Synthesis of Dispersed and Contiguous Nanoparticles in Solid Oxide Fuel Cell Electrodes

Sholklapper, Tal Z.; Jacobson, Craig P.; Visco, Steven J.; Jonghe, Lutgard C. De

doi:10.1002/fuce.200800030

Cited by 128 publications

(94 citation statements)

References 40 publications

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“…They claim this technique reduces the fabrication time by 6 -7 times, whilst increasing the electrodes surface area by 24%. Impregnating molten salts instead of dilute precursor solutions has been suggested as another way to efficiently deposit large quantities of active phases 77 .…”

Section: Impregnationmentioning

confidence: 99%

Evolution of the electrochemical interface in high-temperature fuel cells and electrolysers

et al. 2016

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Section: Impregnationmentioning

confidence: 99%

Evolution of the electrochemical interface in high-temperature fuel cells and electrolysers

et al. 2016

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“…One type of these systems, known as colloids, has nanoparticles (NPs) as its main component. Colloids systems are made of NPs dispersed in solids (Sholklapper et al 2008), liquids (e.g., ferrofluids) (Chandrasekar et al 2012), and in soft gel matrices (e.g. ferrogels) (Schexnailder and Schmidt 2009), among others.…”

Section: Introductionmentioning

confidence: 99%

Magnetic properties study of iron-oxide nanoparticles/PVA ferrogels with potential biomedical applications

et al. 2013

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A study of the magnetic behavior of maghemite nanoparticles (NPs) in polyvinyl alcohol (PVA) polymer matrices prepared by physical crosslinking is reported. The magnetic nanocomposites (ferrogels) were obtained by the in situ co-precipitation of iron salts in the presence of PVA polymer, and subsequently subjected to freezing-thawing cycles. The magnetic behavior of these ferrogels was compared with that of similar systems synthesized using the glutaraldehyde. This type of chemical crosslinking agents presents several disadvantages due to the presence of residual toxic molecules in the gel, which are undesirable for biological applications. Characteristic particle size determined by several techniques are in the range 7.9-9.3 nm. The iron oxidation state in the NPs was studied by X-ray absorption spectroscopy. Mössbauer measurements showed that the NP magnetic moments present collective magnetic excitations and superparamagnetic relaxations. The blocking and irreversibility temperatures of the NPs in the ferrogels, and the magnetic anisotropy constant, were obtained from magnetic measurements. An empirical model including two magnetic contributions (large NPs slightly departed from thermodynamic equilibrium below 200 K, and small NPs at thermodynamic equilibrium) was used to fit the experimental magnetization curves. A deviation from the superparamagnetic regime was observed. This deviation was explained on the basis of an interacting superparamagnetic model. From this model, relevant magnetic and structural properties were obtained, such as the magnitude order of the dipolar interaction energy, the NPs magnetic moment, and the number of NPs per ferrogel mass unit. This study contributes to the understanding of the basic physics of a new class of materials that could emerge from the PVA-based magnetic ferrogels.

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“…[1][2][3][4][5][6][7] The main reason is reduced polarization resistance, with corresponding increased power density, in comparison with conventional electrodes prepared via traditional mixing and sintering processes. The improved performance of infiltrated electrodes holds even at intermediate temperatures (500-800…”

mentioning

confidence: 99%

A Particle-Based Model for Effective Properties in Infiltrated Solid Oxide Fuel Cell Electrodes

Bertei

Pharoah

Gawel

et al. 2014

J. Electrochem. Soc.

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A modeling framework for the numerical reconstruction of the microstructure of infiltrated electrodes is presented in this study. A particle-based sedimentation algorithm is used to generate the backbone, while a novel packing algorithm is used to randomly infiltrate nanoparticles on the surface of backbone particles. The effective properties, such as the connected triple-phase boundary length, the effective conductivity, the effective diffusivity, are evaluated on the reconstructed electrodes by using geometric analysis, finite volume and random-walk methods, and reported in dimensionless form to provide generality to the results. A parametric study on the effect of the main model and operating parameters is performed. Simulations show that the critical loading (i.e., the percolation threshold) increases as the backbone porosity decreases and the nanoparticle diameter increases. Large triple-phase boundary length, specific surface area and good effective conductivity can be reached by infiltration, without detrimental effects on the effective transport properties in gas phase. Simulations reveal a significant sensitivity to the size and contact angle of infiltrated particles, suggesting that the preparation process of infiltrated electrodes should be properly tailored in order to obtain the optimized structures predicted by the model. In the last decade, much attention has been drawn toward nanostructured electrodes for solid oxide fuel cells (SOFCs) prepared via infiltration techniques.1-7 The main reason is reduced polarization resistance, with corresponding increased power density, in comparison with conventional electrodes prepared via traditional mixing and sintering processes. The improved performance of infiltrated electrodes holds even at intermediate temperatures (500-800• C), as demonstrated by a large number of experimental studies. [8][9][10][11][12][13] Other technological advantages are a wide choice of catalyst materials, a good adhesion and a reduced thermal expansion mismatch between the electrode and the electrolyte.3 On the other hand, the long-term stability and the fabrication cost of nanostructured electrodes still need to be properly addressed. 2,3The infiltration (or impregnation) technique involves the deposition of nanoparticles into a pre-sintered backbone of micrometer-size particles.1,3 The backbone is a skeletal structure typically composed of a single component, such as yttria-stabilized zirconia (YSZ) 5,8 or, in alternative, a mixed ionic-electronic conductor (e.g., lanthanum strontium cobalt ferrite LSCF).14 However, composite backbones, such as the usual lanthanum strontium manganite (LSM)/YSZ cathode, have also been used. 1,15 The sintering of the backbone is performed at high temperature in order to ensure structural stability of the electrode and good connection among backbone particles. 3 In the following step, nanoparticles are infiltrated in the backbone using different methods (such as metal salt precipitation, 2 nanoparticle dispersion, 16 molten salts) 1 and then sinte...

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Synthesis of Dispersed and Contiguous Nanoparticles in Solid Oxide Fuel Cell Electrodes

Cited by 128 publications

References 40 publications

Evolution of the electrochemical interface in high-temperature fuel cells and electrolysers

Evolution of the electrochemical interface in high-temperature fuel cells and electrolysers

Magnetic properties study of iron-oxide nanoparticles/PVA ferrogels with potential biomedical applications

A Particle-Based Model for Effective Properties in Infiltrated Solid Oxide Fuel Cell Electrodes

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