Thirteen studies accomplished the inclusion criteria and were considered in the review. The quality of reporting studies in animal models was low and for the in vitro studies it was high. The in vitro and in vivo results reported that the use of cathodic polarization promoted hydride surfaces, effective deposition, and adhesion of the coated biomolecules. In the experimental groups that used the electrochemical method, cellular viability, proliferation, adhesion, differentiation, or bone growth were better or comparable with the control groups. Conclusions The use of the cathodic polarization method to modify titanium surfaces seems to be an interesting method that could produce active layers and consequently enhance cellular response, in vitro and in vivo animal model studies. PMID:27441840

  8. Synthesis and shaping of new cathode materials for ITSOFC fuel cell: fabrication and test cells; Synthese et mise en forme de nouveaux materiaux de cathode pour piles ITSOFC: realisation et tests de cellules

    Energy Technology Data Exchange (ETDEWEB)

    Lalanne, C.

    2005-10-15

    The development of the Solid Oxide Fuel Cells is dependent on the reduction of the cathodic over-potential measured at 600-700 Celsius degrees. In this way, in the last few years, we have made a selection from new cathode materials in the Institute; the oxygen over-stoichiometric oxides formulated A{sub 2}MO{sub 4+{delta}} (K{sub 2}NiF{sub 4}-type structure), show enhanced electrocatalytic and oxygen conduction properties. A detailed study has been performed on the compositions Nd{sub 2-x}NiO{sub 4+{delta}} (x = 0 and 0.05): the oxygen reduction is characterised by impedance spectroscopy and voltametry measurements (symmetrical configuration cell under air). Electrochemical analysis carried out under different oxygen partial pressures and various cathodic over-potentials have led us to identify the various contributions of the mechanism of the dioxygen reduction. Using powders with controlled morphology (coming from different synthesis ways) has resulted in a reduction of the electrode polarisation phenomena, which is the limiting step of the process still remaining in the interface cathode / electrolyte ionic transfer. In addition, due to these promising results (low area specific resistances and minimized cathodic over-potentials), the first tests in a complete fuel cell device have been performed. After an optimisation of the shaping parameters, i.e. selection of the suitable coating process and of the sintering thermal cycle, promising current densities of 1,3 A/cm{sup 2}, for 0,7 V have been measured at 800 Celsius degrees, the operating temperature. (author)

  9. Study on the stability of Li2MnSiO4 cathode material in different electrolyte systems for Li-ion batteries

    International Nuclear Information System (INIS)

    This study reports on the thorough investigation into the interaction between nanosized carbon-coated Li2MnSiO4 and various electrolytes, which has revealed significant changes of the active material after soaking in the electrolyte. Apart from the standard electrolyte salt lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and the F-free salt lithium bis-oxalatoborate (LiBOB) were used for soaking tests and compared in terms of corrosion power with Li2MnSiO4. Carbon-coated Li2MnSiO4 samples were obtained by solid-state synthesis and stored in contact with the electrolyte. The aged samples were fully characterized by means of several analytical techniques (XRD, XPS, SEM, ATR-FTIR). The results show that Li2MnSiO4 decomposes in LiPF6-based electrolyte at high temperatures, due to the formation of HF, which causes corrosion of the material and dissolution of Mn. No degradation was observed after soaking in the LiBOB-based electrolyte. The corrosion of the active material in standard electrolyte system, together with irreversible structural changes upon Li electrochemical extraction, are considered as the main reasons for the poor capacity retention upon cycling of the Li2MnSiO4-based cathode

  10. Understanding Voltage Decay in Lithium-Rich Manganese-Based Layered Cathode Materials by Limiting Cutoff Voltage.

    Science.gov (United States)

    Yang, Jingsong; Xiao, Lifen; He, Wei; Fan, Jiangwei; Chen, Zhongxue; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2016-07-27

    The effect of the cutoff voltages on the working voltage decay and cyclability of the lithium-rich manganese-based layered cathode (LRMO) was investigated by electrochemical measurements, electrochemical impedance spectroscopy, ex situ X-ray diffraction, transmission electron microscopy, and energy dispersive spectroscopy line scan technologies. It was found that both lower (2.0 V) and upper (4.8 V) cutoff voltages cause severe voltage decay with cycling due to formation of the spinel phase and migration of the transition metals inside the particles. Appropriate cutoff voltage between 2.8 and 4.4 V can effectively inhibit structural variation as the electrode demonstrates 92% capacity retention and indiscernible working voltage decay over 430 cycles. The results also show that phase transformation not only on high charge voltage but also on low discharge voltage should be addressed to obtain highly stable LRMO materials. PMID:27383918

  11. 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 [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zheng, Jianming [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lv, Dongping [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wei, Yi [Peking Univ., Beijing (China); Zheng, Jiaxin [Peking Univ., Beijing (China); Wang, Zhiguo [Univ. of Electronic Science and Technology of China, Chengdu (China); Kuppan, Saravanan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yu, Jianguo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Luo, Langli [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Edwards, Danny J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Olszta, Matthew J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Amine, Khalil [Argonne National Lab. (ANL), Argonne, IL (United States); Liu, Jun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xiao, Jie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pan, Feng [Peking Univ., Beijing (China); Chen, Guoying [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhang, Jiguang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Chong M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    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.

  12. Template-Engaged Synthesis of 1D Hierarchical Chainlike LiCoO2 Cathode Materials with Enhanced High-Voltage Lithium Storage Capabilities.

    Science.gov (United States)

    Wu, Naiteng; Zhang, Yun; Wei, Yunhong; Liu, Heng; Wu, Hao

    2016-09-28

    A novel 1D hierarchical chainlike LiCoO2 organized by flake-shaped primary particles is synthesized via a facile template-engaged strategy by using CoC2O4·2H2O as a self-sacrificial template obtained from a simple coprecipitation method. The resultant LiCoO2 has a well-built hierarchical structure, consisting of secondary micrometer-sized chains and sub-micrometer-sized primary flakes, while these primary LiCoO2 flakes have specifically exposed fast-Li(+)-diffused active {010} facets. Owing to this unique hierarchical structure, the chainlike LiCoO2 serves as a stable cathode material for lithium-ion batteries (LIBs) operated at a high cutoff voltage up to 4.5 V, enabling highly reversible capacity, remarkable rate performance, and long-term cycle life. Specifically, the chainlike LiCoO2 can deliver a reversible discharge capacity as high as 168, 156, 150, and 120 mAh g(-1) under the current density of 0.1, 0.5, 1, and 5 C, respectively, while about 85% retention of the initial capacity can be retained after 200 cycles under 1 C at room temperature. Moreover, the chainlike LiCoO2 also shows an excellent cycling stability at a wide operating temperature range, showing the capacity retention of ∼73% after 200 cycles at 55 °C and of ∼68% after 50 cycles at -10 °C, respectively. The work described here suggests the great potential of the hierarchical chainlike LiCoO2 as high-voltage cathode materials aimed toward developing advanced LIBs with high energy density and power density.

  13. Effect of microstructure on low temperature electrochemical properties of LiFePO{sub 4}/C cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Nannan; Zhi, Xiaoke; Wang, Li; Liu, Yanhui; Liang, Guangchuan, E-mail: liangguangchuan@hebut.edu.cn

    2015-10-05

    Graphical abstract: The low temperature performance of Li-ion batteries and LiFePO{sub 4}/C composites was discussed. A conclusion that cathode material is the main limitation for the low temperature performance was come up, by comparing the low temperature performance of 18650 Li-ion batteries with LiMn{sub 2}O{sub 4}, LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} and LiFePO{sub 4}/C as cathode materials. The low temperature performance results indicate the LiFePO{sub 4}/C microstructure is the main factor influencing the low temperature performance of LiFePO{sub 4}. A new LiFePO{sub 4}/C with pomegranate-like spherical structure was proposed in this paper, which shows superior low temperature performance, which can be attributed to its uniform fine primary particles and smaller primary particles. - Highlights: • Low temperature performance of Li-ion battery and LiFePO{sub 4}/C composite was discussed. • Cathode material mainly decided the low temperature performance of Li-ion battery. • LiFePO{sub 4}/C microstructure mainly affects its low temperature performance. • Pomegranate-like spherical structure LiFePO{sub 4}/C has good low temperature performance. - Abstract: The low-temperature electrochemical performance of Li-ion batteries is mainly determined by the choice of cathode material, as evident from a comparison of the low-temperature electrochemical performance of the 18650 batteries with the LiMn{sub 2}O{sub 4}, LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2}, and LiFePO{sub 4}/C as the cathode, respectively, at −20 °C. LiFePO{sub 4}/C materials with different morphologies and microstructures were prepared by different methods. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatic charge–discharge measurements and EIS. The low-temperature performance of the samples and those of the coin cells utilizing the materials as cathodes were measured. The results

  14. Preliminary studies of biominerals-coated spinel LiMn2 O4 as a cathode material on electrochemical performances for Li-ion rechargeable batteries

    Science.gov (United States)

    Vediappan, Kumaran; Lee, Chang Woo

    2010-05-01

    Lithium manganese oxide (LiMn2O4) is an inexpensive and pollution-free cathode material for Li-ion rechargeable batteries. In this study, spinel LiMn2O4 cathode material was coated with biomineral powders by the mechano-chemical method. In the course of the material synthesis, citric acid and acryl amide were added to serve as a complexing agent and a gelling agent, respectively, followed by a calcination process at 700 °C for 6 h in a high-purity argon atmosphere. The spinel LiMn2O4 and biominerals-coated spinel LiMn2O4 cathode materials were, from diverse viewpoints, characterized by x-ray diffraction, field emission-scanning electron microscopy, Fourier transform infrared spectroscopy and the electrochemical cycling method to understand the mechanism of improvements in electrochemical performances. We suggest that the biominerals-coated spinel LiMn2O4 is a good candidate as a low cost and environmentally friendly cathode material showing the enlarged capacity characteristic of Li-ion rechargeable batteries.

  15. Study of Poly (3,4-ethylenedioxythiophene)/MnO2 as Composite Cathode Materials for Aluminum-Air Battery

    International Nuclear Information System (INIS)

    Highlights: • Open-tunnel structure of MnO2 catalysts were prepared by the hydrothermal method. • PEDOT was deposited on MnO2/carbon paper by oxidative chemical vapor deposition. • PEDOT/α-MnO2/10AA 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 (MnO2) with poly-(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer. The catalyst powders of α-MnO2 and β-MnO2 are prepared by hydrothermal method with different precursors, while PEDOT conducting polymer is subsequently deposited on the screen-printed electrodes (MnO2/carbon paper) by oxidative chemical vapor deposition (oCVD). Material characteristics of prepared MnO2 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 MnO2. From experimental observations and a density functional theory (DFT) study, the conductivity of PEDOT/α-MnO2 is found to be higher than PEDOT/β-MnO2 contributed to structural effect mediated improvements in charge transfer. As a result, integrating the deposition of PEDOT on α-MnO2/carbon paper as composite cathode is suitable for the use in aluminum-air battery

  16. First principle study of LiXS2 (X = Ga, In) as cathode materials for Li ion batteries

    Science.gov (United States)

    Feng-Ya, Rao; Fang-Hua, Ning; Li-Wei, Jiang; Xiang-Ming, Zeng; Mu-Sheng, Wu; Bo, Xu; Chu-Ying, Ouyang

    2016-02-01

    From first principle calculations, we demonstrate that LiXS2 (X = Ga, In) compounds have potential applications as cathode materials for Li ion batteries. It is shown that Li can be extracted from the LiXS2 lattice with relatively small volume change and the XS4 tetrahedron structure framework remains stable upon delithiation. The theoretical capacity and average intercalation potential of the LiGaS2 (LiInS2) cathode are 190.4 (144.2) mAh/g and 3.50 V (3.53 V). The electronic structures of the LiXS2 are insulating with band gaps of 2.88 eV and 1.99 eV for X = Ga and In, respectively. However, Li vacancies, which are formed through delithiation, change the electronic structure substantially from insulating to metallic structure, indicating that the electrical conductivities of the LiXS2 compounds should be good during cycling. Li ion migration energy barriers are also calculated, and the results show that Li ion diffusions in the LiXS2 compounds can be as good as those in the currently widely used electrode materials. Project supported by the National High Technology and Development Key Program, China (Grant No. 2015AA034201), the National Natural Science Foundation of China (Grant Nos. 11234013 and 11264014), the Natural Science Foundation of Jiangxi Province, China (Grant Nos. 20133ACB21010, 20142BAB212002, and 20132BAB212005), and the Foundation of Jiangxi Provincial Education Committee, China (Grant Nos. GJJ14254 and KJLD14024).

  17. Deposition and characterization of thin films of materials with application in cathodes for lithium rechargeable micro batteries

    International Nuclear Information System (INIS)

    In this thesis work is reported the deposition and characterization of thin films of materials of the type LiMO2, 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 Al2O3; for that the study of the formation of thin films in bilayer form LiMO2/AI2O3 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 LiCoO2 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 LiNiO2, it was necessary to synthesize the oxide starting from a reaction of solid state among nickel oxide (NiO) and lithium oxide (Li2O) obtaining stoichiometric LiNiO2. For the formation of the thin films of LiNiO2 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 (LiCoO2 and LiNiO2). (Author)

  18. Accelerated OH(-) transport in activated carbon air cathode by modification of quaternary ammonium for microbial fuel cells.

    Science.gov (United States)

    Wang, Xin; Feng, Cuijuan; Ding, Ning; Zhang, Qingrui; Li, Nan; Li, Xiaojing; Zhang, Yueyong; Zhou, Qixing

    2014-04-01

    Activated carbon (AC) is a promising catalyst for the air cathode of microbial fuel cells (MFCs) because of its high performance and low cost. To increase the performance of AC air cathodes, the acceleration of OH(-) transport is one of the most important methods, but it has not been widely investigated. Here we added quaternary ammonium to ACs by in situ anchoring of a quaternary ammonium/epoxide-reacting compound (QAE) or ex situ mixing with anion exchange resins in order to modify ACs from not only the external surface but also inside the pores. In 50 mM phosphate buffer solution (PBS), the in situ anchoring of QAE was a more effective way to increase the power. The highest power density of 2781 ± 36 mW/m(2), which is 10% higher than that of the control, was obtained using QAE-anchored AC cathodes. When the medium was switched to an unbuffered NaCl solution, the increase in maximum power density (885 ± 25 mW/m(2)) was in accordance with the anion exchange capacity (0.219 mmol/g). The highest power density of the anion exchange resin-mixed air cathode was 51% higher than that of the control, indicating that anion exchange is urgently needed in real wastewaters. Excess anchoring of QAE blocked both the mesopores and micropores, causing the power output to be inhibited. PMID:24597673

  19. Material properties in complement activation

    DEFF Research Database (Denmark)

    Moghimi, S. Moein; Andersen, Alina Joukainen; Ahmadvand, Davoud;

    2011-01-01

    -immune performance’ relationship studies in nanomedicine research at many fronts. The interaction between nanomaterials and the complement system is complex and regulated by inter-related factors that include nanoscale size, morphology and surface characteristics. Each of these parameters may affect complement...... activation differently and through different sensing molecules and initiation pathways. The importance of material properties in triggering complement is considered and mechanistic aspects discussed. Mechanistic understanding of complement events could provide rational approaches for improved material design...

  20. Fe-Si networks in Na2FeSiO4 cathode materials.

    Science.gov (United States)

    Wu, P; Wu, S Q; Lv, X; Zhao, X; Ye, Z; Lin, Z; Wang, C Z; Ho, K M

    2016-08-24

    Using a combination of adaptive genetic algorithm search, motif-network search scheme and first-principles calculations, we have systematically studied the low-energy crystal structures of Na2FeSiO4. We show that the low-energy crystal structures with different space group symmetries can be classified into several families based on the topologies of their Fe-Si networks. In addition to the diamond-like network which is shared by most of the low-energy structures, another three robust Fe-Si networks are also found to be stable during the charge/discharge process. The electrochemical properties of representative structures from these four different Fe-Si networks in Na2FeSiO4 and Li2FeSiO4 are investigated and found to be strongly correlated with the Fe-Si network topologies. Our studies provide a new route to characterize the crystal structures of Na2FeSiO4 and Li2FeSiO4 and offer useful guidance for the design of promising cathodes for Na/Li ion batteries. PMID:27523264

  1. Ionic liquid-assisted solvothermal synthesis of hollow Mn2O3 anode and LiMn2O4 cathode materials for Li-ion batteries

    Science.gov (United States)

    He, Xin; Wang, Jun; Jia, Haiping; Kloepsch, Richard; Liu, Haidong; Beltrop, Kolja; Li, Jie

    2015-10-01

    Mn-based Mn2O3 anode and LiMn2O4 cathode materials are prepared by a solvothermal method combined with post annealing process. Environmentally friendly ionic liquid 1-Butyl-3-methylimidazolium tetrafluoroborate as both structure-directing agent and fluorine source is used to prepare hollow polyhedron MnF2 precursor. Both target materials Mn2O3 anode and LiMn2O4 cathode have the morphology of the MnF2 precursor. The Mn2O3 anode using carboxymethyl cellulose as binder could deliver slight better electrochemical performance than the one using poly (vinyldifluoride) as binder. The former has an initial charge capacity of 800 mAh g-1 at a current density of 101.8 mA g-1, and exhibits no obvious capacity decay for 150 cycles at 101.8 mA g-1. The LiMn2O4 cathode material prepared with molten salt assistant could display much better electrochemical performance than the one prepared without molten salt assistance. In particular, it has an initial discharge capacity of 117.5 mAh g-1 at a current density of 0.5C and good rate capability. In the field of lithium ion batteries, both the Mn2O3 anode and LiMn2O4 cathode materials could exhibit enhanced electrochemical performance due to the well formed morphology based on the ionic liquid-assisted solvothermal method.

  2. Designing and Thermal Analysis of Safe Lithium Ion Cathode Materials for High Energy Applications

    Science.gov (United States)

    Hu, Enyuan

    Safety is one of the most critical issues facing lithium-ion battery application in vehicles. Addressing this issue requires the integration of several aspects, especially the material chemistry and the battery thermal management. First, thermal stability investigation was carried out on an attractive high energy density material LiNi0.5Mn1.5O4. New findings on the thermal-stability and thermal-decomposition-pathways related to the oxygen-release are discovered for the high-voltage spinel Li xNi0.5Mn1.5O4 (LNMO) with ordered (o-) and disordered (d-) structures at fully delithiated (charged) state using a combination of in situ time-resolved x-ray diffraction (TR-XRD) coupled with mass spectroscopy (MS) and x-ray absorption spectroscopy (XAS). Both fully charged o--LixNi0.5Mn1.5O 4 and d-LixNi0.5Mn1.5O 4 start oxygen-releasing structural changes at temperatures below 300 °C, which is in sharp contrast to the good thermal stability of the 4V-spinel LixMn2O4 with no oxygen being released up to 375 °C. This is mainly caused by the presence of Ni4+ in LNMO, which undergoes dramatic reduction during the thermal decomposition. In addition, charged o-LNMO shows better thermal stability than the d-LNMO counterpart, due to the Ni/Mn ordering and smaller amount of the rock-salt impurity phase in o-LNMO. Newly identified two thermal-decomposition-pathways from the initial LixNi0.5Mn1.5O 4 spinel to the final NiMn2O4-type spinel structure with and without the intermediate phases (NiMnO3 and alpha-Mn 2O3) are found to play key roles in thermal stability and oxygen release of LNMO during thermal decomposition. In addressing the safety issue associated with LNMO, Fe is selected to partially substitute Ni and Mn simultaneously utilizing the electrochemical activity and structure-stabilizing high spin Fe3+. The synthesized LiNi1/3Mn4/3Fe1/3O4 showed superior thermal stability and satisfactory electrochemical performance. At charged state, it is able to withstand the temperature as

  3. Preparation and Characterisation of LiFePO4/CNT Material for Li-Ion Batteries

    OpenAIRE

    Rushanah Mohamed; Shan Ji; Vladimir Linkov

    2011-01-01

    Li-ion battery cathode materials were synthesised via a mechanical activation and thermal treatment process and systematically studied. LiFePO4/CNT composite cathode materials were successfully prepared from LiFePO4 material. The synthesis technique involved growth of carbon nanotubes onto the LiFePO4 using a novel spray pyrolysis-modified CVD technique. The technique yielded LiFePO4/CNT composite cathode material displaying good electrochemical activity. The composite cathode exhibited excel...

  4. Lithium-Excess Research of Cathode Material Li2MnTiO4 for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Xinyi Zhang

    2015-11-01

    Full Text Available 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 reveal that the charge-discharge performance of the material improves remarkably with the lithium content increasing. Particularly, the first discharging capacity at the current of 30 mA g−1 increases from 112.2 mAh g−1 of Li2.0MnTiO4 to 187.5 mAh g−1 of Li2.4Mn0.8TiO4. In addition, the ex situ XRD experiments indicate that the monoclinic Li2MnTiO4 tends to transform to an amorphous state with the extraction of lithium ions, while the cubic Li2MnTiO4 phase shows better structural reversibility and stability.

  5. Synthesis, characterization and electrochemical studies of LiNi0.8M0.2O2 cathode material for rechargeable lithium batteries

    Indian Academy of Sciences (India)

    R Sathiyamoorthi; P Manisankar; P Shakkthivel; Mu Sang Lee; T Vasudevan

    2008-06-01

    LiNiO2 and substituted nickel oxides, LiNi0.8M0.2O2 and LiCo0.8M0.2O2 (M = Mg2+, Ca2+, Ba2+), have been synthesized using simple solid state technique and used as cathode active materials for lithium rechargeable cells. Physical properties of the synthesized products are discussed in the structural (XRD, TEM, SEM with EDAX) and spectroscopic (FTIR) measurements. XRD results show that the compounds are similar to LiNiO2 in structure. TEM and SEM analyses were used to examine the particle size, nature and morphological aspects of the synthesized oxides. The composition of the materials was explored by EDAX analysis. Electrochemical studies were carried out in the range 3–4.5 V (vs Li metal) using 1 M LiBF4 in ethylene carbonate/dimethyl carbonate as the electrolyte. The doping involving 20% Mg resulted in a discharge capacity of 185 mAhg-1 at 0.1 mA/cm2 and remained stable even after 25 cycles. Discharge capacity retention for Mg doped lithium nickelate at 25th cycle was noted to be nearly 7% higher than for the undoped material.

  6. Preparation and electrical properties of Ca-doped La(2)NiO(4+δ) cathode materials for IT-SOFC.

    Science.gov (United States)

    Shen, Yongna; Zhao, Hailei; Liu, Xiaotong; Xu, Nansheng

    2010-12-01

    Ca-doped La(2)NiO(4+δ) is synthesized via the nitrate-citrate route. The effects of Ca substitution for La on the sinterability, lattice structure and electrical properties of La(2)NiO(4+δ) are investigated. Ca-doping is unfavorable for the densification process of La(2-x)Ca(x)NiO(4+δ) materials. The introduction of Ca leads to the elongation of the La-O(2) bond length, which provides more space for the migration of oxygen ion in La(2)O(2) rock salt layers. The substitution of Ca increases remarkably the electronic conductivity of La(2-x)Ca(x)NiO(4+δ). With increasing Ca-doping level, both the excess oxygen concentration and the activation energy of oxygen ion migration decrease, resulting in an optimization where a highest ionic conductivity is presented. Ca-doping is charge compensated by the oxidation of Ni(2+) to Ni(3+) and the desorption of excess oxygen. The substitution of Ca enhances the structural stability of La(2)NiO(4+δ) material at high temperatures and renders the material a good thermal cycleability. La(1.7)Ca(0.3)NiO(4+δ) exhibits an excellent chemical compatibility with CGO electrolyte. La(2-x)Ca(x)NiO(4+δ) is a promising cathode alternative for solid oxide fuel cells. PMID:20967398

  7. Porous nitrogen-doped carbon derived from silk fibroin protein encapsulating sulfur as a superior cathode material for high-performance lithium-sulfur batteries

    Science.gov (United States)

    Zhang, Jiawei; Cai, Yurong; Zhong, Qiwei; Lai, Dongzhi; Yao, Juming

    2015-10-01

    The features of a carbon substrate are crucial for the electrochemical performance of lithium-sulfur (Li-S) batteries. Nitrogen doping of carbon materials is assumed to play an important role in sulfur immobilisation. In this study, natural silk fibroin protein is used as a precursor of nitrogen-rich carbon to fabricate a novel, porous, nitrogen-doped carbon material through facile carbonisation and activation. Porous carbon, with a reversible capacity of 815 mA h g-1 at 0.2 C after 60 cycles, serves as the cathode material in Li-S batteries. Porous carbon retains a reversible capacity of 567 mA h g-1, which corresponds to a capacity retention of 98% at 1 C after 200 cycles. The promising electrochemical performance of porous carbon is attributed to its mesoporous structure, high specific surface area and nitrogen doping into the carbon skeleton. This study provides a general strategy to synthesise nitrogen-doped carbons with a high specific surface area, which is crucial to improve the energy density and electrochemical performance of Li-S batteries.

  8. 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.

  9. A novel surface-sensitive X-ray absorption spectroscopic detector to study the thermal decomposition of cathode materials for Li-ion batteries

    Science.gov (United States)

    Nonaka, Takamasa; Okuda, Chikaaki; Oka, Hideaki; Nishimura, Yusaku F.; Makimura, Yoshinari; Kondo, Yasuhito; Dohmae, Kazuhiko; Takeuchi, Yoji

    2016-09-01

    A surface-sensitive conversion-electron-yield X-ray absorption fine structure (CEY-XAFS) detector that operates at elevated temperatures is developed to investigate the thermal decomposition of cathode materials for Li-ion batteries. The detector enables measurements with the sample temperature controlled from room temperature up to 450 °C. The detector is applied to the LiNi0.75Co0.15Al0.05Mg0.05O2 cathode material at 0% state of charge (SOC) and 50% SOC to examine the chemical changes that occur during heating in the absence of an electrolyte. The combination of surface-sensitive CEY-XAFS and bulk-sensitive transmission-mode XAFS shows that the reduction of Ni and Co ions begins at the surface of the cathode particles at around 150 °C, and propagates inside the particle upon further heating. These changes with heating are irreversible and are more obvious at 50% SOC than at 0% SOC. The fraction of reduced Ni ions is larger than that of reduced Co ions. These results demonstrate the capability of the developed detector to obtain important information for the safe employment of this cathode material in Li-ion batteries.

  10. Na0.282V2O5: A high-performance cathode material for rechargeable lithium batteries and sodium batteries

    Science.gov (United States)

    Cai, Yangsheng; Zhou, Jiang; Fang, Guozhao; Cai, Gemei; Pan, Anqiang; Liang, Shuquan

    2016-10-01

    Na0.282V2O5 nanorods have been successfully prepared using a facile hydrothermal reaction followed by a calcination treatment, which is then used as a cathode for lithium batteries and sodium batteries for the first time. The crystal structure is refined to be a monoclinic lattice, which contains 3D tunnels along the b-axis. The Na ions are located inside the tunnels and form "pillar effect" to prevent the collapse of the crystal structure. As cathode material for lithium batteries, the Na0.282V2O5 nanorods deliver a high discharge specific capacity of 264, 186, 191 and 149 mA h g-1 at the current density of 50, 500, 1000 and 1500 mA g-1, respectively. The Na0.282V2O5 nanorods demonstrate the excellent cycling performance up to 400 cycles at 1 and 1.5 A g-1. Importantly, as cathode material for sodium batteries, Na0.282V2O5 exhibits superior long-term cyclic stability up to 1000 cycles at 0.3 A g-1. The results of ex-situ XRD, EIS and first-principle calculation indicate that the Na0.282V2O5 possesses good electrical conductivity and structural stability. Our work demonstrates that the Na0.282V2O5 material could be considered as a potential cathode for lithium-ion batteries, and even sodium ion batteries.

  11. SrCo{sub 1-x}Sb{sub x}O{sub 3-{delta}} perovskite oxides as cathode materials in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Aguadero, A.; Perez-Coll, D.; Escudero, M.J. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); de la Calle, C.; Alonso, J.A. [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain); Daza, L. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain)

    2009-07-01

    The SrCo{sub 1-x}Sb{sub x}O{sub 3-{delta}} (x = 0.05, 0.1, 0.15 and 0.2) system was tested as possible cathode for solid oxide fuel cells (SOFCs). X-ray diffraction results show the stabilization of a tetragonal P4/mmm structure with Sb contents between x = 0.05 and x = 0.15. At x = 0.2 a phase transition takes place and the material is defined in the cubic Pm-3m space group. In comparison with the undoped hexagonal SrCoO{sub 3} phase, the obtained compounds present high thermal stability without abrupt changes in the expansion coefficient. In addition, a great enhancement of the electrical conductivity was observed at low and intermediate temperatures (T {<=} 800 C). The sample with x = 0.05 displays the highest conductivity value that reaches 500 S cm{sup -1} at 400 C and is over 160 S cm{sup -1} in the usual working conditions of a cathode in SOFC (650-900 C). Moreover, the impedance spectra of the SrCo{sub 1-x}Sb{sub x}O{sub 3-{delta}}/Ce{sub 0.8}Nd{sub 0.2}O{sub 2-{delta}}/SrCo{sub 1-x}Sb{sub x}O{sub 3-(delta)} (x {>=} 0.05) symmetrical cells reveal polarization resistances below 0.09 {omega} cm{sup 2} at 750 C which are much smaller than that displayed by the pristine SrCoO{sub 3-{delta}} sample. The composition with x = 0.05 shows the lowest ASR values ranging from 0.009 to 0.23 {omega} cm{sup 2} in the 900-600 C temperature interval with an activation energy of 0.82 eV. (author)

  12. Improving the rate capability of high voltage lithium-ion battery cathode material LiNi0.5Mn1.5O4 by ruthenium doping

    Science.gov (United States)

    Kiziltas-Yavuz, Nilüfer; Bhaskar, Aiswarya; Dixon, Ditty; Yavuz, Murat; Nikolowski, Kristian; Lu, Li; Eichel, Rüdiger-A.; Ehrenberg, Helmut

    2014-12-01

    The citric acid-assisted sol-gel method was used to produce the high-voltage cathodes LiNi0.5Mn1.5O4 and LiNi0.4Ru0.05Mn1.5O4 at 800 °C and 1000 °C final calcination temperatures. High resolution powder diffraction using synchrotron radiation, inductively coupled plasma - optical emission spectroscopy and scanning electron microscopy analyses were carried out to characterize the structure, chemical composition and morphology. X-ray absorption spectroscopy studies were conducted to confirm Ru doping inside the spinel as well as to compare the oxidation states of transition metals. The formation of an impurity LixNi1-xO in LiNi0.5Mn1.5O4 powders annealed at high temperatures (T ≥ 800 °C) can be suppressed by partial substitution of Ni2+ by Ru4+ ion. The LiNi0.4Ru0.05Mn1.5O4 powder synthesized at 1000 °C shows the highest performance regarding the rate capability and cycling stability. It has an initial capacity of ∼139 mAh g-1 and capacity retention of 84% after 300 cycles at C/2 charging-discharging rate between 3.5 and 5.0 V. The achievable discharge capacity at 20 C for a charging rate of C/2 is ∼136 mAh g-1 (∼98% of the capacity delivered at C/2). Since the electrode preparation plays a crucial role on parameters like the rate capability, the influence of the mass loading of active materials in the cathode mixture is discussed.

  13. Hollow Cathode With Multiple Radial Orifices

    Science.gov (United States)

    Brophy, John R.

    1992-01-01

    Improved hollow cathode serving as source of electrons has multiple radial orifices instead of single axial orifice. Distributes ion current more smoothly, over larger area. Prototype of high-current cathodes for ion engines in spacecraft. On Earth, cathodes used in large-diameter ion sources for industrial processing of materials. Radial orientation of orifices in new design causes current to be dispersed radially in vicinity of cathode. Advantageous where desireable to produce plasma more nearly uniform over wider region around cathode.

  14. Scale-up of Metal Hexacyanoferrate Cathode Material for Sodium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dzwiniel, Trevor L. [Argonne National Lab. (ANL), Argonne, IL (United States); Pupek, Krzysztof Z. [Argonne National Lab. (ANL), Argonne, IL (United States); Krumdick, Gregory K. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-10-04

    Sharp Laboratories of America (SLA) approached Argonne National Laboratory with a bench-scale process to produce material for a sodium-ion battery, referred to as Prussian Blue, and a request to produce 1 kg of material for their ARPA-E program. The target performance criteria was an average capacity of >150 mAh/g.

  15. Ca3Co4O9+δ, a growing potential SOFC cathode material: impact of the layer composition and thickness on the electrochemical properties

    NARCIS (Netherlands)

    Rolle, A.; Abbas, H.A.A.; Huo, D.; Capoen, E.; Mentré, O.; Vannier, R.N.; Daviero-Minaud, S.; Boukamp, B.A.

    2016-01-01

    The thermoelectric material Ca3Co4O9 + δ (CCO), with an electronic conductivity of σe = 240 S·cm− 1 at 650 °C and a good chemical and mechanical compatibility with the standard Ce0.9Gd0.1O1.95 electrolyte (CGO, TEC: 9–10 · 10− 6 K− 1), was recently identified as a potential cathode material for soli

  16. Robust Low-Cost Cathode for Commercial Applications

    Science.gov (United States)

    Patterson, Michael J.

    2007-01-01

    Under funding from the NASA Commercial Technology Office, a cathode assembly was designed, developed, fabricated, and tested for use in plasma sources for ground-based materials processing applications. The cathode development activity relied on the large prior NASA investment and successful development of high-current, high-efficiency, long-life hollow cathodes for use on the International Space Station Plasma Contactor System. The hollow cathode was designed and fabricated based on known engineering criteria and manufacturing processes for compatibility with the requirements of the plasma source. The transfer of NASA GRC-developed hollow cathode technology for use as an electron emitter in the commercial plasma source is anticipated to yield a significant increase in process control, while eliminating the present issues of electron emitter lifetime and contamination.

