Stable Zn anode enabled by a hydrophobic–zincophilic bifunctional interface

Aqueous Zn-ion batteries are promising next-generation energy storage systems owing to their inherent safety. However, the challenges including “dead Zn” accumulation, low depth of discharge (DOD), and severe side reactions impede their wide development. To address these issues, herein, a hydrophobic–zincophilic Cu(OTf)₂ layer is anchored on Cu foil through strong coordination adsorption. Cu(OTf)₂ can suppress aqueous side reactions via hydrophobic C–F groups and provide nucleation sites for uniform Zn deposition by the electrostatic interaction of sulfonic acid group with Zn²⁺. A precisely pre-deposited Zn anode (Zn@Cu-OTf) is fabricated via controlled electrodeposition, which reduces excess Zn consumption and enhances the performance at higher DODs. Consequently, the Zn@Cu-OTf symmetric cell maintains stable cycling for 724 h at 2 mA·cm⁻² with 40% DOD. Cu-OTf||Zn half-cell achieves homogeneous Zn deposition/stripping, with a Coulombic efficiency of 99.7% over 1400 cycles. Moreover, the Zn@Cu-OTf||MnO₂ full cell retains 69.4% of its initial capacity after 500 cycles at 1 A·g⁻¹ and demonstrates outstanding rate capability. This study validates the effectiveness of hydrophobic–zincophilic interface layer in improving the reversibility and durability of Zn anodes.