Hydrogel Electrolytes for Solvation and Interfacial Regulation in Aqueous Zinc‐Ion Batteries

Hydrogel electrolytes have emerged as promising platforms for stabilizing aqueous zinc‐ion batteries beyond their conventional roles as mechanically confined quasisolid electrolytes. Recent studies increasingly demonstrate that hydrogel‐confined electrochemical environments can dynamically regulate Zn ²⁺ solvation structures, ion‐transport behavior, hydrogen‐bond networks, and interfacial reaction pathways during electrochemical cycling. Such regulation mechanisms substantially influence concentration polarization, Zn nucleation behavior, desolvation kinetics, interfacial side reactions, and Zn deposition stability under repeated plating/stripping conditions. This review comprehensively discusses recent advances in hydrogel electrolytes for aqueous Zn‐ion batteries from the perspective of dynamic ion regulation and interfacial electrochemical stabilization. Particular emphasis is placed on confined water chemistry, polymer‐ion coordination, ion‐flux homogenization, interphase engineering, and electro‐chemo‐mechanical stabilization of dynamically evolving Zn interfaces. In addition, emerging hydrogel architectures together with advanced operando characterization approaches are highlighted to provide future perspectives for developing next‐generation hydrogel electrolytes capable of sustaining highly reversible and durable aqueous Zn electrochemistry.