Multi‐Site High‐Entropy Immobilizer for All‐Iodine Species Fixation in High‐Performance Zinc‐Iodine Batteries

Abstract Zinc‐iodine (Zn‐I 2 ) batteries are of great interest thanks to their high energy density, low cost, and inherent safety. However, the dissolution of I − and the generated polyiodides exacerbated by the dissolved I − severely reduces the utilization of the active substance, resulting in poor coulombic efficiency and a drastic decrease in performance. In this regard, chemical immobilization of iodine species with high‐entropy material is developed. Benefiting from the remarkable catalytic and anchoring activity of the high‐entropy material, accelerated catalytic conversion and chemisorption of polyiodides are realized. Meanwhile, the distribution characteristics of the multi‐active adsorption centers on the high‐entropy material enable the abundant active sites to anchor the highly soluble and hard‐to‐mobilize I − in a chemical bonding manner. Such a unique bonding mode allows all iodine species (I 2 /I − /I 3 − ) to be firmly immobilized on the electrode, which enhances the effectiveness and utilization of rechargeable Zn‐I 2 batteries. High‐entropy material with the ability to immobilize all species of iodine provides a novel/effective strategy for realizing high‐performance Zn‐I 2 batteries.