Challenges associated with measuring the intrinsic electrical conductivity of carbon paper diffusion media

In this work, an overview of three different through-plane resistivity measurement methods accompanied with the in-plane resistivity measurement method is given and the methods thoroughly evaluated. It is found that the accuracy of the results is highly dependent on the measurement method. The gold coated electrodes reduce the electrical contact resistance (ECR) emerging between the electrodes and the GDL samples; however, it does not completely eliminate it. Measurement of the voltage drop across the GDLs directly on the GDL surfaces excludes contact resistances to the electrode. On the other hand, we find that the difference in the isolation area around the direct voltage-sense-probes in combination with the in-plane resistivity of the GDLs impacts the accuracy of the experimental results. Consequently, implementation of the direct voltage-sense-probes is recommended for accurate measurements with an isolation area as small as possible.