Direct electrochemical sulfide oxidation to trisulfide and tetrasulfide reagents by in situ selective capturing

Polysulfides are important reagents for sulfur-based polymers and lithium–sulfur batteries, yet their conventional syntheses yield varying chain-length mixtures. Electrochemical sulfide oxidation is an energy-efficient alternative route that suffers from electrode passivation, low selectivity and soluble products. Here we develop an in situ selective capturing strategy during sulfide electrooxidation to produce only trisulfide and tetrasulfide without disulfide in the precipitate form. By tuning electrolytic conditions and capturing agents, we achieve selectivities up to 73% (trisulfide) and 82% (tetrasulfide). This chemoselectivity stems from strong interaction of di-anionic polysulfides to hydrophobic quaternary ammonium cations that redirects the oxidation pathway to high-purity trisulfides and tetrasulfides. These trisulfide and tetrasulfide reagents crosslink halides or epoxides and vulcanize polyvinyl chloride at ambient conditions with sulfur chain-length-dependent properties, enabling precise polysulfide chemistry for advanced chemicals and materials. The alternative text for this image may have been generated using AI.