Table of Contents
ISRN Nanotechnology
Volume 2011, Article ID 180821, 6 pages
http://dx.doi.org/10.5402/2011/180821
Research Article

Transition Metal-Doped Lithium Titanium Oxide Nanoparticles Made Using Flame Spray Pyrolysis

1Fine Particle and Aerosol Technology Laboratory, Department of Environmental Science, University of Eastern Finland, 70211 Kuopio, Finland
2Particle Technology Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich, Switzerland
3Fine Particles, VTT Technical Research Centre of Finland, 02044 VTT, Finland

Received 2 August 2011; Accepted 18 September 2011

Academic Editors: B.-R. Huang and L. Y. Khomenkova

Copyright © 2011 T. Karhunen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Defect spinel phase lithium titanate (Li4Ti5O12) has been suggested as a promising negative electrode material for next generation lithium ion batteries. However, it suffers from low electrical conductivity. To overcome this problem conduction path length can be reduced by decreasing the primary particle size. Alternatively the bulk conductivity of Li4Ti5O12 can be increased by doping it with a conductive additive. In this paper a steady, single-step gas-phase technique for lithium titanate synthesis that combines both approaches is described. The process is used to produce doped Li4Ti5O12 nanoparticles with primary particle size of only 10 nm. The product is found to consist of single-crystalline nanoparticles with high phase and elemental purity. Two dopant materials are tested and found to behave very differently. The silver dopant forms a separate phase of nanometre-sized particles of metallic silver which agglomerate with Li4Ti5O12. The copper dopant, on the other hand, reacts with the lithium titanate to form a double spinel phase of Li3(Li12𝑥Cu3𝑥Ti5𝑥)O12.