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Nouvelle publication

Publié le 21 juin 2018
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21 juin 2018

Nouvelle publication cosignée par V. Tezyk et E. Siebert "Experimental validation of a La0.6Sr0.4Co0.2Fe0.8O3-δ electrode model operated in electrolysis mode: Understanding the reaction pathway under anodic polarization" https://doi.org/10.1016/j.ssi.2018.02.012

Experimental validation of a La0.6Sr0.4Co0.2Fe0.8O3-δ electrode model operated in electrolysis mode: Understanding the reaction pathway under anodic polarization
F. Monacoa, V. Tezyk, E. Siebert, S. Pylypko, B. Morel, J. Vulliet, T. Le Bihan, F. Lefebvre-Joud, J. Laurencin
Solid State Ionics 319 (2019) 234-246

In order to validate the reaction mechanism of porous LSCF oxygen electrodes, a set of experiments has been
conducted on two types of symmetrical cells exhibiting different microstructures. In both cases, the polarization
curves exhibit a dissymmetry with a transition at low anodic overpotential associated to a modification in the
shape of the electrochemical impedance spectra. To interpret the experimental results, a micro-scale electrode
model including two reaction pathways has been used. The model considers an oxidation/reduction at TPBs
(surface path) in parallel to an oxygen transfer at the gas/LSCF interface (bulk path). Thanks to a 3D electrode
reconstruction, the simulations have been performed with a reduced number of unknown parameters. It has been
found that the simulated data are in good agreement with the experimental polarization curves and impedance
spectra at OCP as well as under anodic polarization. Once validated, the model has been used to unravel the
complex electrode operating mechanisms in electrolysis mode. The simulations have shown that the transition
detected at low anodic polarization is due to a change in the dominant reaction mechanism passing from the bulk
to the surface path. Moreover, the relative contribution of the two pathways has been investigated as a function
of temperature.
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Rédigé par Thierry Pagnier

mise à jour le 21 juin 2018

Communauté Université Grenoble Alpes