Carbon coated sodium-titanate nanotube as an advanced intercalation anode material for sodium-ion batteries

Na2Ti3O7 is a promising intercalation anode material for sodium ion batteries. However, low electronic conductivity and structural instability restrict its practical applications. Herein, a novel carbon coated sodium-titanate nanotube was successfully synthesized via a facile solvothermal method. The carbon combines all individual Na2Ti3O7 nanotubes into a stable union, which is characterized and confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The carbon encapsulation together with the unique nanotube structure of the Na2Ti3O7 endows the favorable high conductivity and improves the structural stability during cycling. Therefore, Na2Ti3O7@C electrode shows a much higher specific capacity and good cycling stability (142.2 mAh g(-1) at 311 mA g(-1) after 100 cycles), whereas the bare Na2Ti3O7 only shows a capacity of 84.9 mAh g(-1) at 311 mA g(-1) after 100 cycles. Furthermore, Na2Ti3O7@C composite electrode has relatively stable capacities at high rate current (84 mAh g(-1) at 3.11 A g(-1)). The present study provides a facile and scalable method to escalate the electrochemical performance of the intercalation anode materials for sodium ion batteries. (C) 2017 Elsevier B.V. All rights reserved.