Paper Title:

Li Conductivity of Nanocrystalline Li4Ti5O12 Prepared by a Sol-Gel Method and High-Energy Ball Milling

Periodical Defect and Diffusion Forum (Volumes 289 - 292)
Main Theme Diffusion in Materials - DIMAT2008
Edited by A. Agüero, J.M. Albella, M.P. Hierro, J. Phillibert and F.J. Pérez Trujillo
Pages 565-570
DOI 10.4028/www.scientific.net/DDF.289-292.565
Citation W. Iwaniak et al., 2009, Defect and Diffusion Forum, 289-292, 565
Online since April 2009
Authors W. Iwaniak, J. Fritzsche, M. Zukalová, R. Winter, Martin Wilkening, Paul Heitjans
Keywords Battery Materials, Impedance Spectroscopy, Lithium Titanate, Structural Disorder
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Spinel-type structured Li4+xTi5O12 (0 6 x 6 3 ) is actually one of the most promising anode materials for Li ion batteries. In its nanostructured form it is already used in some commercially available Li ion batteries. As was recently shown by our group (Wilkening et al., Phys. Chem. Chem. Phys. 9 (2007) 1239), Li diffusivity in microcrystalline Li4+xTi5O12 with x = 0 is rather slow. In the present contribution the Li conductivity in nanocrystalline samples of the electronic insulator Li4Ti5O12 prepared by different routes is investigated using impedance spectroscopy. The mean crystallite size of the samples is about 20 nm. The ionic conductivity of nanocrystalline Li4Ti5O12 obtained by mechanical treatment is higher by about two orders of magnitude compared to that found for a material which was prepared following a sol-gel method. The latter resembles the behaviour of the microcrystalline sample with an average particle size in the μm range rather than that of a nanocrystalline ball milled one with a mean crystallite size of about than 20 nm. The larger conductivity of the ball milled sample is ascribed to a much higher defect density generated when the particle size is reduced mechanically.