Ni2CoS4 nanocubes anchored on nitrogen-doped ultra-thin hollow carbon spheres to achieve high-performance supercapacitor

Metal sulfides, such as NiCo-sulfides, have attracted tremendous attention from the view of high conductivities and electrochemical activities. However, their structure degradation during the redox process causes cycling instability, which results in the limitation of the application of metal sulfides. Herein, we study the combination of metal sulfides with carbonaceous materials. The NHCS/Ni2CoS4 composite is synthesized via a facile two-step method that entails first the fabrication of the N-doped hollow carbon spheres (NHCS) followed by the loading of Ni2CoS4 nanocubes into the NHCS via hydrothermal synthesis. The as-obtained NHCS/Ni2CoS4 composite electrode shows a super electrochemical performance (1465 F g−1 at 0.5 A g−1) and has a satisfactory cycling stability (87.4% capacitance retention). These results indicate that NHCS/Ni2CoS4 is a promising electrode material for high-performance supercapacitors.