// Direct methanol fuel cells

 

Operation of MT-DMFC stacks at atmospheric cathode pressure

As part of the “Development of innovative MEA components for MT-DMFC operated at atmospheric cathode pressure” project funded by “The German Federation of Industrial Research Associations” a medium temperature direct methanol fuel cell (MT-DMFC) stack was developed for operation at 130 °C and adapted to the special requirements at atmospheric cathode pressure.

One goal of the project is to combine the high performance of DMFC at high operating temperatures with the system engineering requirements of low cathode pressure, to achieve high overall system efficiency. In addition to the development of electrodes, extensive cell and stack development activities were carried out with the aim of designing a high-performance cell adapted to the particular conditions mentioned above.

A corresponding cathode flow field was developed (see figure 1) following extensive experimental and CFD simulation activities. This flow field exhibits significantly elevated oxygen concentration in the reaction layer and only slightly increased differential pressure. The distribution field was converted into an embossable version, and its performance was validated using a four-cell stack (see figure 2). In combination with a non-fluorinated membrane developed by the project partners, the stack exhibits a maximum power density of more than 0.15 W/cm² when operated with methanol at atmospheric cathode pressure.

Contact

Dr. Joachim Scholta
+49 731 9530-206
Fig. 1: Oxygen mole fraction in the MPL at 600 mA/cm². Inflow upper right, outflow lower left. Standard flow field (left), optimized flow field (right).
Fig. 1: Oxygen mole fraction in the MPL at 600 mA/cm². Inflow upper right, outflow lower left. Standard flow field (left), optimized flow field (right).
I-V characteristics for 4-cell stack with 100 cm² active area. T= 130°C,  p anode = 2.8 bar (abs), p cathode = 1 bar (abs), λ(CH3OH)= 2, λ(air)= 4
Fig. 2: I-V characteristics for 4-cell stack with 100 cm² active area. T= 130°C,
p anode = 2.8 bar (abs), p cathode = 1 bar (abs), λ(CH3OH)= 2, λ(air)= 4