Microenvironment modulation of W single‐atom catalyst by ionic liquid for enhanced oxygen reduction in zinc‐air battery

Abstract Tungsten single‐atom (WNC) catalysts deliver promising oxygen reduction reaction (ORR) activity for zinc‐air batteries (ZABs). However, poor surface microenvironment suppresses ORR activity, thus deteriorating the performance of the assembled ZABs. Herein, the surface of tungsten single‐atom catalyst was modified with fluorine‐containing ionic liquids (IL‐WNC). Ionic liquids boost WNC hydrophilicity via hydrogen bonding, tune its electronic structure by electrostatic interactions to accelerate charge transfer and optimize intermediate adsorption, and form a protective layer for enhanced stability. Owing to such favorable synergistic interactions, the IL‐WNC exhibits a half‐wave potential of 0.87 V for ORR. When the IL‐WNC is used as the cathode to assemble a ZAB, the ZAB demonstrates a power density of 220.1 mW cm −2 , a specific capacity of 796.1 mA h g −1 , and a cycle stability of 630 h. The ionic liquid modification is promising for tuning surface microenvironment to boost catalyst activity and stability toward high‐performance ZABs.