Anomalous Capacitance Maximum of the Glassy Carbon-Ionic Liquid Interface through Dilution with Organic Solvents


Bozym D. J., URALCAN KILAVUZ B., Limmer D. T., Pope M. A., Szamreta N. J., Debenedetti P. G., ...Daha Fazla

Journal of Physical Chemistry Letters, cilt.6, sa.13, ss.2644-2648, 2015 (SCI-Expanded, Scopus) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 6 Sayı: 13
  • Basım Tarihi: 2015
  • Doi Numarası: 10.1021/acs.jpclett.5b00899
  • Dergi Adı: Journal of Physical Chemistry Letters
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.2644-2648
  • Anahtar Kelimeler: acetonitrile, capacitance, electrochemical impedance spectroscopy, glassy carbon, Ising model, room temperature ionic liquid
  • Boğaziçi Üniversitesi Adresli: Evet

Özet

We use electrochemical impedance spectroscopy to measure the effect of diluting a hydrophobic room temperature ionic liquid with miscible organic solvents on the differential capacitance of the glassy carbon-electrolyte interface. We show that the minimum differential capacitance increases with dilution and reaches a maximum value at ionic liquid contents near 5-10 mol% (i.e., μ1 M). We provide evidence that mixtures with 1,2-dichloroethane, a low-dielectric constant solvent, yield the largest gains in capacitance near the open circuit potential when compared against two traditional solvents, acetonitrile and propylene carbonate. To provide a fundamental basis for these observations, we use a coarse-grained model to relate structural variations at the double layer to the occurrence of the maximum. Our results reveal the potential for the enhancement of double-layer capacitance through dilution.