• Title/Summary/Keyword: 이온 전극

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Electrosorption Behavior of $TiO_2$/Activated Carbon Composite for Capacitive Deionization (축전식 이온제거에 대한 $TiO_2$/Activated Carbon 화합물의 전기흡착 거동)

  • Lee, Jeong-Won;Kim, Hong-Il;Kim, Han-Joo;Park, Soo-Gil
    • Applied Chemistry for Engineering
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    • v.21 no.3
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    • pp.265-271
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    • 2010
  • Desalination effects of capacitive deionization (CDI) process was studied using $TiO_2$/activated carbon electrode. In order to enhance the wettability of electrode and decrease a electrode resistance, $TiO_2$ was coated on activated carbon. By means of $TiO_2$ coating on activated carbon, electric double layer to adsorption content in CDI process was increased. It was identified from TEM, XRD, and XPS that the activated carbon based on $TiO_2$ composite was fabricated successfully by means of sol-gel method. As a results of cyclic voltammetry and impedance, it was identified that $TiO_2$/activated carbon electrode has more electric double later capacitance and less diffusion resistance than activated carbon. Also charge-discharge and ion conductivity profiles showed that the ion removal ratios of $TiO_2$/activated carbon electrode in NaCl electrolyte of $1000\;{\mu}S/cm$ more increased about 39% than that of activated carbon. In conclusion it was possible to identify that the carbon electrode coated $TiO_2$ as electrode material was more effective than raw carbon electrode.

Effect of Electrode Design on Electrochemical Performance of Highly Loaded LiCoO2 Positive Electrode in Lithium-ion Batteries (리튬이온 이차전지용 고로딩 LiCoO2 양극의 전극설계에 따른 전기화학적 성능연구)

  • Kim, Haebeen;Ryu, Ji Heon
    • Journal of the Korean Electrochemical Society
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    • v.23 no.2
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    • pp.47-55
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    • 2020
  • Highly loaded LiCoO2 positive electrodes are prepared to construct high-energy density lithium-ion batteries, their electrochemical performances are evaluated. For the standard electrode, a loading of about 2.2 mAh/㎠ is used, and for a high-loading electrode, an electrode is manufactured with a loading level of about 4.4 mAh/㎠. The content of carbon black as electronic conducting additive, and the porosity of the electrode are configured differently to compare the effects of electron conduction and ionic conduction in the highly loaded LiCoO2 electrode. It is expected that the electrochemical performance is improved as the amount of the carbon black increases, but the specific capacity of the LiCoO2 electrode containing 7.5 weight% carbon black is rather reduced. When the conductive material is excessively provided, an increase of electrode thickness by the low content of the LiCoO2 active material in the same loading level of the electrode is predicted as a cause of polarization growth. When the electrode porosity increases, the path of ionic transport can be extended, but the electron conduction within the electrode is disadvantageous because the contact between the active material and the carbon black particles decreases. As the electrode porosity is lowered through the sufficient calendaring of the electrode, the electrochemical performance is improved because of the better contact between particles in the electrode and the reduced electrode thickness. In the electrode design for the high-loading, it is very important to construct the path of electron conduction as well as the ion transfer and to reduce the electrode thickness.

Effect of the Surface Electrode Formation Method and the Thickness of Membrane on Driving of Ionic Polymer Metal Composites (IPMCs) (표면전극 형성 방법과 이온-교환막 두께가 이온성 고분자-금속 복합체(IPMC) 구동에 미치는 영향)

  • Cha, Gook-Chan;Song, Jeom-Sik;Lee, Suk-Min;Mun, Mu-Seong
    • Polymer(Korea)
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    • v.30 no.6
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    • pp.471-477
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    • 2006
  • Ion exchange metal composite(IPMC) has toughness equivalent to the range of human's muscle, transformation-actuation force by relatively low voltage and the fast response time. Thus, as a new method for preparing thicker IPMC, the solution casting method to make the films of various thicknesses out of liquid nation was attempted in this study. To reduce the surface resistance of electrode, the first plated electrode prepared by Oguro method was replated with Au and Ir using ion beam assisted deposition(IBAD). The microstructures of electrode surfaces before and after IBAD plating were investigated using SEM. The change of water and ion-conductivity in IPMC were measured under applied voltage. The displacement and driving force of IPMCs with various thicknesses were measured to evaluate the driving properties.

