Optimized Lanthanum Ferrite-Based Cathodes for Anode-Supported SOFCs

Three cathode compositions (La0.8Sr0.2FeO3-delta, La0.7Sr0.3Fe0.8Ni0.2O3-delta, and LaNi0.6Fe0.4O3-delta) were tested as solid oxide fuel cell (SOFC) cathodes at operating temperatures from 650 to 750 C. Sintering temperatures were established for each cathode composition to provide optimised cell performance. La0.8Sr0.2FeO3-delta exhibited the highest power density ( > 900 mW/cm2 at 750 C and 0.7 V), and indicated excellent performance stability over a 300 h period. This suggested that it may be a viable cathode for intermediate temperature SOFCs. However, at present, for temperatures below 750 C, the power densities (about 300 mW/cm2 at 650 C) are somewhat low, especially considering that further reductions in performance would be expected in an actual stack due to ohmic losses through interconnects, etc. 10 refs.