Interfacial Engineering via Halide Anion Derived Specific Adsorption Toward Regulated Deposition Kinetics for Zn Metal Anodes.

Aqueous rechargeable zinc-ion batteries are attractive for large-scale energy storage but suffer from concurrent dendritic Zn growth and water-induced parasitic reactions at the Zn/electrolyte interface. To address the intrinsic instability of interfacial layers formed by conventional, weak-interaction-based additive engineering, a specific-adsorption-dominated strategy is proposed to stabilize Zn anodes. Driven by interactions between surface Zn atoms and anionic lone pairs, halide anions form short-range surface bonds with partial charge transfer to Zn atoms, yielding a partially covalent Zn-halide chemisorbed layer within the inner Helmholtz plane. In contrast to the nonspecific and weakly adsorbed layers, such a chemisorbed layer possesses enhanced cohesive strength and resistance against perturbation, enabling long-term interfacial protection. The resulting interphase lowers the Zn²⁺ desolvation barrier to enhance interfacial kinetics while constructing a water-deficient interface that suppresses hydrogen evolution. Consequently, Zn//Zn symmetric cells with halide-containing electrolyte operate stably for > 4900 h at 1.0 mA cm⁻²/1.0 mAh cm⁻² with a cumulative plating capacity of 2.45 Ah cm⁻², while Zn//Cu cells deliver an average Coulombic efficiency (CE) of 99.7%. When paired with a NaV₃O₈·1.5H₂O (NVO) cathode, full cells further demonstrate improved rate capability and prolonged cycling, confirming that halide-anion chemisorption is a robust and generalizable strategy for highly reversible Zn anodes.