Nonaqueous gel electrolytes doped with phosphoric acid esters

Highly conducting anhydrous gels doped with phosphoric acid esters have been obtained by entrapping ester solutions in polar aprotic solvents into the poly(vinylidene fluoride) or poly(methyl methacrylate) matrices. The dependence of the physical–chemical properties of these materials on the type and concentration of proton donor, as well as solvent used, are described. It is found that use of propylene carbonate-N,N-dimethyl formamide solvent mixture allows to obtain transparent gels in a wide (5–40 mass%) ester concentration range. Conductivities exceeding 5×10−4 S cm−1 (PVdF-based systems) and 1×10−3 S cm−1 (PMMA-based gels) are reported. The mechanism of proton conduction is discussed on the basis of impedance spectroscopy and PFG NMR experiments.