Design Strategies and Advanced Methods for Cathode Engineering in Aqueous Zinc-Iodine Batteries

Aqueous zinc-iodine batteries (AZIBs) have attracted increasing attention as a safe, cost-effective, and sustainable energy storage solution. As the key component determining capacity and energy density, the iodine cathode faces persistent challenges, including polyiodide shuttling, high-valence iodine species hydrolysis, sluggish redox kinetics, and poor multi-electron utilization. Recent research efforts have focused on rational design of iodine cathodes to enhance iodine species confinement, promote reversible multi-electron redox reactions, and improve reaction kinetics. This review systematically summarizes recent advances of iodine cathode design strategies in two-electron and multi-electron AZIBs, emphasizing material structures, interaction mechanisms, and their roles in improving reaction kinetics. Finally, perspectives are offered on future opportunities to guide the development of high-performance, long-life AZIBs.