  17. Influence of Doping Rare Earth on Performance of Lithium Manganese Oxide Spinels as Cathode Materials for Lithium-Ion Batteries

    Institute of Scientific and Technical Information of China (English)

    Tang Zhiyuan; Zhang Na; Lu Xinghe; Huang Qinghua

    2005-01-01

    Some rare earth doping spinel LiMn2-xRExO4 (RE=La, Ce, Nd) cathode materials for lithium ion batteries were synthesized by the solid-state reaction method. The structure characteristics of these produced samples were investigated by XRD, SEM, and particle size distribution analysis. According to the microstructure and charge-discharge testing, the effect of doping rare earth on stabilizing the spinel structure was analyzed. Through a series of doping experiments, it is shown that when the doping content x within the range of 0.01~0.02 the cycle performance of the materials is greatly improved. The discharge capacity of the sample LiMn1.98La0.02O4, LiMn1.98Ce0.02O4 and LiMn1.98Nd0.02O4 remain 119.1, 114.2 and 117.5 mAh*g-1 after 50 cycles.

  18. Hierarchical LiNixCoyO2 mesostructures as high-performance cathode materials for lithium ion batteries

    Science.gov (United States)

    Shang, Longmei; Li, He; Lai, Hongwei; Li, Danqin; Wu, Qiang; Yang, Lijun; Wang, Xizhang; Hu, Zheng

    2016-09-01

    Lithium ion batteries (LIBs) with enhanced performance to commercial ones are urgently demanded in portable electric devices. Herein, we demonstrate an efficient strategy to improve the electrochemical performance of a dominant commercial cathode material (LiCoO2) by constructing 3D hierarchical LiNixCoyO2 (h-LNCO). The h-LNCO presents porous spherical-shaped morphology at mesoscale while comprises interconnected primary nanoparticles at nanoscale. Such a unique morphology endows the h-LNCO with porous structure for easy penetration of electrolyte, relatively small size of primary particles with short Li+ ions diffusion length and abundant exposed surface in favor of Li+ intercalation/deintercalation. The synergism of these merits makes the h-LNCO exhibit superior electrochemical properties with high capacity, superior cyclability and rate capability, much better than the solid granular LNCO counterparts and commercial LiCoO2. This strategy of constructing porous hierarchical mesostructures could be extended to other electrode materials for electrochemical energy storage.

  19. Enhanced electrochemical performance in LiFePO4/graphene nanocomposite cathode material for lithium ion batteries

    Science.gov (United States)

    Dhindsa, Kulwinder; Mandal, B.; Lin, M. W.; Nazri, M.; Vaishnava, P.; Naik, V.; Nazri, G. A.; Naik, R.; Zhou, Z. X.

    2012-02-01

    We synthesized LiFePO4/graphene nano-composite employing a sol-gel method, where graphene oxide solution was added to the LiFePO4 precursors during the synthesis. Electrical measurement reveals that the addition of 10% graphene (by weight) to LiFePO4 increases its conductivity by 5 orders of magnitude. SEM images of the composite show that the material consists of LiFePO4 nanoparticles (with a mean particle size ˜ 50 nm) homogeneously mixed with graphene sheets; the latter provides a three-dimensional conducting network for Li+ ion and electron transport. A large specific capacity of 170 mAh/g was observed at a discharge rate of C/2. To further increase the conductivity and inhibit particle size growth of LiFePO4 (thus to increase the rate capacity), we coated the nanoparticles with a thin carbon layer by adding 0.25M lauric acid as precursor in addition to graphene oxide during the synthesis. The respective roles of graphene and lauric-acid-induced carbon coating in the specific capacity and charge-discharge rate of the LiFePO4 cathode material will be discussed.

  20. Preparation of LiNixCol-xO2 Cathode Material for Li-ion Cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The cathode materials LiNixCo1-xO2(0≤x≤1) for lithium ion battery were prepared in solid phase. The effects of synthesis temperature, the time of heat treatment and also the ratio of raw materials on products were discussed. The results showed that the products preheated under 600℃ and then sintered under constant temperature 750℃ were better than those sintered under constant temperature 650℃ or 850℃,and their layer structures were more obvious and their initial capacity was higher. The longer the heat-treating time is,the stronger the products' XRD peaks intensity and the better their structures and electrochemical performance are. The samples LiNixCo1-xO2(0≤x≤1) with a perfect structure and electrochemical performance were synthesized. And the products initial capacity was perfect when n(Li)∶n(Ni)∶n(Co)=1.15∶0.3∶0.7,viz. 156.146mAh/g.

  1. Multifunctional semi-interpenetrating polymer network-nanoencapsulated cathode materials for high-performance lithium-ion batteries

    Science.gov (United States)

    Kim, Ju-Myung; Park, Jang-Hoon; Lee, Chang Kee; Lee, Sang-Young

    2014-04-01

    As a promising power source to boost up advent of next-generation ubiquitous era, high-energy density lithium-ion batteries with reliable electrochemical properties are urgently requested. Development of the advanced lithium ion-batteries, however, is staggering with thorny problems of performance deterioration and safety failures. This formidable challenge is highly concerned with electrochemical/thermal instability at electrode material-liquid electrolyte interface, in addition to structural/chemical deficiency of major cell components. Herein, as a new concept of surface engineering to address the abovementioned interfacial issue, multifunctional conformal nanoencapsulating layer based on semi-interpenetrating polymer network (semi-IPN) is presented. This unusual semi-IPN nanoencapsulating layer is composed of thermally-cured polyimide (PI) and polyvinyl pyrrolidone (PVP) bearing Lewis basic site. Owing to the combined effects of morphological uniqueness and chemical functionality (scavenging hydrofluoric acid that poses as a critical threat to trigger unwanted side reactions), the PI/PVP semi-IPN nanoencapsulated-cathode materials enable significant improvement in electrochemical performance and thermal stability of lithium-ion batteries.

  2. Synthesis of LiCoxNi1-xO2 cathode materials from electrolysis Co-Ni alloys

    Institute of Scientific and Technical Information of China (English)

    YE Mao; WEI Jin-ping; CAO Xiao-yan; ZHAI Jin-ling; WANG Xiao-yu; SUN Xin; YAN Jie

    2005-01-01

    The LiCoxNi1-xO2 (x-0.2, 0.5 and 0.8) cathode materials were synthesized by sintering the mixtures of lithium salt and Cox Ni1-x (OH)2 (x= 0.2, 0.5 and 0.8) which were achieved from corresponding Cox Ni1-x alloys by electrolysis technique. The structure and electrochemical characteristics of the obtained LiCoxNi1-xO2 were studied by XRD, SEM, PSCA and charge-discharge cycling test. The results show that the electrochemical capacities of the LiCoxNi1-xO2 (x=0.2, 0.5 and 0.8) materials are improved with the increase of the Ni content. The electrochemical performance of LiCo0.2 Ni0.8 O2 made in oxygen atmosphere has higher charge-discharge capacity and better cycleability compared with the one made in air atmosphere.

  3. Properties and Structure of Spinel Li-Mn-O-F Compounds for Cathode Materials of Secondary Lithium-ion Battery

    Institute of Scientific and Technical Information of China (English)

    CHEN, Zhao-Yong; GAO, Li-Zhen; LIU, Xin-Quan; YU, Zuo-Long

    2001-01-01

    The spinel Li-Mn-O-F compound cathode materials were syn-thesized by solid-state reaction from calculated amounts LiOH·H2O, MnO2(EMD) and LiF. The results of the elec-trochemical test demonstrated that these materials exhibited excellent electrochemical properties. It's initial capacity is ~ 115 mAh·g-1 and reversible efficiency is about 100%. After 60 cycles, its capacity is still around 110 mAh·g1 with nearly 100% reversible efficiency. The spinel Li-Mn-O-F compound possibly has two structure models: interstitial model [Li]-[Mn3+x Mn4+2-x-]O4Fδ, in which the fluorine is located on the interstice of crystal lattice, and substituted model [Li ]-[Mn3+x+Mn4+2-x]O4-δFδ, which the fluorine atom substituted the oxygen atom. The electrochemical result supports the interstitial model [Li] [Mn3+x+Mn4+2-x]O4Fδ.

  4. Solution-processed cathode interfacial layer materials for high-efficiency polymer solar cells

    OpenAIRE

    Biao Xiao; Hongbin Wu; Yong Cao

    2015-01-01

    Polymer solar cells (PSCs) are a new type of renewable energy source currently being extensively investigated due to perceived advantages; such as being lightweight, low-cost and because of the unlimited materials resource. The power conversion efficiency of state-of-the-art PSCs has increased dramatically in the past few years, obtained mainly through the development of new electron donor polymers, acceptors, and novel device structures through the use of various electrode interfacial materi...

  5. Enhanced electrochemical properties of Al2O3-coated LiV3O8 cathode materials for high-power lithium-ion batteries

    Science.gov (United States)

    Huang, S.; Tu, J. P.; Jian, X. M.; Lu, Y.; Shi, S. J.; Zhao, X. Y.; Wang, T. Q.; Wang, X. L.; Gu, C. D.

    2014-01-01

    Surface modified-LiV3O8 cathode materials with Al2O3 are successfully synthesized via a facile thermolysis process. The 0.5 wt.% Al2O3-coated LiV3O8 exhibits an enhanced cyclic stability at various charge-discharge current densities. At a current density of 100 mA g-1, it delivers an initial specific discharge capacity of 283.1 mAh g-1 between 2.0 and 4.0 V. Moreover, high capacities of 139.4 and 118.5 mAh g-1 are obtained at the 100th cycle at current densities of 2000 and 3000 mA g-1, respectively. The improved electrochemical performance is attributed to the Al2O3 coating, which can hinder the irreversible phase transformation and act as a protective layer to prevent the active material from direct contact with electrolyte. Furthermore, the formation of a Li-V-Al-O solid solution at the LiV3O8/Al2O3 interface provides a fast Li+ diffusion path which is of benefit to the electrochemical behaviors.

  6. AlF3-coated LiMn2O4 as cathode material for aqueous rechargeable lithium battery with improved cycling stability

    Science.gov (United States)

    Tron, Artur; Park, Yeong Don; Mun, Junyoung

    2016-09-01

    In this study, we introduce AlF3-coated LiMn2O4 cathodes, which are cost-effective and environmentally benign, for use in the aqueous rechargeable lithium-ion battery. The homogeneous AlF3 coating on the LiMn2O4 powder is synthesized by a simple chemical deposition method. The thickness of the coating is controlled by varying the quantity of AlF3 used, in order to optimize the balance between polarization and surface stabilization. The optimized LiMn2O4, having 2 wt% coating of AlF3, exhibits a long cycle life having a capacity retention of 90% after 100 cycles, and a highly improved rate capability, when compared with the pristine LiMn2O4 material, in 1 M Li2SO4 aqueous electrolyte solution. The systematic surface analyses, comprising scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical analyses, indicate that the AlF3 coating on the LiMn2O4 surface successfully reduces the surface deterioration of LiMn2O4 caused by side reactions between the electrolyte solution and the active material.

  7. Praseodymium-deficiency Pr0.94BaCo2O6-δ double perovskite: A promising high performance cathode material for intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Meng, Fuchang; Xia, Tian; Wang, Jingping; Shi, Zhan; Zhao, Hui

    2015-10-01

    Praseodymium-deficiency Pr0.94BaCo2O6-δ (P0.94BCO) double perovskite has been evaluated as a cathode material for intermediate-temperature solid oxide fuel cells. X-ray diffraction pattern shows the orthorhombic structure with double lattice parameters from the primitive perovskite cell in Pmmm space group. P0.94BCO has a good chemical compatibility with Ce0.9Gd0.1O1.95 (CGO) electrolyte even at 1000 °C for 24 h. It is observed that the Pr-deficiency can introduce the extra oxygen vacancies in P0.94BCO, further enhancing its electrocatalytic activity for oxygen reduction reaction. P0.94BCO demonstrates the promising cathode performance as evidenced by low polarization are-specific resistance (ASR), e. g. 0.11 Ω cm2 and low cathodic overpotential e. g. -56 mV at a current density of -78 mA cm-2 at 600 °C in air. These features are comparable to those of the benchmark cathode Ba0.5Sr0.5Co0.8Fe0.2O3-δ. The fuel cell CGO-Ni|CGO|P0.94BCO presents the attractive peak power density of 1.05 W cm-2 at 600 °C. Furthermore, the oxygen reduction kinetics of P0.94BCO material is also investigated, and the rate-limiting steps for oxygen reduction reaction are determined.

  8. Comparison of LiV3O8 cathode materials prepared by different methods

    DEFF Research Database (Denmark)

    West, Keld; Zachau-Christiansen, Birgit; Skaarup, Steen;

    1996-01-01

    (xerogels) to remove loosely bound water they show a high capacity for lithium insertion, approaching four additional lithium per formula unit, and good reversibility as electrode materials for high energy density lithium cells. How the heat-treatment temperature influences the crystal structure...... is demonstrated as well as the electrochemical properties of the vanadium oxide....

  9. High-rate Lithium Iron(Ⅱ)Phosphate as Cathode Material for Rechargeable Lithium Batteries

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ming; JIAO Li-Fang; YUAN Hua-Tang; SUN Jun-Li; FENG Yan

    2008-01-01

    High-rate carbon coated LiFePO4 was synthesized by citric acid assistant aqueous chemical route employing polyethyleneoxide as the carbon source.The structural and electrochemical properties were intensively investigated by thermogravimetry,powder X-ray diffraction,scanning electron microscopy,transmission electron microscopy,cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge-discharge tests.The results of structural tests showed that the material consisted of small LiFePO4 particles of good phase purity and the particles of the material were coated and connected with approximate 5 wt% incompact porous carbon.The material performed very well in electrochemical measurements,and was suitable for high-rate charge and discharge.The material exhibited stable discharge capacities of 120,90 and 60mAh·g-1 at 5C,10C and 20C rates respectively(1 C=150mA·g-1,charge at 1 C).

  10. 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...

  11. Synthesis of LiFePO4/Pani/C composite as a cathode material for lithium ion battery

    Science.gov (United States)

    Rahayu, Iman; Hidayat, Sahrul; Aryadi, Lutfi

    2016-02-01

    In recent years, LiFePO4 studied intensively as a cathode material for Li-ion batteries because of high theoretical capacity, stability, and environmental friendly. However, its low intrinsic electronic conductivity. One way to improve its conductivity is addition of conductive material. Polyaniline (PANI) is one of the conductive polymer materials that widely studied because its unique physical and chemical properties which can be an insulator and conductor by doping-dedoping processes and has large potential application. The purpose of this research is to improve the conductivity of LiFePO4 with conductive polymer PANI. The method is performed by the addition of LiFePO4 during the polymerization process to form LiFePO4 polyaniline then added to the C-PANI with the addition of mass percent variation of 5%, 10%, 15%, 20% form-LiFePO4 composite PANI-C. In LiFePO4 added during polymerization PANI provide a smooth surface profile after composited with the carbon to LiFePO4-PANI-C compared to LiFePO4-C. LiFePO4-PANI-C composite provided higher conductivity is 18.45×10-4 S/cm compared to LiFePO4-C is 10.48×10-4 S/cm at 20% addition of carbon. This is due to PANI in LiFePO4 is added to the polyaniline polymerization process can act as a conductive adhesive to glue between carbon and LiFePO4.

  12. 81.114- University Reactor Infrastructure and Education Support / Prompt Gamma-ray Activation Analysis of Lithioum Ion Battery Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Manthiram, Arumugam; Landsberger, S.

    2006-11-11

    This project focuses on the use of the Prompt Gamma-ray Activation Analysis (PGAA) technique available at the Nuclear Engineering Teaching Laboratory of the University of Texas at Austin to precisely determine the hydrogen (proton) contents in layered oxide cathode samples obtained by chemical lithium extraction in order to obtain a better understanding of the factors limiting the practical capacities and overall performance of lithium ion battery cathodes. The project takes careful precautionary experimental measures to avoid proton contamination both from solvents used in chemical delithiation and from ambient moisture. The results obtained from PGAA are complemented by the data obtained from other techniques such as thermogravimetric analysis, redox titration, atomic absorption spectroscopy, X-ray diffraction, and mass spectroscopic analysis of the evolved gas on heating. The research results broaden our understanding of the structure-property-performance relationships of lithium ion battery cathodes and could aid the design and development of new better performing lithium ion batteries for consumer (portable and electric vehicles), military, and space applications.

  13. A new high-performance cathode material for rechargeable lithium-ion batteries: Polypyrrole/vanadium oxide nanotubes

    International Nuclear Information System (INIS)

    Polypyrrole/vanadium oxide nanotubes (PPy/VOx-NTs) as a new high-performance cathode material for rechargeable lithium-ion batteries are synthesized by a combination of hydrothermal treatment and cationic exchange technique. The morphologies and structures of the as-prepared samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry and differential scanning calorimeter (TG-DSC) and X-ray powder diffraction (XRD). The results indicate that the organic templates are mainly substituted by the conducting polymer polypyrrole without destroying the previous nanotube structure. Their electrochemical properties are evaluated via galvanostatic charge/discharge cycling, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is found that PPy/VOx-NTs exhibit high discharge capacity and excellent cycling performance at different current densities compared to vanadium oxide nanotubes (VOx-NTs). After 20 cycles, the reversible capacity of PPy/VOx-NTs (159.5 mAh g-1) at the current density of 80 mA g-1 is about four times of magnitude higher than that of VOx-NTs (37.5 mAh g-1). The improved electrochemical performance could be attributed to the enhanced electronic conductivity and the improved structural flexibility resulted from the incorporation of the conducting polymer polypyrrole.

  14. A new high-performance cathode material for rechargeable lithium-ion batteries: Polypyrrole/vanadium oxide nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cui Chaojun, E-mail: tjccj2008@yahoo.com.c [Pohl Institute of Solid State Physics, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Tongji University, No. 1239 Siping Road, Shanghai 200092 (China); Wu Guangming, E-mail: wugm@tongji.edu.c [Pohl Institute of Solid State Physics, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Tongji University, No. 1239 Siping Road, Shanghai 200092 (China); Yang Huiyu; She Shifeng; Shen Jun; Zhou Bin; Zhang Zhihua [Pohl Institute of Solid State Physics, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Tongji University, No. 1239 Siping Road, Shanghai 200092 (China)

    2010-12-01

    Polypyrrole/vanadium oxide nanotubes (PPy/VOx-NTs) as a new high-performance cathode material for rechargeable lithium-ion batteries are synthesized by a combination of hydrothermal treatment and cationic exchange technique. The morphologies and structures of the as-prepared samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry and differential scanning calorimeter (TG-DSC) and X-ray powder diffraction (XRD). The results indicate that the organic templates are mainly substituted by the conducting polymer polypyrrole without destroying the previous nanotube structure. Their electrochemical properties are evaluated via galvanostatic charge/discharge cycling, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is found that PPy/VOx-NTs exhibit high discharge capacity and excellent cycling performance at different current densities compared to vanadium oxide nanotubes (VOx-NTs). After 20 cycles, the reversible capacity of PPy/VOx-NTs (159.5 mAh g{sup -1}) at the current density of 80 mA g{sup -1} is about four times of magnitude higher than that of VOx-NTs (37.5 mAh g{sup -1}). The improved electrochemical performance could be attributed to the enhanced electronic conductivity and the improved structural flexibility resulted from the incorporation of the conducting polymer polypyrrole.

  15. Three-dimensional graphene/LiFePO4 nanostructures as cathode materials for flexible lithium-ion batteries

    International Nuclear Information System (INIS)

    Graphical abstract: Graphene/LiFePO4 composites as a high-performance cathode material for flexible lithium-ion batteries have been prepared by using a co-precipitation method to synthesize graphene/LiFePO4 powders as precursors and then followed by a solvent evaporation process. - Highlights: • Flexible LiFePO4/graphene films were prepared first time by a solvent evaporation process. • The flexible electrode exhibited a high discharge capacity without conductive additives. • Graphene network offers the electrode adequate strength to withstand repeated flexing. - Abstract: Three-dimensional graphene/LiFePO4 nanostructures for flexible lithium-ion batteries were successfully prepared by solvent evaporation method. Structural characteristics of flexible electrodes were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrochemical performance of graphene/LiFePO4 was examined by a variety of electrochemical testing techniques. The graphene/LiFePO4 nanostructures showed high electrochemical properties and significant flexibility. The composites with low graphene content exhibited a high capacity of 163.7 mAh g−1 at 0.1 C and 114 mAh g−1 at 5 C without further incorporation of conductive agents

  16. A Na3V2(PO4)3 cathode material for use in hybrid lithium ion batteries.

    Science.gov (United States)

    Song, Weixin; Ji, Xiaobo; Pan, Chengchi; Zhu, Yirong; Chen, Qiyuan; Banks, Craig E

    2013-09-14

    A NASICON-structure Na3V2(PO4)3 cathode material prepared by carbothermal reduction method is employed in a hybrid-ion battery with Li-involved electrolyte and anode. The ion-transportation mechanism is firstly investigated in this complicated system for an open three-dimensional framework Na3V2(PO4)3. Ion-exchange is greatly influenced by the standing time, for example, the 1 hour battery presents a specific capacity of 128 mA h g(-1) while the 24 hour battery exhibits a value of 148 mA h g(-1) with improved rate and cycling performances over existing literature reported Li-ion batteries. In the hybrid-ion system, an ion-exchange process likely takes place between the two Na(2) sites in the rhombohedral structure. NaLi2V2(PO4)3 could be produced by ion-transportation since the Na(+) in the Na(1) site is stationary and the three Na(2) sites could be used to accommodate the incoming alkali ions; Li(x)Na(y)V2(PO4)3 would come out when the vacant site in Na(2) was occupied depending on the applied voltage range. The reported methodology and power characteristics are greater than those previously reported.

  17. 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.

  18. Rare Earth Elements-Doped LiCoO2 Cathode Material for Lithium-Ion Batteries

    Institute of Scientific and Technical Information of China (English)

    魏进平; 曹晓燕; 潘桂玲; 叶茂; 阎杰

    2003-01-01

    Some compounds of LiCo1-xRExO2 (RE=rare earth elements and x=0.01~0.03) were prepared by doping rare earth elements to LiCoO2 via solid state synthesis. The microstructure characteristics of the LiCo1-xRExO2 were investigated by XRD. It was found that the lattice parameters c are increased and the lattice volumes are enlarged compared to that of LiCoO2. Moreover, the performance of LiCo1-xRExO2 as the cathode material in lithium ion battery is improved, especially LiCo1-xYxO2 and LiCo1-xLaxO2. The initial charge/discharge capacities of LiCo0.99Y0.01O2 and LiCo0.99La0.01O2 are 174/154 (mAh*g-1) and 159/149 (mAh*g-1) respectively, while those for LiCoO2 working in the same way are only 139/131 (mAh*g-1).

  19. Chemical States of Lanthanum in Carbonized La2O3-Mo Thermionic Cathode Materials

    Institute of Scientific and Technical Information of China (English)

    王金淑; 周美玲; 王亦曼; 张久兴; 聂祚仁; 左铁镛

    2003-01-01

    The chemical reaction between lanthanum oxide and molybdenum carbide was studied by thermodynamic calculation, thermal analysis and in-situ X-ray Photoelectron Spectroscopy. The theoretical results show that at the environment allowing for the evaporation of lanthanum, such as in high vacuum, La2O3 in the La2O3-Mo materials can be reduced to metallic lanthanum by molybdenum carbide (Mo2C). To confirm the conclusion, many analysis methods such as XRD, SPS, and TG-DTA were taken. The experimental results show that the chemical state of lanthanum changes during heating. It was proved, for the first time, that reacted metallic lanthanum appears at the surface of this kind of material at high temperature.

  20. 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.

  1. Novel one-step synthesis of wool-ball-like Ni-carbon nanotubes composite cathodes with favorable electrocatalytic activity for hydrogen evolution reaction in alkaline solution

    Science.gov (United States)

    Chen, Zhouhao; Ma, Zhipeng; Song, Jianjun; Wang, Lixin; Shao, Guangjie

    2016-08-01

    In this work, supergravity fields are performed to prepare Ni-CNTs composite cathodes with wool-ball-like morphology from the Watts bath containing well-distributed functionalized CNTs. The prepared Ni-CNTs composite cathodes are used as noble metal-free electrocatalyst with favorable electrocatalytic activity for hydrogen evolution reaction (HER) in alkaline solutions. The crystal structure and morphology of the composite cathodes are characterized by XRD and SEM measurements. The electrochemical activities of the cathodes are characterized through Tafel polarization measurement, electrochemical impedance spectroscopy and cyclic voltammetric study in 1.0 M NaOH solution. The results indicate that catalytic activities of the Ni-CNTs cathodes prepared under supergravity fields are enhanced significantly, and the sample prepared at rotating speed 3000 rpm from the bath containing 1 g dm-3 CNTs exhibits the highest HER activity with smallest Tafel slope and largest exchange current density of 823.9 μA cm-2. Furthermore, the effects of both the CNTs concentrations and the intensities of supergravity fields on the properties of the Ni-CNTs cathodes are investigated.

  2. Ab initio study of vacancy formation in cubic LaMnO3 and SmCoO3 as cathode materials in solid oxide fuel cells

    Science.gov (United States)

    Olsson, Emilia; Aparicio-Anglès, Xavier; de Leeuw, Nora H.

    2016-07-01

    Doped LaMnO3 and SmCoO3 are important solid oxide fuel cell cathode materials. The main difference between these two perovskites is that SmCoO3 has proven to be a more efficient cathode material than LaMnO3 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 LaMnO3 has been widely studied, ab initio studies on SmCoO3 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 SmCoO3 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 SmCoO3, but barely affect LaMnO3. 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.

  3. Studies on Relationship Between Structure of Over-Charge State and Thermal Stability for LiNiO2 Based Cathode Materials

    International Nuclear Information System (INIS)

    A synchrotrons x-ray source was used for In Situ x-ray diffraction studies on cathode materials during charge and discharge. Two new cathode materials, LiNi0.75Mg0.125Ti0.125O2 and LiNi0.56Co0.25Mg0.05Ti0.05O2, were studied in comparison with LiNiO2, and LiCo0.2Ni0.8O2. The relationship between the structural changes and thermal stability at over-charged state has been investigated. For the W time, The thermal stability of these materials are related to their structural changes during charge, especially to the formation of a hexagonal phase H3 with collapsed lattice along ''c'' axis. A hypothesis is proposed that through suppressing the formation of H3 phase when charged above 4.3 V, the thermal stability of the cathode materials can be improved

  4. High-power LiFePO{sub 4} cathode materials with a continuous nano carbon network for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jin-Ming; Hsu, Chia-Haw; Lin, Yu-Run; Hsiao, Mei-Hui [Material Chemical Laboratories, Industrial Technology Research Institute, Hsinchu 310 (China); Fey, George Ting-Kuo [Department of Chemical and Materials Engineering, National Central University, Chung-Li 320 (China)

    2008-10-01

    To meet the requirements of high-power products (ex. electric scooters, hybrid electric vehicles, pure electric vehicles and robots), high-energy safe lithium-ion batteries need to be developed in the future. This research will focus on the microstructures and electrochemical properties of olivine-type LiFePO{sub 4} cathode materials. The morphologies of LiFePO{sub 4}/C composite materials show spherical-type particles and have good carbon conductive networks. From the TEM bright field image and EELS mapping, the LiFePO{sub 4}/C powder shows continuous, dispersive nano-carbon network. These structures will improve electron transfer and lithium-ion diffusion for LiFePO{sub 4} cathode materials, and increase their conductivity from 10{sup -9} S cm{sup -1} to 10{sup -3} S cm{sup -1}. The electrochemical properties of LiFePO{sub 4}/C cathode material in this work demonstrated high rate capability ({>=}12 C) and long cycle life ({>=}700 cycles at a 3 C discharge rate). (author)

  5. Synthesis and Electrochemical Properties of Nanostructured Cathode Materials for Lithium Batteries

    Institute of Scientific and Technical Information of China (English)

    Jaephil; Cho

    2007-01-01

    1 Results For electrode materials in lithium batteries,a high surface area can provide higher electrode/electrolyte contact areas,thus eventually causing the shorter diffusion paths with the particles,and provides more facile intercalation for Li ions[1-4].In addition,reduced strain of intercalation and contributions from charge storage at the surface may also contribute to Li capacity,compared with bulk counterparts.In this regard,I am going to talk about the preparation and electrochemical properties o...

  6. Synthesis, Characterization and Properties of LiFePO4/C Cathode Material

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xin-wen; ZHAN Dan; WANG Li-na; LIU Qiao-yun; ZONG Hong-xing; ZHANG Ke-li

    2005-01-01

    Lithium iron phosphate coated with carbon(LiFePO4/C) was synthesized by improved solid-state reaction using comparatively lower temperature and fewer sintering time. The carbon came from citric acid, which acted as a new carbon source. It was characterized by thermogravimetry and differential thermal analysis (TG/DTA), X ray diffractometer (XRD), Element Analysis (EA) and Scanning electron microscope (SEM). We also studied the electrochemical properties of the material. The first discharge capacity of the and retained 95 % of the initial capacity after 100 cycles. The LiFePO4/C obtained shows a good electrochemical capacity and cycle ability at a large current density.

  7. 锂离子电池层状正极材料的研究进展%Research Process on Layer Cathode Material for Li-ion Batteries

    Institute of Scientific and Technical Information of China (English)

    杨世霞

    2012-01-01

    The paper mainly introduced the research process on layer cathode materials- LiCoO2, LiNiO2, Li MnO2 at present. The advantages and disadvantages of the three layer cathode materials were displayed, and also ways of the modification of LiCoO2 and LiNiO2: doping and coating. The structure and the properties of the layer cathode materials are prompted severely through modification which pointed out a way for the more widely apply of Li-ion batteries. What was more, I showed a prospect of apply of the cathode materials on Li-ion batteries.%文絮主要综述当前锂离子电池层状正极材料-LiCoO2、LiNiO2、LiMnO2的研究进展。阐述了三种层状盐结构正极材料的优缺点,对LiCoO2和LiNiO2正极材料的改性方法:掺杂和包覆处理。通过改性,层状正极材料豹结构和性能均有较大改善,为锂离子电池更为广泛的工业应用指明道路。对锂离子电池正极材料未来的应用前景做了一些展槊。

  8. Synthesis and electrochemical performance of lithium vanadium phosphate and lithium vanadium oxide composite cathode material for lithium ion batteries

    Science.gov (United States)

    Li, Y.; Bai, W. Q.; Zhang, Y. D.; Niu, X. Q.; Wang, D. H.; Wang, X. L.; Gu, C. D.; Tu, J. P.

    2015-05-01

    A novel 2Li3V2(PO4)3·LiV3O8 composite with short rod and thin plate shapes is synthesized through sol-gel method followed by hydrothermal and solid-state reaction. LiV3O8 is used as an additive to improve the capacity of Li3V2(PO4)3. In the composite cathode, active impurity phase Li0.3V2O5 is also present, which has little impact on the whole electrochemical properties. The 2Li3V2(PO4)3·LiV3O8 composite delivers a high initial capacity of 162.8 mAh g-1 at a current density of 100 mA g-1 in the voltage range of 2.0-4.3 V. Furthermore, the composite with high crystallinity also shows high electrochemical reversibility and good rate capability. The diffusion coefficient of Li ions in the composite is in the range of 10-11-10-9 cm2 s-1 obtained from galvanostatic intermittent titration technique.

  9. Preparation, structure study and electrochemistry of layered H2V3O8 materials: High capacity lithium-ion battery cathode

    Science.gov (United States)

    Sarkar, Sudeep; Bhowmik, Arghya; Pan, Jaysree; Bharadwaj, Mridula Dixit; Mitra, Sagar

    2016-10-01

    The present study explores H2V3O8 as high capacity cathode material for lithium-ion batteries (LIB's). Despite having high discharge capacity, H2V3O8 material suffers from poor electrochemical stability for prolonged cycle life. Ultra-long H2V3O8 nanobelts with ordered crystallographic patterns are synthesized via a hydrothermal process to mitigate this problem. The growth of the crystal is facile along [001] direction, and the most common surface is (001) as suggested by Wulff construction study. Electrochemical performance of H2V3O8 cathode is tested against Li/Li+ at various current rates. At 50 mA g-1current rate, it delivers a discharge capacity of 308 mAh g-1, whereas, at 3000 mA g-1, an initial discharge capacity of 144 mAh g-1 is observed and stabilized at 100 mAh g-1 till 500 cycles. Further, the density functional theory (DFT) based simulations study of both the pristine and lithiated phase of H2V3O8 cathode materials is undertaken. DFT study reveals the presence of hydrogen as hydroxyl unit in the framework of the host. In correlation, the magnetic property of vanadium atoms is examined in detail with through partial density of states (PDOS) calculation during three stage lithiation processes and evaluating various potential steps involved in lithium insertion.

  10. Nitrogen-doped graphene-decorated LiVPO4F nanocomposite as high-voltage cathode material for rechargeable lithium-ion batteries

    Science.gov (United States)

    Cui, Kai; Hu, Shuchun; Li, Yongkui

    2016-09-01

    In this study, nitrogen-doped graphene decorated LiVPO4F cathode material is firstly synthesized via a facile method. Well-dispersed LiVPO4F nanoparticles are embedded in nitrogen-doped graphene nanosheets, forming an effective conducting network. The added nitrogen-doped graphene nanosheets greatly enhance the electronic conductivity and Li-ion diffusion of LiVPO4F sample. When tested as cathode material for rechargeable lithium-ion batteries, the hybrid electrode exhibits superior high-rate performance and long-term cycling stability between 3.0 and 4.5 V. It delivers a large discharge capacity of 152.7 mAhg-1 at 0.1 C and shows a capacity retention of 97.8% after 60 cycles. Moreover, a reversible capacity of 90.1 mAhg-1 is maintained even after 500 cycles at a high rate of 20 C. The charge-transfer resistance of LiVPO4F electrode is also reduced in the nitrogen-doped graphene, revealing that its electrode-electrolyte complex reactions take place easily and thus improve the electrochemical performance. The above results provide a facile and effective strategy for the synthesis of LiVPO4F cathode material for high-performance lithium-ion batteries.

