Transition Metal Spinel Oxide Coatings for Reducing Chromium Poisoning in SOFCs

Fergus, Jeffrey W.; Wang, Kangli; Liu, Yingjia

doi:10.1149/1.3589187

Cited by 7 publications

(4 citation statements)

References 17 publications

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“…Similar reductions in the Cr-rich layer thickness have been observed in other substituted manganese cobalt oxides with lower doping content (≤ 11%). 20,29 Figure 5b shows the Fe dopant concentration profile after hightemperature reaction. Fe was not observed in the Cr-rich outer reaction layer in the MnCo 2-x Fe x O 4 spinel oxides according to EDS analysis.…”

Section: Resultsmentioning

confidence: 99%

Crystal Structure, Chemical Stabilities and Electrical Conductivity of Fe-Doped Manganese Cobalt Spinel Oxides for SOFC Interconnect Coatings

Liu

Fergus

Wang

2013

J. Electrochem. Soc.

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The application of ceramic coatings has been demonstrated as an effective technique to suppress the oxidation scale growth and chromium volatilization of ferritic stainless steels used for SOFC interconnects. Manganese cobalt spinel oxides are promising materials for this application. In this work, the effects of iron doping in the MnCo2-xFexO4 (x = 0–0.7) spinel oxide on the crystal structure, reaction with chromia, cation distributions, and electrical conductivity at high temperature were investigated. With increasing the iron content, the lattice parameters increase and the electrical conductivity decreases. During reaction with chromia, iron does not appear in the chromium-rich reaction layer even for the sample with heaviest doping (e.g. MnCo1.3Fe0.7O4). Neutron diffraction studies suggest that cobalt has a stronger preference for the tetrahedral sites while manganese and iron favor the octahedral sites.

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Section: Resultsmentioning

confidence: 99%

Crystal Structure, Chemical Stabilities and Electrical Conductivity of Fe-Doped Manganese Cobalt Spinel Oxides for SOFC Interconnect Coatings

Liu

Fergus

Wang

2013

J. Electrochem. Soc.

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“…Currently, many studies are focusing on the possibility to improve the (Mn,Co)3O4 spinel further by transition metal doping, in particularly with Fe or/and Cu [44,[47][48][49][50][51][52][53][54][55]. Since the coating properties are strongly affected by the preparation procedure, there is considerable scatter in the literature results.…”

Section: Introductionmentioning

confidence: 99%

Electrophoretic co-deposition of Fe2O3 and Mn1,5Co1,5O4: Processing and oxidation performance of Fe-doped Mn-Co coatings for solid oxide cell interconnects

Zanchi

Talic

Sabato

et al. 2019

Journal of the European Ceramic Society

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“…Hence, the ASR is derived from the measured voltage drop with the assumption that the contribution to the ohmic losses at the steel/coating interface is at least one order of magnitude higher than at the other contact interfaces and through the LSC paste. For instance, at 700 • C, the electrical resistivity of chromia lies in the range 10-10 3 cm, 14 which is several orders of magnitude higher than that reported for the LSC cathode. 15 Besides, the method has been previously validated with a commercial Ce/Co coated Sandvik Sanergy HT steel used as benchmark: 13 a very low contact cell unit resistance (ca.…”

Section: Methodsmentioning

confidence: 64%

Composite Cu-LaFeO₃Conversion Coatings on a 18Cr Ferritic Stainless Steel for IT-SOFC Interconnects: Effect of Long-Term Air Exposure at 700°C on Cr Diffusion Barrier and Electrical Properties

