Computer Simulation Study of the Solvation of Lithium Ions in Ternary Mixed Carbonate Electrolytes: Free Energetics, Dynamics, and Ion Transport
Journal
PCCP (Physical Chemistry Chemical Physics)
Date
2018.11.08
Abstract
A ternary mixture of EMC, DMC, and EC, is a common solvent used for Li ion batteries. The effect of EC on the solvation structure, free energetics and related dynamics of the ternary mixed carbonate electrolyte with LiPF6 is systematically investigated by MD simulations. A EC co-solvent tends to decrease the structural heterogeneity and solvent fluctuation in the solvation of Li ions. As the EC concentration increases, the solvation structural relaxation for Li ions accelerates in the subpicosecond regime, whereas the diffusional motion of ions slow down. The electrolyte viscosity and solvation structure changed by EC contribute to the ionic conductivity in an opposite manner, as a result, their ionic conductivity exhibits non-monotonic behavior acoording the EC concentration.