One-step hydrothermal synthesis of NiCo2S4 nanoplates/nitrogen-doped mesoporous carbon composites as advanced electrodes for asymmetric supercapacitors

NiCo2S4 nanoplates grow on nitrogen-doped mesoporous carbon (N-MC) are successfully synthesized through a facile one-step hydrothermal method. Study on the synergistic effect of NiCo2S4 and N-MC substrate on the electrochemical properties of composites. The NiCo2S4/N-MC composites electrode exhibits large specific capacitance of 1777 F g(-1) at 8 A g(-1), excellent rate capability, and an ultralong cycle life (94.20% retention after 3000 cycles at 10 A g(-1)), which is higher than the pure NiCo2S4. The N-MC substrate has a large specific surface area (126.7 m(2) g(-1)), which can serve as a channel for electrolyte ions and electrons, promote reaction kinetics, and shorten the diffusion distance in redox reaction, thereby improving the performance of pure NiCo2S4. Additionally, the as-synthesized asymmetric supercapacitors based on NiCo2S4/N-MC//N-MC electrodes can be delivered a maximum energy density of 78 W h kg(-1) at 4000 W kg(-1) and stable cycling stability (91.30% after 5000 cycles). The results demonstrate that the hierarchical NiCo2S4/N-MC composites have great potential applications in energy storage.