• Journal of the Korean Ceramic Society
• /
• v.43 no.12 s.295
• /
• pp.788-797
• /
• 2006

An anode-supported SOFC single cell having $5{\mu}m$ thin electrolyte was fabricated cost-effectively by tape casting, laminating, and co-filing of anode (NiO-YSZ), cathode (LSM-YSZ), and electrolyte (YSZ) components. The optimal slurry compositions of the green tapes for SOFC components were determined by an analysis of the mean diameter, the slurry viscosity, the tensile strength/strain of the green tapes, and their green microstructures. The single cells with a dense electrolyte and porous electrodes could be co-fired successfully at $1325\sim1350^{\circ}C$ by controlling the contents of pore former and the ratio of coarse YSZ and fine YSZ in the anode and the cathode. The single cell co-fired at $1350^{\circ}C$ showed $100.2mWcm^{-2}$ of maximum power density at $800^{\circ}C$ but it was impossible to apply it to operate at low temperature because of low performance and high ASR, which were attributed to formation of the secondary phases in the cathode and the interface between the electrolyte and the cathode.

• Journal of the Korean Electrochemical Society
• /
• v.8 no.2
• /
• pp.88-93
• /
• 2005

Anode-supported solid oxide fuel cell (SOFC) was investigated to increase the cell power density at intermediate temperature through control of the cathode structure. The anode-supported SOFC cell were fabricated by wet process, in which the electrolyte of $8mol\%\;Y_2O_3-stabilized\;ZrO_2 (YSZ)$ was coated on the surface of anode support of Ni/YSA and then the cathode was coated. The cathode has two- or three- layered structure composed of $(La_{0.85}Sr_{0.15})_{0.9}MnO_{3-x}(LSM),\;LSM/YS$ composite (LY), and $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3{LSCF)$ with different thickness. Their single cells with different cathode structures were characterized by measuring the cell performance and ac impedance in the temperature range of 600 to $800^{\circ}C$ in humidified hydrogen with $3\%$ water and air. The cell with $LY\;9{\mu}m/LSM\;9{\mu}m/LSCF\;17{\mu}m$ showed best performance of $590mW/cm^2$, which was attributed to low polarization resistance due to LY and to low interfacial resistance due to LSCF.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2007.11a
• /
• pp.40.1-40.1
• /
• 2007

• 한국초전도학회:학술대회논문집
• /
• v.12
• /
• pp.72-72
• /
• 2002

• 한국초전도학회:학술대회논문집
• /
• v.9
• /
• pp.95-98
• /
• 1999

The crystalline alignment of Ni substrates textured by RABiTS have a probability distribution in the surface plane. This makes it difficult to obtain a high quality of textures over all the range of a long Ni tape. In order to improve the textures of Ni tape, we have investigated a new method of texturing. We obtained non-cube textured Ni tapes by rolling and annealing a high purity Ni. In these tapes, the [001]-axes were tilted around the rolling direction, and the [100]-axes were parallel to the rolling direction. The average grain size was several cm$^2$. We deposited buffer layer (CeO$^2$/YSZ/CeO$^2$) and YBCO on those tapes. We found out that a YBCO film with grows normal with respect to the surface and this feature is independent of the tilting angles of the Ni [001]-axes.

• Korean Chemical Engineering Research
• /
• v.50 no.4
• /
• pp.749-753
• /
• 2012

In present work, anode support for micro-tubular SOFC was fabricated with outer diameter of 3 mm and characterized with microstructure, mechanical properties and gas permeability. The microstructure of surface and cross section of a porous anode support were analyzed by using SEM (Scanning Electron Microscope) image. The gas permeability and the mechanical strength of anode support was measured and analysed by using differential pressure at the flow rates of 50, 100, 150 cc/min. and using universal testing machine respectively. The unit cell composed of NiO-YSZ, YSZ, YSZ-LSM/LSM/LSCF was fabricated and operated with reaction temperature and fuel flow rate and showed maximum power density of $1095mW/cm^2$ on the condition of $800^{\circ}C$. The performance of single cell for micro-tubular SOFC increased with the increasing the reaction temperature due to the decrement of ohmic resistance of cell by the increment of the ionic conductivity of electrolyte through the evaluation of electrochemical impedance analysis for single cell with reaction temperature.

