Structure and Dynamics of Lithium-Intercalated SnS2. 6,7Li and 119Sn Solid State NMR

Lithium-intercalated SnS 2 compounds have been studied with 6,7 Li and 119 Sn solid state NMR spectroscopy addressing the location of the insertion sites of the lithium. The central transition in the 7 Li NMR spectra can be decomposed into two components giving rise to different quadrupole coupling constants and may be assigned to lithium in octahedral and tetrahedral lattice sites. 1 H and 7 Li decoupling experiments with 6 Li NMR detection as well as the narrowing effect of magic angle spinning on the 7 Li NMR line width indicate the presence of dipolar interactions. Temperature dependent 7 Li NMR spin−lattice relaxation times reveal a decrease in activation energy for lithium motion at higher lithium contents. 119 Sn spectra revealed additional peaks shifted downfield from the Sn(IV) resonance. 119 Sn spin−lattice relaxation times and the total number of observable tin nuclei indicate that with increasing lithium content interactions with delocalized electrons may be present. In summary, the NMR results show that the lithium is preferentially inserted in the inter layer space. A mechanism describing the lithium insertion process is derived.