The spin-lattice relaxation time of 7Li was measured at 77 to 680K. The data for higher temperatures were explained in terms of a relaxation mechanism for the diffusive motion of Li+ ion defects. The activation energy for the diffusion of Li+ was estimated to have a value of 0.08eV. From an analysis which was based upon the fluctuating field model, with diffusion of Li+ defects, the predominant mechanism of spin-lattice relaxation in LiCoO2 was expected to be quadrupole interaction, in the high-temperature region.
NMR Investigation on the Motion of Li+ Defects in LiCoO2 and LiNiO2. K.Nakamura, M.Yamamoto, K.Okamura, Y.Michihiro, I.Nakabayashi, T.Kanashiro: Solid State Ionics, 1999, 121[1-4], 301-6