• Journal of the Korean Electrochemical Society
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• v.6 no.2
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• pp.153-157
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• 2003

A hybrid electrochemical capacitor having both characteristics of electric double layer capacitance and pseudo-capacitance was studied throughout cell tests. Asymmetric electrodes with $Ni(OH)_2/activated$ carbon based positive electrode and activated carbon based negative electrode were used in preparing test cells of $5\times5cm^2$. Cyclic voltammetry measurements and impedance measurements were conducted to understand electrochemical behavior of each electrode. To find an optimal mass ratio of negative to positive electrode, charge-discharge cycle tests were also performed.

• Transactions on Electrical and Electronic Materials
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• v.8 no.2
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• pp.97-102
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• 2007

The charging/discharging characteristics of electric double layer capacitors (EDLCs) for an electric power storage device application were investigated. The specific area of the carbonaceous electrode surface by the BET method was in the range of $1800{\sim}2000\;m^2/g$. The charge distributions during charging and discharging were measured by means of a pulsed-electro-acoustic (PEA) method, and the voltage characteristics of EDLCs connected to solar cells were evaluated. The results showed that the distributions of positive and negative charges were spatially uneven, which was due to the mobility of the positive and negative charges in the carbonaceous electrode surface of the EDLCs. The charge accumulation region concentrated on central part of the carbonaceous electrode and the required times for charging and discharging were almost same.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.140-144
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• 2003

To investigate failure analysis of surface acoustic wave (SAW) filter for radio frequency, high temperature storage test was carried out. The failure criteria were insertion loss at passband and rejection level at stopband. As a result, the insertion loss at passband increase about 4 dB was due to damages of interdigital transducer (IDT). That is caused by poor adhesion between metal electrode(AI) and piezoelectric substrate and defects on a manufacturing process. This result indicates that good adhesion between electrode and ceramic substrate is important factor And also we investigated the demage factors of electrode. Screen possible of saw filter using high temperature storage test(HTOL) in the manufacturing phase be presented.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.3
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• pp.317-323
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• 2006

Electric conductive material should be homogeneously mixed with sulfur in sulfur electrode fabrication of lithium/sulfur battery, because sulfur is electric insulator. In this paper electrochemical properties of Li/S battery was studied with various compositions of sulfur electrodes. When content of sulfur changed from 40 wt.% to 80 wt.%, the 60 wt.% sulfur electrode showed the maximum capacity of 1489 mAh/g-sulfur. Electrochemical properties of Li/S battery using 60 wt.% sulfur was also investigated with various carbon contents. The discharge capacity changed as a function of carbon contents. The optimum composition was 25 wt.% carbon for 60 wt.% sulfur electrode.

• Journal of the Korean Electrochemical Society
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• v.13 no.3
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• pp.157-162
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• 2010

The electrodes comprising nano-sized $LiFePO_4$, carbon black and binder are prepared with two different Al current collectors. One is the generally used normal Al foil and the other is the chemically etched Al foil. Surface characteristics of each Al foil and electrochemical performance of the cathodes using each foil are investigated. The electrode from the etched Al foil exhibits better physical and electrochemical properties as compared to those of the normal Al foil because the etched Al foil has rough surface with sub-micron pores which improve the adhesion between the electrode materials and the substrate. The electrode on the etched Al foil has such a strong peel strength that the impedance is smaller than that of normal one. Indeed the $LiFePO_4$ electrode from the etched Al foil exhibits a better rate capability and remains intact even after storage for 1 week at the charged state at the elevated temperature $60^{\circ}C$.

