Study of membrane electrode assemblies for PEMFC, with cathodes prepared by the electrospray method

The electrospray deposition of platinum supported on carbon (Pt/C) particles has been used for the preparation of electrodes for proton exchange membrane fuel cells (PEMFCs). The departing suspensions contain the Pt/C electrocatalyst together with an ionomer (Nafion®) and a solvent. Two types of solvent have been used, isopropanol and a mixture of butylacetate, ethanol and glycerol (BEG). The microscopic characterisation of electrosprayed films shows the electrospray deposited Pt/C films with a dendritic morphology. XPS analysis of the films reflects changes in the ionomer component after electrospray deposition. A decrease in the signal corresponding to backbone chain (CF2) is observed on the films deposited with the low evaporation temperature solvent (isopropanol), indicating some disruption of ionomer chains during the electrospray process. With high evaporation temperature solvent (BEG), the disruption effect seems less acute. Membrane electrode assemblies were prepared with the electrosprayed electrodes as cathodes. Good general performance is encountered, comparable with standard commercial cathodes. Electrosprayed electrodes prepared from high evaporation temperature solvent (BEG) show a higher surface specific area. The internal resistance is something higher for MEAs with electrosprayed cathodes. The long term stability test shows a performance loss of about 10 μV h−1 over 700 h continuous testing.