DISTRIBUTION OF ACTIVATION-ENERGIES EXPLAINS IONIC MOTION IN GLASSY FAST-ION CONDUCTORS - LI-7 NMR SPIN-LATTICE RELAXATION AND IONIC-CONDUCTIVITY IN XLI(2)S-X)GES2((1)

We report Li-7 nuclear spin-lattice relaxation (NSLR) measured at 4, 1 2.1 and 22 MHz, and conductivity measured from 1 Hz to 10 MHz from 100 to 500 K, on a series of xLi(2)S + (1-x)GeS2 glasses with x = 0.35, 0 .45 and 0.55. These data were used to examine the quality of the model for the ionic motion and the ionic conductivity in Li+ glassy fast io n conductors (FIC) obtained by describing the ionic hopping motion wit h a distribution of activation energies (DEA) derived from the Li-7 NS LR. We find that the distribution of activation energies obtained from NMR and the percolation threshold in the barrier distribution obtaine d from conductivity are a function of the composition of the glass.