• Title/Summary/Keyword: Perovskite oxide anode

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Single cell property and numerical analysis of metal-supported solid oxide fuel cell (금속지지체형 고체산화물 연료전지의 단전지 특성 및 전산해석)

  • Lee, Chang-Bo;Bae, Joong-Myeon
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2222-2227
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    • 2007
  • Newly structured metal-supported solid oxide fuel cell was fabricated and characterized by impedance analysis and galvanodynamic experiment. Using a cermet adhesive, thin ceramic layer composed of anode(Ni/YSZ) and electrolyte(YSZ) was joined with STS430 metal support of which flow channel was fabricated. $La_{0.8}Sr_{0.2}Co_{0.4}Mn_{0.6}O_3$ perovskite oxide was used as cathode material. Single cell performance was increased and saturated at operating time to 300hours at 800$^{\circ}C$ because of cathode sintering effect. The sintering effect was reinvestigated by half cell test and exchange current density was measured as 0.005A/$cm^2$. Maximum power density of the cell was 0.09W/$cm^2$ at 800$^{\circ}C$. Numerical analysis was carried out to classify main factors influencing the single cell performances. Compared to experimental IV curve, simulated curve based on experimental parameters such as exchange current density was in good agreement.

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Characteristics of Sr0.92Y0.08Ti1-xVxO3-δ (x = 0.01, 0.04, 0.07, 0.12) Anode for Using H2S Containing Fuel in Solid Oxide Fuel Cells (H2S를 포함하는 연료를 사용하기 위한 고체산화물 연료전지용 Sr0.92Y0.08Ti1-xVxO3-δ 연료극 특성)

  • Jang, Geun Young;Kim, Jun Ho;Mo, Su In;Park, Gwang Seon;Yun, Jeong Woo
    • Korean Chemical Engineering Research
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    • v.59 no.4
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    • pp.557-564
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    • 2021
  • Sr0.92Y0.08Ti1-xVxO3-δ (SYTV) with perovskite structure was investigated as an alternative anode to utilize H2S containing fuels in solid oxide fuel cells. To improve the electrochemical performance of Sr0.92Y0.08TiO3-δ (SYT), vanadium(V) was substituted to titanium(Ti) at the B-site of the SYT perovskites. The SYTV synthesized by the Pechini method was chemically compatible with the YSZ electrolyte without additional by-products formation under the cell fabricating conditions. As increasing V substitution amounts, the oxygen vacancies increased, resulting to increasing ionic conductivity of the anode. The cell performance in pure H2 at 850 ℃ is 19.30 mW/cm2 and 34.87 mW/cm2 for a 1 mol.% and 7 mol.% of V substituted anodes, respectively. The cell performance using H2 fuel containing 1000 ppm of H2S at 850 ℃ was 23.37 mW/cm2 and 73.11 mW/cm2 for a 1 mol.% and 7 mol.% of V substituted anodes, respectively.

Synthesis characterization of a high conductivity LSCF cathode materials and electrochemical studies for IT-SOFC (중.저온 고체산화물 연료전지용 고전도성 공기극 소재 합성 및 전기화학적 특성 평가)

  • Kim, Hyoshin;Lee, Jongho;Kim, Ho-Sung;Lee, Yunsung
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.139-139
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    • 2010
  • LSM is widely used as a cathode material in SOFC, because of its high electrochemical activity, good stability and compatibility with YSZ electrolyte at high temperature. However, LSM in traditional cathode materials will not generate a satisfactory performance at intermediate temperature. In order to reduce the polarization resistance of cell with the operating temperature of SOFC system, the cathode material of LSCF is one of the most suitable electrode materials because of its high mixed ionic and electronic conductivity. In this report, cathode material, $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ powder for intermediate temperature SOFC was synthesized by Pechini method using the starting materials such as nitrate of La, Sr, Co and Fe including ethylene glycol, etc. As a result, the synthesized powder that calcined above $700^{\circ}C$ exhibits successfully perovskite structure, indicating phase-pure of LSCF. Moreover, the particle size, surface area, crystal structure and morphology of the synthesized oxide powders were characterized by SEM, XRD, and BET, etc. In order to evaluate the electrochemical performance for the synthesized powder, slury mixture using the synthesized cathode material was coated by screen-printing process on the anode-supported electrolyte which was prepared by a tape casting method and co-sintering. Finally, electrochemical studies of the SOFC unit cell, including measurements such as power density and impedance, were performed.

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Materials Chemical Point of View for Durability Issues in Solid Oxide Fuel Cells

  • Yokokawa, Harumi;Horita, Teruhisa;Yamaji, Katsuhiko;Kishimoto, Haruo;Brito, M.E.
    • Journal of the Korean Ceramic Society
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    • v.47 no.1
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    • pp.26-38
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    • 2010
  • Degradation in Solid Oxide Fuel Cell performance can be ascribed to the following fundamental processes from the materials chemical point of view; that is, diffusion in solids and reaction with gaseous impurities. For SOFC materials, diffusion in solids is usually slow in operation temperatures $800\sim1000^{\circ}C$. Even at $800^{\circ}C$, however, a few processes are rapid enough to lead to some degradations; namely, Sr diffusion in doped ceria, cation diffusion in cathode materials, diffusion related with metal corrosion, and sintering of nickel anodes. For gaseous impurities, chromium containing vapors are important to know how the chemical stability of cathode materials is related with degradation of performance. For LSM as the most stable cathode among the perovskite-type cathodes, electrochemical reduction reaction of $CrO_3$(g) at the electrochemically active sites is crucial, whereas the rest of the cathodes have the $SrCrO_4$ formation at the point where cathodes meet with the gases, leading to rather complicated processes to the degradations, depending on the amount and distribution of reacted Cr component. These features can be easily generalized to other impurities in air or to the reaction of nickel anodes with gaseous impurities in anode atmosphere.

