Edge Engineering in 2D Molybdenum Disulfide: Simultaneous Regulation of Lithium and Polysulfides for Stable Lithium-Sulfur Batteries

Polysulfides shuttling and lithium dendrite growth are two challenges confronting lithium-sulfur batteries (LSBs). Herein, edge engineering of 2D transition metal dichalcogenides (TMDs) is proposed to simultaneously address these two issues. First, utilizing MoS2 as a model material, theoretical calculations demonstrate the strong binding affinity of polysulfides to molybdenum edges and the robust electrovalent bonds between Li+ and sulfur edges, thus predicting the multifunctional regulation capability of edge-rich MoS2. Holey atomically thin MoS2-constructed nanobrushes (HATM-NBs) are then prepared by a polar functionality-assisted anchoring strategy. The functionality anchoring effectively inhibits longitudinal growth of 2D MoS2 and more impressively facilitates formation of plentiful in-plane nanopores due to the fast nucleation and growth. Spectroscopy and electrochemical techniques verify the superior adsorption/catalytic conversion of polysulfides by Mo edges and therefore accelerated redox reactions. The sulfur edge-rich nanobrush structure promotes good contact with the lithium metal anode, homogenized Li+ flux, and thus uniform lithium plating/stripping. A fabricated laminate cell with ultrathin HATM-NBs-coated separator demonstrates superior electrochemical performances even under harsh test conditions (high sulfur loading of 7.43mgcm(-2) and low E/S ratio of 5mLg(-1)). The rational design of multifunctional edge-rich 2D TMDs provides fresh insights for developing stable LSBs.