Pr-Doping Motivating the Phase Transformation of the BaFeO₃-_δ Perovskite as a High-Performance Solid Oxide Fuel Cell...

Intermediate temperature solid oxide fuel cells (IT-SOFCs) have been extensively studied due to high efficiency, cleanliness, and fuel flexibility. To develop highly active and stable IT-SOFCs for the practical application, preparing an efficient cathode is necessary to address the challenges such as poor catalytic activity and CO₂ poisoning. Herein, an efficient optimized strategy for designing a high-performance cathode is demonstrated. By motivating the phase transformation of BaFeO_3-δ perovskites, achieved by doping Pr at the B site, remarkably enhanced electrochemical activity and CO₂ resistance are thus achieved. The appropriate content of Pr substitution at Fe sites increases the oxygen vacancy concentration of the material, promotes the reaction on the oxygen electrode, and shows excellent electrochemical performance and efficient catalytic activity. The improved reaction kinetics of the BaFe_0.95Pr_0.05O_3-δ (BFP05) cathode is also reflected by a lower electrochemical impedance value (0.061 Ω·cm² at 750 °C) and activation energy, which is attributed to high surface oxygen exchange and chemical bulk diffusion. The single cells with the BFP05 cathode achieve a peak power density of 798.7 mW·cm^-2 at 750 °C and a stability over 50 h with no observed performance degradation in CO₂-containing gas. In conclusion, these results represent a promising optimized strategy in developing electrode materials of IT-SOFCs.