• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.4
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• pp.381-385
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• 2005

The plasma temperature of Ar gas in hollow cathode discharge were measured. This is done by measuring the line profile of the 1s/sub 8/-2p/sub 8/ transition in Ar, using a single-frequency diode laser. Low power diode lasers have been successfully used for investigation of the line profiles of Ar transitions in hollow cathode discharges. It turns out that the plasma temperature of Ar is 640∼783 K in the discharge current range at 7∼10 mA.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.5
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• pp.471-477
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• 2007

SCBF(Spherically Convergent Beam Fusion) device has been studied as a neutron source. Neutron production rate is a most important factor for the application of SCBF device and is proportional to the square of the ion current[1]. It is regarded generally that some correlations between the potential well structure and the ion current exist. In this paper, the ion current and potential distribution were calculated in a variety of grid cathode geometries using FEM-FCT method. Single potential well structure was certified inside the grid cathode. The deeper the potential well became, the higher the ion current due to the high electric field near the grid cathode became.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.30-31
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• 2006

The LSCF cathode for Solid Oxide Fuel Cell was investigated to develop high performance unit cell at intermediate temperature by modified oxalate method with different electrolyte. The LSCF precursors using oxalic acid, ethanol and $NH_4OH$ solution were prepared at $80^{\circ}C$, and pH was controlled as 2, 6, 7, 8, 9 and 10. The synthesis precursor powders were calcined at $800^{\circ}C$, $1000^{\circ}C$ and $1200^{\circ}C$ for 4hrs. Unit cells were prepared with the calcined LSCF cathode, buffer layer between cathode and each electrolyte that is the LSGM, YSZ, ScSZ and CeSZ. The synthesis LSCF powders by modified oxalate method were measured by scanning electron microscope and X-ray diffraction. The interfacial polarization resistance of cell was characterized by Solatron 1260 analyzer. The crystal of LSCF powders show single phase at pH 2, 6, 7, 8 and 9, and the average particle size was about $3{\mu}m$. The electric conductivity of synthesis LSCF cathode which was calcined at $1200^{\circ}C$ shows the highest value at pH 7. The cell consist of GDC had the lowest interfacial resistance (about 950 S/cm@650) of the cathode electrode. The polarization resistance of synthesis LSCF cathode by modified oxalate method has the value from 4.02 to 7.46ohm at $650^{\circ}C$. GDC among the electrolytes, shows the lowest polarization resistance.

• Journal of the Korean Ceramic Society
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• v.55 no.4
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• pp.358-363
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• 2018

To improve the polarization property of cathodes, which is the main factor limiting the performance of protonic ceramic fuel cells (PCFCs), $K_2NiF_4-type$ $Pr_2NiO_{4+{\delta}}$, which is expected to exhibit a triple conducting property (proton, oxygen ion, and hole conductions) was applied to PCFCs and its properties were investigated. Low-temperature microwave heat-treatment was used to achieve both sufficient interface adhesion between the electrolyte and the cathode layers and suppression of the secondary phase formation due to migration of elements such as barium and cerium. Through this fabrication method, a high performance of $0.82W{\cdot}cm^{-2}$ and low ohmic resistance of $0.06{\Omega}{\cdot}cm^2$ were obtained in an $Ni-BaCe_{0.55}Zr_{0.3}Y_{0.15}O_{3-{\delta}}$ | $BaCe_{0.55}Zr_{0.3}Y_{0.15}O_{3-{\delta}}$ | $Pr_2NiO_{4+{\delta}}$ single cell at $650^{\circ}C$. This result verifies that the $K_2NiF_{4+{\delta}}-type$ cathode shows good chemical compatibility which, in turn, will make it a potent candidate as a PCFC cathode.

• Journal of the Semiconductor & Display Technology
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• v.7 no.1
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• pp.29-34
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• 2008

In this paper, the DE(double erosion) cathode for the reactive magnetron sputtering system is developed for high deposition rate and high target utilization efficiency. The utilization efficiency of the developed DE cathode is 22% higher than that of normal SE(single erosion) cathode. Sputtering process for the nickel oxide thin films with the DE cathode is performed under the following conditions; power with $1kW{\sim}3kW$, pressure with 4mtorr and 8mtorr, oxygen flow ratio with $0%{\sim}80%$. As a result, the hysteresis phenomenon of discharge voltage in 4mtorr is lower than that in 8mtorr and the hysteresis phenomenon of discharge voltage is getting lower as the applied power is getting higher. The structure of cross section and surface roughness of the thin films are observed by FE-SEM and AFM. The structure of cross section of the thin films is columnar and the average surface roughness under oxygen flow ratio of 0%, 52.5% and 65.0% are $2.08{\AA}$, $2.20{\AA}$ and $0.854{\AA}$, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.9
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• pp.583-588
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• 2017

Thermal batteries are used in military power sources that require robustness and long storage life for applications in missiles and torpedoes. $FeS_2$ powder is currently used as a cathode material because of its high specific energy density, environmental non-toxicity, and low cost. $MS_2$ (M = Fe, Ni, Co) cathodes have been explored as novel candidates for thermal batteries in many studies; however, the discharge characteristics (1, 2, 3 plateau) of single cells in thermal batteries with different cathodes have not been elucidated in detail. In this study, we independently analyzed the discharge voltage and calculated the total polarizations of single cells using $MS_2$ cathodes. Based on the results of this study, we propose $NiS_2$ as a potential cathode material for use in thermal batteries.

