Composite Hydrogels With Controlled Liquid Metal Release for Dendrite‐Free Zinc Anodes

ABSTRACT Rechargeable aqueous zinc‐ion batteries offer a cost‐effective and safe solution for large‐scale energy storage. However, uncontrolled Zn dendrite growth, parasitic hydrogen evolution, and poor Zn plating/stripping reversibility still limit their practical deployment. Herein, a Ga‐In liquid metal‐containing hydrogel electrolyte is designed to stabilize the Zn anode. The controlled release of liquid metal regulates the Zn/electrolyte interfacial environment, promotes preferential Zn deposition along the (103) plane, and alleviates structural embrittlement, thereby improving long‐term interfacial stability. Meanwhile, liquid metal released within the hydrogel facilitates the dissolution of Zn dendrites, reducing the risk of internal short circuits. As a result, Zn symmetric cells using the designed hydrogel electrolyte deliver stable cycling for 6000 h at 1 mA cm −2 and 1 mAh cm −2 . Moreover, Zn || NH 4 + ‐V 2 O 5 full cells operate steadily for over 1750 h at 200 mA g −1 with 85% capacity retention. These results demonstrate that a hydrogel electrolyte with controllable liquid metal release provides an effective strategy for stabilizing Zn anodes in aqueous zinc‐ion batteries.