High voltage electrochemical double layer capacitor containing mixtures of ionic liquids and organic carbonate as electrolytes

Using a mixture of PC/PYR(14)TFSI as electrolyte. EDLCs with an operative voltage of 3.5 V and ESR comparable with that of conventional electrolyte have been realized. The combination of high operative voltage and low ESR enable the realization of EDLCs with high energy and high power. Moreover, the use of PC/PYR(14)TFSI mixture also guarantees a remarkable cycling stability, as evidenced by a capacitance loss of only 5% after 100,000 cycles carried out at 3.5 V. (C) 2011 Elsevier B.V. All rights reserved.