Development of Durable Zn–MnO 2 Battery via a Functionalized Hydrogel Film

Abstract Aqueous zinc (Zn) battery with remarkable advantages of high safety, low cost, and high reversibility is highly applauded in next‐generation low‐speed electric vehicles and large‐scale energy storage applications. However, Zn anode suffers from a series of unfavorable reactions, hindering its progress toward industrialization. Herein, a functionalized hydrogel film is designed using polydopamine and polyacrylamide crosslinking (PDAM) as the Zn protective layer to stabilize the Zn anode. Benefiting from the strong interaction of Zn 2+ with PDAM, the primary solvation shell of Zn 2+ is regulated by PDAM into the form of PDAM–Zn 2+ ‐5H 2 O. This remodeling prevents Zn dendrite growth and inhibits water‐induced side reactions. As a result, the Zn–MnO 2 battery using PDAM‐coated Zn anode exhibits excellent cycling stability, demonstrating over 1150 cycles at an areal capacity of 5 mAh cm −2 with an average Coulombic efficiency (CE) of 96.5%. For a scaled‐up PDAM@Zn–MnO 2 pouch cell with a capacity of 80 mAh, stable cycling of over 200 cycles with an average CE of 91.9% is achieved. The superior Zn–MnO 2 battery enabled by the functionalized hydrogel protective film enlightens an arena toward next‐generation energy storage applications.