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Stephen J. Skinner - One of the best experts on this subject based on the ideXlab platform.

  • Intermediate Temperature solid oxide fuel cells
    Chemical Society Reviews, 2008
    Co-Authors: Dan J L Brett, A Atkinson, N P Brandon, Stephen J. Skinner
    Abstract:

    High Temperature solid oxide fuel cells (SOFCs), typified by developers such as Siemens Westinghouse and Rolls-Royce, operate in the Temperature region of 850–1000 °C. For such systems, very high efficiencies can be achieved from integration with gas turbines for large-scale stationary applications. However, high Temperature operation means that the components of the stack need to be predominantly ceramic and high Temperature metal alloys are needed for many balance-of-plant components. For smaller scale applications, where integration with a heat engine is not appropriate, there is a trend to move to lower Temperatures of operation, into the so-called Intermediate Temperature (IT) range of 500–750 °C. This expands the choice of materials and stack geometries that can be used, offering reduced system cost and, in principle, reducing the corrosion rate of stack and system components.This review introduces the IT-SOFC and explains the advantages of operation in this Temperature regime. The main advances made in materials chemistry that have made IT operation possible are described and some of the engineering issues and the new opportunities that reduced Temperature operation affords are discussed.This tutorial review examines the advances being made in materials and engineering that are allowing solid oxide fuel cells to operate at lower Temperature. The challenges and advantages of operating in the so-called ‘Intermediate Temperature’ range of 500–750 °C are discussed and the opportunities for applications not traditionally associated with solid oxide fuel cells are highlighted. This article serves as an introduction for scientists and engineers interested in Intermediate Temperature solid oxide fuel cells and the challenges and opportunities of reduced Temperature operation.

  • Intermediate Temperature solid oxide fuel cells.
    Chem Soc Rev, 2008
    Co-Authors: Stephen J. Skinner
    Abstract:

    High Temperature solid oxide fuel cells (SOFCs), typified by developers such as Siemens Westinghouse and Rolls-Royce, operate in the Temperature region of 850-1000 degrees C. For such systems, very high efficiencies can be achieved from integration with gas turbines for large-scale stationary applications. However, high Temperature operation means that the components of the stack need to be predominantly ceramic and high Temperature metal alloys are needed for many balance-of-plant components. For smaller scale applications, where integration with a heat engine is not appropriate, there is a trend to move to lower Temperatures of operation, into the so-called Intermediate Temperature (IT) range of 500-750 degrees C. This expands the choice of materials and stack geometries that can be used, offering reduced system cost and, in principle, reducing the corrosion rate of stack and system components. This review introduces the IT-SOFC and explains the advantages of operation in this Temperature regime. The main advances made in materials chemistry that have made IT operation possible are described and some of the engineering issues and the new opportunities that reduced Temperature operation affords are discussed. This tutorial review examines the advances being made in materials and engineering that are allowing solid oxide fuel cells to operate at lower Temperature. The challenges and advantages of operating in the so-called 'Intermediate Temperature' range of 500-750 degrees C are discussed and the opportunities for applications not traditionally associated with solid oxide fuel cells are highlighted. This article serves as an introduction for scientists and engineers interested in Intermediate Temperature solid oxide fuel cells and the challenges and opportunities of reduced Temperature operation.

  • gdbaco2o5 x layered perovskite as an Intermediate Temperature solid oxide fuel cell cathode
    Journal of Power Sources, 2007
    Co-Authors: A Tarancon, Stephen J. Skinner, J A Kilner, F Hernandezramirez, Alejandro Morata, G Dezanneau, Sonia Estrade, F Peiro, J R Morante
    Abstract:

    Abstract GdBaCo 2 O 5+ x (GBCO) was evaluated as a cathode for Intermediate-Temperature solid oxide fuel cells. A porous layer of GBCO was deposited on an anode-supported fuel cell consisting of a 15 μm thick electrolyte of yttria-stabilized zirconia (YSZ) prepared by dense screen-printing and a Ni–YSZ cermet as an anode (Ni–YSZ/YSZ/GBCO). Values of power density of 150 mW cm −2 at 700 °C and ca. 250 mW cm −2 at 800 °C are reported for this standard configuration using 5% of H 2 in nitrogen as fuel. An Intermediate porous layer of YSZ was introduced between the electrolyte and the cathode improving the performance of the cell. Values for power density of 300 mW cm −2 at 700 °C and ca. 500 mW cm −2 at 800 °C in this configuration were achieved.