Cathode Materials LaNi1−xCuxO3 for Low Temperature Solid Oxide Fuel Cells

  • Sun, Juncai;Wang, Chengli;Li, Song;Ji, Shijun
    • Journal of the Korean Ceramic Society
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    • v.45 no.12
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    • pp.755-759
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    • 2008
  • New cathode materials $LaNi_{1-x}{Cu_x}{O_3}$ (typically $LaNi_{0.8}Cu_{0.2}O_3$) were synthesized using a co-precipitation method. The structure and morphology of the powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The composite material [$Ce_{0.8}Sm_{0.2}O_{2-\ddot{a}}$(SDC) and carbonate (${Na_2}{CO_3},{Li_2}{CO_3}$)], NiO and $LaNi_{1-x}{Cu_x}{O_3}$ were used as the electrolyte, anode and cathode, respectively. The electrochemical performance of La-Ni-Cu-O perovskite oxide at low temperatures ($400{\sim}550^{\circ}C$) was studied. The results showed that $LaNi_{0.8}Cu_{0.2}O_3$ precursor powder prepared through a co-precipitation method and calcined at $860^{\circ}C$ for 2 h formed uniform grains with diameters in the range of $400{\sim}500\;nm$. The maximum power density and the short circuit current density of the single cell unit at $550^{\circ}C$ were found to be $390\;mW/cm^2$ and $968\;mA/cm^2$, respectively.

Development of Cobalt-free $La_xSr_{4-x}Fe_6O_{13}$ ($0{\leq}x{\leq}2$) Intergrowth Cathode Material for Solid Oxide Fuel Cells

  • Lee, Seung-Jun;Yong, Seok-Min;Kim, Dong-Seok;Kim, Do-Gyeong
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.45.1-45.1
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    • 2011
  • Cobalt-free $La_xSr_{4-x}Fe_6O_{13}$ ($0{\leq}x{\leq}2$) oxide have been synthesized and investigated as a potential cathode material for solid oxide fuel cells (SOFCs). $Sr_4Fe_6O_{13}$ consists of alternating perovskite layers ($Sr_4Fe_2O_8$) containing iron cations in octahedral oxygen coordination and $Fe_4O_5$ layers where iron cations have 5-fold coordination of two types-square pyramids and trigonal bipyramids. Our preliminary electrochemical testes of pristine $Sr_4Fe_6O_{13}$ show a rather high area specific resistance ($0.47{\Omega}cm^2$ at $700^{\circ}C$) for ~20 ${\mu}m$ thick layers with CGO electrolyte. The electrochemical performances are improved by La addition up to x=1 ($La_1Sr_3Fe_6O_{13}$, $0.06{\Omega}cm^2$ at $700^{\circ}C$). In addition, thermal expansion coefficient (TEC) values of $La_1Sr_3Fe_6O_{13}$ specimen demonstrated $15.1{\times}10^{-6}\;^{\circ}C^{-1}$ in the range of 25-900$^{\circ}C$, which provides good thermal expansion compatibility with the CGO electrolyte. An electrolyte supported (300-${\mu}m$-thick) single-cell configuration of $La_1Sr_3Fe_6O_{13}$/CGO/Ni-CGO delivered a maximum power density of 584 $mWcm^{-2}$ at $700^{\circ}C$. In addition, an anode supported single cell by YSZ electrolyte (10-${\mu}m$-thick) with a porous CGO interlayer between the cathode and the electrolyte to avoid undesired interfacial reactions exhibited 1,517 $mWcm^{-2}$ at $800^{\circ}C$. The unique composition of $La_1Sr_3Fe_6O_{13}$ with low thermal expansion coefficient and higher electrochemical properties could be a good cathode candidate for intermediate temperature SOFCs with CGO and YSZ electrolyte.

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BaCeO3-BaZrO3 Solid Solution (BCZY) as a High Performance Electrolyte of Protonic Ceramic Fuel Cells (PCFCs) (BaCeO3-BaZrO3 고용체(BCZY) 기반 프로톤 세라믹 연료전지(PCFC)용 고성능 전해질 개발)

  • An, Hyegsoon;Shin, Dongwook;Choi, Sung Min;Lee, Jong-Ho;Son, Ji-Won;Kim, Byung-Kook;Je, Hae June;Lee, Hae-Weon;Yoon, Kyung Joong
    • Journal of the Korean Ceramic Society
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    • v.51 no.4
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    • pp.271-277
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    • 2014
  • To overcome the limitations of the solid oxide fuel cells (SOFCs) due to the high temperature operation, there has been increasing interest in proton conducting fuel cells (PCFCs) for reduction of the operating temperature to the intermediate temperature range. In present work, the perovskite $BaCe_{0.85-x}Zr_xY_{0.15}O_{3-\delta}$ (BCZY, x = 0.1, 0.3, 0.5, and 0.7) were synthesized via solid state reaction (SSR) and adopted as an electrolyte materials for PCFCs. Powder characteristics were examined using X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer, Emmett and Teller (BET) surface area analysis. Single phase BCZY were obtained in all compositions, and chemical stability was improved with increasing Zr content. Anode-supported cell with $Ni-BaCe_{0.55}Z_{0.3}Y_{0.15}O_{3-\delta}$ (BCZY3) anode, BCZY3 electrolyte and BCZY3-$Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-\delta}$ (BSCF) composite cathode was fabricated and electrochemically characterized. Open-circuit voltage (OCV) was 1.05 V, and peak power density of 370 ($mW/cm^2$) was achieved at $650^{\circ}C$.