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 5wt.% 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 ...