Carbon-coated anatase titania as a high rate anode for lithium batteries

Abstract Anatase titania nanorods/nanowires, and TiO 2 (B) are synthesized via a hydrothermal reaction of commercial TiO 2 (P-25) in strong alkaline environment. Surfaces of these products are modified by carbon to improve the electrical conductivity through carbonization of pitch as the carbon source at 700 °C for 2 h in an Ar atmosphere. Even after carbon coating, the resultants exhibit the same crystal structure and morphology as confirmed by Rietveld refinement of x-ray diffraction data and transmission electron microscopic observation that the images display thin carbon coating layers on the surfaces of anatase nanorods and nanowires. Although the bare and carbon-coated anatase TiO 2 nanorods exhibit stable cycling performance, the high rate performance is highly dependent on the presence of carbon because of high electrical conductivity, ∼10 −1  S cm −1 , enabling Li + ion storage even at 30 °C (9.9 A g −1 ) approximately 100 mAh (g-TiO 2 ) −1 for the carbon-coated anatase TiO 2 nanorods. Besides, the bare and carbon-coated anatase TiO 2 nanowires show poor electrode performances due to their large particle size and high crystallinity causing Li + insertion into the host structure difficult. It is believed that the conducting carbon coating layers greatly improves the electrochemical property through the improved electrical conductivity and shortened diffusion path.