A Novel TiO <sub>2</sub> 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 nanofiber@titanium dioxide (TiO2@HCNF) 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@HCNF 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-HCNF mixture (143.5 mA h g−1), respectively. In addition, a capacity of 120 mA h g-1 can be maintained for TiO2@HCNF 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.