TiO2 nanosheets anchoring on carbon nanotubes for fast sodium storage

The ultrathin TiO2 nanosheets doped by nitrogen tightly attaching on carbon nanotubes are designed and evaluated as anode for sodium ion batteries. The TiO2 nanosheets attaching on carbon nanotubes composite shows a high specific capacity of 248.5 mAh g−1 at the rate of 0.5 C, and it can still deliver a specific capacity of 100.9 mAh g−1 at a high rate of 20 C, which verifies an outstanding sodium storage capacity and an excellent rate capability. More encouragingly, at a rate of 10 C, the specific capacity can be still kept at 154.2 mAh g−1 after 3500 cycles, displaying a remarkable long-term cyclic stability. Note that the corresponding kinetics analysis suggests that the pseudocapacitive behaviour is responsible for the updating sodium storage performances of TiO2 nanosheets composite. Additionally, the cooperation effects of carbon nanotubes preservation and nitrogen modification can provide fast electronic pathways, and the TiO2 nanosheets can promote sodium ions transport and increase the active sites for sodium storage. The merits of multiple functional and tailor-designed strategies make contributions to develop high-performance TiO2 anodes in sodium ion batteries.