Sulfonated para-PBI: Application in HT PEMFC, VRFB and AEMWE

Abstract

By adding a sulfonic acid group to para-PBI, the material gains a proton conductive group when doped with phosphoric acid, and can be covalently crosslinked via Friedel-Crafts-type sulfonylation. Ion solvating membranes based on KOH doped PBI have been investigated for use in alkaline water electrolysers using 5-7M KOH feed solutions,[1] but so far could not be applied to anion exchange membrane water electrolysers (AEMWE), which operate with 100 mS/cm) and stability (>6 months tested) in 1M KOH, which allows to substitute AEM in AEMWE.[3]