共查询到20条相似文献,搜索用时 15 毫秒
1.
Guoqiang Cai Renzhu Liu Chunhua Zhao Junliang Li Shaorong Wang Tinglian Wen 《Journal of Solid State Electrochemistry》2011,15(1):147-152
The 70 wt.% Mn-doped CeO2 (MDC)-30 wt.% Scandia-stabilized zirconia (ScSZ) composites are evaluated as anode materials for solid oxide fuel cells (SOFCs)
in terms of chemical compatibility, thermal expansion coefficient, electrical conductivity, and fuel cell performance in H2 and CH4. The conductivity of MDC10 (10 mol.% Mn-doping), MDC20, and CeO2 are 4.12, 2.70, and 1.94 S cm−1 in H2 at 900 °C. With 10 mol.% Mn-doping, the fuel cells performances improve from 166 to 318 mW cm−2 in H2 at 900 °C. The cell with MDC10–ScSZ anode exhibits a better performance than the one with MDC20–ScSZ in CH4, the maximum power density increases from 179 to 262 mW cm−2. Electrochemical impedance spectra indicate that the Mn doping into CeO2 can reduce the ohmic and polarization resistance, thus leading to a higher performance. The results demonstrate the potential
ability of MDC10–ScSZ composite to be used as SOFCs anode. 相似文献
2.
Improvement of long-term stability of 40vol.%NiO–60vol.% yttria-stabilized zirconia (YSZ) anode material in reducing atmosphere
and under exposure to thermal shock through the modification of vacancy concentration and pore shape has been investigated
for a solid oxide fuel cell. We varied the amount of Y2O3 additives from 8 to 10 mol% in YSZ and the type of carbon pore former, from plated activated carbon to spherical carbon black,
to improve the strength and the stability of porous NiO–YSZ anode materials. Modifications by varying the amount of Y2O3 additives and carbon pore former result in a highly stable anode, even upon exposure to a reducing atmosphere for 1,200 h.
In particular, the strengths of the new anode materials are markedly improved at the same porosity level. Higher strengths
do not degrade during a longtime durability test in a reducing atmosphere or upon thermal shock testing. The relatively smaller
degradation of electrical conductivity of the new anode material is discussed in terms of the possibility of suppression of
the disconnectivity of Ni phases during operation of a solid oxide fuel cell. 相似文献
3.
W. K. Yoshito J. R. Matos V. Ussui D. R. R. Lazar J. O. A. Paschoal 《Journal of Thermal Analysis and Calorimetry》2009,97(1):303-308
A porous nickel–8 mol% yttria stabilized zirconia (Ni–8YSZ) composite, used as anode for solid oxide fuel cell, was obtained
by reduction of NiO–8YSZ cermet. The first goal was the evaluation of the temperature effect of powder processing by thermogravimetry.
In addition, the influence of porosity in the reduction kinetic of the sample sintered at 1450 °C was evaluated. The final
porosity produced in NiO–8YSZ composite by pore former was 30.4 and 37.9 vol.%, respectively, for 10 and 15 mass% of corn
starch. The sample with 15 mass% of corn starch promotes a reduction rate almost twice higher than sample with 10 mass% of
corn starch. The porosity introduced by the reduction of NiO was 23 vol.%. 相似文献
4.
