Zincophilic 3D ZnOHF nanowire arrays with ordered and continuous Zn2+ Ion modulation layer enable long-term stable Zn metal anodes

Abstract

Metallic Zn anode is a key component for aqueous rechargeable Zn-ion batteries (ZIBs) owing to its high theoretical capacity, low cost, and excellent safety. However, the practical applications remain impeded by dendritic growth and side reactions occurring at the Zn anode surface. Herein, a 3D ZnOHF nanowire array interface is for the first time in-situ built on Zn foil (ZnOHF NWs@Zn) through a hydrothermal method, and then used as an ordered and continuous Zn2+ ion modulation layer to guide the reversible and long-cycling Zn plating/stripping processes. As demonstrated by our density functional theory (DFT) calculations, the ZnOHF shows the desired superior zincophilic properties compared to pure Zn, enabling a low Zn nucleation energy and a fast Zn2+ ion diffusion. Moreover, the 3D ZnOHF NW architecture homogenizes the electric field distribution, thus modifying the subsequent Zn deposition process. Consequently, the thus-obtained ZnOHF NWs@Zn anode demonstrates a low Zn nucleation overpotential (87.8 at 5 mA cm−2), high Zn storage capacity (72.8 mAh cm−2) and excellent coulombic efficiency (exceeding 98.8%). The effectiveness of the ZnOHF NWs@Zn anode is also demonstrated through ZnOHF NWs@Zn//ZnOHF NWs@Zn symmetrical cell and MnO2@CC//ZnOHF NWs@Zn ZIB full cell, both with outstanding cycle stability.