Synthesis and Performance of (La[sub 0.75]Sr[sub 0.25])[sub 1−x](Cr[sub 0.5]Mn[sub 0.5])O[sub 3] Cathode Powders of Solid Oxide Fuel Cells by Gel-Casting Technique

Abstract

The synthesis and performance of (La0.75 Sr0.25) 1-x Cr0.5 Mn0.5 O3 (x=0.0,0.1,0.2) (LSCM) cathode powders of solid oxide fuel cells by gel-casting and solid-state reaction methods were investigated. Differential thermal analysis and X-ray diffraction analysis indicate that the phase formation temperature of LSCM powders synthesized by the gel-casting technique is 50-100°C lower than that by the solid-state reaction method. The reason is related to the homogeneously distributed and immobilized precursor particles in a polymeric network, achieved during the cross-linking and gel formation steps. The LSCM cathode prepared by the gel-casting powder is shown to have a much higher electrochemical activity for the O2 reduction than that by the solid-state reaction powder. However, significant A-site nonstoichiometry (0.1 or higher) should be avoided to prevent the formation of a secondary (MnCr2) O4 spinel phase. © 2007 The Electrochemical Society.