High-temperature effect on electrochemical performance of Li4Ti5O12 based anode material for Li-ion batteries

The electrochemical properties of Li4Ti5O12-rutile TiO2 (LTO-RTO) and Li4Ti5O12 (LTO) have been investigated at ambient temperatures from 25 degrees C to 60 degrees C. X-ray Diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) were utilized to characterize the structure, morphology and surface elemental composition of the electrodes after rate cycle at different temperature. The XRD and TEM results show that there is the strongest peak shift from (111) to (400) after rate cycle and the intensity ratio of these two peaks increased slightly at high temperature. The electrochemical results of the two anode materials indicate that the rate capabilities are sensitive to the high temperature for the lamellar structure clustered, the serious decomposition of electrolyte, the solid electrolyte interface resistance (R-SEI) substantially decreasing and the lithium ion diffusion rate enhancing with the ambient temperature increase. Nevertheless, LTO-RTO shows better rate capacity which is attribute to the existence of RTO which enables the LTO-RTO to maintain the lamellar staked structure at high temperature cycles and enhances the Li+ insertion/ extraction kinetics of the electrode. (C) 2018 Elsevier B.V. All rights reserved.