Towards the 3D Modelling of the Effective Conductivity of Solid Oxide Fuel Cell Electrodes – Validation against experimental measurements and prediction of electrochemical performance

Rhazaoui, K.; Cai, Qiong; Kishimoto, Masashi; Tariq, Farid; Somalu, Mahendra Rao; Adjiman, Claire S.; Brandon, Nigel P.

doi:10.1016/j.electacta.2015.04.005

Cited by 25 publications

(13 citation statements)

References 34 publications

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“…The original BCSA for electrostatics has been validated in detail [31]. In principle, that validation should also apply to steady-state electric conduc- It is known that the simulation cell must be sufficiently large to obtain reliable estimation of the effective conductivity [57,58]. We investigate the effect of the cell size on the effective conductivity with a constant grain radius of 0.5 μm.…”

Section: Validation Of the Effective Conductivity Calculation Methodsmentioning

confidence: 99%

Phase field modeling of microstructure evolution and concomitant effective conductivity change in solid oxide fuel cell electrodes

Lei

Cheng

Wen

2017

Journal of Power Sources

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Microstructure evolution plays an important role in the performance degradation of SOFC electrodes. In this work, we propose a much improved phase field model to simulate the microstructure evolution in the electrodes of solid oxide fuel cell. We demonstrate that the tunability of the interfacial energy in this model has been significantly enhanced. Parameters are set to fit for the interfacial energies of a typical Ni-YSZ anode, an LSM-YSZ cathode and an artificial reference electrode, respectively. The contact angles at various triple junctions and the microstructure evolutions in two dimensions are calibrated to verify the model. As a demonstration of the capabilities of the model, three dimensional microstructure evolutions are simulated applying the model to the three different electrodes. The time evolutions of grain size and triple phase boundary density are analyzed. In addition, a recently proposed bound charge successive approximation algorithm is employed to calculate the effective conductivity of the electrodes during microstructure evolution. The effective conductivity of all electrodes are found to decrease during the microstructure evolution, which is attributed to the increased tortuosity and the loss of percolated volume fration of the electrode phase.

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Section: Validation Of the Effective Conductivity Calculation Methodsmentioning

confidence: 99%

Phase field modeling of microstructure evolution and concomitant effective conductivity change in solid oxide fuel cell electrodes

Lei

Cheng

Wen

2017

Journal of Power Sources

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“…The anodic, or the cathodic half-reaction may take place anywhere within the continuous electrode-the influence of irregular morphological features of the microstructure is taken into consideration by introducing macroscopic parameters, which are, in general, distributed homogeneously within the modeled volume [15][16][17][18][19][20]. Fully three-dimensional models which employ a non-continuous computational domain to account for the irregular microstructure geometry are less common [21][22][23][24], since simulations performed using the continuous electrode theory require less computational resources. Furthermore, for a range of cases, the differential equations included in one-dimensional continuous-electrode models may be solved analytically, as proven by Costamagna [25] and Kulikovsky [26].…”

Section: Introductionmentioning

confidence: 99%

A Three-Dimensional Microstructure-Scale Simulation of a Solid Oxide Fuel Cell Anode—The Analysis of Stack Performance Enhancement After a Long-Term Operation

et al. 2019

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In this research, we investigate the connection between an observed enhancement in solid oxide fuel cell stack performance and the evolution of the microstructure of its electrodes. A three dimensional, numerical model is applied to predict the porous ceramic-metal electrode performance on the basis of microstructure morphology. The model features a non-continuous computational domain based on the digital reconstruction obtained using focused ion beam scanning electron microscopy (FIB-SEM) electron nanotomography. The Butler–Volmer equation is used to compute the charge transfer at reaction sites, which are modeled as distinct locally distributed features of the microstructure. Specific material properties are accounted for using interpolated experimental data from the open literature. Mass transport is modeled using the extended Stefan–Maxwell model, which accounts for both the binary, and the Knudsen diffusion phenomena. The simulations are in good agreement with the experimental data, correctly predicting a decrease in total losses for the observed microstructure evolution. The research supports the hypothesis that the performance enhancement was caused by a systematic change in microstructure morphology.

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“…With the aid of the additional information available from the multiscale model, new performance optimization procedures may be envisaged. It is particularly interesting the concept of design‐led techniques , in which the micro‐structure characteristics of the electrodes are modified in order to fit the specific operating conditions which occur locally in the cell. With the improvement of the electrodes manufacturing techniques (e.g., infiltration, freeze‐casting) and local control of the morphology, it would in fact be possible to design an optimized electrode micro‐structure able to best fit the expected local operating conditions.…”

Section: Resultsmentioning

confidence: 99%

Development of a Multiscale SOFC Model and Application to Axially‐Graded Electrode Design

2019

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A multiscale model is built to understand how microscale characteristics and the thermo‐chemical and electrochemical phenomena, occurring in the electrode and electrolyte assembly, may affect the overall performance of a solid oxide fuel cell (SOFC) stack. This study presents the integration of two‐dimensional finite volume models: a 1D microscale model and a 1D (or 2D) macroscale (channel/cell) model. The new tool is calibrated against the experimental data of a short‐stack via a numerical procedure aiming at the minimisation of the mean square deviation of the model from the measured data. Subsequently, the distribution of electrochemical active thickness in a state‐of‐the‐art solid oxide cell channel is calculated; the result is limited between 3% and 7% of the electrode thickness. An axially graded electrode is studied by changing the particle radii in order to locally control the triple phase boundary length distribution along the cell channel. The performances of a four‐section graded electrode is estimated in comparison to a reference non‐graded electrode. The average current density increases by approximately 6% in the short‐stack. If such a graded design was introduced into a state‐of‐the‐art cogeneration system, the extrapolation of these results suggests that a power output increase up to 13.5% is attainable.

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Towards the 3D Modelling of the Effective Conductivity of Solid Oxide Fuel Cell Electrodes – Validation against experimental measurements and prediction of electrochemical performance

Cited by 25 publications

References 34 publications

Phase field modeling of microstructure evolution and concomitant effective conductivity change in solid oxide fuel cell electrodes

Phase field modeling of microstructure evolution and concomitant effective conductivity change in solid oxide fuel cell electrodes

A Three-Dimensional Microstructure-Scale Simulation of a Solid Oxide Fuel Cell Anode—The Analysis of Stack Performance Enhancement After a Long-Term Operation

Development of a Multiscale SOFC Model and Application to Axially‐Graded Electrode Design

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