Synthesis and Characterization of a Molecularly Designed High‐Performance Organodisulfide as Cathode Material for Lithium Batteries

Abstract

Abstract An innovative organodisulfide compound, 2,3,4,6,8,9,10,12‐Octathia biscyclopenta[b,c]‐5,11‐anthraquinone‐1,7‐dithione (TPQD), has been successfully designed, synthesized, and characterized as a cathode material for lithium batteries. A benzoquinone is introduced to coordinate with dithiolane through 1,4‐dithianes. The molecular structure, electrochemical performances, and the lithiation/delithiation mechanism of the TPQD cathode have been systematically investigated. TPQD can deliver an initial capacity of 251.7 mAh g −1 at a rate of C/10, which corresponds to the transfer of 4.7 electrons per formula. Highly reversible capacities and stable cyclic performances can be achieved at rates from C/10 to 5 C. Very interestingly, TPQD can retain a capacity of 120 mAh g −1 after 200 cycles at the 5 C rate, which is quite impressive for organodisulfide compounds. X‐ray absorption spectroscopy measurements and density functional theory calculation results suggest that such a high capacity is contributed by both O redox of the quinone group and the cleavage and recombination of the disulfide bond. Moreover, the extended π‐conjugation structure of the material, introduced by benzoquinone and dithiane, is beneficial for improving the high rate capability and cyclic stability. This study illustrates an innovative approach in designing new organodisulfide compounds with improved cyclability and rate capability as cathode materials for high performance lithium batteries.