Investigation of fuel cell catalyst dispersion formulations for indirect roll-to-roll fabrication of catalyst coated membranes for proton exchange membrane fuel cells

In this work, the viability of the indirect process route for the fabrication of catalyst coated membranes for hydrogen fuel cells is demonstrated. This route involves a catalyst dispersion that is cast onto a decal foil before calendering the subsequently obtained dry layer onto a membrane. Three different formulations for the catalyst dispersion were investigated. The results from observations along the whole process chain indicate that these formulations have a strong influence on the dispersion properties, as for the transferability from the decal foil to the catalyst layer and finally the performance of the catalyst in a fuel cell. Remarkable performance was achieved in the electrochemical testing in a realistic scenario with the catalyst layer from a low-viscous dispersion, with a high ionomer-to-catalyst and high alcohol-to-water ratio. The performance was on the same level of a high performance commercially available reference between 0 A/cm 2 at open circuit potential of 0.964 V for the CMC prepared in this study and 0.931 V for the commercial reference respectively and up to 2 A/cm 2 at 0.67 V cell voltage. Future potential for optimization lies in the preparation of the catalyst dispersion and calendering step that shapes the pore structures of the catalyst layer and consequently impacts the electrochemical performance. • Indirect process route feasible for CCM production. • Optimized dispersion formulation and in-depth characterization. • Equivalent to commercial performance, reduced Pt loading. • Comprehensive microstructural properties of catalyst layers characterized. • Centrifugal adhesion analysis for catalyst transfer.