Nano-micro structure VO2/CNTs composite as a potential anode material for lithium ion batteries

VO 2 is considered as a promising anode material for lithium ion batteries , owing to its high theoretical capacity and fast ion-transfer rate. However, the development of VO 2 is hindered by the severe issues of poor electrical conductivity , large volume changes and low energy density . In this study, nano-micro structure VO 2 /CNTs spheres are well designed and successfully synthesized through a one-step solvothermal method, where the carbon nanotubes are inlayed throughout the whole microspheres . This unique structure enables carbon nanotubes to improve the ion and electron conductivity of VO 2 . Besides, it can achieve a high tap density (> 1.3 g cm 3 ) of VO 2 /CNTs electrode, which is higher than nanomaterials (< 1.0 g cm 3 ), and compatible with the current commercial anode materials. The Li + storage behavior of VO 2 /CNTs is studied systematically in the potential range 0.01–3.0 V, it can obtain a high reversible specific capacity of 537.6 mA h g −1 at the current density of 0.05 A g −1 . Furthermore, the lithium insertion/extraction reaction mechanism of nano-micro structure VO 2 /CNTs is clarified. The results demonstrate that the nano-micro structure relieves the volume changes during charge/discharge cycling. Therefore, it provides an insight to create functional materials with nano-micro structure for a wide range application.