Chemically Durable Poly(phenylene- co-arylene ether) Multiblock Copolymer-Based Anion Exchange Membranes with Different Hydrophobic Moieties for Application in Fuel Cells

Quaternized multiblock poly(phenylene-co-arylene ether)s (QPPs) are synthesized from a pre-aminated monomer and a series of chlorine-terminated oligo(arylene-ethers) via a nickel coupling reaction. Their properties are investigated as anion exchange membranes with the goal of obtaining membranes with enhanced performance and durability for alkaline membrane fuel cell applications. Three different oligo(arylene ethers) were synthesized and introduced in the hydrophobic block of the polymer backbone to study its effect on the membrane properties. The chloride ion conductivity of the QPP membranes was significantly less dependent on the humidity compared to that of the commercial Fumatech membrane due to the well-defined hydrophilic-hydrophobic phase separation, as confirmed by TEM. An accelerated alkaline stability test indicated that the QPPs were more stable than the commercial Fumatech membrane up to 1700 h. The QPP-6F membrane shows an alkaline membrane fuel cell single-cell performance with a maximum power density of 534 mW cm-2 at 70 °C.