Isothermal kinetic analysis of the effects of high-energy ball milling on solid-state reaction of Li4Ti5O12

Abstract The effects of high-energy ball milling on the solid-state reaction were determined by X-ray diffractometry, scanning electron microscopy, and activation energy calculation, respectively. Isothermal kinetic analysis of solid-state reaction of Li 4 Ti 5 O 12 was studied using an isothermal thermogravimetric tests. The results indicate that the anatase to rutile transformation of TiO 2 and formation of Li 4 Ti 5 O 12 occur at a lower temperature, because the particle size of raw materials reduced by high-energy ball milling. In contrast to Jader equation, the model based on Johnson–Mehl–Avrami equation shows better linear fitting within temperature interval from 450 to 550 °C. The value of the kinetic parameter m is approximate to 0.4, indicating that the formation of products could be a diffusion controlled mechanism. Meanwhile, the activation energy of solid-state reaction decreases from 119.4 to 95.2 kJ/mol after high-energy ball milling. Electrochemical tests show that Li 4 Ti 5 O 12 samples synthesized by high-energy ball milling exhibit better rate capacity and cycle performance.