Enhancing anion conduction stability of quaternized poly(phenylene) oxide‐based anion exchange membranes with ionic liquids modified carbon nanomaterials

The anion exchange membrane (AEM) with high and stable conductivity is important to the commercial application of anion exchange membrane fuel cell. The AEM based on the polymer of quaternized poly(phenylene) oxide (QPPO) with enhanced anion conduction stability has been constructed through the introduction of the ionic liquid (IL) of 1-aminopropyl-3-methylimidazolium bromide (APMIMBr)-modified carbon nanomaterials, such as carbon nanotubes oxide (OCNT) and graphene oxide (GO) nanosheets. The IL-OCNT and IL-GO composites prevented hydroxyl groups from attacking the polymer of QPPO. Thus, QPPO/x(IL-OCNT) and QPPO/x(IL-GO) series membranes possessed enhanced hydroxide conductivity stability in alkaline solution. Specifically, QPPO/5%(IL-OCNT) and QPPO/5%(IL-GO) membranes exhibited the hydroxide conductivities of 23.0 and 28.5 mS/cm at 80°C. Notably, the hydroxide conductivities could reach 16.3 and 30.2 mS/cm while the prepared membranes were immersed in 2 M KOH solution for 1848 h. Furthermore, the stable hydroxide conductivity was derived from the fine dimension stability and mechanical property. The tensile stress values were, respectively, 19.4 and 19.8 MPa even if the membranes were immersed in alkaline solution. In the prepared QPPO/x(IL-OCNT) and QPPO/x(IL-GO) membranes,