Tuning the electrocatalytic activity and durability of perovskite type La0.5Ba0.5CoO3-δ electrode by Pr doping

This work presents a systematic investigation of Pr-doped La 0.5−x Pr x Ba 0.5 CoO 3−δ (x = 0.05, 0.15, 0.25) cathodes, aiming to establish a structure–defect–electrochemistry correlation for developing high-performance solid oxide fuel cell (SOFC) electrodes. Moderate Pr incorporation (x = 0.15) stabilizes the cubic perovskite structure and optimizes the balance between oxygen-vacancy concentration, Co–O hybridization and lattice distortion. As a result, La 0.35 Pr 0.15 Ba 0.5 CoO 3−δ (La35Pr15) exhibits enhanced electrical conductivity of 320 S cm −1 at 800 °C and a low polarization resistance of 0.05 Ω cm 2 at 700 °C. The corresponding single cell delivers an excellent peak power density of 1.012 W cm −2 at 800 °C together with outstanding durability. Distribution of relaxation times analysis further reveals that Pr doping significantly accelerates both the intermediate-frequency oxygen surface-exchange process and the high-frequency charge-transfer kinetics, with La35Pr15 showing the strongest pO 2 responsiveness. This study demonstrates that rational Pr doping provides an effective strategy to simultaneously enhance structural stability and reaction kinetics, offering valuable insights for the design of next-generation SOFC cathodes.