Evaluation of La0.3Ca0.7Fe1−yCryO3−δ (y = 0.1-0.3) cathodes for intermediate temperature solid oxide fuel cells

Perovskite-type (ABO3) complex oxides of La0.3Ca0.7Fe1−yCryO3−δ (y = 0.1-0.3) system were prepared via a glycine-nitrate process. In view of utilization as cathode for intermediate temperature solid oxide fuel cells, the structure, electrical conducting, thermal expansion and electrochemical properties of the oxides were investigated in comparison with their strontium counterparts (La0.3Sr0.7Fe1−yCryO3−δ, y = 0.1-0.3). Differences in the properties between the two systems were interpreted in relation with their structural characteristics. The results corroborate the effectiveness of modulating A-site dimension in modifying the overall properties of iron chromium-based perovskite-type cathode materials. The calcium compositions with y = 0.2 and y = 0.3, respectively, exhibit the optimal overall properties, superior to their strontium counterparts. The good overall properties of the two compositions, including suitable thermal expansion coefficients (11-12 × 10−6 K−1 between 40 and 1000 °C), low polarization resistances (∼0.12 Ω cm2 at 800 °C) and acceptable electrical conductivity (∼40 S cm−1 at 800 °C), demonstrate their potential in cathode utilization.