The motion of Li ions in the quasi 2-dimensional hexagonal and 3-dimensional cubic structures of the 2 modifications of the intercalation compound, LixTiS2, where x was between 0 and 1, was studied by means of nuclear magnetic relaxation spectroscopy. The 7Li spin-lattice relaxation times in the laboratory and rotating frames were measured at various frequencies and temperatures, and the results were interpreted in terms of dimensionality and correlation effects. Thus, it was shown that correlation effects which arose from Coulomb interactions for example could reduce the asymmetry of the temperature dependence of the diffusion-induced spin-lattice relaxation rate peak. Moreover, measurements of the frequency dependence of the spin-lattice relaxation rate permitted the examination of the dimensionality of the jump process. On the other hand, the spin-lattice relaxation rate in the cubic polymorph was independent of frequency on the high-temperature side of the peak; showing that, in this case, diffusion was 3-dimensional. For a given Li content, the activation energy for diffusion in the cubic modification was higher than that in the hexagonal modification.

W.Küchler, P.Heitjans, A.Payer, R.Schöllhorn: Solid State Ionics, 1994, 70-71, 434-8