Description of ions properties using molecular orbital energy levels: Trends in interaction with model electrodes and solvents

Abstract

The study reveals correlations between the parameters of ions and their HOMO and LUMO orbital energy level values. In particular, it demonstrates a clear correlation for the ion adsorption parameters on model electrodes: the aluminum oxide (0001) surface, graphene and Au (111) surface. Correlations are also observed for the parameters of ion binding to water and dimethyl carbonate molecules, which are often used as solvents. In addition, the dipole moment, polarizability and solvation energy of ions are well correlated with the values of the molecular orbital energies, and for anions a dependence on the oxidation potential is observed. The experimental ion parameters reported in the literature also show correlations with the energy levels of the ion orbitals. The obtained descriptors make it possible to select ions with desired values for a specific problem. As an illustrative example, in this work we consider the problem of displacement of water molecules from the inner electric double layer by ions, which is one of the factors increasing the potential window in electrolytes of aqueous batteries. This approach can be applied in the rapidly developing field of aqueous electrolytes for battery or supercapacitor design, catalysis control through surface composition variations, as well as in studies of heavy metal ion binding to sorption materials.