Preparation and characterization studies of PMMA-PEO-blend solid polymer electrolytes with SiO2 filler and plasticizer for lithium ion battery

Solid polymer electrolyte systems comprising of polyethylene oxide (PEO) and polymethyl methacrylate (PMMA) as blended polymer host, lithium trifluoromethanesulfonate (LiCF3SO3) as dopant salt, ethylene carbonate (EC) as plasticizer, and silicon dioxide (SiO2) as inorganic filler were prepared by solution casting method. PMMA-PEO-EC-LiCF3SO3-SiO2-blend solid polymer electrolytes were prepared to study the blending effect of PMMA into PEO solid polymer electrolytes. All the resulted solid polymer electrolytes were characterized using electrochemical impedance spectroscopy (EIS), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) methods. In the present study, the XRD, FTIR, SEM, and DSC results show clear evidence of the miscibility of PMMA and PEO. The incorporation of PMMA into the PMMA-PEO-blend solid polymer electrolytes shows significant improvement on ionic conductivity when small amount of PMMA is used. The highest ionic conductivity of 2.6301x10(-4)S/cm is achieved for 5wt% PMMA and 95wt% PEO-blend solid polymer electrolytes at room temperature. The ionic conductivity values are found to be decreased when a higher wt% of PMMA is added. Upon incorporation of 20wt% of PMMA, the ionic conductivity values are found in range of 10(-6) to 10(-7)S/cm. This finding is comparable with the reported results for gel-type polymer electrolytes. Hence, the amount of PMMA used in the PMMA-PEO-blend systems is crucial in the preparation of PMMA-PEO-blend solid polymer electrolyte.