Characteristics of spherical-shaped Li4Ti5O12 anode powders prepared by spray pyrolysis

Spherical-shaped Li4Ti5O12 anode powders with a mean size of 1.5 mu m were prepared by spray pyrolysis. The precursor powders obtained by spray pyrolysis had no peaks of crystal structure of Li4Ti5O12. The powders post-treated at temperatures of 800 and 900 degrees C had the single phase of spinel Li4Ti5O12. The powders post-treated at a temperature of 1000 degrees C had main peaks of the Li4Ti5O12 phase and small impurity peaks of Li2Ti3O7. The spherical shape of the precursor powders was maintained after posttreatment at temperatures below 800 degrees C. The Brunauer-Emmett-Teller (BET) surface areas of the Li4Ti5O12 anode powders post-treated at temperatures of 700, 800 and 900 degrees C were 4.9, 1.6 and 1.5 m(2)/g, respectively. The initial discharge capacities of Li4Ti5O12 powders were changed from 108 to 175 mAh/g when the post-treatment temperatures were changed from 700 to 1000 degrees C. The maximum initial discharge capacity of the Li4Ti5O12 powders was obtained at a post-treatment temperature of 800 degrees C, which had good cycle properties below current densities of 0.7 C. (C) 2008 Elsevier Ltd. All rights reserved.