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Defferriere T, Klotz D, Gonzalez-Rosillo JC, Rupp JLM, Tuller HL. Photo-enhanced ionic conductivity across grain boundaries in polycrystalline ceramics. NATURE MATERIALS 2022; 21:438-444. [PMID: 35027718 DOI: 10.1038/s41563-021-01181-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 12/01/2021] [Indexed: 05/06/2023]
Abstract
Grain boundary conductivity limitations are ubiquitous in material science. We show that illumination with above-bandgap light can decrease the grain boundary resistance in solid ionic conductors. Specifically, we demonstrate the increase of the grain boundary conductance of a 3 mol% Gd-doped ceria thin film by a factor of approximately 3.5 at 250 °C and the reduction of its activation energy from 1.12 to 0.68 eV under illumination, while light-induced heating and electronic conductivity could be excluded as potential sources for the observed opto-ionic effect. The presented model predicts that photo-generated electrons decrease the potential barrier heights associated with space charge zones depleted in charge carriers between adjacent grains. The discovered opto-ionic effect could pave the way for the development of new electrochemical storage and conversion technologies operating at lower temperatures and/or higher efficiencies and could be further used for fast and contactless control or diagnosis of ionic conduction in polycrystalline solids.
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Affiliation(s)
- Thomas Defferriere
- Department of Material Science and Engineering, MIT, Cambridge, MA, USA.
| | - Dino Klotz
- Department of Material Science and Engineering, MIT, Cambridge, MA, USA.
- International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, Fukuoka, Japan.
| | - Juan Carlos Gonzalez-Rosillo
- Department of Material Science and Engineering, MIT, Cambridge, MA, USA
- Catalonia Institute for Energy Research (IREC), Sant Adrià del Besòs (Barcelona), Spain
| | - Jennifer L M Rupp
- Department of Material Science and Engineering, MIT, Cambridge, MA, USA
- Department of Chemistry, Technical University of Munich, München, Germany
| | - Harry L Tuller
- Department of Material Science and Engineering, MIT, Cambridge, MA, USA.
- International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, Fukuoka, Japan.
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2
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Construction of mesoporous ceria-supported gold catalysts with rich oxygen vacancies for efficient CO oxidation. J RARE EARTH 2022. [DOI: 10.1016/j.jre.2021.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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Wulfmeier H, Kohlmann D, Defferriere T, Steiner C, Moos R, Tuller HL, Fritze H. Thin-film chemical expansion of ceria based solid solutions: laser vibrometry study. Z PHYS CHEM 2021. [DOI: 10.1515/zpch-2021-3125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The chemical expansion of Pr0.1Ce0.9O2–δ
(PCO) and CeO2–δ
thin films is investigated in the temperature range between 600 °C and 800 °C by laser Doppler vibrometry (LDV). It enables non-contact determination of nanometer scale changes in film thickness at high temperatures. The present study is the first systematic and detailed investigation of chemical expansion of doped and undoped ceria thin films at temperatures above 650 °C. The thin films were deposited on yttria stabilized zirconia substrates (YSZ), operated as an electrochemical oxygen pump, to periodically adjust the oxygen activity in the films, leading to reversible expansion and contraction of the film. This further leads to stresses in the underlying YSZ substrates, accompanied by bending of the overall devices. Film thickness changes and sample bending are found to reach up to 10 and several hundred nanometers, respectively, at excitation frequencies from 0.1 to 10 Hz and applied voltages from 0–0.75 V for PCO and 0–1 V for ceria. At low frequencies, equilibrium conditions are approached. As a consequence maximum thin-film expansion of PCO is expected due to full reduction of the Pr ions. The lower detection limit for displacements is found to be in the subnanometer range. At 800 °C and an excitation frequency of 1 Hz, the LDV shows a remarkable resolution of 0.3 nm which allows, for example, the characterization of materials with small levels of expansion, such as undoped ceria at high oxygen partial pressure. As the correlation between film expansion and sample bending is obtained through this study, a dimensional change of a free body consisting of the same material can be calculated using the high resolution characteristics of this system. A minimum detectable dimensional change of 5 pm is estimated even under challenging high-temperature conditions at 800 °C opening up opportunities to investigate electro-chemo-mechanical phenomena heretofore impossible to investigate. The expansion data are correlated with previous results on the oxygen nonstoichiometry of PCO thin films, and a defect model for bulk ceria solid solutions is adopted to calculate the cation and anion radii changes in the constrained films during chemical expansion. The constrained films exhibit anisotropic volume expansion with displacements perpendicular to the substrate plane nearly double that of bulk samples. The PCO films used here generate high total displacements of several 100 nm’s with high reproducibility. Consequently, PCO films are identified to be a potential core component of high-temperature actuators. They benefit not only from high displacements at temperatures where most piezoelectric materials no longer operate while exhibiting, low voltage operation and low energy consumption.
