Enhancing electrochemical performance of composite cathodes for solid oxide fuel cells through morphology optimization of raw material powders

The performance of cathode in solid oxide fuel cells (SOFCs) depends not only on material composition but also on microstructure. The morphology of raw materials often has an important influence on cathode microstructure. Herein, Ce_0.8Sm_0.2O_1.9 (SDC) powders with different morphology are synthesized by sol-gel method via varying calcining temperatures from 500 to 1200 ^oC, and then introduced into GdBaCo₂O_5+δ (GBCO) to form composite cathodes by mechanical mixing. The experimental results show that the introduction of SDC powder calcined at 1000 ^oC can more effectively improve cathodic electrochemical performance, owing to its good particle dispersion and smaller, more uniform particle size as compared to SDC calcined at other temperatures. The resultant composite cathode shows superior oxygen reduction reaction catalytic activity, a cathodic polarization resistance of 0.048 Ω cm² is achieved at 700 °C. This study highlights the important role of morphology optimization of raw material powders in designing outstanding SOFC cathodes.