Alkali-stable partially fluorinated poly(arylene ether) anion exchange membranes with a claw-type head for fuel cells

To enhance the conductivity and alkaline stability of anion exchange membranes (AEMs), partially fluorinated poly(arylene ether) AEMs with functionalized claw-type side chains are prepared. It is found that the integration of a claw-type head into the side chain and a fluorinated moiety into the backbone is favorable for forming a well-defined hydrophilic/hydrophobic phase-separated structure, as confirmed by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). A highest hydroxide conductivity of 98.19 mS cm−1 is achieved for FPAE-3B-3.0-PD with an ion exchange capacity (IEC) of 1.16 meq. g−1. Besides, the as-prepared AEMs exhibit good dimensional stability, robust mechanical properties and high thermal stability. The FPAE-3B-3.0-PD membrane still maintains about 94% and 93% of its initial IEC and conductivity after being immersed in a 1 M aqueous KOH solution at 80 °C for 600 h. The change in the chemical structure of the AEM before and after the alkaline stability test is negligible, as noted by 1H NMR. Furthermore, the single cell using FPAE-3B-3.0-PD has a highest power density of 156 mW cm−2 at a current density of 350 mA cm−2 at 80 °C.