Ultrathin VS2 nanoplate with in-plane and out-of-plane defects for an electrochemical supercapacitor with ultrahigh specific capacitance

Abstract

2D TMDs represented by MoS₂ have been examined extensively due to their large specific surface area and special physical or chemical characters which facilitate exposure of the active sites and shortening of the diffusion pathway of the electrolyte ion. Here, an ultrathin VS₂ TMD nanoplate with in-plane and out-of-plane defects prepared by a simple colloidal chemical synthesis method is reported. The existence of nanopores and atomic distortion or disarrangement in the basal plane and the break of the crystal lattice in the side edge have been investigated in detail. These rich-defect nanoplates exhibit ultrahigh specific capacitance (2200 F g⁻¹ at a current density of 1 A g⁻¹) in a three electrode system as anode materials of an electrochemical supercapacitor. Moreover, the fabricated asymmetric supercapacitor achieved excellent energy density (66.54 W h kg⁻¹ at a power density of 0.75 kW kg⁻¹) and long-life cycling (5000). This performance is superior to other asymmetric supercapacitors based on vanadium, nickel, cobalt oxides/hydroxides or sulfides. We believe this electrode material could be a proper candidate for the next generation of portable supercapacitors based on practical evaluation by lighting an LED panel.