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Affiliation(s)
- Hendrik Wulfmeier
- Clausthal University of Technology, Institute of Energy Research and Physical Technologies , 38640 Goslar , Germany
| | - Dhyan Kohlmann
- Clausthal University of Technology, Institute of Energy Research and Physical Technologies , 38640 Goslar , Germany
| | - Thomas Defferriere
- Massachusetts Institute of Technology , Department of Materials Science and Engineering , Cambridge , MA , 02139 , USA
| | - Carsten Steiner
- University of Bayreuth , Department of Functional Materials , 95440 Bayreuth , Germany
| | - Ralf Moos
- University of Bayreuth , Department of Functional Materials , 95440 Bayreuth , Germany
| | - Harry L. Tuller
- Massachusetts Institute of Technology , Department of Materials Science and Engineering , Cambridge , MA , 02139 , USA
| | - Holger Fritze
- Clausthal University of Technology, Institute of Energy Research and Physical Technologies , 38640 Goslar , Germany
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4
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An in-depth multi-technique characterization of rare earth carbonates – RE2(CO3)3.2H2O – owning tengerite-type structure. J RARE EARTH 2021. [DOI: 10.1016/j.jre.2021.09.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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5
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High Pressure X-ray Diffraction as a Tool for Designing Doped Ceria Thin Films Electrolytes. COATINGS 2021. [DOI: 10.3390/coatings11060724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rare earth-doped ceria thin films are currently thoroughly studied to be used in miniaturized solid oxide cells, memristive devices and gas sensors. The employment in such different application fields derives from the most remarkable property of this material, namely ionic conductivity, occurring through the mobility of oxygen ions above a certain threshold temperature. This feature is in turn limited by the association of defects, which hinders the movement of ions through the lattice. In addition to these issues, ionic conductivity in thin films is dominated by the presence of the film/substrate interface, where a strain can arise as a consequence of lattice mismatch. A tensile strain, in particular, when not released through the occurrence of dislocations, enhances ionic conduction through the reduction of activation energy. Within this complex framework, high pressure X-ray diffraction investigations performed on the bulk material are of great help in estimating the bulk modulus of the material, and hence its compressibility, namely its tolerance toward the application of a compressive/tensile stress. In this review, an overview is given about the correlation between structure and transport properties in rare earth-doped ceria films, and the role of high pressure X-ray diffraction studies in the selection of the most proper compositions for the design of thin films.
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6
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Artini C, Massardo S, Carnasciali MM, Joseph B, Pani M. Evaluation of the Defect Cluster Content in Singly and Doubly Doped Ceria through In Situ High-Pressure X-ray Diffraction. Inorg Chem 2021; 60:7306-7314. [PMID: 33929819 PMCID: PMC8277124 DOI: 10.1021/acs.inorgchem.1c00433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Defect aggregates
in doped ceria play a crucial role in blocking
the movement of oxygen vacancies and hence in reducing ionic conductivity.
