Synthesis and enhanced supercapacitor performance of carbon self-doping graphitic carbon nitride/NiS electrode material

The thermal oxidation carbon self-doped graphitic carbon nitride/NiS (TC-g-C₃N₄/NiS) composites with high electrochemical performance were synthesized by combining nickel sulfide with carbon self-doping carbon nitride through a hydrothermal method. The graphitic carbon nitride (g-C₃N₄) could improve charge fluidity by carbon self-doping process, and be etched by further heat treatment, which provides conditions for the introduction of NiS particles. NiS particles uniformly adhered to the layers of g-C₃N₄, thus avoiding particle aggregation. The as-prepared active composite maintains high specific capacitance (1162 F/g at the current density of 1 A·g⁻¹) and shows great cycle stability (capacitance retention rate of 82.0% after 8000 cycles). The conductivity of active composite has also been improved. Moreover, the assembled TC-g-C₃N₄/NiS//AC exhibit a relatively high-energy density of 27 Wh/kg and exhibits excellent cycling performance with a capacity retention rate of 87.9% after 8000 cycles. Hence one can see that TC-g-C₃N₄/NiS composites have broad application prospects in the field of supercapacitors.