Rheological characterizations of ionic liquid-based gel polymer electrolytes and fumed silica-based composite polymer electrolytes

Abstract

In this work, two different polymeric systems were investigated. Ionic liquid-based gel polymer electrolytes (IL-GPEs) are designated as the first system and composite polymer electrolytes (CPEs) with addition of nano-sized fumed silica (SiO2) are assigned as the second system. From amplitude sweep and oscillatory shear sweep tests, it was found out that the values of storage modulus (G′) are much higher than loss modulus (G″), indicating the elastic behavior of these samples. No behavioral transition of samples was observed in the tests. Linear visco-elastic range (LVE) of samples becomes wider with increasing content of ionic liquid and SiO2. Long-term structural stability was enhanced upon addition of ionic liquid. In the frequency sweep test, the absence of G″ further confirmed the solid properties of samples. The inclusion of SiO2 did not show any improvement in the frequency sweep test. The zero-shear viscosities were reduced upon inclusion of ionic liquid and SiO2. In the viscosity curve, the decrement of viscosity was shown as increase in shear rate due to the structural changes.