Some more considerations on the optimization of cermet solid oxide fuel cell electrodes

Costamagna, Paola; Costa, Paolo; Arato, Elisabetta

doi:10.1016/s0013-4686(97)00262-4

Cited by 64 publications

(43 citation statements)

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“…In such a case, the mathematical problem represented by Eqs. 1-3 becomes one-dimensional, allowing for an analytical solution of the ionic potential along the thickness of the electrode as reported in other studies, for example, by Costamagna et al 36,54 The total current density i f lat tot is determined by considering the electrode resistance R ed and the electrolyte resistance t ey /σ O in series as follows:…”

Section: Modellingmentioning

confidence: 99%

“…In a flat electrode the ohmic overpotential profile is opposite to the activation overpotential distribution, 36 being 0 at the electrolyte interface and increasing exponentially along the electrode thickness. 36,54 Such an exponential profile is mathematically mimicked by the following equation: [14] which is used in Figure 8a to draw the outline of the pillar, resulting in a rounded terrace shape which resembles the ohmic overpotential distribution in a flat configuration. 36,54 In Eq.…”

Section: Microstructural Properties Of the Composite Electrode Domain-mentioning

confidence: 99%

“…36,54 Such an exponential profile is mathematically mimicked by the following equation: [14] which is used in Figure 8a to draw the outline of the pillar, resulting in a rounded terrace shape which resembles the ohmic overpotential distribution in a flat configuration. 36,54 In Eq. 14, t r is a roundness characteristic length: the smaller t r , the sharper the outline.…”

Section: Microstructural Properties Of the Composite Electrode Domain-mentioning

confidence: 99%

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Guidelines for the Rational Design and Engineering of 3D Manufactured Solid Oxide Fuel Cell Composite Electrodes

Bertei

Tariq

Yufit

et al. 2016

J. Electrochem. Soc.

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The growth of 3D printing has opened the scope for designing microstructures for solid oxide fuel cells (SOFCs) with improved power density and lifetime. This technique can introduce structural modifications at a scale larger than particle size but smaller than cell size, such as by inserting electrolyte pillars of ∼5-100 μm. This study sets the minimum requirements for the rational design of 3D printed electrodes based on an electrochemical model and analytical solutions for functional layers with negligible electronic resistance and no mixed conduction. Results show that this structural modification enhances the power density when the ratio k eff between effective conductivity and bulk conductivity of the ionic phase is smaller than 0.5. The maximum performance improvement is predicted as a function of k eff . A design study on a wide range of pillar shapes indicates that improvements are achieved by any structural modification which provides ionic conduction up to a characteristic thickness ∼10-40 μm without removing active volume at the electrolyte interface. The best performance is reached for thin (<∼2 μm) and long (>∼80 μm) pillars when the composite electrode is optimised for maximum three-phase boundary density, pointing toward the design of scaffolds with well-defined geometry and fractal structures. Many studies in the literature have recognised the importance of the electrode microstructure in affecting the power density and the lifetime of solid oxide fuel cells (SOFCs).1-7 Significant enhancements in power density have been achieved through the statistical control of the microstructural properties by tuning porosity, 8,9 volume fractions, 2,8,10 particle size 11-13 and even tortuosity of the phases.14 However, nowadays the design of the electrode microstructure can be optimised with unprecedented precision through the advent of 3D printing and additive manufacturing techniques. 15-17Additive manufacturing allows for the development of electrodes with 3D architectures, thus going beyond what conventional fabrication techniques, such as tape casting and screen printing, can produce. The exploitation of 3D additive manufacturing has been successfully applied by the battery community [18][19][20] and the implementation of this approach to SOFCs is currently under investigation.15,21 One of the most promising applications consists of the insertion of ionconducting pillars connected to the electrolyte 15,[22][23][24][25] as reported in Figure 1. Such a modification can be regarded as the mesoscale structural control of electrode microstructure, where the term mesoscale here refers to a dimension larger than the typical constituent particle size (<1 μm) but smaller than the characteristic length of the cell, that is, falling in the order of 5-100 μm.26 Ideally, 3D printing offers the opportunity to controllably manufacture pillars of any shape, with the desired geometric and spacing requirements, in order to provide a preferential pathway for ionic conduction. 22,25 It is important to note that this mesos...

