Synthesis and Physical Behavior of Model Polymer Electrolyte Membranes for Alkaline Fuel Cells

Alkaline fuel cell (AFC) technology holds significant promise for portable power supplies because AFCs are very efficient at temperatures under 200\r{ }C, but also because AFCs can use relatively inexpensive, non-noble metals (Ni, Fe, Co) as the catalyst material. Wide-spread use of the AFC has been prevented by the use of aqueous KOH liquid as the electrolyte, which is easily poisoned by the formation of K$_{2}$CO$_{3}$. Development of an semipermeable polymeric alkali anion exchange membrane (AEM) would significantly improve the usefulness of AFCs by eliminating carbonate poisoning and the engineering problems associate with a liquid electrolyte. We have been exploring model copolymers containing phosphonium cations as candidate materials for AEMs. Recent findings on the transport properties and stability of random copolymers of styrene and p-vinylbenzyl-trimethylphosphonium chloride will be presented, as well as ongoing efforts to study the effect of polymer morphology on transport and stability in ionomers based on both phosphonium and ammonium cations.