Lithium Ion Transport Across and Between Phase Boundaries in HeterogeneousPolymer Electrolytes, Based on PVdF

摘要

Initial investigations of polymer electrolytes based on PVdF-HFP and LiPF6dissolved in either EC/PC or EC/DMC mixtures have been carried out via high pressure complex impedance methods and 7Li NMR. All results indicate that the polymer matrix, while effectively immobilizing the liquid component, does not significantly affect the ion transport mechanism inherent to liquid electrolytes. In the first reported attempt to exploit 17O NMR to study lithium battery electrolytes, we have prepared 17O-enriched Li triflate and several electrolytes containing the isotopically enriched salt dissolved in DEC, DMC, and mixtures of DMC/EC. Line widths were measured as a function of electrolyte solvent and temperature, and suggest that EC inhibits the formation of ion pairs, when added to DMC.