Mitigation of the deleterious effect of silicon species on the conductivity of ceria electrolytes

Lane, Jonathan A.; Neff, Julia L.; Christie, G.M.

doi:10.1016/j.ssi.2006.02.024

Cited by 48 publications

(29 citation statements)

References 3 publications

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“…These insulating phases increase ohmic and polarization resistances, change the Ni particle size and distribution, and decrease the electrochemically active sites. A SiO 2 insulating layer also decreases the conductivity of Gd-doped CeO 2 electrolyte for low temperature SOFCs [125]. Increased H 2 O content in the cell accelerates the degradation due to the blocking effect of oxygen migration and increase in area specific resistance [126].…”

Section: Impact Of Seal Glass On Performance and Durability Of Solid mentioning

confidence: 99%

Seal glass for solid oxide fuel cells

Mahapatra

2010

Journal of Power Sources

180

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Section: Impact Of Seal Glass On Performance and Durability Of Solid mentioning

confidence: 99%

Seal glass for solid oxide fuel cells

Mahapatra

2010

Journal of Power Sources

180

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“…It is acknowledged that the siliceous impurity forms a resistive intergranular phase in GDC. 2,[12][13][14][15][16][17][18][19][20] Thus, the 200-250-fold increase in the gb sp value caused by the addition of 500-2000 ppm SiO 2 in the present study can be attributed to the blocking of the ionic conduction by the siliceous intergranular phase.…”

Section: Resultsmentioning

confidence: 88%

“…Lane et al 17 reported that the grain-boundary conduction of GDC containing SiO 2 impurity can be enhanced to a great extent by the addition of CaO and SrO. They attributed this to the formation of second phases containing both Ca and Si at the grain triple points.…”

Section: Resultsmentioning

confidence: 99%

“…Zhang et al 14 and Jasinski et al 16 reported that the grain-boundary resistivity of a Gd 0.2 Ce 0.8 O 1.9 specimen was increased 6-30 times by the addition of 200-3000 ppm SiO 2 . Lane et al 17 suggested that the addition of CaO or SrO improves the grain-boundary conduction of GDC containing SiO 2 impurity. The authors [18][19][20] further investigated the mechanism underlying the enhancement of the grain-boundary conduction upon doping with CaO and SrO.…”

mentioning

confidence: 99%

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SiO[sub 2]-Tolerant Grain-Boundary Conduction in Sr- and Mg-Doped Lanthanum Gallate

Cho

Jung

et al. 2010

Electrochem. Solid-State Lett.

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The effect of SiO 2 impurity on the grain-boundary conduction in Sr-and Mg-doped lanthanum gallate ͑La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3−␦ , LSGM͒ was studied. The grain-boundary conduction of LSGM was slightly affected, even by the addition of 500-2000 ppm SiO 2 , while the apparent grain-boundary resistivity was increased up to ϳ780 times in gadolinia-doped ceria by the doping of 500-2000 ppm SiO 2 . The high tolerance of the grain-boundary conduction against siliceous impurity in the LSGM specimen was explained by the gathering of the acidic siliceous phase near the basic SrO component.The grain boundary of stabilized zirconia is typically 10 2 -10 4 times more resistive than the grain interior. 1,2 The depletion of oxygen vacancies near the grain boundary is dominant in highly pure specimens. 1,3 SiO 2 impurities even at low concentrations of hundreds of ppm deteriorate the grain-boundary conduction to a great extent. 4-6 Siliceous impurity is a ubiquitous element that can easily be incorporated during ceramic processing, sintering, and fuel cell operation. 7 Accordingly, the negative role of the siliceous intergranular phase cannot be excluded even in relatively pure materials.The operation of solid oxide fuel cells ͑SOFCs͒ at low temperature ͑LT͒ or intermediate temperature ͑IT͒ ͑400-700°C͒ is advantageous from the viewpoint of the operational stability, the quick startup, and the use of cost-effective gas sealing and interconnecting materials. 8-10 Gadolinia-doped ceria ͑GDC͒ and Sr-and Mg-doped lanthanum gallate ͑La 1−x Sr x Ga 1−y Mg y O 3−␦ , LSGM͒ are the two most representative electrolytes for LT-and IT-SOFCs on account of their high ionic conductivities. 7,11 The extrinsic deterioration of the grain-boundary conduction by siliceous contamination becomes more significant in the LT and IT regimes.It has been reported that the role of siliceous impurity in the grain-boundary conduction of GDC is analogous to that in stabilized zirconia. 12-16 Gerhardt and Nowick 12 reported that a 6 mol % Gd 2 O 3 -doped CeO 2 specimen containing 1000 ppm of SiO 2 showed a significantly larger grain-boundary arc in the impedance spectra than the same specimen with Ͻ10 ppm of SiO 2 . Zhang et al. 14 and Jasinski et al. 16 reported that the grain-boundary resistivity of a Gd 0.2 Ce 0.8 O 1.9 specimen was increased 6-30 times by the addition of 200-3000 ppm SiO 2 . Lane et al. 17 suggested that the addition of CaO or SrO improves the grain-boundary conduction of GDC containing SiO 2 impurity. The authors 18-20 further investigated the mechanism underlying the enhancement of the grain-boundary conduction upon doping with CaO and SrO. In addition, the authors 21,22 suggested MgO and BaO as other promising additives to mitigate the effect of the harmful siliceous intergranular phase.LSGM contains Sr and Mg elements that might play the role of scavenger materials for the siliceous impurity in the GDC system. Thus, the effect of the SiO 2 impurity on the grain-boundary conduction in LSGM is expected to be different from that in GDC...

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“…tamanho médio de cristalito aumentou com a adição de cálcio e lítio, sendo maior para este último.O valor do parâmetro de rede calculado para a céria-gadolínia sem a introdução de aditivos corresponde ao encontrado na literatura[15,71]. Adições de cálcio e lítio promoveram pequenas mudanças neste parâmetro, porém esta variação não chega a ser significativa, pois está dentro da incerteza experimental.A figura 31 mostra as micrografias de superfícies de fratura (a) e polida e atacada termicamente (b) da céria-gadolínia co-precipitada e sinterizada a 1500°C por 4 h.…”

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Influência do cálcio e do lítio na sinterização e na condutividade elétrica do óxido de cério contendo gadolínio

Porfirio¹

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Gostaria de agradecer... à Dra. Eliana N. S. Muccillo pela orientação e confiança durante todo o decorrer deste trabalho, ao Dr. Reginaldo Muccillo pelas sugestões e discussões, ao IPEN pela oportunidade de realizar este trabalho, ao CNPq pela bolsa de mestrado concedida, à Dra. Eliana Aricó pelas medidas de dilatometria, ao Dr. Valter Ussui pelas medidas de adsorção gasosa, a todos os doutores, mestres e técnicos do CCTM pelas discussões, análises realizadas e, que de alguma forma, contribuíram para o desenvolvimento deste trabalho, à Dra. Sandra K. Tadokoro pela paciência e por ter me ensinado tudo que sei hoje sobre co-precipitação, não poderia esquecer de agradecer à Dra.

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Mitigation of the deleterious effect of silicon species on the conductivity of ceria electrolytes

Cited by 48 publications

References 3 publications

Seal glass for solid oxide fuel cells

Seal glass for solid oxide fuel cells

SiO[sub 2]-Tolerant Grain-Boundary Conduction in Sr- and Mg-Doped Lanthanum Gallate

Influência do cálcio e do lítio na sinterização e na condutividade elétrica do óxido de cério contendo gadolínio

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