• 한국재료학회지
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• 제14권5호
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• pp.368-373
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• 2004

To improve the conventional cathode-supported tubular solid oxide fuel cell (SOFC) from the viewpoint of low cell power density, expensive fabrication process and high operation temperature, the anode-supported tubular solid oxide fuel cell was investigated. The anode tube of Ni-8mol% $Y_2$O$_3$-stabilized $ZrO_2$ (8YSZ) was manufactured by extrusion process, and, the electrolyte of 8YSZ and the multi-layered cathode of $LaSrMnO_3$(LSM)ILSM-YSZ composite/$LaSrCoFeO_3$ were coated on the surface of the anode tube by slurry dip coating process, subsequently. Their cell performances were examined under gases of humidified hydrogen with 3% water and air. In the thermal cycle condition of heating and cooling rates with $3.33^{\circ}C$/min, the anode-supported tubular cell showed an excellent resistance as compared with the electrolyte-supported planar cell. The optimum hydrogen flow rate was evaluated and the air preheating increased the cell performance due to the increased gas temperature inside the cell. In long-term stability test, the single cell indicated a stable performance of 300 mA/$\textrm{cm}^2$ at 0.85 V for 255 hr.

• Journal of Advanced Marine Engineering and Technology
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• 제39권7호
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• pp.765-772
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• 2015

본 연구는 SOFC/GT(Solid Oxide Fuel Cell/Gas Turbine)시스템의 SOFC 스택으로 공급되는 공기, 메탄 및 물의 유량변화에 따른 SOFC/GT시스템의 온도, 스택 출력 및 시스템 효율의 특성에 관하여 조사하였다. 이 때 SOFC 스택의 애노드 및 캐소드로 공급되는 가스 온도는 외부 열원의 추가 없이 시스템에서 배출되는 배기가스를 활용하여 일정하게 유지하였다. 그 결과 본 연구의 범위 내에서 외부 열원의 추가 없이 SOFC/GT시스템의 배기가스를 활용하여 SOFC 스택으로 공급되는 애노드 및 캐소드 가스 공급온도를 1000(K)로 일정하게 유지하는 것이 가능하였다. 시스템 효율은 공급 공기 유량은 많을수록, 공급 메탄 유량은 적을수록 높아짐을 알 수 있었고, 터빈으로 공급되는 배기 가스의 유량이 시스템 효율에 큰 영향을 미침을 알 수 있었다. 또한, SOFC/GT시스템의 운전 조건에 따라서 SOFC 스택 효율은 51~57%, 시스템 효율은 57~73%의 값을 얻을 수 있었다.

• 한국세라믹학회지
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• 제51권4호
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• pp.289-294
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• 2014

The stability of a solid oxide fuel cell (SOFC) stack is strongly dependent on the magnitude and profile of the internal chemical potential of the solid electrolyte. If the internal partial pressure is too high, the electrolyte can be delaminated from the electrodes. The formation of high internal pressure is attributed to a negative cell voltage, and this phenomenon can occur in a bad cell (with higher resistance) in a stack. This fact implies that the internal chemical potential plays an important role in determining the lifetime of a stack. In the present work, we fabricate planar type anode-supported cells ($25cm^2$) with a bi-layer electrolyte (with locally increased electronic conduction at the anode side) to prevent high internal pressure, and we test the fabricated cells under a negative voltage condition. The results indicate that the addition of electronic conduction in the electrolyte can effectively depress internal pressure and improve the cell stability.

• 한국수소및신에너지학회논문집
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• 제20권5호
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• pp.384-389
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• 2009

KEPRI (Korea Electric Power Research Institute) has studied planar type solid oxide fuel cell (SOFC) stacks using anode-supported cells and kW class co-generation systems for residential power generation. In this work, a 1 kW SOFC system consisted of a hot box part, a cold BOP (balance of plant) part, and a hot water reservoir. The hot box part contained a SOFC stack made up of 48 cells, a fuel reformer, a catalytic combustor, and heat exchangers. Thermal management and insulation system were especially designed for self-sustainable operation in that system. A cold BOP part was composed of blowers, pumps, a water trap, and system control units. When the 1 kW SOFC stack was tested using hydrogen at $750^{\circ}C$, the stack power was about $1.2\;kW_e$ at 30 A and $1.6\;kW_e$ at 50 A. Turning off an electric furnace, the SOFC system was operated using hydrogen and city gas without any external heat source. Under self-sustainable operation conditions, the stack power was about $1.3\;kW_e$ with hydrogen and $1.2\;kW_e$ with city gas respectively. The system also recuperated heat of about $1.1\;kW_{th}$ by making hot water.

