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Sample records for cells sofc anodes

  1. Effect of interlayer on structure and performance of anode-supported SOFC single cells

    International Nuclear Information System (INIS)

    Eom, Tae Wook; Yang, Hae Kwang; Kim, Kyung Hwan; Yoon, Hyon Hee; Kim, Jong Sung; Park, Sang Joon

    2008-01-01

    To lower the operating temperatures in solid oxide fuel cell (SOFC) operations, anode-supported SOFC single cells with a single dip-coated interlayer were fabricated and the effect of the interlayer on the electrolyte structure and the electrical performance was investigated. For the preparation of SOFC single cells, yttria-stabilized zirconia (YSZ) electrolyte, NiO-YSZ anode, and 50% YSZ-50% strontium-doped lanthanum manganite (LSM) cathode were used. In order to characterize the cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized and the gas (air) permeability measurements were conducted for gas tightness estimation. When the interlayer was inserted onto NiO-YSZ anode, the surface roughness of anode was diminished by about 40% and dense crack-free electrolytes were obtained. The electrical performance was enhanced remarkably and the maximum power density was 0.57 W/cm 2 at 800 deg. C and 0.44 W/cm 2 at 700 deg. C. On the other hand, the effect of interlayer on the gas tightness was negligible. The characterization study revealed that the enhancement in the electrical performance was mainly attributed to the increase of ion transmission area of anode/electrolyte interface and the increase of ionic conductivity of dense crack-free electrolyte layer

  2. Full Ceramic Fuel Cells Based on Strontium Titanate Anodes, An Approach Towards More Robust SOFCs

    DEFF Research Database (Denmark)

    Holtappels, Peter; Irvine, J.T.S.; Iwanschitz, B.

    2013-01-01

    The persistent problems with Ni-YSZ cermet based SOFCs, with respect to redox stability and tolerance towards sulfur has stimulated the development of a full ceramic cell based on strontium titanate(ST)- based anodes and anode support materials, within the EU FCH JU project SCOTAS-SOFC. Three...

  3. In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

    KAUST Repository

    Maher, R. C.; Duboviks, V.; Offer, G.; Cohen, L. F.; Brandon, N. P.

    2013-01-01

    Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

  4. In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

    KAUST Repository

    Maher, R. C.

    2013-10-06

    Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

  5. SOFC anode reduction studied by in situ TEM

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Wagner, Jakob Birkedal; Hansen, Thomas Willum

    The Solid Oxide Fuel Cell (SOFC) is a promising part of future energy approaches due to a relatively high energy conversion efficiency and low environmental pollution. SOFCs are typically composed of ceramic materials which are highly complex at the nanoscale. TEM is routinely applied ex situ...... for studying these nanoscale structures, but only few SOFC studies have applied in situ TEM to observe the ceramic nanostructures in a reactive gas environment at elevated temperatures. The present contribution focuses on the reduction of an SOFC anode which is a necessary process to form the catalytically...... active Ni surface before operating the fuel cells. The reduction process was followed in the TEM while exposing a NiO/YSZ (YSZ = Y2O3-stabilized ZrO2) model anode to H2 at T = 250-1000⁰C. Pure NiO was used in reference experiments. Previous studies have shown that the reduction of pure Ni...

  6. Multilayer tape cast SOFC – Effect of anode sintering temperature

    DEFF Research Database (Denmark)

    Hauch, Anne; Birkl, Christoph; Brodersen, Karen

    2012-01-01

    Multilayer tape casting (MTC) is considered a promising, cost-efficient, up-scalable shaping process for production of planar anode supported solid oxide fuel cells (SOFC). Multilayer tape casting of the three layers comprising the half cell (anode support/active anode/electrolyte) can potentially...

  7. Manufacturing of anode supported SOFCs: Processing parameters and their influence

    DEFF Research Database (Denmark)

    Ramousse, Severine; Menon, Mohan; Brodersen, Karen

    2007-01-01

    The establishment of low cost, highly reliable and reproducible manufacturing processes has been focused for commercialization of SOFC technology. A major challenge in the production chain is the manufacture of anode-supported planar SOFC's single cells in which each layer in a layered structure...... contains a complex microstructure. In order to improve the cell performance as well as reducing the processing costs, it has been found necessary to consider the process chain holistically, because successful manufacture of such a cell and the achievement of optimal final properties depend on each...... of the processing steps and their interdependence. A large database for several thousand anode-supported SOFCs manufactured annually at the Risoe National Laboratory in collaboration with Topsoe Fuel Cell A/S has been constructed. This enables a statistical analysis of the various controlling parameters. Some...

  8. Study of Internal and External Leaks in Tests of Anode-Supported SOFCs

    DEFF Research Database (Denmark)

    Rasmussen, Jens Foldager Bregnballe; Hendriksen, Peter Vang; Hagen, Anke

    2008-01-01

    A planar anode-supported solid oxide fuel cell (SOFC) has been tested to investigate gas tightness of the electrolyte and the applied seals. Gas leaks reduce the efficiency of the SOFC and it is thus important to determine and minimise them. Probe gases (He and Ar) and a Quadrupole Mass Spectrome......A planar anode-supported solid oxide fuel cell (SOFC) has been tested to investigate gas tightness of the electrolyte and the applied seals. Gas leaks reduce the efficiency of the SOFC and it is thus important to determine and minimise them. Probe gases (He and Ar) and a Quadrupole Mass...... Spectrometer were used to detect both internal (through electrolyte) and external (through seals) gas leaks. The internal gas leak through the electrolyte was quantified under different conditions, as was the external leak from the surroundings to the anode. The internal gas leak did not depend on the pressure...... difference between the anode and the cathode gas compartment, and can thus be described as diffusion driven. External leaks between the surroundings and the anode, but not the cathode gas compartment was observed. They were influenced by the pressure difference and are thus driven by both concentration...

  9. Interfacial layers in tape cast anode-supported doped lanthanum gallate SOFC elements

    Energy Technology Data Exchange (ETDEWEB)

    Maffei, N.; De Silveira, G. [Materials Technology Laboratory, Natural Resources Canada, CANMET, 405 Rochester Street, Ottawa, Ontario (Canada) K1A OG3

    2003-04-01

    Lanthanum gallate doped with strontium and magnesium (LSGM) is a promising electrolyte system for intermediate temperature solid oxide fuel cells (SOFCs). The reported formation of interfacial layers in monolithic type SOFCs based on lanthanum gallate is of concern because of its impact on the performance of the fuel cell. Planar anode-supported SOFC elements (without the cathode) were prepared by the tape casting technique in order to determine the nature of the anode/electrolyte interface after sintering. Two anode systems were studied, one a NiO-CeO{sub 2} cermet, and the other, a modified lanthanum gallate anode containing manganese. Sintering studies were conducted at 1250, 1300, 1350, 1400 and 1450 C to determine the effect of temperature on the interfacial characteristics. Scanning electron microscopy (SEM) revealed a significant diffusion of Ni from the NiO-CeO{sub 2} anode resulting in the formation of an interfacial layer regardless of sintering temperature. Significant La diffusion from the electrolyte into the anode was also observed. In the case of the modified lanthanum gallate anode containing manganese, there was no interfacial layer formation, but a significant diffusion of Mn into the electrolyte was observed.

  10. Perovskites synthesis to SOFC anodes

    International Nuclear Information System (INIS)

    Wendler, L.P.; Chinelatto, A.L.; Chinelatto, A.S.A.; Ramos, K.

    2012-01-01

    Perovskite structure materials containing lanthanum have been widely applied as solid oxide fuel cells (SOFCs) electrodes, due to its electrical properties. Was investigated the obtain of the perovskite structure LaCr 0,5 Ni 0,5 O 3 , by Pechini method, and its suitability as SOFC anode. The choice of this composition was based on the stability provided by chromium and the catalytic properties of nickel. After preparing the resins, the samples were calcined at 300 deg C, 600 deg C, 700 deg C and 850 deg C. The resulting powders were characterized by X-ray diffraction to determine the existing phases. Furthermore, were performed other analysis, like X-ray fluorescence, He pycnometry, specific surface area by BET isotherm and scanning electronic microscopy (author)

  11. Realisation of an anode supported planar SOFC system

    Energy Technology Data Exchange (ETDEWEB)

    Buchkremer, H.P.; Stoever, D. [Institut fuer Werkstoffe der Energietechnik, Juelich (Germany); Diekmann, U. [Zentralabteilung Technologie, Juelich (Germany)] [and others

    1996-12-31

    Lowering the operating temperature of S0FCs to below 800{degrees}C potentially lowers production costs of a SOFC system because of a less expensive periphery and is able to guarantee sufficient life time of the stack. One way of achieving lower operating temperatures is the development of new high conductive electrolyte materials. The other way, still based on state-of-the-art material, i.e. yttria-stabilized zirconia (YSZ) electrolyte, is the development of a thin film electrolyte concept. In the Forschungszentrum Julich a program was started to produce a supported planar SOFC with an YSZ electrolyte thickness between 10 to 20 put. One of the electrodes, i.e. the anode, was used as support, in order not to increase the number of components in the SOFC. The high electronic conductivity of the anode-cermet allows the use of relatively thick layers without increasing the cell resistance. An additional advantage of the supported planar concept is the possibility to produce single cells larger than 10 x 10 cm x cm, that is with an effective electrode cross area of several hundred cm{sup 2}.

  12. Study of Operating Parameters for Accelerated Anode Degradation in SOFCs

    DEFF Research Database (Denmark)

    Ploner, Alexandra; Hagen, Anke; Hauch, Anne

    2017-01-01

    Solid oxide fuel cell (SOFC) applications require lifetimes of several years on the system level. A big challenge is to demonstrate such exceptionally long lifetimes in ongoing R&D projects. Accelerated or compressed testing are alternative methods to obtain this. Activities in this area have been...... carried out without arriving at a generally accepted methodology. This is mainly due to the complexity of degradation mechanisms on the single SOFC components as function of operating parameters. In this study, we present a detailed analysis of approx. 180 durability tests regarding degradation of single...... SOFC components as function of operating conditions. Electrochemical impedance data were collected on the fresh and long-term tested SOFCs and used to de-convolute the individual losses of single SOFC cell components – electrolyte, cathode and anode. The main findings include a time-dependent effect...

  13. In-Situ Optical Studies of Oxidation/Reduction Kinetics on SOFC Cermet Anodes

    Science.gov (United States)

    2010-12-28

    DATES COVERED (From - To) 1/29/10-9/30/10 4. TITLE AND SUBTITLE In situ optical studies of oxidation/reduction kinetics on SOFC cermet anodes 5a...0572 In-situ Optical Studies of Oxidation/Reduction Kinetics on SOFC Cermet Anodes Department of Chemistry and Biochemistry Montana State University...of Research In-situ Optical Studies of Oxidation/Reduction Kinetics on SOFC Cermet Anodes Principal Investigator Robert Walker Organization

  14. Comparison of the Degradation of the Polarization Resistance of Symmetrical LSM-YSZ Cells, with Anode Supported Ni-YSZ/YSZ/LSM-YSZ SOFCs

    DEFF Research Database (Denmark)

    Torres da Silva, Iris Maura; Nielsen, Jimmi; Hjelm, Johan

    2009-01-01

    Impedance spectra of a symmetrical cell with SOFC cathodes (LSM-YSZ/YSZ/LSM-YSZ) and an anode supported planar SOFC (Ni-YSZ/YSZ/LSM-YSZ) were collected at OCV at 650{degree sign}C in air (cathode) and humidified (4%) hydrogen (anode), over 155 hours. The impedance was affected by degradation over...... time in the same frequency range for both cells (~10 Hz), possibly indicating that the same physical process was affected in both types of cell. However, deconvolution of the impedance data was not straightforward. When n-values of the constant phase elements in the otherwise identical equivalent...

  15. Solid Oxide Fuel Cell (SOFC) Development in Denmark

    DEFF Research Database (Denmark)

    Linderoth, Søren; Larsen, Peter Halvor; Mogensen, Mogens Bjerg

    2007-01-01

    on larger anode-supported cells as well as a new generation of SOFCs based on porous metal supports and new electrode and electrolyte materials. The SOFC program comprises development of next generation of cells and multi stack modules for operation at lower temperature with increased durability...

  16. Direct Utilization of Liquid Fuels in SOFC for Portable Applications: Challenges for the Selection of Alternative Anodes

    Directory of Open Access Journals (Sweden)

    Massimiliano Cimenti

    2009-06-01

    Full Text Available Solid oxide fuel cells (SOFC have the advantage of being able to operate with fuels other than hydrogen. In particular, liquid fuels are especially attractive for powering portable applications such as small power generators or auxiliary power units, in which case the direct utilization of the fuel would be convenient. Although liquid fuels are easier to handle and transport than hydrogen, their direct use in SOFC can lead to anode deactivation due to carbon formation, especially on traditional nickel/yttria stabilized zirconia (Ni/YSZ anodes. Significant advances have been made in anodic materials that are resistant to carbon formation but often these materials are less electrochemically active than Ni/YSZ. In this review the challenges of using liquid fuels directly in SOFC, in terms of gas-phase and catalytic reactions within the anode chamber, will be discussed and the alternative anode materials so far investigated will be compared.

  17. The mechanism behind redox instability of anodes in high-temperature SOFCs

    DEFF Research Database (Denmark)

    Klemensø, Trine; Chung, Charissa; Larsen, Peter Halvor

    2005-01-01

    Bulk expansion of the anode upon oxidation is considered to be responsible for the lack of redox stability in high-temperature solid oxide fuel cells (SOFCs). The bulk expansion of nickel-yttria stabilized zirconia (YSZ) anode materials was measured by dilatometry as a function of sample geometry......, ceramic component, temperature, and temperature cycling. The strength of the ceramic network and the degree of Ni redistribution appeared to be key parameters of the redox behavior. A model of the redox mechanism in nickel-YSZ anodes was developed based on the dilatometry data and macro...

  18. Infiltrated SrTiO3:FeCr‐based Anodes for Metal‐Supported SOFC

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Reddy Sudireddy, Bhaskar; Persson, Åsa Helen

    2013-01-01

    The concept of using electronically conducting anode backbones with subsequent infiltration of electrocatalytic active materials has been used to develop an alternative solid oxide fuel cell (SOFC) design based on a ferritic stainless steel support. The anode backbone consists of a composite made...

  19. Poisoning of Ni-Based anode for proton conducting SOFC by H2S, CO2, and H2O as fuel contaminants

    Science.gov (United States)

    Sun, Shichen; Awadallah, Osama; Cheng, Zhe

    2018-02-01

    It is well known that conventional solid oxide fuel cells (SOFCs) based on oxide ion conducting electrolyte (e.g., yttria-stabilized zirconia, YSZ) and nickel (Ni) - ceramic cermet anodes are susceptible to poisoning by trace amount of hydrogen sulfide (H2S) while not significantly impacted by the presence of carbon dioxide (CO2) and moisture (H2O) in the fuel stream unless under extreme operating conditions. In comparison, the impacts of H2S, CO2, and H2O on proton-conducting SOFCs remain largely unexplored. This study aims at revealing the poisoning behaviors caused by H2S, CO2, and H2O for proton-conducting SOFCs. Anode-supported proton-conducting SOFCs with BaZe0.1Ce0.7Y0.1Yb0.1O3 (BZCYYb) electrolyte and Ni-BZCYYb anode and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode as well as Ni-BZCYYb/BZCYYb/Ni-BZCYYb anode symmetrical cells were subjected to low ppm-level H2S or low percentage-level CO2 or H2O in the hydrogen fuel, and the responses in cell electrochemical behaviors were recorded. The results suggest that, contrary to conventional SOFCs that show sulfur poisoning and CO2 and H2O tolerance, such proton-conducting SOFCs with Ni-BZCYYb cermet anode seem to be poisoned by all three types of "contaminants". Beyond that, the implications of the experimental observations on understanding the fundamental mechanism of anode hydrogen electrochemical oxidation reaction in proton conducting SOFCs are also discussed.

  20. Niobium-doped strontium titanates as SOFC anodes

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Kammer Hansen, Kent; Wallenberg, L. Reine

    2008-01-01

    been synthesized with a recently developed modified glycine-nitrate process. The synthesized powders have been calcined and sintered in air or in 9% H(2) / N(2) between 800 - 1400 degrees C. After calcination the samples were single phase Nb-doped strontium titanate with grain sizes of less than 100 nm...... in diameter on average. The phase purity, defect structure, and microstructure of the materials have been analyzed with SEM, XRD, and TGA. The electrical conductivity of the Nb-doped titanate decreased with increasing temperature and showed a phonon scattering conduction mechanism with sigma > 120 S...... ability of the Nb-doped titanates to be used as a part of a SOFC anode. However, the catalytic activity of the materials was not sufficient and it needs to be improved if titanate based materials are to be realized as constituents in SOFC anodes....

  1. Redox Stable Anodes for Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Guoliang eXiao

    2014-06-01

    Full Text Available Solid oxide fuel cells (SOFCs can convert chemical energy from the fuel directly to electrical energy with high efficiency and fuel flexibility. Ni-based cermets have been the most widely adopted anode for SOFCs. However, the conventional Ni-based anode has low tolerance to sulfur-contamination, is vulnerable to deactivation by carbon build-up (coking from direct oxidation of hydrocarbon fuels, and suffers volume instability upon redox cycling. Among these limitations, the redox instability of the anode is particularly important and has been intensively studied since the SOFC anode may experience redox cycling during fuel cell operations even with the ideal pure hydrogen as the fuel. This review aims to highlight recent progresses on improving redox stability of the conventional Ni-based anode through microstructure optimization and exploration of alternative ceramic-based anode materials.

  2. Effect of Samarium Oxide on the Electrical Conductivity of Plasma-Sprayed SOFC Anodes

    Science.gov (United States)

    Panahi, S. N.; Samadi, H.; Nemati, A.

    2016-10-01

    Solid oxide fuel cells (SOFCs) are rapidly becoming recognized as a new alternative to traditional energy conversion systems because of their high energy efficiency. From an ecological perspective, this environmentally friendly technology, which produces clean energy, is likely to be implemented more frequently in the future. However, the current SOFC technology still cannot meet the demands of commercial applications due to temperature constraints and high cost. To develop a marketable SOFC, suppliers have tended to reduce the operating temperatures by a few hundred degrees. The overall trend for SOFC materials is to reduce their service temperature of electrolyte. Meanwhile, it is important that the other components perform at the same temperature. Currently, the anodes of SOFCs are being studied in depth. Research has indicated that anodes based on a perovskite structure are a more promising candidate in SOFCs than the traditional system because they possess more favorable electrical properties. Among the perovskite-type oxides, SrTiO3 is one of the most promising compositions, with studies demonstrating that SrTiO3 exhibits particularly favorable electrical properties in contrast with other perovskite-type oxides. The main purpose of this article is to describe our study of the effect of rare-earth dopants with a perovskite structure on the electrical behavior of anodes in SOFCs. Sm2O3-doped SrTiO3 synthesized by a solid-state reaction was coated on substrate by atmospheric plasma spray. To compare the effect of the dopant on the electrical conductivity of strontium titanate, different concentrations of Sm2O3 were used. The samples were then investigated by x-ray diffraction, four-point probe at various temperatures (to determine the electrical conductivity), and a scanning electron microscope. The study showed that at room temperature, nondoped samples have a higher electrical resistance than doped samples. As the temperature was increased, the electrical

  3. In situ observations of microstructural changes in SOFC anodes during redox cycling

    DEFF Research Database (Denmark)

    Klemensø, Trine; Appel, C. C.; Mogensen, Mogens Bjerg

    2006-01-01

    The anode-supported solid oxide fuel cell (SOFC) degrades when the anode is subjected to redox cycling. The degradation has qualitatively been related to microstructural changes in the nickel-yttria stabilized zirconia anode of the tested cells. In this work, the microstructural changes were...... observed in situ using environmental scanning electron microscopy. In the reduced state, a dynamic rounding of the nickel particles occurred. The oxide growth upon re-oxidation depended on the oxidation kinetics. During rapid oxidation, the NiO particles divided into 2-4 particles, which grew...... into the surrounding voids. For slower oxidation, an external oxide layer was seen to develop around the individual particles. (c) 2006 The Electrochemical Society....

  4. Development of solid oxide fuel cells; Desenvolvimento de celulas a combustivel do tipo oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Boaventura, Jaime S.; Alencar, Marcelo Goncalves F. de; Amaral, Alexandre Alves do; Benedicto, Joao Paulo Santos; Silva, Marcos A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Dept. de Fisico-Quimica

    2006-07-01

    Fuel cells allow the energy production without the thermodynamic restriction of the conversion of heat into work. Among their various types, the solid oxide fuel cells (SOFC), operating at high temperatures, allow the methane conversion into electricity directly on the anode. The main element of the SOFC is the structure A/E/C: anode/electrolyte/cathode, all sintered at high temperature as resistant ceramic materials. Dense electrolyte (YSZ: zirconia stabilized for Yttria) separates the anode (Ni+Co/YSZ: cobalt promoted nickel, supported on YSZ) and cathode (LSM: strontium-doped lanthanum manganite), both with porosity obtained by graphite addition. To obtain suitable A/E/C pellets, the layer sintering with appropriate mechanical and textural characteristics is essential, requiring excellent electric junctions between them. The cell performance has been evaluated between 850 and 950 degree C, using hydrogen or methane fuel; the tension and current for different resistance values in the electrical circuit have been measured. The cobalt addition to the cell anode significantly increased its activity for the reform reaction. The beneficial effect was probably due to the easier nickel reduction in cobalt presence. This work had the objectives of developing and evaluating electro-catalysts, as well as the solid oxide fuel cells using these catalysts as anode. Five SOFC models (SOFC 1 to SOFC 5) are described; all of them were developed aiming at improving the preparation of the anode/electrolyte/cathode structure (A/E/C). (author)

  5. High temperature phase transition in SOFC anodes based on Sr2MgMoO6-δ

    International Nuclear Information System (INIS)

    Marrero-Lopez, D.; Pena-Martinez, J.; Ruiz-Morales, J.C.; Martin-Sedeno, M.C.; Nunez, P.

    2009-01-01

    The double perovskite Sr 2 MgMoO 6-δ has been recently reported as an efficient anode material for solid oxide fuel cells (SOFCs). In the present work, this material have been investigated by high temperature X-ray diffraction (XRD), differential scanning calorimetry (DSC) and impedance spectroscopy to further characterise its properties as SOFC anode. DSC and XRD measurements indicate that Sr 2 MgMoO 6-δ exhibits a reversible phase transition around 275 deg. C from triclinic (I1-bar) with an octahedral tilting distortion to cubic (Fm3-barm) without octahedral distortion. This phase transition is continuous with increasing temperature without any sudden cell volume change during the phase transformation. The main effect of the phase transformation is observed in the electrical conductivity with a change in the activation energy at low temperature. La 3+ and Fe-substituted Sr 2 MgMoO 6-δ phases were also investigated, however these materials are unstable under oxidising conditions due to phase segregations above 600 deg. C. - Graphical abstract: The double perovskite Sr 2 MgMoO 6 , recently proposed as an efficient SOFC anode for direct hydrocarbon oxidation, exhibits a reversible structural phase transition from triclinic to cubic at 275 deg. C.

  6. Performance-Microstructure Relations in Ni/CGO Infiltrated Nb-doped SrTiO3 SOFC Anodes

    DEFF Research Database (Denmark)

    Ramos, Tania; Bernuy-Lopez, Carlos; Reddy Sudireddy, Bhaskar

    2012-01-01

    Nb-doped SrTiO3 solid oxide fuel cell (SOFC) anodes, infiltrated with CGO/Ni, were investigated by electrochemical impedance spectroscopy (EIS) and high resolution microscopy techniques, upon varying production and testing parameters. The electrochemical analysis involved a combination of distrib......Nb-doped SrTiO3 solid oxide fuel cell (SOFC) anodes, infiltrated with CGO/Ni, were investigated by electrochemical impedance spectroscopy (EIS) and high resolution microscopy techniques, upon varying production and testing parameters. The electrochemical analysis involved a combination...... of distribution of relaxation times (DRT) and complex non-linear least squares (CNLS) fitting routine. These electrodes were studied as singlephase or as composites with 8YSZ. Sr0.94Ti0.9Nb0.1O3-δ/ 10 vol.% 8YSZ composite infiltrated electrodes were the best overall performers, with enhanced performance stability...

  7. Fuel cell: new electrocatalysts for SOFC (Solid Oxide Fuel Cells) anodes and regulation between cell performance and catalytic activity; Celula a combustivel: novos eletrocatalisadores para anodos de SOFC (Celulas a Combustivel de Oxido Solido) e correlacao entre desempenho da celula e atividade catalitica

    Energy Technology Data Exchange (ETDEWEB)

    Boaventura, Jaime S.; Aguiar, Aurinete B.; Brandao, Soraia T. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Frank, Maria Helena Troise; Campos, Michel F. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    Electro-catalysts were prepared using new routes. Chemical Ultrasound Deposition (CUD) method: aqueous solution of nickel nitrate and citric acid was ultrasound vaporized and deposited on heated Ytria-stabilized Zirconia (YSZ). Resin impregnation (IPR) method: nickel oxide and YSZ were mixed, added to phenolic resins, precipitated in acidic water and milled. Wet impregnation method (IMP) was used for comparison: YSZ and an aqueous solution of nickel nitrate and citric acid were mixed, followed by evaporation, drying and calcination. The catalysts were evaluated for methane steam reforming in a quartz reactor. The reactions were conducted for one hour with no significant catalytic activity loss. In reactions with 100 mg of catalyst and a mixture consisting of methane and steam (3:1), IPR catalyst showed activity higher and better stability than those by IMP. On other tests, the reform was conducted with 100 mg of catalyst and methane to steam of 10. The IPR catalyst activity was so high that the reaction approached equilibrium conditions. Anode/electrolyte/cathode units (A/E/C) were prepared with the above catalysts as follows: the anode was a catalyst porous layer; the electrolyte an YSZ dense layer; and the cathode an LSM porous layer; graphite powder formed the material porosity. The two first layers, in powder form, were put in a stainless steel cast, pressed to 4000 bars and sinterized. The cathode layer was subsequently added using tape-casting techniques followed by sintering. A/E/C units showed 40% linear contraction and porosity higher than 20%. For fuel cell tests, A/E/C was mounted in alumina plates with platinum current collectors. Unitary SOF cells were loaded with hydrogen diluted in nitrogen showing opened circuit voltage from circa 700 mV, for the CUD anode, to 350 mV, for the IPR anode. The unitary SOFC was loaded with methane for 15 minutes or longer, with no noticeable voltage loss. At 1300 K the SOFC made with IPR or IMP catalysts showed opened

  8. Electro-catalysts for hydrogen production from ethanol for use in SOFC anodes

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcos Aurelio da; Paz Fiuza, Raigenis da; Guedes, Bruna C.; Pontes, Luiz A.; Boaventura, Jaime Soares [UFBA, Salvador, Bahia (Brazil). Energy and Materials Science Group

    2010-07-01

    Nickel and cobalt catalysts, supported on YSZ, were prepared by wet impregnation, with and without citric acid; the metal load was 10 and 35% by weight. The catalyst composition was studied by XRF, XPS and SEM-EDS. At low metal concentration, the results of these techniques presented comparables figures; at high concentration, SEM-EDS suggested a non-uniform distribution. The analysis showed that the solids were mixed oxides and formed an alloy after reduction. The surface passivation was possible under controlled conditions. The catalytic test with the steam reforming of ethanol indicated that the metal load had almost no effect on the catalytic activity, but decreased its selectivity. Afterwards, a unitary SOFC was prepared with deposition of the cathode layer. AFM and EIS were used for the characterization of SOFC components. They showed that the electro-catalyst surface was almost all covered with the metal phase, including the large pore walls of the anode. The YSZ phase dominates the material conductance of the complete SOFC assembly (anode/electrolyte/cathode). The unitary SOFC was tested with hydrogen, gaseous ethanol or natural gas; the SOFC operating with ethanol and hydrogen fuel presented virtually no over-potential. (orig.)

  9. Robust automatic high resolution segmentation of SOFC anode porosity in 3D

    DEFF Research Database (Denmark)

    Jørgensen, Peter Stanley; Bowen, Jacob R.

    2008-01-01

    Routine use of 3D characterization of SOFCs by focused ion beam (FIB) serial sectioning is generally restricted by the time consuming task of manually delineating structures within each image slice. We apply advanced image analysis algorithms to automatically segment the porosity phase of an SOFC...... anode in 3D. The technique is based on numerical approximations to partial differential equations to evolve a 3D surface to the desired phase boundary. Vector fields derived from the experimentally acquired data are used as the driving force. The automatic segmentation compared to manual delineation...... reveals and good correspondence and the two approaches are quantitatively compared. It is concluded that the. automatic approach is more robust, more reproduceable and orders of magnitude quicker than manual segmentation of SOFC anode porosity for subsequent quantitative 3D analysis. Lastly...

  10. Ag as an alternative for Ni in direct hydrocarbon SOFC anodes

    Energy Technology Data Exchange (ETDEWEB)

    Cantos-Gomez, A.; Van Duijn, J. [Instituto de Energias Renovables, Universidad de Castilla La Mancha, Paseo de la Investigacion 1, 02006 Albacete (Spain); Ruiz-Bustos, R. [Instituto de Energias Renovables, Parque Cientifico y Tecnologico de Albacete, Paseo de la Investigacion 1, 02006 Albacete (Spain)

    2011-02-15

    Ag has been shown to be a good metal for SOFC anode cermets using CO fuel. Here we have expanded on the work reported by testing Ag-YSZ cermets against different hydrocarbon based fuel (H{sub 2} and CH{sub 4}). This study shows that while Ag is a good current collector, it alone does not have the required catalytic activity for the direct oxidation of hydrocarbon based fuels needed to be used in SOFC anodes. As such an additional catalytic material (e.g. CeO{sub 2}) needs to be present when using fuels other then CO. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Effects of Pretreatment Methods on Electrodes and SOFC Performance

    Directory of Open Access Journals (Sweden)

    Guo-Bin Jung

    2014-06-01

    Full Text Available Commercially available tapes (anode, electrolyte and paste (cathode were choosen to prepare anode-supported cells for solid oxide fuel cell applications. For both anode-supported cells or electrolyte-supported cells, the anode needs pretreatment to reduce NiO/YSZ to Ni/YSZ to increase its conductivity as well as its catalytic characteristics. In this study, the effects of different pretreatments (open-circuit, closed-circuit on cathode and anodes as well as SOFC performance are investigated. To investigate the influence of closed-circuit pretreatment on the NiO/YSZ anode alone, a Pt cathode is utilized as reference for comparison with the LSM cathode. The characterization of the electrical resistance, AC impedance, and SOFC performance of the resulting electrodes and/or anode-supported cell were carried out. It’s found that the influence of open-circuit pretreatment on the LSM cathode is limited. However, the influence of closed-circuit pretreatment on both the LSM cathode and NiO/YSZ anode and the resulting SOFC performance is profound. The effect of closed-circuit pretreatment on the NiO/YSZ anode is attributed to its change of electronic/pore structure as well as catalytic characteristics. With closed-circuit pretreatment, the SOFC performance improved greatly from the change of LSM cathode (and Pt reference compared to the Ni/YSZ anode.

  12. Anode-supported SOFC operated under single-chamber conditions at intermediate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Morales, M.; Roa, J.J.; Segarra, M. [Department of Materials Science and Metallurgical Engineering, University of Barcelona, E-08028, Barcelona (Spain); Capdevila, X.G. [Center of Design and Optimization in Avanced Materials, Parc Cientific of Barcelona, E-08028, Barcelona (Spain); Pinol, S. [Institute of Materials Science of Barcelona (CSIC), Campus of the UAB, Bellaterra E-08193, Barcelona (Spain)

    2011-02-15

    Anode-supported SOFC was fabricated using gadolinia doped ceria (GDC) as the electrolyte (15 {mu}m of thickness), Ni-GDC as the anode and La{sub 0.5}Sr{sub 0.5}CoO{sub 3-{delta}}-GDC as the cathode. Catalytic activities of the electrodes and electrical properties of the cell were determined, using mixtures of methane + air, under single-chamber conditions. This work assessed with special and wide emphasis the effect of temperature, gas composition and total flow rate on the cell performance. As a result, operational temperature range of the fuel cell was approximately between 700 and 800 C, which agrees with the results corresponding to the catalytic activities of electrodes. While Ni-GDC anode was enough active towards methane partial oxidation at cell temperatures higher than 700 C, the LSC-GDC cathode was enough inactive towards partial and total oxidation of methane at cell temperatures lower than 800 C. Under optimised gas compositions (CH{sub 4}/O{sub 2}) ratio (1) and total flow rate (530 mL min {sup -1}), power densities of 145 and 235 mW cm {sup -2} were obtained at 705 and 764 C, respectively. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Synthesis, Characterization, and Optimization of Novel Solid Oxide Fuel Cell Anodes

    Science.gov (United States)

    Miller, Elizabeth C.

    This dissertation presents research on the development of novel materials and fabrication procedures for solid oxide fuel cell (SOFC) anodes. The work discussed here is divided into three main categories: all-oxide anodes, catalyst exsolution oxide anodes, and Ni-infiltrated anodes. The all-oxide and catalyst exsolution anodes presented here are further classi?ed as Ni-free anodes operating at the standard 700-800°C SOFC temperature while the Ni-infiltrated anodes operate at intermediate temperatures (≤650°C). Compared with the current state-of-the-art Ni-based cermets, all-oxide, Ni-free SOFC anodes offer fewer coking issues in carbon-containing fuels, reduced degradation due to fuel contaminants, and improved stability during redox cycling. However, electrochemical performance has proven inferior to Ni-based anodes. The perovskite oxide Fe-substituted strontium titanate (STF) has shown potential as an anode material both as a single phase electrode and when combined with Gd-doped ceria (GDC) in a composite electrode. In this work, STF is synthesized using a modified Pechini processes with the aim of reducing STF particle size and increasing the electrochemically active area in the anode. The Pechini method produced particles ? 750 nm in diameter, which is signi°Cantly smaller than the typically micron-sized solid state reaction powder. In the first iteration of anode fabrication with the Pechini powder, issues with over-sintering of the small STF particles limited gas di?usion in the anode. However, after modifying the anode firing temperature, the Pechini cells produced power density comparable to solid state reaction based cells from previous work by Cho et al. Catalyst exsolution anodes, in which metal cations exsolve out of the lattice under reducing conditions and form nanoparticles on the oxide surface, are another Ni-free option for standard operating temperature SOFCs. Little information is known about the onset of nanoparticle formation, which

  14. Infiltrated SrTiO3:FeCr-based anodes for metalsupported SOFC

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Persson, Åsa Helen; Nielsen, Jimmi

    2012-01-01

    The concept of using highly electronically conducting backbones with subsequent infiltration of electrocatalytic active materials, has recently been used to develop an alternative SOFC design based on a ferritic stainless steel support. The metal-supported SOFC is comprised of porous and highly e...... changes occurring in the anode layer during testing. The results indicate that the STN component in the anode seems to have a positive effect on the corrosion stability of the FeCr-particles in the anode layer.......) and FeCr. Electrochemical characterization and post test SEM analysis have been used to get an insight into the possible degradation mechanisms of this novel electrode infiltrated with Gd-doped CeO2 and Ni. Accelerated oxidation/corrosion experiments have been conducted to evaluate the microstructural...

  15. Development and fabrication of a new concept planar-tubular solid oxide fuel cell (PT-SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.; Chen, F. [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026 Anhui (China); Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); Ding, D. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Gao, J. [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026 Anhui (China)

    2011-06-15

    The paper reports a new concept of planar-tubular solid oxide fuel cell (PT-SOFC). Emphasis is on the fabrication of the required complex configuration of Ni-yttria-stabilised zirconia (YSZ) porous anode support by tert-butyl alcohol (TBA) based gelcasting, particularly the effects of solid loading, amounts of monomers and dispersant on the rheological behaviour of suspension, the shrinkage of a wet gelcast green body upon drying, and the properties of final sample after sintering at 1350 C and reduction from NiO-YSZ to Ni-YSZ. The results show that the gelcasting is a powerful method for preparation of the required complex configuration anode support. The anode support resulted from an optimised suspension with the solid loading of 25 vol% has uniform microstructure with 37% porosity, bending strength of 44 MPa and conductivity of 300 S cm{sup -} {sup 1} at 700 C, meeting the requirements for an anode support of SOFC. Based on the as-prepared anode support, PT-SOFC single cell of Ni-YSZ/YSZ/LSCF has been fabricated by slurry coating and co-sintering technique. The cell peak power density reaches 63, 106 and 141 mW cm {sup -} {sup 2} at 700, 750 and 800 C, respectively, using hydrogen as fuel and ambient air as oxidant. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Impact of cell design and operating conditions on the performances of SOFC fuelled with methane

    Science.gov (United States)

    Laurencin, J.; Lefebvre-Joud, F.; Delette, G.

    An in-house-model has been developed to study the thermal and electrochemical behaviour of a planar SOFC fed directly with methane and incorporated in a boiler. The usual Ni-YSZ cermet has been considered for the anode material. It has been found that methane reforming into hydrogen occurs only at the cell inlet in a limited depth within the anode. A sensitivity analysis has allowed establishing that anode thicknesses higher than ∼400-500 μm are required to achieve both the optimal methane conversion and electrochemical performances. The direct internal reforming (DIR) mechanisms and the impact of operating conditions on temperature gradients and SOFC electrical efficiencies have been investigated considering the anode supported cell configuration. It has been shown that the temperature gradient is minimised in the autothermal mode of cell operation. Thermal equilibrium in the stack has been found to be strongly dependent on radiative heat losses with the stack envelope. Electrochemical performance and cell temperature maps have been established as a function of methane flow rates and cell voltages.

  17. Electrical Resistance Measurements and Microstructural Characterization of the Anode/Interconnect Contact in Simulated Anode-Side SOFC Conditions

    DEFF Research Database (Denmark)

    Harthøj, Anders; Alimadadi, Hossein; Holt, Tobias

    2015-01-01

    in phase transformation of the steel and in formation of oxides with a poor electrical conductivity in the anode. In this study, the area specific resistance (ASR) of the steel Crofer 22 APU, in contact with a Ni/YSZ anode with and without a tape casted CeO2 barrier layer was measured in simulated SOFC...... anode conditions at 800◦C. The microstructure in the contact area was characterized using scanning electron microscopy techniques. The ASR was low for the steel in direct contact with the Ni/YSZ anode. Nickel diffusion into the steel resulted in a fine grained zone, which was identified as ferrite...

  18. Effect of Sintering Temperature and Applied Load on Anode-Supported Electrodes for SOFC Application

    Directory of Open Access Journals (Sweden)

    Xuan-Vien Nguyen

    2016-08-01

    Full Text Available Anode-supported cells are prepared by a sequence of hot pressing and co-sintering processes for solid oxide fuel cell (SOFC applications. Commercially available porous anode tape (NiO/YSZ = 50 wt %/50 wt %, anode tape (NiO/YSZ = 30 wt %/70 wt %, and YSZ are used as the anode substrate, anode functional layer, and electrolyte layer, respectively. After hot pressing, the stacked layers are then sintered at different temperatures (1250 °C, 1350 °C, 1400 °C and 1450 °C for 5 h in air. Different compressive loads are applied during the sintering process. An (La,SrMnO3 (LSM paste is coated on the post-sintered anode-supported electrolyte surface as the cathode, and sintered at different temperatures (1100 °C, 1150 °C, 1200 °C and 1250 °C for 2 h in air to generate anode-supported cells with dimensions of 60 × 60 mm2 (active reaction area of 50 × 50 mm2. SEM is used to investigate the anode structure of the anode-supported cells. In addition, confocal laser scanning microscopy is used to investigate the roughness of the cathode surfaces. At sintering temperatures of 1400 °C and 1450 °C, there is significant grain growth in the anode. Furthermore, the surface of the cathode is smoother at a firing temperature of 1200 °C. It is also found that the optimal compressive load of 1742 Pa led to a flatness of 168 µm/6 cm and a deformation of 0.72%. The open circuit voltage and power density of the anode-supported cell at 750 °C were 1.0 V and 178 mW·cm−2, respectively.

  19. Development and testing of anode-supported solid oxide fuel cells with slurry-coated electrolyte and cathode

    Energy Technology Data Exchange (ETDEWEB)

    Muccillo, R.; Muccillo, E.N.S.; Fonseca, F.C.; Franca, Y.V.; Porfirio, T.C. [Centro de Ciencia e Tecnologia de Materiais, Instituto de Pesquisas Energeticas e Nucleares, C.P. 11049, Pinheiros, S. Paulo, SP 05422-970 (Brazil); de Florio, D.Z. [Instituto de Quimica, UNESP, R. Prof. Francisco Degni s/n, Araraquara, SP 14801-970 (Brazil); Berton, M.A.C.; Garcia, C.M. [Instituto de Tecnologia para o Desenvolvimento, DPMA, C.P. 19067, Curitiba, PR 81531-980 (Brazil)

    2006-06-01

    A laboratory setup was designed and put into operation for the development of solid oxide fuel cells (SOFCs). The whole project consisted of the preparation of the component materials: anode, cathode and electrolyte, and the buildup of a hydrogen leaking-free sample chamber with platinum leads and current collectors for measuring the electrochemical properties of single SOFCs. Several anode-supported single SOFCs of the type (ZrO{sub 2}:Y{sub 2}O{sub 3}+NiO) thick anode/(ZrO{sub 2}:Y{sub 2}O{sub 3}) thin electrolyte/(La{sub 0.65}Sr{sub 0.35}MnO{sub 3}+ZrO{sub 2}:Y{sub 2}O{sub 3}) thin cathode have been prepared and tested at 700 and 800{sup o}C after in situ H{sub 2} anode reduction. The main results show that the slurry-coating method resulted in single-cells with good reproducibility and reasonable performance, suggesting that this method can be considered for fabrication of SOFCs. (author)

  20. Control of anode supported SOFCs (solid oxide fuel cells): Part I. mathematical modeling and state estimation within one cell

    International Nuclear Information System (INIS)

    Amedi, Hamid Reza; Bazooyar, Bahamin; Pishvaie, Mahmoud Reza

    2015-01-01

    In this paper, a 3-dimensional mathematical model for one cell of an anode-supported SOFC (solid oxide fuel cells) is presented. The model is derived from the partial differential equations representing the conservation laws of ionic and electronic charges, mass, energy, and momentum. The model is implemented to fully characterize the steady state operation of the cell with countercurrent flow pattern of fuel and air. The model is also used for the comparison of countercurrent with concurrent flow patterns in terms of thermal stress (temperature distribution) and quality of operation (current density). Results reveal that the steady-state cell performance curve and output of simulations qualitatively match experimental data of the literature. Results also demonstrate that countercurrent flow pattern leads to an even distribution of temperature, more uniform current density along the cell and thus is more enduring and superior to the concurrent flow pattern. Afterward, the thorough 3-dimensional model is used for state estimation instead of a real cell. To estimate states, the model is simplified and changed to a 1-dimensional model along flow streams. This simplified model includes uncertainty (because of simplifying assumptions of the model), noise, and disturbance (because of measurements). The behaviors of extended and ensemble Kalman filter as an observer are evaluated in terms of estimating the states and filtering the noises. Results demonstrate that, like extended Kalman filter, ensemble Kalman filter properly estimates the states with 20 sets. - Highlights: • A 3-dimensional model for one cell of SOFC (solid oxide fuel cells) is presented. • Higher voltages and thermal stress in countercurrent than concurrent flow pattern. • State estimation of the cell is examined by ensemble and extended Kalman filters. • Ensemble with 20 sets is as good as extended Kalman filter.

  1. Copper based anodes for bio-ethanol fueled low-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kondakindi, R.R.; Karan, K. [Queen' s Univ., Kingston, ON (Canada)

    2003-07-01

    Laboratory studies have been conducted to develop a low-temperature solid oxide fuel cell (SOFC) fueled by bio-ethanol. SOFCs are considered to be a potential source for clean and efficient electricity. The use of bio-ethanol to power the SOFC contributes even further to reducing CO{sub 2} emissions. The main barrier towards the development of the proposed SOFC is the identification of a suitable anode catalyst that prevents coking during electro-oxidation of ethanol while yielding good electrical performance. Copper was selected as the catalyst for this study. Composite anodes consisting of copper catalysts and gadolinium-doped ceria (GDC) electrolytes were prepared using screen printing of GDC and copper oxide on dense GDC electrolytes and by wet impregnation of copper nitrate in porous GDC electrolytes followed by calcination and sintering. The electrical conductivity of the prepared anodes was characterized to determine the percolation threshold. Temperature-programmed reduction and the Brunner Emmett Teller (BET) methods were used to quantify the catalyst dispersion and surface area. Electrochemical performance of the single-cell SOFC with a hydrogen-air system was used to assess the catalytic activities. Electrochemical Impedance Spectroscopy was used to probe the electrode kinetics.

  2. In-Situ Raman Characterization of SOFC Anodes

    KAUST Repository

    Maher, Robert C.; Offer, Gregory; Brandon, Nigel P.; Cohen, Lesley F.

    2012-01-01

    Solid oxide fuel cells (SOFCs) have many advantages when compared to other fuel cell technologies, particularly for distributed stationary applications. As a consequence they are becoming ever more economically competitive with incumbent energy solutions. However, as with all technologies, improvements in durability, efficiency and cost is required before they become feasible alternatives. Such improvements are enabled through improved understanding of the critical material interactions occurring during operation. Raman spectroscopy is a noninvasive and non-destructive optical characterization tool which is ideally suited to the study of these critical chemical processes occurring within operational SOFCs. In this paper we will discuss advantages of using Raman characterization for understanding these important chemical processes occurring within SOFCs. We will present the specific examples of the type of measurement possible and discuss the direction of future research. © 2012 Materials Research Society.

  3. Anodes for Solid Oxide Fuel Cells Operating at Low Temperatures

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain

    An important issue that has limited the potential of Solid Oxide Fuel Cells (SOFCs) for portable applications is its high operating temperatures (800-1000 ºC). Lowering the operating temperature of SOFCs to 400-600 ºC enable a wider material selection, reduced degradation and increased lifetime....... On the other hand, low-temperature operation poses serious challenges to the electrode performance. Effective catalysts, redox stable electrodes with improved microstructures are the prime requisite for the development of efficient SOFC anodes. The performance of Nb-doped SrT iO3 (STN) ceramic anodes...... at 400ºC. The potential of using WO3 ceramic as an alternative anode materials has been explored. The relatively high electrode polarization resistance obtained, 11 Ohm cm2 at 600 ºC, proved the inadequate catalytic activity of this system for hydrogen oxidation. At the end of this thesis...

  4. Controlled deposition and utilization of carbon on Ni-YSZ anodes of SOFCs operating on dry methane

    International Nuclear Information System (INIS)

    Jiao, Yong; Zhang, Liqin; An, Wenting; Zhou, Wei; Sha, Yujing; Shao, Zongping; Bai, Jianping; Li, Si-Dian

    2016-01-01

    Solid oxide fuel cells (SOFCs) are promising power-generation systems to utilize methane or methane-based fuels with a high energy efficiency and low environmental impact. A successive multi-stage process is performed to explore the operation of cells using dry methane or the deposited carbon from methane decomposition as fuel. Stable operation can be maintained by optimizing the fuel supply and current density parameters. An electrochemical impedance analysis suggests that the partial oxidization of Ni can occur at anodes when the carbon fuel is consumed. The stability of cells operated on pure methane is investigated in three operating modes. The cell can run in a comparatively stable state with continuous power output in an intermittent methane supply mode, where the deposition and utilization of carbon is controlled by balancing the fuel supply and consumption. The increase in the polarization resistance of the cell might originate from the small amount of NiO and residual carbon at the anode, which can be removed via an oxidation-and-reduction maintenance process. Based on the above strategy, this work provides an alternative operating mode to improve the stability of direct methane SOFCs and demonstrates the feasibility of its application. - Highlights: • A new strategy to control the deposition and utilization of carbon was developed. • A stable fuel cell operation was obtained with an intermittent fuel supply mode. • Polarization resistance increased due to small amount of NiO and residual carbon.

  5. Fabrication and Characterization of Graded Anodes for Anode-Supported Solid Oxide Fuel Cells by Tape Casting and Lamination

    DEFF Research Database (Denmark)

    Beltran-Lopez, J.F.; Laguna-Bercero, M.A.; Gurauskis, Jonas

    2014-01-01

    Graded anodes for anode-supported solid oxide fuel cells (SOFCs) are fabricated by tape casting and subsequent cold lamination of plates using different compositions. Rheological parameters are adjusted to obtain stable suspensions for tape casting. The conditions for the tape casting and laminat......Graded anodes for anode-supported solid oxide fuel cells (SOFCs) are fabricated by tape casting and subsequent cold lamination of plates using different compositions. Rheological parameters are adjusted to obtain stable suspensions for tape casting. The conditions for the tape casting...... and lamination will be described. Flexural strength of the reduced cermets measured using three-point bending configuration is 468±37MPa. The graded anode supports are characterized by scanning electron microscope observations, mercury porosimetry intrusion, and resistivity measurements, showing an adequate...... of tapes at room temperature without using plasticizers. This is made by the combination of two different binders with varying Tg (glass transition temperature) which resulted in plastic deformation at room temperature. Those results indicate that the proposed process is a cost-effective method...

  6. Performance Factors and Sulfur Tolerance of Metal Supported Solid Oxide Fuel Cells with Nanostructured Ni:GDC Infiltrated Anodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Sudireddy, Bhaskar Reddy; Hagen, Anke

    2015-01-01

    at a current load of 0.25Acm-2. The results were compared with literature on the sulfur tolerance of the conventional SOFC Ni/YSZ cermet anode. The comparison in terms of absolute cell resistance increase and relative anode polarization resistance increase indicate, that the nanostructured Ni:GDC MS-SOFC based...... anode is significantly more sulfur tolerant than the conventional Ni/YSZ cermet anode. © 2015 ECS - The Electrochemical Society...

  7. The thermomechanical stability of micro-solid oxide fuel cells fabricated on anodized aluminum oxide membranes

    Science.gov (United States)

    Kwon, Chang-Woo; Lee, Jae-Il; Kim, Ki-Bum; Lee, Hae-Weon; Lee, Jong-Ho; Son, Ji-Won

    2012-07-01

    The thermomechanical stability of micro-solid oxide fuel cells (micro-SOFCs) fabricated on an anodized aluminum oxide (AAO) membrane template is investigated. The full structure consists of the following layers: AAO membrane (600 nm)/Pt anode/YSZ electrolyte (900 nm)/porous Pt cathode. The utilization of a 600-nm-thick AAO membrane significantly improves the thermomechanical stability due to its well-known honeycomb-shaped nanopore structure. Moreover, the Pt anode layer deposited in between the AAO membrane and the YSZ electrolyte preserves its integrity in terms of maintaining the triple-phase boundary (TPB) and electrical conductivity during high-temperature operation. Both of these results guarantee thermomechanical stability of the micro-SOFC and extend the cell lifetime, which is one of the most critical issues in the fabrication of freestanding membrane-type micro-SOFCs.

  8. Efficiency of SOFC type fuel cells; Eficiencia de celulas combustiveis do tipo SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Alexandre Alves do; Matos, Francisco F.; Boaventura, Jaime S.; Benedicto, Joao Paulo S.; Alencar, Marcelo [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Dept. de Fisico-Quimica

    2006-07-01

    production of electric energy, mainly due to the fact that it is virtually no pollutant. Typically, the SOFC is constituted of at least seven distinct phases: fuel, anode, electrolyte substrate (separating the two electrodes), cathode, air, and electrical inter connectors (completing the electrical circuit). Thermodynamics clearly shows that electrochemical systems only can be reversible when homogeneous, what it is not case of the Sofc. Therefore, the application of equilibrium thermodynamics to these systems is incorrect. This work proposes that the Sofc can be better depicted from reactions between adsorbed species. The efficiency then is calculated as the ratio between the free energy of these reactions to the combustion heat. Thermodynamic parameter estimative is developed for the global and adsorbed species reactions. (author)

  9. Fabrication and characterization of anode-supported micro-tubular solide oxide fuel cell by phase inversion method

    Science.gov (United States)

    Ren, Cong

    Nowadays, the micro-tubular solid oxide fuel cells (MT-SOFCs), especially the anode supported MT-SOFCs have been extensively developed to be applied for SOFC stacks designation, which can be potentially used for portable power sources and vehicle power supply. To prepare MT-SOFCs with high electrochemical performance, one of the main strategies is to optimize the microstructure of the anode support. Recently, a novel phase inversion method has been applied to prepare the anode support with a unique asymmetrical microstructure, which can improve the electrochemical performance of the MT-SOFCs. Since several process parameters of the phase inversion method can influence the pore formation mechanism and final microstructure, it is essential and necessary to systematically investigate the relationship between phase inversion process parameters and final microstructure of the anode supports. The objective of this study is aiming at correlating the process parameters and microstructure and further preparing MT-SOFCs with enhanced electrochemical performance. Non-solvent, which is used to trigger the phase separation process, can significantly influence the microstructure of the anode support fabricated by phase inversion method. To investigate the mechanism of non-solvent affecting the microstructure, water and ethanol/water mixture were selected for the NiO-YSZ anode supports fabrication. The presence of ethanol in non-solvent can inhibit the growth of the finger-like pores in the tubes. With the increasing of the ethanol concentration in the non-solvent, a relatively dense layer can be observed both in the outside and inside of the tubes. The mechanism of pores growth and morphology obtained by using non-solvent with high concentration ethanol was explained based on the inter-diffusivity between solvent and non-solvent. Solvent and non-solvent pair with larger Dm value is benefit for the growth of finger-like pores. Three cells with different anode geometries was

  10. Development of solid oxide fuel cells (SOFC); Desenvolvimento de celulas a combustivel do tipo oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Souza, F.M.B. de; Carvalho, L.F.V. de; Alencar, M.G de; Boaventura, J.S. [Universidade Federal da Bahia (DFQ/UFBA), Salvador, BA (Brazil). Dept de Fisico-Quimica. Grupo de energia e Ciencias dos Materiais], e-mail: bventura@ufba.br

    2008-07-01

    The most promising technology for generating electric power, with reduced environmental impact, is the fuel cell. This technology is virtually non-polluting and the fuel supplies can be renewable. Therefore is necessary to study the technique of preparing the entire anode / electrolyte / cathode to optimize its operation. There are still major challenges to making the SOFC economically viable. The key is the improvement of manufacturing of its components and use of materials that can simultaneously reduce costs and reduce the temperature of operation. Among the properties of the cell, was shown the dependence of the efficiency of the device on the properties of the electrolyte, particularly its thickness. The mixture of YSZ with GDC in the composition of the anode and electrolyte aims to obtain a material with greater ionic conductivity. After sintering the cell was characterized by scanning electron microscopy (SEM). (author)

  11. Relaxation of stresses during reduction of anode supported SOFCs

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Chatzichristodoulou, Christodoulos; Jørgensen, Peter Stanley

    2016-01-01

    To assess the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. This work reports further details on a newly discovered creep phenomenon......, accelerated creep, taking place during the reduction of a Ni-YSZ anode. This relaxes stresses at a much higher rate (~×104) than creep during operation. Thus, the phenomenon of accelerated creep during reduction has to be considered both in the production of stacks and in the analysis of the stress field...... of reduction should decrease significantly over minutes. In this work these internal stresses are measured in-situ before and after the reduction by use of X-ray diffraction. This is done by determining the elastic micro-strains (correlating to the stresses), which are assessed from the widening of the Bragg...

  12. Anode protection system for shutdown of solid oxide fuel cell system

    Science.gov (United States)

    Li, Bob X; Grieves, Malcolm J; Kelly, Sean M

    2014-12-30

    An Anode Protection Systems for a SOFC system, having a Reductant Supply and safety subsystem, a SOFC anode protection subsystem, and a Post Combustion and slip stream control subsystem. The Reductant Supply and safety subsystem includes means for generating a reducing gas or vapor to prevent re-oxidation of the Ni in the anode layer during the course of shut down of the SOFC stack. The underlying ammonia or hydrogen based material used to generate a reducing gas or vapor to prevent the re-oxidation of the Ni can be in either a solid or liquid stored inside a portable container. The SOFC anode protection subsystem provides an internal pressure of 0.2 to 10 kPa to prevent air from entering into the SOFC system. The Post Combustion and slip stream control subsystem provides a catalyst converter configured to treat any residual reducing gas in the slip stream gas exiting from SOFC stack.

  13. Performance of Electrolyte Supported Solid Oxide Fuel Cells with STN Anodes

    DEFF Research Database (Denmark)

    Veltzé, Sune; Reddy Sudireddy, Bhaskar; Jørgensen, Peter Stanley

    2013-01-01

    In order to replace the state of the art Ni-cermet as SOFC anode, electrolyte supported cells comprising CGO/Ni infiltrated Nbdoped SrTiO3 anodes, and LSM/YSZ cathodes have been developed and tested as single 5 x 5 cm2 cells. The initial performance reached 0.4 W/cm2 at 850 C. Further tests under...

  14. Control oriented modeling of ejector in anode gas recirculation solid oxygen fuel cell systems

    International Nuclear Information System (INIS)

    Zhu Yinhai; Li Yanzhong; Cai Wenjian

    2011-01-01

    A one-equation model is proposed for fuel ejector in anode gas recirculation solid oxide fuel cell (SOFC) system. Firstly, the fundamental governing equations are established by employing the thermodynamic, fluid dynamic principles and chemical constraints inside the ejector; secondly, the one-equation model is derived by using the parameter analysis and lumped-parameter method. Finally, the computational fluid dynamics (CFD) technique is employed to obtain the source data for determining the model parameters. The effectiveness of the model is studied under a wide range of operation conditions. The effect of ejector performance on the anode gas recirculation SOFC system is also discussed. The presented model, which only contains four constant parameters, is useful in real-time control and optimization of fuel ejector in the anode gas recirculation SOFC system.

  15. Nickel/Yttria-stabilised zirconia cermet anodes for solid oxide fuel cells

    NARCIS (Netherlands)

    Primdahl, Søren

    1999-01-01

    This thesis deals with the porous Ni/yttria-stabilized zirconia (YSZ) cermet anode on a YSZ electrolyte for solid oxide fuel cells (SOFC). Such anodes are predominantly operated in moist hydrogen at 700°C to 1000°C, and the most important technological parameters are the polarization resistance and

  16. Recent Development of SOFC Metallic Interconnect

    Energy Technology Data Exchange (ETDEWEB)

    Wu JW, Liu XB

    2010-04-01

    Interest in solid oxide fuel cells (SOFC) stems from their higher e±ciencies and lower levels of emitted pollu- tants, compared to traditional power production methods. Interconnects are a critical part in SOFC stacks, which connect cells in series electrically, and also separate air or oxygen at the cathode side from fuel at the anode side. Therefore, the requirements of interconnects are the most demanding, i:e:, to maintain high elec- trical conductivity, good stability in both reducing and oxidizing atmospheres, and close coe±cient of thermal expansion (CTE) match and good compatibility with other SOFC ceramic components. The paper reviewed the interconnect materials, and coatings for metallic interconnect materials.

  17. Sulfur Poisoning of Ni/stabilized-zirconia Anodes – Effect on Long-Term Durability

    DEFF Research Database (Denmark)

    Hauch, Anne; Hagen, Anke; Hjelm, Johan

    2013-01-01

    Sulfur impurities in carbon containing fuels for solid oxide fuel cells (SOFC), e.g. natural gas and biogas, can lead to significant losses in performance due to the sulfur sensitivity of Ni/YSZ SOFC anodes. Full cells having Ni/YSZ and Ni/ScYSZ anodes have been characterized during long-term gal...... to focus on the long-term effect over a few hundred of hours. This work describes and correlates the observed evolution of anode performance, over hundreds of hours, with sulfur poisoning with the different operating conditions.......Sulfur impurities in carbon containing fuels for solid oxide fuel cells (SOFC), e.g. natural gas and biogas, can lead to significant losses in performance due to the sulfur sensitivity of Ni/YSZ SOFC anodes. Full cells having Ni/YSZ and Ni/ScYSZ anodes have been characterized during long...

  18. Characterization of a well performing and durable Ni:CGO-infiltrated anode for metal-supported SOFC

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Klemensø, Trine; Graves, Christopher R.

    3000 hours of 0.25A/cm2 galvanostatic testing at 650 ºC was shown. Furthermore, it was shown on button cells that if the cathode side consisted of a dense CGO barrier layer in combination with a LSC cathode, a performance with an area specific resistance (ASR) of 0.27 Ω cm2 at 650 ºC could be obtained....... These performance and durability characteristics are very encouraging but despite several papers on metal supported SOFC with this type of infiltrated anode [1-3], the performance and the factors controlling the performance and durability is not yet well understood. Only some initial data on symmetrical cells...

  19. Technology watch of stationary solid oxide fuel cells (SOFC) 2012; Teknikbevakning av stationaera fastoxidbraensleceller (SOFC) 2012

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Martin; Sunden, Bengt

    2013-03-15

    anode, can store a certain amount of electrochemical energy, i.e. continue to produce a certain effect even after the fuel run out. At the Huazhong University the production method of plasma spraying has been further developed. A new method of multi-phase plasma spraying has been developed in order to overcome the limitations of a non-uniform distribution of pores and particles by the conventional plasma spraying. In Nature Scientific Reports has been reported that an oxide hybrid, featuring a nanoporous Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3-{delta}} catalyst coating bonded onto the internal surface of a high-porosity La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}} (LSGM) backbone, exhibited superior catalytic activity for oxygen reduction reactions. ENE-FARM a small CHP system for individual households has great success on the Japanese market and it is expected to sell about 20,000 systems in 2012 (of which approximately 10 % SOFC), and expectations for year 2015 are 50,000 systems (of which on an estimate 25 % SOFC). Bloom Energy, in the United States, has supplied systems in the MW scale to many data centers, which require high reliability to electricity as well as a good environmental reputation. Ceramic Fuel Cells sells its products 'BlueGen' and 'Gennex' in a pre-commercial phase, mainly on the German, British and Dutch market. It should be noted that governmental support systems, such as feed-in tariffs are important to get more fuel cell systems to the market.

  20. Fabrication and characteristics of unit cell for SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gwi-Yeol; Eom, Seung-Wook; Moon, Seong-In [Korea Electrotechnology Research Institute, Kyongnam (Korea, Republic of)] [and others

    1996-12-31

    Research and development on solid oxide fuel cells in Korea have been mainly focused on unit cell and small stack. Fuel cell system is called clean generation system which not cause NOx or SOx. It is generation efficiency come to 50-60% in contrast to 40% of combustion generation system. Among the fuel cell system, solid oxide fuel cell is constructed of ceramics, so stack construction is simple, power density is very high, and there are no corrosion problems. The object of this study is to develop various composing material for SOFC generation system, and to test unit cell performance manufactured. So we try to present a guidance for developing mass power generation system. We concentrated on development of manufacturing process for cathode, anode and electrolyte.

  1. Integrating a SOFC Plant with a Steam Turbine Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Scappin, Fabio

    2009-01-01

    A Solid Oxide Fuel Cell (SOFC) is integrated with a Steam Turbine (ST) cycle. Different hybrid configurations are studied. The fuel for the plants is assumed to be natural gas (NG). Since the NG cannot be sent to the anode side of the SOFC directly, a desulfurization reactor is used to remove...

  2. Possible Future SOFC - ST Based Power Plants

    OpenAIRE

    Rokni, Masoud; Scappin, Fabio

    2009-01-01

    Hybrid systems consisting Solid Oxide Fuel Cell (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas. A desulfurization reactor removes the sulfur content in the NG while a pre-reformer break down the heavier hydrocarbons. The pre-treated fuel enters then into the anode side of the SOFC. The gases from the SOFC stacks enter into a burner to burn the rest of the fuel. The off-gases now enter into a heat recovery steam generator to produce steam for a ...

  3. Description of SOFC anode behavior by a mathematical modelling procedure

    International Nuclear Information System (INIS)

    Ielo, I.; Maggio, G.; Antonucci, V.; Giordano, N.

    1993-01-01

    One of the principal objectives in the development of SOFC is the identification of a stable Ni-cermet anode material with low polarization at high current density. In this respect, a mathematical approach, based on theoretical considerations, has been made in order to identify the optimal combination of geometrical and morphological characteristics of the system. The two limiting cases of diffusion-controlled and kinetic-controlled mechanisms are taken into account. Results in terms of limiting current have been treated by substituting into the related equations morphological parameters (surface area and pore size distribution of the support, metal content and surface area, electrode film thickness). Results are compared to existing experimental data and the influence of various parameters on the overall anode performance is evaluated. 2 tabs., 24 refs

  4. Nanoporous palladium anode for direct ethanol solid oxide fuel cells with nanoscale proton-conducting ceramic electrolyte

    Science.gov (United States)

    Li, Yong; Wong, Lai Mun; Xie, Hanlin; Wang, Shijie; Su, Pei-Chen

    2017-02-01

    In this work, we demonstrate the operation of micro-solid oxide fuel cells (μ-SOFCs) with nanoscale proton-conducting Y-BaZrO3 (BZY) electrolyte to avoid the fuel crossover problem for direct ethanol fuel cells (DEFCs). The μ-SOFCs are operated with the direct utilisation of ethanol vapour as a fuel and Pd as anode at the temperature range of 300-400 °C. The nanoporous Pd anode is achieved by DC sputtering at high Ar pressure of 80 mTorr. The Pd-anode/BYZ-electrolyte/Pt-cathode cell show peak power densities of 72.4 mW/cm2 using hydrogen and 15.3 mW/cm2 using ethanol at 400 °C. No obvious carbon deposition is seen from XPS analysis after fuel cell test with ethanol fuel.

  5. Microstructural evolution of nanograin nickel-zirconia cermet anode materials for solid oxide fuel cell applications

    International Nuclear Information System (INIS)

    Nayak, Bibhuti Bhusan

    2012-01-01

    The aim of the study is to study the structure, microstructure, porosity, thermal expansion, electrical conductivity and electrochemical behavior of the anode material thus synthesized in order to find its suitability for solid oxide fuel cell (SOFC) anode application

  6. Recent progress in the development of anode materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Cowin, Peter I.; Petit, Christophe T.G.; Lan, Rong; Tao, Shanwen [Department of Chemical and Process Engineering, University of Strathclyde, Glasgow G1 1XJ (United Kingdom); Irvine, John T.S. [School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST (United Kingdom)

    2011-05-15

    The field of research into solid oxide fuel cell (SOFC) anode materials has been rapidly moving forward. In the four years since the last in-depth review significant advancements have been made in the reduction of the operating temperature and improvement of the performance of SOFCs. This progress report examines the developments in the field and looks to draw conclusions and inspiration from this research. A brief introduction is given to the field, followed by an overview of the principal previous materials. A detailed analysis of the developments of the last 4 years is given using a selection of the available literature, concentrating on metal-fluorite cermets and perovskite-based materials. This is followed by a consideration of alternate fuels for use in SOFCs and their associated problems and a short discussion on the effect of synthesis method on anode performance. The concluding remarks compile the significant developments in the field along with a consideration of the promise of future research. The recent progress in the development of anode materials for SOFCs based on oxygen ion conducting electrolytes is reviewed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Performance Factors and Sulfur Tolerance of Metal Supported Solid Oxide Fuel Cells with Nanostructured Ni:GDC Infiltrated Anodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Sudireddy, Bhaskar Reddy; Hagen, Anke

    2016-01-01

    galvanostatic operation at a current load of 0.25 Acm−2. The results were compared with literature on the sulfur tolerance of conventional SOFC Ni/YSZ cermet anode. The comparison in terms of absolute cell resistance increase and relative anode polarization resistance increase indicates, that the nanostructured...... Ni:GDC MS-SOFC based anode is significantly more sulfur tolerant than the conventional Ni/YSZ cermet anode. Furthermore, it was shown that the believed extension of the electrochemical three-phase-boundary reaction zone in the presence of GDC must be very limited and cannot account for the higher...

  8. Effectiveness of anode in a solid oxide fuel cell with hydrogen/oxygen mixed gases

    Energy Technology Data Exchange (ETDEWEB)

    Kellogg, Isaiah D. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Koylu, Umit O. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Petrovsky, Vladimir; Dogan, Fatih [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO (United States)

    2009-06-15

    A porous Ni/YSZ cermet in mixed hydrogen and oxygen was investigated for its ability to decrease oxygen activity as the anode of a single chamber SOFC. A cell with a dense 300 {mu}m YSZ electrolyte was operated in a double chamber configuration. The Ni-YSZ anode was exposed to a mixture of hydrogen and oxygen of varying compositions while the cathode was exposed to oxygen. Double chamber tests with mixed gas on the anode revealed voltage oscillations linked to lowered power generation and increased resistance. Resistance measurements of the anode during operation revealed a Ni/NiO redox cycle causing the voltage oscillations. The results of these tests, and future tests of similar format, could be useful in the development of single chamber SOFC using hydrogen as fuel. (author)

  9. Combustion synthesis of NiO–Ce0.9Gd0.1O1.95 nanocomposite anode and its electrical characteristics of semi-cell configured SOFC assembly

    International Nuclear Information System (INIS)

    Akbari-Fakhrabadi, A.; Avila, Ricardo E.; Carrasco, Hector E.; Ananthakumar, S.; Mangalaraja, R.V.

    2012-01-01

    Highlights: ► Combustion synthesis was followed to prepare NiO–GDC nanocomposite. ► NiO–GDC anode was applied over GDC electrolyte to fabricate a semi-cell. ► Electrical conductivity of the semi-cell was characterized. ► Structure, composition, particle size and morphology of NiO–GDC were studied. - Abstract: NiO–Ce 0.9 Gd 0.1 O 1.95 (NiO–10GDC) nanocomposite anode material was synthesized through combustion technique for possible low temperature solid oxide fuel cells (LT–SOFCs). A low weight loss is seen in the TG/DTA thermogram that indicates the complete combustion of the reactant mixtures. The powder X-ray diffraction patterns showed that the presence of NiO, GDC and Ni crystallite phases in the as combusted product. Upon calcination at 600 °C, the metallic Ni oxidized to NiO. TEM images showed a wide size distribution of fine spherical GDC and large irregularly shaped NiO particles. This NiO–10GDC anode material was applied over GDC electrolyte as a porous thin layer. Using this surface engineered GDC electrolyte a semi-cell (electrode/electrolyte structure) was fabricated. The electrical conductivity of the semi-cell was characterized with respect to temperature.

  10. Fabrication and tests of anode supported solid oxide fuel cell; Fabricacao e testes de celula a combustivel de oxido solido suportada no anodo

    Energy Technology Data Exchange (ETDEWEB)

    Florio, D.Z. de [UNESP, Araraquara, SP (Brazil)], e-mail: dzflorio@ipen.br; Fonseca, F.C.; Franca, Y.V.; Muccillo, E.N.S.; Muccillo, R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Berton, M.A.C.; Garcia, C.M. [LACTEC - Instituto de Tecnologia para o Desenvolvimento, Curitiba, PR (Brazil)

    2006-07-01

    A laboratory setup was designed and put into operation for the development of solid oxide fuel cells (SOFCs). Ceramic single cells were fabricated by low-cost methods, and emphasis was given to the use of ready available raw materials. The whole project consisted of the preparation of the component materials - anode, cathode, and electrolyte - and the buildup of a hydrogen leaking-free sample chamber with platinum leads and current collectors for measuring the electrochemical properties of single SOFCs. Anode-supported single SOFCs of the type (ZrO{sub 2}:Y{sub 2}O{sub 3} + NiO) anode / (ZrO{sub 2}:Y{sub 2}O{sub 3}) electrolyte / (La{sub 0.65}Sr{sub 0.35}MnO{sub 3} + ZrO{sub 2}:Y{sub 2}O{sub 3}) cathode have been prepared and tested at 700 deg C and 800 deg C after in situ H{sub 2} anode reduction. The main results show that the slurry coating method resulted in single-cells with good reproducibility and reasonable performance, suggesting that this method can be considered for fabrication of SOFCs. (author)

  11. High conductive and long-term phase stable anode materials for SOFCs: A2FeMoO6 (A = Ca, Sr, Ba)

    Science.gov (United States)

    Huan, Yu; Li, Yining; Yin, Baoyi; Ding, Dong; Wei, Tao

    2017-08-01

    In this work, the mixed oxide-ion/electron conductor (MIEC) double-perovskite compounds A2FeMoO6 (AFMO, A = Ca, Sr, Ba) are investigated as anode materials for O2--ion conducting solid-oxide fuel cells (SOFCs). Several advantages are outlined here; 1) under H2 atmosphere, the conductivities of Ba2FeMoO6 (BFMO), Sr2FeMoO6 (SFMO) and Ca2FeMoO6 (CFMO) reach as high as 243, 302 and 561 S cm-1, respectively, which can be comparable with the commercial NiO-electrolyte anode; 2) excellent structure and phase stability at high temperature and in H2 atmosphere; 3) matched thermodynamic compatibility (such as TECs) with electrolyte materials; 4) fast oxidization for fuel with O2- ions accepted by oxygen vacancies from the electrolyte. Moreover, with H2 as fuel gas, the cell power output, cell's long-term stabilities and the structural parameter are also been examined to evaluate the AFMO anode.

