Electrochemical performance of Li4Ti5O12 anode material synthesised using polyethylene glycol as a template agent

Abstract

Low capacity and rate performance are important factors restricting the development of Li4Ti5O12 (LTO). The addition of an appropriate amount of polyethylene glycol (PEG) is an effective method to increase the capacity and rate performance of LTO anode material. In this study, LTO anode material was synthesised by the sol–gel method using PEG as a template agent. X-ray diffraction (XRD) results show that the addition of PEG can improve the crystallinity of the material and retain the spinel lattice type of LTO. Scanning electron microscopy (SEM) results show that the addition of an appropriate amount of PEG can promote the formation of a more uniform and much finer morphology. The results of high-resolution transmission electron microscopy (HRTEM) show that the material with PEG had good crystallinity. The charge and discharge data verify that the electrochemical performance of the material could be improved by adding PEG. P2-LTO exhibits a smaller particle size, largest capacity, best cycling performance and best rate performance. The capacity of P2-LTO at 0.2C can reach 224.3 mAgh−1, which is much higher than the theoretical specific capacity of LTO (175 mAgh−1). The discharge capacity of P2-LTO in the first cycle at 10C is 178.9 mAgh−1. The results of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) show that the electrode polarisation and electrochemical impedance of P2-LTO were lower than that of pure LTO. Better capacity and rate performance can be obtained by adding PEG as a template agent to a LTO system. It is a simple and effective method to produce high-performance LTO anode materials.