Quaternary Polymer Electrolytes Containing an Ionic Liquid and a Ceramic Filler

In this work, the individual and combined effects of an ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide and ceramic filler silicon dioxide on the thermal and electrochemical properties of poly(ethylene oxide) electrolytes have been investigated. The electrolyte containing both components has the lowest glass transition (-60 degrees C) and melting temperatures (27 degrees C), the highest conductivity at any investigated temperature, and the highest limiting current density (at 40 degrees C). This solid polymer electrolyte also exhibits the best long-term cycling performance in Li/LiFePO4 cells.