Structure and polarization near the Li ion in ethylene and propylene carbonates.

Research on fundamental interactions in Li-ion batteries is accelerating due to the importance of developing batteries with enhanced energy and power densities while maintaining safety. Improving electrode materials and controlling the formation of the solid electrolyte interphase during the first battery charge have been the main focus areas for research. Ion-solvent interactions in the electrolyte are also of great importance in tuning solvation and transport properties, however. Here we present ab initio density functional theory simulations of a Li ion in ethylene and propylene carbonates. The aim is to obtain a detailed analysis of local solvation structure and solvent polarization near the ion and in the bulk. The results indicate the significance of molecular polarization for developing accurate solvation models. The simulations illustrate the substantial differences between ion solvation in water and in organic materials.