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1.
Peng Qiu Shichen Sun Xin Yang Fanglin Chen Chunyan Xiong Lichao Jia Jian Li 《International Journal of Hydrogen Energy》2021,46(49):25208-25224
The commercialization of solid oxide fuel cells (SOFCs) can be significantly promoted with the direct utilization of methane, which is the primary component in natural gas and the second most abundant anthropogenic greenhouse gas. However, carbon deposition on most commonly used Ni-based anode is the bottle-necking issue inhibiting long-term stability of direct methane SOFCs. To avoid such a problem, methane is typically reformed (internally or externally) in SOFCs. Considering the cost, system simplification, coking resistance, and material selection, the on-cell catalytic reforming layer (OCRL) is one of the most promising designs for direct methane SOFCs. Reforming catalytic materials are typically consisted of active component, substrate and catalytic promoter, all of which have a significant impact on the catalytic activity, sintering resistance and coking resistance of methane reforming catalysts. This review summarizes the influence of the various components, some common OCRL materials and their applications in direct methane SOFCs, reforming and coking resistance mechanism, as well as the remaining challenges. The effective utilization of OCRL plays a pivotal role in promoting the development of direct methane SOFCs and the commercialization of SOFCs. 相似文献
2.
Directly using methane in solid oxide fuel cells (SOFC) requires the knowledge of the reaction of methane over the anode. The reactions of low and middle concentration dry methane were studied over the anode of solid oxide fuel cell with Ni/yttria-stabilized zirconia (YSZ) anode and YSZ electrolyte. The production rates of different types of gas at anode outlet were measured at different current density. Mass balance and relationships between production rates and reaction rates were used to analyze the chemical and electrochemical reactions that took place in parallel. When dry methane is in low concentration, methane decomposition and deposited carbon oxidation occurs at low current density with the overall reaction being partial oxidation of methane (POM). With increased current density, hydrogen oxidation and carbon monoxide oxidizing to carbon dioxide take place simultaneously, and the overall reaction becomes the direct oxidation of methane (DOM). When DOM occurs, a portion of methane participates the POM. However, the rate of POM decreases with increased current density. At medium methane concentration, only partial oxidation of methane takes place. Carbon deposition was found in all the tests across the concentration range investigated. 相似文献
3.
Combined Cu‐CeO2 /YSZ and Ni/YSZ dual layer anode structures for direct methane solid oxide fuel cells
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In this study, a conventional Ni/yttria‐stabilized zirconia (YSZ) anode and a new Cu‐CeO2‐YSZ anode structure were assembled in an attempt to combine the advantages of both structures for use in direct methane solid oxide fuel cells. For this purpose, only a limited region (≤20 μm) of NiO/YSZ was deposited at the boundary of the electrolyte to benefit from the superior catalytic activity of Ni in the cells, while the rest of the cell benefited from the Cu‐CeO2‐YSZ anode structure, which does not cause cracking reactions. First, the effects of different pore formers on the anode skeleton, as well as the interactions of the Ni‐Cu species in the anode skeleton, are discussed. Then, the NiO/YSZ‐interlayer‐containing button cells with different thicknesses (≤20) and different ratios of NiO (40 wt%, 50 wt%, and 60 wt%) were studied. After the examination of the cells, 2 model cells with outstanding performance and 2 additional internal reference cells, conventional Ni/YSZ and Cu‐CeO2‐YSZ, were scaled up, and performance analysis and long‐term stability studies were carried out. As a result, for solid oxide fuel cells with increased carbonization resistance (around 6% performance loss due to carbonization after 100‐hour stability testing) and 86.1% of the initial performance of the conventional Ni/YSZ anode structure, a 15‐μm‐thick 40 wt% NiO/60 wt% YSZ interlayer with a dual layer anode structure is proposed. 相似文献
4.
