Interfacial "Double-Terminal Binding Sites" Catalysts Synergistically Boosting the Electrocatalytic Li 2 S Redox for Durable Lithium-Sulfur Batteries.

Catalytic conversion of polysulfides emerges as a promising approach to improve the kinetics and mitigate polysulfide shuttling in lithium-sulfur (Li-S) batteries, especially under conditions of high sulfur loading and lean electrolyte. Herein, we present a separator architecture that incorporates double-terminal binding (DTB) sites within a nitrogen-doped carbon framework, consisting of polar Co 0.85 Se and Co clusters (Co/Co 0.85 Se@NC), to enhance the durability of Li-S batteries. The uniformly dispersed clusters of polar Co 0.85 Se and Co offer abundant active sites for lithium polysulfides (LiPSs), enabling efficient LiPS conversion while also serving as anchors through a combination of chemical interactions. Density functional theory calculations, along with in situ Raman and X-ray diffraction characterizations, reveal that the DTB effect strengthens the binding energy to polysulfides and lowers the energy barriers of polysulfide redox reactions. Li-S batteries utilizing the Co/Co 0.85 Se@NC-modified separator demonstrate exceptional cycling stability (0.042% per cycle over 1000 cycles at 2 C) and rate capability (849 mAh g -1 at 3 C), as well as deliver an impressive areal capacity of 10.0 mAh cm -2 even in challenging conditions with a high sulfur loading (10.7 mg cm -2 ) and lean electrolyte environments (5.8 μL mg -1 ). The DTB site strategy offers valuable insights into the development of high-performance Li-S batteries.