Characterizations of PMMA-based polymer electrolyte membranes with Al 2 O 3

Poly(methyl methacrylate) (PMMA)-based polymer electrolyte membranes are prepared through the solution cast method, with PMMA:ethylene carbonate (EC):LiCF 3 SO 3 :Al 2 O 3 weight ratio of 55.13:18.34:24.5:2. The effect of Al 2 O 3 filler grain sizes of 50 nm and 10 μm on the polymer electrolytes was studied in this work. From the Cole-Cole plot obtained through electrochemical impedance spectroscopy, the highest ionic conductivity for 50-nm Al 2 O 3 in the PMMA-LiCF 3 SO 3 -EC-Al 2 O 3 sample was measured as 1.52 × 10 −4 S/cm at room temperature. The bonding formation among the host polymer and other additives in the polymer electrolytes has been studied using Fourier transform infrared spectroscopy. A strong occurrence of CH 3 stretching mode has proven that nano size Al 2 O 3 results in a much stronger bonding effect with the host polymer. The particle sizes were calculated by applying the Debye-Scherrer equation from the X-ray diffraction results. This work considers the effect of instrument broadening to further improve the accuracy of particle broadening for particle size calculation. The average particle size of nano size Al 2 O 3 in the PMMA sample is calculated as 2.9693 nm. Moreover, a higher amorphousity level obtained from nano size filler polymer electrolyte of 98.5% computed from differential scanning calorimetry thermograms had also explained the achievement of high ionic conductivity in this work.