The Li-ion conducting glass and glass ceramic with the composition, Li1.4[Al0.4Ge1.6(PO4)3], was synthesized. Heat treatment of monolithic glass pieces resulted in single-phase glass ceramics with a Nasicon structure. Experiments on various electrodes proved that the Li electrodes provided accurate values for the ionic conductivity using impedance spectroscopy. The ionic conductivity of the glass ceramic was found to be 3.8 x 10-5S/cm at 40C, with an activation energy of 0.52eV. The corresponding values for the glass were: 2.7 x 10-9S/cm and 0.95eV, respectively. The Arrhenius dependence of the ionic conductivity in the glass and glass ceramic was interpreted in terms of a hopping mechanism, from which the microscopic characteristics of Li cation motion were deduced.

Lithium Conducting Glass Ceramic with Nasicon Structure. C.J.Leo, B.V.R.Chowdari, G.V.Subba Rao, J.L.Souquet: Materials Research Bulletin, 2002, 37[8], 1419-30