Synergistic Dual-Site Modulation Enabling High-Performance Cobalt-Free Perovskite Cathodes for...

Solid oxide fuel cells (SOFCs) have emerged as promising energy conversion technologies due to their high efficiency and environmental benefits. Conventional cobalt-based perovskite oxides, though widely employed as cathode materials with favorable oxygen reduction reaction activity, suffer from high cost and thermal instability, hindering their large-scale deployment. To address these limitations, a novel cobalt-free perovskite oxide, Ba_0.8La_0.2Fe_0.95Y_0.05O_3-δ (BLFY), is designed through dual-site synergistic substitution of La at A-site and Y at B-site based on a BaFeO_3-δ framework to enhance structural stability, oxygen vacancy concentration, and oxygen-ion transport kinetics. Comprehensive physicochemical and electrochemical characterizations confirm that BLFY adopts a single-phase cubic perovskite structure with abundant oxygen vacancies and high oxygen-ion mobility. As a result, the BLFY electrode demonstrates excellent electrochemical performance, delivering an ultralow area-specific resistance of only 0.07 Ω·cm² and a high peak power density of 1280 mW·cm^-2 at 600°C, outperforming its singly modified counterparts (Ba_0.8La_0.2FeO_3-δ and BaFe_0.95Y_0.05O_3-δ) and multiple benchmark cobalt-based cathodes. It also maintains outstanding thermal and operational stability over extended durations. These findings highlight the effectiveness of dual-site synergistic design in engineering high-performance cobalt-free perovskite cathodes, offering a promising route toward cost-efficient and durable SOFCs for intermediate-temperature operation.