Stable and dendrite-free Zn anode with artificial desolvation interface layer toward high-performance Zn-ion capacitor

Abstract

Aqueous Zn-based energy storage devices possess tremendous advantages, such as low cost, high safety, and competitive energy density, due to employing a Zn metal anode and aqueous electrolyte. However, the cycling stability and rate ability of a Zn anode are hindered by Zn dendrite growth and sluggish ion transfer in the electrode/electrolyte interface. Herein, the interfacial properties of Zn anodes are improved through the introduction of a silver (Ag) protective layer, which facilitates uniform Zn deposition and regulates Zn ion transport. As a result, Ag-coated Zn anodes display stable cycling performance (600 h at 1 mA cm−2) and low overpotential (150 mV at 50 mA cm−2 after 2000 cycles). The Ag layer in situ electrochemically converts into an AgZn3 layer and promotes Zn ion desolvation and three-dimensional diffusion processes. Moreover, a Zn-ion capacitor assembled with an Ag-coated Zn anode and active carbon cathode shows a capable cycling lifespan and rate performance. This study provides a feasible strategy for constructing a stabilized and dendrite-free Zn anode for the development of high-performance Zn-based energy storage devices.