Finally, the salt content also has a profound impact on the temperature dependence of the self-diffusion coefficients. Figure in the SI depicts Arrhenius plots of the temperature dependence of the system-size independent selfdiffusion coefficients D 0 for all the species involved. Note that for the considered composition and temperature range, all species obey the Arrhenius relation very well. The respective activation energies E a , given in Table in the SI, show that increasing the salt content not only slows down the dynamics but also leads to a significant increase of the activation energy: from about 18 kJ mol -1 for low salt concentrations to values between 31 kJ mol -1 and 33 kJ mol -1 for the 1:1 mixture.