CoSe2/WSe2/rGO anode for high-performance energy storage device applications

Abstract

Herein, we conducted electrochemical studies on WSe₂, CoSe₂, and CoSe₂/WSe₂/rGO nanocomposite for designing high-performance and durable energy storage device. The synthesized materials were characterized using X-ray diffraction (XRD), scanning and transmission electron microscopy, Raman spectroscopy, and Brunauer–Emmett–Teller (BET) surface area measurements. Electrochemical performance of the synthesized electrode materials was systematically studied using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements. The specific capacitance (SC) of the CoSe₂/WSe₂/rGO electrode (1756 F g⁻¹ at 2.6 A g⁻¹) was found to be significantly high than that of the pure WSe₂ (752 F g⁻¹ at 2.6 A g⁻¹) and CoSe₂ (698 F g⁻¹ at 2.6 A g⁻¹) electrodes. The enhanced surface area of the CoSe₂/WSe₂/rGO electrode causes to improve its charge storage performance. It is worth mentioning that the addition of CoSe₂ and rGO to WSe₂ (CoSe₂/WSe₂/rGO) improve- the charge storage performance of the WSe₂ by more than two times with relatively better cycling stability (93%) than that of CoSe₂ (85%) and WSe₂ (80%) after 3000 cycles. An asymmetric supercapacitor (ASC) CoSe₂/WSe₂/rGO//AC device showed an energy density of 64 W h kg⁻¹ at a power density of 2234 W kg⁻¹ with good cycling stability. The charged CoSe₂/WSe₂/rGO//AC device successfully powered a light-emitting diode (LED) for 20 min after charging the device for 30 s.