Synthesis of NiO/carbon shell/single-walled carbon nanotube composites as anode materials for lithium ion batteries

•NiO/carbon shell/single-walled carbon nanotube composites were prepared.•The morphology of the composites was affected by heat treating temperature.•The unique nanostructure of the composites was investigated.•Electrochemical measurements show good cyclic stability and rate performance.

In this study, NiO/carbon shell/single-walled carbon nanotube composites are prepared by heat treating the single-walled carbon nanotube samples synthesized by direct current arc discharge method. The morphology and nanostructure of the composites are affected by the heat treatment temperature according to the X-ray diffraction, Raman spectra and high-resolution transmission electron microscopy results. The electrochemical measurements are evaluated in coin-type cells versus metallic lithium. After heat treatment in H2 at 600 °C for 1 h and in air at 300 °C for 10 h, the NiO nanoparticles encapsulated by carbon shells are evenly distributed on the surface of web-like single-walled carbon nanotubes and a perfect NiO/carbon shell/single-walled carbon nanotube nanostructure is formed. This NiO/carbon shell/single-walled carbon nanotube composite shows a high reversible specific capacity of 758 mA h g−1 after 60 cycles at a current density of 100 mA g−1 and an excellent rate capacity of about 594 mA h g−1 even at a high current density of 1600 mA g−1. Therefore, the NiO/carbon shell/single-walled carbon nanotube composites have significant potential for applications in energy storage devices.

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