共查询到20条相似文献,搜索用时 31 毫秒
1.
Wei Zhou Zongping ShaoRan Ran Pingying ZengHongxia Gu Wanqin JinNanping Xu 《Journal of power sources》2007
A novel Ba0.5Sr0.5Co0.8Fe0.2O3 − δ + LaCoO3 (BSCF + LC) composite oxide was investigated for the potential application as a cathode for intermediate-temperature solid-oxide fuel cells based on a Sm0.2Ce0.8O1.9 (SDC) electrolyte. The LC oxide was added to BSCF cathode in order to improve its electrical conductivity. X-ray diffraction examination demonstrated that the solid-state reaction between LC and BSCF phases occurred at temperatures above 950 °C and formed the final product with the composition: La0.316Ba0.342Sr0.342Co0.863Fe0.137O3 − δ at 1100 °C. The inter-diffusion between BSCF and LC was identified by the environmental scanning electron microscopy and energy dispersive X-ray examination. The electrical conductivity of the BSCF + LC composite oxide increased with increasing calcination temperature, and reached a maximum value of ∼300 S cm−1 at a calcination temperature of 1050 °C, while the electrical conductivity of the pure BSCF was only ∼40 S cm−1. The improved conductivity resulted in attractive cathode performance. An area-specific resistance as low as 0.21 Ω cm2 was achieved at 600 °C for the BSCF (70 vol.%) + LC (30 vol.%) composite cathode calcined at 950 °C for 5 h. Peak power densities as high as ∼700 mW cm−2 at 650 °C and ∼525 mW cm−2 at 600 °C were reached for the thin-film fuel cells with the optimized cathode composition and calcination temperatures. 相似文献
2.
This study presents the electrochemical performance of (Ba0.5Sr0.5)0.9Sm0.1Co0.8Fe0.2O3−δ (BSSCF) as a cathode material for intermediate temperature solid oxide fuel cells (IT-SOFC). AC-impedance analyses were carried on an electrolyte supported BSSCF/Sm0.2Ce0.8O1.9 (SDC)/Ag half-cell and a Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF)/SDC/Ag half-cell. In contrast to the BSCF cathode half-cell, the total resistance of the BSSCF cathode half-cell was lower, e.g., at 550 °C; the values for the BSSCF and BSCF were 1.54 and 2.33 Ω cm2, respectively. The cell performance measurements were conducted on a Ni-SDC anode supported single cell using a SDC thin film as electrolyte, and BSSCF layer as cathode. The maximum power densities were 681 mW cm−2 at 600 °C and 820 mW cm−2 at 650 °C. 相似文献
3.
Hongxia Gu Ran Ran Wei Zhou Zongping Shao Wanqin Jin Nanping Xu Jeongmin Ahn 《Journal of power sources》2008
Hydrazine was examined as a fuel for a solid-oxide fuel cell (SOFC) that employed a typical nickel-based anode. An in situ catalytic decomposition of hydrazine at liquid state under room temperature and ambient pressure before introducing to the fuel cell was developed by applying a Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) oxide catalyst. Catalytic testing demonstrated that liquid N2H4 can be decomposed to gaseous NH3 and H2 at a favorable rate and at a temperature as low as 20 °C and H2 selectivity reaching values as high as 10% at 60 °C. Comparable fuel cell performance was observed using either the in situ decomposition products of hydrazine or pure hydrogen as fuel. A peak power density of ∼850 mW cm−2 at 900 °C was obtained with a typical fuel cell composed of scandia-stabilized zirconia and La0.8Sr0.2MnO3 cathode. The high energy and power density, easy storage and simplicity in fuel delivery make it highly attractive for portable applications. 相似文献
4.
Bin Lin Hanping Ding Yingchao DongSonglin Wang Xiaozhen ZhangDaru Fang Guangyao Meng 《Journal of power sources》2009
The perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3-δ–BaZr0.1Ce0.7Y0.2O3-δ (BSCF–BZCY) composite oxides were synthesized by a modified Pechini method and examined as a novel composite cathode for intermediate-to-low temperature protonic ceramic membrane fuel cells (ILT-PCMFCs). Thin proton-conducting BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte and NiO–BaZr0.1Ce0.7Y0.2O3-δ (NiO–BZCY) anode functional layer were prepared over porous anode substrates composed of NiO–BaZr0.1Ce0.7Y0.2O3-δ by a one-step dry-pressing/co-firing process. A laboratory-sized quad-layer cell of NiO–BZCY/NiO–BZCY(∼50 μm)/BZCY(∼20 μm)/BSCF–BZCY(∼50 μm) was operated from 550 to 700 °C with humidified hydrogen (∼3% H2O) as fuel and the static air as oxidant. A high open-circuit potential of 1.009 V, a maximum power density of 418 mW cm−2, and a low polarization resistance of the electrodes of 0.10 Ω cm2 was achieved at 700 °C. These investigations have indicated that proton-conducting BZCY electrolyte with BSCF perovskite cathode is a promising material system for the next generation solid oxide fuel cells (SOFCs). 相似文献
5.
