TOWARDS THE OPERANDO ANALYSIS OF SOFC DEVICES IN ENVIRONMENTAL TRANSMISSION ELECTRON MICROSCOPY - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2023

TOWARDS THE OPERANDO ANALYSIS OF SOFC DEVICES IN ENVIRONMENTAL TRANSMISSION ELECTRON MICROSCOPY

Q. Jeangros
  • Fonction : Auteur
M. Bugnet
  • Fonction : Orateur
C. Frantz
  • Fonction : Auteur
S. Diethelm
  • Fonction : Auteur
E. Tyukalova
  • Fonction : Auteur
Y. Pivak
  • Fonction : Auteur
J. Van-Herle
  • Fonction : Auteur
A. Hessler-Wyser
  • Fonction : Auteur
M. Duchamp
  • Fonction : Auteur

Résumé

Solid oxide fuel cells (SOFC) are a class of solid-state electrochemical conversion devices that produce electricity directly by oxidizing a fuel gas. They consist in an anode-cathode duet separated by a solid electrolyte conducting oxygen ions. The anode is fed with hydrogen or other fuels whereas the cathode is in contact with air. Overall, a SOFC operates from the combined action of two external stimuli: a gaseous environment and temperature. Owing to recent advances of in situ and operando transmission electron microscopy, we set up an experiment to operate a SOFC inside an environmental TEM (ETEM) to identify how the device microstructure determines its electrical properties [1]. An elementary anode(NiO)–electrolyte(yttria-stabilized zirconia)–cathode(Sr-doped lanthanum manganite) sandwich was prepared by focused ion beam and mounted on a heating/biasing MEMS-based specimen holder (DENSsolutions, Fig. 1) and inserted in a dedicated ETEM (FEI Titan). Due to the difference in catalytic activity between the electrodes, O2 should reduce at the cathode, while H2 should oxidize at the anode, thus leading to a voltage difference. The reduction of NiO was first performed under a forming gas N2:H2 (ratio 20:1) under 15 mbar up to 750°C. The O2 to H2 ratio was then increased to trigger the SOFC operation, leading to a total pressure of 16 mbar at 600°C. At this point, the variation of voltage between the anode and cathode was correlated to gas composition and anode microstructure (Fig. 2). The latter was analyzed by means of conventional and high-resolution imaging, diffraction, and EELS. The system was cycled several times by decreasing and re-increasing the O2 concentration in the gas flow, and correlations between microstructure, gas composition, and SOFC voltage were established. Results were further confirmed by macroscopic ex situ tests. Such operando experiments open numerous perspectives to investigate the root cause of failure pathways affecting SOFCs, like poisoning of active sites or coarsening of the Ni catalyst [2]. Références/References : [1] Q. Jeangros et al., under review; arXiv https://doi.org/10.48550/arXiv.2302.12514. [2] The authors acknowledge the METSA network, the France-Singapore MERLION program (INSTANT project), and the start-up grant M4081924 at NTU
Fichier non déposé

Dates et versions

hal-04229752 , version 1 (05-10-2023)

Identifiants

  • HAL Id : hal-04229752 , version 1

Citer

Q. Jeangros, M. Bugnet, T. Epicier, C. Frantz, S. Diethelm, et al.. TOWARDS THE OPERANDO ANALYSIS OF SOFC DEVICES IN ENVIRONMENTAL TRANSMISSION ELECTRON MICROSCOPY. 18ème Colloque de la SFµ, Jul 2023, Rouen, France. ⟨hal-04229752⟩
11 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More