Bio‐Inspired Bidirectional Proton Regulatory Mechanisms by Anhydride‐Based Hydrogel Electrolytes for High‐Performance Aqueous Zinc‐Ion Batteries

ABSTRACT Aqueous zinc‐ion batteries (AZIBs) employing hydrogel electrolytes offer significant advantages in mitigating short‐circuit and electrolyte leakage risks. Nevertheless, the sluggish transport kinetics of Zn 2 + and severe interfacial instability of zinc anodes still severely restrict their further development. Herein, a bio‐inspired hydrogel electrolyte based on poly(acrylamide‐co‐maleic anhydride) (P(AM‐co‐MA)) copolymer is fabricated to construct a dual‐functional polymer network. The dynamic acid–base equilibrium between carboxyl and amide groups enables reversible bidirectional proton buffering, which effectively suppresses the hydrogen evolution reaction and anode corrosion. Meanwhile, the synergistic Zn 2 + hopping sites constituted of carboxylate and amide groups optimize the ion‐transport microenvironment and accelerate Zn 2 + migration kinetics synchronously, realizing the coordinated regulation of proton activity and Zn 2 + transport. Thus, the optimized P(AM‐co‐MA) hydrogel electrolyte delivers a high Zn 2 + transference number of 0.66 and an ionic conductivity of 16 mS cm −1 . The assembled Zn||Zn symmetric cells achieve ultra‐long and stable cycling for over 2700 h at 1 mA cm −1 . Furthermore, the pouch‐type Zn||NaV 3 O 8 full cells based on this hydrogel electrolyte exhibit a high specific capacity of 254 mAh g −1 at 1 A g −1 , with a capacity retention of 80% after 120 cycles, verifying the great application potential of this rational design for flexible energy storage devices.