Robust Anion Exchange Membranes for Alkaline Fuel Cell Applications

Anion exchange membranes (AEM) can provide high ionic conductivity and facilitate enhanced transport phenomenon. However, one challenge is in the development of mechanically robust thin films. Chemical and mechanical degradation of thin films can lead to failure in fuel cells. In this study, an engineering polymer was used as the polymer matrix and blended with a polymer that could be functionalized into an AEM. Commercially available polymers were used as both components in these blends. Blend miscibility was examined using rheology and mechanical characterization. A prediction of the membrane integrity and its lifetime were measured under different hydration levels and humidity cycling. Dynamic mechanical testing of membranes was conducted using TA instruments ARES G2 instrument at a range of temperatures (30-90^oC) and relative humidities ranging from 0-95% RH. Moduli changes with varying humidity saturation levels and temperatures are analyzed to understand the membrane mechanical characteristics. ‘Water stress’ tests are performed on the membranes to study tension and durability by quantifying the elongation at break during reversible water absorption-desorption cycles. In addition to the mechanical property assessments, the electrochemical conductivity was also studied. Various analytical and morphological techniques such as DSC, TGA, XRD, SAXS and FTIR were used to predict the performance and stability of the blend membranes. The microstructure analyses of the results were developed to understanding of the micro and nanoscale phase behavior of the membranes.