New Local Composition Model for Correlating of the Molar Conductivity of Ionic Liquid–Solvent Systems over the Whole Concentration Range

Considering that traditional electrolyte models are limited to use in the solvent-rich region, the development of new models to describe the molar conductivity (Λm) over the whole concentration range of ionic liquid (IL)–solvent systems is a meaningful study. Based on the idea of local composition and the law of independent ion migration, a new model is proposed in this study and used to successfully correlate the relationship between Λm and composition over the whole concentration range for 18 IL–solvent systems with satisfactory fitting accuracy. Meanwhile, the electrical conductivity (κ) of the systems is estimated using the calculated Λm. Moreover, the strength of anion–cation, anion–solvent, and cation–solvent interactions in the systems is explored by the obtained energy parameters, and the effect of the solvent on the interactions is investigated. The proposed model provides a new method to accurately describe the conductivity property of IL–solvent systems over the whole concentration range.