A-Site Engineered High Entropy Perovskite Oxides for Rechargeable Zinc-Air Batteries

High Resolution Image Download MS PowerPoint Slide High-entropy perovskite oxides (HEPOs) combine the compositional flexibility of perovskite oxides with the structural stability of high-entropy oxides, which enables tunable physicochemical properties and robust electronic structures. These attributes make HEPOs particularly attractive as bifunctional air cathode catalysts for alkaline rechargeable zinc−air batteries (ZABs). In this work, we synthesized a series of HEPOs with different A-site cation compositions, (LaX)(FeCoCrMnZn)O 3 (X = Sr, Nd, Ca), referred to as LaSr, LaNd, and LaCa. We effectively tailored the work function and oxygen vacancy concentrations by employing an A-site doping strategy, which significantly impact HEPOs electrocatalytic performance. Among the samples, LaNd displayed the lowest oxygen evolution reaction (OER) overpotential and fastest reaction kinetics, resulting from its reduced work function and enhanced oxygen vacancy density. Both mass and specific activity analyses confirmed LaNd’s superior OER performance compared to the other A-site variants. When incorporated as a cathode in ZABs, LaNd also exhibited excellent cycling stability and a prolonged operational lifetime, while maintaining competitive oxygen reduction reaction (ORR) activity, underscoring its capability as a reliable bifunctional catalyst. These findings demonstrate that precise A-site cation tuning, while maintaining a stable crystal structure, allows for controlled electronic structure and oxygen vacancy engineering, offering a practical route to optimize HEPO-based air cathodes and enhance the performance and durability of rechargeable ZABs.