High proton conductivity and low fuel crossover of polyvinylidene fluoride-hexafluoro propylene-silica sulfuric acid composite membranes for direct methanol fuel cells

Proton exchange membranes were fabricated by directly blending polyvinylidene fluoride-hexafluoro propylene with silica sulfuric acid for the application of direct methanol fuel cells. Morphological and structural characterizations of the prepared membranes were characterized by scanning electron microscopy and infrared spectroscopy, respectively. The performed thermal gravimetric analysis ensured high thermal stability of the prepared membranes. The ion transport and fuel permeation of the fabricated composite membranes were solely governed by the hydrophilic and hydrophobic regions of silica sulfuric acid and host polymer matrix, respectively. The fabricated composite membrane exhibited a maximum fuel cell power density of 43 mW/cm ² through the high ionic conductivity and low fuel permeability parameters and can be considered as a good contender for direct methanol fuel cells.