Nevertheless, evaluation of their amount and the correlation between
domain size and transport properties is still an open issue. Data
derived from a high-pressure X-ray diffraction investigation performed
on the Ce1–x(Nd0.74Tm0.26)xO2–x/2 system are employed to develop a novel approach aimed at
evaluating the defect aggregate content; the results are critically
discussed in comparison to the ones previously obtained from Sm- and
Lu-doped ceria. Defect clusters are present even at the lowest considered x value, and their content increases with increasing x and decreasing rare earth ion (RE3+) size;
their amount, distribution, and spatial correlation can be interpreted
as a complex interplay between the defects’ binding energy,
nucleation rate, and growth rate. The synoptic analysis of data derived
from all of the considered systems also suggests that the detection
limit of the defects by X-ray diffraction is correlated to the defect
size rather than to their amount, and that the vacancies’ flow
through the lattice is hindered by defects irrespective of their size
and association degree. A
novel approach to the treatment of high-pressure X-ray
diffraction data is applied to several rare earth-doped ceria systems
with the aim of providing an evaluation of the amount of defect aggregates
and of the composition of the CeO2-based solid solution.
By this method, it is possible to effectively correlate the structural
properties and ionic conductivity of the studied material.
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Affiliation(s)
- Cristina Artini
- DCCI, Department of Chemistry and Industrial Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova, Italy.,Institute of Condensed Matter Chemistry and Technologies for Energy, National Research Council, CNR-ICMATE, Via De Marini 6, 16149 Genova, Italy
| | - Sara Massardo
- DCCI, Department of Chemistry and Industrial Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova, Italy
| | - Maria Maddalena Carnasciali
- DCCI, Department of Chemistry and Industrial Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova, Italy.,INSTM, Genova Research Unit, Via Dodecaneso 31, 16146 Genova, Italy
| | - Boby Joseph
- Elettra-Sincrotrone Trieste S.C.p.A., ss 14, km 163.5, Basovizza, 34149 Trieste, Italy
| | - Marcella Pani
- DCCI, Department of Chemistry and Industrial Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova, Italy.,CNR-SPIN Genova, Corso Perrone 24, 16152 Genova, Italy
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Audasso E, Kim Y, Cha J, Cigolotti V, Jeong H, Jo YS, Kim Y, Choi SH, Yoon SP, Nam SW, Sohn H. In situ exsolution of Rh nanoparticles on a perovskite oxide surface: Efficient Rh catalysts for Dry reforming. KOREAN J CHEM ENG 2020. [DOI: 10.1007/s11814-020-0592-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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GDC-Based Infiltrated Electrodes for Solid Oxide Electrolyzer Cells (SOECs). APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10113882] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In this work, porous complex and metal-free cathodes based on a (La0.6Sr0.4) (Cr0.5Mn0.5) O3 (LSCM) screen-printed backbone infiltrated with Ce0.9Gd0.1O2 (GDC) were fabricated for solid oxide electrolyzer cells. GDC infiltration has been optimized by structural and microstructural investigation and tested by electrochemical measurements in CO/CO2 mixtures. Infiltrated electrodes with a non-aqueous GDC solution showed the best electro-catalytic activity towards CO2 reduction, exhibiting a much lower polarization resistance, i.e., Rpol = 0.3 Ω·cm2 at 900 °C. The electrochemical performance of LSCM/GDCE in terms of Rpol is comparable to the best-performing Ni-YSZ cathode in the same operating conditions (Rpol = 0.23 Ω·cm2).
