Effect of ZnO Nanoparticle Content on the Structural and Ionic Transport Parameters of Polyvinyl Alcohol Based Proton-Conducting Polymer Electrolyte Membranes

Proton conducting nanocomposite solid polymer electrolytes (NSPEs) based on polyvinyl alcohol/ammonium nitrate (PVA/NH4NO3) and different contents of zinc oxide nanoparticles (ZnO-NPs) have been prepared using the casting solution method. The XRD analysis revealed that the sample with 2 wt.% ZnO-NPs has a high amorphous content. The ionic conductivity analysis for the prepared membranes has been carried out over a wide range of frequencies at varying temperatures. Impedance analysis shows that sample with 2 wt.% ZnO-NPs has a smaller bulk resistance compared to that of undoped polymer electrolyte. A small amount of ZnO-NPs was found to enhance the proton-conduction significantly; the highest obtainable room-temperature ionic conductivity was 4.71 x 10(-4) S/cm. The effect of ZnO-NP content on the transport parameters of the prepared proton-conducting NSPEs was investigated using the Rice-Roth model; the results reveal that the increase in ionic conductivity is due to an increment in the number of proton ions and their mobility.

Automated summary

Proton conducting nanocomposite solid polymer electrolytes based on PVA/NH4NO3 and different contents of ZnO-NPs were prepared using the casting solution method. The sample with 2 wt.% ZnO-NPs showed high amorphous content and lower bulk resistance, leading to significantly enhanced proton conduction. The increase in ionic conductivity was attributed to the higher number and mobility of proton ions in the presence of ZnO-NPs.