New Composite Cathodes for Lithium Rechargeable Batteries

New organic composites based on thiol-compounds are developed as a cathode material for lithium batteries. A conducting polymer polyaniline (PAn) accelerates slow redox reactions of the organic sulfur compounds with multiple thiol groups, such as 2,5-dimercapto-1,3,4-thiadiazole (DMcT). A composite cathode composed of DMcT and PAn on a copper current collector provides high charge density exceeding 225Ah/kg-cathode and is capable of being charged and discharged at high rates with excellent cyclability (>500 cycles). Surface analysis and electrochemical studies indicate that a DMcT-Cu complex plays an important role in the observed battery performances of the composite on a copper current collector. Large increase in the charge density to 550Ah/kg-cathode is achieved by adding elemental sulfur (S 8 ) to the composite cathode.