CNTs grown on oxygen-deficient anatase TiO2−δ as high-rate composite electrode material for lithium ion batteries

A CNTs–TiO2−δ composite consisting of carbon nanotubes (CNTs) grown by catalytic chemical vapor deposition on oxygen-deficient titanium dioxide (TiO2−δ) nanoparticles was synthesized and investigated as high-rate negative electrode material for Li-ion batteries. An initial reversible capacity of 185 mAhg− 1 was obtained at C/2, with an initial irreversible loss of 15%. The composite showed a high stability upon cycling, with 92% retention of the capacity after 37 cycles, and good high rate capability, with a capacity of 102 mAhg− 1 at 10C. The performance of the CNTs–TiO2−δ composite was compared to that of pristine commercial TiO2 and to that of oxygen-deficient TiO2 − δwith the aim of identifying the source of the improvement. Both TiO2−δ and CNTs network were found to contribute to the enhanced electrochemical performance of CNTs–TiO2−δ composite.

► TiO2 has two limitations: poor electron conductivity and sluggish ionic diffusivity.
► CNTs network is grown on the surface of commercial anatase TiO2 nanoparticle.
► Oxygen deficient titanium dioxide enhances conductivity within the particles.
► CNT network enhance conductivity through the film.
► Performance of the composite benefits from both the CNTs network and TiO2-δ.