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11 pages, 4061 KiB

Open AccessArticle

Manganese–Cobalt Based Spinel Coatings Processed by Electrophoretic Deposition Method: The Influence of Sintering on Degradation Issues of Solid Oxide Cell Oxygen Electrodes at 750 °C

by Elisa Zanchi, Justyna Ignaczak, Bartosz Kamecki, Piotr Jasiński, Sebastian Molin, Aldo R. Boccaccini and Federico Smeacetto

Materials 2021, 14(14), 3836; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14143836 - 09 Jul 2021

Cited by 12 | Viewed by 2371

Abstract

This paper seeks to examine how the Mn–Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn–Co spinel coating is processed on Crofer 22 APU [...] Read more.

This paper seeks to examine how the Mn–Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn–Co spinel coating is processed on Crofer 22 APU substrates by electrophoretic deposition, and subsequently sintered, following both the one-step and two-step sintering, in order to obtain significantly different densification levels. The electrochemical characterization is performed on anode-supported cells with an LSCF cathode. The cells were aged prior to the electrochemical characterization in contact with the spinel-coated Crofer 22 APU at 750 °C for 250 h. Current–voltage and impedance spectra of the cells were measured after the exposure with the interconnect. Post-mortem analysis of the interconnect and the cell was carried out, in order to assess the Cr retention capability of coatings with different microstructures. Full article

(This article belongs to the Special Issue Performance and Degradation Mechanisms of Electrode Materials for Solid Oxide Cells Devices)

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18 pages, 3036 KiB

Open AccessArticle

Analysis of Performance Losses and Degradation Mechanism in Porous La_2−X NiTiO₆₋_δ:YSZ Electrodes

by Juan Carlos Pérez-Flores, Miguel Castro-García, Vidal Crespo-Muñoz, José Fernando Valera-Jiménez, Flaviano García-Alvarado and Jesús Canales-Vázquez

Materials 2021, 14(11), 2819; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14112819 - 25 May 2021

Cited by 3 | Viewed by 1864

Abstract

The electrode performance and degradation of 1:1 La_2−xNiTiO₆₋_δ: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 [...] Read more.

The electrode performance and degradation of 1:1 La_2−xNiTiO₆₋_δ: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 Ωcm² 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 La_2−xNiTiO₆₋_δ: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₋_δ phases. Both secondary phases constitute a non-conductive physical barrier that would hinder the ionic diffusion at the La_2−xNiTiO₆₋_δ:YSZ interface and oxygen access to surface active area. Full article

(This article belongs to the Special Issue Performance and Degradation Mechanisms of Electrode Materials for Solid Oxide Cells Devices)

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Review

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25 pages, 29952 KiB

Open AccessReview

Degradation Mechanisms of Metal-Supported Solid Oxide Cells and Countermeasures: A Review

by Zhipeng Zhou, Venkata Karthik Nadimpalli, David Bue Pedersen and Vincenzo Esposito

Materials 2021, 14(11), 3139; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14113139 - 07 Jun 2021

Cited by 17 | Viewed by 5299

Abstract

Metal-supported oxide cells (MSCs) are considered as the third-generation solid oxide cells (SOCs) succeeding electrolyte-supported (first generation) and anode-supported (second generation) cells, which have gained much attention and progress in the past decade. The use of metal supports and advanced technical methods (such [...] Read more.

Metal-supported oxide cells (MSCs) are considered as the third-generation solid oxide cells (SOCs) succeeding electrolyte-supported (first generation) and anode-supported (second generation) cells, which have gained much attention and progress in the past decade. The use of metal supports and advanced technical methods (such as infiltrated electrodes) has vastly improved cell performance, especially with its rapid startup ability and power density, showing a significant decrease in raw materials cost. However, new degradation mechanisms appeared, limiting the further improvement of the performance and lifetime. This review encapsulates the degradation mechanisms and countermeasures in the field of MSCs, reviewing the challenges and recommendations for future development. Full article

(This article belongs to the Special Issue Performance and Degradation Mechanisms of Electrode Materials for Solid Oxide Cells Devices)

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