  12. Thermal imaging of solid oxide fuel cell anode processes

    Energy Technology Data Exchange (ETDEWEB)

    Pomfret, Michael B.; Kidwell, David A.; Owrutsky, Jeffrey C. [Chemistry Division, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Steinhurst, Daniel A. [Nova Research Inc., Alexandria, VA 22308 (United States)

    2010-01-01

    A Si-charge-coupled device (CCD), camera-based, near-infrared imaging system is demonstrated on Ni/yttria-stabilized zirconia (YSZ) fragments and the anodes of working solid oxide fuel cells (SOFCs). NiO reduction to Ni by H{sub 2} and carbon deposition lead to the fragment cooling by 5 {+-} 2 C and 16 {+-} 1 C, respectively. When air is flowed over the fragments, the temperature rises 24 {+-} 1 C as carbon and Ni are oxidized. In an operational SOFC, the decrease in temperature with carbon deposition is only 4.0 {+-} 0.1 C as the process is moderated by the presence of oxides and water. Electrochemical oxidation of carbon deposits results in a {delta}T of +2.2 {+-} 0.2 C, demonstrating that electrochemical oxidation is less vigorous than atmospheric oxidation. While the high temperatures of SOFCs are challenging in many respects, they facilitate thermal imaging because their emission overlaps the spectral response of inexpensive Si-CCD cameras. Using Si-CCD cameras has advantages in terms of cost, resolution, and convenience compared to mid-infrared thermal cameras. High spatial ({proportional_to}0.1 mm) and temperature ({proportional_to}0.1 C) resolutions are achieved in this system. This approach provides a convenient and effective analytical technique for investigating the effects of anode chemistry in operating SOFCs. (author)

  13. Thermal imaging of solid oxide fuel cell anode processes

    Science.gov (United States)

    Pomfret, Michael B.; Steinhurst, Daniel A.; Kidwell, David A.; Owrutsky, Jeffrey C.

    A Si-charge-coupled device (CCD), camera-based, near-infrared imaging system is demonstrated on Ni/yttria-stabilized zirconia (YSZ) fragments and the anodes of working solid oxide fuel cells (SOFCs). NiO reduction to Ni by H 2 and carbon deposition lead to the fragment cooling by 5 ± 2 °C and 16 ± 1 °C, respectively. When air is flowed over the fragments, the temperature rises 24 ± 1 °C as carbon and Ni are oxidized. In an operational SOFC, the decrease in temperature with carbon deposition is only 4.0 ± 0.1 °C as the process is moderated by the presence of oxides and water. Electrochemical oxidation of carbon deposits results in a Δ T of +2.2 ± 0.2 °C, demonstrating that electrochemical oxidation is less vigorous than atmospheric oxidation. While the high temperatures of SOFCs are challenging in many respects, they facilitate thermal imaging because their emission overlaps the spectral response of inexpensive Si-CCD cameras. Using Si-CCD cameras has advantages in terms of cost, resolution, and convenience compared to mid-infrared thermal cameras. High spatial (∼0.1 mm) and temperature (∼0.1 °C) resolutions are achieved in this system. This approach provides a convenient and effective analytical technique for investigating the effects of anode chemistry in operating SOFCs.

  14. Oxidation behavior of a Ni-Fe support in SOFC anode atmosphere

    DEFF Research Database (Denmark)

    Xu, Na; Chen, Ming; Han, Minfang

    2018-01-01

    In this work, we investigated the long-term oxidation behavior of a Ni-Fe (1:1 weight ratio) support for solid oxide fuel cell (SOFC) applications. Ni-Fe supports were obtained through tape casting, high temperature sintering and pre-reducing in 97% H2/N2 (9/91)-3% H2O at 750 and 1000 °C, respect...... annealed in the two atmospheres maintained sufficiently high conductivity. The results from the current work demonstrate that the porous Ni-Fe support can be well employed in SOFCs, especially metal-supported SOFCs....

  15. Nickel-based anode with water storage capability to mitigate carbon deposition for direct ethanol solid oxide fuel cells.

    Science.gov (United States)

    Wang, Wei; Su, Chao; Ran, Ran; Zhao, Bote; Shao, Zongping; Tade, Moses O; Liu, Shaomin

    2014-06-01

    The potential to use ethanol as a fuel places solid oxide fuel cells (SOFCs) as a sustainable technology for clean energy delivery because of the renewable features of ethanol versus hydrogen. In this work, we developed a new class of anode catalyst exemplified by Ni+BaZr0.4Ce0.4Y0.2O3 (Ni+BZCY) with a water storage capability to overcome the persistent problem of carbon deposition. Ni+BZCY performed very well in catalytic efficiency, water storage capability and coking resistance tests. A stable and high power output was well maintained with a peak power density of 750 mW cm(-2) at 750 °C. The SOFC with the new robust anode performed for seven days without any sign of performance decay, whereas SOFCs with conventional anodes failed in less than 2 h because of significant carbon deposition. Our findings indicate the potential applications of these water storage cermets as catalysts in hydrocarbon reforming and as anodes for SOFCs that operate directly on hydrocarbons. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Pore-scale investigation of mass transport and electrochemistry in a solid oxide fuel cell anode

    Energy Technology Data Exchange (ETDEWEB)

    Grew, Kyle N.; Joshi, Abhijit S.; Peracchio, Aldo A.; Chiu, Wilson K.S. [Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, Storrs, CT 06269-3139 (United States)

    2010-04-15

    The development and validation of a model for the study of pore-scale transport phenomena and electrochemistry in a Solid Oxide Fuel Cell (SOFC) anode are presented in this work. This model couples mass transport processes with a detailed reaction mechanism, which is used to model the electrochemical oxidation kinetics. Detailed electrochemical oxidation reaction kinetics, which is known to occur in the vicinity of the three-phase boundary (TPB) interfaces, is discretely considered in this work. The TPB regions connect percolating regions of electronic and ionic conducting phases of the anode, nickel (Ni) and yttria-stabilized zirconia (YSZ), respectively; with porous regions supporting mass transport of the fuel and product. A two-dimensional (2D), multi-species lattice Boltzmann method (LBM) is used to describe the diffusion process in complex pore structures that are representative of the SOFC anode. This diffusion model is discretely coupled to a kinetic electrochemical oxidation mechanism using localized flux boundary conditions. The details of the oxidation kinetics are prescribed as a function of applied activation overpotential and the localized hydrogen and water mole fractions. This development effort is aimed at understanding the effects of the anode microstructure within TPB regions. This work describes the methods used so that future studies can consider the details of SOFC anode microstructure. (author)

  17. Hybrid Direct Carbon Fuel Cell Performance with Anode Current Collector Material

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Kammer Hansen, Kent

    2015-01-01

    collectors were studied: Au, Ni, Ag, and Pt. It was shown that the performance of the direct carbon fuel cell (DCFC) is dependent on the current collector materials, Ni and Pt giving the best performance, due to their catalytic activity. Gold is suggested to be the best material as an inert current collector......The influence of the current collector on the performance of a hybrid direct carbon fuel cell (HDCFC), consisting of solid oxide fuel cell (SOFC) with a molten carbonate-carbon slurry in contact with the anode, has been investigated using current-voltage curves. Four different anode current...

  18. Integrated Gasification SOFC Plant with a Steam Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Pierobon, Leonardo

    2011-01-01

    A hybrid Solid Oxide Fuel Cell (SOFC) and Steam Turbine (ST) plant is integrated with a gasification plant. Wood chips are fed to the gasification plant to produce biogas and then this gas is fed into the anode side of a SOFC cycle to produce electricity and heat. The gases from the SOFC stacks...... enter into a burner to burn the rest of the fuel. The offgases after the burner are now used to generate steam in a Heat Recovery Steam Generator (HRSG). The generated steam is expanded in a ST to produce additional power. Thus a triple hybrid plant based on a gasification plant, a SOFC plant...... and a steam plant is presented and studied. The plant is called as IGSS (Integrated Gasification SOFC Steam plant). Different systems layouts are presented and investigated. Electrical efficiencies up to 56% are achieved which is considerably higher than the conventional integrated gasification combined...

  19. Direct internal steam reforming of ethanol in a solid oxide fuel cell (SOFC) - A thermodynamic analysis

    International Nuclear Information System (INIS)

    Lima da Silva, Aline; De Fraga Malfatti, Celia; Heck, Nestor Cesar; Melo Halmenschlager, Cibele

    2003-01-01

    Among the various types of fuel cells, the solid oxide fuel cell (SOFC) has attracted considerable interest due to the possibility for operation with an internal reformer and higher system efficiency. In SOFC, high operative temperature allows the direct conversion of ethanol into H 2 and CO to take place in the electrochemical cell. Ethanol is considered to be an attractive fuel because it is a renewable energy source and presents some advantages over other green fuels such as safety in storage and handling. Direct internal reforming of ethanol, however, can produce undesirable products that diminish system efficiency and, in the case of carbon deposition over the anode, promote the growth of carbon filaments attached to the anode crystallites which generate massive forces within the electrode structure leading to its rapid breakdown. In this context, a thermodynamic analysis is fundamental to predict the product distribution as well as the conditions favorable for carbon to precipitate inside the cell. Despite of such importance, there are few works in literature dealing with thermodynamic analysis of the direct internal steam reforming of ethanol in fuel cell systems. Hence, the aim of this work is to find appropriate ranges for operating conditions where carbon deposition in SOFC with direct internal reforming operation is not feasible, in temperature range of 500- 1200K. The calculation here is more complicated than that for a reformer because the disappearance of hydrogen and the generation of H 2 O from electrochemical reaction must be taken into account. In the present study, the effects of hydrogen consumption on anode components and on carbon formation are investigated. Equilibrium determinations are performed by the Gibbs energy minimization method, considering the following species: H 2 , H 2 O, CH 4 , CO, CO 2 and C gr . (graphite). The effect of the type of solid electrolyte (oxygen-conducting and hydrogen-conducting) on carbon formation is also

  20. Progress in understanding SOFC electrodes

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Hansen, Karin Vels; Jørgensen, M.J.

    2002-01-01

    The literature of SOFC electrode kinetics and mechanisms is full of contradicting details in case of both the SOFC anode and cathode processes. Only weak patterns may be identified. One interpretation is that each of the reported data sets reflects a laboratory specific nature of each of the elec...

  1. Development of materials for use in solid oxid fuel cells anodes using renewable fuels in direct operation

    International Nuclear Information System (INIS)

    Lima, D.B.P.L. de; Florio, D.Z. de; Bezerra, M.E.O.

    2016-01-01

    Fuel cells produce electrical current from the electrochemical combustion of a gas or liquid (H2, CH4, C2H5OH, CH3OH, etc.) inserted into the anode cell. An important class of fuel cells is the SOFC (Solid Oxide Cell Fuel). It has a ceramic electrolyte that transports protons (H +) or O-2 ions and operating at high temperatures (500-1000 °C) and mixed conductive electrodes (ionic and electronic) ceramics or cermets. This work aims to develop anodes for fuel cells of solid oxide (SOFC) in order to direct operations with renewable fuels and strategic for the country (such as bioethanol and biogas). In this context, it becomes important to study in relation to the ceramic materials, especially those that must be used in high temperatures. Some types of double perovskites such as Sr2MgMoO6 (or simply SMMO) have been used as anodes in SOFC. In this study were synthesized by the polymeric precursor method, analyzed and characterized different ceramic samples of families SMMO, doped with Nb, this is: Sr2 (MgMo)1-xNbxO6 with 0 ≤ x ≤ 0.2. The materials produced were characterized by various techniques such as, thermal analysis, X-ray diffraction and scanning electron microscopy, and electrical properties determined by dc and ac measurements in a wide range of temperature, frequency and partial pressure of oxygen. The results of this work will contribute to a better understanding of advanced ceramic properties with mixed driving (electronic and ionic) and contribute to the advancement of SOFC technology operating directly with renewable fuels. (author)

  2. The impact of steam and current density on carbon formation from biomass gasification tar on Ni/YSZ, and Ni/CGO solid oxide fuel cell anodes

    Science.gov (United States)

    Mermelstein, Joshua; Millan, Marcos; Brandon, Nigel

    The combination of solid oxide fuel cells (SOFCs) and biomass gasification has the potential to become an attractive technology for the production of clean renewable energy. However the impact of tars, formed during biomass gasification, on the performance and durability of SOFC anodes has not been well established experimentally. This paper reports an experimental study on the mitigation of carbon formation arising from the exposure of the commonly used Ni/YSZ (yttria stabilized zirconia) and Ni/CGO (gadolinium-doped ceria) SOFC anodes to biomass gasification tars. Carbon formation and cell degradation was reduced through means of steam reforming of the tar over the nickel anode, and partial oxidation of benzene model tar via the transport of oxygen ions to the anode while operating the fuel cell under load. Thermodynamic calculations suggest that a threshold current density of 365 mA cm -2 was required to suppress carbon formation in dry conditions, which was consistent with the results of experiments conducted in this study. The importance of both anode microstructure and composition towards carbon deposition was seen in the comparison of Ni/YSZ and Ni/CGO anodes exposed to the biomass gasification tar. Under steam concentrations greater than the thermodynamic threshold for carbon deposition, Ni/YSZ anodes still exhibited cell degradation, as shown by increased polarization resistances, and carbon formation was seen using SEM imaging. Ni/CGO anodes were found to be more resilient to carbon formation than Ni/YSZ anodes, and displayed increased performance after each subsequent exposure to tar, likely due to continued reforming of condensed tar on the anode.

  3. Effect of inlet fuel type on the degradation of Ni/YSZ anode of solid oxide fuel cell by carbon deposition

    Directory of Open Access Journals (Sweden)

    Suttichai Assabumrungrat

    2006-11-01

    Full Text Available According to the high operating temperature of Solid Oxide Fuel Cell (SOFC (700-1100ºC, it is known that some hydrocarbon fuels can be directly used as inlet fuel instead of hydrogen by feeding straight to the anode. This operation is called a direct internal reforming SOFC (DIR-SOFC. However, the major difficulty of this operation is the possible degradation of anode by the carbon deposition, as the carbon species are easily formed. In the present work, the effect of inlet fuel (i.e. H2, synthesis gas (H2+CO, CH4, CH4+H2O, CH3OH+H2O, and C2H5OH+H2O on the degradation of nickel cermet (Ni/YSZ, which is the most common anode material of SOFC, was studied.It was found from the work that hydrogen and synthesis gas (CO+H2 are proper to be used as direct inlet fuels for DIR-SOFC with Ni/YSZ anode, since the carbon formation on Ni/YSZ occurred in the small quantity. The mixture of methane and steam (CH4+H2O can also be used as the inlet feed, but the H2O/CH4 ratio plays an important role. In contrast, pure methane (CH4, methanol with steam (CH3OH+H2O and ethanol with steam (C2H5OH+H2O are not suitable for using as direct inlet fuel for DIR-SOFC with Ni/YSZ anode even the higher H2O/CH3OH and H2O/C2H5OH ratios were applied.

  4. Methane Steam Reforming over an Ni-YSZ Solid Oxide Fuel Cell Anode in Stack Configuration

    DEFF Research Database (Denmark)

    Mogensen, David; Grunwaldt, Jan-Dierk; Hendriksen, Peter Vang

    2014-01-01

    The kinetics of catalytic steam reforming of methane over an Ni-YSZ anode of a solid oxide fuel cell (SOFC) have been investigated with the cell placed in a stack configuration. In order to decrease the degree of conversion, a single cell stack with reduced area was used. Measurements were...

  5. The surface evolution of La0.4Sr0.6TiO3+δ anode in solid oxide fuel cells: Understanding the sulfur-promotion effect

    Science.gov (United States)

    Yan, Ning; Zanna, Sandrine; Klein, Lorena H.; Roushanafshar, Milad; Amirkhiz, Babak S.; Zeng, Yimin; Rothenberg, Gadi; Marcus, Philippe; Luo, Jing-Li

    2017-03-01

    The ideal solid oxide fuel cells (SOFCs) can be powered by readily available hydrocarbon fuels containing impurities. While this is commonly recognized as a key advantage of SOFC, it also, together with the elevated operating temperature, becomes the main barrier impeding the in-situ or operando investigations of the anode surface chemistry. Here, using a well-designed quenching experiment, we managed to characterize the near-surface structure of La0.4Sr0.6TiO3+δ (LST) anode in SOFCs fuelled by H2S-containing methane. This new method enabled us to clearly observe the surface amorphization and sulfidation of LST under simulated SOFC operating conditions. The ∼1 nm-thick two dimensional sulfur-adsorbed layer was on top of the disordered LST, containing -S, -SH and elemental sulfur species. In SOFC test, such "poisoned" anode showed increased performances: a ten-fold enhanced power density enhancement (up to 30 mW cm-2) and an improved open circuit voltage (from 0.69 V to 1.17 V). Moreover, its anodic polarization resistance in methane decreased to 21.53 Ω cm2, a difference of 95% compared with the sulfur-free anode. Control experiments confirmed that once the adsorbed sulfur species were removed electrochemically, methane conversion slowed down simultaneously till full stop.

  6. Accelerated creep in solid oxide fuel cell anode supports during reduction

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Makowska, Malgorzata Grazyna; Greco, Fabio

    2016-01-01

    To evaluate the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. The creep of reduced Ni-YSZ anode support at operating conditions has been...... studied previously. In this work a newly discovered creep phenomenon taking place during the reduction is reported. This relaxes stresses at a much higher rate (∼ x104) than creep during operation. The phenomenon was studied both in three-point bending and uniaxial tension. Differences between the two...... the NiO and the YSZ phases occurs during reduction. The accelerated creep should practically eliminate any residual stress in the anode support in an SOFC stack, as has previously been indirectly observed. This phenomenon has to be taken into account both in the production of stacks and in the simulation...

  7. SOFC regulation at constant temperature: Experimental test and data regression study

    International Nuclear Information System (INIS)

    Barelli, L.; Bidini, G.; Cinti, G.; Ottaviano, A.

    2016-01-01

    Highlights: • SOFC operating temperature impacts strongly on its performance and lifetime. • Experimental tests were carried out varying electric load and feeding mixture gas. • Three different anodic inlet gases were tested maintaining constant temperature. • Cathodic air flow rate was used to maintain constant its operating temperature. • Regression law was defined from experimental data to regulate the air flow rate. - Abstract: The operating temperature of solid oxide fuel cell stack (SOFC) is an important parameter to be controlled, which impacts the SOFC performance and its lifetime. Rapid temperature change implies a significant temperature differences between the surface and the mean body leading to a state of thermal shock. Thermal shock and thermal cycling introduce stress in a material due to temperature differences between the surface and the interior, or between different regions of the cell. In this context, in order to determine a control law that permit to maintain constant the fuel cell temperature varying the electrical load and the infeed fuel mixture, an experimental activity were carried out on a planar SOFC short stack to analyse stack temperature. Specifically, three different anodic inlet gas compositions were tested: pure hydrogen, reformed natural gas with steam to carbon ratio equal to 2 and 2.5. By processing the obtained results, a regression law was defined to regulate the air flow rate to be provided to the fuel cell to maintain constant its operating temperature varying its operating conditions.

  8. Municipal Solid Waste Gasification Plant Integrated With SOFC and Gas Turbine

    DEFF Research Database (Denmark)

    Bellomare, Filippo; Rokni, Masoud

    2012-01-01

    An interesting source of producing energy with low pollutants emission and reduced environmental impact are the biomasses; particularly using Municipal Solid Waste (MSW) as fuel, can be a competitive solution not only to produce energy with negligible costs but also to decrease the storage...... in landfills. A Municipal Solid Waste Gasification Plant Integrated with Solid Oxide Fuel Cell (SOFC) and Gas Turbine (GT) has been studied and the plant is called IGSG (Integrated Gasification SOFC and GT). Gasification plant is fed by MSW to produce syngas by which the anode side of a SOFC is fed wherein...

  9. High temperature sealing method : induction brazing for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Y.H.; Lee, S.B.; Song, R.H.; Shin, D.R. [Korea Inst. of Energy Research, Daejeon (Korea, Republic of); Lim, T.H. [Korea Inst. of Energy Research, Daejeon (Korea, Republic of). Advanced Fuel Cell Research Center

    2009-07-01

    This study examined the use of induction brazing as a high temperature sealing method for solid oxide fuel cells (SOFCs). Nickel-based brazing alloys were modified using reactive titanium-hydride (TiH2). The gas sealing properties of the induction brazing process on anode-supported tubular SOFCs and ferritic stainless steel were evaluated. Brazing alloys BNi-2 and BNi-4 were not wetted in a yttria-silica-zircon (YSZ) electrolyte. The brazing alloy with added TiH2 showed good wettability with the YSZ electrolyte as a result of the formation of a TiOX layer. Only the BNi-4 alloy joined with the YSZ electrolyte. An open circuit voltage (OCV) value was used to estimate the gas tightness of the brazed cell. It was concluded that the BNi-4 TiH2 modified alloy is a suitable sealing material for SOFCs operating in temperatures up to 750 degrees C.

  10. Direct modeling of the electrochemistry in the three-phase boundary of solid oxide fuel cell anodes by density functional theory: a critical overview.

    Science.gov (United States)

    Shishkin, M; Ziegler, T

    2014-02-07

    The first principles modeling of electrochemical reactions has proven useful for the development of efficient, durable and low cost solid oxide full cells (SOFCs). In this account we focus on recent advances in modeling of structural, electronic and catalytic properties of the SOFC anodes based on density functional theory (DFT) first principle calculations. As a starting point, we highlight that the adequate analysis of cell electrochemistry generally requires modeling of chemical reactions at the metal/oxide interface rather than on individual metal or oxide surfaces. The atomic models of Ni/YSZ and Ni/CeO2 interfaces, required for DFT simulations of reactions on SOFC anodes are discussed next, together with the analysis of the electronic structure of these interfaces. Then we proceed to DFT-based findings on charge transfer mechanisms during redox reactions on these two anodes. We provide a comparison of the electronic properties of Ni/YSZ and Ni/CeO2 interfaces and present an interpretation of their different chemical performances. Subsequently we discuss the computed energy pathways of fuel oxidation mechanisms, obtained by various groups to date. We also discuss the results of DFT studies combined with microkinetic modeling as well as the results of kinetic Monte Carlo simulations. In conclusion we summarize the key findings of DFT modeling of metal/oxide interfaces to date and highlight possible directions in the future modeling of SOFC anodes.

  11. SOFC anode. Hydrogen oxidation at porous nickel and nickel/zirconia electrodes

    NARCIS (Netherlands)

    de Boer, B.

    1998-01-01

    In the ongoing search for alternative and environmental friendly power generation facilities, the fuel cell is a good candidate. There are several types of fuel cells with large differences in application, size, cost and operating range. The Solid Oxide Fuel Cell (SOFC) is a high temperature fuel

  12. Planar metal-supported SOFC with novel cermet anode

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Hjelm, Johan; Klemensø, Trine

    2011-01-01

    Metal-supported solid oxide fuel cells are expected to offer several potential advantages over conventional anode (Ni-YSZ) supported cells. For example, increased resistance against mechanical and thermal stresses and a reduction in material costs. When Ni-YSZ based anodes are used in metal suppo...

  13. Dynamic model with experimental validation of a biogas-fed SOFC plant

    International Nuclear Information System (INIS)

    D'Andrea, G.; Gandiglio, M.; Lanzini, A.; Santarelli, M.

    2017-01-01

    Highlights: • 60% of DIR into the SOFC anode reduces the air blower parasitic losses by 14%. • PID-controlled cathode airflow enables fast thermal regulation of the SOFC. • Stack overheating occurs due to unexpected reductions in the cathode airflow. • Current ramp rates higher than +0.30 A/min lead to an excessive stack overheating. - Abstract: The dynamic model of a poly-generation system based on a biogas-fed solid oxide fuel cell (SOFC) plant is presented in this paper. The poly-generation plant was developed in the framework of the FP7 EU-funded project SOFCOM ( (www.sofcom.eu)), which consists of a fuel-cell based polygeneration plant with CO_2 capture and re-use. CO_2 is recovered from the anode exhaust of the SOFC (after oxy-combustion, cooling and water condensation) and the Carbon is fixed in the form of micro-algae in a tubular photobioreactor. This work focuses on the dynamic operation of the SOFC module running on steam-reformed biogas. Both steady state and dynamic operation of the fuel cell stack and the related Balance-of-Plant (BoP) has been modeled in order to simulate the thermal behavior and performance of the system. The model was validated against experimental data gathered during the operation of the SOFCOM proof-of-concept showing good agreement with the experimental data. The validated model has been used to investigate further on the harsh off-design operation of the proof-of-concept. Simulation results provide guidelines for an improved design of the control system of the plant, highlighting the feasible operating region under safe conditions and means to maximize the overall system efficiency.

  14. A novel high performance composite anode with in situ growth of Fe-Ni alloy nanoparticles for intermediate solid oxide fuel cells

    International Nuclear Information System (INIS)

    Li, Jingcheng; Yu, Yan; Yin, Yi-Mei; Zhou, Ning; Ma, Zi-Feng

    2017-01-01

    Highlights: • A composite anode with endogenous Fe-Ni alloy nanoparticles has been prepared. • The redox reversibility of the anode has been confirmed by XRD. • The E_a of H_2 oxidation at the anode is much smaller than that at Ni-YSZ anode. • A ScSZ supported cell achieves MPD of 0.71 Wcm"−"2 and R_p of 0.16 Ω cm"2 at 800 °C. • The single cell shows stable output during 105 h testing at 800 °C 0.7 V in wet H_2". - Abstract: A redox reversible composite anode with Fe-Ni alloy nanoparticles in situ growth on SrLaFeO_4-type and LaFeO_3-type oxide substrates has been prepared for intermediate temperature solid oxide fuel cell (IT-SOFC) by reducing perovskite precursor La_0_._4Sr_0_._6Fe_0_._7_5Ni_0_._1Nb_0_._1_5O_3_-_δ (LSFNNb) in wet H_2 at 900 °C for 1 h. The anode has shown an excellent electrochemical catalytic activity for oxidation of hydrogen with much smaller E_a (25.1 ∼ 68.9 kJ mol"−"1) than the value (>160 kJ mol"−"1) at Ni-YSZ anode. A scandium stabilized zirconia (ScSZ) electrolyte supported SOFC with the anode achieves maximum power densities of 0.71, 0.52, 0.35, and 0.21 W cm"−"2 at 800, 750, 700 and 650 °C, respectively in wet H_2 (3% H_2O), and the corresponding R_p of 0.16, 0.21, 0.35, and 0.60 Ω cm"2 under OCV. Moreover, the single cell shows stable power output during ∼105 h operation at 800 °C under 0.7 V in wet H_2 after a initial degradation, indicating that R-LSFNNb is an excellent candidate as anode of IT-SOFC.

  15. Mesoporous zirconia-ceria for anodes of SOFC and catalyzer

    Energy Technology Data Exchange (ETDEWEB)

    Fantini, Marcia Carvalho de Abreu; Cassimiro, Vinicius Roberto de Sylos; Monteiro, Rafael Cartoni, E-mail: mfantini@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica

    2016-07-01

    Full text: The ceria (CeO{sub 2}) and zirconia (ZrO{sub 2}) based materials are present in several technological applications, mainly as Solid Oxide Fuel Cells (SOFC) anodes and catalysts, for hydrogen production and automotive converter (Three-Way Catalysis). The solid solution Zr{sub x}Ce{sub 1-x}O{sub 2-δ} has attracted special attention, since it shows better thermal stability and higher oxygen storage capacity (OSC), if compared to the non-doped oxides. The mesoporous materials (pores of 2 to 50 nm) show high surface area and gas permeability, important properties for SOFCs and catalysts efficiency. In this work, mesoporous ceria-zirconia (Zr{sub 0.1}Ce{sub 0.9}O{sub 2-δ}) was synthesized by a sol-gel route using inorganic chlorides (ZrCl{sub 4} e CeCl{sub 3.7}H{sub 2}O) as precursors, block copolymer P123 (PEO{sub 20}PPO{sub 70}PEO{sub 20}) as template and TIPB (triisopropyl- benzene) as swelling agent. The solution was submitted to hydrothermal treatment for 48h at 80°C and calcined at 400°C to remove the template, resulting in the crystallized oxide. The characterization was performed by X-ray diffraction at high angles (XRD), small angle X-ray scattering (SAXS), nitrogen adsorption isotherms (NAI) and transmission and scanning electron microscopy (TEM and SEM). The results showed that the material has high surface area (≈ 110 m{sup 2}g{sup -1}), a wide pore size distribution with mean values around 30 nm, predominant cubic phase Fm3m and, in less quantity, tetragonal P4{sub 2}/nmc. The micrographs revealed that the oxide is totally nano-crystallized, having pores with slit shape and a secondary smaller mesoporosity with a narrow size distribution. The amount of P123 in the synthesis was also varied in order to produce pores with different shapes. Four samples were produced with different TIPB/P123 mass rate (0, 1, 2, 4), therefore was possible to verify the pore size expansion due to the swelling addition. The structural and morphological properties

  16. Ni/Ni-YSZ current collector/anode dual layer hollow fibers for micro-tubular solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kanawka, K.; Othman, M.H.D.; Droushiotis, N.; Wu, Z.; Kelsall, G.; Li, K. [Department of Chemical Engineering and Chemical Technology, Imperial College London, London SW7 2AZ (United Kingdom)

    2011-10-15

    A co-extrusion technique was employed to fabricate a novel dual layer NiO/NiO-YSZ hollow fiber (HF) precursor which was then co-sintered at 1,400 C and reduced at 700 C to form, respectively, a meshed porous inner Ni current collector and outer Ni-YSZ anode layers for SOFC applications. The inner thin and highly porous ''mesh-like'' pure Ni layer of approximately 50 {mu}m in thickness functions as a current collector in micro-tubular solid oxide fuel cell (SOFC), aiming at highly efficient current collection with low fuel diffusion resistance, while the thicker outer Ni-YSZ layer of 260 {mu}m acts as an anode, providing also major mechanical strength to the dual-layer HF. Achieved morphology consisted of short finger-like voids originating from the inner lumen of the HF, and a sponge-like structure filling most of the Ni-YSZ anode layer, which is considered to be suitable macrostructure for anode SOFC system. The electrical conductivity of the meshed porous inner Ni layer is measured to be 77.5 x 10{sup 5} S m{sup -1}. This result is significantly higher than previous reported results on single layer Ni-YSZ HFs, which performs not only as a catalyst for the oxidation reaction, but also as a current collector. These results highlight the advantages of this novel dual-layer HF design as a new and highly efficient way of collecting current from the lumen of micro-tubular SOFC. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Hydrogen consumption and power density in a co-flow planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Ben Moussa, Hocine; Zitouni, Bariza [Laboratoire d' etude des systemes energetiques industriels (LESEI), Universite de Batna, Batna (Algeria); Oulmi, Kafia [Laboratoire de chimie et de chimie de l' environnement, Universite de Batna, Batna (Algeria); Mahmah, Bouziane; Belhamel, Maiouf [CDER, BP. 62 Route de l' Observatoire. Bouzareah. Alger (Algeria); Mandin, Philippe [Centre de Developpement des Energies Renouvelables (CDER), LECA, UMR 7575 CNRS-ENSCP Paris 6 (France)

    2009-06-15

    In the present work, power density and hydrogen consumption in a co-flow planar solid oxide fuel cell (SOFC) are studied according to the inlet functional parameters; such as the operational temperature, the operational pressure, the flow rates and the mass fractions of the species. Furthermore, the effect of the cell size is investigated. The results of a zero and a one-dimensional numerical electro-dynamic model predict the remaining quantity of the fed hydrogen at the output of the anode flow channel. The remaining hydrogen quantities and the SOFC's power density obtained are discussed as a function of the inlet functional parameters, the geometrical configuration of the cell and several operating cell voltages values. (author)

  18. Development and manufacturing of tape casted, anode-supported solid oxide fuel cells; Entwicklung und Herstellung von foliengegossenen, anodengestuetzten Festoxidbrennstoffzellen

    Energy Technology Data Exchange (ETDEWEB)

    Schafbauer, Wolfgang

    2010-07-01

    Solid oxide fuel cells offer high potential in transforming the chemical energy of hydrogen or natural gas into electrical energy. Due to the high efficiency of fuel cells, lots of effort has been made in the improvement of net efficiency and in materials development during the last years. Recently, the introduction of high performance, low-cost production technologies become more and more important. At the Institute of Energy Research IEF-1 of Forschungszentrum Julich, standard SOFCs were processed by time and work consuming methods. On the way to market entrance, product costs have to be reduced drastically. The aim of this thesis is the introduction of a high efficient low-cost processing route for the SOFC manufacturing. Therefore, the well-known and well established shaping technology tape casting was used for generating the anode substrates. As the first goal of this approach, two different tape casting slurries were developed in order to get substrates in the thickness range from 300 to 500 {mu}m after sintering. After shaping of the substrates, sinter regimes for the different necessary coatings were adapted to the novel substrate types in order to obtain cells with high performance and strength. Therefore, the different coating technologies like screen printing and vacuum slip casting were used for cell manufacturing. The optimization of the different coating steps during cell manufacturing led to high performance SOFCs with a 10% higher power output compared to the Julich state-of-the-art SOFC. Additional experiments verified the workability of the novel tape cast substrates for the manufacturing of near-net-shape SOFC. Finally, the novel cell types based on tape cast substrates were assembled to stacks with up to ten repeating units. Stack tests showed identical performance and degradation compared to stacks containing state-of-the-art SOFCs. Thus, the complete lifetime circle of a SOFC starting from powder preparation to stack assembly has been

  19. Numerical investigation of a novel burner to combust anode exhaust gases of SOFC stacks

    Directory of Open Access Journals (Sweden)

    Pianko-Oprych Paulina

    2017-09-01

    Full Text Available The aim of the present study was a numerical investigation of the efficiency of the combustion process of a novel concept burner under different operating conditions. The design of the burner was a part of the development process of a complete SOFC based system and a challenging combination of technical requirements to be fulfilled. A Computational Fluid Dynamics model of a non-premixed burner was used to simulate combustion of exhaust gases from the anode region of Solid Oxide Fuel Cell stacks. The species concentrations of the exhaust gases were compared with experimental data and a satisfactory agreement of the conversion of hydrocarbons was obtained. This validates the numerical methodology and also proves applicability of the developed approach that quantitatively characterized the interaction between the exhaust gases and burner geometry for proper combustion modelling. Thus, the proposed CFD approach can be safely used for further numerical optimisation of the burner design.

  20. Identification of a Methane Oxidation Intermediate on Solid Oxide Fuel Cell Anode Surfaces with Fourier Transform Infrared Emission.

    Science.gov (United States)

    Pomfret, Michael B; Steinhurst, Daniel A; Owrutsky, Jeffrey C

    2013-04-18

    Fuel interactions on solid oxide fuel cell (SOFC) anodes are studied with in situ Fourier transform infrared emission spectroscopy (FTIRES). SOFCs are operated at 800 °C with CH4 as a representative hydrocarbon fuel. IR signatures of gas-phase oxidation products, CO2(g) and CO(g), are observed while cells are under load. A broad feature at 2295 cm(-1) is assigned to CO2 adsorbed on Ni as a CH4 oxidation intermediate during cell operation and while carbon deposits are electrochemically oxidized after CH4 operation. Electrochemical control provides confirmation of the assignment of adsorbed CO2. FTIRES has been demonstrated as a viable technique for the identification of fuel oxidation intermediates and products in working SOFCs, allowing for the elucidation of the mechanisms of fuel chemistry.

  1. Electrochemical performance and stability of Ni1-xCox-based cermet anode for direct methane-fuelled solid oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Nicharee Wongsawatgul

    2017-01-01

    Full Text Available Carbon deposition on Ni-based anode is well-known as a major barrier for the practical use and commercialization of hydrocarbon-fuelled solid oxide fuel cells (SOFCs. In this work, Co alloying in Ni-YSZ was studied as an alternative anode material for using CH4 as a fuel. The Ni-YSZ and Ni-Co alloyed-YSZ were prepared by the traditional impregnation method without further mixing processes. After sintering and reduction in H2 atmosphere, the introduced Co can completely dissolved into the Ni lattice and changed the morphology with an increase in the Ni-YSZ grain size and showed a better uniform microstructure. The Co alloying also enhanced the electrochemical performance under CH4 fuel by reducing the resistance and anodic overvoltage. Moreover, the Co addition enhanced the stability of the cell with CH4 a constant load current of 80 mA for 60 h. This performance related to the carbon deposition on the anode surface. The Co alloying showed a high efficiency to suppress the carbon deposition and improved the electrochemical performance of an SOFC cell operating under CH4 fuel.

  2. Ceramic materials for SOFCs: Current status

    Directory of Open Access Journals (Sweden)

    Kozhukharov, V.

    2002-10-01

    Full Text Available It is well known that the main parts of Solid Oxide Fuel Cells (SOFCs are build from ceramic materials. Namely the ceramic materials and composites, used for SOFCs manufacturing, are objects of the overview in the present work. The analysis carried out covers the last current publications in the field discussed. Special attention and examination in details have been done on patents state-of-the-art. After a background and short classification of the ceramic SOFCs materials the attention is focused on cathode, electrolyte, anode, interconnection and sealing materials. Their requirements, structure, thermal stability, composition control and behavior, processing and performance are the object of overview. A correlation has been made between the phase diagrams oxygen incorporation and transport, and SOFC advantages, generally for materials of lanthanum- base perovskite family. In order to analyze the innovative investigations regarding the patent branch of the SOFCs development and application, an object of review was patents from Japan, USA, Germany and European Union. Some examples of the inventions with accent on the ceramic materials are shown. In addition the tendency regarding R & D activities of SOFCs development materials from the leading companies in the world is analyzed. On the base of the most important technological and economical parameters of cell cathode/electrolyte/anode materials an attempt for evaluation and correlation has been made and innovative conceptions are shown.

    Es bien sabido que los componentes principales de las celdas de combustible de óxido sólido (SOFCs estan constituidos por materiales cerámicos. Dichos materiales cerámicos y materiales compuestos que se utilizan en la fabricación de SOFCs son objeto de estudio en el presente trabajo. El análisis llevado a cabo incluye la revisión de las últimas publicaciones en la materia, con una especial atención y examen minucioso sobre las patentes m

  3. Manufacturing of Electrolyte and Cathode Layers SOFC Using Atmospheric Spraying Method and Its Characterization

    Directory of Open Access Journals (Sweden)

    S. Sulistyo

    2012-12-01

    Full Text Available The use of Solid Oxide Fuel Cell (SOFC has created various interest in many parties, due to its capability to convert gases into electricity. The main requirement of SOFC cell components is to be produced as thin as possible to minimize the losses of electrical resistance, as well as able to support internal and external loads. This paper discusses the procedure of making a thin electrolyte layer, as well as a porous thin layer cathode using atmospheric spraying technique. The procedure of spraying was in room temperature with the process of sintering at temperature of 13500 C held for 3 hours. The SOFC characterization of electrolyte and cathode microstructure was determined by using the SEM, FESEM, XRD and impedance spectroscopy, to measure the impedance of SOFC cells. The results show that the thickness of thin layer electrolyte and porous cathode obtained of about 20 µm and 4 µm, respectively. Also the SOFC cell impedance was measured of 2.3726 x 106 Ω at room temperature. The finding also demonstrated that although the materials (anode, cathode and electrolyte possess different coefficient thermal expansion, there was no evidence of flaking layers which seen the materials remain intact. Thus, the atmospheric spraying method can offer an alternative method to manufacturing of SOFC thin layer electrolyte and cathode. [Key words: SOFC; spraying method; electrolyte; cathode

  4. Preparation of anode-electrolyte structures using graphite, sodium bicarbonate or citric acid as pore forming agents for application in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Paz Fiuza, Raigenis da; Silva, Marcos Aurelio da; Guedes, Bruna C.; Pontes, Luiz A.; Boaventura, Jaime Soares [UFBA, Salvador, Bahia (Brazil). Energy and Materials Science Group

    2010-07-01

    Cermets based on Ni supported on YSZ or GDC were prepared for use as anode in direct reform SOFCs. NaHCO3 (Na-Ni-YSZ and Na-Ni-GDC) or citric acid (Ac-Ni-YSZ and Ac-Ni-GDC) were used as pore forming agents (PFAs). The SOFC anode was also prepared using graphite (G-Ni-YSZ and G-Ni-GDC) as PFA for the purposes of comparison. The testing unitary SOFC, planar type, was made by pressing the anode-electrolyte assembly, followed by sintering at 1500 C. After this, LSM (lanthanum and strontium manganite) paint was used for the cathode deposition. The powdered cermets were evaluated in ethanol steam reforming at 650 C. The ethanol conversion was 84% and 32% for cermets Na-Ni-YSZ and G-Ni-YSZ, respectively and the selectivity to H{sub 2} was 32 and 20% for the two cermets, respectively. The Na-Ni-YSZ cermet was ten times more resistant to carbon deposition than the G-Ni-YSZ cermet. SEM micrographs of the anode-electrolyte assembly showed that the use of NaHCO{sub 3} as PFA created a well formed interface between layers with homogeneously distributed pores. In contrast, graphite as PFA formed a loose interface between anode and electrolyte. The performance of the unitary SOFC was evaluated using ethanol, hydrogen or methane as fuel. The cell operated well using any of these fuels; however, they exhibited different electrochemical behavior. (orig.)

  5. Synthesis of modified calcium aluminate with lanthanum manganite (LSM) for possible use in solid oxide fuel cell (SOFC)

    International Nuclear Information System (INIS)

    Veiga, F.C.T.; Jurado, J.; Sousa, V.C. de

    2016-01-01

    The fuel cells solid oxide (SOFC) is made up of three basic elements: two electrodes, the anode and cathode and a conductive electrolyte ions. The objective of this work consists of calcium aluminate synthesis modified LSM in a 1: 1 by combustion synthesis method with a view to its use as a cathode in SOFC. The characterization of the post was carried out by the methods of XRD, TEM and EIS. After heat treatment at 1200°C/4 hours it was possible to obtain Ca0.5Sr1.5MnO4 and CaMnO2.56 phases. The material showed a semiconductor characteristics because with increasing temperature the electrical resistance value tends to decrease obtaining electrical conductivity greater than 10-6S / cm featuring an extrinsic semiconductor with an activation energy of 0.12. Therefore, with an activation energy value within the range of materials used for a SOFC cathodes. (author)

  6. High-velocity DC-VPS for diffusion and protecting barrier layers in solid oxide fuel cells (SOFCs)

    Science.gov (United States)

    Henne, R. H.; Franco, T.; Ruckdäschel, R.

    2006-12-01

    High-temperature fuel cells of the solid oxide fuel cell (SOFC) type as direct converter of chemical into electrical energy show a high potential for reducing considerably the specific energy consumption in different application fields. Of particular interest are advanced lightweight planar cells for electricity supply units in cars and other mobile systems. Such cells, in one new design, consist mainly of metallic parts, for example, of ferrite steels. These cells shall operate in the temperature range of 700 to 800 °C where oxidation and diffusion processes can be of detrimental effect on cell performance for long-term operation. Problems arise in particular by diffusion of chromium species from the interconnect or the cell containment into the electrolyte/cathode interface forming insulating phases and by the mutual diffusion of substrate and anode material, for example, iron and chromium from the ferrite into the anode and nickel from the anode into the ferrite, which in both cases reduces performance and system lifetime. Additional intermediate layers of perovskite-type material, (e.g., doped LaCrO3) applied with high-velocity direct-current vacuum plasma spraying (DC-VPS) can reduce such effects considerably if they are stable and of high electronic conductivity.

  7. Numerical model for evaluation of the effects of carbon deposition on the performance of 1 kW SOFC stack – a proposal

    Directory of Open Access Journals (Sweden)

    Motylinski Konrad

    2017-01-01

    Full Text Available Solid oxide fuel cells are high-temperature electrochemical energy conversion devices which operate at elevated temperature (600- 900°C. As a result it possible to internally reform the incoming fuel, thus except hydrogen and carbon monoxide, SOFCs can be fuelled with various hydrocarbonaceous gases. The presence of carbon-containing compounds in the fuel might result in the formation and of carbon in a form of a thin layer on the SOFC anode. The carbon deposition process depends on the thermodynamic conditions, such as temperature and steam to carbon ratio. The higher the temperature, the longer period of time is required for the solid carbon particles to deposit on the porous surface. The correlation used for this study is based on creating the ternary diagrams or Gibb’s diagrams. The presented results cover a first stage of the analysis of the carbon deposition processes in SOFCs, focusing mainly on the numerical study of the changes of the fuel cell performance due to degradation of anode performance. A dedicated model of SOFC was proposed. It accounts for the diminution of the active area and/or deactivation by the increase of the resistance of the anode. The article presents the proposed methodology and the numerical approach.

  8. Online gas composition estimation in solid oxide fuel cell systems with anode off-gas recycle configuration

    Science.gov (United States)

    Dolenc, B.; Vrečko, D.; Juričić, Ð.; Pohjoranta, A.; Pianese, C.

    2017-03-01

    Degradation and poisoning of solid oxide fuel cell (SOFC) stacks are continuously shortening the lifespan of SOFC systems. Poisoning mechanisms, such as carbon deposition, form a coating layer, hence rapidly decreasing the efficiency of the fuel cells. Gas composition of inlet gases is known to have great impact on the rate of coke formation. Therefore, monitoring of these variables can be of great benefit for overall management of SOFCs. Although measuring the gas composition of the gas stream is feasible, it is too costly for commercial applications. This paper proposes three distinct approaches for the design of gas composition estimators of an SOFC system in anode off-gas recycle configuration which are (i.) accurate, and (ii.) easy to implement on a programmable logic controller. Firstly, a classical approach is briefly revisited and problems related to implementation complexity are discussed. Secondly, the model is simplified and adapted for easy implementation. Further, an alternative data-driven approach for gas composition estimation is developed. Finally, a hybrid estimator employing experimental data and 1st-principles is proposed. Despite the structural simplicity of the estimators, the experimental validation shows a high precision for all of the approaches. Experimental validation is performed on a 10 kW SOFC system.

  9. Development of Planar Metal Supported SOFC with Novel Cermet Anode

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Hjelm, Johan; Klemensø, Trine

    2009-01-01

    Metal-supported solid oxide fuel cells are expected to offer several potential advantages over conventional anode (Ni-YSZ) supported cells, such as increased resistance against mechanical and thermal stresses and a reduction in materials cost. When Ni-YSZ based anodes are used in metal supported ...

  10. SOFC direct fuelling with high-methane gases: Optimal strategies for fuel dilution and upgrade to avoid quick degradation

    International Nuclear Information System (INIS)

    Baldinelli, A.; Barelli, L.; Bidini, G.; Di Michele, A.; Vivani, R.

    2016-01-01

    Highlights: • SOFCs are operated on natural gas and biogas direct feeding. • Methane partial oxidation and dry reforming are compared. • The optimal oxygen-to-carbon stoichiometry to avoid degradation is determined for both natural gas and biogas. • NiYSZ anodes degradation mechanisms are investigated though SEM-EDX and XRD. - Abstract: In the outlook of the transition to the carbon-free society, low-carbon gases, such as natural gas or biogas, are very promising. The first is commonly used for stationary applications based on Solid Oxide Fuel Cells (SOFCs) equipped with external reformers. Similar installations are required when the SOFC is run on biogas. Yet, high SOFC operative temperature enables internal decomposition of light hydrocarbons, therefore allowing the suppression of external reforming. Evidently, this brings about benefits in terms of system complexity and cost reduction. Nonetheless, unlike reformate fuels, direct exposure to large amount of methane favours SOFC anodes degradation. Implementing a systematic experimental approach, this paper aims at determining a simple operative strategy to carry out direct feeding without meeting with quick degradation issues, producing interesting outcomes with regards to the management of SOFC-based systems. Particularly, the regulation of the oxygen-to-carbon (O/C) relative fraction of the fuel through air addition to natural gas and partial CO_2 separation from biogas is helpful in the prevention of those mechanisms. In this study, NiYSZ anode SOFCs are exposed to air-diluted natural gas and upgraded biogas, featuring O/C between 0.2 and 1.2. Tracing these cases, at 800 °C and 500 mA/cm"2 constant load, cell performances are measured over a time interval of 100 h. Finally, post-mortem analysis is performed on the specimens to investigate material morphological changes after the exposure to high-methane fuels. Results showed that O/C = 0.8 (+63% air) is the best case to employ air-diluted natural gas

  11. Enhancing Sulfur Tolerance of Ni-Based Cermet Anodes of Solid Oxide Fuel Cells by Ytterbium-Doped Barium Cerate Infiltration.

    Science.gov (United States)

    Li, Meng; Hua, Bin; Luo, Jing-Li; Jiang, San Ping; Pu, Jian; Chi, Bo; Li, Jian

    2016-04-27

    Conventional anode materials for solid oxide fuel cells (SOFCs) are Ni-based cermets, which are highly susceptible to deactivation by contaminants in hydrocarbon fuels. Hydrogen sulfide is one of the commonly existed contaminants in readily available natural gas and gasification product gases of pyrolysis of biomasses. Development of sulfur tolerant anode materials is thus one of the critical challenges for commercial viability and practical application of SOFC technologies. Here we report a viable approach to enhance substantially the sulfur poisoning resistance of a Ni-gadolinia-doped ceria (Ni-GDC) anode through impregnation of proton conducting perovskite BaCe0.9Yb0.1O3-δ (BCYb). The impregnation of BCYb nanoparticles improves the electrochemical performance of the Ni-GDC anode in both H2 and H2S containing fuels. Moreover, more importantly, the enhanced stability is observed in 500 ppm of H2S/H2. The SEM and XPS analysis indicate that the infiltrated BCYb fine particles inhibit the adsorption of sulfur and facilitate sulfur removal from active sites, thus preventing the detrimental interaction between sulfur and Ni-GDC and the formation of cerium sulfide. The preliminary results of the cell with the BCYb+Ni-GDC anode in methane fuel containing 5000 ppm of H2S show the promising potential of the BCYb infiltration approach in the development of highly active and stable Ni-GDC-based anodes fed with hydrocarbon fuels containing a high concentration of sulfur compounds.

  12. Investigations of the oxidation-induced service life of chromium steels for high temperature fuel cell application (SOFC); Untersuchungen zur oxidationsbedingten Lebensdauer von Chromstaehlen fuer die Anwendung in der Hochtemperaturbrennstoffzelle (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Ertl, S.T.

    2006-08-17

    The increasing energy consumption of future automobiles should be covered by a solid oxide fuel cell (SOFC) used as an additional energy supply (auxiliary power unit). The application of a SOFC with about 5 kW power in cars requires small size, low weight and an economic fabrication. To achieve this goal the interconnector and the metallic anode substrate (depending on an alternative concept of construction) should be manufactured out of thin Crofer22APU, a high chromium ferritic steel. The scale formation mechanisms on Crofer22APU sheets, wires and powder metallurgical produced foils of different thicknesses were investigated in several atmospheres of water vapour/hydrogen at 800 and 900 C, simulating the anode conditions. For scale characterization a number of conventional analysis techniques such as optical metallography, scanning electron microscopy and X-ray diffraction were used in combination with deflection testing in monofacial oxidation and two-stage oxidation studies using {sup 18}O and H{sub 2} {sup 18}O tracer. With these results a theoretical model for the determination of lifetime was developed for Crofer22APU components in simulated anode gas. It was found that the lifetime at a given temperature depends not only on the surface-to-volume ratio, but also on the geometry of the component (e.g. sheet or wire). The critical Cr content required for breakaway oxidation depends on microcrack formation in the surface oxide scale, which occurs on ridges of a sheet during thermal cycling. The development of a metallic interconnector and a metallic anode substrate requires measures to avoid interdiffusion between the alloy and the bordering nickel-YSZ (yttrium stabilized zirconia) cermet of the anode, or depending on the conception of the stack, the bordering nickel-YSZ cermet of the anode functional layer. Therefore the suitability of preoxidation layers after different preoxidation conditions was tested. It was found that the inhibition of the interdiffusion

  13. A comprehensive CFD model of anode-supported solid oxide fuel cells

    International Nuclear Information System (INIS)

    Jeon, Dong Hyup

    2009-01-01

    The two-dimensional comprehensive CFD model of anode-supported SOFCs operating at intermediate temperature has been presented. This model provides transport phenomena of gas species with electrochemical characteristics and micro-structural properties, and predicts SOFC performance. The mathematical model solves conservation of electrons and ions, continuity equation, conservation of momentum, conservation of mass, and conservation of energy. A continuum micro-scale model based on statistical properties together with a mole-based conservation model was employed. CFD technique was used to solve the set of governing equations. The cell performance was decomposed with contributions of each overpotential and was presented at several operating temperatures with analysis of effective diffusivity. It was found that the contribution of potential gain due to temperature rising was considerably high. However it became non-significant at high operating temperature due to decreasing of effective diffusivity in AFL. These results showed that the performance and the distributions of current density, overpotentials, and mole fractions of gas species have a strong dependence upon temperature. From these results, it was concluded that the conservation of energy should be accommodated in comprehensive SOFC model. Also the useful information for the effect of parameters on cell performance and transport phenomena was provided

  14. Power generation characteristics of tubular type SOFC by wet process

    Energy Technology Data Exchange (ETDEWEB)

    Tajiri, H.; Nakayama, T. [Kyushu Electric Power Company, Inc., Fukuoka (Japan); Kuroishi, M. [TOTO Ltd., Kanagawa (Japan)] [and others

    1996-12-31

    The development of a practical solid oxide fuel cell requires improvement of a cell performance and a cell manufacturing technology suitable for the mass production. In particular tubular type SOFC is thought to be superior in its reliability because its configuration can avoid the high temperature sealing and reduce the thermal stress resulting from the contact between cells. The authors have fabricated a tubular cell with an air electrode support by a wet processing technique, which is suitable for mass production in improving a power density. To enhance the power output of the module, the Integrated Tubular-Type (ITT) cell has been developed. This paper reports the performance of the single cells with various active anode areas and the bundle with series-connected 9-ITT cells with an active anode area of 840 cm{sup 2}.

  15. Feed-forward control of a solid oxide fuel cell system with anode offgas recycle

    Science.gov (United States)

    Carré, Maxime; Brandenburger, Ralf; Friede, Wolfgang; Lapicque, François; Limbeck, Uwe; da Silva, Pedro

    2015-05-01

    In this work a combined heat and power unit (CHP unit) based on the solid oxide fuel cell (SOFC) technology is analysed. This unit has a special feature: the anode offgas is partially recycled to the anode inlet. Thus it is possible to increase the electrical efficiency and the system can be operated without external water feeding. A feed-forward control concept which allows secure operating conditions of the CHP unit as well as a maximization of its electrical efficiency is introduced and validated experimentally. The control algorithm requires a limited number of measurement values and few deterministic relations for its description.

  16. Design and optimization of a combined fuel reforming and solid oxide fuel cell system with anode off-gas recycling

    International Nuclear Information System (INIS)

    Lee, Tae Seok; Chung, J.N.; Chen, Yen-Cho

    2011-01-01

    Highlights: → In this work, an analytical, parametric study is performed to evaluate the feasibility and performance of a combined fuel reforming and SOFC system. → Specifically the effects of adding the anode off-gas recycling and recirculation components and the CO 2 absorbent unit are investigated. → The AOG recycle ratio increases with increasing S/C ratio and the addition of AOG recycle eliminates the need for external water consumption. → The key finding is that for the SOFC operating at 900 deg. C with the steam to carbon ratio at 5 and no AOG recirculation, the system efficiency peaks. - Abstract: An energy conversion and management concept for a combined system of a solid oxide fuel cell coupled with a fuel reforming device is developed and analyzed by a thermodynamic and electrochemical model. The model is verified by an experiment and then used to evaluate the overall system performance and to further suggest an optimal design strategy. The unique feature of the system is the inclusion of the anode off-gas recycle that eliminates the need of external water consumption for practical applications. The system performance is evaluated as a function of the steam to carbon ratio, fuel cell temperature, anode off gas recycle ratio and CO 2 adsorption percentage. For most of the operating conditions investigated, the system efficiency starts at around 70% and then monotonically decreases to the average of 50% at the peak power density before dropping down to zero at the limiting current density point. From an engineering application point of view, the proposed combined fuel reforming and SOFC system with a range of efficiency between 50% and 70% is considered very attractive. It is suggested that the optimal system is the one where the SOFC operates around 900 deg. C with S/C ratio higher than 3, maximum CO 2 capture, and minimum AOG recirculation.

  17. Transport parameters of thin, supported cathode layers in solid oxide fuel cells (SOFCs); Transportparameter duenner, getraegerter Kathodenschichten der oxidkeramischen Brennstoffzelle

    Energy Technology Data Exchange (ETDEWEB)

    Wedershoven, Christian

    2010-12-22

    The aim of this work was to determine the transport properties of thin cathode layers, which are part of the composite layer of a fabricated anode-supported solid oxide fuel cell (SOFC). The transport properties of the anode and cathode have a significant influence on the electrochemical performance of a fuel cell stack and therefore represent an important parameter when designing fuel cell stacks. In order to determine the transport parameters of the cathode layers in a fabricated SOFC, it is necessary to permeate the thin cathode layer deposited on the gas-tight electrolyte with a defined gas transport. These thin cathode layers cannot be fabricated as mechanically stable single layers and cannot therefore be investigated in the diffusion and permeation experiments usually used to determine transport parameters. The setup of these experiments - particularly the sample holder - was therefore altered in this work. The result of this altered setup was a three-dimensional flow configuration. Compared to the conventional setup, it was no longer possible to describe the gas transport in the experiments with an analytical one-dimensional solution. A numerical solution process had to be used to evaluate the measurements. The new setup permitted a sufficiently symmetrical gas distribution and thus allowed the description of the transport to be reduced to a two-dimensional description, which significantly reduced the computational effort required to evaluate the measurements. For pressure-induced transport, a parametrized coherent expression of transport could be derived. This expression is equivalent to the analytical description of the transport in conventional measurement setups, with the exception of parameters that describe the geometry of the gas diffusion. In this case, a numerical process is not necessary for the evaluation. Using the transport parameters of mechanically stable anode substrates, which can be measured both in the old and the new setups, the old and

  18. Elementary kinetic modelling applied to solid oxide fuel cell pattern anodes and a direct flame fuel cell system

    Energy Technology Data Exchange (ETDEWEB)

    Vogler, Marcel

    2009-05-27

    In the course of this thesis a model for the prediction of polarisation characteristics of solid oxide fuel cells (SOFC) was developed. The model is based on an elementary kinetic description of electrochemical reactions and the fundamental conservation principles of mass and energy. The model allows to predict the current-voltage relation of an SOFC and offers ideal possibilities for model validation. The aim of this thesis is the identification of rate-limiting processes and the determination of the elementary pathway during charge transfer. The numerical simulation of experiments with model anodes allowed to identify a hydrogen transfer to be the most probable charge-transfer reaction and revealed the influence of diffusive transport. Applying the hydrogen oxidation kinetics to the direct flame fuel cell system (DFFC) showed that electrochemical oxidation of CO is possible based on the same mechanism. Based on the quantification of loss processes in the DFFC system, improvements on cell design, predicting 80% increase of efficiency, were proposed. (orig.)

  19. Avances en el desarrollo de interconectores metálicos de celdas SOFC

    Directory of Open Access Journals (Sweden)

    Alvarado-Flores, J.

    2013-08-01

    Full Text Available Interest in solid oxide fuel cells (SOFC stems from their higher efficiencies and lower levels of emitted pollutants, compared to traditional power production methods. Interconnects are a critical part in SOFC stacks, which connect cells in series electrically, and also separate air or oxygen at the cathode side from fuel at the anode side. Therefore, the requirements of interconnects are the most demanding, i.e., to maintain high electrical conductivity, good stability in both reducing and oxidizing atmospheres, and close thermal expansion coefficient (TEC match and good compatibility with other SOFC ceramic components. This paper reviewed the interconnect materials, and coatings for metallic interconnect materials in a SOFC cell.El interés en las celdas de combustible de óxido sólido (SOFC, se deriva de su alta eficiencia y la capacidad de tener un bajo nivel de emisiones contaminantes, en comparación con los métodos tradicionales de producción de energía. Los interconectores, son parte crítica del ordenamiento de una celda SOFC, debido a que conecta en serie las celdas y además, separa el aire u oxígeno (cátodo del combustible (ánodo. Por lo tanto, los requisitos del interconector son muy exigentes, por ejemplo, es necesario mantener conductividad eléctrica elevada, óptima estabilidad tanto en atmósferas reductoras como oxidantes y el coeficiente de expansión térmica (TEC, debe ser compatible con los otros componentes cerámicos de la celda SOFC. Este artículo, revisa los materiales de interconexión, y materiales de revestimiento para interconectores metálicos en una celda SOFC.

  20. LG Solid Oxide Fuel Cell (SOFC) Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Haberman, Ben [LG Fuel Cell Systems Inc., North Canton, OH (United States); Martinez-Baca, Carlos [LG Fuel Cell Systems Inc., North Canton, OH (United States); Rush, Greg [LG Fuel Cell Systems Inc., North Canton, OH (United States)

    2013-05-31

    This report presents a summary of the work performed by LG Fuel Cell Systems Inc. during the project LG Solid Oxide Fuel Cell (SOFC) Model Development (DOE Award Number: DE-FE0000773) which commenced on October 1, 2009 and was completed on March 31, 2013. The aim of this project is for LG Fuel Cell Systems Inc. (formerly known as Rolls-Royce Fuel Cell Systems (US) Inc.) (LGFCS) to develop a multi-physics solid oxide fuel cell (SOFC) computer code (MPC) for performance calculations of the LGFCS fuel cell structure to support fuel cell product design and development. A summary of the initial stages of the project is provided which describes the MPC requirements that were developed and the selection of a candidate code, STAR-CCM+ (CD-adapco). This is followed by a detailed description of the subsequent work program including code enhancement and model verification and validation activities. Details of the code enhancements that were implemented to facilitate MPC SOFC simulations are provided along with a description of the models that were built using the MPC and validated against experimental data. The modeling work described in this report represents a level of calculation detail that has not been previously available within LGFCS.

  1. Synthesis of modified calcium aluminate with lanthanum manganite (LSM) for possible use in solid oxide fuel cell (SOFC); Sintese de aluminato de calcio modificado com manganita de lantanio (LSM) para possivel utilizacao em celula combustivel de oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Veiga, F.C.T.; Jurado, J.; Sousa, V.C. de, E-mail: faili.cintia@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Escola de Engenharia. Departamento de Materiais; Cava, S.S. [Universidade Federal de Pelotas, RS (Brazil)

    2016-07-01

    The fuel cells solid oxide (SOFC) is made up of three basic elements: two electrodes, the anode and cathode and a conductive electrolyte ions. The objective of this work consists of calcium aluminate synthesis modified LSM in a 1: 1 by combustion synthesis method with a view to its use as a cathode in SOFC. The characterization of the post was carried out by the methods of XRD, TEM and EIS. After heat treatment at 1200°C/4 hours it was possible to obtain Ca0.5Sr1.5MnO4 and CaMnO2.56 phases. The material showed a semiconductor characteristics because with increasing temperature the electrical resistance value tends to decrease obtaining electrical conductivity greater than 10-6S / cm featuring an extrinsic semiconductor with an activation energy of 0.12. Therefore, with an activation energy value within the range of materials used for a SOFC cathodes. (author)

  2. Feasibility study for SOFC-GT hybrid locomotive power: Part I. Development of a dynamic 3.5 MW SOFC-GT FORTRAN model

    Science.gov (United States)

    Martinez, Andrew S.; Brouwer, Jacob; Samuelsen, G. Scott

    2012-09-01

    This work presents the development of a dynamic SOFC-GT hybrid system model applied to a long-haul freight locomotive in operation. Given the expectations of the rail industry, the model is used to develop a preliminary analysis of the proposed system's operational capability on conventional diesel fuel as well as natural gas and hydrogen as potential fuels in the future. It is found that operation of the system on all three of these fuels is feasible with favorable efficiencies and reasonable dynamic response. The use of diesel fuel reformate in the SOFC presents a challenge to the electrochemistry, especially as it relates to control and optimization of the fuel utilization in the anode compartment. This is found to arise from the large amount of carbon monoxide in diesel reformate that is fed to the fuel cell, limiting the maximum fuel utilization possible. This presents an opportunity for further investigations into carbon monoxide electrochemical oxidation and/or system integration studies where the efficiency of the fuel reformer can be balanced against the needs of the SOFC.

  3. EFFECT OF RHODIUM INFILTRATION ON THE MICROSTRUCTURE AND PERFORMANCE OF Ni/Ce0.8Gd0.2O2-δ CERMET ANODE FOR LOW TEMPERATURE SOLID OXIDE FUEL CELL

    Directory of Open Access Journals (Sweden)

    F. Torknik

    2016-03-01

    Full Text Available In order to further enhance the Ni/Ce 0.8Gd0.2O2-δ (Ni/GDC20 cermet anodic performance for low temperature solid oxide fuel cell (LT-SOFC, a study was conducted on the nanostructuring of NiO/GDC composite by only once wet-infiltration of rhodium chloride precursor. By using electrochemical impedance spectroscopy (EIS analysis, the effect of only one drop of Rh-infiltrating solution on the anodic polarization resistance was examined using symmetric Ni–GDC20|GDC20|Pt electrolyte-supported cell at 400-600 °C. Nanostructural evolution before and after H 2 reduction at 600 °C and also after anodic performance test was investigated by atomic force microscopy (AFM, field emission scanning electron microscopy (FE-SEM, and transmission electron microscopy (TEM techniques in comparison to the anode itself. Despite the fine distribution of Rh-infiltrated nanoparticles having average particle size of 11.7 nm, the results showed ineffectiveness and inability of the Rh nanoparticles to succeed in decreasing of anodic polarization resistance for H 2 oxidation reaction in LT-SOFC.

  4. On direct internal methane steam reforming kinetics in operating solid oxide fuel cells with nickel-ceria anodes

    Science.gov (United States)

    Thallam Thattai, A.; van Biert, L.; Aravind, P. V.

    2017-12-01

    Major operating challenges remain to safely operate methane fuelled solid oxide fuel cells due to undesirable temperature gradients across the porous anode and carbon deposition. This article presents an experimental study on methane steam reforming (MSR) global kinetics for single operating SOFCs with Ni-GDC (gadolinium doped ceria) anodes for low steam to carbon (S/C) ratios and moderate current densities. The study points out the hitherto insufficient research on MSR global and intrinsic kinetics for operating SOFCs with complete Ni-ceria anodes. Further, it emphasizes the need to develop readily applicable global kinetic models as a subsequent step from previously reported state-of-art and complex intrinsic models. Two rate expressions of the Power law (PL) and Langmuir-Hinshelwood (LH) type have been compared and based on the analysis, limitations of using previously proposed rate expressions for Ni catalytic beds to study MSR kinetics for complete cermet anodes have been identified. Firstly, it has been shown that methane reforming on metallic (Ni) current collectors may not be always negligible, contrary to literature reports. Both PL and LH kinetic models predict significantly different local MSR reaction rate and species partial pressure distributions along the normalized reactor length, indicating a strong need for further experimental verifications.

  5. Development of redox stable, multifunctional substrates for anode supported SOFCS

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Foghmoes, Søren Preben Vagn; Ramos, Tania

    2017-01-01

    Redox stable solid oxide fuel cells are beneficial in many aspects such as tolerance against system failures e.g fuel cut off and emergency shut down, but also allow for higher fuel utilization, which increases efficiency. State-ofthe-art Ni-cermet based anodes suffer from microstructural changes...... with a multifunctional anode support, the development of a two layer fuel electrode based on a redox stable strontium titanate layer for the electrochemically active layer and a redox stable Ni-YSZ support was pursued. Half-cells with well adhearing strontium titante anode layers on stateof-the-art Ni-YSZ cermet...... supports have been achieved. Redox tolerance of the half-cell depends could be increased by optimizing the redox stability of the cermet support....

  6. High-performance micro-solid oxide fuel cells fabricated on nanoporous anodic aluminum oxide templates

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Chang-Woo; Kim, Hyun-Mi; Kim, Ki-Bum [WCUHybrid Materials Program, Department of Materials Science and Engineering, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, 151-742 (Korea, Republic of); Son, Ji-Won; Lee, Jong-Ho; Lee, Hae-Weon [High Temperature Energy Materials Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul, 136-791 (Korea, Republic of)

    2011-03-22

    Micro-solid oxide fuel cells ({mu}-SOFCs) are fabricated on nanoporous anodic aluminum oxide (AAO) templates with a cell structure composed of a 600-nm-thick AAO free-standing membrane embedded on a Si substrate, sputter-deposited Pt electrodes (cathode and anode) and an yttria-stabilized zirconia (YSZ) electrolyte deposited by pulsed laser deposition (PLD). Initially, the open circuit voltages (OCVs) of the AAO-supported {mu}-SOFCs are in the range of 0.05 V to 0.78 V, which is much lower than the ideal value, depending on the average pore size of the AAO template and the thickness of the YSZ electrolyte. Transmission electron microscopy (TEM) analysis reveals the formation of pinholes in the electrolyte layer that originate from the porous nature of the underlying AAO membrane. In order to clog these pinholes, a 20-nm thick Al{sub 2}O{sub 3} layer is deposited by atomic layer deposition (ALD) on top of the 300-nm thick YSZ layer and another 600-nm thick YSZ layer is deposited after removing the top intermittent Al{sub 2}O{sub 3} layer. Fuel cell devices fabricated in this way manifest OCVs of 1.02 V, and a maximum power density of 350 mW cm{sup -2} at 500 C. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Modeling of solid oxide fuel cells with particle size and porosity grading in anode electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L.; Flesner, R.; Kim, G.Y.; Chandra, A. [Department of Mechanical Engineering, Iowa State University, Ames, Iowa (United States)

    2012-02-15

    Solid oxide fuel cells (SOFCs) have the potential to meet the critical energy needs of our modern civilization and minimize the adverse environmental impacts from excessive energy consumption. They are highly efficient, clean, and can run on variety of fuel gases. However, little investigative focus has been put on optimal power output based on electrode microstructure. In this work, a complete electrode polarization model of SOFCs has been developed and utilized to analyze the performance of functionally graded anode with different particle size and porosity profiles. The model helps to understand the implications of varying the electrode microstructure from the polarization standpoint. The work identified conditions when grading can improve the cell performance and showed that grading is not always beneficial or necessary. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Reversible solid oxide fuel cells (R-SOFCs) with chemically stable proton-conducting oxides

    KAUST Repository

    Bi, Lei

    2015-07-01

    Proton-conducting oxides offer a promising way of lowering the working temperature of solid oxide cells to the intermediate temperate range (500 to 700. °C) due to their better ionic conductivity. In addition, the application of proton-conducting oxides in both solid oxide fuel cells (SOFCs) and sold oxide electrolysis cells (SOECs) provides unique advantages compared with the use of conventional oxygen-ion conducting conductors, including the formation of water at the air electrode site. Since the discovery of proton conduction in some oxides about 30. years ago, the development of proton-conducting oxides in SOFCs and SOECs (the reverse mode of SOFCs) has gained increased attention. This paper briefly summarizes the development in the recent years of R-SOFCs with proton-conducting electrolytes, focusing on discussing the importance of adopting chemically stable materials in both fuel cell and electrolysis modes. The development of electrode materials for proton-conducting R-SOFCs is also discussed. © 2015 Elsevier B.V.

