Bis-imidazolium-based anion-exchange membranes for alkaline fuel cells

Novel anion-exchange membranes (AEMs) are prepared via in situ cross-linking of styrene, acrylonitrile and the bis-imidazolium functionalized ionic liquid monomer, 1-allyl-3-(6-(1-butyl-2-methylimidazol-3-ium-3-yl)hexyl)-2-methylimidazol-3-ium bromide ([ABMHM][Br]2), and followed by anion-exchange with hydroxide ions. The morphology and characteristic properties of the resultant copolymer membranes, such as the water uptake, swelling ratio, ion exchange capacity (IEC), hydroxide conductivity, and chemical stability are investigated. The membrane containing 40% mass fraction of [ABMHM][OH]2 shows hydroxide conductivity up to 2.0×10−2 S cm−1 and good long-term stability in 1 M KOH solution at 60 °C. The results of this study suggest that the AEMs based on bis-imidazolium cations have good perspectives for alkaline fuel cell applications.

Graphical abstractAlkaline bis-imidazolium-based anion-exchange membranes show good alkaline stability up to 30 days in 1 M KOH at 60 °C.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We synthesize bis-imidazolium functionalized ionic liquid monomers. ► We prepare bis-imidazolium-based anion-exchange membranes. ► The membranes show a hydroxide conductivity up to 2.0×10−2 S cm−1 at 60 °C. ► The membranes show an excellent chemical stability.