Synergistic Dual‐Site Modulation Enabling High‐Performance Cobalt‐Free Perovskite Cathodes for Intermediate‐Temperature Solid Oxide Fuel Cells

ABSTRACT 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 _0.8 La _0.2 Fe _0.95 Y _0.05 O _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·cm ² and a high peak power density of 1280 mW·cm ⁻² at 600°C, outperforming its singly modified counterparts (Ba _0.8 La _0.2 FeO _3‐δ and BaFe _0.95 Y _0.05 O _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.