• Journal of the Korean Electrochemical Society
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• v.6 no.1
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• pp.41-47
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• 2003

For the development of low temperature anode-supported planar solid oxide fuel cell, the planar anode supports with the thickness of 0.8 to 1 mm and the area of 25, 100 and $150\;cm^2$ were fabricated by the tape casting method. The strength, porosity, gas permeability and electrical conductivity of the planar anode support were measured. The porosity of anode supports sintered at $1400^{\circ}C$ and then reduced in$H_2$ atmosphere was increased from $45.8\%\;to\;53.9\%$. The electrical conductivity of the anode support was $900 S/cm\;at\; 850^{\circ}C$ and its gas permeability was 6l/min at 1 atm in air atmosphere. The electrolyte layer and cathode layer were fabricated by slurry dip coating method and then had examined the thickness of $10{\mu}m$ and the gas permeability of 2.5 ml/min at 3 atm in air atmosphere. As preliminary experiment, cathode multi-layered structure consists of LSM-YSZ/LSM/LSCF. At single cell test using the electrolyte layer with thickness of 20 to $30{\mu}m$, we achieved $300\;mA/cm^2$ and 0.6V at $750^{\circ}C$

• Journal of the Korean Electrochemical Society
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• v.11 no.1
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• pp.1-5
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• 2008

A Pt-layer was deposited on the anode side of a Nafion membrane via a sputtering method in order to reduce methanol crossover in a direct methanol fuel cell (DMFC). The methanol permeation and the proton conductivity through the modified membranes were investigated. The performances of the direct methanol fuel cell were also tested using single cells with a Nafion membrane and the modified membranes. The Pt-layers on the membrane blocked both methanol crossover and proton transport through the membranes. Methanol permeability and proton conductivity decreased with an increase of the platinum layer thickness. At methanol concentration of 2 M, the DMFC employing the modified membrane with a platinum layer of 66 nm-thickness showed similar performance to that of a DMFC with a bare Nafion membrane in spite of the lower proton conductivity of the former. The maximum power density of the cell using the modified membrane with a platinum layer of 66 nm-thickness increased slightly while that of the cell with the bare membrane decreased abruptly when a methanol solution of 6M was supplied.

• Macromolecular Research
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• v.13 no.6
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• pp.514-520
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• 2005

Composite membranes of Nafion and sulfonated poly(arylene ether sulfone) were prepared. Sulfonated poly(arylene ether sulfone)s with different degrees of sulfonation were blended with Nafion to reduce the methanol crossover. The morphology, proton conductivity and methanol permeability of the resulting composite membranes were investigated by SEM, EDAX, AC impedance spectroscopy and permeability measuring instrument. The cross­sections of the composite membranes showed a phase separated morphology. The morphology and phase separation mechanism could be controlled by varying the blend ratio and the degree of sulfonation of poly(arylene ether sulfone). These complex morphologies can be applied for reducing methanol crossover. The methanol permeability and proton conductivity of the composite membranes were lower than those of Nafion 117 membrane since the development of an ionic pathway in the blend membrane was more difficult than that in Nafion itself.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.749-753
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• 2012

In present work, anode support for micro-tubular SOFC was fabricated with outer diameter of 3 mm and characterized with microstructure, mechanical properties and gas permeability. The microstructure of surface and cross section of a porous anode support were analyzed by using SEM (Scanning Electron Microscope) image. The gas permeability and the mechanical strength of anode support was measured and analysed by using differential pressure at the flow rates of 50, 100, 150 cc/min. and using universal testing machine respectively. The unit cell composed of NiO-YSZ, YSZ, YSZ-LSM/LSM/LSCF was fabricated and operated with reaction temperature and fuel flow rate and showed maximum power density of $1095mW/cm^2$ on the condition of $800^{\circ}C$. The performance of single cell for micro-tubular SOFC increased with the increasing the reaction temperature due to the decrement of ohmic resistance of cell by the increment of the ionic conductivity of electrolyte through the evaluation of electrochemical impedance analysis for single cell with reaction temperature.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.1
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• pp.133-137
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• 2006

