Design and synthesis of three-dimensional needle-like CoNi2S4/CNT/graphene nanocomposite with improved electrochemical properties

In this paper, we described a simple two-step method for preparing needle-like CoNi2S4/CNT/graphene nanocomposite with robust connection among its ternary components. The prepared CoNi2S4/CNT/graphene nanocomposite has been thoroughly characterized by spectroscopic (Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy), X-ray diffraction and thermogravimetric analysis. Microscopy techniques (scanning electron microscopy-energy dispersive spectroscopy and transmission electron microscopy) were employed to probe the morphological structures. The electrochemical properties of the as-prepared 3D architectures were investigated with three and two-electrode systems. In addition to its high specific capacitance (710 F g−1 at 20 A g−1), after charging-discharging for 2000 cycles, the electrode still maintained the capacity retention of about 82%. When used as the active electrode material for supercapacitors, the fabricated CoNi2S4-g-CNT nanostructure exhibited excellent specific capacitance and good rate capability, making it a promising candidate for next-generation supercapacitors.