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Accueil du site > Jobs - PostDoc - These > Post-doctoral position available at CEA - Bruyeres-le-Chatel

Post-doctoral position available at CEA - Bruyeres-le-Chatel

par Nord & Ile de France - 10 septembre

Post-doctoral proposal : Multi-scale Modeling of High Temperature Solid Oxide Cells

Context and issues :

Ceramic high-temperature fuel cells and electrolysers are efficient energy-conversion systems for electrical power generation and hydrogen production. Thanks to their high flexibility in terms of technological applications, the same device can be alternatively used in fuel cell and steam electrolysis modes. This type of high-temperature electrolyser-fuel-cell device is constituted by a stack of elementary Solid Oxide Cells (SOCs), each one being composed of a dense electrolyte sandwiched between two porous electrodes. In this device, the electrodes are key components regarding the global system efficiency and durability. The H2 electrode is classically made of Nickel and Yttria Stabilized Zirconia (Ni-YSZ), while the O2 electrode is made of Lanthanum Strontium Cobalt Ferrite (LSCF). Nevertheless, despite this crucial importance, the fundamental elementary reaction pathways for both electrodes are not precisely understood. To clarify these issues, refinements in the elementary kinetic models are still required.

Objectives and work plan :

The candidate will use ab initio simulations to model the interaction between O2 and the surface of LSCF, as well as the electronic and ionic transport in the bulk of LSCF. In this compound, the electronic conduction is based on the small polaron hopping mechanism, that will be carefully treated using DFT+U [1]. The results of the computation conducted at the atomic scale will be then analyzed in order to identify relevant reaction pathways for the global electrode. The proposed mechanism associated with its activation energies will be implemented in an existing kinetic model developed at the scale of the complete electrode [2,3]. The upgraded macroscopic model will be used to simulate the electrode polarization curves and electrochemical impedance spectra. The simulations will be finally confronted to experimental characterizations in order to validate the multi-scale modeling. The ab initio calculations will be performed with the ABINIT code [4] and will use the capabilities of the CEA supercomputers.

The candidate must have a PhD in solid-state physics or solid-state chemistry, and a strong experience with modeling and numerical simulations.

Period : 12 months (with a possible extension to 2 years).

Location : Bruyères-le-Châtel CEA center.

Supervisors : G. Geneste (CEA/DAM) and J. Laurencin (CEA/LITEN) :

Contact : gregory.geneste@cea.fr and jerome.laurencin@cea.fr

[1] G. Geneste, B. Amadon, M. Torrent, G. Dezanneau, Phys. Rev. B 96, 134123 (2017).

[2] J. Laurencin et al, Electrochimica Acta 174, 1299 (2015).

[3] F. Monaco et al, Solid State Ionics 319 (2018) 234-246.

[4] X. Gonze et al, Comput. Phys. Comm. 205, 106 (2016).