Abstract
Carbon Dioxide management is essential to the development of Direct Methanol Fuel Cell Anode. CO
2
bubbles evolution at the anode can create large mass transport loss and block the sites where the triple phase boundary occurs for the electrochemical reaction. The gas can be trapped in the Gas diffusion layer (GDL) and block the channels from the incoming fuel [1-2]. Researchers have studied the mechanism and the dynamics by visualizations of how CO
2
bubbles evolve from the catalyst layers [3-5]. Some studies have been done to the anode structure to improve the performances by modifying the material, wettability, porosity and thickness [6-8]. However, disagreements have been confirmed from different design aspects to whether those modifications reduce the mass transport loss or not [9-11]. In this study, pathways/perforations were created by laser perforating the Gas Diffusion layer (GDL) to enhance the mass transport from and to the catalyst layer. Results have shown superiority of the perforated GDL over the conventional GDL. Further optimization of the perforation diameter, the spacing along the lateral and channel directions have been accomplished. First, the perforation diameter size was investigated with minimum number of holes, 16 holes, spaced with 2 millimeters in lateral and channel directions over the 1 cm
^2
active area of the electrode, as can be seen in Figure 1A. The 60-micron diameter showed little improvement over the virgin GDL while further increase of the diameter caused massive mass transport loss. Secondly, further optimization of the spacing in the lateral and channel directions in Figure 1B, it was found that the 60-micron diameter with 1 millimeter in lateral spacing and 2 millimeter in channel spacing increased the maximum power density by roughly 30% compared to virgin GDL.
Figure1: A) Different perforation diameter ranging from 60-500 micron with 16 holes; B) Spacing optimization in lateral and channel directions.
Figure 1