Density-functional study of LixMoS2 intercalates (0 ⩽ x ⩽ 1)

The stability of Lithium intercalated 2H- and 1T allotropes of Molybdenum disulfide (LixMoS2) is studied within a density-functional theory framework as function of the Li content (x) and the intercalation sites. Octahedral coordination of Li interstitials in the van der Waals gap is found as the most favorite for both allotropes. The critical content of Lithium, required for the initialization of a 2H → 1T phase transition is estimated to x ≈ 0.4. For smaller Li contents the hexagonal 2H crystal structure is not changed, while 1T-LixMoS2 compounds adopt a monoclinic lattice. All allotropic forms of LixMoS2 - excluding the monoclinic Li1.0MoS2 structure - show metallic-like character. The monoclinic Li1.0MoS2 is a semiconductor with a band gap of 1.1 eV. Finally, the influence of Li intercalation on the stability of multiwalled MoS2 nanotubes is discussed within a phenomenological model.

Highlights► Lithium intercalated MoS2 may occur in a few allotropes. ► A manifold of LixMoS2 compounds is studied by DFT method. ► Relative stability of LixMoS2 allotropes depends on the Lithium content x. ► Stability of MoS2 nanotubes is not interfered by expansion upon Li intercalation.