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Co-sintering of Cu-CGO cermet anodes on CGO (Ce0.8Gd0.2O2−δ) electrolyte was conducted at low temperature (1000 °C) by introducing small amounts (2 mol.%) of CuO sintering aid to the
electrolytic CGO. The Cu-CGO anodes with Cu contents from 20–50 vol.% were prepared by combustion synthesis followed by sintering
and reduction. Symmetrical anode/electrolyte/anode assemblies of Cu-GCO/CGO/Cu-CGO were fabricated by manually depositing
the anode combustion powder on a green substrate of the 2 mol% CuO-containing CGO, followed by co-pressing and co-sintering
of the assembly at 1000 °C. The low-temperature sintered CGO is submicron with 95–99% relative density. CuO addition has no
significant effect on either the total or ionic conductivity of the electrolyte, but p-type conduction in the temperature
range, 900–1200 °C, is 25 times higher than that of undoped CGO. Oxygen-ion transference numbers of the Cu-containing CGO
lie in the range 0.89–0.99, as determined by the modified e.m.f. technique under an oxygen/air potential gradient. The activation
energy for ionic conduction, 83 kJmol−1, is significantly lower than that for p-type electronic transport, 140 kJmol−1.
Paper presented at the 9th EuroConference on Ionics, Ixia, Rhodes, Greece, Sept. 15 – 21, 2002. 相似文献
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Y. Z. Chen N. Pryds J. Schou S. Linderoth 《Applied Physics A: Materials Science & Processing》2011,105(3):697-701
Epitaxial growth of Ce0.8Gd0.2O2(CGO) films on (001) TiO2-terminated SrTiO3 substrates by pulsed laser deposition was investigated using in situ reflective high energy electron diffraction. The initial
film growth shows a Stransky–Krastanov growth mode. However, this three-dimensional island formation is replaced by a two-dimensional
island nucleation during further deposition, which results in atomically smooth CGO films. The obtained high-quality CGO films
may be attractive for the electrolyte of solid-oxide fuel cells operating at low temperature. 相似文献
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K. Rodrigo S. Heiroth N. Pryds L. Theil Kuhn V. Esposito S. Linderoth J. Schou T. Lippert 《Applied Physics A: Materials Science & Processing》2011,104(3):845-850
Ultrathin crystalline films of 10 mol% gadolinia-doped ceria (CGO10) are grown on MgO (100) substrates by pulsed laser deposition
at a moderate temperature of 400°C. As-deposited CGO10 layers of approximately 4 nm, 14 nm, and 22 nm thickness consist of
fine grains with dimensions ≤∼11 nm. The films show high density within the thickness probed in the X-ray reflectivity experiments.
Thermally activated grain growth, density decrease, and film surface roughening, which may result in the formation of incoherent
CGO10 islands by dewetting below a critical film thickness, are observed upon heat treatment at 400°C and 800°C. The effect
of the grain coarsening on the electrical characteristics of the layers is investigated and discussed in the context of a
variation of the number density of grain boundaries. The results are evaluated with regard to the use of ultrathin CGO10 films
as seeding templates for the moderate temperature growth of thick solid electrolyte films with improved oxygen transport properties. 相似文献
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The use of a double-layer ceria-gadolinia (CGO) - yttria-stabilized zirconia (YSZ) electrolyte has been suggested as an alternative
for efficient intermediate temperature operation of Solid Oxide Fuel Cells (SOFC). CGO offers the advantage of high ionic
conductivity and good chemical compatibility with Co-containing cathode perovskite materials, while YSZ serves as an electron
blocking layer. The main problem for the applicability of such a composite film still remains the formation of a poorly conductive
solid solution phase at the CGO/YSZ interface. The microstructure and the elemental distribution of this solid solution phase
were examined with the aid of electronic probe microanalysis. Powders with the same composition were synthesized in order
to examine their crystal structure and electrical properties, with the objective to propose a suitable gradation at the interface
in order to improve the feasibility of CGO/YSZ two- layer composite electrolyte films.
