Constructing micro-phase separation structure to improve the performance of anion-exchange membrane based on poly(aryl piperidinium) cross-linked membranes

The ether-bond-free poly(biphenyl piperidine)s are prepared to improve the alkaline stability of the anion exchange membrane (AEMs). At the same time, the construction of micro-phase separation structure is a good way to solve the “trade-off” problem between ionic conductivity and stability of AEMs. In this study, we report a new method for constructing micro-phase separation structures based on “main-chain type” AEMs and a crosslinking strategy that does not sacrifice ion exchange capacity. A series of poly(biphenyl piperidine)s AEMs (PAP–OH–x) are prepared by introducing 2-bromoethanol and 1,6-dibromohexane to form piperidine cationic groups and cross-linked structure. The structure of hydrophilic/hydrophobic phase separation is confirmed by TEM images. The cross-linked membrane of poly(biphenyl piperidine)s (PAP–OH–8%) membrane exhibits high conductivity of 0.081 S/cm with a rational water absorption (55.6%) and low swelling ratio (11.8%) at 80 °C, and also preserves the hydroxide conductivity (89.2% retention) after testing in a 5 M NaOH aqueous solution at 80 °C for 30 days, exhibits high alkaline stability. Furthermore, a single H2/O2 fuel cell with poly(biphenyl piperidine)s (PAP–OH–8%) membrane exhibits the open circuit voltage of 1.02 V and the peak power density of 290 mW/cm2 at 60 °C.