Composite Nafion/polyphenylene oxide (PPO) membranes with phosphomolybdic acid (PMA) for direct methanol fuel cells

The preparation and characterization of new polymer composite membranes containing polyphenylene oxide (PPO) thin films with phosphomolybdic acid (PMA) are presented. PPO thin films with PMA (PPO-PMA films) have been prepared by using the solvent mixture. In this study, methanol was used as a solvent dissolving PMA and chloroform was used as a solvent dissolving PPO. PPO-PMA solutions were cast onto a glass plate. The composite membranes were prepared by casting Nafion mixture on porous PPO-PMA films. The composite membranes were characterized by measuring their ion conductivity and methanol permeability. The morphology and structure of these PPO-PMA films were observed with scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and wave dispersive spectrometer (WDS). The composite membranes are tested as electrolytes in a direct methanol fuel cells (DMFCs). The performance tests have shown that they have a good perspective in this DMFCs. The methanol cross-over in the DMFC can be reduced by composite membranes containing PPO-PMA barrier films.