Vapor feed direct methanol fuel cells (DMFCs): A review

Direct methanol fuel cells (DMFCs) are attractive portable energy source for several applications like mobile phone and notebook PCs charging, however the various critical challenges, limit the widespread commercial application of these DMFCs. A review of the experimental and numerical studies on the vapor feed DMFCs is conducted. The critical challenges of a vapor feed DMFC are methanol crossover (MCO), water management layer (WML), carbon dioxide release and operation at high temperature have been discussed and analyzed in detail. It is shown that the critical challenge regarding to the MCO is how to feed vapor methanol with minimum MCO through the membrane so that the cell performance can be maximized. The several methods related to the WML deals with transport of the water produced on the cathode to the anode through the membrane and helps to operate the anode with vapor methanol and the cathode with minimum water flooding. The critical challenge related to the high temperature vapor feed DMFC is the selection of the membrane electrode assembly (MEA) materials so that it can be operated at high temperature which critically affects the cell performance. The various vaporization methods of the liquid methanol supplying to DMFC have been discussed in detail. The recent developments in the stacking of vapor feed DMFC to increase the power density have also been discussed. Based on the literature surveys, a statistical flow chart is proposed to optimize a passive vapor feed DMFC with concentrated methanol.