Facile chemical route for multiwalled carbon nanotube/mercury sulfide nanocomposite: High performance supercapacitive electrode

Supercapacitors as one of the most important energy storage devices have been receiving worldwide attention due to their high capacitance, power density, long cycle life, and rapid charge/discharge rates as compared to conventional electrolytic capacitors and rechargeable batteries. A nanocomposite has been prepared using mercury sulfide (HgS) and multiwalled carbon nanotubes (MWCNTs) via novel, simple, and low-cost ‘dip and dry’ process followed by successive ionic layer adsorption and reaction (SILAR) method. The association of HgS nanoparticles with high surface area reinforced MWCNTs nanonetwork boosts the electrochemical supercapacitive performance of nanocomposite compared to bare HgS and MWCNTs. This nanocomposite yields excellent specific capacitance of 946.43 F/g at scan rate of 2 mV/s and an outstanding rate capability of 93% retention over 4000 cycles with decent charge–discharge cycles. Moreover, the electrode exhibits maximum specific energy and power densities of 42.97 Wh/kg and 1.60 kW/kg, respectively. The promising capabilities of formed nanocomposite can explore the opportunities as alternative electrode material for energy storage applications.