ETHYNETHIOL-BASED POLYENEPOLYSULFIDES FROM ACETYLENE AND ELEMENTAL SULFUR: SYNTHESIS AND PROPERTIES

Abstract

Ethynethiol-based polysulfide polymers [C_{ssize 2}}H₂S _x ] (x = 1-6) have been synthesized by the reaction of sodium acetylides and elemental sulfur in liquid ammonia with the following hydrolysis of sodium ethynethiolates and spontaneous polymerization of ethynethiols thus formed. The polymers are brown powders (up to 87% sulfur content), possessing electroconducting (10⁻¹³–10⁻¹⁴ S · cm⁻¹), paramagnetic (10¹⁸ spin · g⁻¹) and redox properties. Application of the polymers as active cathode materials provides for a stable cycling of model lithium batteries.

∗ Now Sion Power Corporation.

Keywords:

• Acetylene
• elemental sulfur
• ethynethiol
• ethynehydropolysulfanes
• lithium battery
• polymers

Notes

∗ Now Sion Power Corporation.

^a Quenching with 10% aqueous solution of NH₄Cl (pH ∼ 4–5).

^b Quenching with 10% aqueous solution of NH₄Cl and 10% aqueous solution of HCl (pH ∼ 2–3).

∗Relative thermodynamic stability of isomers 2 and 3 evaluated by HF/6-31G(d,p) method (Yu. L. Frolov et al.) indicates a higher stability of the structure 3 (these results will be published separately).