Li intercalation across and along the van der Waals surfaces of MoS 2(0001)

Abstract

During Li deposition on single crystals of MoS 2 at RT, Li is intercalated into MoS 2 while two reactions take place: (a) an intercalation reaction according to the rigid band model, (b) an intercalation reaction accompanied by a phase transition 2H → 1T. The latter reaction dominates during Li intercalation across the van der Waals planes, while it is negligible and the first reaction prevails when (i) Li is intercalated along the van der Waals planes, (ii) the substrate temperature is elevated, and (iii) the Li deposition flux is relatively low. A relation of the minimum flux of Li deposition, at a certain temperature, across the van der Waals planes of MoS 2 necessary to prevent the phase transition and to dominate the rigid band intercalation reaction, is given as a function of the distance between successive molecular layers and the diffusion coefficient of Li.