The ZnO-SiO2 Composite Phase with Dual Regulation Function Enables Uniform Zn2+ Flux and Fast Zinc Deposition Kinetics Toward Zinc Metal Batteries

As an important candidate for rechargeable energy storage devices, the large-scale development of aqueous zinc ion batteries has been hindered by hydrogen evolution and uncontrollable dendrites of metal anodes. A novel ZnO-SiO2 composite interface phase (Zn@ZSCP) with a double protective effect based on in situ synthesis by hydrothermal method is used to improve these difficulties. The hydrophilic SiO2 layer is beneficial to the dissolution of hydrated zinc ions and reduces the nucleation barrier during zinc deposition, while the stable ZnO layer helps to adjust the electric field distribution on the surface of the metal anode to further induce uniform zinc nucleation. The cycle life of the Zn@ZSCP||Zn@ZSCP symmetric battery based on this innovative interface phase modification is up to 2500 h. Even at a high current density of 8 mA cm-2, the symmetric battery still has a stable cycle life of more than 2000 h. The zinc-iodine full battery based on Zn@ZSCP anode and low-cost biomass-derived porous carbon exhibits an excellent specific capacity and outstanding cycle stability. This simple and reasonable battery structure design not only improves the practicability of aqueous zinc ion batteries to a certain extent but also helps to develop more efficient and environmentally friendly zinc metal batteries.