  11. In quest of cathode materials for Ca ion batteries: the CaMO3 perovskites (M = Mo, Cr, Mn, Fe, Co, and Ni).

    Science.gov (United States)

    Arroyo-de Dompablo, M E; Krich, C; Nava-Avendaño, J; Palacín, M R; Bardé, F

    2016-07-20

    Basic electrochemical characteristics of CaMO3 perovskites (M = Mo, Cr, Mn, Fe, Co, and Ni) as cathode materials for Ca ion batteries are investigated using first principles calculations at the Density Functional Theory level (DFT). Calculations have been performed within the Generalized Gradient Approximation (GGA) and GGA+U methodologies, and considering cubic and orthorhombic perovskite structures for CaxMO3 (x = 0, 0.25, 0.5, 0.75 and 1). The analysis of the calculated voltage-composition profile and volume variations identifies CaMoO3 as the most promising perovskite compound. It combines good electronic conductivity, moderate crystal structure modifications, and activity in the 2-3 V region with several intermediate CaxMoO3 phases. However, we found too large barriers for Ca diffusion (around 2 eV) which are inherent to the perovskite structure. The CaMoO3 perovskite was synthesized, characterized and electrochemically tested, and results confirmed the predicted trends. PMID:27398629

  12. Enhanced rate performance of multiwalled carbon nanotube encrusted olivine type composite cathode material using polyol technique

    Science.gov (United States)

    Muruganantham, R.; Sivakumar, M.; Subadevi, R.

    2015-12-01

    Olivine type multi-walled carbon nanotube encrusted LiFePO4/C composites have been prepared using economic and energy efficient simple polyol technique without any subsequent heat treatment. The prepared material has an olivine type orthorhombic phase. Also, the iron oxidation state is 2+, which is identified by X-ray diffraction and X-ray photoelectron spectroscopy. It is possible to attain the discharge capacity almost close to theoretical capacity of LiFePO4 as in high temperature methods with ∼100% coulombic efficiency. The specific surface area has been increased upon encrusting multi walled carbon nano tube on LiFePO4/C, which results in enhanced reversible capacity upto 166 mAh g-1 at C/10. Also, it exhibits 89 mAh g-1 even at 30 C rate. This is due to the formation of conductive networks by carbon nanotube, and excellent attachment of LiFePO4/C composite particles on multi-walled carbon nanotube, which induced the kinetics during intercalation/deintercalation process. Multi-walled carbon nanotube acts as the electro-conductive filler on the LiFePO4 surface. The direct addition of MWCNT would result better performances than blending the MWCNT with LiFePO4/C.

  13. Influence of Sc3+ on LiMn2O4 cathode materials at elevated temperature

    Institute of Scientific and Technical Information of China (English)

    LIU Huiyong; DENG Ganqun; GUO Yonglang

    2008-01-01

    Sc3+-doped lithium manganese oxides were synthesized by solid-state reaction. The influences of doping element on structure,mean valence of manganese, and electrochemical performances were studied by X-ray diffraction (XRD), galvanostatic charge-discharge and cyclic voltammetric tests, and also electrochemical impedance spectroscopy (EIS). XRD tests showed that doped lithium manganese oxides were pure spinel structure without other phases. Redox titration and visible spectrophotometry tests indicated that the mean valence of man-ganese in doped lithium manganese oxides was higher than that of pure one. LiSc0.02Mn1.98O4 remained 92.9% of the initial specific discharge capacity after 50th cycle at a constant current of 50 m/g, and the reversibility of LiSc0.02Mn1.98O4 was improved in comparison with pure LiMn2O4 at 50 ℃. EIS indicated that film deposition on spinel particles was suppressed because of Sc3+ doping, and the charge transfer be-tween the surface film and spinel particles with increasing temperature for Sc3+-doped materials became easier as compared with undoped one.

  14. Cathodic electrophoretic deposition of bismuth oxide (Bi{sub 2}O{sub 3}) coatings and their photocatalytic activities

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xiaogang [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Li, Xueming, E-mail: xueminglicqu@126.com [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Lai, Chuan [School of Chemistry and Chemical Engineering, Sichuan University of Arts and Science, Dazhou 635000 (China); Li, Wulin [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Key Laboratory of Optoelectronic Technology and Systems (Education Ministry of China), Chongqing University, 400044 (China); Zhang, Daixiong [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Xiong, Zhongshu [School of Foreign Languages and Literature, Chongqing Normal University, Chongqing 401331 (China)

    2015-03-15

    Graphical abstract: Bismuth oxide (Bi{sub 2}O{sub 3}) coating has been prepared by cathodic electrophoretic deposition method and exhibits high photocatalytic activities for the degradation of Rhodamine B. - Highlights: • The nano-Bi{sub 2}O{sub 3} coatings have been firstly successfully fabricated by EPD method. • The EPD deposition mechanism of Bi{sub 2}O{sub 3} coatings is firstly given. • Deposition dynamics are investigated by regulating different deposition times and applied field strengths in detail. • Obtained coating show great photocatalytic activities for the degradation of Rhodamine B. - Abstract: In this study, cathodic electrophoretic deposition (EPD), a low cost, one-step and flexible method, has been successfully developed to prepare bismuth oxide (Bi{sub 2}O{sub 3}) coatings. Stable suspensions consisted of isopropyl alcohol and trace additive-polyethyleneimine. Deposition was achieved on the cathode at applied field strengths of 5–25 V mm{sup −1} using a total solids loading of 0.5–2 g L{sup −1} at ambient temperature and pressure. The deposition mechanism of Bi{sub 2}O{sub 3} coatings was firstly given, and deposition kinetics were investigated in detail. The deposits were characterized qualitatively by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) observation, atomic force microscope (AFM), X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) analysis, respectively. Moreover, the photocatalytic activities of obtained coatings were evaluated through degradation of Rhodamine B under ultraviolet and visible light irradiation.

  15. New materials for Li-ion batteries: synthesis and spectroscopic characterization of Li2(FeMnCo)SiO4 cathode materials

    Science.gov (United States)

    Ferrari, Stefania; Mozzati, Maria Cristina; Lantieri, Marco; Spina, Gabriele; Capsoni, Doretta; Bini, Marcella

    2016-06-01

    Improving cathode materials is mandatory for next-generation Li-ion batteries. Exploring polyanion compounds with high theoretical capacity such as the lithium metal orthosilicates, Li2MSiO4 is of great importance. In particular, mixed silicates represent an advancement with practical applications. Here we present results on a rapid solid state synthesis of mixed Li2(FeMnCo)SiO4 samples in a wide compositional range. The solid solution in the P21/n space group was found to be stable for high iron concentration or for a cobalt content up to about 0.3 atom per formula unit. Other compositions led to a mixture of polymorphs, namely Pmn21 and Pbn21. All the samples contained a variable amount of Fe3+ ions that was quantified by Mössbauer spectroscopy and confirmed by the TN values of the paramagnetic to antiferromagnetic transition. Preliminary characterization by cyclic voltammetry revealed the effect of Fe3+ on the electrochemical response. Further work is required to determine the impact of these electrode materials on lithium batteries.

  16. High insulation foam glass material from waste cathode ray tube panel glass

    DEFF Research Database (Denmark)

    König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

    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...... parameters on the characteristics of foamed glass. CRT panel glass was crushed, milled and sieved below 63 m. Activated carbon used as a foaming agent and MnO2 as an ‘oxidizing’ agent were mixed with glass powders by means of a planetary ball mill. Foaming effect was observed in the temperature range...... 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...

  17. Ca and In co-doped BaFeO3-δ as a cobalt-free cathode material for intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Wang, Jian; Lam, Kwun Yu; Saccoccio, Mattia; Gao, Yang; Chen, Dengjie; Ciucci, Francesco

    2016-08-01

    We report Ba0·95Ca0·05Fe0·95In0·05O3-δ (BCFI), a novel cobalt-free perovskite, as a promising cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). We synthesize this new material, and systematically characterize its lattice structure, thermal stability, chemical composition, electrical conductivity, and oxygen reduction reaction (ORR) activity. The cubic phase of BaFeO3-δ is stabilized by light isovalent and lower-valence substitution, i.e., 5% Ca2+ in the Ba2+ site and 5% In3+ in the Fe3+/Fe4+ site, in contrast with the typical approach of substituting elements of higher valence. Without resorting to co-doping strategy, the phase of BaFe0·95In0·05O3-δ (BFI) is rhombohedral, while Ba0·95Ca0·05FeO3-δ (BCF) is a mixture of the cubic phase together with BaFe2O4 impurities. The structure of BCFI is cubic from room temperature up to 900 °C with a moderate thermal expansion coefficient of 23.2 × 10-6 K-1. Thanks to the large oxygen vacancy concentration and fast oxygen mobility, BCFI exhibits a favorable ORR activity, i.e., we observe a polarization resistance as small as 0.038 Ω cm2 at 700 °C. The significantly enhanced performance, compared with BFI and BCF, is attributed to the presence of the cubic phase and the large oxygen vacancies brought by the isovalent substitution in the A-site and lower-valence doping in the B-site.

  18. 质子导体燃料电池阴极材料的研究及发展概述%The development review of cathode materials for proton conducting solid oxide fuel cells

    Institute of Scientific and Technical Information of China (English)

    赵凌; 夏长荣

    2013-01-01

    Energy crisis and environmental pollutions are the problems which the whole world is now fac-ing for the sustainable development. Solid oxide fuel cells(SOFCs),which have been regarded as keystone for the future energy economy,have received considerable attention for their high energy conversion efficiency and low impact to environment as a mean of generating electricity. Proton conducting solid oxide fuel cells(H-SOFCs) have attracted much attention for their unique characters,such as great efficiency in fuel utilization,high electro-motive force,high ionic transferring numbers and low activation energies for proton conduction. However, compared with oxygen-ion conducting SOFCs(O-SOFCs),the materials and theories on H-SOFC are just inchoate, especially for cathodes of H-SOFC. In H-SOFC,hydrogen is oxidized at the anode to form protons,which migrate through the electrolyte to the cathode,and undergo a half-cell reaction with oxygen to produce water, which makes the cathode reactions more complex compared with those of O-SOFC. Such distinguished characteristic of cathode reactions calls for intensive consideration on reaction mechanism and might lead to some special demands on the cathode materials. This review is focused on the hisrory of cathode materials for H-SOFC. The elec-trochemical performancesandreactionmodelsofdifferentconductionmechanismcathodematerialsaresummarized, providing some useful means and ways for the development and application of cathode materials for H-SOFC.%  能源危机和环境污染是全世界在可持续发展道路中所面临的难题。固体氧化物燃料电池(SOFC)具有高能量转化效率和低污染排放,被认为是未来能源经济的基石。其中,以质子导体作为电解质的固体氧化物燃料电池(H-SOFC)由于具有高燃料利用率、高理论电动势、高离子迁移数以及低传导活化能,因而备受关注。然而,与氧离子导体固体氧化物燃料电池(O-SOFC)相

  19. Electrochemical Properties of Spinel LiMn2O4-d Fd for Cathode Materials of Secondary Lithium-ion Battery

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The spinel LiMn2O4-δ Fδ cathode materials were synthesized by solid-state reaction, with calculated amounts of LiOH·H2O, MnO2(EMD), LiF. The results of electrochemical test demonstrated that these new materials exhibited excellent electrochemical properties. Its initial capacity reached ~115 mAh·g-1 and reversible efficiency is about 100%. After 60 cycles, its capacity was still around 110 mAh·g-1, with nearly 100% reversible efficiency.

  20. High catalytic activity and pollutants resistivity using Fe-AAPyr cathode catalyst for microbial fuel cell application

    Science.gov (United States)

    Santoro, Carlo; Serov, Alexey; Villarrubia, Claudia W. Narvaez; Stariha, Sarah; Babanova, Sofia; Artyushkova, Kateryna; Schuler, Andrew J.; Atanassov, Plamen

    2015-11-01

    For the first time, a new generation of innovative non-platinum group metal catalysts based on iron and aminoantipyrine as precursor (Fe-AAPyr) has been utilized in a membraneless single-chamber microbial fuel cell (SCMFC) running on wastewater. Fe-AAPyr was used as an oxygen reduction catalyst in a passive gas-diffusion cathode and implemented in SCMFC design. This catalyst demonstrated better performance than platinum (Pt) during screening in “clean” conditions (PBS), and no degradation in performance during the operation in wastewater. The maximum power density generated by the SCMFC with Fe-AAPyr was 167 ± 6 μW cm-2 and remained stable over 16 days, while SCMFC with Pt decreased to 113 ± 4 μW cm-2 by day 13, achieving similar values of an activated carbon based cathode. The presence of S2- and showed insignificant decrease of ORR activity for the Fe-AAPyr. The reported results clearly demonstrate that Fe-AAPyr can be utilized in MFCs under the harsh conditions of wastewater.

  1. Assessment of four different cathode materials at different initial pHs using unbuffered catholytes in microbial electrolysis cells

    KAUST Repository

    Ribot-Llobet, Edgar

    2013-03-01

    Nickel foam (NF), stainless steel wool (SSW), platinum coated stainless steel mesh (Pt), and molybdenum disulfide coated stainless steel mesh (MoS 2) electrodes have been proposed as catalysts for hydrogen gas production, but previous tests have primarily examined their performance in well buffered solutions. These materials were compared using two-chamber microbial electrolysis cells (MECs), and linear sweep voltammetry (LSV) in unbuffered saline solutions at two different initial pHs (7 and 12). There was generally no appreciable effect of initial pH on production rates or total gas production. NF produced hydrogen gas at a rate of 1.1 m3 H2/m 3·d, which was only slightly less than that using Pt (1.4 m3 H2/m3·d), but larger than that obtained with SSW (0.52 m3 H2/m3·d) or MoS2 (0.67 m3 H2/m3·d). Overall hydrogen gas recoveries with SSW (29.7 ± 0.5 mL), MoS2 (28.6 ± 1.3 mL) and NF (32.4 ± 2 mL) were only slightly less than that of Pt (37.9 ± 0.5 mL). Total energy recoveries, based on the gas produced versus electrical energy input, ranged from 0.75 ± 0.02 for Pt, to 0.55 ± 0.02 for SSW. An LSV analysis showed no effect of pH for NF and Pt, but overpotentials were reduced for MoS2 and SSW by using an initial lower pH. At cathode potentials more negative than -0.85 V (vs Ag/AgCl), NF had lower overpotentials than the MoS2. These results provide the first assessment of these materials under practical conditions of high pH in unbuffered saline catholytes, and position NF as the most promising inexpensive alternative to Pt.

  2. 钒系磷酸盐锂离子电池正极材料%Vanadium-Based Phosphates as Cathode Materials for Lithium Ion Batteries

    Institute of Scientific and Technical Information of China (English)

    任慢慢; 刘素文; 卢启芳

    2011-01-01

    Nowadays Li ion batteries have been widely used in many fields as power suppliers for mobile equipment.In commercialized Li ion batteries,cathode materials are mainly lithium transition-metal oxides.However,high cost and security problem limit their large-scale use.Phosphate materials,with a rigid phosphate network and remarkable electrochemical and thermal stability,are considered as a substitution for lithium transition-metal oxides.Among the newly-exploited phosphate cathode materials,vanadium-based phosphates,with stable structure and high theoretical specific capacity,have been attracting much research interest.In this review,recent progress is summarized on the vanadium-based phosphate cathode materials for lithium ion batteries,particularly focusing on the structure,preparation methods,and electrochemical performances of this series of materials.Also,the strategies and the corresponding mechanisms are discussed for the improvement of their general performances.%商业化锂离子电池以锂过渡金属氧化物作正极材料,由于安全性等问题限制了其更广泛的应用。在已经研究和开发的众多新型锂离子电池正极材料中,钒系磷酸盐由于具有较高的对锂电位和理论比容量而成为研究热点。本文综述了各种钒系磷酸盐类锂离子电池正极材料的研究现状,重点对各种材料的结构、制备方法和电化学性能进行了总结,并对改善材料综合性能的方法和机理进行了探讨。

  3. Mesoporous carbon-coated LiFePO4 nanocrystals co-modified with graphene and Mg2+ doping as superior cathode materials for lithium ion batteries

    Science.gov (United States)

    Wang, Bo; Xu, Binghui; Liu, Tiefeng; Liu, Peng; Guo, Chenfeng; Wang, Shuo; Wang, Qiuming; Xiong, Zhigang; Wang, Dianlong; Zhao, X. S.

    2013-12-01

    In this work, mesoporous carbon-coated LiFePO4 nanocrystals further co-modified with graphene and Mg2+ doping (G/LFMP) were synthesized by a modified rheological phase method to improve the speed of lithium storage as well as cycling stability. The mesoporous structure of LiFePO4 nanocrystals was designed and realized by introducing the bead milling technique, which assisted in forming sucrose-pyrolytic carbon nanoparticles as the template for generating mesopores. For comparison purposes, samples modified only with graphene (G/LFP) or Mg2+ doping (LFMP) as well as pure LiFePO4 (LFP) were also prepared and investigated. Microscopic observation and nitrogen sorption analysis have revealed the mesoporous morphologies of the as-prepared composites. X-ray diffraction (XRD) and Rietveld refinement data demonstrated that the Mg-doped LiFePO4 is a single olivine-type phase and well crystallized with shortened Fe-O and P-O bonds and a lengthened Li-O bond, resulting in an enhanced Li+ diffusion velocity. Electrochemical properties have also been investigated after assembling coin cells with the as-prepared composites as the cathode active materials. Remarkably, the G/LFMP composite has exhibited the best electrochemical properties, including fast lithium storage performance and excellent cycle stability. That is because the modification of graphene provided active sites for nuclei, restricted the in situ crystallite growth, increased the electronic conductivity and reduced the interface reaction current density, while, Mg2+ doping improved the intrinsically electronic and ionic transfer properties of LFP crystals. Moreover, in the G/LFMP composite, the graphene component plays the role of ``cushion'' as it could quickly realize capacity response, buffering the impact to LFMP under the conditions of high-rate charging or discharging, which results in a pre-eminent rate capability and cycling stability.In this work, mesoporous carbon-coated LiFePO4 nanocrystals further co

  4. Recent progress of sulfur composites as cathode materials for lithium sulfur batteries%锂硫电池正极复合材料研究现状

    Institute of Scientific and Technical Information of China (English)

    杨蓉; 邓坤发; 刘晓艳; 曲冶; 雷京; 任冰

    2015-01-01

    锂硫电池由于其高理论能量密度(2600W·h/kg)而受到了广泛的关注,是极具应用前景的电池体系。硫基正极材料作为锂硫电池的重要组成部分,是提高电池性能的关键。然而锂硫电池还存在一些问题,如硫的利用率低及正极结构的稳定性差等。本文综述了近几年锂硫电池硫正极复合材料的研究现状,分别从硫/碳复合、硫/导电聚合物复合、硫/氧化物复合3个方面进行介绍,指出了未来锂硫电池正极材料要注意结合硫/导电聚合物及硫/氧化物的优势并注重材料结构的设计,向核壳或类核壳结构方向发展的趋势,同时还要提高载硫量,提高循环稳定性,以获得高性能的锂硫电池。%As a promising battery system,lithium-sulfur battery with high theoretical energy density (2600W·h/kg) has attracted great attention. As one of the essential ingredients for lithium-sulfur batteries,sulfur cathode material is the key to improve the performance of batteries. However,there are some serious and unavoidable problems for lithium-sulfur battery,such as low utilization efficiency of sulfur in cathode and poor stability of electrode structure. In this review,the recent progress of sulfur composites as cathode materials for lithium-sulfur batteries is introduced. Cathode materials are divided into three kinds of composites,such as sulfur/carbon,sulfur/polymer and sulfur/oxide composite materials,which are discussed respectively. It is pointed out that the coming development of cathode materials for lithium-sulfur batteries should be focused on the combination of advantages of sulfur/polymer and sulfur/oxide composite materials,and the design of material structure,such as core-shell or core-shell-like structure for cathode materials. At the same time,high sulfur loading and high cycle stability will be good for the performance improvement of lithium-sulfur batteries.

  5. 锂硫电池正极复合材料研究现状%Recent progress of sulfur composites as cathode materials for lithium sulfur batteries

    Institute of Scientific and Technical Information of China (English)

    杨蓉; 邓坤发; 刘晓艳; 曲冶; 雷京; 任冰

    2015-01-01

    As a promising battery system,lithium-sulfur battery with high theoretical energy density (2600W·h/kg) has attracted great attention. As one of the essential ingredients for lithium-sulfur batteries,sulfur cathode material is the key to improve the performance of batteries. However,there are some serious and unavoidable problems for lithium-sulfur battery,such as low utilization efficiency of sulfur in cathode and poor stability of electrode structure. In this review,the recent progress of sulfur composites as cathode materials for lithium-sulfur batteries is introduced. Cathode materials are divided into three kinds of composites,such as sulfur/carbon,sulfur/polymer and sulfur/oxide composite materials,which are discussed respectively. It is pointed out that the coming development of cathode materials for lithium-sulfur batteries should be focused on the combination of advantages of sulfur/polymer and sulfur/oxide composite materials,and the design of material structure,such as core-shell or core-shell-like structure for cathode materials. At the same time,high sulfur loading and high cycle stability will be good for the performance improvement of lithium-sulfur batteries.%锂硫电池由于其高理论能量密度(2600W·h/kg)而受到了广泛的关注,是极具应用前景的电池体系。硫基正极材料作为锂硫电池的重要组成部分,是提高电池性能的关键。然而锂硫电池还存在一些问题,如硫的利用率低及正极结构的稳定性差等。本文综述了近几年锂硫电池硫正极复合材料的研究现状,分别从硫/碳复合、硫/导电聚合物复合、硫/氧化物复合3个方面进行介绍,指出了未来锂硫电池正极材料要注意结合硫/导电聚合物及硫/氧化物的优势并注重材料结构的设计,向核壳或类核壳结构方向发展的趋势,同时还要提高载硫量,提高循环稳定性,以获得高性能的锂硫电池。

  6. Evaluation of low cost cathode materials for treatment of industrial and food processing wastewater using microbial electrolysis cells

    KAUST Repository

    Tenca, Alberto

    2013-02-01

    Microbial electrolysis cells (MECs) can be used to treat wastewater and produce hydrogen gas, but low cost cathode catalysts are needed to make this approach economical. Molybdenum disulfide (MoS2) and stainless steel (SS) were evaluated as alternative cathode catalysts to platinum (Pt) in terms of treatment efficiency and energy recovery using actual wastewaters. Two different types of wastewaters were examined, a methanol-rich industrial (IN) wastewater and a food processing (FP) wastewater. The use of the MoS2 catalyst generally resulted in better performance than the SS cathodes for both wastewaters, although the use of the Pt catalyst provided the best performance in terms of biogas production, current density, and TCOD removal. Overall, the wastewater composition was more of a factor than catalyst type for accomplishing overall treatment. The IN wastewater had higher biogas production rates (0.8-1.8 m3/m3-d), and COD removal rates (1.8-2.8 kg-COD/m3-d) than the FP wastewater. The overall energy recoveries were positive for the IN wastewater (3.1-3.8 kWh/kg-COD removed), while the FP wastewater required a net energy input of -0.7 - 1.2 kWh/kg-COD using MoS 2 or Pt cathodes, and -3.1 kWh/kg-COD with SS. These results suggest that MoS2 is the most suitable alternative to Pt as a cathode catalyst for wastewater treatment using MECs, but that net energy recovery will be highly dependent on the specific wastewater. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  7. In operando study of the high voltage spinel cathode material LiNi(0.5)Mn(1.5)O4 using two dimensional full-field spectroscopic imaging of Ni and Mn.

    Science.gov (United States)

    Bauer, Sondes; de Biasi, Lea; Glatthaar, Sven; Toukam, Leonel; Gesswein, Holger; Baumbach, Tilo

    2015-07-01

    LiNi0.5Mn1.5O4 spinel cathode was studied during the first discharge cycle using combined full field Transmission X-ray Microscopy (TXM) and X-ray Absorption Near Edge Structure Spectroscopy (XANES) techniques to follow the chemical phase transformation as well as the microstructural evolution of cathode materials upon operation within an electrochemical cell. The spatial distribution and electrochemical process of the spinel material with spherical granules of 30 μm and 3 μm crystallite size was investigated. The spectroscopic imaging of the cathode within field of view of 40 × 32 μm(2) and spatial resolution of 40 nm has revealed an increase of the LiNi0.5Mn1.5O4 granule size during lithiation providing an insight into the effect of the particle size and morphology on the electrochemical process. The chemical elemental distribution and the content of the different oxidation states of the two absorbing elements (Ni and Mn) have been determined in operando from the XANES imaging. A gradual increase in the content of the oxidation state Mn(3+) from 8% up to 64% has been recorded during the discharge from 5 V to 2.7 V. The study of the local oxidation reduction behavior of Mn(3+) reveals a reversibility aspect in the local electrochemical reaction of Mn(4+) toward Mn(3+) in areas located in the center of the aggregate as well as in areas closed to the electrolyte. During the discharge process, a mixture of Mn(3+) and Mn(4+) has been detected while only single electron valence states have been found in the case of Ni. Probing the chemical changes during the discharge using two-dimensional XANES reveals spatial differences in the electrochemical activities of the two absorbing elements Ni and Mn. PMID:26051380

  8. Fundamental Investigations and Rational Design of Durable High-Performance SOFC Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [Georgia Inst. of Technology, Atlanta, GA (United States); Ding, Dong [Georgia Inst. of Technology, Atlanta, GA (United States); Wei, Tao [Georgia Inst. of Technology, Atlanta, GA (United States); Liu, Meilin [Georgia Inst. of Technology, Atlanta, GA (United States)

    2016-03-31

    The main objective of this project is to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants, aiming towards the rational design of cathodes with high-performance and enhanced durability by combining a porous backbone (such as LSCF) with a thin catalyst coating. The mechanistic understanding will help us to optimize the composition and morphology of the catalyst layer and microstructure of the LSCF backbone for better performance and durability. More specifically, the technical objectives include: (1) to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants using in situ and ex situ measurements performed on specially-designed cathodes; (2) to examine the microstructural and compositional evolution of LSCF cathodes as well as the cathode/electrolyte interfaces under realistic operating conditions; (3) to correlate the fuel cell performance instability and degradation with the microstructural and morphological evolution and surface chemistry change of the cathode under realistic operating conditions; (4) to explore new catalyst materials and electrode structures to enhance the stability of the LSCF cathode under realistic operating conditions; and (5) to validate the long term stability of the modified LSCF cathode in commercially available cells under realistic operating conditions. We have systematically evaluated LSCF cathodes in symmetrical cells and anode supported cells under realistic conditions with different types of contaminants such as humidity, CO2, and Cr. Electrochemical models for the design of test cells and understanding of mechanisms have been developed for the exploration of fundamental properties of electrode materials. It is demonstrated that the activity and stability of LSCF cathodes can be degraded by the introduction of contaminants. The microstructural and compositional evolution of LSCF

  9. Fundamental Investigations and Rational Design of Durable High-Performance SOFC Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu; Ding, Dong; Wei, Tao; Liu, Meilin

    2016-03-31

    The main objective of this project is to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants, aiming towards the rational design of cathodes with high-performance and enhanced durability by combining a porous backbone (such as LSCF) with a thin catalyst coating. The mechanistic understanding will help us to optimize the composition and morphology of the catalyst layer and microstructure of the LSCF backbone for better performance and durability. More specifically, the technical objectives include: (1) to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants using in situ and ex situ measurements performed on specially-designed cathodes; (2) to examine the microstructural and compositional evolution of LSCF cathodes as well as the cathode/electrolyte interfaces under realistic operating conditions; (3) to correlate the fuel cell performance instability and degradation with the microstructural and morphological evolution and surface chemistry change of the cathode under realistic operating conditions; (4) to explore new catalyst materials and electrode structures to enhance the stability of the LSCF cathode under realistic operating conditions; and (5) to validate the long term stability of the modified LSCF cathode in commercially available cells under realistic operating conditions. We have systematically evaluated LSCF cathodes in symmetrical cells and anode supported cells under realistic conditions with different types of contaminants such as humidity, CO2, and Cr. Electrochemical models for the design of test cells and understanding of mechanisms have been developed for the exploration of fundamental properties of electrode materials. It is demonstrated that the activity and stability of LSCF cathodes can be degraded by the introduction of contaminants. The microstructural and compositional evolution of LSCF cathodes as

  10. Bismuth and niobium co-doped barium cobalt oxide as a promising cathode material for intermediate temperature solid oxide fuel cells

    Science.gov (United States)

    He, Shaofei; Le, Shiru; Guan, Lili; Liu, Tao; Sun, Kening

    2015-11-01

    Perovskite oxides BaBi0.05Co0.95-yNbyO3-δ (BBCNy, 0 ≤ y ≤ 0.2) are synthesized and evaluated as potential cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). Highly charged Nb5+ successfully stabilizes the cubic perovskite structure to room temperature with Nb substituting content y ≥ 0.1. The phase structure, thermal expansion behavior, electrical conductivity and electrochemical performance of BBCNy with cubic phase are systematically studied. The samples exhibit excellent chemical compatibility with GDC and have sufficiently high electrical conductivities. However, the thermal expansion coefficients of BBCNy samples are nearly twice those of the most commonly used electrolyte materials YSZ and GDC, which is a major drawback for application in IT-SOFCs. The polarization resistances of BBCNy with y = 0.10, 0.15 and 0.20 on GDC electrolyte are 0.086, 0.079 and 0.107 Ω cm2 at 700 °C, respectively. Even though the YSZ electrolyte membrane and GDC barrier layer are approximately 50 μm and 10 μm in thickness, the highest maximum power density (1.23 W cm-2) of the single cell Ni-YSZ|YSZ|GDC|BBCN0.15 is obtained at 750 °C. Good long-term stability of the single cell with BBCN0.15 cathode is also demonstrated. These results demonstrate that BBCNy perovskite oxides with cubic structure are very promising cathode materials for IT-SOFCs.

  11. Facile one step synthesis and enhanced electrochemical performance of Molybdenum dioxide and carbon co-modified lithium manganese silicate cathode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Highlights: • MoO2-modified Li2MnSiO4/C cathode materials have been successfully prepared via facile one step sol-gel method. • The cathode material coated with 1 wt% MoO2 exhibits a reversible capacity of 184.9 mA h/g at 0.1C and maintains 127.5 mA h/g even at a high rate of 1C. • Coating 1 wt% MoO2 can reduce the interfacial resistance and significantly improve the lithium ion diffusion coefficient. - Abstract: Through facile one step sol-gel method, Li2MnSiO4-based cathode materials have been successfully synthesized and co-modified with carbon and MoO2 coating. The phase compositions and morphology of the as-prepared products have been characterized by XRD, SEM and TEM. The physical characterization indicates the introduced MoO2 exists on the particle surface of orthorhombic Li2MnSiO4, forming a hybrid coating layer with amorphous carbon. Meanwhile, the addition of MoO2 improves the dispersion of particle size distribution. Therefore, the electrochemical performance of the pristine Li2MnSiO4/C has been significantly improved after coating MoO2, especially in the case of 1 wt% MoO2 component. The optimal as-prepared sample exhibits a reversible capacity of 184.9 mA h/g at 0.1C and maintains 127.5 mA h/g even at a high rate of 1C. The excellent rate performance can be attributed to reduced interfacial resistance and enhanced lithium ion diffusion coefficient

  12. Enhanced rate performance of molybdenum-doped spinel LiNi0.5Mn1.5O4 cathode materials for lithium ion battery

    Science.gov (United States)

    Yi, Ting-Feng; Chen, Bin; Zhu, Yan-Rong; Li, Xiao-Ya; Zhu, Rong-Sun

    2014-02-01

    The Mo-doped LiNi0.5Mn1.5O4 cathodes are successfully synthesized by citric acid-assisted sol-gel method. The result demonstrates that the Mo-doped LiMn1.4Ni0.55Mo0.05O4 cathodes present the improved electrochemical performance over pristine LiNi0.5Mn1.5O4. At the 2 C rate after 80 cycles, the discharge capacities are 68.5 mAh g-1 for the pristine LiNi0.5Mn1.5O4 material (53.9% of the capacity at 0.1 C), 107.4 mAh g-1 for the LiMn1.425Ni0.5Mo0.05O4 material (82.1% at 0.1 C), and 122.7 mAh g-1 for the LiMn1.4Ni0.55Mo0.05O4 material (90.5% at 0.1 C). Mo-doping is favorable for reducing the electrode polarization, suggesting that Mo-doped LiNi0.5Mn1.5O4 electrodes have faster lithium insertion/extraction kinetics during cycling. Mo-doped LiNi0.5Mn1.5O4 electrodes show lower charge-transfer resistance and higher lithium diffusion coefficients. In addition, LiMn1.4Ni0.55Mo0.05O4 cathode exhibits the smallest particle size, the lowest charge-transfer resistance and the highest lithium diffusion coefficient among all samples, indicating that it has a high reversibility and good rate capability.

  13. Electroviscoelastic materials as active dampers

    Science.gov (United States)

    Biggerstaff, Janet M.; Kosmatka, John B.

    2002-07-01

    Electroviscoelastic materials (EVEMs) are polymeric materials that exhibit changes in structural properties when a voltage is applied across it. In the current study, an EVEM is developed that produce large changes in stiffness and damping materials with applied voltage. The resulting material exhibits many of the same properties as an electrorheological (ER) material, except the current material is self-supporting and thus can be used to applications where viscoelastic materials are used. The EVEM is composed of three components: 20% (by mass) of poly (p-phenylene) (PPP) particles doped with CuCl2 or FeCl3, 64% of Dow Sylgard 527 silicone gel, and 16% Dow Corning Sylgard 182 silicone elastomer, where the elastomer is added to for stiffening. Experimental harmonic tests using a double-lap shear test and a 0.025 thick specimens between 1 and 150 Hz reveal a factor six increase in stiffening and a factor of three decrease in damping with applied voltage (1500v).

  14. Synthesis of LiFePO4/Graphene Nanocomposite and Its Electrochemical Properties as Cathode Material for Li-Ion Batteries

    OpenAIRE

    2015-01-01

    LiFePO4/graphene nanocomposite was successfully synthesized by rheological phase method and its electrochemical properties as the cathode materials for lithium ion batteries were measured. As the iron source in the synthesis, FeOOH nanorods anchored on graphene were first synthesized. The FeOOH nanorods precursors and the final LiFePO4/graphene nanocomposite products were characterized by XRD, SEM, and TEM. While the FeOOH precursors were nanorods with 5–10 nm in diameter and 10–50 nm in leng...

