On the stability of anion exchange membrane fuel cells incorporating polyimidazolium ionene (Aemion plus ®) membranes and ionomers

We report the anion exchange membrane fuel cell (AEMFC) performance using commercial, polyimidazolium-based, Aemion+(R) as both the ionomer and membrane. Aemion+(R) affords reduced dimensional swelling yet higher water permeance compared to previously reported polybenzimidazolium-based Aemion (R) membranes and ionomers. Non-reinforced Aemion+(R) is shown to enhance the properties of Aemion (R) membranes, and Aemion+(R) reinforced with a fluorine-free polyolefin substrate is shown to enhance the properties considered important to fuel cell operation with respect to non-reinforced analogues. The highest AEMFC power density of 1.4 W cm(-2) at 70 degrees C, 250 kP(abs) H-2/O-2 was obtained by using a direct membrane deposition (DMD) approach, where an ultrathin 5 mu m membrane increased the voltage stability through enhanced water permeation, allowing characterization under these conditions. However, the reinforcement was found to be pivotal in enabling stable AEMFC operation at 80 degrees C, where a 10 mu m-thick reinforced Aemion+(R) provided 1.1 W cm(-2) power at 80 degrees C, 300 kPa(abs) H-2/O-2. The degradation properties of this material under varied cell temperatures, current densities and RHs are finally examined.