Thiuram Monosulfide with Ultrahigh Redox Activity Triggered by Electrochemical Oxidation.

Abstract

Organosulfides are promising cathodes for lithium batteries but often suffer from sluggish kinetics and low cycle stability. Herein, we report an electron-deficient organosulfide (ED-OS), which is formed via electrochemical oxidation of thiuram monosulfide, a low-cost sustainable material. The ED structure of (dimethylcarbamothioyl)thio can stretch the electron cloud of the adjacent C═S bond forming an S radical and lead to the cleavage of the S-C bond on the other side forming another S radical. The two (dimethylcarbamothioyl)thio radicals can form S-S bonds individually with low energy barriers, which thus are easy to break and could accommodate lithium ions with ultrafast reaction kinetics. It exhibits an ultralong cyclability of over 8000 cycles with a low capacity-fade rate of 0.0038% per cycle at a high rate of 10C in a lithium cell. In addition, we demonstrate that the same electrochemical oxidation can be applied to other thiuram compounds. This work provides new opportunities in developing ultrahigh-redox-activity organic electrode materials which can be started as needed.