A Microporous Polymer with Suspended Cations for Anion Exchange Membrane Fuel Cells

A novel microporous anion exchange membrane containing a spirobiindane segment and cardo moiety is successfully synthesized through superacid-catalyzed Friedel–Crafts-type polymerization. The developed polymer showed good solubility in common polar aprotic solvent and exhibited excellent ionic conductivity (163 mS cm–1 at 80 °C). A series of poly(spirobiindane-aryl ether sulfone) copolymers P(SBI/AES)-X with variable SBI/AES molar ratios were synthesized, and each copolymer exposed different free volumes that increases by increasing the content of spirobiindane in the copolymers. In turn, this free volume of copolymer causes the construction of well-developed ion channels in the developed anion exchange membranes (AEMs). The resulting QP(SBI/AES)-0.5 AEM, with an ion exchange capacity (IEC) of 1.59 mmol g–1, exhibited a high hydroxide conductivity of 110 mS cm–1 at 80 °C as well as good mechanical robustness. The peak power density achieved using a single cell fuel cell test is 593 mW cm–2. The results depicted the excellent potential of the resultant microporous anion exchange membrane in the progress of anion exchange membrane fuel cells.