WS2/Carbon Composites and Nanoporous Carbon Structures Derived from Zeolitic Imidazole Framework for Asymmetrical Supercapacitors

Transition metal dichalcogenides (TMDs) are generating immense research interest in the field of supercapacitors owing to their 2D morphology and other existing material properties. Nonetheless, more research efforts are needed to address their low conductivity and relatively poor cycle stability. In the present work, an asymmetrical supercapacitor (ASC) is assembled using a WS2/carbon composite as a positive electrode and nanoporous carbon (NPC) (derived from zeolitic imidazolate framework (ZIF-8)) as a negative electrode. In the presence of 1 M H2SO4 aqueous electrolyte, the above ASC has yielded excellent electrochemical performance due to the efficient combination of the feature of redox active WS2 nanorods and highly conductive NPC. In individual studies, the WS2/Z8-800 (positive) and Z8-800 (negative) electrodes have delivered specific capacitances of 248.7 and 437.6 F/g, respectively. The full ASC has been charged-balanced to fabricate a 1.4 V device, which has delivered an energy density of 25 Wh/kg upon discharging at a power rate of 801 W/kg. The study should also open up future opportunities to explore other sulfide based TMDs in conjugation with nanoporous carbon for the development of advanced supercapacitors.