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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Hydrogenation of Liquid Organic Hydrogen Carrier by electrochemical reduction

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire des technologies de valorisation des procédés et des matériaux pour les EnR

01-10-2021

SL-DRT-21-0471

vincent.faucheux@cea.fr

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

Hydrogen is expected to be the energy carrier of tomorrow due to the versatility of its ways of production and use. Nevertheless, its storage remains a major technological and scientific challenge. An alternative to the compression or liquefaction of H2 - energy-intensive and expensive processes - consists in storing and transporting hydrogen at atmospheric pressure and at ambient temperature (via existing infrastructures) using Liquid Organic Hydrogen Carrier (LOHC). These molecules can undergo reversible hydrogenation / dehydrogenation cycles in the presence of a catalyst. This technology therefore makes it possible to transport hydrogen from its production site (via electrolysis) to its site of use thanks to the these liquid molecules. A hindrance to the commercial deployment of this technology is in the energy efficiency of the whole process and the cost of the hydrogenation / dehydrogenation reactors. Indeed, hydrogenation / dehydrogenation reactions are highly exothermic / endothermic and require relatively high temperatures and efficient catalysts, often based on platinum group metal (PGM). In addition, the hydrogenation step requires the prior generation of H2 by electrolysis. The implementation of a direct hydrogenation of LOHC molecules at room temperature and pressure by electroreduction, would minimize the energy needs associated with this hydrogenation step, and would open the field of application of this LOHC technology.

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Predictive analysis, synthesis and validation of PGM free catalysts for a relevant decomposition of NH3 at lower temperature

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire des technologies de valorisation des procédés et des matériaux pour les EnR

01-10-2021

SL-DRT-21-0523

jerome.delmas@cea.fr

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

Hydrogen is expected to be the energy carrier of tomorrow due to the versatility of its ways of production and use. However, conventional storage solutions (under pressure, liquid H2,...) have some drawbacks (cost, energy requirement, losses by diffusion or boiling). In this context, different alternatives exist like ammonia. Ammonia has undeniable advantages for the storage of H2 with high energy densities (108 kg H2/m3 NH3 at 20°C-8.6bar; 17.8% wt H2) and existing infrastructure for its distribution. Furthermore, its use either as NH3 or as H2 after decomposition makes it possible to consider ammonia for multiple applications. Its decomposition is endothermal and a high temperature (> 700 ° C) is mandatory to ensure its decomposition with high kinetics. This temperature implies the aging of the catalysts and has a strong impact on the mechanical strength of the reactors with time. Developing catalysts allowing the efficient decomposition (kinetics, cost) of NH3 at lower temperature, based on theoretical and experimental approach, would open the field of application of NH3 technologies.

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Preparation characterization and modelling of electrospun gas diffusion layer for PEM fuel cell

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

Laboratoire Composants Pemfc

01-09-2021

SL-DRT-21-0892

frederic.fouda-onana@cea.fr

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

Several GDL specifications ( thickness, fibers diameter) could be modified by using electrospun as technique to prepare fibers. The influence of the microstructures properties on the gas/liquid management within the GDL is of utmost important topic for improving the output power of PEM fuel cell. It was reported that at least 50 % of gas transport losses were assigned to the GDL. This impact is even more severe at higher current density (> 3 A/cm²). At such regime the liquid water prevent the gas for reaching the catalyst and the voltage falls sharply. This phenomenon is known as ?flooding effect?. A better understanding of the relationship between macro properties/local properties/electrochemical performances will considerably improve ours insights on this technology. The scientific work will be based on two pillars: 1 - Preparation and characterizations (SEM, electron conductivity, Thermal and gas diffusion) of the electrospun carbon layer 2- Using already available (Matlab/Simulink) or Pores Network Modelling (PNM) tool to link local properties with effective transport properties. Then ijn a second step to connect the effectives transport properties of the GDL to PEM fuel performances model.

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