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 × 10−2 S cm−1 at 160 °C. ► The composite membranes show good PIL retention ability.