Engineering isolated precious-metal-free site for air cathode in zinc-air batteries

Abstract

Rechargeable zinc–air batteries (ZABs) are now appealing increasing attention for energy storage, due to their low manufacturing cost and ultrahigh specific energy storage. However, the industrial applications of ZABs are limited by the sluggish kinetics of oxygen electrocatalytic reactions at air cathode, namely oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Single-atom catalysts (SACs), with isolated metal sites, particularly for non-precious metal (NPM) have emerged as promising candidates for ZABs, offering high electrocatalytic performance, nearly 100% atom utilization efficiency, and superb electrochemical durability. Herein, recent breakthroughs in the fabrication of NPM SACs for ZABs are systematically summarized, with a special view towards enhancing ZABs performance. Also, the special emphasis on the relationships between the coordination structure of the SAC and its electrocatalytic performance is also placed, followed by a comprehensive discussion about the challenges and opportunities of NPM SACs in practical ZABs.