Abstract:

A room temperature ionic liquid, 1-allyl-3-methylimidazolium tetrafluoroborate([AMIM]BF4) was prepared by a two-step synthesis. Then gel polymer electrolytes(GPE) prepared by incorporating the ionic liquid [AMIM]BF4 and poly(methyl methacrylate)(PMMA) were modified with aprotic solvents propylene carbonate(PC) and dimethyl carbonate(DMC) and SiO2 nano particles. The structure and properties of the GPE were studied by means of fourier transform infrared spectroscopy(FT-IR), A.C. impedance(AC), thermogravimetry(TG), and scanning electron microscope(SEM). The results showed that the introduction of aprotic solvents PC-DMC and nano-SiO2 particles increased the ionic conductivity of the GPE, which showed a highly ionic conductivity of up to 5.25×10-3 Ｓ/cm at room temperature. In addition, the conductive behavior of the GPE follows an Arrhenius equation. The gel polymer electrolytes shows high thermal stability and tends to decompose at temperature higher than 300 ℃.

Key words: gel polymer electrolyte, ion conductivity, ionic liquids, aprotic solvents, SiO2 nano particles