Progress and challenges in engineering the atomic structure of oxygen electrocatalysts for zinc-air batteries

Rechargeable zinc-air batteries are presently regarded as promising candidates for next-generation energy storage systems, owing to their high specific energy density, environmental-friendliness, and safety. Despite these advantages, zinc-air batteries still suffer from low energy efficiency and poor cycle life due to sluggish electrochemical kinetics of oxygen species. Therefore, modification strategies for catalysts to improve the performance of rechargeable zinc-air batteries are necessary. This review focuses on strategies used for modifying catalysts from nanoarchitecture and electronic structural perspectives. In the review, we first describe the overall mechanism and component of the zinc-air battery. Then, we analyze the effects of charge redistribution and enhanced electron transport within the molecular structures of the air cathode by forming heterogeneous nanostructures. We also analyze the relationship between modulation of d-band center of the catalyst and the coordination environment of atom within the air cathode. We also describe the strategies for incorporating vacancies in the molecular structure to improve the performance of air cathodes. Finally, we provide a general perspective on the overall limitations of current zinc-air batteries.