Comparison of the anodic behavior of aluminum current collectors in imide-based ionic liquids and consequences on the stability of high voltage supercapacitors

Kühnel R-S, Balducci A

Zusammenfassung

In this work, the influence of two common ionic liquid (IL) anions on the anodic stability of Al current collectors was studied. Namely, the Al corrosion/passivation process in N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) is compared to the one in N-butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (PYR 14FSI). It is shown, that Al slowly corrodes in PYR14FSI, while it is much better passivated in PYR14TFSI, although the ionic liquids were prepared in the same way. Float tests were carried out to illustrate the consequences of these different anodic stabilities of Al on the cycling stability of supercapacitors. Interestingly, when the chloride content of PYR14FSI was <1 ppm, Al electrodes were also pretty stable in this IL, and a similar cycling stability during float tests than for PYR 14TFSI could be obtained. © 2013 Elsevier B.V. All rights reserved.