Effects of TiO2 crystal structure on the performance of Li4Ti5O12 anode material

Li4Ti5O12 anode material is synthesized using TiO2 with different crystal structure as titanium source by solid-state method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical test methods are applied to characterize the effects of TiO2 crystal structure on the structure, morphology and electrochemical performance of Li4Ti5O12. Results show that the reaction of TiO2 with Li2CO3 is an exothermic behavior. The reactivity of TiO2 with Li2CO3 gradually decreases and the particles size of Li4Ti5O12 increases with the TiO2 crystal structure changing from amorphous to rutile. The TiO2 crystal structure has a slight influence on the reversibility of Li4Ti5O12, while the specific capacities of Li4Ti5O12 at different current densities decreases obviously with the TiO2 crystal structure changing from amorphous to rutile and the sample using amorphous TiO2 as titanium sources shows highest specific capacity. The capacity retentions of all Li4Ti5O12 samples are above 97% after 50 cycles and these materials show good cycle performance. The TiO2 crystal structure has not large effects on the cycling performance of Li4Ti5O12 material.

► The reactivity of TiO2 with Li2CO3 gradually decreases as the TiO2 crystal structure changes.
► The specific capacity of Li4Ti5O12 decreases obviously with the TiO2 crystal structure changing.
► The TiO2 crystal structure has not large effects on the cycling performance of Li4Ti5O12 material.
► The reaction of TiO2 with Li2CO3 is an exothermic behavior.