TiO₂(B) has attracted much interest as a fast and safe anode for lithium ion batteries as well as lithium ion capacitors owing to its high theoretical capacity (335 mAh g^-1), fast Li intercalation/de-intercalation properties and favorable electrode potential. TiO₂(B) can be synthesized by thermal treatment of layered titanate. We have shown that TiO₂(B) thin films can be prepared by utilizing electrophoretic deposition (EPD) of TiO₂ nanosheets [1]. Such methods afford TiO₂(B) film with the (0k0) planes lying perpendicular to the substrate.

In this study, the influence of the orientational structure (horizontal, vertical, random alignment) on the kinetics of Li⁺ storage in TiO₂(B) was studied by fabricating TiO₂(B) electrodes with the same mass loading by different orientation.

Vertically aligned TiO₂(B) films were prepared by a combination of EPD and freeze-drying. Randmoly stacked TiO₂(B) films was prepared by flocculation of nanosheets. Furthermore, the effect of the TiO₂(B) size was studied by using TiO₂ nanosheets with different lateral size. Electrochemical lithiation/de-lithiation studied in 1 M LiPF₆/EC-DEC by cyclic voltammetry and galvanostatic charge/discharge revealed that the orientation of TiO₂(B) had a large influence on Li⁺ storage kinetics. Perpendicularly aligned TiO₂(B) showed much faster Li⁺ intercalation/de-intercalation behavior compared to vertically aligned TiO₂(B) with the same mass loading. Randomly stacked TiO₂(B) possesed similar performance to vertically aligned TiO₂(B). High power capability was further improved by using smaller-sized TiO₂(B).

[1] W. Sugimoto, O. Terabayashi, Y. Murakami, Y. Takasu, J. Mater. Chem., 12, 3814-3818 (2002).