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9
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Turco R, Bonelli B, Armandi M, Spiridigliozzi L, Dell’Agli G, Deorsola F, Esposito S, Di Serio M. Active and stable ceria-zirconia supported molybdenum oxide catalysts for cyclooctene epoxidation: Effect of the preparation procedure. Catal Today 2020. [DOI: 10.1016/j.cattod.2019.10.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Shaikh SPS, Rode CV. Rational synthesis of 10GDC electrolyte through a microwave irradiation GNP facile route for SOFC applications. RSC Adv 2020; 10:3020-3028. [PMID: 35496134 PMCID: PMC9048589 DOI: 10.1039/c9ra09476h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 01/06/2020] [Indexed: 11/21/2022] Open
Abstract
The gadolinium-doped ceria Gd0.1Ce0.9O1.95 (10GDC) powder was synthesized using a microwave-synthesized glycine nitrate process (MS-GNP). The powder was subsequently pressed into circular pellets and sintered at various temperatures viz. 800, 900, 1000 and 1200 °C, in a microwave, high temperature furnace for 4 h so as to investigate the effect of the sintering temperature and sintering environment on the structural, morphological, thermal and electrical properties. The crystallite size and particle size as observed from X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) are found to be in the range of 15-28 nm and 12-20 nm, respectively. The electrochemical impedance spectroscopy (EIS) analysis was carried out to study the electrochemical properties during the cooling cycle from 400 °C to 800 °C. The highest value of ionic conductivity (3.55 × 10-1 S cm-1) is observed at an operating temperature of 800 °C and O2 gas partial pressure of 1 atm. Further, it is observed that the sintering temperature has a significant effect on the surface morphology and crystallite size, thereby improving the electrical performance of the samples. Though 20GDC was used as an electrolyte in the authors' previous study, the novelty of the present work is the synthesis of 10GDC using a microwave-assisted glycine nitrate process and the size (thickness) of the prepared electrolyte for use in a Solid Oxide Fuel Cell (SOFC), which plays a major role in enhancing the structural, morphological and electrochemical properties with respect to different sintering temperatures as compared to the reported data. Hence, the prepared 10GDC electrolyte may be treated as one of the promising candidates as an electrolyte for SOFC for intermediate as well as high temperature applications.
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Affiliation(s)
- S P S Shaikh
- Department of Physics, Savitribai Phule Pune University Ganeshkhind Road Pune-411007 Maharashtra India
| | - Chandrashekhar V Rode
- Chemical Engineering and Process Development Division, National Chemical Laboratory Pune 411008 India +91 9923199822
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11
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Morphology and Structural Stability of Bismuth-Gadolinium Co-Doped Ceria Electrolyte Nanopowders. INORGANICS 2019. [DOI: 10.3390/inorganics7100118] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The reduction of the sintering temperature of doped ceria ceramics remains an open challenge for their real exploitation as electrolytes for intermediate temperature solid oxide fuel cell (IT-SOFCs) at the industrial level. In this work, we have used Bi (0.5 and 2 mol %) as the sintering aid for Gd (20 mol %)-doped ceria. Nano-sized powders of Bi/Gd co-doped ceria were easily synthesized via a simple and cheap sol-gel combustion synthesis. The obtained powders showed high sinterability and very good electrochemical properties. More importantly, even after prolonged annealing at 700 °C, both of the powders and of the sintered pellets, no trace of structural modifications, phase instabilities, or Bi segregation appeared. Therefore, the use of a small amount of Bi can be taken into account for preparing ceria-based ceramic electrolytes at low sintering temperatures.
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12
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Chae JW, Park YK, Magnone E, Park JH. Oxygen permeation properties of Sm/Sr co-doped ceria decorated Ba0.5Sr0.5Co0.8Fe0.2O3-δ hollow fiber membrane. J IND ENG CHEM 2019. [DOI: 10.1016/j.jiec.2019.04.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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New Insights in the Hydrothermal Synthesis of Rare-Earth Carbonates. MATERIALS 2019; 12:ma12132062. [PMID: 31252523 PMCID: PMC6651494 DOI: 10.3390/ma12132062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 06/21/2019] [Accepted: 06/25/2019] [Indexed: 11/26/2022]
Abstract
The rare-earth carbonates represent a class of materials with great research interest owing to their intrinsic properties and because they can be used as template materials for the formation of other rare earth phases, particularly of rare-earth oxides. However, most of the literature is focused on the synthesis and characterization of hydroxycarbonates. Conversely, in the present study we have synthesized both rare-earth carbonates—with the chemical formula RE2(CO3)3·2-3H2O, in which RE represents a generic rare-earth element, and a tengerite-type structure with a peculiar morphology—and rare-earth hydroxycarbonates with the chemical formula RECO3OH, by hydrothermal treatment at low temperature (120 °C), using metal nitrates and ammonium carbonates as raw materials, and without using any additive or template. We found that the nature of the rare-earth used plays a crucial role in relation to the formed phases, as predicted by the contraction law of lanthanides. In particular, the hydrothermal synthesis of rare-earth carbonates with a tengerite-type structure was obtained for the lanthanides from neodymium to erbium. A possible explanation of the different behaviors of lighter and heavier rare-earths is given.
