Direct Measurement of the Differential Capacitance of Solvent-Free and Dilute Ionic Liquids

Monchai Jitvisate, James R.T. Seddon* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

19 Citations (Scopus)
71 Downloads (Pure)

Abstract

Differential capacitance is a key quantity in the understanding of electrical double-layer charging of electrolytes. However, experimental observations of ionic liquid systems are controversial, inconsistent, and often unable of confirming or refuting existing theories as well as highlighting discrepancies between the measurement techniques. We study the differential capacitance in both pure and dilute ionic liquids at room temperature. Using chronoamperometry to measure the differential capacitance of the liquids at a polycrystalline platinum electrode, we find good agreement between the measured capacitance curves and the extended mean-field model of Goodwin-Kornyshev [Goodwin, Z. A.; et al. Electrochim. Acta. 2017, 225, 190-197]. A crossover is found from the pure to the dilute regime, as shown by a transition from a camel-shape capacitance curve to a U-like one, together with a nonmonotonic dependence of capacitance with electrolyte concentration.

Original languageEnglish
Pages (from-to)126-131
Number of pages6
JournalJournal of physical chemistry letters
Volume9
Issue number1
DOIs
Publication statusPublished - 4 Jan 2018

Keywords

  • UT-Hybrid-D

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