Investigating thermal and kinetic parameters of lithium titanate formation by solid-state method

The lithium titanate formation through solid-state reaction between lithium carbonate and titanium dioxide was investigated with the help of thermogravimetry technique, under an inert atmosphere from ambient temperature to 1273 K at five (2, 5, 10, 15 and 20 K min(-1)) heating rates. The kinetic mechanism involved in the reaction was proposed by employing Criado method and Zhang method. The results revealed that the three-dimensional diffusion mechanism is involved in the formation of lithium titanate. Also, the kinetic parameters were determined by using Fynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunsose (KAS) isoconversional kinetic methods. The value of activation energy and pre-exponential calculated from FWO is 214.52 kJ mol(-1) and 4.96 x 10(-10) min(-1), whereas corresponding values calculated from KAS method are 211.27 kJ mol(-1) and 6.23 x 10(-9) min(-1), respectively. Furthermore, thermodynamic parameters such as enthalpy, entropy and Gibb's free energy were determined at all heating rates, in order to evaluate spontaneity of the reaction.