• Title/Summary/Keyword: Solid oxide cells

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Development of Reduced Temperature Solid Oxide Fuel Cells and Test of a Short Stack (저온형 고체산화물 연료전지의 개발과 이를 이용한 소형 스택의 성능 시험)

  • 유영성;박진우;임희천;이규창;조남웅
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 2003.05a
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    • pp.649-653
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    • 2003
  • 일반적으로 연료전지에는 알카리형(AFC)과 인산형(PAFC), 고분자형 연료전지(PEMFC) 등과 같이 비교적 저온에서 동작되는 연료전지와 고온형으로 $650^{\circ}C$에서 정온 동작되는 용융탄산염형 연료전지(MCFC)와 운전온도가 약 500~100$0^{\circ}C$로 폭넓게 적용될 수 있는 고체산화물 연료전지(혹은 고체전해질 연료전지, Solid Oxide Fuel Cell, SOFC)가 있다.(중략)

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Performance Simulation of Planar Solid Oxide Fuel Cells Characteristics: Computational Fluid Dynamics (전산 유체 모델링을 이용한 평판형 고체산화물 연료전지 작동특성 전산모사)

  • Woo Hyo Sang;Chung Yong-Chae
    • Journal of the Korean Electrochemical Society
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    • v.7 no.2
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    • pp.69-79
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    • 2004
  • To correctly simulate performance characteristics of fuel cells with a modeling method, various physical and chemical phenomena must be considered in fuel cells. In this study, performance characteristics of planar solid oxide fuel cells were simulated by a commercial CFD code, CFD-ACE+. Through simultaneous considerations for mass transfer, heat transfer and charge movement according to electrochemical reactions in the 3-dimensional planar SOFC unit stack, we could successfully predict performance characteristics of solid oxide fuel cells under operation for structural and progress variables. In other words, we solved mass fraction distribution of reactants and products for diffusion and movement, and investigated qualitative and quantitative analysis for performance characteristics in the SOFC unit stack through internal temperature distribution and polarization curve for electrical characteristics. Through this study, we could effectively predict performance characteristics with variables in the unit stack of planar SOFCs and present systematic approach for SOFCs under operation by computer simulation.

Sulfur Poisoning of Ni Anode as a Function of Operating Conditions in Solid Oxide Fuel Cells (고체산화물 연료전지의 운전 조건에 따른 니켈 전극 황 피독 현상)

  • Lee, Ho Seong;Lee, Hyun Mi;Lim, Hyung-Tae
    • Korean Journal of Metals and Materials
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    • v.56 no.12
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    • pp.893-899
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    • 2018
  • In the present study, we investigated the sulfur poisoning of the Ni anode in solid oxide fuel cells (SOFCs) as a function of operating conditions. Anode supported cells were fabricated, and sulfur poising tests were conducted as a function of current density, $H_2S$ concentration and humidity in the anode gas. The voltage drop was significant under the higher current density (${\sim}714mA/cm^2$) condition, while it was much reduced under the lower current density (${\sim}389mA/cm^2$) condition, at 100 ppm of $H_2S$. A secondary voltage drop, which occurred only at the high current density, was attributed to Ni oxidation in the anode. Thus, operation at high current density with high $H_2S$ concentration may lead to permanent deterioration in the anode. The effect of water content (10%) on the sulfur poisoning was also investigated through a constant current test (${\sim}500mA/cm^2$) at 10 ppm of $H_2S$. The cell operating with 10% wet anode gas showed a much smaller initial voltage drop, in comparison with a dry anode gas. The present study indicates that operating conditions, such as gas humidity and current density, should be carefully taken into account, especially when fuel cells are operated with $H_2S$ containing fuel.

Methodology for removing unreacted low-hydrocarbons in diesel reformate for stable operation of solid oxide fuel cells (안정적인 SOFC 운전을 위한 디젤 개질기 내 미반응 저탄화수소 제거법)

  • Yoon, Sang-Ho;Bae, Joong-Myeon;Lee, Sang-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.773-776
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    • 2009
  • In this paper, new concept of the diesel fuel processing is introduced for the stable operation of solid oxide fuel cells (SOFCs). Heavier hydrocarbons than $CH_4$, such as ethylene, ethane, propane, and etc., induce the carbon deposition on anode of SOFCs. In the reformate of heavy hydrocarbons (diesel, gasoline, kerosene, and JP-8), concentration of ethylene is usually higher than low hydrocarbons such as ethane, propane, and butane. So, removal of low hydrocarbons (over C1-hydrocarbons), especially ethylene, at the reformate gases is important for stable operation of SOFCs. New methodology as named "post-reformer" is introduced for removing the low hydrocarbons at the reformate gas stream. Catalyst of the NECS-PR4 is selected for post-reforming catalyst because the catalyst of NECS-PR4 shows the high selectivity for removing low hydrocarbons and achieving the high reforming efficiency. The diesel reformer and post-reformer are continuously operated for about 200 hours as integrated mode. The reforming performance is not degraded and low hydrocarbons in the diesel reformate are completely removed.