Gas-Sensing Membrane Electrodes for the Determination of Dissolved Gases (Ⅳ). Continuous-Automated Determination of Sulfide Ion Using Tubular PVC Membrane Type pH Electrode (용해기체 분석용 기체감응막 이온선택성 전극 (제 4 보) 관형 PVC막 pH전극을 이용한 황화이온의 연속 · 자동화 정량)

  • Lee Heung Lark;Bae Zun Ung;Oh Sang-Hyub
    • Journal of the Korean Chemical Society
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    • v.36 no.5
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    • pp.638-643
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    • 1992
  • The analytical response properties of two types of continuous flow-through electrode system as fulfide ion detectors are examined and directly compared their reponse characteristics under the optimal conditions. In both detection systems, observed peak potentials are logarithmically related to the sulfide ion concentration and at least twenty samples per hour can be determined. In the pH electrode method, the pH of the flowing recipient stream leaving the dialyzer was monitored. The designed system involves the use of continuous flow gas dialyzer in conjunction with the tubular polymer membrane electrode. In this method, optimal experimental conditions are recipient of mixture of $5.0 {\times} 10^{-5} M NaOH + 5.0 {\times} 10^{-3} M$ NaCl and diluent of 0.10 M $H_2SO_4$, and all flow rates of recipient stream, diluent stream, and sample are 1.0 ml/min. In the sulfide ion electrode method, a commercially available sulfide ion-selective electrode was used to detect sulfide ion in the flow-through cell. The optimal flow rates of sulfide anti-oxidant buffer (3.5 g ascorbic acid and 7.6 g $Na_2EDTA$ dissolved in 1.0 M NaOH solution 1 l) and sample were 1.4 ml/min and 1.0 ml/min, respectively.

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고밀집 섬유집합체에 의해 유도된 모세관현상을 이용한 순환식 수은전극 전해계의 개발과 그 특성 연구

  • 김광욱;변기호;이일희;유재형;박현수
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.05c
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    • pp.565-570
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    • 1996
  • 본 연구에서는 고밀집 섬유다발체 내에 수은과 금속이온을 함유한 수용액을 동시에 주입시켜 최소 공간에서 최대한의 수은전극 면적을 갖는 수직형 순환식 수은 모세관 다발체 전극 전해반응 장치가 개발되었다. 이장치의 특성과 안정성을 평가하기 위해 수은과 수용액의 유량 변화에 따른 철(III)과 우라늄(IV)이온의 환원 voltammogram 이 측정되었다. 본 연구에서 개발된 수직형 순환식 수은 모세관 다발체 전극 전해계는 정확히 제어되는 수용액 유량조건에서 수용액내의 금속이온의 산화수 상태 및 농도의 연속적인 분석 및 전해반응 기구 해석에 효과적으로 사용될 수 있음을 알 수 있었다.

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Differential Pulse Voltammetric Determination of Iron(II) ion with a Nafion-Ethylenediamine Modified Glassy Carbon Electrode (Nafion-ethylenediamine이 수식된 유리탄소전극에 의한 시차펄스전압전류법으로 철(II) 이온의 정량)

  • Kyong Wone Kim;Hee Cheol Kim;Sung-Hyun Kim;Byung Ho Park;Yeon Hee Kim;Kyong Nam Kim;Yong Chun Ko
    • Journal of the Korean Chemical Society
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    • v.47 no.2
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    • pp.115-120
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    • 2003
  • Determination of iron(II) ion with a perfluorinated sulfonated polymer(nafion)-ethylenediamine(en) modified glassy carbon electrode was studied. It was based on the chemical reactivity of an immobilized layer(nafion-en) to yield complex $[Fe(en)_3]^{+2}$. The oxidation peak potential by differential pulse voltammetry(DPV) was observed at 0.340${\pm}$0.015 V(vs. Ag/AgCl). The linear calibration curve was obtained in iron(II) ion concentration range $5{\times}10^{-6}{\sim}0.2{\times}10^{-3} M(0.28{\sim}11.17\; mg/L)$, and the detection limit(3s) was $1.89{\times}10^{-5}$M(1.056 mg/L).

Correcting Errors Associated with Blood Urea Measurements Employing Nonaction-Doped Ammonium-Selective Electrodes (암모늄선택성 전극을 이용한 요소센서의 오차보정에 관한 연구)

  • Kim, Young No;Shin, Doo Soon;Kim, Chang Yong;Shin, Jae Ho;Nam, Hakhyun;Cha, Geun Sig
    • Journal of the Korean Chemical Society
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    • v.39 no.12
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    • pp.925-931
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    • 1995
  • Urea sensors, prepared by immobilizing urease on ammonium-selective membrane electrodes doped with nonactin, can show interference from several ionic species present in blood samples (e.g., sodium, potassium, and endogenous ammonium ions). This interference problem does not arise from the immobilized biocatalytic reaction but rather from the innate response of the base transducer to ionic species in the sample. In this work, the use of calibrators containing adequate amounts of ionic species is examined to reduce errors caused by endogenous ionic interferences with blood urea measurements. Simultaneous measurements of the interfering species with additional sensors and subsequent substractions of these values from the urea electrode signals are also described. It is shown that the use of a potassium-selective electrode with an adequate calibrator system greatly enhances the accuracy of the urea sensor measurements.

