Abstract

Objective Aqueous zinc-ion batteries （AZIBs） are promising candidates for developing large-scale energy storage systems dueto their inherent safety and non-flammability compared to lithium-ion batteries. However， challenges such as corrosion， hydrogen evolution， and dendrite formation hinder their cycling stability and reversibility. To address these issues， the study developed a three-dimensional （3D） Zn-Sn alloy anode， which demonstrated enhanced corrosion resistance， suppressed hydrogenevolution， and dendrite-free Zn deposition， thereby improving the overall performance of AZIBs.

Methods A 3D Zn-Sn alloy anode was fabricated through a series of steps. Firstly， a 5 mM SnF₂ solution was prepared， and the pretreated Zn foil was immersed in it for 3 min， followed by folding and rolling. After repeating the immersion and rolling process 10 times， the obtained electrode was annealed at 500 ℃ for 3 h in an argon atmosphere to obtain a 3D Zn-Sn alloy anode.

Results and Discussion X-ray diffraction （XRD） analysis confirmed the successful doping of Sn into the Zn matrix. Energydispersive spectroscopy （EDS） revealed a uniform Sn distribution with a mass fraction of 11. 31% in the Zn-Sn alloy anode.Electrochemical tests demonstrated that the Zn-Sn alloy anode exhibited a more positive corrosion potential （-0. 962 V vs.-0. 964 V） and a reduced corrosion current density （3. 89 mA·cm^-2vs. 6. 26 mA·cm^-2

）compared to the pure Zn anode， indicating better corrosion resistance. The hydrogen evolution reaction （HER） potential was reduced from -1. 762 V to -1. 819 V at 10 mA·cm^-2， indicating effective HER suppression. The nucleation and deposition behavior of Zn²⁺on the Zn-Sn alloy anode was investigated using a Zn||Cu half-cell. Cyclic voltammetry （CV） results reveal a significantly lower nucleation overpotential of 41 mV on the Zn-Sn alloy anode compared to 103 mV on the Zn anode， indicating a lower nucleation barrier. The lower barrier facilitated the uniform Zn²⁺deposition and effectively eliminated dendrite formation. Additionally， chronoamperometry（CA）analysis exhibited the advantages of uniform Zn²⁺ deposition at the 3D Zn-Sn alloy anode. It showed that Zn²⁺ on the Zn-Sn alloyanode surface transitioned more rapidly into the 3D diffusion stage， shortening the 2D diffusion process that typically leads to the formation of inhomogeneous zinc nuclei. This mechanism effectively prevented dendrite growth， thereby improving the cycling stability and reversibility of the battery. The symmetric cell with 3D Zn-Sn alloy anode reached a cycle life of 850 h at a currentdensity of 0. 5 mA·cm^-1. The Zn-Sn||Cu half-cell maintained an average coulombic efficiency （CE） of 98% after 900 cycles. Infull-cell configurations， the Zn-Sn||NHVO cell obtained a capacity of 182 mAh·g^-1at 4 A·g^-1 and retained a 47. 2 mAh·g^-1 higher specific capacity than that of the Zn||NHVO cell after 1 000 cycles.

Conclusion In this paper， a 3D Zn-Sn alloy anode was prepared through a series of processes， including replacement， rolling，and annealing. The morphology， electrochemical properties， and cycling stability of the 3D Zn-Sn alloy anode were characterized and analyzed. The results demonstrated that the use of 3D Zn-Sn alloy anodes enhanced the cycle stability and reversibility of symmetric cells， half-cells， and full cells. This work provides a new approach for preparing high-performance alloy anodes，offering a promising solution to improve the anode performance of zinc-ion batteries and produce high-performance AZIBs.

Keywords：aqueous zinc-ion battery； three-dimensional Zn-Sn alloy anode； corrosion resistance； hydrogen evolution suppression； Zn dendrite