Charge transfer and electrical double layer of an amphiphilic protic ionic liquid in bulk and when confined in nanochannels
Journal article, 2022

We report the behavior of the protic and surface active ionic liquid octylimidazolium bis(trifluoromethylsulfonyl)imide, [HC(8)Im][TFSI], in bulk and inside silica nanochannels, at the interface with the conductive substrate indium tin oxide (ITO) upon applied potential. The two distinct cases of the ionic liquid being in contact with a bare ITO substrate and an ITO substrate covered with a thin film of mesoporous silica containing vertically-aligned channel-like pores have been investigated. These correspond to the behavior of the bulk ionic liquid and the ionic liquid confined within nanochannels (approximately 3.5 nm wide and 65 nm long). Broadband dielectric spectroscopy (BDS) and electrochemical impedance spectroscopy (EIS) have been used as the experimental methods, while modelling with equivalent circuits has been applied to evaluate the experimental results. Thus, this study does not only show a functional ionic liquid/silica hybrid material, but also presents an in-depth electrochemical characterization revealing an enhanced specific capacitance at the confined-IL/ITO interface (similar to 16 mu F cm(-2)) as compared to the case of bulk IL/ITO (similar to 6 mu F cm(-2)). This suggests that local structure and ion ordering inside the nanochannels of silica are different from that of the bulk ionic liquid, favoring denser ionic packing and a higher specific capacitance at the metal interface.

Author

Szilvia Vavra

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Elisabet Ahlberg

University of Gothenburg

Anna Martinelli

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Physical Chemistry Chemical Physics

1463-9076 (ISSN) 1463-9084 (eISSN)

Vol. 24 39 24469-24479

Subject Categories

Inorganic Chemistry

Materials Chemistry

Other Materials Engineering

Areas of Advance

Materials Science

DOI

10.1039/d2cp01634f

PubMed

36193581

More information

Latest update

10/25/2023