Chemical surface tuning of zinc metal anode toward stable, dendrite-less aqueous zinc-ion batteries

The commercialization of Zn batteries is confronted with urgent challenges in the metal anode, such as dendrite formation, capacity loss, and cracking or dissolution. Here, surface interfacial engineering of the Zn anode is introduced for achieving safety and dendritic-free cycling for high-performance aqueous Zn batteries through a simple but highly effective chemical etching-substitution method. The chemical modification induces a rough peak-valley surface with a thin fluorine-rich interfacial layer on the Zn anode surface, which regulates the growth orientation via guiding uniform Zn plating/stripping, significantly enhances accessibility to aqueous electrolytes and improves wettability by reducing surface energy. As a result, such a synergetic surface effect enables uniform Zn plating/stripping with low polarization of 29 mV at a current density of 0.5 mA cm−2 with stable cyclic performance up to 1000 h. Further, a full cell composed of a fluorine-substituted Zn anode coupled with a β-MnO2 or Ba-V6O13 cathode demonstrates improved capacity retention to 1000 cycles compared to the pristine-Zn cells. The proposed valley deposition model provides the practical direction of surface-modified interfacial chemistries for improving the electrochemical properties of multivalent metal anodes via surface tuning.