Modifying the Zn Anode with Nano-Silica: A Strategy to Realize Dendrite-Free Zinc-Ion Hybrid Supercapacitors

Abstract

In recent years, zinc-ion hybrid supercapacitors have been widely studied due to many advantages, but zinc dendrite and anodic corrosion limit its cycle stability and safety performances. A hybrid coating composed of nano-silica and polyvinylidene fluoride was prepared on the surface of metal zinc by coating method. Insulating nano-silica is conducive to the directional migration of Zn2+, and hydrophobic coating can effectively reduce anodic corrosion. The Zn@SiO2//Zn@SiO2 symmetrical cell exhibits stable cycling for over 500 cycles at 1 mA cm−2, while the bare Zn symmetrical cell shows high overpotential and short cycle life. The specific capacity of the assembled zinc ion hybrid supercapacitor under different current densities is higher than that of bare zinc cell. When the current density is 0.2 A g−1, the specific capacity reaches 263.1 mAh g−1. This study reveals a simple and effective strategy to achieve dendrite-free zinc anode.