Block-shaped pure and doped Li4Ti5O12 containing a high content of a Li2TiO3 dual phase: an anode with excellent cycle life for high rate performance lithium-ion batteries

摘要

Pure and doped lithium titanate samples (Li4Ti5O12, Li(4)Ti(4.9)x(0.1)O(12), x = Ni2+, Cu2+ and Zn2+) are prepared using a simple solid state reaction. All lithium titanate samples are characterized using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. X-ray diffraction patterns show a cubic spinel structure of Li4Ti5O12 with different contents of a Li2TiO3 crystalline second phase, high for the doped samples and low for the pure one. Fourier transform infrared spectra also confirm the spinel structure. Scanning electron microscopy shows block-shaped particles with different particle size distributions. The pure lithium titanate composite sample shows more efficient electrochemical performance than the doped ones at high discharge rates (2-30C) and the opposite is observed at low ones (0.1, 0.5C). The efficiency and cycle life of the pure lithium titanate composite at a high rate (30C) are higher and better than that at a low one (0.1C), making the pure composite a promising anode material for high rate lithium-ion batteries. All results are collected and discussed.