Electrolytes for solid-oxide fuel cells

Three solid-oxide fuel cell (SOFC),electrolytes, yttria-stabiliied zirconia (YSZ),rare-earth-doped earth-doped (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 Ni-cermet anode's 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.