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

The layered structures of tungsten disulfide (WS2) and molybdenum tungsten disulfide (MoWS2) are considered as the most promising electrode materials for energy storage devices. Herein, MS (magnetron sputtering) is required for the deposition of WS2 and MoWS2 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 WS2 and MoWS2. CV (cyclic voltammetry), GCD (galvanostatic charging discharging), and EIS (electro-impedance spectroscopy) techniques were employed to analyze the samples. After preparing WS2 with optimized thickness as the superior performing sample, a hybrid device was designed as WS2//AC (activated carbon). With a remarkable cyclic stability of 97% after 3000 continuous cycles, the hybrid supercapacitor generated a maximum energy density (Es) value of 42.5 W h kg-1 and 4250 W kg-1 of power density (Ps). 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 WS2 hybrid device was found to have a hybrid nature. The outstanding outcomes of WS2//AC make it suitable for future energy storage applications.