High-rate characteristics of novel anode Li4Ti5O12/polyacene materials for Li-ion secondary batteries

In recent years, spinel lithium titanate (Li4Ti5O12) as a superior anode material for energy storage battery has attracted a great deal of attention because of the excellent Li-ion insertion and extraction reversibility. However, the high-rate characteristics of this material should be improved if it is used as an active material in large batteries. One effective way to achieve this is to prepare electrode materials coated with carbon. A Li4Ti5O12/polyacene (PAS) composite were first prepared via an in situ carbonization of phenol-formaldehyde (PF) resin route to form carbon-based composite. The SEM showed that the Li4Ti5O12 particles in the composite were more rounded and smaller than the pristine one. The PAS was uniformly dispersed between the Li4Ti5O12 particles, which improved the electrical contact between the corresponding Li4Ti5O12 particles, and hence the electronic conductivity of composite material. The electronic conductivity of Li4Ti5O12/PAS composite is 10(-1) S cm(-1), which is much higher than 10(-9) S cm(-1) of the pristine Li4Ti5O12. High specific capacity, especially better high-rate performance was achieved with this Li4Ti5O12/PAS electrode material. The initial specific capacity of the sample is 144 mAh/g at 3 C, and it is still 126.2 mAh/g after 200 cycles. By increasing the current density, the sample still maintains excellent cycle performance. (c) 2007 Elsevier Ltd. All rights reserved.