Effect of cathode flow field configuration on the performance of flowing electrolyte-direct methanol fuel cell

Abstract

A major challenge in direct methanol fuel cells is the crossover of methanol, from the anode to the cathode. The flowing electrolyte (FE) concept is one potential method to reduce or eliminate the effects of this problem, and the corresponding fuel cell is known as a flowing electrolyte – direct methanol fuel cell (FE-DMFC). In this study, the effect that the cathode flow field has on the performance of the FE-DMFC was investigated in a COMSOL Multiphysics environment. Methanol concentration, oxygen concentration, pressure distribution and velocity distributions were simulated for a single serpentine, parallel serpentine, triple serpentine and a grid type flow field configuration. The results of this study demonstrate the importance of the velocity distribution on the oxygen transport and its impact on the fuel cell's performance. As such, of the tested flow fields, the grid flow field obtained the lowest performance due the formation of locally low concentration zones (or dead zones) causing an increase in the cathode's concentration polarization. The single serpentine flow field on the other hand provided the best performance due to the better reactant coverage over the CCL.