Crystalline NiCo2S4 nanotube array coated with amorphous NiCo S for supercapacitor electrodes

Hierarchical NiCo2S4@NiCoxSy core/shell nanoarrays grown on carbon cloth were successfully synthesized via a two-step hydrothermal route and following an electrodeposition process. Compared with bare NiCo2S4, the electrochemical performance of NiCo2S4@NiCoxSy nanoarrays have been apparently improved, which shows areal capacitance as high as 3.9F/cm(2) at a constant current density of 1mA/cm(2). And the composite material exhibits excellent rate capability that a high areal capacitance of 2.9F/cm(2) is still retaining as the current density increase to 50mA/cm(2). The superior electrochemical performance can be attributed to the reasonably designed core/shell hierarchical structure of NiCo2S4@NiCoxSy nanoarrays, which would be promising for high-performance supercapacitor materials.