Energy

# Modeling the Effects of Salt Concentration on Aqueous and Organic Electrolytes

## Abstract

Understanding the thermodynamic properties of electrolyte solutions is of vital importance for a myriad of physiological and technological applications. The activity coefficient γ± is associated with the deviation of an electrolyte solution from its ideal behavior and may be obtained by combining the Debye-Hu ̈ckel (DH) and Born (B) equations. However, the DH and B equations depend on the concentration and temperature-dependent static permittivity of the solution εr (c, T ) and size of the solvated ions ri, whose experimental data is often not available. In this work, we use a combination of molecular dynamics and density functional theory to predict εr (c, T ) and ri, which enables us to apply the DH and B equations to any technologically relevant electrolyte at any concentration and temperature of interest.

## Supplementary material

Supplementary Information
The Supporting Information contains: 1. Obtaining the Born Radius. 2. Molecular Dynamics Simulations. 3. Obtaining the Static Permittivity. 4. Conversion from Molality to Molarity. 5. Obtaining $R^\mathrm{B}$ via Density Functional Theory. 6. Accuracy of the Calculated Static Permittivities. 7. On the Effect of Using $\rho_\mathrm{solvent}$ when Converting from $m$ to $M$. 8. Supporting Figures 9. Supporting Tables