Characterization of SmBa0.5Ca0.5CoCuO5+δ with exsolved CaCuO2-type phase as an advanced cathode material of solid oxide fuel cells

Abstract The cathode is a critical component in the utilization of solid oxide fuel cells (SOFCs) technique. Herein, the perovskite oxide SmBa0.5Ca0.5CoCuO5+δ (SBCCC) with exsolved CaCuO2-type phase was proposed as an advanced cathode material of SOFCs. It is synthesized through a simple sol-gel method and displays a good chemical and thermal matching with Gd0.1Ce0.9O1.95 electrolyte, high electrocatalytic activity and durability to the oxygen reduction reaction. Its thermal expansion coefficient is 14.3 × 10−6 °C−1, which is very close to that of Gd0.1Ce0.9O1.95 electrolyte (11.5 × 10−6 °C−1). The area-specific resistance low to 0.076 Ω cm2 (700 °C) and output power density high to 1.23 W cm−2 (800 °C) were obtained for the SBCCC-based symmetrical and single cells. A stable and non-attenuating output current density was acquired for the SBCCC-based single-cell working at 750 °C and 0.7 V for 200 h. These results demonstrate that SBCCC with exsolved CaCuO2-type phase is an attractive electrocatalyst for SOFC application.