Sulfonate‐Modified Covalent Organic Framework Integrated Hydrogel Electrolyte: Enhancing AZIBs Performances by Tailoring Microstructures and Functional Groups

Abstract Aqueous zinc‐ion batteries (AZIBs) are emerging as sustainable energy storage systems, yet their practical application is challenged by issues such as dendrite growth and hydrogen evolution. A critical factor in enhancing the performance of AZIBs is the development of hydrogel electrolytes (HEs) which offer reduced free water, thereby mitigating side reactions and preventing leakage. However, achieving a balance between reduced free water and maintaining high ionic conductivity is challenging. Herein, a sulfonate‐modified covalent organic framework (COF‐BSO 3 Zn) is designed via the facile method and intergated it into polyacrylamide (PAM) to form PAM/COF‐BSO 3 Zn (PAM/CBZn) HEs. The COF‐BSO 3 Zn exhibits enhanced aqueous dispersibility and significantly improved adsorption capacity for Zn 2+ . The PAM/CBZn hydrogel electrolyte possesses ultrahigh ionic conductivity (64.43 mS cm −1 ) and excellent Zn 2+ transference number (0.84) due to the ordered porous structure of COF‐BSO3 Zn within hydrogel, which provides channels for efficient Zn 2+ transport. Besides, the sulfonate groups can regulate the solvation structure, contributing to uniform deposition and inhibiting side reactions. Electrochemical tests demonstrate stable cycling over 1800 h with minimal polarization in symmetrical cells. This work innovatively highlights a new direction of tailoring microstructures and functional groups in HEs to enhance the performance of AZIBs, showing great potential toward next‐generation energy storage systems.