Boosting the electrocatalytic performance of Fe-based perovskite cathode electrocatalyst for solid oxide fuel cells

Abstract The development of cathode materials with excellent electrocatalytic activity and CO2 tolerance is an important direction for the wide application of solid oxide fuel cells. Herein, the cobalt-free perovskite oxides Bi0.5Sr0.5Fe1-xVxO3-δ (BSFVx, x = 0.025, 0.05 and 0.075) are developed as the efficient cathode electrocatalysts for SOFCs. The V-doping strategy is beneficial to improve the thermal stability, CO2 tolerance and electrochemical performance of undoped Bi0.5Sr0.5FeO3-δ. Among all samples, Bi0.5Si0.5Fe0.95V0.05O3-δ (BSFV0.05) cathode presents excellent oxygen reduction reaction activity, achieving a lower polarization resistance of 0.076 Ω cm2 and the peak power density of the single cell with the BSFV0.05 cathode reaches to 1.16 W cm−2 at 700 °C, which can be comparable to those of the representative cobalt-based cathodes. Furthermore, the improved CO2 tolerance of the BSFV0.05 cathode can be ascribed to the high acidity of the V5+ and the larger average bonding energy in the oxide.