The Nd2???x Sr x NiO4?+?δ (x?=?0.1–0.5) solid solutions prepared by combustion synthesis are of submicron/superfine crystallite size. The crystal structure estimated by Rietveld analysis reveals increase in space in the rock salt layer on partial replacement of Nd3+ by Sr2+. The transition from negative temperature coefficient to positive temperature coefficient of conductivity is observed at 913 K. The maximum dc conductivity (σ?=?1.3?±?0.02 S?cm?1 at 973 K) is obtained for x?=?0.2 in Nd2???x Sr x NiO4?+?δ . The low dc conductivity compared with reported (≈100 S?cm?1) is due to high porosity (low relative density) resulting from agglomeration of submicron crystallites. The variation in the conductivity with Sr content in Nd2???x Sr x NiO4?+?δ is understood on the basis of defect chemistry. The electrochemical properties of the cathode materials are studied using electrochemical impedance spectroscopy at various temperatures and oxygen partial pressures. Nd1.8Sr0.2NiO4?+?δ cathode exhibits lowest-area-specific resistance?=?0.52?±?0.015 Ohm?cm2 at 973 K. At low $ {P_{{{{{\bf O}}_2}}}} $ (<1,000 Pa), oxygen ion transfer from Nd1.8Sr0.2NiO4?+?δ cathode to gadolinium-doped ceria electrolyte is the rate-limiting step, whereas, charge-transfer reaction on the cathode becomes more important at high oxygen partial pressures and temperature (973 K). 相似文献
5.
A technique for formation of electrolyte thin films with the thickness of 6–10 μm of zirconia stabilized by yttria (YSZ) is
developed on the basis of the method of chemical deposition from the vapor phase of organometallic compounds (MOCVD). Planar
electrochemical cells based on film electrolyte with a supporting anode with the working surface area of 12 cm2 were manufactured. A solid-oxide fuel cell (SOFC) based on two fuel cells was developed and its life cycle tests at reduced
operating temperatures (<800°C) were carried out for 400 h. The maximum power density reached in the SOFC tests was 316 mW/cm2. 相似文献
6.
D. A. Krainova S. T. Zharkinova N. S. Saetova A. A. Raskovalov A. V. Kuz’min V. A. Eremin E. A. Sherstobitova S. V. Pershina M. V. Dyadenko Xiaoa Zhang Shengling Jiang 《Russian Journal of Applied Chemistry》2017,90(8):1278-1284
The influence of the cerium oxide concentration on the properties of glasses and glass ceramics of the SiO2–Al2O3–CaO–Na2O–MgO–K2O–B2O3–CeO2 system as potential adhesive and sealing materials for solid oxide fuel cells was studied. According to the data of differential scanning calorimetry, variation of the CeO2 concentration does not appreciably influence the glass transition and crystallization temperatures of glasses. As the cerium oxide concentration is increased, the linear thermal expansion coefficient increases for the glasses but decreases for the partially crystalline samples. The gluing temperature of the glass sealants prepared allows their use for joining YSZ solid electrolytes with interconnectors of Crofer22APU type in solid oxide fuel cells.. 相似文献
7.
《Electrochemistry communications》2008,10(2):302-305
Recently, extensive studies on the ceria-based two-phase composites as functional electrolytes have created excellent 300–600 °C fuel cell technology. There is an emergence need to deepen the knowledge and to develop theoretical methodologies in this field. The feasibility to design and develop two-phase materials as superionic conductors for 300–600 °C solid oxide fuel cells (LTSOFCs) is reported. The superionic conductivity at 300–600 °C in two-phase materials where the interfaces between the constituent phases are constructed as “superionic highways” resulting in interfacial high ionic conduction. The material architecture and design presented in this report thus reaches beyond the conventional molecular way to synthesize new compounds. 相似文献
8.
E. Arico F. Tabuti F. C. Fonseca D. Z. de Florio A. S. Ferlauto 《Journal of Thermal Analysis and Calorimetry》2009,97(1):157-161
The thermal behavior of the yttria-stabilized zirconia (YSZ) and nickel oxide (YSZ–NiO) composite mixtures with the addition
of graphite, multiwall carbon nanotubes and functionalized multiwall carbon nanotubes was studied. The YSZ–NiO composite is
the precursor of the YSZ–Ni anode of solid oxide fuel cells. The anode exhibits a porous structure, which is usually obtained
by the addition of carbon containing pore formers. Thermal analysis and X-ray diffraction evidenced that the properties of
carbonaceous materials (C) and atmosphere have a strong influence on the thermal evolution of the reactions taking place upon
heating the anode precursor. The dependence of both the carbon content and the chemical nature of the ceramic matrix on the
thermal behavior of the composite were investigated. The discussed results evidenced important features for optimized processing
of the anode. 相似文献
9.
