A HKUST-1 coating with copper metal active site enables stabilized zinc metal anode

Abstract

Aqueous zinc-ion batteries (AZIBs) are considered to be one of the alternatives for large-scale energy storage devices due to unique advantages. However, the harmful Zn dendrites generation of Zn anodes seriously hinders the development of AZIBs. Herein, Cu3(BTC)2 (HKUST-1) as a compact functional interface layer on the surface of bare Zn foil is shown to improve the reversibility of Zn-plating/stripping process. Interestingly, HKUST-1 possesses high porosity, large number of water molecule vacancies, and Cu active center, which help to enhance the diffusion kinetics of Zn2+ and reduce the surface free energy of Zn electrode. Combining theoretical calculations with experiments, the HKUST-1 can contribute to the desolvation process of Zn[(H2O)6]2+ and balance Zn2+ concentration, which thus accelerate Zn2+ transfer kinetics, lower interfacial energy, and homogenize ion-distribution. Attributed to these superiorities, the HKUST-1@Zn symmetric cells demonstrate excellent stable plating/stripping for over 250 h under ultra-high current density (20 mA/cm2 and 20 mAh/cm2). Furthermore, a HKUST-1@Zn||MnO2 full cell exhibits an enhanced long-cycling performance with a discharge capacity of 114 mAh/g after undergoing 500 cycles. All results demonstrate the potential application of HKUST-1 coating in AZIBs.