Designing a hierarchical structure of nickel-cobalt-sulfide decorated on electrospun N-doped carbon nanofiber as an efficient electrode material for hybrid supercapacitors

The intent of designing and exploring novel active electrode materials is to enhance the electrochemical performance of supercapacitors. Herein, a hierarchical structure of nickel-cobalt-sulfide nanostructures (NiCo2S4) decorated on the electrospun N-doped carbon nanofiber (CNF), NiCo2S4@CNF, is manipulated using a one-step and simple hydrothermal approach. The fabricated hierarchical structure of the NiCo2S4@CNF is featured by a large surface area and a high porosity that serve as ion diffusion channels. Therefore, it manifests high specific capacitance and specific capacity values of 377.2 C g−1 and 754.4 F g−1 at a current density of 1 A g−1, respectively. Furthermore, a NiCo2S4@CNF//CNF hybrid supercapacitor in which a positive electrode of NiCo2S4@CNF is assembled with a negative electrode of CNF to estimate the electrochemical performance of the NiCo2S4@CNF. As a result, the device has a superior energy density of 65.6 and 52.5 Wh kg−1 at a power density of 665 and 1313.8 W kg−1, respectively. Moreover, the device reveals good stability with capacitance retention of 72% after 3000 charge/discharge cycles. These outstanding results enable the designed hierarchical structure of the NiCo2S4@CNF to be a promising electrode material for supercapacitors (SCs) applications.