  • layered perovskites as promising cathodes for Intermediate Temperature solid oxide fuel cells
    Journal of Materials Chemistry, 2007
    Co-Authors: A Tarancon, Stephen J. Skinner, R J Chater, F Hernandezramirez, J A Kilner
    Abstract:

    The suitability of GdBaCo2O5+δ as a cathode material for Intermediate Temperature solid oxide fuel cells has been evaluated. The 18O/16O isotope exchange depth profile (IEDP) method has been used to obtain the oxygen surface exchange and oxygen tracer diffusion coefficients yielding optimum values for applicability in fuel cells (k* = 2.8 × 10−7 cm s−1 and D* = 4.8 × 10−10 cm2 s−1 at 575 °C) especially in terms of low activation energies (EAk = 0.81(4) and EAD = 0.60(4) eV). The same material has been characterized electrically as a part of a symmetrical electrochemical system (GdBaCo2O5+δ/Ce0.9Gd0.1O2−x/GdBaCo2O5+δ), by means of impedance spectroscopy measurements, corroborating an excellent performance in the classical Intermediate Temperature range for solid oxide fuel cells (500–700 °C). An area specific resistance (electrode–electrolyte interface) of 0.25 Ω cm2 at 625 °C was achieved for a cell processing Temperature of 975 °C. Finally, layered perovskites are presented as a promising new family of materials for cathode use in solid oxide fuel cells at low Temperatures.

J A Kilner - One of the best experts on this subject based on the ideXlab platform.

  • materials for Intermediate Temperature solid oxide fuel cells
    Annual Review of Materials Research, 2014
    Co-Authors: J A Kilner, Monica Burriel
    Abstract:

    Solid-oxide fuel cells are devices for the efficient conversion of chemical energy to electrical energy and heat. Research efforts are currently addressed toward the optimization of cells operating at Temperatures in the region of 600°C, known as Intermediate-Temperature solid-oxide fuel cells, for which materials requirements are very stringent. In addition to the requirements of mechanical and chemical compatibility, the materials must show a high degree of oxide ion mobility and electrochemical activity at this low Temperature. Here we mainly examine the criteria for the development of two key components of Intermediate-Temperature solid-oxide fuel cells: the electrolyte and the cathode. We limit the discussion to novel approaches to materials optimization and focus on the fluorite oxide for electrolytes, principally those based on ceria and zirconia, and on perovskites and perovskite-related families in the case of cathodes.

  • gdbaco2o5 x layered perovskite as an Intermediate Temperature solid oxide fuel cell cathode
    Journal of Power Sources, 2007
    Co-Authors: A Tarancon, Stephen J. Skinner, J A Kilner, F Hernandezramirez, Alejandro Morata, G Dezanneau, Sonia Estrade, F Peiro, J R Morante
    Abstract:

    Abstract GdBaCo 2 O 5+ x (GBCO) was evaluated as a cathode for Intermediate-Temperature solid oxide fuel cells. A porous layer of GBCO was deposited on an anode-supported fuel cell consisting of a 15 μm thick electrolyte of yttria-stabilized zirconia (YSZ) prepared by dense screen-printing and a Ni–YSZ cermet as an anode (Ni–YSZ/YSZ/GBCO). Values of power density of 150 mW cm −2 at 700 °C and ca. 250 mW cm −2 at 800 °C are reported for this standard configuration using 5% of H 2 in nitrogen as fuel. An Intermediate porous layer of YSZ was introduced between the electrolyte and the cathode improving the performance of the cell. Values for power density of 300 mW cm −2 at 700 °C and ca. 500 mW cm −2 at 800 °C in this configuration were achieved.

  • layered perovskites as promising cathodes for Intermediate Temperature solid oxide fuel cells
    Journal of Materials Chemistry, 2007
    Co-Authors: A Tarancon, Stephen J. Skinner, R J Chater, F Hernandezramirez, J A Kilner
    Abstract:

