Poly(vinyldibenzothiophenesulfone): Its Redox Capability at Very Negative Potential Toward an All-Organic Rechargeable Device with High-Energy Density

Dibenzothiophenesulfone undergoes a two-electron reduction in a single step at a very negative potential of -1.8 V (versus Ag/AgCl) in organic electrolytes, due to the electron-withdrawing sulfone group and the stability of the resulting dianion. The heterogeneous electron-transfer rate constant for the reduction is approximately 10^-1cm s^-1, which is significantly faster than most redox-active species. The results presented herein suggest that dibenzothiophenesulfone is a potential candidate for use as an anode-active material with high-energy density. In addition, radical polymerization of vinyldibenzothiophenesulfone yielded poly(vinyldibenzothiophenesulfone) with a high molecular weight. A rechargeable device is fabricated with only organic compounds; poly(vinyldibenzothiophenesulfone) as the anode, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-substituted poly(methacrylate) as the cathode, and tetraethylammonium salt and organic solvent as the electrolyte. This device yields a maximum output voltage of 2.6 V in these organic devices, and the active component of the anode displays a very high-energy density of >500 mWh g^-1.