Morphological and Electrochemical Properties of Zirconium Phosphate Functionalised PAN, PVA and PVP as Potential Fillers for Fuel Cell Membranes

Abstract

Recent interests in hybrid polymers for fuel cell applications have given rise to the exploration, modification, and application of various polymer ionomers. Polymer membranes doped with suitable fillers have improved fuel cell performance compared to the pristine polymers. In this study, three ionomers, PAN, PVP, and PVA were synthesised idividually and then functionalised with zirconium phosphate nanoparticles as membrane nanofillers. The nanofibers were synthesised using the sol-gel polymerisation method from their respective precursors dissolved in either water or DMF solution. This was followed by their subsequent fabrication through the incorporation of the zirconium phosphate nanoparticles, which were synthesised from their precursor salt using the precipitation method. Techniques such as SEM, FTIR, TGA, and XRD were employed to characterise the physiochemical properties of the synthesised polymers. In addition, the electrochemical properties of the synthesised polymers were evaluated using CV and EIS. The obtained results showed that conductive nanofibers were successfully synthesized. As the scan rates increased under cyclic voltammetry, the reduction peak for PVP voltammograms disappeared, and the PAN exhibited an irreversible redox system. It is also noticeable that when scan speeds increase, the oxidation peaks for PAN voltammograms shift to higher potentials. On the other hand, the TGA results indicated that these nanoparticles had excellent thermal stabilities, making them suitable for use in fuel cell membranes under tough conditions. Based on these findings, PAN, PVA, and PVP polymer materials can be used as filler (dopant) materials for fuel cell membranes.