Protected bis(hydroxyorganyl) polysulfides as modifiers of Li/S battery electrolyte

The protected bis(hydroxyorganyl) polysulfides synthesized have been tested as modifiers of electrolyte of lithium-sulfur rechargeable batteries. The best result (35% increase of the battery capacity at the 50th cycle) was attained using 5 wt.% of 2,2,12,12-tetramethyl-4,10-diphenyl-3,11-dioxa-6,7,8-trithia-2,12-disilatridecane. Bis(hydroxyorganyl) polysulfides protected at the hydroxyl group have been synthesized for the first time by the reaction of oxiranes with sodium polysulfide (ethanol, NaHCO3, 12 h, 20-25 °C) in yield 21-87%. For the hydroxyl protection in the hydroxy polysulfides, the acetal, tri(methyl)silyloxy or tri(ethoxy)silyl protecting groups were employed.