High temperature carbon–carbon supercapacitor using ionic liquid as electrolyte

This paper presents results about the electrochemical and cycling characterizations of a supercapacitor cell using a microporous activated carbon as the active material and N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) ionic liquid as the electrolyte. The microporous activated carbon exhibited a specific capacitance of 60 F g−1 measured from the three-electrode cyclic voltammetry experiments at 20 mV s−1 scan rate, with a maximum operating potential range of 4.5 V at 60 °C. A coin cell assembled with this microporous activated carbon and PYR14TFSI as the electrolyte was cycled for 40,000 cycles without any change of cell resistance (9 Ω cm2), at a voltage up to 3.5 V at 60 °C, demonstrating a high cycling stability as well as a high stable specific capacitance in this ionic liquid electrolyte. These high performances make now this type of supercapacitor suitable for high temperature applications (≥60 °C).