Dielectric Properties Of Confined Ionic Liquids

Ionic liquids, as solvent free electrolytes, are promising materials improving the energy density of future storage devices. Two key requirements for such an application are a broad electrochemical window and a high ionic mobility of ionic liquids. A thorough measurement of the dielectric properties in a broad temperature and frequency regime allows analyzing the latter one in detail. Ionic mobility is influenced by intrinsic relaxations. These relaxations are influenced by correlation between the molecules. Confining the molecules allows to access this correlation length and to address the fundamental questions regarding supercooled liquids. We demonstrate this by confining the ionic liquid 1-butyl-3-methyl-imidazolium chloride in a metal-organic-framework, namely MFU-4. The preliminary results of an enhanced rotational motion compared to the bulk ionic liquid point towards a temperature, where the correlation length corresponds to the pore diameter of the confining host.