Electrochemical Properties for BaSr۱-xGdxCo۲O۵+δ and Ba۰.۵Sr۰.۵-xGdxCoO۳-δ as a Cathode for Intermediate-Temperature Solid Oxide Fuel Cells

The structural and electrochemical properties of Gd-doped perovskite oxides were investigated to improve the performance of solid oxide fuel cell (SOFC) cathodes. Ba۰.۵Sr۰.۵-xGdxCoO۳-δ and BaSr۱-xGdxCo۲O۵+δ (BSGC) compounds were synthesized via a sol–gel thermolysis method to elucidate the effects of Gd incorporation on crystal structure, microstructure, and electrochemical activity. X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the coexistence of simple and double perovskite phases, with Gd substitution leading to finer grains (down to ۰.۴ ± ۰.۱۴ μm) and improved phase homogeneity. Area-specific resistance (ASR) and conductivity measurements revealed a strong structure–performance relationship. The optimal composition, Ba۰.۵Sr۰.۳Gd۰.۲CoO۳-δ, exhibited an exceptionally low ASR of ۰.۱۲ Ω cm² at ۷۰۰ °C which further decreased to a minimum of ۰.۰۴ Ω cm² at ۸۵۰ °C, significantly outperforming GdBaCo۲O۵+δ (GBCO), (۱.۷۶ Ω cm²). These findings demonstrate that rational structural design through rare-earth doping effectively enhances oxygen transport and electrochemical activity, providing a promising pathway for high-performance intermediate-temperature SOFC cathodes.

کلیدواژه ها:

Ba۰.۵Sr۰.۵-xGdxCoO۳-δ ، BaSr۱-xGdxCo۲O۵+δ ، Electrical conductivity ، Electrochemical properties ، Fuel cells