A Pitaya-Like Co-800@KJ Nanocomposite as Separator Coating for High-Performance Lithium-Sulfur Battery

Lithium-sulfur (Li-S) batteries serve as an important candidate for next-generation high energy secondary batteries due to their high specific capacity, low cost, and environmental friendliness. However, the fast capacity fading induced by the polysulfide dissolution and subsequent shuttle effect hinders the application of Li-S batteries. Herein, a "pitaya"-like Co/C composite is prepared by a simple, rapid, and practical method and applied to Li-S battery coating. A Co-800@KJ-modified functional separator is constructed to improve the long-term cycle stability and rate capability of the pure sulfur cathode. Recessed depositions of Co particles and porous carbon effectively adsorb polysulfide by chemical anchoring and physical immobilization, respectively. Therefore, a stable long-term cycle ability of 620.5 mAh g(-1) after 500 cycles at 0.3 C is realized. Meanwhile, Co embedded in the pores has abundant polysulfide adsorption and catalytic sites, so that the battery also has a capacity of 467.1 mAh g(-1) at 4.0 C.