Long-term and Redox Stability of Electrolyte Supported Solid Oxide Fuel Cells Under Various Operating Conditions

Mosch, Sindy; Trofimenko, Nikolai; Kusnezoff, M.; Betz, Thomas; Kellner, Marco

doi:10.1149/1.2729114

Cited by 10 publications

(7 citation statements)

References 13 publications

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“…For the blank sample we have measured power densities at 850 C of 418 and 459 mWcm À2 at 0.7 and 0.55 V respectively. Those values are comparable with similar YSZ supported cells, 20,21 although slightly lower due to the use of non-optimized electrodes in our case. For the machined sample, power densities at the same temperature were slightly improved up to 431 and 485 mWcm À2 at 0.7 and 0.55 V respectively.…”

Section: Physical Characterization Of the Electrolyte-to Verify If La...supporting

confidence: 90%

Self-Supporting Thin Yttria-Stabilised Zirconia Electrolytes for Solid Oxide Fuel Cells Prepared by Laser Machining

Larrea

Sola

Laguna‐Bercero

et al. 2011

J. Electrochem. Soc.

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A novel procedure to make self-supporting thin yttria-stabilised zirconia (YSZ) membranes by laser machining is shown. We have used a galvanometric controlled laser beam to machine the surface of a conventional sintered YSZ plate and achieved thin areas up to 10 lm thick, but also maintaining thicker support beams to ensure the structural strength of the membrane. The outer areas of the plate are left unaltered to facilitate the sealing of the cell. This kind of thin membrane is ideal for preparing electrolytesupported Solid Oxide Fuel Cells (SOFC) operating at intermediate temperatures. The membranes have been characterized by optical profilometry, Raman Spectroscopy and Electrochemical Impedance Spectroscopy. The YSZ properties, except those derived from membrane thinning, remain unaltered by processing. Using the laser machined YSZ electrolyte a conventional electrolyte supported YSZ-Ni/YSZ/LSM-YSZ planar single cell with average electrolyte thickness of less than 50 lm has been fabricated and characterized. Performance of the cell is improved as a result of the thinning process.The Solid Oxide Fuel Cell (SOFC) is one of the key devices for the transformation from the present fossil fuel based economy to a clean economy with zero emission energy use. The core of the SOFC is a solid electrolyte, an ionic conductor at high temperatures. At present, yttria-stabilised zirconia (YSZ) is still the most used electrolyte because of its unrivalled mechanical properties, chemical stability and high degree of knowledge achieved in this material. 1 As a first approach, the solid electrolyte behavior determines the cell performance and operation temperature. In this way, the Area Specific Resistance (ASR) of the electrolyte, defined as the ratio between the voltage drop in the electrolyte and the current density, is one of the main parameters of a SOFC. It is usually considered that this value has to be lower than $0.15 XÁcm 2 to get a cell with good performances. 2 The resistance of a conductor follows the relationshipThe conductivity being r, l the thickness and S the surface of the material. The conductivity of YSZ is a function of the temperature according to an Arrhenius type lawwhere T is the temperature, A the pre-exponential factor, E a the activation energy and k the Boltzmann constant. Since YSZ is a relatively poor electric conductor with E a % 1.1 eV and r (1000 C)3) the direct way to obtain low cell resistance is to prepare the electrolyte as a thin film and/or to operate the cell at high temperatures to get high enough ionic conductivity. Thin electrolytes can be deposited using different techniques such as tape casting, dip coating, spray-painting, etc. over one of the electrodes (either the cathode or the anode) that operate as structural support for the cell. The main advantage of this electrode-supported cell configuration is that very thin electrolytes can be used (usually 10-30 lm) and thus low resistance values are obtained for the most common electrolytes at intermediate temperatures (typically 750-85...

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Section: Physical Characterization Of the Electrolyte-to Verify If La...supporting

confidence: 90%

Self-Supporting Thin Yttria-Stabilised Zirconia Electrolytes for Solid Oxide Fuel Cells Prepared by Laser Machining

Larrea

Sola

Laguna‐Bercero

et al. 2011

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…For the blank sample we have measured power densities at 850ºC of 418 and 459 mWcm -2 at 0.7 and 0.55V respectively. Those values are comparable with similar YSZ supported cells (19,20), although slightly lower due to the use of non-optimized electrodes in our case. For the machined sample, power densities at the same temperature were improved up to 422 and 496 mWcm -2 at 0.7 and 0.55V respectively.…”

Section: Cell Prepared Using Machined Electrolytessupporting

confidence: 90%

Self-Supported Thin Yttria-Stabilized Zirconia Electrolytes for Solid Oxide Fuel Cells Prepared by Laser Machining

Larrea

Sola²,

Laguna‐Bercero³

et al. 2011

ECS Trans.

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A new procedure to fabricate self-supported thin yttria-stabilised zirconia membranes by laser machining is presented. We have used a galvanometric controlled laser beam to machine the surface of a conventional sintered YSZ plate and achieved thin areas up to 10 µm thick, but also maintaining thicker support beams to ensure the structural strength of the membrane. The outer areas of the plate are left unaltered to facilitate the sealing of the cell. This kind of thin membrane is ideal to prepare electrolyte-supported Solid Oxide Fuel Cells (SOFC) operating at low temperature. The membranes have been characterized by optical profilometry, Raman Spectroscopy and Electrochemical Impedance Spectroscopy. Using the laser machined YSZ electrolyte a conventional YSZ-Ni/YSZ/LSM planar Solid Oxide Fuel Cell has been fabricated and characterized.

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“…The cathode pastes based on the uLSM/ScSZ composite were fabricated by a method which is described elsewhere in detail (1,2). The pastes based on the NiO-YSZ cermet powder were prepared by mixing with organic binder, organic solvent and surface active additives.…”

Section: Methodsmentioning

confidence: 99%

“…The agglomeration rate can be reduced to acceptable level by using ZrO 2 /NiO composites. It has been demonstrated that the long-term degradation at high current densities can be reliably solved for electrolyte supported cells operating at 850°C (1) and mainly the degradation by redox cycling is the issue which should be addressed. The goal of the carried work was to optimize the electrode (microstructure) to sustain the longterm stability test at high current densities and the thermal and redox cycling.…”

Section: Introductionmentioning

confidence: 99%

Long-term, Redox and Thermal Cycling Stability of Electrolyte Supported Cells

Glauche¹,

Betz²,

Mosch³

et al. 2009

ECS Trans.

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The electrolyte supported cells with low area specific resistance (ASR<0.34 Ohm cm²) have been tested for long-term, thermal and redox stability in ceramic housing. It has been shown that the cells with optimized anode microstructure have degradation <0,1 % / 1000h and no measurable resistance change in the range of mistake of used method after ten thermal and redox cycles. The small fluctuation of contact resistance between anode and current collector has been observed especially during cycling experiments. The redox cycles lead to the largest fluctuation of ASR values during cycling due to direct influence on the bonds between anode and current collector.

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Long-term and Redox Stability of Electrolyte Supported Solid Oxide Fuel Cells Under Various Operating Conditions

Cited by 10 publications

References 13 publications

Self-Supporting Thin Yttria-Stabilised Zirconia Electrolytes for Solid Oxide Fuel Cells Prepared by Laser Machining

Self-Supporting Thin Yttria-Stabilised Zirconia Electrolytes for Solid Oxide Fuel Cells Prepared by Laser Machining

Self-Supported Thin Yttria-Stabilized Zirconia Electrolytes for Solid Oxide Fuel Cells Prepared by Laser Machining

Long-term, Redox and Thermal Cycling Stability of Electrolyte Supported Cells

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