Effect of Al2O3 Nanofiller on ion conductivity, transmittance, and glass transition temperature of PEI: LiTFSI: PC: EC polymer electrolytes

In the present study, ion conductivity, optical properties, and glass transition temperatures are characterized for polymer electrolytes composed of poly(ethyleneimine) (PEI), lithium bis(trifluoromethane) sulfonylimide (LiTFSI) salt, propylene carbonate (PC), and ethylene carbonate (EC). It was doped with nanoceramic particles in different ratio (0-5 wt.%) to see the effect of ceramic particles. The salt concentration was fixed as 1.04 mol. kg(-1). Although valuable improvement in ion conductivity could not be achieved due to nano-Al2O3 fillers, ion conductivity results are placed between 10(-2) and 10(-4) S/cm. Differential scanning calorimetry (DSC) measurements and optical measurements of all electrolytes were performed between -80 and 140 degrees C, in the wavelength range between 400 and 700 nm for sample with 80 mu m thickness, respectively. The results showed that transmittance of electrolytes decreased monotonically for increasing Al2O3 contents. In particular, its transmittance value at 550 nm where human sight is at its greatest sensitivity went from 100% without nanoparticles to 50% for 15 wt% of Al2O3.