Leakage currents and self-discharge of ionic liquid-based supercapacitors

• Published in: Journal of applied electrochemistry 2014-04, Vol.44 (4), p.491-496
• Main Authors: Soavi, Francesca, Arbizzani, Catia, Mastragostino, Marina
• Format: Article
• Language: English
• Subjects: Capacitors; Chemistry; Chemistry and Materials Science; Electric potential; Electrochemistry; Electrolytes; Electrolytic cells; Industrial Chemistry/Chemical Engineering; Leakage current; Leaks; Physical Chemistry; Research Article; Supercapacitors; Voltage
• ISSN: 0021-891X; 1572-8838
• DOI: 10.1007/s10800-013-0647-x

Ionic liquid (IL)-based supercapacitors have been widely demonstrated to outperform electrochemical double-layer capacitors (EDLCs) working with conventional organic electrolytes in terms of specific energy and operating voltage. Here, the results of a study on the leakage currents ( I leak ) and self-discharge energy loss factors (SDLF) of IL-based EDLCs at different cell voltages up to 3.2 V and at 30° and 60 °C are reported. Cells assembled with the N -butyl- N -methyl-pyrrolidinium bis(trifluoromethanesulfonyl) imide (PYR 14 TFSI) and N -methoxyethyl- N -methylpyrrolidinium bis(trifluoromethanesulfonyl)imide pure ILs and a mixture of PYR 14 TFSI and propylene carbonate (PC) 1 to 1 molar were tested. The results are compared to those achieved with EDLCs featuring the conventional 1 M tetraethyl ammonium tetrafluoroborate (Et 4 NBF 4 )-PC electrolyte. The study demonstrates that ILs provide I leak and SDLF that are lower than those obtained with the latter electrolyte, with PYR 14 TFSI allowing the lowest values.