• Title/Summary/Keyword: SOFC anode

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Effect of the Pore Structure on the Anodic Property of SOFC (SOFC 음극의 기공구조가 음극특성에 미치는 영향)

  • 허장원;이동석;이종호;김재동;김주선;이해원;문주호
    • Journal of the Korean Ceramic Society
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    • v.39 no.1
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    • pp.86-91
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    • 2002
  • Solid Oxide Fuel Cells (SOFC) are of great interest of next generation energy conversion system due to their high energy efficiency and environmental friendliness. The basic SOFC unit consists of anode, cathode and solid electrolyte. Among these components, anode plays the most important role for the oxidation of fuel to generate electricity and also behaves as a substrate of the whole cell. It is normally requested that the anode materials should have the high electrical conductivity and gas permeability to reduce the polarization loss of the cell. In this study, the effect of pore former on the microstructure of anode substrate was investigated and thus on the electrical conductivity and the gas permeability. According to the results, microstructure and electrical conductivity of anode substrate were greatly influenced by the shape of pore former and especially by the anisotrpy of the pore former. The use of anisotropic pore former is supposed to deteriorate the cell performance by which the electrical conduction path is disconnected but also the effective gas diffusion path for the fuel is reduced.

Mass Transfer Analysis of Metal-Supported and Anode-Supported Solid Oxide Fuel Cells (금속지지체형 고체산화물연료전지와 연료극지지체형 고체산화물연료전지의 물질전달 특성분석)

  • Park, Joon-Guen;Kim, Sun-Young;Bae, Joong-Myeon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.3
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    • pp.317-324
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    • 2010
  • Metal-supported solid oxide fuel cells (SOFCs) have been developed to commercialize SOFCs. This new type of SOFC has high mechanical strength, but its mass transfer rate may be low due to the presence of a contact layer. In this study, the mass transfer characteristics of an anode-supported SOFC and a metal-supported SOFC are studied by performing numerical simulation. Governing equations, electrochemical reactions, and ceramic physical-property models are determined simultaneously; molecular diffusion and Knudsen diffusion are considered in mass transport analysis of porous media. The experimental results are compared with simulation data to validate the results of numerical simulation. The average current density of the metal-supported SOFC is 23% lower than that of the anode-supported SOFC. However, because of the presence of the contact layer, the metal-supported SOFC has a more uniform distribution than the anode-supported SOFC.

Ejector Optimization for SOFC Anode Off-Gas Recirculation System (SOFC 산화전극 배기가스 순환 시스템을 위한 이젝터 최적 설계)

  • Jo, Sung Jong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.2
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    • pp.139-148
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    • 2013
  • In this study, an ejector was designed to recirculate the anodic off-gas of SOFC, and a parametric study of the system performance was conducted at various ejector entrainment ratios. Aspen Plus, a chemical engineering program, was used to calculate the operational conditions of the ejector. To minimize the calculation load of the CFD and to ensure the global optimum, a genetic algorithm and Kriging model were used for the optimization. The optimization results showed that the dominant design variables of the sonic ejector are the throat diameter and the first flow nozzle position. The designed ejector has enough flexibility for different operating conditions of a 1-kW SOFC system. When the ejector was applied to the SOFC, it reduced 56% of the steam and 8.4% of the fuel compared to the reference case.

Competitive electrochemical oxidation of reformate gas in SOFCs (고체 산화물 연료전지 음극에서 개질 가스의 경쟁적 전기화학 반응)

  • Kim, Yong-Min;Bae, Joong-Myeon;Bae, Gyu-Jong;Kim, Jung-Hyun;Lee, Chang-Bo
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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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.

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Correlatin between the Microstructure and the Electrical Conductivity of SOFC anode, Ni-YSZ : I. Microstructure Analysis (SOFC 음극용 Ni-YSZ 복합체의 미세구조와 전기적 물성간의 상관관계 : I. 미세구조 분석)

  • Moon, Hwan;Lee, Hae-Weon;Lee, Jong-Ho;Yoon, Ki-Hyun
    • Journal of the Korean Ceramic Society
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    • v.37 no.5
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    • pp.479-490
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    • 2000
  • The microstructure of Ni-YSZ composite as an anode of SOFC was investigated as a function of Ni content(10-70 vol%) in order to examine the correlation between microstructural-and electrical property. Image analysis based on quantitative microscopy theory was performed to quantify the microstructural property. We could get the informations about the size and distribution, contiguity and interfacial area of each phase or between the phases from the image analysis. According to the image analysis, contiguity between the same phae was mainly dependent on the amount of the phase while the contiguity between different phases was additionally influenced by the microstructural changes, especailly by the coarsening of the Ni phase. The whole length of pores perimeter was increased as Ni content increased, which indicated the overall microstructural evolution was mostly related with the coarsening of Ni phase. Ni-Ni interfacial area was also gradually increased as Ni content increased but controlled by pore phase at low Ni content region and by YSZ phase at intermediate Ni content region. These quantified microstructural properties were used to characterize the electrical properties of Ni-YSZ composite.

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Performance of SOFC According to Thickness of Shell with Ni-YSZ Core-shell (Ni-YSZ Core-shell에서 Shell의 두께에 따른 SOFC의 출력특성)

  • CHOI, BYUNG-HYUN;HONG, SUN-KI;JI, MI-JUNG
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.6
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    • pp.663-668
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    • 2017
  • SOFC anode fabricated core-shell using machano-fusion method using core with submicron size Ni, nano size YSZ for shell. Using prepared core-shell, depending on the thickness of the shell, we studied how the characteristics of sintering and SOFC cell change by sintering the anode. The Ni-YSZ core-shell has a Ni core of 0.5 to $1.2{\mu}m$ over 2 to 7 YSZ of 15 to 20 nm is, and as the high speed mixing time increases, the YSZ number increases and the shell thickness becomes uniform increased. When the fuel electrode is manufactured with core-shell, it has superior sintering property, has grain of uniform size compared with the one synthesized by general mixing, the falling path is short, the conductors (electrons and ions) connection is excellent, the electrical conductivity has become excellent. The thicker the shell, the lower the electrical conductivity. When the thickness of shell ranged from 46 to 139 nm and 61 to 81 nm, the performance was the highest and the ASR was the smallest.