Macromolecular protic ionic liquid-based proton-conducting membranes for anhydrous proton exchange membrane application

► We synthesize anhydrous proton-conducting composite membranes based on macromolecular protic ionic liquids (PILs). ► We characterize the resultant composite membranes. ► The composite membranes show proton conductivity up to 1.2×10−2Scm−1 at 160°C. ► The composite membranes show good PIL retention ability. A type of anhydrous proton-conducting membranes are prepared via in situ cross-linking of polymerizable oils containing polyamidoamine (PAMAM) dendrimer-based macromolecular protic ionic liquids (PILs). The resultant composite membranes are transparent, flexible, and thermally stable up to 350°C. Under anhydrous conditions, the macromolecular PIL-based membranes show proton conductivity of 1.2×10−2Scm−1 at 160°C, which is higher than that of the membranes containing small-molecule PILs. Furthermore, the macromolecular PIL-based composite membranes have much better PIL retention ability than which containing small-molecule PILs. These properties make this type of macromolecular PIL-based membranes suitable for high-temperature anhydrous polymer electrolyte membrane fuel cells.