Combined local current distribution measurements and high resolution neutron radiography of operating Direct Methanol Fuel Cells

The current and fluid distribution in Direct Methanol Fuel Cells (DMFCs) was investigated in situ by means of combined high resolution neutron radiography and locally resolved current distribution measurements. The used neutron radiography set-up allows high spatial resolutions down to 70 μm at the full test cell area. A local formation of water droplets in the cathode flow field channels could be observed. Strongly inhomogeneous current distributions during cathodic flooding processes result in a performance loss of up to 30% of the initial value. Single CO₂ bubbles can be observed at low current densities. The water and current distribution during bi-functional operation of a DMFC was measured for the first time.