Degradation factors in (La,Sr)(Co,Fe)O3- cathode/Sm2O3–CeO2 interlayer/Y2O3–ZrO2 electrolyte system during operation of solid oxide fuel cells

Matsui, Toshiaki; Komoto, Masahiro; Muroyama, Hiroki; Kishida, Kyosuke; Inui, Haruyuki; Eguchi, Koichi

doi:10.1016/j.jpowsour.2016.02.052

Cited by 40 publications

(40 citation statements)

References 41 publications

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“…Note that the NTK cells have also porous GDC interlayers between the LSCF cathode and the YSZ electrolyte and exhibit slightly the SrZrO 3 formation and corresponding small conductivity lowering during several‐thousand‐hour operation. Those excellent behaviors of the present stacks contrasts with those results on the button cells or the single cell experiments which show rather fast formation of SrZrO 3 and severe damage in ohmic losses .…”

Section: Degradations Associated With Electrolytescontrasting

confidence: 99%

“… proposed that making DC films dense is effective. On the other hand, high temperature heat treatment is needed to sinter DC in dense films in a usual industrial method, and this promotes inevitably the interdiffusion between DC and YSZ , , resulting in decrease in ionic conductivity in the intermediate composition region . Furthermore, more complicated features have been clarified about the processing of the LSCF/DC/YSZ layers from the fundamental investigations on the mass transportation associated with the SrZrO 3 formation , , .…”

Section: Degradations Associated With Electrolytesmentioning

confidence: 99%

“…The stack degradation issues have been extracted from the stack performance tests made by CRIEPI on respective stacks with the same technique of separating measured voltage losses into several different contributions and their degradation rates and also by Tokyo Gas on thermal cycle characteristics . Degraded parts have been carefully examined by means of detailed analyses on changes in electrode microstructure with combined focussed ion beam scanning electron microscopy (FIB‐SEM) and 3D reconstruction technique by KyotoU, in deposited impurities at electrochemically active sites detected with secondary‐ion mass spectroscopy (SIMS) by AIST, with scanning transmission electron miscroscopy (STEM) by KyushuU and in electro‐chemo‐mechanical features by TohokuU. Such combined and systematic efforts in understanding degradations of SOFC stacks have revealed interesting general features of SOFCs as follows: Stack degradation behaviors are, in many cases, different from those in single or button cells.…”

Section: Introductionmentioning

confidence: 99%

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Achievements of NEDO Durability Projects on SOFC Stacks in the Light of Physicochemical Mechanisms

et al. 2019

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Achievements of NEDO durability projects on SOFC mode are summarized with a focus on the physicochemical mechanisms characterized by diffusion properties of cell components and chemical reactions of cell components with gaseous impurities. Ni sintering and depletion including impurity (P, B, S) effects have been examined in terms of the surface/interface energies of Ni/oxide cermet anodes. The conductivity degradation due to the transformation of the cubic YSZ electrolyte was found to be characterized in terms of two time constants for the reductive and the oxidative regions to be determined by the Y‐diffusivity and its enhancement on NiO internal reduction in YSZ, while observed gaps in conductivity degradation behavior between stacks and button cells were ascribed to differences in those physicochemical properties involved, namely cation diffusion and kinetics associated with NiO internal reduction. The cathode performance degradation due to sulfur poisoning exhibits a variety of dependences on the microstructure (dense or porous) of doped‐ceria interlayers, the thickness of YSZ electrolyte and the humidity in the anode atmosphere, suggesting effects of protons in the cathode vicinity and the SrO activity changes during fabrication the LSCF/GDC/YSZ multilayers. Some defect chemical considerations were made on how such defects are affected by fabrication processes.

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Section: Degradations Associated With Electrolytescontrasting

confidence: 99%

Section: Degradations Associated With Electrolytesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Achievements of NEDO Durability Projects on SOFC Stacks in the Light of Physicochemical Mechanisms

et al. 2019

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“…For SDC/YSZ bilayers, where the YSZ layer is deposited, using a pulsed laser deposition technique avoids the hightemperature ring step, and the interdi usion between the two layers has not been observed [21]. Additional studies report that the dissolution of Sm into the YSZ phase can also result in decreased ionic conductivity in the electrolyte [22,23].…”

Section: Discussion and Resultsmentioning

confidence: 99%

XPS Studies of LSCF Interfaces after Cell Testing

DiGiuseppe

Boddapati

Mothikhana

2018

Advances in Materials Science and Engineering

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e motivation of this investigation is to explore the possibility of using the depth profile capability of XPS to study interfaces after SOFC button cell testing. e literature uses XPS to study various cathode materials but has devoted little to the understanding of various cathode interfaces especially after testing. In this work, an SOFC button cell is first tested, and then, the LSCF cathode, barrier layer, and electrolyte are sputtered away to study the behavior of different interfaces. is work has shown that some elements have moved into other layers of the SOFC cell. It is argued that the migration of the elements is partly due to a redeposition mechanism after atoms are sputtered away, while the rest is due to interdiffusion between the SDC and YSZ layers. However, additional work is needed to better understand the mechanism by which atoms move around at different interfaces. e cell electrochemical performance is also discussed in some details but is not the focus.

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“…For SDC/YSZ bilayers where the SDC layer is deposited, using a Pulsed Laser Deposition technique avoids the high temperature firing step, and the interdiffusion between the two layers has not been observed [18]. Additional studies report that the dissolution of Sm into the YSZ phase can also result in decreased ionic conductivity in the electrolyte [19,20]. The reason that interdiffusion between SDC and YSZ layer is not observed in the tested cell is likely due to the low firing temperature of the SDC layer (1240 ∘ C).…”

Section: Resultsmentioning

confidence: 99%

Characterization of Solid Oxide Fuel Cells with LSCF-SDC Composite Cathodes

DiGiuseppe

Boddapati

2018

Journal of Energy

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This paper reports the study of an anode-supported SOFC cell containing an LSCF-SDC composite cathode. The SOFC cell was tested at different temperatures and reactant flow rates. After testing, the cell was sectioned and characterized using SEM/EDS. Such analysis indicated that no structural damage and no significant interdiffusion of elements among the layers occurred. The measured electrochemical performance data at different temperatures indicate an Arrhenius behavior or temperature activated processes. The low-porosity anode functional layer appears to be very sensitive to low hydrogen contents. The electrochemical performance is also affected by changing air flow rates.

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Degradation factors in (La,Sr)(Co,Fe)O3- cathode/Sm2O3–CeO2 interlayer/Y2O3–ZrO2 electrolyte system during operation of solid oxide fuel cells

Cited by 40 publications

References 41 publications

Achievements of NEDO Durability Projects on SOFC Stacks in the Light of Physicochemical Mechanisms

Achievements of NEDO Durability Projects on SOFC Stacks in the Light of Physicochemical Mechanisms

XPS Studies of LSCF Interfaces after Cell Testing

Characterization of Solid Oxide Fuel Cells with LSCF-SDC Composite Cathodes

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