  9. Methane Steam Reforming over an Ni-YSZ Solid Oxide Fuel Cell Anode in Stack Configuration

    Directory of Open Access Journals (Sweden)

    D. Mogensen

    2014-01-01

    Full Text Available The kinetics of catalytic steam reforming of methane over an Ni-YSZ anode of a solid oxide fuel cell (SOFC have been investigated with the cell placed in a stack configuration. In order to decrease the degree of conversion, a single cell stack with reduced area was used. Measurements were performed in the temperature range 600–800°C and the partial pressures of all reactants and products were varied. The obtained rates could be well fitted with a power law expression (r ∝PCH40.7. A simple model is presented which is capable of predicting the methane conversion in a stack configuration from intrinsic kinetics of the anode support material. The predictions are compared with the stack measurements presented here, and good agreement is observed.

  10. Multi-length scale tomography for the determination and optimization of the effective microstructural properties in novel hierarchical solid oxide fuel cell anodes

    Science.gov (United States)

    Lu, Xuekun; Taiwo, Oluwadamilola O.; Bertei, Antonio; Li, Tao; Li, Kang; Brett, Dan J. L.; Shearing, Paul R.

    2017-11-01

    Effective microstructural properties are critical in determining the electrochemical performance of solid oxide fuel cells (SOFCs), particularly when operating at high current densities. A novel tubular SOFC anode with a hierarchical microstructure, composed of self-organized micro-channels and sponge-like regions, has been fabricated by a phase inversion technique to mitigate concentration losses. However, since pore sizes span over two orders of magnitude, the determination of the effective transport parameters using image-based techniques remains challenging. Pioneering steps are made in this study to characterize and optimize the microstructure by coupling multi-length scale 3D tomography and modeling. The results conclusively show that embedding finger-like micro-channels into the tubular anode can improve the mass transport by 250% and the permeability by 2-3 orders of magnitude. Our parametric study shows that increasing the porosity in the spongy layer beyond 10% enhances the effective transport parameters of the spongy layer at an exponential rate, but linearly for the full anode. For the first time, local and global mass transport properties are correlated to the microstructure, which is of wide interest for rationalizing the design optimization of SOFC electrodes and more generally for hierarchical materials in batteries and membranes.

  11. Efficiency gain of solid oxide fuel cell systems by using anode offgas recycle - Results for a small scale propane driven unit

    Science.gov (United States)

    Dietrich, Ralph-Uwe; Oelze, Jana; Lindermeir, Andreas; Spitta, Christian; Steffen, Michael; Küster, Torben; Chen, Shaofei; Schlitzberger, Christian; Leithner, Reinhard

    The transfer of high electrical efficiencies of solid oxide fuel cells (SOFC) into praxis requires appropriate system concepts. One option is the anode-offgas recycling (AOGR) approach, which is based on the integration of waste heat using the principle of a chemical heat pump. The AOGR concept allows a combined steam- and dry-reforming of hydrocarbon fuel using the fuel cell products steam and carbon dioxide. SOFC fuel gas of higher quantity and quality results. In combination with internal reuse of waste heat the system efficiency increases compared to the usual path of partial oxidation (POX). The demonstration of the AOGR concept with a 300 Wel-SOFC stack running on propane required: a combined reformer/burner-reactor operating in POX (start-up) and AOGR modus; a hotgas-injector for anode-offgas recycling to the reformer; a dynamic process model; a multi-variable process controller; full system operation for experimental proof of the efficiency gain. Experimental results proof an efficiency gain of 18 percentage points (η·POX = 23%, η·AOGR = 41%) under idealized lab conditions. Nevertheless, further improvements of injector performance, stack fuel utilization and additional reduction of reformer reformer O/C ratio and system pressure drop are required to bring this approach into self-sustaining operation.

  12. Novel Mg-Doped SrMoO3 Perovskites Designed as Anode Materials for Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Vanessa Cascos

    2016-07-01

    Full Text Available SrMo1−xMxO3−δ (M = Fe and Cr, x = 0.1 and 0.2 oxides have been recently described as excellent anode materials for solid oxide fuel cells at intermediate temperatures (IT-SOFC with LSGM as the electrolyte. In this work, we have improved their properties by doping with aliovalent Mg ions at the B-site of the parent SrMoO3 perovskite. SrMo1−xMgxO3−δ (x = 0.1, 0.2 oxides have been prepared, characterized and tested as anode materials in single solid-oxide fuel cells, yielding output powers near 900 mW/cm−2 at 850 °C using pure H2 as fuel. We have studied its crystal structure with an “in situ” neutron power diffraction (NPD experiment at temperatures as high as 800 °C, emulating the working conditions of an SOFC. Adequately high oxygen deficiencies, observed by NPD, together with elevated disk-shaped anisotropic displacement factors suggest a high ionic conductivity at the working temperatures. Furthermore, thermal expansion measurements, chemical compatibility with the LSGM electrolyte, electronic conductivity and reversibility upon cycling in oxidizing-reducing atmospheres have been carried out to find out the correlation between the excellent performance as an anode and the structural features.

  13. AC impedance behavior of a practical-size single-cell SOFC under DC current

    Energy Technology Data Exchange (ETDEWEB)

    Momma, Akihiko; Kaga, Yasuo; Takano, Kiyonami; Nozaki, Ken; Negishi, Akira; Kato, Ken; Kato, Tohru [Fuel Cell Group, Energy Electronics Institute, National Institute of Advanced Industrial Science and Technology, Umezono Tsukuba-shi, Ibaraki 305-8568 (Japan); Inagaki, Toru; Yoshida, Hiroyuki [Energy Use R and D Center, The Kansai Electric Power Company, Inc., 11-20 Nakoji, 3-Chome, Amagasaki, Hyogo 661-0974 (Japan); Hosoi, Kei; Hoshino, Koji; Akbay, Taner; Akikusa, Jun; Yamada, Masaharu; Chitose, Norihisa [Central Research Institute, Naka Research Center, Mitsubishi Materials Corp. 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan)

    2004-10-29

    AC impedance measurements were carried out using practical-size planar disc-type SOFC which employs lanthanum gallate as a solid electrolyte. The data were obtained under practical conditions of gas flow rate and DC current. Under these conditions, the gas conversion impedance (GCI), which originates from the change of the electromotive force (EMF) caused by the change in anodic gaseous concentrations along the flow direction, was observed in the low-frequency range of the data obtained. The overlapping impedance together with GCI on the low-frequency arc was also estimated. Experimentally obtained GCI was in good agreement with that calculated. It was concluded that GCI was predominant in the impedance data obtained under practical conditions. The shift of the high-frequency intercept in the complex impedance diagrams was shown to appear as a result of the change in the distribution of gaseous composition in the anode. The dependency of the low-frequency arc on temperature was also shown, and it was assumed that the overlapped impedance varies as the temperature changes. The validity of the impedance measurement, as a diagnostic means to evaluate the gas flow in SOFC stack, was suggested.

  14. Alternative anode materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Goodenough, John B.; Huang, Yun-Hui [Texas Materials Institute, ETC 9.102, 1 University Station, C2200, The University of Texas at Austin, Austin, TX 78712 (United States)

    2007-11-08

    The electrolyte of a solid oxide fuel cell (SOFC) is an O{sup 2-}-ion conductor. The anode must oxidize the fuel with O{sup 2-} ions received from the electrolyte and it must deliver electrons of the fuel chemisorption reaction to a current collector. Cells operating on H{sub 2} 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 H{sub 2} bond; the oxidation of H{sub 2} to H{sub 2}O occurs at the Ni/electrolyte/H{sub 2} 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. (author)

  15. Parametric study of anodic microstructures to cell performance of planar solid oxide fuel cell using measured porous transport properties

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.M.; Shy, S.S.; Chien, C.W. [Department of Mechanical Engineering, National Central University, 300 Jhong-da Road, Jhong-li 32001 (China); Lee, C.H. [Institute of Nuclear Energy Research, Lung-tan, Tao-yuan 32546 (China)

    2010-04-15

    This study reports effects of porosity ({epsilon}), permeability (k) and tortuosity ({tau}) of anodic microstructures to peak power density (PPD) of a single-unit planar anode-supported SOFC based on 3D electrochemical flow models using measured porous transport properties. Applying particle image velocimetry, a transparent porous rib-channel with different {epsilon} is applied to measure an effective viscosity ({mu}{sub e}) in the Brinkman equation commonly used to predict flow properties in porous electrodes. It is found that, contrary to the popular scenario, {mu}{sub e} is not equal to the fluid viscosity ({mu}{sub f}), but it is several orders in magnitude smaller than {mu}{sub f} resulting in more than 10% difference on values of PPD. Numerical analyses show: (1) while keeping k and {tau} fixed with {epsilon} varying from 0.2 to 0.6, the highest PPD occurs at {epsilon} = 0.3 where the corresponding triple-phase-boundary length is a maximum; (2) PPD increases slightly with k when k{<=}10{sup -11} m{sup 2} due to the diffusion limitation in anode; and (3) PPD decreases with {tau} when {tau}>1.5 due to the accumulation of non-depleted products. Hence, a combination of {epsilon}=0.3, k=10{sup -11}m{sup 2}, and {tau}=1.5 is suggested for achieving higher cell performance of planar SOFC. (author)

  16. Solid oxide fuel cells and hydrogen production

    International Nuclear Information System (INIS)

    Dogan, F.

    2009-01-01

    'Full text': A single-chamber solid oxide fuel cell (SC-SOFC), operating in a mixture of fuel and oxidant gases, provides several advantages over the conventional SOFC such as simplified cell structure (no sealing required). SC-SOFC allows using a variety of fuels without carbon deposition by selecting appropriate electrode materials and cell operating conditions. The operating conditions of single chamber SOFC was studied using hydrocarbon-air gas mixtures for a cell composed of NiO-YSZ / YSZ / LSCF-Ag. The cell performance and catalytic activity of the anode was measured at various gas flow rates. The results showed that the open-circuit voltage and the power density increased as the gas flow rate increased. Relatively high power densities up to 660 mW/cm 2 were obtained in a SC-SOFC using porous YSZ electrolytes instead of dense electrolytes required for operation of a double chamber SOFC. In addition to propane- or methane-air mixtures as a fuel source, the cells were also tested in a double chamber configuration using hydrogen-air mixtures by controlling the hydrogen/air ratio at the cathode and the anode. Simulation of single chamber conditions in double chamber configurations allows distinguishing and better understanding of the electrode reactions in the presence of mixed gases. Recent research efforts; the effect of hydrogen-air mixtures as a fuel source on the performance of anode and cathode materials in single-chamber and double-chamber SOFC configurations,will be presented. The presentation will address a review on hydrogen production by utilizing of reversible SOFC systems. (author)

  17. High Performance Infiltrated Backbones for Cathode-Supported SOFC's

    DEFF Research Database (Denmark)

    Gil, Vanesa; Kammer Hansen, Kent

    2014-01-01

    The concept of using highly ionic conducting backbones with subsequent infiltration of electronically conducting particles has widely been used to develop alternative anode-supported SOFC's. In this work, the idea was to develop infiltrated backbones as an alternative design based on cathode......, microstructural characterization and electrochemical testing are discussed. Data on polarization resistance, Rp, are obtained from impedance spectra recorded on quasi-symmetrical cells (YSZ backbones/YSZ/LSM-YSZ (screen printed)). The backbones are infiltrated with LSM and compared to a standard LSM-YSZ screen...

  18. Co-extrusion of electrolyte/anode functional layer/anode triple-layer ceramic hollow fibres for micro-tubular solid oxide fuel cells-electrochemical performance study

    Science.gov (United States)

    Li, Tao; Wu, Zhentao; Li, K.

    2015-01-01

    In this study, the effects of an anode functional layer (AFL) with controlled thickness on physical and electrochemical properties of a micro-tubular SOFC have been systematically studied. A series of electrolyte/AFL/anode triple-layer hollow fibres with controllable AFL thicknesses (16.9-52.7 μm) have been fabricated via a single-step phase-inversion assisted co-extrusion technique. Both robustness of the cell and gas-tightness of the electrolyte layer are considerably improved by introducing the AFL of this type. The fracture force of the sample with the thickest AFL (9.67 N) almost doubles when compared to the electrolyte/anode dual-layer counterpart (5.24 N). Gas-tightness of the electrolyte layer is also considerably increased as AFL contributes to better-matched sintering behaviours between different components. Moreover, the formation of an AFL simultaneously with electrolyte and anode significantly improves the cell performances. The sample with the thinnest AFL (approximately 16.9 μm, 6% of the total anode thickness) leads to a 30% (from 0.89 to 1.21 W cm-2) increase in maximum power density, due to increased triple-phase boundaries (TPB). However, further increase in TPB from a thicker AFL is less effective for improving the cell performance, due to the substantially increased fuel diffusion resistance and subsequently higher concentration polarization. This indicates that the control over the AFL thickness is critically important in avoiding offsetting the benefits of extended TPB and consequently decreased cell performances.

  19. Biogas Catalytic Reforming Studies on Nickel-Based Solid Oxide Fuel Cell Anodes

    DEFF Research Database (Denmark)

    Johnson, Gregory B.; Hjalmarsson, Per; Norrman, Kion

    2016-01-01

    Heterogeneous catalysis studies were conducted on two crushed solid oxide fuel cell (SOFC) anodes in fixed-bed reactors. The baseline anode was Ni/ScYSZ (Ni/scandia and yttria stabilized zirconia), the other was Ni/ScYSZ modified with Pd/doped ceria (Ni/ScYSZ/Pd-CGO). Three main types......-programmed oxidation and time-of-flight secondary ion mass spectrometry. Results showed thatNi/ScYSZ/Pd-CGO was more active for catalytic dissociation of CH4 at 750°C and subsequent reactivity of deposited carbonaceous species. Sulfur deactivated most catalytic reactions except CO2 dissociation at 750°C. The presence...... of Pd-CGO helped to mitigate sulfur deactivation effect; e.g. lowering the onset temperature (up to 190°C) for CH4 conversion during temperature-programmed reactions. Both Ni/ScYSZ and Ni/ScYSZ/Pd-CGO anode catalysts were more active for dry reforming of biogas than they were for steam reforming...

  20. Performance Factors and Sulfur Tolerance of Metal Supported Solid Oxide Fuel Cells with Nanostructured Ni:GDC Infiltrated Anodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Persson, Åsa Helen; Sudireddy, Bhaskar Reddy

    2015-01-01

    poisoning. The ceria can be incorporated as a Ni:GDC cermet anode, but also via infiltration of ceria and doped ceria into the conventional Ni:YSZ cermet anode. Both approaches have been reported to improve the tolerance towards sulfur poisoning [1-3]. In the present study we report the performance...... concentrations of 2, 5 and 10 ppm in hydrogen fuel, during galvanostatic operation at a current load of 0.25 Acm-2. The results are illustrated and compared with the conventional SOFC Ni:YSZ cermet anode in figure 1, where the relative increase in anode polarization resistance as a function of Ni sulfur coverage...... is shown. The comparison indicate the MS-SOFC anode of the present study to be more tolerant towards sulfur poisoning than the conventional Ni:YSZ cermet anode. [1] K. Sasaki et al., J. Electrochem. Soc., 153, A2023–A2029 (2006). [2] L. Zhang et al., International Journal of Hydrogen Energy, 35, 12359...

  1. Testing of a cathode fabricated by painting with a brush pen for anode-supported tubular solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Renzhu; Zhao, Chunhua; Li, Junliang; Wang, Shaorong; Wen, Zhaoyin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

    2010-01-15

    We have studied the properties of a cathode fabricated by painting with a brush pen for use with anode-supported tubular solid oxide fuel cells (SOFCs). The porous cathode connects well with the electrolyte. A preliminary examination of a single tubular cell, consisting of a Ni-YSZ anode support tube, a Ni-ScSZ anode functional layer, a ScSZ electrolyte film, and a LSM-ScSZ cathode fabricated by painting with a brush pen, has been carried out, and an improved performance is obtained. The ohmic resistance of the cathode side clearly decreases, falling to a value only 37% of that of the comparable cathode made by dip-coating at 850 C. The single cell with the painted cathode generates a maximum power density of 405 mW cm{sup -2} at 850 C, when operating with humidified hydrogen. (author)

  2. Electrochemical Characterization of Ni/ScYSZ Electrodes as SOFC Anodes

    DEFF Research Database (Denmark)

    Ramos, Tania; Søgaard, Martin; Mogensen, Mogens Bjerg

    2014-01-01

    Investigations of Ni/ScYSZ cermets were performed by electrochemical impedance spectroscopy (EIS) using different symmetric designs: electrolyte supported (ESC) and anode supported (ASC) cells. The obtained spectra were analyzed using distribution of relaxation times (DRT), and complex non......-linear least squares fitting (CNLS). Depending on the cell design, one or two low frequency gas transport related processes have been identified, and fitted with generalized finite Warburg (GFW) elements. One was related to gas diffusion in a stagnant layer above the anode (ESC+ASC), and the other to gas...... diffusion in the anode support layer (ASC). A higher frequency process has also been identified, and correlated to the charge transfer (CT) combined with ionic conduction in the ceramic matrix. This has been fitted using a transmission line model (TML), which correlates the exhibited responses...

  3. Technical development and economic valuation of new cooling methods for planar solid oxide fuel cells (SOFC)

    International Nuclear Information System (INIS)

    Thom, F.

    2002-02-01

    A great potential exists for the use of the solid oxide fuel cell technology based on the planar cell design concept. Besides its application as power provider there is a need to supply process heat in the temperature range of 200 to 1200 C for commercial and industrial decentralized facilities. The present study is concerned with the technical development and economic valuation of plant concepts of new fuel cell cooling methods. They can be considered as an alternative to the normal convective cell cooling with air. Besides experimental studies on the natural gas reforming with the SOFC special attention is paid to the process analysis of the power plant carried out with the simulating program PROII. The 200 kWe SOFC is linked with peripheral components such as prereformer, heat exchangers, compressors etc. Developed program subroutine serve to calculate the electrical power output of the fuel cell, the investment costs and the costs of electricity. The study shows clearly that a radiative cell cooling device on basis of an external arranged vaporizer has economic benefits in comparison with the normal air cooling. In this case the possibility is given to run the fuel cell with completely prereformed natural gas. When the internal methane reforming is carried out in excess of the electrochemical demand for hydrogen and carbon monoxide respectively a further cost reduction potential is given. The produced synthesis gas can be used in alternative to the production of power in a gas turbine to supply process steam in the temperature range of 200 to 1200 C. Sensitivity analyses show that a successive use of optimization potentials (e.g. anode structure and operating parameters of the SOFC) leads to a further reduction of the costs of electricity. In the best case the achieved costs of 12 to 13 Pf/kWh are in a range achieved by CHP plants based on engines. (orig.) [de

  4. Preparation and Characterization of Anode-Supported YSZ Thin Film Electrolyte by Co-Tape Casting and Co-Sintering Process

    International Nuclear Information System (INIS)

    Liu, Q L; Fu, C J; Chan, S H; Pasciak, G

    2011-01-01

    In this study, a co-tape casting and co-sintering process has been developed to prepare yttria-stabilized zirconia (YSZ) electrolyte films supported on Ni-YSZ anode substrates in order to substantially reduce the fabrication cost of solid oxide fuel cells (SOFC). Through proper control of the process, the anode/electrolyte bilayer structures with a size of 7.8cm x 7.8cm were achieved with good flatness. Scanning electron microscopy (SEM) observation indicated that the YSZ electrolyte film was about 16 μm in thickness, highly dense, crack free and well-bonded to the anode support. The electrochemical properties of the prepared anode-supported electrolyte film was evaluated in a button cell mode incorporating a (LaSr)MnO 3 -YSZ composite cathode. With humidified hydrogen as the fuel and stationary air as the oxidant, the cell demonstrated an open-circuit voltage of 1.081 V and a maximum power density of 1.01 W/cm 2 at 800 deg. C. The obtained results represent the important progress in the development of anode-supported intermediate temperature SOFC with reduced fabrication cost.

  5. Preparation and Characterization of Anode-Supported YSZ Thin Film Electrolyte by Co-Tape Casting and Co-Sintering Process

    Science.gov (United States)

    Liu, Q. L.; Fu, C. J.; Chan, S. H.; Pasciak, G.

    2011-06-01

    In this study, a co-tape casting and co-sintering process has been developed to prepare yttria-stabilized zirconia (YSZ) electrolyte films supported on Ni-YSZ anode substrates in order to substantially reduce the fabrication cost of solid oxide fuel cells (SOFC). Through proper control of the process, the anode/electrolyte bilayer structures with a size of 7.8cm × 7.8cm were achieved with good flatness. Scanning electron microscopy (SEM) observation indicated that the YSZ electrolyte film was about 16 μm in thickness, highly dense, crack free and well-bonded to the anode support. The electrochemical properties of the prepared anode-supported electrolyte film was evaluated in a button cell mode incorporating a (LaSr)MnO3-YSZ composite cathode. With humidified hydrogen as the fuel and stationary air as the oxidant, the cell demonstrated an open-circuit voltage of 1.081 V and a maximum power density of 1.01 W/cm2 at 800°C. The obtained results represent the important progress in the development of anode-supported intermediate temperature SOFC with reduced fabrication cost.

  6. Development of Carbon and Sulphur Tolerant Anodes of Solid Oxide Fuel Cells

    Science.gov (United States)

    2010-01-14

    Thus, in this Chapter we report a detail study of the electrode behavior of pure Ni/GDC and Ni/YSZ cermet anodes in weakly humidified H2 fuel...impedance behavior for the oxidation reaction in hydrogen, methane and ethanol over a pure and Pd-impregnated Ni/GDC anode of SOFC were also studied ...surfaces [1]. So Ni/YSZ based cermet anodes have a very low tolerance to fuels containing H2S even at a very low level (ppm) [2]. Thus, the development of

  7. Air plasma spray processing and electrochemical characterization of Cu-SDC coatings for use in solid oxide fuel cell anodes

    Energy Technology Data Exchange (ETDEWEB)

    Benoved, Nir [Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Sciences Lane, Vancouver, British Columbia (Canada); Kesler, O. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario (Canada)

    2009-09-05

    Air plasma spraying has been used to produce porous composite anodes based on Ce{sub 0.8}Sm{sub 0.2}O{sub 1.9} (SDC) and Cu for use in solid oxide fuel cells (SOFCs). Preliminarily, a range of plasma conditions has been examined for the production of composite coatings from pre-mixed SDC and CuO powders. Plasma gas compositions were varied to obtain a range of plasma temperatures. After reduction in H{sub 2}, coatings were characterized for composition and microstructure using EDX and SEM. As a result of these tests, symmetrical sintered electrolyte-supported anode-anode cells were fabricated by air plasma spraying of the anodes, followed by in situ reduction of the CuO to Cu. Full cells deposited on SS430 porous substrates were then produced in one integrated process. Fine CuO and SDC powders have been used to produce homogeneously mixed anode coatings with higher surface area microstructures, resulting in area-specific polarization resistances of 4.8 {omega} cm{sup 2} in impedance tests in hydrogen at 712 C. (author)

  8. Air plasma spray processing and electrochemical characterization of Cu-SDC coatings for use in solid oxide fuel cell anodes

    Science.gov (United States)

    Benoved, Nir; Kesler, O.

    Air plasma spraying has been used to produce porous composite anodes based on Ce 0.8Sm 0.2O 1.9 (SDC) and Cu for use in solid oxide fuel cells (SOFCs). Preliminarily, a range of plasma conditions has been examined for the production of composite coatings from pre-mixed SDC and CuO powders. Plasma gas compositions were varied to obtain a range of plasma temperatures. After reduction in H 2, coatings were characterized for composition and microstructure using EDX and SEM. As a result of these tests, symmetrical sintered electrolyte-supported anode-anode cells were fabricated by air plasma spraying of the anodes, followed by in situ reduction of the CuO to Cu. Full cells deposited on SS430 porous substrates were then produced in one integrated process. Fine CuO and SDC powders have been used to produce homogeneously mixed anode coatings with higher surface area microstructures, resulting in area-specific polarization resistances of 4.8 Ω cm 2 in impedance tests in hydrogen at 712 °C.

  9. Detailed characterization of anode-supported SOFCs by impedance spectroscopy

    DEFF Research Database (Denmark)

    Barfod, R.; Mogensen, Mogens Bjerg; Klemensø, Trine

    2007-01-01

    Anode-supported thin electrolyte cells are studied by electrochemical impedance spectroscopy (EIS). The aim is to describe how the losses of this type of cells are distributed at low current density (around open-circuit voltage) as a function of temperature. An equivalent circuit consisting...

  10. Performance evaluation of a fuel cell with NiO-YSV anode operating with natural gas; Avaliacao do desempenho de uma celula a combustivel com anodo de NiO YSZ operando com gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, Shayenne Diniz da; Vasconcelos, Carmel Suzarte Ayres; Lima, Luiz Rogerio Pinho de Andrade [Universidade Federal da Bahia (UFBa), Salvador, BA (Brazil). Escola Politecnica. Dept. de Ciencia e Tecnologia dos Materiais]. E-mail: shayennedn@yahoo.com.br

    2008-07-01

    Fuel cell is an electrochemical device that converts the chemical energy into electric energy. The natural gas, for its proven improvement in the income of the equipment in relation to other energy ones, has been very used to feed the solid oxide fuel cell (SOFC) in the generation of electric power. Ceramics of Yttria-stabilized zirconia had been used as electrolyte and when supported with nickel oxide they act as anode in the solid oxide fuel cell, due to raised ionic conductivity that these materials present in high temperatures, while lanthanum with strontium and manganite are used as cathode. In the composition of the anode, the concentration of Ni O, acting as catalytic in the YSZ confers high electric conductivity and high electrochemical activity of the reactions, providing the internal reform in the SOFC. In this work, the solid oxide fuel cell, formed by Yttria- stabilized zirconia, nickel oxide, and lanthanum with strontium and manganite were tested in the reform had been prepared samples of electrode/electrolyte for use in SOFC of the natural gas in the presence of low water text, similar condition to the operation of the SOFC, operating in temperatures range from 700 to 800 deg C. This cell also was characterized using the impedance spectroscopy technique. These results allowed the development of components of the current versus voltage. (author)

  11. Rational Design of a Water-Storable Hierarchical Architecture Decorated with Amorphous Barium Oxide and Nickel Nanoparticles as a Solid Oxide Fuel Cell Anode with Excellent Sulfur Tolerance.

    Science.gov (United States)

    Song, Yufei; Wang, Wei; Ge, Lei; Xu, Xiaomin; Zhang, Zhenbao; Julião, Paulo Sérgio Barros; Zhou, Wei; Shao, Zongping

    2017-11-01

    Solid oxide fuel cells (SOFCs), which can directly convert chemical energy stored in fuels into electric power, represent a useful technology for a more sustainable future. They are particularly attractive given that they can be easily integrated into the currently available fossil fuel infrastructure to realize an ideal clean energy system. However, the widespread use of the SOFC technology is hindered by sulfur poisoning at the anode caused by the sulfur impurities in fossil fuels. Therefore, improving the sulfur tolerance of the anode is critical for developing SOFCs for use with fossil fuels. Herein, a novel, highly active, sulfur-tolerant anode for intermediate-temperature SOFCs is prepared via a facile impregnation and limited reaction protocol. During synthesis, Ni nanoparticles, water-storable BaZr 0.4 Ce 0.4 Y 0.2 O 3- δ (BZCY) perovskite, and amorphous BaO are formed in situ and deposited on the surface of a Sm 0.2 Ce 0.8 O 1.9 (SDC) scaffold. More specifically, a porous SDC scaffold is impregnated with a well-designed proton-conducting perovskite oxide liquid precursor with the nominal composition of Ba(Zr 0.4 Ce 0.4 Y 0.2 ) 0.8 Ni 0.2 O 3- δ (BZCYN), calcined and reduced in hydrogen. The as-synthesized hierarchical architecture exhibits high H 2 electro-oxidation activity, excellent operational stability, superior sulfur tolerance, and good thermal cyclability. This work demonstrates the potential of combining nanocatalysts and water-storable materials in advanced electrocatalysts for SOFCs.

  12. Nanostructured palladium-La{sub 0.75}Sr{sub 0.25}Cr{sub 0.5}Mn{sub 0.5}O{sub 3}/Y{sub 2}O{sub 3}-ZrO{sub 2} composite anodes for direct methane and ethanol solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, San Ping; Ye, Yinmei; He, Tianmin; Ho, See Boon [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2008-10-15

    A palladium-impregnated La{sub 0.75}Sr{sub 0.25}Cr{sub 0.5}Mn{sub 0.5}O{sub 3-{delta}}/yttria-stabilized zirconia (LSCM/YSZ) composite anode is investigated for the direct utilization of methane and ethanol fuels in solid oxide fuel cells (SOFCs). Impregnation of Pd nanoparticles significantly enhances the electrocatalytic activity of LSCM/YSZ composite anodes for the methane and ethanol electrooxidation reaction. At 800 C, the maximum power density is increased by two and eight times with methane and ethanol fuels, respectively, for a cell with the Pd-impregnated LSCM/YSZ composite anode, as compared with that using a pure LSCM/YSZ anode. No carbon deposition is observed during the reaction of methane and ethanol fuels on the Pd-impregnated LSCM/YSZ composite anode. The results show the promises of nanostructured Pd-impregnated LSCM/YSZ composites as effective anodes for direct methane and ethanol SOFCs. (author)

  13. A novel design of anode-supported solid oxide fuel cells with Y 2O 3-doped Bi 2O 3, LaGaO 3 and La-doped CeO 2 trilayer electrolyte

    Science.gov (United States)

    Guo, Weimin; Liu, Jiang

    Anode-supported solid oxide fuel cells (SOFCs) with a trilayered yttria-doped bismuth oxide (YDB), strontium- and magnesium-doped lanthanum gallate (LSGM) and lanthanum-doped ceria (LDC) composite electrolyte film are developed. The cell with a YDB (18 μm)/LSGM (19 μm)/LDC (13 μm) composite electrolyte film (designated as cell-A) shows the open-circuit voltages (OCVs) slightly higher than that of a cell with an LSGM (31 μm)/LDC (17 μm) electrolyte film (designated as cell-B) in the operating temperature range of 500-700 °C. The cell-A using Ag-YDB composition as cathode exhibits lower polarization resistance and ohmic resistance than those of a cell-B at 700 °C. The results show that the introduction of YDB to an anode-supported SOFC with a LSGM/LDC composite electrolyte film can effectively block electronic transport through the cell and thus increased the OCVs, and can help the cell to achieve higher power output.

  14. Binary co-generative plants with height temperature SOFC fuel cells

    International Nuclear Information System (INIS)

    Tashevski, D; Dimitrov, K.; Armenski, S.

    2005-01-01

    In this paper, a field of binary co-generative plants with height temperature SOFC fuel cells is presented. Special attention of application of height temperature SOFC fuel cells and binary co-generative units has been given. These units made triple electricity and heat. Principle of combination of fuel cells with binary cycles has been presented. A model and computer programme for calculation of BKPFC, has been created. By using the program, all the important characteristic-results are calculated: power, efficiency, emission, dimension and economic analysis. On base of results, conclusions and recommendations has been given. (Author)

  15. Binary co-generative plants with height temperature SOFC fuel cells

    International Nuclear Information System (INIS)

    Tashevski, D; Dimitrov, K.; Armenski, S.

    2006-01-01

    In this paper, a field of binary co-generative plants with height temperature SOFC fuel cells is presented. Special attention of application of height temperature SOFC fuel cells and binary co-generative units has been given. These units made triple electricity and heat. Principle of combination of fuel cells with binary cycles has been presented. A model and computer programme for calculation of BKPFC, has been created. By using the program, all the important characteristic-results are calculated: power, efficiency, emission, dimension and economic analysis. On base of results, conclusions and recommendations has been given. (Author)

  16. Fiscal 2000 project of inviting proposals for international joint research - invitation for international proposal (Power generation No.2). Achievement report on development of high-efficiency low-temperature power generation device using SOFC containing yttria-doped ceria layer; 2000 nendo kokusai kyodo kenkyu teian kobo jigyo - kokusai teian kobo (hatsuden No.2). Yttria gan'yu ceria so wo yusuru SOFC kokoritsu teion sadogata hatsuden sochi no kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Efforts continue to develop a solid oxide fuel cell (SOFC) capable of consuming methane, propane, and the like, as fuel directly and of operation at 650 degrees C or lower. The efforts in concrete terms involve the development of an anode material, an electrolyte, and a cathode material not to suffer carbon precipitation and the evaluation of power generation performance of a hydrocarbon fueled single cell. Activities are conducted in the five domains of (1) the fabrication of an SOFC single cell and a preliminary study, (2) evaluation of solid electrolyte thermal stability using X-ray diffraction, (3) anodic carbon precipitation test and single cell performance test, (4) survey of technical trends overseas, and (5) the goal and self-management. In domain (1), technologies are developed to form thin film anodes of Ni-GDC (gadolinium-doped ceria), Cu-GDC, Ni-YSZ (yttria-stabilized zirconia), and the like, for which the ultrasonic spray method and slurry coat method are used. In the study of cell manufacturing, the anode support method and cathode support method are investigated. The anode support method is used to fabricate a thin film, a thin YSZ film is successfully fabricated for typical Ni-YSZ. (NEDO)

  17. Determination of global and local residual stresses in SOFC by X-ray diffraction

    International Nuclear Information System (INIS)

    Villanova, Julie; Sicardy, Olivier; Fortunier, Roland; Micha, Jean-Sebastien; Bleuet, Pierre

    2010-01-01

    Solid Oxide Fuel Cell (SOFC) is a high-performance electrochemical device for energy conversion. A single cell is composed of five layers made of different ceramic materials: anode support, anode functional layer, electrolyte, cathode functional layer and cathode. The mechanical integrity of the cell is a major issue during its lifetime, especially for the electrolyte layer. Damage of the cells is mainly due to the high operating temperature, the 'redox' behaviour of the anode and the brittleness of the involved materials. Since residual stresses are known to play a significant role in the damage evolution, it is important to determine them. For this purpose, residual stresses in an anode-supported planar SOFC were measured by X-ray diffraction. Firstly, macroscopic stresses in each phase of each layer were studied using the sin 2 ψ method on a laboratory X-ray goniometer at room temperature. This technique enables the calculation of residual stress of the material from the measurement of the crystal lattice deformation. The electrolyte has been found under bi-axial compressive stress of -920 MPa. Secondly, X-ray measurements controlling depth penetration were made in the electrolyte using grazing incidence method. The results show that the stress is not homogenous in the layer. The first five micrometers of the electrolyte have been found less constrained (-750 MPa) than the complete layer, suggesting a gradient of deformation in the electrolyte from the interface with the Anode Functional Layer to the free surface. Finally, local stress measurements were made on the electrolyte layer by X-ray synchrotron radiation that allows high accuracy measurement on the (sub-) micrometer scale. Polychromatic and monochromatic beams are used to determine the complete strain tensor from grain to grain in the electrolyte. First results confirm the macroscopic stress trend of the electrolyte. These X-ray techniques at different scales will contribute to a better understanding

  18. Solid oxide fuel cell bi-layer anode with gadolinia-doped ceria for utilization of solid carbon fuel

    Energy Technology Data Exchange (ETDEWEB)

    Kellogg, Isaiah D. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, 290A Toomey Hall, 400 West 13th Street, Rolla, MO 65409 (United States); Department of Materials Science and Engineering, Missouri University of Science and Technology, 223 McNutt Hall, 1400 N. Bishop, Rolla, MO 65409 (United States); Koylu, Umit O. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, 290A Toomey Hall, 400 West 13th Street, Rolla, MO 65409 (United States); Dogan, Fatih [Department of Materials Science and Engineering, Missouri University of Science and Technology, 223 McNutt Hall, 1400 N. Bishop, Rolla, MO 65409 (United States)

    2010-11-01

    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. (author)

  19. Heat and mass transfer analysis intermediate temperature solid oxide fuel cells (IT-SOFC)

    International Nuclear Information System (INIS)

    Timurkutluk, B.; Mat, M. M.; Kaplan, Y.

    2007-01-01

    Solid oxide fuel cells (SOFCs) have been considered as next generation energy conversion system due to their high efficiency, clean and quite operation with fuel flexibility. To date, yittria stabilized zirconia (YSZ) electrolytes have been mainly used for SOFC applications at high temperatures around 1000 degree C because of their high ionic conductivity, chemical stability and good mechanical properties. However, such a high temperature is undesirable for fuel cell operations in the viewpoint of stability. Moreover, high operation temperature necessitates high cost interconnect and seal materials. Thus, the reduction in the operation temperature of SOFCs is one of the key issues in the aspects of the cost reduction and the long term operation without degradation as well as commercialization of the SOFC systems. With the reducing temperature, not only low cost stainless steels and glass materials can be used as interconnect and sealing materials respectively but the manufacturing technology will also extend. Therefore, the design of complex geometrical SOFC component will also be possible. One way to reduce the operation temperature of SOFC is use of an alternative electrolyte material to YSZ showing acceptable properties at intermediate temperatures (600-800 degree C). As being one of IT-SOFC electrolyte materials, gadolinium doped ceria (GDC) has been taken great deals. In this study, a mathematical model for mass and heat transfer for a single cell GDC electrolyte SOFC system was developed and numerical solutions were evaluated. In order to verify the mathematical model, set of experiments were performed by taking species from four different samples randomly and five various temperature measurements. The numerical results reasonably agree with experimental data

  20. Effect of the co-spun anode functional layer on the performance of the direct-methane microtubular solid oxide fuel cells

    Science.gov (United States)

    Meng, Xiuxia; Gong, Xun; Yin, Yimei; Yang, Naitao; Tan, Xiaoyao; Ma, Zi-Feng

    2014-02-01

    NiO-YSZ/porous YSZ (NiO-YSZ/p-YSZ) dual-layer hollow fibers have been fabricated by a co-spinning-sintering method, on which a dense YSZ films has been formed by a dip-coating and sintering process. A LSM-YSZ ink has been dip-coated on the dense YSZ films as cathode, while the Cu-CeO2 carbon-resistant catalyst has been impregnated in the p-YSZ layer to form double-anode supported micro tubular fuel cells (MT-SOFCs). The thickness of the Ni-YSZ layer, so called anode functional layer (AFL), is controlled from 74 μm to 13 μm by varying the spinning rates of the NiO-YSZ dopes. The maximum power density of an MT-SOFC, which is fabricated based on a thin co-spun AFL, reaches 566 mW cm-2 operated at 850 °C fed with dry methane, and is stably operated for 85 h without power declination.

  1. Thermoelectric characterization of an intermediate temperature solid oxide fuel cell system directly fed by dry biogas

    International Nuclear Information System (INIS)

    De Lorenzo, G.; Corigliano, O.; Lo Faro, M.; Frontera, P.; Antonucci, P.; Zignani, S.C.; Trocino, S.; Mirandola, F.A.; Aricò, A.S.; Fragiacomo, P.

    2016-01-01

    Highlights: • Numerical Model (NM) of SOFC Cogenerative System (SCS) fed by dry biogas is set up. • NM simulates new Ni-Fe/CGO protective layer for direct CH_4 consumption at the anode. • NM simulates the anode carbonation phenomenon and is experimentally validated. • The performance parameters trends of SCS fed by three types of dry biogas are shown. • SEM images after 40 h of operation show that there is no anode carbon deposition. - Abstract: A properly manufactured intermediate temperature Solid Oxide Fuel Cell (SOFC) can be directly fed by dry biogas, considering also the electrochemical partial and total oxidation reactions of methane in the biogas at the anode. In this way the methane in the biogas is electrochemically consumed directly at the fuel cell without the need to mix the biogas with any reforming gas (steam, oxygen or carbon dioxide). In this article, a numerical model of an SOFC system with Ni-Fe/CGO electrocatalyst anode protective layer directly fed by dry biogas, in cogenerative arrangement and with anode exhaust gas recirculation is formulated. The influences of biogas composition, of fuel cell operating current density and of percentage of recirculated anode exhaust gas on the SOFC system performances were evaluated by calculation code. An SOFC test bench was set up to validate the calculation code results experimentally. Furthermore, the numerical model also considers the anode carbonation and evaluates the amount of carbon that can be formed in the anode at chemical equilibrium and quasi-equilibrium conditions associated with the specific anode protective layer used.

  2. Effect of Humidity in Air on Performance and Long-Term Durability of SOFCs

    DEFF Research Database (Denmark)

    Hagen, Anke; Neufeld, Kai; Liu, Yi-Lin

    2010-01-01

    Anode-supported solid oxide fuel cells (SOFCs) based on Ni–yttria-stabilized zirconia (YSZ) anodes, YSZ electrolytes, and lanthanum strontium manganite (LSM)–YSZ cathodes were studied with respect to durability in humid air (~4%) typically over 1500 h. Operating temperature and current density were...... varied between 750 and 850°C and 0.25–0.75 A/cm2, respectively. The introduction of humidity affected the cell voltage under polarization of the cell, and this effect was (at least partly) reversible upon switching off the humidity. Generally, the studied cells were operated in humid air under...... technologically relevant conditions over more than 1500 h. Improvements at the cathode/electrolyte interface made it possible to obtain highly stable cells, which can be operated under high current density and at 750°C in humid air, conditions that cause significant cell voltage degradation in dry air on cells...

  3. Aspects of industrial production of solid electrolyte fuel cells (SOFC) by thermal spraying technology; Aspekte industrieller Fertigung von Festelektrolyt-Brennstoffzellen (SOFC) mittels thermischer Beschichtungsverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Weckmann, Hannes

    2010-07-01

    The present thesis deals with measures to optimize the large-volume production of Solid Oxide Fuel Cells (SOFC) based on thermal spraying technology. Based on the well-established Vacuum Plasma Spraying (VPS) at DLR the potential of alternative thermal spraying techniques as well as alternative base materials was investigated in order to deposit SOFC-anode, electrolyte and insulating layers. Production costs, reproducibility and long-term stability of the production process as well as the fuel cell performance were major target criteria. Depending on the parameter set applied when using the cost efficient Atmospheric Plasma Spraying (APS) in combination with Nickel-Graphite as base material a significant improvement of gas permeability and electrical conductivity was achieved in comparison to the VPS sprayed reference anode. The power density of a fuel cell with an APS-Nickel-Graphite anode (184 mW/cm{sup 2}) was slightly better than the performance with a VPS reference anode (159 mW/cm{sup 2}). In comparison to the VPS process, ceramic electrolyte layers of fully stabilized Zirconia (YSZ) with significantly higher gas tightness could be demonstrated when high energy processes such as Low Pressure Plasma Spraying (LPPS). Thin-film Low Pressure Plasma Spraying (LPPS-Thin-film) and High Velocity Oxy Fuel Spraying (HVOF) were applied. The power density of a fuel cell equipped with an HVOF electrolyte was significantly improved to 234 mW/cm{sup 2} as compared to 187 mW/cm{sup 2} with the VPS sprayed reference cell. Further improvement of the power density was achieved with an LPPS-electrolyte (273 mW/cm{sup 2}). HVOF and VPS sprayed layers of pure Spinel in composite with metallic active braze (equivalent to the sealing between individual layers in the fuel cell stack) could exceed the demanded charge transfer resistance of >1 k{omega}cm{sup 2} at 800 C operating temperature only in few cases. When blended base powder of Spinel and Magnesia in combination with the VPS

  4. Effective improvement of interface modified strontium titanate based solid oxide fuel cell anodes by infiltration with nano-sized palladium and gadolinium-doped cerium oxide

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain; Høgh, Jens Valdemar Thorvald; Zhang, Wei

    2013-01-01

    The development of low temperature solid oxide fuel cell (SOFC) anodes by infiltration of Pd/Gd-doped cerium oxide (CGO) electrocatalysts in Nb-doped SrTiO3 (STN) backbones has been investigated. Modification of the electrode/electrolyte interface by thin layer of spin-coated CGO (400-500 nm) con...

  5. SOFC mini-tubulares basadas en YSZ

    Directory of Open Access Journals (Sweden)

    Campana, R.

    2008-08-01

    Full Text Available Tubular SOFC have the advantage over planar SOFC of the low temperature sealing and more resistance to thermal shock. On the other hand the volumetric power density of tubular Fuel Cells goes with the inverse of the tube diameter which added to the faster warm-up kinetics makes low diameter tubular SOFC favorable for low power applications. Anode supported tubular SOFC of 3mm diameter and 150 mm length with YSZ electrolyte were fabricated and tested by V-I measurements using H2-Ar (5, 10, 100 vol% as fuel and air for the cathode. The NiO-YSZ tubes of about 400 μm thickness were produced by hydrostatic pressure and then coated with an YSZ film of 15-20 μm. The electrolyte was deposited using a manual aerograph. After sintering either Pt paste or LSF (with YSZ or SDC coatings of about 20-50 μm thickness were deposited for the cathode. The OCV of the cells were excellent, very close to the expected Nernst law prediction indicating that there were not gas leaks. The maximun electrical power of the cell was near to 500mW/cm2 at 850ºC operation temperature. Complex impedance measurements of the cells were performed in order to determine the resistance of the different cell components.

    La principal ventaja de las SOFC tubulares frente a las planares es el sellado de la cámara anódica y catódica a bajas temperaturas. Además la densidad de energía volumétrica de las pilas tubulares es inversamente proporcional al diámetro del tubo, que añadido a los tiempos cortos de encendido y apagado hacen que las mini-tubulares sean interesantes para usos de baja potencia. Se han fabricado y caracterizado SOFC tubulares soportadas en ánodo de 3mm de diámetro y de 150 mm de longitud, 400μm de espesor, con electrolito de YSZ depositado por spray de 15-20 μm. Los tubos de NiO-YSZ son producidos por prensado isostático. La caracterización eléctrica se ha realizado empleando H2-Ar como combustible an

  6. Development of Robust Metal-Supported SOFCs and Stack Components in EU METSAPP Consortium

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Nielsen, Jimmi; Persson, Åsa Helen

    2017-01-01

    METSAPP project has been executed with an overall aim of developing advanced metal-supported cells and stacks based on a robust, reliable and up-scalable technology. During the project, oxidation resistant nanostructured anodes based on modified SrTiO3 were developed and integrated into MS...... and best performance and stability combination was observed with doped SrTiO3 based anode designs. Furthermore, numerical models to understand the corrosion behavior of the MS-SOFCs were developed and validated. Finally, the cost effective concept of coated metal interconnects was developed, which resulted...... in 90% reduction in Cr evaporation, three times lower Cr2O3 scale thickness and increased lifetime. The possibility of assembling these cells into two radically different stack designs was demonstrated....

  7. Development of materials for use in solid oxid fuel cells anodes using renewable fuels in direct operation; Desenvolvimento de materiais ceramicos aplicados em anodos de celulas a combustivel de oxidos solidos para operacao direta com combustiveis renovaveis

    Energy Technology Data Exchange (ETDEWEB)

    Lima, D.B.P.L. de [Instituto Federal do Parana (IFPR), PR (Brazil); Florio, D.Z. de; Bezerra, M.E.O., E-mail: daniela.bianchi@ifpr.edu.br [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

    2016-07-01

    Fuel cells produce electrical current from the electrochemical combustion of a gas or liquid (H2, CH4, C2H5OH, CH3OH, etc.) inserted into the anode cell. An important class of fuel cells is the SOFC (Solid Oxide Cell Fuel). It has a ceramic electrolyte that transports protons (H +) or O-2 ions and operating at high temperatures (500-1000 °C) and mixed conductive electrodes (ionic and electronic) ceramics or cermets. This work aims to develop anodes for fuel cells of solid oxide (SOFC) in order to direct operations with renewable fuels and strategic for the country (such as bioethanol and biogas). In this context, it becomes important to study in relation to the ceramic materials, especially those that must be used in high temperatures. Some types of double perovskites such as Sr2MgMoO6 (or simply SMMO) have been used as anodes in SOFC. In this study were synthesized by the polymeric precursor method, analyzed and characterized different ceramic samples of families SMMO, doped with Nb, this is: Sr2 (MgMo)1-xNbxO6 with 0 ≤ x ≤ 0.2. The materials produced were characterized by various techniques such as, thermal analysis, X-ray diffraction and scanning electron microscopy, and electrical properties determined by dc and ac measurements in a wide range of temperature, frequency and partial pressure of oxygen. The results of this work will contribute to a better understanding of advanced ceramic properties with mixed driving (electronic and ionic) and contribute to the advancement of SOFC technology operating directly with renewable fuels. (author)

  8. Effect of anode firing on the performance of lanthanum and nickel co-doped SrTiO3 (La0.2Sr0.8Ti0.9Ni0.1O3-δ) anode of solid oxide fuel cell

    Science.gov (United States)

    Park, Byung Hyun; Choi, Gyeong Man

    2015-10-01

    Perovskite oxides have potential for use as alternative anode materials in solid oxide fuel cells (SOFCs) due to stability in anode atmosphere; donor-doped SrTiO3 (e.g., La0.2Sr0.8TiO3-δ) is a good candidate for this purpose. Electro-catalytic nanoparticles can be produced in oxide anodes by the ex-solution method, e.g., by incorporating Ni into a perovskite oxide in air, then reducing the oxide in H2 atmosphere. In this study, we varied the temperature (1100, 1250 °C) and atmosphere (air, H2) of La0.2Sr0.8Ti0.9Ni0.1O3-δ (LSTN) anode firing to control the degree of Ni ex-solution and microstructure. LSTN fired at 1250 °C in H2 showed the best anodic performance for scandia-stabilized zirconia (ScSZ) electrolyte-supported cells in H2 and CH4 fuels due to the favorable microstructure and Ni ex-solution.

  9. Sulfur poisoning of Ni/Gadolinium-doped ceria anodes: A long-term study outlining stable solid oxide fuel cell operation

    Science.gov (United States)

    Riegraf, Matthias; Zekri, Atef; Knipper, Martin; Costa, Rémi; Schiller, Günter; Friedrich, K. Andreas

    2018-03-01

    This work presents an analysis of the long-term behavior of nickel/gadolinium-doped ceria (CGO) anode-based solid oxide fuel cells (SOFC) under sulfur poisoning conditions. A parameter study of sulfur-induced irreversible long-term degradation of commercial, high-performance single cells was carried out at 900 °C for different H2/N2/H2S fuel gas atmospheres, current densities and Ni/CGO anodes. The poisoning periods of the cells varied from 200 to 1500 h. The possibility of stable long-term Ni/CGO anode operation under sulfur exposure is established and the critical operating regime is outlined. Depending on the operating conditions, two degradation phenomena can be observed. Small degradation of the ohmic resistance was witnessed for sulfur exposure times of approximately 1000 h. Moreover, degradation of the anode charge transfer resistance was observed to be triggered by the combination of a small anodic potential step and high sulfur coverage on Ni. The microstructural evolution of altered Ni/CGO anodes was examined post-mortem by means of SEM and FIB/SEM, and is correlated to the anode performance degradation under critical operating conditions, establishing Ni depletion, porosity increase and a tripe phase boundary density decrease in the anode functional layer. It is shown that short-term sulfur poisoning behavior can be used to assess long-term stability.

  10. Solid oxide fuel cells, SOFC, in future power generation; Fastoxidbraensleceller, SOFC, i framtida kraftgenerering

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Kent; Baafaelt, M

    1997-02-01

    Solid Oxide Fuel Cell, SOFC, is a very promising technological area for generating electricity in the future. Especially for small scale cogeneration. SOFC is an excellent choice due to its high efficiencies at small power plant sizes. The expected size of the power plants is 10-20 MWe but larger ones might be built. An important part of the assumptions in this report is the SOFC electric efficiency dependence of the pressure in the process. The electric efficiency is assumed to be 50% at atmospheric pressure and 55% at 10 atmospheres. These assumptions lead to a formula that describes the electric efficiency as a function of the pressure. The parametric study shows that the pressure has a very large influence of the electric efficiency. At low pressure and high Turbine Inlet Temperature (TIT) the electric efficiency will be higher than at high pressure and low TIT. The post intercooler temperature and the pressure drop over the SOFC unit have a moderate effect on the electric efficiency. In the process calculations the TIT is shown to have a very small influence on the plant efficiencies. Consequently, by lowering the TIT, the need for blade cooling and tougher materials can be avoided, with only a small electric efficiency decrease. The recuperator is a central part of the process. It evens out the influence from other parts in the process. This is one of the reasons why the polytropic efficiencies of the compressor and the expander have such a low influence on the process efficiency. The report shows that to receive high efficiencies in a SOFC/GT power plant, the points mentioned below should be taken into consideration: The pressure in the process should be approximately 4 bar; The compressor should have an intercooler; The TIT should be below the temperature where blade cooling is needed; No steam cycle should be connected after the gas turbine at sizes of 5-20 MW. 32 refs, 67 figs, 9 tabs, 15 appendices

  11. A solid oxide fuel cell with a gadolinia-doped ceria anode: Preparation and performance

    DEFF Research Database (Denmark)

    Marina, O.A.; Bagger, C.; Primdahl, S.

    1999-01-01

    ) electrolyte without detrimental reaction. Single SOFCs comprising the CG4 anode, a composite strontium-doped lanthanum manganite-based cathode and the YSZ electrolyte were manufactured and tested in H-2/H2O and CH4/H2O atmospheres vs. air in the temperature range of 800-1015 degrees C, An area specific....../N-2 = 33/3/64. No carbon deposition was found on CG4 after cell operation at a steam-to-carbon ratio of 0.3 for 1000 h. Cells sustained several rapid thermal cycles in the temperature interval 200-1000 degrees C and a full redox cycle without degradation. (C) 1999 Elsevier Science B.V. All rights...

  12. Effect of ionic conductivity of zirconia electrolytes on polarization properties of various electrodes in SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masahiro; Uchida, Hiroyuki; Yoshida, Manabu [Yamanashi Univ., Kofu (Japan)

    1996-12-31

    Solid oxide fuel cells (SOFCs) have been intensively investigated because, in principle, their energy conversion efficiency is fairly high. Lowering the operating temperature of SOFCs from 1000{degrees}C to around 800{degrees}C is desirable for reducing serious problems such as physical and chemical degradation of the constructing materials. The object of a series of the studies is to find a clue for achieving higher electrode performances at a low operating temperature than those of the present level. Although the polarization loss at electrodes can be reduced by using mixed-conducting ceria electrolytes, or introducing the mixed-conducting (reduced zirconia or ceria) laver on the conventional zirconia electrolyte surface, no reports are available on the effect of such an ionic conductivity of electrolytes on electrode polarizations. High ionic conductivity of the electrolyte, of course, reduces the ohmic loss. However, we have found that the IR-free polarization of a platinum anode attached to zirconia electrolytes is greatly influenced by the ionic conductivity, {sigma}{sub ion}, of the electrolytes used. The higher the {sigma}{sub ion}, the higher the exchange current density, j{sub 0}, for the Pt anode in H{sub 2} at 800 {approximately} 1000{degrees}C. It was indicated that the H{sub 2} oxidation reaction rate was controlled by the supply rate of oxide ions through the Pt/zirconia interface which is proportional to the {sigma}{sub ion}. Recently, we have proposed a new concept of the catalyzed-reaction layers which realizes both high-performances of anodes and cathodes for medium-temperature operating SOFCs. We present the interesting dependence of the polarization properties of various electrodes (the SDC anodes with and without Ru microcatalysts, Pt cathode, La(Sr)MnO{sub 3} cathodes with and without Pt microcatalysts) on the {sigma}{sub ion} of various zirconia electrolytes at 800 {approximately} 1000{degrees}C.

  13. Thermodynamic analysis of SOFC (solid oxide fuel cell) - Stirling hybrid plants using alternative fuels

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2013-01-01

    A novel hybrid power system (∼10 kW) for an average family home is proposed. The system investigated contains a solid oxide fuel cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle are fed to a bottoming Stirling engine, at which additional power is generated...... to that of a stand-alone Stirling engine or SOFC plant. For the combined SOFC and Stirling configuration, the overall power production was increased by approximately 10% compared to that of a stand-alone SOFC plant. System efficiencies of approximately 60% are achieved, which is remarkable for such small plant sizes...

  14. Microstructural characterization of Ni/YSZ based SOFC anodes after cyclic reduction and oxidation using electron microscopy

    International Nuclear Information System (INIS)

    Waldbillig, D.; He, A.; Ivey, D.

    2003-01-01

    The effect of redox cycling on the microstructure, of an SOFC anode, was studied using two approaches. Bulk samples were redox cycled and then examined in the SEM. In addition, electron transparent samples were prepared, redox cycled, and then examined in the TEM. Significant microstructural changes were observed. The anode in the as received condition consists of NiO particles several microns in size, YSZ grains about one micron in size and intergranular porosity. After the first reduction, the overall Ni grain size remains the same as the consumed NiO and epitaxial growth of Ni crystals on NiO grains is observed. The amount of intergranular porosity increases and very fine (50 nm) intragranular pores are formed throughout the Ni grains. This increase in the amount of porosity is expected due to the large volume change that occurs upon reduction. When samples are reoxidized the NiO particles in the SEM images appear spongy with much smaller pores than the as received, oxidized samples. The reoxidized anode consists of fine (<100 nm), randomly oriented grains of NiO. The grain refinement that occurs upon reoxidation is likely due to the large number of intragranular pores that occur upon reduction, which serve as nucleation sites. Rereduced samples were also very fine grained (<200 nm) and contained significant amounts of small intergranular porosity. The YSZ grains were unaffected by the redox cycles. (author)

  15. Scaling up aqueous processing of A-site deficient strontium titanate for SOFC anode supports

    DEFF Research Database (Denmark)

    Verbraeken, Maarten C.; Sudireddy, Bhaskar Reddy; Vasechko, Viacheslav

    2018-01-01

    All ceramic anode supported half cells of technically relevant scale were fabricated in this study, using a novel strontium titanate anode material. The use of this material would be highly advantageous in solid oxide fuel cells due to its redox tolerance and resistance to coking and sulphur...... poisoning. Successful fabrication was possible through aqueous tape casting of both anode support and electrolyte layers and subsequent lamination. Screen printing of electrolyte layers onto green anode tapes was also attempted but resulted in cracked electrolyte layers upon firing. Microstructural...

  16. Advances in catalysts for internal reforming in high temperature fuel cells

    Science.gov (United States)

    Dicks, A. L.

    Catalytic steam reforming of natural gas is an attractive method of producing the hydrogen required by the present generation of fuel cells. The molten carbonate (MCFC) and solid oxide (SOFC) fuel cells operate at high enough temperatures for the endothermic steam reforming reaction to be carried out within the stack. For the MCFC, the conventional anodes have insufficient activity to catalyse the steam reforming of natural gas. For these cells, internal reforming can be achieved only with the addition of a separate catalyst, preferably located in close proximity to the anode. However, in the so-called `Direct Internal Reforming' configuration, attack from alkali in the MCFC may severely limit catalyst lifetime. In the case of the state-of-the-art SOFC, natural gas can be reformed directly on the nickel cermet anode. However, in the SOFC, temperature variations in the cell caused by the reforming reaction may limit the amount of internal reforming that can be allowed in practice. In addition, some external pre-reforming may be desirable to remove high molecular weight hydrocarbons from the fuel gas, which would otherwise crack to produce elemental carbon. Degradation of the SOFC anode may also be a problem when internal reforming is carried out. This has prompted several research groups to investigate the use of alternative anode materials.

  17. Quality Assurance of Solid Oxide Fuel Cell (SOFC) and Electrolyser (SOEC) Stacks

    DEFF Research Database (Denmark)

    Lang, Michael; Auer, Corinna; Couturier, Karine

    2017-01-01

    In the EU-funded project “Solid oxide cell and stack testing and quality assurance” (SOCTESQA) standardized and industry wide test modules and programs for high temperature solid oxide cells and stacks are being developed. These test procedures can be applied for the fuel cell (SOFC......), the electrolysis (SOEC) and in the combined SOFC/SOEC mode. In order to optimize the test modules the project partners have tested identical SOC stacks with the same test programs in several testing campaigns. Altogether 10 pre-normative test modules were developed: Start-up, current-voltage characteristics...

  18. Effect of Humidity in Air on Performance and Long-Term Durability of SOFCs

    DEFF Research Database (Denmark)

    Hagen, Anke; Chen, Ming; Neufeld, Kai

    2009-01-01

    Anode supported SOFCs based on Ni-YSZ anodes, YSZ electrolytes, and LSM-YSZ cathodes were studied with respect to durability in humid air (~4%) over typically 1500 hours. Operating temperature and current density were varied between 750 and 850 oC and 0.25-0.75 A/cm2, respectively. It was found...... that the introduction of humidity affected the cell voltage under polarization of the cell and that this effect was (at least partly) reversible upon switching off the humidity, probably related to a segregation of impurities towards the three phase boundary in the presence of humidity. Generally, the studied cells...... were successfully operated in humid air under technologically relevant conditions. Improvements at the cathode/electrolyte interface made it possible to obtain highly stable cells, which can be operated under high current density and at 750 oC in humid air - conditions that are known to cause...

  19. Compositional control of continuously graded anode functional layer

    Science.gov (United States)

    McCoppin, J.; Barney, I.; Mukhopadhyay, S.; Miller, R.; Reitz, T.; Young, D.

    2012-10-01

    In this work, solid oxide fuel cells (SOFC's) are fabricated with linear-compositionally graded anode functional layers (CGAFL) using a computer-controlled compound aerosol deposition (CCAD) system. Cells with different CGAFL thicknesses (30 um and 50 um) are prepared with a continuous compositionally graded interface deposited between the electrolyte and anode support current collecting regions. The compositional profile was characterized using energy dispersive X-ray spectroscopic mapping. An analytical model of the compound aerosol deposition was developed. The model predicted compositional profiles for both samples that closely matched the measured profiles, suggesting that aerosol-based deposition methods are capable of creating functional gradation on length scales suitable for solid oxide fuel cell structures. The electrochemical performances of the two cells are analyzed using electrochemical impedance spectroscopy (EIS).

  20. A novel design of anode-supported solid oxide fuel cells with Y{sub 2}O{sub 3}-doped Bi{sub 2}O{sub 3}, LaGaO{sub 3} and La-doped CeO{sub 2} trilayer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Weimin [School of Chemistry and Engineering, South China University of Technology, The Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, Guangzhou 510640 (China); Department of Biological and Chemical Engineering, Guangxi University of Technology, Liuzhou 545006 (China); Liu, Jiang [School of Chemistry and Engineering, South China University of Technology, The Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, Guangzhou 510640 (China)

    2010-12-15

    Anode-supported solid oxide fuel cells (SOFCs) with a trilayered yttria-doped bismuth oxide (YDB), strontium- and magnesium-doped lanthanum gallate (LSGM) and lanthanum-doped ceria (LDC) composite electrolyte film are developed. The cell with a YDB (18 {mu}m)/LSGM (19 {mu}m)/LDC (13 {mu}m) composite electrolyte film (designated as cell-A) shows the open-circuit voltages (OCVs) slightly higher than that of a cell with an LSGM (31 {mu}m)/LDC (17 {mu}m) electrolyte film (designated as cell-B) in the operating temperature range of 500-700 C. The cell-A using Ag-YDB composition as cathode exhibits lower polarization resistance and ohmic resistance than those of a cell-B at 700 C. The results show that the introduction of YDB to an anode-supported SOFC with a LSGM/LDC composite electrolyte film can effectively block electronic transport through the cell and thus increased the OCVs, and can help the cell to achieve higher power output. (author)

  1. Palliative effects of H2 on SOFCs operating with carbon containing fuels

    Science.gov (United States)

    Reeping, Kyle W.; Bohn, Jessie M.; Walker, Robert A.

    2017-12-01

    Chlorine can accelerate degradation of solid oxide fuel cell (SOFC) Ni-based anodes operating on carbon containing fuels through several different mechanisms. However, supplementing the fuel with a small percentage of excess molecular hydrogen effectively masks the degradation to the catalytic activity of the Ni and carbon fuel cracking reaction reactions. Experiments described in this work explore the chemistry behind the "palliative" effect of hydrogen on SOFCs operating with chlorine-contaminated, carbon-containing fuels using a suite of independent, complementary techniques. Operando Raman spectroscopy is used to monitor carbon accumulation and, by inference, Ni catalytic activity while electrochemical techniques including electrochemical impedance spectroscopy and voltammetry are used to monitor overall cell performance. Briefly, hydrogen not only completely hides degradation observed with chlorine-contaminated carbon-containing fuels, but also actively removes adsorbed chlorine from the surface of the Ni, allowing for the methane cracking reaction to continue, albeit at a slower rate. When hydrogen is removed from the fuel stream the cell fails immediately due to chlorine occupation of methane/biogas reaction sites.

  2. Characterization of Ni-YSZ anodes for solid oxide fuel cells fabricated by solution precursor plasma spraying with axial feedstock injection

    Science.gov (United States)

    Metcalfe, Craig; Lay-Grindler, Elisa; Kesler, Olivera

    2014-02-01

    Nickel and yttria-stabilized zirconia (YSZ) anodes were fabricated by solution precursor plasma spraying (SPPS) and incorporated into metal-supported solid oxide fuel cells (SOFC). A power density of 0.45 W cm-2 at 0.7 V and a peak power density of 0.52 W cm-2 at 750 °C in humidified H2 was obtained, which are the first performance results reported for an SOFC having an anode fabricated by SPPS. The effects of solution composition, plasma gas composition, and stand-off distance on the composition of the deposited Ni-YSZ coatings by SPPS were evaluated. It was found that the addition of citric acid to the aqueous solution delayed re-solidification of NiO particles, improving the deposition efficiency and coating adhesion. The composition of the deposited coatings was found to vary with torch power. Increasing torch power led to coatings with decreasing Ni content, as a result of Ni vaporizing in-flight at stand-off distances less than 60 mm from the torch nozzle exit.

  3. Sulfur Poisoning of SOFC Anodes: Effect of Overpotential on Long-Term Degradation

    DEFF Research Database (Denmark)

    Hauch, Anne; Hagen, Anke; Hjelm, Johan

    2014-01-01

    characterized during long-term galvanostatic operation in internal reforming gas mixture (CH4/H2O/H2:30/60/10), with 2 ppm H2S exposure to the anode for 500 hours at 850◦C, at different current densities. This work focus on the long-term effect of H2S exposure over a few hundreds of hours; and describes...... and correlates the observed evolution of anode performance, over hundreds of hours, with sulfur exposure at low cell overpotential (low current density) and at high overpotential (high current density) with and without H2S exposure. For tests at low overpotential with H2S exposure only a reversible loss...... in performance was observed and post-mortem SEM analysis showed an intact Ni/YSZ anode microstructure. For tests at high cell overpotential the H2S exposure caused both a reversible loss in performance and an irreversible long-term degradation. Post-mortem SEM analysis of the Ni/YSZ anode from this tests showed...

  4. Durability of solid oxide fuel cells using sulfur containing fuels

    DEFF Research Database (Denmark)

    Hagen, Anke; Rasmussen, Jens Foldager Bregnballe; Thydén, Karl Tor Sune

    2011-01-01

    The usability of hydrogen and also carbon containing fuels is one of the important advantages of solid oxide fuel cells (SOFCs), which opens the possibility to use fuels derived from conventional sources such as natural gas and from renewable sources such as biogas. Impurities like sulfur compounds...... are critical in this respect. State-of-the-art Ni/YSZ SOFC anodes suffer from being rather sensitive towards sulfur impurities. In the current study, anode supported SOFCs with Ni/YSZ or Ni/ScYSZ anodes were exposed to H2S in the ppm range both for short periods of 24h and for a few hundred hours. In a fuel...

  5. Advanced anodes for high-temperature fuel cells

    DEFF Research Database (Denmark)

    Atkinson, A.; Barnett, S.; Gorte, R.J.

    2004-01-01

    Fuel cells will undoubtedly find widespread use in this new millennium in the conversion of chemical to electrical energy, as they offer very high efficiencies and have unique scalability in electricity-generation applications. The solid-oxide fuel cell (SOFC) is one of the most exciting...... of these energy technologies; it is an all-ceramic device that operates at temperatures in the range 500-1,000degreesC. The SOFC offers certain advantages over lower temperature fuel cells, notably its ability to use carbon monoxide as a fuel rather than being poisoned by it, and the availability of high......-grade exhaust heat for combined heat and power, or combined cycle gas-turbine applications. Although cost is clearly the most important barrier to widespread SOFC implementation, perhaps the most important technical barriers currently being addressed relate to the electrodes, particularly the fuel electrode...

  6. Preliminary Electrochemical Characterization of Anode Supported Solid Oxide Cell (AS-SOC) Produced in the Institute of Power Engineering Operated in Electrolysis Mode (SOEC)

    Science.gov (United States)

    Kupecki, Jakub; Motyliński, Konrad; Skrzypkiewicz, Marek; Wierzbicki, Michał; Naumovich, Yevgeniy

    2017-12-01

    The article discusses the operation of solid oxide electrochemical cells (SOC) developed in the Institute of Power Engineering as prospective key components of power-to-gas systems. The fundamentals of the solid oxide cells operated as fuel cells (SOFC - solid oxide fuel cells) and electrolysers (SOEC - solid oxide fuel cells) are given. The experimental technique used for electrochemical characterization of cells is presented. The results obtained for planar cell with anodic support are given and discussed. Based on the results, the applicability of the cells in power-to-gas systems (P2G) is evaluated.

  7. Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin

    International Nuclear Information System (INIS)

    Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O.

    2016-01-01

    Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca_3Co_4O_9, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

  8. Reviews on Solid Oxide Fuel Cell Technology

    Directory of Open Access Journals (Sweden)

    Apinan Soottitantawat

    2009-02-01

    Full Text Available Solid Oxide Fuel Cell (SOFC is one type of high temperature fuel cell that appears to be one of the most promising technology to provide the efficient and clean energy production for wide range of applications (from small units to large scale power plants. This paper reviews the current status and related researches on SOFC technologies. In details, the research trend for the development of SOFC components(i.e. anode, electrolyte, cathode, and interconnect are presented. Later, the current important designs of SOFC (i.e. Seal-less Tubular Design, Segmented Cell in Series Design, Monolithic Design and Flat Plate Design are exampled. In addition, the possible operations of SOFC (i.e. external reforming, indirect internal reforming, and direct internal reforming are discussed. Lastly, the research studies on applications of SOFCs with co-generation (i.e. SOFC with Combined Heat and Power (SOFC-CHP, SOFC with Gas Turbine (SOFC-GT and SOFC with chemical production are given.

