Lithium-Ion Model Behavior in an Ethylene Carbonate Electrolyte Using Molecular Dynamics

The performance of lithium-ion batteries is strongly dependent on the nature of the electrolyte, and a better understanding of the role of the electrolyte in ion transport and the formation of the solid–electrolyte interface is critical for the performance improvement of such batteries. New cathode and anode materials demand new and/or improved electrolytes that are less sensitive to operating conditions and provide higher conductivity and mobility of ions between electrodes. A clear understanding of the solvation of electrolytes in solvents is essential for improving the performance and cycle life of Li-ion batteries. In this work, the behavior of lithium hexafluorophosphate (LiPF6) in ethylene carbonate was characterized using classical molecular dynamics simulations and ab initio density functional theory (DFT) calculations. The solvation structures of both Li+ and PF6– in the electrolyte were analyzed in detail, and the intermolecular and intramolecular potentials were found to produce all of the essential features of the electrolyte as observed from ab initio DFT calculations. The thermodynamics and transport properties obtained using molecular dynamics simulations were also found to be in good agreement with experimental values.