Artificial solid electrolyte interface layer based on sodium titanate hollow microspheres assembled by nanotubes to stabilize zinc metal electrodes

Abstract

Recently, aqueous zinc-ion batteries with intrinsic safety, low cost, and environmental benignity have attracted tremendous research interest. However, zinc dendrites, harmful side reactions, and zinc metal corrosion stand in the way. Herein, we use lepidocrocite-type sodium titanate hollow microspheres assembled by nanotubes to constitute an artificial solid electrolyte interface layer on the zinc metal electrode. Thanks to the hierarchical structure with abundant open voids, negative-charged layered framework, low hydrophilicity, electrically insulting nature, and large ionic conductivity, the sodium titanate coating layer can effectively homogenize the electric field, promote the Zn2+ ion transfer, guide the Zn2+ ion flux, reduce the desolvation barrier, improve the exchange current density, and accommodate the plated zinc metal. Consequently, this coating layer can effectively suppress zinc dendrites and other unfavorable effects. With this coating layer, the Zn//Zn symmetric cell is able to provide an impressive cumulative zinc plating capacity of 1375 mAh cm−2 at a current density of 5 mA cm−2. This coating layer also contributes to significantly improved electrochemical performances of Zn//MnO2 battery and zinc-ion hybrid capacitor. This work offers new insights into the modifications of zinc metal electrodes.