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

Spherical-shaped Li4Ti5O12 anode powders with a mean size of 1.5 μm 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 °C had the single phase of spinel Li4Ti5O12. The powders post-treated at a temperature of 1000 °C had main peaks of the Li4Ti5O12 phase and small impurity peaks of Li2Ti3O7. The spherical shape of the precursor powders was maintained after post-treatment at temperatures below 800 °C. The Brunauer–Emmett–Teller (BET) surface areas of the Li4Ti5O12 anode powders post-treated at temperatures of 700, 800 and 900 °C were 4.9, 1.6 and 1.5 m2/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 °C. The maximum initial discharge capacity of the Li4Ti5O12 powders was obtained at a post-treatment temperature of 800 °C, which had good cycle properties below current densities of 0.7 C.