• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.5
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• pp.384-393
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• 1998

A mixed powder of electrolyte and matrix support materials with a proper proportion was used for the fabrication of an electrolyte matrix sheet. The purpose of this study is to reduce the large change in MCFC cell thickness occurring in the initial start-up period when separate sheets of electrolyte and support are used. A focus was put on how small the carbonate particles could be made. The particle size of the carbonate powder was controlled by ball milling and the distribution was measured using a particle size analyser. The thickness change was reduced to 20% by this approach, which could be compared to 27% observed in a conventional cell. The thickness changes of electrolyte matrix have linear relation sizes of carbonate powders.

• Journal of the Korean Ceramic Society
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• v.47 no.2
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• pp.195-198
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• 2010

It has been considered to apply GDC ($Gd_{0.1}Ce_{0.9}O_{1-X}$) for low-temperature SOFC electrolytes because it has higher ionic conductivity than YSZ at low temperature. However, open circuit voltage with using GDC ($Gd_{0.1}Ce_{0.9}O_{1-X}$) electrolyte in SOFCs, becomes lower than using YSZ (8 mol% Yttria stabilized Zirconia) electrolyte because GDC has electronic conductivity. In this work, the effect of changing GDC electrolyte thickness on the open circuit voltage has been investigated. Ni-GDC anode-supported unit cells were fabricated as follows. Mixed NiO-GDC powders were pressed and pre-sintered at $1200^{\circ}C$. And then, GDC electrolyte material was dip-coated on the anode and sintered at $1400^{\circ}C$. Finally the LSCF-GDC cathode material was screen-printed on the electrolyte and sintered at $1000^{\circ}C$. Electrolyte thickness was controlled by the number of dip-coating times. Open circuit voltage was measured depending on electrolyte thickness at $650^{\circ}C$ and found that the thicker GDC electrolyte was, the better OCV was.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.4
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• pp.225-230
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• 2016

Effect of electrolyte composition and concentration on PEO coating layer were investigated. Mg alloy, Surface of AZ31 and AZ91 were oxidized using PEO with different electrolyte system, Na-P and Na-Si. and applied voltage and concentration. We measured thickness, roughness, X-ray crystallographic analysis and breakdown voltage of the oxidized layer. When increasing concentration of electrolyte, the thickness of oxide layer also increased too. And roughness also increased as concentration of electrolyte increasing. Breakdown voltage of coated layer showed same behavior, the voltage goes high as increasing thickness of coating layer, as increasing concentration of electrolyte, and increasing applied voltage of PEO. $Mg_2SiO_4$ phase were observed as well as MgO.

• Proceedings of the Safety Management and Science Conference
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• 2003.11a
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• pp.351-357
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• 2003

The optimum polymer gel electrolyte composition ratio was 23 : 66 : 11 wt% of P(VdF-co-HFP) : PVP =20 : 3), (PC: EC =44 : 22) and TEABF$_4$. And the optimal thickness of polymer gel electrolyte was 50 ${\mu}{\textrm}{m}$. The electrochemical characteristics result of unit cell were 31.41 Fig of specific capacitance, and 3.21$\times$10$^{-3}$ S/cm of ion conductivity. Ion conductivity of polymer gel electrolytes decreased according to added PVP through impedance analysis, and it was higher in 7 wt%, but electrochemical characteristics of unit cell were better in 3 wt% PVP. And for excellent ion conductivity of polymer gel electrolytes, the use of a thin layer electrolyte(20 $\mu\textrm{m}$) was an effective method, but with unit cell application, the best thickness was 50 $\mu\textrm{m}$. Unit cell showed higher capacitance and more stable electrochemical performance when hot pressed between polymer gel electrolyte and electrode. This results from enhancement of the physical contact between the electrode and the polymer gel electrolyte and good accessibility of the liquid electrolyte to the electrode surface.

• Journal of Electrochemical Science and Technology
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• v.14 no.2
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• pp.145-151
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• 2023

Planer-type electrolyte substrates are often utilized for stack manufacturing of electrolyte-supported solid oxide fuel cells (ES-SOFCs) to fulfill necessary requirements such as a high mechanical strength and redox stability. This work did an electrochemical analysis of ES-SOFC with different NiO-YSZ anode thicknesses to find the optimal value for the high performance of the fuel cell. The cell resistivities were constant at anode thickness between 25-58 ㎛, but a thick anode (74 ㎛) caused a high electrode resistivity leading to a dramatic reduction in cell performance. A stability test was performed for 50 hours at 700℃, and the results showed a degradation rate of 0.3% per 1000 h by extrapolated fitting.

