Dual‐Function High‐Entropy Alloy Nanocatalysts Enable Long‐Life Aqueous Zinc–Iodine Batteries

Abstract Aqueous zinc–iodine (Zn–I 2 ) batteries are considered a promising sustainable energy storage system due to their high energy density, cost‐effectiveness, and environmental friendliness. However, polyiodide shuttling leads to severe capacity loss and poor cycle stability. Herein, FeCoNiCrMn high‐entropy alloy (HEA) nanocatalysts are introduced, leveraging their inherent multi‐elemental synergy and abundant active sites for both exceptional polyiodide adsorption and accelerated redox kinetics. As a result, the Zn–I 2 batteries with HEA nanocatalysts deliver a remarkable specific capacity of 220.23 mAh g −1 at 1 A g −1 (≈100% iodine utilization) and exhibit minimal capacity decay (0.0014% per cycle) over 25 000 cycles at 5 A g −1 . Furthermore, Zn–I 2 pouch cells (5×5 cm 2 , 7.5 mg cm −2 iodine loading) with HEA catalysts enable high capacity retention (17.0 mAh after 2000 cycles at 4 mA cm −2 ). This work demonstrates the high‐entropy catalysis as a powerful strategy for designing high‐performance, durable Zn–I 2 batteries.