Open-circuit voltage of ceria-based thin film SOFC supported on nano-porous alumina

Joo, Jong Hoon; Choi, Gyeong Man

doi:10.1016/j.ssi.2007.10.006

Cited by 50 publications

(24 citation statements)

References 24 publications

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“…30,31 The geometrical parameters required to calculate the conductivity of grain boundaries from circuit parameters are not conveniently known. A dielectric constant of~50 is obtained for the YDC thin films, which is close to the reported dielectric constant of ceria thin films in the literature.…”

Section: Resultsmentioning

confidence: 99%

High‐Temperature Electrical Conductivity Measurements on Nanostructured Yttria‐Doped Ceria Thin Films in Ozone

2011

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We have investigated how ozone affects high‐temperature electrical properties of nanostructured yttria‐doped ceria (YDC) thin films using impedance spectroscopy. It is found that predominantly ionic conductivity in the doped‐ceria lattice is not altered upon exposure to ozone. The grain boundaries in YDC ultra‐thin films, in contrast, exhibited a substantial increase in resistance in ozone‐rich environment. While activation energy for lattice conduction in ozone was similar to air, being close to 1 eV, grain boundary activation energy increased notably from ~1.3 eV in air to 1.7 eV in ozone. Also, we have investigated kinetics of resistance change in such thin films in air and in ozone ambient using galvanostatic measurements and found that the rapid resistance change observed in ozone was reversible. Mechanisms leading to the observation and implications for ozone‐ceria film surface interactions are discussed.

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Section: Resultsmentioning

confidence: 99%

High‐Temperature Electrical Conductivity Measurements on Nanostructured Yttria‐Doped Ceria Thin Films in Ozone

2011

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“…As cerâmicas porosas podem ser usadas em diversos campos de aplicações, tais como biomateriais para implantes ósseos [1-4], filtros de líquidos e gases [5,6], ânodo para células combustíveis de óxido sólido [7,8], entre outros [9]. Devido às suas inúmeras aplicações, estudos têm sido desenvolvidos para incrementar as técnicas de processamento dessas cerâmicas porosas, tais como: inclusão de fase orgânica [10,11]; método da réplica da esponja polimérica [12,13]; método do gelcasting associado à aeração [14,15]; entre outras [16,17].…”

Section: Introductionunclassified

Análise comparativa entre diferentes ensaios porosimétricos em alumina macroporosa

et al. 2018

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RESUMOCerâmicas macroporosas de alumina (Al 2 O 3 ) são estudadas devido às suas diversas aplicações como biomateriais para implantes ósseos, ânodos para célula combustível de óxido sólido, entre outras. Nesse sentido, a distribuição, tamanho e interconexão dos poros podem determinar características físicas e mecânicas dessas cerâmicas. Assim sendo, o objetivo desse trabalho foi analisar e comparar diferentes métodos de caracterizações porosimétricas em amostras macroporosas de Al 2 O 3 . Para isso, os métodos analisados foram intrusão de mercúrio (PIM), método de Arquimedes (MA), análise de micrografias (AM) e ressonância magnética nuclear com pulsos de radiofrequência Carr-Purcell-Meiboom-Gill ( 1 H-RMN -CPMG). Amostras macroporosas de Al 2 O 3 foram obtidas pelo método de gelcasting modificado pela incorporação de esferas de polietileno, em diferentes quantidades. Os resultados foram tratados matematicamente e correlacionados pelo coeficiente de Pearson. As principais vantagens do MA foram a rapidez e a simplicidade na obtenção da porosidade aparente. No entanto, curvas de distribuição de tamanho de poros não são obtidas por esse método. As distribuições dos tamanhos dos poros obtidas por 1 H-RMN -CPMG foram semelhantes às do PIM. Essa semelhança é evidenciada pelo alto coeficiente de Pearson entre os dois métodos (r >0,962). As análises da forma e homogeneidade dos poros, bem como a porosidade aparente, foram melhores determinadas por AM. Porém, quando comparada com o método PIM, divergências quanto à distribuição de tamanho de poros foram observadas. Isso é evidenciado pelo baixo coeficiente de Pearson (r <0,048). Pode-se assim concluir que métodos não convencionais na determinação da porosidade ( 1 H-RMN -CPMG e AM) podem ser utilizados alternativamente aos convencionais (PIM e MA) na caracterização de materiais macroporosos.Palavras-chave: porosimetria, ressonância magnética, intrusão de mercúrio, análise de micrografias. ABSTRACTMacroporous ceramics of Al 2 O 3 are being studied due their diverse applications (biomaterials, anode for solid oxide fuel cells, etc.). The pore distribution, size and interconnection are important parameters that can determine physical and mechanical characteristics of these materials. The aim of this study was analyze and compare different methods of porosimetry. For this, we used the mercury intrusion porosimetry (PIM), Archimedes method (MA), micrographic analysis (AM) and nuclear magnetic resonance with CPMG radiofrequency pulses ( 1 H-RMN -CPMG). Samples of macroporous Al 2 O 3 were obtained by the gelcasting method modified by incorporation of polyethylene spheres at different amounts. The results of these porosimetry methods were treated mathematically, and then the Pearson correlation between the pore size distributions were analyzed. The main advantage of the MA was the simplicity to obtain the apparent porosity, although this method did not provide the pore size distribution. The pore size distribution obtained by 1 H-RMN -CPMG was similar to those obtained by PIM. T...

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“…Various porous substrates have been used for depositing thin-film MEA. Anodized aluminum oxide (AAO) (8)(9)(10) or a nano-porous Ni layer (11)(12)(13) were used as a substrate and they have shown poor performance and stability. The cell with MEA coated on bi-layer of nano-porous Ni and micro-porous STS showed a reasonable stability, however, poor performance (14).…”

Section: Introductionmentioning

confidence: 99%

Micro-SOFC with High Performance and Fast Thermal-Cycling Ability

et al. 2015

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Miniaturized solid-oxide fuel cells (micro-SOFCs) have received growing attention for use in portable devices. Conventional design of micro-SOFC has adopted a freestanding membrane supported by Si substate and used pure metal electrode which has shown poor thermomechanical-stability. In this study, we have developed a new design of micro-SOFC with porous stainless-steel (STS) as a substrate to support a thin-film membrane electrode assembly (MEA) to achieve thermally-robust cell. A composite of nanoporous (La,Sr)(Ti,Ni)O 3 conductor and electrolyte is applied as a contact layer between the macro-porous STS and the thin-film MEA. Excellent electrochemical performance and thermal cycling ability at or below 550 o C for this novel cell are demonstrated.

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Open-circuit voltage of ceria-based thin film SOFC supported on nano-porous alumina

Cited by 50 publications

References 24 publications

High‐Temperature Electrical Conductivity Measurements on Nanostructured Yttria‐Doped Ceria Thin Films in Ozone

High‐Temperature Electrical Conductivity Measurements on Nanostructured Yttria‐Doped Ceria Thin Films in Ozone

Análise comparativa entre diferentes ensaios porosimétricos em alumina macroporosa

Micro-SOFC with High Performance and Fast Thermal-Cycling Ability

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