With the globally growing market for renewable energy carriers and converters, the scale of material production is increasing, making it necessary to reevaluate processes and parameters of materials. Even though improvements are without doubt still necessary, fuel cells have a high probability to live up to the requirements of the market regarding power density, lifetime, scalability, costs and system simplicity that have to be met in order to enable a broad commercialization.

Especially high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) have clear advantages over other available systems at a comparable technological readiness level. The - in comparison to low temperature polymer electrolyte fuel cells (LT-PEMFCs) - elevated operation temperature increases the tolerance of the platinum electrocatalyst towards gas contamination. This enables a simpler system setup, as extensive gas purification becomes obliterated. Furthermore, the higher temperatures allow a more efficient use of the produced heat, contributing to the overall efficiency [1],[2].

The upscaling of the production of electrodes and membranes for high temperature polymer electrolyte membrane fuel cells, as well as the membrane electrode assembly (MEA) manufacturing post new challenges on product reliability. The choice of production method defines the scalability as well as the product reproducibility.

Different coating processes are feasible for high throughput electrode production, all requiring specific ink properties to ensure sufficient loading and homogeneity. In order to assess the reproducibility and scalability, electrodes based on commercial catalysts are manufactured by spraying, casting and with a slot die process. Electrodes are evaluated in regard to their reproducibility, performance and durability. A new non-destructive method for quality control is introduced. Continuous X-ray scanning of the electrodes allows to determine the Pt loading and distribution over large areas.

Performance and durability are determined during operation with wet reformat, mimicking the gas composition of a methanol reformer. The latest results show degradation rates as low as 1 µV h^-1, calculated from after the initial 50 h up to 3000 h at 0.4 A cm^-2 (Figure 1). The results and experience are used to assess process requirements and scalability.

[1] Q. Li, D. Aili, H.A. Hjuler, J.O. Jensen (Eds.), High Temperature Polymer Electrolyte Membrane Fuel Cells: Approaches, Status and Perspectives, Springer, Switzerland (2016).

[2] G. Schuller et al., Journal of Power Sources, 347, 47 (2017).