Li4Ti5O12-LiAlO2 Composite as High Performance Anode Material for Lithium-Ion Battery

A facile solid-state method to improve the rate performance of Li4Ti5O12 in lithium-ion batteries by LiAlO2 in situ modification is presented in this work. XRD shows that the LiAlO2 modification does not change the spinet structure of Li4Ti5O12 but forms Al-doped Li4Ti5O12-LiAlO2 composites, and little Al doping decreases the lattice parameter of doped Li4Ti5O12. SEM shows that all samples are composed of 1-2 mu m primary particles with irregular shapes. Raman spectra reveal that the intensity of these lines for Li4Ti5O12-LiAlO2 composites obviously decreases caused by a modification of the LiAlO2 phase. CV and EIS tests indicate that the doping of Al3+ and the combination with in situ generated LiAlO2 on the surface of Li4Ti5O12 are favorable for reducing the electrode polarization and charge-transfer resistance, and then improve the reversibility and lithium ion diffusion coefficient of Li4Ti5O12, resulting in its relatively higher rate capacity. Charge-discharge tests reveals that Li4Ti5O12-LiAlO2 composite (5 wt %) exhibits the highest rate capacity and cycling stability at various rates, which is capable of large-scale applications, such as electric vehicles and hybrid electric vehicles, requiring high energy, long life and excellent safety.