Electrochemical Behavior Promotion of Polysulfides by Cobalt Selenide/Carbon Cloth Interlayer in Lithium−Sulfur Batteries

Abstract Lithium−sulfur batteries have been regarded as the next generation of competitive batteries because of their high theoretical capacity and energy density. However, the commercial development of lithium−sulfur batteries is restricted by the shuttle action of polysulfides and volumetric expansion of sulfur. Herein, we developed cobalt selenide/carbon cloth composites (CoSe 2 /CC) as the interlayer. CoSe 2 can not only limit the shuttling of polysulfides by Co−S bonds and accelerate the catalytic conversion kinetics of sulfur chemistry, but also increases the electrical conductivity of materials, leading to an excellent cycle stability. As a result, the cell with CoSe 2 /CC interlayer has a high initial capacity of 1420 mAh g −1 at 0.1 C and keeps high‐capacity retention of 596 mAh g −1 after 500 cycles at 1 C rate (70 %). Subsequent electrochemical tests show that CoSe 2 /CC enhance the electrochemical behavior of the polysulfides. Therefore, the hierarchical CoSe 2 /CC composites have promising application potential in lithium−sulfur batteries.