Water Crossover Reduction in DMFC Utilizing Hydrophobic Anode MPL

Reducing the water crossover from anode to cathode is an important goal for direct methanol fuel cell (DMFC) technology, especially if highly concentrated methanol fuel is to be used. A well-documented way to reduce this water loss to the cathode side is by using a hydrophobic cathode microporous layer (MPL). Recently, however, it has been demonstrated that in addition to a cathode MPL, the use of a hydrophobic anode MPL further reduces the water loss to the cathode. In this work, we use a two-phase transport model that accounts for capillary induced liquid flow in porous media to explain physically how a hydrophobic anode MPL acts to control the net water transport from anode to cathode. Additionally, we perform a case study and show that a thicker, more hydrophobic anode MPL with lower permeability is most effective in controlling the net water transport from anode to cathode.