Mechano-thermally Activated Solid-state Synthesis of Li4Ti_5O_(12) Spinel from Li_2CO_3-TiO_2 Mixtures

摘要

Simultaneous TG/DSC measurements performed on mixtures 2Li_2CO_3-5TiO_2 (anatase) subjected to high-energy milling showed that both the temperature and the enthalpy of Li_2CO_3decomposition are much lower than in the case of TG/DSC runs performed on a sample of a physical mixture. On the basis of the thermoanalytical evidence a solid-state synthesis of the spinel compound Li_4Ti_5O_(12) has been proposed that combines mechanical (by high-energy milling) and thermal activation (8 h annealing at 973 K): the obtained compound shows a lattice constant in very good agreement with that expected for the pure phase Li_(1+x)Ti_(2-x)O_4 (x = 0.333). The molar heat capacity of Li_4Ti_5O_(12) has been determined in the temperature range 323-633 K by quasi-isothermal Modulated Differential Scanning Calorimetry (MDSC). The specific surface area of Li4Ti_5O_(12) has been determined by gas adsorption.