Benzene-based polyorganodisulfide cathode materials for secondary lithium batteries

A novel kind of benzene-based organodisulfide, 5,8-dihydro-1H,4H-2,3,6,7-tetrathia-anthracene (DTTA) and its homopolymer, poly(5,8-dihydro-1H,4H-2,3,6,7-tetrathia-anthracene) (PDTTA) were designed, synthesized and presented as a cathode material for high-energy secondary lithium batteries. The polyorganodisulfides were characterized by FT-IR, XPS and elemental analysis. The designed system has many advantages, such as high theoretical charge density (ca. 471 mAh/g), fast redox process and enhanced cycling stability, which are due to the intramolecular electrocatalytic effect of polyphenyl chain and the intramolecular cleavage–recombination of the SS bond, respectively. The cyclic voltammetry test results proved the effect of this kind of electrocatalysis, and the charge–discharge experimental results showed that the polymer has the specific capacity of 422 mAh/g at 2nd cycle and 170 mAh/g at the 44th cycle.