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Section: Modellingmentioning

confidence: 99%

Section: Microstructural Properties Of the Composite Electrode Domain-mentioning

confidence: 99%

Section: Microstructural Properties Of the Composite Electrode Domain-mentioning

confidence: 99%

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Guidelines for the Rational Design and Engineering of 3D Manufactured Solid Oxide Fuel Cell Composite Electrodes

Bertei

Tariq

Yufit

et al. 2016

J. Electrochem. Soc.

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“…Our theoretical investigation is based on a validated electrochemical model developed for a random-packing Ni-YSZ single-layer HT-SOFC anode [16,[32][33][34], updated for application to IT-SOFCs. The model is thus applied in the same form to both the AL and SL layers.…”

Section: Introductionmentioning

confidence: 99%

Modeling Analysis of Bi-Layer Ni-(ZrO2)x(Y2O3)1−x Anodes for Anode-Supported Intermediate Temperature-Solid Oxide Fuel Cells

2014

Self Cite

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Abstract:Intermediate temperature-solid oxide fuel cell (IT-SOFC) Ni-(ZrO 2 ) x (Y 2 O 3 ) 1−x (Ni-YSZ) anodes formed by two layers, with different thicknesses and morphologies, offer the possibility of obtaining adequate electrochemical performance coupled to satisfactory mechanical properties. We investigate bi-layered Ni-YSZ anodes from a modeling point of view. The model includes reaction kinetics (Butler-Volmer equation), mass transport (Dusty-Gas model), and charge transport (Ohm's law), and allows to gain an insight into the distribution of the electrochemical reaction within the electrode. Additionally, the model allows to evaluate a reciprocal overall electrode resistance 1/R p ≈ 6 S· cm −2 for a bi-layer electrode formed by a 10 µm thick active layer (AL) composed of 0.25 µm radius Ni and YSZ particles (34% vol. Ni), coupled to a 700 µm thick support layer (SL) formed by 0.5 µm radius Ni and YSZ particles (50% vol. Ni), and operated at a temperature of 1023 K. Simulation results compare satisfactorily to literature experimental data. The model allows to investigate, in detail, the effect of morphological and geometric parameters on the various sources of losses, which is the first step for an optimized electrode design.

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“…TPBs can be regarded as the sintering necks among heterogeneous particles of the sintered particle packing beds. To maximize the TPB lengths of composite SOC electrodes is the main task of the electrode design and optimization [6]. microstructure and TPBs analytically [28][29][30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Design and Optimization of Composite Electrodes in Solid Oxide Cells

Fang

Chan

2012

Fuel Cells

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The performance of solid oxide cells (SOCs) heavily relies on the population of three‐phase boundaries (TPBs) in the composite electrodes. In this study, SOC composite electrodes are described by percolating binary particle aggregates that are constructed from random loose packing models and classical sintering theories. Summed perimeters of the sintering necks represent the total TPB lengths. A case study has been carried out on lanthanum strontium manganite (LSM)–yttria‐stabilized zirconia (YSZ) composite electrodes. By employing three‐dimensional data that are converted from relevant two‐dimensional data, the TPB length of baseline LSM–YSZ electrodes investigated in this study is 35.4 μm μm–3. The parametric and sensitivity analyses show the changes of TPB lengths in functions of the weight fraction of powders, particle size and particle size ratio of powders, void fraction of electrodes, and density of materials. In the case of baseline LSM–YSZ electrodes, proper electrode design and optimization would result in 2–3 times of the enlargement of TPBs. Technical guidelines on the design and optimization of SOC composite electrodes are proposed.

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Some more considerations on the optimization of cermet solid oxide fuel cell electrodes

Cited by 64 publications

References 5 publications

Guidelines for the Rational Design and Engineering of 3D Manufactured Solid Oxide Fuel Cell Composite Electrodes

Guidelines for the Rational Design and Engineering of 3D Manufactured Solid Oxide Fuel Cell Composite Electrodes

Modeling Analysis of Bi-Layer Ni-(ZrO2)x(Y2O3)1−x Anodes for Anode-Supported Intermediate Temperature-Solid Oxide Fuel Cells

Design and Optimization of Composite Electrodes in Solid Oxide Cells

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