• 대한화학회지
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• 제28권4호
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• pp.238-243
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• 1984

Molybdate 이온 감응에 대하여 세가지 성분인 $Ag_2S-PbS-PbMoO_4$로된 전극이 제조되어 평가되었다. 성분비(w/w%)가 64.5 : 14.0 : 21.5인 전극이 전위차 감응, 안정도, 감응속도, 재현성이 우수 하였다. 0.1F $NH_4Ac-NH_4OH$ 완충용액 속에서 일정한 이온강도와 pH 7.95로 조정된 $10^{-1} {\sim} 10^{-5}M\;MoO_4^{2- }$농도범위에서 실험하였고, $I^-,\;Cl^-,\;Br^-$ 와 $CN^-$등이 방해하였다.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2002년도 전지기술심포지움
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• pp.57-65
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• 2002

The presence of tetragonal phase at the surface of $LiMn_2O_4$ pinicle due to a Jahn-Teller offset was previously reported to be one of the causes for capacity fading observed during cycling of $Li//Li_xMn_2O_4$ in 4V range. Further, it is reported that a Jahn-Teller effect in 4V range may be suppressed by substitution of Mn ions with Li ions or other transition metal ions. However, the direct evidence of the suppression of a Jahn-Teller effect in 4V range by substitution of Mn ions with other metal ions has not been reported. The dissolution and formation of surface film at the surface of $LiMn_2O_4$ electrodes also reportedly affect the capacity fading or rate capability. This study reports on the evidence of the onset and suppression of a Jahn-Teller effect in 4V range and the dissolution and formation of surface film at the surface of $LiMn_2O_4$ thin film electrodes using in situ bending beam method (BBM) in situ electrochemical quartz crystal microbalance (EQCM).

• 대한기계학회논문집A
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• 제31권10호
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• pp.981-985
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• 2007

We present a MEMS-based portable Direct Methanol Fuel Cell (micro-DFMC), featured by a platinum sputtered microcolumn electrode and a built-in fuel chamber containing a limited amount of methanol fuel. Also presented is a micro-DMFC stack structure having a common electrolyte sandwiched by the microcolumn electrodes. The single cells with ME16 and PE16 electrodes show the maximum power densities of $31.04{\pm}0.29{\mu}W/cm^2$ and $9.75{\pm}0.29{\mu}W/cm^2$, respectively; thus indicating the microcolumn electrode (ME16) generates the power density (3.2 times) higher than the planar electrode (PE16). The single cell tests of ME16 and ME4 electrodes (Fig.8) show the maximum power of $31.04{\pm}0.29{\mu}W/cm^2$, and $25.23{\pm}2.7{\mu}W/cm^2$, respectively; thus demonstrating the increased window frame reduces the normalized standard power deviation (standard deviation over the average power). The normalized deviation of 0.11 in ME4 cell has been reduced to 0.01 in ME16 cell due to the increased window frames. The maximum power density of 4-cell stack is 15.7 times higher than that of the single cell. 4-cell stack produces the power capacity of 20.3mWh/g during 980min operation at the voltage of 450mV with the load resistance of $800{\Omega}$.

• Journal of Electrochemical Science and Technology
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• 제6권4호
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• pp.139-145
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• 2015

Capacitive deionization (CDI) process is a novel approach for desalination of an aqueous salt solution. In the present study, an activated carbon cloth (ACC) is proposed as effective electrode material. Initially the carbon cloth was activated in 1 M and 8 M HNO₃ for 9 hours at room temperature. The untreated and chemically activated carbon cloth (ACC) electrode materials were subjected to BET surface area measurements in order to get information about their specific surface area, average pore size, total pore volume and micropore area. The above materials were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) also. The electrochemical studies for the electrodes were done using cyclic voltammetry (CV) in 0.1 M Na₂SO₄ medium. From the studies, it was found that resistivity of the activated carbon cloth electrodes (treated in 1 M and 8 M HNO₃) was decreased significantly by the chemical oxidation in nitric acid at room temperature and its capacitance was found to be 90 F/g (1 M HNO₃) and 154 F/g (8 M HNO₃) respectively in 0.1 M Na₂SO₄ solution. The capacitive deionization behavior of a single cell CDI with activated carbon cloth electrodes was also studied and reported in this work.

• 전기화학회지
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• 제10권1호
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• pp.1-6
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• 2007

금 나노 입자를 회합시킨 흑연전극 표면에 mercaptopropionic acid(mpa)를 사용하여 자기조립 단층막(self-assembled monolayer: SAMs)을 생성시키고 이어서 도파민(dopa)과의 짝지움 반응을 통하여 Gr(Au)/mpa-dopa형의 수식된 전극을 제작하여 NADH의 전기촉매 산화반응에 적용하였다. 이 수식 전극이 전자전달반응속도와 반응과정에 대하여 연구하였다. 전극 표면에 고정된 도파민이 NADH와 이차반응 속도상수는 회전 전극법으로 0.1 M 인산염 완충용액(pH=7.0)에서 결정하였으며 그 값이 $5.06{\times}10^5M^{-1}s^{-1}$였고, $EC_{cat}$ 및 전자전달이 지배적인 과정이었다. 그러나 반응초기 즉, $10^{-3}s$ 이내에서는 이 전극에서 확산에 영향을 받으며 그 때 확산계수는 $4.64{\times}10^{-4}cm^2s^{-1}$이다.

