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

Abstract A range of La 0.75 Sr 0.25 Cr 0.5 Mn 0.5 O 3− δ (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 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.