In recent decades, high-temperature oxygen reduction reaction on mixed conducting cathodes were investigated intensively by many researchers. Computational approaches as well as electrochemical and spectroscopic studies have been made to elucidate the kinetics. Contribution of oxygen vacancy to the reaction rate was suggested in multiple reports, and plausible reaction pathways were proposed based on density functional theory (DFT) calculations. The picture of oxygen reduction reaction has become clearer in these years. However, there still is a discussion about a credible formula that represents the current–voltage relationships. Discrepancies are found among the reported data on the magnitude of the rate constant and on its dependencies on partial pressure and temperature. The difference is significant between a model electrode and a practical porous electrode. Comparison of the results suggests the existence of series reaction barriers, that is, the surface reaction and subsurface transport, which should be considered for consistent representation of the total electrode process. 相似文献
10.
I. N. Burmistrov D. A. Agarkov E. V. Korovkin D. V. Yalovenko S. I. Bredikhin 《Russian Journal of Electrochemistry》2017,53(8):873-879
The results on optimizing the procedure of preparation of the electrode system within membrane–electrode assemblies (MEA) of solid-oxide fuel cells (SOFC) by joint sintering of electrodes at the enhanced temperature close to that of anode sintering are presented. The MEA are prepared based on membranes of the anionic conductor HionicTM (Fuel Cell Materials, USA); the cathode is formed based on cation–deficient lanthanum-strontium manganite (La0.8Sr0.2)0.95MnO3 with addition of activated carbon for optimizing its microstructure; the anode is formed on the basis of cermet NiO/10Sc1CeSZ (89 mol % ZrO2, 10 mol % Sc2O3, 1 mol % CeO2). The results of electrochemical testing of model MEA are also shown. 相似文献
11.
Motivated by recent work on the Ruddlesden–Popper material, which was shown to be a superior oxide-ion conductor than conventional solid-oxide fuel cell cathode perovskite materials,
we undertook A- and B-site doping studies of the Ruddlesden–Popper nickelate series in an attempt to identify other candidates
for cathode application. In this paper, we summarize our most significant results for the and systems and more recently, the higher-order Ruddlesden–Popper phases La
n+1Ni
n
O3n+1 (n=2 and 3), which show greater promise as cathode materials than the n=1 compositions. 相似文献
12.
Very high electrical conductivity of ~0.021 S/cm at 600 °C is obtained in Ce0.79Gd0.20Co0.01O2?δ. Corresponding activation energy of conduction ~0.43 eV measured in the temperature range of 400–700 °C is found to be notably low. Improved electrical properties with 99% of the theoretical density as obtained for these specimens, prepared using powder of average particle size ~20 nm and subsequent sintering at 1100 °C, is considered to be a significant step to reduce the processing temperature. The measured electrical potential of ~1 V indicates the suitability of its use as an electrolyte in electrochemical devices. 相似文献
13.
Makiko Asamoto Shinji Miyake Kazunari Sugihara Hidenori Yahiro 《Electrochemistry communications》2009,11(7):1508-1511
The anodic performances of Ni/CeO2–Sm2O3(Ni/SDC) modified by the addition of alkaline earth metal oxides (MgO, CaO, and SrO) were investigated for direct oxidation of CH4 in solid oxide fuel cells (SOFCs). Although the initial power density of cell with Ni/SDC anode modified by the addition of CaO was slightly lower than that of cell with Ni/SDC, the former anode exhibited an excellent stability compared to the latter one. Such a high stability of Ni–CaO/SDC anode may come from the inhibition of carbon deposition in addition to the retained ionic conductivity of anode. 相似文献
14.
