Elemental sulfur-molybdenum disulfide composites for high-performance cathodes for Li–S batteries: the impact of interfacial structures on electrocatalytic anchoring of polysulfides

Enhanced cathodes for Li–S batteries with sulfur-MoS2 composites demonstrated recently are capable to extend cycle lifetimes up to 1000 cycles with 0.07% capacity decay per cycle and deliver reversible capacity up to 500 mAh/g at 5C. To understand the origins of such remarkable performance, we investigated in-depth the cathode structures and their transformations during cycling at various scales down to the atomic level. We show that 3D interfacial structures involving mechanically activated defective 2H-MoS2 particulates and aggregated conducting nanocarbons play a critical role in enabling to maintain cathode integrity, electrocatalytically bind Li2Sx polysulfides, and effectively reduce charge transfer resistance.