Highly electrocatalytic active and durable Fe-based perovskite oxygen reduction electrode for solid oxide fuel cells

Developing high efficiency catalysts in the application of solid oxide fuel cells (SOFCs) receive increasing attention. In this work, Fe-based perovskite oxide Bi0.5Sr0.5Fe0.95Mo0.05O3-δ (BSFM) is evaluated as novel cathode electrocatalyst for SOFCs. The phase structure, thermal expansion behavior, CO2 tolerance and electrochemical properties of the BSFM cathode are intensively investigated. BSFM cathode presents outstanding electrode activity for the oxygen reduction reaction (ORR). It achieves the lowest polarization resistance of 0.12 Ω cm2 at 700 °C in air, and excellent current density of 250 mA cm2 at a constant overpotential of 70 mV. The fuel cell with the BSFM cathode shows the maximum power density of 1.07 W cm−2 at 700 °C. In addition, the ORR rate-limiting step for BSFM cathode is identified to be the oxygen adsorption and dissociation process on the electrode. These significant electrochemical results promise that the BSFM oxide is a prospective cathode electrocatalyst for SOFCs.