共查询到20条相似文献,搜索用时 15 毫秒
1.
Young-Wan Ju Shintaro IdaToru Inagaki Tatsumi Ishihara 《Journal of power sources》2011,196(15):6062-6069
The reoxidation behavior of a Ni-Fe metal anode supported cell using a thin LaGaO3 electrolyte film was investigated as a function of the reoxidation temperature. After oxidation and reduction treatments for 2 h, the voltage did not return to the initial voltage at higher temperatures (773-973 K); however, after reoxidation at 673 K, the cell exhibited almost the same OCV as the as-prepared cell. During reoxidation with air at the higher temperatures, the Ni-Fe metal substrate exhibited two different expansion behaviors by the different oxidation rates of Ni and Fe. On the other hand, the volumetric change of the oxidized substrate at 673 K was negligible. SEM-EDX results exhibited the reoxidation of Ni-Fe occurred only at the bottom part of the substrate and at the interface between the electrolyte and the substrate. In spite of temperatures as low as 673 K, the cell generated a power of 160 mW cm−2, which hardly decreased after the redox cycle. The increasing anodic internal resistance accompanied with unreduced Fe. 相似文献
2.
Tatsumi Ishihara Hiroyuki EtoJingWang Yan 《International Journal of Hydrogen Energy》2011,36(2):1862-1867
Dense La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM, 5 μm in thickness)/Ce0.8Sm0.2O2-δ (SDC, 400 nm in thickness) bilayer films were deposited on a dense NiO (Fe3O4)-SDC anode substrate by a pulsed laser deposition (PLD) method. After in-situ reduction, the substrate turned to be porous and it can be used as a porous anode substrate. The power density was strongly affected by the oxide ion conductor combined with LSGM and it was found that SDC is the most useful for achieving the high power density. Preparation of Sm0.5Sr0.5CoO3 cathode film by PLD method is also studied for decreasing the contact resistance of cathode. Preparation of SSC film by PLD is effective for decreasing cathodic overpotential and 400 nm thick film is the most effective for achieving the high power density. At 773 K, the maximum power density of the cell becomes higher than 500 mW/cm2. 相似文献
3.
In the current manufacturing process of novel LaNbO4-based proton conducting fuel cells a thin layer of the electrolyte is deposited by wet ceramic coating on NiO-LaNbO4 based anode and co-sintered at 1200-1300 °C. The chemical compatibility of NiO with acceptor doped LaNbO4 material is crucial to ensure viability of the cell, so potential effects of other phases resulting from off-stoichiometry in acceptor doped LaNbO4 should also be explored. Compatibility of NiO with Ca-doped LaNbO4 and its typical off-set compositions (La3NbO7 and LaNb3O9) are investigated in this work. It is shown that while NiO does not react with Ca-doped LaNbO4, fast reaction occurs with La3NbO7 or LaNb3O9. La3NbO7 and NiO form a mixed conducting perovskite phase LaNi2/3Nb1/3O3, while LaNb3O9 and NiO form either NiNb2O6 or Ni4Nb2O9 depending on the annealing temperature. This implies that manufacturing LaNbO4-based proton conducting fuel cells requires a strict control of the stoichiometry of the electrolyte. 相似文献
4.
In this work, solid oxide fuel cells were fabricated by ink-jet printing. The cells were characterized in order to study the resulting microstructure and electrochemical performance. Scanning electron microscopy revealed a highly conformal 6–12 μm thick dense yttria-stabilized zirconia electrolyte layer, and a porous anode-interlayer. Open circuit voltages ranged from 0.95 to 1.06 V, and a maximum power density of 0.175 W cm−2 was achieved at 750 °C. These results suggest that the ink-jet printing technique may be used to fabricate stable SOFC structures that are comparable to those fabricated by more conventional ceramics processing methods. This study also highlights the significance of overall cell microstructural impact on cell performance and stability. 相似文献
5.