《Annales de Chimie Science des Materiaux》2001,26(4):49-58
The development of solid oxide fuel cells (SOFC) offers new perspectives, in particular as auxiliary power units for vehicle applications. The elaboration of thin electrolyte layers is the main challenge in order to reduce their operating temperature. A brief review of the deposition techniques and of the potential electrolytes is presented. A relatively new technique, Atomic Layer Deposition (ALD), allows to produce thin, dense and homogeneous layers, i.e. zirconia or zirconia-based thin layers can be deposited on different substrates. The interest of elaborating bi- or multi-layer electrolytes is outlined. 相似文献
15.
Chengjun Zhu Xiaomei Liu Cuishan Yi Li Pei Duanting Yan Jiangpo Niu Dejun Wang Wenhui Su 《Electrochemistry communications》2009,11(5):958-961
The BaCo0.7Fe0.3?yNbyO3?δ oxides (BCFNy, y = 0.00–0.12) were synthesized by the conventional solid state reaction process and investigated as a novel cathode for intermediate temperature solid oxide fuel cells(IT-SOFCs). Cubic perovskite, with enhanced phase stability at higher Nb concentration, was obtained at y ? 0.04. The unit cell volumes increased with y, reached a maximum at y = 0.10, and then decreased. The niobium doping concentration also had a significant effect on the electrochemical performance of BCFNy materials. Among the various BCFNy oxides tested, BCFN0.10 possessed the smallest interfacial polarization resistance (Rp). The Rp was as low as 0.9406, 0.1300, 0.0211, and 0.0082 Ω cm2 at 500, 600, 700, and 800 °C, respectively. With a 220 μm-thick Sm0.2Ce0.1O1.9 (SDC) as electrolyte and BCFN0.10 as the cathode, a fuel cell provides maximum power densities of 202, 350, 569, 820, and 1006 mW cm?2 at 600, 650, 700, 750, and 800 °C, respectively. The encouraging results suggested that BCFN0.10 was a very promising cathode material for IT-SOFCs. 相似文献
16.
Sr doped LaMnO(3) is a perovskite widely used for solid oxide fuel cell (SOFC) cathodes. Therefore, there is significant interest in its defect chemistry. However, due to coupling of defect reactions and inadequate constraints of the defect reaction equilibrium constants obtained from thermogravimetry analysis, large discrepancies (up to 4 eV) exist in the literature for defect energetics for Sr doped LaMnO(3). In this work we demonstrate how ab initio energetics and empirical modelling can be combined to develop a defect model for LaMnO(3). Defect formation enthalpies, including concentration dependence due to defect interactions, are extracted from ab initio energies calculated at various defect concentrations. Defect formation entropies for the defect reactions in LaMnO(3) involving O(2-)(solid) ? ?O(2)(gas) + 2e(-) are shown to be accessible through combining the gas phase thermodynamics and simple models for the solid phase vibrational contributions. This simple treatment introduces a useful constraint on fitting defect formation entropies. The predicted defect concentrations from the model show good agreement with experimental oxygen nonstoichiometry vs. P(O(2)) for a wide range of temperatures (T = 873-1473 K), suggesting the effectiveness of the ab initio defect energetics in describing the defect chemistry of LaMnO(3). Further incorporating a temperature dependent charge disproportionation energy within 0.0-0.2 eV, the model is capable of describing both defect chemistry and oxygen tracer diffusivity of LaMnO(3). The model suggests an important role for defect interactions which are typically excluded from LaMnO(3) defect models, and sensitivity of the oxygen defect concentration to the charge disproportionation energy in the high P(O(2)) region. Similar approaches to those used here can be used to model the defect chemistry for other complex oxides. 相似文献
17.
Shakouri Omolbanin Assad Mamdouh El Haj Açıkkalp Emin 《Journal of Thermal Analysis and Calorimetry》2021,145(3):1075-1090
Journal of Thermal Analysis and Calorimetry - This paper targets to consider a hybrid cycle consisting of a solid oxide fuel cell and an Ericsson thermal engine that provides drinking water by... 相似文献
18.
