Interhalogen Complexation Suppresses Hydrolysis–Corrosion Cross‐Talk Degradation in Aqueous Two‐Electron Zn–I 2 Batteries

ABSTRACT Aqueous two‐electron Zn–I 2 (I ‒ /I 0 /I + ) batteries offer high theoretical energy density; however, their practical operation is limited by hydrolysis of iodine monochloride (ICl), which induces cathode irreversibility and Zn‐anode degradation. Here, we introduce an ether‐based complexation strategy that stabilizes interhalogen species and mitigates cross‐talk degradation in aqueous two‐electron Zn–I 2 batteries. Density functional theory calculations and spectroscopic analyses reveal the selective formation of an ICl–15‐crown‐5 (15C5) complex among various linear and cyclic ethers. The electron‐deficient iodine center in ICl is coordinated by electron‐rich oxygen atoms in 15C5 through lone‐pair donor–acceptor interactions. In situ UV–vis spectroscopy, distribution of relaxation times analysis, intrinsic reaction coordinate calculations, and real‐time pH monitoring collective…