Effects of different carbon sources on the electrochemical properties of Li4Ti5O12/C composites

Li4Ti5O12/C composites have been synthesized via a solid state reaction with TiO2-anatase, Li2CO3 and different carbon sources, such as conductive graphite KS-6 and sucrose, as the starting materials. It was found that the carbon layer from sucrose was homogeneously coated on the Li4Ti5O12 surface and the KS-6 was embedded among the Li4Ti5O12 particles as a conductive bridge without affecting the spinel structure of Li4Ti5O12. Moreover, it was demonstrated that the sucrose and KS-6 played different roles in improving the electrochemical properties of Li4Ti5O12/C composite. Compared with samples prepared by solely KS-6 or sucrose as the carbon source, the Li4Ti5O12/C composite (LTO-1) with KS-6 and sucrose as carbon sources together revealed the optimal electrochemical performance. It showed a high initial specific capacity of 152.5 mAh g−1 at 0.2 C and an excellent cycling performance with 96.8% capacity retention after 1000 cycles at 25 °C at 1 C. Furthermore, the (LTO-1)/LiMn2O4 full battery demonstrated a good cycling performance at 55 °C and could pass the 5 C–20 V overcharge test, external short-circuit and nail-puncture test. Therefore, it is believed that the Li4Ti5O12/C might be a promising anode material for large-scale lithium ion batteries of electric vehicle (EV), hybrid electric vehicle (HEV) and energy storage devices for solar or wind energy.

► The Li4Ti5O12/C (LTO-1) with two kinds of carbon cooperatively was synthesized.
► Effects of different carbon on electrochemical property of composites were studied.
► LTO-1 has good electronic conductivity in particle itself and among the particles.
► The synthesis process is environment friendly, and easy to industrialization.