Photo-oxidation of an organosulfur for photo-charging of lithium-ion batteries

Abstract

Abstract Polymers of organosulfur with S-S bonds are potential cathode materials for high-capacity lithium-ion batteries, and the photo-oxidation of organosulfurs can be applied in the future to the photo-charging of batteries. Herein, we present the photo-oxidation of dithiobiuret (DTB), a simple organosulfur molecule with two neighbouring tautomeric thiol/thione groups (-SH/>C=S) that can form a disulfide (S-S) bond by reversible intramolecular oxidative cyclization. Aqueous solutions of DTB with different pH values were irradiated by visible light from a halogen lamp. Photo-oxidation was confirmed by ultraviolet (UV) absorption spectroscopy, on comparison of the UV absorption spectra of DTB and chemically oxidized DTB. The rate of photo-oxidation depended on the pH of the DTB solution, and the highest photo-oxidation rate of ∼ 2.8 × 10−3 min.−1 was observed at a pH of ∼ 3.1.