CHARACTERIZATION AND PERFORMANCE OF ORGANOSULFUR CATHODES FOR SECONDARY LITHIUM CELLS: COMPOSITES OF ORGANOSULFUR, CONDUCTING POLYMER, AND COPPER ION

摘要

The use of a new cathode material based on a composite of an organosulfur compound, 2,5-dimercapto-1,3,4-thiadiazole (DMcT), poly(aniline), and catalytic amounts of copper ion in secondary lithium cells is reported. Cathode-limited cells were discharged at 300 A h per kg-cathode for ca. 10 cycles, at 260 A h per kg-cathode for at least ca. 80 cycles, or at 170 A h per kg-cathode for ca. 130 cycles. Furthermore, after failure of these cells replacement of the lithium anode restores the original capacity. Vibrational spectroscopy of the copper/DMcT system indicates that addition of Cu(II) oxidizes and complexes DMcT and thus allows more solvent to be evaporated from the films. Furthermore, we find that the redox processes in the film are greatly stabilized by copper ion, likely due to a mixture of catalytic and conductive effects.