《International Journal of Hydrogen Energy》2020,45(51):27587-27596
Natural gas is one of the most attractive fuels for solid oxide fuel cell (SOFC), while the anode activity for methane fuel has a great influence on the performance and stability of SOFC. Samarium is a good catalyst promoter for methane reforming. In this work, samarium is used to modify nickel catalyst, which results in small nickel oxide particles. The SmNi-YSZ (yttria-stabilized zirconia) anode has smaller particles and better interfacial contact between nickel and YSZ compared with conventional Ni-YSZ anode. The fine structure of SmNi-YSZ anode results in high activity for electrochemical oxidation of hydrogen and low polarization resistance of the cell. The performance of SmNi-YSZ anode cell with humidified methane as fuel is greatly improved, which is similar to that with hydrogen as fuel. The maximum power densities of SmNi-YSZ anode cell are 1.56 W cm−2 for humidified hydrogen fuel and 1.54 W cm−2 for humidified methane fuel at 800 °C. The maximum power density is increased by 221% when samarium is used to modify Ni-YSZ anode for humidified methane fuel at 650 °C. High cell performance results in good stability of SmNi-YSZ anode cell and the cell runs stably for more than 600 min for humidified methane fuel. 相似文献
5.
The electrolyte of a solid oxide fuel cell (SOFC) is an O2−-ion conductor. The anode must oxidize the fuel with O2− ions received from the electrolyte and it must deliver electrons of the fuel chemisorption reaction to a current collector. Cells operating on H2 and CO generally use a porous Ni/electrolyte cermet that supports a thin, dense electrolyte. Ni acts as both the electronic conductor and the catalyst for splitting the H2 bond; the oxidation of H2 to H2O occurs at the Ni/electrolyte/H2 triple-phase boundary (TPB). The CO is oxidized at the oxide component of the cermet, which may be the electrolyte, yttria-stabilized zirconia, or a mixed oxide-ion/electron conductor (MIEC). The MIEC is commonly a Gd-doped ceria. The design and fabrication of these anodes are evaluated. Use of natural gas as the fuel requires another strategy, and MIECs are being explored for this application. The several constraints on these MIECs are outlined, and preliminary results of this on-going investigation are reviewed. 相似文献
6.
An additional layer in an anode support for internal reforming of methane for solid oxide fuel cells
Anode supported solid oxide fuel cells (SOFCs) have been extensively investigated for their ease of fabrication, robustness, and high electrochemical performance. SOFCs offer a greater flexibility in fuel choice, such as methane, ethanol or hydrocarbon fuels, which may be supplied directly on the anode. In this study, SOFCs with an additional Ni–Fe layer on a Ni–YSZ support are fabricated with process variables and characterized for a methane fuel application. The addition of Ni–Fe onto the anode supports exhibits an increase in performance when methane fuel is supplied. SOFC with a Ni–Fe layer, sintered at 1000 °C and fabricated using a 20 wt% pore former, exhibits the highest value of 0.94 A cm−2 and 0.85 A cm−2 at 0.8 V with hydrogen and methane fuel, respectively. An impedance analysis reveals that SOFCs with an additional Ni–Fe layer has a lower charge transfer resistance than SOFCs without Ni–Fe layer. To obtain the higher fuel cell performance with methane fuel, the porosity and sintering temperature of an additional Ni–Fe layer need to be optimized. 相似文献
7.
A new ceramic-based multi-component material, containing one electronic conductor (Y-substituted SrTiO3, SYT), one ionic conductor (YSZ) and a small amount (∼5 vol.%) of Ni catalyst, was investigated as an alternative anode material for solid oxide fuel cells (SOFCs). The ceramic framework SYT/YSZ shows good dimensional stability upon redox cycling and has an electrical conductivity of ∼10 S cm−1 under typical anode conditions. Owing to the substantial electrocatalytic activity of the fine and well-dispersed Ni particles on the surface of the ceramic framework, the electrode polarization resistance of 5 vol.% Ni-impregnated SYT/YSZ anode reached 0.21 Ω cm2 at 800 °C in wet Ar/5%H2. Based on these results, a redox-stable anode-supported planar SOFC is expected using this anode material, thus offering great advantages over the current generation of Ni/YSZ-based SOFCs. 相似文献
8.
NiO/YSZ hollow fibers were fabricated via a combined phase inversion and sintering technique, where polyethersulfone (PESf) was employed as the polymeric binder, N-methyl-2-pyrrolidone (NMP) as the solvent and polyvinylpyrrolidone (PVP) as the additive, respectively. After reduction with hydrogen at 750 °C for 5 h, the porous Ni/YSZ hollow fibers with an asymmetric structure comprising of a microporous layer integrated with a finger-like porous layer were obtained, which can be served as the anode support of micro-tubular solid oxide fuel cells (SOFCs). As the sintering temperature was increased from 1200 to 1400 °C, the mechanical strength and the electrical conductivity of the Ni/YSZ hollow fibers increased from 35 to 178 MPa and from 30 to 772 S cm−1, respectively but the porosity decreased from 64.2% to 37.0%. The optimum sintering temperature was found to be between 1350 and 1400 °C for Ni/YSZ hollow fibers applied as the anode support for micro-tubular SOFCs. 相似文献
9.
