Restricting Two‐Electron Oxygen Reduction via Secondary Coordinated Sulfur Enabling Ultralong‐Lifespan Zn‐Air Batteries

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.