  15. La2NiO4+δ Infiltration of Plasma-Sprayed LSCF Coating for Cathode Performance Improvement

    Science.gov (United States)

    Li, Ying; Zhang, Shan-Lin; Li, Cheng-Xin; Wei, Tao; Yang, Guan-Jun; Li, Chang-Jiu; Liu, Meilin

    2016-01-01

    Perovskite-structured (La0.6Sr0.4Co0.2Fe0.8O3) LSCF has been widely studied as a cathode material for intermediate-temperature solid oxide fuel cells. However, the application of LSCF cathode is likely to be limited by its sluggish surface catalytic properties and long-term stability issues. Oxygen hyper-stoichiometric La2NiO4+δ with K2NiF4 structure exhibits higher catalytic properties, ionic conductivity, and stability in comparison with LSCF cathode. Due to the good chemical compatibility of these two cathode materials, it is possible to prepare a composite cathode by the infiltration of La2NiO4+δ in the porous LSCF. This composite structure fully utilizes the advantages of the two cathodes and enhances the LSCF cathode performance. In this study, the LSCF cathode was deposited by using an atmospheric plasma spray technique, and the porous LSCF cathode was then infiltrated by La2NiO4+δ. The atmospheric plasma spray technique was used to reduce the SOFC manufacturing cost. The microstructure of coatings was characterized by SEM and EDS. The cathode polarization resistance was found to decrease by ~40% after the La2NiO4+δ infiltration. Also, the activation energy decreased from 1.53 to 1.40 eV.

  16. Kinetic Behavior of LiFePO4/C Thin Film Cathode Material for Lithium-Ion Batteries

    OpenAIRE

    Kucinskis, G; Bajārs, G; Kleperis, J.; Smits, J.

    2010-01-01

    LiFePO4 was prepared in a solid state synthesis with various levels of carbon content. LiFePO4/C thin films were obtained via magnetron sputtering. The surface morphology and structure was examined. Electrochemical properties of LiFePO4/C were studied, by using cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. Thin films acquired show a potential use as a cathode in lithium ion batteries, displaying charge capacity up to 34 mAh g-1.

  17. Organic active materials for batteries

    Energy Technology Data Exchange (ETDEWEB)

    Abouimrane, Ali; Weng, Wei; Amine, Khalil

    2016-08-16

    A rechargeable battery includes a compound having at least two active sites, R.sup.1 and R.sup.2; wherein the at least two active sites are interconnected by one or more conjugated moieties; each active site is coordinated to one or more metal ions M.sup.a+ or each active site is configured to coordinate to one or more metal ions; and "a" is 1, 2, or 3.

  18. 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.

  19. 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

  20. Electrochemical studies on Li+/K+ ion exchange behaviour in K4Fe(CN)6 cathode material for Li, K-ion battery

    Indian Academy of Sciences (India)

    Bikash Mandal; I Basumallick; Susanta Ghosha

    2015-01-01

    The electrochemical studies of anhydrous K4Fe(CN)6 is reported. Anhydrous material was produced after dehydrating K4Fe(CN)6.3H2O crystal at 200°C in an open atmosphere. The material, as obtained, was characterized by various spectroscopic techniques, such as UV-Visible, FTIR, powder X-ray diffraction and FESEM-EDX. Electrochemical and Li+/K+ ion exchange behaviour of the synthesized material were studied by cyclic voltametry (CV), chronoamperometry (CA) and galvanostatic charge-discharge method after preparing a laboratory model cell against lithium anode instead of potassium. During anodic scan in the 1st cycle, peak maximum was observed at 3.93 V vs. Li+/Li due to removal of K+ ions from the ferrocyanide matrix, whereas, in the reverse scan (cathodic sweep) as well as in consequent cycles, peak maxima due to Li+ ion insertion and extraction were observed at 2.46 V and 3.23 V vs. Li+/Li, respectively. Cell, assembled using ferrocyanide cathode and lithium anode, shows an open circuit potential of 3.08 V and delivers a maximum capacity of 61 mAh g-1 (theoretical capacity 72 mAh g-1) at a rate of 0.2 C at room temperature.

  1. Research and Development of Spherical Cathode Materials for Lithium Ion Battery%锂离子电池球形正极材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    李军; 周燕; 靳世东; 郑育英

    2011-01-01

    球形化可以提高锂离子正极材料的压实密度、体积比容量并改善其加工性能和极片的质量.简要介绍了球形材料的特点,综述了球形LiCoO、LiNiMO、LiMnO、LiFeP0等的制备及其性能,展望了球形正极材料的应用前景.%Sphericition has become the important development direction of lithium-ion battery cathode materials. Because they have high energy density and excellent electrochemistry capability,manufacturing performance and so on. Basic characteristics of spherical materials are introduced briefly. New progress of lithium ion battery spherical cathode materials were summarized during recent years, including LiCoO2, LiNixM1-xO2, LiMn2O4 and LiFePO4 and so on.

  2. Alkaline activation of ceramic waste materials

    OpenAIRE

    REIG CERDÁ, LUCÍA; Tashima, M. M.; Soriano, L.; Borrachero, M. V.; Monzó, J.; Payá, J.

    2013-01-01

    Ceramic materials represent around 45 % of construction and demolition waste, and originate not only from the building process, but also as rejected bricks and tiles from industry. Despite the fact that these wastes are mostly used as road sub-base or construction backfill materials, they can also be employed as supplementary cementitious materials, or even as raw material for alkali-activated binders This research aimed to investigate the properties and microstructure of alkali-activated cem...

  3. Polymer–Graphene Nanocomposites as Ultrafast-Charge and -Discharge Cathodes for Rechargeable Lithium Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Song, Zhiping; Xu, Terrence (Tianren); Gordin, Mikhail; Jiang, Yingbing; Bae, In-Tae; Xiao, Qiangfeng; Zhan, Hui; Liu, Jun; Wang, Donghai

    2012-05-09

    Electroactive polymers are a new generation of 'green' cathode materials for rechargeable lithium batteries. We have developed nanocomposites combining graphene with two promising polymer cathode materials, poly(anthraquinonyl sulfide) and polyimide, to improve their high-rate performance. The polymer-graphene nanocomposites were synthesized through a simple in-situ polymerization in the presence of graphene sheets. The highly dispersed graphene sheets in the nanocomposite drastically enhanced the electronic conductivity and allowed the electrochemical activity of the polymer cathode to be efficiently utilized. This allows for ultrafast charging and discharging - the composite can deliver more than 100 mAh/g within just a few seconds.

  4. Synthesis and properties of Li{sub 2}MnO{sub 3}-based cathode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Leigang; Zhang, Shu; Li, Shuli; Lu, Yao; Toprakci, Ozan [Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC 27695-8301 (United States); Xia, Xin [Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC 27695-8301 (United States); College of Textile and Clothing, Xinjiang University, Xinjiang, Urumchi 830046 (China); Chen, Chen [College of Textile and Clothing, Xinjiang University, Xinjiang, Urumchi 830046 (China); Hu, Yi [Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC 27695-8301 (United States); Engineering Research Center for Eco-Dyeing and Finishing of Textiles, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018 (China); Zhang, Xiangwu, E-mail: xiangwu_zhang@ncsu.edu [Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC 27695-8301 (United States)

    2013-11-15

    Highlights: •0.3Li{sub 2}MnO{sub 3}·0.5LiMn{sub 0.5}Ni{sub 0.5}O{sub 2}·0.2LiCoO{sub 2} was synthesized by a co-precipitation method. •The preparation method is simple and this material is inexpensive due to the high contents of Mn and Ni. •The material could be charged to a high potential to extract more lithium without structural damage. •A relatively high capacity of 178 mAh g{sup −1} is delivered between 2.0 and 4.6 V with excellent cycling performance. -- Abstract: Lithium-ion batteries have been wildly used in various portable electronic devices and the application targets are currently moving from small-sized mobile devices to large-scale electric vehicles and grid energy storage. Therefore, lithium-ion batteries with higher energy densities are in urgent need. For high-energy cathodes, Li{sub 2}MnO{sub 3}–LiMO{sub 2} layered–layered (M = Mn, Co, Ni) materials are of significant interest due to their high specific capacities over wide operating potential windows. Here, three Li{sub 2}MnO{sub 3}-based cathode materials with α-NaFeO{sub 2} structure were prepared by a facile co-precipitation method and subsequent heat treatment. Among these three materials, 0.3Li{sub 2}MnO{sub 3}·0.5LiMn{sub 0.5}Ni{sub 0.5}O{sub 2}·0.2LiCoO{sub 2} shows the best lithium storage capability. This cathode material is composed of uniform nanosized particles with diameters ranging from 100 to 200 nm, and it could be charged to a high cutoff potential to extract more lithium, resulting in a high capacity of 178 mAh g{sup −1} between 2.0 and 4.6 V with almost no capacity loss over 100 cycles.

  5. Synthesis, characterization and rate capability performance of the micro-porous MnO{sub 2} nanowires as cathode material in lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    R, Ranjusha; S, Sonia T.; S, Roshny; V, Lakshmi [Nano Solar Division, Amrita Centre for Nanosciences, Kochi 682 041 (India); Kalluri, Sujith [Institute for Superconducting and Electronic Materials, University of Wollongong, New South Wales 2500 (Australia); Kim, Taik Nam [Department of Materials Engineering, Paichai University, Daejeon 302-735 (Korea, Republic of); Nair, Shantikumar V. [Nano Solar Division, Amrita Centre for Nanosciences, Kochi 682 041 (India); Balakrishnan, A., E-mail: avinash.balakrishnan@gmail.com [Nano Solar Division, Amrita Centre for Nanosciences, Kochi 682 041 (India)

    2015-10-15

    Graphical abstract: Translating MnO{sub 2} nanowires as cathode materials in coin cell and studying their discharge behavior and cycling stability at different C-rates. - Highlights: • MnO{sub 2} nanowires have been synthesized via hydrothermal route. • The nanowires were employed as cathode materials in Li-batteries. • Discharge and cycling stability were studied at different C-rates. • Specific capacity and power density of 251 mAh g{sup −1} and 200 W kg{sup −1} were attained. - Abstract: A peculiar architecture of one-dimensional MnO{sub 2} nanowires was synthesized by an optimized hydrothermal route and has been lucratively exploited to fabricate highly efficient microporous electrode overlays for lithium batteries. These fabricated electrodes comprised of interconnected nanoscale units with wire-shaped profile which exhibits high aspect ratio in the order of 10{sup 2}. Their outstanding intercalation/de-intercalation prerogatives have also been studied to fabricate lithium coin cells which revealed a significant specific capacity and power density of 251 mAh g{sup −1} and 200 W kg{sup −1}, respectively. A detailed electrochemical study was performed to elucidate how surface morphology and redox reaction behaviors underlying these electrodes influence the cyclic behavior of the electrode. Rate capability tests at different C-rates were performed to evaluate the capacity and cycling performance of these coin cells.

  6. Influence of thermal-decomposition temperatures on structures and properties of V2O5 as cathode materials for lithium ion battery

    Directory of Open Access Journals (Sweden)

    Yu Chen

    2015-02-01

    Full Text Available Submicron spherical V2O5 particles with a uniform size and a lower crystallinity were successfully synthesized by a chemical precipitation-thermal decomposition technique using the commercial V2O5 powders as starting material. The crystal structure and grain morphology of samples were characterized by X-ray diffraction (XRD and scanning electron microscopy (SEM, respectively. Electrochemical testing such as discharge–charge cycling (CD and cyclic voltammetry (CV were employed in evaluating their electrochemical properties as cathode materials for lithium ion battery. Results reveal that the crystallinity and crystalline size of V2O5 particles increased when the thermal-decomposition temperature increased from 400 °C to 500 °C, and their adhesiveness was also synchronously increased. This indicate that the thermal-decomposition temperature palyed a significant influence on electrochemical properties of V2O5 cathodes. The V2O5 sample obtained at 400 °C delivered not only a high initial discharge capacity of 330 mA h g−1 and also the good cycle stability during 50 cycles due to its higher values of α in crystal structure and better dispersity in grain morphology.

  7. High power nano-LiMn2O4 cathode materials with high-rate pulse discharge capability for lithium-ion batteries

    Institute of Scientific and Technical Information of China (English)

    Chen Ying-Chao; Xie Kai; Pan Yi; Zheng Chun-Man; Wang Hua-Lin

    2011-01-01

    Nano-LiMn2O4 cathode materials with nano-sized particles are synthesized via a citric acid assisted sol-gel route. The structure, the morphology and the electrochemical properties of the nano-LiMn2O4 are investigated. Compared with the micro-sized LiMn2O4, the nano-LiMn2O4 possesses a high initial capacity (120 mAh/g) at a discharge rate of 0.2 C (29.6 mA/g). The nano-LiMn2O4 also has a good high-rate discharge capability, retaining 91% of its capacity at a discharge rate of 10 C and 73% at a discharge rate of 40 C. In particular, the nano-LiMn2O4 shows an excellent high-rate pulse discharge capability. The cut-off voltage at the end of 50-ms pulse discharge with a discharge rate of 80 C is above 3.40 V, and the voltage returns to over 4.10 V after the pulse discharge. These results show that the prepared nano-LiMn2O4 could be a potential cathode material for the power sources with the capability to deliver very high-rate pulse currents.

  8. Synthesis of LiFePO4/Graphene Nanocomposite and Its Electrochemical Properties as Cathode Material for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Xiaoling Ma

    2015-01-01

    Full Text Available LiFePO4/graphene nanocomposite was successfully synthesized by rheological phase method and its electrochemical properties as the cathode materials for lithium ion batteries were measured. As the iron source in the synthesis, FeOOH nanorods anchored on graphene were first synthesized. The FeOOH nanorods precursors and the final LiFePO4/graphene nanocomposite products were characterized by XRD, SEM, and TEM. While the FeOOH precursors were nanorods with 5–10 nm in diameter and 10–50 nm in length, the LiFePO4 were nanoparticles with 20–100 nm in size. Compared with the electrochemical properties of LiFePO4 particles without graphene nanosheets, it is clear that the graphene nanosheets can improve the performances of LiFePO4 as the cathode material for lithium ion batteries. The as-synthesized LiFePO4/graphene nanocomposite showed high capacities and good cyclabilities. When measured at room temperature and at the rate of 0.1C (1C = 170 mA g−1, the composite showed a discharge capacity of 156 mA h g−1 in the first cycle and a capacity retention of 96% after 15 cycles. The improved performances of the composite are believed to be the result of the three-dimensional conducting network formed by the flexible and planar graphene nanosheets.

  9. Improving cycling performance of Li-rich layered cathode materials through combination of Al2O3-based surface modification and stepwise precycling

    Science.gov (United States)

    Kobayashi, Genki; Irii, Yuta; Matsumoto, Futoshi; Ito, Atsushi; Ohsawa, Yasuhiko; Yamamoto, Shinji; Cui, Yitao; Son, Jin-Young; Sato, Yuichi

    2016-01-01

    Controlling a cathode/electrolyte interface by modifying the surface of a cathode material with metal oxides or phosphates is a concept being explored as a possible strategy for improving the electrochemical performance of such materials. This study therefore looks at the crystal structure and chemical bonding state from bulk to surface of Al2O3-coated Li[Li0.2Ni0.18Co0.03Mn0.58]O2 and explores the influence that surface modification has on the electrochemical performance. Investigation by X-ray diffraction, hard X-ray photoelectron spectroscopy (HAXPES) and galvanostatic charge/discharge reaction reveals that the surface-modification layer is composed of Li-Al oxides and Al oxides, with a LiM1-xAlxO2 (M = transition metal) interlayer formed between the modification layer and Li[Li0.2Ni0.18Co0.03Mn0.58]O2 particles. The cycling performance of the Li-rich layered oxide is enhanced by its surface modification with Al2O3, achieving a discharge capacity of more than 310 mA h-1 and excellent cycling stability at 50 °C when combined with a more gradual Li-insertion/de-insertion process (i.e., stepwise precycling treatment).

  10. Activation of porous MOF materials

    Science.gov (United States)

    Hupp, Joseph T; Farha, Omar K

    2013-04-23

    A method for the treatment of solvent-containing MOF material to increase its internal surface area involves introducing a liquid into the MOF in which liquid the solvent is miscible, subjecting the MOF to supercritical conditions for a time to form supercritical fluid, and releasing the supercritical conditions to remove the supercritical fluid from the MOF. Prior to introducing the liquid into the MOF, occluded reaction solvent, such as DEF or DMF, in the MOF can be exchanged for the miscible solvent.

  11. High Cycling Performance Cathode Material: Interconnected LiFePO4/Carbon Nanoparticles Fabricated by Sol-Gel Method

    OpenAIRE

    2014-01-01

    Interconnected LiFePO4/carbon nanoparticles for Li-ion battery cathode have been fabricated by sol-gel method followed by a carbon coating process involving redox reactions. The carbon layers coated on the LiFePO4 nanoparticles not only served as a protection layer but also supplied fast electrons by building a 3D conductive network. As a cooperation, LiFePO4 nanoparticles encapsulated in interconnected conductive carbon layers provided the electrode reactions with fast lithium ions by offer...

  12. Current Status and Prospect of Cathode Materials for Lithium Sulfur Batteries%锂硫电池硫碳复合正极材料研究现状及展望

    Institute of Scientific and Technical Information of China (English)

    周兰; 余爱水

    2015-01-01

    Elemental sulfur has been extensively investigated as a promising candidate of cathode material for next generation lithium secondary batteries.However,some troublesome issues,such as the low electric conductivity of sulfur (5 × 10-30 S· cm-1) and the high solubility of lithium polysulfide intermediates in organic electrolytes,resulting in a low utilization of active material and a redox shuttling of dissolved polysulfide ions between the sulfur cathode and the lithium anode,which eventually leads to a deposition of insoluble and insulating Li2S2/Li2S on the electrode surface and a fast reduction in the specific capacity.Notably,recent results indicate that carbon materials have been regarded as the ideal matrix for sulfur to improve the discharge capacity and cycling performance of lithium-sulfur batteries.In this review,recent development of carbon materials for lithium sulfur batteries is summarized and the prospect on sulfur/carbon composites cathode is discussed.%二次锂硫电池被视为最具有发展潜力的下一代高能量密度二次电池之一.但由于正极硫的电导率低(5×10-30 S·cm-1),且在放电过程中产生的中间体多硫化物易溶于有机电解液,致使锂硫电池活性物质利用率降低,溶解后的多硫化物还会迁移到负极,被还原成不溶物Li2S2/Li2S而沉积于负极锂,使电极结构遭受破坏,造成电池容量大幅衰减,循环性能差,从而限制了进一步的开发应用.研究表明,以碳作为导电骨架的硫碳复合正极材料能在不同程度上解决上述问题,从而有效提高了锂硫电池的放电容量和循环性能.本文综述了近年来国内外报道的各种锂硫电池正极材料的研究进展,结合作者课题组的研究,重点探讨了硫碳复合正极材料,并对其今后的发展趋势进行了展望.

  13. High current density cathode for electrorefining in molten electrolyte

    Science.gov (United States)

    Li, Shelly X.

    2010-06-29

    A high current density cathode for electrorefining in a molten electrolyte for the continuous production and collection of loose dendritic or powdery deposits. The high current density cathode eliminates the requirement for mechanical scraping and electrochemical stripping of the deposits from the cathode in an anode/cathode module. The high current density cathode comprises a perforated electrical insulated material coating such that the current density is up to 3 A/cm.sup.2.

  14. Graphene oxide assisted facile hydrothermal synthesis of LiMn0.6Fe0.4PO4 nanoparticles as cathode material for lithium ion battery

    Institute of Scientific and Technical Information of China (English)

    Changchang Xu; Li Li; Fangyuan Qiu; Cuihua An; Yanan Xu; Ying Wang; Yijing Wang; Lifang Jiao; Huatang Yuan

    2014-01-01

    Assisted by graphene oxide (GO), nano-sized LiMn0.6Fe0.4PO4 with excellent electrochemical performance was prepared by a facile hy-drothermal method as cathode material for lithium ion battery. SEM and TEM images indicate that the particle size of LiMn0.6Fe0.4PO4 (S2) was about 80 nm in diameter. The discharge capacity of LiMn0.6Fe0.4PO4 nanoparticles was 140.3 mAh·g-1 in the first cycle. It showed that graphene oxide was able to restrict the growth of LiMn0.6Fe0.4PO4 and it in situ reduction of GO could improve the electrical conductivity of LiMn0.6Fe0.4PO4 material.

  15. Electrocatalytic Activity and Stability of M-Fe Catalysts Synthesized by Polymer Complex Method for PEFC Cathode

    KAUST Repository

    Ou, Yiwei

    2011-11-01

    The polymerized complex (PC) method was used to synthesize highly dispersed iron-based catalysts for the oxygen reduction reaction (ORR). The catalysts were prepared with an addition of 1,10-phenanthroline (Phen) and transition metals (M), such as Ta, Ti, and W, in an attempt to enhance the ORR activity and durability of the catalysts. The composition and properties of the catalysts were characterized by thermogravimetric analysis, X-ray diffraction, and X-ray photoelectron spectroscopy. The catalyst components, after extensive dissolution in a strong acid solution, were characterized by inductively coupled plasma mass spectroscopy and ultraviolet-visible spectroscopy. It was found that the Ti-Fe catalyst showed improved ORR performance, and the Ta-Fe catalyst showed enhanced stability towards ORR in acidic solution. The catalytic activity and stability for ORR was observed by adding Ti or Ta into the catalyst formulation, suggesting that the interaction between added hetero-ions (Ti and Ta) and ionic Fe active sites was beneficial for the ORR. A single-cell test with the synthesized catalyst in the cathode initially generated a high power density, but the low stability remains an issue to be solved.

  16. A pulsed cathodic arc spacecraft propulsion system

    Science.gov (United States)

    Neumann, P. R. C.; Bilek, M. M. M.; Tarrant, R. N.; McKenzie, D. R.

    2009-11-01

    We investigate the use of a centre-triggered cathodic arc as a spacecraft propulsion system that uses an inert solid as a source of plasma. The cathodic vacuum arc produces almost fully ionized plasma with a high exhaust velocity (>104 m s-1), giving a specific impulse competitive with other plasma or ion thrusters. A centre trigger design is employed that enables efficient use of cathode material and a high pulse-to-pulse repeatability. We compare three anode geometries, two pulse current profiles and two pulse durations for their effects on impulse generation, energy and cathode material usage efficiency. Impulse measurement is achieved through the use of a free-swinging pendulum target constructed from a polymer material. Measurements show that impulse is accurately controlled by varying cathode current. The cylindrical anode gave the highest energy efficiency. Cathode usage is optimized by choosing a sawtooth current profile. There is no requirement for an exhaust charge neutralization system.

  17. Structural and Electrochemical Investigation of Li(Ni0.4Co0.2-yAlyMn0.4)O2 Cathode Material

    Energy Technology Data Exchange (ETDEWEB)

    Rumble, C.; Conry, T.E.; Doeff, Marca; Cairns, Elton J.; Penner-Hahn, James. E.; Deb, Aniruddha

    2010-02-02

    Li(Ni{sub 0.4}Co{sub 0.2-y}Al{sub y}Mn{sub 0.4})O{sub 2} with y=0.05 was investigated to understand the effect of replacement of the cobalt by aluminum on the structural and electrochemical properties. The effect of the substitution was studied by in-situ X-ray absorption spectroscopy (XAS), utilizing a novel in situ electrochemical cell, specifically designed for long-term X-ray experiments. The cell was cycled at a moderate rate through a typical Li-ion battery operating voltage range (1.0-4.7 V). XAS measurements were performed at different states-of-charge (SOC) during cycling, at the Ni, Co, and the Mn edges, revealing details about the response of the cathode to Li insertion and extraction processes. The extended X-ray absorption fine structure region of the spectra revealed the changes of bond distance and coordination number of Ni, Co, and Mn absorbers as a function of the SOC of the material. The oxidation states of the transition metals in the system are Ni{sup 2+}, Co{sup 3+}, and Mn{sup 4+} in the as-made material (fully discharged), while during charging the Ni{sup 2+} is oxidized to Ni{sup 4+} through an intermediate stage of Ni{sup 3+}, Co{sup 3+} is oxidized towards Co{sup 4+} and Mn was found to be electrochemically inactive and remains as Mn{sup 4+}. The EXAFS results during cycling show that the Ni-O changes the most, followed by Co-O and Mn-O varies the least. These measurements on this cathode material confirmed that the material retains its symmetry and good structural short-range order leading to the superior cycling reported earlier.

  18. Structural and electrochemical Investigation of Li(Ni0.4Co0.2-yAlyMn0.4)O2 Cathode Material

    Energy Technology Data Exchange (ETDEWEB)

    Rumble, C.; Conry, T.E.; Doeff, Marca; Cairns, Elton J.; Penner-Hahn, James E.; Deb, Aniruddha

    2010-06-14

    Li(Ni{sub 0.4}Co{sub 0.15}Al{sub 0.05}Mn{sub 0.4})O{sub 2} was investigated to understand the effect of replacement of the cobalt by aluminum on the structural and electrochemical properties. In situ X-ray absorption spectroscopy (XAS) was performed, utilizing a novel in situ electrochemical cell, specifically designed for long-term X-ray experiments. The cell was cycled at a moderate rate through a typical Li-ion battery operating voltage range. (1.0-4.7 V) XAS measurements were performed at different states of charge (SOC) during cycling, at the Ni, Co, and the Mn edges, revealing details about the response of the cathode to Li insertion and extraction processes. The extended X-ray absorption fine structure (EXAFS) region of the spectra revealed the changes of bond distance and coordination number of Ni, Co, and Mn absorbers as a function of the SOC of the material. The oxidation states of the transition metals in the system are Ni{sup 2+}, Co{sup 3+}, and Mn{sup 4+} in the as-made material (fully discharged), while during charging the Ni{sup 2+} is oxidized to Ni{sup 4+} through an intermediate stage of Ni{sup 3+}, Co{sup 3+} is oxidized toward Co{sup 4+}, and Mn was found to be electrochemically inactive and remained as Mn{sup 4+}. The EXAFS results during cycling show that the Ni-O changes the most, followed by Co-O, and Mn-O varies the least. These measurements on this cathode material confirmed that the material retains its symmetry and good structural short-range order leading to the superior cycling reported earlier.

  19. Microscopical characterization of carbon materials derived from coal and petroleum and their interaction phenomena in making steel electrodes, anodes and cathode blocks for the Microscopy of Carbon Materials Working Group of the ICCP

    Science.gov (United States)

    Predeanu, G.; Panaitescu, C.; Bălănescu, M.; Bieg, G.; Borrego, A.G.; Diez, M. A.; Hackley, Paul C.; Kwiecińska, B.; Marques, M.; Mastalerz, Maria; Misz-Kennan, M.; Pusz, S.; Suarez-Ruiz, I.; Rodrigues, S.; Singh, A. K.; Varma, A. K.; Zdravkov, A.; Zivotić, D.

    2015-01-01

    This paper describes the evaluation of petrographic textures representing the structural organization of the organic matter derived from coal and petroleum and their interaction phenomena in the making of steel electrodes, anodes and cathode blocks.This work represents the results of the Microscopy of Carbon Materials Working Group in Commission III of the International Committee for Coal and Organic Petrology between the years 2009 and 2013. The round robin exercises were run on photomicrograph samples. For textural characterization of carbon materials the existing ASTM classification system for metallurgical coke was applied.These round robin exercises involved 15 active participants from 12 laboratories who were asked to assess the coal and petroleum based carbons and to identify the morphological differences, as optical texture (isotropic/anisotropic), optical type (punctiform, mosaic, fibre, ribbon, domain), and size. Four sets of digital black and white microphotographs comprising 151 photos containing 372 fields of different types of organic matter were examined. Based on the unique ability of carbon to form a wide range of textures, the results showed an increased number of carbon occurrences which have crucial role in the chosen industrial applications.The statistical method used to evaluate the results was based on the “raw agreement indices”. It gave a new and original view on the analysts' opinion by not only counting the correct answers, but also all of the knowledge and experience of the participants. Comparative analyses of the average values of the level of overall agreement performed by each analyst in the exercises during 2009–2013 showed a great homogeneity in the results, the mean value being 90.36%, with a minimum value of 83% and a maximum value of 95%.

  20. Power generation by packed-bed air-cathode microbial fuel cells

    KAUST Repository

    Zhang, Xiaoyuan

    2013-08-01

    Catalysts and catalyst binders are significant portions of the cost of microbial fuel cell (MFC) cathodes. Many materials have been tested as aqueous cathodes, but air-cathodes are needed to avoid energy demands for water aeration. Packed-bed air-cathodes were constructed without expensive binders or diffusion layers using four inexpensive carbon-based materials. Cathodes made from activated carbon produced the largest maximum power density of 676±93mW/m2, followed by semi-coke (376±47mW/m2), graphite (122±14mW/m2) and carbon felt (60±43mW/m2). Increasing the mass of activated carbon and semi-coke from 5 to ≥15g significantly reduced power generation because of a reduction in oxygen transfer due to a thicker water layer in the cathode (~3 or ~6cm). These results indicate that a thin packed layer of activated carbon or semi-coke can be used to make inexpensive air-cathodes for MFCs. © 2013 Elsevier Ltd.

  1. Bicontinuous Structure of Li₃V₂(PO₄)₃ Clustered via Carbon Nanofiber as High-Performance Cathode Material of Li-Ion Batteries.

    Science.gov (United States)

    Chen, Lin; Yan, Bo; Xu, Jing; Wang, Chunguang; Chao, Yimin; Jiang, Xuefan; Yang, Gang

    2015-07-01

    In this work, the composite structure of Li3V2(PO4)3 (LVP) nanoparticles with carbon nanofibers (CNF) is designed. The size and location of LVP particles, and the degree of graphitization and diameter of carbon nanofibers, are optimized by electrospinning and heat treatment. The bicontinuous morphologies of LVP/CNF are dependent on the carbonization of PVP and simultaneous growing of LVP, with the fibers shrunk and the LVP crystals grown toward the outside. LVP nanocystals clustered via carbon nanofibers guarantee improving the diffusion ability of Li(+), and the carbon fiber simultaneously guarantees the effective electron conductivity. Compared with the simple carbon-coated LVP and pure LVP, the particle-clustered structure guarantees high rate capability and long-life cycling stability of NF-LVP as cathode for LIBs. At 20 C rate in the range 3.0-4.3 V, NF-LVP delivers the initial capacity of 122.6 mAh g(-1) close to the theoretical value of 133 mAh g(-1), and maintains 97% of the initial capacity at the 1000th cycle. The bead-like structure of cathode material clustered via carbon nanofibers via electrospinning will be further applied to high-performance LIBs.

  2. Controlled solvothermal synthesis and electrochemical performance of LiCoPO4 submicron single crystals as a cathode material for lithium ion batteries

    Science.gov (United States)

    Wu, Borong; Xu, Hongliang; Mu, Daobin; Shi, Lili; Jiang, Bing; Gai, Liang; Wang, Lei; Liu, Qi; Ben, Liubin; Wu, Feng

    2016-02-01

    The submicron single crystals of LiCoPO4 with 500 nm diameter are prepared by solvothermal method. The carbon coated sample is obtained using sucrose as carbon source under 650 °C subsequently. It is investigated that the solvent composition has an effect on the morphology and the electrochemical performance of the cathode material. The as-prepared samples are characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopic, dynamic light scattering, and Fourier transform infrared spectra. The electrochemical performance is evaluated by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The LiCoPO4/C cathode can reach an initial discharge capacity of 123.8 mA h g-1 at 0.1C, with a retention of 83% after 100 cycles. A discharge capacity of 84.9 mA h g-1 is still attainable when the rate is up to 2C. The good cycling performance and rate capability are contributed to the decrease of particle size along with the lower antisite defect concentration in the LCP crystals, and uniform carbon coating.

  3. Voigt-wave propagation in active materials

    CERN Document Server

    Mackay, Tom G

    2015-01-01

    If a dissipative anisotropic dielectric material, characterized by the permittivity matrix $\\underline{\\underline{\\epsilon}}$, supports Voigt-wave propagation, then so too does the analogous active material characterized by the permittivity matrix $\\underline{\\underline{{\\tilde{\\epsilon}}}}$, where $\\underline{\\underline{{\\tilde{\\epsilon}}}}$ is the hermitian conjugate of $\\underline{\\underline{\\epsilon}}$. Consequently, a dissipative material that supports Voigt-wave propagation can give rise to a material that supports the propagation of Voigt waves with attendant linear gain in amplitude with propagation distance, by infiltration with an active dye.