    The suitability of GdBaCo2O5+δ as a cathode material for Intermediate Temperature solid oxide fuel cells has been evaluated. The 18O/16O isotope exchange depth profile (IEDP) method has been used to obtain the oxygen surface exchange and oxygen tracer diffusion coefficients yielding optimum values for applicability in fuel cells (k* = 2.8 × 10−7 cm s−1 and D* = 4.8 × 10−10 cm2 s−1 at 575 °C) especially in terms of low activation energies (EAk = 0.81(4) and EAD = 0.60(4) eV). The same material has been characterized electrically as a part of a symmetrical electrochemical system (GdBaCo2O5+δ/Ce0.9Gd0.1O2−x/GdBaCo2O5+δ), by means of impedance spectroscopy measurements, corroborating an excellent performance in the classical Intermediate Temperature range for solid oxide fuel cells (500–700 °C). An area specific resistance (electrode–electrolyte interface) of 0.25 Ω cm2 at 625 °C was achieved for a cell processing Temperature of 975 °C. Finally, layered perovskites are presented as a promising new family of materials for cathode use in solid oxide fuel cells at low Temperatures.

Fanglin Chen - One of the best experts on this subject based on the ideXlab platform.

  • La0.4Bi0.4Sr0.2FeO3-δ as Cobalt-free Cathode for Intermediate-Temperature Solid Oxide Fuel Cell
    Electrochimica Acta, 2016
    Co-Authors: Mei Li, Yuyu Ren, Zhesheng Zhu, Shiyue Zhu, Fanglin Chen, Yunsheng Zhang, Changrong Xia
    Abstract:

    La0.4Bi0.4Sr0.2FeO3-δ (LBSF) has previously been demonstrated to show the highest electrochemical performance in a series of bismuth doped lanthanum strontium ferrite La0.8-xBixSr0.2FeO3-δ where 0 ≤ x ≤ 0.8 as the cathode for Intermediate-Temperature solid oxide fuel cells. The cobalt-free electrocatalyst LBSF is further investigated in the present study using thermogravimetric analysis, oxygen Temperature-programmed desorption method, iodometric titration and high-Temperature X-ray diffraction refinement methods to reveal its structural properties including oxygen non-stoichiometry coefficient (δ), valence state of Fe, and lattice parameters at the different Temperatures. In addition, the oxygen reduction process on the single phase LBSF is explored using the distribution of relaxation time method based on the electrochemical impedance spectroscopy measurements conducted in oxygen partial pressure from 0.01 to 1.0 atm. The LBSF cathode electrochemical performance is effectively improved by cooperating Sm0.2Ce0.8O1.9 (SDC), an oxygen ion conductor, resulting in interfacial polarization resistance less than 0.1 Ω cm2 at 700°C when SDC is used as the electrolyte.

  • ba0 9co0 7fe0 2nb0 1o3 δ as cathode material for Intermediate Temperature solid oxide fuel cells
    Electrochemistry Communications, 2011
    Co-Authors: Chenghao Yang, Zhibin Yang, Fanglin Chen
    Abstract:

    Abstract Ba 0.9 Co 0.7 Fe 0.2 Nb 0.1 O 3 − δ (BCFN) perovskite material was synthesized and evaluated as cathode for La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 O 3 − δ (LSGM) electrolyte supported Intermediate Temperature solid oxide fuel cells (IT-SOFCs). X-ray diffraction results showed that BCFN was chemically compatible with the LSGM electrolyte. Maximum power densities of 0.36, 0.57, 0.80 and 1.1 W/cm 2 were obtained for LSGM electrolyte supported cells with BCFN as cathode and Ni-GDC as anode operated at 650, 700, 750 and 800 °C, respectively. Further, the cell performance was stable under a constant current of 0.6 A/cm 2 for over 204 h at 750 °C.

  • Doping effects on complex perovskite Ba3Ca1.18Nb1.82O9−δ Intermediate Temperature proton conductor
    Journal of Power Sources, 2011
    Co-Authors: Siwei Wang, Kyle Brinkman, Fei Zhao, Lingling Zhang, Fanglin Chen
    Abstract:

    In this work, the effects of Ce doping on the Ca and Nb ions in complex perovskite Ba3Ca1.18Nb1.82O9−δ (BCN18) proton conductor have been evaluated. It has been found that cerium ions can be doped into both the Ca and Nb sites to form a single-phase complex perovskite structure when the sintering Temperature is 1550 °C. Ce ions substituted with Nb ions enhances the electrical conductivity, especially the grain boundary conductivity. The highest conductivity has been obtained for a composition of Ba3Ca1.18Nb1.62Ce0.2O9−δ, possessing a conductivity of 2.69 × 10−3 S cm−1 at 550 °C in wet H2, a 78% enhancement compared with BCN18 (1.51 × 10−3 S cm−1). The chemical stability tests show that Ce-doped BCN18 samples remain single phase after treated either in boiling water for 7 h or in pure CO2 for 4 h at 700 °C. This work has demonstrated a new direction in developing Intermediate Temperature proton conducting materials that possess both high conductivity and good stability.

