Effect of the current collector design on the performance of a passive direct methanol fuel cell

Abstract The design of the current collectors (CCs) used in fuel cells is crucial as it affects the energy density generated from these systems. This is due to the fact that different designs will lead to different charge, heat and mass transport phenomena. Therefore, towards the optimization of these devices, it is required to have a deep knowledge of the effect of the CC geometry on the cell performance. The present work intends to evaluate that, by studying the effect of the anode and cathode CC configuration on the power output of a passive direct methanol fuel cell (pDMFC) operated at ambient conditions. Three different perforated CCs, each one with a different open ratio, and an open window frame CC were tested at both anode and cathode sides. The pDMFC performance was evaluated through the polarization and power density curves and the experimental results were explained under the light of the electrochemical impedance spectroscopy (EIS) measurements. At this point we introduced an innovative electric equivalent circuit allowing the identification of the different losses, including the activation resistance of the parasitic cathode methanol oxidation. The best power output, 3.14 mW/cm 2 , was achieved with the perforated CC with the lower open ratio (34%) on both sides and feeding the cell with a methanol concentration of 2 M.