A nickel-based anode-supported solid oxide fuel cell (SOFC) was assembled with a 10 μm thick Ce0.8Sm0.2O2−δ (SDC) electrolyte and a Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) cathode. The cell performance was investigated with hydrogen and ammonia gas evaporated from liquefied ammonia as fuel. Fueled by hydrogen the maximum power densities were 1872, 1357, and 748 mW cm−2 at 650, 600, and 550 °C, respectively. While with ammonia as fuel, the cell showed the maximum power densities of 1190, 434, and 167 mW cm−2, correspondingly. The power densities lower than that predicted, particularly at the lower operating temperatures for ammonia fuel cell, compared to hydrogen fuel cell, could be attributed to actual lower temperature than thermocouple display due to endothermic reaction of ammonia decomposition as well as the rather larger inlet ammonia flow rate. The results demonstrated that the ammonia was a right convenient liquid fuel for SOFCs as long as it was keeping the decomposition completion of ammonia in the cell or before entering the cell. 相似文献
6.
A no-chamber solid-oxide fuel cell operated on a fuel-rich ethanol flame was reported. Heat produced from the combustion of ethanol thermally sustained the fuel cell at a temperature of 500–830 °C. Considerable amounts of hydrogen and carbon monoxide were also produced during the fuel-rich combustion which provided the direct fuels for the fuel cell. The location of the fuel cell with respect to the flame was found to have a significant effect on the fuel cell temperature and performance. The highest power density was achieved when the anode was exposed to the inner flame. By modifying the Ni + Sm0.2Ce0.8O1.9 (SDC) anode with a thin Ru/SDC catalytic layer, the fuel cell envisaged not only an increase of the peak power density to ∼200 mW cm−2 but also a significant improvement of the anodic coking resistance. 相似文献
7.
The properties and performance of Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) + Sm0.2Ce0.8O1.9 (SDC) (70:30 in weight ratio) composite cathode for intermediate-temperature solid-oxide fuel cells were investigated. Mechanical mixing of BSCF with SDC resulted in the adhesion of fine SDC particles to the surface of coarse BSCF grains. XRD, SEM-EDX and O2-TPD results demonstrated that the phase reaction between BSCF and SDC was negligible, constricted only at the BSCF and SDC interface, and throughout the entire cathode with the formation of new (Ba,Sr,Sm,Ce)(Co,Fe)O3−δ perovskite phase at a firing temperature of 900, 1000, and ≥ 1050 °C, respectively. The BSCF + SDC electrode sintered at 1000 °C showed an area specific resistance of ∼0.064 Ω cm2 at 600 °C, which is a slight improvement over the BSCF (0.099 Ω cm2) owing to the enlarged cathode surface area contributed from the fine SDC particles. A peak power density of 1050 and ∼382 mW cm−2 was reached at 600 and 500 °C, respectively, for a thin-film electrolyte cell with the BSCF + SDC cathode fired from 1000 °C. 相似文献
8.
Wenping Sun 《Journal of power sources》2010,195(10):3155-9355
A Sm0.5Sr0.5CoO3−δ-Ce0.8Sm0.2O2−δ (SSC-SDC) composite is employed as a cathode for proton-conducting solid oxide fuel cells (H-SOFCs). BaZr0.1Ce0.7Y0.2O3−δ (BZCY) is used as the electrolyte, and the system exhibits a relatively high performance. An extremely low electrode polarization resistance of 0.066 Ω cm2 is achieved at 700 °C. The maximum power densities are: 665, 504, 344, 214, and 118 mW cm−2 at 700, 650, 600, 550, and 500 °C, respectively. Moreover, the SSC-SDC cathode shows an essentially stable performance for 25 h at 600 °C with a constant output voltage of 0.5 V. This excellent performance implies that SSC-SDC, which is a typical cathode material for SOFCs based on oxide ionic conductor, is also a promising alternative cathode for H-SOFCs. 相似文献
9.
