We present in this study a theoretical investigation of the collision of Li with the MX2 surface (MoSe2 or WS2) by employing the Born-Oppenheimer molecular dynamics (MD) approach. In each trajectory, atomic Li is fired toward the two-dimensional monolayer with an inletting kinetic energy of 0.2 eV or 2.0 eV and a chosen striking angle. In total, 84 MD trajectories are analyzed. We observe that Li has a high tendency to migrate on WS2 in most investigated cases (20/21 cases at 0.2 eV inletting kinetic energy and 21/21 cases at 2.0 eV inletting kinetic energy), while the migration probability on MoSe2 is much lower (only 5/21 cases with the inletting kinetic energy of 0.2 eV and 15/21 cases with the inletting kinetic energy of 2.0 eV). Interestingly, our finding shows that the migration probability does not depend on the binding energies of Li-MoSe2 (1.61 eV) and Li-WS2 (1.77 eV), but it is in good agreement with the nudged-elastic-band prediction of migration barriers. In fact, it is the intensity of elastic vibration of the transition metal dichalcogenide layer that plays a very significant role in the migration of Li. During the collision process, Li is able to absorb energy from the layer vibration to jump out from one X-X-X trap to another. Consequently, with the assistance from intensive vibration of WS2, Li would possess higher migration probability on the layer surface. Finally, electronic structure analysis on various interacting Li-MX2 configurations is performed. From Bader charge estimation, we observe that WS2 tends to establish more charge transferability with Li. Moreover, when Li approaches closer to the S/Se layer, the hybridization of Li-2s and Mo-4d (or W-5d) orbitals results in a magnetic moment (up to ∼1 μB).
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry