Chemically & physically stable crosslinked poly(aryl-co-aryl piperidinium)s for anion exchange membrane fuel cells

Poly(aryl-co-aryl piperidinium) (c-PAP) copolymers have recently demonstrated great successes in anion exchange membranes (AEMs) and ionomers for AEM fuel cells (AEMFCs). Here, we present a series of in-situ styrene-crosslinked c-PAP (x-PAP-PS) membranes to further enhance the mechanical strength, dimensional stability, and water retention capacity of c-PAP AEMs. Specifically, x-PAP-PS AEMs simultaneously possess high ion conductivity (>150 mS cm−1), tensile strength (>80 MPa), and chemical and mechanical durability (~90 % ion conductivity and mechanical strength maintaining in 1 M NaOH at 80 °C for 2160 h). Additionally, x-PAP-PS-based AEMFCs reached peak power densities (PPDs) of 2.23 W cm−2 in H2–O2 and 1.32 W cm−2 in H2-air at 80 °C. Importantly, compared to pristine c-PAP AEMs, x-PAP-PS AEMs display higher water retention capacity at low relative humidity (RH), and the corresponding AEMFCs reach PPDs >1 W cm−2 with Pt/C at 30 %/30 % RH at 90 °C. Moreover, the x-PAP-PS-based AEMFCs can be operated stably under a 0.4 A cm−2 current density at 60 °C for ~120 h.