Molecular Dynamics Simulations of Ionic Liquid Based Electrolytes for Na-Ion Batteries: Effects of Force Field

Abstract

Classical molecular dynamics simulations were performed for Na+ conducting electrolytes based on EMIM-TFSI ionic liquid and NaTFSI salt. Several parametrizations of force fields have been tested, including polarizable fields with dipole polarizabilities or Drude-type polarization. Trajectories up to 1 μs long have been used to estimate viscosities, diffusion coefficients, and conductivities of electrolytes with increasing amount of sodium salt. Results have been compared to available experimental data. In most cases the best agreement to measured values has been obtained in nonpolarizable simulations. Nevertheless, results have indicated the need for further development of polarizable parametrizations, preferably based on the Drude polarization model.