Chunyu Zhu Akira Nobuta Young-Wan Ju Tatsumi Ishihara Tomohiro Akiyama 《International Journal of Hydrogen Energy》2013
This paper describes the potential of solution combustion synthesis (SCS) method for preparing Ce0.6Mn0.3Fe0.1O2 (CMF) as the anode material for solid oxide fuel cells (SOFC). The stability, crystallinity, morphology, and surface area of the products were depended on the fuel ratio used in SCS as investigated by TGA, XRD, SEM, and BET, which correspondingly influenced their electrochemical properties. The SCS-derived products were directly used for preparing anodes by sintering the screen-printed powders on the electrolyte membrane, and were evaluated from power generation performance, which were compared with the conventional solid-state-reaction (SSR) sample. Significantly, under configuration of the cell of CMF/La0.8Sr0.2Ga0.8Mg0.15Co0.05O3/Sm0.5Sr0.5CoO3 using humidified hydrogen gas as a fuel and O2 as an oxidizing agent, the maximum power densities obtained were 1.23 W/cm2 at 1000 °C for the SCS product (CMF1) obtained at ? = 0.5. This value was higher than 1.09 W/cm2 for the SSR-derived sample under the same evaluation conditions. The results appealed benefits of SCS method for preparing CMF as the anode material with high power generation performance for SOFC, due to its large surface area and nanosized grains, in which fuel ratio was a key parameter for its synthesis. 相似文献
6.
A new anode material for intermediate temperature solid oxide fuel cells (IT-SOFCs) with a composite of La0.7Sr0.3Cr1−xNixO3 (LSCN), CeO2 and Ni has been synthesized. EDX analysis showed that 1.19 at% Ni was doped into the perovskite-type La0.7Sr0.3CrO3 and Ce could not be detected in the perovskite phases. Results showed that the fine CeO2 and Ni were highly dispersed on the La0.7Sr0.3Cr1−xNixO3 substrates after calcining at 1450 °C and reducing at 900 °C. The thermal expansion coefficient (TEC) of the as-prepared anode material is 11.8 × 10−6 K−1 in the range of 30–800 °C. At 800 °C, the electrical conductivity of the as-prepared anode material calcined at 1450 °C for 5 h is 1.84 S cm−1 in air and 5.03 S cm−1 in an H2 + 3% H2O atmosphere. A single cell with yttria-stabilized zirconia (YSZ, 8 mol% Y2O3) electrolyte and the new materials as anodes and La0.8Sr0.2MnO3 (LSM)/YSZ as cathodes was assembled and tested. At 800 °C, the peak power densities of the single cell was 135 mW cm−2 in an H2 + 3% H2O atmosphere. 相似文献
7.
Zhou DaiJian Pu Dong YanBo Chi Li Jian 《International Journal of Hydrogen Energy》2011,36(4):3131-3137
Al2O3-based compressive seals were fabricated by tape casting with Al2O3 and 0-30 wt% aluminum powders, and their sealing effectiveness, thermal cycle stability between 200 and 750 °C and applicability in planar intermediate temperature solid oxide fuel cells were evaluated. The results indicate that increasing the aluminum content from 0 to 30 wt% in the seals decreases the leakage rate and increases the thermal cycle stability under various inlet gas (N2) pressures of 3.5, 7.0 and 10.5 kPa. Especially, with the seal containing 30 wt% of aluminum (ACS3), the initial leakage rate was below 0.03 sccm cm−1 under an inlet pressure of 10.5 kPa, and the leakage rates during 96 thermal cycles were below 0.04 sccm cm−1 under the same inlet gas pressure. The interfaces in the interconnect/seal/cell assembly with the ACS3 seal retained integrity after 50 thermal cycles, demonstrating the applicability of the Al2O3-based compressive seals in the planar intermediate temperature SOFCs. 相似文献
8.
Xian-Zhu Fu Juri Melnik Qing-Xun Low Jing-Li Luo Karl T. Chuang Alan R. Sanger Quan-Min Yang 《International Journal of Hydrogen Energy》2010
Cu surface modified nickel foam is obtained by heating copper coated nickel foam in a reducing atmosphere. La0.75Sr0.25Cr0.5Mn0.5O3−δ (LSCM) perovskite oxide is prepared using a sol–gel combustion method. The modified foams and LSCM powders exhibit excellent resistance to carbon deposition in syngas at high temperatures. Furthermore, Cu modified foams show better mechanical strength compared to bare Ni foam, which readily cracks after exposure to syngas at high temperature. LSCM retains its perovskite structure during exposure to syngas or carbon monoxide at 900 °C for 10 h. Cu surface modified Ni foam current collector demonstrates good chemical compatibility with LSCM in syngas atmosphere at high temperature. Syngas solid oxide fuel cells (SOFCs) are assembled using Cu modified Ni foam anode current collector, LSCM anode catalyst, YSZ electrolyte, and porous Pt cathode. The present fuel cell provides similar power density to one with gold anode current collector and has excellent stability during operation at 900 °C. 相似文献
9.
