Stability and performance of La0.6Sr0.4Co0.2Fe0.8O3-δ nanostructured cathodes with Ce0.8Gd0.2O1.9 surface coating

Santos‐Gómez, Lucía dos; Porras-Vázquez, José M.; Losilla, Enrique R.; Martı́n, Francisco; Ramos-Barrado, J.R.; Marrero-López, D.

doi:10.1016/j.jpowsour.2017.02.045

Cited by 39 publications

(20 citation statements)

References 43 publications

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“…6a), a remarkable R p increase (from 0.8 · cm 2 to 1.03 · cm 2 ) is visible already in the first 72 hours of working time, showing a 29% performance degradation, in accordance with that reported in literature. 12,14,16,88,89 Conversely, the polarization resistance related to the LSM-infiltrated LSCF electrode decreases over time from 0.7 · cm 2 to 0.515 · cm 2 (26% decrease) in 220 hours (continuous spectra in Fig. 6a), confirming a positive effect of the LSM infiltration on the long-term stability of the LSCF electrode.…”

Section: Tga and Tpr Results-inmentioning

confidence: 78%

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δversus Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ

Giuliano

Carpanese

Clematis

et al. 2017

J. Electrochem. Soc.

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The two half-cell systems were compared to evaluate the influence of infiltration, overpotential and ageing on their performance and stability. Structure, microstructure and chemical composition were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with Energy Dispersive X-ray spectroscopy (EDX), whereas redox behavior was evaluated through temperature programmed reduction (TPR) and thermal gravimetric analysis (TGA) in combination with electrochemical impedance spectroscopy (EIS), which was also used to test the electrochemical performance. A decrease of polarization resistance for both infiltrated electrodes, compared to the reference ones, was highlighted at open circuit voltage (OCV), although the BSCF-based cathode was more benefitted more from infiltration than the LSCF-based one. Moreover, the application of cathodic overpotentials (−0.1 to −0.3 V) resulted in opposite effects on the LSCF-and BSCF-based cathodes, highlighting a different response of the oxygen vacancies to the applied voltage for the two perovskite compositions. The positive effect of the LSM layer was further confirmed by the observed improvement in long-term stability of both infiltrated perovskite-type systems. 1 They exhibit mixed ionic and electronic conductivity, with excellent charge and mass transfer properties 2 and high oxygen exchange surface coefficients. 3 Their excellent activity for oxygen reduction has been proved widely. [4][5][6][7][8][9][10] Although the structure and electrochemical processes of LSCF and BSCF are quite different, both of them have long-term stability and redox behavior issues to be clarified, in order to be used as cathode materials in commercial devices. Indeed, when used as cathodes in intermediate-temperatures solid oxide fuel cells (IT-SOFCs), they suffer from chemical and structural instability, which causes degradation during operation time. Moreover, the correlation between their redox behavior under electrochemical operating conditions is still unclear. Many studies have been devoted to investigating LSCF degradation and several causes have been reported, among them: i) mutual cations diffusion between interfaces with consequent atoms depletion and phase separation, [11][12][13][14][15][16] ii) LSCF grain coarsening, 17 iii) reactivity with YSZ-based electrolytes, even with ceria-based barrier layer, 18 iv) impurity contamination, namely Cr from metal interconnects and B from sealing when the cell is inside a stack.19-21 Some recent work performed on an LSCF/CGO (Ce 0.9 Gd 0.1 O 2-δ ) composite cathode on a YSZ electrolyte with a CGO barrier layer 11 affirms that Sr depletion, phase separation and cations inter-diffusion occur mainly during the fabrication process, with negligible contributions during long-term * Electrochemical Society Member.e Present Address: R&D Manufacturing Support Dept., Ansaldo Energia, Via Nicola Lorenzi 8, I-16152 Genoa. z E-mail: carpanese@unige.it operation (973 K). On the other hand, some previous works conversely found that LS...

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Section: Tga and Tpr Results-inmentioning

confidence: 78%

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δversus Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ

Giuliano

Carpanese

Clematis

et al. 2017

J. Electrochem. Soc.

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“…b) Temperature dependence of R p of the bare LSCF electrode and catalyst‐coated LSCF electrodes. Reported Pd, [ 57 ] GDC, [ 33,35 ] SSC, [ 36 ] LSCF, [ 36 ] BaCO 3 , [ 37 ] and PrBa 0.8 Ca 0.2 Co 2 O 5+δ with PrCoO 3‐δ (PrO x ) and BaCoO 3− δ [ 58 ] ‐coated LSCF electrodes were added for comparison from references. [ 33,35–37,58,57 ] c) DRT functions of the bare LSCF and MP catalyst‐coated LSCF electrodes at 750 °C.…”

Section: Resultsmentioning

confidence: 99%

“…[24][25][26][27][28][29] The catalyst coatings can increase the number of ORR active sites and protect LSCF from reacting with contaminates. [20,[30][31][32][33] Several types of catalysts have been developed, including precious metals (e.g., Pd, Ag, and Ru), oxygen ion-conducting oxides (Sm 0.2 Ce 0.8 O 2−δ [SDC], [34] and Gd 0.2 Ce 0.8 O 1.9 (GDC)), [33,35] mixed ionic and electronic conductors (e.g., LSCF, [36] Sm 0.5 Sr 0.5 CoO 3−δ (SSC), [36] and PrSrCoMnO 6−δ , [25] etc. ), and Ba-containing compounds (BaO, [26] and BaCO 3 [37] ).…”

