Recent Advances in the Development of Single‐Atom Catalysts for Oxygen Electrocatalysis and Zinc–Air Batteries

Rechargeable zinc–air batteries (ZABs) are presently attracting a lot of attention for electrical energy storage, owing to their low manufacturing cost and very high theoretical specific energy density. Currently, the large‐scale application of ZABs is hampered by the sluggish kinetics of the oxygen‐reduction reaction (ORR) and oxygen evolution reaction (OER), which underpin battery discharging and charging processes, respectively. In recent years, metal single‐atom catalysts (SACs) have emerged as promising candidates for driving oxygen electrocatalysis in ZABs, offering both high electrocatalytic activity and high metal atom utilization through unique metal coordination environments (typically porphyrin‐like MNx species on N‐doped carbon supports). Herein, recent breakthroughs in the design of SACs for ORR and OER electrocatalysis are summarized, with a general view towards improving ZAB performance. This Review begins by introducing the operating principles of ZABs and the reaction mechanisms of the ORR and the OER on the air electrode, after which the various types of SAC‐based materials developed to date for oxygen electrocatalysis and ZABs are discussed. Special emphasis is placed on the relationships between the structure of the SAC active site and electrocatalytic performance. Finally, challenges and opportunities for SACs in practical ZABs are explored. Recent breakthroughs in the development of metal single‐atom catalysts (SACs) for the oxygen reduction reaction and the oxygen evolution reaction are reviewed, with the goal of improving the future performance of zinc–air batteries. Particular emphasis is placed on the relationships between the structure of the metal SAC sites and electrocatalytic performance in oxygen electrocatalysis.