Abstract
Separate measurement of current density under the different regions of the flow field geometry, i.e. under the land and under the channel, in DMFCs is significant. Such measurements may reveal the mechanisms and the effects of the various coupled parameters that influence the cell performance. Moreover, it can provide guidance for flow field design optimizations and could eventually lead to practical solutions to mitigate methanol crossover and/or its effects. A novel technique is used to directly measure the current density under the land and under the channel separately. In this method, the anode side of the cell is partially catalyzed depending on the area of interest (land, channel or full), whereas the cathode side is always fully catalyzed. The experimental results show that the current density under the land is significantly higher than that under the channel. The drastic difference in performance is attributed to the much higher electrochemical active area (ECA) under the land as shown by CO stripping voltammetry measurements.
