capacity of 1675 mAh g −1 . [11][12][13] Despite their great promises, the commercialization of LSBs has been severely limited by several critical issues. They include: i) the inherently low electrical conductivity of S, i.e., 5 × 10 −30 S cm −1 at room temperature; ii) the formation of polysulfides leading to high overpotentials and low utilization of active materials [14] ; iii) the large volume expansion of ≈80% during lithiation, causing large mechanical stresses to build up on the cathode [15] ; and iv) the dissolution of intermediate polysulfide products in a shuttling effect, resulting in fast capacity degradation and poor Coulombic efficiencies. [16] To address the aforementioned issues, extensive research efforts have been devoted to developing rationally designed cathode materials, [17] protection of lithium anodes, [18] and modification of electrolytes [19][20][21] in LSBs. One effective strategy is to constrain S 8 or polysulfides within the cathode cavities so as to maintain the mechanical and electrical integrity of cathodes using unique structures, such as mesoporous carbon matrix/S, [22] activated porous carbon nanofiber/S, [14] activated carbon nanotube (CNT)/S, [23] hollow carbon nanosphere/S, [24] and metalorganic framework/S composites. [25] Although these porous hosts have been proven to suppress the shuttling effect, their large fractions of 30-60 wt% of the cathode inevitably reduce the energy densities of battery, compared with the neat S/ carbon black cathode, prompting urgent development of new strategies. More recently, separators coated with carbon materials, such as graphene oxide (GO) [26] and microporous carbon, [27] have been successfully introduced in LSBs to intercept the migration of polysulfides and reuse the adsorbed active material. [28] However, the interactions between the carbon materials and polysulfides are often too weak to effectively entrap and hold the polysulfides for their recycling. Therefore, understanding the interfacial interaction mechanisms and identifying appropriate coupling materials to enhance the interactions with polysulfides are required.Suitable coupling materials for polysulfide species should have two unique functional features. i) They should possess moderate binding energies with polysulfides in the range of 0.8-2.0 eV because too strong a binding energy over 2.0 eV softens the internal LiS bonds, leading to decomposition 2D layer-structured materials are considered a promising candidate as a coupling material in lithium sulfur batteries (LSBs) due to their high surfacevolume ratio and abundant active binding sites, which can efficiently mitigate shuttling of soluble polysulfides. Herein, an electrochemical Li intercalation and exfoliation strategy is used to prepare 2D Sb 2 S 3 nanosheets (SSNSs), which are incorporated onto a separator in LSBs as a new 2D coupling material for the first time. The cells containing a rationally designed separator which is coated with an SSNS/carbon nanotube (CNT) coupling layer deliver a much improved specific ca...