  9. Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin; Preparacao de materiais catodicos para celulas a combustivel de oxido solido (SOFC) atraves do uso de gelatina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O., E-mail: rinaldo_mendesa@hotmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

    2016-07-01

    Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca{sub 3}Co{sub 4}O{sub 9}, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

  10. Thermodynamic and thermoeconomic analysis of a system with biomass gasification, solid oxide fuel cell (SOFC) and Stirling engine

    International Nuclear Information System (INIS)

    Rokni, Masoud

    2014-01-01

    Thermodynamic and thermoeconomic investigations of a small-scale integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120 kW e have been performed. Woodchips are used as gasification feedstock to produce syngas, which is then utilized to feed the anode side of the SOFC stacks. A thermal efficiency of 0.424 LHV (lower heating value) for the plant is found to use 89.4 kg/h of feedstock to produce the above mentioned electricity. Thermoeconomic analysis shows that the production price of electricity is 0.1204 $/kWh. Furthermore, hot water is considered as a by-product, and the cost of hot water is found to be 0.0214 $/kWh. When compared to other renewable systems of similar scales, this result shows that if both SOFC and Stirling engine technology enter the commercialization phase, then they can deliver electricity at a cost that is competitive with the corresponding renewable systems of the same size. - Highlights: • A 120 kW e integrated gasification SOFC–Stirling CHP is presented. • Effect of important parameters on plant characteristic and economy are studied. • A modest thermal efficiency of 0.41 is found after thermoeconomic optimization. • Reducing stack numbers cuts cost of electricity at expense of thermal efficiency. • The plant cost is estimated to be about 3433 $/kW when disposal costs are neglected

  11. Synthesis and characterization of scandia ceria stabilized zirconia powders prepared by polymeric precursor method for integration into anode-supported solid oxide fuel cells

    Science.gov (United States)

    Tu, Hengyong; Liu, Xin; Yu, Qingchun

    2011-03-01

    Scandia ceria stabilized zirconia (10Sc1CeSZ) powders are synthesized by polymeric precursor method for use as the electrolyte of anode-supported solid oxide fuel cell (SOFC). The synthesized powders are characterized in terms of crystalline structure, particle shape and size distribution by X-ray diffraction (XRD), transmission electron microscopy (TEM) and photon correlation spectroscopy (PCS). 10Sc1CeSZ electrolyte films are deposited on green anode substrate by screen-printing method. Effects of 10Sc1CeSZ powder characteristics on sintered films are investigated regarding the integration process for application as the electrolytes in anode-supported SOFCs. It is found that the 10Sc1CeSZ films made from nano-sized powders with average size of 655 nm are very porous with many open pores. In comparison, the 10Sc1CeSZ films made from micron-sized powders with average size of 2.5 μm, which are obtained by calcination of nano-sized powders at higher temperatures, are much denser with a few closed pinholes. The cell performances are 911 mW cm-2 at the current density of 1.25 A cm-2 and 800 °C by application of Ce0.8Gd0.2O2 (CGO) barrier layer and La0.6Sr0.4CoO3 (LSC) cathode.

  12. Model-supported interpretation of the electrochemical characteristics of solid oxide fuel cells with Ni/YSZ cermet anodes; Modellgestuetzte Interpretation der elektrochemischen Charakteristik von Festoxid-Brennstoffzellen mit Ni/YSZ-Cermetanoden

    Energy Technology Data Exchange (ETDEWEB)

    Gewies, Stefan

    2009-01-29

    This work presents the development, validation and application of a multiscale model for the detailed description of a solid oxide fuel cell (SOFC) with a Ni/YSZ (nickel/yttria-stabilized zirconia) cermet anode. The aim of the study is the identification of the physico-chemical loss processes, as seen in impedance spectra and polarization curves. The model consists of an elementary kinetic description of the electrochemistry including the development of an electrical double layer at the electrode/electrolyte interface of the cermet anode, a homogenized description of charge and gas-phase transport in the electrodes as well as a macroscopic description of convective and diffusive mass transport in the gas phase above the electrodes. For the rst time this study allows for a complete description of the impedance spectra of a diffusively fuel-supplied cermet anode. By comparing simulations with experiments on symmetrical cells (University of Karlsruhe) three dominant loss processes could be identified. The model was extended to account for the description of segmented SOFCs. In correspondence with experimental data (German Aerospace Center) the simulations show strong gradients in current densities and gas concentrations. (orig.)

  13. Modeling the integration of thermoelectrics in anode exhaust combustors for waste heat recovery in fuel cell systems

    Science.gov (United States)

    Maghdouri Moghaddam, Anita

    Recently developed small-scale hydrocarbon-fueled fuel cell systems for portable power under 1 kW have overall system efficiencies typically no higher than 30-35%. This study explores the possibility of using of thermoelectric waste heat recovery in anode exhaust combustors to improve the fuel cell system efficiencies by as much as 4-5% points and further to reduce required battery power during system start-up. Two models were used to explore this. The first model simulated an integrated SOFC system with a simplified catalytic combustor model with TEs integrated between the combustor and air preheating channels for waste heat recovery. This model provided the basis for assessing how much additional power can achieve during SOFC operation as a function of fuel cell operating conditions. Results for the SOFC system indicate that while the TEs may recover as much as 4% of the total fuel energy into the system, their benefit is reduced in part because they reduce the waste heat transferred back to the incoming air stream and thereby lower the SOFC operating temperatures and operating efficiencies. A second model transient model of a TE-integrated catalytic combustor explored the performance of the TEs during transient start-up of the combustor. This model incorporated more detailed catalytic combustion chemistry and enhanced cooling air fin heat transfer to show the dynamic heating of the integrated combustor. This detailed model provided a basis for exploring combustor designs and showed the importance of adequate reactant preheating when burning exhaust from a reformer during start-up for the TEs to produce significant power to reduce the size of system batteries for start-up.

  14. Manufacture of SOFC electrodes by wet powder spraying

    Energy Technology Data Exchange (ETDEWEB)

    Wilkenhoener, R.; Mallener, W.; Buchkremer, H.P. [Forschungszentrum Juelich GmbH (Germany)] [and others

    1996-12-31

    The reproducible and commercial manufacturing of electrodes with enhanced electrochemical performance is of central importance for a successful technical realization of Solid Oxide Fuel Cell (SOFC) systems. The route of electrode fabrication for the SOFC by Wet Powder Spraying (WPS) is presented. Stabilized suspensions of the powder materials for the electrodes were sprayed onto a substrate by employing a spray gun. After drying of the layers, binder removal and sintering are performed in one step. The major advantage of this process is its applicability for a large variety of materials and its flexibility with regard to layer shape and thickness. Above all, flat or curved substrates of any size can be coated, thus opening up the possibility of {open_quotes}up-scaling{close_quotes} SOFC technology. Electrodes with an enhanced electrochemical performance were developed by gradually optimizing the different process steps. For example an optimized SOFC cathode of the composition La{sub 0.65}Sr{sub 0.3}MnO{sub 3} with 40% 8YSZ showed a mean overpotential of about -50 mV at a current density of -0.8 A/cm{sup 2}, with a standard deviation amounting to 16 mV (950{degrees}C, air). Such optimized electrodes can be manufactured with a high degree of reproducibility, as a result of employing a computer-controlled X-Y system for moving the spray gun. Several hundred sintered composites, comprising the substrate anode and the electrolyte, of 100x 100 mm{sup 2} were coated with the cathode by WPS and used for stack integration. The largest manufactured electrodes were 240x240 mm{sup 2}, and data concerning their thickness homogeneity and electrochemical performance are given.

  15. Development of planar SOE/SOFC reversible cell

    International Nuclear Information System (INIS)

    Kusunoki, A.; Matsubara, H.; Kikuoka, Y.; Yanagi, C.; Kugimiya, K.; Yoshino, M.; Tokura, M.; Watanabe, K.; Ueda, S.; Sumi, M.; Miyamoto, H.; Tokunaga, S.

    1993-01-01

    A new energy storage system using SOE/SOFC (solid oxide electrolysis-solid oxide fuel cells) reversible cells is presented, where a unit cell works as a fuel cell during a period of high electric power demand and alternately works as an electrolysis cell during a period of low power demand. A planar cell configuration is used which allows for a compact and low cost energy storage and load leveling system for power stations. Tests were performed to verify the reversibility of the planar cell, at 1000 deg C, with YSZ (Yttria stabilized zirconia) as the solid electrolyte, to improve the cell performance by reducing the overvoltage in electrolysis, and to obtain fundamental characteristics of a reversible cell. 3 figs

  16. On the Predictions of Carbon Deposition on the Nickel Anode of a SOFC and Its Impact on Open-Circuit Conditions

    KAUST Repository

    Lee, W. Y.

    2012-12-04

    Previous thermodynamic analyses of carbon formation in SOFCs assumed that graphite could be used to represent the properties of carbon formed in the anode. It is generally observed, however, that catalytically grown carbon nanofibers (CNF) are more likely to form in the SOFC anode with nickel catalysts. The energetic and entropic properties of CNF are different from those of graphite.We compare equilibrium results based on thermochemical properties for graphite, to new results based on a previously reported value of an empirically determined Gibbs free energy for carbon fibers grown on a nickel support (with fitted values of H°CNF = 54.46 kJ/mol and S°CNF = 68.90 J/mol/K for a nickel crystal size of 5.4 nm). There is little difference in predictions of carbon formation under open-circuit conditions between the two carbon types for methane mixtures, with graphite predicted to form at lower temperatures than CNF. There is a much bigger difference in predictions for methanol mixtures, especially at low steam-carbon ratios. The differences for propane are even more pronounced, and the improved predictions assuming CNF are in closer agreement with past observations.We show a strong dependence of CNF formation and "coking threshold" on nickel crystallite size, supporting previous reports that the nickel particle size is a dominating parameter for controlling filament growth. If both carbon types are included in the calculations, only the thermodynamically favored form (i.e., the type having the lowest formation energy) exists. Predicted Nernst potentials are more-or-less independent of the carbon type and in agreement with measured open-circuit voltages. © 2012 The Electrochemical Society.

  17. Production and Reliability Oriented SOFC Cell and Stack Design

    DEFF Research Database (Denmark)

    Hauth, Martin; Lawlor, Vincent; Cartellieri, Peter

    2017-01-01

    The paper presents an innovative development methodology for a production and reliability oriented SOFC cell and stack design aiming at improving the stacks robustness, manufacturability, efficiency and cost. Multi-physics models allowed a probabilistic approach to consider statistical variations...... in production, material and operating parameters for the optimization phase. A methodology for 3D description of spatial distribution of material properties based on a random field models was developed and validated by experiments. Homogenized material models on multiple levels of the SOFC stack were...... and output parameters and to perform a sensitivity analysis were developed and implemented. The capabilities of the methodology is illustrated on two practical cases....

  18. Development of Residential SOFC Cogeneration System

    International Nuclear Information System (INIS)

    Ono, Takashi; Miyachi, Itaru; Suzuki, Minoru; Higaki, Katsuki

    2011-01-01

    Since 2001 Kyocera has been developing 1kW class Solid Oxide Fuel Cell (SOFC) for power generation system. We have developed a cell, stack, module and system. Since 2004, Kyocera and Osaka Gas Co., Ltd. have been developed SOFC residential co-generation system. From 2007, we took part in the 'Demonstrative Research on Solid Oxide Fuel Cells' Project conducted by New Energy Foundation (NEF). Total 57 units of 0.7kW class SOFC cogeneration systems had been installed at residential houses. In spite of residential small power demand, the actual electric efficiency was about 40%(netAC,LHV), and high CO2 reduction performance was achieved by these systems. Hereafter, new joint development, Osaka Gas, Toyota Motors, Kyocera and Aisin Seiki, aims early commercialization of residential SOFC CHP system.

  19. Development of Residential SOFC Cogeneration System

    Science.gov (United States)

    Ono, Takashi; Miyachi, Itaru; Suzuki, Minoru; Higaki, Katsuki

    2011-06-01

    Since 2001 Kyocera has been developing 1kW class Solid Oxide Fuel Cell (SOFC) for power generation system. We have developed a cell, stack, module and system. Since 2004, Kyocera and Osaka Gas Co., Ltd. have been developed SOFC residential co-generation system. From 2007, we took part in the "Demonstrative Research on Solid Oxide Fuel Cells" Project conducted by New Energy Foundation (NEF). Total 57 units of 0.7kW class SOFC cogeneration systems had been installed at residential houses. In spite of residential small power demand, the actual electric efficiency was about 40%(netAC,LHV), and high CO2 reduction performance was achieved by these systems. Hereafter, new joint development, Osaka Gas, Toyota Motors, Kyocera and Aisin Seiki, aims early commercialization of residential SOFC CHP system.

  20. Chemical compatibility and properties of suspension plasma-sprayed SrTiO3-based anodes for intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Zhang, Shan-Lin; Li, Cheng-Xin; Li, Chang-Jiu

    2014-10-01

    La-doped strontium titanate (LST) is a promising, redox-stable perovskite material for direct hydrocarbon oxidation anodes in intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this study, nano-sized LST and Sm-doped ceria (SDC) powders are produced by the sol-gel and glycine-nitrate processes, respectively. The chemical compatibility between LST and electrolyte materials is studied. A LST-SDC composite anode is prepared by suspension plasma spraying (SPS). The effects of annealing conditions on the phase structure, microstructure, and chemical stability of the LST-SDC composite anode are investigated. The results indicate that the suspension plasma-sprayed LST-SDC anode has the same phase structure as the original powders. LST exhibits a good chemical compatibility with SDC and Mg/Sr-doped lanthanum gallate (LSGM). The anode has a porosity of ∼40% with a finely porous structure that provides high gas permeability and a long three-phase boundary for the anode reaction. Single cells assembled with the LST-SDC anode, La0.8Sr0.2Ga0.8Mg0.2O3 electrolyte, and La0.8Sr0.2CoO3-SDC cathode show a good performance at 650-800 °C. The annealing reduces the impedances due to the enhancement in the bonding between the particles in the anode and interface of anode and LSGM electrolyte, thus improving the output performance of the cell.

  1. Direct comparison between X-ray nanotomography and scanning electron microscopy for the microstructure characterization of a solid oxide fuel cell anode

    International Nuclear Information System (INIS)

    Quey, R.; Suhonen, H.; Laurencin, J.; Cloetens, P.; Bleuet, P.

    2013-01-01

    X-ray computed nanotomography (nano-CT) and scanning electron microscopy (SEM) have been applied to characterize the microstructure of a Solid Oxide Fuel Cell (SOFC) anode. A direct comparison between the results of both methods is conducted on the same region of the microstructure to assess the spatial resolution of the nano-CT microstructure, SEM being taken as a reference. A registration procedure is proposed to find out the position of the SEM image within the nano-CT volume. It involves a second SEM observation, which is taken along an orthogonal direction and gives an estimate reference SEM image position, which is then refined by an automated optimization procedure. This enables an unbiased comparison between the cell porosity morphologies provided by both methods. In the present experiment, nano-CT is shown to underestimate the number of pores smaller than 1 μm and overestimate the size of the pores larger than 1.5 μm. - Highlights: ► X-ray computed nanotomography (nano-CT) and SEM are used to characterize an SOFC anode. ► A methodology is proposed to compare the nano-CT and SEM data on the same region. ► The spatial resolution of the nano-CT data is assessed from that comparison

  2. Development of cofired type planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Taira, Hiroaki; Sakamoto, Sadaaki; Zhou, Hua-Bing [Murata Manufacturing Co., Ltd., Shiga (Japan)] [and others

    1996-12-31

    We have developed fabrication process for planar SOFC fabricated with cofired anode/electrolyte/cathode multilayers and interconnects. By cofiring technique for the multilayers, we expect to reduce the thickness of the electrolyte layers, resulting in decrease of innerimpedance, and achieve low production cost. On the other hand, the cofiring technique requires that the sintering temperature, the shrinkage profiles and the thermal expansion characteristics of all component materials should be compatible with the other. It is, therefore, difficult to cofire the multilayers with large area. Using the multilayers with surface area of 150cm{sup 2}, we fabricated the multiple cell stacks. The maximum power of 5x4 multiple cell stack (5 planes of cells in series, 4 cells in parallel in each planes 484cm{sup 2} effective electrode area of each cell planes) was 601W (0.25Wcm{sup -2}, Uf=40%). However, the terminal voltage of the multiple cell stack decreased by the cause of cell cracking, gas leakage and degradation of cofired multilayers. This paper presents the improvements of cofired multilayers, and the performance of multiple cell stacks with the improved multilayers.

  3. Properties and Performance of SOFCs Produced on a Pre-Pilot Plant Scale

    DEFF Research Database (Denmark)

    Hagen, Anke; Menon, Mohan; Barfod, Rasmus

    2006-01-01

    specific cell resistance at 850 °C was found to be 0.24 Ω cm2 with a standard deviation of 0.05 Ω cm2. The variation in performance between the cells can be largely attributed to variations in the cathode performance. Experimental evidence will be presented on full 4 × 4 cm2 cells, symmetric cells with two......In the present paper, anode supported solid oxide fuel cells (SOFCs), produced on a pre-pilot plant scale in ten batches of ∼100 cells, are characterised with respect to performance. The main purpose was to evaluate the reproducibility of the scaled-up process. Based on 20 tests, the average area...

  4. Performance of strontium- and magnesium-doped lanthanum gallate electrolyte with lanthanum-doped ceria as a buffer layer for IT-SOFCs

    Science.gov (United States)

    Lee, Dokyol; Han, Ju-Hyeong; Kim, Eun-Gu; Song, Rak-Hyun; Shin, Dong-Ryul

    La 0.8Sr 0.2Ga 0.8Mg 0.2O 2.8 (LSGM8080) powder, showing the highest electrical conductivity among LSGMs of various compositions, is synthesized using the glycine nitrate process (GNP) and used as the electrolyte for an intermediate-temperature solid oxide fuel cell (IT-SOFC). The LDC (Ce 0.55La 0.45O 1.775) powder is synthesized by a solid-state reaction and employed as the material for a buffer layer to prevent the reaction between the anode and electrolyte materials. The LDC also serves as the skeleton material for the anode. An anode-supported single cell with an active area of 1 cm 2 is constructed for performance evaluation. A single-cell test is performed at 750 and 800 °C. The maximum power density of the cell 459 and 664 mW cm -2 at 750 and 800 °C, respectively.

  5. Solid Oxide Fuel Cell Based Upon Colloidal Deposition of Thin Films for Lower Temperature Operation (Preprint)

    National Research Council Canada - National Science Library

    Reitz, T. L; Xiao, H

    2006-01-01

    In order to reduce the operating temperature of solid oxide fuel cells (SOFCs), anode-supported cells incorporating thin film electrolytes in conjunction with anode/electrolyte and cathode/electrolyte interlayers were studied...

  6. Power generation efficiency of an SOFC-PEFC combined system with time shift utilization of SOFC exhaust heat

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Shin' ya [Power Engineering Lab., Department of Electrical and Electronic Engineering, Kitami Institute of Technology, 165 Kouen-cho, Kitami, Hokkaido 0908507 (Japan)

    2010-01-15

    A microgrid, with little environmental impact, is developed by introducing a combined SOFC (solid oxide fuel cell) and PEFC (proton exchange membrane fuel cell) system. Although the SOFC requires a higher operation temperature compared to the PEFC, the power generation efficiency of the SOFC is higher. However, if high temperature exhaust heat may be used effectively, a system with higher total power generation efficiency can be built. Therefore, this paper investigates the operation of a SOFC-PEFC combined system, with time shift operation of reformed gas, into a microgrid with 30 houses in Sapporo, Japan. The SOFC is designed to correspond to base load operation, and the exhaust heat of the SOFC is used for production of reformed gas. This reformed gas is used for the production of electricity for the PEFC, corresponding to fluctuation load of the next day. Accordingly, the reformed gas is used with a time shift operation. In this paper, the relation between operation method, power generation efficiency, and amount of heat storage of the SOFC-PEFC combined system to the difference in power load pattern was investigated. The average power generation efficiency of the system can be maintained at nearly 48% on a representative day in February (winter season) and August (summer season). (author)

  7. Methane steam reforming kinetics over Ni-YSZ anode materials for Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Mogensen, David

    of internal reforming has to be carefully controlled. The objective of this thesis is to make such a careful control possible by examining the rate of internal steam reforming in SOFCs. The catalytic steam reforming activity of Ni-YSZ anode material was tested both in a packed bed reactor to determine...

  8. Challenge for lowering concentration polarization in solid oxide fuel cells

    Science.gov (United States)

    Shimada, Hiroyuki; Suzuki, Toshio; Yamaguchi, Toshiaki; Sumi, Hirofumi; Hamamoto, Koichi; Fujishiro, Yoshinobu

    2016-01-01

    In the scope of electrochemical phenomena, concentration polarization at electrodes is theoretically inevitable, and lowering the concentration overpotential to improve the performance of electrochemical cells has been a continuing challenge. Electrodes with highly controlled microstructure, i.e., high porosity and uniform large pores are therefore essential to achieve high performance electrochemical cells. In this study, state-of-the-art technology for controlling the microstructure of electrodes has been developed for realizing high performance support electrodes of solid oxide fuel cells (SOFCs). The key is controlling the porosity and pore size distribution to improve gas diffusion, while maintaining the integrity of the electrolyte and the structural strength of actual sized electrode supports needed for the target application. Planar anode-supported SOFCs developed in this study realize 5 μm thick dense electrolyte (yttria-stabilized zirconia: YSZ) and the anode substrate (Ni-YSZ) of 53.6 vol.% porosity with a large median pore diameter of 0.911 μm. Electrochemical measurements reveal that the performance of the anode-supported SOFCs improves with increasing anode porosity. This Ni-YSZ anode minimizes the concentration polarization, resulting in a maximum power density of 3.09 W cm-2 at 800 °C using humidified hydrogen fuel without any electrode functional layers.

  9. Preparation of functional layers for anode-supported solid oxide fuel cells by the reverse roll coating process

    Science.gov (United States)

    Mücke, R.; Büchler, O.; Bram, M.; Leonide, A.; Ivers-Tiffée, E.; Buchkremer, H. P.

    The roll coating technique represents a novel method for applying functional layers to solid oxide fuel cells (SOFCs). This fast process is already used for mass production in other branches of industry and offers a high degree of automation. It was utilized for coating specially developed anode (NiO + 8YSZ, 8YSZ: 8 mol% yttria-stabilized zirconia) and electrolyte (8YSZ) suspensions on green and pre-sintered tape-cast anode supports (NiO + 8YSZ). The layers formed were co-fired in a single step at 1400 °C for 5 h. As a result, the electrolyte exhibited a thickness of 14-18 μm and sufficient gas tightness. Complete cells with a screen-printed and sintered La 0.65Sr 0.3MnO 3- δ (LSM)/8YSZ cathode yielded a current density of 0.9-1.1 A cm -2 at 800 °C and 0.7 V, which is lower than the performance of non-co-fired slip-cast or screen-printed Jülich standard cells with thinner anode and electrolyte layers. The contribution of the cell components to the total area-specific resistance (ASR) was calculated by analyzing the distribution function of the relaxation times (DRTs) of measured electrochemical impedance spectra (EIS) and indicates the potential improvement in the cell performance achievable by reducing the thickness of the roll-coated layers. The results show that the anode-supported planar half-cells can be fabricated cost-effectively by combining roll coating with subsequent co-firing.

  10. Single-chamber solid oxide fuel cell technology - From its origins to today's state of the art

    Energy Technology Data Exchange (ETDEWEB)

    Khun, M. [Department of Mechanical Engineering, Ecole Polytechnique de Montreal, Montreal, Quebec, H3T 1J4 (Canada); Napporn, T. W. [Equipe Electrocatalyse, Laboratoire de Catalyse en Chimie Organique, UMR CNRS 6503, Universite de Poitiers, Poitiers (France)

    2010-07-01

    In single-chamber solid oxide fuel cells (SC-SOFCs), both anode and cathode are situated in a common gas chamber and are exposed to a mixture of fuel and oxidant. The working principle is based on the difference in catalytic activity of the electrodes for the respective anodic and cathodic reactions. The resulting difference in oxygen partial pressure between the electrodes leads to the generation of an open circuit voltage. Progress in SC-SOFC technology has enabled the generation of power outputs comparable to those of conventional SOFCs. This paper provides a detailed review of the development of SC-SOFC technology. (author)

  11. SOFC-anodes, proof for a finite-lenght type Gerischer impedance?

    NARCIS (Netherlands)

    Boukamp, Bernard A.; Verbraeken, M.; Blank, David H.A.; Holtappels, P.

    2006-01-01

    The impedance of a symmetric cell with Ni/Ti-doped YSZ cermet anodes was measured as function of ambient (PH2, PH2O) and temperature. The impedances showed identical shapes with a minor dispersive contribution in the high frequency region and a dominating dispersion down to 0.01 Hz. The

  12. Performance of strontium- and magnesium-doped lanthanum gallate electrolyte with lanthanum-doped ceria as a buffer layer for IT-SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dokyol; Han, Ju-Hyeong; Kim, Eun-Gu [Department of Materials Science and Engineering, Korea University, 5-1 Anam-dong, Seongbuk-gu, Seoul 136-713 (Korea); Song, Rak-Hyun; Shin, Dong-Ryul [Hydrogen and Fuel Cell Research Department, Korea Institute of Energy Research, 71-2 Jang-dong, Yuseong-gu, Daejeon 305-600 (Korea)

    2008-10-15

    La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2}O{sub 2.8} (LSGM8080) powder, showing the highest electrical conductivity among LSGMs of various compositions, is synthesized using the glycine nitrate process (GNP) and used as the electrolyte for an intermediate-temperature solid oxide fuel cell (IT-SOFC). The LDC (Ce{sub 0.55}La{sub 0.45}O{sub 1.775}) powder is synthesized by a solid-state reaction and employed as the material for a buffer layer to prevent the reaction between the anode and electrolyte materials. The LDC also serves as the skeleton material for the anode. An anode-supported single cell with an active area of 1 cm{sup 2} is constructed for performance evaluation. A single-cell test is performed at 750 and 800 C. The maximum power density of the cell 459 and 664 mW cm{sup -2} at 750 and 800 C, respectively. (author)

  13. Development of layered anode structures supported over Apatite-type Solid Electrolytes

    Directory of Open Access Journals (Sweden)

    Pandis P.

    2016-01-01

    Full Text Available Apatite-type lanthanum silicates (ATLS materials have attracted interest in recent literature as solid electrolytes for SOFCs. The fabrication of an ATLS based fuel cell with the state-of-art electrodes (NiO/YSZ as anode and LSCF or LSM as cathode can show degradation after long operation hours due to Si diffusion mainly towards the anode. In this work, we report a “layer-by-layer anodic electrodes” fabrication by means of spin coating and physical spraying. The overall aim of this work is the successful fabrication of such a layered structure including suitable blocking layers towards the inhibition of Si interdiffusion from the apatite electrolyte to the anode. The results showed that the deposition of 3 layers of LFSO/GDC (3μm, NiO/GDC (4μm and the final NiO/YSZ anode layer provided a stable half-cell, with no solid state reaction occurring among the electrodes and no Si diffusion observed towards the anode after thermal treatment at 800°C for 120h.

  14. Performance of planar single cell lanthanum gallate based solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Maffei, N.; Kuriakose, A.K. [Materials Technology Labs., CANMET, Natural Resources Canada, Ottawa, ON (Canada)

    1998-09-01

    A novel synthesis of high purity, single phase strontium-magnesium doped lanthanum gallate through a nitrate route is described. The prepared powder is formed into planar monolithic elements by uniaxial pressing followed by isostatic pressing and sintering. XRD analysis of the sintered elements reveal no detectable secondary phases. The performance of the electrolyte in solid oxide fuel cells (SOFC) with three different anode/cathode combinations tested at 700 C with respect to the J-V and power density is reported. The data show that the characteristics of this SOFC are strongly dependent on the particular anode/cathode system chosen. (orig.)

  15. Performance of planar single cell lanthanum gallate based solid oxide fuel cells

    Science.gov (United States)

    Maffei, N.; Kuriakose, A. K.

    A novel synthesis of high purity, single phase strontium-magnesium doped lanthanum gallate through a nitrate route is described. The prepared powder is formed into planar monolithic elements by uniaxial pressing followed by isostatic pressing and sintering. XRD analysis of the sintered elements reveal no detectable secondary phases. The performance of the electrolyte in solid oxide fuel cells (SOFC) with three different anode/cathode combinations tested at 700°C with respect to the J- V and power density is reported. The data show that the characteristics of this SOFC are strongly dependent on the particular anode/cathode system chosen.

  16. Life cycle assessment of an SOFC/GT process

    Energy Technology Data Exchange (ETDEWEB)

    Olausson, Pernilla

    1999-06-01

    For the last few years much effort has been put into the research on different kinds of fuel cells, since these are considered to be both an efficient and environment friendly way to convert energy. The fuel cell studied here is the solid oxide fuel cell (SOFC) that works at a high temperature (800-1000 C) and today achieves a stand-alone electric efficiency of approximately 50%. When integrating the SOFC in a gas turbine process (SOFC/GT process) an efficiency of 70-75% can be reached. The SOFC and the SOFC/GT process are considered to be environment friendly regarding the discharges during operation. Especially formation of nitrogen oxides (NO{sub x}) is low since the SOFC temperatures are low compared to NO{sub x} formation temperatures. To study the whole environmental impact of the SOFC/GT process a life cycle assessment (LCA) is carried out to find the `hot spots` in the process` life cycle. Since the SOFC/GT process is under development today the collected data are mainly from literature and articles based on laboratory results. When performing the LCA only the SOFC-module and the gas turbine are included. A collection of data of all processes included, extraction of minerals, processing of raw material, production of the components, operation of the SOFC/GT process and transports between all these processes. These data are then added up and weighted in impact categories to evaluate the total environmental impact of the SOFC/GT process. All these steps are performed according to the ISO 14040-series. The stand-alone most contributing phase during the life cycle of the SOFC/GT process was found to be the production of the SOFC. All processes during the production of the SOFC are carried out under laboratory circumstances, which require more energy and materials than if the processes were commercialised and optimised. For the SOFC/GT process to be competitive with other energy converting processes regarding the discharges of emissions to the air, the use of

  17. Microstructural evolution of nanosized Ce0.8Gd0.2O1.9/Ni infiltrate in a Zr0.84Y0.16O1.92-Sr0.94Ti0.9Nb0.1O3-δ based SOFC anode under electrochemical evaluation

    DEFF Research Database (Denmark)

    Zhang, Wei; Kuhn, Luise Theil; Ramos, Tania

    are of paramount importance for performance and performance stability. Therefore an accurate understanding of the microstructure evolution during electrochemical operation will facilitate evaluating performances of SOFC anodes, and in turn optimize its design. Here we report a wealth of microstructural...... investigations of Ce0.8Gd0.2O1.9/Ni (hereafter CGO/Ni)-infiltrated Zr0.84Y0.16O1.92 composited Sr0.94Ti0.9Nb0.1O3-δ (STN94/8YSZ) anode in a symmetric cell design under a short electrochemical evaluation test (fingerprint test), applying electrochemical impedance spectroscopy (EIS) at mild 3% H2O/H2 and harsh 50...

  18. Development of Osaka gas type planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Iha, M.; Shiratori, A.; Chikagawa, O. [Murata Mfg. Co., Ltd., Shiga (Japan)] [and others

    1996-12-31

    Osaka Gas Co. has been developing a planar type SOFC (OG type SOFC) which has a suitable structure for stacking. Murata Mfg. Co. has begun to develop the OG type SOFC stack through joint program since 1993. Figure 1 shows OG type cell structure. Because each cell is sustained by cell holders acting air manifold, the load of upper cell is not put on the lower cells. Single cell is composed of 3-layered membrane and LaCrO{sub 3} separator. 5 single cells are mounted on the cell holder, connected with Ni felt electrically, and bonded by glassy material sealant. We call the 5-cell stack a unit. Stacking 13 units, we succeeded 870 W generation in 1993. But the power density was low, 0.11 Wcm{sup -2} because of crack in the electrolyte and gas leakage at some cells.

  19. Test laboratories for elementary cells of a solid oxide fuel cell (SOFC); Laboratoire d`essais de cellules elementaires d`une pile a combustible a oxyde solide (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Guerin, F.

    1998-01-01

    The solid oxide furl (SOFC) cell could well be the fuel most suited to stationary applications. Its high working temperature allows it to high value heat which can be used to increase electrical output (by the addition of a gas turbine), or to produce steam for heating or an industrial process. test laboratory for electrochemical cells has been created to test elementary cells whose dimensions do not exceed 5 x 5 cm. The SOFC, consisting of a ceramic sheet, is maintained in an oven at around 900 deg. C. It can produce a maximum continuous current of 25 A at a voltage of 0.7 V on an electronic charge. Each test lasts at least 500 hours. Investigation of the prototype cells is intended to establish their electrochemical characteristics: activity, ionic and electronic conductivity, polarization curve stability behaviour under fast transient electronic regime. In parallel, modelings are performed and will be validated by these different tests results

  20. Thermodynamical simulation for solid oxide (SOFC) type fuel cells with ethanol direct internal reforming; Simulacao termodinamica para celulas a combustivel do tipo SOFC com reforma interna direta do etanol

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Aline Lima da; Malfatti, Celia de Fraga; Heck, Nestor Cezar [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais (PPGEM)]. E-mail: als14br2000@yahoo.com.br; Mello, Celso Gustavo [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Quimica (PPGEQ); Halmenschlager, Cibele Melo [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais (PPGEM). Lab. de Materiais Ceramicos

    2008-07-01

    In SOFC, high operative temperature allows the direct conversion of ethanol into H{sub 2} to take place in the electrochemical cell. Direct internal reforming of ethanol, however, can produce undesirable products that diminish system efficiency and, in the case of carbon deposition over the anode, may occur the breakdown of the electrode. In this way, thermodynamic analysis is fundamental to predict the product distribution as well as the conditions favorable for carbon to precipitate inside the cell. Equilibrium determinations are performed by the Gibbs energy minimization method, using the GRG algorithm. Thermodynamic conditions for carbon deposition were analyzed, in order to establish temperature ranges and H{sub 2}O/ethanol ratios where carbon precipitation is not feasible. A mathematical relationship between Lagrange multipliers and carbon activity is presented, unveiling the carbon activity in atmosphere. The effect of the type of solid electrolyte (O{sup 2-} or H{sup +} conducting) on carbon formation is also investigated. The results of this work are in agreement with previous results reported in literature using the stoichiometric method. (author)

  1. Analysis of the perovskite structure LaxSr1-xCryMn1-yO3-δ with potential application as an anode for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado Flores, J.J.

    2017-07-01

    Solid oxide fuel cells (SOFC) are complex devices that offer great advantages over conventional manner in which electrical energy is produced. Many of these advantages revolve around the environmental impact and particularly energy efficiency. However, progress in the field of these devices operating at high temperatures require the continuous search for new materials with advanced properties, optimization in manufacturing, cutting edge technologies for the processing of its main components (anode-electrolyte-cathode-seal) and low manufacturing costs. Here, the perovskite structure material LaxSr1-xCryMn1-yO3-δ (LSCM) is efficient, stable redox environments, has low manufacturing cost and is optimized for SOFC applications. Its properties compare favorably with the compound Ni/YSZ using hydrogen as a fuel; and when methane is used, it requires only 3% moisture to prevent carbon formation, which is much lower compared to when used Ni/YSZ (50% moisture). The LSCM material allows a SOFC cell operate at intermediate temperatures around 700°C. This article provides a brief review of the excellent properties and potential presented by this perovskite. (Author)

  2. Performance analysis of a SOFC under direct internal reforming conditions

    Energy Technology Data Exchange (ETDEWEB)

    Janardhanan, Vinod M.; Deutschmann, Olaf [Institute for Chemical Technology and Polymer Chemistry, Engesserstr 20, D-76131 Karlsruhe, University of Karlsruhe (Germany); Heuveline, Vincent [Institute for Applied and Numerical Mathematics, Kaiserstr. 12, D-76128 Karlsruhe (Germany)

    2007-10-11

    This paper presents the performance analysis of a planar solid-oxide fuel cell (SOFC) under direct internal reforming conditions. A detailed solid-oxide fuel cell model is used to study the influences of various operating parameters on cell performance. Significant differences in efficiency and power density are observed for isothermal and adiabatic operational regimes. The influence of air number, specific catalyst area, anode thickness, steam to carbon (s/c) ratio of the inlet fuel, and extend of pre-reforming on cell performance is analyzed. In all cases except for the case of pre-reformed fuel, adiabatic operation results in lower performance compared to isothermal operation. It is further discussed that, though direct internal reforming may lead to cost reduction and increased efficiency by effective utilization of waste heat, the efficiency of the fuel cell itself is higher for pre-reformed fuel compared to non-reformed fuel. Furthermore, criteria for the choice of optimal operating conditions for cell stacks operating under direct internal reforming conditions are discussed. (author)

  3. Performance analysis of a SOFC under direct internal reforming conditions

    Science.gov (United States)

    Janardhanan, Vinod M.; Heuveline, Vincent; Deutschmann, Olaf

    This paper presents the performance analysis of a planar solid-oxide fuel cell (SOFC) under direct internal reforming conditions. A detailed solid-oxide fuel cell model is used to study the influences of various operating parameters on cell performance. Significant differences in efficiency and power density are observed for isothermal and adiabatic operational regimes. The influence of air number, specific catalyst area, anode thickness, steam to carbon (s/c) ratio of the inlet fuel, and extend of pre-reforming on cell performance is analyzed. In all cases except for the case of pre-reformed fuel, adiabatic operation results in lower performance compared to isothermal operation. It is further discussed that, though direct internal reforming may lead to cost reduction and increased efficiency by effective utilization of waste heat, the efficiency of the fuel cell itself is higher for pre-reformed fuel compared to non-reformed fuel. Furthermore, criteria for the choice of optimal operating conditions for cell stacks operating under direct internal reforming conditions are discussed.

  4. Sulfur Tolerant Solid Oxide Fuel Cell for Coal Syngas Application: Experimental Study on Diverse Impurity Effects and Fundamental Modeling of Electrode Kinetics

    Science.gov (United States)

    Gong, Mingyang

    With demand over green energy economy, fuel cells have been developed as a promising energy conversion technology with higher efficiency and less emission. Solid oxide fuel cells (SOFC) can utilize various fuels in addition to hydrogen including coal derived sygas, and thus are favored for future power generation due to dependence on coal in electrical industry. However impurities such as sulfur and phosphorous present in coal syngas in parts per million (p.p.m.) levels can severely poison SOFC anode typically made of Ni/yttria-stabilized-zirconia (Ni-YSZ) and limit SOFC applicability in economically derivable fuels. The focus of the research is to develop strategy for application of high performance SOFC in coal syngas with tolerance against trace impurities such as H2S and PH3. To realize the research goal, the experimental study on sulfur tolerant anode materials and examination of various fuel impurity effects on SOFC anode are combined with electrochemical modeling of SOFC cathode kinetics in order to benefit design of direct-coal-syngas SOFC. Tolerant strategy for SOFC anode against sulfur is studied by using alternative materials which can both mitigate sulfur poisoning and function as active anode components. The Ni-YSZ anode was modified by incorporation of lanthanum doped ceria (LDC) nano-coatings via impregnation. Cell test in coal syngas containing 20 ppm H2S indicated the impregnated LDC coatings inhibited on-set of sulfur poisoning by over 10hrs. Cell analysis via X-ray photon spectroscopy (XPS), X-ray diffraction (XRD) and electrochemistry revealed LDC coatings reacted with H2S via chemisorptions, resulting in less sulfur blocking triple--phase-boundary and minimized performance loss. Meanwhile the effects of PH3 impurity on SOFC anode is examined by using Ni-YSZ anode supported SOFC. Degradation of cell is found to be irreversible due to adsorption of PH3 on TPB and further reaction with Ni to form secondary phases with low melting point. The

  5. Thermodynamic Model of a Very High Efficiency Power Plant based on a Biomass Gasifier, SOFCs, and a Gas Turbine

    Directory of Open Access Journals (Sweden)

    P V Aravind

    2012-07-01

    Full Text Available Thermodynamic calculations with a power plant based on a biomass gasifier, SOFCs and a gas turbine are presented. The SOFC anode off-gas which mainly consists of steam and carbon dioxides used as a gasifying agent leading to an allothermal gasification process for which heat is required. Implementation of heat pipes between the SOFC and the gasifier using two SOFC stacks and intercooling the fuel and the cathode streams in between them has shown to be a solution on one hand to drive the allothermal gasification process and on the other hand to cool down the SOFC. It is seen that this helps to reduce the exergy losses in the system significantly. With such a system, electrical efficiency around 73% is shown as achievable.

  6. Progress in Metal-Supported Axial-Injection Plasma Sprayed Solid Oxide Fuel Cells Using Nanostructured NiO-Y0.15Zr0.85O1.925 Dry Powder Anode Feedstock

    Science.gov (United States)

    Metcalfe, C.; Harris, J.; Kuhn, J.; Marr, M.; Kesler, O.

    2013-06-01

    A composite NiO-Y0.15Zr0.85O1.925 (YSZ) agglomerated feedstock having nanoscale NiO and YSZ primary particles was used to fabricate anodes having sub-micrometer structure. These anodes were incorporated into two different metal-supported SOFC architectures, which differ in the order of electrode deposition. The composition of the composite Ni-YSZ anodes is controllable by selection of the agglomerate size fraction and standoff distance, while the porosity is controllable by selection of agglomerate size fraction and addition of a sacrificial pore-forming material. A bi-layer anode was fabricated having a total porosity of 33% for the diffusion layer and 23% porosity for the functional layer. A power density of 630 mW/cm2 was obtained at 750 °C in humidified H2 with cells having the bi-layer anode deposited on the metal support. Cells having the cathode deposited on the metal support showed poor performance due to a significant number of vertical cracks through the electrolyte, allowing excessive gas cross-over between the anode and the cathode compartments.

  7. Symmetry breaking and electrical conductivity of La0.7Sr0.3Cr0.4Mn0.6O3-δ perovskite as SOFC anode material

    International Nuclear Information System (INIS)

    Reyes-Rojas, A.; Alvarado-Flores, J.; Esparza-Ponce, H.; Esneider-Alcala, M.; Espitia-Cabrera, I.; Torres-Moye, E.

    2011-01-01

    Research highlights: → Perovskite-type La 0.7 Sr 0.3 Cr 0.4 Mn 0.6 O 3-δ -NiO nucleation kinetics. Symmetry-breaking by introducing Ni 2+ cations at 1050 deg. C. Phase transition from high temperature aristotype R3-bar c to hettotype I4/mmm. At low Ni concentration ρ resistivity decreases when increasing the temperature. For Ni concentration higher than 25% ρ resistivity increases. - Abstract: This work is focused on nanocrystalline solid oxide fuel cell synthesis and characterization (SOFC) anodes of La 0.7 Sr 0.3 Cr 0.4 Mn 0.6 O 3-δ (perovskite-type) with Nickel. Perovskite-type oxide chemical reactivity, nucleation kinetics and phase composition related with La 0.7 Sr 0.3 Cr 0.4 Mn 0.6 O 3-δ -NiO to La 0.7 Sr 0.3 Cr 0.4 Mn 0.6 O 3-δ -Ni transformation have been analyzed. SOFC anode powders were obtained by sol-gel synthesis, using polyvinyl alcohol as an organic precursor to get a porous cermet electrode after sintering at 1365 deg. C and oxide reduction by hydrogen at 800 deg. C/1050 deg. C for 8 h in a horizontal tubular reactor furnace under 10% H 2 /N 2 atmosphere. Composite powders were compressed into 10-mm diameter discs with 25-75 wt% Ni. Electrical and structural characterization by four-point probe method for conductivity, scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Rietveld method were carried out. Symmetry-breaking by phase transition from high temperature aristotype R3-bar c to hettotype I4/mmm has been identified and confirmed by XRD and Rietveld method which can be produced by introducing Ni 2+ cations in the perovskite solid solution. Rietveld analysis suggests that Ni contents are directly proportional to La 0.7 Sr 0.3 Cr 0.4 Mn 0.6 NiO 3.95 tetragonal structure cell volume and inversely proportional to Ni cubic structure cell volume after reduction at 1050 deg. C. Kinetic analysis indicated that the Johnson-Mehl-Avrami equation is able to provide a good fit to phase

  8. Accelerated creep in solid oxide fuel cell anode supports during reduction

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Makowska, Malgorzata Grazyna; Greco, Fabio

    2016-01-01

    To evaluate the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. The creep of reduced Ni-YSZ anode support at operating conditions has been...... studied previously. In this work a newly discovered creep phenomenon taking place during the reduction is reported. This relaxes stresses at a much higher rate (∼ x104) than creep during operation. The phenomenon was studied both in three-point bending and uniaxial tension. Differences between the two...... measurements could be explained by newly observed stress promoted reduction. Finally, samples exposed to a small tensile stress (∼ 0.004 MPa) were observed to expand during reduction, which is in contradiction to previous literature. These observations suggest that release of internal residual stresses between...

  9. Solid oxide fuel cell anode image segmentation based on a novel quantum-inspired fuzzy clustering

    Science.gov (United States)

    Fu, Xiaowei; Xiang, Yuhan; Chen, Li; Xu, Xin; Li, Xi

    2015-12-01

    High quality microstructure modeling can optimize the design of fuel cells. For three-phase accurate identification of Solid Oxide Fuel Cell (SOFC) microstructure, this paper proposes a novel image segmentation method on YSZ/Ni anode Optical Microscopic (OM) images. According to Quantum Signal Processing (QSP), the proposed approach exploits a quantum-inspired adaptive fuzziness factor to adaptively estimate the energy function in the fuzzy system based on Markov Random Filed (MRF). Before defuzzification, a quantum-inspired probability distribution based on distance and gray correction is proposed, which can adaptively adjust the inaccurate probability estimation of uncertain points caused by noises and edge points. In this study, the proposed method improves accuracy and effectiveness of three-phase identification on the micro-investigation. It provides firm foundation to investigate the microstructural evolution and its related properties.

  10. Promising Ni-Fe-LSGMC anode compatible with lanthanum gallate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Wang Shizhong [Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States)], E-mail: shizwang@sohu.com; He, Qiong [Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China); Liu Meilin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States)], E-mail: meilin.liu@mse.gatech.edu

    2009-06-01

    A number of composite materials in the Ni-Fe-LSGMC family have been studied as potential anodes for solid oxide fuel cells (SOFCs) based on strontium, magnesium, and cobalt doped lanthanum gallate electrolyte (LSGMC). The results show that Ni reacts with LSGMC especially under reducing conditions at high temperatures, resulting in high contact resistance, large electrode polarization, and poor performance. The reaction between Ni and LSGMC depends strongly on the composition and pre-sintering temperature of LSGMC, the concentration of iron in the electrode, and the processing and operating temperatures. Under proper conditions, Ni-Fe-LSGMC5 could be a promising high-performance anode with good compatibility with LSGMC5 electrolyte.

  11. Promising Ni-Fe-LSGMC anode compatible with lanthanum gallate electrolyte

    International Nuclear Information System (INIS)

    Wang Shizhong; He, Qiong; Liu Meilin

    2009-01-01

    A number of composite materials in the Ni-Fe-LSGMC family have been studied as potential anodes for solid oxide fuel cells (SOFCs) based on strontium, magnesium, and cobalt doped lanthanum gallate electrolyte (LSGMC). The results show that Ni reacts with LSGMC especially under reducing conditions at high temperatures, resulting in high contact resistance, large electrode polarization, and poor performance. The reaction between Ni and LSGMC depends strongly on the composition and pre-sintering temperature of LSGMC, the concentration of iron in the electrode, and the processing and operating temperatures. Under proper conditions, Ni-Fe-LSGMC5 could be a promising high-performance anode with good compatibility with LSGMC5 electrolyte.

  12. Fundamental researches of SOFC in Russia

    Energy Technology Data Exchange (ETDEWEB)

    Demin, A.K.; Neuimin, A.D.; Perfiliev, M.V. [Institute of High Temperatures Electrochemistry, Ekaterinburg (Russian Federation)

    1996-04-01

    The main results of research on ZrO{sub 2}-based solid electrolytes, electrodes and interconnects are reviewed. The mathematical models of the processes in SOFC are considered. Two types of SOFC stacks composed of tubular and block cells, as well the results of their tests are described.

  13. Manufacturing of cells and stacks for SOFC development, test and demonstration projects and SOFC hotbox design development

    Energy Technology Data Exchange (ETDEWEB)

    2008-09-15

    The purpose of this project is to support the continued SOFC development through manufacturing process optimization and manufacturing of SOFC cells and stacks. These cells and stacks will serve as a necessary base for the development activities and for the establishment of a number of test and demonstration activities. The manufacture will also help provide operating experience and reduce manufacturing cost. Another main focus of the manufacturing is to assure technical improvements and reliability. It is imperative to the eventual success of the technology that test and demonstration is carried out in the pre-market conditions that will exist for the next years in the three market segments targeted by TOFC (Distributed generation, micro CHP and APU incl. marine APU). Finally, the project also includes development activities focusing on the stack-system interface (hotbox design development) and on dealing with transients and start up and shut down times, which is of particular importance for APU and micro CHP applications. Three topics are addressed:1) Cell manufacture, including production development, capacity lift and manuf. of cells for test and demonstration; 2) Stack manufacture and test, including a test facility, stack manuf. and test of stacks in a system at HCV; 3) Hotbox design development, including design, prototype construction and testing. The progress of this project is documented. Major achievements are successful manufacture of adequate amounts of cells and stacks according to the application. Furthermore significant over-performance in design, construction and test of a methanol based hotbox prototype as well as publication of this. (au)

  14. Raman Spectroscopy of Solid Oxide Fuel Cells: Technique Overview and Application to Carbon Deposition Analysis

    KAUST Repository

    Maher, R. C.; Duboviks, V.; Offer, G. J.; Kishimoto, M.; Brandon, N. P.; Cohen, L. F.

    2013-01-01

    Raman spectroscopy is a powerful characterization tool for improving the understanding of solid oxide fuel cells (SOFCs), capable of providing direct, molecularly specific information regarding the physical and chemical processes occurring within functional SOFCs in real time. In this paper we give a summary of the technique itself and highlight ex situ and in situ studies that are particularly relevant for SOFCs. This is followed by a case study of carbon formation on SOFC Ni-based anodes exposed to carbon monoxide (CO) using both ex situ and in situ Raman spectroscopy combined with computational simulations. In situ measurements clearly show that carbon formation is significantly reduced for polarized SOFCs compared to those held at open circuit potential (OCP). Ex situ Raman mapping of the surfaces showed clear variations in the rate of carbon formation across the surface of polarized anodes. Computational simulations describing the geometry of the cell showed that this is due to variations in gas access. These results demonstrate the ability of Raman spectroscopy in combination with traditional characterization tools, to provide detailed understanding of critical processes occurring within functional SOFCs. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Raman Spectroscopy of Solid Oxide Fuel Cells: Technique Overview and Application to Carbon Deposition Analysis

    KAUST Repository

    Maher, R. C.

    2013-07-30

    Raman spectroscopy is a powerful characterization tool for improving the understanding of solid oxide fuel cells (SOFCs), capable of providing direct, molecularly specific information regarding the physical and chemical processes occurring within functional SOFCs in real time. In this paper we give a summary of the technique itself and highlight ex situ and in situ studies that are particularly relevant for SOFCs. This is followed by a case study of carbon formation on SOFC Ni-based anodes exposed to carbon monoxide (CO) using both ex situ and in situ Raman spectroscopy combined with computational simulations. In situ measurements clearly show that carbon formation is significantly reduced for polarized SOFCs compared to those held at open circuit potential (OCP). Ex situ Raman mapping of the surfaces showed clear variations in the rate of carbon formation across the surface of polarized anodes. Computational simulations describing the geometry of the cell showed that this is due to variations in gas access. These results demonstrate the ability of Raman spectroscopy in combination with traditional characterization tools, to provide detailed understanding of critical processes occurring within functional SOFCs. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Development of a solid oxide fuel cell (SOFC) automotive auxiliary power unit (APU) fueled by gasoline

    International Nuclear Information System (INIS)

    DeMinco, C.; Mukerjee, S.; Grieve, J.; Faville, M.; Noetzel, J.; Perry, M.; Horvath, A.; Prediger, D.; Pastula, M.; Boersma, R.; Ghosh, D.

    2000-01-01

    This paper describes the design and the development progress of a 3 to 5 auxiliary power unit (APU) based on a gasoline fueled solid oxide fuel cell (SOFC). This fuel cell was supplied reformate gas (reactant) by a partial oxidation (POx) catalytic reformer utilizing liquid gasoline and designed by Delphi Automotive Systems. This reformate gas consists mainly of hydrogen, carbon monoxide and nitrogen and was fed directly in to the SOFC stack without any additional fuel reformer processing. The SOFC stack was developed by Global Thermoelectric and operates around 700 o C. This automotive APU produces power to support future 42 volt vehicle electrical architectures and loads. The balance of the APU, designed by Delphi Automotive Systems, employs a packaging and insulation design to facilitate installation and operation on-board automobiles. (author)

  17. Solid oxide fuel cells with apatite-type lanthanum silicate-based electrolyte films deposited by radio frequency magnetron sputtering

    Science.gov (United States)

    Liu, Yi-Xin; Wang, Sea-Fue; Hsu, Yung-Fu; Wang, Chi-Hua

    2018-03-01

    In this study, solid oxide fuel cells (SOFCs) containing high-quality apatite-type magnesium doped lanthanum silicate-based electrolyte films (LSMO) deposited by RF magnetron sputtering are successfully fabricated. The LSMO film deposited at an Ar:O2 ratio of 6:4 on an anode supported NiO/Sm0.2Ce0·8O2-δ (SDC) substrate followed by post-annealing at 1000 °C reveals a uniform and dense c-axis oriented polycrystalline structure, which is well adhered to the anode substrate. A composite SDC/La0·6Sr0·4Co0·2Fe0·8O3-δ cathode layer is subsequently screen-printed on the LSMO deposited anode substrate and fired. The SOFC fabricated with the LSMO film exhibits good mechanical integrity. The single cell with the LSMO layer of ≈2.8 μm thickness reports a total cell resistance of 1.156 and 0.163 Ωcm2, open circuit voltage of 1.051 and 0.982 V, and maximum power densities of 0.212 and 1.490 Wcm-2 at measurement temperatures of 700 and 850 °C, respectively, which are comparable or superior to those of previously reported SOFCs with yttria stabilized zirconia electrolyte films. The results of the present study demonstrate the feasibility of deposition of high-quality LSMO films by RF magnetron sputtering on NiO-SDC anode substrates for the fabrication of SOFCs with good cell performance.

  18. Cathode-Electrolyte Interfaces with CGO Barrier Layers in SOFC

    DEFF Research Database (Denmark)

    Knibbe, Ruth; Hjelm, Johan; Menon, Mohan

    2010-01-01

    Electron microscopy characterization across the cathode–electrolyte interface of two different types of intermediate temperature solid oxide fuel cells (IT-SOFC) is performed to understand the origin of the cell performance disparity. One IT-SOFC cell had a sprayed-cosintered Ce0.90Gd0.01O1.95 (CGO...

  19. Improved ceramic anodes for SOFCs with modified electrode/electrolyte interface

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain; Høgh, Jens Valdemar Thorvald; Zhang, Wei

    2012-01-01

    The electrode performance of solid oxide fuel cell anode with Pd nanoparticles at the interface of ScYSZ electrolyte and Sr0.94Ti0.9Nb0.1O3 (STN) electrode introduced in the form of metal functional layer have been investigated at temperatures below 600 °C. A metal functional layer consisting of Pd...... was deposited by magnetron sputtering. Effecting from heat treatments, Pd nanoparticles with particle sizes in the range of 5–20 nm were distributed at the interface, and throughout the backbone. The polarization resistance of the modified STN reduced to 30 Ωcm2 at 600 °C, which is three times less than...... an unmodified STN backbone. In order to improve the anode performance further, Pd and Gd-doped CeO2 electrocatalysts were infiltrated into the STN backbone. The modified interface with Pd nanoparticles in combination with nanostructured electrocatalyst by infiltration resulted in polarisation resistances of 0...

  20. Development of a 1 kW Class SOFC Stack using Doped Lanthanum Gallate

    Energy Technology Data Exchange (ETDEWEB)

    Akikusa, J.; Adachi, K.; Yamada, T.; Akbay, T.; Murakami, N.; Chitose, N.; Hoshino, K.; Hosoi, K.; Yoshida, H.; Sasaki, T.; Inagaki, T.; Ishihara, T.; Takita, Y.

    2002-06-01

    The performance of lanthanum gallate based SOFC has been investigated as a high-energy conversion device. A planar type SOFC which could operate at temperatures below 800 {sup o}C has been jointly developed. As an electrolyte material, lanthanum gallate (LaGaO{sub 3}) with substitutions of Sr for the La site and Mg and Co for the Ga site (LSGMC) was used. The synthesis technique for large-sized cell production has been established, and the performance of a self- supported diameter 154 mm cell with 200 {mu}m electrolyte thickness is investigated. The output power of 50 W has been obtained with a conversion efficiency [LHV] of 45 % for a single cell. In addition, a metallic separator made of stainless steel was chosen and tested successfully for a seal-less stack. The output power of 1 kW by means of the stack of 18 cells has been achieved for the first time utilizing lanthanum gallate. Moreover, NiO-SDC composite powders were prepared by the spray pyrolysis method and used for the anode on 100 {mu}m thickness LSGMC electrolyte with a combination of samarium cobaltite for the cathode. The power density of as high as 1.8 W/cm{sup 2} at 0.7 V terminal voltage was achieved at 800{sup o}C. (author)

  1. Mixed fuel strategy for carbon deposition mitigation in solid oxide fuel cells at intermediate temperatures.

    Science.gov (United States)

    Su, Chao; Chen, Yubo; Wang, Wei; Ran, Ran; Shao, Zongping; Diniz da Costa, João C; Liu, Shaomin

    2014-06-17

    In this study, we propose and experimentally verified that methane and formic acid mixed fuel can be employed to sustain solid oxide fuel cells (SOFCs) to deliver high power outputs at intermediate temperatures and simultaneously reduce the coke formation over the anode catalyst. In this SOFC system, methane itself was one part of the fuel, but it also played as the carrier gas to deliver the formic acid to reach the anode chamber. On the other hand, the products from the thermal decomposition of formic acid helped to reduce the carbon deposition from methane cracking. In order to clarify the reaction pathways for carbon formation and elimination occurring in the anode chamber during the SOFC operation, O2-TPO and SEM analysis were carried out together with the theoretical calculation. Electrochemical tests demonstrated that stable and high power output at an intermediate temperature range was well-maintained with a peak power density of 1061 mW cm(-2) at 750 °C. With the synergic functions provided by the mixed fuel, the SOFC was running for 3 days without any sign of cell performance decay. In sharp contrast, fuelled by pure methane and tested at similar conditions, the SOFC immediately failed after running for only 30 min due to significant carbon deposition. This work opens a new way for SOFC to conquer the annoying problem of carbon deposition just by properly selecting the fuel components to realize their synergic effects.

  2. Validating the technological feasibility of yttria-stabilized zirconia-based semiconducting-ionic composite in intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Cai, Yixiao; Wang, Baoyuan; Wang, Yi; Xia, Chen; Qiao, Jinli; van Aken, Peter A.; Zhu, Bin; Lund, Peter

    2018-04-01

    YSZ as the electrolyte of choice has dominated the progressive development of solid oxide fuel cell (SOFC) technologies for many years. To enable SOFCs operating at intermediate temperatures of 600 °C or below, major technical advances were built on a foundation of a thin-film YSZ electrolyte, NiO anode, and perovskite cathode, e.g. La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF). Inspired by functionalities in engineered heterostructure interfaces, the present work uses the components from state-of-the-art SOFCs, i.e, the anode NiO-YSZ and the cathode LSCF-YSZ, or the convergence of all three components, i.e., NiO-YSZ-LSCF, to fabricate semiconductor-ionic membranes (SIMs) and devices. A series of proof-of-concept fuel cell devices are designed by using each of the above SIMs sandwiched between two semiconducting Ni0.8Co0.15Al0.05LiO2-δ (NCAL) layers. We systematically compare these novel designs at 600 °C with two reference fuel cells: a commercial product of anode-supported YSZ electrolyte thin-film cell, and a lab-assembled fuel cell with a conventional configuration of NiO-YSZ (anode)/YSZ (electrolyte)/LSCF-YSZ (cathode). In comparison to the reference cells, the SIM device in a configuration of NCAL/NiO-YSZ-LSCF/NCAL reaches more than 3-fold enhancement of the maximum power output. By using spherical aberration-corrected transmission electron microscopy and spectroscopy approaches, this work offers insight into the mechanisms underlying SIM-associated SOFC performance enhancement.

  3. Danish strategy for developing SOFC fuel cells 2010-2020; Dansk strategi for udvikling af SOFC-braendselsceller 2010-2020

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.; Linderoth, S. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Themsen, J. (Dantherm Power A/S, Hobro (Denmark)); Richter, A.B.; Hansen, Hakon J.; Holm-Larsen, H.; Andersen, Claus V. (Topsoe Fuel Cell A/S, Lyngby (Denmark))

    2010-09-15

    SOFC fuel cells are a promising technology for efficient production of electricity. The technology is expected to contribute very significantly to climate and environmental goals, security of supply of energy, increased employment and exports. Denmark has a very strong technology position within the SOFC area based on years of cooperation between Topsoe Fuel Cell and Risoe DTU as well as a later developed relationship with Dantherm Power. The Danish players have received more than DKK 250 million in public funding. With this support and the players' own funding (approx. two times higher than public support), the players managed over the past 10 years to bring development of SOFC technology significantly closer to the market. This strategy has been prepared by the Danish players in the field and gives a picture of the required overall development needs in the coming years. Technology development has reached the stage where in the coming years demonstrations on a larger scale have to be launched. The focus is basically on three valuable market segments: micro power and heat, auxiliary power for mobile applications, and decentralized power and CHP, which all have a great potential for market penetration internationally. When the market is established in one or more of these segments, other business opportunities must be explored for other applications based on the established technological platform. The road to commercialization is a long process that begins with demonstrations and later introduction of commercial products. The primary actors are currently the largest companies and institutions but as the number of produced fuel cell units increases, job creation with subcontractors and other directly related businesses and research centres will increase. A conservative estimate of market size worldwide is 2-4 GW of installed capacity per. year representing an annual turnover of 15-30 billion DKK and 10.000-20.000 more jobs. The export ratio is expected to exceed

  4. An in situ near-ambient pressure X-ray Photoelectron Spectroscopy study of Mn polarised anodically in a cell with solid oxide electrolyte

    International Nuclear Information System (INIS)

    Bozzini, Benedetto; Amati, Matteo; Bocchetta, Patrizia; Dal Zilio, Simone; Knop-Gericke, Axel; Vesselli, Erik; Kiskinova, Maya

    2015-01-01

    This paper reports an in situ study of the anodic behavior of a model solid oxide electrolysis cell (SOEC) by means of near-ambient pressure X-ray Photoelectron Spectroscopy (XPS) combined with near edge X-ray absorption fine structure (NEXAFS) measurements. The focus is on the anodic surface chemistry of MnO x , a model anodic material already considered in cognate SOFC-related studies, during electrochemical operation in CO 2 , CO 2 /H 2 O and H 2 O ambients. The XPS and NEXAFS results we obtained, complemented by electrochemical measurements and SEM characterisation, reveal the chemical evolution of Mn under electrochemical control. MnO is the stable chemical form at open-circuit potential (OCP), while Mn 3 O 4 forms under anodic polarisation in all the investigated gas ambients. Carbon deposits are present on the Mn electrode at OCP, but they are readily oxidised under anodic conditions. Prolonged operation of the MnO x anode leads to pitting of the Mn films, damaging of the triple-phase boundary region and also to formation of discontinuities in the Mn patch. This is accompanied by chemical transformations of the electrolyte and formation of ZrC without impact on the surface chemistry of the Mn-based anode

  5. Microstructural degradation of Ni-YSZ anodes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Thyden, K.

    2008-03-15

    Ni-YSZ cermets have been used as anode materials in SOFCs for more than 20 years. Despite this fact, the major cause of degradation within the Ni-YSZ anode, namely Ni sintering / coarsening, is still not fully understood. Even if microstructural studies of anodes in tested cells are of technological relevance, it is difficult to identify the effect from isolated parameters such as temperature, fuel gas composition and polarization. Model studies of high temperature aged Ni-YSZ cermets are generally performed in atmospheres containing relatively low concentrations of H2O. In this work, the microstructural degradation in both electrochemically longterm tested cells and high-temperature aged model materials are studied. Since Ni particle sintering / coarsening is attributed to be the major cause of anode degradation, this subject attains the primary focus. A large part of the work is focused on improving microstructural techniques and shows that the application of low acceleration voltages (<= 1 kV) in a FE-SEM makes it possible to obtain two useful types of contrast between the phases in Ni-YSZ composites. By changing between the ordinary lateral SE detector and the inlens detector, using similar microscope settings, two very different sample characteristics are probed: 1) The difference in secondary emission coefficient, delta, between the percolating and non-percolating Ni is maximized in the low-voltage range due to a high delta for the former and the suppression of delta by a positive charge for the latter. This difference yields a contrast between the two phases which is picked up by an inlens secondary electron detector. 2) The difference in backscatter coefficient, eta, between Ni and YSZ is shown to increase with decreasing voltage. The contrast is illustrated in images collected by the normal secondary detector since parts of the secondary signals are generated by backscattered electrons. High temperature aging experiments of model Ni-YSZ anode cermets show

  6. The Design of Connection Solid Oxide Fuel Cell (SOFC) Integrated Grid with Three-Phase Inverter

    Science.gov (United States)

    Darjat; Sulistyo; Triwiyatno, Aris; Thalib, Humaid

    2018-03-01

    Fuel cell technology is a relatively new energy-saving technology that has the potential to replace conventional energy technologies. Among the different types of generation technologies, fuel cells is the generation technologies considered as a potential source of power generation because it is flexible and can be placed anywhere based distribution system. Modeling of SOFC is done by using Nernst equation. The output power of the fuel cell can be controlled by controlling the flow rate of the fuels used in the process. Three-phase PWM inverter is used to get the form of three-phase voltage which same with the grid. In this paper, the planning and design of the SOFC are connected to the grid.

  7. Thermodynamic model and parametric analysis of a tubular SOFC module

    Science.gov (United States)

    Campanari, Stefano

    Solid oxide fuel cells (SOFCs) have been considered in the last years as one of the most promising technologies for very high-efficiency electric energy generation from natural gas, both with simple fuel cell plants and with integrated gas turbine-fuel cell systems. Among the SOFC technologies, tubular SOFC stacks with internal reforming have emerged as one of the most mature technology, with a serious potential for a future commercialization. In this paper, a thermodynamic model of a tubular SOFC stack, with natural gas feeding, internal reforming of hydrocarbons and internal air preheating is proposed. In the first section of the paper, the model is discussed in detail, analyzing its calculating equations and tracing its logical steps; the model is then calibrated on the available data for a recently demonstrated tubular SOFC prototype plant. In the second section of the paper, it is carried out a detailed parametric analysis of the stack working conditions, as a function of the main operating parameters. The discussion of the results of the thermodynamic and parametric analysis yields interesting considerations about partial load SOFC operation and load regulation, and about system design and integration with gas turbine cycles.

  8. Pre-coating of LSCM perovskite with metal catalyst for scalable high performance anodes

    KAUST Repository

    Boulfrad, Samir; Cassidy, Mark; Djurado, Elisabeth; Irvine, John Ts S; Jabbour, Ghassan E.

    2013-01-01

    then dispersed into organic based vehicles to form a screen-printable ink which was deposited and fired to form SOFC anode layers. Electrochemical tests show a considerable enhancement of the pre-coated anode performances under 50 ml/min wet H2 flow

  9. A SOFC-based integrated gasification fuel cell cycle with CO2 capture

    NARCIS (Netherlands)

    Spallina, V.; Romano, M.C.; Campanari, S.; Lozza, G.

    2011-01-01

    The application of solid oxide fuel cells (SOFC) in gasification-based power plants would represent a turning point in the power generation sector, allowing to considerably increase the electric efficiency of coal-fired power stations. Pollutant emissions would also be significantly reduced in

  10. Status of SOFCo SOFC technology development

    Energy Technology Data Exchange (ETDEWEB)

    Privette, R.; Perna, M.A.; Kneidel, K. [SOFCo, Alliance, OH (United States)] [and others

    1996-12-31

    SOFCo, a Babcock & Wilcox/Ceramatec Research & Development Limited Partnership, is a collaborative research and development venture to develop technologies related to planar, solid-oxide fuel cells (SOFCs). SOFCo has successfully demonstrated a kW-class, solid-oxide fuel cell module operating on pipeline natural gas. The SOFC system design integrates the air preheater and the fuel processor with the fuel cell stacks into a compact test unit; this is the platform for multi-kW modules. The cells, made of tape-cast zirconia electrolyte and conventional electrode materials, exhibit excel lent stability in single-cell tests approaching 40,000 hours of operation. Stack tests using 10-cm and 15-cm cells with ceramic interconnects also show good performance and stability in tests for many thousands of hours.

  11. Analysis of cathode materials of perovskite structure for solid oxide fuel cells, sofc s; Analisis de materiales catodicos de estructura perovskita para celdas de combustible de oxido solido, sofcs

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado F, J.; Espino V, J.; Avalos R, L. [Universidad Michoacana de San Nicolas de Hidalgo, Facultad de Ingenieria Quimica, Santiago Tapia 403, Morelia, Michoacan (Mexico)

    2015-07-01

    Fuel cells directly and efficiently convert the chemical energy of a fuel into electrical energy. Of the various types of fuel cells, the solid oxide (Sofc), combine the advantages in environmentally benign energy generation with fuel flexibility. However, the need for high operating temperatures (800 - 1000 grades C) has resulted in high costs and major challenges in relation to the compatibility the cathode materials. As a result, there have been significant efforts in the development of intermediate temperature Sofc (500 - 700 grades C). A key obstacle for operation in this temperature range is the limited activity of traditional cathode materials for electrochemical reduction oxygen. In this article, the progress of recent years is discussed in cathodes for Sofc perovskite structure (ABO{sub 3}), more efficient than the traditionally used La{sub 1-x}Sr{sub x}MnO{sub 3-δ} (LSM) or (La, Sr) CoO{sub 3}. Such is the case of mixed conductors (MIEC) double perovskite structure (A A B{sub 2}O{sub 5+δ}) using different doping elements as La, Sr, Fe, Ti, Cr, Sm, Co, Cu, Pr, Nd, Gd, dy, Mn, among others, which could improve the operational performance of existing cathode materials, promoting the development of optimized intermediate temperature Sofc designs. (Author)

  12. Nanostructured Solid Oxide Fuel Cell Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Sholklapper, Tal Zvi [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    The ability of Solid Oxide Fuel Cells (SOFC) to directly and efficiently convert the chemical energy in hydrocarbon fuels to electricity places the technology in a unique and exciting position to play a significant role in the clean energy revolution. In order to make SOFC technology cost competitive with existing technologies, the operating temperatures have been decreased to the range where costly ceramic components may be substituted with inexpensive metal components within the cell and stack design. However, a number of issues have arisen due to this decrease in temperature: decreased electrolyte ionic conductivity, cathode reaction rate limitations, and a decrease in anode contaminant tolerance. While the decrease in electrolyte ionic conductivities has been countered by decreasing the electrolyte thickness, the electrode limitations have remained a more difficult problem. Nanostructuring SOFC electrodes addresses the major electrode issues. The infiltration method used in this dissertation to produce nanostructure SOFC electrodes creates a connected network of nanoparticles; since the method allows for the incorporation of the nanoparticles after electrode backbone formation, previously incompatible advanced electrocatalysts can be infiltrated providing electronic conductivity and electrocatalysis within well-formed electrolyte backbones. Furthermore, the method is used to significantly enhance the conventional electrode design by adding secondary electrocatalysts. Performance enhancement and improved anode contamination tolerance are demonstrated in each of the electrodes. Additionally, cell processing and the infiltration method developed in conjunction with this dissertation are reviewed.

  13. Study of a SOFC-PEM hybrid system

    International Nuclear Information System (INIS)

    Fillman, B.; Bjornbom, P.; Sylwan, C.

    2004-01-01

    'Full text:' In the present project a system study of a SOFC-PEM hybrid system is in progress. Positive synergy effects are expected when combining a SOFC system with a PEM system. By combining the advantages of each fuel cell type it is promising that the hybrid system has higher overall efficiency than a SOFC-only system or a reformer-PEM system. A SOFC stack produces electricity and a reformate gas that can be further processed to hydrogen by the shift reaction. The produced hydrogen can be used by PEM stack in order to produce further electricity. In the PEM system case the complex fuel reformer processing could be eliminated. The simulations were performed with the flowsheeting simulation software Aspen Plus. (author)

  14. Thermodynamic analysis of Direct Urea Solid Oxide Fuel Cell in combined heat and power applications

    Science.gov (United States)

    Abraham, F.; Dincer, I.

    2015-12-01

    This paper presents a comprehensive steady state modelling and thermodynamic analysis of Direct Urea Solid Oxide Fuel Cell integrated with Gas Turbine power cycle (DU-SOFC/GT). The use of urea as direct fuel mitigates public health and safety risks associated with the use of hydrogen and ammonia. The integration scheme in this study covers both oxygen ion-conducting solid oxide fuel cells (SOFC-O) and hydrogen proton-conducting solid oxide fuel cells (SOFC-H). Parametric case studies are carried out to investigate the effects of design and operating parameters on the overall performance of the system. The results reveal that the fuel cell exhibited the highest level of exergy destruction among other system components. Furthermore, the SOFC-O based system offers better overall performance than that with the SOFC-H option mainly due to the detrimental reverse water-gas shift reaction at the SOFC anode as well as the unique configuration of the system.

