Effects of strontium gallate additions on sintering behavior of gadolinia-doped ceria

Lee, Joo-Sin

doi:10.1007/s10832-006-7775-1

Cited by 10 publications

(6 citation statements)

References 11 publications

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“…Adding a small amount of Sr to doped-ceria has been proved very effective in reducing the sintering temperature of ceria. [37][38][39] It should be noted here that the densification observed in this experiment is not as pronounced as that observed when the SDC is in contact with the LSCF cathode for only 2 hours at 1200 • C. This could be due to the larger gas phase diffusion distance or higher potential for loss of gas phase species to the surrounding atmosphere.…”

Section: Resultsmentioning

confidence: 58%

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SrZrO₃Formation at the Interlayer/Electrolyte Interface during (La_1-xSr_x)_1-δCo_1-yFe_yO₃Cathode Sintering

Darvish

Hardy

et al. 2017

J. Electrochem. Soc.

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This work probes the formation of SrZrO 3 at the SDC/YSZ interface (Sm doped ceria, SDC; Y stabilized zirconia, YSZ) during (La 1-x Sr x ) 1-δ Co 1-y Fe y O 3 (LSCF) cathode sintering. SEM/EDS and grazing incidence X-ray diffraction results of annealed LSCF and YSZ samples reveal that even without physical contact between LSCF and YSZ, SrZrO 3 was formed on the surface of YSZ, preferentially at the grain boundaries. It was suspected that the SrZrO 3 formation is due to the Sr-containing gas species diffused through the pores of the SDC layer and reacted with the YSZ electrolyte. Computational thermodynamics was adopted to predict the gas species formed in air during sintering by using the La-Sr-Co-Fe-O-H thermodynamic database. Sr(OH) 2 is identified as the dominant Sr-containing gas species under the experimental conditions. In addition, it was found that A-site deficiency in LSCF could effectively suppress the SrZrO 3 formation while a dense and pore-free SDC interlayer is required to totally block the SrZrO 3 formation. Cell performance was significantly improved for a cell with a dense SDC interlayer fabricated by pulsed laser deposition, due to elimination of SrZrO 3 formation and therefore reduced interfacial resistance. • C). LSCF materials exhibit electrochemical activity toward oxygen reduction that is superior to Sr-doped LaMnO 3 (LSM), an SOFC cathode material widely used at temperatures above 800• C. 1-8 However, LSCF materials also show higher chemical reactivity with the state-of-the-art electrolyte material, yttria stabilized zirconia (YSZ), than LSM. Reports have shown that LSCF reacts with YSZ to form an insulating La 2 Zr 2 O 7 (LZO) or SrZrO 3 (SZO) layer between the cathode and electrolyte at temperatures as low as 900• C, while LSM essentially does not react with YSZ until 1200• C. 9-16 Therefore, for LSCF to be used as a cathode, an interlayer is necessary between the cathode and electrolyte to prevent these detrimental reactions from occurring during cathode sintering and cell operation. Sm-or Gd-doped ceria (SDC or GDC) is usually used as the interlayer because it is chemically compatible with both the LSCF cathode and the YSZ electrolyte at high temperatures. 2,5,[9][10][11]14 An interlayer of high density is desirable to reduce the ohmic resistance in the interlayer. The sinterability of the SDC interlayer is influenced by several factors, such as the method of fabrication, initial particle size, sintering temperature, etc. Fuel cells with a dense doped ceria interlayer fabricated by either pulsed laser deposition or magnetron sputtering show a pronounced increase in power density. 17,18The significant increase in power density is attributed to decreased ohmic resistance, due to the improved density of the interlayer, better interfacial contact between the SDC and YSZ layers, and decreased insulating reaction products at this interface. Interlayers fabricated by other methods such as screen printing, dip coating, tape casting, or spray coating usually contain a certain amount of porosit...

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Section: Resultsmentioning

confidence: 58%

“…[37][38][39] It should be noted here that the densification observed in this experiment is not as pronounced as that observed when the SDC is in contact with the LSCF cathode for only 2 hours at 1200…”

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confidence: 52%

SrZrO₃Formation at the Interlayer/Electrolyte Interface during (La_1-xSr_x)_1-δCo_1-yFe_yO₃Cathode Sintering

Darvish

Hardy

et al. 2017

J. Electrochem. Soc.

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“…23,24 It is also reported that small addition of Sr 2 Ga 2 O 5 considerably improved sinterability of Gd-doped CeO 2 . 25 In this study, Sr-substituted LLZ-Ga, Li 6.25+x Ga 0.25 La 3-x Sr x Zr 2 O 12 (LLZ-GaSr), was synthesized to improve sinterability and ionic conductivity of LLZ-Ga. The relationship between composition, structure, sinterability and ionic conductivity of LLZ-GaSr is discussed.…”

