Origin of Structural Transformation in Mono- and Bi-Layered Molybdenum Disulfide

Abstract

Mono- and multi-layered molybdenum disulfide (MoS2) is considered to be one of the next generation anode materials for rechargeable ion batteries. Structural transformation from trigonal prismatic (2H) to octahedral (1T) upon lithium or sodium intercalation has been in-situ observed experimentally using transmission electron microscope during studies of their electrochemical dynamics processes. In this work, we explored the fundamental mechanisms of this structural transformation in both mono- and bi-layered MoS2 using density functional theory. For the intercalated MoS2, the Li and Na donate their electrons to the MoS2. Based on the theoretical analysis, we confirmed that, for the first time, electron transfer is dominant in initiating this structural transformation, and the results provide an in-depth understanding of the transformation mechanism induced by the electron doping. The critical values of electron concentrations for this structural transformation are decreased with increasing the layer thickness.

Composition dependence of the charge-driven phase transition in group-VI transition metal dichalcogenides

“…In agreement with previous DFT studies, we find the H phase to be the ground state structure for all four materials 11,19,28,29,[53][54][55] . The total energy differences between this phase and both the T phase and the T mixed phase are given in Fig.…”

Rhenium doping induced structural transformation in mono-layered MoS2 with improved catalytic activity for hydrogen evolution reaction

“…Layered transition metal dichalcogenides (TMS2) have attracted extensive research interest due to their excellent electrical, chemical and optical properties [11,12]. Among these, monolayer molybdenum disulfides (MoS2) have been applied in rechargeable ion batteries, transistors and catalysts [13][14][15]. Its good catalytic activity and stability for HER make it one of the promising candidates to replace noble metals including ruthenium, iridium and platinum [16].…”

“…1. Sun et al [13] studied the origin of phase transformation between 2H-and 1T'-MoS2, and showed that electron doping destabilizes the crystal structure of the 2H-MoS2, thus causing its structural transformation into the 1T'-MoS2 phase. The 2H-MoS2 phase is the most common and stable crystal structure of MoS2 with a semiconducting character.…”

Electric field enhanced adsorption and diffusion of adatoms in MoS2 monolayer

“…As the Li/Mg/Al atoms are adsorbed on the MoS 2 , charge transfer from the atoms to the MoS 2 occurs [42,67]. The amount of charge transferred from the atoms will increase with the increase of strength of the electric field, and the difference in the charge transfer at the different sites will decrease with increasing strength of the electric field.…”