Exchange Current Density of Solid Oxide Fuel Cell Electrodes

The calculation of the entropy production rate within an operational high temperature solid oxide fuel cell (SOFC) is necessary to design and improve heating and cooling strategies. However, due to a lack of information, most of the studies are limited to empirical relations, which are not in line with the more general approach given by non-equilibrium thermodynamics (NET). The SOFC 1D-model presented in this study is based on non-equilibrium thermodynamics and we parameterize it with experimental data and data from molecular dynamics (MD). The validation of the model shows that it can effectively describe the behavior of a SOFC at 1300 K. Moreover, we show that the highest entropy production is present in the electrolyte and the catalyst layers, and that the Peltier heat transfer is considerable for the calculation of the heat flux in the electrolyte and cannot be neglected. To our knowledge, this is the first validated model of a SOFC based on non-equilibrium thermodynamics and this study can be extended to analyze SOFCs with other solid oxide electrolytes, with perovskites electrolytes or even other electrochemical systems like solid oxide electrolysis cells (SOECs).

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“…A more detailed discussion, can be found in [50]. We calculate j i 0 with an approach from Yonekura et al [51]:…”

Section: Mathematical Description Of the Clsmentioning

confidence: 99%

Impact of Multi-Causal Transport Mechanisms in an Electrolyte Supported Planar SOFC with (ZrO2)x−1(Y2O3)x Electrolyte

Huerta¹,

Flasbart²,

Marquardt³

et al. 2018

Entropy

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“…At a relatively large current density, the potential of the cell would be expected to decrease more rapidly and in a non-linear fashion, indicating the dominance of concentration polarization. A high current density requires fast consumption of the reactant gas (oxygen) and also fast exhaustion of the products, possibly exceeding the gas transport rate in the electrode, both due to the oxygen-depleted diffusion film adjacent to the active sites and due to transport limitation in the fine pores [18,19].…”

mentioning

confidence: 99%

Single-Cell Tests to Explore the Reliability of Sofc Installations Operating Offshore

et al. 2020

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This paper studies the robustness of off-shore solid oxide fuel cell (SOFC) installations and the nature and causes of possible cell degradation in marine environments. Two important, cathode-related, impediments to ensuring SOFC reliability in off-shore installations are: cathode degradation due to salt contamination and oxygen depletion in the air supply. Short-term and long-term tests show the effect of salt contamination in the cathode feed on cell performance, and reveal the underlying cause of the degradation seen. SEM/X-ray Diffraction/(XRD) analyses made it possible to identify salt taken up in the cathode microstructure after the short-term testing while the macroscopic cell structure remained intact after the short-term tests. The long-term degradation was found to be more severe, and SEM images showed delamination at the cathode/electrolyte interface with salt present, something that was not seen after long-term testing without salt. The effect of oxygen depletion on the performance was also determined at three different temperatures using I-V curves.

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“…The activation polarization loss η act is determined by the Tafel equation ( Yonekuraa et al., 2011 ):

where n-no. of electrons transferring during cell reaction.…”

Section: Methodsmentioning

confidence: 99%

Parametric sensitivity analysis for a natural gas fueled high temperature tubular solid oxide fuel cell

Kalra¹,

Rishabh²,

Kumar³

2020

Heliyon

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For more than the last two decades, there has been research going on to develop advanced energy technologies involving minimum environmental pollution, to replace the conventional fossil energy systems. Solid oxide fuel cells (SOFCs) are one of the most promising, eco-friendly and efficient means for the generation of electricity to meet the future energy requirements. This research work focuses on the parametric sensitivity analysis for natural gas fueled high temperature tubular SOFC. Firstly, for the tubular SOFC, a one-dimensional radially symmetrical model has been developed and solved using the finite-difference method. Then, the effect of the variation of important operational and design parameters on its performance has been analyzed. The parameters typically include composition, inlet fuel temperature, pressure, length of SOFC tube and thicknesses of its components. The composition is expressed as steam to methane ratio and it has been observed that the voltage and power density developed by the SOFC diminishes as the ratio increases. Further, a change in the inlet fuel pressure of the tubular SOFC has no pronounced influence on the voltage and power density developed. On the other hand, with an increase in the inlet fuel temperature, a small improvement in these performance characteristics is exhibited. The axial length of the tubular SOFC does conspicuously influence its performance characteristics but solely at current densities greater than 4000A/m 2 . An increase in the thickness of its components results in a reduction in its voltage and power density developed. The largest decline in these performance characteristics with the increase in thickness is observed for electrolyte followed by cathode and anode respectively.

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Exchange Current Density of Solid Oxide Fuel Cell Electrodes

Cited by 56 publications

References 10 publications

Impact of Multi-Causal Transport Mechanisms in an Electrolyte Supported Planar SOFC with (ZrO2)x−1(Y2O3)x Electrolyte

Impact of Multi-Causal Transport Mechanisms in an Electrolyte Supported Planar SOFC with (ZrO2)x−1(Y2O3)x Electrolyte

Single-Cell Tests to Explore the Reliability of Sofc Installations Operating Offshore

Parametric sensitivity analysis for a natural gas fueled high temperature tubular solid oxide fuel cell

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