Interfacial electronic insulation strategy for high-performance Zinc-ion batteries

Abstract

Aqueous rechargeable zinc metal batteries have garnered widespread attention due to their inherent high safety, high volumetric capacity, and low cost. However, the uncontrollable growth of zinc dendrites and severe hydrogen evolution reaction (HER) side reactions lead to low Coulombic efficiency and short lifespan of zinc metal anodes, hindering their practical application. We employed a plasma fluorination strategy to in-situ react on the surface of zinc metal to generate an electron-insulating ZnF₂ coating, which reduces HER, suppresses dendrite growth, and enhances the wettability of the electrode with the electrolyte. Through density functional theory (DFT) and molecular dynamics (MD) simulations, we systematically studied the mechanism by which ZnF₂ improves interfacial properties, suppresses the hydrogen evolution reaction (HER), and inhibits dendrite formation. Ultimately, symmetric batteries and Zn@ZnF₂||Cu batteries assembled with Zn@ZnF₂ electrodes exhibited significantly extended cycle life and high Coulombic efficiency. Full cells of Zn@ZnF₂||MnO₂@CNT achieved a cycle life of over 5000 cycles at a current density of 1 A g⁻¹. This study provides a practical method for industrial treatment of the Zn surface and offers an in-depth analysis and discussion of the role of ZnF₂ in inhibiting dendrite growth, HER, and improving interfacial wettability in zinc-ion batteries.