All‐MXene Co‐Design Enables Fast Iodine Redox and Ultrastable Zinc Anode in Aqueous Zn–I ₂ Batteries

ABSTRACT Aqueous zinc–iodine (Zn–I ₂ ) batteries combine intrinsic safety with low cost and attractive energy density, but progress is limited by polyiodide shuttling at the cathode and unstable zinc deposition at the anode, which together drive self‐discharge and poor cycle life. Herein, an all‐MXene synergistic strategy is proposed that co‐engineers both electrodes using fluorine‐rich MXenes (i.e., Nb ₂ C‐F and V ₂ C‐F) synthesized via HF vapor etching. The Nb ₂ C‐F serves as the iodine host with its expanded galleries, and fluoride nanodomains immobilize polyiodides and catalyze the I ⁻ /I ₂ conversion, suppressing the shuttle effect and accelerating kinetics. Meanwhile, the V ₂ C‐F forms a fluoride‐rich substrate that homogenizes Zn ²⁺ flux and nucleation and promotes an in situ inorganic hybrid SEI interwoven with ZnF ₂ network and ZnS/‐SO ₃ components, thereby enabling uniform and stable zinc deposition. The Zn–I ₂ full cell, leveraging the coordination of Nb ₂ C‐F@I ₂ cathode and V ₂ C‐F@Zn anode, delivers a high capacity of 220.7 mAh g ⁻¹ at 0.2 A g ⁻¹ , maintains 105.8 mAh g ⁻¹ at 5 A g ⁻¹ , alongside an exceptional cycling stability of 72.8% capacity retention over 60 000 cycles, with a Coulombic efficiency approaching 100%. This work establishes an All‐MXene synergistic strategy in which co‐design of the iodine host and zinc interface enables durable, high‐rate aqueous Zn‐I ₂ batteries.