• Journal of the Korean institute of surface engineering
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• v.51 no.1
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• pp.47-53
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• 2018

Sn-based lithium-ion batteries have low cost and high theoretical specific capacity. However, one of major problem is the capacity fading caused by volume expansion during lithiation/delithiation. In this study, 3-dimensional foam structure of Cu-Sn alloy is prepared by co-electrodeposition including large free space to accommodate the volume expansion of Sn. The Cu-Sn foam structure exhibits highly porous and numerous small grains. The result of EDX mapping and XPS spectrum analysis confirm that Cu-Sn foam consists of $SnO_2$ with a small quantity of CuO. The Cu-Sn foam structure electrode shows high reversible redox peaks in cyclic voltammograms. The galvanostatic cell cycling performances show that Cu-Sn foam electrode has high specific capacity of 687 mAh/g at a current rate of 50 mA/g. Through SEM observation after the charge/discharge processes, the morphology of Cu-Sn foam structure is mostly maintained despite large volume expansion during the repeated lithiation/delithiation reactions.

• Journal of the Korean Ceramic Society
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• v.54 no.5
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• pp.438-442
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• 2017

This paper reports the facile synthesis of microlamella-structured porous copper (Cu)-oxide-based electrode and its potential application as an advanced anode material for lithium-ion batteries (LIBs). Nanowire-like Cu oxide, which is created by a simple thermal oxidation process, is radially and uniformly formed on the entire surface of Cu foam that has been fabricated using a combination of water-based slurry freezing and sintering (freeze casting). Compared to the Cu foil with a Cu oxide layer grown under the same processing conditions, the Cu foam anode with 63% porosity exhibits over twice as much capacity as the Cu foil (264.2 vs. 131.1 mAh/g at 0.2 C), confirming its potential for use as an anode electrode for LIBs.

• Journal of the Korea Safety Management & Science
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• v.1 no.1
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• pp.241-258
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• 1999

For hazardous air pollutants(HAP) such as NO and $NO_{2}$ decomposition efficiency, power consumption, and applied voltage were investigated by SPCP(surface induced discharge plasma chemical processing) reactor to obtain optimum process variables and maximum decomposition efficiencies. Decomposition efficiency of HAP with various electric frequencies(5~50 kHz), flow rates(100~1,000 mL/min), initial concentrations(100~1,000 ppm), electrode materials(W, Cu, Al), electrode thickness(1, 2, 3 mm) and number of electrode windings(7, 9, 11) were measured. Experimental results showed that for the frequency of 10 kHz, the highest decomposition efficiency of 94.3 % for NO and 84.7 % for $NO_{2}$ were observed at the power consumptions of 19.8 and 20W respectively and that decomposition efficiency decreased with increasing frequency above 20 kHz. Decomposition efficiency was increased with increasing residence times and with decreasing initial concentration of pollutants. Decomposition efficiency was increased with increasing thickness of discharge electrode and the highest decomposition efficiency was obtained for the electrode diameter of 3 mm in this experiment. As the electrode material, decomposition efficiency was in order : tungsten(W), copper(Cu), aluminum(Al).

• Korean Journal of Materials Research
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• v.14 no.8
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• pp.552-557
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• 2004

Thin Ni-B films, 1 ${\mu}m$ thick, were electrolessly deposited on Cu bus electrode fabricated by electro deposition. The purpose of these films is to encapsulate Cu electrodes for preventing Cu oxidation and to serve as a diffusion barrier against copper contamination of dielectric layer in AC-plasma display panel. The layers were heat treated at $580^{\circ}C$(baking temperature of dielectric layer) with and without pre-annealing at $300^{\circ}C$($Ni_{3}B$ formation temperature) for 30 minutes. In the layer with pre-annealing, amount of Cu diffusion was lower about 5 times than that in the layer without pre-annealing. The difference of Cu concentration could be attributed to Cu diffusion before $Ni_{3}B$ formation at grain boundaries. However, the diffusion behavior of the layer with pre-annealing was similar to that of the layer without pre-annealing after $Ni_{3}B$ formation. With increasing annealing time, Cu concentration of both layers increased due to grain growth.

• Journal of Powder Materials
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• v.16 no.6
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• pp.389-395
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• 2009

A Si-CuO-graphite composite was prepared by a mechanical alloying (MA) method. The Si-CuO composite has a mixture structure, where CuO is homogeneously dispersed in Si. Also, $Cu_2O$ and $Cu_3Si$ phases were formed during MA and heat treatment. Graphite with the Si-CuO composite was mixed in the same mill for 30 minutes with weight ratio of Si-CuO composite and graphite as 1:1. The Si-CuO composite was homogeneously covered with graphite. SiC phase was not formed. Electrochemical tests of the composite have been investigated, and the first charge and discharge capacities of the material were about 870mAh/g and 660mAh/g, respectively. Those values are about 76% of the first cycle efficiency. The cycle life of the composite showed that the initial discharge capacity of 660 mAh/g could be maintained up to 92% after 20 cycles.