• Korean Journal of Materials Research
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• v.18 no.5
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• pp.277-282
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• 2008

The effects of the field emission property in relation to the surface morphology and adhesion force were investigated. The single-wall-nanotube-based cathode was obtained by use of an in-situ arc discharge synthesis method, a screen-printing method and a spray method. The morphologies of the formed emitter layers were very different. The emission stability and uniformity were dramatically improved by employing an in-situ arc discharge synthesis method. In this study, it was confirmed that the current stability and uniformity of the field emission of the cathode depend on the surface morphology and adhesion force of the emitters. The current stability of the field emission device was also studied through an electrical aging process by varying the current and electric field.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.550-556
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• 2022

The performance of enzymatic fuel cells that convert chemical energy contained in various organic molecules such as sugar, alcohol, organic acids, and amino acids into electrical energy is greatly affected by the cathode as well as the anode. This study aimed to develop a laccase-based cathode with high performance. An enzyme composite composed of an laccase, redox mediator, and carbon nanotubes was immobilized on the surface of electrode in multiple layers, and the effect of the number of layers and the presence or absence of carbon nanotubes on electrode performance was investigated. As the number of layers of the enzyme-mediator (Lac-(PVI-Os-dCl)) on the electrode surface increased, the amount of reduction current generated at the electrode increased. The enzyme-carbon nanotube-mediator composite electrode (Lac-SWCNTs-(PVI-Os-dCl)) generated a current 1.7 times greater than that of the Lac-(PVI-Os-dCl). It was found that the largest amount of current (10.1±0.1 µA) was generated in the electrode composed of two layers of Lac-(PVI-Os-dCl) and two layers of Lac-SWCNTs-(PVI-Os-dCl) in the evaluation of electrodes with different ratio of Lac-SWCNTs-(PVI-Os-dCl) and Lac-(PVI-Os-dCl). The maximum power density of the cell using the cathode composed of a single layer of Lac-(PVI-Os-dCl) and the cell using the optimized cathode were 0.46±0.05 and 1.23±0.04 µW/cm², respectively. In this study, it was demonstrated that the performance of cathode and the enzymatic fuel cell using the same can be improved by optimizing the layers of composites composed of laccase, redox mediator, and carbon nanotubes on the electrode surface.

• Advances in Energy Research
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• v.2 no.1
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• pp.21-31
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• 2014

The use of a microporous membrane along with Au/C catalyst for direct glycerol alkaline fuel cell was investigated. In comparison with Nafion 112, the microporous Celgard 3401 membrane provides a better cell performance due to the lower ionic resistance as confirmed by impedance spectra. The single cell using Au/C as anode catalyst prepared by using PVA protection techniques provided a higher maximum power density than the single cell with commercial PtRu/C at $18.65mW\;cm^{-2}$ The short-term current decay studies show a better stability of Au/C single cell. The higher activity of Au/C over PtRu/C was owing to the lower activation loss of Awe. The magnitude of current decay indicates a low problem of glycerol crossover from anode to cathode side. The similar performance of single cell with and without humudification at cathode points out an adequate transport of water through the microporous membrane.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.487-492
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• 2011

The effect of the application of lanthanum strontrium manganite and yttria-stabilized zirconia (LSM-YSZ) nano-composite fabricated by pulsed laser deposition (PLD) as a cathode of solid oxide fuel cell (SOFC) is studied. A gradient-structure thin-film cathode composed of 1 micron-thick LSM-YSZ deposited at an ambient pressure ($P_{amb}$) of 200 mTorr; 2 micron-thick LSM-YSZ deposited at a $P_{amb}$ of 300 mTorr; and 2 micron-thick lanthanum strontium cobaltite (LSC) current collecting layer was fabricated on an anode-supported SOFC with an ~8 micron-thick YSZ electrolyte. In comparison with a 1 micron-thick nano-structure single-phase LSM cathode fabricated by PLD, it was obviously effective to increase triple phase boundaries (TPB) over the whole thickness of the cathode layer by employing the composite and increasing the physical thickness of the cathode. Both polarization and ohmic resistances of the cell were significantly reduced and the power output of the cell was improved by a factor of 1.6.