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

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 (CoSe2/CC) as the interlayer. CoSe2 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 CoSe2/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 CoSe2/CC enhance the electrochemical behavior of the polysulfides. Therefore, the hierarchical CoSe2/CC composites have promising application potential in lithium-sulfur batteries.