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 −1  cm 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 .