Effect of Cr2O3 on the 18O tracer incorporation in SOFC materials

Finsterbusch, Martin; Lussier, A.; Negusse, Ezana; Zhu, Zihua; Smith, Richard J.; Schaefer, J.A.; Idzerda, Y. U.

doi:10.1016/j.ssi.2010.03.007

Cited by 19 publications

(21 citation statements)

References 29 publications

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“…This indicates the SrCrO 4 formation at the LSCF cathode surface by the following possible reactions: 1) trapping of Cr and deposition of Cr are accelerated at the Pt-mesh/LSCF interface during cathode reaction and 2) Sr-transports to the surface of LSCF porous structures to form SrCrO 4 . Sr-segregation in LSCF has been reported by several authors [17][18][19], and the present result can be related with the instability of LSCF cathode under polarized condition. If we assume grain boundary diffusion of Sr in LSCF, relatively long distance diffusion of Sr is calculated through the porous LSCF cathode.…”

Section: Methodssupporting

confidence: 79%

Degradation Mechanism of SOFC Cathodes under CrO₃ and SO₂ Impurity Exposures

et al. 2013

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The effects of Cr-and S-impurities on the cathode performances were examined at the mixed ionic-electronic conducting La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) cathode. Under exposures to CrO 3 and SO 2 , the cathode performance decreased drastically by forming SrCrO 4 and SrSO 4 at the LSCF grain surfaces and electrochemical active sites. The main degradation factors of LSCF cathode was the decrease of surface reaction rates by the impurities. The Sr-diffusion and depletion in the LSCF structures can affect the cathode performance degradation. Relatively large amounts of Sr were depleted in the LSCF grains under CrO 3 exposures by forming a thick SrCrO 4 at the Pt-mesh/LSCF cathode interfaces, while small amounts of Sr-depletion in the LSCF grains under SO 2 exposures.

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Section: Methodssupporting

confidence: 79%

Degradation Mechanism of SOFC Cathodes under CrO₃ and SO₂ Impurity Exposures

et al. 2013

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“…Although no data are available for Cr diffusion in LSCF, there are data published by Waernhus et al 31 for Cr diffusion in La 0.9 Sr 0.1 FeO 3-δ . Finsterbusch et al 12 report that in their experiments a chromia surface layer had no detectable effect on the oxygen tracer diffusion coefficient. From Waernhus et al at 900 • C the Cr diffusion coefficients are approximately 6 × 10 −21 m 2 s −1 for lattice diffusion and 3 × 10 −16 m 2 s -1 for grain boundary diffusion.…”

Section: Discussionmentioning

confidence: 94%

“…C chem was calculated from the experimental data for t chem and R chem and is plotted as a function of temperature for different Cr concentrations in Figure 10. Finsterbusch et al 12 studied the effect of Cr 2 O 3 over-layers on the oxygen tracer surface exchange constant, k*, for dense bulk specimens of LSCF6428 at 800 • C. They report that k* was approximately 2 × 10 −8 m s −1 for the Cr-free surface and gradually reduced with increasing Cr surface coverage, saturating at approximately 10 −9 m s −1 for chromia layer thicknesses greater than 12-15 nm. The results in Figure 10 also show that C chem tends to increase with Cr concentration.…”

Section: Discussionmentioning

confidence: 99%

Effect of Chromium on La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δSolid Oxide Fuel Cell Cathodes