• 전기화학회지
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• 제12권2호
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• pp.119-130
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• 2009

본 논문에서는 고체산화물 연료전지의 스택 제조 및 시스템 연구개발의 최근 연구동향을 살펴보았다. 고체산화물 연료전지는 연료의 화학적 에너지를 전기적 에너지로 변환시킬 수 있는 친환경, 고효율의 전기화학장치이다. 고체산화물 연료전지 발전시스템은 응용분야에 따라 중대형 분산발전, 가정용 열병합 발전, 보조전원 및 휴대용 발전 시스템으로 구분할 수 있으며, 10 kW급 이상의 SOFC 발전시스템의 경우 원통형 셀로 구성된 발전시스템이 연구개발의 주를 이루고 있다. 더불어, SOFC 발전시스템 연구개발의 경우 매년 증가하는 세계 전력소비량에 대응하기 위해 발전시장에 진입 가능한 고성능, 장수명의 SOFC 소재 및 발전시스템에 R&D 노력이 집중되고 있다.

• 한국수소및신에너지학회논문집
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• 제29권4호
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• pp.317-323
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• 2018

Solid oxide fuel cell (SOFC) operates at high temperature, therefor has the advantage of higher power generation and using exhaust heat than other fuel cells. In particular, the reforming reaction can be performed inside the SOFC stack to reduce the cooling of the stack and the burden on the reformer reactor. In this study, the reformer structure, operating characteristics, and thermal efficiency were evaluated for the optimization design of a heat exchanger type reformer of a 1 kW SOFC system.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.61-64
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• 2008

$Pr_{0.3}Sr_{0.7}Co_{0.3}Fe_{0.7}O_{3-\delta}$ (PSCF3737) was prepared and characterized as a cathode material for intermediate temperature-operating solid oxide fuel cell (IT-SOFC). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS), and electrical property measurement were carried out to study cathode performance of the material. XPS and EXAFS results proved that oxygen vacancy concentration was decreased and lattice constants of the perovskite structure material were increased by doping Fe up to 70 mol% at B-site of the crystal structure, which also extended the distance between oxygen and neighbor atoms. Thermal expansion coefficient (TEC) of PSCF3737 is smaller than that of $Pr_{0.3}Sr_{0.7}CoO_{3-\delta}$(PSC37) due to lower oxygen vacancy concentration. PSCF3737 showed better cathode performance than PSC37. It might be due good adhesion by a smaller difference of TEC between $Gd_{0.1}Ce_{0.9}O_2$ (CGO91) and electrode. Composite material PSCF3737-CGO91 showed better compatibility of TEC than PSCF3737. However, PSCF3737-CGO91 did not represent higher electrochemical property than PSCF3737 due to decreased reaction sites by CGO91.

• 전기화학회지
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• 제8권2호
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• pp.106-114
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• 2005

This article covers the theoretical ac-impedance models for the analysis of oxygen reduction on the porous cathode electrode f3r solid oxide fuel cell (SOFC). Firstly, ac-impedance models were explained on the basis of the mechanism of oxygen reduction, which were classified into the rate-determining steps; (i) adsorption of oxygen atom on the electrode surface, (ii) diffusion of adsorbed oxygen atom along the electrode surface towards the three-phase (electrode/electrolyte/gas) boundaries, (iii) surface diffusion of adsorbed oxygen atom m ixed with the adsorption reaction of oxygen atom on the electrode surface and (iv) diffusion of oxygen vacancy through the electrode coupled with the charge transfer reaction at the electrode/gas interface. In each section for ac-impedance model, the representative impedance plots and the interpretation of important parameters attributed to the oxygen reduction reaction were explained. Finally, we discussed in detail the applications of the proposed theoretical ac-impedance models to the real electrode of SOFC system.

• E2M - 전기 전자와 첨단 소재
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• 제9권9호
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• pp.949-953
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• 1996

In this paper, the cathode materials of solid oxide fuel cell were fabricated, and the analysis of TG/DTA, XRD, thermal expansion and electric conductivity were investigated. As a result, thermal expansion coefficient of LSM was not quite different from that of electrolyte. And the performance of LSM(x=0.4) was more excellent than the others.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2001년도 연료전지심포지움 2001논문집
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• pp.118-123
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• 2001