Superior rate performance of Li4Ti5O12/TiO2/C/CNTs composites via microemulsion-assisted method as anodes for lithium ion battery

Spinel Li4Ti5O12 (LTO) is a promising anode material of lithium ion batteries for electric vehicles and hybrid electric vehicles due to its long cycle life, well-known stable structure, and high safety. Whereas, the electronic conductivity of spinel LTO is intrinsically low. To circumvent this drawback, composites of Li4Ti5O12/TiO2/Carbon/Carbon nanotubes (LTO/TiO2/C/CNTs) are prepared by a novel wet-chemical method (reversed-phase microemulsion method), including high electronic conductive CNTs and excess TiO2. The presence of carbon can suppress the growth of LTO particles and lead the appearance of TiO2 during synthesis process. The average particle size of LTO is about 30 nm. The LTO/TiO2/C/CNTs composites deliver exceptional electrochemical performance in the voltage window 1.0 -2.5V. It presents a discharge capacity of 224 mAh.g(-1) at 0.15 C and 95 mAh.g(-1) at a high current rate of 24C (4.2 A.g(-1)). It is found that the TiO2 not only has electrochemical activity but also results in interfacial effect to hugely increase its rate performance. (C) 2014 Elsevier Ltd. All rights reserved.