SrCo1−yTiyO3−δ as potential cathode materials for intermediate-temperature solid oxide fuel cells

The perovskites SrCo1−yTiyO3−δ (SCTy, 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 La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) electrolyte. SCTy 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 SCTy composites relative to the undoped SrCoO3−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 SCTy cathodes on the LSGM electrolyte gradually increase from 0.084 Ω cm2 at y = 0.05 to 0.091 Ω cm2 at y = 0.20 with increasing Ti content at 750 °C. Single-cells that used SCTy 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 SCTy cubic perovskites demonstrate considerable potential for application in IT-SOFC cathodes.

► The high-temperature cubic phase of SrCoO3−δ was stabilized at room temperature by substituting Ti for Co.
► The substitution of Ti for Co greatly improved the electrical conductivity of the SrCo1−yTiyO3−δ.
► SrCo1−yTiyO3−δ displayed good electrochemical performance as IT-SOFC cathodes.