Effect of dibutyl phthalate as plasticizer on high-molecular weight poly(vinyl chloride)–lithium tetraborate-based solid polymer electrolytes

Abstract

A series of different composition of polymer electrolytes-based on poly(vinyl chloride) (PVC) as host polymer, lithium tetraborate (Li2B4O7) as dopant salt, and dibutyl phthalate (DBP) as plasticizer were prepared by solution casting method. The interaction between the PVC, Li2B4O7, and DBP were studied by Fourier transform infrared. The shifting, broadening, and splitting of transmission peaks were the evidences of complexation. The highest ionic conductivity polymer electrolyte of 2.83 × 10−6 S/cm was achieved at ambient temperature upon addition of 30 wt.% of DBP. In addition, the temperature-dependent conductivity, frequency-dependent conductivity, dielectric permittivity, and modulus studies were performed. The temperature-dependent conductivity of the polymer electrolytes was found to obey the Arrhenius behavior. The thermal stability of polymer electrolytes was verified by thermogravimetric analysis. The lower in glass transition temperature was proven in differential scanning calorimetry, whereas the higher amorphous region within the polymer matrix was demonstrated in X-ray diffraction.