Correlating surface crystal orientation and gas rinetics in perovskite oxide electrodes
Gao, Ran (University of California, Berkeley. Department of Materials Science and Engineering)
Fernandez, Abel (University of California, Berkeley. Department of Materials Science and Engineering)
Chakraborty, Tanmoy (University of Illinois at Urbana−Champaign. Beckman Institute for Advanced Science and TechnologyMaterials Sciences Division)
Luo, Aileen (University of California, Berkeley. Department of Materials Science and Engineering)
Pesquera, David (Institut Català de Nanociència i Nanotecnologia)
Das, Sujit (Lawrence Berkeley National Laboratory. Materials Sciences Division)
Velarde, Gabriel (University of California, Berkeley. Department of Materials Science and Engineering)
Thoréton, Vincent (Kyushu University. WPI International Institute for Carbon-Neutral Energy Research)
Kilner, John (Imperial College London. Department of Materials)
Ishihara, Tatsumi (Kyushu University. WPI International Institute for Carbon-Neutral Energy Research)
Nemšák, Slamovír (Lawrence Berkeley National Laboratory. Advanced Light Source)
Crumlin, Ethan J. (Lawrence Berkeley National Laboratory. Advanced Light Source)
Ertekin, E. (Department of Mechanical Science and Engineering. University of Illinois. Urbana-Champaign)
Martin, Lane W. (Lawrence Berkeley National Laboratory. Materials Sciences Division)

Data:	2021
Resum:	Solid-gas interactions at electrode surfaces determine the efficiency of solid-oxide fuel cells and electrolyzers. Here, the correlation between surface-gas kinetics and the crystal orientation of perovskite electrodes is studied in the model system LaSrCoFeO. The gas-exchange kinetics are characterized by synthesizing epitaxial half-cell geometries where three single-variant surfaces are produced [i. e. , LaSrCoFeO/LaSrGaMgO/SrRuO/SrTiO (001), (110), and (111)]. Electrochemical impedance spectroscopy and electrical conductivity relaxation measurements reveal a strong surface-orientation dependency of the gas-exchange kinetics, wherein (111)-oriented surfaces exhibit an activity >3-times higher as compared to (001)-oriented surfaces. Oxygen partial pressure ((Formula presented. ))-dependent electrochemical impedance spectroscopy studies reveal that while the three surfaces have different gas-exchange kinetics, the reaction mechanisms and rate-limiting steps are the same (i. e. , charge-transfer to the diatomic oxygen species). First-principles calculations suggest that the formation energy of vacancies and adsorption at the various surfaces is different and influenced by the surface polarity. Finally, synchrotron-based, ambient-pressure X-ray spectroscopies reveal distinct electronic changes and surface chemistry among the different surface orientations. Taken together, thin-film epitaxy provides an efficient approach to control and understand the electrode reactivity ultimately demonstrating that the (111)-surface exhibits a high density of active surface sites which leads to higher activity.
Ajuts:	European Commission 797123
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió sotmesa a revisió
Matèria:	Electrochemical reactions ; Epitaxial thin films ; Half-cells ; Perovskite oxides ; Surface engineering
Publicat a:	Advanced materials, Vol. 33, issue 10 (May 2021) , art. 2100977, ISSN 1521-4095

DOI: 10.1002/adma.202100977

Preprint 52 p, 3.8 MB

Postprint 51 p, 3.6 MB

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