• Journal of the Korean Ceramic Society
• /
• v.41 no.6
• /
• pp.456-463
• /
• 2004

To enhance the performance of anode-supported SOFC, single cell fabrication procedure was changed for better and resulting power generating characteristics of single cell were investigated. Liquid condensation process was employed for the granulation of NiO/YSZ powder mixture and the produced powder granules were compacted into anode green substrate by uni-axial pressing. YSZ electrolyte was printed on green substrate via screen-printing method and co-fired at 1400$^{\circ}C$ for 3 h. LSM/YSZ composite cathode of which the composition and heat treatment condition was adjusted to minimize the polarization#resistance with AC-impedance spectroscopy, was screen printed. The final single cell size from this multi-step procedure was 5${\times}$5 $\textrm{cm}^2$ and 10${\times}$10 $\textrm{cm}^2$. The maximum power densities of 5${\times}$5 and 10${\times}$10 single cells were about 0.45 W/$\textrm{cm}^2$ and 0.22 W/$\textrm{cm}^2$ at 800$^{\circ}C$, which are two times superior than those from single cells fabricated by the conventional process in previous our work.

• Progress in Superconductivity
• /
• v.2 no.1
• /
• pp.33-38
• /
• 2000

Ni tapes were textured by taking advantage of their secondary recrystallization. The obtained 18cm long tapes had textures of single crystalline qualities with their [001] axes tilted with respect to the surface and their [010] axes parallel to the rolling direction. The reproducibility of this texturing was checked by taking statistics on the crystal orientations of 24 Ni tapes. $YBCO/CeO_2/YSZ/CeO_2$ films grown on the Ni tape had the same crystalline orientations. Magnetic field dependent I-V relations were measured on a 5cm section of the tape. $J_c$ defined by $20{\mu}V/mm$ criterion was $1.5\times10^5A/cm^2$ at 77K under zero field and was reduced by $\sim$50% under the applied magnetic field of 5T.

• Journal of the Korean Ceramic Society
• /
• v.43 no.2 s.285
• /
• pp.85-91
• /
• 2006

Electron Beam Physical Vapor Deposition (EB-PVD) was applied to fabricate a thin film YSZ electrolyte with large area on the porous NiO-YSZ anode substrate. Microstructural and thermal stability of the as-deposited electrolyte film was investigated via SEM and XRD analysis. In order to obtain an optimized YSZ film with high stability, both temperature and surface roughness of substrate were varied. A structurally homogeneous YSZ film with large area of $12\times12\;cm^2$ and high thermal stability up to $900^{\circ}C$ was fabricated at the substrate temperature of $T_s/T_m$ higher than 0.4. The smoother surface was proved to give the better film quality. Precise control of heating and cooling rate of the anode substrate was necessary to obtain a very dense YSZ electrolyte with high thermal stability, which affords to survive after post heat treatment for fabrication a cathode layer on it as well as after long time operation of solid oxide fuel cell at high temperature.

• Transactions of the Korean hydrogen and new energy society
• /
• v.21 no.1
• /
• pp.50-57
• /
• 2010

Stepwise production of syn-gas and hydrogen from methane on ferrite based media added with yttria-stabilized zirconia (YSZ) was carried out using a fixed bed infrared reactor. In this study, all M-ferrite (M=Co, Cu, Mn and Ni) media were prepared by co-precipitation method, and there the YSZ was added as a binder to improve thermal stability, reactivity, and resistance against carbon deposition. Most of the ferrite media containing YSZ showed the good redox property for temperature programmed reduction/oxidation (TPR/O) tests. Notably, the Cu-substituted ferrite medium with YSZ showed the great resistance against carbon deposition as well as the good reactivity for the stepwise production of syngas and hydrogen. Furthermore, it also showed the good durability without significant deactivation during five repeated cyclic tests.