Atomistic computer modelling was applied to the structure of -Spodumene, and a general Li-O potential was developed for use with this and other similar silicates. Defect calculations were used to study Li+ ion migration through this structure. It was found that the above potential reproduced well the structure of this, and other Li alumino-silicates. The calculated Li vacancy migration energy (0.8eV) had the same value as the measured energy for Li ion conduction. It was noted that conductivity plots revealed only a single Arrhenius energy over the entire measured temperature range. This suggested that the samples were extremely pure and that the Arrhenius energy was the sum of a defect migration and formation energy, or that the samples contained extrinsic defects and the Arrhenius energy was simply a defect migration energy. The good agreement between experimental data and the present calculations implied that the latter interpretation was to be preferred; with the migrating defect being a Li ion vacancy. It was proposed that these extrinsic defects were due to aliovalent impurities or to non-stoichiometry.

A Computer Simulation Study of β-Spodumene. G.Morrison, C.M.Barker, K.M.Kennedy, A.V.Chadwick: Materials Science Forum, 1997, 239-241, 417-20