Superhydrophobic SiO2 coating layer enabling stable and reversible Zn anode for aqueous Zn-ion batteries

Aqueous Zn-ion batteries (ZIBs) have great potential for the next-generation energy storage devices, however, its development has been plagued by uncontrolled growth of zinc dendrites and corrosion. To uniformize Zn2+ flux and prevent H2O invasion is of great importance. Herein, we construct an artificial interface layer on Zn anode with superhydrophobic SiO2 (SiO2-Zn) possessing abundant Zn2+ pathway and stable hydrophobicity, thus, SiO2-Zn present stable stripping/plating during long-term cycling process. As such, the SiO2-Zn||SiO2-Zn symmetrical cell operates over 1500 h for 0.1 mA h cm−2 at 0.1 mA cm−2 (only 148 h for bare Zn), over 1200 h for 2 mA h cm−2 and 4 mA cm−2, much better than bare Zn||Zn cell. The SiO2-Zn||SiO2-Cu half-cell achieves a high coulombic efficiency of 99.8 % over 360 cycles. The SiO2-Zn||MnO2 full cell exhibits a capacity of 158.6 mAh g−1 and a retention of 91.3 % after 300 cycles, as well as excellent rate performance.