Preparation of La0.75Sr0.25Cr0.5Mn0.5O3-delta fine powders by carbonate coprecipitation for solid oxide fuel cells

Abstract

A range of La0.75Sr0.25Cr0.5Mn0.5O3-delta (LSCM) powders is prepared by the carbonate coprecipitation method for use as anodes in solid oxide fuel cells. The supersaturation ratio (R = [(NH4)(2)CO3]/([La3+] + [Sr2+] + [Cr3+] + [Mn2+])) during the coprecipitation determines the relative compositions of La, Sr, Cr, and Mn. The composition of the precursor approaches the stoichiometric one at the supersaturation range of 4 < R < 12.5, whereas Sr and Mn components are deficient at R < 4 and excessive at R = 25. The fine and phase-pure LSCM powders are prepared by heat treatment at very low-temperature (1000 degrees C) at R = 7.5 and 12.5. By contrast, the solid-state reaction requires a higher heat-treatment temperature (1400 degrees C). The catalytic activity of the LSCM electrodes is enhanced by using carbonate-derived powders to manipulate the electrode microstructures. (C) 2009 Elsevier B.V. All rights reserved.