Molecular Gating of the Reactive Water Topological Network for Stable Aqueous Zn Batteries.

Abstract

The instability of aqueous Zn batteries originates not only from the intrinsic reactivity of water, but also from the continuous hydrogen-bonded network that enables cooperative interfacial degradation. In conventional aqueous electrolytes, this percolated water network supports proton relay, hydrogen evolution reaction (HER), local alkalization, by-product precipitation, and Zn2+ flux distortion, thereby forming a self-amplifying failure loop at the Zn/electrolyte interface. Herein, we propose a molecular gating strategy to regulate this reactive water network using 4-hydroxy-2-butanone (HBN) as a dual-site hydrogen-bond modulator. The carbonyl and hydroxyl groups of HBN competitively interact with water, fragmenting the continuous H2O-H2O hydrogen-bond network into low-cooperativity water domains and suppressing proton-relay HER. Concurrently, HBN mildly reshapes the Zn2+ solvation sheath environment toward a less water-dominated configuration, moderating interfacial charge‑transfer while preserving essential Zn2+ transport. This topology-gated aqueous regime simultaneously suppresses water-induced side reactions, prevents alkaline passivation-driven Zn2+ flux distortion, and enables compact Zn deposition. Consequently, the optimized electrolyte affords highly reversible Zn plating/stripping with an average Coulombic efficiency of 99.12% over 800 cycles and supports a 1.0 Ah-level NVO||Zn pouch cell for 70 cycles with negligible capacity decay.