A Focused Review on Zinc‐Anode Protection for Durable Aqueous Zinc–Iodine Soft‐Gel Electrode Batteries

ABSTRACT Aqueous zinc–iodine batteries offer a safe and low‐cost storage option, but their durability is limited by coupled zinc‐anode degradation and iodine‐species crossover. Soft‐gel iodine cathodes can improve iodine retention through confinement and molecular interactions, yet mobile iodine/polyiodide intermediates may still reach zinc. The anode is concurrently vulnerable to heterogeneous plating/stripping, hydrogen evolution, corrosion, passivation, and dead‐zinc formation; these processes are further intensified by iodine‐derived oxidants, causing self‐discharge and active‐material loss. This review examines zinc‐anode protection in aqueous zinc–iodine soft‐gel electrode batteries. It discusses interfacial failure modes, fundamental protection principles, and strategies based on substrate engineering, artificial interphases, structural designs, separator‐assisted regulation, and electrolyte modification. Emphasis is placed on iodine/polyiodide compatibility and coordinated design of the zinc anode, electrolyte, separator, and soft‐gel cathode. Durable operation requires simultaneous control of zinc reversibility, water activity, polyiodide crossover, and redox‐state‐compatible iodine retention.