Lithium–Sulfur Batteries with High Rate and Cycle Performance by using Multilayered Separators coated with Ketjen Black

Abstract The commercialization of lithium–sulfur (Li–S) batteries remains challenging due to their poor rate performance and low cycle stability, which can be partly attributed to the insulation of sulfur/lithium sulfide and the migration of polysulfides from the sulfur cathode to the anode. While much effort has been devoted to designing the structure of sulfur cathodes for suppressing the dissolution of polysulfides, relatively little emphasis has been placed on modifying the separator. In this work, we demonstrated an approach to modify the pristine separator by coating a Ketjen Black (KB) layer, and we mainly investigated the impact of different layers of modified‐separator on electrochemical performance of Li–S battery. With the three layers of modified‐separator, the battery possess a high initial discharge capacity of 1430 mAh g −1 at 0.1 C and deliver discharge capacities of 770 mAh g −1 and 522 mAh g −1 after 150 cycles, respectively, at high rate of 2 C and 4 C. Moreover, when the rate is increased to 6 C, the cell can also deliver a discharge capacity of 300 mAh g −1 . These encouraging electrochemical results highlight the excellent rate capability and high cycle stability of Li–S battery, which could be attributed to high electron conductivity of the KB layer and the new cell configuration. This facile approach to restrain the shuttle effect of polysulfides makes further progress in obtaining enhanced performance of Li–S battery.