Uniform SEI design via Solvent Competitions for Stable Anode‐Free Zinc Batteries

Abstract Solid electrolyte interphase (SEI) with high uniformness is one of the essential approaches to improving the electrochemical performance of anode‐free zinc metal batteries. However, nonuniform solvation concentration and distribution at the interface lead to random SEI nucleation and uncontrolled growth, resulting in a low‐quality SEI morphology that thereby compromising the calendar life of the batteries. Herein, a uniform SEI is constructed through a strongly solvent‐weakly solvent competition strategy. The underlying evolution mechanism is elucidated that electron‐withdrawing oxygen of the weakly solvent with the amino hydrogen of dimethoxyethylamine competing manipulation driven a structural transition from ring‐serrated configurations to expanded linear architectures. This forms high‐density, anion‐aggregated solvation clusters at the substrate interface, enabling uniform nucleation and 2D growth of SEI. The optimized SEI facilitates spatially homogeneous Zn‐ion flux, thereby obtaining highly ordered Zn deposition and avoiding dendrites, minimizing the accumulated consumption of active zinc during long cycling. The Zn||VO 2 ‐V 2 O 5 /NC cells achieve 13,000 stable cycles with limited zinc. The anode‐free zinc cells deliver exceptional cycle ability of 500 cycles with 99.82% average coulombic efficiency.