Lithium polymer battery with high energy density

Polymer cathode materials based on organosulfur compounds are developed for lithium rechargeable batteries with high energy density. Making a well‐mixed composite with a conducting polymer polyaniline (PAn) accelerates slow redox reactions of organosulfur compounds such as 2,5‐dimercapto‐1,3,4‐thiadiazole (DMcT). Using a copper cathode current collector, battery performances of the DMcT/PAn composite cathode are significantly improved due to a formation of a complex between DMcT and a copper ion: discharge capacity exceeding 225 Ah/kg‐cathode and cyclability more than 500 charge‐discharge cycles being achieved. Furthermore, addition of elemental sulfur (S8) to the composite further augments the discharge capacity of the composite cathode to more than 500 Ah/kg‐cathode.