Computation of TPB length, surface area and pore size from numerical reconstruction of composite solid oxide fuel cell electrodes

Kenney, Ben; Valdmanis, Mikelis; Baker, Craig J.; Pharoah, Jon G.; Karan, Kunal

doi:10.1016/j.jpowsour.2008.12.145

Cited by 166 publications

(156 citation statements)

References 21 publications

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“…Equations (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) can be used to predict the effective properties of the composite electrode using the mono-particle size distribution of each type of material. Equations (20)(21)(22)(23)(24)(25)(26)(27)(28)(29) can be used to predict the effective properties of the composite electrode using the poly-dispersed particle sizes.…”

Section: Resultsmentioning

confidence: 99%

“…In our previous paper [17], the validity of Equations (20-23) were carefully checked by comparing the calculated results with computer simulation results that were obtained using the random packing reconstruction model [9].…”

Section: Lscf + Ysz Composite Cathode With Poly-dispersed Particle Sizesmentioning

confidence: 99%

“…In the past decades, parametric studies for the composite electrodes have been widely conducted by many researchers through experiments [5,6], random packing reconstruction methods [7][8][9] and percolation theory [10][11][12]: (i) the experimental methods rely primarily on the stereological methods [5,13,14]. Recently, the focused ion-beam scanning electron microscopy has been attempted to obtain the high resolution 3D image of a composite electrode [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…Even so, the theoretical approaches are also necessary, because the experimental methods are still expensive and time consuming, and require hard-to-access facilities. The resolution of focused ion beam SEM is still a limiting factor, especially for electrodes of nano-particles; (ii) the random packing reconstruction methods are mainly based on the random packing of the spherical particles, in which a composite electrode is considered as a porous structure formed by randomly distributed spherical particles [7][8][9]; (iii) the percolation micro-models use the percolation theory and coordination number theory to represent the microstructure of a composite electrode developed by the random packing reconstruction methods [11]. The analytical expressions are derived to relate the electrode properties and the microstructure parameters [12,15].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Percolation Theory in Solid Oxide Fuel Cell Composite Electrodes with a Mixed Electronic and Ionic Conductor

Chen

Zhang

et al. 2013

Energies

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Percolation theory is generalized to predict the effective properties of specific solid oxide fuel cell composite electrodes, which consist of a pure ion conducting material (e.g., YSZ or GDC) and a mixed electron and ion conducting material (e.g., LSCF, LSCM or CeO 2 ). The investigated properties include the probabilities of an LSCF particle belonging to the electron and ion conducting paths, percolated three-phase-boundary electrochemical reaction sites, which are based on different assumptions, the exposed LSCF surface electrochemical reaction sites and the revised expressions for the inter-particle ionic conductivities among LSCF and YSZ materials. The effects of the microstructure parameters, such as the volume fraction of the LSCF material, the particle size distributions of both the LSCF and YSZ materials (i.e., the mean particle radii and the non-dimensional standard deviations, which represent the particle size distributions) and the porosity are studied. Finally, all of the calculated results are presented in non-dimensional forms to provide generality for practical application. Based on these results, the relevant properties can be easily evaluated, and the microstructure parameters and intrinsic properties of each material are specified.Keywords: solid oxide fuel cell; percolation theory; mixed electron and ion conductor; LSCF; coordination number; three-phase-boundary sites; electrochemically active sites

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Section: Resultsmentioning

confidence: 99%

Section: Lscf + Ysz Composite Cathode With Poly-dispersed Particle Sizesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Percolation Theory in Solid Oxide Fuel Cell Composite Electrodes with a Mixed Electronic and Ionic Conductor

Chen

Zhang

et al. 2013

Energies

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“…Finally, the effect of the level of grid surface refinement (octree, cut-cell, etc.) on the results is investigated for random porous media with polydisperse particle size distributions available in the literature [40,51].…”

Section: Numerical Resultsmentioning

confidence: 99%

Effective transport properties of the porous electrodes in solid oxide fuel cells

Choi

Berson

Pharoah

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part A:

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This article presents a numerical framework for the computation of the effective transport properties of solid oxide fuel cells (SOFCs) porous electrodes from three-dimensional (3D) constructions of the microstructure. Realistic models of the 3D microstructure of porous electrodes are first constructed from measured parameters such as porosity and particle size distribution. Then each phase in the model geometries is tessellated with a computational grid. Three different types of grids are considered: Cartesian, octree, and body-fitted/cut-cell with successive levels of surface refinement. Finally, a finite volume method is used to compute the effective transport properties in the three phases (pore, electron, and ion) of the electrode. To validate the numerical approach, results obtained with the finite volume method are compared to those calculated with a random walk simulation for the case of a body-centred cubic lattice of spheres. Then, the influence of the sample size is investigated for random geometries with monosized particle distributions. Finally, effective transport properties are calculated for model geometries with polydisperse particle size distributions similar to those observed in actual SOFC electrodes.

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Characterization of Spatial Distribution of Electrolyte in Molten Carbonate Fuel Cell Cathodes

et al. 2018

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High-resolution computed X-ray tomography (XCT) is applied in this study to characterize the microstructure of Molten Carbonate Fuel Cell (MCFC) cathodes after operation, where a "virgin cathode" formed by porous nickel has been in situ oxidized and infiltrated by liquid electrolyte. This technique extends state-of-the art methodology to characterize pores such as porosity analysis using Mercury porosimetry. XCT enables 3D imaging of the internal structure of the electrodes including all components present at the cathode side, particularly NiO, pores, and electrolyte. The quantitative 3D microstructure analysis based on high-resolution XCT provides topological information for each component and their mutual spatial distribution, which is significant for the enhancement of the MCFC performance. In particular, volume fraction, specific surface area, continuity of each phase, as well as the Triple Phase Boundary (TPB) density are calculated from the experimental data. The results indicate that superior properties of the multi-modal pore sized cathode, used in this study, can be attributed to the formation of three selfinterpenetrating networks of pathways for the transport of gasses, electrons, as well as ions throughout pores, NiO, and electrolyte, respectively.

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Computation of TPB length, surface area and pore size from numerical reconstruction of composite solid oxide fuel cell electrodes

Cited by 166 publications

References 21 publications

Percolation Theory in Solid Oxide Fuel Cell Composite Electrodes with a Mixed Electronic and Ionic Conductor

Percolation Theory in Solid Oxide Fuel Cell Composite Electrodes with a Mixed Electronic and Ionic Conductor

Effective transport properties of the porous electrodes in solid oxide fuel cells

Characterization of Spatial Distribution of Electrolyte in Molten Carbonate Fuel Cell Cathodes

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