D.P. Leonard, S. Adhikari, K.H. Lim, E.J. Park, Y.S. Kim
Los Alamos National Laboratory,
Keywords: fuel cell, water electrolysis, anion exchange membrane, anion exchange polymer
Summary:There has been rapid development and increasing interest in the area of electrochemical devices such as fuel cells and electrolysis cells. In addition to the more commonly known proton exchange membrane fuel cells (FC) and water electrolyzers (WE), other chemistries in development are showing significant progress an potential. One such chemistry is anion exchange polymers for membranes and ionomers. The hope is that this chemistry will allow for the combination of high performance cell architectures with lower cost catalysts and materials and lead to less expensive hydrogen production and utilization. In the decade since anion exchange membrane fuel cells (AEMFCs) were originally demonstrated their reported peak performance has increased from 0.3 W/cm2 to > 3 W/cm2. While high performance has been achieved, understanding the complicated relationship that catalyst/ionomer interactions, water-management, and hydroxide conductivity have with performance and durability has been a challenge. To improve the understanding these relationships we have developed quaternized poly(fluoroene) aion exchange polymers. These anion exchange polymers have helped reveal the important role that catalyst/ionomer interactions, water-mangament, and hydrophobicity play in AEMFC operation. By utilizing asymmetric membrane electrode assemblies, and controlling the fluorination of the polymer backbone we have seen enhanced performance and durability during fuel cell testing. These anion exchange polymers also show promising performance in WE testing and point to avenues of development that will lead to the production of practical AEMWEs.