Electrochemical Properties for BaSr1-xGdxCo2O5+δ and Ba0.5Sr0.5-xGdxCoO3-δ as a Cathode for Intermediate-Temperature Solid Oxide Fuel Cells

Sara Tafaroji

The structural and electrochemical properties of Gd-doped perovskite oxides were investigated to improve the performance of solid oxide fuel cell (SOFC) cathodes. Ba_0.5Sr_0.5-xGd_xCoO_3-δ and BaSr_1-xGd_xCo₂O_5+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 0.4 ± 0.14 μm) and improved phase homogeneity. Area-specific resistance (ASR) and conductivity measurements revealed a strong structure–performance relationship. The optimal composition, Ba_0.5Sr_0.3Gd_0.2CoO_3-δ, exhibited an exceptionally low ASR of 0.12 Ω cm² at 700 °C which further decreased to a minimum of 0.04 Ω cm² at 850 °C, significantly outperforming GdBaCo₂O_5+δ (GBCO), (1.76 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.

Iranian Journal of Materials Science and Engineering

Electrochemical Properties for BaSr1-xGdxCo2O5+δ and Ba0.5Sr0.5-xGdxCoO3-δ as a Cathode for Intermediate-Temperature Solid Oxide Fuel Cells