To address the ever-increasing demand for portable energy sources, Li-ion batteries (LIBs) and electrochemical capacitors are considered as the most mature technologies. LIBs are usually implemented wherever the energy density is the key parameter rather than the power density. Oppositely the electrochemical capacitors offer considerably higher power densities but at the expense of their energy densities. In between these technologies, there is still some room for a technology balancing the power and the energy densities. When it comes to fill the gap between LIBs and electrochemical capacitors, organic radical materials are currently considered as a promising class of electroactive compounds. One of the most studied of this class is the poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (PTMA), a polymer bearing stable nitroxide radicals as side groups. Yet, this polymer suffers from its solubility in standard commercial electrolytes and from its electric insulating behavior. To overcome these limitations, we developed original grafting strategies yielding composite materials based on carbon nanotubes and immobilized electroactive polymer chains. These strategies are not only affording a mean to suppress the solubilization of the active material but also permit high power performances thanks to the intimate contact of PTMA with the MWCNT conductive network. Furthermore, with respect to common PTMA/conductive carbon blends, our MWCNT-g-PTMA materials display superior power performances owing to the enhanced charge transfer and current collection. That is, the carbon loading can be lowered while maintaining the same rate performances. The success of our strategies highlights the benefits of a precise distribution of the active material around the conducting network thanks to our designed core-shell morphology.

Electroactive polymer/carbon nanotubes hybrid materials for energy storage synthesized via grafting approaches

254th National Meeting (2017)

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