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 7.43 mg cm⁻² and low E/S ratio of 5 mL g⁻¹). The rational design of multifunctional edge-rich 2D TMDs provides fresh insights for developing stable LSBs.