Fabrication of hierarchical NiCo2S4@GO nano-sponge electrode: as advanced electrode for supercapacitor applications

NiCo 2 S 4 is a promising material for use in supercapacitors due to its high conductivity and redox activity. However, its cycling stability is poor due to the structural degradation of the electrode caused by the redox reaction. NiCo 2 S 4 is encased with an ultrathin graphene oxide layer to produce a core/shell structure (NiCo 2 S 4 @GO). We present a simple approach for the fabrication of NiCo2S4/graphene composites. With a specific capacitance of 1100 F g −1 and a current density of 1 A g −1 , the NiCo 2 S 4 @GO composite demonstrates exceptional electrochemical performance. A hybrid supercapacitor assembled using the synthesized NiCo 2 S 4 @GO as a positive electrode and porous carbon as a negative electrode demonstrates a high energy density of 26.9 W h kg −1 at a power density of 658 W kg −1 in the voltage range 0–3.5 V. After 10,000 charge/discharge cycles, the device still retains 78% of its initial capacitance.