Influence of pore formers on slurry composition and microstructure of tape cast supporting anodes for SOFCs

Sanson, Alessandra; Pinasco, Paola; Roncari, E.

doi:10.1016/j.jeurceramsoc.2007.10.001

Cited by 138 publications

(63 citation statements)

References 19 publications

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“…Forming large pore necks appear to be a general challenge when using pyrolyzable pore formers; 21,22 novel pore forming approaches in combination with thermoplastic feedstocks should therefore be investigated. Increasing the particle size of the 3Y-TZP powder showed promising results, including a fraction of even coarser powders could hence further improve the gas permeability.…”

Section: Discussionmentioning

confidence: 99%

Graphite and PMMA as pore formers for thermoplastic extrusion of porous 3Y-TZP oxygen transport membrane supports

Haugen

Gurauskis

Kaiser

et al. 2017

Journal of the European Ceramic Society

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A gas permeable porous support is a crucial part of an asymmetric oxygen transport membrane (OTM). Here, we develop feedstocks for thermoplastic extrusion of tubular, porous 3Y-TZP (partially stabilized zirconia polycrystals, (Y2O3)0.03(ZrO2)0.97)) ceramics, using graphite and/or polymethyl methacrylate (PMMA) as pore formers. The influence of pore former content and type, 3Y-TZP particle size and support sintering temperature on the microstructure, porosity and gas permeability were studied. Using at least 40 vol% pore former, consisting of graphite and PMMA in the volume ratio 2:1, tubes with gas permeability exceeding the target of 10 -14 m 2 are obtained. In the temperature range 1250-1400°C the support gas permeability is insensitive to the sintering temperature, and the feedstocks shrink more than 15 % during sintering, making them ideal for cosintering with functional OTM layers. This demonstrates the suitability of thermoplastic extrusion for fabrication of porous 3Y-TZP OTM supports, or for other technologies requiring porous ceramics.

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Section: Discussionmentioning

confidence: 99%

Graphite and PMMA as pore formers for thermoplastic extrusion of porous 3Y-TZP oxygen transport membrane supports

Haugen

Gurauskis

Kaiser

et al. 2017

Journal of the European Ceramic Society

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“…Typically, highly porous Ni-YSZ cermets with porosity levels around 40-50 vol.% are required to ensure an efficient three-phase-boundary (TPB) among electrode, electrolyte and gas phase.17 Commonly, carbon black, flake graphite, spherical polymethyl methacrylate, rice starch or sucrose have been used to produce similar porous structures. [18][19][20][21][22] In this work, the use of corn starch as a pore forming agent in an extrusion process is addressed for the first time. The planned research work entails the mixture of dissimilar powders in a relatively wide range of sizes and shapes, which constitutes a particular issue not very common in conventional PEM.…”

Section: Introductionmentioning

confidence: 99%

High-performance Ni–YSZ thin-walled microtubes for anode-supported solid oxide fuel cells obtained by powder extrusion moulding

et al. 2016

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Aiming at the fabrication of microtubular anode-supports for Solid Oxide Fuel Cells (SOFCs) applications, this contribution deals with the production of Ni-YSZ thin-walled tubes (<1 mm thickness) via Powder Extrusion Moulding (PEM). The overall method has been optimized with an emphasis on the effect of NiO particle size using two commercial NiO powders with mean sizes of 0.7 and 8 μm. A thermoplastic binder system based on polypropylene (PP), paraffin wax (PW) and stearic acid (SA) in a volume ratio of 50, 46 and 4, respectively, was used along with corn starch as a pore forming agent. Different feedstocks with solid loadings varying from 45 to 65 vol.% were processed and characterized to determine the optimal formulation. Typically, the mixtures exhibited a pseudoplastic behaviour from 100 to 1000 s-1. Feedstocks with finer NiO particles had the most balanced properties for PEM purpose and an optimal powder volume content of 65 vol.% was established. After extrusion and debinding steps, defect-free and constant cross-section tubes with 15 mm of length and 4 mm of nominal diameter were obtained. Final microstructure and DC conductivity were found to be closely linked to the NiO particle size, yielding a higher amount of open porosity and a better performance when using finer NiO powder. Based on this study, packing mechanism was found to be likely limited by the contribution of steric hindrances when dissimilar and coarse powder are mixed, which may play a decisive role in order to set tailored formulations. IntroductionSolid Oxide Fuel Cells (SOFCs) have emerged as an alternative to conventional power generators because of their high conversion efficiency and environmentally friendly performance while operating between 700 and 1000 °C. The most common configuration consists of a Ni-YSZ anode, a YSZ electrolyte and a lanthanum strontium-doped manganite (LSM) cathode.1,2 Among the different geometric designs of SOFCs, there is an increasing tendency to develop tubular devices because of their better thermo-mechanical properties, sealing simplicity, good thermal shock resistance, rapid start-up/shut-down time and excellent power cycling.3 Additionally, current technology is progressing towards microtubular stacks (MT-SOCF) owing to the enhanced volumetric power density, inversely proportional to diameter.4,5 On this matter, majority of recent works are heading for electrode-supported designs with thinner electrolytes to reduce the operation temperature, and thereby extending the range of SOFCs applications into mobile and portable fields.3 Specifically, anode-supported configurations have been on particular interest to overcome the issues associated with the consolidation of a dense electrolyte layer on the traditionally used cathodesupports.6-10 Nevertheless, in order to expedite the commercialization of MT-SOFCs systems, cell costs need to be remarkably reduced. In this way, the fabrication method of the support still remains as one of the major challenges, as well as the improvement of overall cell efficiency ...

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“…% (as pore former) using an agate mortar to prepare the anode-supported green pellets [11,22]. The mixture was then ground and sieved through 212 µm woven wire to obtain a fine powder.…”

Section: Methodsmentioning

confidence: 99%

“…Insufficient porosity may limit the catalytic activity of the anode during the electrochemical performance test. Therefore, the addition of carbon black as the pore former in the NiO-SDCC pellets is considerably important to improve the porosity of anodes [22,29].…”

Section: Microstructure and Porosity Ofmentioning

confidence: 99%

INFLUENCE OF SINTERING TEMPERATURE ON NiO-SDCC ANODE FOR LOW-TEMPERATURE SOLID OXIDE FUEL CELLS (LT-SOFCs)

Mahmud

Muchtar²,

Somalu³

2016

Ceramics - Silikaty

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Influence of pore formers on slurry composition and microstructure of tape cast supporting anodes for SOFCs

Cited by 138 publications

References 19 publications

Graphite and PMMA as pore formers for thermoplastic extrusion of porous 3Y-TZP oxygen transport membrane supports

Graphite and PMMA as pore formers for thermoplastic extrusion of porous 3Y-TZP oxygen transport membrane supports

High-performance Ni–YSZ thin-walled microtubes for anode-supported solid oxide fuel cells obtained by powder extrusion moulding

INFLUENCE OF SINTERING TEMPERATURE ON NiO-SDCC ANODE FOR LOW-TEMPERATURE SOLID OXIDE FUEL CELLS (LT-SOFCs)

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