Sr- and Mg-doped LaGaO3 powder synthesis by carbonate coprecipitation

Sr- and Mg-doped LaGaO3 (LSGM) and Co-doped LSGM (LSGMC) powders were synthesized by coprecipitation using ammonium carbonate or ammonium bicarbonate precipitant. Precursor, calcined particles, and sintered pellets of LSGM were characterized using TGA, XRD, and SEM. The calcined powders of LSGM showed uniform microstructures with nearly spherical morphology and average particle size of 100–200 nm. The ionic conductivity of the sintered LSGM and LSGMC pellets at 1400 °C was 4.5 × 10−2 S/cm and 1.13 S/cm at measuring temperature of 800 °C, respectively. The internal microstructure was observed by FIB-SEM and it was found that the internal pores affected adversely on the ionic conductivity of the sintered LSGM pellets. The ionic conductivity of the as-prepared powders would be improved by optimization of the preparation process. The results of this study indicated that ammonium carbonate coprecipitation could be used as a convenient and economic method to produce LSGM electrolyte for low temperature SOFCs.