Development of polymer-based lithium secondary battery

Novel polymer composites based on polydisulfide compounds are developed as a high energy density cathode material for lithium rechargeable batteries. A polymer composite composed of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) and conducting polymer polyaniline (PAn) on a copper current collector provides high charge density exceeding 225Ah/kg-cathode with average discharge voltage at 3.4V. The composite cathode showed excellent rate capability and cyclability (>500 cycles). Surface analysis and electrochemical studies indicate that a DMcT-Cu complex plays an important role in the observed improvement of the battery performances with a copper current collector. Large increase in the charge density to 550Ah/kg-cathode is achieved by adding elemental sulfur (S8) to the DMcT/PAn composite cathode.