Design of High-Performance Symmetric Supercapacitor Based on WSe2 Nanoflakes for Energy Storage Applications

Recently, transition metal dichalcogenides (TMDCs) have emerged as promising candidates as electrode materials for energy storage applications due to their remarkable physio-chemical properties. In the present work, a highly pure and crystalline tungsten diselenide (WSe2) thin-film-based supercapacitive electrode has been successfully synthesized on a graphite substrate by using the DC magnetron sputtering method. Comprehensive characterization techniques including X-ray diffraction (XRD), Raman spectroscopy, Field emission-scanning electron microscopy (FE-SEM), and X-ray photoelectron spectroscopy (XPS) were employed to confirm the phase, elemental bonding, surface morphology, and chemical composition of the fabricated thin-film electrode, respectively. The sputtered WSe2 thin-film electrode demonstrates an impressive increase in areal capacitance of almost 7.7 times when compared to the bare graphite substrate, with a measurement of 149.75 mF cm(-2). The electrode demonstrated excellent cyclic stability, retaining 86.15% of its capacitance even after 2000 cycles, showing the long-term usability and high potential of WSe2 as an electrode. The capacitive performance of this symmetric supercapacitor device was carried out by using WSe2 as a cathode as well as the anode with the 1 M Na2SO4 electrolyte. Standing out in terms of electrochemical performance, the present symmetric supercapacitor executed a higher areal energy density and power density of 5.54 mWh cm(-2) and 1197 mW cm(-2), respectively. This WSe2@graphite thin-film-based supercapacitive electrode with its superior electrochemical performance is believed to pave the way for the development of reliable and effective energy storage systems.