Composite materials of Sm0.2Ce0.8O1.9 (SDC) with various Ni–Fe alloys were synthesized and evaluated as the anode for intermediate temperature solid oxide fuel cell. The performance of single cells consisting of the Ni–Fe + SDC anode, SDC buffer layer, La0.8Sr0.2Ga0.83Mg0.17O2.815 (LSGM) electrolyte, and SrCo0.8Fe0.2O3 − δ (SCF) cathode were measured in the temperature range of 600–800 °C with wet H2 as fuel. It was found that the anodic overpotentials of the different Fe–Ni compositions at 800 °C were in the following order: Ni0.8Fe0.2 < Ni0.75Fe0.25 < Ni < Ni0.7Fe0.3 < Ni0.9Fe0.1 < Ni0.95Fe0.05 < Ni0.33Fe0.67. The single cell with the Ni0.8Fe0.2 + SDC anode exhibited a maximum power density of 1.43 W cm−2 at 800 °C and 0.62 W cm−2 at 700 °C. The polarization resistance of the Ni0.8Fe0.2 + SDC anode was as low as 0.105 Ω cm2 at 800 °C under open circuit condition. A stable performance with essentially negligible increase in anode overpotential was observed during about 160 h operation of the cell with the Ni0.8Fe0.2 + SDC anode at 800 °C with a fixed current density of 1875 mA cm−2. The possible mechanism responsible for the improved electrochemical properties of the composite anodes with the Ni0.8Fe0.2 and Ni075Fe0.25 alloys was discussed. 相似文献
10.
PrBaCo2O5+δ (PBCO) powder was prepared by a combined EDTA and citrate complexing method. The electrochemical performance of PBCO as a cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs) was evaluated. A porous layer of PBCO was deposited on a 42 μm thick electrolyte consisting of Ce0.8Sm0.2O1.9 (SDC), prepared by a dry-pressing process. A fuel cell with a structure PBCO/SDC/Ni-SDC provides a maximum power density of 866, 583, 313 and 115 mW cm−2 at 650, 600, 550 and 500 °C, respectively, using hydrogen as the fuel and stationary air as the oxidant. The total resistance of the cell was about 0.41, 0.51, 0.57 and 0.77 Ω cm2, respectively. This encouraging data identifies PBCO as a potential cathode material for IT-SOFCs. 相似文献
11.
A polyvinyl alcohol assisted combustion synthesis method was used to prepare Ce0.8Sm0.2O2−δ (SDC) powders for an intermediate temperature solid oxide fuel cell (IT-SOFC). The XRD results showed that this combustion synthesis route could yield phase-pure SDC powders at a relatively low calcination temperature. A thin SDC electrolyte film with thickness control was produced by a dry pressing method at a lower sintering temperature of 1250 °C. With Sm0.5Sr0.5Co3-SDC as the composite cathode, a single cell based on this thin SDC electrolyte was tested from 550 to 650 °C. The maximum power density of 936 mW cm−2 was achieved at 650 °C using humidified hydrogen as the fuel and stationary air as the oxidant. 相似文献
12.
Mingfei Liu Dehua Dong Fei Zhao Jianfeng Gao Dong Ding Xingqin Liu Guangyao Meng 《Journal of power sources》2008
Cathode-supported solid oxide fuel cells (SOFCs), comprising porous Pr0.35Nd0.35Sr0.3MnO3−δ (PNSM)/Sm0.2Ce0.8O1.95 (SDC) cathode supports, SDC function layers, YSZ electrolyte membranes and NiO/SDC anode layers, were successfully fabricated via suspensions coating and single-step co-firing process. The microstructures of electrolyte membranes were observed with scanning electron microscope (SEM). The assembled single cell was electrochemically characterized with humidified hydrogen as fuel and ambient air as oxidant. The open circuit voltage (OCV) of the cell was 1.036 V at 650 °C, and the peak power densities were 657, 472, 290 and 166 mW cm−2 at 800, 750, 700 and 650 °C, respectively. Impedance analysis indicated that the performance of cathode-supported cell was determined essentially by electrode polarization resistance, which suggested that optimizing electrodes was especially important for improving the cell performance. 相似文献
13.
