Preparation and properties of novel sulfonated poly(phthalazinone ether ketone) based PEM for PEM fuel cell application

Novel sulfonated poly(phthalazinone ether ketone) (SPPEK) was synthesized by direct polymerization via NC coupling reaction. The membrane based on SPPEK was simply obtained by casting from 5% solution of SPPEK in N,N-dimethylacetamide (DMAc) at 60 °C. The as-made membrane was characterized by ion-exchange capacity (IEC), thermal analysis, proton conductivity, single cell performance and electrochemical impedance spectra (EIS). The SPPEK membrane showed excellent characteristic as a proton exchange membrane (PEM) for PEMFC application, such as high ionic exchange content (IEC) of 2.04 mequiv g−1, high water uptake of 50.6% at 100 °C, the proton conductivity of 1.06 × 10−2 S cm−1 at 20 °C, as well as the superior anti-hydrolytic ability and mechanical strength. Moreover, the membrane exhibited higher thermal stability than Nafion 115. Cell evaluation experiment demonstrated a better performance of SPPEK than that of Nafion 115-cell. Finally, electrochemical impedance spectra (EIS) was conducted to measure the charge transfer resistance to compare the difference between SPEEK and Nafion 115.