High rate capability of TiO2/nitrogen-doped graphene nanocomposite as an anode material for lithium–ion batteries

Abstract

TiO2/nitrogen-doped graphene nanocomposite was synthesized by a facile gas/liquid interface reaction. The structure and morphology of the sample were analyzed by X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The results indicate that nitrogen atoms were successfully doped into graphene sheets. The TiO2 nanoparticles (8–13nm in size) were homogenously anchored on the nitrogen-doped graphene sheets through gas/liquid interface reaction. The as-prepared TiO2/nitrogen-doped graphene nanocomposite shows a better electrochemical performance than the TiO2/graphene nanocomposite and the bare TiO2 nanoparticles. TiO2/nitrogen-doped graphene nanocomposite exhibits excellent cycling stability and shows high capacity of 136mAhg−1 (at a current density of 1000mAg−1) after 80cycles. More importantly, a high reversible capacity of 109mAhg−1 can still be obtained even at a super high current density of 5000mAg−1. The superior electrochemical performance is attributed to the good electronic conductivity introduced by the nitrogen-doped graphene sheets and the positive synergistic effect between nitrogen-doped graphene sheets and TiO2 nanoparticles.