Factors Governing Oxygen Reduction in Solid Oxide Fuel Cell Cathodes

Adler, Stuart B.

doi:10.1021/cr020724o

Cited by 2,215 publications

(1,685 citation statements)

References 323 publications

(734 reference statements)

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“…However, with surface exchange and transport phenomena enabled, the effective TPB length is extended to the total active TPB area that is actually present in electrode-electrolyte interfaces. Surface exchange and transport phenomena, which is comprised of many physical absorption and transport processes in the vicinity of the TPB [22], was approximated in the current model by considering gas particles that percolated to a location one cell removed from an electronic-ionic conducting material interface to count as completing the formation of the TPB at that point. This was the only aspect in which the gas phase was treated differently.…”

Section: Model Descriptionmentioning

confidence: 99%

“…A recent visualization study by Wilson et al [14] has begun to provide mechanistic insights through investigation of the electrode microstructural and compositional parameters such as tortuosity, interfacial adhesion, and interconnectivity in an effort to provide greater insight and improved detail with regard to these factors and how they affect percolation in the electrode. Reaction mechanisms involved in surface exchange and transport phenomena at an SOFC cathode [22].…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the percolation of the gas phase through the electrode has been investigated and shown to have a marked impact on the formation of active TPBs in the electrode. The effects of the gas phase physically extend beyond the gaseous pathways in the electrodes themselves, as the gaseous reactant and product phases are subject to surface exchange and transport phenomena, as discussed in [22] and modeled in [21], and shown in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling and comparison to literature data of composite solid oxide fuel cell electrode–electrolyte interface conductivity

Martinez¹,

Brouwer²

2010

Journal of Power Sources

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a b s t r a c tA Monte Carlo percolation model previously used to characterize Triple Phase Boundary (TPB) formation in composite SOFC electrode-electrolyte interfaces has been augmented to allow for investigation of the effects of composition, gas-phase percolation, and surface exchange and transport phenomena on the overall conductivity of these electrode-electrolyte interfaces. The model has been utilized to replicate the results of a previous modeling effort, with similar assumptions and application to an SOFC electrode electrolyte interface. Although the models are similar in many aspects, their key differences allow equivalent predictions of the behavior of overall electrode conductivity as a function of electrode composition, thereby verifying the assumptions and overall approach of the current model. The validity of omitting charge-transfer and activation resistances when comparing overall interfacial conductivity trends is confirmed. The current model is then used to simulate several experimental results. The comparisons among these results show the importance of including gas-phase percolation physics and surface exchange and transport phenomena features in the model. Including gas-phase percolation and these surface phenomena can significantly alter the predictions of conductivity behavior and better predicts experimental observations, particularly at low and high electronic conductor volume fractions.

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Section: Model Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modeling and comparison to literature data of composite solid oxide fuel cell electrode–electrolyte interface conductivity

Martinez¹,

Brouwer²

2010

Journal of Power Sources

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“…[1][2][3][4] As fuel cell electrodes, MIECs have the potential to broaden the electrochemical reaction zone beyond the triple-phase boundary at which electrode, electrolyte and gas phase are in simultaneous contact. That is, in a conventional fuel cell, electrochemical reactions are limited to triple-phase boundaries because only to and from such locations can ions, electrons and gas molecules each be transported.…”

Section: Introductionmentioning

confidence: 99%

Surface reaction and transport in mixed conductors with electrochemically-active surfaces: a 2-D numerical study of ceria

Ciucci

Chueh

Goodwin

et al. 2011

Phys. Chem. Chem. Phys.

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A two-dimensional, small-bias model has been developed for describing transport through a mixed ionic and electronic conductor (MIEC) with electrochemically-active surfaces, a system of particular relevance to solid oxide fuel cells. Utilizing the h-adaptive finite-element method, we solve the electrochemical potential and flux for both ionic and electronic species in the MIEC, taking the transport properties of Sm 0.15 Ce 0.85 O 1.925Àd (SDC15). In addition to the ionic flux that flows between the two sides of the cell, there are two types of electronic fluxes: (1) cross-plane current that flows in the same general direction as the ionic current, and (2) in-plane current that flows between the catalytically-active MIEC surface and the metal current collectors. From an evaluation of these fluxes, the macroscopic interfacial resistance is decomposed into an electrochemical reaction resistance and an electron diffusion-drift resistance, the latter associated with the in-plane electronic current. Analysis of the experimental data for the interfacial resistance for hydrogen electro-oxidation on SDC15 having either Pt or Au current collectors (W. Lai and S. M. Haile, J. Am. Ceram. Soc., 2005, 88, 2979-2997; W. C. Chueh, W. Lai and S. M. Haile, Solid State Ionics, 2008Ionics, , 179, 1036Ionics, -1041 indicates that surface reaction rather than electron migration is the overall rate-limiting step, and suggests furthermore that the surface reaction rate, which has not been directly measured in the literature, scales with p À1=4 O 2 . The penetration depth for the in-plane electronic current is estimated at 0.6 mm for the experimental conditions of interest to SDC15, and is found to attain a value as high as 4 mm within the broader range of computational conditions.

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“…Mixed ionic‐electronic composite electrodes have been proposed as alternatives to the simple metal cermets 37, 38. Their use in SOFCs has many potential benefits and can improve their performance significantly 34, 39, 40.…”

Section: Dir‐sofc Model Descriptionmentioning

confidence: 99%

Detailed Multi‐dimensional Modeling of Direct Internal Reforming Solid Oxide Fuel Cells

et al. 2016

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Fuel flexibility is a significant advantage of solid oxide fuel cells (SOFCs) and can be attributed to their high operating temperature. Here we consider a direct internal reforming solid oxide fuel cell setup in which a separate fuel reformer is not required. We construct a multidimensional, detailed model of a planar solid oxide fuel cell, where mass transport in the fuel channel is modeled using the Stefan‐Maxwell model, whereas the mass transport within the porous electrodes is simulated using the Dusty‐Gas model. The resulting highly nonlinear model is built into COMSOL Multiphysics, a commercial computational fluid dynamics software, and is validated against experimental data from the literature. A number of parametric studies is performed to obtain insights on the direct internal reforming solid oxide fuel cell system behavior and efficiency, to aid the design procedure. It is shown that internal reforming results in temperature drop close to the inlet and that the direct internal reforming solid oxide fuel cell performance can be enhanced by increasing the operating temperature. It is also observed that decreases in the inlet temperature result in smoother temperature profiles and in the formation of reduced thermal gradients. Furthermore, the direct internal reforming solid oxide fuel cell performance was found to be affected by the thickness of the electrochemically‐active anode catalyst layer, although not always substantially, due to the counter‐balancing behavior of the activation and ohmic overpotentials.

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Factors Governing Oxygen Reduction in Solid Oxide Fuel Cell Cathodes

Cited by 2,215 publications

References 323 publications

Modeling and comparison to literature data of composite solid oxide fuel cell electrode–electrolyte interface conductivity

Modeling and comparison to literature data of composite solid oxide fuel cell electrode–electrolyte interface conductivity

Surface reaction and transport in mixed conductors with electrochemically-active surfaces: a 2-D numerical study of ceria

Detailed Multi‐dimensional Modeling of Direct Internal Reforming Solid Oxide Fuel Cells

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