Novel 3D flower-like CoNi2S4/carbon nanotube composites as high-performance electrode materials for supercapacitors

Novel 3D flower-like CoNi2S4/carbon nanotube composites with a porous structure were designed through a facile precursor transformation approach as electrode materials for supercapacitors. The resulting samples are characterized by X-ray diffraction, Raman spectra, energy dispersive spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption-desorption. Their electrochemical performance was investigated by means of cyclic voltammetry, galvanostatic charge-discharge, impedance spectra and cycle life. By selecting carbon nanotubes as the conductive support for the growth of CoNi2S4, the as-obtained CoNi2S4/carbon nanotube composites displayed an ultrahigh specific capacitance of 2094 F g(-1) at 1 A g(-1) and a good rate capability (72% capacity retention at 10 A g(-1)). These results above suggest the great potential of the unique flower-like CoNi2S4/carbon nanotube composites in the development of high-performance electrode materials for supercapacitors.