Facile synthesis of layered 2H-WSe2 nanosheets for asymmetric supercapacitor device application

Abstract

Herein, controlled and large-scale WSe2 nanosheets were synthesized by a simple one-step solvothermal method and the synthesized material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy (RS), and X-ray photoelectron spectroscopy (XPS) measurements. The (002) plane confirms the presence of 2H-WSe2 phase. The electrode of 2H-WSe2 shows specific capacitance (SC) of 618.75 F/g at 3.3 A/g in 3 M KOH electrolyte with optimal cycling stability and retention ability. Furthermore, an asymmetric solid-state supercapacitor (WSe2//AC) is fabricated with WSe2 as positive electrode and activated carbon (AC) as a negative electrode. The device delivers an energy density of 25.5 Wh/kg at power density 1111 W/kg and retains stability of 77 % at 5 A/g current density for 10,000 cycles. Thus, WSe2 may be used as active electrode material for developing sustainable energy storage devices.