Unlocking High‐Performance Four‐Electron Zinc‐Iodine Batteries through Halogen Bonding Inversion and Non‐Identical‐Frequency Molecular Vibrations

Abstract

Abstract The activation of four‐electron transfer behavior through I − /I 0 /I + conversion reactions is crucial for the development of high‐energy‐density zinc–iodine batteries (ZIBs) but is hindered by the rapid hydrolysis of I + in protic solvents. Theoretically, the directionality and modifiability of halogen bonds (XBs) can be used to regulate the hydrolytic disproportionation of I + . Given that the conventional coordination configuration is not applicable because of the locking of the XB donor (I + ), the inversion of the coordination configuration to establish a charge distribution preanisotropy (σ‐holes) and thus realize XB‐stabilizing electron‐scale coordination is vital for breaking down the barriers existing in protic solvents. To counteract external environmental disturbances, the cohesive energy differentiation based on the Hansen parameter creates the non‐identical‐frequency molecular vibrations of additives with water. Herein, an electrolyte additive (chloroacetonitrile, ClAN) with these advantages enabled the redox coupling of I − /I 0 /I + at a very low salt concentration (4 molar kg −1 ). The corresponding ZIB exhibited a specific discharge capacity of 175.7 mA h g −1 after 4000 cycles at 2 A g −1 and showed an extremely high specific capacity at high rates (133.1 mA h g −1 at 50 A g −1 ). This work establishes a generalized framework and new horizons for halogen batteries with multiple electron transfers.