Nanostructured SOFC Electrode Scaffolds Prepared via High Temperature<i>in situ</i>Carbon Templating of Hybrid Materials

Muhoza, Sixbert P.; Barrett, Taylor; Soll, S. E.; Gross, Michael D.

doi:10.1149/07801.1407ecst

Cited by 5 publications

(10 citation statements)

References 6 publications

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“…Mixed ionic electronic conductor (MIEC) plays the vital role in the application of energy conversion and storage devices possesses excellent mechanical durability and electrochemical functionality [10]. MIECs such as (Y, La, Nb, Fe, Mo, Ni, Mn) doped SrTiO 3 perovskites [11][12][13][14][15], SrTiO 3 /YSZ [16,17], and SrTiO 3 /GDC [18,19] composites have been reported in the literature for the application as electrode materials in SOFC. Yttria stabilized zirconia (YSZ) is the most commonly used electrolyte ionic conductor.…”

Section: Introductionmentioning

confidence: 99%

The analysis of charge transport mechanism in mixed ionic electronic conductor composite of Sr₂TiCoO₆ double perovskite with yttria stabilized zirconia

Saini¹,

Balani²,

Maiti³

2021

J. Phys.: Condens. Matter

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In this investigation, the ionic conduction mechanism in mixed ionic electronic conductors composites of Sr2TiCoO6/YSZ has been studied with the help of universal dynamic response. 3 mol% and 8 mol% yttria stabilized ZrO2 have been mixed with Sr2TiCoO6 (STC) double perovskite in 1:1 ratio to prepare STC/3YSZ and STC/8YSZ composites via solid-state reaction route. AC Impedance spectroscopy has been carried out to examine the charge transport mechanism, which has been modeled using the microstructural networks of resistors and capacitors. Grain boundaries are more resistive and capacitive compared to the bulk. Modulus spectroscopy analysis demonstrates the non-Debye character of conductivity relaxation with frequency. Complex frequency-dependent AC conductivity is found to obey Almond West power law and reveals that ion migration occurs through the correlated hopping mechanism. Further, the DC conductivity and relaxation time have been found to follow the Barton Nakajima and Namikawa relation, which is correlated with AC to DC conduction. The time-temperature superposition principle has been used to explain the conductivity scaling in the intermediate frequency range. At low temperatures, the ions are localized in the asymmetric potential well, while at high temperatures, hopping behavior starts dominating. Further Kramers–Kronig transformation connects the dielectric strength with conductivity relaxation and verifies the impedance data.

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Section: Introductionmentioning

confidence: 99%

The analysis of charge transport mechanism in mixed ionic electronic conductor composite of Sr₂TiCoO₆ double perovskite with yttria stabilized zirconia

Saini¹,

Balani²,

Maiti³

2021

J. Phys.: Condens. Matter

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“…YSZ-Propylene Oxide-Glucose (YSZ-POG) hybrid materials were prepared following the same procedure that was used in our previously reported works. [1][2][3][4] Briefly, stoichiometric amounts of ZrCl 4 (99.5+%, Alfa Aesar), Y(NO 3 ) 3 •6H 2 O (99.9%, Alfa Aesar), and glucose (≥ 99.9%, Alfa Aesar) were sequentially dissolved in deionized water and magnetically stirred until complete dissolution. Propylene Oxide (PO, ≥ 99.5%, Sigma-Aldrich) was then added to the solution and stirred for about five minutes, after which a translucent yellow gel formed.…”

Section: Methodsmentioning

confidence: 99%

“…We recently developed a processing method that produces high surface area mixed-metal-oxides (up to 99 m 2 • g −1 ) in the 850 • C-1350 • C temperature range. [1][2][3][4] The processing method is referred to as the in situ carbon templating method and has been shown to work for numerous ceramics used in solid oxide fuel cell (SOFC) electrodes, including yttria-stabilized zirconia (YSZ), gadolinia-doped ceria (GDC), lanthanum-strontium-cobalt-iron-oxide (LSCF), and strontium titanate (STO). The in situ carbon templating method involves two steps.…”

mentioning

confidence: 99%

“…In the second step, the amorphous carbon is burned away at 700 • C in air, a temperature low enough to preserve the ceramic nanoparticles. We have shown that the processing method works for two hybrid materials: (1) propylene oxide gels with a glucose additive to vary the carbon template concentration [1][2][3][4] and (2) citric acid gels; the carbon template concentration is controlled by the concentration of citric acid. 3,4 We have also shown that the surface area of nano-YSZ prepared with this approach is still high after 2000 hours at 500 • C (65 m 2 • g −1 ) and 700 • C (35 m 2 • g −1 ).…”

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confidence: 99%

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Processing Nano-YSZ in Solid Oxide Fuel Cells: The Effect of Sintering Atmosphere on Thermochemical Stability

