Preparation and characterization of fluorine-containing polybenzimidazole/imidazole hybrid membranes for proton exchange membrane fuel cells

Polybenzimidazole (PBI)/imidazole (Im) hybrid membranes were prepared from an organosoluble, fluorine-containing PBI with Im. The thermal decomposition of the PBI/Im hybrid membranes occurred at about 160 °C. The conductivities of the acid doped PBI/Im hybrid membranes increased with both the temperature and the Im content. The conductivity of acid doped PBI–40Im (molar ratio of Im/PBI = 40) reached 3.1 × 10−3 (S/cm) at 160 °C. The proton conductivities of PBI/Im hybrid membranes were over 2 × 10−3 (S/cm) at 90 °C and 90% relative humidity. The addition of Im could reduce the mechanical properties and methanol barrier ability of the PBI membranes.