Electrochemical performance of TiNb2O7/graphene/CNTs hybrid nanocomposites as anode materials for Li-ion batteries

In this study, the titanium niobium oxide (TiNb2O7)/ electrochemically exfoliated graphene/ carbon nanotubes (CNTs) hybrid nanocomposites with different hybrid ratios are synthesized by the solvothermal method for application as anode materials for lithium-ion batteries. Results indicated that the graphene sheets act as a substrate for the distribution of both TiNb2O7 nanoparticles and CNTs. Morphological studies showed the effective distribution of CNTs and TiNb2O7 nanoparticles on the surfaces and between the few-layered graphene in hybrid nanocomposites. Electrochemical studies showed the synergic effects of graphene and CNTs in improving the high-rate capacity and cyclic stability of the TiNb2O7. This study revealed that the electrochemical performance of hybrid nanocomposites is influenced by the mass ratio of graphene to CNTs. As the optimal sample, the samples with 1 wt% graphene and 2 wt% CNTs presented enhanced-cyclic stability (161 mAh/g after 200 cycles at a current density of 387 mA/g) and rate performance (74.4 mAh/g at a high current density of 7740 mA/g).