Chi-Chieh Yao Dah-Shyang Tsai Jen-Chieh Lo Wen-Hung Chung David P. Wilkinson 《International Journal of Hydrogen Energy》2012
Various anode-supported solid oxide fuel cells (SOFC), based on 10 mol% Dy-doped La2Mo2O9 (LDM) electrolyte, are prepared analytically and operated under single chamber conditions to explore the connections between electrode and power performance. The cathode of tested SOFCs is compositionally graded with three composites of samarium strontium cobaltite and Gd-doped ceria (GDC) to relax the thermal stress, because of sizable thermal expansion differences above 400 °C. We focus the research attention on varying the anode pore structure and composition to promote the power performance in methane/air mixture at 700 °C. For the one-layer support of GDC+NiO+LDM anode, addition of 10 wt% graphite minimizes its mass transport resistance through creating 8–5 μm long and ∼1 μm wide slit-shaped pores. The graphite pore former raises the peak power value by 80 mW cm−2. Adopting a more porous and active outer layer, the double-layer support further enhances the cell power. The peak power was first raised by 48 mW cm−2, using an outer layer that was prepared with 63 wt% NiO. Dosing 3% Pd on this outer layer uplifts another 59 mW cm−2. In this study, with an improved anode, the peak power value reaches 437 mW cm−2. 相似文献
10.
Chuan WangXianshuang Xin Yanjie XuXiaofeng Ye Lijun YuShaorong Wang Tinglian Wen 《Journal of power sources》2011,196(8):3841-3845
The electrochemical performance of LSM-Pd composite material as current collector of SOFC cathode is studied on (La0.8Sr0.2)0.9MnO3 (LSM90) cathode. The influence of Pd content on contact resistance is investigated. The investigation shows that the contact resistance of LSM-Pd is about 20 mΩ cm2 at 750 °C when the composite contains 8 wt% Pd, and it could be comparable to pure Pt. The ohmic resistance of a single cell using LSM-Pd composite is about 255 mΩ cm2 that contains 4 wt% Pd as current collector, this value is close to that of a cell using expensive Pt paste as current collector. 相似文献
11.
Biogas is a variable mixture of methane, carbon dioxide and other gases. It is a renewable resource which comes from numerous sources of plant and animal matter. Ni-YSZ anode-supported solid oxide fuel cell (SOFC) can directly use clean synthesized biogas as fuel. However, trace impurities, such as H2S, Cl2 and F2 in real biogas can cause degradation in cell performance. In this research, both uncoated and coated Ni-YSZ anode-supported cells were exposed to three different compositions of synthesized biogases (syn-biogas) with 20 ppm H2S under a constant current load at 750-850 °C and their performance was evaluated periodically using standard electrochemical methods. Postmortem analysis of the SOFC anode was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that H2S causes severe electrochemical degradation of the cell when operating on biogas, leading to both complete electrochemical and mechanical failure. The Ni-CeO2 coated cell showed excellent stability during CH4 reforming and some tolerance to H2S contamination. 相似文献
12.
Chuan WangXianshuang Xin Yanjie XuJianyin Chen Le ShaoJuan Zhou Shaorong Wang Tinglian Wen 《International Journal of Hydrogen Energy》2011,36(13):7683-7687
A new system, (La0.8Sr0.2)1−xAgxMnO3+δ (LSAM, x ≤ 0.2), is developed as current collector for solid oxide fuel cell (SOFC). LSAM is prepared by a modified sol-gel method and presents a single phase. The shrinkage temperature reduces from 1150 °C to 800 °C with an addition of 15 mol% Ag to La0.8Sr0.2MnO3+δ (LSM20). The contact resistance between the current collector and the cathode is measured, and the influence of Ag content on the contact resistance is investigated. The result shows that the contact resistance using (La0.8Sr0.2)0.85Ag0.15MnO3+δ (LSAM15) as current collector is about 12 mΩ cm2 at 750 °C, which is close to the value using expensive Pt paste as current collector. This new system is a promising current collecting material for the practical application of SOFC. 相似文献
13.