Lee

Atkinson

Kilner

2013

J. Electrochem. Soc.

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The transfer of chromium from metallic components into the cathode of a solid oxide fuel cell (SOFC) can severely degrade its performance and is known as 'chromium poisoning'. In this study we investigate the relationship between the amount of chromium introduced into La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ , LSCF (6428), cathodes and their electrochemical performance, and clarify further the poisoning mechanism. LSCF cathodes were screen printed onto Ce 0.9 Gd 0.1 O 1.95 electrolyte pellets and infiltrated with Cr(NO 3 ) 3 solutions to different Cr levels up to 2 wt%. Electrochemical impedance spectroscopy at 500-800 • C showed that even very low levels of Cr give a significant increase in cathode polarization resistance, which increases with Cr concentration. The impedance response was analyzed using the model of Adler, Lane and Steele to extract oxygen self-diffusion (D O ) and surface exchange (k O ) parameters for the LSCF. The results show that Cr reduces both D O and k O , the latter being the more affected. However, the activation energies for polarization resistance, D O and k O are not significantly affected by Cr content. This indicates that the Cr poisoning mechanism involves the de-activation of sites for oxygen exchange on the LSCF surface and that the cathode's residual activity is by means of remaining active sites.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 155.97.178.73 Downloaded on 2014-11-26 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 155.97.178.73 Downloaded on 2014-11-26 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 155.97.178.73 Downloaded on 2014-11-26 to IP F634 Journal of The Electrochemical Society, 160 (6) F629-F635 (2013) ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 155.97.178.73 Downloaded on 2014-11-26 to IP

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“…In addition, the ASR of Nd 2 Ni 0.95 Cu 0.05 O 4+δ cathode was lower than that of LSCF cathode below 700°C. Finsterbusch et al [19] studied that the chromium oxide coating on LSCF can result in the drastic decrease in the effective surface exchange coefficients kchem, which is considered to be responsible for the drastic increase in the ASR value of the LSCF cathode. Yang et al [20] addressed that the kchem of Nd 2 NiO 4+δ with 30 nm Cr was slightly decreased from the level of the sample without Cr-layer for 1000 h at 600°C.…”

Section: Resultsmentioning

confidence: 99%

Cr Poisoning On Nd2Ni0.95Cu0.05O4+δ Cathode for Solid Oxide Fuel Cells

Choe

Lee

Hwang

2016

Archives of Metallurgy and Materials

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In this study, Nd2Ni1-xCuxO4+δ (x=0, 0.05, 0.1, and 0.2) layered perovskite powders were synthesized by the glycine nitrate process (GNP) and the chromium poisoning effect on the electrochemical performance of the Nd2Ni0.95Cu0.05O4+δ and La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes were investigated. In the case of the LSCF cathode, the strontium chromite phase formed after the exposure of the gaseous chromium species, while there was no additional phase in the Nd2Ni0.95Cu0.05O4+δ cathode. The area specific resistance (ASR) of the Nd2Ni0.95Cu0.05O4+δ cathode did not change significantly after the exposure of the gaseous chromium species at 800°C.

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Effect of Cr2O3 on the 18O tracer incorporation in SOFC materials

Cited by 19 publications

References 29 publications

Degradation Mechanism of SOFC Cathodes under CrO₃ and SO₂ Impurity Exposures

Degradation Mechanism of SOFC Cathodes under CrO₃ and SO₂ Impurity Exposures

Effect of Chromium on La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δSolid Oxide Fuel Cell Cathodes

Cr Poisoning On Nd2Ni0.95Cu0.05O4+δ Cathode for Solid Oxide Fuel Cells

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Effect of Cr2O3 on the 18O tracer incorporation in SOFC materials

Cited by 19 publications

References 29 publications

Degradation Mechanism of SOFC Cathodes under CrO3 and SO2 Impurity Exposures

Degradation Mechanism of SOFC Cathodes under CrO3 and SO2 Impurity Exposures

Effect of Chromium on La0.6Sr0.4Co0.2Fe0.8O3-δSolid Oxide Fuel Cell Cathodes

Cr Poisoning On Nd2Ni0.95Cu0.05O4+δ Cathode for Solid Oxide Fuel Cells

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Product

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Degradation Mechanism of SOFC Cathodes under CrO₃ and SO₂ Impurity Exposures

Degradation Mechanism of SOFC Cathodes under CrO₃ and SO₂ Impurity Exposures

Effect of Chromium on La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δSolid Oxide Fuel Cell Cathodes