Gas Diffusion Impedance in Characterization of Solid Oxide Fuel Cell Anodes

Primdahl, S.; Mogensen, Mogens Bjerg

doi:10.1149/1.1392015

Cited by 365 publications

(350 citation statements)

References 22 publications

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“…The size of this arc and the n value were difficult to be determined from the impedance spectra measured at the OCV. In view of the low activation energy related to this arc, the fact that it appears at low frequencies of impedance spectra of all cells regardless of impregnation material, is in good agreement with the gas diffusion impedance, as described by Mogensen [37].…”

Section: Impedance Analysissupporting

confidence: 82%

NOx and propene conversion on La0.85Sr0.15MnO3+d/Ce0.9Gd0.1O1.95 symmetrical cells

Friedberg

2017

J. Electrochem. Sci. Eng.

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Section: Impedance Analysissupporting

confidence: 82%

NOx and propene conversion on La0.85Sr0.15MnO3+d/Ce0.9Gd0.1O1.95 symmetrical cells

Friedberg

2017

J. Electrochem. Sci. Eng.

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“…The impedance response from the LSC/CGO oxygen electrode has been approximated by a Gerisher-type response in the CNLS fitting routine in line with the work by Hjelm et al [15]; having a characteristic frequency of 100 Hz. Furthermore; gas diffusion and gas conversion resistance contributions as described by Primdahl and Mogensen have been approximated by two RQ-circuits having characteristic frequencies around 40 Hz and 2 Hz, respectively [30,31]. "Estimated uncertainty for the resistance values obtain via equivalent circuit modeling of IS  ±4 mΩcm2.…”

Section: Electrochemical Impedance Spectroscopy (Eis)mentioning

confidence: 99%

Ni/YSZ electrodes structures optimized for increased electrolysis performance and durability

et al. 2016

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Cermet Ni/YSZ electrodes are the most commonly applied fuel electrode for solid oxide cells (SOC) both when targeting solid oxide fuel cell (SOFC) applications and when used as solid oxide electrolysis cell (SOEC). In this work we report on the correlation between initial Ni/YSZ microstructure and the resulting electrochemical performance both initially and during long-term electrolysis testing at high current density and high p(H2O) inlet. Especially, this work focuses on microstructure optimization to hinder Ni mobility and migration during long-term operation and illustrates the key-role of electrode over-potential on the degradation of the Ni/YSZ electrodes in SOEC. We find that for long-term stability for electrolysis at high current densities and high p(H2O) the as-produced NiO/YSZ precursor electrode should be: 1) As dense as possible, 2) as fine particle and pore sized as possible and 3) the three phases (Ni, YSZ and pore phase) shall be size-matched and welldispersed. Applying such microstructure optimized Ni/YSZ electrode we show SOEC test results with long-term degradation rate as low as 0.3-0.4 %/kh at 1 A/cm 2 , 800 C and inlet gas mixture of p(H2O)/p(H2):90/10. This enables SOEC operation of such cell for more than 5 years below thermo-neutral potential at these operating conditions.

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“…In particular, we estimate the gas conversion resistance due to the stagnant diffusion layer outside the porous electrode in the open circuit condition, studied by Primdahl and Mogensen. 48 With the relatively high total gas flow rate of 300 ml/min (at 25…”

Section: Rb Fick(anodementioning

confidence: 99%

Multicomponent Gas Diffusion in Porous Electrodes

Jiang

Poizeau

et al. 2015

J. Electrochem. Soc.

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Multicomponent gas transport is investigated with unprecedented precision by AC impedance analysis of porous YSZ anodesupported solid oxide fuel cells. A fuel gas mixture of H 2 -H 2 O-N 2 is fed to the anode, and impedance data are measured across the range of hydrogen partial pressure (10-100%) for open circuit conditions at three temperatures (800 • C, 850 • C and 900 • C) and for 300 mA applied current at 800 • C. For the first time, analytical formulae for the diffusion resistance (R b ) of three standard models of multicomponent gas transport (Fick, Stefan-Maxwell, and Dusty Gas) are derived and tested against the impedance data. The tortuosity is the only fitting parameter since all the diffusion coefficients are known. Only the Dusty Gas Model leads to a remarkable data collapse for over twenty experimental conditions, using a constant tortuosity consistent with permeability measurements and the Bruggeman relation. These results establish the accuracy of the Dusty Gas Model for multicomponent gas diffusion in porous media and confirm the efficacy of electrochemical impedance analysis to precisely determine transport mechanisms. The Solid Oxide Fuel Cell (SOFC) is currently the highesttemperature fuel cell in development and can be operated over a wide temperature range from 600• C-1000• C allowing a number of fuels to be used. To operate at such high temperatures, the electrolyte is a thin, nonporous solid ceramic membrane that is conductive to charge carrier, O 2− ions. The operating efficiency in generating electricity is among the highest of the fuel cells at about 60%.1 Furthermore, the high operating temperature allows cogeneration of high-pressure steam that can be used in many applications. Combining a hightemperature SOFC with a turbine into a hybrid fuel cell further increases the overall efficiency of generating electricity with a potential of an efficiency of more than 70%.1 Therefore, it is a very promising alternative energy source that could potentially be used for home heating or large scale electricity production in the future.Solid oxide fuel cell consists of a porous cathode, an electrolyte, a porous anode and interconnects. Two different types have been explored in the development of SOFC, the electrolyte supported cell and the electrode supported cell. In the former, electrolyte is the thickest and serves as the mechanical support for the whole cell. However, due to the high Ohmic resistance of the relatively thick electrolyte layer, the electrolyte supported design has been gradually replaced by the new electrode supported cells, in which one of the porous electrodes is the supporting structure. Moreover, since cathode supported cell usually gives higher resistance, and is much harder to fabricate due to the mismatched thermal expansion coefficient of cathode support and functional layer, the anode supported cell (ASC) is the most widely accepted design in current SOFC research.The solid oxide fuel cell is operated with fuel and oxidant being continuously fed from two sides of the ce...

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Gas Diffusion Impedance in Characterization of Solid Oxide Fuel Cell Anodes

Cited by 365 publications

References 22 publications

NOx and propene conversion on La0.85Sr0.15MnO3+d/Ce0.9Gd0.1O1.95 symmetrical cells

NOx and propene conversion on La0.85Sr0.15MnO3+d/Ce0.9Gd0.1O1.95 symmetrical cells

Ni/YSZ electrodes structures optimized for increased electrolysis performance and durability

Multicomponent Gas Diffusion in Porous Electrodes

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