• Title/Summary/Keyword: SOFC anode

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Effect of Cathode Porosity of Mixed Conducting (La0.6Sr0.4Co0.2Fe0.8O3) on the Power Generating Characteristics of Anode Supported SOFCs (혼합전도체 LSCF(La0.6Sr0.4Co0.2Fe0.8O3) 양극의 기공률에 따른 음극지지형 단전지의 출력특성 평가)

  • Yun, Joong-Cheul;Kim, Woo-Sik;Kim, Hyoungchul;Lee, Jong-Ho;Kim, Joosun;Lee, Hae-Weon;Kim, Byong-Ho
    • Journal of the Korean Ceramic Society
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    • v.42 no.4
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    • pp.269-275
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    • 2005
  • We analyzed the unit cell performance against the cathode porosity, which is supposed to be closely related with active sites for the cathode reaction. In order to fabricate the unit cells with different porosity in the cathode layer we changed the mixing ratio of fine and coarse LSCF cathode powders. The final porosity of each cathode layer was 14, 23, 27, $39\%$ respectively. According to the electrochemical analysis of unit cell performance via DC current interruption and AC impedance method, the electrodic polarization resistance was diminished as the cathode porosity increased. The decrease of polarization resistance was attributed due to the increase of active reaction sites and the enhancement of overall unit cell performance could be explained in the same line.

Synthesis and Characterization of La0.75Sr0.25FeO3 Used as Cathode Materials for Solid Oxide Fuel Cell by GNP Method (GNP법을 이용한 고체산화물 연료전지의 공기극용 La0.75Sr0.25FeO3의 제조 및 특성)

  • Park, Ju-Hyun;Son, Hui-Jeong;Lim, Tak-Hyoung;Lee, Seung-Bok;Yun, Ki-Seok;Yoon, Soon-Gil;Shin, Dong-Ryul;Song, Rak-Hyun
    • Journal of the Korean Electrochemical Society
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    • v.10 no.1
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    • pp.7-13
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    • 2007
  • We synthesized and investigated $La_{0.75}Sr_{0.25}FeO_3$ by Glycine Nitrate Process(GNP) method used as cathode materials for SOFC(solid oxide fuel cell). Optimized amount of glycine is 3.17 mol. ICP elemental composition analysis indicated that the stoichiometry of the synthesized powders have nearly nominal values. SEM images and XRD patterns reveal that the synthesized powder has uniform size distribution and high degree of crystallinity. The sample powders were isostatically pressed to form a pellet. The green body was sintered at $1200^{\circ}C$ and the relative density of the sintered specimens were measured by Archimedes mettled. We measured electrochemical performance of LSF by AC impedance spectroscopy. Resistance of LSF shows lower value than that of LSM throughout all temperature region. The anode-supported solid oxide fuel cell showed a performance of $342mW/cm^2(0.7V,\;488mA/cm^2)$ at $750^{\circ}C$. The electrochemical characteristics of the single cell were examined by at impedance method.

Preparation of Al-doped NiO via Solvothermal Synthesis and its Crystal Structural and Electrical Properties (용매열 합성법을 통하여 알루미늄을 도핑한 니켈옥사이드의 제조와 그 결정구조적, 전기적 특성)

  • Hong, Sun-Ki;Ji, Mi-Jung;Lee, Min-Jin;Jung, Sung-Hun;Seol, Kwang-Hee;Choi, Byung-Hyun
    • Korean Journal of Materials Research
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    • v.22 no.11
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    • pp.631-635
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    • 2012
  • Nickel oxide was doped with a wide range of concentrations (mol%) of Aluminum (Al) by solvothermal synthesis; single-phased nano powder of nickel oxide was generated after calcination at$900^{\circ}C$. When the concentration of Al dopant was increased, the reduced intensity was confirmed through XRD analysis. Lattice parameters of the synthesized NiO powder were decreased after treatment of the dopant; parameters were increased when the concentration of Al was over the doping limit (5 mol% Al). The binding energy of $Ni^{2+}$ was chemically shifted to $Ni^{3+}$ by doping $Al^{3+}$ ion, as confirmed by the XPS analysis. The tilted structure of the synthesized NiO with 5 mol% Al dopant and the polycrystalline structure of the $Ni_{0.75}Al_{0.25}O$ were observed by HR-TEM analysis. The electrical conductivity of the newly synthesized NiO was highly improved by Al doping in the conductivity test. The electrical conductivity values of the commercial NiO and the synthesized NiO with 5 mol% Al dopant ($Ni_{0.95}Al_{0.05}O$) were 1,400 s/cm and 2,230 s/cm at $750^{\circ}C$, respectively. However, the electrical conductivity of the synthesized NiO with 10 mol% Al dopant ($Ni_{0.9}Al_{0.1}O$) decreased due to the scattering of free-electrons caused by the large number of impurity atoms; the electrical conductivity of $Ni_{0.9}Al_{0.1}O$ was 545 s/cm at $750^{\circ}C$.

Influence of Gd0.1Ce0.9O2-δ Interlayer between La0.6Sr0.4Co0.2Fe0.8O3-δ Cathode and Sc-doped Zirconia Electrolyte on the Electrochemical Performance of Solid Oxide Fuel Cells (La0.6Sr0.4Co0.2Fe0.8O3-δ 공기극과 Sc이 도핑된 지르코니아 전해질 사이에 삽입한 Gd0.1Ce0.9O2-δ 중간층이 고체산화물 연료전지의 전기화학적 성능에 미치는 영향)

  • Lim, Jinhyuk;Jung, Hwa Young;Jung, Hun-Gi;Ji, Ho-Il;Lee, Jong-Ho
    • Ceramist
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    • v.21 no.4
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    • pp.378-387
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    • 2018
  • The optimal fabrication conditions for $Gd_{0.1}Ce_{0.9}O_{2-{\delta}}$(GDC) buffer layer and $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LSCF) cathode on 1mol% $CeO_2-10mol%\;Sc_2O_3$ stabilized $ZrO_2$ (CeScSZ) electrolyte were investigated for application of IT-SOFCs. GDC buffer layer was used in order to prevent undesired chemical reactions between LSCF and CeScSZ. These experiments were carried out with $5{\times}5cm^2$ anode supported unit cells to investigate the tendencies of electrochemical performance, Microstructure development and interface reaction between LSCF/GDC/CeScSZ along with the variations of GDC buffer layer thickness, sintering temperatures of GDC and LSCF were checked, respectively. Electrochemical performance was analyzed by DC current-voltage measurement and AC impedance spectroscopy. Microstructure and interface reaction were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Although the interfacial reaction between these materials could not be perfectly inhibited, We found that the cell, in which $6{\mu}m$ GDC interlayer sintered at $1200^{\circ}C$ and LSCF sintered at $1000^{\circ}C$ were applied, showed good interfacial adhesions and effective suppression of Sr, thereby resulting in fairly good performance with power density of $0.71W/cm^2$ at $800^{\circ}C$ and 0.7V.