Polarizable Molecular Dynamics and Experiments of 1,2-Dimethoxyethane Electrolytes with Lithium and Sodium Salts: Structure and Transport Properties

The structure and transport properties of electrolyte solutions of 1,2-dimethoxyethane (DME) having salts of Li+ with bis(trifluoromethanesulfonyl)imide ([TFSI]−) or Na+ with [TFSI]− are investigated with polarizable molecular dynamics and experiments. Polarizable force fields for Li+ and Na+ with DME and [TFSI]− were developed based on quantum chemistry calculations, ab initio molecular dynamics simulations, and thermodynamic liquid-state properties. Simulation results for density, viscosity, self-diffusion coefficient, and conductivity of the electrolytes all agree well with the trends and magnitudes of available experimental data for a wide range of salt concentrations. As the concentration of salt increases, the electrolytes become more viscous and molecular species become less mobile. Ionic conductivity does not change monotonically with salt concentration and exhibits a maximum between 0.5 and 1.0 M for both Li[TFSI] and Na[TFSI] electrolytes. Comparatively, both cations are solvated by 5–6 DME or [...