An efficient and durable perovskite electrocatalyst for oxygen reduction in solid oxide fuel cells

Achieving superior electrocatalytic activity and thermal/chemical stability of cathode materials is the key to high-performance and durable solid oxide fuel cells (SOFC). Here, we present a barium and praseodymium co-substituted perovskite Bi_0.7Pr_0.1Ba_0.2FeO_3-δ (BPBF), a cubic-symmetry oxide phase, as a candidate cathode material for SOFC, with a focus on its crystalline structure, oxygen transport, electrocatalytic activity, as well as structural and chemical stability. The BPBF-based cathode delivers superior electroactivity, with a polarization area-specific-resistance as low as 0.056 Ω cm² at 700 °C in symmetrical cells. Surprisingly, when exposed to both air and 1 vol% CO₂-containing air at 600 °C for 100 h, the electrode activity remains constant. The prominent thermal and chemical (CO₂ tolerance) stability can be ascribed to co-substitution of barium and praseodymium and high acidity of bismuth ions. Endowed with favorable electrocatalytic activity and excellent durability, the BPBF-based material can be a promising cathode to facilitate commercialization of SOFC technology.