• Journal of information and communication convergence engineering
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• v.8 no.4
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• pp.453-456
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• 2010

Tantalum oxide ($Ta_2O_5$) films are of considerable interest for a range of application, including optical waveguide devices, high temperature resistors, and oxygen sensors. In this paper, we establish an anode oxidation process of tantalum thin film. The voltage drop in the electrolyte is affected not in voltage change but in current change. If the voltage drop in the electrolyte is same with cathode oxidation voltage, the current changes logarithmically in proportion to the voltage drop in interface of tantalum oxide and electrolyte. As a result of the measurement on the electrical property of tantalum oxide thin film, when the thickness of the insulator film is $1500{\AA}$, the breakdown voltage is 350volts and dielectric constant is 29.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.525-530
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• 2019

The performance and stability of solid oxide fuel cells (SOFCs) depend on the microstructure of the electrode and electrolyte. In anode, porosity and pore distribution affect the active site and fuel gas transfer. In an electrolyte, density and thickness determine the ohmic resistance. To optimizing these conditions, using costly method cannot be a suitable research plan for aiming at commercialization. To solve these drawbacks, we made high performance unit cells with low cost and highly efficient ceramic processes. We selected the NiO-YSZ cermet that is a commercial anode material and used facile methods like die pressing and dip coating process. The porosity of anode was controlled by the amount of carbon black (CB) pore former from 10 wt% to 20 wt% and final sintering temperature from $1350^{\circ}C$ to $1450^{\circ}C$. To achieve a dense thin film electrolyte, the thickness and microstructure of electrolyte were controlled by changing the YSZ loading (vol%) of the slurry from 1 vol% to 5 vol. From results, we achieved the 40% porosity that is well known as an optimum value in Ni-YSZ anode, by adding 15wt% of CB and sintering at $1350^{\circ}C$. YSZ electrolyte thickness was controllable from $2{\mu}m$ to $28{\mu}m$ and dense microstructure is formed at 3vol% of YSZ loading via dip coating process. Finally, a unit cell composed of Ni-YSZ anode with 40% porosity, YSZ electrolyte with a $22{\mu}m$ thickness and LSM-YSZ cathode had a maximum power density of $1.426Wcm^{-2}$ at $800^{\circ}C$.

• International Journal of Safety
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• v.10 no.1
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• pp.1-4
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• 2011

The fuel cell is one of the green energy receiving a lot of attention. Among the fuel cells, it is generally referred to SOFC(solid oxide fuel cell) which is made up composites of a solid. SOFC has excellent merits in the side of environment and energy. However because of the high operating temperature, it has economic loss by the using of expensive materials and problems of structural instability by thermal stresses. Therefore, this study aims to the effect of analysis by the FEMLAB. The results have deformations and the maximum stresses from the variation of the thickness of vulnerability spots. The deformation shows expansion as 0.82% and the stress ${\sigma}_{xx}$ is 392MPa in electrolyte and -56.31MPa in anode. When increasing or decreasing the thickness to 50% of the reference thickness about the electrolyte which is vulnerable spots.

• 한국전기화학회:학술대회논문집
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• 1998.10a
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• pp.54-54
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• 1998

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.13-16
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• 2008

Solid oxide fuel cell(SOFC) is an electrochemical energy conversion system with high efficiency and low-emission of pollution. In order to reduce the operating temperature of SOFC system under $800^{\circ}C$, the thickness reduction of YSZ electrolyte to be as thin as possible, e.g., less than 10 ${\mu}m$ are considered with the microstructure control and optimum design of unit cell. Methods for reducing the thickness of YSZ electrolyte have been investigated in coin cell. Moreover, a large unit cell($8cm{\times}8cm$) for SOFC was fabricated using an anode-supported electrolyte assembly with a thinner electrolyte layer, which was prepared by a tape casting method with a co-sintering technique. we studied the design factors such as active layer, electrolyte thickness, cathode composition, etc,. by the coin type of unit cell ahead of the fabrication process of a large unit cell and also reviewed about the evaluation technique of a large size unit cell such as interconnect design, sealing materials and current collector and so forth. Electrochemical evaluations of the unit cells, including measurements such as power density and impedance, were performed and analyzed. Maximum power density and polarization impedance of coin cell were 0.34W/$cm^2$ and $0.45{\Omega}cm^2$ at $800^{\circ}C$, respectively. However, Maxium power density of a large unit cell($5cm{\times}5cm$) decreased to 0.21W/$cm^2$ at $800^{\circ}C$ due to the increase of ohmic resistance. However, It was found that the potential value of a large unit cell loaded by 0.22A/$cm^2$ showed 0.76V at 100hrs without the degradation of unit cell.