• Reissner, Regine

Abstract

The main problem for future fuel cell commercialisation is the cost of membrane–electrode assembliesMEAssatisfying both powerdensityandlifetimerequirements.AtDLR,low-costMEAproductiontechniquesarebeingdeveloped.ThesenewMEAsarecharacterisedandinvestigatedwithphysicalandelectrochemicalmethodsinordertostudythepowerlossprocesses,thelifetime,thereaction mechanisms and in support of MEA development. The possibilities for the characterisation methods used will be demonstratedby various examples. At DLR, a new production technique based on the adaptation of a rolling process is developed for fuel cell electrode.and MEA preparation. After mixing the dry powder electrode material in a mill, it is blown onto the membraneor backingresulting in auniformly distributed layer. This reactive layer is fixed and thoroughly connected to the membrane by passing them through a calender. Inorder to produce the second electrode, the same steps are repeated. This procedure is very simple and, as a dry process, avoids the use ofany solvents and drying steps. We have achieved a thickness of the reactive layer as low as 5mm, reducing the amount of catalyst neededand,thus,thecosts.Electrochemicalinvestigationshaveshownaperformancecomparabletothatofcommercialelectrodes.The.degradationofMEAforpolymermembranefuelcellPEFCcomponentsduringthecell’slifetime,yieldsachangeintheelectrochemical behaviour. The characterisation of PEFC MEA-components after electrochemical operation has given information aboutthe degradation of electrodes and membranes and about the change in the platinum distribution on the anode, whilst on the cathode, theplatinum content is unchanged.

Topics

• impedance spectroscopy
• polymer
• Platinum
• drying