Abstract: The progress of zinc (Zn) metal batteries (ZMBs) is greatly limited by poor cycling stability because ofthe mutual restrictions of dendrite growth, corrosion reactions, and passivation. In this work, an ultra-long lifespan (∼7800 h), dendrite-free Zn metal anode is enabled via fabricating a functional hydrogel electrolyte out of polyacrylamide/graphene oxide (GO)/agarose (PGA) with a multifully cross-linked net-work. The synergetic integration of GO nanosheets and double-network structure endows the PGA hy-drogel electrolyte with high ionic conductivity and excellent mechanical performance. More importantly,the abundant hydrophilic groups and stable three-dimensional cross-linked network of PGA electrolyteeffectively constrain Zn²⁺ diffusion laterally along the Zn surface, which simultaneously prohibits water-induced corrosion and thus significantly enhances Zn anode reversibility. Both theoretical simulations andexperiments reveal that the PGA electrolyte is capable of optimizing de-solvation kinetics and harmoniz-ing Zn²⁺ flux at the electrolyte-electrode interface, ensuring uniform Zn²⁺ deposition. Consequently, an ultra-long lifespan of 7800 h is achieved in the symmetric cell with the PGA electrolyte. Even at a high Znutilization of 42.7 %, it still delivers stable cycling over 1100 h. This work provides a practical and benefi-cial approach to dramatically extending the lifespan of the Zn anode and thus achieving high-performanceZMBs.

Key words: Zinc metal anode, Hydrogel electrolyte, Graphene oxide, Double-network structure, Ultra-long lifespan