Poly(biphenyl piperidinium)/Poly(vinyl alcohol)-Based Blended Anion Exchange Membrane for Fuel Cell Application

The anion exchange membrane (AEM) and anion exchange ionomer (AEI) have received widespread attention as promising electrolytes for anion exchange membrane fuel cells (AEMFC) and the anion exchange membrane water electrolyzer (AEMWE). However, enhancing hydroxide (OH^-) ion conductivities and alkaline stabilities of AEM and AEI is highly challenging for the commercialization. In this study, a series of poly(vinyl alcohol) (PVA) blended with poly(biphenyl piperidinium) (PBP) was prepared, characterized, and analyzed for its electrochemical performance. Notably, the PBP-PVA-15% membrane reached a maximum OH^- ion conductivity of 122.6 mS cm^-1 whereas the pristine PBP membrane reached 65.2 mS cm^-1 at 90 °C. In a H₂/O₂ AEMFC test, the membrane electrode assembly (MEA) based on the ultimate PBP-PVA-15% membrane achieved the maximum peak power density (PPD) of 420.3 mW cm^-2 with a current density of 914.2 mA cm^-2, whereas the pristine PBP membrane achieved a PPD of 315.2 mW cm^-2 with a current density of 685.5 mA cm^-2. These results demonstrate that PBP-PVA blended AEMs are reliable electrolytes for use in AEMWEs and AEMFCs.