Redox-active radical polymers for rapid charge-storage and -transport

Radical polymers bearing a high density of unpaired electrons in a pendant, non-conjugated fashion on each repeating unit provided a rapid, reversible, and quantitative redox behavior in an electrode form. Careful selection of radicals (TEMPO, galvinoxyl, and nitronylnitroxide, etc.) produced remarkably stable p- and n-type redox couples, which lead to the totally organic-based rechargeable batteries. The power-rate performance of these cells was excellent (360 C rate, 10 sec charge/discharge), as a result of the simple, rapid redox process of the organic radical moieties with no associated structural change in the amorphous polymer layer. Organic polymer-based electrodes are amenable to roll-to-roll or inkjet processing, which allowed the fabrication of a flexible, paper-like, and transparent rechargeable energy-storage device, which could be embedded in radio-frequency identification tags, smart cards and electronic paper.