Synthesis and properties of densely sulfonated polyketones (sPKs) with rigid backbone structure for PEM fuel cell application

Densely sulfonated polyketones (sPK-m) based on poly(p-phenylene)s were successfully synthesized through Ni(0)-catalyzed cross coupling reaction for polymer electrolyte membrane fuel cell (PEMFC) application. sPK-m membranes exhibited proton conductivities comparable to or better than that of Nafion 212 in the hydrate state. sPK-12.5 and sPK-15 membranes showed outstanding PEM fuel cell performance at 80 °C under 100% RH. In particular, sPK-15 membranes exhibited very high current density (around 1300 mA/cm2 at 0.6 V). Among the synthesized polymers, sPK-12.5 showed reasonable dimensional change and morphological property. Furthermore, proton conductivity and cell performance comparable to those of Nafion 212 membrane were obtained.