Aqueous Zinc–Iodine Batteries for Large‐Scale Energy Storage: Challenges, Strategies and Perspectives

Aqueous zinc–iodine (Zn–I 2 ) batteries have emerged as a highly promising new energy storage system, endowed with a high theoretical capacity of 211 mAh g −1 , intrinsic safety, and abundant raw material reserves. However, their practical deployment is severely hampered by critical challenges including the polyiodide shuttle effect, sluggish iodine redox kinetics, zinc dendrite growth, and parasitic side reactions. In this review, we systematically summarize the latest research advances in aqueous zinc–iodine batteries, elaborate on their electrochemical energy storage mechanisms, and dissect the key technical bottlenecks limiting their development. Furthermore, we critically discuss the performance optimization strategies and their underlying reaction mechanisms reported in recent years from the following four core perspectives: the structural design and catalytic modification of cathode materials, interfacial regulation and anode‐free structural innovation of zinc anodes, the introduction of electrolyte additives and modulation of multi‐electron reactions, as well as the functional modification of separators. Finally, we propose the future development directions for this system, aiming to provide theoretical guidance for the design of aqueous Zn–I 2 batteries with high energy density and long cycle life, and to accelerate their large‐scale commercialization.