Solid oxide fuel cells (SOFCs) are electrochemical reactors that can directly convert the chemical energy of a fuel gas into electrical energy with high efficiency and in an environment-friendly way. The recent trends in the research of solid oxide fuel cells concern the use of available hydrocarbon fuels, such as natural gas. The most commonly used anode material Ni/YSZ cermet exhibits some disadvantages when hydrocarbons were used as fuels. Thus it is necessary to develop alternative anode materials which display mixed conductivity under fuel conditions. This article reviews the recent developments of anode in SOFCs with principal emphasis on the material aspects. In addition, the mechanism and kinetics of fuel oxidation reactions are also addressed. Various processes used for the cost-effective fabrication of anode have also been summarized. Finally, this review will be concluded with personal perspectives on the future research directions of this area. 相似文献
10.
《International Journal of Hydrogen Energy》2021,46(73):36445-36453
Thin film solid oxide fuel cells (TF–SOFCs) having anode–substrate nanostructure that was optimized for the low-temperature operation were fabricated. Nickel thin film anodes with four different anode thicknesses were deposited on anodic aluminum oxide templates, nanoporous substrates having two different pore sizes, by the sputtering method. Subsequently, a yttria-stabilized zirconia (YSZ) electrolyte and platinum cathode were deposited on them, which completed the entire fuel cell structure. The anode nanostructure of fuel cells in six combinations was analyzed by the cross-sectional view, surface microscopy method, and three-dimensional morphology observation. Those investigations enabled the anode nanostructure to be identified, such as the anode porosity and the roughness of the interface between anodes and electrolytes. Then, the six TF–SOFCs were electrochemically characterized in a 500 °C operating environment. The maximum power densities were obtained through the i–V–P curves, and the highest performance of 294.1 mW/cm2 was measured in the cell having a combination of 200 nm–sized porous aluminum anodic oxide (AAO) and 1200 nm–thick Ni anode. This showed up to 20.1% improvement over the other cells. EIS analysis showed that the optimized ohmic and faradaic resistance originated from each part of the unique TF–SOFC structure. 相似文献
11.
Solid oxide fuel cell bi-layer anode with gadolinia-doped ceria for utilization of solid carbon fuel
Pyrolytic carbon was used as fuel in a solid oxide fuel cell (SOFC) with a yttria-stabilized zirconia (YSZ) electrolyte and a bi-layer anode composed of nickel oxide gadolinia-doped ceria (NiO-GDC) and NiO-YSZ. The common problems of bulk shrinkage and emergent porosity in the YSZ layer adjacent to the GDC/YSZ interface were avoided by using an interlayer of porous NiO-YSZ as a buffer anode layer between the electrolyte and the NiO-GDC primary anode. Cells were fabricated from commercially available component powders so that unconventional production methods suggested in the literature were avoided, that is, the necessity of glycine-nitrate combustion synthesis, specialty multicomponent oxide powders, sputtering, or chemical vapor deposition. The easily-fabricated cell was successfully utilized with hydrogen and propane fuels as well as carbon deposited on the anode during the cyclic operation with the propane. A cell of similar construction could be used in the exhaust stream of a diesel engine to capture and utilize soot for secondary power generation and decreased particulate pollution without the need for filter regeneration. 相似文献
12.
A new type of Ni-free anode material based on Co0.5Fe0.5 + SDC (Sm0.2Ce0.8O1.9) was identified and evaluated using the La0.8Sr0.2Ga0.83Mg0.17O3 (LSGM) electrolyte-supported cells. The maximum power densities with humidified hydrogen at 800 °C using Au mesh and Pt mesh as anode current collector were 1.07 and 1.20 W cm−2, respectively, which were comparable to that of the cell with the Ni + SDC anode. The cell with the new anode exhibited reasonable performance stability at 800 °C in hydrogen fuel; furthermore, no noticeable change in cell performance with the Co0.5Fe0.5 alloy anode was observed upon ordering reaction in the alloy to form the ordered α′ phase at 650 °C. 相似文献
13.