Zhenguo Yang - One of the best experts on this subject based on the ideXlab platform.

  • advanced Intermediate Temperature na s battery
    Energy and Environmental Science, 2013
    Co-Authors: Xiaochuan Lu, Vincent L Sprenkle, Guosheng Li, Brent W Kirby, Wu Xu, Jin Yong Kim, John P Lemmon, Zhenguo Yang
    Abstract:

    In this study, we reported an Intermediate-Temperature (∼150 °C) sodium–sulfur (Na–S) battery. With a relatively low operating Temperature, this novel battery could reduce the cost and safety issues associated with the conventional high-Temperature (300–350 °C) Na–S battery. A dense β′′-Al2O3 solid membrane and tetraglyme were utilized as the electrolyte separator and catholyte solvent in this battery. Solubility tests indicated that a cathode mixture of Na2S4 and S exhibited extremely high solubility in tetraglyme (e.g., >4.1 M for Na2S4 + 4 S). CV scans of Na2S4 in tetraglyme revealed two pairs of redox couples with peaks at around 2.22 and 1.75 V, corresponding to the redox reactions of polysulfide species. The discharge/charge profiles of the Na–S battery showed a slope region and a plateau, indicating multiple steps and cell reactions. In situ Raman measurements during battery operation suggested that polysulfide species were formed in the sequence of Na2S5 + S → Na2S5 + Na2S4 → Na2S4 + Na2S2 during discharge and in a reverse order during charge. This battery showed dramatic improvement in rate capacity and cycling stability over room-Temperature Na–S batteries, which makes it more attractive for renewable energy integration and other grid related applications.

  • chemical stability of glass seal interfaces in Intermediate Temperature solid oxide fuel cells
    Journal of Materials Engineering and Performance, 2004
    Co-Authors: Zhenguo Yang, Kerry D Meinhardt, Scott K Weil, Jeff W Stevenson
    Abstract:

    In Intermediate Temperature planar solid oxide fuel cell (SOFC) stacks, the interconnect, which is typically made from cost-effective, oxidation-resistant, high-Temperature alloys, is typically sealed to the ceramic positive electrode-electrolyte-negative electrode (PEN) by a sealing glass. To maintain the structural stability and minimize the degradation of stack performance, the sealing glass has to be chemically compatible with the PEN and alloy interconnects. In the present study, the chemical compatibility of a barium-calcium-aluminosilicate (BCAS) based glass-ceramic (specifically developed as a sealant in SOFC stacks) with a number of selected oxidation resistant high Temperature alloys (and the yttria-stabilized zirconia electrolyte) was evaluated. This paper reports the results of that study, with a particular focus on Crofer22 APU, a new ferritic stainless steel that was developed specifically for SOFC interconnect applications.

Andrzej Wieckowski - One of the best experts on this subject based on the ideXlab platform.

  • Accelerated CO electrooxidation through a formate pathway in Intermediate-Temperature alkaline media
    Electrochemistry Communications, 2012
    Co-Authors: Junhua Jiang, Andrzej Wieckowski
    Abstract:

    To explore strategies for addressing the process of CO poisoning on Pt-based catalysts, CO electrooxidation on Pt-based electrodes in alkaline media has been studied by cyclic voltammetry in the Intermediate Temperature range of 80 to 130 °C. In this Temperature range, CO spontaneously reacts with bulk hydroxide anion to generate soluble formate, which electrooxidation is apparently more facile than the CO electrooxidation. A pathway involving the formate Intermediate therefore results in accelerated CO electrooxidation. The corresponding voltammetric behaviors are characteristic of: (i) low onset potentials falling within the hydrogen zone, (ii) maximized oxidation currents in the double-layer zone and (iii) the oxidation inhibition in the oxide zone. These observations are quite different from the literature results for the CO electrooxidation in low Temperature alkaline media. This fact provides fundamentals for the development of novel fuel cell and hydrogen purification technologies since CO can be oxidized at very low potentials in the Intermediate Temperature alkaline media. © 2012 Elsevier B.V. All rights reserved.