Lock of sulfur with carbon black and a three-dimensional graphene@carbon nanotubes coated separator for lithium-sulfur batteries

Abstract Three-dimensional graphene@carbon nanotube (G@CNT) composite was coated on polypropylene separator as an interlayer for high performance of lithium-sulfur batteries. In this study, the novel G@CNT nanotubes coated separator offers not only fast electron pathway for insulating sulfur, but also outstanding restriction of dissolving polysulfides. The heat impregnation of sulfur in carbon black also plays an auxiliary role on the cycling performance of the G@CNT interlayer assisted cathodes. As the dual sulfur locking strategy by heat impregnation and G@CNT interlayer, the prepared Li-S cells exhibited high rate capacity and sustainably enhanced cycling stability. Excellent cycling performance with a high capacity 935.1 mAh g −1 at 0.2C and 755.6 mAh g −1 at 1C after 200 cycles is achieved. Moreover, the cell delivers reversible discharge capacities up to 669.7 mAh g −1 and 555.1 mAh g −1 after 200 cycles even at 2C and 4C.