One-step superficial electrodeposition of nickel-cobalt-sulfide for high-energy hybrid asymmetric supercapacitor

A cathodic electrodeposition (ED) technique is adopted to grow multi-component nickel–cobalt-sulfide (NCS) nanosheet arrays on highly conducting nickel foam substrate. The chronoamperometry (CA) deposited electrode has shown exceptional electrochemical activity in terms of specific capacity, rate capability and excellent redox reversibility than the cyclic voltammetry (CV) deposited electrode. Having the benefit of highly conductive nanosheet arrays and three-dimensional open framework of the nanostructure, the binary metal sulfide exhibits high specific capacity of 820 C g−1 at 2 A g−1. When the NCS electrodes were combined with boron-doped graphene oxide to form an asymmetric hybrid supercapacitor, it delivered a high energy density of 83 Wh g−1 and high-power density of 9619 W kg−1.