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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 42: Charged Soft Matter, Ionic Liquids and Polyions I
CPP 42.8: Vortrag
Mittwoch, 22. März 2017, 17:15–17:30, ZEU 114
Dielectric study on mixtures of ionic liquids — •Pit Sippel1, Erik Thoms1, Daniel Reuter1, Alois Loidl1,2, and Stephan Krohns1,2 — 1Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany — 2Institute for Materials Resource Management, University of Augsburg, 86152 Augsburg, Germany
Ionic liquids are salts that are liquid below 100 ∘C and offer outstanding properties (e.g., low volatility and high electrochemical stability). These make them promising candidates for solvent-free electrolytes to improve energy storage systems [1]. However, most ionic liquids exhibit low conductivity, hampering their applicability in supercapacitors and battery systems. We demonstrate the tuning of the conductivity via mixing various ionic liquids. An increased conductivity has been reported for particular mixing series. Nonetheless, these are exceptions and most mixing series behave close to linear mixing-laws. To gain more insight into the molecular dynamics we performed detailed investigations by dielectric spectroscopy and differential scanning calorimetry on two mixing series of ionic liquids. The analysis of the glass temperatures and the thorough evaluations of the measured dielectric spectra reveal that the dynamics in these mixtures are well defined by the fractions of their parent compounds. Moreover the room-temperature conductivity in these mixtures is still directly related to their glass properties, as in pure ionic liquids [2].
D. R. MacFarlane, et al., Energy Environ. Sci. 7, 232 (2014).
P. Sippel et al., Sci. Rep. 5, 13922 (2015).