Muhoza

Mccormack

Garrett

et al. 2019

J. Electrochem. Soc.

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The thermochemical stability of nanoscale yttria-stabilized-zirconia (nYSZ), processed via in situ carbon templating, was studied between 850 • C-1350 • C in four sintering atmospheres: Ar, N 2 , H 2 , and humidified H 2 . The in situ carbon templating method generates nanoscale ceramic particles surrounded by an amorphous carbon template upon sintering. The carbon template is subsequently removed by low temperature oxidation, leaving behind nanoscale ceramic particles. In Ar and H 2 , a ZrC impurity formed at temperatures ≥1150 • C. In humidified H 2 , either a ZrC impurity formed or the carbon template oxidized. In N 2 , ZrC was not observed over the temperature range studied and the carbon template was preserved. After carbon template removal, the nYSZ surface areas were high for Ar, H 2 , and N 2 : 55-99 m 2 • g −1 . For humidified H 2 , nYSZ surface area decreased as the carbon template was lost. Finally, nYSZ, processed in N 2 at 850 • C and 1250 • C, was integrated into symmetric YSZ-Lanthanum Strontium Ferrite (YSZ-LSF) cathode cells. The addition of nYSZ decreased cathode non-ohmic resistance, at 550 • C in air, by 40% and 27% for nYSZ processed at 850 • C and 1250 • C, respectively. This work demonstrates that N 2 is a thermochemically stable atmosphere for in situ carbon templating and that the resulting nYSZ considerably improves electrode performance.

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“…PO hybrid materials of YSZ (YSZ-PO) were synthesized with ZrCl 4 (99.5+%, Alfa Aesar), Y(NO 3 ) 3 • 6H 2 O (99.9%, Alfa Aesar), glucose (≥ 99.9%, Alfa Aesar), and PO (≥ 99.5%, Sigma-Aldrich) as described in detail elsewhere. [41][42][43] The salts were dissolved in deionized water in a Zr:Y:H 2 O molar ratio of 5.75:1:650 with magnetic stirring. Glucose was then dissolved in the solution and PO was subsequently added to the solution.…”

Section: Methodsmentioning

confidence: 99%

High Surface Area SOFC Electrode Materials Prepared at Traditional Sintering Temperatures

Muhoza

Barrett

Cottam

et al. 2018

J. Electrochem. Soc.

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Solid oxide fuel cell (SOFC) electrode materials with surface areas up to 99 m 2 • g −1 were prepared at traditional sintering temperatures, 1050 • C-1350 • C, by sintering hybrid inorganic-organic materials in an inert atmosphere followed by calcination in air at 700 • C. The electrode materials investigated were yttria-stabilized zirconia (YSZ), lanthanum strontium cobalt ferrite (LSCF), gadolinia doped ceria (GDC), and strontium titanate (STO). During sintering, an amorphous carbon template forms in situ and remains throughout the sintering process, aiding in the creation and preservation of mixed-metal-oxide nanomorphology. The carbon template is removed during subsequent calcination in air at 700 • C, leaving behind a nanostructured ceramic. Phase stability, carbon template concentration, and specific surface area was determined for each mixed-metal-oxide. Final specific surface areas up to 83, 66, 95, and 99 m 2 • g −1 were achieved for YSZ, LSCF, GDC, and STO, respectively. The impact of high surface area YSZ on symmetrical YSZ-lanthanum strontium ferrite (LSF) cathode cell performance was evaluated in the temperature range of 550 • C-800 • C. Adding nanostructured YSZ decreased the electrochemical impedance by 45% at 550 • C. The performance improvement lessened with increasing temperature, and at 800 • C there was essentially no improvement. The findings reveal a promising approach to improving low temperature SOFC performance.

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Nanostructured SOFC Electrode Scaffolds Prepared via High Temperaturein situCarbon Templating of Hybrid Materials

Cited by 5 publications

References 6 publications

The analysis of charge transport mechanism in mixed ionic electronic conductor composite of Sr₂TiCoO₆ double perovskite with yttria stabilized zirconia

The analysis of charge transport mechanism in mixed ionic electronic conductor composite of Sr₂TiCoO₆ double perovskite with yttria stabilized zirconia

Processing Nano-YSZ in Solid Oxide Fuel Cells: The Effect of Sintering Atmosphere on Thermochemical Stability

High Surface Area SOFC Electrode Materials Prepared at Traditional Sintering Temperatures

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Nanostructured SOFC Electrode Scaffolds Prepared via High Temperaturein situCarbon Templating of Hybrid Materials

Cited by 5 publications

References 6 publications

The analysis of charge transport mechanism in mixed ionic electronic conductor composite of Sr2TiCoO6 double perovskite with yttria stabilized zirconia

The analysis of charge transport mechanism in mixed ionic electronic conductor composite of Sr2TiCoO6 double perovskite with yttria stabilized zirconia

Processing Nano-YSZ in Solid Oxide Fuel Cells: The Effect of Sintering Atmosphere on Thermochemical Stability

High Surface Area SOFC Electrode Materials Prepared at Traditional Sintering Temperatures

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The analysis of charge transport mechanism in mixed ionic electronic conductor composite of Sr₂TiCoO₆ double perovskite with yttria stabilized zirconia

The analysis of charge transport mechanism in mixed ionic electronic conductor composite of Sr₂TiCoO₆ double perovskite with yttria stabilized zirconia