Entanglement Added to Cross‐Linked Chains Enables Tough Gelatin‐Based Hydrogel for Zn Metal Batteries

Abstract Currently, it is still challenging to develop a hydrogel electrolyte matrix that can successfully achieve a harmonious combination of mechanical strength, ionic conductivity, and interfacial adaptability. Herein, a multi‐networked hydrogel electrolyte with a high entanglement effect based on gelatin/oxidized dextran/methacrylic anhydride, denoted as ODGelMA is constructed. Attribute to the Schiff base network formulation of ─RC═N─, oxidized dextran integrated gelatin chains induce a dense hydrophilic conformation group. Furthermore, addition of methacrylic anhydride through a grafting process, the entangled hydrogel achieves impressive mechanical features (6.8 MPa tensile strength) and high ionic conductivity (3.68 mS cm −1 at 20 °C). The ODGelMA electrolyte regulates the zinc electrode by circumventing dendrite growth, and showcases an adaptable framework reservoir to accelerate the Zn 2+ desolvation process. Benefiting from the entanglement effect, the Zn anode achieves an outstanding average Coulombic efficiency (CE) of 99.8% over 500 cycles and cycling stability of 900 h at 5 mA cm −2 and 2.5 mAh cm −2 . The Zn||I 2 full cell yields an ultra‐long cycling stability of 10 000 cycles with a capacity retention of 92.4% at 5 C. Furthermore, a 60 mAh single‐layer pouch cell maintains a stable work of 350 cycles.