• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.569-570
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• 2012

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.161-165
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• 2007

Recently by the development of the electronic engineering technology various mobile devices are developed. But their operation time need to be extended although capacity of the batteries are limited. We focused our attention to the portable SOFC system. Because SOFC has the high efficiency and a lot of strongness in comparison with other kinds of fuel cells. In addition they can be built as a self/non-reformable system and single/dual chamber system. So We evaluated some types of SOFC theoretically, and compared the results from the fuel and performance efficiency point of view.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1007-1008
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• 2013

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.306-309
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• 2005

One of the most critical issues in sol id oxide fuel cell (SOFC)running on hydrocarbon fuels is the risk of carbon formation from the fuel gas. The simple method to reduce the risk of carbon formation from the reactions is to add steam to the fuel stream, leading to the carbon gasification react ion. However, the addition of steam to fuel is not appropriate for the auxiliary power unit (APU) and potable power generation (PPG) systems due to an increase of complexity and bulkiness. In this regard, many researchers have focused on so-called 'direct methane' operation of SOFC, which works with dry methane without coking. However, coking can be suppressed only by the operation with a high current density, which may be a drawback especially for the APU and PPG systems. The single chamber fuel cell (SC-SOFC) is a novel simplification of the conventional SOFC into which a premixed fuel/air mixture is introduced. It relies on the selectivity of the anode and cathode catalysts to generate a chemical potential gradient across the cell. Moreover it allows compact and seal-free stack design. In this study, we fabricated honeycomb type mixed-gas fuel cell (MGFC) which has advantages of stacking to the axial direction and increasing volume power density. Honeycomb-structured SOFC with four channels was prepared by dry pressing method. Two alternative channels were coated with electrolyte and cathode slurry in order to make cathodic reaction sites. We will discuss that the anode supported honeycomb type cell running on mixed gas condition.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.798-804
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• 2006

Co-planar type single chamber solid oxide fuel cell with patterned electrode on a surface of electrolyte has been fabricated by robo-dispensing method and microfluidic lithography. The cells were composed of NiO-GDC-Pd or NiO-SDC cermet anode, $(La_{0.7}Sr_{0.3})_{0.95}MnO_3$ cathode, and yttria stablized zirconia electrolyte. The cell performance at $900^{\circ}C$ was investigated as a function of electrode geometries, such as anode-to-cathode distance, numbers of electrode pairs. Relationship between OCV and I-V characteristics at the optimized operation condition was also studied by DC source meter under the mixed gas condition of methane, air, and nitrogen. An increase of anode-facing-cathode area leads to lower OCV due to intermixing between product gases of anode and cathode, which in turn decreases the oxygen partial pressure difference.

• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.854-859
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• 2005

Performance of micro scale intermediate temperature solid oxide fuel cell system has been successfully evaluated by computer simulation based on macro modeling. Two systems were studied in this work. The one is designed that the ceria-based electrolyte placed between composite electrodes and the other is designed that electrodes alternately placed on the electrolyte. The injected gas was composed of hydrogen and air. The polarization curve was obtained through a series of calculations for ohmic loss, activation loss and concentration loss. The calculation of each loss was based on the solving of mathematical model of multi physical-phenomena such as ion conduction, fluid dynamics and diffusion and convection by Finite Element Method (FEM). The performance characteristics of SOFC were quantitatively investigated for various structural parameters such as distance between electrodes and thickness of electrolyte.

• Journal of the Korean Ceramic Society
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• v.45 no.4
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• pp.232-237
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• 2008

As the single chamber SOFC(SC-SOFC) showed higher prospect on reducing the operation temperature as well as offering higher design flexibility of SOFCs, lots of concerns have been given to investigate the catalytic activity of perovskite-type oxide in mixed fuel and oxidant conditions. Hence we thoroughly investigated the catalytic property of various perovskite-type oxides such as $La_{0.8}Sr_{0.2}MnO_3(LSM),\;La_{0.6}Sr_{0.4}CoO_3(LSC),\;La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3(LSCF),\;Sm_{0.5}Sr_{0.5}CoO_3(SSC),\;and\;Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}(BSCF)$ under the partial oxidation condition of methane which used to be given for SC-SOFC operation. In this study, powder form of each perovskite oxides whose surface areas were controlled to be equal, were investigated as functions of methane to oxygen ratios and reactor temperature. XRD, BET and SEM were employed to characterize the crystalline phase, surface area and microstructure of prepared powders before and after the catalytic oxidation. According to the gas phase analysis with flow-through type reactor and gas chromatography system, LSC, SSC, and LSCF showed higher catalytic activity at fairly lower temperature around $400^{\circ}C{\sim}450^{\circ}C$ whereas LSM and BSCF could be activated at much higher temperature above $600^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.44 no.10
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• pp.542-547
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• 2007

We have determined an optimal reduction condition for NiO-based anode in single chamber solid oxide fuel cells that involve samaria-doped ceria (SDC) as an electrolyte. Optimal condition should not only induce sufficient reduction of NiO to Ni, but also prevent the reduction of SDC electrolyte in order to achieve high open circuit voltage (OCV) and power output. Thermodynamic consideration allowed us to determine the optimal anode reduction condition as $96%H_2-4%H_2O$ atmosphere at $250^{\circ}C$. This finding was in a good agreement with the experimental verifications by monitoring the conductivities of SDC and NiO under different reducing conditions.