Alkali doped polybenzimidazole membrane for alkaline direct methanol fuel cell

An anion exchange membrane for alkaline direct methanol fuel cell (ADMFC) was prepared by doping polybenzimidazole(PBI) membrane with KOH. The obtained membrane was characterized by means of XRD, TGA–DTA, AC and so on. The results suggested that it possessed satisfying thermal stability and comparable mechanical strength with acid doped PBI. At room temperature, methanol permeability through this membrane was one order of magnitude lower than that of Nafion® membrane, while its ionic conductivity was comparable with that of other anion exchange membranes in literatures. For ADMFC at 90 °C based on this PBI/KOH membrane electrolyte, the peak power density was about 31 mW/cm2, which was significantly improved mainly due to this membrane's high thermal stability, fast kinetics of electrochemical reactions and lower methanol permeability.