Glycerol‐Regulated Cytocompatible, Self‐Healing Gel Electrolyte Stabilizes Zinc Metal Anodes for Quasi‐Solid‐State Aqueous Batteries

ABSTRACT Aqueous zinc batteries are attractive for safe and sustainable energy storage, but their practical development is strongly limited by the instability of Zn metal in water‐containing electrolytes, which promotes corrosion, parasitic reactions, nonuniform ion transport, and dendritic deposition. Here, we develop a glycerol‐regulated cytocompatible, self‐healing gel electrolyte (SHGE) based on a poly(vinyl alcohol)/poly(ethylene glycol) matrix. Glycerol reorganizes the hydrogen‐bonding environment and reduces polymer crystallinity, thereby decreasing water reactivity while enhancing polymer‐chain mobility and ionic transport. The resulting gel also modifies the Zn 2+ coordination environment and promotes more regulated interfacial ion transfer, suppressing Zn corrosion and enabling compact and homogeneous Zn deposition. Consequently, Zn||Zn symmetric cells sustain stable plating/stripping for over 3300 h at 5 mA cm − 2 and 5 mAh cm − 2 . The SHGE further exhibits low in vitro cytotoxicity toward multiple cell types, together with good flexibility and self‐healing capability. As a proof of concept for quasi‐solid‐state full‐cell operation, trace thiourea is introduced to promote sulfur redox conversion in Zn–S cells, enabling reversible cycling with high Coulombic efficiency and durable pouch‐cell operation. These results establish a multifunctional gel‐electrolyte strategy for stabilizing Zn metal anodes while integrating mechanical adaptability and cytocompatibility in quasi‐solid‐state aqueous batteries.