Aqueous zinc-ion batteries (AZIBs) have emerged as promising candidates for grid-scale energy storage due to their inherent safety, cost-effectiveness, and environmental friendliness. However, the practical application of zinc metal anodes faces significant challenges. The irregular plating/stripping processes readily trigger uncontrollable growth of zinc dendrites, accompanied by side reactions such as the hydrogen evolution reaction and interfacial passivation. These issues lead to reduced Coulombic efficiency, diminished zinc utilization, and shortened cycle life, severely hindering the further development of AZIBs. To address these critical drawbacks, this study reports an in-situ construction of a three-dimensional hierarchical Zn-Sn-Bi ternary alloy protective layer (denoted as Zn-Sn-Bi@Zn) on commercial zinc foil via a controllable chemical etching strategy. The fabrication process involves pre-treatment of the zinc foil, followed by immersion in a specifically formulated chemical etching solution to build a three-dimensional porous scaffold. Subsequently, hydrophilic and zincophilic Sn and Bi metal components are uniformly introduced onto and within the scaffold, forming a robust and conductive composite interface. The incorporated zincophilic Sn and Bi sites can significantly reduce the nucleation overpotential for zinc deposition, guiding the uniform nucleation of Zn²⁺. Furthermore, the unique three-dimensional hierarchical architecture provides abundant active sites and a substantially increased specific surface area. This structure effectively localizes and homogenizes the current density, promoting the even deposition of zinc and thereby physically suppressing dendrite formation. Moreover, the engineered alloy layer exhibits enhanced hydrophilicity and high electrical conductivity, which markedly accelerate interfacial charge transfer kinetics and improve overall reaction dynamics. Comprehensive electrochemical evaluations demon-strate that, benefiting from the multifunctional protection offered by this alloy layer, the Zn-Sn-Bi@Zn symmetric cell achieves an exceptionally stable cycling lifespan exceeding 2800 h under a current density of 0.2 mA•cm⁻² and an areal capacity of 0.2 mAh•cm⁻². After 450 cycles, the Zn-Sn-Bi@Zn half-cell achieves an average Coulombic efficiency as high as 99.7%, showing excellent reversibility of Zn plating/stripping and good corrosion resistance. When paired with a δ-MnO₂ cathode to assemble a full cell, the device delivers a high reversible specific capacity of 156.6 mAh•g⁻¹ after 1600 cycles at a current density of 1 A•g⁻¹. Both the cycling stability and rate capability of this full cell are substantially superior to those of counterparts employing bare zinc anodes.

Key words: aqueous zinc-ion battery, zinc metal anode, ternary alloy, etching, dendrite suppression