Scale-up Parameters for Fuel Cell Catalyst Dispersions and Pilot Scale Layer Formation in indirect Roll-to-Roll Fabrication of Catalyst coated Membranes for Proton Exchange Membrane Fuel Cells

Abstract

In this work, essential scale-up aspects of the fabrication of catalyst coated membranes (CCMs) for hydrogen fuel cells via the indirect decal process are investigated. In this process, the catalyst powder is dispersed with a binder in a liquid, coated and dried onto a decal foil. Finally, the catalyst layer is transferred by calendering onto the membrane to yield a CCM for the application in hydrogen fuel cells. In the past, experiments along this and competitive process routes focused either on the final catalyst layer, or the experiments have been performed on laboratory scale only. The investigations presented in this work aim to close this research gap: the scale-up of the fabrication and processing of semi-finished goods for the production of CCMs via the indirect decal process. Since the scale-up factors of processes with heterogenous process media (like solid-liquid dispersions) are typically small, experiments on a pilot scale are in place.

In a first step, the adsorption kinetics of the binder onto the catalyst surface are investigated to define the decisive process variables, time and temperature, of the dispersion preparation. Secondly, the agitation mechanics for the non-Newtonian catalyst dispersion are studied in a proper setup and a viable workflow is established. Finally, the layer formation and performance are investigated both on laboratory as well as on pilot scale. With this work, process variables for the production scale fabrication of CCMs are investigated and established.