Synthesis and characterization of a new anion exchange membrane by a green and facile route

A new anion exchange membrane was synthesized by a green and facile route---chemically grafting polybenzimidazole (PBI) membrane with BrCH2CH3. The obtained membrane was characterized by means of ex-situ and in-situ tests (EDX, FTIR, AC impedance, single cell test and so on). The results suggested that the group of –CH2CH3 was successfully grafted onto N atom within PBI backbone, while with Br− as counter ion. The corresponding ionic conductivity and ethanol permeability were about 0.022 Scm−1 and 5.24 × 10−8 cm2s−1, respectively. Finally, single cell test suggested that air-breathing alkaline direct ethanol fuel cell with quaternized PBI membrane can deliver a peak power density of about 11 mWcm−2 even at ambient temperature of 13 °C, which was better than those of air-breathing alkaline direct methanol fuel cell in literatures. In addition, a possible reaction mechanism was also proposed and discussed.