Application of Polypropylene Separator Coated with Molybdenum Disulfide in Lithium Sulfur Batteries

A strategy was reported to obtain high capacity with long cycle life by introducing a molybdenum disulfide (MoS₂) coating on the separator. MoS₂ which was synthesized by a facile, one-pot hydrothermal method was coated on the separator by simple pumping filtration without any binder to inhibit the polysulfide shuttling effect. The morphology and physical property of MoS₂ and the separator coated with MoS₂ were characterized by SEM、XRD and BET. The electrochemical performances of lithium sulfur batteries(Li-S batteries) were studied by electrochemical workstation and battery test station. In spite of the use of a simple sulfur-carbon black mixture as cathode, the Li-S battery with a MoS₂-coated separator offered outstanding performances with an initial capacity of 1 010 mA·h/g and 432 mA·h/g after 150 cycles at 400 mA/g. In the same conditions, the Li-S battery with a Celgard separator offered performances with an initial capacity of 816 mA·h/g and 297 mA·h/g after 150 cycles at 400 mA/g. The improved results could be owned to the MoS₂ coating, which not only reduced the battery resistance but also blocked the diffusion of soluble polysulfides avoiding shuttle effect during cycling.