Paper presented at the 5th Euroconference on Solid State Ionics, Benalmádena, Spain, Sept. 13–20, 1998 相似文献
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《Solid State Ionics》2006,177(19-25):2075-2079
The effects of gadolinia-doped ceria (CGO, Ce0.8Gd0.2O1.9−x) and yttria-doped zirconia (8YSZ, Zr0.92Y0.08O2−x) interlayers prepared by spray pyrolysis between vacuum plasma-sprayed 8YSZ electrolytes (8YSZ–VPS) and screen-printed (La0.8Sr0.2)0.98MnO3 cathodes (LSM) on the power output of solid oxide fuel cells (SOFC) are investigated. Amorphous thin films are deposited and then converted to nanocrystalline electrolyte–cathode interlayers during the first heat-up cycle of a SOFC to the operating temperature. CGO thin films between the YSZ plasma-sprayed electrolyte and the LSM cathode increased the power output by more than 20% compared to cells without interlayers, whereas YSZ films degraded the power output of cells. It is assumed that CGO improves the charge transfer at the electrolyte–cathode interface and that the CGO layer prevents the formation of undesirable insulation of La-zirconate at the interface 8YSZ/LSM. 相似文献
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Min Liu Dongqi Shi Hongli Suo Shuai Ye Yue Zhao Yonghua Zhu Qi Li Lin Wang Ahn Jihyun Meiling Zhou 《Physica C: Superconductivity and its Applications》2009,469(5-6):230-233
A single Ce0.8Gd0.2O1.9 (CGO) buffer layer was successfully grown on the home-made textured Ni–5 at.%W (Ni–5W) substrates for YBCO coated conductors by a simple metal–organic deposition (MOD) technique. The precursor solution was prepared using a newly developed process and only contained common metal–organic salts of both Ce and Gd dissolved into a propionic acid solvent. The precursor solution at 0.4 M concentration was spin coated on short samples of Ni–5W substrates and heat-treated at 1100 °C in a mixture gas of 5% H2 in Ar for an hour. X-ray studies indicated that the CGO films had good out-of-plane and in-plane textures with full-width-half-maximum values of 4.18° and 6.19°, respectively. Atomic force microscope (AFM) investigations of the CGO films revealed that most of the grain boundary grooves on the Ni–5W surface were found to be well covered by CGO layers, which had a fairly dense and smooth microstructure without cracks and porosity. These results indicate that our MOD technique is very promising for further development of single buffer layer architecture for YBCO coated conductors, due to its low cost and simple process. 相似文献
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M.G. Chourashiya 《Applied Surface Science》2008,254(11):3431-3435
The Gd doped ceria (CGO) in thin layers is of great interest for low temperature operation. In the present investigation, we report on the use of spray pyrolysis technique for the synthesis of CGO thin films. The process parameters were optimized for synthesizing Gd0.1Ce0.9O1.95 films. Films were characterized by XRD, EDS, SEM, and AFM and are observed to be phase pure and dense with surface roughness of the order of ∼5 nm. The d.c. conductivity was also measured and is observed to be ∼0.5 S/cm at 623 K. 相似文献
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K. Rodrigo H.J. WangS. Heiroth N. PrydsL. Theil Kuhn V. EspositoS. Linderoth J. SchouT. Lippert 《Applied Surface Science》2011,257(12):5341-5346
The morphology as well as the spatially resolved elemental and chemical characterization of 10 mol% gadolinia doped ceria (CGO10) structures prepared by pulsed laser deposition (PLD) technique are investigated by scanning transmission electron microscopy accompanied with electron energy loss spectroscopy and energy dispersive X-ray spectroscopy. A dense, columnar and structurally inhomogeneous CGO10 film, i.e. exhibiting grain size refinement across the film thickness, is obtained in the deposition process. The cerium M4,5 edges, used to monitor the local electronic structure of the grains, indicate apparent variation of the ceria valence state across and along the film. No element segregation to the grain boundaries is detected. These results are discussed in the context of solid oxide fuel cell applications. 相似文献
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E. Gourba A. Ringuedé M. Cassir A. Billard J. Päiväsaari J. Niinistö M. Putkonen L. Niinistö 《Ionics》2003,9(1-2):15-20
At the present, a major technological challenge for the development of solid oxide fuel cells (SOFC) is the reduction of their
operation temperature in order to reduce the costs and increase the fuel cell lifetime. Nevertheless, decrease in the operating
temperature leads to losses in cell performance mainly due to the ohmic drop through the electrolyte. Therefore, several approaches
are currently under investigation to overcome the electrolyte problem and the use of oxygen ion conductor thin films seems
to be the most promising solution. In this respect, the well-known electrolyte CeO2-Gd2O3 (CGO) was investigated. Thin layers of less than 5 μm of CGO were deposited using two different techniques: RF magnetron
sputtering and Atomic Layer Deposition (ALD). Physicochemical properties of the thin films obtained were characterised by
X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Furthermore, impedance measurements were carried out in order
to determine the electrical properties of the CGO films, in particular their ionic conductivity.
