Long-cycling Zinc Metal Anodes Enabled by an In Situ Constructed ZnO Coating Layer

Suppressing dendrite growth in zinc (Zn) anodes for aqueous Zn batteries remains a significant challenge. Modifying the Zn/electrolyte interface stands out as one of the most promising strategies to tackle this problem. In this study, a nanometer-thick ZnO coating layer with a uniform concave surface geometry is in situ constructed to modify the Zn anode for the first time. The chemical bond formed between the ZnO layer and the Zn foil enhances the structural stability of the synthesized ZnO modified-Zn anode. Finite element simulations indicate that the ZnO coating layer facilitates uniform electric field distribution and zinc flux on the Zn electrode. In situ optical observations unveil how the modification interface regulates zinc plating behaviors on the Zn anode. Impressively, the symmetrical ZnO-Zn cell displays a remarkable cycling stability of 1765 h at a current density of 5 mA cm-2 with an areal capacity of 1 mAh cm-2. Even when subjected to a very high current density of 50 mA cm-2, it maintains stable operation over 3800 cycles. This success highlights the immense application potential of the rationally tailored ZnO-Zn anode. A nanometer-thick ZnO coating layer is in situ constructed on Zn foil to regulate Zn electrodeposition for the first time. As a result, the symmetrical ZnO-Zn cell displays remarkable cycling stability of 1765 h at 5 mA cm-2 with 1 mAh cm-2. Finite element simulations and in situ optical observations reveal the modification mechanism.image