Molecular‐Anion Interfacial Engineering for Solid Electrolyte Interphase to Obtain High‐Performance Aqueous Zinc‐Ion Batteries

ABSTRACT

Uncontrolled Zn dendrite growth and parasitic interfacial reactions severely undermine the long‐term cyclability of aqueous zinc‐ion batteries (AZIBs). Herein, an organic‐inorganic hybrid multicomponent solid electrolyte interphase (SEI) was constructed on the Zn anode via interfacial engineering, by introducing citric acid (CA) and Zn(OTf) ₂ into baseline ZnSO ₄ electrolyte. CA preferentially adsorbs and decomposes in the inner Helmholtz layer (IHL) to form a gradient organic outer layer, whereas OTf ⁻ and SO ₄ ²⁻ are reduced and deposited to generate a multicomponent inorganic inner layer (ZnF ₂ , ZnO, ZnS). This hybrid SEI stabilizes the Zn/electrolyte interface, suppresses corrosion, accelerates interfacial kinetics, and guides uniform Zn ²⁺ deposition. Consequently, Zn||Cu cells deliver 99.9% average Coulombic efficiency (CE) over 5500 cycles at 5 mA cm ⁻² , 1 mAh cm ⁻² ; Zn||Zn symmetric cells cycle stably for over 2438 h at 10 mA cm ⁻² , 1 mAh cm ⁻² ; Zn||MnO ₂ full cells with 149 mAh g ⁻¹ initial capacity retain 88% capacity after 1414 cycles at 1 A g ⁻¹ . This work provides an effective strategy to robust interphases for high‐performance durable AZIBs.