Progress and Perspective of Noble-Metal-Free Bifunctional Oxygen Electrocatalysts for Zinc-Air Batteries

Abstract

Rechargeable Zn-air batteries (ZABs) have attracted widespread attention due to their advantages, such as high energy density, low price, and environmental friendliness. However, the sluggish kinetics of ORR/OER greatly prevent the practical application of rechargeable ZABs. In recent years, efficient, durable, and cost-effective bifunctional catalysts are developed to accelerate the kinetics of ORR/OER and enhance the performance of ZABs. This review provides a systematic overview of ZABs and describes the standards of bifunctional oxygen electrocatalysts. The latest research progress in the development of non-noble metal-based and nano-metallic electrocatalysts for the air electrode of ZABs is systematically summarized, including the classification, design, synthesis methods, active site structures, and mechanism. Finally, the challenges faced by bifunctional catalysts and probable solutions are proposed. This review will provide a comprehensive guidance for development of efficient oxygen electrocatalyst in the future.