Polybenzimidazole membranes chemical stability

In this area of solid polymer electrolytes, polybenzimidazole (FBI) doped with KOH has to be mentioned, as it (Fig. 5.5) is known for its high thermal and chemical stability, even if it is not water soluble, which is desired for ion-solvating polymers [61-65]. Ionic conductivities between 5 X 10 and 1X 10 S/cm were obtained for FBI using KOH with a concentration of 6 M at 70-90°C [65]. These membranes were assembled with commercial electrodes from E-Teck and the resulting MEA was then incorporated into a single cell. The performance in a H2/O2 fuel cell test was reported and a current of 620x 10 A/cm at 0.6 V was obtained. However, measurements were performed at 50 °C under pressurized H2 and O2, which results in a significant improvement in performance compared with the use of nonpressurized fuels [65]. 

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