Promising Hydrogel Electrolytes for Aqueous Rechargeable Zinc-Iodine Batteries: A Concept

Rechargeable zinc-iodine batteries (RZIBs) have garnered significant attention owing to their distinct superiorities of low cost, high safety, and high theoretical capacity. However, their large-scale implementation is hindered by several critical challenges, including the polyiodide shuttle effect, uncontrolled Zn dendrite growth, interfacial corrosion issues, and pronounced self-discharge. This review systematically summarizes hydrogel electrolyte-based strategies, with the objectives of suppressing the polyiodide shuttle effect, promoting uniform Zn deposition, enhancing environmental adaptability, facilitating multi-electron iodide conversion, and enabling flexible applications. These efforts are expected to advance the development of high-performance, long-lifespan RZIBs toward practical utilization.