Influence of codoping on the conductivity of Sc-doped zirconia by first-principles calculations and experiments

Xue, Qiannan; Wang, L.G.; Huang, Xiaowei; Zhang, J.X.; Zhang, H.

doi:10.1016/j.matdes.2018.09.001

Cited by 17 publications

(11 citation statements)

References 51 publications

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“…However, when larger cation Ca 2+ was added to the system this long-range ordering was suppressed due to the formation of eight-fold coordination between dopant and anionic sites, which results in a lower aging rate. 18,27,32,37 As the amount of Ca 2+ in 0.2Ca11SSZ was very low, it could be estimated that similar to undoped11SSZ, it may also have an enhancement in the rhombohedral phase during aging. Still, the presence of Ca 2+ suppresses the aging ∼1.2 times compared to 11SSZ.…”

Section: Resultsmentioning

confidence: 99%

Role of Divalent Co-Dopant as Structure Stabilizer in Scandia-Stabilized Zirconia Electrolyte for SOFC

Mathur,

Shin,

Hanantyo

et al. 2023

J. Electrochem. Soc.

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The present investigation reports the role of divalent binary co-dopant (Ca2+) in 11 mol% scandia stabilized zirconia (11SSZ) electrolytes to resolve its severe long-term aging issue for application in solid oxide fuel cells (SOFC). Dense electrolytes were formulated via the solid-state reaction method and their crystal structure was identified by X-ray diffractometer (XRD). To examine total electrical conductivity and its stability in oxidizing and reducing atmosphere DC four-point probe measurement was used. Among all the compositions, 0.2Ca11SSZ demonstrates the highest conductivity of 0.075 S cm−1 at 800 °C, with excellent stability of 6.7%/100 h in a reducing (97 vol% H2/3 vol% H2O) atmosphere. However, the presence of 0.5 mol% calcium in 11SSZ results in more than threefold suppression of aging rate compared to undoped11SSZ i.e. 2.19%/200 h in air atmosphere at 800 °C. Additionally, the doping of divalent Ca2+ widens the electrolytic domain up to pO2 ∼ 10−26 atm at 1000 °C compared to state-of-art 8YSZ (pO2 ∼ 10−22 atm), with 0.024% linear expansion on phase transition and 172 MPa flexural strength. Convincingly, the excellent structure stability and ionic conductivity of calcium co-doped 11SSZ compared to state-of-the-art electrolytes make them potential candidates to be used as an electrolyte for SOFC application.

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Section: Resultsmentioning

confidence: 99%

Role of Divalent Co-Dopant as Structure Stabilizer in Scandia-Stabilized Zirconia Electrolyte for SOFC

Mathur,

Shin,

Hanantyo

et al. 2023

J. Electrochem. Soc.

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“…Co-doping of scandium and yttrium into zirconia (ScYSZ) has been reported in the literature [8][9][10][11][12][13]. The incorporation of Y 3+ and Sc 3+ as co-dopants into ZrO 2 structure can either stabilize the cubic/tetragonal phase to achieve a better or desired property such as higher conductivity as compared to single doping [8][9][10][11] and can provide good mechanical and thermal stability desirable for certain applications [14]. On the other hand, the fabrication of solid electrolytes into thin films may further increase the conductivity and is crucial for the development of a micron-sized SOEC system (µ-SOEC).…”

Section: Introductionmentioning

confidence: 99%

Effects of Oxygen Partial Pressure and Substrate Temperature on the Structure and Morphology of Sc and Y Co-Doped ZrO2 Solid Electrolyte Thin Films Prepared via Pulsed Laser Deposition

