Inhibiting Proton Corrosion and Hydrogen Evolution Reaction on the Surface of Zinc Anodes by Hierarchical Structure Hydrogel to Realize Long‐Life Aqueous Zinc Metal Batteries

Abstract Aqueous zinc metal batteries possess a high theoretical capacity and inherent safety. However, the corrosion of the zinc anode and hydrogen evolution reactions impairs their practical performance, leading to unsatisfactory capacity and limited lifespan. Herein, hierarchical structure hydrogels with lean‐water and rich‐water characteristics are designed to address these challenges. The lean‐water hydrogel on the anode side effectively mitigates the proton corrosion of the zinc anode and suppresses the hydrogen evolution reaction. The anchoring effect and desolvation of zwitterions on the lean‐water hydrogels facilitate the deposition of zinc ions. Meanwhile, the rich‐water hydrogels on the cathode side provide abundant intercalation ions for high‐capacity energy storage. Benefit from the synergistic effect of dual functions, the electrochemical stability window of the hierarchical structure hydrogel is enhanced to 2.35 V, which is applied to various aqueous energy storage devices. Zn||Zn symmetrical battery exhibits stable cycling performance for 1200 h at a depth of discharge of 80%. The Zn||VN full battery achieves a capacity retention rate of 91.2% after 4000 cycles at a current density of 2 A g −1 . The hierarchical structure of hydrogels with excellent cycling stability offers a promising strategy for long‐life aqueous zinc metal batteries.