Fluorine‐Driven Electrolyte Engineering: Regulating Zn ²⁺ Coordination and Electrode‐Electrolyte Interfacial Chemistry in Aqueous Zinc Ion Batteries

Abstract Electrolyte additives that simultaneously regulate Zn 2+ solvation and induce robust solid electrolyte interphase (SEI) formation offer an effective approach to suppress dendrite growth, hydrogen evolution, and side reactions in aqueous zinc‐ion batteries (AZIBs). Here, fluorinated acetylacetone derivatives are employed to achieve these dual functions at low concentrations. Progressive fluorination enhances electron delocalization and lowers the lowest unoccupied molecular orbital (LUMO), enabling preferential accumulation at the Zn surface. Specifically, hexafluoroacetylacetone (HFAT) forms stable [Zn(H 2 O) 5 HFAT] 2+ solvation shells, reducing interfacial water activity and promoting Zn 2+ desolvation. The lowest LUMO of HFAT further enables its preferential electrochemical reduction, leading to the formation of a gradient cement‐brick‐like ZnF 2 ‐rich SEI that stabilizes Zn deposition and enhances Zn 2+ transport. As a result, Zn||Zn symmetric cells exhibit lifespans exceeding 4300 h at 1 mA cm −2 /1 mAh cm −2 , Zn||Cu cells achieve an average Coulombic efficiency of 99.62% over 1500 cycles, and Zn||I 2 full cells retain 125.8 mAh g −1 after 10 000 cycles. This study highlights the potential of fluorine‐driven electrolyte design to synergistically optimize solvation structure and interfacial stability for high‐performance AZIBs.