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1.
Jae-Wung Lee Ze Liu Lei Yang Harry Abernathy Song-Ho Choi Hyoun-Ee Kim Meilin Liu 《Journal of power sources》2009,190(2):307-310
Thin films of La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) were deposited on (1 0 0) silicon and on GDC electrolyte substrates by rf-magnetron sputtering using a single-phase oxide target of LSCF. The conditions for sputtering were systematically studied to get dense and uniform films, including substrate temperature (23–600 °C) background pressure (1.2 × 10−2 to 3.0 × 10−2 mbar), power, and deposition time. Results indicate that to produce a dense, uniform, and crack-free LSCF film, the best substrate temperature is 23 °C and the argon pressure is 2.5 × 10−2 mbar. Further, the electrochemical properties of a dense LSCF film were also determined in a cell consisting of a dense LSCF film (as working electrode), a GDC electrolyte membrane, and a porous LSCF counter electrode. Successful fabrication of high quality (dense and uniform) LSCF films with control of thickness, morphology, and crystallinity is vital to fundamental studies of cathode materials for solid oxide fuel cells. 相似文献
2.
A series of cobalt-free and low cost BaCexFe1−xO3−δ (x = 0.15, 0.50, 0.85) materials are successful synthesized and used as the cathode materials for proton-conducting solid oxide fuel cells (SOFCs). The single cell, consisting of a BaZr0.1Ce0.7Y0.2O3−δ (BZCY7)-NiO anode substrate, a BZCY7 anode functional layer, a BZCY7 electrolyte membrane and a BaCexFe1−xO3−δ cathode layer, is assembled and tested from 600 to 700 °C with humidified hydrogen (3% H2O) as the fuel and the static air as the oxidant. Within all the cathode materials above, the cathode BaCe0.5Fe0.5O3−δ shows the highest cell performance which could obtain an open-circuit potential of 0.99 V and a maximum power density of 395 mW cm−2 at 700 °C. The results indicate that the Fe-doped barium cerates can be promising cathodes for proton-conducting SOFCs. 相似文献
3.
Seungho Lee Hwa Seob Song Sang Hoon Hyun Joosun Kim Jooho Moon 《Journal of power sources》2010,195(1):118-123
Core–shell type La0.6Sr0.4Co0.2Fe0.8O3−d (LSCF)–Sm0.2Ce0.8O2−d (SDC) powders are synthesized to achieve a high-performance durable cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The SDC core size is controlled so that all core particles are surrounded by the LSCF particles with no unattached spots. Such a core–shell composite cathode develops an ideal microstructure with improved phase contiguity, homogeneity, and maximized triple-phase boundary density. The cathode that involves an SDC core of 500 nm exhibits the lowest interfacial polarization resistance (0.265 Ω cm2 at 650 °C), as well as long-term stability during both thermo-cyclic and electrochemically accelerated tests. 相似文献
4.
Junliang Li Shaorong Wang Zhenrong Wang Renzhu Liu Tinglian Wen Zhaoyin Wen 《Journal of power sources》2009,194(2):625-630
La0.84Sr0.16MnO3−δ–Bi1.4Er0.6O3 (LSM–ESB) composite cathodes are fabricated by impregnating LSM electronic conducting matrix with the ion-conducting ESB for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The performance of LSM–ESB cathodes is investigated at temperatures below 750 °C by AC impedance spectroscopy. The ion-impregnation of ESB significantly enhances the electrocatalytic activity of the LSM electrodes for the oxygen reduction reactions, and the ion-impregnated LSM–ESB composite cathodes show excellent performance. At 750 °C, the value of the cathode polarization resistance (Rp) is only 0.11 Ω cm2 for an ion-impregnated LSM–ESB cathode, which also shows high stability during a period of 200 h. For the performance testing of single cells, the maximum power density is 0.74 W cm−2 at 700 °C for a cell with the LSM–ESB cathode. The results demonstrate the ion-impregnated LSM–ESB is one of the promising cathode materials for intermediate-temperature solid oxide fuel cells. 相似文献
5.
