Single/dual-metal active-site oxides for rechargeable zinc-air batteries: Fundamental properties, advancements, challenges, and future perspectives

Rechargeable zinc-air batteries (RZABs) are considered one of the most promising candidates for advanced energy storage and conversion in the near future. The RZABs efficiency is closely tied to the performances of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) occurring at the air cathode. Metal-oxide catalysts occupy a crucial role in reducing the reaction energy barriers and improving the ORR and OER performance. Two types of metal-oxide electrocatalysts used in RZABs are single-metal active-site (SMAS) and dual-metal active-site (DMAS) oxides, both of which significantly impact the efficiency and durability of ORR and OER. This review presents a comprehensive analysis of the advancements in SMAS and DMAS, especially single-phase DMAS oxides, offering significant insights into the design of high-performance bifunctional oxygen electrocatalysts and RZABs.