Redox cycling of Ni-based anode induces cell degradation which limits the cell's lifetime during solid oxide fuel cell operation. In the present study, the redox testing of electrolyte-supported cells has been investigated with TiO2-added NiO–YSZ anode matrix. Button cells were fabricated by die-pressing YSZ powder as electrolyte, and onto which NiO–YSZ or NiO–TiO2–YSZ anode and LSM–YSZ composite cathode were painted. The electrochemical performance and stability have been evaluated by measuring current–voltage characteristics followed by impedance spectroscopy after each redox cycling. Anode matrices before and after cell operation have been characterized by X-ray diffraction (XRD), elemental dispersive X-ray (EDX), and scanning electron microscopy (SEM). During cell operation the peak power density decreases from 111 mW cm?2 (239 mA cm?2) to 84 mW cm?2 (188 mA cm?2) between 23 and 128 h with five redox cycles for cell having NiO–YSZ (40:60) anode. But for cell with NiO–TiO2–YSZ (30:10:60), the anode peak power density was constant and stable around 85 mW cm?2 (194 mA cm?2) throughout the cell run of 130 h and five redox cycles. No loss in the open circuit voltage was observed. SEM and XRD studies of NiO–TiO2–YSZ (30:10:60) anodes revealed formation of ZrTiO4, which may be responsible for inhibition of Ni coarsening leading to stable cell performance. 相似文献
19.
《Journal of membrane science》2001,185(1):73-81
The availability of stable polymeric membranes with good proton conductivity at medium temperatures is very important for the development of methanol PEM fuel cells. In view of this application, a systematic investigation of the conductivity of Nafion 117 and sulfonated polyether ether ketone (S-PEEK) membranes was performed as a function of relative humidity (r.h.) in a wide range of temperature (80–160°C). The occurrence of swelling/softening phenomena at high r.h. values prevented conductivity determinations above certain temperatures. Nevertheless, when r.h. was maintained at values lower than 80%, measurements were possible up to 160°C. The results showed that Nafion is a better proton conductor than S-PEEK at low r.h. values, especially at temperatures lower than 120°C. The differences in conductivity were, however, leveled out with the increasing r.h. and temperature. While at 100°C and 35% r.h. the conductivity of S-PEEK 2.48 was about 30 times lower than the conductivity of Nafion, both membranes reached a comparable conductivity (4×10−2 S cm−1) at 160°C and 75% r.h. The effect of superacidity and crystallization of the polymers on the conductivity, as well as the possibility of using Nafion and S-PEEK membranes in medium temperature fuel cells, are discussed. 相似文献
20.
Vaibhav Vibhu Aurélien Flura Aline Rougier Clément Nicollet Sébastien Fourcade Teresa Hungria Jean-Claude Grenier Jean-Marc Bassat 《Journal of Energy Chemistry》2020,(7):62-70,I0003
The chemical and electrochemical stability of lanthanide nickelates La2 NiO4+δ(LNO),Pr2 NiO4+δ(PNO)and their mixed compounds La(2-x)PrxNiO4+δ(LPNOs)with x=0.5,1 or 1.5 is reported.The aim is to promote these materials as efficient electrodes for solid oxide fuel cell(SOFC)and/or solid oxide electrolysis cell(SOEC).La2 NiO4+δand La1.5Pr0.5NiO4+δcompounds are chemically very stable as powders over one month in the temperature range 600-800℃,while the other materials rich in praseodymium progressively decompose into various perovskite-deriving components with additional Pr6 O11.Despite their uneven properties,all these materials are quite efficient and sustainable as electrodes on top of gadolinium doped ceria(GDCBL)//yttrium doped zirconia(8 YSZ)electrolyte,for one month at 700℃without polarization.Under polarization(300 mA·cm-2),the electrochemical performances of LNO,PNO and La1.5Pr0.5NiO4+δ(LP5 NO)quickly degrade in SOFC mode,i.e.for the oxygen reduction reaction,while they show durability in SOEC mode,i.e.for the oxide oxidation reaction. 相似文献