Structural, thermal, electrical and mechanical properties of nanosilica-composite polymer electrolytes

We synthesized a new kind of solid polymer electrolyte with polyethylene oxide (PEO) as a host, lithium triflate (LiCF3SO3) as a salt, mixtures of ethylene carbonate (EC) and dibuthyl phthalate (DBP) as a double plasticizer and nanosilica (SiO2) as a filler using the solution casting technique. Nanosilica was produced through mechanical milling with a size range of 60-80 nm as shown by transmission electron microscopy. X-ray diffraction patterns confirmed the complex formation of the PEO-LiCF3SO3-EC-DBP-SiO2 system. The optimum conductivity value at room temperature was 5.1 . 10(-3) S cm(-1) for 4 wt.% of SiO2. Differential scanning calorimetry results show that the glass transition temperature of the composite polymer electrolyte was found to increase when SiO2 was added. Addition of salt and plasticizers decreases the Young's modulus of the polymer electrolyte. However, the addition of 4 wt.% SiO2 increases the Young's modulus value from 5.1 . 10(-2) to 1.08 . 10(-1) MPa.