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confidence: 99%

Synthesis, Structure and Ionic Conductivity of Garnet Like Lithium Ion Conductor Li_6.25+_xGa_0.25La_3-_xSr_xZr₂O₁₂

Mori

Sugimoto

Matsuda

et al. 2018

J. Electrochem. Soc.

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Lithium ionic conductors which exhibit high ionic conductivity and are stable to lithium metal are demanded as solid electrolytes of all solid-state lithium batteries. Garnet-type lithium ionic conductor, Li 6.25+x Ga 0.25 La 3-x Sr x Zr 2 O 12 (LLZ-GaSr) has been synthesized at 1000 • C by a solid-state reaction. Its phase relation, sinterability, structure and ionic conductivities have been investigated. LLZ-GaSr forms cubic phase in x = 0-0.2 as main phase, while it forms tetragonal phase with impurities in x = 0.3-0.5. XRD studies indicate the solubility limit in cubic phase of LLZ-GaSr is around x = 0.1. Sinterability is improved by Sr substitution. The total ionic conductivity of LLZ-GaSr with x = 0.1 at 25 • C exhibits 1.3 × 10 −3 S cm -1 . The symmetrical cell with Li electrodes demonstrates that LLZ-GaSr is stable in Li metal at room temperature for 1.5 month. The Sr-substitution is effective in improvements of sinterability and ionic conductivity of Li 6.25 Ga 0.25 La 3 Zr 2 O 12 (LLZ-Ga).

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“…[2][3][4][5][6][7][8][9] Most of the investigators have studied the preparation of ultra fine ceria-based ceramic powders by chemical routes such as coprecipitation and sol-gel process. Recently, it has been reported that Ga 2 O 3 , [10][11][12] Al 2 O 3 , [13,14] MnO 2 , [15] Fe 2 O 3 , [16] Co 3 O 4 , [17] CoO, [18] and Sr 2 Ga 2 O 5 [19,20] are effective sintering aids for the densification of ceria-based ceramics.…”

Section: Introductionmentioning

confidence: 99%

Electrical properties of Ga2O3-added Ce0.8Gd0.2O1.9 ceramics prepared by commercial powders

Kim

Choi

Park

et al. 2011

Electron. Mater. Lett.

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The electrical properties of Ga2O3-added Ce0.8Gd0.2O1.9 ceramics were investigated. The gadolinia-doped ceria powders were prepared by using commercially available powders. Dense Ce0.8Gd0.2O1.9 ceramics with 96.5% of the theoretical density could be obtained by sintering the milled mixture with 0.5 mol % Ga2O3 addition at 1400°C for 5 h. The total conductivity of the 0.5 mol % Ga2O3-added specimen showed a maximum conductivity of 7.14 × 10 −3 Ω −1 ·cm −1 at 500°C. Pure Ce0.8Gd0.2O1.9 ceramics needed to be sintered at 1600°C in order to obtain an equivalent theoretical density and conductivity. The introduction of Ga2O3 doping had a good effect on the electrical conductivity of gadolinia-doped ceria.

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Effects of strontium gallate additions on sintering behavior of gadolinia-doped ceria

Cited by 10 publications

References 11 publications

SrZrO₃Formation at the Interlayer/Electrolyte Interface during (La_1-xSr_x)_1-δCo_1-yFe_yO₃Cathode Sintering

SrZrO₃Formation at the Interlayer/Electrolyte Interface during (La_1-xSr_x)_1-δCo_1-yFe_yO₃Cathode Sintering

Synthesis, Structure and Ionic Conductivity of Garnet Like Lithium Ion Conductor Li_6.25+_xGa_0.25La_3-_xSr_xZr₂O₁₂

Electrical properties of Ga2O3-added Ce0.8Gd0.2O1.9 ceramics prepared by commercial powders

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Effects of strontium gallate additions on sintering behavior of gadolinia-doped ceria

Cited by 10 publications

References 11 publications

SrZrO3Formation at the Interlayer/Electrolyte Interface during (La1-xSrx)1-δCo1-yFeyO3Cathode Sintering

SrZrO3Formation at the Interlayer/Electrolyte Interface during (La1-xSrx)1-δCo1-yFeyO3Cathode Sintering

Synthesis, Structure and Ionic Conductivity of Garnet Like Lithium Ion Conductor Li6.25+xGa0.25La3-xSrxZr2O12

Electrical properties of Ga2O3-added Ce0.8Gd0.2O1.9 ceramics prepared by commercial powders

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SrZrO₃Formation at the Interlayer/Electrolyte Interface during (La_1-xSr_x)_1-δCo_1-yFe_yO₃Cathode Sintering

SrZrO₃Formation at the Interlayer/Electrolyte Interface during (La_1-xSr_x)_1-δCo_1-yFe_yO₃Cathode Sintering

Synthesis, Structure and Ionic Conductivity of Garnet Like Lithium Ion Conductor Li_6.25+_xGa_0.25La_3-_xSr_xZr₂O₁₂