Research into the design of electrolytes of ionic liquids (ILs) for supercapacitor applications has grown in popularity in recent years. Unlike Li batteries where the composition of the electrolyte and the stability must meet several requirements (formation of SEI, electrochemical kinetics), the use of ionic liquids in supercapacitors opens interesting perspectives, in particular thanks to their high electrochemical stability. [1]. In this communication, it will be presented the results of an experimental study conducted using quartz crystal microbalance (eQCM) on nanoporous carbon based electrodes in contact with different electrolytes : neat IL and solvated IL as well as electrolyte mixture. EQCM turns out to be an effective analytic tool to bring new insights regarding the charge compensation mechanisms occurring while polarizing the carbon based electrode. In particular, it will be shown that charge compensation can involve different levels of desolvation of the counter-ions and that co-ions can also be used when the carbon electrode is polarized [2,3,4].

Références :
[1] P. Simon et Y. Gogotsi, Nature Materials, 7 (2008) 845-854.
[2] W.-Y. Tsai et al. JACS 8722−8728 (2014)
[3] J. Griffin et al., Nature Materials, 22 juin 2015 (doi: 10.1038 / nmat4318).
[4] Y.-C. Wu, P.-L. Taberna, P. Simon, Communications en électrochimie. 93, 119-122 (2018).