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Spiridigliozzi L, Pinter L, Biesuz M, Dell'Agli G, Accardo G, Sglavo VM. Gd/Sm-Pr Co-Doped Ceria: A First Report of the Precipitation Method Effect on Flash Sintering. MATERIALS 2019; 12:ma12081218. [PMID: 31013962 PMCID: PMC6514829 DOI: 10.3390/ma12081218] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 12/02/2022]
Abstract
In this work, ceria-based ceramics with the composition Gd0.14Pr0.06Ce0.8O2-δ and Sm0.14Pr0.06Ce0.8O2-δ, were synthesized by a simple co-precipitation process using either ammonium carbonate or ammonia solution as a precipitating agent. After the calcination, all of the produced samples were constituted by fluorite-structured ceria only, thus showing that both dopant and co-dopant cations were dissolved in the fluorite lattice. The ceria-based nanopowders were uniaxially compacted and consequently flash-sintered using different electrical cycles (including current-ramps). Different results were obtained as a function of both the adopted precipitating agent and the applied electrical cycle. In particular, highly densified products were obtained using current-ramps instead of “traditional” flash treatments (with the power source switching from voltage to current control at the flash event). Moreover, the powders that were synthesized using ammonia solution exhibited a low tendency to hotspot formation, whereas the materials obtained using carbonates as the precipitating agent were highly inhomogeneous. This points out for the first time the unexpected relevance of the precipitating agent (and of the powder shape/degree of agglomeration) for the flash sintering behavior.
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Affiliation(s)
- Luca Spiridigliozzi
- Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via G. Di Biasio 43, 03043 Cassino (FR), Italy.
| | - Lorenzo Pinter
- Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123 Trento, Italy.
| | - Mattia Biesuz
- Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123 Trento, Italy.
| | - Gianfranco Dell'Agli
- Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via G. Di Biasio 43, 03043 Cassino (FR), Italy.
| | - Grazia Accardo
- Center of Hydrogen-Fuel Cell Research, Korea Institute of Science and Technology, Hwarangno 14-gil, Seongbuk-gu, Seoul 136-791, Korea.
| | - Vincenzo M Sglavo
- Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123 Trento, Italy.
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Controlled Coprecipitation of Amorphous Cerium-Based Carbonates with Suitable Morphology as Precursors of Ceramic Electrolytes for IT-SOFCs. MATERIALS 2019; 12:ma12050702. [PMID: 30818832 PMCID: PMC6427277 DOI: 10.3390/ma12050702] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 02/15/2019] [Accepted: 02/26/2019] [Indexed: 11/29/2022]
Abstract
To be suitable as electrolytes in intermediate temperature solid oxide fuel cell (IT-SOFC), ceramic precursors have to be characterized by high sintering aptitude for producing fully densified products which are needed for this kind of application. Therefore, synthesis processes able to prepare highly reactive powders with low costs are noteworthy to be highlighted. It has been shown that amorphous coprecipitates based on cerium doped (and codoped) hydrated hydroxycarbonates can lead to synthesized ceramics with such desired characteristics. These materials can be prepared by adopting a simple coprecipitation technique using ammonium carbonate as precipitating agent. As a function of both the molar ratio between carbonate anions and total metallic cations, and the adopted mixing speed, the coprecipitate can be either amorphous, owning a very good morphology, or crystalline, owning worse morphology, packing aptitude, and sinterability. The amorphous powders, upon a mild calcination step, gave rise to the formation of stable solid solutions of fluorite-structured ceria maintaining the same morphology of the starting powders. Such calcined powders are excellent precursors for sintering ceramic electrolytes at low temperatures and with very high electrical conductivity in the intermediate temperature range (i.e., 500–700 °C). Therefore, irrespective of the actual composition of ceria-based systems, by providing an accurate control of both chemical conditions and physical parameters, the coprecipitation in the presence of ammonium carbonate can be considered as one of the most promising synthesis route in terms of cost/effectiveness to prepare excellent ceramic precursors for the next generation of IT-SOFC solid electrolytes.
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