Controlled Synthesis of Sulfur-Rich Polymeric Selenium Sulfides as Promising Electrode Materials for Long-Life, High-Rate Lithium Metal Batteries

High-energy lithium/sulfur (Li/S) batteries still suffer from unsatisfactory cycle life and poor rate capability caused by the polysulfides shuttle and insulating nature of S cathodes. Here, we report our findings in the controlled synthesis of selenium (Se)-containing S-rich co-polymers of various compositions as novel cathode materials through a facile inverse vulcanization of S with selenium disulfide (SeS2) and 1,3-diisopropenylbenzene (DIB) as co-monomers. Nuclear magnetic resonance and X-ray photoelectron spectroscopy results show that divinyl functional groups of DIB were chemically cross-linked with S/SeS2 chain radicals through a ring-opening polymerization. The newly formed bonds of C–S, C–Se, and S–Se in novel S–SeS2–DIB co-polymers effectively alleviate the shuttle effects of polysulfides/polyselenides. Furthermore, various electrochemical techniques confirm the positive roles of Se-containing co-polymers in enhancing the electrode reaction kinetics and the formation of stable solid electrolyt...