A low-cost and non-corrosive electropolishing strategy for long-life zinc metal anode in rechargeable aqueous battery

Rechargeable aqueous zinc (Zn) batteries have attracted great interests because of its inherent safety and cost-effectiveness. However, the uncontrollable Zn dendrite formation in aqueous electrolyte restricts its reversibility for long-life application. The bulge or passivation layer in pristine Zn surface serves as nuclei for large amount of Zn crystal aggregation and inhomogeneous Zn electrodeposition. Here, for the first time, we demonstrate a simple, effective, and non-corrosive electropolishing strategy to develop a smooth and clean Zn metal as compared with burdensome and unreliable mechanical polishing method in lab-scale research. After removing the primitive passivation layer, the fresh Zn anode can survive at a high current density of 40 mA cm−2 over 6000 times. Moreover, the electropolished Zn gains more consistent and reliable electrochemical behaviors which contributes to study the mechanism of Zn electrodeposition and clarify the effectiveness of protective strategies in the follow research.