Stable spinel material Li4Ti5O12 was prepared through solid-state reaction using H2TiO3, Li2CO3 and PEG2000 as precursors. The phase purity and microstructure of the synthesized powders were studied by X-ray diffraction, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The particles are well dispersed with diameters distributed in the range of 100-150 nm. Li4Ti5O12 was doped with different mole fractions of Mg to improve the electrochemical performance of the sample at a high current rate. The best charge and discharge capacities, 145 mAh/g and 149 mAh/g, were obtained as 3 at% Mg was doped when the current density was 0.1 C. The rate property of Li4Ti5O12 could also be enhanced by the doping of Mg. (C) 2010 Elsevier B.V. All rights reserved.