Anode-controlled water management in direct methanol fuel cells

A low water crossover from anode to cathode in a direct methanol fuel cell (DMFC) must be realized if highly concentrated methanol fuel is to be used. The use of a low-a membrane electrode assembly (MEA) is vitally important in achieving this goal. The low rate of water crossover for a low-a MEA has traditionally been attributed to the hydrophobic cathode micro-porous layer (MPL), thin membrane combination, but it has recently been discovered that a hydrophobic anode MPL is also effective in reducing water crossover. In this paper we demonstrate that a hydrophobic anode MPL may play an even more significant role than cathode MPL in reducing water crossover, and we embark on developing anodecontrolled water management strategies for DMFCs. As a first step in this process, we show that a thicker, more hydrophobic anode MPL with lower permeability is more effective in reducing water crossover.