• Title, Summary, Keyword: Ceramic composite anode

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Catalytic Effects of Barium Carbonate on the Anodic Performance of Solid Oxide Fuel Cells

  • Yoon, Sung-Eun;Ahn, Jae-Yeong;Park, Jong-Sung
    • Journal of the Korean Ceramic Society
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    • v.52 no.5
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    • pp.350-355
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    • 2015
  • To develop ceramic composite anodes of solid oxide fuel cells without metal catalysts, a small amount of barium carbonate was added to an $(La_{0.8}Sr_{0.2})(Cr_{0.5}Mn_{0.5})O_3(LSCM)$ - YSZ ceramic composite anode and its catalytic effects on the electrode performance were investigated. A barium precursor solution with citric acid was used to synthesize the barium carbonate during ignition, while a barium precursor solution without citric acid was used to create hydrated barium hydroxide. The addition of barium carbonate to the ceramic composite anode caused stable fuel cell performance at 1073 K; this performance was higher than that of a fuel cell with $CeO_2$ catalyst; however, the addition of hydrated barium hydroxide to the ceramic composite anode caused poor stability of the fuel cell performance.

Fabrication of NiO-Y:BaZrO3 Composite Anode for Thin Film-Protonic Ceramic Fuel Cells using Tape-Casting

  • Bae, Kiho;Noh, Ho-Sung;Jang, Dong Young;Kim, Manjin;Kim, Hyun Joong;Hong, Jongsup;Lee, Jong-Ho;Kim, Byung-Kook;Son, Ji-Won;Shim, Joon Hyung
    • Journal of the Korean Ceramic Society
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    • v.52 no.5
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    • pp.320-324
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    • 2015
  • Optimization of the fabrication process of NiO-yttrium doped barium zirconate (BZY) composite anode substrates using tape-casting for high performance thin-film protonic ceramic fuel cells (PCFCs) is investigated. The anode substrate is composed of a tens of microns-thick anode functional layer laminated over a porous anode substrate. The macro-pore structure of the anode support is induced by micron-scale polymethyl methacrylate (PMMA) pore formers. Thermal gravity analysis (TGA) and a dilatometer are used to determine the polymeric additive burn-out and sintering temperatures. Crystallinity and microstructure of the tape-cast NiO-BZY anode are analyzed after the sintering.

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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Anode-supported Type SOFCs based on Novel Low Temperature Ceramic Coating Process

  • Choi, Jong-Jin;Ahn, Cheol-Woo;Kim, Jong-Woo;Ryu, Jungho;Hahn, Byung-Dong;Yoon, Woon-Ha;Park, Dong-Soo
    • Journal of the Korean Ceramic Society
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    • v.52 no.5
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    • pp.338-343
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    • 2015
  • To prevent an interfacial reaction between the anode and the electrolyte layer during the conventional high-temperature co-firing process, an anode-supported type cell with a thin-film electrolyte was fabricated by low-temperature ceramic thick film coating process. Ni-GDC cermet composite was used as the anode material and YSZ was used as the electrolyte material. Open circuit voltage and maximum power density were found to strongly depend on the surface uniformity of the anode functional layer. By optimizing the microstructure of the anode functional layer, the open circuit voltage and maximum powder density of the cell increased to 1.11 V and $1.35W/cm^2$, respectively, at $750^{\circ}C$. When a GDC barrier layer was applied between the YSZ electrolyte and the LSCF cathode, the cell showed good stability, with almost no degradation up to 100 h. Anode-supported type SOFCs with high performance and good stability were fabricated using a coating process.

Characterization and Fabrication of La(Sr)Fe(Co)O3-δ Infiltrated Cathode Support-Type Solid Oxide Fuel Cells (La(Sr)Fe(Co)O3-δ 침지법을 이용한 양극 지지형 SOFC 제조 및 출력 특성)

  • Hwang, Kuk-Jin;Kim, Min Kyu;Kim, Hanbit;Shin, Tae Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.32 no.6
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    • pp.501-506
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    • 2019
  • To overcome the limitations of the conventional Ni anode-supported SOFCs, various types of ceramic anodes have been studied. However, these ceramic anodes are difficult to commercialize because of their low cell performances and difficulty in manufacturing anode-support typed SOFCs. Therefore, in this study, to use these ceramic anodes and take advantage of anode-supported SOFC, which can minimize ohmic loss from the thin electrolyte, we fabricated cathode support-typed SOFC. The cathode-support of LSCF-YSZ was prepared by the acid treatment of conventional Ni-YSZ (Yttria-stabilized Zirconia) anode-support, followed by the infiltration of LSCF to YSZ scaffold. The composite of $La(Sr)Ti(Ni)O_3$ and $Ce(Mn,Fe)O_2$ was used as the ceramic anode. The fabricated cathode-supported button cell showed a relatively low power density of $0.207Wcm^{-2}$ at $850^{\circ}C$; however, it is expected to show better performance through the optimization of the infiltration rate and thickness of LSCF-YSZ cathode-support layer.

