Diffusion-induced super(7)Li NMR relaxation of layer-structured tin disulphide - Li diffusion along the buried interfaces in Li sub(0.17)SnS sub(2)

super(7)Li NMR relaxation has been used to study lithium-ion diffusion in layer-structured SnS sub(2). Keeping the Li intercalation degree in Li sub(x)SnS sub(2) below x = 0.49, the Li ions preferentially occupy sites in the van der Waals gap between the SnS sub(2) sheets. In contrast to conventional NMR spin-lattice relaxation (SLR) rate measurements in the laboratory frame of reference, which are sensitive to rather fast Li exchange processes, with the help of spin-locking SLR NMR slower Li motions were extracted from characteristic diffusion-induced rate peaks. The latter contain information on both Li+ activation energies E sub(a) and Li ion jump rates [tau] super(-1) characterizing the elementary steps of Li+ hopping. Our results point to two different diffusion processes (E sub(a)(I) = 0.38 eV; E sub(a)(II) = 0.28 eV), a slower and a faster one, observable directly after chemical Li insertion. Interestingly, the diffusion behaviour irreversibly changes when the sample has been exposed to temperatures as high as 573 K. Diffusion-induced NMR rates and corresponding line shapes are discussed with respect to an inhomogenous distribution of Li ions in SnS sub(2), which seems to be present directly after Li intercalation.