Fuel cells based on alkaline exchange membranes (AEM) have garnered increased interest because of their inherent advantages over traditional proton exchange membranes (PEM). High pH operating conditions allow for more facile reaction kinetics, reduced platinum-group metal catalyst, and reduced fuel crossover issues. Moreover, these materials can be made from inexpensive precursors which can further drive down the cost of the membrane electrode assemblies (MEA) for fuel cells.

In this study, a variety of block copolymer AEMs based on based on vinyl addition and ring-opening metathesis polymerization of norbornenes was synthesized and characterized. Correlations were found between the ionic conductivity and mechanical properties and the polymer structure, channel size and phase separation. The AEMs were also used to construct MEAs for alkaline fuel cells and their performance was analyzed using electrochemical impedance spectroscopy.

Financial support provided by the ARPA-E IONICS program for G.H. and M.M. is gratefully acknowledged.