• Journal of Electrochemical Science and Technology
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• 제14권2호
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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.

• 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.

• Journal of Advanced Marine Engineering and Technology
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• 제35권5호
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• pp.590-599
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• 2011

연료전지시스템의 고효율화를 목적으로 수소가 가진 화학적 에너지를 최대한 전력화하기 위하여 연료전지에서 발생하는 폐열을 적극 활용할 필요가 있다. 이런 목적에 폐열을 이용하는 증기터빈과 연료 전지를 결합시킨 SOFC/ST 하이브리드시스템이 적합하다. 본 논문은 SOFC/ST 하이브리드시스템에 대한 셀의 작동온도와 전류밀도, 연소기 출구 온도, 보일러 출구 가스온도가 시스템의 성능에 미치는 영향 등을 시뮬레이션을 통하여 검토한 것으로 증기터빈의 일정 조건에서는 연료전지 스택에서 다량의 폐열이 발생하는 경우가, 연료전지의 일정 조건에서는 연소기에 추가적 연료 공급을 억제하는 경우에서 하이브리드시스템의 효율이 증가됨을 확인하였다.

• 한국수소및신에너지학회논문집
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• 제31권5호
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• pp.436-443
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• 2020

The performance prediction model of a solid oxide fuel cell stack has been developed using deep neural network technique, one of the machine learning methods. The machine learning has been received much interest in various fields, including energy system mo- deling. Using machine learning technique can save time and cost requried in developing an energy system model being compared to the conventional method, that is a combination of a mathematical modeling and an experimental validation. Results reveal that the mean average percent error, root mean square error, and coefficient of determination (R2) range 1.7515, 0.1342, 0.8597, repectively, in maximum. To improve the predictability of the model, the pre-processing is effective and interpolative machine learning and application is more accurate than the extrapolative cases.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.5-8
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• 2008

SOFC (Solid oxide fuel cell) has an advantage in the term of fuel flexibility, comparing with other kinds of fuel cells. In SOFC and fuel reformer cooperation system, the reformate gas with the various $H_2$/CO ratios is delivered into the anode of SOFC. In this situation, electrochemical oxidation reactions of the reformate gas in the anode are complex and competitive. In this paper, the effects of the composition of $H_2$ and CO on the overall electrochemical oxidation at Ni-YSZ anode are studied by testing the open circuit voltage (OCV) and current-voltage characteristics of single cells.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.2969-2973
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• 2014

A new process to fabricate a composite LSCF-Ag cathode material for SOFCs by electron beam (e-beam) irradiation process has been suggested for operation under intermediate temperature range of $600-700^{\circ}C$. A composite LSCF-Ag cathode with uniformly coated Ag nanoparticles on the surface of the LSCF material was prepared by a facile e-beam irradiation method at room temperature. The morphology of the composite LSCF-Ag material was analyzed using a TEM, FE-SEM, and EDS. The prepared composite LSCF-Ag material can play a significant role in increasing the electro-catalytic activities and reducing the operating temperature of SOFCs. The performance of a tubular single cell prepared using the composite LSCF-Ag cathode, YSZ electrolyte and a Ni/YSZ anode was evaluated at reduced operating temperature of $600-700^{\circ}C$. The micro-structure and chemical composition of the single cell were investigated using a FE-SEM and EDS.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1664-1669
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• 2004

Design analysis of the solid oxide fuel cell and gas turbine combined power system is performed considering different methods for preheating cell inlet air. The purpose of air preheating is to keep the temperature difference between cell inlet and outlet within a practical design range. Three different methods are considered such as a burner in front of the cell, a preheater in front of the cell and recirculation of the cathode exit gas. Analyses are carried out for two maximum cell temperature differences. The greater temperature difference ensures higher efficiency. The cathode exit gas recirculation exhibits better performance than other methods.

• 마이크로전자및패키징학회지
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• 제22권4호
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• pp.77-82
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• 2015

To increase the performance of solid oxide fuel cell operating at intermediate temperature ($600^{\circ}C{\sim}800^{\circ}C$), $Sm_{0.2}Ce_{0.8}O_2$ (SDC) thin layer was applied to the $La_{0.8}Sr_{0.2}Mn_{0.8}Cu_{0.2}O_3$ (LSMCu) cathode by sol-gel coating method. The SDC was employed as a diffusion barrier layer on the yttria-stabilized zirconia(YSZ) to prevent the interlayer by-product formation of $SrZrO_3$ or $La_2Zr_2O_7$. The by-products were hardly formed at the electrolyte-cathode interlayer resulting to reduce the cathode polarization resistance. Moreover, SDC thin film was coated on the cathode pore wall surface to extend the triple phase boundary (TPB) area.

• 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.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.133-136
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• 2007

Perovskite-structured samarium strontium cobaltite (SSC), which is mixed ionic electronic conductor (MIEC), is considered as a promising cathode material for intermediate temperature-operating solid oxide fuel cell (SOFC) due to its high electrocatalytic property. Cathode material containing cobalt (Co) is unstable at high temperature and has a relatively high thermal expansion property. In this paper, Sm-Sr-(Co,Fe,Ni)-O system with perovskite and spinel structures was investigated in terms of electrochemical property and thermal expansion property, respectively. Area specific resistance (ASR) was measured by ac impedance spectroscopy to investigate the electrochemical property of cathode, and thermal expansion coefficient (TEC) was measured by using dilatometer. Micro structure of cathode was observed by scanning electron microscopy. Perovskite-structured $Sm_{0.5}Sr_{0.5}CoO_{3-\delta}$ showed the ASR of $0.87{\Omega}/cm^{2}$, and $Sm_{0.5}Sr_{0.5}NiO_{3-\delta}$, which actually has a spinel structure, showed the lowest TEC value of $13.3{\times}10^{-6}/K$.