Transition metal dichalcogenide electrodes with interface engineering for high-performance hybrid supercapacitors

Transition metal dichalcogenides (TMDCs) have been explored in recent years to utilize in electronics due to their remarkable properties. This study reports the enhanced energy storage performance of tungsten disulfide (WS₂) by introducing the conductive interfacial layer of Ag between the substrate and active material (WS₂). The interfacial layers and WS₂ were deposited through a binder free method of magnetron sputtering and three different prepared samples (WS₂ and Ag-WS₂) were scrutinize via electrochemical measurements. A hybrid supercapacitor was fabricated using Ag-WS₂ and activated carbon (AC) since Ag-WS₂ was observed to be the most proficient of all three samples. The Ag-WS₂//AC devices have attained a specific capacity (Q_s) of 224 C g^-1, while delivering the maximum specific energy (E_s) and specific power (P_s) of 50 W h kg^-1 and 4003 W kg^-1, respectively. The device was found to be stable enough as it retains 89% capacity and 97% coulombic efficiency after 1000 cycles. Additionally, the capacitive and diffusive currents were obtained through Dunn's model to observe the underlying charging phenomenon at each scan rate.