Bin Lin Mingjun Hu Jianjun Ma Yinzhu Jiang Shanwen Tao Guangyao Meng 《Journal of power sources》2008,183(2):479-484
A stable, easily sintered perovskite oxide BaCe0.5Zr0.3Y0.16Zn0.04O3−δ (BCZYZn) as an electrolyte for protonic ceramic membrane fuel cells (PCMFCs) with Ba0.5Sr0.5Zn0.2Fe0.8O3−δ (BSZF) perovskite cathode was investigated. The BCZYZn perovskite electrolyte synthesized by a modified Pechini method exhibited higher sinterability and reached 97.4% relative density at 1200 °C for 5 h in air, which is about 200 °C lower than that without Zn dopant. By fabricating thin membrane BCZYZn electrolyte (about 30 μm in thickness) on NiO–BCZYZn anode support, PCMFCs were assembled and tested by selecting stable BSZF perovskite cathode. An open-circuit potential of 1.00 V, a maximum power density of 236 mW cm−2, and a low polarization resistance of the electrodes of 0.17 Ω cm2 were achieved at 700 °C. This investigation indicated that proton conducting electrolyte BCZYZn with BSZF perovskite cathode is a promising material system for the next generation solid oxide fuel cells. 相似文献
6.
Chromium-deficient Nd0.75Ca0.25Cr1−xO3−δ (0.02 ≤ x ≤ 0.06) oxides are synthesized and assessed as a novel ceramic interconnect for solid oxide fuel cells (SOFCs). At room temperature, all the samples present single perovskite phase after sintering at 1600 °C for 10 h in air. Cr-deficiency significantly improves the electrical conductivity of Nd0.75Ca0.25Cr1−xO3−δ oxides. No structural transformation occurs in the Nd0.75Ca0.25Cr1−xO3−δ oxides in the temperature range studied. Among all the samples, the Nd0.75Ca0.25Cr0.98O3−δ sample with a relative density of 96.3% exhibits the best electrical conductivity of 39.0 and 1.6 S cm−1 at 850 °C in air and hydrogen, respectively. The thermal expansion coefficient of Nd0.75Ca0.25Cr0.98O3−δ sample is 9.29 × 10−6 K−1 in the temperature range from 30 to 1000 °C in air, which is close to that of 8 mol% yttria stabilized zirconia electrolyte (10.3 × 10−6 K−1) and other cell components. The results indicate that Nd0.75Ca0.25Cr0.98O3−δ is a potential interconnect material for SOFCs. 相似文献
7.
Jung Hyun Kim Yongmin Kim Paul A. Connor John T.S. Irvine Joongmyeon Bae Wuzong Zhou 《Journal of power sources》2009,194(2):704-711
The synthesis, conductivity properties, area specific resistance (ASR) and thermal expansion behaviour of the layered perovskite SmBaCo2O5+d (SBCO) are investigated for use as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The SBCO is prepared and shows the expected orthorhombic pattern. The electrical conductivity of SBCO exhibits a metal–insulator transition at about 200 °C. The maximum conductivity is 570 S cm−1 at 200 °C and its value is higher than 170 S cm−1 over the whole temperature range investigated. Under variable oxygen partial pressure SBCO is found to be a p-type conductor. The ASR of a composite cathode (50 wt% SBCO and 50 wt% Ce0.9Gd0.1O2−d, SBCO:50) on a Ce0.9Gd0.1O2−d (CGO91) electrolyte is 0.05 Ω cm2 at 700 °C. An abrupt increase in thermal expansion is observed in the vicinity of 320 °C and is ascribed to the generation of oxygen vacancies. The coefficients of thermal expansion (CTE) of SBCO is 19.7 and 20.0 × 10−6 K−1 at 600 and 700 °C, respectively. By contrast, CTE values for SBCO:50 are 12.3, 12.5 and 12.7 × 10−6 K−1 at 500, 600 and 700 °C, that is, very similar to the value of the CGO91 electrolyte. 相似文献
8.
Xingbao Zhu Zhe Lü Bo Wei Kongfa Chen Mingliang Liu Xiqiang Huang Wenhui Su 《Journal of power sources》2009,190(2):326-330
The optimization of electrodes for solid oxide fuel cells (SOFCs) has been achieved via a wet impregnation method. Pure La0.75Sr0.25Cr0.5Mn0.5O3−δ (LSCrM) anodes are modified using Ni(NO3)2 and/or Ce(NO3)3/(Sm,Ce)(NO3)x solution. Several yttria-stabilized zirconia (YSZ) electrolyte-supported fuel cells are tested to clarify the contribution of Ni and/or CeO2 to the cell performance. For the cell using pure-LSCrM anodes, the maximum power density (Pmax) at 850 °C is 198 mW cm−2 when dry H2 and air are used as the fuel and oxidant, respectively. When H2 is changed to CH4, the value of Pmax is 32 mW cm−2. After 8.9 wt.% Ni and 5.8 wt.% CeO2 are introduced into the LSCrM anode, the cell exhibits increased values of Pmax 432, 681, 948 and 1135 mW cm−2 at 700, 750, 800 and 850 °C, respectively, with dry H2 as fuel and air as oxidant. When O2 at 50 mL min−1 is used as the oxidant, the value of Pmax increases to 1450 mW cm−2 at 850 °C. When dry CH4 is used as fuel and air as oxidant, the values of Pmax reach 95, 197, 421 and 645 mW cm−2 at 750, 800, 850 and 900 °C, respectively. The introduction of Ni greatly improves the performance of the LSCrM anode but does not cause any carbon deposit. 相似文献
9.
