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

Abstract

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.