Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 42: Materials for Energy Storage I (joint session KFM/CPP)

CPP 42.2: Vortrag

Mittwoch, 14. März 2018, 10:00–10:20, EMH 025

Dielectric properties of ionic liquid based electrolytes for future energy-storage systems — •Pit Sippel and Stephan Krohns — Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany

Electrolytes are essential for energy storage systems like electric double layer capacitor (EDLC). The so-called electrode polarization is the driving mechanism for energy storage in EDLCs. To enhance the properties of EDLCs, potential new electrolytes are investigated by various methods. Dielectric spectroscopy is a powerful tool analyzing the electric properties of liquids. This technique allows measuring the relaxation times of dynamic processes and ionic conductivity in a broad frequency and temperature range. Especially, the ionic conductivity is an essential figure of merit for any energy-storage application. This talk addresses the dielectric properties of ion conducting liquids with special emphasize put on ionic liquids (ILs). The revealed spectra are analyzed using equivalent circuits, which enable investigating the important electrode polarization effect. ILs offer outstanding properties (e.g., low volatility and high electrochemical stability) making them promising candidates for solvent-free electrolytes, which may improve energy-storage systems. However, the applicability of ILs is still hampered due to their rather low conductivity. We address the question if this conductivity can be optimized by mixing pure ILs taking into account the non-canonical super-Arrhenius temperature dependence [1]. [1] E. Thoms et al., Sci. Rep. 7, 7463 (2017).