Cold sintering-assisted densification of GDC electrolytes for SOFC applications

Murutoglu, Murat; Ucun, Tugce; Ulasan, Ozge; Büyükaksoy, Aligül; Tür, Yahya Kemal; Yılmaz, Hüseyin

doi:10.1016/j.ijhydene.2022.01.043

Cited by 14 publications

(5 citation statements)

References 33 publications

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“…CeO 2 ceramics are known to be nearly insoluble in water, unlike Na 2 CO 3 which has a very high solubility limit (∼34 gr/100 mL at 25 • C). 45,56 Therefore, it was believed that the carbonate phase, which dissolved in water easily in huge quantities and enabled rapid mass transport with the aid of pressure and temperature, was responsible for the increases in density. Due to its high solubility limit in water, some of the dissolved carbonates during processing leaked with the water from the mold, therefore, water contents more than 4 wt.% could not be studied.…”

Section: Densification By Cold Sintering Of Sdc-30n Nano-compositesmentioning

confidence: 99%

“…40,36,44 In some cases, a heat treatment step in conventional sintering ovens may be needed for densification afterwards, such as YSZ, CeO 2 , etc. 37,42,45 Even so, the densification temperatures during the heat treatment step were much lower than the ones normally utilized in the sintering of these materials. For example, Gd doped ceria (GDC) could be sintered to 96% of its theoretical density by first cold and then conventionally sintering it at 1100 • C. Conventional sintering of GDC requires temperatures in excess of 1450 • C. 46,47 In this study, Sm doped CeO 2 (SDC)-Na 2 CO 3 nanocomposite electrolytes have been densified at much lower temperatures than those normally reported in the literature by using a novel technique called cold sintering processing in a single step.…”

Section: Introductionmentioning

confidence: 97%

“…Depending on the material of choice, the cold sintering processing may be enough to fully densify the material, such as ZnO, BaTiO 3 , NASICON, etc 40,36,44 . In some cases, a heat treatment step in conventional sintering ovens may be needed for densification afterwards, such as YSZ, CeO 2 , etc 37,42,45 . Even so, the densification temperatures during the heat treatment step were much lower than the ones normally utilized in the sintering of these materials.…”

Section: Introductionmentioning

confidence: 99%

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One step densification of SDC—Na₂CO₃ nano‐composite electrolytes for SOFC applications by cold sintering process

et al. 2023

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Sm0.2Ce0.8O1.9‐ 30% Na2CO3 (Sm doped ceria (SDC)‐30N) nano‐composite electrolytes were densified in a single step via cold sintering process (CSP). At 200°C and 450 MPa of uniaxial pressure, samples up to 97% of their theoretical density could be obtained. The effect of processing parameters, such as temperature, uniaxial pressure, processing duration, and moisture content, on the densification of the nano‐composite electrolytes was investigated. The thermal, microstructural, and electrical properties of nano‐composites were investigated by differential scanning calorimetry, X‐ray diffractometer, scanning electron microscope, and EIS analysis. SDC crystallite sizes were found to be around 25 nm, barely coarsened after CSP by which the true nano nature of the nano‐composite could be preserved. Because, by conventional processing high density values could not be attained and high processing temperatures in excess of 600°C had to be used, promoting particle coarsening. The highest total electrical conductivity was found to be 2.2 × 10−2 S cm−1 at 600°C, with an activation energy of 0.83 eV for SDC‐30N nano‐composites. The present investigation revealed that the implementation of cold sintering technique resulted in significant enhancements in the densification of nano‐composite electrolytes, thereby rendering them suitable for efficient utilization in SOFC applications, as compared to the conventional production methods.

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Section: Densification By Cold Sintering Of Sdc-30n Nano-compositesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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One step densification of SDC—Na₂CO₃ nano‐composite electrolytes for SOFC applications by cold sintering process

et al. 2023

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“…Jaiswal N. et.al. [54] reported values of ionic conductivity of 0.01 S cm −1 for Ce 0.9 Gd 0.1 O 1.95 and 3.02 × 10 −3 S cm −1 for Ce 0.85 Gd 0.15 O 1.925 at 500 • C. Murutoglu M. et al [55] used the cold sintering-assisted densification of GDC and reported activation energy of 0.69 eV at a high temperature range. Zhang J. et.…”

