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91.
92.
The present work is focused in the study of the bimetallic Cu–Co formulation combined with CeO2 as SOFC anode, at 750 °C, direct feed of methane and two different fuel mixtures that simulate biogas. Additionally, the sulphur tolerance of new anode material has been evaluated. Its single cell evaluation, based on a samaria doped ceria (SDC) solid electrolyte and a LSM perovskite cathode, together with the electrochemical characterisation and catalytic activity tests, have allowed to demonstrate the ability of this material to operate directly with simulated biogas mixtures without loss of single cell performance due to the formation of carbon deposits or sulphur anode poisoning. The activity of this material for the exothermic oxidation of methane reduces the energy requirement of the endothermic internal methane reforming process. The cobalt doping of basic copper–ceria formulation enhanced sulphur and carbon coking tolerance of the SOFC anode material. 相似文献
93.
H. Monzón M.A. Laguna-Bercero A. Larrea B.I. Arias A. Várez B. Levenfeld 《International Journal of Hydrogen Energy》2014
The current work describes the adaptation of an existing lab-scale cell production method for an anode supported microtubular solid oxide fuel cell to an industrially ready and easily scalable method using extruded supports. For this purpose, Ni–YSZ (yttria stabilized zirconia) anode is firstly manufactured by Powder Extrusion Moulding (PEM). Feedstock composition, extruding parameters and binder removal procedure are adapted to obtain the tubular supports. The final conditions for this process were: feedstock solid load of 65 vol%; a combination of solvent debinding in heptane and thermal debinding at 600 °C. Subsequently, the YSZ electrolyte layer is deposited by dip coating and the sintering parameters are optimized to achieve a dense layer at 1500 °C during 2 h. For the cathode, an LSM (lanthanum strontium manganite)–YSZ layer with an active area of ∼1 cm2 is deposited by dip coating. Finally, the electrochemical performance of the cell is measured using pure humidified hydrogen as fuel. The measured power density of the cell at 0.5 V was 0.7 W cm−2 at 850 °C. 相似文献
94.
Triplet nano-composite electrodes are actively examined experimentally, but there is a shortage of theoretical study. Theoretical models are helpful for understanding the experiments and provide guidance for design optimization of the novel electrode. Here new models for computing the electrode electronic and ionic conductivities, TPB length and hydraulic radius are presented. The novel properties determined by the models are used in a multi-physics numerical model that couples the intricate interdependency among electric conductions, electrochemical reaction and gas transport in SOFC. The theoretical I–V relations and hydraulic radius are in good agreement with the experiments, validatingtheproposed property models. The property models are then used to examine the influence of microstructure and material composition. The results show that: (i) Larger core-particle size and smaller nano-particle size are helpful for improving electrode properties; (ii) The required nano-particle loading is determined by the desired electronic conductivity instead of the desired TPB length. 相似文献
95.
Development and characterization of vacuum plasma sprayed thin film solid oxide fuel cells 总被引:5,自引:0,他引:5
The vacuum plasma spraying (VPS) process allows the production of thin solid oxide fuel cells (SOFCs) with low internal resistances.
This enables the reduction of the cell operating temperature without a significant decrease in power density. Consequently,
the long-term stability of the cells can be improved and low-cost materials can be used.
Different material combinations and spray parameter variations were applied to develop thin-film SOFCs, which were plasma
sprayed in a consecutive deposition process onto different porous metallic substrates. The use of Laval nozzles, which were
developed at the German Aerospace Center (DLR), and the use of conical F4V standard nozzles enable the fabrication of thin
gas tight yttria- and scandia-stabilized ZrO2 (YSZ and ScSZ) electrolyte layers and of porous electrode layers with high material deposition rates. The optimization of
the VPS parameters has been supported by laser doppler anemometry (LDA) investigations.
