SrCo 1− yTi yO 3− δ as potential cathode materials for intermediate-temperature solid oxide fuel cells

Abstract

The perovskites SrCo 1− y Ti y O 3− δ (SCT y, y = 0.00–0.20) are synthesized and assessed as potential cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) based on the La 0.9Sr 0.1Ga 0.8Mg 0.2O 3− δ (LSGM) electrolyte. SCT y composites with y ≥ 0.05 adopt a cubic perovskite structure with thermal stability between 30 °C and 1000 °C in air. Substitution of Ti significantly enhances the electrical conductivity of the SCT y composites relative to the undoped SrCoO 3− δ . The highest electrical conductivity of the sample with y = 0.05 varied from 430 S cm −1 to 160 S cm −1 between 300 °C to 800 °C in air. The area-specific resistances of the SCT y cathodes on the LSGM electrolyte gradually increase from 0.084 Ω cm 2 at y = 0.05 to 0.091 Ω cm 2 at y = 0.20 with increasing Ti content at 750 °C. Single-cells that used SCT y cathodes with y = 0.05, 0.10, 0.15, and 0.20 on a 300 μm-thick LSGM electrolyte achieve peak power densities of 793, 608, 525, and 425 mW cm −2 at 800 °C, respectively. These novel SCT y cubic perovskites demonstrate considerable potential for application in IT-SOFC cathodes.