• 전기화학회지
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• 제7권1호
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• pp.16-20
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• 2004

플러렌 이온$(full^-)$으로 수식된 피를 고분자 피막을 전기화학법으로 중합하기 위하여 사용된 전지는 Au/5mM pyrrole, 1mM fullerene, 0.1M $TBABF_4,\; CH_2C1_2/Pt$이었으며 이 전지로 $electrode/ppy(full^-)ppy(full^-){\ldots}$와 같은 웨이퍼형의 전극을 제작하였다. 이 전극을 사용한 Au(quartz crystal analyzer; QCA)/ppy$(full^-)$, 0.01M metal ion(aq.)/Pt형의 전지로 알카리 금속이온을 포집하였다. $Li^+,\;Na^+,\;K^+,\;Rb^+$ 및 $Cs^+$이온의 포집에 대한 속도상수는 일차반응 속도식으로 계산한 결과 그 값이 각각 $1.60\times10^{-8},\;3.13\times10^{-11},\;1.38\times10^{-9},\;2.71\times10^{-11}$ 및 $2.98\times10^{-12}mo1.s^{-1}$이였다. 이 전극을 수정판 미량저울(QCM)을 적용하여 결정한 각 이온의 화학양론은 $Li_7C_{60},\;Na_4C_{60},\;K_3C_{60},\;Rb_1C_{60}$ 및 $Cs_1C_{60}$이었다.

• Bulletin of the Korean Chemical Society
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• 제34권3호
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• pp.851-855
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• 2013

This paper describes an environmentally friendly process for the recovery of $LiFePO_4$ cathode materials from scrap electrodes by a simple thermal treatment method. The active materials were easily separated from the aluminum substrate foil and polymeric binders were also decomposed at different temperatures ($400^{\circ}C$, $500^{\circ}C$, $600^{\circ}C$) for 30 min under nitrogen gas flow. The samples were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), Raman spectroscopy, Thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The electrochemical properties of the recycled $LiFePO_4$ cathode were evaluated by galvanostatic charge and discharge modes. The specific charge/discharge capacities of the recycled $LiFePO_4$ cathode were similar to those of the original $LiFePO_4$ cathode. The $LiFePO_4$ cathode material recovered at $500^{\circ}C$ exhibits a somewhat higher capacity than those of other recovered materials at high current rates. The recycled $LiFePO_4$ cathode also showed a good cycling performance.

• 전기화학회지
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• 제17권2호
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• pp.103-110
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• 2014

본 연구에서는 리튬 이차 전지의 가연성이 높은 액체 전해액의 대체 또는 개선을 위하여 이온성 액체 전해액으로 전극들에서의 거동을 관찰하였다. 이온성 액체인 1-ethyl-1-methyl piperidinium bis(trifluoromethanesulfonyl)imide(PP12 TFSI)는 녹는점이 $85^{\circ}C$이므로 상온에서 고체상이다. PP12 TFSI를 단독으로 전해액에 사용할 수 없으므로 리튬 이온 전지용 용매와 혼합하여 사용한다. PP12 TFSI를 50 wt.% 이상 사용하면 난연성이 아주 좋은 반면에 점도가 높아서 전해액 함침이 어렵다. 이온성 액체의 비율을 44 wt.%(이온성 액체:용매=1:1.25 wt.%)로 맞추고, 혼합한 용매는 EC/DEC(1/1 vol.%)이며, $LiPF_6$의 농도가 1.5 M이 되도록 전해액을 준비하여 연구하였다. 준비한 전해액은 자가소화시간 25초의 준수한 난연성을 가지고 있으며, 여러 종류의 전극에서도 우수한 수명 성능을 보여주었다. 적용된 전극은 $LiNi_{0.5}Mn_{1.5}O_4(LNMO)$, $LiFePO_4(LFP)$, $Li_4Ti_5O_{12}(LTO)$, artificial graphite이며, 특히 음극으로 사용된 artificial graphite에서의 전해액 분해를 방지하기 위한 첨가제의 거동도 관찰하였다. 여전히 전극으로의 함침의 문제가 다소 관찰이 되었으며 이런 문제가 개선될 수 있는 최적화된 혼합 이온성 액체 전해액이 개발된다면 이온성 액체의 난연성 특성은 더욱 활용성이 높아질 것이다.

• Journal of Electrochemical Science and Technology
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• 제4권2호
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• pp.57-60
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• 2013

Nickel is a good electrocatalytic metal and nickel electrodes find many applications in different electrochemical fields. The nickel plated electrodes were prepared by electro-deposition technique on mild steel surface modified with in-situ deposition of nickel titanate. The SEM images shows that the nickel plating on nickel titanate modified mild steel shows better adherence than the nickel plating on bare mild steel surfaces. The extent of polarization of the nickel plating on mild steel with nickel titanate was lower than that of nickel plating on mild steel. The incorporation of nickel titanate on mild steel surface before nickel plating enhances physical, chemical and electrochemical properties of the plating film.

• 전자공학회논문지A
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• 제30A권7호
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• pp.75-81
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• 1993

In this paper, New type of Static Edge Triggered D Flip-Flop Circuits which are effective for the sequencial selecting and addressing of Matrix type Electrodes being applied to Flat Display Devices is proposed by the Design Technique using the Transmission Characteristics of Feedback Transistors and Charge Back Up Function. These Circuits composed of 2-4 less transistors in number than Conventional Static D Flip Flop's have some advantages that the Maximum Transition Time of Clock Signals allowed is increased by 100-450 times more than that of the Conventional circuit at 100KHz Clock Frequence and Circuit Safety is much increased by making the wider ranges, 1-4V, of Clock Levelas a Non-operating periods than 3-3.2V ranges in case of the Conventional Circuit at 10MHz clock frequence. By these advantages, These circuits can be very effectively used in case that clock signal has long transition time, especially on the low frequency operation.