We have developed a Co-free solid oxide fuel cell (SOFC) based upon Fe mixed oxides that gives an extraordinary performance in test-cells with H2 as fuel. As cathode material, the perovskite Sr0.9K0.1FeO3−δ (SKFO) has been selected since it has an excellent ionic and electronic conductivity and long-term stability under oxidizing conditions; the characterization of this material included X-ray diffraction (XRD), thermal analysis, scanning microscopy and conductivity measurements. The electrodes were supported on a 300-μm thick pellet of the electrolyte La0.8Sr0.2Ga0.83Mg0.17O3−δ (LSGM) with Sr2MgMoO6 as the anode and SKFO as the cathode. The test cells gave a maximum power density of 680 mW cm−2 at 800°C and 850 mW cm−2 at 850 °C, with pure H2 as fuel. The electronic conductivity shows a change of regime at T ≈ 350 °C that could correspond to the phase transition from tetragonal to cubic symmetry. The high-temperature regime is characterized by a metallic-like behavior. At 800 °C the crystal structure contains 0.20(1) oxygen vacancies per formula unit randomly distributed over the oxygen sites (if a cubic symmetry is assumed). The presence of disordered vacancies could account, by itself, for the oxide-ion conductivity that is required for the mass transport across the cathode. The result is a competitive cathode material containing no cobalt that meets the target for the intermediate-temperature SOFC. 相似文献
10.
Toshio Suzuki Yoshihiro Funahashi Toshiaki Yamaguchi Yoshinobu Fujishiro Masanobu Awano 《Journal of power sources》2008,183(2):68
Fabrication and characterization of tubular SOFCs under sub-millimeter (0.8 mm), bundles and stacks for low temperature operation were shown. The materials used in this study were Gd doped CeO2 (GDC) for electrolyte, NiO–GDC for anode and (La, Sr)(Co, Fe)O3 (LSCF)–GDC for cathode, respectively, and LSCF for supports of the tubular cells for bundle fabrication. After applying a sealing layer and current collector for each bundle of five micro tubular SOFCs, each bundle was stacked vertically, to build a four-storey cube-type stack with volume of about 0.8 cm3. The performance of the stack was shown to be 3.6 V OCV and 2 W maximum output power under 500 °C operating temperature. Preliminary quick start-up test was also conducted at the condition of 3 min start-up time from 150 to 400 °C for 5 times, and the results showed no degradation of the performance during the test. 相似文献
11.
Lei Zhang Rong Lan Xiaoxiang Xu Shanwen Tao Yinzhu Jiang Arno Kraft 《Journal of power sources》2009,194(2):967-971
A high performance intermediate temperature fuel cell (ITFC) with composite electrolyte composed of co-doped ceria Ce0.8Gd0.05Y0.15O1.9 (GYDC) and a binary carbonate-based (52 mol% Li2CO3/48 mol% Na2CO3), 1.2 mm thick electrolyte layer has been developed. Co-doped Ce0.8Gd0.05Y0.15O1.9 was synthesized by a glycine–nitrate process and used as solid support matrix for the composite electrolyte. The conductivity of both composite electrolyte and GYDC supporting substrate were measured by AC impedance spectroscopy. It showed a sharp conductivity jump at about 500 °C when the carbonates melted. Single cells with thick electrolyte layer were fabricated by a dry-pressing technique using NiO as anode and Ba0.5Sr0.5Co0.8Fe0.2O3−δ or lithiated NiO as cathode. The cell was tested at 450–550 °C using hydrogen as the fuel and air as the oxidant. Excellent performance with high power density of 670 mW cm−2 at 550 °C was achieved for a 1.2 mm thick composite electrolyte containing 40 wt% carbonates which is much higher than that of a cell based on pure GYDC with a 70 μm thick electrolyte layer. 相似文献
12.
