Anodically fabricated TiOSnO nanotubes and their application in lithium ion batteries

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2016-04, Vol.4 (15), p.5542-5552
• Main Authors: Madian, M, Klose, M, Jaumann, T, Gebert, A, Oswald, S, Ismail, N, Eychmller, A, Eckert, J, Giebeler, L
• Format: Article
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c6ta00182c

Developing novel electrode materials is a substantial issue to improve the performance of lithium ion batteries. In the present study, single phase TiSn alloys with different Sn contents of 1 to 10 at% were used to fabricate TiSnO nanotubes via a straight-forward anodic oxidation step in an ethylene glycol-based solution containing NH 4 F. Various characterization tools such as SEM, EDXS, TEM, XPS and Raman spectroscopy were used to characterize the grown nanotube films. Our results reveal the successful formation of mixed TiO 2 /SnO 2 nanotubes in the applied voltage range of 1040 V. The as-formed nanotubes are amorphous and their dimensions are precisely controlled by tuning the formation voltage which turns TiSnO nanotubes into highly attractive materials for various applications. As an example, the TiSnO nanotubes offer promising properties as anode materials in lithium ion batteries. The electrochemical performance of the grown nanotubes was evaluated against a Li/Li + electrode at a current density of 504 A cm 2 . The results demonstrate that TiO 2 /SnO 2 nanotubes prepared at 40 V on a TiSn 1 alloy substrate display an average 1.4 fold increase in areal capacity with excellent cycling stability over more than 400 cycles compared to the pure TiO 2 nanotubes fabricated and tested under identical conditions. This electrode was tested at current densities of 50, 100, 252, 504 and 1008 A cm 2 exhibiting average capacities of 780, 660, 490, and 405 A cm 2 ( i.e. 410, 345, 305 and 212 mA h g 1 ), respectively. The remarkably improved electrochemical performance is attributed to enhanced lithium ion diffusion which originates from the presence of SnO 2 nanotubes and the high surface area of the mixed oxide tubes. The TiO 2 /SnO 2 electrodes retain their original tubular structure after electrochemical cycling with only slight changes in their morphology. Developing novel electrode materials is a substantial issue to improve the performance of lithium ion batteries.