Chemical Passivation Stabilizes Zn Anode

Aqueous zinc ion batteries are an attractive option for grid-scale energy storage, which is vital to the integration of renewable energy resources with the electric energy infrastructure. The cycling stability of aqueous ZIBs is determined by the electrochemical reversibility of Zn anode, which is often deteriorated by its corrosion and dendritic Zn deposition. Here, a simple and rapid surface passivation strategy that can drastically improve the cycling stability of Zn anodes is demonstrated. For example, a dip in KMnO4 solution readily forms a continuous, conformal, and robust protective layer on the native Zn surface, leading to a more uniform plating/stripping process, increased corrosion resistance, and tolerance to manufacturing and processing defects on Zn metal electrodes. The Zn electrode cycling stabilities at 1 mA cm-2 and 1 mA h cm-2 are extended by ≈40 times. In full battery tests in the configuration of Zn||β-MnO2 , the full cell with passivated Zn anode exhibited a capacity retention of 68.7% after 300 cycles at a current density of 1.0 A g-1 , while the cell with untreated Zn anode can only retain 7.4% of capacity under the same conditions.