• Journal of Electrochemical Science and Technology
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• v.4 no.4
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• pp.140-145
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• 2013

This study describes the electrodeposition of $Cu_2Se$ thin films with a two-step approach that is based on the initial modification of polycrystalline Au electrode with a selenium overlayer followed by a cathodic stripping of the layer as $Se^{2-}$ in a 1 M lactic acid electrolyte containing $Cu^{2+}$ ions. For this two-step approach to be effective, the $Cu^{2+}$ reduction potential should be shifted to more negative potentials passed potentials for the reduction of Se to $Se^{2-}$. This was accomplished by the complexation of $Cu^{2+}$ ions with lactic acid. The resultant $Cu_2Se$ films were characterized by linear sweep voltammetry combined with electrochemical quartz crystal microgravimetry, UV-vis absorption spectrometry and Raman spectroscopy. Photoelectrochemical experiments revealed that $Cu_2Se$ synthesized thus, behaved as a p-type semiconductor.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.618-618
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• 2013

Graphene is only one atom thick planar sheet of sp2-bonded carbon atoms arranged in a honeycomb crystal lattice, which has flexible and transparent characteristics with extremely high mobility. These noteworthy properties of graphene have given various applicable opportunities as electrode and/or channel for various flexible devices via suitable physical and chemical modifications. In this work, for the development of all-graphene devices, we performed to synthesize alternately patterned structure of mono- and multi-layer graphene by using the patterned Ni film on Cu foil, having much different carbon solid solubilities. Depending on the process temperature, Ni film thickness, introducing occasion of methane and gas ratio of CH4/H2, the thickness and width of the multi-layer graphene were considerably changed, while the formation of monolayer graphene on just Cu foil was not seriously influenced. Based on the alternately patterned structure of mono- and multi-layer graphene as a channel and electrode, respectively, the flexible TFT (thin film transistor) on SiO2/Si substrate was fabricated by simple transfer and O2 plasma etching process, and the I-V characteristics were measured. As comparing the change of resistance for bending radius and the stability for a various number of repeated bending, we could confirm that multi-layer graphene electrode is better than Au/Ti electrode for flexible applications.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1713-1715
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• 1996

The $NO_2$ GAS Sensitivity characteristic of CuTBP(Copper-tetra-tert-butylphthalocyanine) LB films were investigated through a study of current-voltage (I-V) characteristics with a variation of number of electrode finger pairs N ($1{\sim}25$). A concentration of 200ppm $NO_2$ gas was used. It was found that a conductance G increases monotonically as the number of interdigital electrode increases, and a Sensitivity, Reproducibility is stable. As far as a current is concerned, the current when N=25 is greater than that when N=1 by 70 or so. It indicates that the number of interdigital electrodes affects the current, sensitivity and stability. We knew that the $NO_2$ gas detector application possibility using a current of N=25.

• Journal of Electrochemical Science and Technology
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• v.2 no.1
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• pp.8-13
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• 2011

Interfacial compatibility between the Si-Cu electrode and diluted ionic liquid electrolyte containing 50 vol.% of 1M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)/1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide (MPP-TFSI) and 50 vol.% dimethyl carbonate (DMC) in a lithium cell and dilution effect on surface chemistry are examined. ex-situ ATR FTIR analysis results reveal that the surface of the Si-Cu electrode cycled in the diluted ionic liquid electrolyte is effectively passivated with the SEI layer mainly composed of carboxylate salts-containing polymeric compounds produced by the decomposition of DMC. Surface species by the decomposition of TFSI anion and MPP cation are found to be relatively in a very low concentration level. Passivation of electrode surface with the SEI species contributes to protect from further interfacial reactions and to preserve the electrode structure over 200 cycles, delivering discharge capacity of > 1670 $mAhg^{-1}$ and capacity retention of 88% of maximum discharge capacity.

• Journal of the Korean institute of surface engineering
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• v.49 no.3
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• pp.252-259
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• 2016

In order to form an aluminum-doped zinc oxide (AZO) transparent electrode film on a polyethylene terephthalate (PET) substrate used for a flexible display substrate, the AZO transparent electrode was produced at low temperature without substrate heating. Even though the produced electrode showed characteristic optical transmittance of 90 % (at 550 nm) and sheet resistance within $100{\Omega}/sq$, cracks occurred 10 minutes after loading applied 2 mm radius of curvature, and the sheet resistance increased linearly. An insertion layer of ZrCu was formed between the AZO film and the PET substrate to suppress the generation of cracks on the AZO film. It was verified that the crack was not generated 30 minutes after the loading of 2 mm radius of curvature, and no increase in sheet resistance was recorded. There was also not cracks in the dynamic bending test of 4 mm radius, but surface resistance was slightly increased. As a result, the ZrCu insertion film improved the interfacial adhesion between the substrate and AZO film layer without increasing sheet resistance and decreasing transmittance.