Alkali doped polybenzimidazole membrane for high performance alkaline direct ethanol fuel cell

An anion exchange membrane for alkaline direct ethanol fuel cell (ADEFC) was prepared by doping KOH in polybenzimidazole (PBI) membrane. The distributions of nitrogen, oxygen and potassium in the membrane were analyzed by means of XRD and SEM-EDX, respectively. It was found that free or combined KOH molecules may exist in the PBI matrix, which was helpful for the ionic conductivity of PBI/KOH. Ethanol permeability through this membrane was much lower than that of Nafion®. For ADEFC based on this PBI/KOH membrane electrolyte, the power density was 3 to 6 times of the results in literatures. In addition, the micro-structure of alkali doped PBI and the interaction between KOH and PBI matrix were also speculated logically.