Recent Advances on Nonprecious-Metal-Based Bifunctional Oxygen Electrocatalysts for Zinc–Air Batteries

Zinc–air batteries (ZABs) are among the most promising electrochemical energy storage devices which feature high energy density, decent rechargeability, low cost, and eco-friendliness. However, the current performance of ZABs is hampered by the sluggish kinetics of the oxygen electrocatalysis on the air electrodes. The central task is to rationally design nonprecious metal-based electrocatalysts with excellent activity, durability, and low cost. Herein, the fundamentals of ZABs and reaction mechanisms for oxygen reduction and evolution reactions at the air electrodes are briefly introduced. Based on these acknowledgments, the current advances in bifunctional oxygen electrocatalysts based on nonprecious metal materials for ZABs are reviewed and their perspectives for the near future are highlighted. In addition, the limitations, development trends, and future challenges in this field are also discussed.