(555c) Ionic Conductivity of Imidazolium-Based Ionic Liquids: Nernst-Einstein and Einstein Formalism

In recent years, imidazolium-based ionic liquids (ILs) have emerged as a promising class of electrolytes for various electrochemical applications, such as energy storage devices, fuel cells, and electrochemical sensors. Understanding the ionic conductivity of these liquids is crucial for optimizing their performance in these applications. Molecular dynamics simulations provide a powerful tool for studying the transport properties of ILs at the molecular level. Through molecular simulation, this study aims to gain a deeper understanding of the behavior exhibited by ILs and quantify their ionic conductivity. Two different approaches, namely the Nernst-Einstein and Einstein formalisms, are employed to calculate the ionic conductivity of imidazolium-based ILs at three temperatures 313K, 333K, and 353K. We calculated the ionic conductivity of 1-ethyl-3-methylimidazolium cation combined with several anions, including tetrafluoroborate, dicyanamide, thiocyanate, bis(trifluoromethanesulfonate)imide, and trifluoromethanesulfonate. We compared our calculated conductivity with experimentally observed values. We found that the conductivity values of ILs containing tetrafluoroborate, trifluoromethanesulfonate, and bis(trifluoromethanesulfonate)imide anions were consistent with experimental values. However, the conductivity values of ILs containing thiocyanate anions were twice their experimental values. We will discuss challenges in calculating Einstein conductivity and provide guidance on when the ionic conductivities computed using the Nernst-Einstein formalism can serve as a surrogate for screening ILs for various electrochemical applications.