Fabrication zinc oxide nanotubular arrays on the surface of zinc‑bismuth alloy for high-performance aqueous zinc-ion battery anodes

In this work, zinc oxide (ZnO) nanotubular arrays were fabricated on the surface of zinc‑bismuth (Znbi) alloys with different bismuth contents (0.5, 1, 1.5, and 2 wt%) using an anodization technique. The influence of bismuth content on the morphology of the ZnO nanotubular arrays was explored. By optimizing anodization parameters in an electrolyte containing 50 mM sodium bicarbonate, ethylene glycol, and volume ratio of water to ethylene glycol is 9:1. ZnO nanotubular arrays with uniform nanotubular diameters (395.2 ± 53.6 nm) were synthesized on the zinc surface. The increasing of content of bismuth reduced the average nanotubular diameter from 487.2 ± 54.2 nm for ZnO (Zn-0.5Bi) to 293.4 ± 26.5 nm for ZnO (Zn2Bi). When used as an anode, the anodized Znbi alloy demonstrated good cycling stability in aqueous zinc-ion battery, maintaining a capacity of 95.04 mAh g⁻¹ after 1000 cycles at 1 a g⁻¹. The anodized Znbi electrode also exhibited excellent cycling stability in a symmetric cell, with an overpotential of only 28.5 mV at 1 mA cm⁻². This work provides a promising protocol for designing highly stable zinc-based anodes