Ling Zhao Beibei He Bin Lin Hanping Ding Songlin Wang Yihan Ling Ranran Peng Guangyao Meng Xingqin Liu 《Journal of power sources》2009,194(2):835-837
A dense BaZr0.1Ce0.7Y0.2O3−δ (BZCY) electrolyte is fabricated on a porous anode by in situ drop-coating method which can lead to extremely thin electrolyte membrane (10 μm in thickness). The layered perovskite structure oxide PrBaCo2O5+δ (PBCO) is synthesized by auto ignition process and initially examined as a cathode for proton-conducting IT-SOFCs. The electrical conductivity of PrBaCo2O5+δ (PBCO) reaches the general required value for the electrical conductivity of cathode absolutely. The single cell, consisting of PrBaCo2O5+δ (PBCO)/BaZr0.1Ce0.7Y0.2O3−δ (BZCY)/NiO-BaZr0.1Ce0.7Y0.2O3−δ (BZCY) structure, is assembled and tested from 600 to 700 °C with humidified hydrogen (3% H2O) as the fuel and air as the oxidant. An open-circuit potential of 1.01 V and a maximum power density of 545 mW cm−2 at 700 °C are obtained for the single cell, and a low polarization resistance of the electrodes of 0.15 Ω cm2 is achieved at 700 °C. 相似文献
13.
Cathode materials consisting of Pr1−xSrxCo0.8Fe0.2O3−δ (x = 0.2–0.6) were prepared by the sol–gel process for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The samples had an orthorhombic perovskite structure. The electrical conductivities were all higher than 279 S cm−1. The highest conductivity, 1040 S cm−1, was found at 300 °C for the composition x = 0.4. Symmetrical cathodes made of Pr0.6Sr0.4Co0.8Fe0.2O3−δ (PSCF)–Ce0.85Gd0.15O1.925 (50:50 by weight) composite powders were screen-printed on GDC electrolyte pellets. The area specific resistance value for the PSCF–GDC cathode was as low as 0.046 Ω cm2 at 800 °C. The maximum power densities of a cell using the PSCF–GDC cathode were 520 mW cm−2, 435 mW cm−2 and 303 mW cm−2 at 800 °C, 750 °C and 700 °C, respectively. 相似文献
14.
Xiuquan Gu Liping Zhu Zhizhen Ye Quanbao Ma Haiping He Yinzhu Zhang Binghui Zhao 《Solar Energy Materials & Solar Cells》2008,92(3):343-347
Zn1−xMgxO:Al thin films have been prepared on glass substrates by pulsed laser deposition (PLD). The effect of substrate temperature has been investigated from room temperature to 500 °C by analyzing the structural, optical and electrical properties. The best sample deposited at 250 °C shows the lowest room-temperature resistivity of 5.16×10−4 Ω cm, and optical transmittance higher than 80% in the visible region. It is observed that the optical band gap decreases from 3.92 to 3.68 eV when the substrate temperature increases from 100 to 500 °C. The probable mechanism is discussed. 相似文献
15.
The composite cathode system is examined for suitability on a Ce0.9Gd0.1O2−δ electrolyte based solid oxide fuel cell at intermediate temperatures (500–700 °C). The cathode is characterized for electronic conductivity and area specific charge transfer resistance. This cathode system is chosen for its excellent thermal expansion match to the electrolyte, its relatively high conductivity (115 S cm−1 at 700 °C), and its low activation energy for oxygen reduction (99 kJ mol−1). It is found that the decrease of sintering temperature of the composite cathode system produces a significant decrease in charge transfer resistances to as low as 0.25 Ω cm2. The conductivity of the cathode systems is between 40 and 88 S cm−1 for open porosities of 30–40%. 相似文献
16.