SmBaCo2O5+x (SBCO), an oxide with double-perovskite structure, has been developed as a novel cathode material for intermediate-temperature solid-oxide fuel cells (IT-SOFCs). The electrical conductivity of an SBCO sample reaches 815–434 S cm−1 in the temperature range 500–800 °C. XRD results show that an SBCO cathode is chemically compatible with the intermediate-temperature electrolyte materials Sm0.2Ce0.8O1.9 (SDC) and La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM). The polarization resistances of an SBCO cathode on SDC and LSGM electrolytes are 0.098 and 0.054 Ω cm2 at 750 °C, respectively. The maximum power densities of a single cell with an SBCO cathode on SDC and LSGM electrolytes reach 641 and 777 mW cm−2 at 800 °C, respectively. The results of this study demonstrate that the double-perovskite structure oxide SBCO is a very promising cathode material for use in IT-SOFCs. 相似文献
14.
Zhan Gao Jianbing HuangZongqiang Mao Cheng WangZhixiang Liu 《International Journal of Hydrogen Energy》2010
Nanocrystalline Ce0.8Sm0.2O1.9 (SDC) has been synthesized by a combined EDTA–citrate complexing sol–gel process for low temperature solid oxide fuel cells (SOFCs) based on composite electrolyte. A range of techniques including X-ray diffraction (XRD), and electron microscopy (SEM and TEM) have been employed to characterize the SDC and the composite electrolyte. The influence of pH values and citric acid-to-metal ions ratios (C/M) on lattice constant, crystallite size and conductivity has been investigated. Composite electrolyte consisting of SDC derived from different synthesis conditions and binary carbonates (Li2CO3–Na2CO3) has been prepared and conduction mechanism is discussed. Water was observed on both anode and cathode side during the fuel cell operation, indicating the composite electrolyte is co-ionic conductor possessing H+ and O2− conduction. The variation of composite electrolyte conductivity and fuel cell power output with different synthesis conditions was in accordance with that of the SDC originated from different precursors, demonstrating O2− conduction is predominant in the conduction process. A maximum power density of 817 mW cm−2 at 600 °C and 605 mW cm−2 at 500 °C was achieved for fuel cell based on composite electrolyte. 相似文献
15.
In order to develop a simple and cost-effective route to fabricate proton-conductor intermediate-temperature SOFCs, a dense BaZr0.1Ce0.7Y0.2O3−δ (BZCY) electrolyte was fabricated on a porous anode by in situ drop-coating. The PrBaCuFeO5+δ (PBCF) composite oxide with layered perovskite structure was synthesized by auto ignition process and examined as a novel cathode for proton-conductor IT-SOFCs. The single cell, consisting of PBCF/BZCY/NiO-BZCY structure, was assembled and tested from 600 to 700 °C with humidified hydrogen (∼3% H2O) as the fuel and the static air as the oxidant. An open-circuit potential of 1.01 V and a maximum power density of 445 mW cm−2 at 700 °C were obtained for the single cell. A relatively low interfacial polarization resistance of 0.15 Ω cm2 at 700 °C indicated that the PBCF is a promising cathode for proton-conductor IT-SOFCs. 相似文献
16.
Anode-supported proton-conducting fuel cell with BaZr0.1Ce0.7Y0.2O3−δ (BZCY) electrolyte and Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) cathode was fabricated. Peak power densities of ∼420 and 135 mW/cm2 were achieved, respectively, at 700 and 450 °C for a cell with 35 μm thick electrolyte operating on hydrogen fuel. The endothermic nature of the ammonia decomposition reaction, however, resulted in cell temperature 30–65 °C lower than the furnace when operating on ammonia. Accounting the cooling effect, comparable power density was achieved for the cell operating on ammonia and hydrogen at high temperature. At reduced temperature, the cell demonstrated worse performance when operating on ammonia than on hydrogen due to the poor activity of the anode towards NH3 catalytic decomposition. By applying on-line catalytic decomposition products of N2H4 as the fuel, similar cell performance to that with NH3 fuel was also observed. 相似文献
17.
A dense and uniform 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3YSZ) electrolyte film of 6 μm in thickness was fabricated by slurry spin coating on a porous NiO/3YSZ anode substrate. Composite cathodes of La0.7Sr0.3MnO3 impregnated with Sm0.2Ce0.8O1.9 were fabricated on the 3YSZ films. A single cell produced in this way was tested at 700, 750 and 800 °C with hydrogen as fuel and stationary air as oxidant. Test results revealed an open-circuit voltage of 1.04 V at 800 °C, and maximum power density of 551, 895 and 1143 mW cm−2 at 700, 750 and 800 °C, respectively. Impedance spectra results demonstrated that the cell performance was determined by the polarization resistance of the cathode. 相似文献
18.
