• Title/Summary/Keyword: Porous Electrode

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Modified Agglomerated Film Model Applied to a Molten Carbonate Fuel Cell Cathode (실측자료를 이용한 Agglomerated Film Model의 용융탄산염 연료전지 산소전극 성능모사)

  • 임준혁;김태근
    • Journal of Environmental Science International
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    • v.5 no.5
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    • pp.593-603
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    • 1996
  • A dual-porosity filmed agglomerate model for the porous cathode of the molten carbonate fuel has been investigated to predict the cell performance. A phenomenological treatment of molecular, kinetic and electrode parameters has been given. The major physical and chemical phenomena being modeled include mass transfer, ohmic losses and reaction kinetics at the electrode- electrolyte interface. The model predicts steady-state cell performance, given the above conditions that characterize the state of the electrode. Quasi-linearization and finite difference techniques are used to solve the coupled nonlinear differential equations. Also, the effective surface area of electrode pore was obtained by mercury porosimeter. The results of the investigation are presented in the form of plots of overpotential vs. current density with varied the electrode material, gas composition and mechanism. The predicted polarization curves are compared with the empirical data from 1 c$m^2$ cell. A fair correspondence is observed.

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CoMn Oxide/Carbon-nanofiber Composite Electrodes for Supercapacitors (코발트망간 산화물/탄소나노섬유 복합전극의 수퍼케폐시터 특성)

  • Kim, Yong-Il;Yoon, Yu-Il;Ko, Jang-Myoun
    • Journal of the Korean Ceramic Society
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    • v.45 no.8
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    • pp.493-496
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    • 2008
  • Composite electrodes consisting of $CoMnO_2$ and carbon nanofibers(vapor grown carbon nanofiber, VGCF) with high electrical conducivity($CoMnO_2$/VGCF) were prepared on a porous nickel foam substrate as a current collector and their supercapacitive properties were investigated using cyclic voltammetry in 1 M KOH aqueous solution. The $CoMnO_2$/VGCF electrode exhibited high specific capacitance value of 630 F/g at 5 mV/s and excellent capacitance retention of 95% after $10^4$ cycles, indicating that the used VGCF played the important roles in reducing the interfacial resistance in the composite electrode to improve supercapacitive performance.

A Study on the ZnO Supported Silica Gel (ZnO가 담지된 실리카 겔 연구)

  • Kim, S.Y.;Kim, M.Y.;Ju, C.S.
    • Journal of Power System Engineering
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    • v.15 no.4
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    • pp.75-78
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    • 2011
  • There are various types of materials used in electronic industry, such as electrode material, conductor, insulator, anode, cathode and semiconductor. Electrode material type is Cu, Ti, ZnO and so on. Especially if we use mixed ZnO in soil cement or silica gel, we can have advantages in ice road to prevent freezing. We have great impact if we use supported in inorganic substances like silica gel. In this paper we have studied that ZnO supported silica gel and its properties. Zinc acetate dissolved in distilled water were loaded on the silica gel by the reaction with ammonia at $80^{\circ}C$. And we investigated particle structures of ZnO by scanning electron microscopy(SEM) and X-ray diffraction(XRD).

Ballistic Electron Emitter using Nanocrystallized Poly-Si (Nanocrystallized Poly-Si을 이용한 Ballistic 전자 에미터)

  • Choi, Yong-Woon;Lee, Byung-Cheol
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.489-490
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    • 2008
  • As anodizing method using poly-Si (polycrystalline silicon) grown by LPCVD (Low Pressure Chemical Vapor Deposition), a ballistic electron emitter was made. An OPPS (Oxidized Porous Poly-Si) structure can generate ballistic electron which can pass through without scattering owing to electric field of oxide layer wrapped around nanocrystal due to applied voltage of between surface and bottom electrode. As electrode, (Al, Au and Pt/ti) were used. In this case, there were the better characteristics in Al and Pt/ti than in Al and Au.

