Scheelite-type materials such as LaNbO4 are increasingly attracting attention as a possible alternative to the most common fluorite and perovskite structure as ion conductors. However, they are much less used and investigated. The introduction of tungsten in lanthanum orthoniobate leads to conduction properties that are compatible with oxygen ion conductivity. In this paper, we studied the effect of the introduction of tungsten in the LaNbO4 structure. High resolution X-ray diffraction showed that in LaNb1-xWxO4+x/2 with x = 0.16 the monoclinic distortion is largely suppressed and the tetragonal phase is predominant at room temperature. By XANES/EXAFS we proved that tungsten is in its 6+ valence state and no W5+ was detected. With X-ray microspectroscopy, we studied in detail with a submicrometre-probe the interdiffusion and degradation processes taking place between the material and LSM, a common electrode material, during their long-term contact at high temperatures.
Canu G., Giannici F., Chiara A., Confalonieri G., Longo A., Buscaglia M.T., et al. (2020). Characterisation of scheelite LaW0.16Nb0.84O4.08 ion conductor by combined synchrotron techniques: Structure, W oxidation state and interdiffusion. JOURNAL OF ALLOYS AND COMPOUNDS [10.1016/j.jallcom.2020.157532].
Characterisation of scheelite LaW0.16Nb0.84O4.08 ion conductor by combined synchrotron techniques: Structure, W oxidation state and interdiffusion
Giannici F.;Martorana A.
2020-01-01
Abstract
Scheelite-type materials such as LaNbO4 are increasingly attracting attention as a possible alternative to the most common fluorite and perovskite structure as ion conductors. However, they are much less used and investigated. The introduction of tungsten in lanthanum orthoniobate leads to conduction properties that are compatible with oxygen ion conductivity. In this paper, we studied the effect of the introduction of tungsten in the LaNbO4 structure. High resolution X-ray diffraction showed that in LaNb1-xWxO4+x/2 with x = 0.16 the monoclinic distortion is largely suppressed and the tetragonal phase is predominant at room temperature. By XANES/EXAFS we proved that tungsten is in its 6+ valence state and no W5+ was detected. With X-ray microspectroscopy, we studied in detail with a submicrometre-probe the interdiffusion and degradation processes taking place between the material and LSM, a common electrode material, during their long-term contact at high temperatures.File | Dimensione | Formato | |
---|---|---|---|
pagination_JALCOM_157532.pdf
Solo gestori archvio
Descrizione: articolo
Tipologia:
Post-print
Dimensione
1.12 MB
Formato
Adobe PDF
|
1.12 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
pre print giannici.pdf
accesso aperto
Descrizione: articolo
Tipologia:
Pre-print
Dimensione
6.48 MB
Formato
Adobe PDF
|
6.48 MB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.