3D Membrane Electrode Assemblies (MEAs) for Direct Methanol Fuel Cells (DMFCs)

Passive Micro-Direct Methanol fuel cells (micro-DMFCs) can be the power supply solution for the next generation of handheld devices if high volumetric power densities can be achieved. One approach to improve the volumetric power density of passive DMFC designs is to increase the reactive area without a corresponding increase in overall volume by patterning MEAs with corrugated 3-D geometries. In this paper, geometric analysis is presented that demonstrates significant active area gain in fuel cell MEAs patterned with high aspect ratio corrugations. A thermoforming process was used to pattern MEAs with 3-D corrugated geometries using aluminum molds. In order to perform functional tests on 3D corrugated MEAs, the fuel and oxidant reservoirs have been redesigned to accommodate the special packaging requirements of the 3D MEAs. Electrodes were modified to serve as the current collectors and also provided backing layers for catalyst. The simplified design avoids the large clamping force and high strength requirements of the endplate material in order to minimize the electrical contact resistance between the electrodes and the current collectors. Finally, the potential power density gain from the 3D MEAs is illustrated.