Anion Exchange Membranes (AEM) can be used in fuel cells and electrolyzers. The benefits include lowering the amount of platinum catalysts, simplifying water management, and improving electrochemical kinetics at the air cathode. However, the performance of AEMs is not as high as that of proton exchange membranes partially because of factors such as low ionic conductivity, poor stability at high pH, and high water uptake.

A series of multiblock copolymers including poly(arylene ether)s and poly(norbornenes) with long head-group tethers were synthesized for use in AEM fuel cells and electrolyzers. In this study, the number of head-groups per block and resulting conductivity, domain size and water uptake was studied. The improvement in performance (increased conductivity and reduced water uptake) was correlated with domain size, bound and unbound water content, and ion channel configuration.

Financial support for L.L. and J.M.A. from US Office of the Deputy Assistant Secretary of the Army for Defense Exports and Cooperation (DASA-DE&C) is gratefully acknowledged. Financial support for M.M. from ARPA-E Ionics program is gratefully acknowledged.