The solid electrolyte Li1+2xMgxTi2-xP3O12 compounds were synthesized by a solid state reaction. The ceramic samples were sintered for 0.2, 0.5, 1 and 3h and studied by X-ray and complex impedance spectroscopy at 10Hz to 1.2GHz and 300 to 600K. Two regions of relaxation dispersion were found, the dispersions were related to the fast Li+ ion transport in the bulk and grain boundaries. Varying of the sintering time affects the

density, values of grain boundary conductivity (σgb), its activation energy (ΔEgb) and relaxation frequency (fgb). The activation energy (ΔEb) of bulk conductivity (σb) and activation energy (ΔEf) of relaxation frequency (fb) in the bulk were the same. That could be attributed to the fact that the temperature dependence of the bulk conductivity was caused only by the mobility of the fast Li+ ions, while a number of charge carriers remained constant with temperature.

Synthesis, Structure and Peculiarities of Ionic Transport of Li1.6Mg0.3Ti1.7(PO4)3 Ceramics. A.Orliukas, A.Dindune, Z.Kanepe, J.Ronis, E.Kazakevicius, A.Kežionis: Solid State Ionics, 2003, 157[1-4], 177-81