Universal scaling of charge transport in glass-forming ionic liquids

Charge transport and glassy dynamics of a variety of glass-forming ionic liquids (ILs) are investigated in a wide frequency and temperature range by means of broadband dielectric spectroscopy, differential scanning calorimetry and rheology. While the absolute values of dc conductivity and viscosity vary over more than 11 decades with temperature and upon systematic structural variation of the ILs, quantitative agreement is found between the characteristic frequency of charge transport and the structural alpha-relaxation. This is traced back to dynamic glass transition assisted hopping as the underlying mechanism of charge transport.