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

A facile solid-state method to improve the rate performance of Li 4 Ti 5 O 12 in lithium-ion batteries by LiAlO 2 in situ modification is presented in this work. XRD shows that the LiAlO 2 modification does not change the spinel structure of Li 4 Ti 5 O 12 but forms Al-doped Li 4 Ti 5 O 12 –LiAlO 2 composites, and little Al doping decreases the lattice parameter of doped Li 4 Ti 5 O 12 . SEM shows that all samples are composed of 1–2 μm primary particles with irregular shapes. Raman spectra reveal that the intensity of these lines for Li 4 Ti 5 O 12 –LiAlO 2 composites obviously decreases caused by a modification of the LiAlO 2 phase. CV and EIS tests indicate that the doping of Al 3+ and the combination with in situ generated LiAlO 2 on the surface of Li 4 Ti 5 O 12 are favorable for reducing the electrode polarization and charge-transfer resistance, and then improve the reversibility and lithium ion diffusion coefficient of Li 4 Ti 5 O 12, resulting in its relatively higher rate capacity. Charge–discharge tests reveals that Li 4 Ti 5 O 12 –LiAlO 2 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.