Comparison of conductivity measurement systems using the example of nafion and anion exchange membrane

Abstract Two commercially available systems (BT112 by Bekktech LLC and MK3 by FuMA-Tech-GmbH) for determining the ion conductivity of ion exchange membranes are evaluated. Both systems contain a 4-electrode in-plane conductivity cell that can be heated and humidified during the experiment. Except that measurements in the MK3 system are conducted in ambient air but in a closed system, whereas the Bekktech cell is open to ambient pressure and humidified nitrogen is provided to the cell. Prior to measurements the BT112 system was evaluated with Nafion 115 to optimize system parameters. Results for Nafion 212 and a commercial anion exchange membrane achieved with both systems are compared. Ion conductivities were recorded at different temperatures with variation of the relative humidity. Conductivity values increased with elevated temperatures and higher water content of the membrane as expected, but deviations between the two systems became evident.