et al. 2022

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Scandium (Sc) and yttrium (Y) co-doped ZrO2 (ScYSZ) thin films were prepared on a SiO2-Si substrate via pulsed laser deposition (PLD) method. In order to obtain good quality thin films with the desired microstructure, various oxygen partial pressures (PO2) from 0.01 Pa to 10 Pa and substrate temperatures (Ts) from 25 °C to 800 °C were investigated. X-ray diffraction (XRD) patterns results showed that amorphous ScYSZ thin films were formed at room substrate temperature while cubic polycrystalline thin films were obtained at higher substrate temperatures (Ts = 200 °C, 400 °C, 600 °C, 800 °C). Raman spectra revealed a distinct Raman shift at around 600 cm−1 supporting a cubic phase. However, a transition from cubic to tetragonal phase can be observed with increasing oxygen partial pressure. Photoemission spectroscopy (PES) spectra suggested supporting analysis that more oxygen vacancies in the lattice can be observed for samples deposited at lower oxygen partial pressures resulting in a cubic structure with higher dopant cation binding energies as compared to the tetragonal structure observed at higher oxygen partial pressure. On the other hand, dense morphologies can be obtained at lower PO2 (0.01 Pa and 0.1 Pa) while more porous morphologies can be obtained at higher PO2 (1.0 Pa and 10 Pa).

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“…However, not all aliovalent dopants are equally suitable. The ionic conductivity of electrolytes depends on dopant atomic radii, dopant concentration, electrostatic interactions between dopants and oxygen vacancies, and phase composition [1,2]. It was found that the optimal concentration of dopants is around 8-10 mol.% [3].…”

Section: Introductionmentioning

confidence: 99%

“…The conductivity decreases at higher or lower dopant concentrations due to dopant clustering or a low number of oxygen vacancies [4]. Zirconia doped with 10 mol.% of Sc (10ScSZ) exhibit the highest conductivity at 1000 • C among all ZrO 2 based electrolytes due to low association enthalpy of the defect reactions and similar ionic radii (0.075 nm-Sc 3+ , 0.072 nm-Zr 4+ ) [2,5]. However, the conductivity becomes equal or lower to the conductivity of YSZ at 500 • C due to increased activation energy [6].…”

Section: Introductionmentioning

confidence: 99%

Structural and Electrochemical Properties of Scandia Alumina Stabilized Zirconia Thin Films

et al. 2021

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This work presents a systematic investigation of scandia alumina stabilized zirconia (ScAlSZ, composition: ZrO2:Sc2O3:Al2O3 93:6:1 wt.%) thin films (~2 μm). Thin films were formed by the e-beam evaporation method on 450 °C substrates. The influence of Al concentration on thin film microstructure, structure, and electrochemical properties was characterized by EDS, XRD, Raman, and EIS methods. It was found that the aluminum concentration in the deposited thin films decreased with an increase in the deposition rate. The concentration of Al changed from 15.9 to 3.8 at.% when the deposition rates were 0.2 and 1.6 nm/s, respectively. The crystallinity of the thin films depended strongly on the concentration of Al, resulting in an amorphous phase when Al concentration was 22.2 at.% and a crystalline phase when Al concentration was lower. ScAlSZ thin films containing 15.9 at.% of Al had monoclinic and tetragonal phases, while thin films with 1.6 and 3.8 at.% of Al had a mixture of cubic, tetragonal, and monoclinic phases. The phase transition was observed during the thermal annealing process. Cubic and rhombohedral phases formed in addition to monoclinic and tetragonal phases appeared after annealing ScAlSZ thin films containing 15.9 and 22.2 at.% of aluminum. The highest total ionic conductivity (σbulk = 2.89 Sm−1 at 800 °C) was achieved for ScAlSZ thin films containing 3.8 at.% of Al. However, thin films containing a higher concentration of aluminum had more than 10 times lower total conductivity and demonstrated changes in activation energy at high temperatures (>560 °C). Activation energies changed from ~1.10 to ~1.85 eV.

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Influence of codoping on the conductivity of Sc-doped zirconia by first-principles calculations and experiments

Cited by 17 publications

References 51 publications

Role of Divalent Co-Dopant as Structure Stabilizer in Scandia-Stabilized Zirconia Electrolyte for SOFC

Role of Divalent Co-Dopant as Structure Stabilizer in Scandia-Stabilized Zirconia Electrolyte for SOFC

Effects of Oxygen Partial Pressure and Substrate Temperature on the Structure and Morphology of Sc and Y Co-Doped ZrO2 Solid Electrolyte Thin Films Prepared via Pulsed Laser Deposition

Structural and Electrochemical Properties of Scandia Alumina Stabilized Zirconia Thin Films

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