Thermodynamic Stabilities of La[sub 2]Zr[sub 2]O[sub 7] and SrZrO[sub 3] in SOFC and Their Relationship with LSM Synthesis Processes

Abstract

A Sr-substituted perovskite (LSM) and yttria-stabilized zirconia mixture was investigated by thermodynamic calculations to understand the factors affecting the stabilities of and , the two zirconates, at different conditions in solid oxide fuel cell. Two sets of independent experimental investigations were done: (i) The thermodynamic stabilities of the two zirconates in and air to simulate the phase equilibria at different conditions. The experimental data proved that thermodynamic calculations were reliable and they can be used to provide guidance to reduce/prevent the formation of the two zirconates. (ii) The stabilities of zirconates with LSM made by fusion and conventional methods were compared in air and . The fused LSM powders from Saint-Gobain show less zirconate phase formation in all conditions than in conventional synthesis methods.