Chemically synthesized copper sulfide nanoflakes on reduced graphene oxide for asymmetric supercapacitors

The present work describes the deposition of coppersulfide (Cu₂S) nanoflakes onto reduced graphene oxide (rGO) on three dimensional (3D) nickel foam byinexpensive chemical methods. The nanohybrid structure exhibitedexcellent surface area (41.67 m² g⁻¹) with a porous structure (pore size 22.8 nm) and good electrical conductivity with a maximum specific capacitance of 1264 F g⁻¹ at a scan rate of 5 mV s⁻¹. The Cu₂S@rGOcomposite exhibits a significantlyhigher specific capacitance. The nanohybrid structure showed outstandingcycling stability of 94 % after 10000cycles. The asymmetric supercapacitor (ASC) device, Cu₂S@rGO//rGO exhibited a maximumspecific capacitance of 135 F g⁻¹ withhighenergy and power densities of 50 Wh kg⁻¹, and 7000 W kg⁻¹, respectively.