Carbon-decorated Li_4Ti_5O_(12)/rutile TiO_2 mesoporous microspheres with nanostructures as high-performance anode materials in lithium-ion batteries

摘要

Li4Ti_5O_(12)/rutile TiO_2 (LTO-RT) composites with Li/Ti molar ratios of 3:5, 4:5 and 4.5:5 have been successfully synthesized with TiO_2 microspheres as a precursor. Furthermore, C-coated LTO-RT mesoporous microspheres with a molar ratio of 4:5 (C/4-5-LTO-RT) have been prepared based on the LTO-RT composite through a hydrothermal method and high temperature calcination. After various characterizations, it is found that carbon plays a pivotal role in retaining the porous nanostructure of the original as-prepared TiO_2 precursor in the overall process. Substantially, C/4-5-LTO-RT still shows a high specific surface area of 63.70 m~2 g~(?1) even after high temperature treatment at 800 °C. Since the porous nanostructure offers open and direct channels for the diffusion of Li ions and electrons and carbon decoration also efficiently improves the electrical conductivity, the sample of C/4-5-LTO-RT shows an enhanced electrochemical performance. In addition, the presence of nanosized rutile TiO_2 in C/4-5-LTORT has an important contribution to the high electrochemical performance, as does the fast lithium ion diffusion along the [001] direction.