Structure and physical properties of Li4Ti5O12 synthesized at deoxidization atmosphere

Abstract

Powders of spinel Li4Ti5O12 (LTO) were successfully synthesized at reducing conditions by solid-state method. The structure and physical properties of Li4Ti5O12 were examined by X-ray diffraction (XRD), Raman spectroscopy, scanning electronic microscopy (SEM), and differential capacitance, respectively. XRD shows that both samples are single-phase spinel compounds. LTO synthesized in Ar/H2(8% mol) has a larger lattice parameter than that in Ar. SEM indicates that all of the prepared powders have the uniform, nearly cubic structure morphology with narrow size distribution in the range of 200–300 nm. Raman spectra indicate that the Raman bands corresponding to the Ti–O vibration has a blue shift from 674 to 680 cm−1 due to the few H2 in the synthesized condition, indicating that there is very few oxygen vacancies in the Li4Ti5O12 synthesized under Ar/H2 (8% mol). The dQ/dV vs. voltage plots reveals the redox potentials for the synthesized Li4Ti5O12-negative electrode materials.