  4. Highly Active and Durable Co-Doped Pt/CCC Cathode Catalyst for Polymer Electrolyte Membrane Fuel Cells

    International Nuclear Information System (INIS)

    Highlights: •Co-doped Pt core–shell type catalyst having 0.75 nm thick Pt shell is synthesized. •Co-doped Pt exhibited mass activity of 0.44 A mgPt−1 at 0.9 ViR-free. •Co-doped Pt cathode catalyst showed high stability under cycling conditions. •Co-doped Pt catalyst showed only 16% power density loss after 30,000 cycles. •The enhanced stability is due to the increase in onset potential for PtO2 formation. -- Abstract: Cathode catalyst based on Co-doped Pt deposited on carbon composite catalyst (CCC) support with high measured activity and stability under potential cycling conditions for polymer electrolyte membrane (PEM) fuel cells was developed in this study. The catalyst was synthesized through platinum deposition on Co-doped CCC support containing pyridinic-nitrogen active sites followed by controlled heat-treatment. High resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) studies confirmed uniform Pt deposition (Pt/CCC catalyst, dPt = 2 nm) and formation of Co-doped Pt/CCC catalyst (dPt = 5.4 nm) respectively. X-ray energy dispersive spectrometry (XEDS) line-scan studies showed the formation of Co-core Pt-shell type catalyst with a Pt-shell thickness of ∼0.75 nm. At 0.9 ViR-free, the Co-doped Pt/CCC catalyst showed initial mass activity of 0.44 A mgPt−1 and 0.25 A mgPt−1 after 30,000 potential cycles between 0.6 and 1.0 V corresponding to an overall measured activity loss of 42.8%. The commercial Pt-Co/C showed initial mass activity of 0.38 A mgPt−1 and ∼70% loss of activity after 30,000 cycles. The enhanced catalytic activity at high potentials and stability of mass activity for the Co-doped Pt/CCC catalyst are attributed to the formation of compressive Pt lattice catalyst due to Co doping. The Co-doped Pt/CCC showed stable open circuit potential close to 1.0 V under H2-air with an initial power density of 857 mW cm−2 and only 16% loss after 30,000 cycles. Catalyst durability studies performed between 0

  5. Effect of thermal treatment on the properties of electrospun LiFePO4–carbon nanofiber composite cathode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Graphical abstract: The composites prepared with the thermal treatment process of stabilization at 280 °C for 4 h with a heating rate of 2 °C min−1 in air followed by carbonization at 800 °C for 14 h with a heating rate of 2 °C min−1 in argon exhibit the optimal electrochemical properties. - Highlights: • Binder-free LiFePO4–CNF composite cathode materials are prepared. • The conductive carbon and LiFePO4 formation take place simultaneously during thermal treatment. • The reaction behavior of the LiFePO4 precursors during thermal treatment are investigated. • Different thermal treatment processes would generate different electrochemical performance. • Cycling performance and rate capability are improved with a suitable thermal treatment condition. - Abstract: Binder-free LiFePO4–carbon nanofiber (LiFePO4–CNF) composites as lithium-ion battery cathode materials are fabricated by electrospinning and subsequent thermal treatments. The thermal decomposition behavior of the electrospun LiFePO4 precursor–polyacrylonitrile (LiFePO4 precursor–PAN) nanofiber composites and the reaction of the LiFePO4 precursors during thermal treatment are investigated. The effects of thermal treatment parameters such as heating rate, temperature, and duration for stabilization and carbonization on the microstructure, morphology, carbon content, crystal structure of the composites, and electrochemical performance of the resultant half-cell are also studied. When the electrospun LiFePO4 precursor–PAN nanofiber composites are first stabilized in air at 280 °C for 4 h with a heating rate of 2 °C min−1 and then carbonized in argon at 800 °C for 14 h with a heating rate of 2 °C min−1, the obtained LiFePO4–CNF composites exhibit optimal electrochemical properties in terms of a higher initial discharge capacity, more stable charge–discharge cycle behavior, and better rate performance. The initial discharge capacity of the composites is 146.3 mA h g−1 at

  6. Effects of cathode materials on discharge characteristics of Li-B alloy/FeS2 thermal battery

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The effects of FeS2 on the discharge characteristics of Li-B alloy/FeS2 thermal battery had been studied. Results showed that 2.5 % (mass fraction)Li2O would be needed to rule out the voltage pulse in the first part of discharge curves for the FeS2 powder of small particle size ( < 44μm). After thermal decomposition, the FeS2 had transformed to Fe(1-x)S where x = 0. 024~ 0. 066. The deficiency of the cathode FeS2 would make discharge voltage decrease 0.4 V. In the discharge test at high temperature (600 ℃ ), the discharge voltage decreased fast with the acceleration of the thermal decomposition of FeS2.

  7. Bifunctional quaternary ammonium compounds to inhibit biofilm growth and enhance performance for activated carbon air-cathode in microbial fuel cells

    Science.gov (United States)

    Li, Nan; Liu, Yinan; An, Jingkun; Feng, Cuijuan; Wang, Xin

    2014-12-01

    The slow diffusion of hydroxyl out of the catalyst layer as well as the biofouling on the surface of cathode are two problems affecting power for membrane-less air-cathode microbial fuel cells (MFCs). In order to solve both of them simultaneously, here we simply modify activated carbon air-cathode using a bifunctional quaternary ammonium compound (QAC) by forced evaporation. The maximum power density reaches 1041 ± 12 mW m-2 in an unbuffered medium (0.5 g L-1 NaCl), which is 17% higher than the control, probably due to the accelerated anion transport in the catalyst layer. After 2 months, the protein content reduced by a factor of 26 and the power density increases by 33%, indicating that the QAC modification can effectively inhibit the growth of cathodic biofilm and improve the stability of performance. The addition of NaOH and QAC epoxy have a negative effect on power production due to the clogging of pores in catalyst layer.

  8. Voigt-wave propagation in active materials

    OpenAIRE

    Mackay, Tom G.; Lakhtakia, Akhlesh

    2015-01-01

    If a dissipative anisotropic dielectric material, characterized by the permittivity matrix $\\underline{\\underline{\\epsilon}}$, supports Voigt-wave propagation, then so too does the analogous active material characterized by the permittivity matrix $\\underline{\\underline{{\\tilde{\\epsilon}}}}$, where $\\underline{\\underline{{\\tilde{\\epsilon}}}}$ is the hermitian conjugate of $\\underline{\\underline{\\epsilon}}$. Consequently, a dissipative material that supports Voigt-wave propagation can give ris...

  9. Improved 4-chlorophenol dechlorination at biocathode in bioelectrochemical system using optimized modular cathode design with composite stainless steel and carbon-based materials.

    Science.gov (United States)

    Kong, Fanying; Wang, Aijie; Ren, Hong-Yu

    2014-08-01

    This study developed and optimized a modular biocathode materials design in bioelectrochemical system (BES) using composite metal and carbon-based materials. The 4-chlorophenol (4-CP) dechlorination could be improved with such composite materials. Results showed that stainless steel basket (SSB) filled with graphite granules (GG) and carbon brush (CB) (SSB/GG/CB) was optimum for dechlorination, followed by SSB/CB and SSB/GG, with rate constant k of 0.0418 ± 0.0002, 0.0374 ± 0.0004, and 0.0239 ± 0.0002 h(-1), respectively. Electrochemical impedance spectroscopy (EIS) demonstrated that the composite materials with metal can benefit the electron transfer and decrease the charge transfer resistance to be 80.4 Ω in BES-SSB/GG/CB, much lower than that in BES-SSB (1674.3 Ω), BES-GG (387.3 Ω), and BES-CB (193.8 Ω). This modular cathode design would be scalable with successive modules for BES scale-up, and may offer useful information to guide the selection and design of BES materials towards dechlorination improvement in wastewater treatment. PMID:24926596

  10. DARHT 2 kA Cathode Development

    Energy Technology Data Exchange (ETDEWEB)

    Henestroza, E.; Houck, T.; Kwan, J.W.; Leitner, M.; Miram, G.; Prichard, B.; Roy, P.K.; Waldron, W.; Westenskow, G.; Yu, S.; Bieniosek, F.M.

    2009-03-09

    In the campaign to achieve 2 kA of electron beam current, we have made several changes to the DARHT-II injector during 2006-2007. These changes resulted in a significant increase in the beam current, achieving the 2 kA milestone. Until recently (before 2007), the maximum beam current that was produced from the 6.5-inch diameter (612M) cathode was about 1300 A when the cathode was operating at a maximum temperature of 1140 C. At this temperature level, the heat loss was dominated by radiation which is proportional to temperature to the fourth power. The maximum operating temperature was limited by the damage threshold of the potted filament and the capacity of the filament heater power supply, as well as the shortening of the cathode life time. There were also signs of overheating at other components in the cathode assembly. Thus it was clear that our approach to increase beam current could not be simply trying to run at a higher temperature and the preferred way was to operate with a cathode that has a lower work function. The dispenser cathode initially used was the type 612M made by SpectraMat. According to the manufacturer's bulletin, this cathode should be able to produce more than 10 A/cm{sup 2} of current density (corresponding to 2 kA of total beam current) at our operating conditions. Instead the measured emission (space charge limited) was 6 A/cm{sup 2}. The result was similar even after we had revised the activation and handling procedures to adhere more closely to the recommend steps (taking longer time and nonstop to do the out-gassing). Vacuum was a major concern in considering the cathode's performance. Although the vacuum gauges at the injector vessel indicated 10{sup -8} Torr, the actual vacuum condition near the cathode in the central region of the vessel, where there might be significant out-gassing from the heater region, was never determined. Poor vacuum at the surface of the cathode degraded the emission (by raising the work function

  11. DARHT 2 kA Cathode Development

    International Nuclear Information System (INIS)

    In the campaign to achieve 2 kA of electron beam current, we have made several changes to the DARHT-II injector during 2006-2007. These changes resulted in a significant increase in the beam current, achieving the 2 kA milestone. Until recently (before 2007), the maximum beam current that was produced from the 6.5-inch diameter (612M) cathode was about 1300 A when the cathode was operating at a maximum temperature of 1140 C. At this temperature level, the heat loss was dominated by radiation which is proportional to temperature to the fourth power. The maximum operating temperature was limited by the damage threshold of the potted filament and the capacity of the filament heater power supply, as well as the shortening of the cathode life time. There were also signs of overheating at other components in the cathode assembly. Thus it was clear that our approach to increase beam current could not be simply trying to run at a higher temperature and the preferred way was to operate with a cathode that has a lower work function. The dispenser cathode initially used was the type 612M made by SpectraMat. According to the manufacturer's bulletin, this cathode should be able to produce more than 10 A/cm2 of current density (corresponding to 2 kA of total beam current) at our operating conditions. Instead the measured emission (space charge limited) was 6 A/cm2. The result was similar even after we had revised the activation and handling procedures to adhere more closely to the recommend steps (taking longer time and nonstop to do the out-gassing). Vacuum was a major concern in considering the cathode's performance. Although the vacuum gauges at the injector vessel indicated 10-8 Torr, the actual vacuum condition near the cathode in the central region of the vessel, where there might be significant out-gassing from the heater region, was never determined. Poor vacuum at the surface of the cathode degraded the emission (by raising the work function value). We reexamined all

  12. Effect of conductive additives in LiFePO4 cathode for lithium-ion batteries

    OpenAIRE

    Shim, J; Guerfi, A.; Zaghib, K.; Striebel, K.A.

    2003-01-01

    The electrochemical properties of LiFePO4 cathodes with different carbon contents were studied to find out the role of carbon as conductive additive. LiFePO4 cathodes containing from 0 percent to 12 percent of conductive additive (carbon black or mixture of carbon black and graphite) were cycled at different C rates. The capacity of LiFePO4 cathode increased, as conductive additive content increased. Carbon increased the utilization of active material and the electrical conductivity of e...

  13. Preparation and Electrochemical Properties of Coral-like Li2FeSiO4/C Cathode Material by Two-Step Precipitation Method

    Science.gov (United States)

    Yan, Yinglin; Ren, Bing; Xu, Yunhua; Wang, Juan; Yang, Rong; Zhong, Lisheng; Zhao, Nana; Wu, Hong

    2016-06-01

    Lithium iron silicate (Li2FeSiO4) cathode materials have been synthesized by a soft chemical method combined with spray drying, being both simple and economical. Super P, as a new kind of nanoscale carbon black, was added in the synthesis process. The phase and microstructure of the samples were characterized by x-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy. The results show that the obtained Li2FeSiO4 possessed coral-like morphology with size range from 250 nm to 450 nm. Super P was decorated on the surface of the Li2FeSiO4 particles. Furthermore, the electrochemical properties of the products were tested, indicating that the as-obtained Li2FeSiO4/C composite presented high specific discharge capacities and stable cycling performance, which can be attributed to the coral-like morphology and Super P coating.

  14. 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.

  15. Research progress in cathode materials for lithium-air battery%锂空气电池正极材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    娄永兵; 刘艳; 朱林

    2012-01-01

    综述了目前国内外锂空气电池研究领域的进展,尤其是正极材料的研究进展;分析了目前研究的局限和问题的集中所在,如过电位、循环稳定性和安全性等;展望了锂空气电池的发展方向及应用趋势.%The progress in lithium-air battery research was reviewed,specifically the progress in cathode materials. The current research limitations and existing problems were discussed,such as over potential, cycle stability and safety, the development direction and application trend were forecasted.

  16. High rate performance of LiFePO4 cathode materials co-doped with C and Ti4+ by microwave synthesis

    Indian Academy of Sciences (India)

    Yan Cui; Miao Wang; Ruisong Guo

    2009-12-01

    Nanostructured LiFePO4 powder with a narrow particle size (ca. 100 nm) for high rate lithium-ion battery cathode application was obtained by microwave heating and using citric acid as carbon source. The microstructures and morphologies of the synthesized materials were investigated by X-ray diffraction and scanning electron microscope while the electrochemical performances were evaluated by galvanostatic charge–discharge. The carbon coating and Ti4+ could improve the conductivity both between the LiFePO4 particles and the intrinsic electronic conductivity. The LiFePO4 doped with 5% C and 1% Ti4+ resulted in a specific capacity of 114.95 mAh.g-1 and 102.4 mAh.g-1 at discharge rates of 0.3C and 1C, respectively, and the cycle performance is very good.

  17. Synthesis and characterization of LiMgyMn2–yO4 cathode materials by a modified Pechini process for lithium batteries

    Indian Academy of Sciences (India)

    A Subramania; N Angayarkanni; A R Sathiya Priya; R Gangadharan; T Vasudevan

    2005-12-01

    Cubic spinels of composition, LiMgyMn2–yO4, with = 0.0, 0.05, 0.1, 0.15 and 0.2, were synthesized by a modified Pechini process using polyethylene glycol and citric acid. The phase formation and/or crystallization of the precursors were studied by thermal analysis. Products were characterized by X-ray diffraction and SEM analysis. Coin cells were fabricated with lithium as the anode and LiMgyMn2–yO4 as the cathode in an electrolyte of 1 M LiPF6 in a 1 : 1 (v/v) mixture of EC and DEC. The charge–discharge studies were performed and the results were compared with materials prepared by a solid state thermal method.

  18. Preparation and Electrochemical Properties of Coral-like Li2FeSiO4/C Cathode Material by Two-Step Precipitation Method

    Science.gov (United States)

    Yan, Yinglin; Ren, Bing; Xu, Yunhua; Wang, Juan; Yang, Rong; Zhong, Lisheng; Zhao, Nana; Wu, Hong

    2016-10-01

    Lithium iron silicate (Li2FeSiO4) cathode materials have been synthesized by a soft chemical method combined with spray drying, being both simple and economical. Super P, as a new kind of nanoscale carbon black, was added in the synthesis process. The phase and microstructure of the samples were characterized by x-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy. The results show that the obtained Li2FeSiO4 possessed coral-like morphology with size range from 250 nm to 450 nm. Super P was decorated on the surface of the Li2FeSiO4 particles. Furthermore, the electrochemical properties of the products were tested, indicating that the as-obtained Li2FeSiO4/C composite presented high specific discharge capacities and stable cycling performance, which can be attributed to the coral-like morphology and Super P coating.

  19. Key strategies for enhancing the cycling stability and rate capacity of LiNi0.5Mn1.5O4 as high-voltage cathode materials for high power lithium-ion batteries

    Science.gov (United States)

    Yi, Ting-Feng; Mei, Jie; Zhu, Yan-Rong

    2016-06-01

    Spinel LiNi0.5Mn1.5O4 (LNMO) is one of the most promising high voltage cathode materials for future application due to its advantages of large reversible capacity, high thermal stability, low cost, environmental friendliness, and high energy density. LNMO can provide 20% and 30% higher energy density than traditional cathode materials LiCoO2 and LiFePO4, respectively. Unfortunately, LNMO-based batteries with LiPF6-based carbonate electrolytes always suffer from severe capacity deterioration and poor thermostability because of the oxidization of organic carbonate solvents and decomposition of LiPF6, especially at elevated temperatures and water-containing environment. Hence, it is necessary to systematically and comprehensively summarize the progress in understanding and modifying LNMO cathode from various aspects. In this review, the structure, transport properties and different reported possible fading mechanisms of LNMO cathode are first discussed detailedly. And then, the major goal of this review is to highlight new progress in using proposed strategies to improve the cycling stability and rate capacity of LNMO-based batteries, including synthesis, control of special morphologies, element doping and surface coating etc., especially at elevated temperatures. Finally, an insight into the future research and further development of LNMO cathode is discussed.

  20. High-performance cathode elements for gas-discharge light sources

    Directory of Open Access Journals (Sweden)

    Sevastyanov V. V.

    2009-02-01

    Full Text Available Application of cathode elements of the arc-discharge activator made on the basis of developed material — alloy of iridium and rare-earth metals (of cerium group — has been suggested. The working samples of arc lamps have been produced and tested. The location of metal-alloy cathode has been optimized. The tests demonstrated, that after 4500 hours of work the lighting-up and glowing parameters of such lamps remained stable.

  1. A three-dimensional LiFePO{sub 4}/carbon nanotubes/graphene composite as a cathode material for lithium-ion batteries with superior high-rate performance

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Xingling [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006 (China); Zhang, Haiyan, E-mail: hyzhang@gdut.edu.cn [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006 (China); Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, Guangzhou 510006 (China); Chen, Yiming, E-mail: chenym@gdut.edu.cn [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006 (China); Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, Guangzhou 510006 (China); Wang, Wenguang [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006 (China); Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, Guangzhou 510006 (China); Ye, Yipeng; Zheng, Chuchun; Deng, Peng [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006 (China); Shi, Zhicong [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006 (China); Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, Guangzhou 510006 (China)

    2015-03-25

    Graphical abstract: The excellent electrochemical performances can be attributed to the synergistic effect of CNTs and graphene. - Highlights: • The LFP–CNT–G composite was successfully prepared by solid station method. • The interlaced CNTs reduced the crumple of graphene and improved tap density of the composite. • The LFP–CNT–G electrode exhibited superior electrochemical performance. - Abstract: A three-dimensional lithium iron phosphate (LiFePO{sub 4})/carbon nanotubes (CNTs)/graphene composite was successfully synthesized via solid-state reaction. The LiFePO{sub 4}/carbon nanotubes/graphene (LFP–CNT–G) composite used as Li-ions battery cathode material exhibits superior high-rate capability and favorable charge–discharge cycle performance under relative high current density compared with that of LiFePO{sub 4}/carbon nanotubes (LFP–CNT) composite and LiFePO{sub 4}/graphene (LFP–G) composite. Graphene nanosheets and CNTs construct 3D conducting networks are favor for faster electron transfer, higher Li-ions diffusion coefficient and lower resistance during the Li-ions reversible reaction. The synergistic effect of graphene nanosheets and CNTs improves the rate capability and cycling stability of LiFePO{sub 4}-based cathodes. The LFP–CNT–G electrode shows reversible capacity of 168.9 mA h g{sup −1} at 0.2 C and 115.8 mA h g{sup −1} at 20 C. The electrochemical impedance spectroscopy demonstrate that the LFP–CNT–G electrode has the smallest charge-transfer resistance, indicating that the fast electron transfer from the electrolyte to the LFP–CNT–G active materials in the Li-ions intercalation/deintercalation reactions owing to the three-dimensional networks of graphene and carbon nanotubes.

  2. Nano-sized LiFePO4/C composite with core-shell structure as cathode material for lithium ion battery

    International Nuclear Information System (INIS)

    Graphical abstract: Nano-sized LiFePO4/C composite with core-shell structure was fabricated via a well-designed approach as cathode material forlithium ion battery. The nano-sized LiFePO4/C composite with whole carbon shell coating layer showed an excellent electrical performance. - Abstract: Nano-sized composite with LiFePO4-core and carbon-shell was synthesized via a facile route followed by heat treatment at 650 °C. X-ray diffraction (XRD) shows that the core is well crystallized LiFePO4. The electron microscopy (SEM and TEM) observations show that the core-shell structured LiFePO4/C composite coating with whole carbon shell layer of ∼2.8 nm, possesses a specific surface area of 51 m2 g−1. As cathode material for lithium ion battery, the core-shell LiFePO4/C composite exhibits high initial capacity of 161 mAh g−1 at 0.1 C, excellent high-rate discharge capacity of 135 mAh g−1 at 5 C and perfect cycling retention of 99.6% at 100th cycle. All these promising results should be contributed to the core-shell nanostructure which prevents collapse of the particle structure in the long-term charge and discharge cycles, as well as the large surface area of the nano-sized LiFePO4/C composite which enhances the electronic conductivity and shortens the distance of lithium ion diffusion

  3. Nonactivated and Activated Biochar Derived from Bananas as Alternative Cathode Catalyst in Microbial Fuel Cells

    OpenAIRE

    Haoran Yuan; Lifang Deng; Yujie Qi; Noriyuki Kobayashi; Jiahuan Tang

    2014-01-01

    Nonactivated and activated biochars have been successfully prepared by bananas at different thermotreatment temperatures. The activated biochar generated at 900°C (Biochar-act900) exhibited improved oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performances in alkaline media, in terms of the onset potential and generated current density. Rotating disk electron result shows that the average of 2.65 electrons per oxygen molecule was transferred during ORR of Biochar-act900...

  4. LiFe1−xMIIxPO4/C (MII = Co, Ni, Mg) as cathode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Highlights: • LiFe1−xMIIxPO4/C (MII = Co, Ni, Mg) cathode materials for LIBs were studied. • LiFePO4 doping results in the charge/discharge rate increase. • LiFe0.9Ni0.1PO4 retains 62 mAh/g capacity at discharge current 3000 mA/g. • MII ion ordering takes place in LiFe1−xMIIxPO4/C (MII = Co, Ni) materials. - Abstract: LiFe1−xMIIxPO4/C (MII = Co, Ni, Mg) composites had been obtained by sol–gel method. Structure and morphology of the obtained materials have been studied with the use of the XRD-analysis, SEM and Mössbauer spectroscopy. Their electrochemical behavior has been investigated with the use of charge/discharge tests. The materials doped by cobalt and nickel were shown to be characterized by an increased lithium intercalation and deintercalation rates, and retain a high capacity during charge and discharge the battery at high currents densities (LiFe0.9Ni0.1PO4 capacity amounts to 145 and 62 mAh/g at a discharge current 50 and 3000 mA/g). Mg2+ incorporation into LiFePO4/C cathode material results in the slight increase of charge/discharge rate and significant capacity decrease. Mössbauer spectroscopy has shown that MII ions in the LiFe1−xMIIxPO4/C (MII = Co, Ni) materials are orderly distributed both in charged and discharged states, each iron ion has no more than one MII ion in the nearest environment. In the case of Ni-doped samples the ordering is less pronounced. The reasons of the changes observed in the electrochemical performances and charge/discharge rate have been discussed on the base of Mössbauer spectroscopy and XRD data

  5. Magnetism in olivine-type LiCo(1-x)Fe(x)PO4 cathode materials: bridging theory and experiment.

    Science.gov (United States)

    Singh, Vijay; Gershinsky, Yelena; Kosa, Monica; Dixit, Mudit; Zitoun, David; Major, Dan Thomas

    2015-12-14

    In the current paper, we present a non-aqueous sol-gel synthesis of olivine type LiCo1-xFexPO4 compounds (x = 0.00, 0.25, 0.50, 0.75, 1.00). The magnetic properties of the olivines are measured experimentally and calculated using first-principles theory. Specifically, the electronic and magnetic properties are studied in detail with standard density functional theory (DFT), as well as by including spin-orbit coupling (SOC), which couples the spin to the crystal structure. We find that the Co(2+) ions exhibit strong orbital moment in the pure LiCoPO4 system, which is partially quenched upon substitution of Co(2+) by Fe(2+). Interestingly, we also observe a non-negligible orbital moment on the Fe(2+) ion. We underscore that the inclusion of SOC in the calculations is essential to obtain qualitative agreement with the observed effective magnetic moments. Additionally, Wannier functions were used to understand the experimentally observed rising trend in the Néel temperature, which is directly related to the magnetic exchange interaction paths in the materials. We suggest that out of layer M-O-P-O-M magnetic interactions (J⊥) are present in the studied materials. The current findings shed light on important differences observed in the electrochemistry of the cathode material LiCoPO4 compared to the already mature olivine material LiFePO4. PMID:26548581

  6. Morphological characterization of LiFePO{sub 4}/C composite cathode materials synthesized via a carboxylic acid route

    Energy Technology Data Exchange (ETDEWEB)

    Fey, George Ting-Kuo; Lu, Tung-Lin [Department of Chemical and Materials Engineering, National Central University, Chung-Li 32054 (China)

    2008-04-01

    A new type of LiFePO{sub 4}/C composite surrounded by a web containing both amorphous and crystalline carbon phases was synthesized by incorporating malonic acid as a carbon source using a high temperature solid-state method. SEM, TEM/SAED/EDS and HRTEM were used to analyze surface morphology and confirmed for the first time that crystalline carbon was present in LiFePO{sub 4}/C composites. The composite was effective in enhancing the electrochemical properties such as capacity and rate capability, because its active component consists of nanometer-sized particles containing pores with a wide range of sizes. An EDS elemental map showed that carbon was uniformly distributed on the surface of the composite crystalline particles. TEM/EDS results clearly show a dark region that is LiFePO{sub 4} with a trace of carbon and a gray region that is carbon only. To evaluate the materials' electrochemical properties, galvanostatic cycling and conductivity measurements were performed. The best cell performance was delivered by the material coated with 60 wt.% malonic acid, which delivered first cycle discharge capacity of 149 mAh g{sup -1} at a C/5 rate and sustained 222 cycles at 80% of capacity retention. When carboxylic acid was used as a carbon source to produce LiFePO{sub 4}, overall conductivity increased from 10{sup -5} to 10{sup -4} S cm{sup -1}, since particle growth was prevented during the final sintering process. (author)

  7. Simple cathode design for Li-S batteries : cell performance and mechanistic insights by in operando X-ray diffraction

    OpenAIRE

    Kulisch, Jörn; Sommer, Heino; Brezesinski, Torsten; Janek, Jürgen

    2014-01-01

    Rechargeable batteries have been receiving increasing attention over the past several years, particularly with regard to the accelerated development of electric vehicles, but also for their potential in grid storage applications. Among the broad range of cathode active materials, elemental sulfur has the highest theoretical specific capacity, thereby making it one of the most promising positive electrode materials these days. In the present work, we show that already a simple cathode design (...

  8. Carbon-free bifunctional cathodes for the use in Lithium - Air Batteries with an aqueous alkaline electrolyte

    OpenAIRE

    Wittmaier, Dennis; Wagner, Norbert; Friedrich, K. Andreas

    2014-01-01

    Carbon materials are widely used in gas diffusion electrodes due to their high electronic conductivity, relatively low costs and catalytic activity towards oxygen reduction reaction (ORR), the cathodic reaction during discharging. During charging a lithium-air battery the cathode is operated in oxygen evolution reaction (OER) mode. Carbon materials corrode in OER mode, this leads to degradation and a power loss of the electrode. To improve long-term stability and reduce side reactions as H2 a...

  9. Structural evolution and the capacity fade mechanism upon long-term cycling in Li-rich cathode material.

    Science.gov (United States)

    Song, Bohang; Liu, Zongwen; Lai, Man On; Lu, Li

    2012-10-01

    High capacity Li-rich layered cathode Li(Li(0.2)Mn(0.54)Ni(0.13)Co(0.13))O(2) and doped one are investigated to understand mechanisms of capacity fade as well as voltage decrease upon long-term cycling. Detailed electrochemical analysis reveals a phase-separation-like behavior with increase in the cycle number, which is responsible for gradual reduction in discharge voltage. X-ray photoelectron spectroscopy (XPS), transmission electron microscope coupled with energy dispersive X-ray spectroscopy (TEM-EDS) and inductively coupled plasma emission spectrometry (ICP) analysis results show increase in valence of transition metals on the surface of powder at a fully discharged state in addition to surface dissolution of Ni, leading to rapid capacity loss. High resolution transmission electron microscopy (HR-TEM) shows a phase transformation from original layered structure into spinel-like nano-domains in local structure. Though such an unexpected structural change is unfavorable because of lower output voltage, it is observed to be beneficial for high-rate performance.

  10. High Cycling Performance Cathode Material: Interconnected LiFePO4/Carbon Nanoparticles Fabricated by Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    Zhigao Yang

    2014-01-01

    Full Text Available Interconnected LiFePO4/carbon nanoparticles for Li-ion battery cathode have been fabricated by sol-gel method followed by a carbon coating process involving redox reactions. The carbon layers coated on the LiFePO4 nanoparticles not only served as a protection layer but also supplied fast electrons by building a 3D conductive network. As a cooperation, LiFePO4 nanoparticles encapsulated in interconnected conductive carbon layers provided the electrode reactions with fast lithium ions by offering the lithium ions shortening and unobstructed pathways. Field emission scanning electron microscopy (FESEM and X-ray diffraction (XRD tests showed optimized morphology. Electrochemical characterizations including galvanostatic charge/discharge, cyclic voltammetry (CV, and electrochemical impedance spectroscopy (EIS tests, together with impedance parameters calculated, all indicated better electrochemical performance and excellent cycling performance at high rate (with less than 9.5% discharge capacity loss over 2000 cycles, the coulombic efficiency maintained about 100%.

  11. Synthesis of Li2FeP2O7/Carbon nanocomposite as cathode materials for Li-ion batteries

    Science.gov (United States)

    Nagano, Hiroaki; Taniguchi, Izumi

    2015-12-01

    A Li2FeP2O7/Carbon (C) nanocomposite was successfully synthesized via a combination of spray pyrolysis and wet ball milling followed by annealing from a precursor solution; in which LiNO3, H3PO4 and Fe(NO3)3·9H2O were stoichiometrically dissolved into distilled water. Ascorbic acid was added to the precursor solution as a reduction agent. The peaks of the Li2FeP2O7/C nanocomposite obtained by X-ray diffraction analysis were indexed to the monoclinic structure with the space group P21/c. The Li2FeP2O7/C nanocomposite cathode delivered a first discharge capacity of 100 mAh g-1 at 0.05 C, which corresponded to 91% of its theoretical capacity. After various higher discharge rates from 0.05 to 2 C in the cycle performance test, a discharge capacity of 93 mAh g-1 was achieved at 0.05 C, which showed an excellent capacity retention (93%) after 29 cycles.

  12. Improving the electrochemical properties of Li1.2Mn0.52Co0.08Ni0.2O2 cathode material by uniform surface nanocoating with samarium fluoride through depositional-hydrothermal route

    International Nuclear Information System (INIS)

    Graphical abstract: Li1.2Mn0.52Co0.08Ni0.2O2 cathode material uniformly nanocoated with samarium fluoride (SmF3) has been successfully synthesized through a chemical deposition method followed by low-temperature hydrothermal treatment. The surface modified cathode shows a significantly improved cycling stability and rate capability. - Highlights: • Samarium fluoride is originally used as coating material of Li-rich layered cathode. • Low-temperature hydrothermal treatment is employed to establish uniform surface coating. • Cathode nanocoated with SmF3 shows improved rate capability and cycling stability. • Coating material suppresses the side reaction between electrode and electrolyte. - Abstract: Surface nanocoating of lithium-rich layered Li1.2Mn0.52Co0.08Ni0.2O2 with samarium fluoride (SmF3) has been performed through a chemical deposition route combined with a low-temperature hydrothermal treatment. The surface-modified Li1.2Mn0.52Co0.08Ni0.2O2 particles are uniformly and completely covered by an amorphous SmF3 protective layer with a thin thickness of ∼20 nm. After surface modification, the coated Li1.2Mn0.52Co0.08Ni0.2O2 as cathode shows a significantly improved cycling stability, keeping a capacity retention of 84.5% after 150 cycles at 2 C, much higher than 68.9%forits uncoated counterpart. Moreover, the coated sample delivers an enhanced rate capability with an average capacity of ∼132.3 mA h g−1 when charged at 5 C and discharged at 0.2 C, while the uncoated counterpart only exhibits a capacity of ∼111.4 mA h g−1 under the same conditions. Our results reveal that the remarkably improved electrochemical performance of the surface-modified cathode is attributed to the presence of uniform, robust, and nanoscale SmF3 coating layer, which not only suppresses the growth of SEI layer by reducing the side reaction between cathode and electrolyte solution, but also strengthens the structure stability of the Li-rich layered cathode materials

  13. Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

    Energy Technology Data Exchange (ETDEWEB)

    Dyartanti, Endah Retno; Jumari, Arif, E-mail: arifjumari@yahoo.com; Nur, Adrian; Purwanto, Agus [Research Group of Battery & Advanced Material, Department of Chemical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A Kentingan, Surakarta Indonesia 57126 (Indonesia)

    2016-02-08

    A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO{sub 4}) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO{sub 4} and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, dried and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging.

  14. Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

    International Nuclear Information System (INIS)

    A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO4) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO4 and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, dried and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging

  15. Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

    Science.gov (United States)

    Dyartanti, Endah Retno; Jumari, Arif; Nur, Adrian; Purwanto, Agus

    2016-02-01

    A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO4) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO4 and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, dried and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging.

  16. Improving rate performance of LiFePO{sub 4} cathode materials by hybrid coating of nano-Li{sub 3}PO{sub 4} and carbon

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Shi-Xi, E-mail: zhaosx@sz.tsinghua.edu.cn [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Ding, Hao; Wang, Yan-Chao [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Li, Bao-Hua [Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Nan, Ce-Wen [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2013-07-25

    Highlights: •This paper reports an improved solid-state method which leads to a uniform coating. The influence of Li{sub 3}PO{sub 4} and carbon coating on the electrochemical performance of LiFePO{sub 4} was studied. •LiFePO{sub 4} coating with Li{sub 3}PO{sub 4} and carbon shows a higher capacity than pure carbon coating sample. •Results indicate that the surface structure has an important influence on the electrochemical performance of LiFePO{sub 4}. The addition of Li{sub 3}PO{sub 4} can decrease the interfacial resistance of Li FePO{sub 4}. -- Abstract: Li{sub 3}PO{sub 4} coating on the surface of LiFePO{sub 4} particles was prepared by direct dispersing LiFePO{sub 4} precursor in starch slurry with nano-Li{sub 3}PO{sub 4}. The existence of nano-Li{sub 3}PO{sub 4} was confirmed with X-ray powder diffraction (XRD). And the particle size and morphology were observed by scanning electron microscope (SEM) and transmission electron microscope analysis (TEM). The effects of the mixture coating on rate performance of LiFePO{sub 4} cathode vs Li anode at 25 °C was investigated. Li{sub 3}PO{sub 4} and carbon mixing coated LiFePO{sub 4} cathode materials exhibited markedly improved rate capability relative to bare carbon-coated LiFePO{sub 4}. Analyses on cell impedance showed that the Li{sub 3}PO{sub 4} coating decreased the interfacial impedance. Transmission electron microscope analysis, electrochemical impedance spectroscopy (EIS) and cyclic voltammograms (CV) were carried out to explain the reason of better rate performance by Li{sub 3}PO{sub 4} coating.

