Anatase titania nanorods as an intercalation anode material for rechargeable sodium batteries

Nano Lett. 2014 Feb 12;14(2):416-22. doi: 10.1021/nl402747x. Epub 2014 Jan 16.

Abstract

For the first time, we report the electrochemical activity of anatase TiO2 nanorods in a Na cell. The anatase TiO2 nanorods were synthesized by a hydrothermal method, and their surfaces were coated by carbon to improve the electric conductivity through carbonization of pitch at 700 °C for 2 h in Ar flow. The resulting structure does not change before and after the carbon coating, as confirmed by X-ray diffraction (XRD). Transmission electron microscopic images confirm the presence of a carbon coating on the anatase TiO2 nanorods. In cell tests, anodes of bare and carbon-coated anatase TiO2 nanorods exhibit stable cycling performance and attain a capacity of about 172 and 193 mAh g(-1) on the first charge, respectively, in the voltage range of 3-0 V. With the help of the conductive carbon layers, the carbon-coated anatase TiO2 delivers more capacity at high rates, 104 mAh g(-1) at the 10 C-rate (3.3 A g(-1)), 82 mAh g(-1) at the 30 C-rate (10 A g(-1)), and 53 mAh g(-1) at the 100 C-rate (33 A g(-1)). By contrast, the anode of bare anatase TiO2 nanorods delivers only about 38 mAh g(-1) at the 10 C-rate (3.3 A g(-1)). The excellent cyclability and high-rate capability are the result of a Na(+) insertion and extraction reaction into the host structure coupled with Ti(4+/3+) redox reaction, as revealed by X-ray absorption spectroscopy.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.