Thermally Healable Electrolyte‐Electrode Interface for Sustainable Quasi‐Solid Zinc‐ion Batteries

Abstract Quasi‐solid zinc‐ion batteries using hydrogel electrolytes show great potential in energy storage devices owing to their intrinsic safety, fewer side reactions and wide electrochemical windows. However, the dendrite issues on the zinc anodes cannot be fundamentally eliminated and the intrinsic anode‐electrolyte interfacial interspace is rarely investigated. Here, we design a dynamically healable gelatin‐based hydrogel electrolyte with a highly reversible sol‐gel transition, which can construct a conformal electrode‐electrolyte interface and further evolve into a stable solid‐solid interface by in situ solidification. The unique helical gelatin chain structure provides a uniform channel for zinc ion transport by the bridging effect of sulfate groups. As a consequence, the dynamically healable interface enables dendrite‐free zinc anodes and repeatedly repairs the anode‐electrolyte interfacial interspaces by the reversible sol‐gel transition of gelatin electrolyte to retain long‐lasting protection for sustainable zinc‐ion batteries.