Sputter deposition of yttria-stabilized zirconia and silver cermet electrodes for SOFC applications

Wang, L. S.; Thiele, E.; Barnett, Scott A.

doi:10.1016/0167-2738(92)90114-5

Cited by 37 publications

(18 citation statements)

References 11 publications

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“…We will therefore approach the problem of a SOFC operating at reduced temperature by preparing thin film electrolyte as well as thin film cathodes or anodes. Previous studies have shown that it is possible to prepare a thin film electrolyte by various sputtering processes [1,2,3,4,5,6,7,8]. We have decided to now investigate the preparation of electrodes by thin film processes and in particular the cathode, where losses at intermediate temperature are higher.…”

Section: Introductionmentioning

confidence: 98%

Preparation of cathodes for thin film SOFCs

Charpentier

Fragnaud

Schleich

et al. 1997

Ionics

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Abstract. SOFCs are expected to become competitive devices for electrical power generation, but successful application is dependent on decreasing working temperature from 1000 to 800 ~ without detrimental effects on resistance and on electrode processes. This requires a reduction of the stabilized zirconia electrolyte thickness and an optimization of the electrodes, especially the cathode, where losses are higher. Strontium doped lanthanum manganites are the most common materials tested as cathodes for SOFCs working at high temperature (1000 ~ This cathode material presents high electronic and oxygen-ion conductivities, a thermal expansion coefficient compatible with stabilized zirconia and good catalytic activity.For thin film SOFC devices working at intermediate temperatures (less than 800~ we have studied the optimization of this type of cathode. Strontium doped lanthanum manganite has been deposited on yttria stabilized zirconia electrolyte substrates by spray-pyrolysis and by RF sputtering. The electrode performances depend strongly on cathode microstructure, influenced by processing conditions. With spray-pyrolysis processes, large porosity is expected. This is important for the supply of oxygen, via O2 molecules through the pores to the triple phase boundaries, where the gas, the cathode and the electrolyte are in contact and where oxygen reduction may occur. However, large porosity can have a nefaste effect on electronic conductivity. With RF sputtering, denser films with higher electronic conductivity are obtained. But, in that case, the supply of oxygen occurs via adsorbed O-atoms in a diffusion process through the cathode to the electrolyte. Spraypyrolysis and RF sputtering have been compared relative to electrode properties.

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Section: Introductionmentioning

confidence: 98%

Preparation of cathodes for thin film SOFCs

Charpentier

Fragnaud

Schleich

et al. 1997

Ionics

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“…suggested and later demonstrated that capping layers could largely suppress the evaporation of Ag. [20][21][22][23] To take advantage of the triple phase boundary extension seen in composite electrodes, Ag-YSZ cermets were presented. 24,25 It has been found within these cermets, that the length of the oxygen diffusion paths through the Ag was the limiting factor in electrodes with high Ag content.…”

Section: Alternative Electrodesmentioning

confidence: 99%

Nanostructured Solid Oxide Fuel Cell Electrodes

2007

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The ability of Solid Oxide Fuel Cells (SOFC) to directly and efficiently convert the chemical energy in hydrocarbon fuels to electricity places the technology in a unique and exciting position to play a significant role in the clean energy revolution. In order to make SOFC technology cost competitive with existing technologies, the operating temperatures have been decreased to the range where costly ceramic components may be substituted with inexpensive metal components within the cell and stack design.However, a number of issues have arisen due to this decrease in temperature: decreased electrolyte ionic conductivity, cathode reaction rate limitations, and a decrease in anode contaminant tolerance.While the decrease in electrolyte ionic conductivities has been countered by decreasing the electrolyte thickness, the electrode limitations have remained a more difficult problem. Nanostructuring SOFC electrodes addresses the major electrode issues.The infiltration method used in this dissertation to produce nanostructure SOFC 2 electrodes creates a connected network of nanoparticles; since the method allows for the incorporation of the nanoparticles after electrode backbone formation, previously incompatible advanced electrocatalysts can be infiltrated providing electronic conductivity and electrocatalysis within well-formed electrolyte backbones. Furthermore, the method is used to significantly enhance the conventional electrode design by adding secondary electrocatalysts. Performance enhancement and improved anode contamination tolerance are demonstrated in each of the electrodes. Additionally, cell processing and the infiltration method developed in conjunction with this dissertation are reviewed.

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“…Barnett and coworkers [39][40][41][42] suggested and later demonstrated that capping layers could largely suppress the evaporation of Ag and Ag-YSZ cermets were synthesised and tested [43,44]. Trimm [33] suggested that doping Ni with small quantities of other metals, like Ag, can minimise the formation of carbon and as Sholklapper et al [35] demonstrated recently, Ag-LSM electrodes displayed stable electrocatalytic behaviour when used as cathodes in SOFCs.…”

Section: Introductionmentioning

confidence: 98%

Thermogravimetric and Electrocatalytic Study of Carbon Deposition of Ag‐doped Ni/YSZ Electrodes under Internal CH₄ Steam Reforming Conditions

et al. 2009

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The effect of Ag addition on Ni/YSZ Carbon tolerance was studied by means of thermogravimetric, catalytic and electrocatalytic experiments. Ni/YSZ activity towards C deposition can be significantly decreased by adding 1 to 5 at.‐% (atomic ratio) Ag with respect to Ni. It was found that the activation energy of CH4 dissociation was increased from 61 kJ mol–1 on Ni/YSZ to 137 kJ mol–1 on Ni(5Ag)/YSZ. The electrode was significantly improved with regard to its C tolerance, even at a methane to water ratio as high as 4.35, at temperatures ranging between 923–1,023 K. At higher temperature most probably due to Ag evaporation from Ag‐doped Ni/YSZ surface, a severe anode catalytic and electrocatalytic activity degradation was observed.

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Sputter deposition of yttria-stabilized zirconia and silver cermet electrodes for SOFC applications

Cited by 37 publications

References 11 publications

Preparation of cathodes for thin film SOFCs

Preparation of cathodes for thin film SOFCs

Nanostructured Solid Oxide Fuel Cell Electrodes

Thermogravimetric and Electrocatalytic Study of Carbon Deposition of Ag‐doped Ni/YSZ Electrodes under Internal CH₄ Steam Reforming Conditions

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Sputter deposition of yttria-stabilized zirconia and silver cermet electrodes for SOFC applications

Cited by 37 publications

References 11 publications

Preparation of cathodes for thin film SOFCs

Preparation of cathodes for thin film SOFCs

Nanostructured Solid Oxide Fuel Cell Electrodes

Thermogravimetric and Electrocatalytic Study of Carbon Deposition of Ag‐doped Ni/YSZ Electrodes under Internal CH4 Steam Reforming Conditions

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Product

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Thermogravimetric and Electrocatalytic Study of Carbon Deposition of Ag‐doped Ni/YSZ Electrodes under Internal CH₄ Steam Reforming Conditions