• Journal of the Korean institute of surface engineering
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• v.30 no.4
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• pp.262-271
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• 1997

Nickel-matal hydride(Ni-MH) batteries are receiving attention as non-pollunting. high performance rehargeable energy stoage system. The performance of Ni-Mh is significantly influenced by the hydrogen storage alloy materiels used as an anode material. Recently, having discharge capacities higher than the $AB_5$-type hydrogen storage alloys, the Zr-based $AB_2$-Type hydrogen storage alloys has remaining problems regarding cycle life and self-dischareg. These problems need to be solved by improvements in the alloy design and/or surface treatment. This work investiggates the effects the effects of surface property by fluorination on $Zr_{0.7}Ti_{0.3}V_{0.4}Mn_{0.4}Ni{1.2}$ composittion $AB_2$-Type hydrogen storage alloys. EPMA, SEM and AES techniques were used for surface analysis, and the crystal structure was characterized by constant current cycling test and potential sweep methods. Fluorination was found to be effective when La-was incorporated into the alloy, and has unique morphology, higher reactivity, and at the same time formed a protective film. Through, fluorination, the cycle life of an electrode was found to increase significantly, charge/discharge characteristics of the electrode the potential difference between the charge/discharge plateau, i.e polarization(overpotential)were improved.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.208-210
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• 2008

We have developed a LCD Panel that form storage capacitance for pixels between pixel electrode of bottom glass and common electrode of top glass. This method could make higher transmission and higher production yield than before by removing storage electrode line and capacitance on the bottom glass by simplifying bottom pixel structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.539-540
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• 2006

In this paper, We examine that characteristics of formative electret with polymer film and electric charge storage using grid corona discharge. compound polymer of fluorine resin used for material in electret because of high electric charge accumulation, excellent electrical and physical characteristic. All experiments were carried out with circular samples of $Teflon^(R)FEP$ film, 12.5[${\mu}m$] thick. As experiment variables, we used voltage, electrode thickness, discharge electrode gap, and discharge time. According to this variables, we studied on characteristics of formative electret and electric charge storage. Additionally we make a comparative study of the result between the grid corona discharge and needle electrode discharge.

• Korean Journal of Materials Research
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• v.29 no.8
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• pp.505-510
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• 2019

Zn-ion supercapacitors (ZICs) show high energy densities with long cycling life for use in electronic devices. Porous Zn electrodes as anodes for ZICs are fabricated by chemical etching process using optimized conditions. The structures, morphologies, chemical bonding states, porous structure, and electrochemical behavior are examined. The optimized porous Zn electrode shows a root mean square of roughness of 173 nm and high surface area of $153{\mu}m^2$. As a result, ZIC using the optimized porous Zn electrode presents excellent electrochemical performance with high specific capacitance of $399F\;g^{-1}$ at current density of $0.5A\;g^{-1}$, high-rate performance ($79F\;g^{-1}$ at a current density of $10.0A\;g^{-1}$), and outstanding cycling stability (99 % after 1,500 cycles). The development of energy storage performance using synergistic effects of high roughness and high surface area is due to increased electroactive sites by surface functionalization of Zn electrode. Thus, our strategy will lead to a rational design and contribute to next-generation supercapacitors in the near future.

• Journal of the Korean Ceramic Society
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• v.55 no.5
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• pp.407-418
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• 2018

Increasing demand for portable and wireless electronic devices with high power and energy densities has inspired global research to investigate, in lieu of scarce rare-earth and expensive ruthenium oxide-like materials, abundant, cheap, easily producible, and chemically stable electrode materials. Several potential electrode materials, including carbon-based materials, metal oxides, metal chalcogenides, layered metal double hydroxides, metal nitrides, metal phosphides, and metal chlorides with above requirements, have been effectively and efficiently applied in electrochemical supercapacitor energy storage devices. The synthesis of self-grown, or in-situ, nanostructured electrode materials using chemical processes is well-known, wherein the base material itself produces the required phase of the product with a unique morphology, high surface area, and moderate electrical conductivity. This comprehensive review provides in-depth information on the use of self-grown electrode materials of different morphologies in electrochemical supercapacitor applications. The present limitations and future prospects, from an industrial application perspectives, of self-grown electrode materials in enhancing energy storage capacity are briefly elaborated.