Formation of H <sub>2</sub> O <sub>2</sub> in Near‐Neutral Zn‐air Batteries Enables Efficient Oxygen Evolution Reaction
Roman R. Kapaev, Nicole Leifer, Alagar Raja Kottaichamy, Amit Ohayon, Langyuan Wu, Menny Shalom, Malachi Noked
Abstract
Abstract Rechargeable Zn‐air batteries (ZABs) with near‐neutral electrolytes hold promise as cheap, safe and sustainable devices, but they suffer from slow charge kinetics and remain poorly studied. Here we reveal a charge storage mechanism of near‐neutral Zn‐air batteries that is mediated by formation of dissolved hydrogen peroxide upon cell discharge and its oxidation upon charge. This H 2 O 2 ‐mediated pathway facilitates oxygen evolution reaction (OER) at ~1.5 V vs. Zn 2+ /Zn, reducing charge overpotentials by ~0.2–0.5 V and mitigating carbon corrosion—a common issue in ZABs. The manifestation of this mechanism strongly depends on the electrolyte composition and positive electrode material, contributing up to ~60 % of the capacity with ZnSO 4 solutions and carbon nanotubes. Enhancing the H 2 O 2 ‐mediated pathway offers a route to higher energy efficiency and durability in near‐neutral ZABs, advancing practical, sustainable energy storage.