Multilayered sulphonated polysulfone/silica composite membranes for fuel cell applications

Polymer electrolyte membranes used in proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC) suffer from low dimensional stability. Hence multilayered membranes using sulfonated polysulfone (SPSu) and silica (SiO2) were fabricated to alter such properties. The introduction of an SiO2 layer between two layers of SPSu to form the multilayered composite membrane enhanced its dimensional stability, but slightly lowered its proton conductivity when compared to the conventional SPSu/SiO2 composite membrane. Additionally, higher water absorption, lower methanol permeability and higher flame retardancy were also observed in this newly fabricated multilayered membrane. The performance evaluation of the 2 wt% SiO2 loaded multilayered membrane in DMFC showed a maximum power density of 86.25 mW cm−2, which was higher than that obtained for Nafion 117 membrane (52.8 mW cm−2) in the same single cell test assembly. Hence, due to the enhanced dimensional stability, reduced methanol permeability and higher maximum power density, the SPSu/SiO2/SPSu multilayered membrane can be a viable and a promising candidate for use as an electrolyte membrane in DMFC applications, when compared to Nafion.

► Multilayered membranes were fabricated with SPSu. ► Aminated polysulfone and silica were used as the layers in order to prevent the crossover of methanol. ► The methanol permeability and selectivity ratio proved a strong influence on DMFC application. ► The suitability of the multilayered membranes was studied in the lab made set-ups of PEMFC and DMFC.