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Tallium(I) Ion-Selective Electrodes Based on Crown Ethers (크라온에테르를 이용한 탈륨(I) 이온 선택성 전극)

  • Sung Min Kim;Sung Uk Jung;Jineun Kim;Jae Sang Kim
    • Journal of the Korean Chemical Society
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    • v.37 no.8
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    • pp.773-778
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    • 1993
  • Poly(vinyl chloride)(PVC) membrane electrodes based on the lipophilic neutral carrier, dibenzo-18-crown-6(DB18C6) and benzo-15-crown-5 (B15C5) as the active sensors for Tl$^+$ ion have been prepared and tested in different content of the potassium tetrakis(4-chlorophenyl)borate (KTClPB) as lipophilic salt. Dioctyl adipate (DOA), 2-nitrophenyl phenyl ether (NPPE) and o-nitrophenyl actyl ether (NPOE) were used as plasticizing solvent mediators. Electrodes exhibited good linear responses of 40∼55 mV decade$^{-1}$ for Tl$^+$ ion within the concentration ranges 10$^{-1}$∼10$^{-5}$M TlNO$_3$. Selectivity coefficients of interfering ions (alkali metal, alkaline earth metal and some transition metal ions) for Tl$^+$-ISE were determined by separate solution method and were sufficiently small for most of them. These crown ether type ion-selective electrodes are suitable for use with aqueous solution at pH > 3.

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Electrochemical Reduction of Perchlorate Using Mercury Film Electrode (수은 막전극을 이용한 수용액 중 과염소산이온의 전기화학적 환원)

  • Myung, Noseung;Kim, Eun Young;Jee, Hyung-Woo;Keum, Narae;Rhee, Insook;Paeng, Ki-Jung
    • Journal of the Korean Electrochemical Society
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    • v.19 no.3
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    • pp.95-100
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    • 2016
  • A method for electrochemical degradation of the perchlorate anion ($ClO_4{^-}$) using mercury film electrode has been studied. Electrochemical method has relatively simple pre-treatment. However, electrochemical method should avoid interference from hydrogen evolution at the applied potential to degradation of perchlorate ion, and thus applied electrode should have large hydrogen overvoltage which suppressed the hydrogen evolution at the working reduction potential to prevent hydrogen evolution. In this study, we used mercury film electrode as a working electrode which has a large overvoltage. Ag / AgCl (sat. NaCl) was used as a reference electrode, and platinum was used as a counter electrode. Mercury film electrode was made by cyclic voltammetry (CV) method. The deposition time was decided as 10 minute, and the stability of the mercury electrode in perchlorate solution was confirmed by CV. The reduction potential of perchlorate was checked by using CV method, and decomposition of perchlorate was performed by using chronoamperometric (CA) method. Also, ion chromatography (IC) was used to confirm the degradation rates of perchlorate.

Current of planar switch during the recovering time of the negative pulse (음펄스 전압회복에 따른 평판형 스위치 전극에 흐르는 전류의 거동 관찰)

  • Hwang, Hui-Dong;Choe, James;Ko, Kwang-Cheol;Kim, Gon-Ho
    • Proceedings of the KIEE Conference
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    • 2004.11a
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    • pp.120-122
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    • 2004
  • 평판 스위치 전극에 인가되는 전압 변화에 따라서 전극 앞에서의 플라즈마 전위의 변화를 측정하고, 이를 이용하여 형성된 전계의 변화를 관찰하였다. 대부분 스위치 전각에 인가되는 펄스는 펄스 인가시간, 플래토(plateau)시간, 펄스 회복시간으로 구성되어 이들 세 가지 시간 구간에 따라서 전위의 변화를 측정하여 형성되는 전계를 관찰하였다. 빠른 방전 스위치의 동작특성을 이해하기 위하여 스위치 전극인가 전압의 인가시간 변화와 이에 따른 전압 변화율 및 인가전압의 크기에 따른 플라즈마 쉬스의 거동을 관찰하고, 그 크기가 펄스 변화율과 크기에 따라 변화함을 찾았다. 펄스의 회복시간 동안에 돌아오는 플라즈마 쉬스의 거동은 펄스의 인가시간동안의 변화와 유사한 거동을 보였으며 이때에도 펄스 회복율이 중요한 인자임을 알 수 있었다. 만일 펄스 변화율이 커서, 전극 앞에서의 쉬스의 거동 속도가 플라즈마 이온의 음속보다 빠르게 변할 때는 이온 매트릭스 쉬스의 거동형태를 따르고, 변화율이 늦어서 쉬스의 거동 속도가 이온의 음속보다 느리게 변하는 경우에는 Child-Langmuir 쉬스의 형태가 시간에 따라 전개됨을 알 수 있었다. 펄스 특성을 정량적으로 관찰할 수 있도록 스위치 전극에 흐르는 전류의 크기를 계산하기 위해 필요한 모델을 개발하여 실험견과와의 비교를 통하여 펄스 시간동안 플라즈마의 거동이 스위치를 흐르는 전류에 미치는 영향을 연구하였다.

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