Preparation of La(0.75)Sr(0.25)Cr(0.5)Mn(0.5)O(3-d) fine powders by carbonate coprecipitation for solid oxide fuel cells

A range of La(0.75)Sr(0.25)Cr(0.5)Mn(0.5)O(3-d) (LSCM) powders is prepared by the carbonate coprecipitation method for use as anodes in solid oxide fuel cells. The supersaturation ratio (R = [(NH(4))(2)CO(3)]/([La(3+)] + [Sr(2+)] + [Cr(3+)] + [Mn(2+)])) 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 C) at R = 7.5 and 12.5. By contrast, the solid-state reaction requires a higher heat-treatment temperature (1400 C). The catalytic activity of the LSCM electrodes is enhanced by using carbonate-derived powders to manipulate the electrode microstructures.