Syntheses and Electrochemical Properties of TEMPO Radical Substituted Silicones: Active Material for Organic Radical Batteries

A silicone-based radical polymer 2 was synthesized by hydrosilylation of PMHS with 4-allyl-2,2,6,6-tetramethylpiperidine-N-oxyl ether 1 in the presence of a platinum- or rhodium-catalyst. A reversible redox peak of 2 at 3.56 V (vs. Li/Li(+)) was observed by CV measurements. A coin-shaped cell of 2 shows a discharge capacity of 46 mAh . g(-1), which is 47% of the theoretical capacity of 2 (98 mAh . g(-1)). A directly TEMPO-substituted silicone, poly[methyl(2,2,6,6-tetramethylpiperidine-N-oxyl-4-oxyl)siloxane] 3 was also obtained by rhodium-catalyzed dehydrogenative alcoholysis of PMHS with TEMPO-OH. The coin-shaped cell of 3 shows a discharge capacity of 80 mAh . g(-1), which is 69% of the theoretical capacity of 3 (116 mAh . g(-1)).