Preparation of new polymer electrolytes based on poly(acrylonitrile-co-vinylimidazoline) matrix and improvement of polarization behavior of lithium electrode in the electrolyte by using cascade nitrile compound

New polymer electrolytes based on poly(acrylonitrile-co-vinylimidazoline), P(AN-VI) were prepared and their chemical and physical properties were characterized by conductance, DSC, and solid state 7Li- and 13C NMR measurements. Conductivity for the P(AN-VI)-based electrolytes was about 10−4 S cm−1 at 30 °C and 10−3 S cm−1 at 60 °C. Addition of the cascade nitrile compound, ED4CN {–[–CH2N(CH2CH2CN)2]2} which acts as a plasticizer for polyacrylonitrile-based electrolytes, to P(AN-VI)-based electrolytes reduced their conductivities. Polarization behavior of a lithium electrode in the P(AN-VI)-based electrolytes was improved by the addition of ED4CN. Exchange current density of the lithium electrode in the P(AN-VI)-based electrolyte with ED4CN was one order of magnitude higher than that in the ED4CN-free P(AN-VI) electrolyte. Addition of ED4CN to the P(AN-VI)-based electrolyte changed the environment of the lithium ions in the electrolyte. Dominant coordination of the ED4CN molecules to the lithium ions was confirmed by 7Li NMR measurements and increased the effective concentration of the lithium ions in the electrolytes.