Mini-review of perovskite oxides as oxygen electrocatalysts for rechargeable zinc–air batteries

Zn–air batteries (ZABs) have been considered to be promising candidates for the next generation of energy storage devices. The sluggish kinetics of the oxygen reduction and oxygen evolution reactions (ORR and OER, respectively) at the air cathode are the key obstacles that limit the power output and energy efficiency of ZABs, and thus, it is important to develop bifunctional electrocatalysts that present high activity for both the ORR and OER, long durability, and low cost. Perovskite oxides hold great potential for fabricating air cathodes owing to their high intrinsic electrocatalytic activity, facile synthesis, and great compositional and structural flexibility. Herein, we briefly overview the development of perovskite oxides for ZAB applications. The fundamentals of ZABs and OER/ORR pathways of perovskite oxides are introduced. Strategies for activity tuning are also provided, followed by the mechanistic explanation and experimental methods of catalyst fabrication. Moreover, ZAB performance examples are also listed for convenient comparison. Lastly, remaining challenges and possible future directions of perovskite oxide-based air cathodes are discussed.