Paper presented at the 9th EuropConference on Ionics, Ixia, Rhodes, Greece, Sept. 15–21, 2002. 相似文献
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Zeming He Kjeld B?hm Andersen Li Keel Frederik Berg Nygaard Mohan Menon Kent Kammer Hansen 《Ionics》2009,15(4):427-431
In the present work, porous electrode materials lanthanum strontium manganate (LSM)-gadolinium-doped cerium oxide (CGO) and
electrochemical cells LSM-CGO + CGO were fabricated via the processes of slurry preparation, tape casting and lamination,
and sintering. Graphite, wheat starch, and polyamide powders were used as pore formers, respectively, in order to investigate
their effects on shrinkage, flow rate, porosity, and average pore size of the sintered samples. The observation from scanning
electronic microscope (SEM) revealed different microstructures caused by different pore formers. Porous, flat, and crack-free
electrochemical cells were successfully achieved using the present ceramic processing route. The produced cells could potentially
be used for flue gas purification. 相似文献
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V. V. Kharton A. A. Yaremchenko A. P. Viskup F. M. Figueiredo A. L. Shaulo A. V. Kovalevsky E. N. Naumovich F. M. B. Marques 《Ionics》2002,8(3-4):215-222
Modifications of the e.m.f. and faradaic efficiency techniques, taking into account electrode polarization in the measuring
cells, in combination with the use of electrodes having sufficiently high polarization resistances enable a precise determination
of minor electronic contributions to the conductivity of solid electrolytes. These methods were used to determine the p-type
conductivity of compositions based on La(Sr)Ga(Mg)O3-δ (LSGM) and Ce(Gd)O2-δ (CGO) at 900–1270 K. The oxygen ion transference numbers of these materials under oxygen/air gradient vary in the range 0.999–0.970,
increasing with decreasing temperature. Substitution of 2 % gadolinium in Ce0.80Gd0.20O2-δ with praseodymium was found to increase the electron-hole conduction by 2.5 – 4 times. At temperatures above 700 K, both
the partial oxygen ionic and p-type electronic conductivities of LaGaO3-based phases are higher than those in CGO. The electron-hole transport in LSGM tends to increase with the magnesium concentration,
while the activation energy is essentially independent of composition. Electronic conduction in CGO and LSGM electrolytes
was also found to be influenced by the ceramic microstructure.
Paper presented at the 8th EuroConference on Ionics, Carvoeiro, Algarve, Portugal, Sept. 16–22, 2001. 相似文献
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《Solid State Ionics》2006,177(19-25):1843-1848
The electrochemical performance of La0.58Sr0.4Co0.2Fe0.8O3−δ (L58SCF), La0.9Sr1.1FeO4−δ (LS2F) and LSM (La0.65Sr0.3MnO3−δ)/LSM–YSZ (50 wt.% LSM–50 wt.% ZrO2 (8 mol% Y2O3)) cathode electrodes interfaced to a double layer Ce0.8Gd0.2O2−δ (CGO)/YSZ electrolyte was studied in the temperature range of 600 to 850 °C and under flow of 21% O2/He mixture, using impedance spectroscopy and current density–overpotential measurements. The L58SCF cathode exhibited the highest electrocatalytic activity for oxygen reduction, according to the order: LS2F/CGO/YSZ ≤ LSM/LSM–YSZ/CGO/YSZ < L58SCF/CGO/YSZ. 相似文献
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The deposition of gadolinia-doped ceria (CGO, Gd0.1Ce0.9O1.95) and LaGaO3-based perovskite oxides (LSGM, La0.9Sr0.1Ga0.8Mg0.2O2.87) thin films on a stainless steel substrate was studied using the electrostatic spray deposition (EDS) technique. The effect of process conditions, such as deposition temperature, deposition time and liquid flow rate, on the surface morphology and microstructure of thin films was examined with scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The deposited CGO films with a highly porous and three-dimensional interconnected structure were obtained at a liquid flow rate of 0.5 ml/h, a deposition temperature of 503 K and a deposition time ranging from 0.5 to 1 h. On the other hand, the deposited LSGM thin films with porous microstructure were also obtained at the deposition time of 1 h, the deposition temperature of 533 K and the liquid flow rate of 0.5 ml/h. The deposited CGO and LSGM thin films were amorphous at the used deposition temperature. Subsequently, the samples were annealed at 1173 K for 2 h and the desired crystal structures were obtained. The chemical analysis of the thin films was investigated by energy dispersive X-ray (EDX) analysis. The observed chemical compositions of the samples were in a fair agreement with those of the starting solutions. 相似文献
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图像传输和接入要求系统的吞吐量超过Gb/s,若采用常规光码分多址系统来实现图像传输,对光电器件的要求高、实现难度大,解决方案是采用光码分多址并行图像传输系统.针对并行图像传输的签名序列是一种二维光正交签名图形,是一种全新形式的签名码,构造最大容量的光正交签名图形(最佳光正交签名图形)的方法很少这一问题,提出一种区组设计构造算法.算法的思想是根据差集合和光正交码的关系,将差集合和区组设计的概念推广到二维空间,根据二维差集合和光正交签名图形的关系从而构造出最佳光正交签名图形.详细阐述了构造最佳光正交签名图形的步骤,对算法进行了仿真.仿真结果说明该算法可以有效地构造出最佳光正交签名图形. 相似文献