Characteristics of heat and mass transport in a passive direct methanol fuel cell operated with concentrated methanol

In this work, the effect of cell structure on the overall cell performance as well as the heat and mass transport in a passive direct methanol fuel cell (DMFC) operated with concentrated methanol solution is experimentally investigated. The influences of the anode methanol vapor transport layer (VTL) and cathode water management layer (WML) are examined. The variations of cell temperature under different working conditions are also recorded. The results show that both the anode VTL thickness and cathode WML thickness greatly influence the cell performance and the species transport in the cell, which should be carefully optimized. Also, it is shown that the difference between the stable cell temperature under the open circuit condition and that under constant voltage discharging condition is quite small for a passive vapor-feed DMFC operated with concentrated fuel. Theoretical analysis and experimental results show that the transport resistance of methanol in the membrane electrode assembly (MEA) is much smaller than that in the other anode components of the cell structure.