Section: Introductionmentioning

confidence: 99%

Enhancing Oxygen Reduction Activity and Cr Tolerance of Solid Oxide Fuel Cell Cathodes by a Multiphase Catalyst Coating

Niu

Zhou

et al. 2021

Adv Funct Materials

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Intermediate temperature solid oxide fuel cells (IT‐SOFCs) are cost‐effective and efficient energy conversion systems. The sluggish oxygen reduction reaction (ORR) and the degradation of cathodes are critical challenges to the commercialization of IT‐SOFCs. Here, a highly efficient multiphase (MP) catalyst coating, consisting of Ba1−xCo0.7Fe0.2Nb0.1O3−δ (BCFN) and BaCO3, to enhance the ORR activity and durability of the state‐of‐the‐art lanthanum strontium cobalt ferrite (La0.6Sr0.4Co0.2Fe0.8O3−δ, LSCF) cathode is reported. The conformal MP catalyst‐coated LSCF cathode shows a polarization resistance (Rp) of 0.048 Ω cm2 at 650 °C, about one order of magnitude smaller than that of the bare LSCF. In an accelerated Cr‐poisoning test, the degradation rate of the catalyst‐coated LSCF electrode is 10−3 Ω cm2 h−1 (0.59% h−1) over 200 h, only one fifth of the degradation rate of the bare LSCF electrode at 750 °C. In addition, anode‐supported single cells with the MP catalyst‐coated LSCF cathode show a dramatically enhanced peak power density (1.4 W cm−2 vs 0.67 W cm−2 at 750 °C) and increased durability against Cr and H2O. Both experimental results and density functional theory‐based calculations indicate that the BCFN phase improves the ORR activity while the BaCO3 phase enhances the stability of the LSCF cathode.

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“…Besides, the requirement for operational temperatures exceeding 500 °C in ceramic solid oxide cells (SOC) leads to highly dynamic solid/solid and solid/gas interfaces because of both compositional and microstructural changes. 3 Therefore, thermally induced transformations occurring at the nanometer scale and below must be taken into account as they can be detrimental to the catalytic activity, including the segregation of inactive phases toward the surfaces, 4 particle formation and coarsening, 5 phase transitions, and decomposition at high temperatures. 6 The preparation technique, 7 coating conditions [substrate temperature ( T substrate ), background oxygen pressure ( p O 2 ) etc.…”

Section: Introductionmentioning

confidence: 99%

Surface Restructuring of Thin-Film Electrodes Based on Thermal History and Its Significance for the Catalytic Activity and Stability at the Gas/Solid and Solid/Solid Interfaces

Çelikbilek

Cavallaro

Kerherve

et al. 2020

ACS Appl. Mater. Interfaces

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Electrodes in solid-state energy devices are subjected to a variety of thermal treatments, from film processing to device operation at high temperatures. All these treatments influence the chemical activity and stability of the films, as the thermally induced chemical restructuring shapes the microstructure and the morphology. Here, we investigate the correlation between the oxygen reduction reaction (ORR) activity and thermal history in complex transition metal oxides, in particular, La 0.6 Sr 0.4 CoO 3−δ (LSC64) thin films deposited by pulsed laser deposition. To this end, three ∼200 nm thick LSC64 films with different processing and thermal histories were studied. A variety of surface-sensitive elemental characterization techniques ( i.e ., low-energy ion scattering, X-ray photoelectron spectroscopy, and secondary ion mass spectrometry) were employed to thoroughly investigate the cationic distribution from the outermost surface to the film/substrate interface. Moreover, electrochemical impedance spectroscopy was used to study the activity and the stability of the films. Our investigations revealed that, despite the initial comparable ORR activity at 600 °C, the degradation rates of the films differed by twofold in the long-term stability tests at 500 °C. Here, we emphasize the importance of processing and thermal history in the elemental surface distribution, especially for the stability of LSC64 electrodes and propose that they should be considered as among the main pillars in the design of active surfaces.

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Stability and performance of La0.6Sr0.4Co0.2Fe0.8O3-δ nanostructured cathodes with Ce0.8Gd0.2O1.9 surface coating

Cited by 39 publications

References 43 publications

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δversus Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δversus Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ

Enhancing Oxygen Reduction Activity and Cr Tolerance of Solid Oxide Fuel Cell Cathodes by a Multiphase Catalyst Coating

Surface Restructuring of Thin-Film Electrodes Based on Thermal History and Its Significance for the Catalytic Activity and Stability at the Gas/Solid and Solid/Solid Interfaces

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Stability and performance of La0.6Sr0.4Co0.2Fe0.8O3-δ nanostructured cathodes with Ce0.8Gd0.2O1.9 surface coating

Cited by 39 publications

References 43 publications

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La0.6Sr0.4Co0.2Fe0.8O3-δversus Ba0.5Sr0.5Co0.8Fe0.2O3-δ

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La0.6Sr0.4Co0.2Fe0.8O3-δversus Ba0.5Sr0.5Co0.8Fe0.2O3-δ

Enhancing Oxygen Reduction Activity and Cr Tolerance of Solid Oxide Fuel Cell Cathodes by a Multiphase Catalyst Coating

Surface Restructuring of Thin-Film Electrodes Based on Thermal History and Its Significance for the Catalytic Activity and Stability at the Gas/Solid and Solid/Solid Interfaces

Contact Info

Product

Resources

About

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δversus Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δversus Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