Ionic Conductivity of PVA-based Gel Electrolyte Containing Diethyl Carbonate Plasticizer

High ionic conductivity polymer electrolyte has been developed as a replacement for liquid electrolytes, which are prone to leaking when employed in dye-sensitized solar cells. However, the high degree of crystallinity in the polymer electrolyte hinders further ionic conductivity improvement. In this study, a gel polymer electrolyte was synthesized by stirring polyvinyl alcohol (PVA) with potassium iodide (KI) salt in dimethyl sulfoxide (DMSO), ethylene carbonate (EC), and propylene carbonate (PC). Different concentrations of diethyl carbonate (DEC) which acts as a plasticizer were added to study the effect of plasticizers on electrolyte conductivity. Impedance spectroscopy (EIS) and X-ray diffraction (XRD) were utilized to investigate the ionic conductivity and structural of the gel electrolyte. Based on the EIS, the optimum ionic conductivity of similar to 11 x 10(-3) S cm(-1) was acquired with addition of 25 wt.% of DEC. This study demonstrates that adding 25% wt.% DEC increased the gel electrolyte's ionic conductivity, suggesting that the plasticizer contributes to better ion mobility in the gel electrolyte's polymer matrix. XRD analysis revealed a decrease in crystallinity in the presence of DEC. The highest conducting electrolyte can serve as electrolyte material in the dye-sensitized solar cells to further study on their performance. In conclusion, DEC may improve the ionic conductivity as well as the amorphous characteristics of gel polymer electrolyte.