Electrolyte Design Toward High-Performance Zinc-Iodine Batteries: Progress, Challenges, and Prospects

Aqueous rechargeable zinc-iodine (Zn-I₂) batteries have emerged as a promising energy storage solution, offering benefits such as affordability, high energy density, and enhanced safety. However, challenges like the thermodynamic instability of the iodine cathode and undesirable interfacial reactions at the zinc anode lead to issues such as slow redox kinetics, multiple iodide shuttles, and zinc dendrites. This paper reviews the basic working principles of Zn-I₂ batteries, describes the scientific problems within the iodine conversion and zinc stripping-plating processes, and details specific strategies to solve the Zn-I₂ battery problems with a focus on the electrolyte optimization. In view of the fact that aqueous Zn-I₂ batteries are still in their infancy, the review aims to provide insights for optimizing their design and advancing their real-world applications.