Ion permeability characteristics in nano-polymer membrane structures are performed to investigate the chemical composition and characteristics of MEA(Membrane Electrolyte Assembly) which is one of the most important parts to decide the performance in PEMFC(Polymer Electrolyte Membrane Fuel Cell) system. Subsequently, the MEA manufacturing process is presented for the uniformed MEA product. In the meantime, the analysis of SEM(Scanning Electron Microscope) is carried out in order to investigate the joint aspect and chemical composition of MEA. As a result of SEM analysis, it is found that the bonded catalyst and carbon composition contain the reasonable amount to get unit cell output. It is also found that the humidification gives the better performance result slightly.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.210-214
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• 2002

In this study, the coupled effect of electrokinetic and ultrasonic remediation technology was investigated for removing of heavy metal and organic matter at the same time. The laboratory tests were conducted using specially designed and fabricated electrokinetic and ultrasonic devices. The electrokinetic technique was applied to remove mainly the heavy metal and the ultrasonic technique was applied to remove mainly organic substance in contaminated soil. Diesel fuel and Cd were used as a surrogate contaminant for this test. A series of laboratory experiments involving electrokinetic and electrokinetic+ultrasonic flushing test were carried out. An increase in permeability and contaminant removal rate was observed in electrokinetic+ultrasonic flushing test.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.409-411
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• 2005

A series of inorganic-organic hybrid membranes were prepared with a systematic variation of titanium dioxidenanoparticles content. Their water uptake, methanol permeability and proton conductivity as a function of inorganic oxide content were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is also found that increase in inorganic oxide content leads to decrease of methanol permeability. In terms of the morphology, membranes are homogeneous and exhibit a good adhesion between inorganic domains and the polymer matrix. The properties of the composite membranes are compared with the standard nation membrane.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.90.2-90.2
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• 2010

The coated metallic bipolar plates are getting attractive due to their good feasibility of mass production, low contact resistance, high electrical/thermal conductivity, low gas permeability and good mechanical strength comparing with graphite materials. Yet, metallic bipolar plates for polymer electrolyte membrane(PEM) fuel cells typically require coatings for corrosion protection. Other requirements for the corrosion protective coatings include low electrical contact resistance between metallic bipolar plate and gas diffusion layer, good mechanical robustness, low mechanical and fabrication cost. The authors have evaluated a number of protective coatings deposited on stainless steel substrate by electroplating. The coated metallic bipolar plates are investigated with an electrochemical polarization tests, salt dipping tests, adhesion tests for corrosion resistance and then the contact resistance was measured. The results showed that the selective samples electroplated with optimized method, satisfied the DOE target for corrosion resistance and contact resistance, and also were very stabilized in the typical fuel cell environments in the long-term.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.260-263
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• 2005

The effects of internal manifold designs the reactant feed-stream in Polymer Electrolyte Fuel Cells (PEFCs) is studied to figure out mass flow-distribution patterns over an entire fuel cell stack domain. Reactants flows are modeled either laminar or turbulent depending on regions and the open channels in the bipolar plates are simulated by porous media where permeability should be pre-determined for computational analysis. In this work, numerical models for reactant feed-stream in the PEFC manifolds are classified into two major flow patterns: Z-shape and U-shape. Several types of manifold geometries are analyzed to find the optimal manifold configurations. The effect of heat generation in PEFC on the flow distribution is also investigated applying a simplified heat transfer model in the stack level (i.e. multi-cell electrochemical power-generation unit). This modeling technique is well suited for many large scale problems and this scheme can be used not only to account for the manifold flow pattern but also to obtain information on the optimal design and operation of a PEMC system.

• New & Renewable Energy
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• v.1 no.2 s.2
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• pp.41-52
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• 2005

The effects of internal manifold designs on the reactants feed-stream in Polymer Electrolyte Fuel Cells [PEFCs] is studied to figure out flow and thermal distribution patterns over an entire fuel cell stack. Reactants flows are modeled either laminar of turbulent depending on regions and the open channels in the bipolar plates are simulated by porous media where permeability should be pre-deter-mined for computational analysis. In this work, numerical models for reactants feed-stream In the PEFC manifolds are classified Into two major flow patterns: Z-shape and U-shape. Several types of manifold geometries are analyzed to find the optimal manifold configurations. The effect of heat generation in PEFC on the flow distribution is also Investigated applying a simplified heat transfer model in the stack level (i.e. multi-cell electrochemical power-generation unit). This modeling technique Is well suited for many large scale problems and this scheme can be used not only to account for the manifold flow pattern but also to obtain Information on the optimal design and operation of PEFC systems.