  The commercial realization of lithium-sulfur (Li-S) batteries is obstructed
because of rapid capacity fading due to lithium polysulfides (LiPSs)
dissolution into the electrolyte. In order to enhance the efficiency and
performance of the Li-S batteries, the transition metal dichalcogenides are
reported as promising anchoring materials (AMs) as they could strongly adsorb
and effectively suppress the migration of the polysulfides species. Herein, we
used first-principles based density functional theory (DFT) calculations to
investigate the interactions between AMs such as tungsten dichalcogenides, WX2
(X=S and Se) and the LiPSs. The LiPSs binding behavior of WS2 and WSe2 are
found to be quite similar. The calculated adsorption energies of LiPS species
indicate that the WX2 possesses moderate binding strength and the binding is
facilitated via charge transfer from the polysulfides to the AM. We observe
elongation of intramolecular Li-S bonds in LiPS upon their adsorption onto the
WX2, however, chemical structures of LiPSs are preserved without decomposition.
The calculated density of states indicates the LiPS adsorbed WX2 systems
exhibits semiconducting behavior with a slightly lower bandgap compared to the
pristine WX2. Overall, our simulation results provide detailed insight into the
behavior of WX2 as AMs to suppress the LiPSs migration and henceforth paves the
way towards the development of high-performance Li-S batteries.
