Development of Composite Membranes of Sulfonated Poly(ether ether ketone) and Gadolinium-doped Ceria Nanoparticles for Polymer Electrolyte Membrane Fuel Cells

We introduce gadolinium (Gd)-doped cerium oxide (GDC) nanoparticles with hydrocarbon-based proton exchange membrane of sulfonated (ether ether ketone) (SPEEK) for realizing enhanced physical and chemical membrane stabilities. The oxygen vacancy of GDC increases with doping of Gd into ceria, enhancing the chemical stability from the radical degradation. The SPEEK/GDC composite membrane exhibits an increased proton conductivity at low relative humidity conditions due to its higher affinity with water molecules. Moreover, the GDC nanoparticles in the SPEEK matrix enhance not only the mechanical stability with preventing membrane swelling but also the radical resistive chemical stability of the composite membrane.