Tailoring the interfacial surfaces of tungsten and molybdenum tungsten disulfide electrodes for hybrid supercapacitors.

The layered structures of tungsten disulfide (WS 2 ) and molybdenum tungsten disulfide (MoWS 2 ) are considered as the most promising electrode materials for energy storage devices. Herein, MS (magnetron sputtering) is required for the deposition of WS 2 and MoWS 2 on the surface of the current collector to attain an optimized layer thickness. The structural morphology and topological behavior of the sputtered material were examined via X-ray diffraction and atomic force microscopy. Three-electrode assembly was used to start the electrochemical investigations to identify the most optimal and effective sample among WS 2 and MoWS 2 . CV (cyclic voltammetry), GCD (galvanostatic charging discharging), and EIS (electro-impedance spectroscopy) techniques were employed to analyze the samples. After preparing WS 2 with optimized thickness as the superior performing sample, a hybrid device was designed as WS 2 //AC (activated carbon). With a remarkable cyclic stability of 97% after 3000 continuous cycles, the hybrid supercapacitor generated a maximum energy density ( E s ) value of 42.5 W h kg -1 and 4250 W kg -1 of power density ( P s ). Besides, the capacitive and diffusive contribution during the charge-discharge process and b -values were calculated by Dunn's model, which lay in the 0.5-1.0 range and the fabricated WS 2 hybrid device was found to have a hybrid nature. The outstanding outcomes of WS 2 //AC make it suitable for future energy storage applications.