  15. Plant Characteristics af a Multi-Fuel Sofc-Stirling Hybrid Configuration

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2012-01-01

    A novel hybrid system ( kWe) for an average family house including heating is proposed. The system investigated, contains of a Solid Oxide Fuel Cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle is fed to the bottoming Stirling engine wherein additional power...... efficiency compared with the stand alone Stirling engine or SOFC plant. For the SOFC and Stirling combined configuration, the overall power production has increased by about 10% compared to the stand alone SOFC plant. System efficiencies of about 60% are achieved which is remarkable for such small plant...

  16. Simulation of SOFCs based power generation system using Aspen

    Directory of Open Access Journals (Sweden)

    Pianko-Oprych Paulina

    2017-12-01

    Full Text Available This study presents a thermodynamic Aspen simulation model for Solid Oxide Fuel Cells, SOFCs, based power generation system. In the first step, a steady-state SOFCs system model was developed. The model includes the electrochemistry and the diffusion phenomena. The electrochemical model gives good agreement with experimental data in a wide operating range. Then, a parametric study has been conducted to estimate effects of the oxygen to carbon ratio, O/C, on reformer temperature, fuel cell temperature, fuel utilization, overall fuel cell performance, and the results are discussed in this paper. In the second step, a dynamic analysis of SOFCs characteristic has been developed. The aim of dynamic modelling was to find the response of the system against the fuel utilization and the O/C ratio variations. From the simulations, it was concluded that both developed models in the steady and dynamic state were reasonably accurate and can be used for system level optimization studies of the SOFC based power generation system.

  17. Carbonate fuel cell anodes

    Science.gov (United States)

    Donado, Rafael A.; Hrdina, Kenneth E.; Remick, Robert J.

    1993-01-01

    A molten alkali metal carbonates fuel cell porous anode of lithium ferrite and a metal or metal alloy of nickel, cobalt, nickel/iron, cobalt/iron, nickel/iron/aluminum, cobalt/iron/aluminum and mixtures thereof wherein the total iron content including ferrite and iron of the composite is about 25 to about 80 percent, based upon the total anode, provided aluminum when present is less than about 5 weight percent of the anode. A process for production of the lithium ferrite containing anode by slipcasting.

  18. Thermal stress analysis of a planar SOFC stack

    Science.gov (United States)

    Lin, Chih-Kuang; Chen, Tsung-Ting; Chyou, Yau-Pin; Chiang, Lieh-Kwang

    The aim of this study is, by using finite element analysis (FEA), to characterize the thermal stress distribution in a planar solid oxide fuel cell (SOFC) stack during various stages. The temperature profiles generated by an integrated thermo-electrochemical model were applied to calculate the thermal stress distributions in a multiple-cell SOFC stack by using a three-dimensional (3D) FEA model. The constructed 3D FEA model consists of the complete components used in a practical SOFC stack, including positive electrode-electrolyte-negative electrode (PEN) assembly, interconnect, nickel mesh, and gas-tight glass-ceramic seals. Incorporation of the glass-ceramic sealant, which was never considered in previous studies, into the 3D FEA model would produce more realistic results in thermal stress analysis and enhance the reliability of predicting potential failure locations in an SOFC stack. The effects of stack support condition, viscous behavior of the glass-ceramic sealant, temperature gradient, and thermal expansion mismatch between components were characterized. Modeling results indicated that a change in the support condition at the bottom frame of the SOFC stack would not cause significant changes in thermal stress distribution. Thermal stress distribution did not differ significantly in each unit cell of the multiple-cell stack due to a comparable in-plane temperature profile. By considering the viscous characteristics of the glass-ceramic sealant at temperatures above the glass-transition temperature, relaxation of thermal stresses in the PEN was predicted. The thermal expansion behavior of the metallic interconnect/frame had a greater influence on the thermal stress distribution in the PEN than did that of the glass-ceramic sealant due to the domination of interconnect/frame in the volume of a planar SOFC assembly.

  19. SOFC: Processes and characteristics of ageing behaviour

    International Nuclear Information System (INIS)

    Gerganov, T.; Grigorov, S.; Kozhukharov, S.

    2005-01-01

    The high-temperature solid oxide fuel cell (SOFC) is convenient for the environmental friendly and efficient conversion of chemical into electric energy. During the last decade the development of planar SOFC stacks with metallic interconnects has made considerable progress in both size and power density. The improvement of durability in long-term operation of planar SOFC components is one of the main fields for stationary applications. Ageing of stacks can be caused by various processes, e.g. corrosion of metallic plates, degradation of ceramic parts and chemical interactions on electrodes/electrolyte or interconnect/electrode interface. Namely, these processes are object of the overview in the present work. The most important characteristics of ageing behavior are subjected to analysis and discussion, as well. Moreover a correlation between ageing process and single cell performance will be given

  20. A conceptual design of catalytic gasification fuel cell hybrid power plant with oxygen transfer membrane

    Science.gov (United States)

    Shi, Wangying; Han, Minfang

    2017-09-01

    A hybrid power generation system integrating catalytic gasification, solid oxide fuel cell (SOFC), oxygen transfer membrane (OTM) and gas turbine (GT) is established and system energy analysis is performed. In this work, the catalytic gasifier uses steam, recycled anode off-gas and pure oxygen from OTM system to gasify coal, and heated by hot cathode off-gas at the same time. A zero-dimension SOFC model is applied and verified by fitting experimental data. Thermodynamic analysis is performed to investigate the integrated system performance, and system sensitivities on anode off-gas back flow ratio, SOFC fuel utilization, temperature and pressure are discussed. Main conclusions are as follows: (1) System overall electricity efficiency reaches 60.7%(HHV) while the gasifier operates at 700 °C and SOFC at 850 °C with system pressure at 3.04 bar; (2) oxygen enriched combustion simplify the carbon-dioxide capture process, which derives CO2 of 99.2% purity, but results in a penalty of 6.7% on system electricity efficiency; (3) with SOFC fuel utilization or temperature increasing, the power output of SOFC increases while GT power output decreases, and increasing system pressure can improve both the performance of SOFC and GT.

  1. New methodology of preparation support for solid oxide fuel cells using different pore forming agent

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, Raigenis da P.; Guedes, Bruna C.F.; Silva, Marcos A. da; Carvalho, Luiz F.V. de; Boaventura, Jaime S. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica; Pontes, Luiz A.M. [Universidade Federal da Bahia (EP/UFBA), Salvador, BA (Brazil). Escola Politecnica. Programa de Pos-Graduacao em Engenharia Quimica

    2008-07-01

    The development of environment-friendly energy sources has been of the most important scientific and technological area. Solid oxide fuel cells (SOFC) are very promising alternative for their ability to handle renewable fuels with low emissions and high efficiency. However, this device requires massive improvement before commercial application. This work studies the pore formation in the cell anode and cathode with NaHCO{sub 3} or citric acid, comparing to graphite. The three agents make pore with similar features, but the use of NaHCO{sub 3} and citric acid considerably improves the adhesion of the electrode-electrolyte interface, critical characteristic for good cell efficiency. The prepared anode-electrolyte-cathode structure was studied by SEM technique. The SOFC prepared using citric acid was tested with gaseous ethanol, natural gas and hydrogen. For all these three fuels the SOFC shows virtually no overpotential, indicating the good ionic conductance of the electrodes-electrolyte interface.. (author)

  2. SOFC solid oxide fuel cell power plants for the decentralised electric energy supply; SOFC-Brennstoffzellen-Kraftwerke fuer die dezentrale elektrische Energieversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Fogang Tchonla, Etienne

    2012-07-01

    To use the fuel cell economically, the efficiency of the system must still be raised so that it can be set up in the market. Within the scope of analysis on this topic, a 120-kW-SOFC-demonstration power plant was to be considered. Since not enough information about the demonstration power plant from the operator was available for the investigation, we had to calculate with the help of the known technical data of similar power plants. After that a model was build and simulated by means of MATLAB/Simulink. Before that the single power plant components were being described. Two of them (the boost converter as well as the inverter) were looked at more thoroughly. As a result of the analysis, it was found that a standard inverter which had been conceived for other applications, for example, Photovoltaic or Wind Power can also be used for fuel cells. Unfortunately, this was not the case for the added boost converter. It had to be precisely conceived for the used fuel cell type. After this discovery information was won for the realization of a 1-MW-Fuel Cell Power Plant. The topology of the 1-MW-power plant was fixed on the basis of the 120-kW-system. A parallel connection of eight 120-kW SOFC-fuel cell aggregates is intended, as well as a connection at the outlet side 120-kW boost converters. A standard inverter with 1 MW electrical power as well as a 1-MVA-transformer could be used for the realization of the 1-MW-power plant. The binding of the power plant in the three-phase current network was examined in view of the norms, laws and connection conditions. Beside the distinction of the operating forms of the power plant (parallel or isolated operation) the security of the plant was emphasized with regard to quick fault recognition, safe supply line isolation in the fault case as well as a compliance of the prescribed regulations. To verify the calculated results as well as the provided models, a 10-kW-labor sample was built and examined in the lab. This experimental

  3. Experimental investigations and modeling of direct internal reforming of biogases in tubular solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Lanzini, A.; Leone, P.; Pieroni, M.; Santarelli, M. [Dipartimento di Energetica, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10129, Torino (Italy); Beretta, D.; Ginocchio, S. [Centro Ricerca e Sviluppo, Edison S.p.a, Via La Pira 2, IT-10028 Trofarello, Torino (Italy)

    2011-10-15

    Biogas-fed Solid Oxide Fuel Cell (SOFC) systems can be considered as interesting integrated systems in the framework of distributed power generation. In particular, bio-methane and bio-hydrogen produced from anaerobic digestion of organic wastes represent renewable carbon-neutral fuels for high efficiency electrochemical generators. With such non-conventional mixtures fed to the anode of the SOFC, the interest lies in understanding the multi-physics phenomena there occurring and optimizing the geometric and operation parameters of the SOFC, while avoiding operating and fuel conditions that can lead to or accelerate degradation processes. In this study, an anode-supported (Ni-YSZ) tubular SOFC was considered; the tubular geometry enables a relatively easy separation of the air and fuel reactants and it allows one to evaluate the temperature field of the fuel gas inside the tube, which is strictly related to the electrochemical and heterogeneous chemical reactions occurring within the anode volume. The experiments have been designed to analyze the behavior of the cell under different load and fuel utilization (FU) conditions, providing efficiency maps for both fuels. The experimental results were used to validate a multi-physics model of the tubular cell. The model showed to be in good agreement with the experimental data, and was used to study the sensitive of some selected geometrical parameters modification over the cell performances. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. SOFC Systems with Improved Reliability and Endurance

    Energy Technology Data Exchange (ETDEWEB)

    Ghezel-Ayagh, Hossein [Fuelcell Energy, Incorporated, Danbury, CT (United States)

    2015-12-31

    The overall goal of this U.S. Department of Energy (DOE) sponsored project was the development of Solid Oxide Fuel Cell (SOFC) technology suitable for ultra-efficient central power generation systems utilizing coal and natural gas fuels and featuring greater than 90% carbon dioxide capture. The specific technical objective of this project was to demonstrate, via analyses and testing, progress towards adequate stack life (≥ 4 years) and stack performance stability (degradation rate ≤ 0.2% per 1000 hours) in a low-cost SOFC stack design. This final technical report summarizes the progress made during the project period of 27 months. Significant progress was made in the areas of cell and stack technology development, stack module development, sub-scale module tests, and Proof-of-Concept Module unit design, fabrication and testing. The work focused on cell and stack materials and designs, balance-of-plant improvements, and performance evaluation covering operating conditions and fuel compositions anticipated for commercially-deployed systems. In support of performance evaluation under commercial conditions, this work included the design, fabrication, siting, commissioning, and operation of a ≥ 50 kWe proof-of-concept module (PCM) power plant, based upon SOFC cell and stack technology developed to date by FuelCell Energy, Inc. (FCE) under the Office of Fossil Energy’s Solid Oxide Fuel Cells program. The PCM system was operated for at least 1000 hours on natural gas fuel at FCE’s facility. The factory cost of the SOFC stack was estimated to be at or below the DOE’s high-volume production cost target (2011 $).

  5. Vaporization of materials in the operation of high temperature fuel cells (SOFCs); Verdampfung von Werkstoffen beim Betrieb von Hochtemperaturbrennstoffzellen (SOFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Stanislowski, M.

    2006-07-01

    One of the main problems concerning the development of state of the art planar SOFCs are the occurrence of ageing effects in long term application. To a great deal these effects are caused by the release of volatile Cr-species from metallic interconnects which leads to an inhibition of the electrochemical processes at the cathode resulting in a rapid degradation of the cell performance. A goal in further development of SOFC-systems is the reduction of the operation temperature of the cell from currently 800 C to 700 C and below. For this purpose alternative electrolyte materials with higher oxygen ion conductivities have to be developed. Doped lanthanum gallates have been identified as promising materials. However for these materials a depletion of Ga by vaporization has been observed under anodic conditions which may lead to a destruction of their electrolyte properties. The aim of this work is the study of the vaporization processes leading to the mentioned degradation effects. For this purpose an experimental setup according to the transpiration method has been developed. Concerning the vaporization of chromium the Cr release rates of the main ferritic interconnect alloys, namely Crofer 22 APU, ZMG 232, E-Brite, IT-10, IT-11, IT-14 and Ducrolloy as well as a variety of Ni- and Co-base superalloys and stainless steels with different contents of Al, Si, Ti, Mn, W, Ni and Co were measured at 800 C in air and compared to each other. The alloys that form an upper layer of Cr-Mn-spinel on top of the grown chromia scale showed a reduction of the Cr release by 61-75 % compared to pure chromia scales whereas alloys with an outer Co3O4(s) scale had a by more than 90 % reduced Cr release. For the former alloys a significant vaporization of Mn under anodic conditions could be detected. Concerning the vaporization of doped lanthanum gallates the vaporization rates of the elements Ga, Mg, Sr and La were measured as function time, temperature, gas flow rate and stoichiometry

  6. Study on dynamic performance of SOFC

    Science.gov (United States)

    Zhan, Haiyang; Liang, Qianchao; Wen, Qiang; Zhu, Runkai

    2017-05-01

    In order to solve the problem of real-time matching of load and fuel cell power, it is urgent to study the dynamic response process of SOFC in the case of load mutation. The mathematical model of SOFC is constructed, and its performance is simulated. The model consider the influence factors such as polarization effect, ohmic loss. It also takes the diffusion effect, thermal effect, energy exchange, mass conservation, momentum conservation. One dimensional dynamic mathematical model of SOFC is constructed by using distributed lumped parameter method. The simulation results show that the I-V characteristic curves are in good agreement with the experimental data, and the accuracy of the model is verified. The voltage response curve, power response curve and the efficiency curve are obtained by this way. It lays a solid foundation for the research of dynamic performance and optimal control in power generation system of high power fuel cell stack.

  7. Mixed conductor anodes: Ni as electrocatalyst for hydrogen conversion

    DEFF Research Database (Denmark)

    Primdahl, S.; Mogensen, Mogens Bjerg

    2002-01-01

    Five types of anodes for solid oxide fuel cells (SOFC) are examined on an yttria-stabilised zirconia (YSZ) electrolyte by impedance spectroscopy at 850 degreesC in hydrogen. The examined porous anodes are a Ni/Zr(0.92)Y(0.16)O(2.08) (Ni/YSZ) cermet, a Ni/Ce(0.9)Gd(0.1)O(1.95) (Ni/CGI) cermet, a Ce......(0.6)Gd(0.4)O(1.8) (CG4) ceramic, a La(0.75)Sr(0.25)Cr(0.97)V(0.03)O(3) (LSCV) ceramic and a Ti(0.22) Y(0.16)Zr(0.92)O(2.52) (TiYSZ) ceramic, Addition of small amounts ( approximate to I w/o) of Ni to the electrode surface is found to improve electrode performance on mixed electronic and ionic...

  8. Innovative Seals for Solid Oxide Fuel Cells (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Raj

    2008-06-30

    A functioning SOFC requires different type of seals such as metal-metal, metal-ceramic, and ceramic-ceramic. These seals must function at high temperatures between 600--900{sup o}C and in oxidizing and reducing environments of the fuels and air. Among the different type of seals, the metal-metal seals can be readily fabricated using metal joining, soldering, and brazing techniques. However, the metal-ceramic and ceramic-ceramic seals require significant research and development because the brittle nature of ceramics/glasses can lead to fracture and loss of seal integrity and functionality. Consequently, any seals involving ceramics/glasses require a significant attention and technology development for reliable SOFC operation. This final report is prepared to describe the progress made in the program on the needs, approaches, and performance of high temperature seals for SOFC. In particular, a new concept of self-healing glass seals is pursued for making seals between metal-ceramic material combinations, including some with a significant expansion mismatch.

  9. Electrochemical performance of Ni0.8Cu0.2/Ce0.8Gd0.2O1.9 cermet anodes with functionally graded structures for intermediate-temperature solid oxide fuel cell fueled with syngas

    Science.gov (United States)

    Miyake, Michihiro; Iwami, Makoto; Takeuchi, Mizue; Nishimoto, Shunsuke; Kameshima, Yoshikazu

    2018-06-01

    The electrochemical performance of layered Ni0.8Cu0.2/Ce0.8Gd0.2O1.9 (GDC) cermet anodes is investigated for intermediate-temperature solid oxide fuel cells (IT-SOFCs) at 600 °C using humidified (3% H2O) model syngas with a molar ratio of H2/CO = 3/2 as the fuel. From the results obtained, the electrochemical performance of the functionally graded multi-layered anodes is found to be superior to the mono-layered anodes. The test cell with a bi-layered anode consisting of 100 mass% Ni0.8Cu0.2/0 mass% GDC (10M/0E) and 70 mass% Ni0.8Cu0.2/30 mass% GDC (7M/3E) exhibits high power density. The test cell with a tri-layered anode consisting of 10M/0E, 7M/3E, and 50 mass% Ni0.8Cu0.2/50 mass% GDC (5M/5E) exhibits an even higher power density, suggesting that 10M/0E and 5M/5E layers contribute to the current collecting part and active part, respectively.

  10. Use of wastewater treatment plant biogas for the operation of Solid Oxide Fuel Cells (SOFCs).

    Science.gov (United States)

    Lackey, Jillian; Champagne, Pascale; Peppley, Brant

    2017-12-01

    Solid Oxide Fuel Cells (SOFCs) perform well on light hydrocarbon fuels, and the use of biogas derived from the anaerobic digestion (AD) of municipal wastewater sludges could provide an opportunity for the CH 4 produced to be used as a renewable fuel. Greenhouse gas (GHG), NO x , SO x , and hydrocarbon pollutant emissions would also be reduced. In this study, SOFCs were operated on AD derived biogas. Initially, different H 2 dilutions were tested (N 2 , Ar, CO 2 ) to examine the performance of tubular SOFCs. With inert gases as diluents, a decrease in cell performance was observed, however, the use of CO 2 led to a higher decrease in performance as it promoted the reverse water-gas shift (WGS) reaction, reducing the H 2 partial pressure in the gas mixture. A model was developed to predict system efficiency and GHG emissions. A higher electrical system efficiency was noted for a steam:carbon ratio of 2 compared to 1 due to the increased H 2 partial pressure in the reformate resulting from higher H 2 O concentration. Reductions in GHG emissions were estimated at 2400 tonnes CO 2 , 60 kg CH 4 and 18 kg N 2 O. SOFCs were also tested using a simulated biogas reformate mixture (66.7% H 2 , 16.1% CO, 16.5% CO 2 , 0.7% N 2 , humidified to 2.3 or 20 mol% H 2 O). Higher humidification yielded better performance as the WGS reaction produced more H 2 with additional H 2 O. It was concluded that AD-derived biogas, when cleaned to remove H 2 S, Si compounds, halides and other contaminants, could be reformed to provide a clean, renewable fuel for SOFCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Co-sintering of CGO/NIO-CGO bilayers for solid oxide fuel cell

    International Nuclear Information System (INIS)

    Neto, P.P.B.; Grilo, J.P.F.; Souza, G.L.; Macedo, D.A.; Paskocimas, C.A.; Nascimento, R.M.

    2012-01-01

    Reducing the operating temperature of solid oxide fuel cells (SOFC) for the range between 500 and 700°C is one of the challenges which more has aroused the interest of research in SOFC in recent years. In this context, the bilayer anode/electrolyte composed of a porous support based on Ni-doped ceria (anode) and a ceria doped gadolinia (CGO) electrolyte, presents itself as one of the half-cell configurations of the most interest towards the production of electricity in the operating logic of a SOFC. In this work, CGO films were successfully prepared on NiO-CGO substrates using the resources of the screen-printing technique. The bi-layers were co-sintered between 1350 and 1450 ° C for 4 h and then characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS). The results showed good adhesion at the film/substrate interface and no cracks in the films. (author)

  12. Layered SmBaCuCoO5+δ and SmBaCuFeO5+δ perovskite oxides as cathode materials for proton-conducting SOFCs

    International Nuclear Information System (INIS)

    Nian Qiong; Zhao Ling; He Beibei; Lin Bin; Peng Ranran; Meng Guangyao; Liu Xingqin

    2010-01-01

    A dense BaCe 0.8 Sm 0.2 O 5+δ (BCS) electrolyte was fabricated on a porous anode by in situ drop-coating to develop a simple and cost-effective route to fabricate proton-conducting solid oxide fuel cells (SOFCs). Layered perovskite-structure oxides SmBaCuCoO 5+δ (SBCC) and SmBaCuFeO 5+δ (SBCF) were prepared and the electrical conductivity, the thermal expansion coefficient and electrochemical performance were investigated as potential cathode materials for proton-conducting SOFCs. Thermal expansion coefficients of SBCC and SBCF were suitable for BCS electrolyte and the electrical conductivity of the SBCC is higher than that of the SBCF. The maximum power density of 449 mW cm 2 and 333 mW cm 2 at 700 o C were obtained for the SBCC/BCS/NiO-BCS and SBCF/BCS/NiO-BCS cells, respectively. The interfacial polarization resistances for SBCC and SBCF cathode are as low as 0.137 Ω cm -2 and 0.196 Ω cm -2 at 700 o C, respectively. The results indicate that the SBCC and SBCF are promising cathode materials for proton-conducting SOFCs.

  13. SOFC seal and cell thermal management

    Science.gov (United States)

    Potnis, Shailesh Vijay [Neenah, WI; Rehg, Timothy Joseph [Huntington Beach, CA

    2011-05-17

    The solid oxide fuel cell module includes a manifold, a plate, a cathode electrode, a fuel cell and an anode electrode. The manifold includes an air or oxygen inlet in communication with divergent passages above the periphery of the cell which combine to flow the air or oxygen radially or inwardly for reception in the center of the cathode flow field. The latter has interconnects providing circuitous cooling passages in a generally radial outward direction cooling the fuel cell and which interconnects are formed of different thermal conductivity materials for a preferential cooling.

  14. Análise termodinâmica de um ciclo de potência com célula a combustível sofc e turbina a vapor = Thermodynamic analysis of a power cycle such as SOFC fuel cell and steam turbine

    Directory of Open Access Journals (Sweden)

    Alexandre Sordi

    2006-01-01

    Full Text Available O objetivo deste artigo foi realizar a análise termodinâmica de um sistema híbrido, SOFC / ST (célula a combustível tipo SOFC e turbina a vapor ST. O combustível considerado para a análise foi o gás metano (biogás produzido por meio da digestão anaeróbica de resíduos orgânicos. A metodologia utilizada foi o balanço de energia dosistema SOFC / ST, considerando a reforma interna do metano na célula a combustível, de forma a obter a sua eficiência elétrica. O resultado foi comparado a um ciclo combinado convencional de turbina a gás e turbina a vapor (GT / ST para potências entre 10 MW e 30MW. A eficiência do sistema híbrido SOFC / ST variou de 61% a 66% em relação ao poder calorífico do metano; e a eficiência do ciclo combinado GT / ST variou de 41% a 55% para o mesmo intervalo de potência. Para geração distribuída a célula a combustível SOFC é atecnologia mais eficiente.The objective of this article was to analyze the thermodynamic of ahybrid system, SOFC / ST (SOFC fuel cell and ST steam turbine. The fuel for the analysis was the gas methane (biogas produced through the anaerobic digestion of the organic residues. The utilized methodology was the energy balance of the system SOFC / ST,considering the internal reforming of methane in the fuel cell, in a way to obtain its electric effectiveness. The result was compared to a conventional combined cycle of gas turbine and steam turbine (GT / ST for powers between 10 MW and 30 MW. The efficiency of the hybrid system SOFC / ST varied from 61 to 66% in relation to the lower heating value of methane; and the efficiency of the combined cycle GT / ST varied from 41 to 55% within the same power interval. For distributed generation, the SOFC fuel cell is the most efficienttechnology.

  15. Study of a hybrid system using solid oxide fuel cells (SOFC) and gas turbine; Estudo de um sistema hibrido empregando celula de combustivel de oxido solido (SOFC) e turbina a gas

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Antonio Carlos Caetano de; Gallo, Giulliano Batelochi; Silveira, Jose Luz [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Energia], e-mail: caetano@feg.unesp.br

    2004-07-01

    In this paper a hybrid solid oxide fuel cell (SOFC) system, applying a combined cycle using gas turbine for rational decentralized energy production is analyzed. The relative concepts about the fuel cell are presented, followed by some chemical and technical information such as the change of Gibbs free energy in isothermal fuel oxidation directly into electricity. This represents a very high fraction of the lower heating value (LHV) of a hydrocarbon fuel. In the next step a methodology for the study of SOFC and gas turbine system is developed, considering the electricity and steam production for a hospital. This methodology is applied to energetic analysis. Natural gas is considered as a fuel. A Sankey Diagram shows that the hybrid SOFC system is a good opportunity to strengthen the decentralized energy production in Brazil. It is necessary to consider that the cogeneration in this version also is a good technical alternative, demanding special methods of design, equipment selection and contractual deals associated to electricity and fuel supply. (author)

  16. Reforming processes for micro combined heat and powersystem based on solid oxide fuel cell

    DEFF Research Database (Denmark)

    Liso, Vincenzo; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2009-01-01

    Solid oxide fuel cell (SOFC) is a promising technology for decentralized power generation and cogeneration. This technology has several advantages: the high electric efficiency, which can be theoretically improved through integration in power cycles; the low emissions; and the possibility of using...... a large variety of gaseous fuels. The high operating temperature (700-1000°C) of SOFCs has a number of consequences, the most important of which are the possibility to partially reform the raw fuel in the fuel cell anode compartment and the possibility to use high quality heat for cogeneration....... In this work, different configurations of SOFC systems for decentralized electricity production are considered and studied. The balance of plant (BoP) components will be identified including fuel and air supply, fuel management, start-up steam, anode re-circulation, exhaust gas heat management, power...

  17. Thermodynamic analysis and optimization of IT-SOFC-based integrated coal gasification fuel cell power plants

    NARCIS (Netherlands)

    Romano, M.C.; Campanari, S.; Spallina, V.; Lozza, G.

    2011-01-01

    This work discusses the thermodynamic analysis of integrated gasification fuel cell plants, where a simple cycle gas turbine works in a hybrid cycle with a pressurized intermediate temperature–solid oxide fuel cell (SOFC), integrated with a coal gasification and syngas cleanup island and a bottoming

  18. SOFC Operation with Real Biogas

    DEFF Research Database (Denmark)

    Hagen, Anke; Winiwarter, Anna; Langnickel, Hendrik

    2017-01-01

    Biogas is a valuable energy source and will be available in future in systems relying on renewables. It is an attractive fuel for solid oxide fuel cells (SOFC), which are able to utilize the carbon contained in the biogas and which produce electricity with high efficiency. In the current paper......, state‐of‐the‐art SOFCs were studied regarding performance and durability in relation to biogas as fuel and considering important contaminants, specifically sulfur. First, the catalytic behavior in relevant synthetic biogas mixtures was studied and the potential of dry reforming was demonstrated....... Successful long term operation of an SOFC under both, conditions of steam and dry reforming, i.e., addition of steam or CO2 to avoid carbon formation was shown. For the steam reforming case a remarkable period of 3,500 h, hereof 3,000 h in the presence of H2S was achieved. Finally, a real biogas from...

  19. Origin of electrolyte-dopant dependent sulfur poisoning of SOFC anodes.

    Science.gov (United States)

    Zeng, ZhenHua; Björketun, Mårten E; Ebbesen, Sune; Mogensen, Mogens B; Rossmeisl, Jan

    2013-05-14

    The mechanisms governing the sulfur poisoning of the triple phase boundary (TPB) of Ni-XSZ (X2O3 stabilized zirconia) anodes have been investigated using density functional theory. The calculated sulfur adsorption energies reveal a clear correlation between the size of the cation dopant X(3+) and the sulfur tolerance of the Ni-XSZ anode; the smaller the ionic radius, the higher the sulfur tolerance. The mechanistic study shows that the size of X(3+) strongly influences XSZ's surface energy, which in turn determines the adhesion of Ni to XSZ. The Ni-XSZ interaction has a direct impact on the Ni-S interaction and on the relative stability of reconstructed and pristine Ni(100) facets at the TPB. Together, these two effects control the sulfur adsorption on the Ni atoms at the TPB. The established relationships explain experimentally observed dopant-dependent anode performances and provide a blueprint for the future search for and preparation of highly sulfur tolerant anodes.

  20. Experimental and modeling study of high performance direct carbon solid oxide fuel cell with in situ catalytic steam-carbon gasification reaction

    Science.gov (United States)

    Xu, Haoran; Chen, Bin; Zhang, Houcheng; Tan, Peng; Yang, Guangming; Irvine, John T. S.; Ni, Meng

    2018-04-01

    In this paper, 2D models for direct carbon solid oxide fuel cells (DC-SOFCs) with in situ catalytic steam-carbon gasification reaction are developed. The simulation results are found to be in good agreement with experimental data. The performance of DC-SOFCs with and without catalyst are compared at different operating potential, anode inlet gas flow rate and operating temperature. It is found that adding suitable catalyst can significantly speed up the in situ steam-carbon gasification reaction and improve the performance of DC-SOFC with H2O as gasification agent. The potential of syngas and electricity co-generation from the fuel cell is also evaluated, where the composition of H2 and CO in syngas can be adjusted by controlling the anode inlet gas flow rate. In addition, the performance DC-SOFCs and the percentage of fuel in the outlet gas are both increased with increasing operating temperature. At a reduced temperature (below 800 °C), good performance of DC-SOFC can still be obtained with in-situ catalytic carbon gasification by steam. The results of this study form a solid foundation to understand the important effect of catalyst and related operating conditions on H2O-assisted DC-SOFCs.

  1. The ways of SOFC systems efficiency increasing

    Energy Technology Data Exchange (ETDEWEB)

    Demin, A.K.; Timofeyeva, N.

    1996-04-01

    The efficiency of solid oxide fuel cells (SOFCs) is described. This paper considers methods to lift the fuel utilization and/or the average cell voltage with the goal of increasing the cell efficiency by improved cell designs.

  2. Status of SOFC development at Siemens

    Energy Technology Data Exchange (ETDEWEB)

    Drenckhahn, W.; Blum, L.; Greiner, H. [Siemens AG, Erlangen (Germany)

    1996-12-31

    The Siemens SOFC development programme reached an important milestone in June 1995. A stack operating with hydrogen and oxygen produced a peak power of 10.7 kW at a current density of 0.7 A/cm{sup 2} and was running for more than 1400 hours. The SOFC configuration is based on a flat metal separator plate using the multiple cell array design. Improved PENs, functional layer and joining technique were implemented. Based on this concept, a 100 kW plant was designed The SOFC development at Siemens has been started in 1990 after a two years preparation phase. The first period with the goal of the demonstration of a 1 kW SOFC stack operation ended in 1993. This important milestone was finally reached in the begin of 1994. The second project phase with the final milestone of a 20 kW module operation will terminate at the end of 1996. This result will form a basis for the next phase in which a 50 to 100 kW pilot plant will be built and tested.

  3. Investigation of nanoporous platinum thin films fabricated by reactive sputtering: Application as micro-SOFC electrode

    Science.gov (United States)

    Jung, WooChul; Kim, Jae Jin; Tuller, Harry L.

    2015-02-01

    Highly porous Pt thin films, with nano-scale porosity, were fabricated by reactive sputtering. The strategy involved deposition of thin film PtOx at room temperature, followed by the subsequent decomposition of the oxide by rapid heat treatment. The resulting films exhibited percolating Pt networks infiltrated with interconnected nanosized pores, critical for superior solid oxide fuel cell cathode performance. This approach is particularly attractive for micro-fabricated solid oxide fuel cells, since it enables fabrication of the entire cell stack (anode/electrolyte/cathode) within the sputtering chamber, without breaking vacuum. In this work, the morphological, crystallographic and chemical properties of the porous electrode were systematically varied by control of deposition conditions. Oxygen reduction reaction kinetics were investigated by means of electrochemical impedance spectroscopy, demonstrating the critical role of nano-pores in achieving satisfactory micro-SOFC cathode performance.

  4. High temperature electrolyte supported Ni-GDC/YSZ/LSM SOFC operation on two-stage Viking gasifier product gas

    DEFF Research Database (Denmark)

    Hofmann, P.; Schweiger, A.; Fryda, L.

    2007-01-01

    and tar traces. The chosen SOFC was electrolyte supported with a nickel/gadolinium-doped cerium oxide (Ni-GDC) anode, known for its carbon deposition resistance. Through humidification the steam to carbon ratio (S/C) was adjusted to 0.5, which results in a thermodynamically carbon free condition...

  5. Investigations on autothermal reforming of kerosene Jet A-1 for supplying solid oxide fuel cells (SOFC); Untersuchungen zur autothermen Reformierung von Kerosin Jet A-1 zur Versorgung oxidkeramischer Festelektrolyt-Brennstoffzellen (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Lenz, B.

    2007-01-25

    The auxiliary power unit of commercial aircraft is a gas turbine producing electric power with an efficiency of 18 %. This APU can be replaced by a fuel cell system, consisting of an autothermal kerosene reformer and a solid oxide fuel cell (SOFC). The fuel is kerosene Jet A-1. The autothermal reforming of Jet A-1 is practically investigated under variation of steam-to-carbon-ratio, air ratio, space velocity, time in operation and reactor pressure on commercial catalysts. Using stationary system simulation the thermodynamic processes of the device is investigated. Finally, the autothermal reformer and the SOFC consisting of 14 cells are coupled. During this test series, I-V-characteristics are measured, fuel utilisation is calculated and the self-sufficient system operation is shown. (orig.)

  6. Modeling and parametric simulations of solid oxide fuel cells with methane carbon dioxide reforming

    International Nuclear Information System (INIS)

    Ni, Meng

    2013-01-01

    Highlights: ► A 2D model is developed for solid oxide fuel cells (SOFCs). ► CH 4 reforming by CO 2 (MCDR) is included. ► SOFC with MCDR shows comparable performance with methane steam reforming SOFC. ► Increasing CO electrochemical oxidation greatly enhances the SOFC performance. ► Effects of potential and temperature on SOFC performance are also discussed. - Abstract: A two-dimensional model is developed to simulate the performance of solid oxide fuel cells (SOFCs) fed with CO 2 and CH 4 mixture. The electrochemical oxidations of both CO and H 2 are included. Important chemical reactions are considered in the model, including methane carbon dioxide reforming (MCDR), reversible water gas shift reaction (WGSR), and methane steam reforming (MSR). It’s found that at a CH 4 /CO 2 molar ratio of 50/50, MCDR and reversible WGSR significantly influence the cell performance while MSR is negligibly small. The performance of SOFC fed with CO 2 /CH 4 mixture is comparable to SOFC running on CH 4 /H 2 O mixtures. The electric output of SOFC can be enhanced by operating the cell at a low operating potential or at a high temperature. In addition, the development of anode catalyst with high activity towards CO electrochemical oxidation is important for SOFC performance enhancement. The model can serve as a useful tool for optimization of the SOFC system running on CH 4 /CO 2 mixtures

  7. Accelerated creep of Ni-YSZ anodes during reduction

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Greco, Fabio; Ni, De Wei

    2014-01-01

    by the thermomechanical history of the stack (e.g. sintering temperature, time at temperature etc.). During operation the stress state will depend on time as stresses are relaxed by creep processes. Creep has mainly been studied at operating conditions, where the Ni-YSZ anode is in the reduced state and YSZ is the main......To evaluate the reliability of solid oxide fuel cell (SOFC) stacks during operation the stress field must be known at all times. This is influenced by external loads, the operating conditions, the particular design of the stack components and their mechanical properties and finally...... load-carrying component. In this work we report on a new creep-reduction phenomenon observed to take place during the reduction process itself, where stresses are relaxed at a rate much faster (~×104) than during operation where the anode is in fully reduced state. Furthermore, samples exposed...

  8. Degradation of solid oxide fuel cells with wood

    International Nuclear Information System (INIS)

    N Frank; M Saule; J Karl

    2006-01-01

    The Technical University of Munich investigates the degradation effects observed on SOFCs when fired with product gases from biomass gasification processes. The TUM has concentrated its research on tubular SOFCs. For this purpose tubular electrolyte-supported SOFCs have been manufactured using commercially available electrolyte tubes, anode foil and cathode paste. The tubular SOFCs were first run with hydrogen and synthetic fuels. Once stable and reproducible results were achieved, tests with product gas from four different biomass gasifiers have started. These gasifiers have been coupled to a gas cleaning device which includes sulphur and particle removal and pre-reforming. Different operation conditions of the gasifiers and the gas cleaning device have been realized and the corresponding fuel cell degradations have been analysed. (authors)

  9. Solid oxide fuel cell (SOFC) materials

    CERN Document Server

    Saravanan, R

    2018-01-01

    Developing materials for SOFC applications is one of the key topics in energy research. The book focuses on manganite structured materials, such as doped lanthanum chromites and lanthanum manganites, which have interesting properties: thermal and chemical stability, mixed ionic and electrical conductivity, electrocatalytic activity, magnetocaloric property and colossal magnetoresistance (CMR).

  10. Anode-supported single-chamber SOFCs based on gadolinia doped ceria electrolytes

    Directory of Open Access Journals (Sweden)

    Morales, M.

    2008-12-01

    Full Text Available The utilization of anode supported electrolytes is a useful strategy to increase the electrical properties of the solid oxide fuel cells, because it is possible to decrease considerably the thickness of the electrolytes. We have prepared successfully singlechamber fuel cells of gadolinia doped ceria electrolytes Ce1-xGdxO2-y (CGO supported on an anode formed by a cermet of Ni-CGO. Mixtures of precursor powders of NiO and gadolinium doped ceria with different particle sizes and compositions were analyzed to obtain optimal bulk porous anodes to be used as anode supported fuel cells. Doped ceria electrolytes were prepared by sol-gel related techniques. Then, ceria based electrolytes were deposited by dip coating at different thickness (15-30 µm using an ink prepared with nanometric powders of electrolytes dispersed in a commercial liquid polymer. Cathodes of La1-xSrxCoO3-s (LSCO were also prepared by sol-gel related techniques and were deposited by dip coating on the electrolyte thick films. Finally, electrical properties were determined in a single-chamber reactor where propane as fuel was mixed with synthetic air above the higher explosive limit. Stable density currents were obtained in these experimental conditions, but flow rates of the carrier gas and propane partial pressure were determinants for the optimization of the electrical properties of the fuel cells.

    La utilización de electrolitos soportados en el ánodo es una estrategia muy útil para mejorar las propiedades eléctricas de las pilas de combustible de óxido sólido, debido a que permiten disminuir considerablemente el espesor de los electrolitos. Para este trabajo, se han preparado exitosamente pilas de combustible de óxido sólido con electrolitos de ceria dopada con Gd, Ce1-xGdxO2-y (CGO soportados sobre un ánodo formado por un cermet de Ni/CGO. Dichas pilas se han

  11. Electrical and stability performance of anode-supported solid oxide fuel cells with strontium- and magnesium-doped lanthanum gallate thin electrolyte

    International Nuclear Information System (INIS)

    Guo Weimin; Liu Jiang; Zhang Yaohui

    2008-01-01

    Anode-supported solid oxide fuel cells (SOFCs) comprising NiO-samarium-doped ceria (SDC) (Sm 0.2 Ce 0.8 O 1.9 ) composite anode, thin tri-layer electrolyte, and La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3 (LSCF)-La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-δ (LSGM) composite cathode were fabricated. The thin tri-layer consisting of an 11-μm thick LSGM electrolyte layer and a 12-μm thick La 0.4 Ce 0.6 O 1.8 (LDC) layer on each side of the LSGM was prepared by centrifugal casting and co-firing technique. The performance of the cells operated with humidified H 2 as fuel and ambient air as oxidant showed a maximum power density of 1.23 W cm -2 at 800 deg. C. A stability test of about 100 h was carried out and some deterioration of output power was observed, while the open circuit voltage (OCV) kept unchanged. Impedance measurements showed that both the electrolyte ohmic resistance and the electrode polarization increased with time and the latter dominated the degradation

  12. Numerical investigation of the effect of operating parameters on a planar solid oxide fuel cell

    International Nuclear Information System (INIS)

    Raj, Abhishek; Sasmito, Agus P.; Shamim, Tariq

    2015-01-01

    Highlights: • Effects of operating parameters on a planar type of SOFC are investigated. • The studies carried out by developing a three dimensional mathematical model. • The cell performance is enhanced at high temperatures and cathode stoichiometry. • Cathode stoichiometry has a high influence on the cell performance. • The effect of anode stoichiometry on the cell performance is low. - Abstract: The three operating parameters – temperature, stoichiometry and the degree of humidification – constitute key factors required to ensure high performance of the solid oxide fuel cell (SOFC). A careful trade-off between performance and parasitic loads is required in order to optimize the output. The present study numerically analyzes the influence of the key operating parameters on the performance of planar type of SOFC and parasitic loads utilizing a validated three dimensional mathematical model which takes into account of the conservation of mass, momentum, species and charge. The numerical results indicate that the cell performance is enhanced at high temperatures and cathode stoichiometry and it declines with increasing cathode relative humidity. Furthermore, cathode stoichiometry is found to have higher influence on the cell performance as compared to the anode stoichiometry. The gain in cell performance however, has to be balanced with the changing parasitic load requirement from pumping, humidification and heating. The results presented herein can assist in the selection of optimum or near-to-optimum operating parameters for high performance planar type SOFC

  13. CFD analysis of a solid oxide fuel cell with internal reforming: Coupled interactions of transport, heterogeneous catalysis and electrochemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Janardhanan, Vinod M.; Deutschmann, Olaf [Institute for Chemical Technology and Polymer Chemistry, Engesserstr. 20, D-76131 Karlsruhe, University of Karlsruhe (TH) (Germany)

    2006-11-22

    Direct internal reforming in solid oxide fuel cell (SOFC) results in increased overall efficiency of the system. Present study focus on the chemical and electrochemical process in an internally reforming anode supported SOFC button cell running on humidified CH{sub 4} (3% H{sub 2} O). The computational approach employs a detailed multi-step model for heterogeneous chemistry in the anode, modified Butler-Volmer formalism for the electrochemistry and Dusty Gas Model (DGM) for the porous media transport. Two-dimensional elliptic model equations are solved for a button cell configuration. The electrochemical model assumes hydrogen as the only electrochemically active species. The predicted cell performances are compared with experimental reports. The results show that model predictions are in good agreement with experimental observation except the open circuit potentials. Furthermore, the steam content in the anode feed stream is found to have remarkable effect on the resulting overpotential losses and surface coverages of various species at the three-phase boundary. (author)

  14. CFD analysis of a solid oxide fuel cell with internal reforming: Coupled interactions of transport, heterogeneous catalysis and electrochemical processes

    Science.gov (United States)

    Janardhanan, Vinod M.; Deutschmann, Olaf

    Direct internal reforming in solid oxide fuel cell (SOFC) results in increased overall efficiency of the system. Present study focus on the chemical and electrochemical process in an internally reforming anode supported SOFC button cell running on humidified CH 4 (3% H 2 O). The computational approach employs a detailed multi-step model for heterogeneous chemistry in the anode, modified Butler-Volmer formalism for the electrochemistry and Dusty Gas Model (DGM) for the porous media transport. Two-dimensional elliptic model equations are solved for a button cell configuration. The electrochemical model assumes hydrogen as the only electrochemically active species. The predicted cell performances are compared with experimental reports. The results show that model predictions are in good agreement with experimental observation except the open circuit potentials. Furthermore, the steam content in the anode feed stream is found to have remarkable effect on the resulting overpotential losses and surface coverages of various species at the three-phase boundary.

  15. Thermodynamic analysis of SOFC (solid oxide fuel cell)–Stirling hybrid plants using alternative fuels

    International Nuclear Information System (INIS)

    Rokni, Masoud

    2013-01-01

    A novel hybrid power system (∼10 kW) for an average family home is proposed. The system investigated contains a solid oxide fuel cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle are fed to a bottoming Stirling engine, at which additional power is generated. Simulations of the proposed system were conducted using different fuels, which should facilitate the use of a variety of fuels depending on availability. Here, the results for natural gas (NG), ammonia, di-methyl ether (DME), methanol and ethanol are presented and analyzed. The system behavior is further investigated by comparing the effects of key factors, such as the utilization factor and the operating conditions under which these fuels are used. Moreover, the effect of using a methanator on the plant efficiency is also studied. The combined system improves the overall electrical efficiency relative to that of a stand-alone Stirling engine or SOFC plant. For the combined SOFC and Stirling configuration, the overall power production was increased by approximately 10% compared to that of a stand-alone SOFC plant. System efficiencies of approximately 60% are achieved, which is remarkable for such small plant sizes. Additionally, heat is also produced to heat the family home when necessary. - Highlights: • Integrating a solid oxide fuel with a Stirling engine • Design of multi-fuel hybrid plants • Plants running on alternative fuels; natural gas, methanol, ethanol, DME and ammonia • Thermodynamic analysis of hybrid SOFC–Stirling engine plants

  16. Development of solid oxide fuel cell technology

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dae Kab; Kim, Sun Jae; Jung, Choong Hwan; Kim, Kyung Hoh; Park, Ji Yun; Oh, Suk Jin [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-01-01

    Solid Oxide Fuel Cell (SOFC) technologies that use zirconium oxide as the electrolyte material were studied in this present report. SOFC exhibits a very high power generation efficiency of over 50 %, and does not discharge pollution materials such as dusts, sulfur dioxide, and nitrogen oxide. Zirconia, Ni/YSZ (yttria stabilized zirconia), and La-Sr-Mn-Oxide materials were developed for the electrolyte material, for the anode, and for the cathode, respectively. After making thin zirconia plate using tape casting process, anode and cathode powders were screen printed on the zirconia plate for fabricating unit cells. A test system composed of a vertical tube furnace, digital multimeter, DC current supplier, and measuring circuit was constructed for testing the unit cell performance. This system was controlled by a home-made computer program. Founded on this unit cell technology and system, a multi-stack SOFC system was studied. This system was composed of 10 unit cells each of them had an electrode area of 40 x 40 mm. Based on this system design, large and thin zirconia plates of 70 x 70 mm in area was fabricated for the electrolyte. Different from in the unit cell system, interconnectors are needed in the multi-stack system for connecting unit cells electrically. For this interconnectors, Inconel 750 alloy was selected, sliced into wafers, machined, surface finished, and then Pt-plated. 55 figs, 8 tabs, 51 refs. (Author).

  17. Development of solid oxide fuel cell technology

    International Nuclear Information System (INIS)

    Kang, Dae Kab; Kim, Sun Jae; Jung, Choong Hwan; Kim, Kyung Hoh; Park, Ji Yun; Oh, Suk Jin

    1995-01-01

    Solid Oxide Fuel Cell (SOFC) technologies that use zirconium oxide as the electrolyte material were studied in this present report. SOFC exhibits a very high power generation efficiency of over 50 %, and does not discharge pollution materials such as dusts, sulfur dioxide, and nitrogen oxide. Zirconia, Ni/YSZ (yttria stabilized zirconia), and La-Sr-Mn-Oxide materials were developed for the electrolyte material, for the anode, and for the cathode, respectively. After making thin zirconia plate using tape casting process, anode and cathode powders were screen printed on the zirconia plate for fabricating unit cells. A test system composed of a vertical tube furnace, digital multimeter, DC current supplier, and measuring circuit was constructed for testing the unit cell performance. This system was controlled by a home-made computer program. Founded on this unit cell technology and system, a multi-stack SOFC system was studied. This system was composed of 10 unit cells each of them had an electrode area of 40 x 40 mm. Based on this system design, large and thin zirconia plates of 70 x 70 mm in area was fabricated for the electrolyte. Different from in the unit cell system, interconnectors are needed in the multi-stack system for connecting unit cells electrically. For this interconnectors, Inconel 750 alloy was selected, sliced into wafers, machined, surface finished, and then Pt-plated. 55 figs, 8 tabs, 51 refs. (Author)

  18. Continued maturing of SOFC cell production technology and development and demonstration of SOFC stacks. Final report

    Energy Technology Data Exchange (ETDEWEB)

    2008-08-15

    The overall objective of the 6385 project was to develop stack materials, components and stack technology including industrial relevant manufacturing methods for cells components and stacks. Furthermore, the project should include testing and demonstration of the stacks under relevant operating conditions. A production of 6.829 cells, twenty 75-cell stacks and a number of small stacks was achieved. Major improvements were also made in the manufacturing methods and in stack design. Two test and demonstration activities were included in the project. The first test unit was established at H.C. OErsted power plant at the Copenhagen waterfront in order to perform test of SOFC stacks. The unit will be used for tests in other projects. The second demonstration unit is the alpha prototype demonstration in a system running on natural gas in Finland. The alpha prototype demonstration system with 24 TOFC (Topsoe Fuel Cell) stacks was established and started running in October 2007 and operational experience was gained in the period from October 2007 to February 2008. (auther)

  19. Materials system for intermediate temperature solid oxide fuel cells based on doped lanthanum-gallate electrolyte

    Science.gov (United States)

    Gong, Wenquan

    2005-07-01

    The objective of this work was to identify a materials system for intermediate temperature solid oxide fuel cells (IT-SOFCs). Towards this goal, alternating current complex impedance spectroscopy was employed as a tool to study electrode polarization effects in symmetrical cells employing strontium and magnesium doped lanthanum gallate (LSGM) electrolyte. Several cathode materials were investigated including strontium doped lanthanum manganite (LSM), Strontium and iron doped lanthanum cobaltate (LSCF), LSM-LSGM, and LSCF-LSGM composites. Investigated Anode materials included nickel-gadolinium or lanthanum doped cerium oxide (Ni-GDC, or Ni-LDC) composites. The ohmic and the polarization resistances of the symmetrical cells were obtained as a function of temperature, time, thickness, and the composition of the electrodes. Based on these studies, the single phase LSM electrode had the highest polarization resistance among the cathode materials. The mixed-conducting LSCF electrode had polarization resistance orders of magnitude lower than that of the LSM-LSGM composite electrodes. Although incorporating LSGM in the LSCF electrode did not reduce the cell polarization resistance significantly, it could reduce the thermal expansion coefficient mismatch between the LSCF electrodes and LSGM electrolyte. Moreover, the polarization resistance of the LSCF electrode decreased asymptotically as the electrode thickness was increased thus suggesting that the electrode thickness needed not be thicker than this asymptotic limit. On the anode side of the IT-SOFC, Ni reacted with LSGM electrolyte, and lanthanum diffusion occurred from the LSGM electrolyte to the GDC barrier layer, which was between the LSGM electrolyte and the Ni-composite anode. However, LDC served as an effective barrier layer. Ni-LDC (70 v% Ni) anode had the largest polarization resistance, while all other anode materials, i.e. Ni-LDC (50 v% Ni), Ni-GDC (70 v% NO, and Ni-GDC (50 v% Ni), had similar polarization

  20. Effectiveness of paper-structured catalyst for the operation of biodiesel-fueled solid oxide fuel cell

    Science.gov (United States)

    Quang-Tuyen, Tran; Kaida, Taku; Sakamoto, Mio; Sasaki, Kazunari; Shiratori, Yusuke

    2015-06-01

    Mg/Al-hydrotalcite (HDT)-dispersed paper-structured catalyst (PSC) was prepared by a simple paper-making process. The PSC exhibited excellent catalytic activity for the steam reforming of model biodiesel fuel (BDF), pure oleic acid methyl ester (oleic-FAME, C19H36O2) which is a mono-unsaturated component of practical BDFs. The PSC exhibited fuel conversion comparable to a pelletized catalyst material, here, conventional Ni-zirconia cermet anode for solid oxide fuel cell (SOFC) with less than one-hundredth Ni weight. Performance of electrolyte-supported cell connected with the PSC was evaluated in the feed of oleic-FAME, and stable operation was achieved. After 60 h test, coking was not observed in both SOFC anode and PSC.

  1. Methane-free biogas for direct feeding of solid oxide fuel cells

    Science.gov (United States)

    Leone, P.; Lanzini, A.; Santarelli, M.; Calì, M.; Sagnelli, F.; Boulanger, A.; Scaletta, A.; Zitella, P.

    This paper deals with the experimental analysis of the performance and degradation issues of a Ni-based anode-supported solid oxide fuel cell fed by a methane-free biogas from dark-anaerobic digestion of wastes by pastry and fruit shops. The biogas is produced by means of an innovative process where the biomass is fermented with a pre-treated bacteria inoculum (Clostridia) able to completely inhibit the methanization step during the fermentation process and to produce a H 2/CO 2 mixture instead of conventional CH 4/CO 2 anaerobic digested gas (bio-methane). The proposed biogas production route leads to a biogas composition which avoids the need of introducing a reformer agent into or before the SOFC anode in order to reformate it. In order to analyse the complete behaviour of a SOFC with the bio-hydrogen fuel, an experimental session with several H 2/CO 2 synthetic mixtures was performed on an anode-supported solid oxide fuel cell with a Ni-based anode. It was found that side reactions occur with such mixtures in the typical thermodynamic conditions of SOFCs (650-800 °C), which have an effect especially at high currents, due to the shift to a mixture consisting of hydrogen, carbon monoxide, carbon dioxide and water. However, cells operated with acceptable performance and carbon deposits (typical of a traditional hydrocarbon-containing biogas) were avoided after 50 h of cell operation even at 650 °C. Experiments were also performed with traditional bio-methane from anaerobic digestion with 60/40 vol% of composition. It was found that the cell performance dropped after few hours of operation due to the formation of carbon deposits. A short-term test with the real as-produced biogas was also successfully performed. The cell showed an acceptable power output (at 800 °C, 0.35 W cm -2 with biogas, versus 0.55 W cm -2 with H 2) although a huge quantity of sulphur was present in the feeding fuel (hydrogen sulphide at 103 ppm and mercaptans up to 10 ppm). Therefore, it

  2. Methane-free biogas for direct feeding of solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Leone, P.; Lanzini, A.; Santarelli, M.; Cali, M. [Dipartimento di Energetica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy); Sagnelli, F.; Boulanger, A.; Scaletta, A.; Zitella, P. [BioEnergy Lab, Environment Park S.p.A., Via Livorno 60, 10144 Turin (Italy)

    2010-01-01

    This paper deals with the experimental analysis of the performance and degradation issues of a Ni-based anode-supported solid oxide fuel cell fed by a methane-free biogas from dark-anaerobic digestion of wastes by pastry and fruit shops. The biogas is produced by means of an innovative process where the biomass is fermented with a pre-treated bacteria inoculum (Clostridia) able to completely inhibit the methanization step during the fermentation process and to produce a H{sub 2}/CO{sub 2} mixture instead of conventional CH{sub 4}/CO{sub 2} anaerobic digested gas (bio-methane). The proposed biogas production route leads to a biogas composition which avoids the need of introducing a reformer agent into or before the SOFC anode in order to reformate it. In order to analyse the complete behaviour of a SOFC with the bio-hydrogen fuel, an experimental session with several H{sub 2}/CO{sub 2} synthetic mixtures was performed on an anode-supported solid oxide fuel cell with a Ni-based anode. It was found that side reactions occur with such mixtures in the typical thermodynamic conditions of SOFCs (650-800 C), which have an effect especially at high currents, due to the shift to a mixture consisting of hydrogen, carbon monoxide, carbon dioxide and water. However, cells operated with acceptable performance and carbon deposits (typical of a traditional hydrocarbon-containing biogas) were avoided after 50 h of cell operation even at 650 C. Experiments were also performed with traditional bio-methane from anaerobic digestion with 60/40 vol% of composition. It was found that the cell performance dropped after few hours of operation due to the formation of carbon deposits. A short-term test with the real as-produced biogas was also successfully performed. The cell showed an acceptable power output (at 800 C, 0.35 W cm{sup -2} with biogas, versus 0.55 W cm{sup -2} with H{sub 2}) although a huge quantity of sulphur was present in the feeding fuel (hydrogen sulphide at 103 ppm and

  3. Laser induced densification of cerium gadolinium oxide: Application to single-chamber solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Mariño, Mariana [École Nationale Supérieure des Mines, SPIN-EMSE, CNRS: UMR 5307, LGF, F-42023 Saint-Étienne (France); Rieu, Mathilde, E-mail: rieu@emse.fr [École Nationale Supérieure des Mines, SPIN-EMSE, CNRS: UMR 5307, LGF, F-42023 Saint-Étienne (France); Viricelle, Jean-Paul [École Nationale Supérieure des Mines, SPIN-EMSE, CNRS: UMR 5307, LGF, F-42023 Saint-Étienne (France); Garrelie, Florence [Université Jean Monnet, Laboratoire Hubert Curien, CNRS: UMR 5516, 42000 Saint-Etienne (France)

    2016-06-30

    Graphical abstract: - Highlights: • CGO surface densifications were induced by UV and IR laser irradiations. • Grain growth or densified cracked surfaces were observed by SEM. • UV laser treatments allow a decrease of gas permeation through electrolyte layer. • Electrical conductivity of the electrolyte was modified by laser treatments. • Grain growth of electrolyte induced by UV laser improved cell performances. - Abstract: In single-chamber solid oxide fuel cells (SC-SOFC), anode and cathode are placed in a gas chamber where they are exposed to a fuel/air mixture. Similarly to conventional dual-chamber SOFC, the anode and the cathode are separated by an electrolyte. However, as in the SC-SOFC configuration the electrolyte does not play tightness role between compartments, this one can be a porous layer. Nevertheless, it is necessary to have a diffusion barrier to prevent the transportation of hydrogen produced locally at the anode to the cathode that reduces fuel cell performances. This study aims to obtain directly a diffusion barrier through the surface densification of the electrolyte Ce{sub 0.9}Gd{sub 0.1}O{sub 1.95} (CGO) by a laser treatment. KrF excimer laser and Yb fiber laser irradiations were used at different fluences and number of pulses to modify the density of the electrolyte coating. Microstructural characterizations confirmed the modifications on the surface of the electrolyte for appropriate experimental conditions showing either grain growth or densified but cracked surfaces. Gas permeation and electrical conductivities of the modified electrolyte were evaluated. Finally SC-SOFC performances were improved for the cells presenting grain growth at the electrolyte surface.

  4. Pressurisation of IP-SOFC technology for second generation hybrid application

    Energy Technology Data Exchange (ETDEWEB)

    Jones, L.

    2005-07-01

    The Integrated Planar Solid Oxide Fuel Cell (IP-SOFC) technology developed by Rolls-Royce plc is a hybrid fuel cell technology considered highly suitable for the distributed power generation market. This report presents the results of a project to examine the technical viability of the IP-SOFC technology and some of the associated hybrid system component technologies under pressurised conditions and to investigate the validity of the predicted pressurisation phenomena. The work included: identification of critical material specifications, construction processes, control parameters, etc; the design and commissioning of two pressurised IP-SOFC test rigs at Rolls Royce in Derby; testing two multi-bundle strips at high temperature and atmospheric pressure; testing an active IP-SOFC bundle at high temperature and pressure; testing an experimental steam reforming unit at high temperature and pressure; testing a novel low pressure drop, off-gas combustor concept under atmospheric and pressurised conditions; design studies to identify key parameters affecting the successful integration and packaging of the fuel cell stack with certain associated hybrid components; and designing a hybrid system experimental verification rig. Significant progress was made in addressing the development challenges associated with the IP-SOFC of leakage, performance, durability, yield and geometry, the reaction rate of steam reforming and emissions from the off-gas combustor. Recommendations for future work are made.

  5. Materials and Components for Low Temperature Solid Oxide Fuel Cells – an Overview

    Directory of Open Access Journals (Sweden)

    D. Radhika

    2013-06-01

    Full Text Available This article summarizes the recent advancements made in the area of materials and components for low temperature solid oxide fuel cells (LT-SOFCs. LT-SOFC is a new trend in SOFCtechnology since high temperature SOFC puts very high demands on the materials and too expensive to match marketability. The current status of the electrolyte and electrode materials used in SOFCs, their specific features and the need for utilizing them for LT-SOFC are presented precisely in this review article. The section on electrolytes gives an overview of zirconia, lanthanum gallate and ceria based materials. Also, this review article explains the application of different anode, cathode and interconnect materials used for SOFC systems. SOFC can result in better performance with the application of liquid fuels such methanol and ethanol. As a whole, this review article discusses the novel materials suitable for operation of SOFC systems especially for low temperature operation.

  6. Development of Plasma-Sprayed Molybdenum Carbide-Based Anode Layers with Various Metal Oxides for SOFC

    Science.gov (United States)

    Faisal, N. H.; Ahmed, R.; Katikaneni, S. P.; Souentie, S.; Goosen, M. F. A.

    2015-12-01

    Air plasma-sprayed (APS) coatings provide an ability to deposit a range of novel fuel cell materials at competitive costs. This work develops three separate types of composite anodes (Mo-Mo2C/Al2O3, Mo-Mo2C/ZrO2, Mo-Mo2C/TiO2) using a combination of APS process parameters on Hastelloy®X for application in intermediate temperature proton-conducting solid oxide fuel cells. Commercially available carbide of molybdenum powder catalyst (Mo-Mo2C) and three metal oxides (Al2O3, ZrO2, TiO2) was used to prepare three separate composite feedstock powders to fabricate three different anodes. Each of the modified composition anode feedstock powders included a stoichiometric weight ratio of 0.8:0.2. The coatings were characterized by scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, nanoindentation, and conductivity. We report herein that three optimized anode layers of thicknesses between 200 and 300 µm and porosity as high as 20% for Mo-Mo2C/Al2O3 (250-µm thick) and Mo-Mo2C/TiO2 (300 µm thick) and 17% for Mo-Mo2C/ZrO2 (220-µm thick), controllable by a selection of the APS process parameters with no addition of sacrificial pore-forming material. The nanohardness results indicate the upper layers of the coatings have higher values than the subsurface layers in coatings with some effect of the deposition on the substrate. Mo-Mo2C/ZrO2 shows high electrical conductivity.

  7. Ceria-Based Anodes for Next Generation Solid Oxide Fuel Cells

    Science.gov (United States)

    Mirfakhraei, Behzad

    Mixed ionic and electronic conducting materials (MIECs) have been suggested to represent the next generation of solid oxide fuel cell (SOFC) anodes, primarily due to their significantly enhanced active surface area and their tolerance to fuel components. In this thesis, the main focus has been on determining and tuning the physicochemical and electrochemical properties of ceria-based MIECs in the versatile perovskite or fluorite crystal structures. In one direction, BaZr0.1Ce0.7Y0.1 M0.1O3-delta (M = Fe, Ni, Co and Yb) (BZCY-M) perovskites were synthesized using solid-state or wet citric acid combustion methods and the effect of various transition metal dopants on the sintering behavior, crystal structure, chemical stability under CO2 and H 2S, and electrical conductivity, was investigated. BZCY-Ni, synthesized using the wet combustion method, was the best performing anode, giving a polarization resistance (RP) of 0.4 O.cm2 at 800 °C. Scanning electron microscopy and X-ray diffraction analysis showed that this was due to the exsolution of catalytic Ni nanoparticles onto the oxide surface. Evolving from this promising result, the effect of Mo-doped CeO 2 (nCMO) or Ni nanoparticle infiltration into a porous Gd-doped CeO 2 (GDC) anode (in the fluorite structure) was studied. While 3 wt. % Ni infiltration lowered RP by up to 90 %, giving 0.09 O.cm2 at 800 °C and exhibiting a ca. 5 times higher tolerance towards 10 ppm H2, nCMO infiltration enhanced the H2 stability by ca. 3 times, but had no influence on RP. In parallel work, a first-time study of the Ce3+ and Ce 4+ redox process (pseudocapacitance) within GDC anode materials was carried out using cyclic voltammetry (CV) in wet H2 at high temperatures. It was concluded that, at 500-600 °C, the Ce3+/Ce 4+ reaction is diffusion controlled, probably due to O2- transport limitations in the outer 5-10 layers of the GDC particles, giving a very high capacitance of ca. 70 F/g. Increasing the temperature ultimately

  8. Trends in Catalytic Activity for SOFC Anode materials

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Bessler, W. G.

    2008-01-01

    that oxygen spillover, where adsorbed oxygen is a key intermediate, is the dominant reaction pathway under the conditions used in the experiments. In this way the activity is linked directly to the microscopic binding affinities of reaction intermediates, providing a new understanding of the anode reaction...

  9. Design, Operation and Control Modelling of SOFC/GT Hybrid Systems

    OpenAIRE

    Stiller, Christoph

    2006-01-01

    This thesis focuses on modelling-based design, operation and control of solid oxide fuel cell (SOFC) and gas turbine (GT) hybrid systems. Fuel cells are a promising approach to high-efficiency power generation, as they directly convert chemical energy to electric work. High-temperature fuel cells such as the SOFC can be integrated in gas turbine processes, which further increases the electrical efficiency to values up to 70%. However, there are a number of obstacles for safe operation of such...

  10. Analysis and optimization of a tubular SOFC, using nuclear hydrogen as fuel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Daniel G.; Parra, Lazaro R.G.; Fernandez, Carlos R.G., E-mail: dgr@instec.cu [Instituto Superior de Tecnologias y Ciencias Aplicadas, Habana (Cuba). Dept. de Ingenieria Nuclear; Lira, Carlos A.B.O., E-mail: cabol@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2013-07-01

    One of the main areas of hydrogen uses as an energy carrier is in fuel cells of high standards as solid oxide fuel cells (SOFC). The SOFCs are fuel cells operate at high temperatures making them ideal for use in large power systems, suitable for distributed generation of electricity. Optimization and analysis of these electrochemical devices is an area of great current study. The computational fluid dynamics software (CFD) have unique advantages for analyzing the influence of design parameters on the efficiency of fuel cells. This paper presents a SOFC design cell which employ as fuel hydrogen produced by thermochemical water splitting cycle (I-S). There will be done the optimization of the main parameters thermodynamic and electrochemical cell operating to achieve top performance. Also will be estimate the cell efficiency and a production-consumption hydrogen system. (author)

  11. Analysis and optimization of a tubular SOFC, using nuclear hydrogen as fuel

    International Nuclear Information System (INIS)

    Rodriguez, Daniel G.; Parra, Lazaro R.G.; Fernandez, Carlos R.G.; Lira, Carlos A.B.O.

    2013-01-01

    One of the main areas of hydrogen uses as an energy carrier is in fuel cells of high standards as solid oxide fuel cells (SOFC). The SOFCs are fuel cells operate at high temperatures making them ideal for use in large power systems, suitable for distributed generation of electricity. Optimization and analysis of these electrochemical devices is an area of great current study. The computational fluid dynamics software (CFD) have unique advantages for analyzing the influence of design parameters on the efficiency of fuel cells. This paper presents a SOFC design cell which employ as fuel hydrogen produced by thermochemical water splitting cycle (I-S). There will be done the optimization of the main parameters thermodynamic and electrochemical cell operating to achieve top performance. Also will be estimate the cell efficiency and a production-consumption hydrogen system. (author)

  12. Computer Simulations of Composite Electrodes in Solid-Oxide Fuel-Cells

    Energy Technology Data Exchange (ETDEWEB)

    Sunde, Svein

    1999-07-01

    Fuel cells are devices for converting the combined chemical (free) energy of fuels and oxygen (air) directly to electrical energy without relying on the dynamic action of steam heated by reacting fuel-oxygen mixtures, like in steam turbines, or of the reacting gas mixtures themselves, like in gas turbines. The basic rationale for fuel cells is their high efficiencies as compared to indirect-conversion methods. Fuel cells are currently being considered for a number of applications, among them de-centralised power supply. Fuel cells come in five basic types and are usually classified according to the type of electrolyte used, which in turn to a significant degree limits the options for anode and cathode materials. The solid-oxide fuel-cell (SOFC) , with which this thesis is concerned, is thus named after its oxide electrolyte, typically the oxide-ion conducting material yttria-stabilised zirconia (YSZ). While the cathode of an SOFC is often uniform in chemical composition (or at least intended to be), various problems of delamination, cracking etc. associated with the use of metallic anode electrocatalysts led to the development of composite SOFC anodes. Porous anodes consisting of Ni and YSZ particles in roughly 50/50 wt-% mixtures are now almost standard with any SOFC-development programme. The designer of composite SOFC electrodes is faced with at least three, interrelated questions: (1) What will be the optimum microstructure and composition of the composite electrode? (2) If the structure changes during operation, as is often observed, what will be the consequences for the internal losses in the cell? (3) How do we interpret electrochemical and conductivity measurements with regard to structure and composition? It is the primary purpose of this thesis to provide a framework for modelling the electrochemical and transport properties of composite electrodes for SOFC, and to arrive at some new insights that cannot be offered by experiment alone. Emphasis is put on

  13. Characterisation of the Ni/ScYSZ interface in a model solid oxide fuel cell anode

    DEFF Research Database (Denmark)

    Schmidt, Michael Stenbæk; Hansen, Karin Vels; Norrman, Kion

    2008-01-01

    A nickel point electrode setup was used as a model of an SOFC anode on three slightly different electrolytes of zirconia stabilised by co-doping with scandia and yttria. The effect of electrolyte impurities on the electrode polarisation resistance was investigated by correlating electrochemical...... impedance spectroscopy data with time-of-flight secondary ion mass spectrometry, scanning electron microscopy and atomic force microscopy data. A semi-quantitative analysis of the electrolyte surfaces showed that the levels of surface impurities inside the electrode/electrolyte interface in close proximity...

  14. Singler-chamber SOFCs based on gadolinia doped ceria operated on methane and propane; Pilas de combustible de una sola camara, basadas en electrolitos de ceria dopada con gadolinia y operadas con metano y propano

    Energy Technology Data Exchange (ETDEWEB)

    Morales, M.; Roa, J. J.; Capdevila, X. G.; Segarra, M.; Pinol, S.

