Aprotic and Protic Ionic Liquids as Electrolytes for Organic Radical Polymers

Abstract

In this study we systematically investigated the impact of aprotic and protic ionic liquids on the electrochemical behavior of poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA) based electrodes. We showed that the use of aprotic ILs based on the FSI− anion enables the realization of electrodes able to display high capacity, good capacity retention at high current density (42% at 50 C), low self-discharge and high stability during float tests. We also reported, for the first time, that it is possible to successfully use PTMA-based electrodes in combination with PILs. We showed that the PTMA electrodes display good capacity but a limited cycling stability in these ionic liquids. This investigation confirms that ionic liquids are very interesting candidates for the realization of high performance PTMA-based electrodes. A deeper understanding of the interactions taking place between ionic liquids and organic active materials will be required to finely tune the properties of these promising electrolytes for an application in organic radical polymer-based energy storage systems.