Ethynedithiol‐based polyeneoligosulfides as active cathode materials for lithium‐sulfur batteries

Abstract

Abstract Ethynedithiol‐based polyeneoligosulfides have been synthesized in 96% yield by the reaction of sodium acetylides (HCCNa, NaCCSNa) and elemental sulfur through the NaC sp bond in liquid ammonia with the following spontaneous polymerization of ethynedithiols (HSCCSH) formed by the hydrolysis. The polyeneoligosulfides synthesized are brown powders (up to 77% sulfur content, mp 128–184°C), partially soluble in organic solvents. They are high‐resistance semiconductors (10 −13 to 10 −14 S cm −1 ), possess paramagnetic (10 17 to 10 18 spin g −1 ) and redox properties. The oligosulfides obtained, being redox systems capable of reversible redox processes, provide high values of discharge capacity (345–720 mA h g −1 ) of rechargeable lithium‐sulfur batteries. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008