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
14.
Young Min ParkJu Hee Kim Haekyoung Kim 《International Journal of Hydrogen Energy》2011,36(15):9169-9179
The composite cathodes with lanthanum-based iron and cobalt-containing perovskite La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) and Ce0.9Gd0.1O1.95 (GDC) are investigated for solid oxide fuel cell (SOFC) applications at relatively low operating temperatures (700-800 °C). LSCFs with high surface areas of 55 m2g−1 are synthesized via a complex method with inorganic nano dispersants. The fuel cell performances of composite cathodes on anode supported SOFCs are characterized with GDC materials of surface areas of 5 m2g−1 (ULSA-GDC), 12 m2g−1 (LSA-GDC), and 23 m2g−1 (HAS-GDC). The maximum power density of the SOFCs increases from 0.68 Wcm−2 to 1.2 Wcm−2 at 780 °C and 0.8 V as the GDC surface area increases from 5 m2g−1 to 23 m2g−1. The area specific resistance of the porous composite cathodes with a HAS-GDC are 0.467 ohmcm2 at 780 °C and 1.086 ohmcm2 at 680 °C, while these values with an LSA-GDC are 0.543 ohmcm2 and 0.945 ohmcm2, respectively. The best compositions of the porous composite cathodes result from the morphologies of the GDC materials at each temperature due to the formation of an electron-oxygen ion-gas boundary. 相似文献
15.
Shu-en HouAinara Aguadero José Antonio AlonsoJohn B. Goodenough 《Journal of power sources》2011,196(13):5478-5484
A solid-oxide fuel cell (SOFC) based upon Fe perovskites, has been designed and tested. Materials with nominal compositions Sr0.9K0.1FeO3−δ (SKFO) and Sr1.6K0.4FeMoO6−δ (SKFMO) with perovskite structure have been prepared and characterized as cathode and anode, respectively. The anode material exhibits high electrical conductivity values of 407-452 S cm−1 at 750-820 °C in pure H2. In the test cells, the electrodes were supported on a 300-μm-thick pellet of the electrolyte La0.8Sr0.2Ga0.83Mg0.17O3−δ (LSGM). The single SOFC cells gave a maximum power density at 850 °C of 937 mW cm−2 with pure H2 as a fuel. Sizeable power densities were also observed with alternative fuels: 694 and 499 mW cm−2 with H2 containing 5 parts per million of H2S and CH4, respectively, at 800 °C. Moreover, only a slight degradation of about 3.6% of the power density has been obtained after 65 different cycles of fuel-cell test in H2 at 750 °C and 14% at 850 °C in 50 cycles using H2-H2S. This remarkable behavior has been correlated to the structural features determined in a neutron powder diffraction experiment in the usual working conditions of a SOFC for a cathode (air) and an anode (low pO2). On the one hand, the cubic Pm-3m Sr0.9K0.1FeO3−δ cathode material is an oxygen deficient perovskite with oxygen contents that vary from 2.45(2) to 2.26(2) from 600 to 900 °C and high oxygen isotropic thermal factors (4.17(8) Å2) suggesting a high ionic mobility. On the other hand, the actual nature of the anode of composition Sr1.6K0.4FeMoO6−δ has been unveiled by neutron powder diffraction to consist of two main perovskite phases with the compositions SrMoO3 and SrFe0.6Mo0.4O2.7. The association of two perovskites oxides, SrMoO3 with high electrical conductivity, and SrFe0.6Mo0.4O2.7 with mixed ionic-electronic conductivity has resulted in an extraordinarily performing anode material for SOFCs. 相似文献
16.
The apatite-type lanthanum silicate films were successfully synthesized by modified atmosphere plasma spraying using lanthanum oxide and silicon oxide mixed powders and precalcined hypereutectic powders in the size range 1–3 μm and 5–8 μm, respectively, as starting feedstock materials. The films differed not only in microstructural scale, but also in the characteristic of the degree of film densification. A detail describing the evolution of microstructure has been discussed. A considerable improvement in densification of the La10(SiO4)6O3 electrolyte films has been observed. 相似文献
17.
