Molecular dynamics simulations of fluoroethylene carbonate and vinylene carbonate as electrolyte additives for Li-ion batteries

Abstract

ABSTRACT Contemporary electrolyte additives have captivated the attention of researchers since additives were reported to play a very crucial role in supporting the formation of an effective solid electrolyte interphase (SEI) in the case of silicon if used as an anode. The choice of a good solvent with additives demonstrates a significant impact on the solvation and diffusivity of lithium ions. Fluoroethylene carbonate (FEC) and Vinylene carbonate (VC) were extensively used additives for increasing the lifespan of Li-ion batteries (LIBs). In the current study, structural, dynamical, and transport properties of six different systems were investigated by applying classical molecular dynamics (MD) simulations. The properties obtained from the simulations suggested system E consisting of DMC, 1M LiPF, and 10% FEC, to be the best medium for the electrolytes for LIBs, since the diffusion coefficient of Li ions and ionic conductivity of LiPF were estimated to be of high values for the system E. However, before the evaluation of the transport properties, the structural properties in terms of radial distribution functions and spatial distribution functions were evaluated for DMC molecules with reference to DMC, Li, and PF ions. The structure data were also found to be in fair agreement with experimental and previous simulation results reported so far. Based on the finding of this study, it was suggested that DMC as a solvent with a 10% FEC additive could be considered a good medium for electrolytes for the improved performance of LIBs compared to VC as an additive to DMC.