Bora Timurkutluk Cigdem TimurkutlukMahmut D. Mat Yuksel Kaplan 《Journal of power sources》2011,196(22):9361-9364
Novel three-layered intermediate temperature solid oxide fuel cell (SOFC) electrolytes based on gadolinium doped ceria (GDC) are developed to suppress the electronic conductivity of GDC, to improve the mechanical properties of the cell and to minimize power loss due to mixed conductive nature of GDC. Three different electrolytes are fabricated by sandwiching thin YSZ, ScSZ and ScCeSZ between two relatively thick GDC layers. An electrolyte composed of pure GDC is also manufactured for comparison. NiO/GDC and LSCF/GDC electrodes are then coated on the electrolytes by a screen printing route. SEM results show that it is possible to obtain dense and crack free thin layers of YSZ, ScSZ and ScCeSZ between two GDC layers without delamination. Performance measurements indicate that interlayered thin electrolytes act as an electronic conduction barrier and improve open circuit voltages (OCVs) of GDC based cells. 相似文献
14.
Sun-Dong Kim Jong-Jin Lee Hwan Moon Sang-Hoon Hyun Jooho Moon Joosun Kim Hae-Weon Lee 《Journal of power sources》2007
To improve the performance of anode-supported solid oxide fuel cells (SOFCs), various types of single cells are manufactured using a thin-film electrolyte of Yttria stabilized zirconia (YSZ) and an anode functional layer composed of a NiO–YSZ nano-composite powder. Microstructural/electrochemical analyses are conducted. Single-cell performances are highly dependent on electrolyte thickness, to the degree that the maximum power density increases from 0.74 to 1.12 W cm−2 according to a decrease in electrolyte thickness from 10.5 to 6.5 μm at 800 °C. The anode functional layer reduced the polarization resistance of a single cell from 1.07 to 0.48 Ω cm2 at 800 °C. This is attributed to the provision by the anode layer of a highly reactive and uniform electrode microstructure. It is concluded that optimization of the thickness and homogeneity of component microstructure improves single-cell performances. 相似文献
15.
Hongxin You Hongjie GaoGang Chen Abuliti AbudulaXinwei Ding 《Journal of power sources》2011,196(5):2779-2784
Dry methane with different concentrations is directly fed to solid oxide fuel cells (SOFCs) with a Ni-yttria-stabilized zirconia (Ni-YSZ) anode and a Ni-scandia-stabilized zirconia (Ni-ScSZ) anode. The anode outlet gases are measured in situ by gas chromatography (GC) to study the reactions of dry methane at different current densities. The comparison between the measured open-circuit voltages (OCVs) and theoretical values, the quantitative analysis of components under different current densities and the activation energy analysis of elementary reactions of CH4 are investigated to identify the types of reactions occurring to methane in SOFCs. It is found that reactions of partial oxidation, CH4 + 2O2− → CO + H2O + H2 + 4e−, CH4 + 3O2− → CO + 2H2O + 6e−, and complete oxidation occur to CH4 at the Ni-based anodes in sequence while the current density increasing. 相似文献
16.
Yu LiuYoumin Guo Wei WangChao Su Ran RanHuanting Wang Zongping Shao 《Journal of power sources》2011,196(22):9246-9253
This study investigates dimethyl ether (DME) as a potential fuel for proton-conducting SOFCs with a conventional nickel cermet anode and a BaZr0.4Ce0.4Y0.2O3−δ (BZCY4) electrolyte. A catalytic test demonstrates that the sintered Ni + BZCY4 anode has an acceptable catalytic activity for the decomposition and steam reforming of DME with CO, CH4 and CO2 as the only gaseous carbon-containing products. An O2-TPO analysis demonstrates the presence of a large amount of coke formation over the anode catalyst when operating on pure DME, which is effectively suppressed by introducing steam into the fuel gas. The selectivity towards CH4 is also obviously reduced. Peak power densities of 252, 280 and 374 mW cm−2 are achieved for the cells operating on pure DME, a DME + H2O gas mixture (1:3) and hydrogen at 700 °C, respectively. After the test, the cell operating on pure DME is seriously cracked whereas the cell operating on DME + H2O maintains its original integrity. A lower power output is obtained for the cell operating on DME + H2O than on H2 at low temperature, which is mainly due to the increased electrode polarization resistance. The selection of a better proton-conducting phase in the anode is critical to further increase the cell power output. 相似文献
17.
