Solvation of the Fluorine Containing Anions and Their Lithium Salts in\n Propylene Carbonate and Dimethoxyethane

Electrolyte solutions based on the propylene carbonate (PC)-dimethoxyethane\n(DME) mixtures are of significant importance and urgency due to emergence of\nlithium-ion batteries. Solvation and coordination of the lithium cation in\nthese systems have been recently attended in detail. However, analogous\ninformation concerning anions (tetrafluoroborate, hexafluorophosphate) is still\nmissed. This work reports PM7-MD simulations (electronic-structure level of\ndescription) to include finite-temperature effects on the anion solvation\nregularities in the PC-DME mixture. The reported result evidences that the\nanions appear weakly solvated. This observation is linked to the absence of\nsuitable coordination sites in the solvent molecules. In the concentrated\nelectrolyte solutions, both BF4 and PF6 prefer to exist as neutral ion pairs\n(LiBF4, LiPF6).\n