Frangini

Masi

Seta

et al. 2018

J. Electrochem. Soc.

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In our previous study copper oxide additions were used to accelerate the formation of perovskite LaFeO 3 conversion coatings on stainless steels from molten carbonate baths. Incorporation of copper particles into the growing coating was an additional effect resulting in the formation of a composite Cu-LaFeO 3 structure. In continuation to our previous study, the aim of this work is to report the effect of copper additions on long-term stability and performance of perovskite conversion coatings under IT-SOFC interconnect conditions. To this end, a Cu-LaFeO 3 coated K41 18Cr ferritic stainless steel was examined in air at 700 • C up to 1000 h. In order to simulate properly the situation of a real IT-SOFC cell, Area Specific Resistance (ASR) and Cr-barrier properties of the coated steel were evaluated simultaneously with a special coating characterization setup. Studies were conducted by comparison with single-phase LaFeO 3 coatings obtained in a molten carbonate bath similar to that used for the formation of the composite Cu-LaFeO 3 coatings but without the addition of copper oxide. Copper addition did not change the general morphology of the perovskite coating, which remains a multi-layer coating, being composed of an outer LaFeO 3 crystalline layer, a middle Fe-rich oxide and two inner Fe-Cr rich oxide layers. However, copper was beneficial in promoting a thinner and more stable coating structure along with finer perovskite grain size. These structural improvements were further confirmed by the results obtained with electrical measurements that showed a better ASR behavior of the Cu-LaFeO 3 coatings. On the other hand, no relevant copper effects could be detected on the coating oxidation stability and on the Cr-barrier properties of the perovskite conversion coatings. Both LaFeO 3 and Cu-LaFeO 3 coatings showed similarly high coating stability and excellent Cr-barrier capability in experiments conducted at 700 • C up to 1000 h. In definitive, dual-phase Cu-LaFeO 3 seem more promising systems for IT-SOFC interconnects than single-phase LaFeO 3 conversion coatings, although further improvements in ASR electrical properties are needed. Conventional 18Cr ferritic stainless steels are promising candidates for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC) interconnects as they provide an optimal combination of cost, structural and chemical composition properties.1-3 However, the use of 18Cr ferritic stainless steels is not without its cost. Issues are related to formation of insulating chromia layers with high tendency to evaporate during their exposure to the IT-SOFC operating conditions. Hence, coating with a ceramic layer made of electro-conductive and corrosion-resistant spinel 4 or perovskite 5 oxides is usually considered a necessary addition for ensuring a stable and low Area Specific Resistance (ASR), which is a common way to express interfacial ohmic resistance in electrochemical devices. In particular, (Co-Mn) or (CuMn)-based spinel oxides as well as (La-Cr), (La-Co) or (La-Mn) perovskite oxides h...

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Transition Metal Spinel Oxide Coatings for Reducing Chromium Poisoning in SOFCs

Cited by 7 publications

References 17 publications

Crystal Structure, Chemical Stabilities and Electrical Conductivity of Fe-Doped Manganese Cobalt Spinel Oxides for SOFC Interconnect Coatings

Crystal Structure, Chemical Stabilities and Electrical Conductivity of Fe-Doped Manganese Cobalt Spinel Oxides for SOFC Interconnect Coatings

Electrophoretic co-deposition of Fe2O3 and Mn1,5Co1,5O4: Processing and oxidation performance of Fe-doped Mn-Co coatings for solid oxide cell interconnects

Composite Cu-LaFeO₃Conversion Coatings on a 18Cr Ferritic Stainless Steel for IT-SOFC Interconnects: Effect of Long-Term Air Exposure at 700°C on Cr Diffusion Barrier and Electrical Properties

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Transition Metal Spinel Oxide Coatings for Reducing Chromium Poisoning in SOFCs

Cited by 7 publications

References 17 publications

Crystal Structure, Chemical Stabilities and Electrical Conductivity of Fe-Doped Manganese Cobalt Spinel Oxides for SOFC Interconnect Coatings

Crystal Structure, Chemical Stabilities and Electrical Conductivity of Fe-Doped Manganese Cobalt Spinel Oxides for SOFC Interconnect Coatings

Electrophoretic co-deposition of Fe2O3 and Mn1,5Co1,5O4: Processing and oxidation performance of Fe-doped Mn-Co coatings for solid oxide cell interconnects

Composite Cu-LaFeO3Conversion Coatings on a 18Cr Ferritic Stainless Steel for IT-SOFC Interconnects: Effect of Long-Term Air Exposure at 700°C on Cr Diffusion Barrier and Electrical Properties

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Composite Cu-LaFeO₃Conversion Coatings on a 18Cr Ferritic Stainless Steel for IT-SOFC Interconnects: Effect of Long-Term Air Exposure at 700°C on Cr Diffusion Barrier and Electrical Properties