One-step synthesis of layered CuS/multi-walled carbon nanotube nanocomposites for supercapacitor electrode material with ultrahigh specific capacitance

In this work, hierarchical-structured copper sulfide/multi-walled carbon nanotubes (CuS/MWCNTs) are synthesized via a one-step hydrothermal process. The chemical composition and microstructure of CuS-MWCNTs are characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy and research as electrode matericals for high-performance supercapacitors by cyclic voltammogram, galvanostatic charge-discharge and electrochemical impedance spectroscopy. As expected, the CuS-MWCNTs exhibit a much higher specific capacitance up to 2831 F g−1, compared with 925.1 F g−1 for CuS and 555.6 F g−1 for MWCNTs. Furthermore, the CuS-MWCNTs hybrids also exhibit good cycling stability with more than 90% capacitance retention over 600 cycles. The enhancement of CuS/MWCNTs in supercapacitor performance not only attribute to their unique 3D structures with large specific surface area, but also their excellent conductivity, which facilitate efficient charge transport and promotes electrolyte diffusion.