Antimony-doped Bi0.5Sr0.5FeO3−δ as a novel Fe-based oxygen reduction electrocatalyst for solid oxide fuel cells below 600 °C

Abstract

The perovskite oxide Bi_0.5Sr_0.5Fe_0.90Sb_0.10O_3−δ (BSFS) is evaluated as an efficient Fe-based cathode for low-temperature solid oxide fuel cells (LT-SOFCs). The BSFS material possesses a single cubic perovskite structure. The Sb-doping strategy is proven to be beneficial towards the structure stability of pristine Bi_0.5Sr_0.5FeO_3−δ. A BSFS cathode shows an efficient electrocatalytic activity for the oxygen reduction reaction (ORR). The lowest polarization resistance (R_p) value of 0.098 Ω cm² is obtained and the anode supported fuel cell gives a remarkable peak power density of 0.95 W cm² at 600 °C, which is comparable to that of state-of-the-art Co-based materials. The prominent performance is ascribed to the comparable TEC value and the large amount of oxygen vacancies generated at high temperatures. Moreover, the BSFS cathode also exhibits excellent CO₂ tolerance under exposure to 10 vol% CO₂ at 600 °C for 24 h. These features highlight the potential applicability of the BSFS material as a highly promising cathode material for LT-SOFCs.