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.