Multiphase Cu-Zn alloys interlayer enabled by in-situ electrochemical preparation in deep eutectic solvents for ultra-stable zinc metal anode of Zn-ion battery

Zn alloy engineering has emerged as a promising anodic strategy for aqueous Zn-ion batteries (AZIBs), effectively suppressing side reactions and dendritic growth. However, the impact of multiphase alloy compositions on zinc deposition and overall battery stability remains insufficiently understood. In this study, a versatile deep eutectic solvent (DES) was employed as both the electrolyte and the reaction medium for multiphase alloy formation. Hierarchically porous Cu-Zn multiphase alloys were fabricated on a three-dimensional (3D) Cu foam substrate (Cu-Zn/CF) via electrochemical deposition, with precise control over alloy composition achieved by adjusting deposition parameters. The synergistic interactions among Cu-Zn alloying elements significantly enhance the hydrogen evolution overpotential, reduce corrosion current, and effectively suppress Zn dendrite formation during repeated cycling. Furthermore, the combination of Cu-Zn alloys with the 3D Cu foam architecture facilitates highly reversible zinc plating and stripping processes. Consequently, the Cu-Zn/CF anode demonstrates exceptional cycling stability, maintaining performance for over 4000 h at 0.5 mA·cm −2 (0.5 mAh·cm −2 ). Notably, the anode retains excellent cycling stability with minimal polarization and an average Coulombic efficiency of 99% even under rigorous operating conditions. This work not only clarifies the functional roles of alloying components but also presents a novel strategy for the development of stable, dendrite-free zinc metal anodes.