    2010-07-01

    The main advantages of single-chamber solid oxide fuel cells (SOFCs) respect to dual-chamber SOFCs, are to simplify the device design and to operate in mixtures of hydrocarbon (methane, propane...) and air, with no separation between fuel and oxidant. However, this design requires the use of selective electrodes for the fuel oxidation and the oxidant reduction. In this work, electrolyte-supported SOFCs were fabricated using gadolinia doped ceria (GDC) as the electrolyte, Ni + GDC as the anode and LSC(La{sub 0}.5Sr{sub 0}.5CoO{sub 3}-{delta})-GDC-Ag{sub 2}O as the cathode. The electrical properties of the cell were determined in mixtures of methane + air and propane + air. The influence of temperature, gas composition and total flow rate on the fuel cell performance was investigated. As a result, the power density was strongly increased with increasing temperature, total flow rate and hydrocarbon composition. Under optimized gas compositions and total flow conditions, power densities of 70 and 320 mW/cm{sup 2} operating on propane at a temperature of 600 degree centigrade and methane (795 degree centigrade) were obtained, respectively. (Author)

  15. In situ X-ray Rietveld analysis of Ni-YSZ solid oxide fuel cell anodes during NiO reduction in H2

    International Nuclear Information System (INIS)

    Reyes Rojas, A; Esparza-Ponce, H E; Fuentes, L; Lopez-Ortiz, A; Keer, A; Reyes-Gasga, J

    2005-01-01

    A synthesis and characterization of solid oxide fuel cell (SOFC) anodes of nickel with 8%mol yttrium stabilized zirconia (Ni-YSZ) is presented. Attention was focused on the kinetics and phase composition associated with the transformation of NiO-YSZ to Ni-YSZ. The anodes were prepared with an alternative synthesis method that includes the use of nickel acetylacetonate as an inorganic precursor to obtain a highly porous material after sintering at 1400 deg. C and oxide reduction (NiO-YSZ → Ni-YSZ) at 800 deg. C for 8 h in a tubular reactor furnace using 10% H 2 /N 2 . The obtained material was compressed by unidirectional axial pressing into 1 cm-diameter discs with 15-66 wt% Ni and calcinated from room temperature to 800 deg. C. A heating rate of 1 deg. C min -1 showed the best results to avoid any anode cracking. Their structural and chemical characterization during the isothermal reduction were carried out by in situ time-resolved X-ray diffraction, refined with the Rietveld method (which allowed knowing the kinetic process of the reduction), scanning electron microscopy and X-ray energy dispersive spectroscopy. The results showed the formation of tetragonal YSZ 8%mol in the presence of nickel, a decrement in the unit cell volume of Ni and an increment of Ni in the Ni-YSZ anodes during the temperature reduction. The analysis indicated that the Johnson-Mehl-Avrami equation is unable to provide a good fit to the kinetics of the phase transformation. Instead, an alternative equation is presented

  16. Microstructural studies on degradation of interface between LSM–YSZ cathode and YSZ electrolyte in SOFCs

    DEFF Research Database (Denmark)

    Liu, Yi-Lin; Hagen, Anke; Barfod, Rasmus

    2009-01-01

    The changes in the cathode/electrolyte interface microstructure have been studied on anode-supported technological solid oxide fuel cells (SOFCs) that were subjected to long-term (1500 h) testing at 750 °C under high electrical loading (a current density of 0.75 A/cm2). These cells exhibit...... different cathode degradation rates depending on, among others, the composition of the cathode gas, being significantly smaller in oxygen than in air. FE-SEM and high resolution analytical TEM were applied for characterization of the interface on a submicron- and nano-scale. The interface degradation has...... to decrease further due to the more pronounced formation of insulating zirconate phases that are present locally and preferably in LSM/YSZ electrolyte contact areas. The effects of the cathode gas on the interface degradation are discussed considering the change of oxygen activity at the interface, possible...

  17. Investigation into the effects of trace coal syn gas species on the performance of solid oxide fuel cell anodes, PhD. thesis, Russ College of Engineering and Technology of Ohio University

    Energy Technology Data Exchange (ETDEWEB)

    Trembly, Jason P. [Ohio Univ., Athens, OH (United States). Russ College of Engineering and Technology

    2007-06-01

    Coal is the United States’ most widely used fossil fuel for the production of electric power. Coal’s availability and cost dictates that it will be used for many years to come in the United States for power production. As a result of the environmental impact of burning coal for power production more efficient and environmentally benign power production processes using coal are sought. Solid oxide fuel cells (SOFCs) combined with gasification technologies represent a potential methodology to produce electric power using coal in a much more efficient and cleaner manner. It has been shown in the past that trace species contained in coal, such as sulfur, severely degrade the performance of solid oxide fuel cells rendering them useless. Coal derived syngas cleanup technologies have been developed that efficiently remove sulfur to levels that do not cause any performance losses in solid oxide fuel cells. The ability of these systems to clean other trace species contained in syngas is not known nor is the effect of these trace species on the performance of solid oxide fuel cells. This works presents the thermodynamic and diffusion transport simulations that were combined with experimental testing to evaluate the effects of the trace species on the performance of solid oxide fuel cells. The results show that some trace species contained in coal will interact with the SOFC anode. In addition to the transport and thermodynamic simulations that were completed experimental tests were completed investigating the effect of HCl and AsH3 on the performance of SOFCs.

  18. Lanthanum germanate-based apatites as electrolyte for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D.; Diaz-Carrasco, P.; Ramos-Barrado, J.R. [Departamento de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C. [Departamento de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain)

    2011-02-15

    Germanate apatites with composition La{sub 10-x}Ge{sub 5.5}Al{sub 0.5}O{sub 26.75-3x/2} have been evaluated for the first time as possible electrolytes for solid oxide fuel cells (SOFCs). Different electrode materials have been considered in this study, i.e. manganite, ferrite, nickelates and cobaltite as cathode materials; and NiO-CGO composite and chromium-manganite as anodes. The chemical compatibility and electrochemical performance of these electrodes with La{sub 9.8}Ge{sub 5.5}Al{sub 0.5}O{sub 26.45} have been studied by X-ray powder diffraction (XRPD) and impedance spectroscopy. The XRPD analysis did not reveal appreciable bulk reactivity with the formation of reaction products between the germanate electrolyte and these electrodes up to 1,200 C. However, a significant cation interdiffusion was observed by energy dispersive spectroscopy (EDS) at the electrode/electrolyte interface, which leads to a significant decrease of the performance of these electrodes. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Experimental analysis of performance degradation of micro-tubular solid oxide fuel cells fed by different fuel mixtures

    Science.gov (United States)

    Calise, F.; Restucccia, G.; Sammes, N.

    This paper analyzes the thermodynamic and electrochemical dynamic performance of an anode supported micro-tubular solid oxide fuel cell (SOFC) fed by different types of fuel. The micro-tubular SOFC used is anode supported, consisting of a NiO and Gd 0.2Ce 0.8O 2- x (GDC) cermet anode, thin GDC electrolyte, and a La 0.6Sr 0.4Co 0.2Fe 0.8O 3- y (LSCF) and GDC cermet cathode. The fabrication of the cells under investigation is briefly summarized, with emphasis on the innovations with respect to traditional techniques. Such micro-tubular cells were tested using a Test Stand consisting of: a vertical tubular furnace, an electrical load, a galvanostast, a bubbler, gas pipelines, temperature, pressure and flow meters. The tests on the micro-SOFC were performed using H 2, CO, CH 4 and H 2O in different combinations at 550 °C, to determine the cell polarization curves under several load cycles. Long-term experimental tests were also performed in order to assess degradation of the electrochemical performance of the cell. Results of the tests were analyzed aiming at determining the sources of the cell performance degradation. Authors concluded that the cell under investigation is particularly sensitive to the carbon deposition which significantly reduces cell performance, after few cycles, when fed by light hydrocarbons. A significant performance degradation is also detected when hydrogen is used as fuel. In this case, the authors ascribe the degradation to the micro-cracks, the change in materials crystalline structure and problems with electrical connections.

  20. The integrated project SOFC600 development of low-temperature SOFC

    DEFF Research Database (Denmark)

    Rietveld, B.; Van Berkel, F.; Zhang-Steenwinkel, Y.

    2009-01-01

    The Integrated Project SOFC600 unites 21 partners jointly working on the research and development of SOFC stack components for operation at 600oC. The project is funded by the European Commission within the 6th Framework Programme. Low-temperature operation is considered essential for achieving c...

  1. Operation of real landfill gas fueled solid oxide fuel cell (SOFC) using internal dry reforming

    DEFF Research Database (Denmark)

    Langnickel, Hendrik; Hagen, Anke

    2017-01-01

    Biomass is one renewable energy source, which is independent from solar radiation and wind effect. Solid oxide fuel cells (SOFC’s) are able to convert landfill gas derived from landfill directly into electricity and heat with a high efficiency. In the present work a planar 16cm2 SOFC cell...... was necessary to prevent poisoning and thereby to decrease the degradation rate....

  2. Modeling work of a small scale gasifier/SOFC CHP system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, M.; Aravind, P.V.; Qu, Z.; Woudstra, N.; Verkooijen, A.H.M. [Delft University of Technology (Netherlands). Dept. of Mechanical Engineering], Emails: ming.liu@tudelft.nl, p.v.aravind@tudelft.nl, z.qu@tudelft.nl, n.woudstra@tudelft.nl, a. h. m. verkooijen@tudelft.nl; Cobas, V.R.M. [Federal University of Itajuba (UNIFEI), Pinheirinhos, MG (Brazil). Dept. of Mechanical Engineering], E-mail: vlad@unifei.edu.br

    2009-07-01

    For a highly efficient biomass gasification/Solid Oxide Fuel Cell (SOFC) Combined Heat and Power (CHP) generation system, the gasifier, the accompanying gas cleaning technologies and the CHP unit must be carefully designed as an integrated unit. This paper describes such a system involving a two-stage fixed-bed down draft gasifier, a SOFC CHP unit and a gas cleaning system. A gas cleaning system with both low temperature and high temperature sections is proposed for coupling the gasifier and the SOFC. Thermodynamic modeling was carried out for the gasifier/SOFC system with the proposed gas cleaning system. The net AC electrical efficiency of this system is around 30% and the overall system efficiency is around 60%. This paper also describes various exergy losses in the system and the future plans for integrated gasifier-GCU-SOFC experiments from which the results will be used to validate the modeling results of this system. (author)

  3. Development of a fuel flexible, air-regulated, modular, and electrically integrated SOFC-system (FlameSOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Voss, S.; Trimis, D. [TU Bergakademie Freiberg (Germany). Inst. of Thermal Engineering; Valldorf, J. [VDI/VDE Innovation + Technik GmbH (Germany)

    2010-07-01

    The present paper summarizes experimental results from the operation of the SOFC based micro-CHP unit developed within the framework of the project FlameSOFC. The project is co-financed by the European Commission as an Integrated Project within the 6{sup th} framework program. The objective is the development of an innovative SOFC-based micro-CHP system capable of operating with different gaseous and liquid fuels and fulfilling the technological and market requirements at a European level. The partners involved in the FlameSOFC project bring together a sufficient number of important European actors on the scientific, research and industry level including SMEs and industrial partners from the heating sector. The presented work concerns the operation of the 2{sup nd} phase prototype FlameSOFC system, with a 1 kW{sub el.} SOFC stack and natural gas as feedstock. (orig.)

  4. Modeling and Analysis of Transport Processes and Efficiency of Combined SOFC and PEMFC Systems

    DEFF Research Database (Denmark)

    Rabbani, Raja Abid; Rokni, Masoud

    2014-01-01

    A hybrid fuel cell system (~10 kWe) for an average family house including heating is proposed. The investigated system comprises a Solid Oxide Fuel Cell (SOFC) on top of a Polymer Electrolyte Fuel Cell (PEFC). Hydrogen produced from the off-gases of the SOFC can be fed directly to the PEFC. Simul...

  5. Diesel CPO for SOFC. Development of a cold-flame assisted CPO reactor coupled to a SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Van Dijk, H.A.J.; Ouweltjes, J.P.; Nyqvist, R.G. [ECN Hydrogen and Clean Fossil Fuels, Petten (Netherlands)

    2009-07-15

    Within the research program 'Reforming of liquid fuels for fuel-cells', ECN started a project on the development of a diesel CPO (catalytic partial oxidation) reformer for SOFC (solid oxide fuel cell) in 2005. The application in mind is a small scale (5kWe) diesel fed auxiliary power unit (APU). The goal of the project is to develop the technology required to transform a liquid logistic fuel into a reformat suitable for the operation of a SOFC. The emphasis of this work is on the development of a cold-flame assisted evaporator/mixer coupled to a catalytic CPO reformer. The application of cold-flame evaporation and mixing allows the reformat to be directly fed to the SOFC without further heating or cooling. Moreover, once cold-flames are ignited and stabilized, pre-heating of the air and fuel becomes obsolete. These aspects justify the development described in this report. In the cold-flame evaporator/mixer, the cold-flames are stabilized by means of a recirculation tube. The momentum of the fuel spray of the nozzle induces the required recirculation. The cold flame evaporator/mixer was coupled to a catalytic reformer reactor, transforming the hydrocarbon+air feed into a CO+H2 rich reformate. The reformer was coupled to a SOFC to be able to verify the quality of the reformat obtained with this reformer. The SOFC therefore served as an analysis tool. Characteristically, the reformat was held at 800C all the way towards the SOFC. For this, high temperature flange connections and steel-ceramic expansion connections were successfully applied. It is demonstrated that cold-flame evaporation of liquid fuels is a feasible means of feed preparation for a catalytic reforming reactor. The quality of the resulting reformat is adequate to be fed to the SOFC. The reformat quality, however, decreased with time-on-stream due to fouling of the reformer by carbon-depositions. These carbon-depositions were essentially located on the fuel injector, which is the coldest part

  6. Thermodynamic simulation of biomass gas steam reforming for a solid oxide fuel cell (SOFC system

    Directory of Open Access Journals (Sweden)

    A. Sordi

    2009-12-01

    Full Text Available This paper presents a methodology to simulate a small-scale fuel cell system for power generation using biomass gas as fuel. The methodology encompasses the thermodynamic and electrochemical aspects of a solid oxide fuel cell (SOFC, as well as solves the problem of chemical equilibrium in complex systems. In this case the complex system is the internal reforming of biomass gas to produce hydrogen. The fuel cell input variables are: operational voltage, cell power output, composition of the biomass gas reforming, thermodynamic efficiency, electrochemical efficiency, practical efficiency, the First and Second law efficiencies for the whole system. The chemical compositions, molar flows and temperatures are presented to each point of the system as well as the exergetic efficiency. For a molar water/carbon ratio of 2, the thermodynamic simulation of the biomass gas reforming indicates the maximum hydrogen production at a temperature of 1070 K, which can vary as a function of the biomass gas composition. The comparison with the efficiency of simple gas turbine cycle and regenerative gas turbine cycle shows the superiority of SOFC for the considered electrical power range.

  7. Electrical and stability performance of anode-supported solid oxide fuel cells with strontium- and magnesium-doped lanthanum gallate thin electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Guo Weimin [College of Chemistry, South China University of Technology, Guangzhou 510640, Guangdong (China); Liu Jiang [College of Chemistry, South China University of Technology, Guangzhou 510640, Guangdong (China)], E-mail: jiangliu@scut.edu.cn; Zhang Yaohui [College of Chemistry, South China University of Technology, Guangzhou 510640, Guangdong (China)

    2008-05-20

    Anode-supported solid oxide fuel cells (SOFCs) comprising NiO-samarium-doped ceria (SDC) (Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9}) composite anode, thin tri-layer electrolyte, and La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3} (LSCF)-La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}} (LSGM) composite cathode were fabricated. The thin tri-layer consisting of an 11-{mu}m thick LSGM electrolyte layer and a 12-{mu}m thick La{sub 0.4}Ce{sub 0.6}O{sub 1.8} (LDC) layer on each side of the LSGM was prepared by centrifugal casting and co-firing technique. The performance of the cells operated with humidified H{sub 2} as fuel and ambient air as oxidant showed a maximum power density of 1.23 W cm{sup -2} at 800 deg. C. A stability test of about 100 h was carried out and some deterioration of output power was observed, while the open circuit voltage (OCV) kept unchanged. Impedance measurements showed that both the electrolyte ohmic resistance and the electrode polarization increased with time and the latter dominated the degradation.

  8. Electrically Conductive and Protective Coating for Planar SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jung-Pyung; Stevenson, Jeffry W.

    2017-12-04

    Ferritic stainless steels are preferred interconnect materials for intermediate temperature SOFCs because of their resistance to oxidation, high formability and low cost. However, their protective oxide layer produces Cr-containing volatile species at SOFC operating temperatures and conditions, which can cause cathode poisoning. Electrically conducting spinel coatings have been developed to prevent cathode poisoning and to maintain an electrically conductive pathway through SOFC stacks. However, this coating is not compatible with the formation of stable, hermetic seals between the interconnect frame component and the ceramic cell. Thus, a new aluminizing process has been developed by PNNL to enable durable sealing, prevent Cr evaporation, and maintain electrical insulation between stack repeat units. Hence, two different types of coating need to have stable operation of SOFC stacks. This paper will focus on the electrically conductive coating process. Moreover, an advanced coating process, compatible with a non-electrically conductive coating will be

  9. Modeling and Analysis of Transport Processes and Efficiency of Combined SOFC and PEMFC Systems

    Directory of Open Access Journals (Sweden)

    Abid Rabbani

    2014-08-01

    Full Text Available A hybrid fuel cell system (~10 kWe for an average family house including heating is proposed. The investigated system comprises a Solid Oxide Fuel Cell (SOFC on top of a Polymer Electrolyte Fuel Cell (PEFC. Hydrogen produced from the off-gases of the SOFC can be fed directly to the PEFC. Simulations for the proposed system were conducted using different fuels. Here, results for natural gas (NG, dimethyl ether (DME and ethanol as a fuel are presented and analysed. Behaviour of the proposed system is further investigated by comparing the effects of key factors such as utilisation factor, operating conditions, oxygen-to-carbon (O/C ratios and fuel preheating effects on these fuels. The combined system improves the overall electrical conversion efficiency compared with standalone PEFC or SOFC systems. For the combined SOFC and PEFC system, the overall power production was increased by 8%–16% and the system efficiency with one of the fuels is found to be 12% higher than that of the standalone SOFC system.

  10. Control System Based on Anode Offgas Recycle for Solid Oxide Fuel Cell System

    Directory of Open Access Journals (Sweden)

    Shuanghong Li

    2018-01-01

    Full Text Available The conflicting operation objectives between rapid load following and the fuel depletion avoidance as well as the strong interactions between the thermal and electrical parameters make the SOFC system difficult to control. This study focuses on the design of the decoupling control for the thermal and electrical characteristics of the SOFC system through anode offgas recycling (AOR. The decoupling control system can independently manipulate the thermal and electrical parameters, which interact with one another in most cases, such as stack temperatures, burner temperature, system current, and system power. Under the decoupling control scheme, the AOR is taken as a manipulation variable. The burner controller maintains the burner temperature without being affected by abrupt power change. The stack temperature controller properly coordinates with the burner temperature controller to independently modulate the stack thermal parameters. For the electrical problems, the decoupling control scheme shows its superiority over the conventional controller in alleviating rapid load following and fuel depletion avoidance. System-level simulation under a power-changing case is performed to validate the control freedom between the thermal and electrical characteristics as well as the stability, efficiency, and robustness of the novel system control scheme.

  11. Advanced manufacturing of intermediate temperature, direct methane oxidation membrane electrode assemblies for durable solid oxide fuel cell, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ITN proposes to create an innovative anode supported membrane electrode assembly (MEA) for solid oxide fuel cells (SOFCs) that is capable of long-term operation at...

  12. Parametric exergy analysis of a tubular Solid Oxide Fuel Cell (SOFC) stack through finite-volume model

    International Nuclear Information System (INIS)

    Calise, F.; Ferruzzi, G.; Vanoli, L.

    2009-01-01

    This paper presents a very detailed local exergy analysis of a tubular Solid Oxide Fuel Cell (SOFC) stack. In particular, a complete parametric analysis has been carried out, in order to assess the effects of the synthesis/design parameters on the local irreversibilities in the components of the stack. A finite-volume axial-symmetric model of the tubular internal reforming Solid Oxide Fuel Cell stack under investigation has been used. The stack consists of: SOFC tubes, tube-in-tube pre-reformer and tube and shell catalytic burner. The model takes into account the effects of heat/mass transfer and chemical/electrochemical reactions. The model allows one to predict the performance of a SOFC stack once a series of design and operative parameters are fixed, but also to investigate the source and localization of inefficiency. To this scope, an exergy analysis was implemented. The SOFC tube, the pre-reformer and the catalytic burner are discretized along their longitudinal axes. Detailed models of the kinetics of the reforming, catalytic combustion and electrochemical reactions are implemented. Pressure drops, convection heat transfer and overvoltages are calculated on the basis of the work previously developed by the authors. The heat transfer model includes the contribution of thermal radiation, so improving the models previously used by the authors. Radiative heat transfer is calculated on the basis of the slice-to-slice configuration factors and corresponding radiosities. On the basis of this thermochemical model, an exergy analysis has been carried out, in order to localize the sources and the magnitude of irreversibilities along the components of the stack. In addition, the main synthesis/design variables were varied in order to assess their effect on the exergy destruction within the component to which the parameter directly refers ('endogenous' contribution) and on the exergy destruction of all remaining components ('exogenous' contribution). Then, this analysis

  13. Internal reforming of methane in a mono-block-layer build solid oxide fuel cell with an embedding porous pipe: Numerical analysis

    International Nuclear Information System (INIS)

    Ramírez-Minguela, J.J.; Mendoza-Miranda, J.M.; Muñoz-Carpio, V.D.; Rangel-Hernández, V.H.; Pérez-García, V.; Rodríguez-Muñoz, J.L.

    2014-01-01

    Highlights: • A MOLB-type SOFC with different biogas compositions is modeled. • Internal reforming of methane and water gas shift in the anode side are considered. • Changes in the SOFC according to the phenomena inside of them are assessed. • A new configuration for the MOLB-type geometry is proposed. • Temperature gradients effects in the new configuration are significant. - Abstract: A mono-block-layer build type (MOLB-type) geometry, composed with trapezoidal cross-section channels for fuel and air, of solid oxide fuel cell (SOFC), is modeled in this study using a three dimensional computational fluid dynamics (CFD). The model is used to obtain the performance of the SOFC considering internal reforming of methane in the anode side with different biogas compositions. From the results obtained, a new configuration for the MOLB-type geometry is proposed. The model takes into account the mass transfer, heat transfer, species transport, chemical and electrochemical reactions, detailed comparisons of species concentration, temperature and electric fields inside the cell analyzed in the present study. Results show that the biogas from local sludge has the lower temperature gradient and more homogeneous current density distributions along of the fuel cell, on the other hand, with the new configuration proposed for the MOLB-type geometry the temperature distribution inside of the fuel cell has lower temperature gradients

  14. Modeling of a thermally integrated 10 kWe planar solid oxide fuel cell system with anode offgas recycling and internal reforming by discretization in flow direction

    Science.gov (United States)

    Wahl, Stefanie; Segarra, Ana Gallet; Horstmann, Peter; Carré, Maxime; Bessler, Wolfgang G.; Lapicque, François; Friedrich, K. Andreas

    2015-04-01

    Combined heat and power production (CHP) based on solid oxide fuel cells (SOFC) is a very promising technology to achieve high electrical efficiency to cover power demand by decentralized production. This paper presents a dynamic quasi 2D model of an SOFC system which consists of stack and balance of plant and includes thermal coupling between the single components. The model is implemented in Modelica® and validated with experimental data for the stack UI-characteristic and the thermal behavior. The good agreement between experimental and simulation results demonstrates the validity of the model. Different operating conditions and system configurations are tested, increasing the net electrical efficiency to 57% by implementing an anode offgas recycle rate of 65%. A sensitivity analysis of characteristic values of the system like fuel utilization, oxygen-to-carbon ratio and electrical efficiency for different natural gas compositions is carried out. The result shows that a control strategy adapted to variable natural gas composition and its energy content should be developed in order to optimize the operation of the system.

  15. Hybrid Metal/Electrolyte Monolithic Low Temperature SOFCs

    National Research Council Canada - National Science Library

    Cochran, Joe

    2004-01-01

    The program objective is to develop SOFCs, operating in the 500-700 degrees C range, based on Metal/Electrolyte square cell honeycomb formed by simultaneous powder extrusion of electrolyte and metal...

  16. Integration of a municipal solid waste gasification plant with solid oxide fuel cell and gas turbine

    DEFF Research Database (Denmark)

    Bellomare, Filippo; Rokni, Masoud

    2013-01-01

    An interesting source of producing energy with low pollutants emission and reduced environmental impact are the biomasses; particularly using Municipal Solid Waste (MSW) as fuel, can be a competitive solution not only to produce energy with negligible costs but also to decrease the storage...... in landfills. A Municipal Solid Waste Gasification Plant Integrated with Solid Oxide Fuel Cell (SOFC) and Gas Turbine (GT) has been studied and the plant is called IGSG (Integrated Gasification SOFC and GT). Gasification plant is fed by MSW to produce syngas by which the anode side of an SOFC is fed wherein...

  17. Internal reforming of methane in solid oxide fuel cell systems

    Science.gov (United States)

    Peters, R.; Dahl, R.; Klüttgen, U.; Palm, C.; Stolten, D.

    Internal reforming is an attractive option offering a significant cost reduction, higher efficiencies and faster load response of a solid oxide fuel cell (SOFC) power plant. However, complete internal reforming may lead to several problems which can be avoided with partial pre-reforming of natural gas. In order to achieve high total plant efficiency associated with low energy consumption and low investment costs, a process concept has been developed based on all the components of the SOFC system. In the case of anode gas recycling an internal steam circuit exists. This has the advantage that there is no need for an external steam generator and the steam concentration in the anode gas is reduced. However, anode gas recycling has to be proven by experiments in a pre-reformer and for internal reforming. The addition of carbon dioxide clearly shows a decrease in catalyst activity, while for temperatures higher than 1000 K hydrogen leads to an increase of the measured methane conversion rates.

  18. Co-sintering of CGO/NIO-CGO bilayers for solid oxide fuel cell; Co-sinterizacao de bi-camadas anodo/eletrolito para celulas a combustivel de oxido solido

    Energy Technology Data Exchange (ETDEWEB)

    Neto, P.P.B.; Grilo, J.P.F.; Souza, G.L.; Macedo, D.A.; Paskocimas, C.A.; Nascimento, R.M., E-mail: pbritoneto@gmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2012-07-01

    Reducing the operating temperature of solid oxide fuel cells (SOFC) for the range between 500 and 700°C is one of the challenges which more has aroused the interest of research in SOFC in recent years. In this context, the bilayer anode/electrolyte composed of a porous support based on Ni-doped ceria (anode) and a ceria doped gadolinia (CGO) electrolyte, presents itself as one of the half-cell configurations of the most interest towards the production of electricity in the operating logic of a SOFC. In this work, CGO films were successfully prepared on NiO-CGO substrates using the resources of the screen-printing technique. The bi-layers were co-sintered between 1350 and 1450 ° C for 4 h and then characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS). The results showed good adhesion at the film/substrate interface and no cracks in the films. (author)

  19. The modeling and simulation of thermal based modified solid oxide fuel cell (SOFC for grid-connected systems

    Directory of Open Access Journals (Sweden)

    Ayetül Gelen

    2015-05-01

    Full Text Available This paper presents a thermal based modified dynamic model of a Solid Oxide Fuel Cell (SOFC for grid-connected systems. The proposed fuel cell model involves ohmic, activation and concentration voltage losses, thermal dynamics, methanol reformer, fuel utilization factor and power limiting module. A power conditioning unit (PCU, which consists of a DC-DC boost converter and a DC-AC voltage-source inverter (VSI, their controller, transformer and filter, is designed for grid-connected systems. The voltage-source inverter with six Insulated Gate Bipolar Transistor (IGBT switches inverts the DC voltage that comes from the converter into a sinusoidal voltage synchronized with the grid. The simulations and modeling of the system are developed on Matlab/Simulink environment. The performance of SOFC with converter is examined under step and random load conditions. The simulation results show that the designed boost converter for the proposed thermal based modified SOFC model has fairly followed different DC load variations. Finally, the AC bus of 400 Volt and 50 Hz is connected to a single-machine infinite bus (SMIB through a transmission line. The real and reactive power managements of the inverter are analyzed by an infinite bus system. Thus, the desired nominal values are properly obtained by means of the inverter controller.

  20. Influence of Electrode Design and Contacting Layers on Performance of Electrolyte Supported SOFC/SOEC Single Cells

    Directory of Open Access Journals (Sweden)

    Mihails Kusnezoff

    2016-11-01

    Full Text Available The solid oxide cell is a basis for highly efficient and reversible electrochemical energy conversion. A single cell based on a planar electrolyte substrate as support (ESC is often utilized for SOFC/SOEC stack manufacturing and fulfills necessary requirements for application in small, medium and large scale fuel cell and electrolysis systems. Thickness of the electrolyte substrate, and its ionic conductivity limits the power density of the ESC. To improve the performance of this cell type in SOFC/SOEC mode, alternative fuel electrodes, on the basis of Ni/CGO as well as electrolytes with reduced thickness, have been applied. Furthermore, different interlayers on the air side have been tested to avoid the electrode delamination and to reduce the cell degradation in electrolysis mode. Finally, the influence of the contacting layer on cell performance, especially for cells with an ultrathin electrolyte and thin electrode layers, has been investigated. It has been found that Ni/CGO outperform traditional Ni/8YSZ electrodes and the introduction of a ScSZ interlayer substantially reduces the degradation rate of ESC in electrolysis mode. Furthermore, it was demonstrated that, for thin electrodes, the application of contacting layers with good conductivity and adhesion to current collectors improves performance significantly.

  1. Influence of Electrode Design and Contacting Layers on Performance of Electrolyte Supported SOFC/SOEC Single Cells.

    Science.gov (United States)

    Kusnezoff, Mihails; Trofimenko, Nikolai; Müller, Martin; Michaelis, Alexander

    2016-11-08

    The solid oxide cell is a basis for highly efficient and reversible electrochemical energy conversion. A single cell based on a planar electrolyte substrate as support (ESC) is often utilized for SOFC/SOEC stack manufacturing and fulfills necessary requirements for application in small, medium and large scale fuel cell and electrolysis systems. Thickness of the electrolyte substrate, and its ionic conductivity limits the power density of the ESC. To improve the performance of this cell type in SOFC/SOEC mode, alternative fuel electrodes, on the basis of Ni/CGO as well as electrolytes with reduced thickness, have been applied. Furthermore, different interlayers on the air side have been tested to avoid the electrode delamination and to reduce the cell degradation in electrolysis mode. Finally, the influence of the contacting layer on cell performance, especially for cells with an ultrathin electrolyte and thin electrode layers, has been investigated. It has been found that Ni/CGO outperform traditional Ni/8YSZ electrodes and the introduction of a ScSZ interlayer substantially reduces the degradation rate of ESC in electrolysis mode. Furthermore, it was demonstrated that, for thin electrodes, the application of contacting layers with good conductivity and adhesion to current collectors improves performance significantly.

  2. Probing Temperature Inside Planar SOFC Short Stack, Modules, and Stack Series

    Science.gov (United States)

    Yu, Rong; Guan, Wanbing; Zhou, Xiao-Dong

    2017-02-01

    Probing temperature inside a solid oxide fuel cell (SOFC) stack lies at the heart of the development of high-performance and stable SOFC systems. In this article, we report our recent work on the direct measurements of the temperature in three types of SOFC systems: a 5-cell short stack, a 30-cell stack module, and a stack series consisting of two 30-cell stack modules. The dependence of temperature on the gas flow rate and current density was studied under a current sweep or steady-state operation. During the current sweep, the temperature inside the 5-cell stack decreased with increasing current, while it increased significantly at the bottom and top of the 30-cell stack. During a steady-state operation, the temperature of the 5-cell stack was stable while it was increased in the 30-cell stack. In the stack series, the maximum temperature gradient reached 190°C when the gas was not preheated. If the gas was preheated and the temperature gradient was reduced to 23°C in the stack series with the presence of a preheating gas and segmented temperature control, this resulted in a low degradation rate.

  3. Continued research, development and test of SOFC Technology. Final report

    Energy Technology Data Exchange (ETDEWEB)

    2008-09-15

    The aim of the project was to further develop the SOFC cell and stack technology and drive down manufacturing costs in order to accomplish the performance and economic targets set forward in the SOFC road map, which has been developed in collaboration with the national Danish SOFC Strategy group. The project was divided into four parts. Part 1, Continued cell development covered the successful development of larger cells with a 500 cm2 footprint. Part 2, Cell manufacturing covered the production of 9.859 equivalents (12x12 cm2 standard cells) that were used in the stacks for demonstration projects (EFP 33033-0050)and for in-house research, development and testing in this project. Part 3, Continued stack development covered the successful test of a 3 kW{sub e} stack as well as the planning of a >8.000 hours stack test with new stack technology. The >8.000 hours test that started after the end date for this project will last for 12 months and be reported in the PSO 2008-1-010049 project. Part 4, Stack manufacturing covered a number of small stacks for in-house research, development and testing. (auther)

  4. Cold start dynamics and temperature sliding observer design of an automotive SOFC APU

    Science.gov (United States)

    Lin, Po-Hsu; Hong, Che-Wun

    This paper presents a dynamic model for studying the cold start dynamics and observer design of an auxiliary power unit (APU) for automotive applications. The APU is embedded with a solid oxide fuel cell (SOFC) stack which is a quiet and pollutant-free electric generator; however, it suffers from slow start problem from ambient conditions. The SOFC APU system equips with an after-burner to accelerate the start-up transient in this research. The combustion chamber burns the residual fuel (and air) left from the SOFC to raise the exhaust temperature to preheat the SOFC stack through an energy recovery unit. Since thermal effect is the dominant factor that influences the SOFC transient and steady performance, a nonlinear real-time sliding observer for stack temperature was implemented into the system dynamics to monitor the temperature variation for future controller design. The simulation results show that a 100 W APU system in this research takes about 2 min (in theory) for start-up without considering the thermal limitation of the cell fracture.

  5. Development of Long-Term Stable and High-Performing Metal-Supported SOFCs

    DEFF Research Database (Denmark)

    Klemensø, Trine; Nielsen, Jimmi; Blennow Tullmar, Peter

    2011-01-01

    Metal-supported SOFCs are believed to have high potential for commercialization due to lower material costs and higher robustness in fabrication and operation. However, the development of the cell is challenged by the metal properties during fabrication, and the necessary lower operating temperat......Metal-supported SOFCs are believed to have high potential for commercialization due to lower material costs and higher robustness in fabrication and operation. However, the development of the cell is challenged by the metal properties during fabrication, and the necessary lower operating...... temperatures, while retaining both the energy output and the stability. The metal-supported SOFC design developed at Risø DTU has been optimized to an ASR value of 0.62 cm2 at 650 °C, and a steady degradation rate of 1.0% kh-1 demonstrated for 3000 h on a 16 cm2 active cell level. Additional improvement...

  6. Thermal plasma spraying for SOFCs: Applications, potential advantages, and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Rob; Wang, Zhenwei; Jankovic, Jasna; Yick, Sing; Maric, Radenka; Ghosh, Dave [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Kesler, Olivera [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4 (Canada); Rose, Lars [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Department of Materials Engineering, University of British Columbia, 309-6350 Stores Road, Vancouver, BC V6T 1Z4 (Canada)

    2007-07-10

    In this article, the applications, potential advantages, and challenges of thermal plasma spray (PS) processing for nanopowder production and cell fabrication of solid oxide fuel cells (SOFCs) are reviewed. PS processing creates sufficiently high temperatures to melt all materials fed into the plasma. The heated material can either be quenched into oxide powders or deposited as coatings. This technique has been applied to directly deposit functional layers as well as nanopowder for SOFCs application. In particularly, low melting point and highly active electrodes can be directly fabricated on zirconia-based electrolytes. This is a simple processing technique that does not require the use of organic solvents, offering the opportunity for flexible adjustment of process parameters, and significant time saving in production of the cell and cost reduction compared with tape casting, screen printing and sintering processing steps. Most importantly, PS processing shows strong potential to enable the deposition of metal-supported SOFCs through the integrated fabrication of membrane-electrode assemblies (MEA) on porous metallic substrates with consecutive deposition steps. On the other hand, the application of PS processing to produce SOFCs faces some challenges, such as insufficient porosity of the electrodes, the difficulty of obtaining a thin (<10 {mu}m) and dense electrolyte layer. Fed with H{sub 2} as the fuel gas and oxygen as the oxidant gas, the plasma sprayed cell reached high power densities of 770 mW cm{sup -2} at 900 C and 430 mW cm{sup -2} at 800 C at a cell voltage of 0.7 V. (author)

  7. Direct ethanol solid oxide fuel cell operating in gradual internal reforming

    Science.gov (United States)

    Nobrega, S. D.; Galesco, M. V.; Girona, K.; de Florio, D. Z.; Steil, M. C.; Georges, S.; Fonseca, F. C.

    2012-09-01

    An electrolyte supported solid oxide fuel cell (SOFC) using standard electrodes, doped-lanthanum manganite cathode and Ni-cermet anode, was operated with direct (anhydrous) ethanol for more than 100 h, delivering essentially the same power output as running on hydrogen. A ceria-based layer provides the catalytic activity for the gradual internal reforming, which uses the steam formed by the electrochemical oxidation of hydrogen for the decomposition of ethanol. Such a concept opens up the way for multi-fuel SOFCs using standard components and a catalytic layer.

  8. Kinetic and geometric aspects of solid oxide fuel cell electrodes

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Skaarup, Steen

    1996-01-01

    The paper gives an overview of the main factors controlling the performance of the solid oxide fuel cell (SOFC) electrodes, emphasizing the most widely chosen anodes and cathodes, Ni-YSZ and LSM-YSZ. They are often applied as composites (mixtures) of the electron conducting electrode material...

  9. Conversion of hydrocarbons in solid oxide fuel cells

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Kammer Hansen, K.

    2003-01-01

    Recently, a number of papers about direct oxidation of methane and hydrocarbon in solid oxide fuel cells (SOFC) at relatively low temperatures (about 700degreesC) have been published. Even though the conversion of almost dry CH4 at 1000degreesC on ceramic anodes was demonstrated more than 10 years...

  10. Market orientated design studies for SOFC based systems

    Energy Technology Data Exchange (ETDEWEB)

    Nietsch, T.; Clark, J.

    1999-07-01

    This report examines the development status of Solid Oxide Fuel Cell (SOFC) technology, assesses its commercial potential for heat and power generation in the UK and identifies key development areas for both the SOFC stack and associated system components. A range of Distributed Generation (DG) and Combined Heat and Power (CHP) applications were considered in arriving at these recommendations. The project commenced with initial surveys of leading SOFC technology companies and centres world-wide. These surveys were conducted in parallel with consultations with key operator organisations in the UK which enabled the requirements of these organisations within the UK Energy Supply Industry to be identified. As a result of the initial survey, over 30 fuel cell based power plants, of size ranging from 1 kW{sub e} to 20 MW{sub e} for both DG and CHP applications, were identified. Outline designs of these applications were then set up and simulated. These candidate systems were then assessed against each other in terms of efficiency, cost of electricity, specific costs, technical risk and market potential for the UK industry. The final ranking obtained was then confirmed with the key operator organisations. On the basis of the ranking process noted above, nine SOFC based power generation/CHP applications were chosen for more detailed investigation in terms of their potential in both UK and overseas markets. Detailed simulations were conducted for each application to allow study of: the influence of efficiency on the economics of the different plants/stacks; the combination of stack and Balance of Plant (BoP) costs; and the cost and availability of key balance of plant devices. These systems were then again assessed in terms of the criteria noted for the outline stage. Finally key development areas for both SOFC stacks and associated Balance of Plant devices were identified. (author)

  11. Influence of Electrode Design and Contacting Layers on Performance of Electrolyte Supported SOFC/SOEC Single Cells

    OpenAIRE

    Mihails Kusnezoff; Nikolai Trofimenko; Martin Müller; Alexander Michaelis

    2016-01-01

    The solid oxide cell is a basis for highly efficient and reversible electrochemical energy conversion. A single cell based on a planar electrolyte substrate as support (ESC) is often utilized for SOFC/SOEC stack manufacturing and fulfills necessary requirements for application in small, medium and large scale fuel cell and electrolysis systems. Thickness of the electrolyte substrate, and its ionic conductivity limits the power density of the ESC. To improve the performance of this cell type i...

  12. Assessment of full ceramic solid oxide fuel cells based on modified strontium titanates

    DEFF Research Database (Denmark)

    Holtappels, Peter; Ramos, Tania; Sudireddy, Bhaskar Reddy

    2014-01-01

    stimulated the development for full ceramic anodes based on strontium titanates. Furthermore, the Ni-cermet is primarily a hydrogen oxidation electrode and efficiency losses might occur when operating on carbon containing fuels. In the European project SCOTAS-SOFC full ceramic cells comprising CGO...

  13. Development of 10kW SOFC module

    Energy Technology Data Exchange (ETDEWEB)

    Hisatome, N.; Nagata, K. [Mitsubishi Heavy Industries, Ltd., Nagasaki (Japan); Kakigami, S. [Electric Power Development Co., Inc., Tokyo (Japan)] [and others

    1996-12-31

    Mitsubishi Heavy industries, Ltd. (MHI) has been developing tubular type Solid Oxide Fuel Cells (SOFC) since 1984. A 1 kW module of SOFC has been continuously operated for 3,000 hours with 2 scheduled thermal cycles at Electric Power Development Co., Inc. (EPDC) Wakamatsu Power Station in 1993. We have obtained of 34% (HHV as H{sub 2}) module efficiency and deterioration rate of 2% Per 1,000 hours in this field test. As for next step, we have developed 10 kW module in 1995. The 10 kW module has been operated for 5,000 hours continuously. This module does not need heating support to maintain the operation temperature, and the module efficiency was 34% (HHV as H{sub 2}). On the other hand, we have started developing the technology of pressurized SOFC. In 1996, pressurized MW module has been tested at MHI Nagasaki Shipyard & Machinery, Works. We are now planning the development of pressurized 10 kW module.

  14. Measurement of residual stresses in deposited films of SOFC component materials

    Energy Technology Data Exchange (ETDEWEB)

    Kato, T.; Momma, A.; Nagata, S.; Kasuga, Y. [Electrotechnical Lab., Ibaraki (Japan)

    1996-12-31

    The stress induced in Solid oxide fuel cells (SOFC)s has important influence on the lifetime of SOFC. But the data on stress in SOFC and mechanical properties of SOW component materials have not been accumulated enough to manufacture SOFC. Especially, the data of La{sub 1-x}Sr{sub x}MnO{sub 3} cathode and La{sub 1-x}Sr{sub x}CrO{sub 3} interconnection have been extremely limited. We have estimated numerically the dependences of residual stress in SOFC on the material properties, the cell structure and the fabrication temperatures of the components, but these unknown factors have caused obstruction to simulate the accurate behavior of residual stress. Therefore, the residual stresses in deposited La{sub 1-x}Sr{sub x}MnO{sub 3} and La{sub 1-x}Sr{sub x}CrO{sub 3} films are researched by the observation of the bending behavior of the substrate strips. The films of SOFC component materials were prepared by the RF sputtering method, because: (1) It can fabricate dense films of poor sinterable material such as La{sub 1-x}Sr{sub x}CrO{sub 3} compared with sintering or plasma spray method. (2) For the complicated material such as perovskite materials, the difference between the composition of a film and that of a target material is generally small. (3) It can fabricate a thick ceramics film by improving of the deposition rate. For example, Al{sub 2}O{sub 3} thick films of 50{mu}m can be fabricated with the deposition rate of approximately 5{mu}m/h industrially. In this paper, the dependence of residual stress on the deposition conditions is defined and mechanical properties of these materials are estimated from the results of the experiments.

  15. Thermodynamic and thermoeconomic analysis of a system with biomass gasification, solid oxide fuel cell (SOFC) and Stirling engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    Thermodynamic and thermoeconomic investigations of a small-scale integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120kWe have been performed. Woodchips are used as gasification feedstock to produce syngas......Wh. Furthermore, hot water is considered as a by-product, and the cost of hot water is found to be 0.0214$/kWh. When compared to other renewable systems of similar scales, this result shows that if both SOFC and Stirling engine technology enter the commercialization phase, then they can deliver electricity...

  16. Performance analysis of a co-generation system using solar energy and SOFC technology

    International Nuclear Information System (INIS)

    Akikur, R.K.; Saidur, R.; Ping, H.W.; Ullah, K.R.

    2014-01-01

    Highlights: • A new concept of a cogeneration system is proposed and investigated. • The system comprises solar collector, PV, SOFC and heat exchanger. • 83.6% Power and heat generation efficiency has been found at fuel cell mode. • 85.1% Efficiency of SOSE has been found at H2 production mode. • The heat to power ratio of SOFC mode has been found about 0.917. - Abstract: Due to the increasing future energy demands and global warming, the renewable alternative energy sources and the efficient power systems have been getting importance over the last few decades. Among the renewable energy technologies, the solar energy coupling with fuel cell technology will be the promising possibilities for the future green energy solutions. Fuel cell cogeneration is an auspicious technology that can potentially reduce the energy consumption and environmental impact associated with serving building electrical and thermal demands. In this study, performance assessment of a co-generation system is presented to deliver electrical and thermal energy using the solar energy and the reversible solid oxide fuel cell. A mathematical model of the co-generation system is developed. To illustrate the performance, the system is considered in three operation modes: a solar-solid oxide fuel cell (SOFC) mode, which is low solar radiation time when the solar photovoltaic (PV) and SOFC are used for electric and heat load supply; a solar-solid oxide steam electrolyzer (SOSE) mode, which is high solar radiation time when PV is used for power supply to the electrical load and to the steam electrolyzer to generate hydrogen (H 2 ); and a SOFC mode, which is the power and heat generation mode of reversible SOFC using the storage H 2 at night time. Also the effects of solar radiation on the system performances and the effects of temperature on RSOFC are analyzed. In this study, 100 kW electric loads are considered and analyzed for the power and heat generation in those three modes to evaluate

  17. Progress in Electrolyte-Free Fuel Cells

    International Nuclear Information System (INIS)

    Lu, Yuzheng; Zhu, Bin; Cai, Yixiao; Kim, Jung-Sik; Wang, Baoyuan; Wang, Jun; Zhang, Yaoming; Li, Junjiao

    2016-01-01

    Solid oxide fuel cell (SOFC) represents a clean electrochemical energy conversion technology with characteristics of high conversion efficiency and low emissions. It is one of the most important new energy technologies in the future. However, the manufacture of SOFCs based on the structure of anode/electrolyte/cathode is complicated and time-consuming. Thus, the cost for the entire fabrication and technology is too high to be affordable, and challenges still hinder commercialization. Recently, a novel type of electrolyte-free fuel cell (EFFC) with single component was invented, which could be the potential candidate for the next generation of advanced fuel cells. This paper briefly introduces the EFFC, working principle, performance, and advantages with updated research progress. A number of key R&D issues about EFFCs have been addressed, and future opportunities and challenges are discussed.

  18. Progress in Electrolyte-Free Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yuzheng [Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology, School of Energy and Environment, Southeast University, Nanjing (China); Zhu, Bin, E-mail: binzhu@kth.se [Faculty of Physics and Electronic Technology, Hubei Collaborative Innovation Center for Advanced Organic Materials, Hubei University, Wuhan (China); Department of Energy Technology, Royal Institute of Technology KTH, Stockholm (Sweden); Cai, Yixiao [Ångström Laboratory, Department of Engineering Sciences, Uppsala University, Uppsala (Sweden); Kim, Jung-Sik [Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough (United Kingdom); Wang, Baoyuan [Faculty of Physics and Electronic Technology, Hubei Collaborative Innovation Center for Advanced Organic Materials, Hubei University, Wuhan (China); Department of Energy Technology, Royal Institute of Technology KTH, Stockholm (Sweden); Wang, Jun, E-mail: binzhu@kth.se; Zhang, Yaoming [Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology, School of Energy and Environment, Southeast University, Nanjing (China); Li, Junjiao [Nanjing Yunna Nano Technology Co., Ltd., Nanjing (China)

    2016-05-02

    Solid oxide fuel cell (SOFC) represents a clean electrochemical energy conversion technology with characteristics of high conversion efficiency and low emissions. It is one of the most important new energy technologies in the future. However, the manufacture of SOFCs based on the structure of anode/electrolyte/cathode is complicated and time-consuming. Thus, the cost for the entire fabrication and technology is too high to be affordable, and challenges still hinder commercialization. Recently, a novel type of electrolyte-free fuel cell (EFFC) with single component was invented, which could be the potential candidate for the next generation of advanced fuel cells. This paper briefly introduces the EFFC, working principle, performance, and advantages with updated research progress. A number of key R&D issues about EFFCs have been addressed, and future opportunities and challenges are discussed.

  19. Behavior of strontium- and magnesium-doped gallate electrolyte in direct carbon solid oxide fuel cells

    International Nuclear Information System (INIS)

    Zhang, Li; Xiao, Jie; Xie, Yongmin; Tang, Yubao; Liu, Jiang; Liu, Meilin

    2014-01-01

    Highlights: • La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3−δ (LSGM) can be used as electrolyte of direct carbon SOFCs. • DC-SOFC with LSGM electrolyte gives higher performance than that with YSZ. • LSGM-electrolyte DC-SOFC gives maximum power density of 383 mW cm −2 at 850 °C. • Operation of LSGM-DC-SOFC at 210 mA cm −2 lasts 72 min, with fuel utilization of 60%. - Abstract: Perovskite-type La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3−δ (LSGM) is synthesized by conventional solid state reaction. Its phase composition, microstructure, relative density, and oxygen-ionic conductivity are investigated. Tubular electrolyte-supported solid oxide fuel cells (SOFCs) are prepared with the LSGM as electrolyte and gadolinia doped ceria (GDC) mixed with silver as anode. The SOFCs are operated with Fe-loaded activated carbon as fuel and ambient air as oxidant. A typical single cell gives a maximum power density of 383 mW cm −2 at 850 °C, which is nearly 1.3 times higher than that of the similar cell with YSZ as electrolyte. A stability test of 72 min is carried out at a constant current density of 210 mA cm −2 , with a fuel utilization of 60%, indicating that LaGaO 3 -based electrolyte is promising to be applied in direct carbon SOFCs (DC-SOFCs)

  20. Electrode Reaction Pathway in Oxide Anode for Solid Oxide Fuel Cells

    Science.gov (United States)

    Li, Wenyuan

    Oxide anodes for solid oxide fuel cells (SOFC) with the advantage of fuel flexibility, resistance to coarsening, small chemical expansion and etc. have been attracting increasing interest. Good performance has been reported with a few of perovskite structure anodes, such as (LaSr)(CrMn)O3. However, more improvements need to be made before meeting the application requirement. Understanding the oxidation mechanism is crucial for a directed optimization, but it is still on the early stage of investigation. In this study, reaction mechanism of oxide anodes is investigated on doped YCrO 3 with H2 fuel, in terms of the origin of electrochemical activity, rate-determining steps (RDS), extension of reactive zone, and the impact from overpotential under service condition to those properties. H2 oxidation on the YCs anodes is found to be limited by charge transfer and H surface diffusion. A model is presented to describe the elementary steps in H2 oxidation. From the reaction order results, it is suggested that any models without taking H into the charge transfer step are invalid. The nature of B site element determines the H2 oxidation kinetics primarily. Ni displays better adsorption ability than Co. However, H adsorption ability of such oxide anode is inferior to that of Ni metal anode. In addition, the charge transfer step is directly associated with the activity of electrons in the anode; therefore it can be significantly promoted by enhancement of the electron activity. It is found that A site Ca doping improves the polarization resistance about 10 times, by increasing the activity of electrons to promote the charge transfer process. For the active area in the oxide anode, besides the traditional three-phase boundary (3PB), the internal anode surface as two-phase boundary (2PB) is proven to be capable of catalytically oxidizing the H2 fuel also when the bulk lattice is activated depending on the B site elements. The contribution from each part is estimated by switching

  1. Mathematical Modeling Analysis and Optimization of Key Design Parameters of Proton-Conductive Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Hong Liu

    2014-01-01

    Full Text Available A proton-conductive solid oxide fuel cell (H-SOFC has the advantage of operating at higher temperatures than a PEM fuel cell, but at lower temperatures than a SOFC. This study proposes a mathematical model for an H-SOFC in order to simulate the performance and optimize the flow channel designs. The model analyzes the average mass transfer and species’ concentrations in flow channels, which allows the determination of an average concentration polarization in anode and cathode gas channels, the proton conductivity of electrolyte membranes, as well as the activation polarization. An electrical circuit for the current and proton conduction is applied to analyze the ohmic losses from an anode current collector to a cathode current collector. The model uses relatively less amount of computational time to find the V-I curve of the fuel cell, and thus it can be applied to compute a large amount of cases with different flow channel dimensions and operating parameters for optimization. The modeling simulation results agreed satisfactorily with the experimental results from literature. Simulation results showed that a relatively small total width of flow channel and rib, together with a small ratio of the rib’s width versus the total width, are preferable for obtaining high power densities and thus high efficiency.

  2. Electrode materials: a challenge for the exploitation of protonic solid oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Emiliana Fabbri, Daniele Pergolesi and Enrico Traversa

    2010-01-01

    Full Text Available High temperature proton conductor (HTPC oxides are attracting extensive attention as electrolyte materials alternative to oxygen-ion conductors for use in solid oxide fuel cells (SOFCs operating at intermediate temperatures (400–700 °C. The need to lower the operating temperature is dictated by cost reduction for SOFC pervasive use. The major stake for the deployment of this technology is the availability of electrodes able to limit polarization losses at the reduced operation temperature. This review aims to comprehensively describe the state-of-the-art anode and cathode materials that have so far been tested with HTPC oxide electrolytes, offering guidelines and possible strategies to speed up the development of protonic SOFCs.

  3. Electrode materials: a challenge for the exploitation of protonic solid oxide fuel cells

    International Nuclear Information System (INIS)

    Fabbri, Emiliana; Pergolesi, Daniele; Traversa, Enrico

    2010-01-01

    High temperature proton conductor (HTPC) oxides are attracting extensive attention as electrolyte materials alternative to oxygen-ion conductors for use in solid oxide fuel cells (SOFCs) operating at intermediate temperatures (400-700 0 C). The need to lower the operating temperature is dictated by cost reduction for SOFC pervasive use. The major stake for the deployment of this technology is the availability of electrodes able to limit polarization losses at the reduced operation temperature. This review aims to comprehensively describe the state-of-the-art anode and cathode materials that have so far been tested with HTPC oxide electrolytes, offering guidelines and possible strategies to speed up the development of protonic SOFCs. (topical review)

  4. Solid oxide cell R&D at Riso National Laboratory-and its transfer to technology

    DEFF Research Database (Denmark)

    Linderoth, Søren

    2009-01-01

    Risø National Laboratory has conducted R&D on solid oxide cells for almost 20 years—all the time together with industries with interest in deploying the technology when mature. Risø National Laboratory (Risø) and Topsoe Fuel Cell A/S (TOFC) have for several years jointly carried out a development...... programme focusing on low cost manufacturing of flat planar anode-supported cells and stacks employing metallic interconnects. The consortium of Risø and TOFC has up-scaled its production capacity of anode-supported cells to about 1,100 per week. New generations of SOFCs are being developed...

  5. Strontium Titanate-based Composite Anodes for Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Kammer Hansen, Kent; Wallenberg, L.R.

    2008-01-01

    Surfactant-assisted infiltration of Gd-doped ceria (CGO) in Nb-doped SrTiO3 (STN) was investigated as a potential fuel electrode for solid oxide fuel cells (SOFC). An electronically conductive backbone structure of STN was first fabricated at high temperatures and then combined with the mixed con...

  6. Solid Oxide Fuel Cell Development at Topsoe Fuel Cell A/S and Risø National Laboratory

    DEFF Research Database (Denmark)

    Christiansen, Niels; Hansen, J B.; Larsen, H H.

    2007-01-01

    The consortium of Topsoe Fuel Cell A/S and Riso National Laboratory has up-scaled its production capacity of anode-supported cells to about 1100 per week. Stacks are based on a compact thin plate multilayer design with metallic interconnects and 12x12 cm(2) or 18x18 cm(2) foot print. Larger (500 ...... to include ethanol and coal syngas by development of a new coke resistant catalyst suitable for future SOFC technology....

  7. Study of variables for accelerating lifetime testing of SOFCs

    DEFF Research Database (Denmark)

    Ploner, Alexandra; Hagen, Anke; Hauch, Anne

    Solid oxide fuel cell (SOFC) applications require lifetimes of several years on the system level. A big challenge is to proof/confirm/demonstrate such exceptionally long lifetimes.Accelerated or compressed testing are possible methods. Activities in this area have been carried out without arriving...... at different current load cycling profiles revealed a strong deviation between predicted and measured lifetime [3].In this study, we present a detailed analysis of durability results for degradation mechanisms of single SOFC components as function of operating conditions. Electrochemical impedance data...

  8. Progress in Electrolyte-Free Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yuzheng eLu

    2016-05-01

    Full Text Available Solid Oxide Fuel Cell (SOFC represents a clean electrochemical energy conversion technology with characteristics of high conversion efficiency and low emissions. It is one of the most important new energy technologies in the future. However, the manufacture of SOFCs based on the structure of anode/electrolyte/cathode is complicated and time-consuming. Thus, the cost for the entire fabrication and technology is too high to be affordable and challenges still hinder commercialization. Recently, a novel type of Electrolyte -free fuel cell (EFFC with single component was invented which could be the potential candidate for the next generation of advanced fuel cells. This paper briefly introduces the EFFC, working principle, performance and advantages with updated research progress. A number of key R&D issues about EFFCs have been addressed and future opportunities and challenges are discussed.

  9. Pre-reforming of natural gas in solid oxide fuel-cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Peters, R.; Riensche, E.; Cremer, P. [Institute for Materials and Processes Systems IWV 3: Energy Process Engineering, Forschungszentrum Juelich (Germany)

    2000-03-01

    Several measures concerning fuel processing in a solid oxide fuel cell (SOFC) system offer the possibility of significant cost reduction and higher system efficiencies. For SOFC systems, the ratio between internal and pre-reforming has to be optimized on the basis of experimental performance data. Furthermore, anode gas recycling by an injector in front of the pre-reformer can eliminate the steam generator and the corresponding heat of evaporation. A detailed study is carried out on pre-reforming in a reformer of considerable size (10 kW{sub el}). Simulating anode gas recycling with an injector, the influence of carbon dioxide on reactor performance was studied. Also, the dependence of the methanol conversion on mass flow and temperature will be discussed. In addition, some results concerning the dynamic behaviour of the pre-reformer are given. (orig.)

  10. Operating Point Optimization of a Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Steam Turbine (SOFC-ST Plant

    Directory of Open Access Journals (Sweden)

    Juanjo Ugartemendia

    2013-09-01

    Full Text Available This paper presents a hydrogen powered hybrid solid oxide fuel cell-steam turbine (SOFC-ST system and studies its optimal operating conditions. This type of installation can be very appropriate to complement the intermittent generation of renewable energies, such as wind generation. A dynamic model of an alternative hybrid SOFC-ST configuration that is especially suited to work with hydrogen is developed. The proposed system recuperates the waste heat of the high temperature fuel cell, to feed a bottoming cycle (BC based on a steam turbine (ST. In order to optimize the behavior and performance of the system, a two-level control structure is proposed. Two controllers have been implemented for the stack temperature and fuel utilization factor. An upper supervisor generates optimal set-points in order to reach a maximal hydrogen efficiency. The simulation results obtained show that the proposed system allows one to reach high efficiencies at rated power levels.

  11. Investigation of aluminosilicate refractory for solid oxide fuel cell applications

    Science.gov (United States)

    Gentile, Paul Steven

    Stationary solid oxide fuel cells (SOFCs) have been demonstrated to provide clean and reliable electricity through electro-chemical conversion of various fuel sources (CH4 and other light hydrocarbons). To become a competitive conversion technology the costs of SOFCs must be reduced to less than $400/kW. Aluminosilicate represents a potential low cost alternative to high purity alumina for SOFC refractory applications. The objectives of this investigation are to: (1) study changes of aluminosilicate chemistry and morphology under SOFC conditions, (2) identify volatile silicon species released by aluminosilicates, (3) identify the mechanisms of aluminosilicate vapor deposition on SOFC materials, and (4) determine the effects of aluminosilicate vapors on SOFC electrochemical performance. It is shown thermodynamically and empirically that low cost aluminosilicate refractory remains chemically and thermally unstable under SOFC operating conditions between 800°C and 1000°C. Energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) of the aluminosilicate bulk and surface identified increased concentrations of silicon at the surface after exposure to SOFC gases at 1000°C for 100 hours. The presence of water vapor accelerated surface diffusion of silicon, creating a more uniform distribution. Thermodynamic equilibrium modeling showed aluminosilicate remains stable in dry air, but the introduction of water vapor indicative of actual SOFC gas streams creates low temperature (active anode interface.

  12. Plant characteristics of an integrated solid oxide fuel cell cycle and a steam cycle

    International Nuclear Information System (INIS)

    Rokni, Masoud

    2010-01-01

    Plant characteristics of a system containing a solid oxide fuel cell (SOFC) cycle on the top of a Rankine cycle were investigated. A desulfurization reactor removes the sulfur content in the fuel, while a pre-reformer broke down the heavier hydrocarbons in an adiabatic steam reformer (ASR). The pre-treated fuel then entered to the anode side of the SOFC. The remaining fuels after the SOFC stacks entered a catalytic burner for further combusting. The burned gases from the burner were then used to produce steam for the Rankine cycle in a heat recovery steam generator (HRSG). The remaining energy of the off-gases was recycled back to the topping cycle for further utilization. Several parameter studies were carried out to investigate the sensitivity of the suggested plant. It was shown that the operation temperature of the desulfurization and the pre-reformer had no effect on the plant efficiency, which was also true when decreasing the anode temperature. However, increasing the cathode temperature had a significant effect on the plant efficiency. In addition, decreasing the SOFC utilization factor from 0.8 to 0.7, increases the plant efficiency by about 6%. An optimal plant efficiency of about 71% was achieved by optimizing the plant.

  13. Plant characteristics of an integrated solid oxide fuel cell cycle and a steam cycle

    Energy Technology Data Exchange (ETDEWEB)

    Rokni, Masoud [Technical University of Denmark, Dept. of Mechanical Engineering, Thermal Energy System, Building 402, 2800 Kgs, Lyngby (Denmark)

    2010-12-15

    Plant characteristics of a system containing a solid oxide fuel cell (SOFC) cycle on the top of a Rankine cycle were investigated. A desulfurization reactor removes the sulfur content in the fuel, while a pre-reformer broke down the heavier hydrocarbons in an adiabatic steam reformer (ASR). The pre-treated fuel then entered to the anode side of the SOFC. The remaining fuels after the SOFC stacks entered a catalytic burner for further combusting. The burned gases from the burner were then used to produce steam for the Rankine cycle in a heat recovery steam generator (HRSG). The remaining energy of the off-gases was recycled back to the topping cycle for further utilization. Several parameter studies were carried out to investigate the sensitivity of the suggested plant. It was shown that the operation temperature of the desulfurization and the pre-reformer had no effect on the plant efficiency, which was also true when decreasing the anode temperature. However, increasing the cathode temperature had a significant effect on the plant efficiency. In addition, decreasing the SOFC utilization factor from 0.8 to 0.7, increases the plant efficiency by about 6%. An optimal plant efficiency of about 71% was achieved by optimizing the plant. (author)

  14. Discrete modelling of the electrochemical performance of SOFC electrodes

    International Nuclear Information System (INIS)

    Schneider, L.C.R.; Martin, C.L.; Bultel, Y.; Bouvard, D.; Siebert, E.

    2006-01-01

    The composite anode and cathode of solid oxide fuel cells (SOFC) are modelled as sintered mixtures of electrolyte and electrocatalyst particles. A particle packing is first created numerically by the discrete element method (DEM) from a loose packing of 40 000 spherical, monosized, homogeneously mixed, and randomly positioned particles. Once the microstructure is sintered numerically, the effective electrode conductivity is determined by discretization of the particle packing into a resistance network. Each particle contact is characteristic of a bond resistance that depends on contact geometry and particle properties. The network, which typically consists of 120 000 bond resistances in total, is solved using Kirchhoff's current law. Distributions of local current densities and particle potentials are then performed. We investigate how electrode performance depends on parameters such as electrode composition, thickness, density and intrinsic material conductivities that are temperature dependent. The simulations show that the best electrode performance is obtained for compositions close to the percolation threshold of the electronic conductor. Depending on particle conductivities, the electrode performance is a function of its thickness. Additionally, DEM simulations generate useful microstructural information such as: coordination numbers, triple phase boundary length and percolation thresholds

  15. Recent Progress in Development and Manufacturing of SOFC at Topsoe Fuel Cell A/S and Risø DTU

    DEFF Research Database (Denmark)

    Christiansen, Niels; Holm-Larsen, Helge; Primdahl, Søren

    2011-01-01

    effort is directed towards improvement of current generations as well as development of the next generation SOFC technology. The innovative concept of the next generation, aiming at improved reliability and robustness, is based on metal-supported cells and nano-structured electrodes with perspectives...

  16. Behavior of strontium- and magnesium-doped gallate electrolyte in direct carbon solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Li; Xiao, Jie; Xie, Yongmin [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Tang, Yubao [Key Laboratory of Sensor Analysis of Tumor Marker Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao o 266042 (China); Liu, Jiang, E-mail: jiangliu@scut.edu.cn [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); New Energy Research Institute, College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); Liu, Meilin [New Energy Research Institute, College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA 30332-0245 (United States)

    2014-09-01

    Highlights: • La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3−δ} (LSGM) can be used as electrolyte of direct carbon SOFCs. • DC-SOFC with LSGM electrolyte gives higher performance than that with YSZ. • LSGM-electrolyte DC-SOFC gives maximum power density of 383 mW cm{sup −2} at 850 °C. • Operation of LSGM-DC-SOFC at 210 mA cm{sup −2} lasts 72 min, with fuel utilization of 60%. - Abstract: Perovskite-type La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3−δ} (LSGM) is synthesized by conventional solid state reaction. Its phase composition, microstructure, relative density, and oxygen-ionic conductivity are investigated. Tubular electrolyte-supported solid oxide fuel cells (SOFCs) are prepared with the LSGM as electrolyte and gadolinia doped ceria (GDC) mixed with silver as anode. The SOFCs are operated with Fe-loaded activated carbon as fuel and ambient air as oxidant. A typical single cell gives a maximum power density of 383 mW cm{sup −2} at 850 °C, which is nearly 1.3 times higher than that of the similar cell with YSZ as electrolyte. A stability test of 72 min is carried out at a constant current density of 210 mA cm{sup −2}, with a fuel utilization of 60%, indicating that LaGaO{sub 3}-based electrolyte is promising to be applied in direct carbon SOFCs (DC-SOFCs)

  17. Studies on Perovskite-Based Electrodes for Symmetrical SOFCs

    Directory of Open Access Journals (Sweden)

    Dos Santos García, A. J.

    2008-10-01

    Full Text Available The use of the same material as anode and cathode in symmetrical solid oxide fuel cells (SFCs promises notable benefits as easier fabrication, hence lower cost production and resistance to carbon formation upon fuel cracking. Although chromites and chromo-manganites have been proposed as candidate electrode materials for this novel SOFC configuration, demonstrating promising performances, further work is required to develop compositions exhibiting higher efficiencies. In the present work we evaluate the structural evolution from cubic to orthorhombic unit cells with increasing the Fe content and the performance of La4Sr8Ti12-xFexO38-δ (LSTF phases and compare their response with other symmetrical electrodes. The electrochemical performance is 20% higher when using graded LSTF electrodes than in other perovskite-based systems.

    La utilización simultánea de un mismo material cerámico como ánodo y cátodo en pilas de combustible de óxido sólido simétricas (SFCs aporta una serie de beneficios entre los que figura una fabricación más sencilla, reducción de los costes de producción, así como resistencia a la formación de depósitos de carbón por craqueo del combustible. Recientemente, cromitas y cromomanganitas han sido propuestos como materiales capaces de adoptar esta novedosa configuración SOFC y, si bien los resultados obtenidos son prometedores, se requiere de una mayor investigación para el desarrollo de nuevas composiciones que presenten eficiencias más elevadas. En el presente trabajo, se evalúan la evolución de la estructura desde celdas cúbicas a ortorrómbicas al aumentar el contenido en Fe y las prestaciones del sistema La4Sr8Ti12-xFexO38-δ (LSTF y se compara su respuesta con otros electrodos simétricos, observándose que el rendimiento es hasta un 20% mayor en el caso de emplear electrodos LSTF que en

  18. Anode Supported Solid Oxide Fuel Cells - Deconvolution of Degradation into Cathode and Anode Contributions

    DEFF Research Database (Denmark)

    Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus

    2007-01-01

    The degradation of anode supported cells was studied over 1500 h as function of cell polarization either in air or oxygen on the cathode. Based on impedance analysis, contributions of anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rates...... of the cathode were strongly dependent on the pO(2); they were significantly smaller when testing in oxygen compared to air. Microstructural analysis of the cathode/electrolyte interface of a not-tested reference cell carried out after removal of the cathode showed sharp craters on the electrolyte surface where...

  19. Thermodynamic Analysis of an Integrated Gasification Solid Oxide Fuel Cell Plant with a Kalina Cycle

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Rokni, Masoud

    2015-01-01

    % is achieved; plant size and nominal power are selected based on the required cultivation area. SOFC heat recovery with SKC is compared to a Steam Cycle (SC). Although ammonia-water more accurately fits the temperature profile of the off-gases, the presence of a Hybrid Recuperator enhances the available work......-treated fuel then enters the anode side of the SOFC. Complete fuel oxidation is ensured in a burner by off-gases exiting the SOFC stacks. Off-gases are utilized as heat source for a SKC where a mixture of ammonia and water is expanded in a turbine to produce additional electric power. Thus, a triple novel......A hybrid plant that consists of a gasification system, Solid Oxide Fuel Cells (SOFC) and a Simple Kalina Cycle (SKC) is investigated. Woodchips are introduced into a fixed bed gasification plant to produce syngas, which is then fed into an integrated SOFC-SKC plant to produce electricity. The pre...

  20. Industrial use of SPring-8 in fuel cell development

    International Nuclear Information System (INIS)

    Sugiura, Masahiro

    2007-01-01

    The study of fuel cells by using synchrotron radiation from SPring-8 was reviewed for polymer electrolyte fuel cells (PEFCs; also called proton exchange membrane fuel cells), solid oxide fuel cells (SOFCs), and fuel cell-related materials. PEFCs use a solid polymer as an electrolyte and porous carbon electrodes containing a platinum catalyst. Measurements of Pt particles in the cathode catalyst by x-ray absorption near-edge structure (XANES) showed that the decrease of the particle size of Pt particles caused an increased of the number of 5d orbital holes of Pt atoms. Oxidization processes of Pt particles were measured by time-resolved dispersive x-ray absorption fine structure (XAFS). Measurements by time-gating quick scan XAFS together with dispersive XAFS revealed the reduction-oxidation process of Pt nanoparticles under the operation condition of PEFCs. SOFCs use a hard, non-porous ceramic compound as the electrolyte. SOFCs are operated at very high temperatures - around 1,000degC. Oxides having perovskite and fluorite structures are one of the most promising materials for electrolyte of SOFCs operated at reduced temperatures. The local structures of doped ceria and lanthanum gallate compounds were studied by extended XAFS. It was indicated from the measurements of ionic conductivity of these compounds that the local structure seriously affected oxide ionic conduction. Residual thermal stresses in the electrolyte of the anode-supported planar SOFCs were measured by high-energy x-rays. The crystal structure and electron density distribution of hydrogen storage alloys were measured by x-ray diffraction. (Y.K.)

  1. The financial viability of an SOFC cogeneration system in single-family dwellings

    Science.gov (United States)

    Alanne, Kari; Saari, Arto; Ugursal, V. Ismet; Good, Joel

    In the near future, fuel cell-based residential micro-CHP systems will compete with traditional methods of energy supply. A micro-CHP system may be considered viable if its incremental capital cost compared to its competitors equals to cumulated savings during a given period of time. A simplified model is developed in this study to estimate the operation of a residential solid oxide fuel cell (SOFC) system. A comparative assessment of the SOFC system vis-à-vis heating systems based on gas, oil and electricity is conducted using the simplified model for a single-family house located in Ottawa and Vancouver. The energy consumption of the house is estimated using the HOT2000 building simulation program. A financial analysis is carried out to evaluate the sensitivity of the maximum allowable capital cost with respect to system sizing, acceptable payback period, energy price and the electricity buyback strategy of an energy utility. Based on the financial analysis, small (1-2 kW e) SOFC systems seem to be feasible in the considered case. The present study shows also that an SOFC system is especially an alternative to heating systems based on oil and electrical furnaces.

