• Title/Summary/Keyword: oxide cathode

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Analyses on the Physical and Electrochemical Properties of Al2O3 Coated LiCoO2 (리튬이차전지용 양극 활물질(LiCoC2)의 표면처리의 특성 분석 및 전기화학적 특성 고찰)

  • Chang, Youn-Han;Choi, Sei-Young
    • Journal of the Korean Electrochemical Society
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    • v.10 no.3
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    • pp.184-189
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    • 2007
  • The importance of secondary battery industry is getting excited according to the development of battery industry as a high efficiency energy supplier of electronic machine of mobile information such as mobile phone, lap-top computer, PDA. It is rasing the interest about security of safety and high efficiency of cathode material for main part of secondary lithium battery. The cathode material which has been used like $LiCoO_2,\;LiMn_2O_4,\;LiNi_xCo_yMn_zO_2,\;LiNi_xCo_yM_zO_2$ (M=Al, Zr, Mg etc.,) the most typical material is $LiCoO_2$. But it is studying the development of substitute such as efficiency amelioration of $LiCoO_2$, thetiary element, olivine element because of the capacity of $LiCoO_2$, the matter of security; especially the betterment of efficiency, security research of safety has been actively processed in domestic and overseas about surface coating treatment of active cathode which is using oxide ($M_xO_3$). This study analyses side effect of battery according to increase of surface treatment, formation of precipitation for reagent condensation, non-reagent residue of oxide ($M_xO_3$) which is remains during the surface treatment of $LiCoO_2$; conducts study of new process, the consideration of the electrochemical property to improve oxide solution of mixing rate, mixture of surface treatment, dryness, calcinations conditionetc.

Electrochemical Investigation in Particle Size and Thermal Cycles of Sr Doped Layered Perovskite Based Composite Cathodes for Intermediate Temperature-operating Solid Oxide Fuel Cell (중·저온형 고체산화물 연료전지 공기극의 적용을 위한 Sr이 치환된 이중층 페로브스카이트 기반 복합공기극 물질의 분말 크기 및 열 사이클에 따른 전기화학특성 분석)

  • Kim, Jung-Hyun
    • Journal of the Korean Electrochemical Society
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    • v.14 no.3
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    • pp.176-183
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    • 2011
  • The electrochemical characteristics from various particle sizes of $Ce_{0.9}Gd_{0.1}O_{2-{\delta}}$ (CGO91) in composite cathode comprised of the samarium-strontium doped layered perovskite ($SmBa_{0.5}Sr_{0.5}Co_2O_{5+{\delta}}$) and CGO91 have been investigated for possible application as a cathode material for an intermediate temperature-operating solid oxide fuel cell (IT-SOFC). The area specific resistances (ASRs) of composite cathodes with CGO91 having smaller particle size ($0.4\sim42{\mu}m$) and SBSCO of 1 : 1 ratio (50wt% SBSCO and 50 wt% CGO91, SBSCO: 50) give the lowest ASR of $0.10{\mu}cm^2$ at $600^{\circ}C$ and $0.013{\Omega}cm^2$ at $700^{\circ}C$. However, composite cathodes with having relatively bigger CGO91 particle size show the two times higher ASR results than those of SBSCO : 50. From the 10 times thermal cycles in SBSCO : 50, the ASRs of SBSCO : 50 increased from $0.0193{\Omega}cm^2$ to $0.094{\Omega}cm^2$ at $700^{\circ}C$, however, the ASR value was maintained after 7 times of thermal cycling.

Variation of Oxygen Nonstoichiometry of Porous $La_{0.6}Ca_{0.4}MnO_{3-{\delta}}$ SOFC-Cathode under Polarization

  • Mizusaki, Junichiro;Harita, Hideki;Mori, Naoya;Dokiya, Masayuki;Tagawa, Hiroaki
    • The Korean Journal of Ceramics
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    • v.6 no.2
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    • pp.177-182
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    • 2000
  • At the porous $La_{0.6}Ca_{0.4}MnO_{3-{\delta}}$(LCM)/YSZ electrodes of solid oxide fuel cells (SOFC), the electrochemical redox reaction of oxygen proceeds via the triple boundary (TPB) of gas/LCM/YSZ. The surface diffusion of adsorbed oxygen on LCM has been proposed as the rate determining process, assuming the gradient of oxygen chemical potential from the outer surface of porous layer to TPB. Along with the formation of this gradient, oxygen nonstoichiometry in the bulk of LCM may varies. In this paper, an electrochemical technique was described precisely to determine the variation of oxygen content in LCM of porous LCM/YSZ under polarization. It was shown that the oxygen potential in LCM layer under large cathodic polarization is much lower than that in the gas phase, being determined from the electrode potential and Nernst equation.

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Electrochemical Studies and Chemical Synthesis of Nanoscale YSZ Electrolyte Powder for Solid Oxide Fuel Cell (고체산화물 연료전지용 나노 YSZ전해질 분말 합성 및 단위셀의 전기화학적 평가)

  • Shin, Yu-Cheol;Kim, Young-Mi;Kim, Ho-Sung
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.299-302
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    • 2009
  • Oxygen ionic conductors of YSZ electrolyte in SOFC unit cell are applied to anode and cathode as well as electrolyte to have triple-phase-boundaries(TPB) of electrochemical reaction, and it is required to decrease the sintering temperature of anode-supported electrolyte by the nanoscale of YSZ powder.In this report, nanoscale YSZ powder was synthesized by the chemical co-precipitation method. The particle size, surface area and morphology of the powder were observed by SEM and BET. Thin film electrolyte of under 10㎛ was fabricated by tape casting using the synthesized YSZ powder, and ionic conductivity and gas permiability of electrolyte film were evaluated. Finally, the SOFC unit cell was fabricated using the anode-supported electrolyte prepared by a tape casting method and co-sintering. Electrochemical evauations of the SOFC unit cell, including measurements such as power density and impedance, were performed and analyzed.

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Comparative Performance Analysis of Pressurized Solid Oxide Fuel Cell / Gas Turbine Hybrid Systems Considering Different Cell Inlet Preheating Methods (셀 입구 예열방법에 따른 가압형 고체산화물 연료전지/가스터빈 하이브리드 시스템의 성능 비교 해석)

  • Yang Won Jun;Kim Jae Hwan;Kim Tong Seop
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.6 s.237
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    • pp.722-729
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    • 2005
  • Design analysis of the solid oxide fuel cell and gas turbine combined power system is performed considering different methods for preheating cell inlet air. The purpose of air preheating is to keep the temperature difference between cell inlet and outlet within a practical design range thus to reduce thermal stress inside the cell. Three different methods considered are (1) adopting a burner in front of the cell, (2) adopting a preheater (heat transfer from the main combustor) in front of the cell and (3) using recirculation of the cathode exit gas. For each configuration, analyses are carried out for two values of allowable maximum cell temperature difference. Performance characteristics of all cases are compared and design limitations are discussed. Relaxation of the cell temperature difference (larger difference) is proved to ensure higher efficiency. Recirculation of the cathode exit gas exhibits better performance than other methods and this advantage becomes more prominent as the constraint of the cell temperature difference becomes more severe (smaller temperature difference).