Optimum Reduction Condition of SDC-NiO Composite Anode for SDC-based Single Chamber Solid Oxide Fuel Cells (SDC계 단실형 고체산화물 연료전지용 SDC-NiO 복합음극의 최적 환원 조건)

  • Min, Ji-Hyun;Ahn, Sung-Jin;Moon, Joo-Ho;Kim, Joo-Sun
    • 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.

Influence of the Binder Types on the Electrochemical Characteristics of Si-C Composites Electrode in LIBs (Si-C 복합체 전극의 바인더 종류에 따른 전기화학적 특성 변화)

  • Jung, Sung-Hun;Ji, Mijung;Park, Geunyeong;Hong, Jongill;Choi, Byung-Hyun
    • Journal of the Korean Ceramic Society
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    • v.50 no.2
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    • pp.168-172
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    • 2013
  • This work presents the effects of binders on the electrochemical performance of Si-C composites as the anode of lithium ion batteries. PAI (polyamide-imide) was used as an organic binder, and PAN (polyacrylonitrile), PAA (polyacrylic acid) and CMC + SBR (carboxymethyl cellulose + styrene-butadiene rubber) were used as aqueous binders. As a result, stabilization time for the cell with a Si-C composite anode synthesized using aqueous binders became shorter than an organic binder. Particularly in the case of the cell using PAA binder, better performance was observed in terms of adhesion strength, initial efficiency, the volume expansion ratio, Coulombic efficiency, and capacity retention.

Symmetrical Solid Oxide Electrolyzer Cells (SOECs) with La0.6Sr0.4Co0.2Fe0.8O3 (LSCF)-Gadolinium Doped Ceria (GDC) Composite Electrodes

  • Lee, Kyoung-Jin;Lee, Min-Jin;Park, Seok-hoon;Hwang, Hae-Jin
    • Journal of the Korean Ceramic Society
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    • v.53 no.5
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    • pp.489-493
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    • 2016
  • Scandia ($Sc2O_3$)-stabilized zirconia (ScSZ) electrolyte-supported symmetrical solid oxide electrolyzer cells (SOECs), in which lanthanum strontium cobalt ferrite (LSCF)-gadolinia ($Gd_2O_3$)-doped ceria (GDC) composite materials are used as both the cathode and anode, were fabricated and their high temperature steam electrolysis (HTSE) performance was investigated. Current density-voltage curves were obtained for cells operated in 10% $H_2O$/90% Ar at 750, 800, and $850^{\circ}C$. It was possible to determine the ohmic, cathodic, and anodic contributions to the total overpotential using the three-electrode technique. The HTSE performance was significantly improved in the symmetrical cell with LSCF-GDC electrodes compared to the cell consisting of an Ni-YSZ cathode and LSCF-GDC anode. It was found that the overpotential due to the LSCF-GDC cathode largely decreased and, at a given current density, the total cell voltage decreased, which resulted in the enhanced hydrogen production rate in the symmetrical cell.

Fe3O4 Nanoparticles on MWCNTs Backbone for Lithium Ion Batteries

  • Lee, Kangsoo;Shin, Seo Yoon;Yoon, Young Soo
    • Journal of the Korean Ceramic Society
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    • v.53 no.3
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    • pp.376-380
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    • 2016
  • A composite electrode made of iron oxide nanoparticles/multi-wall carbon nanotube (iNPs/M) delivers high specific capacity and cycle durability. At a rate of $200mAg^{-1}$, the electrode shows a high discharge capacity of ${\sim}664mAhg^{-1}$ after 100 cycles, which is ~ 70% of the theoretical capacity of $Fe_3O_4$. Carbon black, carbon nanotube, and graphene as anode materials have been explored to improve the electrical conductivity and cycle stability in Li ion batteries. Herein, iron oxide nanoparticles on acid treated MWCNTs as a conductive platform are combined to enhance the drawbacks of $Fe_3O_4$ such as low electrical conductivity and volume expansion during the alloying/dealloying process. Enhanced performance was achieved due to a synergistic effect between electrically 3D networks of conductive MWCNTs and the high Li ion storage ability of $Fe_3O_4$ nanoparticles (iNPs).

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.