Dielectric Properties of Ethylene Carbonate and Propylene Carbonate Using Molecular Dynamics Simulations

Ethylene carbonate (EC) and propylene carbonate (PC) are two widely used solvents in Li-ion batteries and supercapacitors. Ion diffusion in these solvents depends strongly on accurate predictions of solvent dielectric properties. We used all-atom molecular dynamics simulations of these pure solvents to calculate dielectric constants and dielectric relaxation times at various temperatures. The dielectric constant measures polarization of a material whereas dielectric relaxation measures the lag of the polarization in a dielectric medium in responding to a change in an applied field. Predicted values are compared with the available experimental results to validate the force field parameters (OPLS-AA) for these solvents. Current results for dielectric constant and dielectric relaxation time indicate that OPLS-AA force field produces reasonable agreement with experiment for both EC and PC.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U. S. Department of Energys National Nuclear Security Administration under contract DE-AC04-94AL85000