Enabled Uniform Zn Stripping/Plating by Natural Halloysite Nanotube Coating with Opposite Charge for Aqueous Zn-Ion Batteries

Because aqueous Zn-ion batteries have good eye-catching merits, such as cost-effectiveness and high safety, which have been considered one of the most hopeful energy storage devices. However, owing to the uncontrollable dendrite growth and serious corrosion in mild electrolytes, the limited lifespan of the Zn metal anodes seriously affected their industrial applications. Herein, the aforementioned problems can be addressed by coating natural halloysite nanotubes (HNTs) on the Zn foil (HNTs@Zn) and then enhancing Zn reversibility. The negative charge on the surface of HNTs could make the charge distribution on the surface of the metal Zn uniform and inhibit dendrite growth underneath the artificial layer. Moreover, due to the positive charge in the HNT tube, the possibility of byproduct formation could be reduced by selectively adsorbing SO3CF3– inside of the HNTs. Accordingly, the HNTs@Zn electrode exhibits a low voltage hysteresis (16 mV) and a long cycle life (over 2000 h at 0.2 mA cm–2) in a symmetrical cell test. Such advantages bring high reversibility to full Zn batteries with V2O5 cathodes, which deliver high capacity retention (∼82.0%) after 3000 cycles at 5 A g–1. The optimized Zn anode provides an attractive strategy for the development of high-performance aqueous Zn-ion batteries.