Synthesis of pure nano-sized Li4Ti5O12 powder via solid-state reaction using very fine grinding media

Li4Ti5O12 was synthesized by a solid-state reaction using Li2CO3 and anatase TiO2 at 800 °C for 3 h for anode application in Li-ion batteries. In order to examine the effects of milling conditions on the properties of Li4Ti5O12, 3 different ZrO2 media of sizes 0.45, 0.10 and 0.05 mm were subjected to 5 h of high energy milling, while 5 mm balls were subjected to 24 h of ball milling for comparison. High energy milling was found to be much more effective in decreasing both the reaction temperature and the final Li4Ti5O12 particle size than ball milling through the efficient size reduction and mechanochemical activation of the starting materials. The use of 0.10 and 0.05 mm beads resulted in the synthesis of pure nanosized Li4Ti5O12, depressing the formation of unwanted rutile TiO2 in the final products, whereby the finer milling media showed more desirable particle properties. Consequently, pure Li4Ti5O12 of 145 nm size, which is comparable to the particle sizes from expensive wet chemical methods, could be synthesized by an economic solid-state reaction.