Optimization of transition metal sulfide through sputtered transition metal nitride thin film for hybrid supercapacitors

Energy storage devices are an immediate requisite to reduce our reliance on fossil fuels and mitigate the environmental impact of traditional energy sources. Hybrid supercapacitors (HSCs) sprung up as the most promising solution while catering to the battery's low power density and SC's low energy density. In this regard, transition metal dichalcogenides (TMDCs) based 2D layered materials are widely explored. Here we see how the performance of the WS2 is affected by introducing a conductive interfacial layer through sputtering entitled titanium nitride (TiN), with a thickness of 100 nm between the substrate and active electrode material. WS2 and TiN-WS2 electrodes were tested for electrochemical performance by employing cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in half and full cell respectively. The specific capacity (Qs) of a TiN-WS2 hybrid device is 329 C/g (465 F/g), with energy density (Es) and power density (Ps) of 77 Wh/kg and 4250 W/kg, respectively. The device's 91.40 % capacity retention vindicates the enhancement of the WS2 characteristics and its stability via interfacial properties. The linear model is also used to elucidate the capacitive and diffusive charge storage in comparison to the Quadratic model for device at different scan rates.