One year operation of an anion exchange membrane water electrolyzer utilizing Aemion+® membrane: Minimal degradation, low H2 crossover and high efficiency

Using a highly ion conductive, chemically stable, mechanically robust, reinforced anion exchange membrane (AEM) of nominal thickness 85 μm, we report an AEM water electrolyzer operating for longer than one year at 70 °C with 1 M KOH electrolyte, with H₂ crossover below industrial limits. The minimal degradation observed is due to the membrane-electrode-assembly and not due to the membrane, which exhibits negligible change in its ionic conductivity after >1 yr operation. A minimal hydrogen crossover from cathode to anode of <0.4% was also measured for a second cell running for 5000 h (>7 months). This study shows that future research towards zero gap alkaline water electrolyzers should be directed to the development of active and stable catalysts and the formation and integration of stable catalyst layers tailored to AEM water electrolyzers.