  17. Improving rate performance of LiFePO4 cathode materials by hybrid coating of nano-Li3PO4 and carbon

    International Nuclear Information System (INIS)

    Highlights: •This paper reports an improved solid-state method which leads to a uniform coating. The influence of Li3PO4 and carbon coating on the electrochemical performance of LiFePO4 was studied. •LiFePO4 coating with Li3PO4 and carbon shows a higher capacity than pure carbon coating sample. •Results indicate that the surface structure has an important influence on the electrochemical performance of LiFePO4. The addition of Li3PO4 can decrease the interfacial resistance of Li FePO4. -- Abstract: Li3PO4 coating on the surface of LiFePO4 particles was prepared by direct dispersing LiFePO4 precursor in starch slurry with nano-Li3PO4. The existence of nano-Li3PO4 was confirmed with X-ray powder diffraction (XRD). And the particle size and morphology were observed by scanning electron microscope (SEM) and transmission electron microscope analysis (TEM). The effects of the mixture coating on rate performance of LiFePO4 cathode vs Li anode at 25 °C was investigated. Li3PO4 and carbon mixing coated LiFePO4 cathode materials exhibited markedly improved rate capability relative to bare carbon-coated LiFePO4. Analyses on cell impedance showed that the Li3PO4 coating decreased the interfacial impedance. Transmission electron microscope analysis, electrochemical impedance spectroscopy (EIS) and cyclic voltammograms (CV) were carried out to explain the reason of better rate performance by Li3PO4 coating

  18. Effect of Iron-based Impurities on the performance of nanostructured C-LiFePO4 cathode materials for Li ion Batteries

    Science.gov (United States)

    Vaishnava, P.; Dixit, A.; Bazzi, K.; Sahana, M. B.; Sudakar, C.; Nazri, M.; Naik, V.; Garg, V. K.; Oliveira, A. C.; Nazri, G. A.; Naik, R.

    2012-02-01

    We report synthesis of pure and C-LiFePO4 nanoparticles in 20-30 nm size by sol-gel method. Three samples of C-LiFePO4 were prepared by mixing 0.25M, 0.50M, and 1M lauric acid in the precursor solutions for carbon coating the particles. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), IR spectroscopy, SQUID magnetometery, Raman spectroscopy, and Fe^57 M"ossbauer spectroscopy. All the samples were thoroughly investigated for their electrochemical properties. The XRD measurements showed all the samples are single phase materials with no impurity phase. However, we identified at least three residual non crystalline impurity phases simultaneously using Fe^57 M"ossbauer spectroscopy, XPS, and the magnetic measurements. The elemental chemical states for Fe 2p, P 2p, and O 1s are analyzed using XPS for LiFePO4 and compared with those of C-LiFePO4 materials. SQUID magnetometery measurements suggest an antiferromagnetic transition ˜50 K in both pure LiFePO4 and C-LiFePO4 samples. The role of various phases, such as FeP, Fe2P, α-Fe and Fe2O3 identified and analyzed by Fe^57 M"ossbauer spectroscopy and XPS, will be discussed in relationship to the electrochemical properties of the cathode materials.

  19. Ion energy distributions for the identification of active species and processes in low pressure hollow cathode discharges

    Energy Technology Data Exchange (ETDEWEB)

    Tanarro, I; Herrero, V J [Instituto de Estructura de la Materia, CSIC, Serrano 123, 28006 Madrid (Spain)], E-mail: itanarro@iem.cfmac.csic.es

    2009-08-15

    Energy distributions of ions generated in hollow cathode low pressures dc discharges of different gases and gas mixtures containing Ar, H{sub 2}, N{sub 2}, O{sub 2} or CH{sub 4} are studied by quadrupole mass spectrometry. The ions are sampled through a small diaphragm in the grounded cathode. The measured distributions are mostly determined by the acceleration of ions in the sheath region between the negative glow and the cathode, displaying in general a narrow peak centred at energies close to the anode potential, but with specific features for the distinct ions. It is shown that information about ion production and sheath collision processes can be derived from the shapes of the different energy distributions. In some cases these distributions are used for the estimation of the relative abundance of ions with the same mass/charge ratio but different compositions in complex gas mixtures.

  20. A Highly Active and Alcohol-Tolerant Cathode Electrocatalyst Containing Ag Nanoparticles Supported on Graphene

    International Nuclear Information System (INIS)

    A highly active oxygen reduction reaction (ORR) catalyst was synthesized by supporting Ag nano-particles on graphene nano platelets (Ag/GNP) via ultrasound treatment. The Ag/GNP catalyzes the O2 molecule through a 4-electron reduction to water in 0.1 M KOH electrolyte. The half-wave potential for the ORR on Ag/GNP is similar to a Pt black coated electrode (i.e -0.27 V at Ag/GNP, and -0.18 V at 40% Pt/C vs.SCE). The kinetic rate for the ORR on Ag/GNP is 3.16 × 10−2 cm · s−1 at -0.4 V vs. SCE. The effect of alcohols and other impurities on the ORR catalytic activity for Ag/GNP was examined and found to be highly tolerant to methanol, ethanol and ethylene glycol. The Ag/GNP catalyst is also tolerant to tetraalkyl ammonium hydroxides; i.e. functional groups related to the chemical structure of common alkaline electrolyte membranes

  1. Composite Cathodes for Dual-Rate Li-Ion Batteries

    Science.gov (United States)

    Whitacre, Jay; West, William; Bugga, Ratnakumar

    2008-01-01

    Composite-material cathodes that enable Li-ion electrochemical cells and batteries to function at both high energy densities and high discharge rates are undergoing development. Until now, using commercially available cathode materials, it has been possible to construct cells that have either capability for high-rate discharge or capability to store energy at average or high density, but not both capabilities. However, both capabilities are needed in robotic, standby-power, and other applications that involve duty cycles that include long-duration, low-power portions and short-duration, high-power portions. The electrochemically active ingredients of the present developmental composite cathode materials are: carbon-coated LiFePO4, which has a specific charge capacity of about 160 mA h/g and has been used as a high-discharge-rate cathode material and Li[Li(0.17)Mn(0.58)Ni(0.25)]O2, which has a specific charge capacity of about 240 mA h/g and has been used as a high-energy-density cathode material. In preparation for fabricating the composite material cathode described, these electrochemically active ingredients are incorporated into two sub-composites: a mixture comprising 10 weight percent of poly(vinylidine fluoride); 10 weight percent of carbon and 80 weight percent of carbon coated LiFePO4; and, a mixture comprising 10 weight percent of PVDF, and 80 weight percent of Li[Li(0.17)Mn(0.58)Ni(0.25)]O2. In the fabrication process, these mixtures are spray-deposited onto an aluminum current collector. Electrochemical tests performed thus far have shown that better charge/discharge performance is obtained when either 1) each mixture is sprayed on a separate area of the current collector or (2) the mixtures are deposited sequentially (in contradistinction to simultaneously) on the same current-collector area so that the resulting composite cathode material consists of two different sub-composite layers.

  2. Preparation of nanocomposite thoriated tungsten cathode by swaging technique

    Institute of Scientific and Technical Information of China (English)

    王发展; 诸葛飞; 张晖; 丁秉钧

    2002-01-01

    By using the high energy ball milling method,the nanosized ThO2 powders were obtained.Through mixing powders,sintering and hot swaging processing,a nanocomposite thoriated tungsten cathode was fabricated.The relative density of the nanocomposite material is near 100%.The microstructure of nanocomposite cathode is quite different from that of conventional thoriated tungsten cathode.Most of thoria particles are less than 100 nm in diameter,and distribute on the boundaries of tungsten grains.The nanocomposite cathode shows a much lower arc starting field than that of conventional cathode,which will improve the performance of the cathode significantly.

  3. 锂离子电池纳米锂锰氧化物正极材料的研究进展%Research Progress in Nano-scale Lithium Manganese Oxide as Cathode Material for Lithium Ion Batteries

    Institute of Scientific and Technical Information of China (English)

    曾丽珍

    2012-01-01

    综述了近年来锂离子电池正极材料锂锰氧化物的研究现状,重点对锂锰氧化物的结构和性能的关系,尖晶石锂锰氧化物的制备以及其改性研究进行了阐述。%New progress of nanotechnology applied in lithium ion battery of lithium manganese oxide as cathode material was summarized during recent years,focusing on the relationship between structure and properties of lithium manganese oxide,the preparation methods of nanometer lithium manganese oxide materials cathode material and modification of spinel lithium manganese oxide materials were described.

  4. Neutron activation analysis of reference materials

    International Nuclear Information System (INIS)

    The importance is pointed out of neutron activation analysis in the preparation of reference materials, and studies are reported conducted recently by UJV. Instrumental neutron activation analysis has been used in testing homogeneity and in determining 28 elements in newly prepared reference standards of coal fly ash designated ENO, EOP and ECH. For accuracy testing, the same method was used in the analysis of NBS SRM-1633a Trace Elements in Coal Fly Ash and IAEA CRM Soil-5 and RM Soil-7. Radiochemical neutron activation analysis was used in determining Cd, Cu, Mn, Mo, and Zn in biological materials NBS SRM-1577 Bovine Liver, Bowen's Kale and in IAEA RM Milk Powder A-11 and Animal Muscle H-4. In all instances very good precision and accuracy of neutron activation analysis results were shown. (author)

  5. Studies on Bare and Mg-doped LiCoO2 as a cathode material for Lithium ion Batteries

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Layered compounds, Li(MgxCo1-x)O2 (x = 0, 0.03, 0.05) prepared by molten salt method. • They were characterized by XRD, SEM, density and cyclic voltammetry and Galvano static cycling. • Compounds showed reversible capacity values of 147 mAh/g (x = 0), 127 mAh/g (x = 0.03), and 132 mAh/g (x = 0.05), at the end of 60th cycle. - Abstract: In this paper, we report on the preparation of bare and Mg-doped Li(MgxCo1-x)O2 (x = 0, 0.03, 0.05) phases by a molten salt method and their electrochemical properties. They were prepared at 800 °C for 6 h in air. Rietveld refined X-Ray Diffraction data of bare (x = 0) and Mg-doped (x = 0.03, 0.05) compounds show a well-ordered hexagonal layer-type structure (a ∼ 2.81 Å, c ∼ 14.05 Å). Scanning Electron Microscopy (SEM) show hexagonal type morphology at 800 °C. Powder density was close to 5.02 gcm−3, which compares well with the theoretical value. Electrochemical properties were studied in the voltage range of 2.5-4.3 V vs. Li using Cyclic Voltammetry (CV) and galvanostatic cycling. CV studies on bare and Mg-doped LiCoO2 show main cathodic and anodic redox peaks at ∼ 3.9 V and ∼ 4.0 V, respectively. Galvanostatic cycling of Li(MgxCo1-x)O2 (x = 0, 0.03, 0.05) showed reversible capacity values at the 60th cycle to be: 147 (±3) mAh g−1 (x = 0), 127 (±3) mAh g−1 (x = 0.03), and 131 (±3) mAh g−1 (x = 0.05) cycled at a current density of 30 mA g−1. Capacity retention is also favourable at 98.5%

  6. Synthesis and Characteristics of LiNi0.85Co0.15O2 Cathode Materials by Particulate Sol-Gel Method for Lithium Ion Batteries

    Institute of Scientific and Technical Information of China (English)

    ZHU Xian-Jun; CHEN Hong-Hao; ZHAN Hui; LIU Han-Xing; YANG Dai-Ling; ZHOU Yun-Hong

    2005-01-01

    A particulate sol-gel (PSG) method has been successfully used to prepare LiNi0.85Co0.15O2 cathode materials,utilizing the reaction of LiOH·H2O with Ni(CH3COO)2·4H2O and Co(CH3COO)2·4H2O in water-ethanol system.The thermal history of the as-prepared xerogel was established by differential thermal analysis and thermogravimetric analysis. Powder X-ray diffraction confirmed the formation of layered α-NaFeO2 structure at temperature of 700℃ under flowing oxygen. Scanning electron microscope exhibited that the crystalline powder prepared by PSG method had relatively smaller particle size with narrow distribution than the one prepared by solid state reaction.The first discharge capacity of the material by PSG method was 196.4 mAh/g, and the 10th discharge capacity was 189.1 mAh/g at the current density of 18 mA/g between 3.0 and 4.3 V. Its cycling reversibility was observed to be much better than that by solid state reaction, which had 187.3 mAh/g of the first discharge capacity and 167.1mAh/g of the 10th discharge capacity.

  7. A portable x-ray source with a nanostructured Pt-coated silicon field emission cathode for absorption imaging of low-Z materials

    International Nuclear Information System (INIS)

    We report the design, fabrication, and characterization of a portable x-ray generator for imaging of low-atomic number materials such as biological soft tissue. The system uses a self-aligned, gated, Pt-coated silicon field emitter cathode with two arrays of 62 500 nano-sharp tips arranged in a square grid with 10 μm emitter pitch, and a natural convection-cooled reflection anode composed of a Cu bar coated with a thin Mo film. Characterization of the field emitter array demonstrated continuous emission of 1 mA electron current (16 mA cm  −  2) with  >95% current transmission at a 150 V gate-emitter bias voltage for over 20 h with no degradation. The emission of the x-ray source was characterized across a range of anode bias voltages to maximize the fraction of photons from the characteristic K-shell peaks of the Mo film to produce a quasi-monochromatic photon beam, which enables capturing high-contrast images of low-atomic number materials. The x-ray source operating at the optimum anode bias voltage, i.e. 35 kV, was used to image ex vivo and nonorganic samples in x-ray fluoroscopic mode while varying the tube current; the images resolve feature sizes as small as ∼160 µm. (paper)

  8. A portable x-ray source with a nanostructured Pt-coated silicon field emission cathode for absorption imaging of low-Z materials

    Science.gov (United States)

    Basu, Anirban; Swanwick, Michael E.; Fomani, Arash A.; Velásquez-García, Luis Fernando

    2015-06-01

    We report the design, fabrication, and characterization of a portable x-ray generator for imaging of low-atomic number materials such as biological soft tissue. The system uses a self-aligned, gated, Pt-coated silicon field emitter cathode with two arrays of 62 500 nano-sharp tips arranged in a square grid with 10 μm emitter pitch, and a natural convection-cooled reflection anode composed of a Cu bar coated with a thin Mo film. Characterization of the field emitter array demonstrated continuous emission of 1 mA electron current (16 mA cm  -  2) with  >95% current transmission at a 150 V gate-emitter bias voltage for over 20 h with no degradation. The emission of the x-ray source was characterized across a range of anode bias voltages to maximize the fraction of photons from the characteristic K-shell peaks of the Mo film to produce a quasi-monochromatic photon beam, which enables capturing high-contrast images of low-atomic number materials. The x-ray source operating at the optimum anode bias voltage, i.e. 35 kV, was used to image ex vivo and nonorganic samples in x-ray fluoroscopic mode while varying the tube current; the images resolve feature sizes as small as ~160 µm.

  9. Synthesis of spinel LiNi0.5Mn1.5O4 with secondary plate morphology as cathode material for lithium ion batteries

    Science.gov (United States)

    Risthaus, Tim; Wang, Jun; Friesen, Alex; Wilken, Andrea; Berghus, Debbie; Winter, Martin; Li, Jie

    2015-10-01

    Spinel LiNi0.5Mn1.5O4 material has been synthesized by a spray drying process and subsequent solid state reaction. Polyvinylpyrrolidone (PVP) is given as additive to the spray drying precursor solution and its effects on structural and electrochemical properties are evaluated. By using PVP in the synthesis process, the obtained sample displays a secondary plate morphology which is consisting of densely arranged primary octahedrally shaped particles. The new cathode material has a lesser degree of impurity phases, a higher discharge capacity, a superior rate capability, and a slightly better cycling performance than the sample synthesized without PVP. In more detail, by the use of PVP the ratio of Mn3+ to Mn4+ in the final product decreases from 20.8 to 9.2%. The initial discharge capacity at 0.1 C exhibits an increase of about 14%. The normalized capacity at 20 C is 84.1% instead of 67.0%. A slightly improved cycling performance with the capacity retention increase from 93.8 to 97.9% could be observed as well.

  10. Density functional theory study on oxygen adsorption in LaSrCoO 4: An extended cathode material for solid oxide fuel cells

    Science.gov (United States)

    Zhou, Jun; Chen, Gang; Wu, Kai; Cheng, Yonghong; Peng, Bo; Guo, Jiaojiao; Jiang, Yizhe

    2012-01-01

    Solid oxide fuel cell (SOFC) is one of the most promising technologies for a clean and secure source of energy in future due to its high energy efficiency and outstanding fuel flexibility. The search for new materials operating at low-temperature in order to make SOFCs economically competitive is a great challenge facing us today. In this report, atomistic computer simulation based on density functional theory (DFT) has been used to predict the formation of oxygen vacancy and the strong oxygen adsorption kinetics mechanisms in LaSrCoO4. The optimal adsorption configurations as well as the adsorption energies for oxygen molecule adsorption on various sites of LaSrCoO4 (0 1 0) surface were derived. Furthermore, a strong hybridization between Co and O and shorter Co-O bond length for molecular adsorption were obtained by analysis of density of states. The calculated results imply that LaSrCoO4 could serve as possible cathode material due to its low formation and migration energies of oxygen vacancies.

  11. Impact of salinity on cathode catalyst performance in microbial fuel cells (MFCs)

    KAUST Repository

    Wang, Xi

    2011-10-01

    Several alternative cathode catalysts have been proposed for microbial fuel cells (MFCs), but effects of salinity (sodium chloride) on catalyst performance, separate from those of conductivity on internal resistance, have not been previously examined. Three different types of cathode materials were tested here with increasingly saline solutions using single-chamber, air-cathode MFCs. The best MFC performance was obtained using a Co catalyst (cobalt tetramethoxyphenyl porphyrin; CoTMPP), with power increasing by 24 ± 1% to 1062 ± 9 mW/m2 (normalized to the projected cathode surface area) when 250 mM NaCl (final conductivity of 31.3 mS/cm) was added (initial conductivity of 7.5 mS/cm). This power density was 25 ± 1% higher than that achieved with Pt on carbon cloth, and 27 ± 1% more than that produced using an activated carbon/nickel mesh (AC) cathode in the highest salinity solution. Linear sweep voltammetry (LSV) was used to separate changes in performance due to solution conductivity from those produced by reductions in ohmic resistance with the higher conductivity solutions. The potential of the cathode with CoTMPP increased by 17-20 mV in LSVs when the NaCl addition was increased from 0 to 250 mM independent of solution conductivity changes. Increases in current were observed with salinity increases in LSVs for AC, but not for Pt cathodes. Cathodes with CoTMPP had increased catalytic activity at higher salt concentrations in cyclic voltammograms compared to Pt and AC. These results suggest that special consideration should be given to the type of catalyst used with more saline wastewaters. While Pt oxygen reduction activity is reduced, CoTMPP cathode performance will be improved at higher salt concentrations expected for wastewaters containing seawater. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  12. Fabrication and performance of La0.8Sr0.2MnO3/YSZ graded composite cathodes for SOFC

    Institute of Scientific and Technical Information of China (English)

    SUN Kening; PIAO Jinhua; ZHANG Naiqing; CHEN Xinbing; XU Shen; ZHOU Derui

    2008-01-01

    The performance of multi-layer (1-x)La0.8Sr0.2MnO3/xYSZ graded composite cathodes was studied as electrode materials for intermediate solid oxide fuel cells (SOFC). The thermal expansion coefficient, electrical conductivity, and electrochemical performance of multi-layer composite cathodes were investigated. The thermal expansion coefficient and electrical conductivity decreased with the increase in YSZ content. The (1-x)La0.8Sr0.2MnO3/xYSZ composite cathode greatly increased the length of the active triple phase boundary line (TPBL) among electrode, electrolyte, and gas phase, leading to a decrease in polarization resistance and an increase in polarization current density. The polarization current density of the triple-layer graded composite cathode (0.77 A/cm2) was the highest and that of the monolayer cathode (0.13 A/cm2) was the lowest. The polarization resistance (Rp) of the triple-layer graded composite cathode was only 0.182Ω·cm2 and that of the monolayer composite cathode was 0.323Ω·cm2. The power density of the triple-layer graded composite cathode was the highest and that of the monolayer composite cathode was the lowest. The triple-layer graded composite cathode had superior performance.

  13. Lightweight rechargeable storage batteries using polyacetylene, /CH/x as the cathode-active material

    Science.gov (United States)

    Nigrey, P. J.; Macinnes, D., Jr.; Nairns, D. P.; MacDiarmid, A. G.; Heeger, A. J.

    1981-08-01

    It is pointed out that polyacetylene, (CH)x is the first example of a covalent organic polymer which may be chemically doped either p- or n-type to give a series of semiconductors and ultimately 'organic metals'. The electric conductivity can be varied over twelve orders of magnitude depending on the dopant concentration. A number of different dopant ions, solvents, electrolytes, electrolyte concentrations, and battery configurations have been investigated, only one of which is described in order to illustrate the potential application of (CH)x in batteries. The simplest battery configuration shown consists basically of a piece of (CH)x film, nearly all of which was immersed in a propylene carbonate solution of LiClO4. The top of the film was attached to a galvanostat. The negative terminal was attached to a lithium metal electrode immersed in the solution.

  14. Effect of thermal treatment on the properties of electrospun LiFePO{sub 4}–carbon nanofiber composite cathode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Changhuan; Liang, Yinzheng; Yao, Lan; Qiu, Yiping, E-mail: ypqiu@dhu.edu.cn

    2015-04-05

    Graphical abstract: The composites prepared with the thermal treatment process of stabilization at 280 °C for 4 h with a heating rate of 2 °C min{sup −1} in air followed by carbonization at 800 °C for 14 h with a heating rate of 2 °C min{sup −1} in argon exhibit the optimal electrochemical properties. - Highlights: • Binder-free LiFePO{sub 4}–CNF composite cathode materials are prepared. • The conductive carbon and LiFePO{sub 4} formation take place simultaneously during thermal treatment. • The reaction behavior of the LiFePO{sub 4} precursors during thermal treatment are investigated. • Different thermal treatment processes would generate different electrochemical performance. • Cycling performance and rate capability are improved with a suitable thermal treatment condition. - Abstract: Binder-free LiFePO{sub 4}–carbon nanofiber (LiFePO{sub 4}–CNF) composites as lithium-ion battery cathode materials are fabricated by electrospinning and subsequent thermal treatments. The thermal decomposition behavior of the electrospun LiFePO{sub 4} precursor–polyacrylonitrile (LiFePO{sub 4} precursor–PAN) nanofiber composites and the reaction of the LiFePO{sub 4} precursors during thermal treatment are investigated. The effects of thermal treatment parameters such as heating rate, temperature, and duration for stabilization and carbonization on the microstructure, morphology, carbon content, crystal structure of the composites, and electrochemical performance of the resultant half-cell are also studied. When the electrospun LiFePO{sub 4} precursor–PAN nanofiber composites are first stabilized in air at 280 °C for 4 h with a heating rate of 2 °C min{sup −1} and then carbonized in argon at 800 °C for 14 h with a heating rate of 2 °C min{sup −1}, the obtained LiFePO{sub 4}–CNF composites exhibit optimal electrochemical properties in terms of a higher initial discharge capacity, more stable charge–discharge cycle behavior, and better rate

  15. Studies on Synthesis and Electrochemical Performance of Li1+δNi1-xCoxO2-yFy Cathode Materials for Lithium-ion Rechargeable Batteries

    Institute of Scientific and Technical Information of China (English)

    LIU Xing-quan; HE Ze-zhen; LI Shu-hua; LIN Xiao-jing

    2004-01-01

    It is a technological problem of LiNiO2 cathode material for lithium-ion secondary batteries because of the difficult preparation and hard purification, instable performance, remarkable capacity fading at initial discharge, worse thermal stability and safety of Ni-series cathode materials,and it is also the key factor of hindering LiNiO2 cathode material from practical applications.Recently, by doping some metal cations such as Co, Mn, Mg, Al, Cr and so on[1-5] into LiNiO2, the preparation difficulty and the purification hardness can be obviously improved, and the initial irreversible discharge capacity can be reduced, and the ratio of the initial discharge to charge capacity can be enhanced. But the cyclic stability, thermal stability and safety of LiNiO2 are not enough to satisfy the demand of commercial use.At present, the synthesis of LiNiO2 cathode material must be sintered under oxygen atmosphere in most cases, and the improved effect of fluoride doping on the electrochemical properties of LiNiO2 has seldom been reported in the literatures.In this paper, the cobalt cation and fluorine anion co-doping cathode materials Li1+δNi1-xCoxO2-yFy( 0≤δ≤0.2, 0≤x≤0.5, 0≤y≤0.1 ) were synthesized by solid state reaction method at 650℃ ~750℃ under air atmosphere, and characterized by XRD、 SEM、 TEM、 BET、 laser particle-size distribution measurement and electrochemical performance testing, the effect of different nickel sources on the properties of as-synthesized cathode materials was investigated. The results demonstrated that the cobalt and fluorine ions co-doping cathode materials Li1+δNi1-xCoxO2-yFy have complete layered structure, uniform surface morphology and better particle-size distribution as well as excellent electrochemical performances. At 20~25℃, 0.15~0.25mA charge and discharge current,4.25~2.70V cut-off voltage, 0.2~0.5C charge and discharge rate and 0.2~0.5 mA/cm2 current density,LiNi0.8Co0.2O1.95F0.05 cathode material

  16. Evaluation of Al and Some of Its Alloys as Anode Materials vs γ-MnO2 as Cathode Material and Ore Produced γ-MnO2 vs Zn Anode in KOH Solution

    Institute of Scientific and Technical Information of China (English)

    A.M.A.Hashem; Kh.S. Abou-El-Sherbini; S. Zein El Abedin; H. Abbas

    2006-01-01

    In this study electrochemical performance of Al and some of its alloys (Al-Zn, Al-Mg and Al-Mn) anodes vs MnO2 cathode were carried out in alkaline solution. The results show that the Al-Zn alloy anode has the best cell capacity among the other alloys. Cell capacity values go in the order Al-Zn>Al-Mg>Al>Al-Mn. This result is probably related to the nature of passive films formed on the surface of the alloys which examined by scanning electron microscopy (SEM). SEM morphologies of Al and its alloys showed coarse grains of passive films formed on the surface of these anode materials while Al-Mn morphology shows a needle-like structure.Electrolytic manganese dioxide (EMD) produced by electrodepositing on platinum anode from liquor resulting from reduction of low grade pyrolusite ore (β-MnO2) by sulfur slag was characterized as cathode in alkaline Zn-MnO2 batteries. Ore produced sample (EMD1) was performed well in comparison with EMD standard (EMD2) (commercial battery grade electrolytic manganese dioxide, TOSOH-Hellas GH-S). SEM morphology of Zn anode after cell reaction was carried out and showed that Zn anode has fine grains of passive film on its surface.

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

    International Nuclear Information System (INIS)

    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, pO2, 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

  18. Preparation and performance of Nano-LiFePO4/C cathode material for lithium-ion battery

    Science.gov (United States)

    Qin, Xianzhong; Yang, Gai; Ma, Feng; Cai, Feipeng

    2016-01-01

    A high energy density LiFePO4/C material for lithium batteries was synthesized by controlled crystallization-carbothermal reaction, which has been experienced as an effective process for mass production of electrode materials. The structure and morphology of the LiFePO4/C material were characterized by X-ray diffraction and Scanning Electron Microscope (SEM). The electrochemical properties of the synthesized nano-LiFePO4/C were investigated by charge-discharge processing and cyclic voltammetry (CV). The initial discharge capacities of the LiFePO4/C battery were 163.9, 158.4, 154.5, 151.4, and 142 mA h g-1 at 0.1C, 1C, 2C, 5C, and 10C, respectively. The capacity of LiFePO4/C material maintained 98.5% at the rate of 1C after 100 cycles, demonstrating excellent rate capability and cycling performance.

  19. Preparation and characterization of new cathodic materials for Li-ion battery based polypyrrole-FePO4

    International Nuclear Information System (INIS)

    To investigate the electrochemical properties and stability of our samples, we used cyclic voltammetry and electrochemical impedance spectroscopy. We found that PEG-PPy layer on the particles FePO4 considerably increased material conductivity in comparison with a layer of pure PPy. It also improved the incorporation of Li+ ions into FePO4 structure during charging and discharging. (Authors)

  20. Role of Ce and In doping in the performance of LiFePO4 cathode material for Li ion Batteries

    Science.gov (United States)

    Mandal, Balaji; Nazri, Mariam; Vaishnava, Prem P.; Naik, Vaman M.; Nazri, Gholam A.; Naik, Ratna

    2012-02-01

    Recently, the olivine LiFePO4 has attracted attention as a promising cathode material for Li ion batteries. However, its poor electronic conductivity is a major challenge for its industrial applications. Different approaches have been taken to address this problem. Here, we report a method of improving its conductivity by doping In and Ce ions at the Fe site. We prepared the samples by sol-gel method followed by annealing at 650 C in Ar (95%) +H2(5%) atmosphere for 5 hrs. XRD and Raman spectroscopy confirm that the olivine structure remains unchanged upon doping with In and Ce up to 5 wt%. XRD analysis shows the values of the lattice parameters increase with doping as the ionic radii of Ce and In ions are larger than that of the Fe^2+ ion. This observation also suggests that both Ce and In ions replace Fe ions and not the Li ions in the material. Upon doping, ionic conductivity was found to increase from 10-9 to 10-4 Ohm-1cm-1. Interestingly, Ce doped LiFePO4 showed a higher conductivity than In doped LiFePO4. SEM measurements show a bigger grain size of ˜300-500 nm in doped LiFePO4 which decreased to ˜50 nm when the materials were synthesized using 0.25M lauric acid as a precursor. The electrochemical characteristics of the doped LiFePO4 along with conductivity and Raman data will be presented.

  1. Nondestructive gamma activation analysis of mineral materials

    International Nuclear Information System (INIS)

    The basic problems are described related to the use of gamma activation analysis. The applicability was studied of instrumental gamma activation analysis (IGAA) in geology. A number of minerals, rocks, marine sediments and reference materials were studied. For irradiation a betatron and a microtron were used. The results show that IGAA allows the simultaneous determination of a number of trace elements at concentrations of tenths of ppm. The results are given of comparisons made of the analytical possibilities of microtron IGAA and reactor INAA in geology. Tables show the results of the application of IGAA, the main products and parameters of photoexcitation reactions and graphically represented are the gamma spectra of measured materials. (J.B.)

  2. Hydrothermal synthesis of spindle-like Li2FeSiO4-C composite as cathode materials for lithium-ion batteries

    Institute of Scientific and Technical Information of China (English)

    Haiyan Gao; Zhe Hu; Kai Zhang; Fangyi Cheng; Zhanliang Tao; Jun Chen

    2014-01-01

    In this paper, we report on the preparation of Li2FeSiO4, sintered Li2FeSiO4, and Li2FeSiO4-C composite with spindle-like morphologies and their application as cathode materials of lithium-ion batteries. Spindle-like Li2FeSiO4 was synthesized by a facile hydrothermal method with (NH4)2Fe(SO4)2 as the iron source. The spindle-like Li2FeSiO4 was sintered at 600◦C for 6 h in Ar atmosphere. Li2FeSiO4-C composite was obtained by the hydrothermal treatment of spindle-like Li2FeSiO4 in glucose solution at 190◦C for 3 h. Electrochemical measurements show that after carbon coating, the electrode performances such as discharge capacity and high-rate capability are greatly enhanced. In particular, Li2FeSiO4-C with carbon content of 7.21 wt%delivers the discharge capacities of 160.9 mAh·g-1 at room temperature and 213 mAh·g-1 at 45◦C (0.1 C), revealing the potential application in lithium-ion batteries.

  3. One-Pot Hydrothermal Synthesis of LiMn2O4 Cathode Material with Excellent High-Rate and Cycling Properties

    Science.gov (United States)

    Jiang, Qianqian; Wang, Xingyao; Zhang, Han

    2016-08-01

    The spinel LiMn2O4 was prepared by a one-step hydrothermal method using acetone as the reductant under different hydrothermal temperatures. X-ray diffraction and scanning electron microscopy analysis indicated that optimal LiMn2O4 particles (LMO-120) were synthesized at the temperature of 120°C and the particles were well distributed and about 410 nm in size. Electrochemical performance showed that the as-prepared LiMn2O4 particles exhibited a higher initial discharge capacity than commercial LiMn2O4 (131.5 mAh g-1 versus 115.6 mAh g-1 at 0.2 C). An excellent discharge capacity retention rate of 94.07% was observed after 60 charge-discharge cycles. On the other hand, when cycled at the high rate of 1 C, the optimal LiMn2O4 in this work showed a high discharge capacity of 107.5 mAh g-1 in contrast to only 92.3 mAh g-1 of the commercial LiMn2O4. These results indicate that LMO-120 showed excellent electrochemical performance, especially the prolonged cycling life and high-rate performance, which suggested that this spinel LiMn2O4 has promise for practical application as a high-rate cathode material for lithium ion batteries.

  4. Synthesis and characterization of layered Li(Ni1/3Mn1/3Co1/3)O2 cathode materials by spray-drying method

    Institute of Scientific and Technical Information of China (English)

    LIU Zhi-min; HU Guo-rong; PENG Zhong-dong; DENG Xin-rong; LIU Ye-xiang

    2007-01-01

    Spherical Li(Ni1/3Mn1/3Co1/3)O2 was prepared via the homogenous precursors produced by solution spray-drying method. The precursors were sintered at different temperatures between 600 and 1 000 ℃ for 10 h. The impacts of different sintering temperatures on the structure and electrochemical performances of Li(Ni1/3Mn1/3Co1/3)O2 were compared by means of X-ray diffractometry(XRD), scanning electron microscopy(SEM), and charge/discharge test as cathode materials for lithium ion batteries. The experimental results show that the spherical morphology of the spray-dried powers maintains during the subsequent heat treatment and the specific capacity increases with rising sintering temperature. When the sintering temperature rises up to 900 ℃, Li(Ni1/3Mn1/3Co1/3)O2 attains a reversible capacity of 153 mA·h/g between 3.00 and 4.35 V at 0.2C rate with excellent cyclability.

