// MEAs for fuel cells with increased operating temperatures

The power density of direct-methanol fuel cells (DMFC) increases considerably with temperature. For this reason, it is preferable to raise the operating temperature range for DMFCs to 130-150 °C. The perfluorinated sulphonic acid membranes typically used today are no longer stable in the resulting operating conditions when in contact with aqueous methanol solutions. There are also high losses as a result of the methanol crossover. New polyaryl polymers developed by the project partners have an extended stability window. However, this makes it more difficult to apply the catalyst layer in the electrodes. Furthermore, polyaryl polymers are only soluble in flammable or toxic organic solvents.

In the project, a new water-based composition was developed for manufacturing more powerful electrodes on polyaryl membranes. By using detergents, a stable, water-based dispersion was produced from the ionomer solution in organic solvents, which was then processed with a catalyst powder to form a dye and sprayed onto a dry electrolyte membrane. By optimising the dye composition and the processing parameters, it was possible to produce electrodes that displayed improved behaviour at high current densities relative to alternative anodes.

Contact

Dr. Ludwig Jörissen
+49 (0)731 95 30-605
Comparison of the current-potential curves of DMFC anodes with different compositions. ZSE/ECG