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Effects of Electrolyte Concentration and Relative Cathode Electrode Area Sizes in Titania Film Formation by Micro-Arc Oxidation

  • Lee, Yong-K.;Lee, Kang-Soo
    • Corrosion Science and Technology
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    • v.9 no.4
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    • pp.171-174
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    • 2010
  • MAO (micro-arc oxidation) is an eco-friendly convenient and effective technology to deposit high-quality oxide coatings on the surfaces of Ti, Al, Mg and their alloys. The roles of the electrolyte concentration and relative cathode electrode area sizes in the grown oxide film during titanium MAO were investigated. The higher the concentration of the electrolyte, the lower the $R_{total}A$ value. The oxide film produced by the lower concentration of the electrolyte is thinner and less uniform than the film by the higher concentration, which is thick and porous. The cathode area size must be bigger than the anode area size in order to minimize the voltage drop across the cathode. The ratio of the cathode area size to the anode area size must be bigger than 8. Otherwise, the cathode will be another source for voltage drop, which is detrimental to and slows down the oxide growth.

Study on the surface porosity of porous thin layer electrode for phosphoric acid fuel cell (인산형 연료전지용 다공성 박막의 표면 다공도에 관한 연구)

  • 김조웅;김영우;이주성
    • Journal of the Korean institute of surface engineering
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    • v.24 no.3
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    • pp.162-168
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    • 1991
  • Gas diffusion and electrolyte penetration in wetproofed gas diffusion electrodes were studied using layers of PTFE- bonded carbon. Minor variations in fabrication and testing procedures resulted in very large variations in catalyst layer wetting characteristics and permiability for reaction gas. By controlling the pore size of gas diffusion electrode carefully by varing the PTFE contents, baking temperature, baking time and ammonium bicarbonate as additive, the primary pore was decreased and the secondary pore was increased and so more reaction gas through the primary pore could be reacted at catalyst agglomertes in the secondary pore. And the cathode current density was increased to more than 400mA.$\textrm{cm}^2$ and Tafel slope value was decreased to lower than 110mA/decade.

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Composite Ni-TiO2 nanotube arrays electrode for photo-assisted electrolysis

  • Pozio, Alfonso;Masci, Amedeo;Pasquali, Mauro
    • Advances in Energy Research
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    • v.3 no.1
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    • pp.45-57
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    • 2015
  • This article is addressed to define a new composite electrode constituted by porous nickel and an array of highly ordered $TiO_2$ nanotubes obtained by a previous galvanostatic anodization treatment in an ethylene glycol solution. The electrochemical performances of the composite anode were evaluated in a photo-electrolyser, which showed good solar conversion efficiency with respect to the UV irradiance together with a reduction of energy consumption. Such a combination of materials makes our system simple and able to work both in dark and under solar light exposure, thus opening new perspectives for industrial-scale applications.

Titanium Oxide Nanotube Arrays for Quartz Ctystal Microbalance (수정진동자 미세저울을 위한 티타늄산화물 나노튜브 어레이)

  • Mun, Kyu-Shik;Yang, Dae-Jin;Park, Hun;Choi, Won-Youl
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.372-372
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    • 2007
  • Titanium oxide nanotube arrays were fabricated by the anodization of pure titanium thin film deposited at $500^{\circ}C$ on silicon substrates. The titania nanotubes were grown by anodization in nonaqueous-base electrolytes at different potentials between 5 V and 30 V. $TiO_2$ nanotube array with a small pore diameter of 40 nm and long titanium oxide layer of $4\;{\mu}m$ was obtained. The $TiO_2$ nanotube array was used as a porous electrode for quartz crystal microbalance (QCM). Nanoporous morphology of electrode will increase the sensitivity of microbalance.

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Dehydration by Electro-osmosis on Ceramic Body (Electro-osmosis에 의한 Dehydration)

  • Han, Sang-Mok
    • Journal of Industrial Technology
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    • v.4
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    • pp.43-46
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    • 1984
  • In process of water removing safely from plastic clay, an electric field applied to a wet, porous solid such as day usually causes the rapid dehydration. The water-bearing positive ions move to negative electrode under the d. c. electrical stress or field. Therefore application of electro-osmosis to wet clay could include drying thick and large-scale ceramic body quickly and evenly. The d. c. power supply unit to 60 volts is necessary for safe practice. Also wider contact area and shorter distance between electrodes accelerate effectively the removal of water.

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