A novel TiO2 nanoparticle-decorated helical carbon nanofiber composite as an anode material for sodium-ion batteries

Abstract In this study, a facile one-pot solvothermal method was employed to synthesize a helical carbon nanofibers@titanium dioxide (TiO2@HCNFs) composite, in which an anatase TiO2 coating layer with an average thickness of 20 nm was grafted in situ onto the surface of HCNFs. As a novel anode material for sodium-ion batteries (SIBs), TiO2@HCNFs retains a specific capacity of 193 mA h g-1 over 100 cycles at a current density of 0.1 A g-1, showing a significant enhancement; namely, a 187%, 148%, and 134% higher specific capacity than that obtained for pure HCNFs (103 mA h g-1), pure TiO2 (130 mA h g-1) and a TiO2-HCNFs mixture (143.5 mA h g−1), respectively. In addition, a capacity of 120 mA h g-1 can be maintained for TiO2@HCNFs even at a high current density of 2 A g-1. This excellent performance can be ascribed to the dual-phase combination of HCNFs/TiO2 and the sophisticated carbon coil structure, which improves the conductivity of TiO2 and shortens the distance for sodium-ion diffusion. Therefore, this work will bring about new possibilities for developing new anode materials for SIBs.