La2NiO4+δ, a mixed ionic-electronic conducting oxide with K2NiF4 type structure, has been studied as cathode material with La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) electrolyte for intermediate solid oxide fuel cells (IT-SOFCs). XRD results reveal excellent chemical compatibility between the La2NiO4+δ sample and LSGM electrolyte.A single cell (0.22 cm2 active area) was fabricated with La2NiO4+δ as cathode, Ni-Sm0.2Ce0.8O1.9 (2:1; w/w) as anode and LSGM as electrolyte. A thin buffer layer of Sm0.2Ce0.8O1.9 (SDC) between anode and electrolyte was used to avoid possible interfacial reactions. The cell was tested under humidified H2 and stationary air as fuel and oxidant, respectively. The electrochemical behaviour was evaluated by means of current-voltage curves and impedance spectroscopy. Microstructure and morphology of the cell components were analysed by SEM-EDX after testing.The maximum power densities were 160, 226, and 322 mW cm−2 at 750, 800 and 850 °C, respectively with total polarisation resistances of 0.77, 0.48 and 0.31 Ω cm2 at these temperatures. Cell performance remained stable when a current density of 448 mA cm−2 was demanded for 144 h at 800 °C, causing no apparent degradation in the cell. The performance of this material may be further improved by reducing the electrolyte thickness and optimisation of the electrode microstructure. 相似文献
19.
A dense membrane of Ce0.9Gd0.1O1.95 on a porous cathode based on a mixed conducting La0.6Sr0.4Co0.2Fe0.8O3−δ was fabricated via a slurry coating/co-firing process. With the purpose of matching of shrinkage between the support cathode and the supported membrane, nano-Ce0.9Gd0.1O1.95 powder with specific surface area of 30 m2 g−1 was synthesized by a newly devised coprecipitation to make the low-temperature sinterable electrolyte, whereas 39 m2 g−1 nano-Ce0.9Gd0.1O1.95 prepared from citrate method was added to the cathode to favor the shrinkage for the La0.6Sr0.4Co0.2Fe0.8O3−δ. Bi-layers consisting of <20 μm dense ceria film on 2 mm thick porous cathode were successfully fabricated at 1200 °C. This was followed by co-firing with NiO–Ce0.9Gd0.1O1.95 at 1100 °C to form a thin, porous, and well-adherent anode. The laboratory-sized cathode-supported cell was shown to operate below 600 °C, and the maximum power density obtained was 35 mW cm−2 at 550 °C, 60 mW cm−2 at 600 °C. 相似文献
20.
Feifei Dong Dengjie Chen Ran Ran Heejung Park Chan Kwak Zongping Shao 《International Journal of Hydrogen Energy》2012
Sm0.5Sr0.5MO3−δ (M = Co and Mn) materials are synthesized, and their properties and performance as cathodes for solid oxide fuel cells (SOFCs) on Sm0.2Ce0.8O1.9 (SDC) and Y0.16Zr0.92O2.08 (YSZ) electrolytes are comparatively studied. The phase structure, thermal expansion behavior, oxygen mobility, oxygen vacancy concentration and electrical conductivity of the oxides are systematically investigated. Sm0.5Sr0.5CoO3−δ (SSC) has a much larger oxygen vacancy concentration, electrical conductivity and TEC than Sm0.5Sr0.5MnO3−δ (SSM). A powder reaction demonstrates that SSM is more chemically compatible with the YSZ electrolyte than SSC, while both are compatible with the SDC electrolyte. EIS results indicate that the performances of SSC and SSM electrodes depend on the electrolyte that they are deposited on. SSC is suitable for the SDC electrolyte, while SSM is preferred for the YSZ electrolyte. A peak power density as high as 690 mW cm−2 at 600 °C is observed for a thin-film SDC electrolyte with SSC cathode, while a similar cell with YSZ electrolyte performs poorly. However, SSM performs well on YSZ electrolyte at an operation temperature of higher than 700 °C, and a fuel cell with SSM cathode and a thin-film YSZ electrolyte delivers a peak power density of ∼590 mW cm−2 at 800 °C. The poor performances of SSM cathode on both YSZ and SDC electrolytes are obtained at a temperature of lower than 650 °C. 相似文献