Sieve-Like interface built by ZnO porous sheets towards stable zinc anodes

Abstract

Zn-based electrochemical energy storage (EES) systems are plagued by the uncontrollable generation of dendritic zinc and side reactions on zinc anodes. Herein, we report a ZnO porous sheets-assembled sieve-like interface to stabilize zinc anodes. Specifically, ZnO porous sheets are synthesized through the thermal decomposition of basic zinc sulfate nanoflakes and then served as an artificial zinc anode-electrolyte interface. Benefiting from the sieve-like interface formed by the ZnO porous sheets, Zn2+ flux is effectively homogenized during the zinc plating process and thus zinc dendrite growth is restricted. Meanwhile, the corrosion behavior of zinc anodes is alleviated thanks to the hydrophobic feature of the ZnO porous sheets. As a result, the electrochemical properties of zinc anodes are notably optimized under the protection of such a sieve-like interface. Cycling life evaluated at 1 mA cm−2 of the zinc anodes is prolonged from less than 100 h for bare zinc anodes to 2800 h for the protected zinc anodes (Zn@ZnO), and even at 5 mA cm−2, the latter ones can operate normally for 400 h. As expected, the cycling life of VO2//Zn@ZnO zinc-ion batteries is greatly increased, achieving 90% capacity retention after 1000 cycles at 5 A g−1 and activated carbon fiber//Zn@ZnO zinc-ion hybrid supercapacitors possess 96% capacity retention after 10,000 cycles at 1 A g−1. This work provides a promising approach for improving the electrochemical stability of the Zn-based EES system.