Anion exchange composite membranes composed of poly(phenylene oxide) containing quaternary ammonium and polyethylene support for alkaline anion exchange membrane fuel cell applications

Novel anion exchange composite membranes with controlled thicknesses have been developed by a simple pore-filling method using poly(phenylene oxide) containing a quaternary ammonium group as an anion conducting polymer electrolyte and a polyethylene porous substrate support for alkaline anion exchange membrane fuel cell applications. The thickness optimization could be done by controlling the viscosity of the polymer electrolyte solution. The resulting composite membrane prepared using 5 centipoise (cP) viscous polymer electrolyte solution composed of the co-solvent system such as dimethylacetamide (DMAc) and ethanol showed a uniformly thin structure of about 40 μm thickness. Among the composite membranes developed here, the membrane with the optimized thickness exhibited high tensile strength (45.6 MPa), and a low contact angle (13.19°) indicative of a hydrophilic surface, as well as high hydroxide conductivity (38.9 mS/cm) due to the combined effect of the reinforcement of the robust PE substrate and the sound impregnation of aminated poly(phenylene oxide). Membrane electrode assembly using A-PPO30E200 revealed excellent cell performance (peak power density:153 mW/cm2 at 0.43 V) than those of commercial FAA-3-50 Fumatech anion exchange membrane (peak power density:114 mW/cm2 at 0.43 V) under the operating condition of 60 °C and 100% RH.