Restricting Two‐Electron Oxygen Reduction via Secondary Coordinated Sulfur Enabling Ultralong‐Lifespan Zn‐Air Batteries
Wenxian Liu, Jinxiu Feng, Henan Wang, Pu Wang, Dong Zheng, Wenhui Shi, Fangfang Wu, Tianqi Deng, Xiehong Cao
Abstract
Abstract The direct four‐electron oxygen reduction reaction (4e − ORR) critically governs efficiency and lifespan in metal–air batteries and fuel cells, yet selectively suppressing competitive 2e − and stepwise 2e − pathways that generate corrosive hydrogen peroxide remains a major challenge. Herein, we demonstrate the strategic incorporation of secondary coordinated sulfur atoms into transition metal‐N‐C electrocatalysts to effectively promote direct 4e − ORR and simultaneously suppress undesirable 2e − pathways. Density functional theory (DFT) calculations and operando spectroscopy reveal that enhanced adsorption of key intermediate *OOH facilitates efficient O─O bond cleavage, underpinning altered catalytic selectivity. Importantly, this approach is universally applicable to various carbon‐based catalysts, including Co─N@C, Ni─N@C, Mn─N@C, and N@C. Specifically, a sulfur‐mediated Co─N/Co@C catalyst, comprising Co─N 4 sites and Co nanoparticles, dramatically lowers the 2e − O 2 ‐to‐H 2 O 2 rate constant to merely 0.05‐fold of its original value at 0.78 V. Consequently, Zn‐air batteries using Co─N/Co@C‐S as cathode exhibits an outstanding peak power density of 220 mW cm −2 , remarkable lifespan over 2500 h, and outstanding rate performance from 5 to 50 mA cm −2 . This work paves a generalizable route for designing highly active and selective electrocatalysts suitable for advanced long‐life energy storage devices.