Section: Characterization Of the Pelletsmentioning

confidence: 99%

Synthesis and Electron-Beam Evaporation of Gadolinium-Doped Ceria Thin Films

et al. 2022

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Gadolinium-doped ceria (GDC) nanopowders, prepared using the co-precipitation synthesis method, were applied as a starting material to form ceria-based thin films using the electron-beam technique. The scanning electron microscopy (SEM )analysis of the pressed ceramic pellets’ cross-sectional views showed a dense structure with no visible defects, pores, or cracks. The AC impedance spectroscopy showed an increase in the total ionic conductivity of the ceramic pellets with an increase in the concentration of Gd2O3 in GDC. The highest total ionic conductivity was obtained for Gd0.1Ce0.9O2-δ (σtotal is 11 × 10−3 S∙cm−1 at 600 °C), with activation energies of 0.85 and 0.67 eV in both the low- and high-temperature ranges, respectively. The results of the X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma optical emission spectrometer (ICP-OES) measurements revealed that the stoichiometry for the evaporated thin films differs, on average, by ~28% compared to the target material. The heat-treatment of the GDC thin films at 600 °C, 700 °C, 800 °C, and 900 °C for 1 h in the air had a minor effect on the surface roughness and the morphology. The results of Raman spectroscopy confirmed the improvement of the crystallinity for the corresponding thin films. The optimum heat-treating temperature for thin films does not exceed 800 °C.

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“…30 This technique involves pressing a mixture of particles and a precursor solution under high pressure and at elevated temperatures to achieve highly dense ceramics. CSP has also been successfully employed to prepare densified gadolinia-doped ceria (GDC) by Murutoglu et al, 31 who were able to obtain gastight GDC electrolytes with theoretical densities of up to 96% after sintering at 1100 • C. However, various solvents used in the cold sintering process such as deionized water (heat-treated at 1400 • C), 32 HNO 3 /H 2 O 2 mixture (the relative density of GDC is ∼90%), 24 and molten hydroxides flux solvents (introduced K + and Na + in GDC) 33 have been unable to produce pure and dense GDC ceramics at lower temperatures. Recently, the concept of reactive cold sintering has been introduced for soda-lime glass and BaTiO 3 , 34,35 which enables simultaneous synthesis and densification, offering a green, efficient, and economical way to fabricate dense ceramics.…”

Section: Introductionmentioning

confidence: 99%

Improved densification in cold sintering of gadolinia‐doped ceria with reactive sintering aids

Zhao,

Tang,

et al. 2023

J Am Ceram Soc.

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This study explores a novel reactive cold sintering method for improving the density of gadolinia‐doped ceria (GDC) ceramics while reducing the annealing temperature. Instead of using deionized water as an aid in conventional cold sintering, stoichiometrically mixed Ce(NO3)3·6H2O and Gd(NO3)3·6H2O precursors were added as additives during the CSP in this study. The effects of processing parameters such as sintering temperature and additive content on the relative density of the compacts were investigated using synthesized GDC and commercial GDC powders as raw materials. The results showed that with the aid of precursors, GDC ceramics were sintered up to 90% of their theoretical densities at 850°C and up to 94% at 950°C when the synthesized nanopowder GDC was used. Additionally, the sintering mechanism was investigated, and it was found that the GDC generated by the precursor reaction effectively filled the gaps between the original particles, promoting densification of the sample after cold‐pressing.

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Cold sintering-assisted densification of GDC electrolytes for SOFC applications

Cited by 14 publications

References 33 publications

One step densification of SDC—Na₂CO₃ nano‐composite electrolytes for SOFC applications by cold sintering process

One step densification of SDC—Na₂CO₃ nano‐composite electrolytes for SOFC applications by cold sintering process

Synthesis and Electron-Beam Evaporation of Gadolinium-Doped Ceria Thin Films

Improved densification in cold sintering of gadolinia‐doped ceria with reactive sintering aids

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Cold sintering-assisted densification of GDC electrolytes for SOFC applications

Cited by 14 publications

References 33 publications

One step densification of SDC—Na2CO3 nano‐composite electrolytes for SOFC applications by cold sintering process

One step densification of SDC—Na2CO3 nano‐composite electrolytes for SOFC applications by cold sintering process

Synthesis and Electron-Beam Evaporation of Gadolinium-Doped Ceria Thin Films

Improved densification in cold sintering of gadolinia‐doped ceria with reactive sintering aids

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One step densification of SDC—Na₂CO₃ nano‐composite electrolytes for SOFC applications by cold sintering process

One step densification of SDC—Na₂CO₃ nano‐composite electrolytes for SOFC applications by cold sintering process