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MM: Fachverband Metall- und Materialphysik

MM 5: Materials in Energy Conversion: Mechanical Properties and Solid State Batteries

MM 5.10: Talk

Monday, March 27, 2023, 12:45–13:00, SCH A 215

Active Site Deactivation of the Air Electrode in High-Temperature Solid Oxide Cells — •Hanna Türk, Thomas Götsch, Franz-Philipp Schmidt, Axel Knop-Gericke, Robert Schlögl, Thomas Lunkenbein, Karsten Reuter, and Christoph Scheurer — Fritz-Haber-Institut der MPG, Berlin, Germany

Degradation of the air electrode in electrolysis mode severely limits the commercial adoption of solid oxide cells (SOCs). This degradation goes hand in hand with the oxygen evolution reaction (OER) taking place at the triple-phase boundary (TPB) between the anode, the solid electrolyte, and the gas phase. Up to now, the atomistic structure of this active catalyst region is essentially unknown, though, which prevents a detailed analysis of the actual degradation mechanisms.

Recently, we took the first step in elucidating the TPB structure by revealing a complexion at the underlying solid/solid interface of the sintered anode[1], featuring partial amorphization and varying elemental distributions deviating from the confining bulk phases. Based on this finding, we now expand our force field based Monte-Carlo simulations to the OER active site. Our experimentally validated results show unexpected compositional changes with respect to the thermodynamic equilibrium, that combined with a spatially resolved diffusion study indicate a hitherto unknown mechanism underlying the deactivation of the anode[2].

[1] H. Türk et al., Adv. Mater. Interfaces 8, 2100967 (2021).

[2] H. Türk et al., ChemCatChem 14, e202200300 (2022).