Sol–gel synthesis of aluminum doped lithium titanate anode material for lithium ion batteries

Abstract

In this study, spinel Li4Ti5−xAlxO12 (x=0, 0.05) materials were successfully synthesized by a simple and facile sol–gel process. The characteristics of the as-prepared Li4Ti5−xAlxO12 (x=0, 0.05) were examined by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and scanning electronic microscopy, while the electrochemical performances including charge/discharge test, cyclic voltammetry, and electrochemical impedance spectroscopy were also investigated. Li4Ti4.95Al0.05O12 electrode demonstrated the superior initial discharge capacity and rate capability to Li4Ti5O12 electrode cycled between 1.0 and 2.5V or between 0 and 2.5V. The enhanced rate capability can be attributed to the higher Li+ diffusivity and lower charge-transfer resistance due to the substitution of Al3+for Ti4+. Moreover, when both electrodes discharged to 0V, the reversible capacities were further increased ∼50mAhg−1 with excellent cycling stability and almost no irreversible capability was observed during cycling.