Multifunctional Molecular Engineering Enables Simultaneously Dendrite‐Free and Corrosion‐Resistant Zinc‐Halogen Batteries

ABSTRACT The performance enhancement of aqueous zinc‐ion batteries (AZIBs) critically hinges on the intelligent design of electrolyte additives. However, elucidating the complex mechanistic role of additives remains challenging due to intricate multiple interactions at the molecule–electrode interface and within the ion‐solvent structure, rendering traditional trial‐and‐error approaches inadequate for precise performance regulation. To address this, we develop a quantitative model that correlates depth of discharge (DOD) and cycle life. Guided by the correlation between different functional groups, a multifunctional additive featuring both amide (─CONH─) and sulfonic acid (─SO 3 − ) groups was strategically selected. The experimental validation clearly demonstrates that this additive can function through three complementary mechanisms, thereby effectively suppressing the issues of corrosion, hydrogen evolution, and dendrite growth. Consequently, the zinc anode achieves an exceptional cycle reversibility exceeding 5000 h, and Zn||Cu batteries exhibit remarkable stability for 3800 times with a Coulombic efficiency of 99.9%. Notably, this strategy also drastically enhances the cycling stability of both two‐electron and four‐electron Zn||I 2 batteries as well as Zn||Br 2 batteries. This work offers a generalizable, performance‐driven design framework for multifunctional additives, paving the way toward practical, long‐life zinc‐halogen batteries.