  2. Deposition and characterisation of epitaxial oxide thin films for SOFCs

    KAUST Repository

    Santiso, José

    2010-10-24

    This paper reviews the recent advances in the use of thin films, mostly epitaxial, for fundamental studies of materials for solid oxide fuel cell (SOFC) applications. These studies include the influence of film microstructure, crystal orientation and strain in oxide ionic conducting materials used as electrolytes, such as fluorites, and in mixed ionic and electronic conducting materials used as electrodes, typically oxides with perovskite or perovskite-related layered structures. The recent effort towards the enhancement of the electrochemical performance of SOFC materials through the deposition of artificial film heterostructures is also presented. These thin films have been engineered at a nanoscale level, such as the case of epitaxial multilayers or nanocomposite cermet materials. The recent progress in the implementation of thin films in SOFC devices is also reported. © 2010 Springer-Verlag.

  3. Electrode design for direct-methane micro-tubular solid oxide fuel cell (MT-SOFC)

    Science.gov (United States)

    Rabuni, Mohamad Fairus; Li, Tao; Punmeechao, Puvich; Li, Kang

    2018-04-01

    Herein, a micro-structured electrode design has been developed via a modified phase-inversion method. A thin electrolyte integrated with a highly porous anode scaffold has been fabricated in a single-step process and developed into a complete fuel cell for direct methane (CH4) utilisation. A continuous and well-dispersed layer of copper-ceria (Cu-CeO2) was incorporated inside the micro-channels of the anode scaffold. A complete cell was investigated for direct CH4 utilisation. The well-organised micro-channels and nano-structured Cu-CeO2 anode contributed to an increase in electrochemical reaction sites that promoted charge-transfer as well as facilitating gaseous fuel distribution, resulting in outstanding performances. Excellent electrochemical performances have been achieved in both hydrogen (H2) and CH4 operation. The power density of 0.16 Wcm-2 at 750 °C with dry CH4 as fuel is one of the highest ever reported values for similar anode materials.

  4. Study of synthesis routes and processing of NiO-YSZ ceramic composite for use as anode in solid oxide fuel cell (SOFC)

    International Nuclear Information System (INIS)

    Yoshito, Walter Kenji

    2011-01-01

    This study aim the definition of synthesis and ceramic processing conditions of the anodic component suitable for operation of SOFC, i.e, homogeneous distribution of NiO in YSZ matrix and porosity after reduction above 30%. The selected synthesis routes included the co-precipitation in ammonia media, mechanical mixing of powders and combustion reaction from nitrate salts. The characterization techniques of powders included the X-ray diffraction, scanning and transmission electron microscopy, laser diffraction, nitrogen gas adsorption technique (BET) and Helium pycnometry. The obtained results indicated that the loss of Ni 2+ in co-precipitation process, due to the formation of complex [Ni(NH 3 ) n ] 2+ , can be minimized by controlling the pH around 9.3, keeping the concentration of nickel cation in the solution to be precipitated around 0.1M. In the mechanical mixing method the best condition of powder dispersion, without differential sedimentation, was obtained for zeta potential values at pH around 8.0, fixing the dispersant concentration at 0.8%. For the combustion synthesis it was observed that when stoichiometric and twofold stoichiometric urea was used, amorphous phase was formed and a higher surface area was attained in the final products. Employing the fuel-rich solution condition, crystallization of the powder was observed and the relative intensity of reflections of XRD patterns increased with excess of fuel, due to increasing the reaction temperature. Sinterability studies of pellets prepared from powder synthesized by the three routes described above showed the temperature around 1300 deg C for maximum rate densification and porosity between 6.0 and 14%. Reduction results of the composites confirmed that the reduction kinetics occurs in two steps. The first one with a linear behavior and controlled by chemical reaction on the surface. The second reduction step is the reduction that is controlled by gas diffusion in micro pores, generated by reduction

  5. Liquid-fueled SOFC power sources for transportation

    Science.gov (United States)

    Myles, K. M.; Doshi, R.; Kumar, R.; Krumpelt, M.

    Traditionally, fuel cells have been developed for space or stationary terrestrial applications. As the first commercial 200-kW systems were being introduced by ONSI and Fuji Electric, the potentially much larger, but also more challenging, application in transportation was beginning to be addressed. As a result, fuel cell-powered buses have been designed and built, and R&D programs for fuel cell-powered passenger cars have been initiated. The engineering challenge of eventually replacing the internal combustion engine in buses, trucks, and passenger cars with fuel cell systems is to achieve much higher power densities and much lower costs than obtainable in systems designed for stationary applications. At present, the leading fuel cell candidate for transportation applications is, without question, the polymer electrolyte fuel cell (PEFC). Offering ambient temperature start-up and the potential for a relatively high power density, the polymer technology has attracted the interest of automotive manufacturers worldwide. But the difficulties of fuel handling for the PEFC have led to a growing interest in exploring the prospects for solid oxide fuel cells (SOFCs) operating on liquid fuels for transportation applications. Solid oxide fuel cells are much more compatible with liquid fuels (methanol or other hydrocarbons) and are potentially capable of power densities high enough for vehicular use. Two SOFC options for such use are discussed in this report.

  6. Origin of electrolyte-dopant dependent sulfur poisoning of SOFC anodes

    DEFF Research Database (Denmark)

    Zeng, Zhenhua; Björketun, Mårten E; Ebbesen, Sune

    2013-01-01

    The mechanisms governing the sulfur poisoning of the triple phase boundary (TPB) of Ni-XSZ (X2O3 stabilized zirconia) anodes have been investigated using density functional theory. The calculated sulfur adsorption energies reveal a clear correlation between the size of the cation dopant X3...

  7. Direct Simulation of Transport Properties from Three-Dimensional (3D) Reconstructed Solid-Oxide Fuel-Cell (SOFC) Electrode Microstructures

    International Nuclear Information System (INIS)

    Gunda, Naga Siva Kumar; Mitra, Sushanta K

    2012-01-01

    A well-known approach to develop a high efficiency solid-oxide fuel-cell (SOFC) consists of extracting the microstructure and transport properties such as volume fractions, internal surface area, geometric connectivity, effective gas diffusivity, effective electronic conductivity and geometric tortuosities from three-dimensional (3D) microstructure of the SOFC electrodes; thereafter, performing the SOFC efficiency calculations using previously mentioned quantities. In the present work, dual-beam focused ion beam - scanning electron microscopy (FIB-SEM) is applied on one of the SOFC cathodes, a lanthanum strontium manganite (LSM) electrode, to estimate the aforementioned properties. A framework for calculating transport properties is presented in this work. 3D microstructures of LSM electrode are reconstructed from a series of two-dimensional (2D) cross-sectional FIB-SEM images. Volume percentages of connected, isolated and dead-ends networks of pore and LSM phases are estimated. Different networks of pore and LSM phases are discretized with tetrahedral elements. Finally, the finite element method (FEM) is applied to calculate effective gas diffusivity and electronic conductivity of pore and LSM phases, respectively. Geometric tortuosities are estimated from the porosity and effective transport properties. The results obtained using FEM are compared with the finite volume method (FVM) results obtained by Gunda et al. [J. Power Sources, 196(7), 35929(2011)] and other numerical results obtained on randomly generated porous medium. Effect of consideration of dead-ends and isolated-ends networks on calculation of effective transport properties is studied.

  8. Effect of Lanthanum-Strontium Cathode Current-Collecting Layer on the Performance of Anode Supported Type Planar Solid Oxide Fuel Cells

    Science.gov (United States)

    Park, Sun-Young; Ji, Ho-Il; Kim, Hae-Ryoung; Yoon, Kyung Joong; Son, Ji-Won; Lee, Hae-Weon; Lee, Jong-Ho

    2013-07-01

    We applied screen-printed (La,Sr)CoO3 as a current-collecting layer of planar type unit-cell for lower temperature operation of SOFCs. In this study the effects of the cathode current-collecting layer on the performance of unit cell and symmetric half cell were investigated via AC and DC polarization experiments. According to our investigation, appropriately controlled current collecting layer was very effective to enhance the unit cell performance by reducing not only the ohmic resistance but also the polarization losses of SOFC cathode.

  9. Effect of stress on NiO reduction in solid oxide fuel cells: A new application of energy-resolved neutron imaging

    DEFF Research Database (Denmark)

    Makowska, Malgorzata; Strobl, Markus; Lauridsen, Erik Mejdal

    2015-01-01

    Recently, two new phenomena linking stress field and reduction rates in anode-supported solid oxide fuel cells (SOFCs) have been demonstrated, so-called accelerated creep during reduction and reduction rate enhancement and nucleation due to stress (Frandsen et al., 2014). These complex phenomena...

  10. Electroplating of Protective Coatings on Interconnects Used for Solid Oxide Fuel Cell Stacks

    DEFF Research Database (Denmark)

    Harthøj, Anders

    Solid oxide fuel Cell (SOFC) technology can with a high efficiency produce environmentally clean electricity by converting the chemical energy in a fuel to electrical energy. SOFC systems have a high operation temperature, approx. 600-850 °C. Advantages compared to other types of fuel cells......, are they can utilize a wide range of fuels, e.g. hydrogen, natural gas and methanol, do not contain noble metals and have a high efficiency. A major obstacle to the commercialization of SOFC technology is the high degradation rates and costs of the systems. A significant source of degradation is high...... on the side facing its anode. Two high temperature corrosion issues, which both affect the air side of the interconnect, are especially significant, both of: Formation of thick oxide scales on its surface and evaporation of chromium species from the oxide. The oxide scales increases the electrical resistance...

  11. Facts and figures, an International Energy Agency SOFC task report

    Energy Technology Data Exchange (ETDEWEB)

    Bossel, U G; Dubal, L [ed.

    1992-04-15

    The report covers the following themes: SOFC chemistry, properties of SOFC gases and materials, electrochemistry, electric current flow in SOFC elements, SOFC configurations, mass flow phenomena and linearized SOFC performance analysis. figs., tabs., 27 refs.

  12. Possible Future SOFC - ST Based Power Plants

    DEFF Research Database (Denmark)

    Rokni, Masoud; Scappin, Fabio

    2009-01-01

    Hybrid systems consisting Solid Oxide Fuel Cell (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas. A desulfurization reactor removes the sulfur content in the NG while a pre-reformer break down the heavier hydrocarbons. The pre-treated fuel enters...

  13. Effect of H{sub 2}S on the thermodynamic stability and electrochemical performance of Ni cermet-type of anodes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Venkateswara Rao, M.

    2006-11-15

    For SOFCs to be main means of power generation, they should be able to exploit wide variety of fuels. Among Ni-cermets, Ni-YSZ is the state-of-the-art materials for SOFC-anode which is the fuel electrode. But sulphur impurity present in different gaseous fuels (e.g Biogas), depending on its concentration, is highly poisonous to the stability and electrochemical performance of the Ni catalyst in the cermet anodes. Thus in this study the microstructural stability of Ni-YSZ, Ni-CGO and Ni-LSGM cermets in H{sub 2}S-containing hydrogen gas is studied in the intermediate temperature range of SOFC operation. Thermodynamic modelling of Ni-S-O-H quaternary system was performed for the calculation of thermodynamic stability and sulphur-tolerance limit of Ni in the gaseous atmosphere made up of H, O and S. The effect of presence H{sub 2}S in fuel gas, in the concentrations well below the thermodynamic tolerance limit, on the electrochemical performance of the anodes is studied by using model Ni-patterned electrodes on YSZ and LSGM. Thermodynamic modelling of the Ni-S-O-H quaternary was performed by employing CALPHAD methodology. The modelling of Ni-S binary phase diagram was performed by using sublattice models for the non-stoichiometric phases. The optimised binaries of Ni-O, and Ni-H were taken from the literature. The Ni-O-S and Ni-O-H ternaries were extrapolated from the lower order binaries. In Ni-O-S ternary, NiSO{sub 4} is the only ternary compound present. The ternary compounds, Ni(OH){sub 2} and NiOOH in the Ni-O-H ternary were considered as stoichiometric line compounds. The model parameters of the ternary compounds were optimised using the experimental data. The Ni-S-O-H quaternary was calculated by extrapolation method as employed in the CALPHAD methodology. Inorder to understand the H{sub 2}-oxidation mechanism and the role played by the electrolyte in the reaction mechanism, symmetrical cells of Ni-patterned YSZ single crystals with different crystallographic

  14. Stability, characterization and functionality of proton conducting NiO–BaCe0.85−xNbxY0.15O3−δ cermet anodes for IT-SOFC application

    International Nuclear Information System (INIS)

    Žunić, Milan; Branković, Goran; Basoli, Francesco; Cilense, Mario; Longo, Elson; Varela, José Arana

    2014-01-01

    Highlights: • The influence niobium concentration on properties of anode substrates was investigated. • The cermet anode powders were obtained without any undesirable phases. • Porous anode substrates showed chemical stability in the CO 2 atmosphere. • Conductivity values of reduced anode samples were σ * > 50 S cm −1 . • Fuel cell tests demonstrated functionality of anode substrates. - Abstract: There are many of properties of anodes based on proton conductors, like microstructure, conductivity and chemical stability, which should be optimized. In this work we were dealing with the influence of niobium on the chemical stability, microstructural and electrical characteristics of proton conducting NiO–BaCe 0.85−x Nb x Y 0.15 O 3−δ (NiO–BCNYx) anodes. Four anode substrates NiO–BCNYx of different Nb concentration were prepared using the method of evaporation and decomposition of solutions and suspensions (EDSS). Sintered anode substrates were reduced and their microstructural and electrical properties were examined before and after reduction as a function of the amount of niobium. Chemical stability tests showed strong influence of Nb amount on the chemical stability of anodes in the CO 2 . Microstructural properties of the anode pellets before and after testing in CO 2 were investigated using X-ray diffraction analysis. Electrical properties of anode samples were examined by impedance spectroscopy measurements and the conductivity values of reduced anodes were more than 50 S cm −1 at 600 °C confirming percolation through Ni particles. Fuel cells were fabricated with aim to examine the functionality of anodes. During the fuel cell test the cell with Ni–BCNY10 anode achieved the highest performance, demonstrating a peak power density of 164 mW cm −2 at 650 °C, which confirmed the functionality of Ni–BCNY anodes

  15. Montagem e caracterização elétrica de pilhas a combustível de óxido sólido (PaCOS Assembly and electrical characterization of solid oxide fuel cell stacks

    Directory of Open Access Journals (Sweden)

    Hosane Aparecida Tarôco

    2009-01-01

    Full Text Available This paper is focused on a review of the design features and the electrochemistry characterization of anode-supported planar SOFC. Studies and results of metallic alloy interconnectors and recovery for protection against corrosion and for contact layer are showed. Moreover a discussion of examples of measurements of impedance spectrometry, according to the literature and our experimental results are made. For the anode supported fuel cells the power density varies from 0.1 to 0.5 Wcm², according to results in the literature (showed in this paper. For electrolyte supported fuel cell the power density can be 10 Wcm-2 for high temperatures. An English-Portuguese glossary of most used terms in SOFC stack is given for greater clarity and to introduce new terms to the reader.

  16. Advanced gas-emission anode design for microfluidic fuel cell eliminating bubble accumulation

    International Nuclear Information System (INIS)

    Zhang, Hao; Xuan, Jin; Wang, Huizhi; Leung, Dennis Y C; Xu, Hong; Zhang, Li

    2017-01-01

    A microfluidic fuel cell is a low cost, easily fabricated energy device and is considered a promising energy supplier for portable electronics. However, the currently developed microfluidic fuel cells that are fed with hydrocarbon fuels are confronted with a bubble problem especially when operating at high current density conditions. In this work, a gas-emission anode is presented to eliminate the gas accumulation at the anode. This gas-emission anode is verified as a valid design for discharging gaseous products, which is especially beneficial for stable operation of microfluidic fuel cells. The electrochemical performance of a counter-flow microfluidic fuel cell equipped with a gas-emission anode was measured. The results indicate that the specific design of the gas-emission anode is essential for reducing the oxygen reduction reaction parasitic effect at the anode. Fuel utilization of 76.4% was achieved at a flow rate of 0.35 µ l min −1 . Current–voltage curves of single electrodes were measured and the parasitic effect at the anode was identified as the main performance limiting factor in the presented anode design. (paper)

  17. Improved Anode for a Direct Methanol Fuel Cell

    Science.gov (United States)

    Valdez, Thomas; Narayanan, Sekharipuram

    2005-01-01

    A modified chemical composition has been devised to improve the performance of the anode of a direct methanol fuel cell. The main feature of the modified composition is the incorporation of hydrous ruthenium oxide into the anode structure. This modification can reduce the internal electrical resistance of the cell and increase the degree of utilization of the anode catalyst. As a result, a higher anode current density can be sustained with a smaller amount of anode catalyst. These improvements can translate into a smaller fuel-cell system and higher efficiency of conversion. Some background information is helpful for understanding the benefit afforded by the addition of hydrous ruthenium oxide. The anode of a direct methanol fuel cell sustains the electro-oxidation of methanol to carbon dioxide in the reaction CH3OH + H2O--->CO2 + 6H(+) + 6e(-). An electrocatalyst is needed to enable this reaction to occur. The catalyst that offers the highest activity is an alloy of approximately equal numbers of atoms of the noble metals platinum and ruthenium. The anode is made of a composite material that includes high-surface-area Pt/Ru alloy particles and a proton-conducting ionomeric material. This composite is usually deposited onto a polymer-electrolyte (proton-conducting) membrane and onto an anode gas-diffusion/current-collector sheet that is subsequently bonded to the proton-conducting membrane by hot pressing. Heretofore, the areal density of noble-metal catalyst typically needed for high performance has been about 8 mg/cm2. However, not all of the catalyst has been utilized in the catalyzed electro-oxidation reaction. Increasing the degree of utilization of the catalyst would make it possible to improve the performance of the cell for a given catalyst loading and/or reduce the catalyst loading (thereby reducing the cost of the cell). The use of carbon and possibly other electronic conductors in the catalyst layer has been proposed for increasing the utilization of the

  18. Complete relaxation of residual stresses during reduction of solid oxide fuel cells

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

    2015-01-01

    reduce significantly over minutes. In this work the stresses are measured in-situ before and after the reduction by use of XRD. The phenomenon of accelerated creep has to be considered both in the production of stacks and in the analysis of the stress field in a stack based on anode supported SOFCs.......To asses the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. This work reports further details on a newly discovered creep phenomenon......, accelerated creep, taking place during the reduction of the anode. This relaxes stresses at a much higher rate (~×104) than creep during operation. The phenomenon has previously been studied by simultaneous loading and reduction. With the recorded high creep rates, the stresses at the time of reduction should...

  19. Trends for Methane Oxidation at Solid Oxide Fuel Cell Conditions

    DEFF Research Database (Denmark)

    Kleis, Jesper; Jones, Glenn; Abild-Pedersen, Frank

    2009-01-01

    First-principles calculations are used to predict a plausible reaction pathway for the methane oxidation reaction. In turn, this pathway is used to obtain trends in methane oxidation activity at solid oxide fuel cell (SOFC) anode materials. Reaction energetics and barriers for the elementary...... the Ni surfaces to other metals of interest. This allows the reactivity over the different metals to be understood in terms of two reactivity descriptors, namely, the carbon and oxygen adsorption energies. By combining a simple free-energy analysis with microkinetic modeling, activity landscapes of anode...

  20. Reversible operation of microtubular solid oxide cells using La0.6Sr0.4Co0.2Fe0.8O3-δ-Ce0.9Gd0.1O2-δ oxygen electrodes

    Science.gov (United States)

    López-Robledo, M. J.; Laguna-Bercero, M. A.; Larrea, A.; Orera, V. M.

    2018-02-01

    Yttria stabilized zirconia (YSZ) based microtubular solid oxide fuel cells (mT-SOFCs) using La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) and Ce0.9Gd0.1O2-δ (GDC) as the oxygen electrode, along with a porous GDC electrolyte-electrode barrier layer, were fabricated and characterized in both fuel cell (SOFC) and electrolysis (SOEC) operation modes. The cells were anode-supported, the NiO-YSZ microtubular supports being made by Powder Extrusion Moulding (PEM). The cells showed power densities of 695 mW cm-2 at 800 °C and 0.7 V in SOFC mode, and of 845 mA cm-2 at 800 °C and 1.3 V in SOEC mode. AC impedance experiments performed under different potential loads demonstrated the reversibility of the cells. These results showed that these cells, prepared with a method suitable for using on an industrial scale, are highly reproducible and reliable, as well as very competitive as reversible SOFC-SOEC devices operating at intermediate temperatures.

  1. Three-dimensional anode engineering for the direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, A.; Oloman, C.W.; Gyenge, E.L. [Department of Chemical and Biological Engineering, The University of British Columbia, 2360 East Mall, Vancouver, BC (Canada)

    2009-09-05

    Catalyzed graphite felt three-dimensional anodes were investigated in direct methanol fuel cells (DMFCs) operated with sulfuric acid supporting electrolyte. With a conventional serpentine channel flow field the preferred anode thickness was 100 {mu}m, while a novel flow-by anode showed the best performance with a thickness of 200-300 {mu}m. The effects of altering the methanol concentration, anolyte flow rate and operating temperature on the fuel cell superficial power density were studied by full (2{sup 3} + 1) factorial experiments on a cell with anode area of 5 cm{sup 2} and excess oxidant O{sub 2} at 200 kPa(abs). For operation in the flow-by mode with 2 M methanol at 2 cm{sup 3} min{sup -1} and 353 K the peak power density was 2380 W m{sup -2} with a PtRuMo anode catalyst, while a PtRu catalyst yielded 2240 W m{sup -2} under the same conditions. (author)

  2. Three-dimensional anode engineering for the direct methanol fuel cell

    Science.gov (United States)

    Bauer, A.; Oloman, C. W.; Gyenge, E. L.

    Catalyzed graphite felt three-dimensional anodes were investigated in direct methanol fuel cells (DMFCs) operated with sulfuric acid supporting electrolyte. With a conventional serpentine channel flow field the preferred anode thickness was 100 μm, while a novel flow-by anode showed the best performance with a thickness of 200-300 μm. The effects of altering the methanol concentration, anolyte flow rate and operating temperature on the fuel cell superficial power density were studied by full (2 3 + 1) factorial experiments on a cell with anode area of 5 cm 2 and excess oxidant O 2 at 200 kPa(abs). For operation in the flow-by mode with 2 M methanol at 2 cm 3 min -1 and 353 K the peak power density was 2380 W m -2 with a PtRuMo anode catalyst, while a PtRu catalyst yielded 2240 W m -2 under the same conditions.

  3. Degradation of some ceria electrolytes under hydrogen contact nearby anode in solid oxide fuel cells (SOFCs

    Directory of Open Access Journals (Sweden)

    Malta Luiz Fernando Brum

    2004-01-01

    Full Text Available This work is concerned with thermodynamic analysis of the stability of some ceria electrolytes under contact with hydrogen gas nearby anode in fuel cells. It was considered the following types of ceria-electrolytes: pure ceria, strontium-doped ceria, calcium-doped ceria and calcium-bismuth-doped ceria. The equilibrium Log (pH2O/pH2 vs. T diagrams were constructed for x = 0.1 and 0.01, where x is the fraction of initial ceria converted to Ce2O3 (proportional to the ratio between activities of Ce3+ and Ce4+ in the ceria electrolyte, which is proportional to the fraction of electronic conduction in the electrolyte at a given temperature. The predictions of the diagrams are as follows: (a Ce1.9Ca0.1Bi0.8O5.1 and Ce0.9Sr0.1O1.9 are less stable than pure ceria for the whole temperature range (from 0 to 1000 °C; (b Ce0.9Ca0.1O1.9 is more stable than pure ceria below about 650 °C for x = 0.1 and below about 400 °C for x = 0.01; (c at each temperature in the considered range the pressure ratio pH2O(g/pH2(g has to be higher than thermodynamically predicted in order to keep CeO2 stable in the electrolyte contacting hydrogen gas. Thermodynamic predictions are entirely capable of explaining experimental data published on the subject (irreversible cell degradation in the case of SrO-doped ceria; weight loss from doped-ceria electrolyte above 700 °C; oxygen gas release during sintering of ceria.

  4. Study on durability for thermal cycle of planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Motoo; Nakata, Kei-ichi; Wakayama, Sin-ichi [Tonen Corp., Saitama (Japan)] [and others

    1996-12-31

    TONEN CORPORATION has developed planar type SOFC since 1986. We demonstrated the output of 1.3 kW in 1991 and 5.1 kW in 1995. Simultaneously we have studied how to raise electric efficiency and reliability utilizing hydrogen and propane as fuel. Durability for thermal cycle is one of the most important problems of planar SOFC to make it more practical. The planar type SOFC is made up of separator, zirconia electrolyte and glass sealant. The thermal expansion of these components are expected to be the same value, however, they still possess small differences. In this situation, a thermal cycle causes a thermal stress due to the difference of the cell components and is often followed by a rupture in cell components, therefore, the analysis of the thermal stress should give us much useful information. The thermal cycle process consists of a heating up and cooling down procedure. Zirconia electrolyte is not bonded to the separator under the condition of the initial heating up procedure, and glass sealant becomes soft or melts and glass seals spaces between the zirconia and separator. The glass sealant becomes harder with the cooling down procedure. Moreover, zirconia is tightly bonded with separator below a temperature which is defined as a constraint temperature and thermal stress also occurs. This indicates that the heating up process relaxes the thermal stress and the cooling down increases it. In this paper, we simulated dependence of the stress on the sealing configuration, thermal expansion of sealant and constraint temperature of sealant glass. Furthermore, we presented SOFC electrical properties after a thermal cycle.

  5. Cell and method for electrolysis of water and anode

    Science.gov (United States)

    Aylward, J. R. (Inventor)

    1981-01-01

    An electrolytic cell for converting water vapor to oxygen and hydrogen include an anode comprising a foraminous conductive metal substrate with a 65-85 weight percent iridium oxide coating and 15-35 weight percent of a high temperature resin binder. A matrix member contains an electrolyte to which a cathode substantially inert. The foraminous metal member is most desirably expanded tantalum mesh, and the cell desirably includes reservoir elements of porous sintered metal in contact with the anode to receive and discharge electrolyte to the matrix member as required. Upon entry of a water vapor containing airstream into contact with the outer surface of the anode and thence into contact with iridium oxide coating, the water vapor is electrolytically converted to hydrogen ions and oxygen with the hydrogen ions migrating through the matrix to the cathode and the oxygen gas produced at the anode to enrich the air stream passing by the anode.

  6. Solid Oxide Fuel Cells coupled with a biomass gasification unit

    Directory of Open Access Journals (Sweden)

    Skrzypkiewicz Marek

    2016-01-01

    Full Text Available A possibility of fuelling a solid oxide fuel cell stack (SOFC with biomass fuels can be realized by coupling a SOFC system with a self-standing gasification unit. Such a solution enables multi-fuel operation, elasticity of the system as well as the increase of the efficiency of small-scale biomass-to-electricity conversion units. A system of this type, consisting of biomass gasification unit, gas purification unit, SOFC stack, anode off-gas afterburner and peripherals was constructed and operated successfully. During the process, biomass fuel (wood chips was gasified with air as gasification agent. The gasifier was capable of converting up to 30 kW of fuel to syngas with efficiencies up to 75%. Syngas leaving the gasification unit is delivered to a medium temperature adsorber for sulphur compounds removal. Steam is added to the purified fuel to maintain steam to carbon ratio higher than 2. The syngas then is passed to a SOFC stack through a fuel preheater. In such a configuration it was possible to operate a commercial 1.3 kW stack within its working regime. Conducted tests confirmed successful operation of a SOFC stack fuelled by biomass-sourced syngas.

  7. Novel Fuel Cells for Coal Based Systems

    Energy Technology Data Exchange (ETDEWEB)

    Thomas Tao

    2011-12-31

    The goal of this project was to acquire experimental data required to assess the feasibility of a Direct Coal power plant based upon an Electrochemical Looping (ECL) of Liquid Tin Anode Solid Oxide Fuel Cell (LTA-SOFC). The objective of Phase 1 was to experimentally characterize the interaction between the tin anode, coal fuel and cell component electrolyte, the fate of coal contaminants in a molten tin reactor (via chemistry) and their impact upon the YSZ electrolyte (via electrochemistry). The results of this work will provided the basis for further study in Phase 2. The objective of Phase 2 was to extend the study of coal impurities impact on fuel cell components other than electrolyte, more specifically to the anode current collector which is made of an electrically conducting ceramic jacket and broad based coal tin reduction. This work provided a basic proof-of-concept feasibility demonstration of the direct coal concept.

  8. Simultaneous NOx and hydrocarbon emissions control for lean-burn engines using low-temperature solid oxide fuel cell at open circuit.

    Science.gov (United States)

    Huang, Ta-Jen; Hsu, Sheng-Hsiang; Wu, Chung-Ying

    2012-02-21

    The high fuel efficiency of lean-burn engines is associated with high temperature and excess oxygen during combustion and thus is associated with high-concentration NO(x) emission. This work reveals that very high concentration of NO(x) in the exhaust can be reduced and hydrocarbons (HCs) can be simultaneously oxidized using a low-temperature solid oxide fuel cell (SOFC). An SOFC unit is constructed with Ni-YSZ as the anode, YSZ as the electrolyte, and La(0.6)Sr(0.4)CoO(3) (LSC)-Ce(0.9)Gd(0.1)O(1.95) as the cathode, with or without adding vanadium to LSC. SOFC operation at 450 °C and open circuit can effectively treat NO(x) over the cathode at a very high concentration in the simulated exhaust. Higher NO(x) concentration up to 5000 ppm can result in a larger NO(x) to N(2) rate. Moreover, a higher oxygen concentration promotes NO conversion. Complete oxidation of HCs can be achieved by adding silver to the LSC current collecting layer. The SOFC-based emissions control system can treat NO(x) and HCs simultaneously, and can be operated without consuming the anode fuel (a reductant) at near the engine exhaust temperature to eliminate the need for reductant refilling and extra heating.

  9. Preparation of Ni-Fe bimetallic porous anode support for solid oxide fuel cells using LaGaO{sub 3} based electrolyte film with high power density

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Young-Wan; Ida, Shintaro; Ishihara, Tatsumi [Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Motooka 744, Nishi-Ku, Fukuoka 819-0395 (Japan); Eto, Hiroyuki [Mitsubishi Materials Corporation, Central Research Institute, 1002-14 Mukohyama, Naka-Shi, Ibaraki 311-0102 (Japan); Inagaki, Toru [The Kansai Electric Power Co., Inc., 11-20 Nakoji 3-Chome, Amagasaki, Hyogo 661-0974 (Japan)

    2010-10-01

    Optimization of sintering temperature for NiO-Fe{sub 2}O{sub 3} composite oxide substrate was studied in order to obtain a dense substrate with smooth surface. By in situ reduction, the substrate was changed to a porous Ni-Fe alloy metal. The volumetric shrinkage and porosity of the substrate were also studied systematically with the Ni-Fe substrate reduced at different temperatures. A Sr and Mg-doped LaGaO{sub 3} (LSGM) thin film was prepared on dense substrate by the pulsed laser deposition (PLD) method. The LSGM film with stoichiometric composition was successfully prepared under optimal deposition parameters and a target composition. Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3} (SSC55) cathode was prepared by the slurry coating method on the deposited film. Prepared SOFC single cell shows high power density and the maximum power density (MPD) achieved was 1.79, 0.82 and 0.29 W cm{sup -2} at 973, 873 and 773 K, respectively. After thermal cycle from 973 to 298 K, the cell shows almost theoretical open circuit potential (1.1 V) and the power density of 1.62 W cm{sup -2}, which is almost the same as that at first cycles. Therefore, the Ni-Fe porous metal support made by the selective reduction is highly promising as a metal anode substrate for SOFC using LaGaO{sub 3} thin film. (author)

  10. Mosaic-shaped cathode for highly durable solid oxide fuel cell under thermal stress

    Science.gov (United States)

    Joo, Jong Hoon; Jeong, Jaewon; Kim, Se Young; Yoo, Chung-Yul; Jung, Doh Won; Park, Hee Jung; Kwak, Chan; Yu, Ji Haeng

    2014-02-01

    In this study, we propose a novel "mosaic structure" for a SOFC (solid oxide fuel cell) cathode with high thermal expansion to improve the stability against thermal stress. Self-organizing mosaic-shaped cathode has been successfully achieved by controlling the amount of binder in the dip-coating solution. The anode-supported cell with mosaic-shaped cathode shows itself to be highly durable performance for rapid thermal cycles, however, the performance of the cell with a non-mosaic cathode exhibits severe deterioration originated from the delamination at the cathode/electrolyte interface after 7 thermal cycles. The thermal stability of an SOFC cathode can be evidently improved by controlling the surface morphology. In view of the importance of the thermal expansion properties of the cathode, the effects of cathode morphology on the thermal stress stability are discussed.

  11. Thermodynamic analysis of an integrated solid oxide fuel cell cycle with a rankine cycle

    International Nuclear Information System (INIS)

    Rokni, Masoud

    2010-01-01

    Hybrid systems consisting of solid oxide fuel cells (SOFC) on the top of a steam turbine (ST) are investigated. The plants are fired by natural gas (NG). A desulfurization reactor removes the sulfur content in the fuel while a pre-reformer breaks down the heavier hydro-carbons. The pre-treated fuel enters then into the anode side of the SOFC. The remaining fuels after the SOFC stacks enter a burner for further burning. The off-gases are then used to produce steam for a Rankine cycle in a heat recovery steam generator (HRSG). Different system setups are suggested. Cyclic efficiencies up to 67% are achieved which is considerably higher than the conventional combined cycles (CC). Both adiabatic steam reformer (ASR) and catalytic partial oxidation (CPO) fuel pre-reformer reactors are considered in this investigation.

  12. Simulation and Parametric Analysis of a Hybrid SOFC-Gas Turbine Power Generation System

    International Nuclear Information System (INIS)

    Hassan, A.M.; Fahmy

    2004-01-01

    Combined SOFC-Gas Turbine Power Generation Systems are aimed to increase the power and efficiency obtained from the technology of using high temperature fuel cells by integrating them with gas turbines. Hybrid systems are considered in the last few years as one of the most promising technologies to obtain electric energy from the natural gas at very high efficiency with a serious potential for commercial use. The use of high temperature allows internal reforming for natural gas and thus disparity of fuel composition is allowed. Also air preheating is performed thanks to the high operating cell temperature as a task of energy integration. In this paper a modeling approach is presented for the fuel cell-gas turbine hybrid power generation systems, to obtain the sofc output voltage, power, and the overall hybrid system efficiency. The system has been simulated using HYSYS, the process simulation software to help improving the process understanding and provide a quick system solution. Parametric analysis is also presented in this paper to discuss the effect of some important SOFC operating parameters on the system performance and efficiency

  13. Nanoporous anodic aluminum oxide with a long-range order and tunable cell sizes by phosphoric acid anodization on pre-patterned substrates

    Science.gov (United States)

    Surawathanawises, Krissada; Cheng, Xuanhong

    2014-01-01

    Nanoporous anodic aluminum oxide (AAO) has been explored for various applications due to its regular cell arrangement and relatively easy fabrication processes. However, conventional two-step anodization based on self-organization only allows the fabrication of a few discrete cell sizes and formation of small domains of hexagonally packed pores. Recent efforts to pre-pattern aluminum followed with anodization significantly improve the regularity and available pore geometries in AAO, while systematic study of the anodization condition, especially the impact of acid composition on pore formation guided by nanoindentation is still lacking. In this work, we pre-patterned aluminium thin films using ordered monolayers of silica beads and formed porous AAO in a single-step anodization in phosphoric acid. Controllable cell sizes ranging from 280 nm to 760 nm were obtained, matching the diameters of the silica nanobead molds used. This range of cell size is significantly greater than what has been reported for AAO formed in phosphoric acid in the literature. In addition, the relationships between the acid concentration, cell size, pore size, anodization voltage and film growth rate were studied quantitatively. The results are consistent with the theory of oxide formation through an electrochemical reaction. Not only does this study provide useful operational conditions of nanoindentation induced anodization in phosphoric acid, it also generates significant information for fundamental understanding of AAO formation. PMID:24535886

  14. Fabrication of 10%Gd-doped ceria (GDC)/NiO-GDC half cell for low or intermediate temperature solid oxide fuel cells using spray pyrolysis

    DEFF Research Database (Denmark)

    Chourashiya, M. G.; Bhardwaj, S. R.; Jadhav, L. D.

    2010-01-01

    temperature SOFCs. Additionally, if GDC is employed in thin film form, rather higher ionic conductivity at further lower temperatures can be obtained and thereby allowing its use in low temperature SOFC. In the present investigation, the preparative parameters of spray pyrolysis technique (SPT) were optimized...... SEM observations of post heat-treated (at 1,000 °C) GDC/NiO-GDC structure revealed that GDC films were uniform in thickness with improved adherence to substrate. The relative density of post heat-treated films was of the order of 96%, which was attributed to the presence of nano-granules in the thin...... to deposit dense and adherent films of GDC on ceramic substrate. NiO-GDC was used as ceramic substrate, which also acts as a precursor composite anode for GDC-based SOFCs. Prepared half cells (GDC/NiO-GDC) were characterized using XRD, SEM, and electrochemical impedance spectroscopy. The surface and fractal...

  15. Dynamic Analysis of Load Operations of Two-Stage SOFC Stacks Power Generation System

    Directory of Open Access Journals (Sweden)

    Paulina Pianko-Oprych

    2017-12-01

    Full Text Available The main purpose of this paper was to develop a complete dynamic model of a power generation system based on two serially connected solid oxide fuel cell stacks. The uniqueness of this study lies in a different number of fuel cells in the stacks. The model consists of the electrochemical model, mass and energy balance equations implemented in MATLAB Simulink environment. Particular attention has been paid to the analysis of the transient response of the reformers, fuel cells and the burner. The dynamic behavior of the system during transient conditions was investigated by load step changing. The model evaluates electrical and thermal responses of the system at variable drawn current. It was found that a decrease of 40% in the 1st stage and 2nd solid oxide fuel cell (SOFC stacks drawn current caused both stacks temperature to drop by 2%. An increase of the cell voltage for the 1st and 2nd SOFC stacks led to very fast steam reformer response combined with a slight decrease in reformer temperature, while a considerable burner temperature increase of 70 K can be observed. Predictions of the model provide the basic insight into the operation of the power generation-based SOFC system during various transients and support its further design modifications.

  16. Evolution of thermal stress and failure probability during reduction and re-oxidation of solid oxide fuel cell

    Science.gov (United States)

    Wang, Yu; Jiang, Wenchun; Luo, Yun; Zhang, Yucai; Tu, Shan-Tung

    2017-12-01

    The reduction and re-oxidation of anode have significant effects on the integrity of the solid oxide fuel cell (SOFC) sealed by the glass-ceramic (GC). The mechanical failure is mainly controlled by the stress distribution. Therefore, a three dimensional model of SOFC is established to investigate the stress evolution during the reduction and re-oxidation by finite element method (FEM) in this paper, and the failure probability is calculated using the Weibull method. The results demonstrate that the reduction of anode can decrease the thermal stresses and reduce the failure probability due to the volumetric contraction and porosity increasing. The re-oxidation can result in a remarkable increase of the thermal stresses, and the failure probabilities of anode, cathode, electrolyte and GC all increase to 1, which is mainly due to the large linear strain rather than the porosity decreasing. The cathode and electrolyte fail as soon as the linear strains are about 0.03% and 0.07%. Therefore, the re-oxidation should be controlled to ensure the integrity, and a lower re-oxidation temperature can decrease the stress and failure probability.

  17. Comparison of the multicomponent mass transfer models for the prediction of the concentration overpotential for solid oxide fuel cell anodes

    Energy Technology Data Exchange (ETDEWEB)

    Vural, Yasemin; Ma, Lin; Ingham, Derek B.; Pourkashanian, Mohamed [Centre for Computational Fluid Dynamics, University of Leeds, Leeds (United Kingdom)

    2010-08-01

    In this study, multicomponent mass diffusion models, namely the Stefan-Maxwell model (SMM), the Dusty Gas model (DGM) and the Binary Friction model (BFM) have been compared in terms of their predictive capabilities of the concentration polarization of an anode supported solid oxide fuel cell (SOFC) anode. The results show that other than the pore diameter, current density and concentration of reactants, which have a high importance in concentration polarization predictions, the tortuosity (or porosity/tortuosity) term, has a substantial effect on the model predictions. Contrary to the previous discussions in the literature, for the fitted value of tortuosities, SMM and DGM predictions are similar, even for an average pore radius as small as 2.6e-07 and current density as high as 1.5 A cm{sup -2}. Also it is shown that the BFM predictions are similar to DGM for the case investigated in this study. Moreover, in this study, the effect of the pressure gradient term in the DGM and the BFM has been investigated by including and excluding this term from the model equations. It is shown that for the case investigated and model assumptions used in this study, the terms including the pressure coefficient have an insignificant effect on the predictions of both DGM and BFM and therefore they can be neglected. (author)

  18. Impedance of SOFC electrodes: A review and a comprehensive case study on the impedance of LSM:YSZ cathodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Hjelm, Johan

    2014-01-01

    It was shown through a comprehensive impedance spectroscopy study that the impedance of the classic composite LSM:YSZ (lanthanum strontium manganite and yttria stabilized zirconia) solid oxide fuel cell (SOFC) cathode can be described well with porous electrode theory. Furthermore, it was illustr......It was shown through a comprehensive impedance spectroscopy study that the impedance of the classic composite LSM:YSZ (lanthanum strontium manganite and yttria stabilized zirconia) solid oxide fuel cell (SOFC) cathode can be described well with porous electrode theory. Furthermore......, it was illustrated through a literature review on SOFC electrodes that porous electrode theory not only describes the classic LSM:YSZ SOFC cathode well, but SOFC electrodes in general. The extensive impedance spectroscopy study of LSM:YSZ cathodes consisted of measurements on cathodes with three different sintering...... temperatures and hence different microstructures and varying degrees of LSM/YSZ solid state interactions. LSM based composite cathodes, where YSZ was replaced with CGO was also studied in order to acquire further knowledge on the chemical compatibility between LSM and YSZ. All impedance measurements were...

  19. Combining science and practice in the Danish DK-SOFC program

    DEFF Research Database (Denmark)

    Knudsen, P.; Bagger, C.; Mogensen, Mogens Bjerg

    1994-01-01

    A three-year solid oxide fuel cells (SOFC) development program completed in 1992 has produced 10 cm2 cells with area-specific resistances in the range 0.25 to 0.40 OMEGA cm2 at 1000-degrees-C. Cathode and interconnect materials were produced in the program. Sintering of electrodes, electrolyte...

  20. Status of Development and Manufacture of Solid Oxide Fuel Cell at Topsoe Fuel Cell A/S and Risø/DTU

    DEFF Research Database (Denmark)

    Christiansen, Niels; Holm-Larsen, Helge; Jørgensen, Mette Juel

    2009-01-01

    Laboratory (Risø/DTU) which includes material synthesis and cost effective ceramic manufacturing methods for anode and metal supported flat planar cells in addition to multilayer assembling for compact stacks with metallic interconnects. The development is focussing on high electrochemical performance...... in SOFC technology includes system development in collaboration with system partners and development and manufacturing of integrated stack assemblies called PowerCore. ©2009 COPYRIGHT ECS - The Electrochemical Society...

  1. Demonstration of high efficiency intermediate-temperature solid oxide fuel cell based on lanthanum gallate electrolyte

    International Nuclear Information System (INIS)

    Inagaki, Toru; Nishiwaki, Futoshi; Kanou, Jirou; Yamasaki, Satoru; Hosoi, Kei; Miyazawa, Takashi; Yamada, Masaharu; Komada, Norikazu

    2006-01-01

    The Kansai Electric Power Co., Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been jointly developing intermediate-temperature solid oxide fuel cells (SOFCs). The operation temperatures between 600 and 800 o C were set as the target, which enable SOFC to use less expensive metallic separators for cell-stacking and to carry out internal reforming of hydrocarbon fuels. The electrolyte-supported planar-type cells were fabricated using highly conductive lanthanum gallate-based electrolyte, La(Sr)Ga(Mg,Co)O 3-δ , Ni-(CeO 2 ) 1-x (SmO 1.5 ) x cermet anode, and Sm(Sr)CoO 3-δ cathode. The 1 kW-class power generation modules were fabricated using a seal-less stack of the cells and metallic separators. The 1 kW-class prototype power generation system with the module was developed with the high performance cell, which showed the thermally self-sustainability. The system included an SOFC module, a dc-ac inverter, a desulfurizer, and a heat recovery unit. It provided stable ac power output of 1 kW with the electrical efficiency of 45% LHV based on ac output by using city gas as a fuel, which was considered to be excellent for such a small power generation system. And the hot water of 90 o C was obtained using high temperature off-gas from SOFC

  2. Demonstration of high efficiency intermediate-temperature solid oxide fuel cell based on lanthanum gallate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Inagaki, Toru [Kansai Electric Power Co. Inc., Energy Use R and D Center, 11-20 Nakoji 3-chome, Amagasaki, Hyogo 661-0974 (Japan)]. E-mail: inagaki@rdd.kepco.co.jp; Nishiwaki, Futoshi [Kansai Electric Power Co. Inc., Energy Use R and D Center, 11-20 Nakoji 3-chome, Amagasaki, Hyogo 661-0974 (Japan); Kanou, Jirou [Kansai Electric Power Co. Inc., Energy Use R and D Center, 11-20 Nakoji 3-chome, Amagasaki, Hyogo 661-0974 (Japan); Yamasaki, Satoru [Kansai Electric Power Co. Inc., Energy Use R and D Center, 11-20 Nakoji 3-chome, Amagasaki, Hyogo 661-0974 (Japan); Hosoi, Kei [Mitsubishi Materials Corporation, Central Research Institute, 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan); Miyazawa, Takashi [Mitsubishi Materials Corporation, Central Research Institute, 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan); Yamada, Masaharu [Mitsubishi Materials Corporation, Central Research Institute, 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan); Komada, Norikazu [Mitsubishi Materials Corporation, Central Research Institute, 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan)

    2006-02-09

    The Kansai Electric Power Co., Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been jointly developing intermediate-temperature solid oxide fuel cells (SOFCs). The operation temperatures between 600 and 800 {sup o}C were set as the target, which enable SOFC to use less expensive metallic separators for cell-stacking and to carry out internal reforming of hydrocarbon fuels. The electrolyte-supported planar-type cells were fabricated using highly conductive lanthanum gallate-based electrolyte, La(Sr)Ga(Mg,Co)O{sub 3-{delta}}, Ni-(CeO{sub 2}){sub 1-x}(SmO{sub 1.5}) {sub x} cermet anode, and Sm(Sr)CoO{sub 3-{delta}} cathode. The 1 kW-class power generation modules were fabricated using a seal-less stack of the cells and metallic separators. The 1 kW-class prototype power generation system with the module was developed with the high performance cell, which showed the thermally self-sustainability. The system included an SOFC module, a dc-ac inverter, a desulfurizer, and a heat recovery unit. It provided stable ac power output of 1 kW with the electrical efficiency of 45% LHV based on ac output by using city gas as a fuel, which was considered to be excellent for such a small power generation system. And the hot water of 90 {sup o}C was obtained using high temperature off-gas from SOFC.

  3. Structural comparison of anodic nanoporous-titania fabricated from single-step and three-step of anodization using two paralleled-electrodes anodizing cell

    Directory of Open Access Journals (Sweden)

    Mallika Thabuot

    2016-02-01

    Full Text Available Anodization of Ti sheet in the ethylene glycol electrolyte containing 0.38wt% NH4F with the addition of 1.79wt% H2O at room temperature was studied. Applied potential of 10-60 V and anodizing time of 1-3 h were conducted by single-step and three-step of anodization within the two paralleled-electrodes anodizing cell. Their structural and textural properties were investigated by X-ray diffraction (XRD and scanning electron microscopy (SEM. After annealing at 600°C in the air furnace for 3 h, TiO2-nanotubes was transformed to the higher proportion of anatase crystal phase. Also crystallization of anatase phase was enhanced as the duration of anodization as the final step increased. By using single-step of anodization, pore texture of oxide film was started to reveal at the applied potential of 30 V. Better orderly arrangement of the TiO2-nanotubes array with larger pore size was obtained with the increase of applied potential. The applied potential of 60 V was selected for the three-step of anodization with anodizing time of 1-3 h. Results showed that the well-smooth surface coverage with higher density of porous-TiO2 was achieved using prolonging time at the first and second step, however, discontinuity tube in length was produced instead of the long-vertical tube. Layer thickness of anodic oxide film depended on the anodizing time at the last step of anodization. More well arrangement of nanostructured-TiO2 was produced using three-step of anodization under 60 V with 3 h for each step.

  4. Towards anode with low indium content as effective anode in organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Touihri, S. [Unite de Physique des Dispositifs a Semi-conducteurs, Universite El Manar Faculte des Sciences de Tunis, Campus Universitaire 2092 (Tunisia); Cattin, L.; Nguyen, D-T. [LUNAM, Universite de Nantes, Institut Jean Rouxel (IMN), UMR 6502, 2 rue de la Houssiniere, BP 92208, Nantes F-44322 (France); Morsli, M. [LUNAM, Universite de Nantes, Faculte des Sciences et des Techniques, 2 rue de la Houssiniere, BP 92208, Nantes F-44322 (France); Louarn, G. [LUNAM, Universite de Nantes, Institut Jean Rouxel (IMN), UMR 6502, 2 rue de la Houssiniere, BP 92208, Nantes F-44322 (France); Bouteville, A.; Froger, V. [Arts et Metiers Paris Tech Angers, Laboratoire Procedes-Materiaux-Instrumentation, 2, bd du Ronceray, BP 3525, 49035 Angers Cedex (France); Bernede, J.C., E-mail: jean-christian.bernede@univ-nantes.fr [LUNAM, Universite de Nantes, Moltech Anjou, CNRS, UMR 6200, FSTN, 2 Rue de la Houssiniere, BP 92208, Nantes F-44322 (France)

    2012-01-15

    In{sub 2}O{sub 3} thin films (100 nm thick) have been deposited by reactive evaporation of indium, in an oxygen partial atmosphere. Conductive ({sigma} = 3.5 Multiplication-Sign 10{sup 3} S/cm) and transparent films are obtained using the following experimental conditions: oxygen partial pressure = 1 Multiplication-Sign 10{sup -1} Pa, substrate temperature = 300 Degree-Sign C and deposition rate = 0.02 nm/s. Layers of this In{sub 2}O{sub 3} thick of 5 nm have been introduced in AZO/In{sub 2}O{sub 3} and FTO/In{sub 2}O{sub 3} multilayer anode structures. The performances of organic photovoltaic cells, based on the couple CuPc/C{sub 60}, are studied using the anode as parameter. In addition to these bilayers, other structures have been used as anode: AZO, FTO, AZO/In{sub 2}O{sub 3}/MoO{sub 3}, FTO/In{sub 2}O{sub 3}/MoO{sub 3} and FTO/MoO{sub 3}. It is shown that the use of the In{sub 2}O{sub 3} film in the bilayer structures improves significantly the cell performances. However the open circuit voltage is quite small while better efficiencies are achieved when MoO{sub 3} is present. These results are discussed in the light of surface roughness and surface work function of the different anodes.

  5. Deposition and characterisation of epitaxial oxide thin films for SOFCs

    KAUST Repository

    Santiso, José ; Burriel, Mó nica

    2010-01-01

    This paper reviews the recent advances in the use of thin films, mostly epitaxial, for fundamental studies of materials for solid oxide fuel cell (SOFC) applications. These studies include the influence of film microstructure, crystal orientation

  6. Polarization properties of La0.6Sr0.4Co0.2Fe0.8O3-based double layer-type oxygen electrodes for reversible SOFCs

    International Nuclear Information System (INIS)

    Tao, Y.; Nishino, H.; Ashidate, S.; Kokubo, H.; Watanabe, M.; Uchida, H.

    2009-01-01

    We have developed double layer-type (catalyst layer/current collecting layer) oxygen electrodes (DLE) for reversible SOFCs. As the catalyst layer (cathode for SOFC and anode for steam electrolysis) interfaced with a samaria-doped ceria [(CeO 2 ) 0.8 (SmO 1.5 ) 0.2 , SDC] interlayer/YSZ solid electrolyte, mixed conducting La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) and SDC particles were employed. The current collecting porous LSCF layer was formed on the catalyst layer. By controlling the SDC content, as well as the thickness and porosity of the catalyst layer, the gas diffusion rate and the conduction networks for electrons and oxide ions were optimized, resulting in a marked reduction of the overpotential. The LSCF + SDC/LSCF DLE exhibited higher performance than single-layer electrodes of LSCF + SDC or LSCF; the IR-free anode potential vs. an air reference electrode was 0.12 V (corresponding to an overpotential of 0.08 V) at 0.5 A cm -2 and 900 deg. C under an atmosphere of O 2 (1 atm)

  7. Surface nanotopography of an anodized Ti–6Al–7Nb alloy enhances cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Her-Hsiung [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung 404, Taiwan (China); Department of Biomedical Informatics, Asia University, Taichung 413, Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei 112, Taiwan (China); Wu, Chia-Ping [Institute of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Sun, Ying-Sui [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Yang, Wei-En [Institute of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Lee, Tzu-Hsin, E-mail: biomaterials@hotmail.com [School of Dentistry, Chung Shan Medical University, Taichung 402, Taiwan (China); Oral Medicine Center, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China)

    2014-12-05

    Highlights: • An electrochemical anodization was applied to α/β-type Ti–6Al–7Nb alloy surface. • Anodized surface had a nontoxic nanoporous topography. • Anodized surface increased proteins adsorption due to nanotopography. • Anodized surface enhanced cell growth due to nanotopography. • Electrochemical anodization has potential as implant surface treatment. - Abstract: The α/β-type Ti–6Al–7Nb alloy is a potential replacement for α/β-type Ti–6Al–4V alloy, which is widely used in biomedical implant applications. The biological response to implant material is dependent on the surface characteristics of the material. In the present study, a simple and fast process was developed to perform an electrochemical anodization treatment on Ti–6Al–7Nb alloy. The proposed process yielded a thin surface nanotopography, which enhanced cell growth on the Ti–6Al–7Nb alloy. The surface characteristics, including the morphology, wettability, and protein adsorption, were investigated, and the cytotoxicity was evaluated according to International Organization for Standardization 10993-5 specifications. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed via fluorescence microscopy and scanning electron microscopy. The anodization process produced a surface nanotopography (pore size <100 nm) on anodized Ti–6Al–7Nb alloy, which enhanced the wettability, protein adsorption, cell adhesion, cell migration, and cell mineralization. The results showed that the surface nanotopography produced using the proposed electrochemical anodization process enhanced cell growth on anodized Ti–6Al–7Nb alloy for implant applications.

  8. Surface nanotopography of an anodized Ti–6Al–7Nb alloy enhances cell growth

    International Nuclear Information System (INIS)

    Huang, Her-Hsiung; Wu, Chia-Ping; Sun, Ying-Sui; Yang, Wei-En; Lee, Tzu-Hsin

    2014-01-01

    Highlights: • An electrochemical anodization was applied to α/β-type Ti–6Al–7Nb alloy surface. • Anodized surface had a nontoxic nanoporous topography. • Anodized surface increased proteins adsorption due to nanotopography. • Anodized surface enhanced cell growth due to nanotopography. • Electrochemical anodization has potential as implant surface treatment. - Abstract: The α/β-type Ti–6Al–7Nb alloy is a potential replacement for α/β-type Ti–6Al–4V alloy, which is widely used in biomedical implant applications. The biological response to implant material is dependent on the surface characteristics of the material. In the present study, a simple and fast process was developed to perform an electrochemical anodization treatment on Ti–6Al–7Nb alloy. The proposed process yielded a thin surface nanotopography, which enhanced cell growth on the Ti–6Al–7Nb alloy. The surface characteristics, including the morphology, wettability, and protein adsorption, were investigated, and the cytotoxicity was evaluated according to International Organization for Standardization 10993-5 specifications. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed via fluorescence microscopy and scanning electron microscopy. The anodization process produced a surface nanotopography (pore size <100 nm) on anodized Ti–6Al–7Nb alloy, which enhanced the wettability, protein adsorption, cell adhesion, cell migration, and cell mineralization. The results showed that the surface nanotopography produced using the proposed electrochemical anodization process enhanced cell growth on anodized Ti–6Al–7Nb alloy for implant applications

  9. Synthesis and characterization of nanocrystalline Ni-YSZ cermet anode for SOFC

    International Nuclear Information System (INIS)

    Priyatham, T.; Bauri, Ranjit

    2010-01-01

    Ni-YSZ cermet anode has been synthesized in one step using a simple and cost effective combustion synthesis process. The processed powder of NiO-YSZ is found to be nanocrystalline with crystallite sizes of 29 and 22 nm for NiO and YSZ respectively by X-ray diffraction and transmission electron microscopy analysis. X-ray diffraction analysis also shows that the precursor salts are converted to highly crystalline phases of NiO and YSZ (8 mol% Y 2 O 3 ) without any intermediate calcination step and no undesirable phases are present. Comparison with the X-ray diffraction pattern of a commercial YSZ sample shows that the process is also effective in maintaining a close compositional control. The microstructure of the sintered and reduced sample shows a well defined network of pores which is necessary for the effective functioning of the anode. The electrical conductivity as a function of temperature shows metallic behavior.

  10. Investigation of sulfur interactions on a conventional nickel-based solid oxide fuel cell anode during methane steam and dry reforming

    Science.gov (United States)

    Jablonski, Whitney S.

    Solid oxide fuel cells (SOFC) are an attractive energy source because they do not have undesirable emissions, are scalable, and are feedstock flexible, which means they can operate using a variety of fuel mixtures containing H2 and hydrocarbons. In terms of fuel flexibility, most potential fuel sources contain sulfur species, which severely poison the nickel-based anode. The main objective of this thesis is to systematically evaluate sulfur interactions on a conventional Ni/YSZ anode and compare sulfur poisoning during methane steam and dry reforming (SMR and DMR) to a conventional catalyst (Sud Chemie, Ni/K2O-CaAl2O4). Reforming experiments (SMR and DMR) were carried out in a packed bed reactor (PBR), and it was demonstrated that Ni/YSZ is much more sensitive to sulfur poisoning than Ni/K2O-CaAl2O4 as evidenced by the decline in activity to zero in under an hour for both SMR and DMR. Adsorption and desorption of H2S and SO2 on both catalysts was evaluated, and despite the low amount of accessible nickel on Ni/YSZ (14 times lower than Ni/K2O-CaAl2O4), it adsorbs 20 times more H2S and 50 times more SO2 than Ni/K 2O-CaAl2O4. A one-dimensional, steady state PBR model (DetchemPBED) was used to evaluate SMR and DMR under poisoning conditions using the Deutschmann mechanism and a recently published sulfur sub-mechanism. To fit the observed deactivation in the presence of 1 ppm H2S, the adsorption/desorption equilibrium constant was increased by a factor 16,000 for Ni/YSZ and 96 for Ni/K2O-CaAl2O4. A tubular SAE reactor was designed and fabricated for evaluating DMR in a reactor that mimics an SOFC. Evidence of hydrogen diffusion through a supposedly impermeable layer indicated that the tubular SAE reactor has a major flaw in which gases diffuse to unintended parts of the tube. It was also found to be extremely susceptible to coking which leads to cell failure even in operating regions that mimic real biogas. These problems made it impossible to validate the tubular SAE

  11. TAPE CALENDERING MANUFACTURING PROCESS FOR MULTILAYER THIN-FILM SOLID OXIDE FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Minh; Kurt Montgomery

    2004-10-01

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC during the Phases I and II under Contract DE-AC26-00NT40705 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Tape Calendering Manufacturing Process For Multilayer Thin-Film Solid Oxide Fuel Cells''. The main objective of this project was to develop the manufacturing process based on tape calendering for multilayer solid oxide fuel cells (SOFC's) using the unitized cell design concept and to demonstrate cell performance under specified operating conditions. Summarized in this report is the development and improvements to multilayer SOFC cells and the unitized cell design. Improvements to the multilayer SOFC cell were made in electrochemical performance, in both the anode and cathode, with cells demonstrating power densities of nearly 0.9 W/cm{sup 2} for 650 C operation and other cell configurations showing greater than 1.0 W/cm{sup 2} at 75% fuel utilization and 800 C. The unitized cell design was matured through design, analysis and development testing to a point that cell operation at greater than 70% fuel utilization was demonstrated at 800 C. The manufacturing process for both the multilayer cell and unitized cell design were assessed and refined, process maps were developed, forming approaches explored, and nondestructive evaluation (NDE) techniques examined.

  12. High-temperature conversion of methane on a composite gadolinia-doped ceria-gold electrode

    DEFF Research Database (Denmark)

    Marina, O.A.; Mogensen, Mogens Bjerg

    1999-01-01

    Direct electrochemical oxidation of methane was attempted on a gadolinia-doped ceria Ce(0.6)Gd(0.4)O(1.8) (CG4) electrode in a solid oxide fuel cell using a porous gold-CG4 mixture as current collector Gold is relatively inert to methane in contrast to other popular SOFC anode materials such as n......Direct electrochemical oxidation of methane was attempted on a gadolinia-doped ceria Ce(0.6)Gd(0.4)O(1.8) (CG4) electrode in a solid oxide fuel cell using a porous gold-CG4 mixture as current collector Gold is relatively inert to methane in contrast to other popular SOFC anode materials...... such as nickel and platinum. CG4 was found to exhibit a low electrocatalytic activity for methane oxidation as well as no significant reforming activity implying that the addition of an electrocatalyst or cracking catalyst to the CG4 anode is required for SOFC operating on methane. The methane conversion...... observed at the open-circuit potential and low anodic overpotentials seems to be due to thermal methane cracking in the gas phase and on the alumina surfaces in the cell housing. At high anodic overpotentials, at electrode potentials where oxygen evolution was expected to take place, the formation of CO(2...

  13. Inkjet printing and inkjet infiltration of functional coatings for SOFCs fabrication

    Directory of Open Access Journals (Sweden)

    Tomov Rumen I.

    2016-01-01

    Full Text Available Inkjet printing fabrication and modification of electrodes and electrolytes of SOFCs were studied. Electromagnetic print-heads were utilized to reproducibly dispense droplets of inks at rates of several kHz on demand. Printing parameters including pressure, nozzle opening time and drop spreading were studied in order to optimize the inks jetting and delivery. Scanning electron microscopy revealed highly conformal ~ 6-10 μm thick dense electrolyte layers routinely produced on cermet and metal porous supports. Open circuit voltages ranging from 0.95 to 1.01 V, and a maximum power density of ~180 mW.cm−2 were measured at 750 °C on Ni-8YSZ/YSZ/LSM single cell 50×50 mm in size. The effect of anode and cathode microstructures on the electrochemical performance was investigated. Two - step fabrication of the electrodes using inkjet printing infiltration was implemented. In the first step the porous electrode scaffold was created printing suspension composite inks. During the second step inkjet printing infiltration was utilized for controllable loading of active elements and a formation of nano-grid decorations on the scaffolds radically reducing the activation polarization losses of both electrodes. Symmetrical cells of both types were characterized by impedance spectroscopy in order to reveal the relation between the microstructure and the electrochemical performance.

  14. Performance of a novel type of electrolyte-supported solid oxide fuel cell with honeycomb structure

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Morales, Juan Carlos; Savvin, Stanislav N.; Nunez, Pedro [Departmento de Quimica Inorganica, Universidad de La Laguna, 38200 Tenerife (Spain); Marrero-Lopez, David [Departamento de Fisica Aplicada I, Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, Juan; Canales-Vazquez, Jesus [Instituto de Energias Renovables-Universidad de Castilla la Mancha, 02006 Albacete (Spain); Roa, Joan Josep; Segarra, Merce [DIOPMA, Departamento de Ciencia de los Materiales e Ing. Metalurgica, 08028 Barcelona (Spain)

    2010-01-15

    A novel design, alternative to the conventional electrolyte-supported solid oxide fuel cell (SOFC) is presented. In this new design, a honeycomb-electrolyte is fabricated from hexagonal cells, providing high mechanical strength to the whole structure and supporting the thin layer used as electrolyte of a SOFC. This new design allows a reduction of {proportional_to}70% of the electrolyte material and it renders modest performances over 320 mW cm{sup -2} but high volumetric power densities, i.e. 1.22 W cm{sup -3} under pure CH{sub 4} at 900 C, with a high OCV of 1.13 V, using the standard Ni-YSZ cermet as anode, Pt as cathode material and air as the oxidant gas. (author)

  15. Improving the Performance of SOFC Anodes by Decorating Perovskite with Ni Nanoparticles

    KAUST Repository

    Boulfrad, S.; Cassidy, M.; Traversa, Enrico; Irvine, J. T. S.

    2013-01-01

    In this work (La0.75Sr0.25)0.97Cr0.5Mn0.5O3 (LSCM) perovskite powders were pre-coated with 5 wt% nickel and mixed with different amounts of CGO for testing as anode materials under 3% wet H2. By using scanning transmission electron microscopy (STEM) with X-ray energy dispersive spectroscopy (EDS), we demonstrated that Ni forms a solid solution in the perovkite phase under oxidizing atmosphere and exsolves in form of nanoparticles under reducing atmospheres. The presence of the catalyst nanoparticles led to a decrease in the anodic activation energy by half and thus the polarization resistance was dropped by 60% at 800¢ªC. The effect of CGO amount will be also discussed.

  16. Improving the Performance of SOFC Anodes by Decorating Perovskite with Ni Nanoparticles

    KAUST Repository

    Boulfrad, S.

    2013-10-07

    In this work (La0.75Sr0.25)0.97Cr0.5Mn0.5O3 (LSCM) perovskite powders were pre-coated with 5 wt% nickel and mixed with different amounts of CGO for testing as anode materials under 3% wet H2. By using scanning transmission electron microscopy (STEM) with X-ray energy dispersive spectroscopy (EDS), we demonstrated that Ni forms a solid solution in the perovkite phase under oxidizing atmosphere and exsolves in form of nanoparticles under reducing atmospheres. The presence of the catalyst nanoparticles led to a decrease in the anodic activation energy by half and thus the polarization resistance was dropped by 60% at 800¢ªC. The effect of CGO amount will be also discussed.

  17. Infiltration of SOFC Stacks: Evaluation of the Electrochemical Performance Enhancement and the Underlying Changes in the Microstructure

    DEFF Research Database (Denmark)

    Kiebach, Wolff-Ragnar; Zielke, Philipp; Høgh, Jens Valdemar Thorvald

    2016-01-01

    Experimental SOFC stacks with 10 SOFCs (LSM-YSZ/YSZ/Ni-YSZ) were infiltrated with CGO and Ni-CGO on the air and fuel side, respectively in an attempt to counter degradation and improve the output. The electrochemical performance of each cell was characterized (i) before infiltration, (ii) after i...

  18. Mechanistic Enhancement of SOFC Cathode Durability

    Energy Technology Data Exchange (ETDEWEB)

    Wachsman, Eric [Univ. of Maryland, College Park, MD (United States)

    2016-02-01

    Durability of solid oxide fuel cells (SOFC) under “real world” conditions is an issue for commercial deployment. In particular cathode exposure to moisture, CO2, Cr vapor (from interconnects and BOP), and particulates results in long-term performance degradation issues. Here, we have conducted a multi-faceted fundamental investigation of the effect of these contaminants on cathode performance degradation mechanisms in order to establish cathode composition/structures and operational conditions to enhance cathode durability.

  19. Evaluation of apatite silicates as solid oxide fuel cell electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Martin-Sedeno, M.C.; Aranda, M.A.G. [Dpto. de Quimica Inorganica, Universidad Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C.; Nunez, P. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Ramos-Barrado, J.R. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain)

    2010-05-01

    Apatite-type silicates have been considered as promising electrolytes for Solid Oxide Fuel Cells (SOFC); however studies on the potential use of these materials in SOFC devices have received relatively little attention. The lanthanum silicate with composition La{sub 10}Si{sub 5.5}Al{sub 0.5}O{sub 26.75} has been evaluated as electrolyte with the electrode materials commonly used in SOFC, i.e. manganite, ferrite and cobaltite as cathode materials and NiO-CGO composite, chromium-manganite and Sr{sub 2}MgMoO{sub 6} as anode materials. Chemical compatibility, area-specific resistance and fuel cell studies have been performed. X-ray powder diffraction (XRPD) analysis did not reveal any trace of reaction products between the apatite electrolyte and most of the aforementioned electrode materials. However, the area-specific polarisation resistance (ASR) of these electrodes in contact with apatite electrolyte increased significantly with the sintering temperature, indicating reactivity at the electrolyte/electrode interface. On the other hand, the ASR values are significantly improved using a ceria buffer layer between the electrolyte and electrode materials to prevent reactivity. Maximum power densities of 195 and 65 mWcm{sup -2} were obtained at 850 and 700 C, respectively in H{sub 2} fuel, using an 1 mm-thick electrolyte, a NiO-Ce{sub 0.8}Gd{sub 0.2}O{sub 1.9} composite as anode and La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} as cathode materials. This fuel cell was tested for 100 h in 5%H{sub 2}-Ar atmosphere showing stable performance. (author)

  20. Performance comparison of low-temperature direct alcohol fuel cells with different anode catalysts

    Science.gov (United States)

    Zhou, W. J.; Zhou, B.; Li, W. Z.; Zhou, Z. H.; Song, S. Q.; Sun, G. Q.; Xin, Q.; Douvartzides, S.; Goula, M.; Tsiakaras, P.

    Low-temperature polymer electrolyte membrane fuel cells directly fed by methanol and ethanol were investigated employing carbon supported Pt, PtSn and PtRu as anode catalysts, respectively. Employing Pt/C as anode catalyst, both direct methanol fuel cell (DMFC) and direct ethanol fuel cell (DEFC) showed poor performances even in presence of high Pt loading on anode. It was found that the addition of Ru or Sn to the Pt dramatically enhances the electro-oxidation of both methanol and ethanol. It was also found that the single cell adopting PtRu/C as anode shows better DMFC performance, while PtSn/C catalyst shows better DEFC performance. The single fuel cell using PtSn/C as anode catalyst at 90 °C shows similar power densities whenever fueled by methanol or ethanol. The cyclic voltammetry (CV) and single fuel cell tests indicated that PtRu is more suitable for DMFC while PtSn is more suitable for DEFC.

  1. Method for in situ carbon deposition measurement for solid oxide fuel cells

    Science.gov (United States)

    Kuhn, J.; Kesler, O.

    2014-01-01

    Previous methods to measure carbon deposition in solid oxide fuel cell (SOFC) anodes do not permit simultaneous electrochemical measurements. Electrochemical measurements supplemented with carbon deposition quantities create the opportunity to further understand how carbon affects SOFC performance and electrochemical impedance spectra (EIS). In this work, a method for measuring carbon in situ, named here as the quantification of gasified carbon (QGC), was developed. TGA experiments showed that carbon with a 100 h residence time in the SOFC was >99.8% gasified. Comparison of carbon mass measurements between the TGA and QGC show good agreement. In situ measurements of carbon deposition in SOFCs at varying molar steam/carbon ratios were performed to further validate the QGC method, and suppression of carbon deposition with increasing steam concentration was observed, in agreement with previous studies. The technique can be used to investigate in situ carbon deposition and gasification behavior simultaneously with electrochemical measurements for a variety of fuels and operating conditions, such as determining conditions under which incipient carbon deposition is reversible.

  2. Transient performance of integrated SOFC system including spatial temperature control

    OpenAIRE

    Mueller, F; Fardadi, M; Shaffer, B; Brouwer, J; Jabbari, F

    2010-01-01

    Spatial temperature feedback control has been developed for a simulated integrated non-pressurized simple cycle solid oxide fuel cell (SOFC) system. The fuel cell spatial temperature feedback controller is based on (1) feed-forward set-points that minimize temperature variation in the fuel cell electrode-electrolyte solid temperature profile for the system operating power range, and (2) decentralized proportional-integral based feedback to maintain the fuel cell spatial temperature profile du...

