Strengthening of perfluorosulfonic acid ionomer with sulfonated hydrocarbon polyelectrolyte for application in medium-temperature fuel cell

The mechanical properties and conductivity, as well as the water sorption and transport properties, of a new series of blends of perfluorosulfonated acid ionomer (PFSA, Aquivion®) and disulfonated poly(aryl ether ketone) (DS-PAEK) with compositions ranging between 10 and 90 wt% were studied. For 10-20 wt% sulfonated hydrocarbon polyelectrolyte blends, the main mechanical relaxation temperature of side chains of Aquivion® increased 10-20 °C as compared to pure Aquivion®. This shift demonstrates the presence of interactions between Aquivion® and DS-PAEK while the ion exchange capacity, the capacity to absorb water, and the proton conductivity of blends remained very close to those of pure Aquivion®. In addition, these new materials show improved robustness and better performance in fuel cell operation at 105 °C as compared to Aquivion®. These results indicate that PFSA materials can be strengthened by adding a sulfonated hydrocarbon ionomer.