Approaching 100% Comprehensive Utilization Rate of Ultra‐Stable Zn Metal Anodes by Constructing Chitosan‐Based Homologous Gel/Solid Synergistic Interface

Abstract Aqueous Zn–metal batteries are considered promising candidates for next‐generation energy storage. However, low zinc utilization rate (ZUR) and limited cycle life are still hinder its commercial application because of severe parasitic side effects. Herein, inspired by the wound healing process, an innovative electrode recovery technology is developed to improve the comprehensive ZUR and prolong the cycling life through repetitive rejuvenation of zinc anode by designing chitosan‐based homologous gel/solid synergistic electrolyte. The designed synergistic electrolyte, consisting of protonated chitosan gel electrolyte and Zn‐chitosan solid electrolyte, exhibits superior zinc ion diffusion capability and low free‐water activity, leading to dendrite‐free Zn deposition and HER inhibition. Moreover, through proton neutralization and zinc ion complexation, the formulated electrolyte can implement the rejuvenation of zinc anode by smoothing interfacial defects and eliminating parasitic byproducts. Consequently, the gel/solid synergistic electrolyte displays reversible Zn plating/stripping chemistry for 4000 cycles with high average Coulombic efficiency (99.8%) and realizes comprehensive ZUR of 97.4% through four iterations of electrode recover under extreme conditions (20 mA cm⁻², 31.5% Zn depth of discharge), noticeably higher than zinc electrode with no recover (11.8%). Furthermore, the superiority of customized synergistic electrolyte is further demonstrated by coupling with I₂ cathode and achieving impressive 36 000 stable cycles.