  5. Encapsulation of LiFePO4 by in-situ graphitized carbon cage towards enhanced low temperature performance as cathode materials for lithium ion batteries

    International Nuclear Information System (INIS)

    The severe capacity decay of LiFePO4 at low temperatures (≤0 °C) limits its wide applications as cathode materials for energy storage batteries. Creating comprehensive carbon network between particles with improved electronic conductivity is a well known solution to this problem. Here, a novel structured LiFePO4/C composite was prepared by a facile solid state route, in which nanosized LiFePO4 spheres were encapsulated by in-situ graphitized carbon cages. With the enhancement in electronic conductivity (2.15e−1 S cm−1), the composite presented excellent rate performance at room temperature and remarkable capacity retention at −40 °C, with charge transfer resistance much lower than commercial LiFePO4. - Graphical abstract: A novel structured LiFePO4/C composite was prepared by a facile solid state route, in which nanosized LiFePO4 spheres were encapsulated by in-situ graphitized carbon cages. - Highlights: • Several nano-sized LiFePO4 particles are encapsulated in carbon cage. • Carbon is in-situ graphitized with enhanced electronic conductivity. • The as prepared LiFePO4 exhibits notable capacity retention at −40 °C. • Rct is lowered by a factor of ∼10 compared with commercial LiFePO4

  6. High-rate performance electrospun Na0.44MnO2 nanofibers as cathode material for sodium-ion batteries

    Science.gov (United States)

    Fu, Bi; Zhou, Xuan; Wang, Yaping

    2016-04-01

    Sodium-ion batteries (SIBs) are considered as one of the most promising candidates to replace lithium-ion batteries (LIBs), because of their similar electrochemical properties, and geographical limitations of lithium. However, searching for the appropriate cathode materials for SIBs that can accommodate structure change during the insertion and extraction of sodium ions is facing great challenges due to the relatively larger size of sodium ion. Na0.44MnO2 has recently attracted significant attention because its crystal structure exhibits two types of large channels formed by MnO6 octahedra and MnO5 square pyramids, which facilitate the transportation of sodium ions. However, suffering from the slow kinetics and structural degradation, its rate performance is still not satisfied. Here, we report the fabrication of two types of Na0.44MnO2 hierarchical structures by optimized electrospinning and controlled subsequent annealing process. One is nanofiber (NF) which demonstrates a superior rate performance with reversible specific capacity of 69.5 mAh g-1 at 10 C, attributed to its one-dimensional (1D) ultralong and continuous fibrous network structure; the other is nanorod (NR) which exhibits an excellent cyclic performance with reversible specific capacity of 120 mAh g-1 after 140 cycles, due to its large S-shaped tunnel structure with a single crystalline structure.

  7. Synthesis, characterization and electrochemical performance of Li2FeSiO4/C cathode materials doped by vanadium at Fe/Si sites for lithium ion batteries

    Science.gov (United States)

    Hao, Hao; Wang, Junbo; Liu, Jiali; Huang, Tao; Yu, Aishui

    2012-07-01

    Li2FeSiO4/C composites doped by vanadium at Fe/Si sites have been investigated as cathode materials for lithium ion batteries. Effects of vanadium substitution at different sites on the structure of Li2FeSiO4/C are examined by X-ray diffraction, X-photoelectron spectroscopy and scanning electron microscopy. XPS results show that the oxidation state of vanadium doped at Fe sites is +3, whereas is +5 when doped at Si sites. Electrochemical measurements show that the Li2FeSi0.9V0.1O4/C sample exhibits the best electrochemical performance with initial discharge capacity of 159 mAh g-1 and excellent cyclability with capacity of 145 mAh g-1 at 30th cycle, which can be ascribed to larger cell volume and higher lithium ion diffusion coefficient, however, the initial discharge of the Li2Fe0.9V0.1SiO4/C sample is only 90% of the undoped Li2FeSiO4, which can be attributed to the loss of Fe content.

  8. Graphene-Wrapped Sulfur Particles as a Rechargeable Lithium-Sulfur-Battery Cathode Material with High Capacity and Cycling Stability

    OpenAIRE

    Wang, Hailiang; Yang, Yuan; Liang, Yongye; Robinson, Joshua Tucker; Li, Yanguang; Jackson, Ariel; Cui, Yi; Dai, Hongjie

    2011-01-01

    We report the synthesis of a graphene-sulfur composite material by wrapping polyethyleneglycol (PEG) coated submicron sulfur particles with mildly oxidized graphene oxide sheets decorated by carbon black nanoparticles. The PEG and graphene coating layers are important to accommodating volume expansion of the coated sulfur particles during discharge, trapping soluble polysulfide intermediates and rendering the sulfur particles electrically conducting. The resulting graphene-sulfur composite sh...

  9. Synthesis and enhanced electrochemical performance of the honeycomb TiO2/LiMn2O4 cathode materials

    DEFF Research Database (Denmark)

    Zhang, J.Y.; Shen, J.X.; Wei, C.B.;

    2016-01-01

    angle compare to LiMn2O4, implying that TiO2 doping induced a change of crystal structure. By performing electrochemical measurements, we observed an enhancement of specific capacity (127.28 mAhg−1) and an improvement of cycling stability in the TiO2/LiMn2O4 hybrid materials. After 100 cycles of charge...

  10. Multifunctional semi-interpenetrating polymer network-nanoencapsulated cathode materials for high-performance lithium-ion batteries

    OpenAIRE

    Ju-Myung Kim; Jang-Hoon Park; Chang Kee Lee; Sang-Young Lee

    2014-01-01

    As a promising power source to boost up advent of next-generation ubiquitous era, high-energy density lithium-ion batteries with reliable electrochemical properties are urgently requested. Development of the advanced lithium ion-batteries, however, is staggering with thorny problems of performance deterioration and safety failures. This formidable challenge is highly concerned with electrochemical/thermal instability at electrode material-liquid electrolyte interface, in addition to structura...

  11. The Effect of Counterpart Material on the Sliding Wear of TiAlN Coatings Deposited by Reactive Cathodic Pulverization

    Directory of Open Access Journals (Sweden)

    Michell Felipe Cano Ordoñez

    2015-11-01

    Full Text Available This work aims to study the effect of the counterpart materials (100Cr6, Al2O3 and WC-Co on the tribological properties of TiAlN thin films deposited on AISI H13 steel substrate by reactive magnetron co-sputtering. The structural characterization of the TiAlN films, performed by X-ray diffraction, showed (220 textured fcc crystalline structure. The values of hardness and elastic modulus obtained by nanoindentation were 27 GPa and 420 GPa, respectively, which resulted in films with a relatively high resistance to plastic deformation. Ball-on-disk sliding tests were performed using normal loads of 1 N and 3 N, and 0.10 m/s of tangential velocity. The wear coefficient of the films was determined by measuring the worn area using profilometry every 1000 cycles. The mechanical properties and the chemical stability of the counterpart material, debris formation and the contact stress influences the friction and the wear behavior of the studied tribosystems. Increasing the hardness of the counterpart decreases the coefficient of friction (COF due to lower counterpart material transference and tribofilm formation, which is able to support the contact pressure. High shear stress concentration at the coating/substrate interface was reported for higher load promoting failure of the film-substrate system for all tribopairs

  12. Reactor neutron activation analysis of industrial materials

    International Nuclear Information System (INIS)

    The specific application of neutron activation analysis (n.a.a.) for industrial materials is demonstrated by the determination of impurities in BeO, Al, Si, Cu, Ge, GaP, GaAs, steel, and irradiated uranium. A group scheme gives an orientation about the possibilities of n.a.a. The use of different standards, methods for the measurement of low radioactivities and errors caused by recoil reaction and radiation stimulated diffusion are discussed. (author)

  13. Batteries: Overview of Battery Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Doeff, Marca M

    2010-07-12

    The very high theoretical capacity of lithium (3829 mAh/g) provided a compelling rationale from the 1970's onward for development of rechargeable batteries employing the elemental metal as an anode. The realization that some transition metal compounds undergo reductive lithium intercalation reactions reversibly allowed use of these materials as cathodes in these devices, most notably, TiS{sub 2}. Another intercalation compound, LiCoO{sub 2}, was described shortly thereafter but, because it was produced in the discharged state, was not considered to be of interest by battery companies at the time. Due to difficulties with the rechargeability of lithium and related safety concerns, however, alternative anodes were sought. The graphite intercalation compound (GIC) LiC{sub 6} was considered an attractive candidate but the high reactivity with commonly used electrolytic solutions containing organic solvents was recognized as a significant impediment to its use. The development of electrolytes that allowed the formation of a solid electrolyte interface (SEI) on surfaces of the carbon particles was a breakthrough that enabled commercialization of Li-ion batteries. In 1990, Sony announced the first commercial batteries based on a dual Li ion intercalation system. These devices are assembled in the discharged state, so that it is convenient to employ a prelithiated cathode such as LiCoO{sub 2} with the commonly used graphite anode. After charging, the batteries are ready to power devices. The practical realization of high energy density Li-ion batteries revolutionized the portable electronics industry, as evidenced by the widespread market penetration of mobile phones, laptop computers, digital music players, and other lightweight devices since the early 1990s. In 2009, worldwide sales of Li-ion batteries for these applications alone were US$ 7 billion. Furthermore, their performance characteristics (Figure 1) make them attractive for traction applications such as

  14. Analysis of cathode geometry to minimize cathode erosion in direct current microplasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Causa, Federica [Dipartimento di Scienze dell' Ambiente, della Sicurezza, del Territorio, degli Alimenti e della Salute, Universita degli studi di Messina, 98122 Messina (Italy); Ghezzi, Francesco; Caniello, Roberto; Grosso, Giovanni [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, Via R. Cozzi 53, 20125 Milano (Italy); Dellasega, David [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, Via R. Cozzi 53, 20125 Milano (Italy); Dipartimento di Energia, Politecnico di Milano, Via Ponzio 34/3, 20133 Milano (Italy)

    2012-12-15

    Microplasma jets are now widely used for deposition, etching, and materials processing. The present study focuses on the investigation of the influence of cathode geometry on deposition quality, for microplasma jet deposition systems in low vacuum. The interest here is understanding the influence of hydrogen on sputtering and/or evaporation of the electrodes. Samples obtained with two cathode geometries with tapered and rectangular cross-sections have been investigated experimentally by scanning electron microscopy and energy dispersion X-ray spectroscopy. Samples obtained with a tapered-geometry cathode present heavy contamination, demonstrating cathode erosion, while samples obtained with a rectangular-cross-section cathode are free from contamination. These experimental characteristics were explained by modelling results showing a larger radial component of the electric field at the cathode inner wall of the tapered cathode. As a result, ion acceleration is larger, explaining the observed cathode erosion in this case. Results from the present investigation also show that the ratio of radial to axial field components is larger for the rectangular geometry case, thus, qualitatively explaining the presence of micro-hollow cathode discharge over a wide range of currents observed in this case. In the light of the above findings, the rectangular cathode geometry is considered to be more effective to achieve cleaner deposition.

  15. Enhancing the Thermal and Upper Voltage Performance of Ni-Rich Cathode Material by a Homogeneous and Facile Coating Method: Spray-Drying Coating with Nano-Al2O3.

    Science.gov (United States)

    Du, Ke; Xie, Hongbin; Hu, Guorong; Peng, Zhongdong; Cao, Yanbing; Yu, Fan

    2016-07-13

    The electrochemical performance of Ni-rich cathode material at high temperature (>50 °C) and upper voltage operation (>4.3 V) is a challenge for next-generation lithium-ion batteries (LIBs) because of the rapid capacity degradation over cycling. Here we report improved performance of LiNi0.8Co0.15Al0.05O2 materials via a LiAlO2 coating, which was prepared from a Ni0.80Co0.15Al0.05(OH)2 precursor by spray-drying coating with nano-Al2O3. Investigations by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy revealed that an Al2O3 layer is uniformly distributed on the precursor and a LiAlO2 layer on the as-prepared cathode material. Such a coating shell acts as a scavenger to protect the cathode material from attack by HF and serious side reactions, which remarkably enhances the cycle performance at 55 °C and upper operating voltage (4.4 and 4.5 V). In particular, the sample with a 2% Al2O3 coating shows capacity retentions of 90.40%, 85.14%, 87.85%, and 81.1% after 150 cycles at a rate of 1.0C at room temperature, 55 °C, 4.4 V, and 4.5 V, respectively, which are significantly higher than those of the pristine one. This is mainly due to the significant improvement of the structural stability led by the effective coating technique, which could be extended to other cathode materials to obtain LIBs with enhanced safety and excellent cycling stability. PMID:27328728

  16. Structural integrity--Searching the key factor to suppress the voltage fade of Li-rich layered cathode materials through 3D X-ray imaging and spectroscopy techniques

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yahong; Hu, Enyuan; Yang, Feifei; Corbett, Jeff; Sun, Zhihong; Lyu, Yingchun; Yu, Xiqian; Liu, Yijin; Yang, Xiao-Qing; Li, Hong (BNL); (SLAC); (UCSF); (Donghua); (Chinese Aca. Sci.)

    2016-10-24

    Li-rich layered materials are important cathode compounds used in commercial lithium ion batteries, which, however, suffers from some drawbacks including the so-called voltage fade upon electrochemical cycling. Here, our study employs novel transmission X-ray microscopy to investigate the electrochemical reaction induced morphological and chemical changes in the Li-rich Li2Ru0.5Mn0.5O3 cathode particles at the meso to nano scale. We performed combined X-ray spectroscopy, diffraction and microscopy experiments to systematically study this cathode material's evolution upon cycling as well as to establish a comprehensive understanding of the structural origin of capacity fade through 2D and 3D fine length scale morphology and heterogeneity change of this material. This work suggests that atomic manipulation (e.g. doping, substitution etc.) or nano engineering (e.g. nano-sizing, heterogeneous structure) are important strategies to mitigate the internal strain and defects induced by extensive lithium insertion/extraction. It also shows that maintaining the structural integrity is the key in designing and synthesizing lithium-rich layered materials with better cycle stability.

  17. Sub-2 nm Thick Fluoroalkylsilane Self-Assembled Monolayer-Coated High Voltage Spinel Crystals as Promising Cathode Materials for Lithium Ion Batteries

    Science.gov (United States)

    Zettsu, Nobuyuki; Kida, Satoru; Uchida, Shuhei; Teshima, Katsuya

    2016-08-01

    We demonstrate herein that an ultra-thin fluoroalkylsilane self-assembled monolayer coating can be used as a modifying agent at LiNi0.5Mn1.5O4‑δcathode/electrolyte interfaces in 5V-class lithium-ion batteries. Bare LiNi0.5Mn1.5O4‑δ cathode showed substantial capacity fading, with capacity dropping to 79% of the original capacity after 100 cycles at a rate of 1C, which was entirely due to dissolution of Mn3+ from the spinel lattice via oxidative decomposition of the organic electrolyte. Capacity retention was improved to 97% on coating ultra-thin FAS17-SAM onto the LiNi0.5Mn1.5O4 cathode surface. Such surface protection with highly ordered fluoroalkyl chains insulated the cathode from direct contact with the organic electrolyte and led to increased tolerance to HF.

  18. An O3-type NaNi0.5Mn0.3Ti0.2O2 compound as new cathode material for room-temperature sodium-ion batteries

    Science.gov (United States)

    Wang, Hongbo; Gu, Minyi; Jiang, Jingyu; Lai, Chao; Ai, Xinping

    2016-09-01

    A single phase O3-type layered NaNi0.5Mn0.3Ti0.2O2 compound synthesized via simple solid-state reaction is first reported as a promising cathode material for sodium-ion batteries. A high reversible capacity of approximately 138 mAh g-1 and initial coulombic efficiency of above 96% can be obtained in half-cell. The performance of sodium-ion full-cells with NaNi0.5Mn0.3Ti0.2O2 as the cathode and presodiated hard carbon as the anodes were also evaluated. Based on the mass of cathode, the full-cells can still exhibit a high reversible capacity of ca. 131 mAh g-1. The prominent capacities make NaNi0.5Mn0.3Ti0.2O2 as an important cathode candidate for room temperature sodium-ion batteries.

  19. Research on high density and safety LiCoO2 as cathode materials for lithium ion batteries

    Institute of Scientific and Technical Information of China (English)

    CHEN; Yan-bin; LIU; Ya-fei; BAI; Hou-shan

    2005-01-01

    Three LiCoO2 samples of different specifications were synthesized using different Co3O4 s as starting material, and characterized in physical, electrochemical and safety properties. There demonstrates clear dependence of LiCoO2 on Co3O4 in particle size and density. The main difference among the three LiCoO2 samples lies in physical, rate capability and safety properties, the sample with larger particle size, higher density (accordingly smaller surface area) demonstrates better safety but lower rate capability, while there is little difference among them in terms of capacity and cycling stability despite of the variation in physical properties.

  20. Effect of symbiotic compound Fe{sub 2}P{sub 2}O{sub 7} on electrochemical performance of LiFePO{sub 4}/C cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shuxin, E-mail: liushuxin88@126.com [School of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang, Sichuan 621000 (China); Gu, Chunlei [School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018 (China); Wang, Haibin [School of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang, Sichuan 621000 (China); Liu, Ruijiang [School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Wang, Hong; He, Jichuan [School of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang, Sichuan 621000 (China)

    2015-10-15

    In order to study the effect of symbiotic compound Fe{sub 2}P{sub 2}O{sub 7} on electrochemical performance of LiFePO{sub 4}/C cathode materials, the LiFePO{sub 4}/Fe{sub 2}P{sub 2}O{sub 7}/C cathode materials were synthesized by in-situ synthesis method. The phase compositions and microstructures of the products were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscope (FESEM). Results indicate that the existence of Fe{sub 2}P{sub 2}O{sub 7} does not alter LiFePO{sub 4} crystal structure and the existence of Fe{sub 2}P{sub 2}O{sub 7} decreases the particles size of LiFePO{sub 4}. The electrochemical behavior of cathode materials was analyzed using galvanostatic measurement and cyclic voltammetry (CV). The results show that the existence of Fe{sub 2}P{sub 2}O{sub 7} improves electrochemical performance of LiFePO{sub 4} cathode materials in specific capability and lithium ion diffusion rate. The charge–discharge specific capacity and apparent lithium ion diffusion coefficient increase with Fe{sub 2}P{sub 2}O{sub 7} content and maximizes around the Fe{sub 2}P{sub 2}O{sub 7} content is 5 wt%. It has been had further proved that the Fe{sub 2}P{sub 2}O{sub 7} adding enhances the lithium ion transport to improve the electrochemical performance of LiFePO{sub 4} cathode materials. However, excessive Fe{sub 2}P{sub 2}O{sub 7} will block the electron transfer pathway and affect the electrochemical performances of LiFePO{sub 4} directly. - Graphical abstract: The LiFePO{sub 4}/Fe{sub 2}P{sub 2}O{sub 7}/C cathode materials were synthesized by in-situ synthesis method. The existence of Fe{sub 2}P{sub 2}O{sub 7} does not alter LiFePO{sub 4} crystal structure and the existence of Fe{sub 2}P{sub 2}O{sub 7} decreases the particles size of LiFePO{sub 4}. The charge–discharge specific capacity and apparent lithium ion diffusion coefficient increase with Fe{sub 2}P{sub 2}O{sub 7} content. However, excessive Fe{sub 2}P{sub 2}O{sub 7} will

  1. Progress in application of graphene in Li-ion battery cathode materials%石墨烯在锂离子电池正极材料中应用的进展

    Institute of Scientific and Technical Information of China (English)

    吕璐; 洪建和; 何岗; 何明中

    2012-01-01

    Research progress in graphene composite with cathode materials such as polyanionic,spinel and layered structure to improve the electrochemical performance of Li-ion battery was reviewed. The problems in application of graphene in Li-ion battery cathode materials were summarized.%综述了石墨烯与聚阴离子型、尖晶石型、层状结构的正极材料复合,改善锂离子电池电化学性能的研究进展.总结了石墨烯在锂离子电池正极材料中的应用所面临的问题.

  2. Research on Cathode Materials for Lithium-ion Batteries%锂离子电池正极材料的研究

    Institute of Scientific and Technical Information of China (English)

    喻济兵; 裴波; 侯旭

    2015-01-01

    本文着重介绍了锂离子电池正极材料LiCoO2, LiMn2O4, LiFePO4, LiNi0.5Mn1.5O4, LiNi1/3Co1/3Mn1/3O2(NCM), LiNi0.80Co0.15Al0.05O2(NCA) and xLi2M·n (O13-x)LiMO2的性能、优缺点及改进方法,并对用这些正极材料及锂离子电池在车船用领域的应用作了进一步展望。%The overview of cathode materials for lithium-ion batteries is given. The properties, advantages, disadvantages and modifications of LiCoO2, LiMn2O4, LiFePO4, LiNi0.5Mn1.5O4, LiNi1/3Co1/3Mn1/3O2 (NCM), LiNi0.80Co0.15Al0.05O2 (NCA) and xLi2MnO3· (1-x)LiMO2 are highlighted, the developmental trend of these materials and the application of lithium-ion batteries in car and ship are discussed as well.

  3. Microwave-enhanced electrochemical cycling performance of the LiNi0.2Mn1.8O4 spinel cathode material at elevated temperature.

    Science.gov (United States)

    Raju, Kumar; Nkosi, Funeka P; Viswanathan, Elumalai; Mathe, Mkhulu K; Damodaran, Krishnan; Ozoemena, Kenneth I

    2016-05-14

    The well-established poor electrochemical cycling performance of the LiMn2O4 (LMO) spinel cathode material for lithium-ion batteries at elevated temperature stems from the instability of the Mn(3+) concentration. In this work, a microwave-assisted solid-state reaction has been used to dope LMO with a very low amount of nickel (i.e., LiNi0.2Mn1.8O4, herein abbreviated as LMNO) for lithium-ion batteries from Mn3O4 which is prepared from electrolytic manganese oxide (EMD, γ-MnO2). To establish the impact of microwave irradiation on the electrochemical cycling performance at an elevated temperature (60 °C), the Mn(3+) concentration in the pristine and microwave-treated LMNO samples was independently confirmed by XRD, XPS, (6)LiMAS-NMR and electrochemical studies including electrochemical impedance spectroscopy (EIS). The microwave-treated sample (LMNOmic) allowed for the clear exposure of the {111} facets of the spinel, optimized the Mn(3+) content, promoting structural and cycle stability at elevated temperature. At room temperature, both the pristine (LMNO) and microwave-treated (LMNOmic) samples gave comparable cycling performance (>96% capacity retention and ca. 100% coulombic efficiency after 100 consecutive cycling). However, at an elevated temperature (60 °C), the LMNOmic gave an improved cycling stability (>80% capacity retention and ca. 90% coulombic efficiency after 100 consecutive cycling) compared to the LMNO. For the first time, the impact of microwave irradiation on tuning the average manganese redox state of the spinel material to enhance the cycling performance of the LiNi0.2Mn1.8O4 at elevated temperature and lithium-ion diffusion kinetics has been clearly demonstrated. PMID:27113855

  4. Feature of "Cold" Fusion Reaction in a Deuterated Complex Cathode

    OpenAIRE

    ARATA, Yoshiaki; ZHANG, Yue-Chang

    1992-01-01

    [Abstract] In order to corroborate the evidence of "cold" fusion reaction, a new-type, complex cathode was developed, consisting of a Ni rod with a Pd layer applied by plasma spraying. High reproducibility of a "cold" fusion reaction was confirmed, using a deuterated complex cathode. The Pd layer showed to have activated the surface functions of the deuterated cathode, and a reliable evidence was obtained that a new type of heat generation occurred in the complex cathode.

  5. Comparative study on microstructure of β-Ni(OH)2 as cathode material for Ni-MH battery

    Institute of Scientific and Technical Information of China (English)

    LOU; Yuwan; YANG; Chuanzheng; ZHANG; Xigui; MA; Liping

    2006-01-01

    Microstructures such as micro-strain, crystallite as well as stacking faults can result in broadening of X-ray diffraction lines. Based on least square principle, new computation method and programs, which can separate the two-fold broadening effect caused by crystallite/stacking faults and which can separate the three-fold broadening effect caused by crystallite/residual stress/stacking faults, have been proposed. As a result, micro-strain and crystallite sizes as well as stacking fault probability can be calculated respectively and investigated in detail. Then the microstructures of β-Ni(OH)2 are investigated by means of these methods. The main results are as follows: 1) The shape and size of crystallite as well as stacking fault probability of raw β-Ni(OH)2 are dependent on its preparation technique. 2) Activation changes the microstructure of β-Ni(OH)2. It transforms the crystallite shape from short-fat cylinder into polyhedrons or nearly equiaxial grains.Activation also alters the residual strain states and stacking fault probability. 3) After charge-discharge and cycle-lifetime testing, the crystallites of β-Ni(OH)2 are fined further and its residual strain and fault probability were alternated. The extent of these effects are dependent on circulating conditions. 4) Calcium additive in β-Ni(OH)2 restrains grain fining process and turns twin fault into deformation fault. 5) Comprehensive analysis reveals that micro structural parameters of β-Ni(OH)2 are correlated with some performance of Ni-MH battery.

  6. Atomic layer deposition of NiS and its application as cathode material in dye sensitized solar cell

    International Nuclear Information System (INIS)

    Nickel sulfide (NiS) is grown by atomic layer deposition (ALD) using sequential exposures of bis(2,2,6,6-tetramethylheptane-3,5-dionate)nickel(II) [Ni(thd)2] and hydrogen sulfide (H2S) at 175 °C. Complementary combinations of in situ and ex situ characterization techniques are used to understand the deposition chemistry and the nature of film growth. The saturated growth rate of ca. 0.21 Å per ALD cycle is obtained, which is constant within the ALD temperature window (175–250 °C). As deposited films on glass substrates are found polycrystalline without any preferred orientation. Electrical transport measurement reveals degenerative/semimetallic characteristics with a carrier concentration of ca. 9 × 1022 cm−3 at room temperature. The ALD grown NiS thin film demonstrates high catalytic activity for the reduction of I−/I3− electrolyte that opens its usage as cost-effective counter electrode in dye sensitized solar cells, replacing Pt

  7. Nitrogen-doped porous carbon nanofiber webs/sulfur composites as cathode materials for lithium-sulfur batteries

    International Nuclear Information System (INIS)

    Nitrogen-doped porous carbon nanofiber webs-sulfur composites (N-CNFWs/S) were synthesized for the first time with sulfur (S) encapsulated into nitrogen-doped porous carbon nanofiber webs (N-CNFWs) via a modified oxidative template route, carbonization-activation and thermal treatment. The composites were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), X-ray powder diffraction (XRD), and thermogravimetry (TG) measurements. The results show that sulfur is well dispersed and immobilized homogeneously in the micropores of nitrogen-doped porous carbon nanofiber webs (N-CNFWs) with high electrical conductivity, surface area and large pore volume. The electrochemical tests show that the N-CNFWs/S composites with 60 wt. % of S have a high initial discharge capacity of 1564 mA h g−1, a good cycling stability at the current density of 175 mA g−1, and excellent rate capability (reversible discharging capacity of above 400 mA h g−1 at 1600 mA g−1)

  8. Atomic layer deposition of NiS and its application as cathode material in dye sensitized solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Mahuli, Neha [Center for Research in Nanotechnology and Sciences, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India); Sarkar, Shaibal K., E-mail: shaibal.sarkar@iitb.ac.in [Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India)

    2016-01-15

    Nickel sulfide (NiS) is grown by atomic layer deposition (ALD) using sequential exposures of bis(2,2,6,6-tetramethylheptane-3,5-dionate)nickel(II) [Ni(thd){sub 2}] and hydrogen sulfide (H{sub 2}S) at 175 °C. Complementary combinations of in situ and ex situ characterization techniques are used to understand the deposition chemistry and the nature of film growth. The saturated growth rate of ca. 0.21 Å per ALD cycle is obtained, which is constant within the ALD temperature window (175–250 °C). As deposited films on glass substrates are found polycrystalline without any preferred orientation. Electrical transport measurement reveals degenerative/semimetallic characteristics with a carrier concentration of ca. 9 × 10{sup 22} cm{sup −3} at room temperature. The ALD grown NiS thin film demonstrates high catalytic activity for the reduction of I{sup −}/I{sub 3}{sup −} electrolyte that opens its usage as cost-effective counter electrode in dye sensitized solar cells, replacing Pt.

  9. Lithium difluoro(oxalate)borate and LiBF4 blend salts electrolyte for LiNi0.5Mn1.5O4 cathode material

    Science.gov (United States)

    Zhou, Hongming; Xiao, Kaiwen; Li, Jian

    2016-01-01

    The electrochemical behaviors of lithium difluoro(oxalate)borate (LiODFB) and LiBF4 blend salts in ethylene carbonate + dimethyl carbonate + ethyl(methyl) carbonate (EC + DMC + EMC, 1:1:1, by wt.) have been investigated for LiNi0.5Mn1.5O4 cathode in lithium-ion batteries. The electric conductivity tests are utilized to examine the relationship among solution conductivity, the electrolyte composition and temperature. Through cyclic voltammetry, charge-discharge test and AC impedance measurements, we compare the capacity and cycling efficiency of LNMO cathode in different electrolyte systems at different temperatures and discharge current rates. Scanning electron microscopy (SEM) analysis and X-ray photoelectron spectroscopy (XPS) are served to analyze the surface nature of LNMO cathode after cycles at elevated temperature. These results demonstrate that LNMO cathode can exert excellent electrochemical performance with the increase of LiODFB concentration at room temperature and elevated temperature and it is found that just slight LiBF4, mixed with LiODFB as blend salts, can strikingly improve the cyclability at -20 °C, especially in high-rate cycling. Grouped together, the optimum LiODFB/LiBF4 molar ratio is around 4:1, which can present an excellent affinity to LNMO cathode in a wide electrochemical window.

  10. Li2S@C composite incorporated into 3D reduced graphene oxide as a cathode material for lithium-sulfur batteries

    Science.gov (United States)

    Wang, D. H.; Xie, D.; Yang, T.; Zhong, Y.; Wang, X. L.; Xia, X. H.; Gu, C. D.; Tu, J. P.

    2016-05-01

    Surface conductive engineering on Li2S is critical for construction of advanced cathodes of lithium-sulfur batteries. Herein, we construct a high-performance Li2S-based composite cathode with the help of three-dimensional reduced graphene oxide (3D-rGO) network and outer carbon coating. Typically, the Li2S@C particles are uniformly embedded into 3D-rGO to form a binder-free 3D-rGO-Li2S@C cathode by the combination of a liquid solution-evaporation coating and PVP (Polyvinyl Pyrrolidone) carbonization. The 3D-rGO-Li2S@C cathode exhibits a high initial discharge capacity of 856 mAh g-1 at 0.1C, superior cycling stability with a capacity of 388.4 mAh g-1 after 200 cycles at 1C, corresponding to a low capacity fading rate. It is demonstrated that the outer conductive coating is effective and necessary for electrochemical enhancement of Li2S cathodes by improving electrical conductivity and prohibiting polysulfide from shuttling during cycling.

  11. Effect of MgO nanolayer coated on Li3V2(PO4)3/C cathode material for lithium-ion battery

    International Nuclear Information System (INIS)

    MgO nanolayer coated on Li3V2(PO4)3/C particles was successfully prepared by a sol-gel method. The X-ray diffraction (XRD) shows that the crystal structure of the Li3V2(PO4)3/C cores does not been affected by the coating. Nanolayer-structured MgO on the surface of Li3V2(PO4)3/C particles is demonstrated by high resolution transmission electron microscopy (HRTEM). Galvanostatic charge/discharge, EIS and cyclic voltammetry measurements clearly show that MgO nanocoating stabilizes the structure of the cathode material, decreases the interface charge transfer resistance and enhances the reversibility of electrode reaction. Electrochemical properties of the coated samples were investigated, showing enhancements of the initial discharge capacity, the cyclability and the rate performance. For MgO of 4.5 mol% coated sample, the initial discharge capacity is 194.4 mAh g-1 at 40 mA g-1 current density, which is close to the theoretical discharge capacity of 197 mAh g-1, and the discharge capacity remains 137.5 mAh g-1 after 100 cycles, and its capacity retention of 70.73% is higher than that of pristine Li3V2(PO4)3/C, 43.7%. The initial discharge capacity still reaches 157.81 mAh g-1, 157.29 mAh g-1 and 144.64 mAh g-1 at 1C, 1.5C, 2C rates, respectively.

  12. 层状钴基正极材料的改性研究%Modification of layered Co-based cathode material

    Institute of Scientific and Technical Information of China (English)

    杨占旭; 乔庆东; 任铁强; 李琪

    2012-01-01

    Layered LiCoO2 has been the dominant cathode material for commercial Li-ion batteries because of its ease of production, good rate capability and stable discharge voltage platform. However, layered LiCoO2 shows poor overcharge tolerance and thermal stability, which restrict its commercialization. In this article, the progress in ion substitution and surface treatment of layered LiCoO2 to improve the structural and thermal stability at home and abroad has been described in detail. The mechanism has been discussed as well.%层状LiCoO2是目前商品化的主要正极材料,具有易于制备、较好的倍率性能以及放电电压平稳等优点,但其抗过充电性能和热稳定性差限制了其应用.详细阐述了国内外关于层状LiCoO2正极材料的改性研究进展,包括体相掺杂和表面包覆改性两种方法提高材料的抗过充电性能和热稳定性,并对体相掺杂和表面包覆层状LiCoO2正极材料电化学性能提高的机理进行了讨论.

