New organodisulfide—polyaniline composite cathode for secondary lithium battery

Abstract

A new composite cathode used for high-energy density secondary lithium batteries is developed, which consists of 2,5-dimercapto-1,3,4-thiadiazole (organodisulfide), polyaniline, and gel electrolyte. Polyaniline works to promote the redox reaction of the organodisulfide in the composite electrode, providing the cyclic voltammogram showing a narrower peak-potential separation of 0.5 V between cathode and anode peaks. The lithium cell using the composite cathode and gel electrolyte based on acrylonitrile—methylacrylate copolymer has over 3.0 V cell voltage with 303 Wh kg −1 cathode energy density at a current density of 0.1 mA cm −2 at room temperature. In practice, a model cell with 80 μm thick lithium anode, 50 μm thick gel electrolyte, and 170 μm thick composite cathode is expected to deliver 220 Wh kg −1 cell energy density at 0.1 mA cm −2.