Cathode‐Hydrogel Electrolyte Interaction in Aqueous Zinc‐Ion Batteries: Degradation Mechanism and Optimization Strategies

Abstract Aqueous zinc‐ion batteries (AZIBs) have demonstrated promising prospects due to their high safety, low cost, and environmental friendliness. However, their development has been constrained by liquid electrolyte‐induced issues such as zinc dendrite growth, cathode material dissolution, and electrolyte leakage. Hydrogel electrolytes, which combine the benefits of both liquid and solid electrolytes, have effectively mitigated these challenges and have emerged as a research hotspot. Hydrogel electrolytes have beneficial effects on AZIBs’ cathodes, especially in aspects such as reducing material dissolution and structural damage caused by liquid electrolytes, as well as poor interfacial contact in solid‐state electrolytes (SSEs). This review systematically investigates the challenges faced by common cathode materials in conventional liquid electrolytes. The critical role of cathode‐hydrogel electrolyte interaction (CHEI) in enhancing cathode performance is summarized and discussed in detail by focusing on cathode electrolyte interfaces (CEI). Comprehensive strategies tailored to hydrogel electrolytes for various cathode materials are summarized, including optimization of ion transport dynamics, physical confinement, and regulation of redox reactions. Finally, material design strategies for hydrogel electrolytes are proposed based on the CHEI, along with their development prospects.