Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

Technological challenges >> Advanced hydrogen and fuel-cells solutions for energy transition
3 proposition(s).

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Investigation of manufacturing process related structure and performance of fuel cell electrode

Département de l'Electricité et de l'Hydrogène pour les Transports (LITEN)

Laboratoire Composants Pemfc

01-10-2020

SL-DRT-20-0365

arnaud.morin@cea.fr

Advanced hydrogen and fuel-cells solutions for energy transition (.pdf)

Zero emission automotive using hydrogen as a fuel and powered by a proton exchange membrane (PEM) fuel cell are now commercially available. However, large-scale commercialization of PEM fuel cell vehicles requires progress in performance, cost and durability, for which the electrode is the most limiting component. It is made of a random assembly of platinum based nanoparticles within a proton conducting polymer network. The electrode is obtained from a slurry after evaporating the solvents. Currently, research and development to improve the performance of the electrode and reduce the cost of manufacturing rely on a trial and error basis. The goal of this project is to increase the knowledge on the relationships between ink composition, electrode structure, properties and performance. The evolution of the ink during the drying process and the so obtained electrode will be characterized using neutron and X-Ray scattering, as complementary tools to unravel the organization of the catalyst material and of the polymer. By correlating these results with Operando electrochemical, structural and imaging measurements, we aim at rationalizing the design of the electrodes. This project involves partners having all the complementary skills needed for this study of most interest for the industrial partner, which is a leader in the research, development and production of fuel cell cars.

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Degradation Mechanisms of the Lanthanum Strontium Cobalt Ferrite Used as Oxygen Electrode in Solid Oxide Cells

Département Thermique Biomasse et Hydrogène (LITEN)

Laboratoire Production d'Hydrogène

01-10-2020

SL-DRT-20-0622

bertrand.morel@cea.fr

Advanced hydrogen and fuel-cells solutions for energy transition (.pdf)

Solid oxide cells (SOCs) are electrochemical devices operating at high temperature that can directly convert fuel into electricity (fuel cell mode ? SOFC) or electricity into fuel (electrolysis mode ? SOEC). In recent years, the interest on SOCs has grown significantly thanks to their wide range of technological applications that could offer innovative solutions for the transition toward a renewable energy market. Indeed, the SOCs present various advantages, such as a good reversibility, a large fuel flexibility and a very high efficiency. Despite these advantages, the degradation in performances is still too high to envisage the industrial deployment of this technology. Among the different degradation phenomena, the destabilization of the oxygen electrode, classically made of Lanthanum Strontium Cobalt Ferrite (LSCF), is recognized to contribute significantly to the cell ageing, especially when operated in electrolysis mode. In this context, the aim of the PhD thesis is to investigate the mechanisms controlling the electrode phase demixing and the diffusion of chemical elements. For this purpose, an experimental and modeling approach will be adopted including electrochemical testing and advanced post-test characterizations. Nano-imaging by synchrotron X-ray fluorescence and diffraction will be conducted on the aged electrodes. The acquired data will be implemented in an existing multiscale model to analyze the degradation mechanisms. Finally, recommendations in terms of materials and manufacturing conditions will proposed to improve the cell lifetime.

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Simulation of PEMFC manufacturing irregularities

Département de l'Electricité et de l'Hydrogène pour les Transports (LITEN)

Laboratoire Modélisation multi-échelle et suivi Performance

01-10-2020

SL-DRT-20-0799

pascal.schott@cea.fr

Advanced hydrogen and fuel-cells solutions for energy transition (.pdf)

The cost of PEMFC remains the bottleneck for moving the technology to the market place. Membrane electrode assembly (MEA) manufacturing must be cost-effective and assure high quality. In-line diagnostic tools have been developed by the NREL (National Renewable Energy Laboratory), that monitor the quality of electrode coatings. They have been successfully used to detect a variety of electrode coating irregularities in R2R (Roll-to-Roll) manufactured material sets. However, limited understanding exists regarding if and to what extent electrode irregularities impact PEMFC performance and lifetime. The objective of this PhD thesis, is to improve the understanding of and predict lifetime of MEA that contain material irregularities, such as for example membrane holes or cracks, and electrode voids or thick spots. CEA's multi-physics and multi-scale modeling approach will be used, coupled with a statistical analysis of experimental data provided by or collected at NREL. The following focus areas will be addressed: ? Impact of the defects (pinholes, catalyst degradation, non uniform distribution) on performance (potential mixt) ? Impact of the defects (particle size distribution, membrane thinning) on degradation ? Probabilistic failure prediction based on sensitivity analyses of mechanistic model and experimental data The thesis will be located at CEA Grenoble France, with several 3 months missions at NREL, Colorado, USA.

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