La(Sr)FeO3 SOFC Cathodes with Marginal Copper Doping

(La0.8Sr0.2)0.98Fe0.98Cu0.02O3−δ can be sintered directly onto YSZ (without the need for a protective ceria interlayer). Though subject to an extended “burn‐in” period (∼200 h), anode‐supported YSZ cells using the Cu‐doped LSF achieve power densities ranging from 1.3 to 1.7 W/cm2 at 750°C and 0.7 V. These cells have also demonstrated 500 h of stable performance. The results are somewhat surprising given that XRD indicates an interaction between (La0.8Sr0.2)0.98Fe0.98‐Cu0.02O3−δ and YSZ resulting in the formation of strontium zirconate and/or monoclinic zirconia. The amount and type of reaction product was found to be dependent on cathode and electrolyte powder precalcination temperatures.