Constructing a high-performance bifunctional MnO2-based electrocatalyst towards applications in rechargeable zinc-air batteries

Slow oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the liquid-solid-gas interface of the air cathode have always been a big obstacle for different renewable energy devices, especially rechargeable zinc-air batteries (RZABs). In recent years, manganese dioxide based electrocatalysts have been extensively investigated for their variety of morphologies and structures, relatively high activity, rich resources and environmental friendliness. Not only that, manganese dioxide based electrocatalysts can be used as cathode materials for zinc ion batteries, which is conducive to the development of zinc-air ion batteries. This review serves to summarize the latest research progress on manganese dioxide as a high-performance bifunctional (both OER and ORR) catalyst for zinc-air batteries. Although MnO2 has many advantages and has been studied extensively, its activity and stability still need to be improved. This review aims to guide the design and widespread application of Mn-based electrocatalysts in the future by summarizing various measures to enhance performance.