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Cathode Microstructure Control and Performance Improvement for Low Temperature Solid Oxide Fuel Cells (저온 고체산화물 연료전지용 공기극 미세구조 제어 및 성능개선)

  • Kang, Jung-Koo;Kim, Jin-Soo;Yoon, Sung-Pil
    • Journal of the Korean Ceramic Society
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    • v.44 no.12
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    • pp.727-732
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    • 2007
  • In order to fabricate a highly performing cathode for low-temperature type solid oxide fuel cells working at below $700^{\circ}C$, electrode microstructure control and electrode polarization measurement were performed with an electronic conductor, $La_{0.8}Sr_{0.2}MnO_3$ (LSM) and a mixed conductor, $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$(LSCF). For both cathode materials, when $Sm_{0.2}Ce_{0.8}O_2$ (SDC) buffer layer was formed between the cathode and yttria-stabilized zirconia (YSZ) electrolyte, interfacial reaction products were effectively prevented at the high temperature of cathode sintering and the electrode polarization was also reduced. Moreover, cathode polarization was greatly reduced by applying the SDC sol-gel coating on the cathode pore surface, which can increase triple phase boundary from the electrolyte interface to the electrode surface. For the LSCF cathode with the SDC buffer layer and modified by the SDC sol-gel coating on the cathode pore surface, the cathode resistance was as low as 0.11 ${\Omega}{\cdot}cm^2$ measured at $700^{\circ}C$ in air atmosphere.

Effect of Metal Ni Atomic Layer Deposition Coating on Ni/YSZ, Anode of Solid Oxide Fuel Cells (SOFCs) (고체산화물 연료전지의 Anode인 Ni/YSZ에 Ni 원자층 증착 코팅의 효과)

  • Kim, Jun Ho;Mo, Su In;Park, Gwang Seon;Kim, Hyung Soon;Kim, Do Heyoung;Yun, Jeong Woo
    • Journal of the Microelectronics and Packaging Society
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    • v.29 no.1
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    • pp.61-66
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    • 2022
  • This study is to increase the surface area and maximize the effect of the catalyst by coating a nanometersized metal catalyst material on the anode layer using atomic layer deposition (ALD) technology. ALD process is known to produce uniform films with well-controlled thickness at the atomic level on substrates. We measured the performance by coating metals (Ni) on Ni/YSZ, which is the most widely known anode material for solid oxide fuel cells. ALD coatings began to show a decrease in cell performance over 3 nm coatings.

Physical Property Models and Single Cells Analysis for Solid Oxide Fuel Cell (고체산화물 연료전지를 위한 물성치 모델 및 단전지 해석)

  • Park, Joon-Guen;Kim, Sun-Young;Bae, Joong-Myeon
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.379-381
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    • 2009
  • The simulation model for metal-supported Solid Oxide Fuel Cell(SOFC) is developed in this study. Open circuit voltage is calculated using Nernst equation and Gibbs free energy is required by thermodynamic. The exchange current densities are compared with experimental results since exchange current density is most effective factor for the activation loss. Liu's study is used for the exchange current density of cathode, BSCF, and Koide's result is applied for the exchange current density of anode, Ni/YSZ. For the ohmic loss, ionic conductivity of YSZ is described from Kilner's mode and the data are compared with Wanzenberg's experimental data. Diffusivity is an important factor for the mass transfer through the porous medium. Both binary diffusion and Knudsen diffusion are considered as the diffusion mechanism. For validation, simulation results at this work are compared with our experimental results.

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Development of Tubular Solid Oxide Fuel Cell (원통형 고체산화물 연료전지 기술개발)

  • Song, Rak-Hyun
    • 유체기계공업학회:학술대회논문집
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    • 2001.11a
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    • pp.373-380
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    • 2001
  • Solid Oxide Fuel Cells (SOFCs) have received considerable attention because of the advantages of high effiiciency, low pollution, cogeneration application and excellent integration with simplified reformer In this paper, we reported development of anode-tubular SOFC by wet process. For making tubular cell, Ni-cermet YSZ anode tube was fabricated using extrusion process, and YSZ electrolyte layer and LSM-YSZ composite, LSM, LSCF cathode layer were coated onto the anode supported tube using slurry dipping process and sintered by co-firing process. By using this tubular cell, we fabricated single cell consisted of the various cathode layers and 4 cell stack with an effective area of $75 cm^2$ per single cell, and evaluated their performance characteristics.

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Control of solid oxide fuel cell ceramic interfaces via atomic layer deposition (원자층 증착법을 통한 고체산화물 연료전지의 세라믹 인터페이스 제어)

  • Seo, Jongsu;Jung, WooChul;Kim, Jeong Hwan
    • Ceramist
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    • v.23 no.2
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    • pp.132-144
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    • 2020
  • Solid oxide fuel cell (SOFC) have attracted much attention due to clean, efficient and environmental-friendly generation of electricity for next-generation energy conversion devices. Recently, many studies have been reported on improving the performance of SOFC electrodes and electrolytes by applying atomic layer deposition (ALD) process, which has advantages of excellent film quality and conformality, and precise control of film thickness by utilizing its unique self-limiting surface reaction. ALD process with these advantages has been shown to provide functional ceramic interfaces for SOFC electrodes and electrolytes. In this article, recent examples of successful functionalization and stabilization on SOFC electrodes and electrolytes by the application of ALD process for realizing high performance SOFC cells are reported.