The development of the plasma-sprayed cells with a total thickness of approximately 100 μm requires an overall electrical
and electrochemical characterization process of the single layers and of the completely plasma-sprayed cell assembly. The
plasma-sprayed cell layers reveal high electrical conductivities. The plasma-sprayed cells show very good electrochemical
performance and low internal resistances. Power densities of 300 to 400 mW/cm2 at low operating temperatures of 750 to 800 °C were achieved. These cells can be assembled to high performance SOFC stacks
with active cell areas up to 400 cm2, which can be operated at reduced temperatures and good long-term stability. 相似文献
96.
Combinations of two or four trivalent oxides were substituted for gadolinia up to 5 mol% in the 20 mol% gadolinia-doped ceria
electrolyte as additional dopants. Most of them increased the electrical conductivity of the electrolyte but some did not.
Among them (YLa)0.01Gd0.19Ce0.8O1.9 and (YSm)0.03Gd0.17Ce0.8O1.9 showed the highest electrical conductivities, respectively, at 800 ‡C and 600 ‡C. These experimental results were analyzed
in terms of activation enthalpy and entropy for ionic conduction. Among the various possible contributions to the activation
entropy, only the configurational entropy was taken into account for the explanation. 相似文献
97.
98.
Yttria stabilized zirconia (YSZ) has widely been used as an electrolyte in solid oxide fuel cell (SOFC) stacks. The microstructure and properties of YSZ related to the fabrication process are discussed in this paper. For the named two-step sintering process, uniform and hexagonal grains with a size of 1–4 μm were obtained from the adobe following tape calendaring (TCL). Elliptical and hexagonal grains with a size of 0.4–3 μm were obtained from the adobe of tape casting (TCS) using the three-step process. The electrical conductivities of YSZ with different grain sizes were measured via the four-probe DC technique and grain conductivities and grain boundary conductivities of YSZ were investigated by impedance spectroscopy. YSZ electrolytes with a grain size of 0.1–0.4 μm had the highest electrical conductivity in the range of 500–1000 °C, especially at medium and low temperatures 550–800 °C. As the YSZ grain size becomes small, the thickness of the intergranular region decreased greatly. The YSZ electrolytes with sub-micrometer grain sizes, high ion conductivity and low sintering temperatures are important to the electrode-supported SOFC, on which the dense YSZ electrolyte films are optimized at 10 μm. 相似文献
99.
Solid oxide fuel cells (SOFCs) that can operate directly on hydrocarbon fuels, without external reforming, have the potential of greatly speeding up the application of SOFCs for transportation and distributed-power supplies. In this paper, a dual tape casting method for fabricating an anode-supported thin-electrolyte (scandia stabilized zirconia (ScSZ)) film and SOFCs that are active for the oxidation of wet ethanol was presented. The fabrication method relies upon the inclusion of ammonium oxalate ((NH4)2C2O4·H2O) pore formers in the anode green tape in order to produce a porous ScSZ matrix, which forms the anode after wet impregnation with aqueous solutions of Cu(NO3)2 and Ce(NO3)3, and firing. Anodes with different ratios of copper to ceria but with the same total loading were fabricated and measured. The performance characteristics for such cells were studied in both H2 and C2H5OH + H2O, for comparison, and the long-term performance of the cells in C2H5OH stream at 800 °C was also presented. 相似文献
100.
《International Journal of Hydrogen Energy》2019,44(16):8493-8501
Solid oxide fuel cell is a promising technology to convert renewable energy sources to electricity electrochemically at high efficiencies, thus an important applied research topic worldwide. The in-house developed so-called F-stack-design aims at stationary applications and can achieve a very long lifetime. However, since production costs should be reduced, one research focus lies on finding suitable less expensive materials. Therefore, alternatives for the benchmark Ni-mesh as anode contacting element in the stack were studied. Several types of Ni-coated-steels were tested in a stack. After 3000 h of operation the different anode contact materials are compared with the Ni-mesh in terms of microstructure as well as chemical composition. A discussion of the results is given. 相似文献