Organosulfur polymer batteries with high energy density

The redox reaction of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) at the electrode surfaces is slow at room temperature and influenced strongly by the acidity of the solutions. However, this reaction can be accelerated when the electron-transfer reaction is coupled with that of polyaniline (PAn). PAn can be used as a molecular current collector for the insulating organosulfur compounds which are promising high capacity energy storage materials. The charge/discharge capability of a polymer composite cathode prepared from DMcT, PAn, 3-alkylcarboxylate-4-methylpyrrole and acetylene black has been investigated on different types of current collector, such as copper and porous carbon film, in a lithium-cell system with a gel-like polymer electrolyte. A battery assembled from the polymer composite cathode with a copper current collector provides a flat discharge potential difference from 3.4 to 2.8 V and high current capability (137–194 A/kg-cathode) without undue deterioration of the energy density. The battery can be charged up to 550 W h/kg-cathode within 1.25 h and reversibly discharged within 1.25 h.