Ion pairing in electrolyte solutions from molecular simulations

The structure and phase behavior of ion pairing in electrolyte solutions will be studied by molecular dynamics simulations from various angles.

Ion pairing, the association of oppositely charged ionic species has tremendous effect on the structure and physiochemical properties for electrolytes and a wide range of chemical and biological materials.

The ion-pair formation in electrolytes occurs when the coulombic forces between ions of opposite charge overcome the thermal energy.

The ion-pair formation is favored by the lower dielectric constant of the solvent, by the higher concentration of the ions, by the higher ion charge, and by the smaller ion radii. The association of two oppositely charged ions occurs when the distance between the ions becomes smaller than the Bjerrum critical distance.

However, experimental observations of ion pairing in the electrolytes are challenging due to difficulties in differentiating ion species.

In this project, the ion-pair formation will be analyzed by molecular dynamics simulations which is a method based on inter-molecular interactions to study the micro-structure, kinetics and thermodynamic properties.

This work will try to understand the molecular mechanisms of ion pairing with focus on single salt in pure water, a few cases of mixed salts in pure water or some typical mixed-solvents, to study the behavior and structure of the ion pairs, as well as to investigate the impact of ion pairs on properties of electrolyte solutions.

Main supervisor:

Associate Professor Xiaodong Liang


Co- supervisor:

Professor Georgios M. Kontogeorgis


Xiaodong Liang
Associate Professor
DTU Chemical Engineering
+45 45 25 28 77


Georgios Kontogeorgis
DTU Chemical Engineering
+45 45 25 28 59