Adsorption‐Mediated Reconstruction of the Interfacial Water Microenvironment Balances Parasitic‐Reaction Suppression and Zn ²⁺ Transport for Stable Aqueous Zn Metal Anodes

ABSTRACT

Regulating the adsorption‐defined electric‐double‐layer (EDL) microenvironment at Zn anodes is an effective strategy to suppress parasitic reactions and dendrite growth in aqueous zinc‐ion batteries. However, the benefits of such regulation depend on maintaining an appropriate interfacial balance, because excessive depletion of interfacial H ₂ O and overly dense compact‐layer coverage can hinder Zn ²⁺ interfacial transfer/(re)solvation during Zn stripping, resulting in sluggish dissolution and poor reversibility. Herein, we introduce an ultralow‐dose, non‐sacrificial interfacial regulation strategy by adding 0.1 m

N‐octyl‐D‐glucamine (NODG) into a ZnSO ₄ ‐based electrolyte. Theoretical calculations and experimental results show that NODG preferentially adsorbs on Zn and reconstructs the adsorption‐defined EDL microenvironment, thereby moderately depleting interfacial H ₂ O, lowering local water activity, and suppressing hydrogen evolution and other water‐driven side reactions, while still preserving sufficient Zn ²⁺ (re)solvation kinetics during stripping. As a result, the uniformity and reversibility of Zn plating/stripping are markedly improved, enabling stable Zn||Zn symmetric‐cell cycling for over 2300 h at 1.0 mA cm ⁻² /1.0 mAh cm ⁻² and an average Coulombic efficiency of 99.10% for Zn||Cu cells over 450 cycles. This work highlights the importance of maintaining an appropriate adsorption‐mediated interfacial balance and provides a simple, scalable electrolyte‐additive strategy for long‐life aqueous zinc‐ion batteries.