In Situ Laminated Separator Using Nitrogen-Sulfur Codoped Two-Dimensional Carbon Material to Anchor Polysulfides for High-Performance Li-S Batteries

The high theoretical specific capacity of lithium-sulfur battery is regarded as a promising candidate for next generation battery systems. However, polysulfide shuttle is known as a major issue of accelerating capacity fading and corroding the metal lithium anode, which impedes its commercial application. Here, a nitrogen-sulfur codoped two-dimensional carbon material is synthesized using a novel template method by pyrolyzing chemical adsorption of montmorillonite and methylene blue. The microstructure and morphologies of the synthesized two-dimensional carbon materials are fully characterized using SEM, TEM, XRD, and Raman techniques. The experiment results indicate that the carbon material shows a typical graphene structure. The micro/mesoporous and heteroatoms codoped structure of the synthesized carbon material exhibits excellent performance in electronic conductivity and polysulfides confinement. The functional separator laminated with the binder-free carbon material endows the battery outstanding electrochemical and rate performances. The excellent rate performance is discovered a capacity of 828 mAh g(-1) at 4 C with good reversibility. The battery presents a high initial discharge specific capacity of 1049 mAh g(-1) with good capacity retention of 690 mAh g(-1) after 500 cycles at 1 C. Consequently, the separator laminated with the nitrogen-sulfur codoped graphene is promising for the construction of high performance Li-Sd batteries.