Wei Yang Chunling Zhu Zhaohui Ma Chunwen Sun Liquan Chen Yujin Chen 《International Journal of Hydrogen Energy》2014
MoO3 nanorods/Fe2(MoO4)3 nanoparticles composite has been prepared by a hydrothermal method combined with an in situ diffusion growth process. Single cells based on 300 μm LSGM electrolyte have been fabricated with the MoO3 nanorods/Fe2(MoO4)3 nanoparticles composite anode and a composite cathode consisting of Sr0.9Ce0.1CoO3−δ and Sm-doped ceria (SDC). The peak power densities reach 225, 50, 75 mW cm−2 at 900 °C in H2, CH4 and C3H8, respectively. The cell shows excellent long-term stability at 850 °C. The preliminary results demonstrate that the MoO3 nanorods/Fe2(MoO4)3 nanoparticles composite is a promising alternative anode for solid oxide fuel cells. 相似文献
18.
Yingchao Dong Stuart HampshireJian-er Zhou Xinfa DongBin Lin Guangyao Meng 《Journal of power sources》2011,196(20):8402-8405
Combustion processed nano-sized Ce0.79Sm0.20Co0.01O2−δ (CSCoO) and Ce0.80Sm0.20O2−δ (CSO) were sintered at various temperatures, and mechanical properties and microstructures were characterized. The results demonstrate that besides a lowering of sintering temperature to achieve sufficient densification, the doping of very minor amounts of CoO (1 mol%) to CSO significantly enhanced mechanical properties. The CSCoO sintered at 1100 °C exhibits a biaxial flexural strength of 354 ± 42 MPa which compared with 194 ± 57 MPa for CSO with a similar relative density sintered at 1400 °C. This slight modification in chemical composition also resulted in a slight improvement in micro-hardness. 相似文献
19.
Xue Li Hailei Zhao Nansheng Xu Xiong Zhou Cuijuan Zhang Ning Chen 《International Journal of Hydrogen Energy》2009
The effects of La- and Co-doping into SrTiO3 perovskite oxides on their phase structure, electrical conductivity, ionic conductivity and oxygen vacancy concentration have been investigated. The solid solution limits of La in LaxSr1 − xTiO3 − δ and Co in La0.3Sr0.7CoyTi1 − yO3 − δ are about 40 mol% and 7 mol%, respectively, at 1500 °C. The incorporation of La decreases the band gap and thus increases the electrical conductivity of SrTiO3 remarkably. La0.3Sr0.7TiO3 − δ shows an electrical conductivity of 247 S/cm at 700 °C. Co-doping into La0.3Sr0.7TiO3 − δ increases the oxygen vacancy concentration and decreases the migration energy for oxygen ions, leading to a significant increase in ionic conductivity but at the expense of some electrical conductivity. The electrical and ionic conductivities of La0.3Sr0.7Co0.07Ti0.93O3 − δ are 63 S/cm and 6 × 10−3 S/cm, respectively, at 700 °C. Both La0.3Sr0.7TiO3 − δ and La0.3Sr0.7Co0.07Ti0.93O3 − δ show relatively stable electrical conductivities under oxygen partial pressure of 10−14–10−19 atm at 800 °C. These properties make La0.3Sr0.7Co0.07Ti0.93O3 − δ a promising anode candidate for solid oxide fuel cells. 相似文献
20.
Novel compressive Al2O3-based seals were developed and characterized under simulated intermediate temperature solid oxide fuel cell (IT-SOFC) environment. The seals were prepared by tape casting, mainly composed of fine Al2O3 powder with various contents of fine Al powder addition. The leakage rates were determined at 800 °C under 0.14–0.69 MPa compressive stresses, and the stabilities were evaluated at 750 °C under constant 0.35 MPa compressive stress. The leakage rates at 800 °C were in range of 0.2–0.01 sccm cm−1, decreasing with increasing the compressive stress and Al content; Al addition significantly improved the stability, the leakage rate with 20 wt% Al addition was as low as 0.025 sccm cm−1 at 800 °C under 0.35 MPa compressive stress with a gauge pressure of 6.9 kPa, and exhibited good stability at 750 °C. Single cell test also confirmed the effectiveness of the tape cast Al2O3-based seal for planar IT-SOFC applications. 相似文献