Engineering NiCo 2 S 4 nanoparticles anchored on carbon nanotubes as superior energy-storage materials for supercapacitors.

Fabricating high-capacity electrode materials toward supercapacitors has attracted increasing attention. Here we report a three-dimensional CNTs/NiCo 2 S 4 nanocomposite material synthesized successfully by a facile one-step hydrothermal technique. As expected, a CNTs/NiCo 2 S 4 electrode shows remarkable capacitive properties with a high specific capacitance of 890 C g -1 at 1 A g -1 . It also demonstrates excellent cycle stability with an 83.5% capacitance retention rate after 5000 cycles at 10 A g -1 . Importantly, when assembled into a asymmetric supercapacitor, it exhibits a high energy density (43.3 W h kg -1 ) and power density (800 W kg -1 ). The exceptional electrochemical capacity is attributed to the structural features, refined grains, and enhanced conductivity. The above results indicate that CNTs/NiCo 2 S 4 composite electrode materials have great potential application in energy-storage devices.