PEMFC electrode preparation by electrospray: Optimization of catalyst load and ionomer content

Electrodes for proton exchange membrane fuel cell (PEMFC) have been prepared by means of electrospray deposition, using different ionomer contents and catalyst loads. The electrodes have been mounted in single PEMFC, and tested as cathode. The electroactive platinum area of electrosprayed electrodes has been measured by the hydrogen underpotential deposition method. Polarization curves have been measured to determine the optimal concentration for the platinum catalyst (Pt/C, 20 wt.%) and the ionomer (Nafion®). Best performance is observed with 15% ionomer content in the electrosprayed cathode due to minimal cell internal resistance. This optimal concentration is lower than that found for electrodes prepared by other standard methods, like airbrushing or impregnation, which is attributed to the improved ionomer distribution within the electrospray deposited catalyst layer. On the other hand, the optimum value for catalyst load is similar to that encountered for electrodes prepared by the other methods, which reflects that electrospray has little or no effect neither on the catalyst nor on the electronic resistance of the catalyst layer.