Nanosized Effect on Electronic/Local Structures and Specific Lithium-Ion Insertion Property in TiO2-B Nanowires Analyzed by X-ray Absorption Spectroscopy

TiO2-B nanowires were prepared by hydrothermal reaction, and the nanosized effect on lithium-ion insertion was investigated by using X-ray absorption spectroscopy (XAS). On the basis of the results of 0 K-edge X-ray absorption near-edge structure (XANES) of TiO2-B with various particle sizes, it was suggested that the surface of TiO2-B has local and electronic structures being different from the bulk, and the band energy of surface of TiO2-B was lower than that of the bulk. The band vended structure, which is called the space charge layer (SCL), makes lithium-ion insertion in TiO2-B smooth because the local structure of the SCL is maintained during the lithium-ion insertion, which is shown by Ti K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. It is suggested that control of the SCL, that is the nanosized effect, is a new design concept for achieving higher rate capability.