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

Abstract

Lithium-intercalated SnS2 compounds have been studied with 6,7Li and 119Sn solid state NMR spectroscopy addressing the location of the insertion sites of the lithium. The central transition in the 7Li 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. 1H and 7Li decoupling experiments with 6Li NMR detection as well as the narrowing effect of magic angle spinning on the 7Li NMR line width indicate the presence of dipolar interactions. Temperature dependent 7Li NMR spin−lattice relaxation times reveal a decrease in activation energy for lithium motion at higher lithium contents. 119Sn spectra revealed additional peaks shifted downfield from the Sn(IV) resonance. 119Sn 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 interlayer space. A mechanism describing the lithium insertion process is derived.

Solid-state Li NMR with applications to the translational dynamics in ion conductors

“…This behavior is not that expected for one-, two-, or three-dimensional diffusion and was ascribed to correlated diffusion effects [336]. 6 Li and 7 Li NMR studies on the closely related compounds in the system Li x SnS 2 were also reported [339].…”

“…Some emphasis is put on trying to separate dipolar and quadrupolar contributions. The use of MAS, isotopic enrichment, or other means in order to achieve heteronuclear [339] or homonuclear Li decoupling is not discussed in the present section. Most of the effects discussed in the present section should also apply to 6 Li.…”

Lithium dynamics in molybdenum disulfide intercalation compounds studied by nuclear magnetic resonance

“…Additionally, the study of the dynamics of the species intercalated in layered materials constitutes one interesting problem in the field of solid-state physics. A number of recent studies have been addressed to the arrangements and the dynamics of species confined in low-dimensional spaces [10][11][12][13][14][15][16][17].…”

Structural Characterization and Electrochemical Reactions with Lithium of Cu2CoTixSn3-xS8 Solid Solutions

“…The known host solids containing either the group 4 or group 14 elements that show good lithium insertion properties possess a wide structural diversity, having in common the presence of a large number of interconnected empty sites available for the diffusion and location of lithium ions. They span from layered solids, such as the 1T-binary dichalcogenides TiS 2 − and SnS 2 − to strictly three-dimensional lattices. The latter are represented by spinel-related solids, which include the cation-deficient tin-containing thiospinels In 16 Sn 4 S 32 , , and rhodostannite-type Cu 3.31 GeFe 4 Sn 12 S 32 , as well as the titanium compound Cu x Ti 2 S 4 . − …”