Great efforts have been devoted for the synthesis of Li4Ti5O12 nanoparticles as anode material, because particle size less than 100 nm is the main factor for achieving a high rate capability. In this study, we fabricated nano-sized Li4Ti5O12 by high-energy milling operated at 3500 rpm, that it was treated afterwards by post-calcination to improve its pulverized crystallinity. Post-calcination at moderate temperature is found to be effective for improving the electrochemical properties of Li4Ti5O12 prepared by mechanical pulverization. Finally, a 100 nm-sized Li4Ti5O12 was successfully obtained by optimizing the high-energy milling passing 10 times in chamber and setting post-calcination to 700 degrees C. The specific capacity significantly depended on the crystallinity of Li4Ti5O12 after treated by the post -calcination. The 100 nm-sized Li4Ti5O12 showed high-rate capability and good capacity retention of 99.9% after 1500 cycles. It can be explained by the synergistic effect of reduced particle size and improved crystallinity. (C) 2016 Published by Elsevier B.V.