  3. Internal reforming characteristics of cermet supported solid oxide fuel cell using yttria stabilized zirconia fed with partially reformed methane

    Science.gov (United States)

    Momma, Akihiko; Takano, Kiyonami; Tanaka, Yohei; Negishi, Akira; Kato, Ken; Nozaki, Ken; Kato, Tohru; Ichigi, Takenori; Matsuda, Kazuyuki; Ryu, Takashi

    In order to investigate the internal reforming characteristics in a cermet supported solid oxide fuel cell (SOFC) using YSZ as the electrolyte, the concentration profiles of the gaseous species along the gas flow direction in the anode were measured. Partially reformed methane using a pre-reformer kept at a constant temperature is supplied to the center of the cell which is operated with a seal-less structure at the gas outlet. The anode gas is sucked in via silica capillaries to the initially evacuated gas tanks. The process is simultaneously carried out using five sampling ports. The sampled gas is analyzed by a gas chromatograph. Most of the measurements are made at the cell temperature (T cell) of 750 °C and at various temperatures of the pre-reformer (T ref) with various fuel utilizations (U f) of the cell. The composition of the fuel at the inlet of the anode was confirmed to be almost the same as that theoretically calculated assuming equilibrium at the temperature of the pre-reformer. The effect of internal reforming in the anode is clearly observed as a steady decrease in the methane concentration along the flow axis. The effect of the water-gas shift reaction is also observed as a decrease in the CO 2 concentration and an increase of CO concentration around the gas inlet region, as the water-gas shift reaction inversely proceeds when T cell is higher than T ref. The diffusion of nitrogen from the seal-less outermost edge is observed, and the diffusion is confirmed to be more significant as U f decreases. The observations are compared with the results obtained by the SOFC supported by lanthanum gallate electrolyte. With respect to the internal reforming performance, the cell investigated here is found to be more effective when compared to the previously reported electrolyte supported cell.

  4. Performance of lithium alloy/lithium and calcium/lithium anodes in thionyl chloride cells

    Energy Technology Data Exchange (ETDEWEB)

    Keister, P.; Greenwood, J.M.; Holmes, C.F.; Mead, R.T.

    1985-08-01

    A laminar composite anode construction comprising an inner metal completely surrounded by Li foil was studied as a means of obtaining an end-of-life indicator in a thionyl chloride cell. Inner metals of Ca, 14-2.9 at.% Ca in Li alloys, and 6.7-2.1 at.% Mg in Li alloys were evaluated. Discharge characteristics of cells using these sandwich anodes as well as cells containing the inner anode material alone were determined. It was concluded that cells made with inner anode materials of Ca and Ca/Li alloys containing more than 7 at.% Ca showed promise as a means of obtaining a reliable end-of-life indication. (orig.).

  5. Structural analysis of nickel doped cerium oxide catalysts for fuel reforming in solid oxide fuel cells

    Science.gov (United States)

    Cavendish, Rio

    As world energy demands increase, research into more efficient energy production methods has become imperative. Heterogeneous catalysis and nanoscience are used to promote chemical transformations important for energy production. These concepts are important in solid oxide fuel cells (SOFCs) which have attracted attention because of their potential to provide an efficient and environmentally favorable power generation system. The SOFC is also fuel-flexible with the ability to run directly on many fuels other than hydrogen. Internal fuel reforming directly in the anode of the SOFC would greatly reduce the cost and complexity of the device. Methane is the simplest hydrocarbon and a main component in natural gas, making it useful when testing catalysts on the laboratory scale. Nickel (Ni) and gadolinium (Gd) doped ceria (CeO 2) catalysts for potential use in the SOFC anode were synthesized with a spray drying method and tested for catalytic performance using partial oxidation of methane and steam reforming. The relationships between catalytic performance and structure were then investigated using X-ray diffraction, transmission electron microscopy, and environmental transmission electron microscopy. The possibility of solid solutions, segregated phases, and surface layers of Ni were explored. Results for a 10 at.% Ni in CeO2 catalyst reveal a poor catalytic behavior while a 20 at.% Ni in CeO2 catalyst is shown to have superior activity. The inclusion of both 10 at.% Gd and 10 at.% Ni in CeO2 enhances the catalytic performance. Analysis of the presence of Ni in all 3 samples reveals Ni heterogeneity and little evidence for extensive solid solution doping. Ni is found in small domains throughout CeO2 particles. In the 20 at.% Ni sample a segregated, catalytically active NiO phase is observed. Overall, it is found that significant interaction between Ni and CeO2 occurs that could affect the synthesis and functionality of the SOFC anode.

  6. Development of perovskite cathodes for solid oxide fuel cells (SOFC); Desenvolvimento de catodos de perovskitas para celula a combustivel solido de eletrolito solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Perez, J. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica], e-mail: joelma@iq.unesp.br; Pereira, J.T.; Saeki, M.J. [UNESP, Bauru, SP (Brazil). Faculdade de Ciencias

    2006-07-01

    Solid Oxide Fuel Cells (SOFC) are energy conversion systems of great interest for industrial applications because they present a high efficiency for energy generation and several advantages for the environment. In this work, perovskite type oxides La{sub 085}Sr{sub 0,15}MnO{sub 3}, La{sub 0,7} Sr{sub 0,3}MnO{sub 3}, La{sub 0,6}Sr{sub 0,4}MnO{sub 3}, La{sub 0,85}Sr{sub 0,15}CoO{sub 3}, La{sub 0,7}Sr{sub 0,3}CoO{sub 3}, La{sub 0,6}Sr{sub 0,4}CoO{sub 3}, La{sub 0.6}Sr{sub 0,4}Fe{sub 0,8}Co{sub 0,2}O{sub 3} e La{sub 0.6}Sr{sub 0,4}Fe{sub 0,4}Co{sub 0,6}O{sub 3} were prepared by a polymeric method with the purpose of using them as cathodes in SOFCs. The electrochemical cell was mounted utilizing YSZ (ZrO{sub 2} - 8 mol%Y{sub 2}O{sub 3}) disks as electrolyte, where a paste containing Pt was calcined onto one face while the other one was covered with the oxide materials synthesized ('screen printing'). The oxide materials prepared were characterized by X-ray diffraction, transmission electronic microscopy and thermogravimetry. The oxygen reduction reaction was studied by taking polarization curves in oxygen and/or air (800 deg C a 950 deg C). The best performance was obtained for 15 {mu}m thickness electrodes La{sub 0.6}Sr{sub 0,4}MnO{sub 3} and La{sub 0.6}Sr{sub 0,4}MnO{sub 3} with addition of dispersed Pt. (author)

  7. Spontaneous oscillations of cell voltage, power density, and anode exit CO concentration in a PEM fuel cell.

    Science.gov (United States)

    Lu, Hui; Rihko-Struckmann, Liisa; Sundmacher, Kai

    2011-10-28

    The spontaneous oscillations of the cell voltage and output power density of a PEMFC (with PtRu/C anode) using CO-containing H(2) streams as anodic fuels have been observed during galvanostatic operating. It is ascribed to the dynamic coupling of the CO adsorption (poisoning) and the electrochemical CO oxidation (reactivating) processes in the anode chamber of the single PEMFC. Accompanying the cell voltage and power density oscillations, the discrete CO concentration oscillations at the anode outlet of the PEMFC were also detected, which directly confirms the electrochemical CO oxidation taking place in the anode chamber during galvanostatic operating. This journal is © the Owner Societies 2011

  8. A Brief Description of High Temperature Solid Oxide Fuel Cell’s Operation, Materials, Design, Fabrication Technologies and Performance

    Directory of Open Access Journals (Sweden)

    Muneeb Irshad

    2016-03-01

    Full Text Available Today’s world needs highly efficient systems that can fulfill the growing demand for energy. One of the promising solutions is the fuel cell. Solid oxide fuel cell (SOFC is considered by many developed countries as an alternative solution of energy in near future. A lot of efforts have been made during last decade to make it commercial by reducing its cost and increasing its durability. Different materials, designs and fabrication technologies have been developed and tested to make it more cost effective and stable. This article is focused on the advancements made in the field of high temperature SOFC. High temperature SOFC does not need any precious catalyst for its operation, unlike in other types of fuel cell. Different conventional and innovative materials have been discussed along with properties and effects on the performance of SOFC’s components (electrolyte anode, cathode, interconnect and sealing materials. Advancements made in the field of cell and stack design are also explored along with hurdles coming in their fabrication and performance. This article also gives an overview of methods required for the fabrication of different components of SOFC. The flexibility of SOFC in terms fuel has also been discussed. Performance of the SOFC with varying combination of electrolyte, anode, cathode and fuel is also described in this article.

  9. A methodology for thermodynamic simulation of high temperature, internal reforming fuel cell systems

    Science.gov (United States)

    Matelli, José Alexandre; Bazzo, Edson

    This work presents a methodology for simulation of fuel cells to be used in power production in small on-site power/cogeneration plants that use natural gas as fuel. The methodology contemplates thermodynamics and electrochemical aspects related to molten carbonate and solid oxide fuel cells (MCFC and SOFC, respectively). Internal steam reforming of the natural gas hydrocarbons is considered for hydrogen production. From inputs as cell potential, cell power, number of cell in the stack, ancillary systems power consumption, reformed natural gas composition and hydrogen utilization factor, the simulation gives the natural gas consumption, anode and cathode stream gases temperature and composition, and thermodynamic, electrochemical and practical efficiencies. Both energetic and exergetic methods are considered for performance analysis. The results obtained from natural gas reforming thermodynamics simulation show that the hydrogen production is maximum around 700 °C, for a steam/carbon ratio equal to 3. As shown in the literature, the found results indicate that the SOFC is more efficient than MCFC.

  10. Analysis of Gas Leakage and Current Loss of Solid Oxide Fuel Cells by Screen Printing

    DEFF Research Database (Denmark)

    Jia, Chuan; Han, Minfang; Chen, Ming

    2017-01-01

    operating life and lead to performance degradation. The planar anode-supported Ni-YSZ|YSZ|LSCF SOFC was chosen as the research object, with the cell size of 12cm×12cm and the effective area of 100cm2, and the holder is made of 99% purity of Al2O3 ceramic material, in order to eliminate the influence of Cr...

  11. Enhancing hybrid direct carbon fuel cell anode performance using Ag2O

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Ippolito, Davide; Kammer Hansen, Kent

    2015-01-01

    A hybrid-direct carbon fuel cell (HDCFC), consisting of a molten slurry of solid carbon black and (Li-K)2CO3 added to the anode chamber of a solid oxide fuel cell, was characterized using current-potential-power density curves, electrochemical impedance spectroscopy, and cyclic voltammetry. Two...... types of experimental setups were employed in this study, an anode-supported full cell configuration (two electrodes, two atmospheres setup) and a 3-electrode electrolyte-supported half-cell setup (single atmosphere). Anode processes with and without catalysts were investigated as a function...... of temperature (700-800 °C) and anode sweep gas (N2, 4-100% CO2 in N2-CO2). It was shown that the addition of silver based catalysts (Ag, Ag2O, Ag2CO3) into the carbon-carbonate slurry enhanced the performance of the HDCFC....

  12. Effect of load transients on SOFC operation—current reversal on loss of load

    Science.gov (United States)

    Gemmen, Randall S.; Johnson, Christopher D.

    The dynamics of solid oxide fuel cell (SOFC) operation have been considered previously, but mainly through the use of one-dimensional codes applied to co-flow fuel cell systems. In this paper several geometries are considered, including cross-flow, co-flow, and counter-flow. The details of the model are provided, and the model is compared with some initial experimental data. For parameters typical of SOFC operation, a variety of transient cases are investigated, including representative load increase and decrease and system shutdown. Of particular note for large load decrease conditions (e.g., shutdown) is the occurrence of reverse current over significant portions of the cell, starting from the moment of load loss up to the point where equilibrated conditions again provide positive current. Consideration is given as to when such reverse current conditions might most significantly impact the reliability of the cell.

  13. Electrical Generation for More-Electric Aircraft Using Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Whyatt, Greg A.; Chick, Lawrence A.

    2012-04-01

    This report examines the potential for Solid-Oxide Fuel Cells (SOFC) to provide electrical generation on-board commercial aircraft. Unlike a turbine-based auxiliary power unit (APU) a solid oxide fuel cell power unit (SOFCPU) would be more efficient than using the main engine generators to generate electricity and would operate continuously during flight. The focus of this study is on more-electric aircraft which minimize bleed air extraction from the engines and instead use electrical power obtained from generators driven by the main engines to satisfy all major loads. The increased electrical generation increases the potential fuel savings obtainable through more efficient electrical generation using a SOFCPU. However, the weight added to the aircraft by the SOFCPU impacts the main engine fuel consumption which reduces the potential fuel savings. To investigate these relationships the Boeing 787­8 was used as a case study. The potential performance of the SOFCPU was determined by coupling flowsheet modeling using ChemCAD software with a stack performance algorithm. For a given stack operating condition (cell voltage, anode utilization, stack pressure, target cell exit temperature), ChemCAD software was used to determine the cathode air rate to provide stack thermal balance, the heat exchanger duties, the gross power output for a given fuel rate, the parasitic power for the anode recycle blower and net power obtained from (or required by) the compressor/expander. The SOFC is based on the Gen4 Delphi planar SOFC with assumed modifications to tailor it to this application. The size of the stack needed to satisfy the specified condition was assessed using an empirically-based algorithm. The algorithm predicts stack power density based on the pressure, inlet temperature, cell voltage and anode and cathode inlet flows and compositions. The algorithm was developed by enhancing a model for a well-established material set operating at atmospheric pressure to reflect the

  14. Characterization of ceria-based SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Doshi, R.; Routbort, J.; Krumpelt, M. [Argonne National Lab., IL (United States)

    1996-12-31

    Solid Oxide Fuel Cells (SOFCs) operating at low temperatures (500-700{degrees}C) offer many advantages over the conventional zirconia-based fuel cells operating at higher temperatures. Reduced operating temperatures result in: (1) Application of metallic interconnects with reduced oxidation problems (2) Reduced time for start-up and lower energy consumption to reach operating temperatures (3) Increased thermal cycle ability for the cell structure due to lower thermal stresses of expansion mismatches. While this type of fuel cell may be applied to stationary applications, mobile applications require the ability for rapid start-up and frequent thermal cycling. Ceria-based fuel cells are currently being developed in the U.K. at Imperial College, Netherlands at ECN, and U.S.A. at Ceramatec. The cells in each case are made from a doped ceria electrolyte and a La{sub 1-x}Sr{sub x}Co{sub 1-y}Fe{sub y}O{sub 3} cathode.

  15. Ni-YSZ cermet substrate supported thin SDC and YSZ+SDC bi-layer SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.; Robertson, M.; Deces-Petit, C.; Xie, Y.; Hui, R.; Yick, S.; Styles, E.; Roller, J.; Kesler, O.; Qu, W.; Jankovic, J.; Tang, Z.; Perednis, D.; Maric, R.; Ghosh, D. [National Research Council of Canada, Vancouver, BC (Canada). Inst. for Fuel Cell Innovation

    2005-07-01

    One of the disadvantages of a ceria-based electrolyte is that it becomes a mixed conductor at anode conditions, which causes cell voltage loss and fuel efficiency loss due to internal shorting. Chemical and mechanical stability is another concern for long-term service. To lower manufacturing costs, efforts have been made to bring proven semiconductor manufacturing technology to Solid Oxide Fuel Cells (SOFCs). This study employed Tape casting of cermet substrates, Screen-printing of functional layers and Co-firing of cell components (TSC) to fabricate nickel (Ni)-cermet supported cells with mainly ceria-based thin electrolytes. Ni-Yttria-Stabilized Zirconia (YSZ) cermet supported cell with Samaria Doped Ceria (SDC) single layer electrolytes and YSZ+SDC bi-layer electrolytes were successfully developed for low-temperature performance characterization. The elemental distribution at the cell interface was mapped and the electrochemical performance of the cells was recorded. Many high-Zr-content micro-islands were found on the thin SDC surface. The influence of co-firing temperature and thin-film preparation methods on the Zr-islands' appearance was also investigated. Using in-situ sintered cathodes, high performance of the SDC cells was obtained. It was concluded that the bi-layer cells did show higher Open Circuit Voltage (OCV) values, with 1180 mW/cm{sup 2} at 650 degrees C, as well as good performance at 700-800 degrees C, with near OCV value. However, their performance was much lower than those of the SDC cells at low operating temperature. Zr-micro-islands formation on the SDC electrolyte was observed and investigated. 6 refs., 5 tabs., 7 figs.

  16. Techno-Economic Feasibility of Highly Efficient Cost-Effective Thermoelectric-SOFC Hybrid Power Generation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Jifeng Zhang; Jean Yamanis

    2007-09-30

    Solid oxide fuel cell (SOFC) systems have the potential to generate exhaust gas streams of high temperature, ranging from 400 to 800 C. These high temperature gas streams can be used for additional power generation with bottoming cycle technologies to achieve higher system power efficiency. One of the potential candidate bottoming cycles is power generation by means of thermoelectric (TE) devices, which have the inherent advantages of low noise, low maintenance and long life. This study was to analyze the feasibility of combining coal gas based SOFC and TE through system performance and cost techno-economic modeling in the context of multi-MW power plants, with 200 kW SOFC-TE module as building blocks. System and component concepts were generated for combining SOFC and TE covering electro-thermo-chemical system integration, power conditioning system (PCS) and component designs. SOFC cost and performance models previously developed at United Technologies Research Center were modified and used in overall system analysis. The TE model was validated and provided by BSST. The optimum system in terms of energy conversion efficiency was found to be a pressurized SOFC-TE, with system efficiency of 65.3% and cost of $390/kW of manufacturing cost. The pressurization ratio was approximately 4 and the assumed ZT of the TE was 2.5. System and component specifications were generated based on the modeling study. The major technology and cost barriers for maturing the system include pressurized SOFC stack using coal gas, the high temperature recycle blowers, and system control design. Finally, a 4-step development roadmap is proposed for future technology development, the first step being a 1 kW proof-of-concept demonstration unit.

  17. Binder Jetting: A Novel Solid Oxide Fuel-Cell Fabrication Process and Evaluation

    Science.gov (United States)

    Manogharan, Guha; Kioko, Meshack; Linkous, Clovis

    2015-03-01

    With an ever-growing concern to find a more efficient and less polluting means of producing electricity, fuel cells have constantly been of great interest. Fuel cells electrochemically convert chemical energy directly into electricity and heat without resorting to combustion/mechanical cycling. This article studies the solid oxide fuel cell (SOFC), which is a high-temperature (100°C to 1000°C) ceramic cell made from all solid-state components and can operate under a wide range of fuel sources such as hydrogen, methanol, gasoline, diesel, and gasified coal. Traditionally, SOFCs are fabricated using processes such as tape casting, calendaring, extrusion, and warm pressing for substrate support, followed by screen printing, slurry coating, spray techniques, vapor deposition, and sputter techniques, which have limited control in substrate microstructure. In this article, the feasibility of engineering the porosity and configuration of an SOFC via an additive manufacturing (AM) method known as binder jet printing was explored. The anode, cathode and oxygen ion-conducting electrolyte layers were fabricated through AM sequentially as a complete fuel cell unit. The cell performance was measured in two modes: (I) as an electrolytic oxygen pump and (II) as a galvanic electricity generator using hydrogen gas as the fuel. An analysis on influence of porosity was performed through SEM studies and permeability testing. An additional study on fuel cell material composition was conducted to verify the effects of binder jetting through SEM-EDS. Electrical discharge of the AM fabricated SOFC and nonlinearity of permeability tests show that, with additional work, the porosity of the cell can be modified for optimal performance at operating flow and temperature conditions.

  18. Impedance analysis of a disk-type SOFC using doped lanthanum gallate under power generation

    Science.gov (United States)

    Kato, Tohru; Nozaki, Ken; Negishi, Akira; Kato, Ken; Monma, Akihiko; Kaga, Yasuo; Nagata, Susumu; Takano, Kiyonami; Inagaki, Toru; Yoshida, Hiroyuki; Hosoi, Kei; Hoshino, Koji; Akbay, Taner; Akikusa, Jun

    Impedance measurements were carried out under practical power generation conditions in a disk-type SOFC, which may be utilized as a small-scale power generator. The tested cell was composed of doped lanthanum gallate (La 0.8Sr 0.2Ga 0.8Mg 0.15Co 0.05O 3- δ) as the electrolyte, Sm 0.5Sr 0.5CoO 3 as the cathode electrode and Ni/Ce 0.8Sm 0.2O 2 cermet as the anode electrode. The cell impedance was measured between 10 mHz and 10 kHz by varying the fuel utilization and gas flow rate and plotted in complex impedance diagrams. The observed impedance shows a large semi-circular pattern on the low frequency side. The semi-circular impedance, having a noticeably low characteristic frequency between 0.13 and 0.4 Hz, comes from the change in gas composition, originally caused by the cell reaction. The change in impedance with the fuel utilization (load current) and the gas flow rate agreed qualitatively well with the theoretical predictions from a simulation. This impedance was dominant under high fuel-utilization power-generation conditions. The impedance, which described the activation polarizations in the electrode reactions, was comparatively small and scarcely changed with the change in fuel utilization (load current) and gas flow rate.

  19. Diesel Fueled SOFC for Class 7/Class 8 On-Highway Truck Auxiliary Power

    Energy Technology Data Exchange (ETDEWEB)

    Vesely, Charles John-Paul [Cummins Power Generation; Fuchs, Benjamin S. [Cummins Power Generation; Booten, Chuck W. [Protonex Technology, LLC

    2010-03-31

    The following report documents the progress of the Cummins Power Generation (CPG) Diesel Fueled SOFC for Class 7/Class 8 On-Highway Truck Auxiliary Power (SOFC APU) development and final testing under the U.S. Department of Energy (DOE) Energy Efficiency and Renewable Energy (EERE) contract DE-FC36-04GO14318. This report overviews and summarizes CPG and partner development leading to successful demonstration of the SOFC APU objectives and significant progress towards SOFC commercialization. Significant SOFC APU Milestones: Demonstrated: Operation meeting SOFC APU requirements on commercial Ultra Low Sulfur Diesel (ULSD) fuel. SOFC systems operating on dry CPOX reformate. Successful start-up and shut-down of SOFC APU system without inert gas purge. Developed: Low cost balance of plant concepts and compatible systems designs. Identified low cost, high volume components for balance of plant systems. Demonstrated efficient SOFC output power conditioning. Demonstrated SOFC control strategies and tuning methods.

  20. Performance and life time test on a 5 kW SOFC system for distributed cogeneration

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, Rosa; De Biase, Sabrina; Ginocchio, Stefano [Edison S.p.A, Via Giorgio La Pira, 2, 10028 Trofarello (Italy); Bedogni, Stefano; Montelatici, Lorenzo [Edison S.p.A, Foro Bonaparte 31, 20121 Milano (Italy)

    2008-06-15

    Edison R and D Centre is committed to test a wide range of commercial and prototypal fuel cell systems. The activities aim to evaluate the available state of the art of these technologies and their maturity for the relevant market. The laboratory is equipped with ad hoc test benches designed to study single cells, stacks and systems. The characterization of commercial and new generation PEMFC, also for high temperatures (160 C), together with the analysis of the behaviour of SOFC represent the core activities of the laboratory. On January 2007 a new 5 kW SOFC system supplied by Acumentrics was installed. The claimed electrical power output is 5 kW and thermal power is 3 kW. The aim of the test is the achievement of technical and economical assessment for future applications of small SOFC plants for distributed cogeneration. Performance and life time test of the system are shown. (author)

  1. Thermodynamic and Thermoeconomic investigation of an Integrated Gasification SOFC and Stirling Engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2013-01-01

    Thermodynamic and thermoeconomic investigation of a small scale Integrated Gasification Solid Oxide Fuel Cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120kW have been performed. Woodchips are used as gasification feedstock to produce syngas which......-product and the cost of hot water was found to be 0.0214$/kWh. When compared to other renewable systems at similar scale, it shows that if both SOFC and Stirling engine technology emerges enter commercialization phase, then they can deliver electricity at a cost rate which is competitive with corresponding renewable...

  2. Synthesis and electrochemical performances of LiNiCuZn oxides as anode and cathode catalyst for low temperature solid oxide fuel cell.

    Science.gov (United States)

    Jing, Y; Qin, H; Liu, Q; Singh, M; Zhu, B

    2012-06-01

    Low temperature solid oxide fuel cell (LTSOFC, 300-600 degrees C) is developed with advantages compared to conventional SOFC (800-1000 degrees C). The electrodes with good catalytic activity, high electronic and ionic conductivity are required to achieve high power output. In this work, a LiNiCuZn oxides as anode and cathode catalyst is prepared by slurry method. The structure and morphology of the prepared LiNiCuZn oxides are characterized by X-ray diffraction and field emission scanning electron microscopy. The LiNiCuZn oxides prepared by slurry method are nano Li0.28Ni0.72O, ZnO and CuO compound. The nano-crystallites are congregated to form ball-shape particles with diameter of 800-1000 nm. The LiNiCuZn oxides electrodes exhibits high ion conductivity and low polarization resistance to hydrogen oxidation reaction and oxygen reduction reaction at low temperature. The LTSOFC using the LiNiCuZn oxides electrodes demonstrates good cell performance of 1000 mW cm(-2) when it operates at 470 degrees C. It is considered that nano-composite would be an effective way to develop catalyst for LTSOFC.

  3. On the nanostructuring and catalytic promotion of intermediate temperature solid oxide fuel cell (IT-SOFC) cathodes

    Science.gov (United States)

    Serra, José M.; Buchkremer, Hans-Peter

    Solid oxide fuel cells (SOFCs) are highly efficient energy converters for both stationary and mobile purposes. However, their market introduction still demands the reduction of manufacture costs and one possible way to reach this goal is the decrease of the operating temperatures, which entails the improvement of the cathode electrocatalytic properties. An ideal cathode material may have mixed ionic and electronic conductivity as well as proper catalytic properties. Nanostructuring and catalytic promotion of mixed conducting perovskites (e.g. La 0.58Sr 0.4Fe 0.8Co 0.2O 3- δ) seem to be promising approaches to overcoming cathode polarization problems and are briefly illustrated here. The preparation of nanostructured cathodes with relatively high surface area and enough thermal stability enables to improve the oxygen exchange rate and therefore the overall SOFC performance. A similar effect was obtained by catalytic promoting the perovskite surface, allowing decoupling the catalytic and ionic-transport properties in the cathode design. Noble metal incorporation may improve the reversibility of the reduction cycles involved in the oxygen reduction. Under the cathode oxidizing conditions, Pd seems to be partially dissolved in the perovskite structure and as a result very well dispersed.

  4. Effects of the Molybdenum Oxide/Metal Anode Interfaces on Inverted Polymer Solar Cells

    International Nuclear Information System (INIS)

    Wu Jiang; Guo Xiao-Yang; Xie Zhi-Yuan

    2012-01-01

    Inverted polymer solar cells with molybdenum oxide (MoO 3 ) as an anode buffer layer and different metals (Al or Ag) as anodes are studied. It is found that the inverted cell with a top Ag anode demonstrates enhanced charge collection and higher power conversion efficiency (PCE) compared to the cell with a top Al anode. An 18% increment of PCE is obtained by replacing Al with Ag as the top anode. Further studies show that an interfacial dipole pointing from MoO 3 to Al is formed at MoO 3 /Al interfaces due to electron transfer from Al to MoO 3 while this phenomenon cannot be observed at MoO 3 /Ag interfaces. It is speculated that the electric field at the MoO 3 /Al interface would hinder hole extraction, and hence reduce the short-circuit current

  5. Hydrogen oxidation mechanisms on Ni/yttria stabilized zirconia anodes: Separation of reaction pathways by geometry variation of pattern electrodes

    Science.gov (United States)

    Doppler, M. C.; Fleig, J.; Bram, M.; Opitz, A. K.

    2018-03-01

    Nickel/yttria stabilized zirconia (YSZ) electrodes are affecting the overall performance of solid oxide fuel cells (SOFCs) in general and strongly contribute to the cell resistance in case of novel metal supported SOFCs in particular. The electrochemical fuel conversion mechanisms in these electrodes are, however, still only partly understood. In this study, micro-structured Ni thin film electrodes on YSZ with 15 different geometries are utilized to investigate reaction pathways for the hydrogen electro-oxidation at Ni/YSZ anodes. From electrodes with constant area but varying triple phase boundary (TPB) length a contribution to the electro-catalytic activity is found that does not depend on the TPB length. This additional activity could clearly be attributed to a yet unknown reaction pathway scaling with the electrode area. It is shown that this area related pathway has significantly different electrochemical behavior compared to the TPB pathway regarding its thermal activation, sulfur poisoning behavior, and H2/H2O partial pressure dependence. Moreover, possible reaction mechanisms of this reaction pathway are discussed, identifying either a pathway based on hydrogen diffusion through Ni with water release at the TPB or a path with oxygen diffusion through Ni to be a very likely explanation for the experimental results.

  6. The TMI Regenerative Solid Oxide Fuel Cell

    Science.gov (United States)

    Cable, Thomas L.; Ruhl, Robert C.; Petrik, Michael

    1996-01-01

    Energy storage and production in space requires rugged, reliable hardware which minimizes weight, volume, and maintenance while maximizing power output and usable energy storage. Systems generally consist of photovoltaic solar arrays which operate (during sunlight cycles) to provide system power and regenerate fuel (hydrogen) via water electrolysis and (during dark cycles) fuel cells convert hydrogen into electricity. Common configurations use two separate systems (fuel cell and electrolyzer) in conjunction with photovoltaic cells. Reliability, power to weight and power to volume ratios could be greatly improved if both power production (fuel cells) and power storage (electrolysis) functions can be integrated into a single unit. The solid oxide fuel cell (SOFC) based design integrates fuel cell and electrolyzer functions and potentially simplifies system requirements. The integrated fuel cell/electrolyzer design also utilizes innovative gas storage concepts and operates like a rechargeable 'hydrogen-oxygen battery'. Preliminary research has been completed on improved H2/H20 electrode (SOFC anode/electrolyzer cathode) materials for regenerative fuel cells. Tests have shown improved cell performance in both fuel and electrolysis modes in reversible fuel cell tests. Regenerative fuel cell efficiencies, ratio of power out (fuel cell mode) to power in (electrolyzer mode), improved from 50 percent using conventional electrode materials to over 80 percent. The new materials will allow a single SOFC system to operate as both the electolyzer and fuel cell. Preliminary system designs have also been developed to show the technical feasibility of using the design for space applications requiring high energy storage efficiencies and high specific energy. Small space systems also have potential for dual-use, terrestrial applications.

  7. Towards Multi Fuel SOFC Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Clausen, Lasse Røngaard; Bang-Møller, Christian

    2011-01-01

    Complete Solid Oxide Fuel Cell (SOFC) plants fed by several different fuels are suggested and analyzed. The plants sizes are about 10 kW which is suitable for single family house with needs for both electricity and heat. Alternative fuels such as, methanol, DME (Di-Methyl Ether) and ethanol...... are also considered and the results will be compared with the base plant fed by Natural Gas (NG). A single plant design will be suggested that can be fed with methanol, DME and ethanol whenever these fuels are available. It will be shown that the plant fed by ethanol will have slightly higher electrical...

  8. Benchmarking the expected stack manufacturing cost of next generation, intermediate-temperature protonic ceramic fuel cells with solid oxide fuel cell technology

    Science.gov (United States)

    Dubois, Alexis; Ricote, Sandrine; Braun, Robert J.

    2017-11-01

    Recent progress in the performance of intermediate temperature (500-600 °C) protonic ceramic fuel cells (PCFCs) has demonstrated both fuel flexibility and increasing power density that approach commercial application requirements. These developments may eventually position the technology as a viable alternative to solid oxide fuel cells (SOFCs) and molten carbonate fuel cells (MCFCs). The PCFCs investigated in this work are based on a BaZr0.8Y0.2O3-δ (BZY20) thin electrolyte supported by BZY20/Ni porous anodes, and a triple conducting cathode material comprised of BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY0.1). These cells are prepared using a low-cost solid-state reactive sintering (SSRS) process, and are capable of power densities of 0.156 W cm-2 at 500 °C operating directly from methane fuel. We develop a manufacturing cost model to estimate the Nth generation production costs of PCFC stack technology using high volume manufacturing processes and compare them to the state-of-the-art in SOFC technology. The low-cost cell manufacturing enabled by the SSRS technique compensates for the lower PCFC power density and the trade-off between operating temperature and efficiency enables the use of lower-cost stainless steel materials. PCFC stack production cost estimates are found to be as much as 27-37% lower at 550 °C than SOFCs operating at 800 °C.

  9. Hydrogen generation from natural gas for the fuel cell systems of tomorrow

    Science.gov (United States)

    Dicks, Andrew L.

    In most cases hydrogen is the preferred fuel for use in the present generation of fuel cells being developed for commercial applications. Of all the potential sources of hydrogen, natural gas offers many advantages. It is widely available, clean, and can be converted to hydrogen relatively easily. When catalytic steam reforming is used to generate hydrogen from natural gas, it is essential that sulfur compounds in the natural gas are removed upstream of the reformer and various types of desulfurisation processes are available. In addition, the quality of fuel required for each type of fuel cell varies according to the anode material used, and the cell temperature. Low temperature cells will not tolerate high concentrations of carbon monoxide, whereas the molten fuel cell (MCFC) and solid oxide fuel cell (SOFC) anodes contain nickel on which it is possible to electrochemically oxidise carbon monoxide directly. The ability to internally reform fuel gas is a feature of the MCFC and SOFC. Internal reforming can give benefits in terms of increased electrical efficiency owing to the reduction in the required cell cooling and therefore parasitic system losses. Direct electrocatalysis of hydrocarbon oxidation has been the elusive goal of fuel cell developers over many years and recent laboratory results are encouraging. This paper reviews the principal methods of converting natural gas into hydrogen, namely catalytic steam reforming, autothermic reforming, pyrolysis and partial oxidation; it reviews currently available purification techniques and discusses some recent advances in internal reforming and the direct use of natural gas in fuel cells.

  10. Development of a Novel Efficient Solid-Oxide Hybrid for Co-generation of Hydrogen and Electricity Using Nearby Resources for Local Application

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Greg, G.; Virkar, Anil, V.; Bandopadhyay, Sukumar; Thangamani, Nithyanantham; Anderson, Harlan, U.; Brow, Richard, K.

    2009-06-30

    Developing safe, reliable, cost-effective, and efficient hydrogen-electricity co-generation systems is an important step in the quest for national energy security and minimized reliance on foreign oil. This project aimed to, through materials research, develop a cost-effective advanced technology cogenerating hydrogen and electricity directly from distributed natural gas and/or coal-derived fuels. This advanced technology was built upon a novel hybrid module composed of solid-oxide fuel-assisted electrolysis cells (SOFECs) and solid-oxide fuel cells (SOFCs), both of which were in planar, anode-supported designs. A SOFEC is an electrochemical device, in which an oxidizable fuel and steam are fed to the anode and cathode, respectively. Steam on the cathode is split into oxygen ions that are transported through an oxygen ion-conducting electrolyte (i.e. YSZ) to oxidize the anode fuel. The dissociated hydrogen and residual steam are exhausted from the SOFEC cathode and then separated by condensation of the steam to produce pure hydrogen. The rationale was that in such an approach fuel provides a chemical potential replacing the external power conventionally used to drive electrolysis cells (i.e. solid oxide electrolysis cells). A SOFC is similar to the SOFEC by replacing cathode steam with air for power generation. To fulfill the cogeneration objective, a hybrid module comprising reversible SOFEC stacks and SOFC stacks was designed that planar SOFECs and SOFCs were manifolded in such a way that the anodes of both the SOFCs and the SOFECs were fed the same fuel, (i.e. natural gas or coal-derived fuel). Hydrogen was produced by SOFECs and electricity was generated by SOFCs within the same hybrid system. A stand-alone 5 kW system comprising three SOFEC-SOFC hybrid modules and three dedicated SOFC stacks, balance-of-plant components (including a tailgas-fired steam generator and tailgas-fired process heaters), and electronic controls was designed, though an overall

  11. The effect of oxygen transfer mechanism on the cathode performance based on proton-conducting solid oxide fuel cells

    KAUST Repository

    Hou, Jie

    2015-01-01

    Two types of proton-blocking composites, La2NiO4+δ-LaNi0.6Fe0.4O3-δ (LNO-LNF) and Sm0.2Ce0.8O2-δ-LaNi0.6Fe0.4O3-δ (SDC-LNF), were evaluated as cathode materials for proton-conducting solid oxide fuel cells (H-SOFCs) based on the BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte, in order to compare and investigate the influence of two different oxygen transfer mechanism on the performance of the cathode for H-SOFCs. The X-ray diffraction (XRD) results showed that the chemical compatibility of the components in both compounds was excellent up to 1000°C. Electrochemical studies revealed that LNO-LNF showed lower area specific polarization resistances in symmetrical cells and better electrochemical performance in single cell tests. The single cell with LNO-LNF cathode generated remarkable higher maximum power densities (MPDs) and lower interfacial polarization resistances (Rp) than that with SDC-LNF cathode. Correspondingly, the MPDs of the single cell with the LNO-LNF cathode were 490, 364, 266, 180 mW cm-2 and the Rp were 0.103, 0.279, 0.587, 1.367 Ω cm2 at 700, 650, 600 and 550°C, respectively. Moreover, after the single cell with LNO-LNF cathode optimized with an anode functional layer (AFL) between the anode and electrolyte, the power outputs reached 708 mW cm-2 at 700°C. These results demonstrate that the LNO-LNF composite cathode with the interstitial oxygen transfer mechanism is a more preferable alternative for H-SOFCs than SDC-LNF composite cathode with the oxygen vacancy transfer mechanism.

  12. Integration of solid oxide fuel cell (SOFC) and chemical looping combustion (CLC) for ultra-high efficiency power generation and CO2 production

    NARCIS (Netherlands)

    Spallina, Vincenzo; Nocerino, Pasquale; Romano, Matteo C.; van Sint Annaland, Martin; Campanari, Stefano; Gallucci, Fausto

    2018-01-01

    This work presents a thermodynamic analysis of the integration of solid oxide fuel cells (SOFCs) with chemical looping combustion (CLC) in natural gas power plants. The fundamental idea of the proposed process integration is to use a dual fluidized-bed CLC process to complete the oxidation of the

  13. Reversibility of the SOFC for the hydrogen production by high temperature electrolysis; Reversibilite des SOFC pour la production d'hydrogene par electrolyse haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Brisse, A.; Marrony, M.; Perednis, D.; Schefold, J.; Jose-Garcia, M.; Zahid, M. [Institut Europeen de Recherche sur l' Energie (EIFER), Karlsruhe (Germany)

    2007-07-01

    The behaviour of two SOFC cells in electrolysis mode is studied. The performances of these solid oxide cells, reversible at 800 C and for current densities between 0 and -0.42 A/cm{sup 2}, are presented. A weaker polarisation resistance has been measured for the cell containing a mixed conductor as oxygen electrode. For each cell, a limitation by gaseous diffusion has been observed under current. This phenomenon appears for current densities which are higher for the mixed conductor cell as oxygen electrode. (O.M.)

  14. Preparation of Sr2(MgMo)1-xRuxO6 ceramics for use in a solid oxide fuel cell anode

    International Nuclear Information System (INIS)

    Bezerra, Matheus Eiji Ohno; Florio, Daniel Zanetti de; Fonseca, Fabio Coral

    2016-01-01

    Full text: Solid Oxide Fuel Cells are the most efficient devices known for the direct conversion of fuels into electric energy. Such devices have advanced steadily and are already available for specific applications such as portable power and residential stationary generation. The main objective of this work is the development of anodes for SOFC operating directly with renewable fuels, without the addition of water and using strategic fuels such as ethanol and natural gas. Specifically, a family of mixed ionic-electronic compounds has been investigated: the double perovskites with compositions Sr 2 (MgMo) 1-x Ru x O 6 with x = 0; 1; 2; 5; 10 e 20 at.%. This material has been synthesized by polymeric precursor method. The resins were prepared by combining stoichiometric amounts of the starting solutions. The resulting solution was heated treated under magnetic stirring. The thermal decomposition of the polymeric resin was studied by means of simultaneous thermogravimetric and differential scanning calorimetry up to 1500 °C with heating and cooling rates of 10 °/min in Ar. The thermal decomposition result shows mass loss up to, approximately, 900 °C. However X-ray diffraction analyses of the powder heat treated at 900 °C and 1200 °C presents a considerable content of an undesiderate phase (SrMoO 4 ). According to the literature for similar compounds a thermal treatment under reduction conditions could be necessary to obtain the double perovskites single phase. After this treatment the material will be characterized regarding its electrical properties. The expected results will contribute to advance both the understanding of the mixed ionic electronic ceramics and the SOFC technology using renewable fuels. (author)

  15. Fracture-mechanical analysis of metal/ceramic composites for applications in high-temperature fuel cells (SOFC); Bruchmechanische Untersuchung von Metall/Keramik-Verbunsystemen fuer die Anwendung in der Hochtemperaturbrennstoffzelle (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Bernd Josef

    2008-08-25

    The author investigated the deformation and damage behaviour of soldered ceramic/metal joints in SOFC stacks, using thermochemical methods. Methods for analyzing sandwich systems and for mechanical characterization of joints were adapted and modified in order to provide fundamental understanding of the mechanical properties of soldered joints. [German] In dieser Arbeit wurde das Verformungs- und Schaedigungsverhalten von Keramik/ Metall-Loetverbindungen fuer SOFC-Stacks thermomechanisch untersucht. Verfahren zur Analyse von Schichtsystemen und fuer die mechanische Charakterisierung von Fuegeverbindungen wurden adaptiert und weiterentwickelt, um zu einem grundlegenden Verstaendnis der mechanischen Eigenschaften von Loetverbindungen zu gelangen.

  16. Optimal fault-tolerant control strategy of a solid oxide fuel cell system

    Science.gov (United States)

    Wu, Xiaojuan; Gao, Danhui

    2017-10-01

    For solid oxide fuel cell (SOFC) development, load tracking, heat management, air excess ratio constraint, high efficiency, low cost and fault diagnosis are six key issues. However, no literature studies the control techniques combining optimization and fault diagnosis for the SOFC system. An optimal fault-tolerant control strategy is presented in this paper, which involves four parts: a fault diagnosis module, a switching module, two backup optimizers and a controller loop. The fault diagnosis part is presented to identify the SOFC current fault type, and the switching module is used to select the appropriate backup optimizer based on the diagnosis result. NSGA-II and TOPSIS are employed to design the two backup optimizers under normal and air compressor fault states. PID algorithm is proposed to design the control loop, which includes a power tracking controller, an anode inlet temperature controller, a cathode inlet temperature controller and an air excess ratio controller. The simulation results show the proposed optimal fault-tolerant control method can track the power, temperature and air excess ratio at the desired values, simultaneously achieving the maximum efficiency and the minimum unit cost in the case of SOFC normal and even in the air compressor fault.

  17. Power output of microbial fuel cell emphasizing interaction of anodic binder with bacteria

    Science.gov (United States)

    Li, Hongying; Liao, Bo; Xiong, Juan; Zhou, Xingwang; Zhi, Huozhen; Liu, Xiang; Li, Xiaoping; Li, Weishan

    2018-03-01

    Electrochemically active biofilm is necessary for the electron transfer between bacteria and anodic electrode in microbial fuel cells and selecting the type of anodic electrode material that favours formation of electrochemically active biofilm is crucial for the microbial fuel cell operation. We report a new finding that the interaction of anodic binder with bacteria plays more important role than its hydrophilicity for forming an electrochemically active biofilm, which is emphasized by applying poly(bisphenol A-co-epichorohydrin) as an anodic binder of the microbial fuel cell based on carbon nanotubes as anodic electrode and Escherichia coli as bacterium. The physical characterizations and electrochemical measurements demonstrate that poly(bisphenol A-co-epichorohydrin) exhibits a strong interaction with bacteria and thus provides the microbial fuel cell with excellent power density output. The MFC using poly(bisphenol A-co-epichorohydrin) reaches a maximum power density output of 3.8 W m-2. This value is larger than that of the MFCs using polytetrafluoroethylene that has poorer hydrophilicity, or polyvinyl alcohol that has better hydrophilicity but exhibits weaker interaction with bacteria than poly(bisphenol A-co-epichorohydrin).

  18. On the Properties and Long-Term Stability of Infiltrated Lanthanum Cobalt Nickelates (LCN) in Solid Oxide Fuel Cell Cathodes

    DEFF Research Database (Denmark)

    Kiebach, Wolff-Ragnar; Zielke, Philipp; Veltzé, Sune

    2017-01-01

    Infiltration as a fabrication method for solid oxide fuel cells (SOFC) electrodes is offering significant improvements in cell performance at reduced materials and fabrication costs, especially when combined with co-sintering. However, important questions regarding the long-term performance...... and microstructural stability remain unanswered. Here, we present the results of a three-year project, where large footprint anode-supported SOFCs with a co-sintered cathode backbone and infiltrated La0.95Co0.4Ni0.6O3 (LCN) cathodes were developed and thoroughly characterized. The initial long-term performance...... in the electrode properties using SEM, BET area, and in-plane conductivity measurements. Finally, the mechanical properties of co-sintered cathode backbone cells were determined in four-point bending tests carried out both at room temperature and at 800°C in air. Based on these results, degradation mechanisms were...

  19. Manufacturing Cost Analysis for YSZ-Based FlexCells at Pilot and Full Scale Production Scales

    Energy Technology Data Exchange (ETDEWEB)

    Scott Swartz; Lora Thrun; Robin Kimbrell; Kellie Chenault

    2011-05-01

    Significant reductions in cell costs must be achieved in order to realize the full commercial potential of megawatt-scale SOFC power systems. The FlexCell designed by NexTech Materials is a scalable SOFC technology that offers particular advantages over competitive technologies. In this updated topical report, NexTech analyzes its FlexCell design and fabrication process to establish manufacturing costs at both pilot scale (10 MW/year) and full-scale (250 MW/year) production levels and benchmarks this against estimated anode supported cell costs at the 250 MW scale. This analysis will show that even with conservative assumptions for yield, materials usage, and cell power density, a cost of $35 per kilowatt can be achieved at high volume. Through advancements in cell size and membrane thickness, NexTech has identified paths for achieving cell manufacturing costs as low as $27 per kilowatt for its FlexCell technology. Also in this report, NexTech analyzes the impact of raw material costs on cell cost, showing the significant increases that result if target raw material costs cannot be achieved at this volume.

  20. Tracking Oxygen Vacancies in Thin Film SOFC Cathodes

    Science.gov (United States)

    Leonard, Donovan; Kumar, Amit; Jesse, Stephen; Kalinin, Sergei; Shao-Horn, Yang; Crumlin, Ethan; Mutoro, Eva; Biegalski, Michael; Christen, Hans; Pennycook, Stephen; Borisevich, Albina

    2011-03-01

    Oxygen vacancies have been proposed to control the rate of the oxygen reduction reaction and ionic transport in complex oxides used as solid oxide fuel cell (SOFC) cathodes [1,2]. In this study oxygen vacancies were tracked, both dynamically and statically, with the combined use of scanned probe microscopy (SPM) and scanning transmission electron microscopy (STEM). Epitaxial films of La 0.8 Sr 0.2 Co O3 (L SC113) and L SC113 / LaSrCo O4 (L SC214) on a GDC/YSZ substrate were studied, where the latter showed increased electrocatalytic activity at moderate temperature. At atomic resolution, high angle annular dark field STEM micrographs revealed vacancy ordering in L SC113 as evidenced by lattice parameter modulation and EELS studies. The evolution of oxygen vacancy concentration and ordering with applied bias and the effects of bias cycling on the SOFC cathode performance will be discussed. Research is sponsored by the of Materials Sciences and Engineering Division, U.S. DOE.

  1. High power density cell using nanostructured Sr-doped SmCoO3 and Sm-doped CeO2 composite powder synthesized by spray pyrolysis

    Science.gov (United States)

    Shimada, Hiroyuki; Yamaguchi, Toshiaki; Suzuki, Toshio; Sumi, Hirofumi; Hamamoto, Koichi; Fujishiro, Yoshinobu

    2016-01-01

    High power density solid oxide electrochemical cells were developed using nanostructure-controlled composite powder consisting of Sr-doped SmCoO3 (SSC) and Sm-doped CeO2 (SDC) for electrode material. The SSC-SDC nano-composite powder, which was synthesized by spray pyrolysis, had a narrow particle size distribution (D10, D50, and D90 of 0.59, 0.71, and 0.94 μm, respectively), and individual particles were spherical, composing of nano-size SSC and SDC fragments (approximately 10-15 nm). The application of the powder to a cathode for an anode-supported solid oxide fuel cell (SOFC) realized extremely fine cathode microstructure and excellent cell performance. The anode-supported SOFC with the SSC-SDC cathode achieved maximum power density of 3.65, 2.44, 1.43, and 0.76 W cm-2 at 800, 750, 700, and 650 °C, respectively, using humidified H2 as fuel and air as oxidant. This result could be explained by the extended electrochemically active region in the cathode induced by controlling the structure of the starting powder at the nano-order level.

  2. Heat science and transport phenomena in fuel cells; Thermique et phenomenes de transport dans les piles a combustible

    Energy Technology Data Exchange (ETDEWEB)

    Liberatore, P.M.; Boillot, M. [Laboratoire des Sciences du Genie Chimique de Nancy, 54 - Vandoeuvre-les-Nancy (France); Bonnet, C.; Didieerjean, S.; Lapicque, F.; Deseure, J.; Lottin, O.; Maillet, D.; Oseen-Senda, J. [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee, 54 - Vandoeuvre Les Nancy (France); Alexandre, A. [Laboratoire d' Etudes Thermiques, ENSMA, 86 Poitiers (France); Topin, F.; Occelli, R.; Daurelle, J.V. [IUSTI / Polytech' Marseille, Institut universitaire des Systemes Thermiques Industriels Ecole, 13 - Marseille (France); Pauchet, J.; Feidt, M. [CEA Grenoble, Groupement pour la recherche sur les echangeurs thermiques (Greth), 38 (France); Voarino, C. [CEA Centre d' Etudes du Ripault, 37 - Tours (France); Morel, B.; Laurentin, J.; Bultel, Y.; Lefebvre-Joud, F. [CEA Grenoble, LEPMI, 38 (France); Auvity, B.; Lasbet, Y.; Castelain, C.; Peerohossaini, H. [Ecole Centrale de Nantes, Laboratoire de Thermocinetique de Nantes (LTN), 44 - Nantes (France)

    2005-07-01

    In this work are gathered the transparencies of the lectures presented at the conference 'heat science and transport phenomena in fuel cells'. The different lectures have dealt with 1)the gas distribution in the bipolar plates of a fuel cell: experimental studies and computerized simulations 2)two-phase heat distributors in the PEMFC 3)a numerical study of the flow properties of the backing layers on the transfers in a PEMFC 4)modelling of the heat and mass transfers in a PEMFC 5)two-phase cooling of the PEMFC with pentane 6)stationary thermodynamic model of the SOFC in the GECOPAC system 7)modelling of the internal reforming at the anode of the SOFC 8)towards a new thermal design of the PEMFC bipolar plates. (O.M.)

  3. Low cost fuel cell diffusion layer configured for optimized anode water management

    Science.gov (United States)

    Owejan, Jon P; Nicotera, Paul D; Mench, Matthew M; Evans, Robert E

    2013-08-27

    A fuel cell comprises a cathode gas diffusion layer, a cathode catalyst layer, an anode gas diffusion layer, an anode catalyst layer and an electrolyte. The diffusion resistance of the anode gas diffusion layer when operated with anode fuel is higher than the diffusion resistance of the cathode gas diffusion layer. The anode gas diffusion layer may comprise filler particles having in-plane platelet geometries and be made of lower cost materials and manufacturing processes than currently available commercial carbon fiber substrates. The diffusion resistance difference between the anode gas diffusion layer and the cathode gas diffusion layer may allow for passive water balance control.

  4. Investigation of Novel Electrocatalysts for Metal Supported Solid Oxide Fuel Cells - Ru:GDC

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Nielsen, Jimmi; Thydén, Karl Tor Sune

    2015-01-01

    Even though solid oxide fuel cells (SOFCs) have a high potential with respect to efficiency and fuel flexibility they are not yet competitive in terms of cost and durability with conventional chemical energy conversion technologies. The potential cost reduction can be achieved through...... in tolerating the vibrations, transient loads, thermal and redox cycling [1-2]. The DTU MS-SOFC design based on ferritic stainless steel requires incorporation of electrocatalyst into the anode functional layer by infiltration methods [3]. Previously, the preferred electrocatalyst has been gadolinium doped...... and microstructure of the infiltrated electrocatalyst layer was characterized using high-resolution electron microscopy. The electrochemical characterization involved polarization curves and electrochemical impedance spectroscopy (EIS) in the temperature range of 650-750ºC. The polarization curve for Ru...

  5. Analyses of Large Coal-Based SOFCs for High Power Stack Block Development

    Energy Technology Data Exchange (ETDEWEB)

    Recknagle, Kurtis P; Koeppel, Brian J

    2010-10-01

    This report summarizes the numerical modeling and analytical efforts for SOFC stack development performed for the coal-based SOFC program. The stack modeling activities began in 2004, but this report focuses on the most relevant results obtained since August 2008. This includes the latter half of Phase-I and all of Phase-II activities under technical guidance of VPS and FCE. The models developed to predict the thermal-flow-electrochemical behaviors and thermal-mechanical responses of generic planar stacks and towers are described. The effects of cell geometry, fuel gas composition, on-cell reforming, operating conditions, cell performance, seal leak, voltage degradation, boundary conditions, and stack height are studied. The modeling activities to evaluate and achieve technical targets for large stack blocks are described, and results from the latest thermal-fluid-electrochemical and structural models are summarized. Modeling results for stack modifications such as scale-up and component thickness reduction to realize cost reduction are presented. Supporting modeling activities in the areas of cell fabrication and loss of contact are also described.

  6. Modeling of the anode side of a direct methanol fuel cell with analytical solutions

    International Nuclear Information System (INIS)

    Mosquera, Martin A.; Lizcano-Valbuena, William H.

    2009-01-01

    In this work, analytical solutions were derived (for any methanol oxidation reaction order) for the profiles of methanol concentration and proton current density, by assuming diffusion mass transport mechanism, Tafel kinetics, and fast proton transport in the anodic catalyst layer of a direct methanol fuel cell. An expression for the Thiele modulus that allows to express the anodic overpotential as a function of the cell current and kinetic and mass transfer parameters was obtained. For high cell current densities, it was found that the Thiele modulus (φ 2 ) varies quadratically with cell current density; yielding a simple correlation between anodic overpotential and cell current density. Analytical solutions were derived for the profiles of both local methanol concentration in the catalyst layer and local anodic current density in the catalyst layer. Under the assumptions of the model presented here, in general, the local methanol concentration in the catalyst layer cannot be expressed as an explicit function of the position in the layer. In spite of this, the equations presented here for the anodic overpotential allow the derivation of new semi-empirical equations

  7. A cobalt-free perovskite-type La{sub 0.6}Sr{sub 0.4}Fe{sub 0.9}Cr{sub 0.1}O{sub 3-{alpha}} cathode for proton-conducting intermediate temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Zuolong; Yang, Zhijie; Zhao, Dongmei; Deng, Xuli [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Ma, Guilin, E-mail: 32uumagl@suda.edu.cn [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer A cobalt-free cathode material LSFC10 for IT-SOFCs was prepared and studied in detail. Black-Right-Pointing-Pointer The conductivity of LSFC10 reached 138 S cm{sup -1} under oxygen at 550 Degree-Sign C. Black-Right-Pointing-Pointer An anode-supported BZCY electrolyte membrane was successfully fabricated by a simple spin coating process. Black-Right-Pointing-Pointer Power density of the ceramic membrane fuel cell using LSFC10 as cathode reached 412 mW cm{sup -2} at 700 Degree-Sign C. - Abstract: A cobalt-free perovskite-type cathode material La{sub 0.6}Sr{sub 0.4}Fe{sub 0.9}Cr{sub 0.1}O{sub 3-{alpha}} (LSFC10) was prepared by a citric acid-nitrate process and investigated as a potential cathode material for proton-conducting intermediate-temperature solid oxide fuel cells (IT-SOFCs). The maximum conductivity of LSFC10 reached 138 S cm{sup -1} under oxygen at 550 Degree-Sign C. A Ni-BZCY composite anode-supported proton-conducting BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{alpha}} (BZCY) electrolyte membrane was successfully fabricated by a simple, cost-effective spin coating process. The peak power densities of the H{sub 2}/O{sub 2} fuel cell using BZCY electrolyte membrane, Ni-BZCY composite anode and LSFC10 cathode reached 412 mW cm{sup -2}, and the interfacial polarization resistance for the fuel cell was as low as 0.19 {Omega} cm{sup 2} under open circuit conditions, at 700 Degree-Sign C. These results reveal LSFC10 is a suitable cathode material for proton-conducting IT-SOFCs.

  8. Anodizing color coded anodized Ti6Al4V medical devices for increasing bone cell functions.

    Science.gov (United States)

    Ross, Alexandra P; Webster, Thomas J

    2013-01-01

    Current titanium-based implants are often anodized in sulfuric acid (H(2)SO(4)) for color coding purposes. However, a crucial parameter in selecting the material for an orthopedic implant is the degree to which it will integrate into the surrounding bone. Loosening at the bone-implant interface can cause catastrophic failure when motion occurs between the implant and the surrounding bone. Recently, a different anodization process using hydrofluoric acid has been shown to increase bone growth on commercially pure titanium and titanium alloys through the creation of nanotubes. The objective of this study was to compare, for the first time, the influence of anodizing a titanium alloy medical device in sulfuric acid for color coding purposes, as is done in the orthopedic implant industry, followed by anodizing the device in hydrofluoric acid to implement nanotubes. Specifically, Ti6Al4V model implant samples were anodized first with sulfuric acid to create color-coding features, and then with hydrofluoric acid to implement surface features to enhance osteoblast functions. The material surfaces were characterized by visual inspection, scanning electron microscopy, contact angle measurements, and energy dispersive spectroscopy. Human osteoblasts were seeded onto the samples for a series of time points and were measured for adhesion and proliferation. After 1 and 2 weeks, the levels of alkaline phosphatase activity and calcium deposition were measured to assess the long-term differentiation of osteoblasts into the calcium depositing cells. The results showed that anodizing in hydrofluoric acid after anodizing in sulfuric acid partially retains color coding and creates unique surface features to increase osteoblast adhesion, proliferation, alkaline phosphatase activity, and calcium deposition. In this manner, this study provides a viable method to anodize an already color coded, anodized titanium alloy to potentially increase bone growth for numerous implant applications.

  9. Coating for lithium anode, thionyl chloride active cathode electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Catanzarite, V.O.

    1983-01-04

    Electrochemical power cells having a cathode current collector, a combination liquid active cathode depolarizer electrolyte solvent and an anode that forms surface compounds when in intimate contact with the liquid cathode are enhanced by the addition of a passivation limiting film contiguous to said anode. The passivating film is a member of the cyanoacrilate family of organic compounds.

  10. Coating for lithium anode, thionyl chloride active cathode electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Catanzarite, V.O.

    1981-10-20

    Electrochemical power cells having a cathode current collector, a combination liquid active cathode depolarizer electrolyte solvent and an anode that forms surface compounds when in intimate contact with the liquid cathode are enhanced by the addition of a passivation limiting film contiguous to said anode. The passivating film is a member of the cyanoacrilate family of organic compounds.

  11. Internal reforming characteristics of cermet supported solid oxide fuel cell using yttria stabilized zirconia fed with partially reformed methane

    Energy Technology Data Exchange (ETDEWEB)

    Momma, Akihiko; Takano, Kiyonami; Tanaka, Yohei; Negishi, Akira; Kato, Ken; Nozaki, Ken; Kato, Tohru [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono Tsukuba Ibaraki, 305-8568 (Japan); Ichigi, Takenori; Matsuda, Kazuyuki; Ryu, Takashi [Application Development Project, Corporate R and D, NGK Insulators, Ltd., 2-56 Suda-cho Mizuho-ku Nagoya-shi Aichi, 467-8530 (Japan)

    2009-08-01

    In order to investigate the internal reforming characteristics in a cermet supported solid oxide fuel cell (SOFC) using YSZ as the electrolyte, the concentration profiles of the gaseous species along the gas flow direction in the anode were measured. Partially reformed methane using a pre-reformer kept at a constant temperature is supplied to the center of the cell which is operated with a seal-less structure at the gas outlet. The anode gas is sucked in via silica capillaries to the initially evacuated gas tanks. The process is simultaneously carried out using five sampling ports. The sampled gas is analyzed by a gas chromatograph. Most of the measurements are made at the cell temperature (T{sub cell}) of 750 C and at various temperatures of the pre-reformer (T{sub ref}) with various fuel utilizations (U{sub f}) of the cell. The composition of the fuel at the inlet of the anode was confirmed to be almost the same as that theoretically calculated assuming equilibrium at the temperature of the pre-reformer. The effect of internal reforming in the anode is clearly observed as a steady decrease in the methane concentration along the flow axis. The effect of the water-gas shift reaction is also observed as a decrease in the CO{sub 2} concentration and an increase of CO concentration around the gas inlet region, as the water-gas shift reaction inversely proceeds when T{sub cell} is higher than T{sub ref}. The diffusion of nitrogen from the seal-less outermost edge is observed, and the diffusion is confirmed to be more significant as U{sub f} decreases. The observations are compared with the results obtained by the SOFC supported by lanthanum gallate electrolyte. With respect to the internal reforming performance, the cell investigated here is found to be more effective when compared to the previously reported electrolyte supported cell. (author)

  12. Anodizing color coded anodized Ti6Al4V medical devices for increasing bone cell functions

    Directory of Open Access Journals (Sweden)

    Webster TJ

    2013-01-01

    Full Text Available Alexandra P Ross, Thomas J WebsterSchool of Engineering and Department of Orthopedics, Brown University, Providence, RI, USAAbstract: Current titanium-based implants are often anodized in sulfuric acid (H2SO4 for color coding purposes. However, a crucial parameter in selecting the material for an orthopedic implant is the degree to which it will integrate into the surrounding bone. Loosening at the bone–implant interface can cause catastrophic failure when motion occurs between the implant and the surrounding bone. Recently, a different anodization process using hydrofluoric acid has been shown to increase bone growth on commercially pure titanium and titanium alloys through the creation of nanotubes. The objective of this study was to compare, for the first time, the influence of anodizing a titanium alloy medical device in sulfuric acid for color coding purposes, as is done in the orthopedic implant industry, followed by anodizing the device in hydrofluoric acid to implement nanotubes. Specifically, Ti6Al4V model implant samples were anodized first with sulfuric acid to create color-coding features, and then with hydrofluoric acid to implement surface features to enhance osteoblast functions. The material surfaces were characterized by visual inspection, scanning electron microscopy, contact angle measurements, and energy dispersive spectroscopy. Human osteoblasts were seeded onto the samples for a series of time points and were measured for adhesion and proliferation. After 1 and 2 weeks, the levels of alkaline phosphatase activity and calcium deposition were measured to assess the long-term differentiation of osteoblasts into the calcium depositing cells. The results showed that anodizing in hydrofluoric acid after anodizing in sulfuric acid partially retains color coding and creates unique surface features to increase osteoblast adhesion, proliferation, alkaline phosphatase activity, and calcium deposition. In this manner, this study

  13. Analysis of Gas Leakage and Current Loss of Solid Oxide Fuel Cells by Screen Printing

    DEFF Research Database (Denmark)

    Jia, Chuan; Han, Minfang; Chen, Ming

    2017-01-01

    Two types of anode supported solid oxide fuel cell (SOFC) NiO-YSZ/YSZ/GDC/LSCF with the same structure and different manufacturing process were tested. Gas leakage was suspected for cells manufactured with screen printing technique. Effective leak current densities for both types of cells were...... calculated. Their performances of electrochemical impedance spectroscopy (EIS) were compared and distribution function of relaxation times (DRT) technique was also used to find the clue of gas leakage. Finally, thinning and penetrating holes were observed in electrolyte layer, which confirmed the occurrence...

  14. Graphene–sponges as high-performance low-cost anodes for microbial fuel cells

    KAUST Repository

    Xie, Xing; Yu, Guihua; Liu, Nian; Bao, Zhenan; Criddle, Craig S.; Cui, Yi

    2012-01-01

    A high-performance microbial fuel cell (MFC) anode was constructed from inexpensive materials. Key components were a graphene-sponge (G-S) composite and a stainless-steel (SS) current collector. Anode fabrication is simple, scalable

  15. Development of innovative metal-supported IT-SOFC technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    The results of tests on a solid oxide fuel cell developed by Ceres Power Ltd are reported. The fabrication and construction of the thick film ceramic fuel cell on porous stainless steel substrate is described. Tests were conducted under constant load and under recycling. In stack development, the cells were interconnected by laser-welding the steel substrates to the plates. Possible concepts for an IT-SOFC based on a small CHP system were evaluated by computer modelling. The performance levels of the cell at various temperatures, and the cost estimates, are given as evidence of suitability for development towards commercialisation. The study was conducted as part of a UK DTI programme on New and Renewable Energy Sources.

  16. Predicting the ultimate potential of natural gas SOFC power cycles with CO2 capture - Part B: Applications

    Science.gov (United States)

    Campanari, Stefano; Mastropasqua, Luca; Gazzani, Matteo; Chiesa, Paolo; Romano, Matteo C.

    2016-09-01

    An important advantage of solid oxide fuel cells (SOFC) as future systems for large scale power generation is the possibility of being efficiently integrated with processes for CO2 capture. Focusing on natural gas power generation, Part A of this work assessed the performances of advanced pressurised and atmospheric plant configurations (SOFC + GT and SOFC + ST, with fuel cell integration within a gas turbine or a steam turbine cycle) without CO2 separation. This Part B paper investigates such kind of power cycles when applied to CO2 capture, proposing two ultra-high efficiency plant configurations based on advanced intermediate-temperature SOFCs with internal reforming and low temperature CO2 separation process. The power plants are simulated at the 100 MW scale with a set of realistic assumptions about FC performances, main components and auxiliaries, and show the capability of exceeding 70% LHV efficiency with high CO2 capture (above 80%) and a low specific primary energy consumption for the CO2 avoided (1.1-2.4 MJ kg-1). Detailed results are presented in terms of energy and material balances, and a sensitivity analysis of plant performance is developed vs. FC voltage and fuel utilisation to investigate possible long-term improvements. Options for further improvement of the CO2 capture efficiency are also addressed.

  17. Copper anode corrosion affects power generation in microbial fuel cells

    KAUST Repository

    Zhu, Xiuping

    2013-07-16

    Non-corrosive, carbon-based materials are usually used as anodes in microbial fuel cells (MFCs). In some cases, however, metals have been used that can corrode (e.g. copper) or that are corrosion resistant (e.g. stainless steel, SS). Corrosion could increase current through galvanic (abiotic) current production or by increasing exposed surface area, or decrease current due to generation of toxic products from corrosion. In order to directly examine the effects of using corrodible metal anodes, MFCs with Cu were compared with reactors using SS and carbon cloth anodes. MFCs with Cu anodes initially showed high current generation similar to abiotic controls, but subsequently they produced little power (2 mW m-2). Higher power was produced with microbes using SS (12 mW m-2) or carbon cloth (880 mW m-2) anodes, with no power generated by abiotic controls. These results demonstrate that copper is an unsuitable anode material, due to corrosion and likely copper toxicity to microorganisms. © 2013 Society of Chemical Industry.

  18. Copper anode corrosion affects power generation in microbial fuel cells

    KAUST Repository

    Zhu, Xiuping; Logan, Bruce E.

    2013-01-01

    Non-corrosive, carbon-based materials are usually used as anodes in microbial fuel cells (MFCs). In some cases, however, metals have been used that can corrode (e.g. copper) or that are corrosion resistant (e.g. stainless steel, SS). Corrosion could increase current through galvanic (abiotic) current production or by increasing exposed surface area, or decrease current due to generation of toxic products from corrosion. In order to directly examine the effects of using corrodible metal anodes, MFCs with Cu were compared with reactors using SS and carbon cloth anodes. MFCs with Cu anodes initially showed high current generation similar to abiotic controls, but subsequently they produced little power (2 mW m-2). Higher power was produced with microbes using SS (12 mW m-2) or carbon cloth (880 mW m-2) anodes, with no power generated by abiotic controls. These results demonstrate that copper is an unsuitable anode material, due to corrosion and likely copper toxicity to microorganisms. © 2013 Society of Chemical Industry.

  19. Effect of Slotted Anode on Gas Bubble Behaviors in Aluminum Reduction Cell

    Science.gov (United States)

    Sun, Meijia; Li, Baokuan; Li, Linmin; Wang, Qiang; Peng, Jianping; Wang, Yaowu; Cheung, Sherman C. P.

    2017-12-01

    In the aluminum reduction cells, gas bubbles are generated at the bottom of the anode which eventually reduces the effective current contact area and the system efficiency. To encourage the removal of gas bubbles, slotted anode has been proposed and increasingly adopted by some industrial aluminum reduction cells. Nonetheless, the exact gas bubble removal mechanisms are yet to be fully understood. A three-dimensional (3D) transient, multiphase flow mathematical model coupled with magnetohydrodynamics has been developed to investigate the effect of slotted anode on the gas bubble movement. The Eulerian volume of fluid approach is applied to track the electrolyte (bath)-molten aluminum (metal) interface. Meanwhile, the Lagrangian discrete particle model is employed to handle the dynamics of gas bubbles with considerations of the buoyancy force, drag force, virtual mass force, and pressure gradient force. The gas bubble coalescence process is also taken into account based on the O'Rourke's algorithm. The two-way coupling between discrete bubbles and fluids is achieved by the inter-phase momentum exchange. Numerical predictions are validated against the anode current variation in an industrial test. Comparing the results using slotted anode with the traditional one, the time-averaged gas bubble removal rate increases from 36 to 63 pct; confirming that the slotted anode provides more escaping ways and shortens the trajectories for gas bubbles. Furthermore, the slotted anode also reduces gas bubble's residence time and the probability of coalescence. Moreover, the bubble layer thickness in aluminum cell with slotted anode is reduced about 3.5 mm (17.4 pct), so the resistance can be cut down for the sake of energy saving and the metal surface fluctuation amplitude is significantly reduced for the stable operation due to the slighter perturbation with smaller bubbles.

  20. Experimental investigation of solid oxide fuel cells using biomass gasification producer gases

    Energy Technology Data Exchange (ETDEWEB)

    Norheim, Arnstein

    2005-07-01

    performed here, the SOFC performance at varying inlet fuel gas composition was studied. In particular, variations in the fractions of hydrogen and carbon monoxide were studied. Switching from a hydrogen rich to a carbon monoxide rich fuel gas causes a significant reduction in the cell performance. However, even at 90% CO, the SOFC is able to produce power thus showing high fuel flexibility. It was further found that the SOFC performance was essentially the same when switching from a fuel gas composition similar to reformed natural gas to a gas composition similar to biomass gasification producer gases. These fuel gases were, however, mixed from gas bottles and therefore contained none of the trace species that may be present in gasifier producer gases. The second experimental series aimed at investigating the SOFC performance degradation as sulphur (H2S) was added to the fuel gas. At an operating temperature of 800 deg C the sulphur concentrations added were in the range from 5 to 240 ppm. During the first 400 hours of operation, the reference cell performance increased, i.e. the cell resistance at 0 ppm H2S decreased steadily making it difficult to quantify the effect of sulphur exactly. However, during the period when the cell was exposed to the highest sulphur concentrations the reference cell performance was constant and clearer conclusions could be drawn. It was found that the performance reduction was equal when the sulphur concentration in the fuel gas was 80, 120 and 240 ppm H2S. The results leads to the conclusion that the anode structure is saturated with sulphur at a relatively low sulphur concentration, probably in the vicinity of 10-20 ppm H2S. Further increasing the sulphur concentration in the fuel gas thus only causes marginal additional performance degradation. Post-experimental analysis of the cell structure gave no evidence of sulphur reacting chemically with the anode material. By repeating two of the experiments at 850 deg C no clear temperature