The role of MgBr2 to enhance the ionic conductivity of PVA/PEDOT:PSS polymer composite

A solid polymer electrolyte system based on poly(vinyl alcohol) (PVA) and poly(3,4-Etylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) complexed with magnesium bromide (MgBr2) salt was prepared using solution cast technique. The ionic conductivity is observed to increase with increasing MgBr2 concentration. The maximum conductivity was found to be 9.89 × 10−6 S/cm for optimum polymer composite film (30 wt.% MgBr2) at room temperature. The increase in the conductivity is attributed to the increase in the number of ions as the salt concentration is increased. This has been proven by dielectric studies. The increase in conductivity is also attributable to the increase in the fraction of amorphous region in the electrolyte films as confirmed by their structural, thermal, electrical and optical properties.