Preparation and Properties of Composite Proton Exchange Membranes Based on SPES/SiO2 Hybrid Nanofiber

Sulfonated poly (ether sulfone) (SPES) /Silica (SiO2) nanofibers were prepared by solution blowing process, and impregnated to Nafion matrix to prepare SPES/SiO2/Nafion composite proton exchange membranes (PEMs). The characteristics of the composite membrane, such as morphology, thermal stability, proton conductivity and performance of membrane as PEMs, were investigated. The results showed that the introduction of solution-blown nanofibers to composite membranes significantly improved properties of Nafion. The TG results showed all the composite membranes had better thermal stability than pure Nafion. Swelling ratios of all the composite membranes were lower than that of pure Nafion, and those of SPES/SiO2/Nafion-5, SPES/SiO2/Nafion-15 and SPES/SiO2/Nafion-25 were 14.9%,15.84% and 17.2% at 80 degrees C, respectively. However, the swelling ratios of composite membranes increased with the increase of SiO2 content in nanofiber. Proton conductivity of the composite membranes increased first and then decreased with the increase of SiO2 content, and the membrane containing 15% SiO2 could get 0.154 S/cm at 80 degrees C and 100% humidity. Besides, the methanol resistance was also greatly improved, methanol permeability of the composite membrane containing 25% SiO2 decreased by 55.3% compared to that of Nafion. Therefore, the composite membrane containing hybrid SPES/SiO2 nanofibers can be considered as a promising PEM for fuel cell applications.