Tubular electrolyte-supporting solid oxide fuel cells directly operated on carbon fuel were fabricated and tested. Gadolinia doped ceria (GDC) mixed with silver was used as the anode to catalyze the electrochemical oxidation of CO while Fe-based catalyst was loaded on the carbon fuel to enhance the Boudouard reaction. The performance was significantly improved, with a maximum power density of 45 mW cm−2, 10 times higher than that of the cell without any catalyst. Impedance measurements showed that the polarization resistance was decreased by tens of times through applying catalysts in the cell. An operation life of 10 h was observed at a constant current of 70 mA. The mechanism of the cell reaction was analyzed. 相似文献
18.
《International Journal of Hydrogen Energy》2019,44(36):20404-20415
Ni-based cermets are most commonly used anode materials for solid-oxide fuel cells (SOFCs), but poor stability operating on hydrocarbon fuels seriously hampers their commercialization due to carbon deposition and sulfur poisoning. Here, we report a carbon– and sulfur–tolerant double perovskite anode Sr2TiMoO6−δ (STMO) combining the characteristics of two simple perovskites of SrTiO3 and SrMoO3. The STMO anode exhibits excellent thermal and chemical compatibility with La0.9Sr0.1Ga0.8Mg0.2O3–δ (LSGM) and Ce0.8Sm0.2O1.9 (SDC) electrolytes in 5% H2/Ar. The single cell with STMO anode demonstrates good stability and excellent coking resistance and sulfur tolerance in H2S-containing syngas during a 60-h period. The maximum power density (Pmax) values of a LSGM-electrolyte-supported single cell with STMO anode are 505 and 275 mW cm−2at 850 °C in H2 and H2S-containing syngas, respectively. The electrochemical performance is further improved by impregnation of Pd nanoparticles, where the Pmax values achieve 1009 and 586 mW cm−2 at 850 °C under the same conditions, respectively, showing great potential as an anode material for SOFCs operating on H2S-containing syngas. Our study provides a strategy to develop versatile double perovskite materials by combining the relevant characteristics of two separate perovskites. 相似文献
19.
Yaohui Bai Chuanling Wang Jiao Ding Chao Jin Jiang Liu 《Journal of power sources》2010,195(12):3882-9969
Operation of cone-shaped anode-supported segmented-in-series solid oxide fuel cell (SIS-SOFC) stack directly on methane is studied. A cone-shaped solid oxide fuel cell stack is assembled by connecting 11 cone-shaped anode-supported single cells in series. The 11-cell-stack provides a maximum power output of about 8 W (421.4 mW cm−2 calculated using active cathode area) at 800 °C and 6 W (310.8 mW cm−2) at 700 °C, when operated with humidified methane fuel. The maximum volumetric power density of the stack is 0.9 W cm−3 at 800 °C. Good stability is observed during 10 periods of thermal cycling test. SEM-EDX measurements are taken for analyzing the microstructures and the coking degrees. 相似文献
20.
Hideto Kurokawa Liming YangCraig P. Jacobson Lutgard C. De JongheSteven J. Visco 《Journal of power sources》2007
A solid oxide fuel cell (SOFC) anode with high sulfur tolerance was developed starting from a Y-doped SrTiO3 (SYTO)-yttria stabilized zirconia (YSZ) porous electrode backbone, and infiltrated with nano-sized catalytic ceria and Ru. The size of the infiltrated particles on the SYTO-YSZ pore walls was 30–200 nm, and both infiltrated materials improved the performance of the SYTO-YSZ anode significantly. The infiltrated ceria covered most of the surface of the SYTO-YSZ pore walls, while Ru was dispersed as individual nano-particles. The performance and sulfur tolerance of a cathode supported cell with ceria- and Ru-infiltrated SYTO-YSZ anode was examined in humidified H2 mixed with H2S. The anode showed high sulfur tolerance in 10–40 ppm H2S, and the cell exhibited a constant maximum power density 470 mW cm−2 at 10 ppm H2S, at 1073 K. At an applied current density 0.5 A cm−2, the addition of 10 ppm H2S to the H2 fuel dropped the cell voltage slightly, from 0.79 to 0.78 V, but completely recovered quickly after the H2S was stopped. The ceria- and Ru-infiltrated SYTO-YSZ anode showed much higher sulfur tolerance than conventional Ni-YSZ anodes. 相似文献