Anion exchange membrane based on alkali doped poly(2,5-benzimidazole) for fuel cell

The properties of alkali doped poly(2,5-benzimidazole) membrane with different alkali doping levels for fuel cell application are reported in this work. The alkali doping level played an important role for the ion conductivity of the membrane. The ion conductivity significantly increased with alkali doping level. The ion conductivity also increased with the temperature. The ion conductivity of the alkali doped ABPBI membrane (alkali doping level = 0.37), reached to 2.3 × 10− 2 S cm− 1 at room temperature and 7.3 × 10− 2 S cm− 1 at 100 °C. The water uptake of the alkali doped ABPBI membrane was increased from 9.1% to 19.2% with increasing alkali doping level at room temperature. The alkali doped poly(2,5-benzimidazole) membrane also showed excellent ion conducting stability and thermal stability as compared with the known quaternized anion exchange membranes.

► Alkali doped ABPBI as anion exchange membrane.
► Ion conductivity of alkali doped ABPBI membrane increases with alkali doping level.
► Alkali doped ABPBI membrane shows better ion conducting stability and thermal stability compared with the quaternized membrane.