Fabrication of highly selective SPVDF-co-HFP/APTES-SiO2/Nafion nanocomposite membranes for PEM fuel cells

Polyelectrolyte membrane (PEM) with improved proton conductivity and low methanol crossover are highly desirable for direct methanol fuel cells (DMFCs). Herein, the prime goal is to fabricate a ternary hybrid nanocomposite PEM by incorporating low-cost silane functionalized silica nanoparticles (AMPS) nanoparticles into the mixture of Nafion and PVDF-co-HFP, followed by sulfonation with chlorosulfonic acid which has not been reported by any earlier studies. Various physicochemical characterizations including FTIR, TGA, XRD, FESEM-EDS have been performed for the confirmation of formed sulfonated PVDF-co-HFP-AMPS-Nafion (SPAN) membranes. The initial studies including water/methanol uptake, swelling ratios, contact angle and improved ion exchange capacity (0.65 meq. g⁻¹) confirms the hydrophilic and ion exchange properties of the SPAN membranes. The combination of highly hydrophobic partially fluorinated polymer along with hydrophilic AMPS and sulfonic acid moieties have resulted in significant improvement in proton conductivities (1.0 × 10^–1 S.cm⁻¹) and optimum methanol permeability values (8.79 × 10^–7 cm²s⁻¹) thereby exhibiting a better membrane selectivity value of 1.18 × 10⁵ S.scm⁻³. Therefore, these unique SPAN membranes have the potentiality to be employed in methanol fuel cells.