Facile synthesis of graphene supported ultralong TiO2 nanofibers from the commercial titania for high performance lithium-ion batteries

Abstract

Novel nanocomposites consisting of two-dimensional graphene nanosheets and ultralong TiO₂ nanofibers are fabricated via a simple one-pot hydrothermal reaction using commercial TiO₂ particles as inorganic precursors. Complex chemical synthesis processes and high cost precursors can be avoided. When used as anodes of lithium ion batteries, the obtained nanocomposites exhibit a superior rate capability and an excellent long-term cycling stability. The nanocomposites maintain a charge capacity of 85 mA h g⁻¹ at 20 C, while the TiO₂ nanofibers fail when cycled at 5 C. The nanocomposites also demonstrate an excellent cycling stability with a charge capacity of 92 mA h g⁻¹ after 1000 cycles at 10 C, approximately three times the capacity of the TiO₂ nanofibers. The superior electrochemical performance can be attributed to the hybrid structure of the graphene nanosheets and the ultralong TiO₂ nanofibers. The graphene nanosheets provide highly electronically conductive pathways and work as protected layers to keep the active material integrated during charging/discharging processes. The ultralong TiO₂ nanofibers with high specific surface area have a short ion diffusion distance and provide more accessible sites. By combining the advantages of the graphene nanosheets and TiO₂ nanofibers, the nanocomposites exhibit obviously improved electrochemical performances.