Recent Progress in Non-Precious Catalysts for Metal-Air Batteries

Electrical energy storage and conversion is vital to a clean, sustainable, and secure energy future. Among all electrochemical energy storage devices, metal‐air batteries have potential to offer the highest energy density, representing the most promising systems for portable (electronics), mobile (electrical vehicles), and stationary (micro‐grids) applications. To date, however, many fundamental issues are yet to be overcome to realize this potential. For example, efficient catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air‐electrode are yet to be developed to significantly reduce the polarization loss in metal‐air batteries, which severely hinders the rate capability, energy efficiency, and operational life. In this progress report, a brief overview is first presented of the critical issues relevant to air‐electrodes in metal‐air batteries. Some recent advancements in the development of non‐precious catalysts for ORR in Li‐air and Zn‐air batteries are then highlighted, including transition metal oxides, low‐dimensional carbon‐based structures, and other catalysts such as transition‐metal macrocycles and metal nitrides. New directions and future perspectives for metal‐air batteries are also outlined. Non‐precious catalysts for oxygen reduction reactions in the air electrode play a vital role in reducing polarization during cycling and enhancing the performance of metal‐air batteries. Recent developments in non‐precious catalysts for Li‐air and Zn‐air batteries are highlighted.