Alignment and Size Control of TiO2(B) for Fast Lithium Storage

Monday, 2 October 2017: 14:40
Chesapeake 6 (Gaylord National Resort and Convention Center)
W. Sugimoto, T. Yoshida, R. Tanaka, S. Makino, Y. Ayato, and D. Mochizuki (Shinshu University)
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).