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Analysis of Performance Losses and Degradation Mechanism in Porous La2-X NiTiO66-Ç:YSZ Electrodes

Título : Analysis of Performance Losses and Degradation Mechanism in Porous La2-X NiTiO66-Ç:YSZ Electrodes
Autor : Pérez Flores, Juan Carlos
Castro García, Miguel
Crespo Muñoz, Vidal
Valera Jiménez, José Fernando
García Alvarado, Flaviano
Canales Vázquez, Jesús
Materias: SOFCCathodeDegradationPerovskiteLong-termEx-solution
Editorial : MDPI
Citación : Pérez-Flores, J.C.; Castro-García, M.; Crespo-Muñoz, V.; Valera-Jiménez, J.F.; García-Alvarado, F.; Canales-Vázquez, J. Analysis of Performance Losses and Degradation Mechanism in Porous La2􀀀X NiTiO6􀀀 :YSZ Electrodes. Materials 2021, 14, 2819. https://doi.org/ 10.3390/ma14112819
Resumen : The electrode performance and degradation of 1:1 La2-xNiTiO6-ç:YSZ composites (x = 0, 0.2) has been investigated to evaluate their potential use as SOFC cathode materials by combining electrochemical impedance spectroscopy in symmetrical cell configuration under ambient air at 1173 K, XRD, electron microscopy and image processing studies. The polarisation resistance values increase notably, i.e., 0.035 and 0.058 Wcm2 h-1 for x = 0 and 0.2 samples, respectively, after 300 h under these demanding conditions. Comparing the XRD patterns of the initial samples and after long-term exposure to high temperature, the perovskite structure is retained, although La2Zr2O7 and NiO appear as secondary phases accompanied by peak broadening, suggesting amorphization or reduction of the crystalline domains. SEM and TEM studies confirm the ex-solution of NiO with time in both phases and also prove these phases are prone to disorder. From these results, degradation in La2-xNiTiO6-ç:YSZ electrodes is due to the formation of La2Zr2O7 at the electrode–electrolyte interface and the ex-solution of NiO, which in turn results in the progressive structural amorphization of La18NiTiO6-ç phases. Both secondary phases constitute a non-conductive physical barrier that would hinder the ionic diffusion at the La2-xNiTiO6-ç:YSZ interface and oxygen access to surface active area.
URI : http://hdl.handle.net/10637/14740
Derechos: http://creativecommons.org/licenses/by-nc-nd/4.0/deed.es
OpenAccess
ISSN : 1996-1944
Fecha de publicación : 25-may-2021
Centro : Universidad San Pablo-CEU
Aparece en las colecciones: Facultad de Farmacia





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