Florian JÖRG1, Christian SCHRÖDER1, Marcus WIEDER1
1University of Vienna, Vienna, Austria
Protic ionic liquids are promising candidates particularly, but not exclusively, for future battery generations, due to their non-flammability and avoidance of critical raw material. The key property of these substances is their reversible proton transfer, thus being able to form hydrogen-bonded networks. Consequentially, the conductivity increases. All these properties were investigated based on the model compound 1-methylimidazolium acetate using computer simulations. A newly developed polarizable force field was used to investigate several mixtures of the neutral and charged species. The equilibrium position was determined not only by single value properties like density, diffusion coefficients or conductivity, but also the complete frequency dependent dielectric spectrum. All data were compared to experimental values.
In order to tackle the drawback of conventional molecular dynamics simulations, which do not allow for bond breaking or formation, a new open-source program, called protex, was developed, which enables proton exchange between molecules in computer simulations. With the help of protex, various transfer reactions between molecules can be defined and specified by means of different parameters. Deeper insight into transport mechanisms and aid in the understanding of experimental data is now possible. Protex was applied to 1-methylimidazolium acetate and transport properties were calculated and compared to experimental data as well as conventional molecular dynamics simulations.