Xiao-Feng Ye S.R. Wang Z.R. Wang Q. Hu X.F. Sun T.L. Wen Z.Y. Wen 《Journal of power sources》2008,183(2):512-517
The perovskite system La1−xSrxCr1−yMyO3−δ (M, Mn, Fe and V) has recently attracted much attention as a candidate material for the fabrication of solid oxide fuel cells (SOFCs) due to its stability in both H2 and CH4 atmospheres at temperatures up to 1000 °C. In this paper, we report the synthesis of La0.75Sr0.25Cr0.5Mn0.5O3 (LSCM) by solid-state reaction and its employment as an alternative anode material for anode-supported SOFCs. Because LSCM shows a greatly decreased electronic conductivity in a reducing atmosphere compared to that in air, we have fabricated Cu-LSCM-ScSZ (scandia-stabilized zirconia) composite anodes by tape-casting and a wet-impregnation method. Additionally, a composite structure (support anode, functional anode and electrolyte) structure with a layer of Cu-LSCM-YSZ (yttria-stabilized zirconia) on the supported anode surface has been manufactured by tape-casting and screen-printing. Single cells with these two kinds of anodes have been fabricated, and their performance characteristics using hydrogen and ethanol have been measured. In the operation period, no obvious carbon deposition was observed when these cells were operated on ethanol. These results demonstrate the stability of LSCM in an ethanol atmosphere and its potential utilization in anode-supported SOFCs. 相似文献
17.
The layered GdBa0.5Sr0.5Co2O5+δ (GBSC) perovskite oxides are synthesized by Pechini method and investigated as a novel cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The single cell of NiO–SDC (Sm0.2Ce0.8O1.9)/SDC (20 μm)/GBSC (10 μm) is operated from 550 to 700 °C fed with humidified H2 as fuel and the static air as oxidant. An open circuit voltage of 0.8 V and a maximum power density of 725 mW cm−2 are achieved at 700 °C. The interfacial polarization resistance is as low as 0.88, 0.29, 0.13 and 0.05 Ω cm2 at 550, 600, 650 and 700 °C, respectively. The ratio of polarization resistance to total cell resistance decreases with the increase in the operating temperature, from 60% at 550 °C to 21% at 700 °C, respectively. The experimental results indicate that GBSC is a promising cathode material for IT-SOFCs. 相似文献
18.
The layered SmBa0.5Sr0.5Co2O5+δ (SBSC) perovskite oxide is synthesized by the Pechini method and investigated as a novel cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). A laboratory-sized Sm0.2Ce0.8O1.9 (SDC)-based tri-layer cell of NiO–SDC/SDC/SBSC is operated from 500 to 700 °C fed with humidified H2 (3% H2O) as a fuel and the static ambient air as oxidant. A maximum power density of 1147 mW cm−2 is achieved at 700 °C. The interfacial polarization resistance is as low as 1.01, 0.38, 0.16, 0.06 and 0.03 Ω cm2 at 500, 550, 600, 650 and 700 °C, respectively. The experimental results indicate that SBSC is a very promising cathode material for IT-SOFCs. 相似文献
19.
Cheng Peng Juri Melnik Jinxia Li Jingli Luo Alan R. Sanger Karl T. Chuang 《Journal of power sources》2009,190(2):447-452
ZnO-doped BaZr0.85Y0.15O3−δ perovskite oxide sintered at 1500 °C has bulk conductivity of the order of 10−2 S cm−1 above 650 °C, which makes it an attractive proton-conducting electrolyte for intermediate-temperature solid oxide fuel cells. The structure, morphology and electrical conductivity of the electrolyte vary with sintering temperature. Optimal electrochemical performance is achieved when the sintering temperature is about 1500 °C. Cathode-supported electrolyte assemblies were prepared using spin coating technique. Thin film electrolytes were shown to be dense using SEM and EDX analyses. 相似文献
20.
Milan Zunic Laure Chevallier Francesca Deganello Alessandra DEpifanio Silvia Licoccia Elisabetta Di Bartolomeo Enrico Traversa 《Journal of power sources》2009,190(2):417-422
Proton conducting BaCe0.9Y0.1O3−x (BCY10) thick films are deposited on cermet anodes made of nickel–yttrium doped barium cerate using electrophoretic deposition (EPD) technique. BCY10 powders are prepared by the citrate–nitrate auto-combustion method and the cermet anodes are prepared by the evaporation and decomposition solution and suspension method. The EPD parameters are optimized and the deposition time is varied between 1 and 5 min to obtain films with different thicknesses. The anode substrates and electrolyte films are co-sintered at 1550 °C for 2 h to obtain a dense electrolyte film keeping a suitable porosity in the anode, with a single heating treatment. The samples are characterized by field emission scanning electron microscopy (FE-SEM) and energy dispersion spectroscopy (EDS). A prototype fuel cell is prepared depositing a composite La0.8Sr0.2Co0.8Fe0.2O3 (LSCF)–BaCe0.9Yb0.1O3−δ (10YbBC) cathode on the co-sintered half cell. Fuel cell tests that are performed at 650 °C on the prototype single cells show a maximum power density of 174 mW cm−2. 相似文献