  13. Growth mechanism and magnetic and electrochemical properties of Na0.44MnO2 nanorods as cathode material for Na-ion batteries

    International Nuclear Information System (INIS)

    Nanorods of Na0.44MnO2 are a promising cathode material for Na-ion batteries due to their large surface area and single crystalline structure. We report the growth mechanism of Na0.44MnO2 nanorods via solid state synthesis and their physical properties. The structure and the morphology of the Na0.44MnO2 nanorods are investigated by X-ray diffraction (XRD), scanning and tunneling electron microscopy (SEM and TEM), and energy-dispersive X-ray (EDX) techniques. The growth mechanism of the rods is investigated and the effects of vapor pressure and partial melting of Na-rich regions are discussed. The magnetic measurements show an antiferromagnetic phase transition at 25 K and the μeff is determined as 3.41 and 3.24 μB from the χ–T curve and theoretical calculation, respectively. The electronic configuration and spin state of Mn3+ and Mn4+ are discussed in detail. The electrochemical properties of the cell fabricated using the nanorods are investigated and the peaks in the voltammogram are attributed to the diffusion of Na ions from different sites. Na intercalation process is explained by one and two Margules and van Laar models. - Highlights: • We synthesized Na0.44MnO2 nanorods via a simple solid state reaction technique. • Our studies show that excess Na plays a crucial role in the nanorod formation. • Magnetization measurements show that Mn3+ ions are in LS and HS states. • The electrochemical properties of the cell fabricated using the nanorods are investigated. • Na intercalation process is explained by one and two Margules and van Laar models

  14. Growth mechanism and magnetic and electrochemical properties of Na{sub 0.44}MnO{sub 2} nanorods as cathode material for Na-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Demirel, S.; Oz, E. [Physic Department, Inonu University, Malatya 44120 (Turkey); Altin, E. [Scientific and Technological Research Center, Inonu University, 44120 (Turkey); Altin, S.; Bayri, A. [Physic Department, Inonu University, Malatya 44120 (Turkey); Kaya, P.; Turan, S. [Department of Materials Science and Engineering, Anadolu University, Eskisehir (Turkey); Avci, S., E-mail: sevdaavci@aku.edu.tr [Department of Materials Science and Engineering, Afyon Kocatepe University, Afyon 3200 (Turkey)

    2015-07-15

    Nanorods of Na{sub 0.44}MnO{sub 2} are a promising cathode material for Na-ion batteries due to their large surface area and single crystalline structure. We report the growth mechanism of Na{sub 0.44}MnO{sub 2} nanorods via solid state synthesis and their physical properties. The structure and the morphology of the Na{sub 0.44}MnO{sub 2} nanorods are investigated by X-ray diffraction (XRD), scanning and tunneling electron microscopy (SEM and TEM), and energy-dispersive X-ray (EDX) techniques. The growth mechanism of the rods is investigated and the effects of vapor pressure and partial melting of Na-rich regions are discussed. The magnetic measurements show an antiferromagnetic phase transition at 25 K and the μ{sub eff} is determined as 3.41 and 3.24 μ{sub B} from the χ–T curve and theoretical calculation, respectively. The electronic configuration and spin state of Mn{sup 3+} and Mn{sup 4+} are discussed in detail. The electrochemical properties of the cell fabricated using the nanorods are investigated and the peaks in the voltammogram are attributed to the diffusion of Na ions from different sites. Na intercalation process is explained by one and two Margules and van Laar models. - Highlights: • We synthesized Na{sub 0.44}MnO{sub 2} nanorods via a simple solid state reaction technique. • Our studies show that excess Na plays a crucial role in the nanorod formation. • Magnetization measurements show that Mn{sup 3+} ions are in LS and HS states. • The electrochemical properties of the cell fabricated using the nanorods are investigated. • Na intercalation process is explained by one and two Margules and van Laar models.

  15. 钠离子电池正极材料的研究进展∗%The research progress of cathode material for sodium-ion batteries

    Institute of Scientific and Technical Information of China (English)

    杨绍斌; 董伟; 沈丁; 王晓亮; 李思南; 王峰; 王阳; 孙闻

    2015-01-01

    钠离子电池与锂离子电池相比,具有钠资源储量丰富、价格低廉等优点,被认为是发展新能源、实现规模化储能极具潜力的二次电池。近年来钠离子电池成为人们研究的热点,相关报道也在逐年增加。综述了钠离子电池正极材料发展中典型化合物,如过渡金属氧化物、聚阴离子化合物等的研究进展,以及目前人们主要采用的纳米化、包覆、掺杂等几种有效的改性手段,并对正极材料未来的研究方向以及发展前景提出了展望。%Compared with lithium-ion batteries,sodium sodium-ion batteries has the resources was abundant, the price was low wait for an advantage,and was considered to be potential secondary battery of development new energy,realizing large-scale energy storage.Sodium-ion batteries in recent years become the research hot spot,the relevant report also increased year by year.This paper reviews development of the typical compounds in sodium-ion battery cathode material,such as transition metal oxides,polyanionic compounds;and the effec-tive modification methods adopting by people such as nano-technology,coating,cladding,etc.Then,the re-search direction and prospects for development of sodium-ion batteries are forecasted.

  16. Electrochemical properties of La0.8Sr0.2FeO3-δbased composite cathode for intermediate temperature SOFC

    Institute of Scientific and Technical Information of China (English)

    ZHANG Naiqing; SUN Kening; JIA Dechang; ZHOU Derui

    2006-01-01

    La0.8Sr0.2FeO3-δ is a new kind of cathode material for intermediate SOFC, but its electrochemical activity is relative poor for the lanthanum gallate based solid oxide fuel cell. In this paper, a novel composite cathode of La0.8Sr0.2FeO3-δ/La0.9 Sr0.1Ga0.8Mg0.2O3-δ was prepared on the LSGM electrolyte substrate by screen-printing method. The results of cathodic polarization measurements show that the overpotential decreases significantly when the composite cathode is used instead of the La0.8Sr0.2FeO3-δ single layer cathode. The cathodic overpotential of the composite La0.8Sr0.2FeO3-δ/La0.9Sr0.1Ga0.8 Mg0.2O3-δ cathode is 150 mV at the current density of 0.2 A·m-2 at 800 ℃, while the cathodic overpotential of the La0.8 Sr0.2 FeO3-δ single layer cathode is higher thaN260 mV at the same condition. The electrochemical impedance spectroscopy was employed to investigate the polarization resistance of the cathode. The polarization resistance of the composite cathode is 1.20 Ω·m2 in open circuit condition, while the value of the single La0.8 Sr0.2 FeO3-δ cathode is 1.235 Ω·m2.

  17. Investigation of Cathode Electrocatalytic Activity using Surface Engineered Thin Film Samples and High Temperature Physical Property Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Salvador, Paul [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2014-02-23

    In this Final Technical Report, a summary of the technical output from the award DE-NT0004105 is given. First, the major goals and observations from the project are reviewed and then specific example results are presented as highlights. The surprising importance of microstructure on the surface chemical exchange coefficient in La0.7Sr0.3MnO3 (LSM) was uncovered in this work and is re-emphasized in this report. Significant orientation and thickness dependencies of the surface exchange coefficient are correlated with microstructural effects, especially to the nature of the strain, dislocation content, and grain boundary population. We also illustrate similar microstructural effects are present in other SOFC cathode systems, including LSCF (La1-xSrxCo1-yFeyO3) and La2NiO4 (LNO). Throughout the report, the relation to SOFC cathode performance is discussed.

  18. Electrochemical evaluation of LiAl{sub 0.05}Ni{sub 0.05}Mn{sub 1.9}O{sub 4} cathode material synthesized via electrospinning method

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xianan; Zhou, Hongwei [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); Department of Physical Chemistry, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); Liu, Guicheng [Beijing Institute of Nanoenergy and Nanosystem, Chinese Academy Sciences, 30 College Road, Beijing 100083 (China); Yin, Zhuang; Jiang, Ying; Wang, Xindong [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); Department of Physical Chemistry, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China)

    2015-05-25

    Highlights: • Dual-doped LiMn{sub 2}O{sub 4} nanofiber cathode is synthesized by electrospinning. • Nanofiber cathode forms porous “network-like” structures. • Al/Ni dual-dope markedly improved the cycle stability and rate performance. - Abstract: One-dimensional LiAl{sub 0.05}Ni{sub 0.05}Mn{sub 1.9}O{sub 4} nanofibers are prepared by an electrospinning method followed by calcination process to investigate the influences of Al/Ni dual-doping on the structural and electrochemical properties of as-prepared cathode materials for Li-ion batteries. X-ray diffraction (XRD) and scanning electron microscope (SEM) characterization results indicate that the as-prepared material have good crystallinity and uniform morphology. Galvanostatic charge–discharge tests demonstrate LiAl{sub 0.05}Ni{sub 0.05}Mn{sub 1.9}O{sub 4} has an improved cyclic performance at 25 °C and high temperature (55 °C), which originates from the enhanced stability by decreasing lattice constant and suppression of Jahn–Teller effect revealed by XPS analysis. Moreover, From the EIS analysis, it is revealed reduced charge transfer resistance of LiAl{sub 0.05}Ni{sub 0.05}Mn{sub 1.9}O{sub 4} compared with those of undoped LiMn{sub 2}O{sub 4}.

  19. Bibliographic data base for low activation materials

    Energy Technology Data Exchange (ETDEWEB)

    Alenina, M.V.; Kolotov, V.P. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow (Russian Federation); Ivanov, L.I. [A.A. Baikov Institute of Metallurgy and Science of Materials, Russian Academy of Sciences, Moscow (Russian Federation)

    2007-07-01

    Full text of publication follows: The analysis of the publications dealing with development of low-activation materials for fusion technology demonstrates that the period of information doubling is about 5-6 years. Such high rate usually is characteristic of the actively developing field of science. To develop an useful instrument for analysis and systematization of the available data a computer based bibliographic system has been developed some time ago. Recently the engine of the system has been significantly modernized. The bibliographic system is based on using of MS SQL server data base which includes main bibliographic information including abstracts. The most important feature of the system is that full-text abstracts searching capabilities are appended with indexing of information by experts to increase its definition. The experts indexes cover the following topics: - Main problems; - Software and methods for calculation; - Libraries of nuclear data; - Spectrum of neutrons for different construction parts of fusion reactor; - Low activation materials; - Technology of production; - Radiation effects; - Utilization of radiation waste; - Estimation of risks; - Designs of fusion reactor; - Nuclear transmutations; - Equipment used for investigations. The primary data base is filling/appending by periodical queries to different bibliographic data bases (INIS, COMPEMDEX and others) via suitable Internet providers including strict analysis of the income information to remove a possible 'information noise' and following data indexing by experts. The data base contains references since 1976 year (when first works in this area have been fulfilled) and until now. The bibliographic system is accessible by means of Internet using different forms developed for queries (http://www.geokhi.ru/{approx}lam{sub d}b). (authors)

  20. Plasma distribution of cathodic ARC deposition system

    Energy Technology Data Exchange (ETDEWEB)

    Anders, S.; Raoux, S.; Krishnan, K.; MacGill, R.A.; Brown, I.G. [Lawrence Berkeley National Lab., CA (United States)

    1996-08-01

    The plasma distribution using a cathodic arc plasma source with and without magnetic macroparticle filter has been determined by depositing on a transparent plastic substrate and measuring the film absorption. It was found that the width of the distribution depends on the arc current, and it also depends on the cathode material which leads to a spatial separation of the elements when an alloy cathode is used. By applying a magnetic multicusp field near the exit of the magnetic filter, it was possible to modify the plasma distribution and obtain a flat plasma profile with a constant and homogeneous elemental distribution.

  1. 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.

  2. Emission current control system for multiple hollow cathode devices

    Science.gov (United States)

    Beattie, John R. (Inventor); Hancock, Donald J. (Inventor)

    1988-01-01

    An emission current control system for balancing the individual emission currents from an array of hollow cathodes has current sensors for determining the current drawn by each cathode from a power supply. Each current sensor has an output signal which has a magnitude proportional to the current. The current sensor output signals are averaged, the average value so obtained being applied to a respective controller for controlling the flow of an ion source material through each cathode. Also applied to each controller are the respective sensor output signals for each cathode and a common reference signal. The flow of source material through each hollow cathode is thereby made proportional to the current drawn by that cathode, the average current drawn by all of the cathodes, and the reference signal. Thus, the emission current of each cathode is controlled such that each is made substantially equal to the emission current of each of the other cathodes. When utilized as a component of a multiple hollow cathode ion propulsion motor, the emission current control system of the invention provides for balancing the thrust of the motor about the thrust axis and also for preventing premature failure of a hollow cathode source due to operation above a maximum rated emission current.

  3. Promoting the bio-cathode formation of a constructed wetland-microbial fuel cell by using powder activated carbon modified alum sludge in anode chamber

    Science.gov (United States)

    Xu, Lei; Zhao, Yaqian; Doherty, Liam; Hu, Yuansheng; Hao, Xiaodi

    2016-01-01

    MFC centered hybrid technologies have attracted attention during the last few years due to their compatibility and dual advantages of energy recovery and wastewater treatment. In this study, a MFC was integrated into a dewatered alum sludge (DAS)- based vertical upflow constructed wetland (CW). Powder activate carbon (PAC) was used in the anode area in varied percentage with DAS to explore its influences on the performance of the CW-MFC system. The trial has demonstrated that the inclusion of PAC improved the removal efficiencies of COD, TN and RP. More significantly, increasing the proportion of PAC from 2% to 10% can significantly enhance the maximum power densities from 36.58 mW/m2 to 87.79 mW/m2. The induced favorable environment for bio-cathode formation might be the main reason for this improvement since the content of total extracellular polymeric substances (TEPS) of the substrate in the cathode area almost doubled (from 44.59 μg/g wet sludge to 87.70 μg/g wet sludge) as the percentage of PAC increased to 10%. This work provides another potential usage of PAC in CW-MFCs with a higher wastewater treatment efficiency and energy recovery. PMID:27197845

  4. Promoting the bio-cathode formation of a constructed wetland-microbial fuel cell by using powder activated carbon modified alum sludge in anode chamber

    Science.gov (United States)

    Xu, Lei; Zhao, Yaqian; Doherty, Liam; Hu, Yuansheng; Hao, Xiaodi

    2016-05-01

    MFC centered hybrid technologies have attracted attention during the last few years due to their compatibility and dual advantages of energy recovery and wastewater treatment. In this study, a MFC was integrated into a dewatered alum sludge (DAS)- based vertical upflow constructed wetland (CW). Powder activate carbon (PAC) was used in the anode area in varied percentage with DAS to explore its influences on the performance of the CW-MFC system. The trial has demonstrated that the inclusion of PAC improved the removal efficiencies of COD, TN and RP. More significantly, increasing the proportion of PAC from 2% to 10% can significantly enhance the maximum power densities from 36.58 mW/m2 to 87.79 mW/m2. The induced favorable environment for bio-cathode formation might be the main reason for this improvement since the content of total extracellular polymeric substances (TEPS) of the substrate in the cathode area almost doubled (from 44.59 μg/g wet sludge to 87.70 μg/g wet sludge) as the percentage of PAC increased to 10%. This work provides another potential usage of PAC in CW-MFCs with a higher wastewater treatment efficiency and energy recovery.

  5. Performance of cobalt-free double-perovskite NdBaFe{sub 2−x}Mn{sub x}O{sub 5+δ} cathode materials for proton-conducting IT-SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Xinbo; Yu, Tian; Ma, Guilin, E-mail: 32uumagl@suda.edu.cn

    2015-07-15

    Highlights: • A novel series of double-perovskite NdBaFe{sub 2−x}Mn{sub x}O{sub 5+δ} cathode materials were prepared. • Among the materials, the NBFM10 exhibits the highest conductivity of 114 S cm{sup −1}. • P-type electronic conduction is dominant in the oxygen partial pressure range tested. • Peak power density of the cell using NBFM10–BZCY composite cathode reached 453 mW cm{sup −2}. • The interfacial polarization resistance (R{sub p}) is as low as 0.06 Ω cm{sup 2} at 700 °C. - Abstract: A novel series of cobalt-free cathode materials, NdBaFe{sub 2−x}Mn{sub x}O{sub 5+δ} (0.0 x 0.3), are prepared by a citric acid–nitrate process. X-ray diffraction (XRD) analysis indicates that all the samples are double-perovskite phases with cubic structure. The conductivity dependence of the cathode materials on temperature (300–800 °C) and oxygen partial pressure (1–10{sup −10} atm) is investigated. Among the tested samples, NdBaFe{sub 1.9}Mn{sub 0.1}O{sub 5+δ} (NBFM10) exhibits the highest conductivity of 114 S cm{sup −1} in air at 550 °C. The H{sub 2}/air fuel cell with the NBFM10–BZCY composite cathode and NiO–BZCY composite anode as well as BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3−α} (BZCY) electrolyte membrane (ca. 30 μm thickness) was assembled and tested at 500–700 °C. The peak power density of the cell reaches 453 mW cm{sup −2}, and the interfacial polarization resistance R{sub p} is only 0.06 Ω cm{sup 2} under open circuit conditions, at 700 °C.

  6. Functionally Graded Cathodes for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Harry Abernathy; Meilin Liu

    2006-12-31

    One primary suspected cause of long-term performance degradation of solid oxide fuels (SOFCs) is the accumulation of chromium (Cr) species at or near the cathode/electrolyte interface due to reactive Cr molecules originating from Cr-containing components (such as the interconnect) in fuel cell stacks. To date, considerable efforts have been devoted to the characterization of cathodes exposed to Cr sources; however, little progress has been made because a detailed understanding of the chemistry and electrochemistry relevant to the Cr-poisoning processes is still lacking. This project applied multiple characterization methods - including various Raman spectroscopic techniques and various electrochemical performance measurement techniques - to elucidate and quantify the effect of Cr-related electrochemical degradation at the cathode/electrolyte interface. Using Raman microspectroscopy the identity and location of Cr contaminants (SrCrO{sub 4}, (Mn/Cr){sub 3}O{sub 4} spinel) have been observed in situ on an LSM cathode. These Cr contaminants were shown to form chemically (in the absence of current flowing through the cell) at temperatures as low as 625 C. While SrCrO{sub 4} and (Mn/Cr){sub 3}O{sub 4} spinel must preferentially form on LSM, since the LSM supplies the Sr and Mn cations necessary for these compounds, LSM was also shown to be an active site for the deposition of Ag{sub 2}CrO{sub 4} for samples that also contained silver. In contrast, Pt and YSZ do not appear to be active for formation of Cr-containing phases. The work presented here supports the theory that Cr contamination is predominantly chemically-driven and that in order to minimize the effect, cathode materials should be chosen that are free of cations/elements that could preferentially react with chromium, including silver, strontium, and manganese.

  7. Sub-2 nm Thick Fluoroalkylsilane Self-Assembled Monolayer-Coated High Voltage Spinel Crystals as Promising Cathode Materials for Lithium Ion Batteries

    Science.gov (United States)

    Zettsu, Nobuyuki; Kida, Satoru; Uchida, Shuhei; Teshima, Katsuya

    2016-01-01

    We demonstrate herein that an ultra-thin fluoroalkylsilane self-assembled monolayer coating can be used as a modifying agent at LiNi0.5Mn1.5O4−δcathode/electrolyte interfaces in 5V-class lithium-ion batteries. Bare LiNi0.5Mn1.5O4−δ cathode showed substantial capacity fading, with capacity dropping to 79% of the original capacity after 100 cycles at a rate of 1C, which was entirely due to dissolution of Mn3+ from the spinel lattice via oxidative decomposition of the organic electrolyte. Capacity retention was improved to 97% on coating ultra-thin FAS17-SAM onto the LiNi0.5Mn1.5O4 cathode surface. Such surface protection with highly ordered fluoroalkyl chains insulated the cathode from direct contact with the organic electrolyte and led to increased tolerance to HF. PMID:27553901

  8. Nd-nickelate solid oxide fuel cell cathode sensitivity to Cr and Si contamination

    Science.gov (United States)

    Andreas Schuler, J.; Lübbe, Henning; Hessler-Wyser, Aïcha; Van herle, Jan

    2012-09-01

    The stability of Nd-nickelate, considered as an alternative solid oxide fuel cell (SOFC) cathode material, was evaluated in this work on its tolerance towards contaminants. Symmetrical cells with Nd1.95NiO4+δ (NNO) electrodes sintered on gadolinia-doped ceria electrolyte supports were monitored over time-spans of 1000 h at 700 °C under polarization in an air-flux with deliberate chromium contamination. Impedance spectroscopy pointed out a polarization increase with time by the growth of the low frequency arc describing the electrode's oxygen reduction and incorporation processes. Post-test observations revealed polluted cathode regions with increasing amounts of Cr accumulations towards the electrolyte/cathode interface. Cr deposits were evidenced to surround active nickelate grain surfaces forming Nd-containing Cr oxides. In addition to exogenous Cr contamination, endogenous contamination was revealed. Silicon, present as impurity material in the raw NNO powder (introduced by milling during powder processing), reacts during sintering steps to form Nd-silicate phases, which decreases the active cathode surface. Nd-depletion of the nickelate, as a result of secondary phase formation with the contaminants Cr and Si (NdCrO4 and Nd4Si3O12), then triggers the thermally-induced decomposition of NNO into stoichiometric Nd2NiO4+δ and NiO. Summarized, the alternative Nd-nickelate cathode also suffers from degradation caused by pollutant species, like standard perovskites.

  9. Monoclinic sulfur cathode utilizing carbon for high-performance lithium-sulfur batteries

    Science.gov (United States)

    Jung, Sung Chul; Han, Young-Kyu

    2016-09-01

    Sulfur cathodes for lithium-sulfur batteries have been designed to be combined with conductive carbon because the insulating nature of sulfur causes low active material utilization and poor rate capability. This paper is the first to report that carbon can induce a phase transition in a sulfur cathode. The stable form of a sulfur crystal at ambient temperature is orthorhombic sulfur. We found that monoclinic sulfur becomes more stable than orthorhombic sulfur if carbon atoms penetrate into the sulfur at elevated temperatures and the carbon density exceeds a threshold of C0.3S8. The high stability of the carbon-containing monoclinic sulfur persists during lithiation and is attributed to locally formed linear SC3S chains with marked stability. This study provides a novel perspective on the role of carbon in the sulfur cathode and suggests control of the crystal phase of electrodes by composite elements as a new way of designing efficient electrode materials.

  10. Cathodic Protection Model Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Performs Navy design and engineering of ship and submarine impressed current cathodic protection (ICCP) systems for underwater hull corrosion control and...

  11. Research Progress in Olivine-type LiFePO4 Cathode Material%橄榄石结构LiFePO4正极材料的最新进展

    Institute of Scientific and Technical Information of China (English)

    宋之林; 乔庆东; 李琪; 杨占旭; 朱崇秀

    2013-01-01

      橄榄石型LiFePO4正极材料具有环境污染小,安全性能好,价格低廉,循环寿命长,工作电压稳定等突出优点,是极具开发和应用潜力的新一代锂离子电池正极材料,尤其是在对材料要求较高的动力电源领域的应用,受到各界的广泛关注。但是其本身的低电子电导率和离子扩散系数,导致材料大倍率性能差,限制了它的大规模应用。因此,对橄榄石结构LiFePO4正极材料的改性成为研究的热点。从三个方面介绍了LiFePO4正极材料的最新研究成果,并对其今后的发展进行展望。%The olivine-type LiFePO4 cathode material has become a new generation of cathode material which is considered as the extremely potential of development and application for using in lithium ion batteries because of its less pollution to the environment, good safety performance and low price, long cycle life and stable operating voltage. So it has been widely concerned, especially in the application of the power batteries that demand higher for the material. But its own low electronic conductivity and ion diffusion coefficient lead to poor large rate performance of the material, which limits its large-scale application. Hence, research on the modification of olivine-type LiFePO4 cathode materials is still a hot spot. In this paper, the latest research results of LiFePO4 cathode materials were introduced from three aspects, and its future development trend was also discussed.

  12. LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES

    Energy Technology Data Exchange (ETDEWEB)

    Harlan U. Anderson; Fatih Dogan; Vladimir Petrovsky

    2002-03-31

    This project has three main goals: Thin Films Studies, Preparation of Graded Porous Substrates and Basic Electrical Characterization and testing of Planar Single Cells. This period has continued to address the problem of making dense 1/2 to 5 {micro}m thick dense layers on porous substrates (the cathode LSM). Our current status is that we are making structures of 2-5 cm{sup 2} in area, which consist of either dense YSZ or CGO infiltrated into a 2-5 {micro}m thick 50% porous layer made of either nanoncrystalline CGO or YSZ powder. This composite structure coats a macroporous cathode or anode; which serves as the structural element of the bi-layer structure. These structures are being tested as SOFC elements. A number of structures have been evaluated both as symmetrical and as button cell configuration. Results of this testing indicates that the cathodes contribute the most to cell losses for temperatures below 750 C. In this investigation different cathode materials were studied using impedance spectroscopy of symmetric cells and IV characteristics of anode supported fuel cells. Cathode materials studied included La{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (LSCF), La{sub 0.7}Sr{sub 0.2}MnO{sub 3} (LSM), Pr{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}O{sub 3} (PSCF), Sm{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (SSCF), and Yb{sub .8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (SSCF). A new technique for filtering the Fourier transform of impedance data was used to increase the sensitivity of impedance analysis. By creating a filter specifically for impedance spectroscopy the resolution was increased. The filter was tailored to look for specific circuit elements like R//C, Warburg, or constant phase elements. As many as four peaks can be resolved using the filtering technique on symmetric cells. It may be possible to relate the different peaks to material parameters, like the oxygen exchange coefficient. The cathode grouped in order from lowest to highest ASR is

  13. Evaluation of the La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}} system as SOFC cathode material with 8YSZ and LSGM as electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Aguadero, A.; Escudero, M.J. [Centro de Investigaciones Energeticas Mediambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Alonso, J.A. [Instituto de Ciencia de Materiales de Madrid (CSIC),C/Sor Juana Ines de la Cruz 3, Campus Cantoblanco, 28049 Madrid (Spain); Daza, L. [Centro de Investigaciones Energeticas Mediambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica,(CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain)

    2008-05-31

    Materials formulated as La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}} (0 {<=} x {<=} 1) have been synthesised to be evaluated as possible cathode materials in SOFCs. Their crystal structures have been investigated by high-resolution neutron powder diffraction at RT so as to map out the phase diagram. The thermal expansion coefficients have been determined to be in the range of 10.8-13.0 x 10{sup -} {sup 6} K{sup -} {sup 1}. Total conductivity values are as good as 87 S cm{sup -} {sup 1} at 580 C for x = 0.4. In order to assess the performance of each oxide as cathode material, ac impedance measurements were carried out on La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}}/electrolyte/La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}} symmetrical cells with either LSGM or 8YSZ as electrolyte material. For all the electrode compositions studied, the best specific resistance (ASR) values were obtained with LSGM as electrolyte. The better performance of x = 0.4 and 0.6 (ASR {proportional_to} 1 and ohm; cm{sup 2} at 850 C) compositions has been associated with the magnitude of the total conductivity and the matching of the TEC values of the cathodes with those of the electrolytes. (author)

  14. Electroactive materials for rechargeable batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Huiming; Amine, Khalil; Abouimrane, Ali

    2016-10-25

    A secondary battery including a cathode having a primary cathode active material and an alkaline source material selected from the group consisting of Li.sub.2O, Li.sub.2O.sub.2, Li.sub.2S, LiF, LiCl, Li.sub.2Br, Na.sub.2O, Na.sub.2O.sub.2, Na.sub.2S, NaF, NaCl, and a mixture of any two or more thereof; an anode having an anode active material; an electrolyte; and a separator.

  15. Preparation and Electrochemical Performance of LiNi1/3Co1/3Mn1/3O2 Cathode Materials for Lithium-ion Batteries from Spent Mixed Alkaline Batteries

    Science.gov (United States)

    Yang, Li; Xi, Guoxi

    2016-01-01

    LiNi1/3Co1/3Mn1/3O2 cathode materials of lithium-ion batteries were successfully re-synthesized using mixed spent alkaline zinc-manganese batteries and spent lithium-ion batteries as the raw materials. These materials were synthesized by using a combination of dissolution, co-precipitation, calcination, battery preparation, and battery charge-discharge processes. The phase composition, morphology, and electrochemical performance of the products were determined by inductively coupled plasma optical emission spectroscopy, infrared spectra, x-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy, and charge-discharge measurements. The results showed that LiNi1/3Co1/3Mn1/3O2 cathode materials could be successfully re-synthesized at optimal preparation conditions of: co-precipitation, pH value of 8, calcination temperature of 850°C, and calcination time of 10 h. Furthermore, the electrochemical results showed that the re-synthesized sample could deliver an initial discharge capacity of up to 160.2 mAh g-1 and Coulomb efficiency of 99.8%.

  16. Magnesium Based Materials and their Antimicrobial Activity

    Science.gov (United States)

    Robinson, Duane Allan

    The overall goals of this body of work were to characterize the antimicrobial properties of magnesium (Mg) metal and nano-magnesium oxide (nMgO) in vitro, to evaluate the in vitro cytotoxicity of Mg metal, and to incorporate MgO nanoparticles into a polymeric implant coating and evaluate its in vitro antimicrobial properties. In the course of this work it was found that Mg metal, Mg-mesh, and nMgO have in vitro antimicrobial properties that are similar to a bactericidal antibiotic. For Mg metal, the mechanism of this activity appears to be related to an increase in pH (i.e. a more alkaline environment) and not an increase in Mg2+. Given that Mg-mesh is a Mg metal powder, the assumption is that it has the same mechanism of activity as Mg metal. The mechanism of activity for nMgO remains to be elucidated and may be related to a combination of interaction of the nanoparticles with the bacteria and the alkaline pH. It was further demonstrated that supernatants from suspensions of Mg-mesh and nMgO had the same antimicrobial effect as was noted when the particles were used. The supernatant from Mg-mesh and nMgO was also noted to prevent biofilm formation for two Staphylococcus strains. Finally, poly-epsilon-caprolactone (PCL) composites of Mg-mesh (PCL+Mg-mesh) and nMgO (PCL+nMgO) were produced. Coatings applied to screws inhibited growth of Escherichia coli and Pseudomonas aeruginosa and in thin disc format inhibited the growth of Staphylococcus aureus in addition to the E. coli and P. aeruginosa. Pure Mg metal was noted to have some cytotoxic effect on murine fibroblast and osteoblast cell lines, although this effect needs to be characterized further. To address the need for an in vivo model for evaluating implant associated infections, a new closed fracture osteomyelitis model in the femur of the rat was developed. Magnesium, a readily available and inexpensive metal was shown to have antimicrobial properties that appear to be related to its corrosion products and

  17. Enhanced surface exchange activity and electrode performance of (La2-2xSr2x)(Ni1-xMnx)O4+δ cathode for intermediate temperature solid oxide fuel cells

    Science.gov (United States)

    Li, Wenyuan; Guan, Bo; Yan, Jianhua; Zhang, Nan; Zhang, Xinxin; Liu, Xingbo

    2016-06-01

    Surface exchange kinetics of Ruddlesden-Popper (R-P) phase lanthanum nickelates upon Mn doping as an intermediate temperature solid oxide fuel cells (IT-SOFCs) cathode is investigated for the first time in this communication. To promote the exchange rate in oxygen reduction reaction (ORR) on nickelates, Mn is partially substituted for Ni. The oxygen exchange resistance is accurately measured by electrochemical impedance spectroscopy (EIS) with dense thin layer cathode. It is found that Mn substantially promotes the surface kinetics; a surface exchange coefficient (k) of 1.57 × 10-6 cm/s is obtained at 700 °C for La1.8Sr0.2Ni0.9Mn0.1O4+δ (Sr20Mn10), ∼80% higher than that of the undoped La2NiO4+δ (LNO). To our best knowledge, such coefficient is the highest values among the currently available R-P phase IT-SOFC cathodes. The corresponding polarization resistances (Rp) are evaluated on porous electrodes. Rp for LNO is 0.74 Ωcm2 at 750 °C, but decreases significantly to 0.42 Ωcm2 for Sr20Mn10 which is remarkably improved compared to the reported values in the literature for La2MO4+δ materials (M = transition metal). Those promising results demonstrate that Mn-doped LNO is a new excellent cathode material for IT-SOFC.

  18. Local structure in the Li-ion battery cathode material Li x(Mn yFe 1- y)PO 4 for 0 < x ≤ 1 and y = 0.0, 0.5 and 1.0

    Science.gov (United States)

    Burba, Christopher M.; Frech, Roger

    Infrared and Raman spectroscopy have been used to investigate the Li-ion battery cathode materials Li x(Mn yFe 1- y)PO 4 for 0 cycling. The lack of spectral changes during the Fe 2+/Fe 3+ redox couple (3.7 V versus Li +/Li) suggests that the P O43- anions have similar local environments in Li(Mn 0.5 (II)Fe 0.5 (II))PO 4 and Li 0.5(Mn 0.5 (II)Fe 0.5 (III))PO 4. Two-phase behavior is confirmed during the Mn 2+/Mn 3+ redox couple (4.2 V), and the infrared spectrum for (Mn 0.5 (III)Fe 0.5 (III))PO 4 is similar to that of FePO 4 since both phases contain P O43- anions coordinated only to trivalent transition metal ions. However, the P O43- anions are much more distorted in (Mn 0.5 (III)Fe 0.5 (III))PO 4 compared to FePO 4, probably as a result of deformation of the MnO 6 octahedra induced by Jahn-Teller active Mn 3+ ions in the (Mn 0.5 (III)Fe 0.5 (III))PO 4 structure. Raman spectra suggest that the carbon layer coating the Li(Mn 0.5Fe 0.5)PO 4 particles (to improve electronic contact between particles) is predominantly composed of sp 2-hybridized carbon atoms.

  19. Chromium poisoning of LSM/YSZ and LSCF/CGO composite cathodes

    DEFF Research Database (Denmark)

    Bentzen, Janet Jonna; Høgh, Jens Valdemar Thorvald; Barfod, Rasmus;

    2009-01-01

    An electrochemical study of SOFC cathode degradation, due to poisoning by chromium oxide vapours, was performed applying 3-electrode set-ups. The cathode materials comprised LSM/YSZ and LSCF/CGO composites, whereas the electrolyte material was 8YSZ. The degradation of the cathode performance...

  20. Characterization of LiFePO4 cathode by addition of graphene for lithium ion batteries

    International Nuclear Information System (INIS)

    The improvement of LiFePO4 (LFP) cathode performance has been performed by addition of Graphene (LFP+Graphene). The cathode was prepared from the active material with 5 wt % graphene and 10 wt % polyvinylidene fluoride in an n-methyl pyrrolidone solvent. Another cathode material used only 5% artificial graphite for comparison (LFP+Graphite). The crystal structure, microstructure, electronic conductivity, electrochemical impedance spectroscopy (EIS) of the cathodes were characterized by X-ray diffraction, SEM, and Impedance spectroscopy, respectively. Two half cell coin batteries were assembled using a lithium metal as an anode and LiPf6 as an electrolyte, and two cathodes (LFP+Graphene) and (LFP+Graphite). Charge discharge performance of battery was characterized by Battery analyser (BTS 8). The electronic conductivity of cathode with grapheme increased of about one order magnitude compared with the only cathode with graphite, namely from 1.97E-7S/cm (LFP+Graphite) to 1.92E-6S/cm (LFP+Graphene). The charge-discharge capacity after 10th cycles of LiFePO4 with graphene decreased of about 0.68% from 114.3 mAh/g to113.1 mAh/g, while LFP with graphite decreased of about 2.84% from 110.2 mAh/g to 107.1 mAh, at 0.1C-rates. It could be concluded that the addition of graphene has increased the ionic conductivity, and improved performance of the LFP lithium ion battery, such as higher capacity and better efficiency