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

Abstract

• Gram-scale produced Helical Carbon NanoFibers were used as the matrix. • A novel TiO2@HCNFs compound was firstly fabricated for sodium batteries. • Unique helical nanostructure plays a vital role in electrochemical performance. In this study, a facile one-pot solvothermal method was employed to synthesize a helical carbon nanofibers@titanium dioxide (TiO 2 @HCNFs) composite, in which an anatase TiO 2 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), TiO 2 @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 TiO 2 (130 mA h g −1 ) and a TiO 2 -HCNFs mixture (143.5 mA h g −1 ), respectively. In addition, a capacity of 120 mA h g −1 can be maintained for TiO 2 @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/TiO 2 and the sophisticated carbon coil structure, which improves the conductivity of TiO 2 and shortens the distance for sodium-ion diffusion. Therefore, this work will bring about new possibilities for developing new anode materials for SIBs.