Anion-induced facet-selective etching of Zn metal anode for long cycle aqueous Zn-ion batteries

Constructing (002) crystal plane-exposed Zn anodes by acid etching strategy can efficiently inhibit the Zn dendrite growth in aqueous zinc-ion batteries. However, there is rare research on the role of anions in the etching process. Herein, we investigate the effects of anions in acid etching strategies by theoretical calculations and experimental analyses. The strong adsorption of anions (such as C6H5O73− and C6H6O72−) on Zn (002) plane can prevent acid etching. Therefore, the electrode with exposed Zn (002) plane (CA@Zn) is successfully prepared by citric acid etching. Due to the exposed Zn (002) plane and a unique porous architecture, the CA@Zn displays high corrosion resistance, excellent Zn reaction kinetics, and dendrite suppression. As a result, the CA@Zn symmetric cell exhibits a stable cycling for 1600 h at a current density of 0.5 mA cm−2 and the CA@Zn||Cu half cell achieves a high average Coulombic efficiency of 98.2 % for 1200 cycles. Moreover, CA@Zn||MnOOH full cells deliver high specific discharge capacity and excellent rate performance.