Properties of gel electrolytes based on PVdF/HFP containing anion receptors

This work concerns systems utilizing gel electrolytes based on PVdF/HFP, containing a supramolecular compound additive. Supramolecular compounds are one of the many types of additives, and among them - anion receptors. Solutions of 1 M LiClO4 or 1 M LiBF4 in solvent: PC, PC/EC mixture (1:1), PC/DEC mixture (1:1) or EC/DEC mixture (1:1), were the liquid electrolyte encapsulated in a polymer membrane. N-[2-[Bis[2-N′-(3-pyridyl)ureido]ethyl]-amino]ethyl]-N′-(3-pyridyl)urea was applied as the supramolecular compound - anion receptor. Content of the receptor varied from 5 to 20 mmol in 10 cm3 of 1 M lithium salt solutions. Changes in ionic conductivity and the stability of gel electrolytes - lithium electrode interface, were analyzed on the basis of impedance spectroscopy technique in Swagelok geometry. Lithium transference number was calculated for some of the studied gels using the polarization method. Finally, thermal stability of the systems studied was determined by means of DSC technique.