Mechanically robust cellulose hydrogel electrolyte with ion transport/deposition dual regulation for stable aqueous zinc ion batteries

Hydrogel electrolytes show promise for stabilizing aqueous zinc-ion batteries (AZIBs), but achieving both uniform Zn 2+ transfer and deposition as well as strong mechanical properties remains challenging. Herein, a dual regulation mechanism is established in a mechanically robust hydrogel electrolyte by integrating a cellulose-bentonite network and graphene (Gr) for high-performance AZIBs. Strong hydrogen bond networks between cellulose chains and dense Al-O-C crosslinks formed by the coordination of Al on the bentonite (Bt) surface with cellulose oxygen synergistically enhance the material’s mechanical strength, achieving up to 5.47 MPa. Negatively charged hydroxyl groups within cellulose chains ensure the strong interaction between the hydrogel electrolyte and zinc species, simultaneously inducing Zn (002) deposition due to the low mismatch between (002) Zn and (002) Gr , thus triggering a dual-regulation mechanism to achieve homogeneous Zn 2+ transfer and deposition. This uniquely designed hydrogel electrolyte exhibits a high ionic conductivity of 35.5 mS cm −1 and a large Zn 2+ transference number of 0.72 at room temperature as well as excellent battery performance, including a high Coulombic efficiency of 99.8% over 7000 h of lifespan, and superior electrochemical stability. This work offers a promising hydrogel electrolyte to promote the utilization of stable AZIBs. • Strong hydrogen-bond networks and dense Al-O-C crosslinks synergistically impart excellent mechanical strength without compromising ionic conductivity. • The Cbt/Gr electrolyte exhibits exceptional specific strength (5.47 MPa) and high ionic conductivity (35.5 mS cm −1 ). • It demonstrates a high CE of 99.8%, an extended lifespan exceeding 7000 h, and superior electrochemical stability.