Increasing the Ion Conductivity by Modification of Anion Exchange Membranes for Alkaline Fuel Cells

Abstract

Optimisation of anion exchange membranes provides a high potential for overcoming remaining challenges of alkaline fuel cells. The modification of the polymer structure by incorporation of additives allows a specific adaption of membrane properties such as ion conductivity. Glucose, ortho-dichlorobenzene (ODB) and silica particles were tested as additives to modify a commercially available membrane. An optimised amount of additive was crucial to obtain a mechanical stable membrane. The morphology of the modified membranes was studied by scanning electron microscopy showing a porous structure for the ODB modified membrane. Electrochemical impedance spectroscopy measurements, over a wide range of temperatures, resulted in increased ion conductivity for all cases. Finally, thermogravimetric analysis coupled to a GC/MS system gave proof of the incorporation of glucose in the membrane. These findings will encourage us to use modified membranes in the preparation and testing of single cells for the alkaline fuel cell.