Pendent piperidinium-functionalized blend anion exchange membrane for fuel cell application

Abstract Alkaline anion exchange membrane fuel cell has fast cathode reactions and thus allows the use of low cost electrocatalysts. However, its practical application is hindered by the low hydroxide ion conductivity and alkaline stability of AEM. In this study, pendent piperidinium functionalized polyetheretherketone is synthesized and blended with polybenzimidazole for fabrication of composite anion exchange membrane. The pendent piperidinium functionalized side chains can create well-connected ionic transporting channels and thus impart the blend membranes high hydroxide conductivity (61.5–72.8 mS cm −1 at 80 °C) and good tensile strength (42.8–58.9 MPa). Due to the strong interactions between polybenzimidazole and piperidinium groups of the polymers as confirmed by Fourier transform infrared spectroscopy, the piperidinium functionalized blend anion exchange membrane can retain 95% of its original OH − conductivity value when treated in 1 M KOH at 60 °C for 576 h. The single fuel cell assembled with the membrane can yield a peak power density of 87 mW cm −2 at 80 °C. Our work provides a new and effective method to balance the hydroxide conductivity and alkaline stability of anion exchange membranes.