Solid-state compatibility of Ca:LaNbO4 with perovskite cathodes: Evidences from X-ray microspectroscopy
- Autori: Chiara A.; Canu G.; Longo A.; Pipitone C.; Martorana A.; Giannici F.
- Anno di pubblicazione: 2022
- Tipologia: Articolo in rivista
- OA Link: http://hdl.handle.net/10447/536995
Abstract
The solid-state compatibility between calcium-doped lanthanum niobate and three perovskite cathode materials was investigated using two X-ray microbeam techniques, micro X-ray fluorescence and micro X-ray absorption spectroscopy. The cathode powders (lanthanum strontium ferrite, either cobalt or copper-doped, and lanthanum strontium cobaltite) in contact with the dense electrolyte pellet were annealed at 1150°C for 12–144 h to simulate the effect of thermal stresses due to fabrication and long-term operation. As a result, several interdiffusion phenomena were then observed on the bilayer cross-sections: in particular, the chemical state and coordination environment of calcium, iron, niobium and lanthanum were probed with space-resolved X-ray absorption spectroscopy. The ab initio modeling of the near-edge X-ray absorption spectra reveal that the cation interdiffusion is facilitated by the structural flexibility of the perovskite structure, which is able to accommodate a variety of foreign cations in different oxidation states. Limited stability at high-temperatures was found for all candidate perovskite compositions in contact with lanthanum niobate.