BRIDGE

BRIDging the environment(al) Gap: promising catalyst materials to performant fuel cells Electrodes

The present project proposal aims at identifying and unlocking obstacles limiting the implementation of promising ORR catalyst materials, identified after fundamental and model investigations in well-controlled laboratory conditions, into efficient PEMFC cathodes. To this goal, a library of materials composed of state-of-the-art ORR nanocatalysts (octahedral, cubic, hollow, nanowires and spongy) will be built, and the synthesis processes will be scaled-up in a stepwise manner to reach volumetric quantities allowing MEAs manufacturing.
 

Figure 1. Example of preferentially shaped carbon-supported or unsupported PtNi/C NPs recently synthesized at LEPMI. (a-c, e-g) STEM/X-EDS elemental maps of some nanostructures investigated in this study, high resolution TEM images with corresponding fast Fourier transform of (d) cube Pt/C and (h) hollow PtNi/C NPs.

The (i) structure and the chemistry of these nanocatalysts and (ii) the ionomer content and distribution within the cathode structure will be determined at each step of the membrane-electrodes assembly (MEA) manufacturing to rationalize changes of performance in model and real PEMFC systems. A specific diagnostic toolbox, combining advanced experimental techniques and modelling, will be specifically developed and the output of this toolbox will be used to adapt the ink formulation from which the MEAs are manufactured (catalyst content and chemistry, ionomer content and chemistry, solvent composition, use of additives). Strategies to mitigate issues related to low density of catalytic sites (highly-active ORR nanocatalysts usually feature large crystallite size), incomplete wetting of the catalyst by the ionomer and poor accessibility for oxygen to the catalytic sites will be also developed. Finally, accelerated stress tests (ASTs) will be carried out. After characterisation, the results of these tests will help rationalizing why the degradation mechanisms may be different in simulated and real PEMFC operating conditions. Ultimately, the key findings of the project will be transferred to Heraeus and Symbio for industrial development.

The BRIDGE project brings together two groups at LEPMI and ZSW (Zentrum für Sonnenenergie- und Wasserstoff-Forschung), and two industrial partners Heraeus and Symbio. LEPMI will use its expertise in the synthesis of ORR nanocatalysts and electrocatalysis using model electrodes to understand the structural, compositional and morphological changes occurring during elaboration of MEAs, while the ZSW group will engineer them to implement them in real-life PEMFC. The two industrial partners, Heraeus and Symbio, are a well-established catalyst materials manufacturer and an automotive equipment supplier designing and developing a large range of PEMFC related products, from specifically designed MEAs to a few hundred kW systems, for electric vehicles, respectively. The BRIDGE project thus covers all the facets of a critical technology that is expected to grow further for the development of independent European-based solutions in the field of sustainable energy transition.
 

Acknowledgements

This work is performed within the framework of the Centre of Excellence of Multifunctional Architectured Materials "CEMAM" n° AN-10-LABX-44-01 funded by the "Investments for the Future" program. The authors acknowledge financial support from the French National Research Agency through the BRIDGE project.

References

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