Electrolytes for Solid-Oxide Fuel Cells

Three solid-oxide fuel cell (SOFC) electrolytes, yttria-stabilized zirconia (YSZ), rare-earth-doped ceria (REDC), and lanthanum strontium gallium magnesium oxide (LSGM), are reviewed on their electrical properties, materials compatibility, and mass transport properties in relation to their use in SOFCs. For the fluorite-type oxides (zirconia and ceria), electrical properties and thermodynamic stability are discussed in relation to their valence stability and the size of the host and dopant ions. Materials compatibility with electrodes is examined in terms of physicochemical features and their relationship to the electrochemical reactions. The application of secondary ion mass spectrometry (SIMS) to detect interface reactivity is demonstrated. The usefulness of doped ceria is discussed as an Interlayer to prevent chemical reactions at the electrode-electrolyte interfaces and also as an oxide component in Mi-cermet anodes to avoid carbon deposition on nickel surfaces. Finally, the importance of cation diffusivity in LSGM is discussed, with an emphasis on the grain-boundary effects.

[1]  N. Sakai,et al.  Vaporization process of Ga from doped LaGaO3 electrolytes in reducing atmospheres , 2000 .

[2]  R. Grimes,et al.  Defect cluster formation in M2O3-doped cubic ZrO2 , 2000 .

[3]  Taniguchi Shunsuke,et al.  Degradation phenomena in the cathode of a solid oxide fuel cell with an alloy separator , 1995 .

[4]  Tohru Kato,et al.  Oxygen reduction sites and diffusion paths at La0.9Sr0.1MnO3âx/yttria-stabilized zirconia interface for different cathodic overvoltages by secondary-ion mass spectrometry , 2000 .

[5]  S. Chan,et al.  Iron oxide as an effective sintering aid and a grain boundary scavenger for ceria-based electrolytes , 2004 .

[6]  John B. Goodenough,et al.  Increasing Power Density of LSGM-Based Solid Oxide Fuel Cells Using New Anode Materials , 2001 .

[7]  J. Kilner.  Fast oxygen transport in acceptor doped oxides , 2000 .

[8]  Tohru Kato,et al.  Active Sites Imaging for Oxygen Reduction at the La0.9Sr0.1MnO3 − x /Yttria‐Stabilized Zirconia Interface by Secondary‐Ion Mass Spectrometry , 1998 .

[9]  N. Sakai,et al.  Determination of hydrogen solubility in oxide ceramics by using SIMS analyses , 1999 .

[10]  E. Kisi.  Zirconia engineering ceramics, old challenges - new ideas , 1998 .

[11]  J. Wolfenstine.  Rate-controlling species for creep of the solid state electrolyte: doped lanthanum gallate , 1999 .

[12]  H. Yokokawa.  Understanding Materials Compatibility , 2003 .

[13]  N. Sakai,et al.  Solid Oxide Electrolytes for High Temperature Fuel Cells , 2005 .

[14]  Jin-ho Kim,et al.  Partial electronic conductivity and electrolytic domain of La0.9Sr0.1Ga0.8Mg0.2O3−δ , 2001 .

[15]  N. Sakai,et al.  Thermodynamic Analysis of Reaction Profiles Between LaMO3 ( M = Ni , Co , Mn ) and ZrO2 , 1991 .

[16]  N. Sakai,et al.  Thermodynamic stabilities of perovskite oxides for electrodes and other electrochemical materials , 1992 .

[17]  N. Choudhury,et al.  Performance characteristics of solid electrolytes under steady-state conditions. [Yttria-doped thoria, 1600/sup 0/C] , 1971 .

[18]  J. Goodenough,et al.  Characterization of Sr‐Doped LaMnO3 and LaCoO3 as Cathode Materials for a Doped LaGaO3 Ceramic Fuel Cell , 1996 .

[19]  R. Grimes,et al.  Defect cluster formation in M2O3-doped CeO2 , 1999 .

[20]  Y. Matsuzaki,et al.  Dependence of SOFC Cathode Degradation by Chromium-Containing Alloy on Compositions of Electrodes and Electrolytes , 2001 .

[21]  Tatsumi Ishihara,et al.  Doped LaGaO3 Perovskite Type Oxide as a New Oxide Ionic Conductor , 1994 .

[22]  Y. Xiong,et al.  Hole and Electron Conductivities of 20 mol % ­ REO 1.5 Doped CeO2 (RE = Yb, Y, Gd, Sm, Nd, La) , 2004 .

[23]  Tohru Kato,et al.  Design of metal/oxide interfaces for the direct introduction of hydrocarbons into SOFCs , 2004 .

[24]  Y. Xiong,et al.  Protons in ceria and their roles in SOFC electrode reactions from thermodynamic and SIMS analyses , 2004 .

[25]  B. Chowdari,et al.  Solid State Ionics: The Science and Technology of Ions in Motion , 2004 .

[26]  L. Gauckler,et al.  Sintering and properties of nanosized ceria solid solutions , 2000 .

[27]  N. Sammes,et al.  Physical, chemical and electrochemical properties of pure and doped ceria , 2000 .

[28]  H. Yokokawa.  Generalized chemical potential diagram and its applications to chemical reactions at interfaces between dissimilar materials , 1999 .