• Title/Summary/Keyword: Cathode electrode

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Simultaneous Determination of Glucose and Ethanol of Takju by Biosensor using Dual Cathode Electrode (Dual Cathode Electrode를 이용한 바이오센서로 탁주 중의 포도당 및 에탄올의 동시 측정)

  • Park, In-Seon;Kim, Jung-Ho;Kim, Tae-Jin;Kim, Nam-Soo;Noh, Bong-Soo
    • Korean Journal of Food Science and Technology
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    • v.28 no.5
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    • pp.974-980
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    • 1996
  • A biosensor was prepared with dual cathode electrode and immobilized enzyme membrane. A nylon net was used for the immobilization of glucose oxidase and alcohol oxidase. The immobilized enzymes were placed on the surface of the electrode which was prepared with one anode and two cathodes as an oxygen electrode. The determination of components by the biosensor was based on the consumption of dissolved oxygen. The optimum condition of this system was 0.1 M potassium phosphate buffer solution, pH 7.5 at $35^{\circ}C$. Glucose and ethanol in takju were simultaneously determined by the biosensor. Comparing with UV-spectrophotometer and gas chromatograph for cross checking, there was a good correlation between the biosensor and the conventional methods. Biosensor with dual cathode electrode required no clarification or pretreatments. It was used for simultaneous determination of glucose and ethanol during the fermentation of takju.

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Cathode Microstructure Control and Performance Improvement for Low Temperature Solid Oxide Fuel Cells (저온 고체산화물 연료전지용 공기극 미세구조 제어 및 성능개선)

  • Kang, Jung-Koo;Kim, Jin-Soo;Yoon, Sung-Pil
    • Journal of the Korean Ceramic Society
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    • v.44 no.12
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    • pp.727-732
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    • 2007
  • In order to fabricate a highly performing cathode for low-temperature type solid oxide fuel cells working at below $700^{\circ}C$, electrode microstructure control and electrode polarization measurement were performed with an electronic conductor, $La_{0.8}Sr_{0.2}MnO_3$ (LSM) and a mixed conductor, $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$(LSCF). For both cathode materials, when $Sm_{0.2}Ce_{0.8}O_2$ (SDC) buffer layer was formed between the cathode and yttria-stabilized zirconia (YSZ) electrolyte, interfacial reaction products were effectively prevented at the high temperature of cathode sintering and the electrode polarization was also reduced. Moreover, cathode polarization was greatly reduced by applying the SDC sol-gel coating on the cathode pore surface, which can increase triple phase boundary from the electrolyte interface to the electrode surface. For the LSCF cathode with the SDC buffer layer and modified by the SDC sol-gel coating on the cathode pore surface, the cathode resistance was as low as 0.11 ${\Omega}{\cdot}cm^2$ measured at $700^{\circ}C$ in air atmosphere.

Electric Conduction Properties of NaCl Electrolyte as a Function of Electrode Materials (전극재료에 따른 NaCl 전해질의 전기전도특성)

  • Kim, Yong-Hyuk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.11
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    • pp.2026-2031
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    • 2010
  • The electrical characteristics of galvanic cell which is composed of the cathode electrode(graphite, carbon and copper) and the anode electrode(Zn and Mg) were investigated. For this research as electrolyte 2~12 wt% NaCl aqueous solution were used. At graphite cathode electrodes which use Zn and Mg with the anode electrode, the open circuit voltage was 1.3V most highly. The maximum output power increased as the electrolyte concentration increased, due to a increase in ion density. When Zn and Mg with the anode electrode, the maximum output power respectively was evaluated as 2.2mW and 5.5mW about the graphite cathode electrode in the NaCl 4wt%. The research results indicated that the output power of cell which is composed with graphite with the cathode and Mg with the anode was most excellent and the efficiency of the cell could be enhanced by increasing the electrolyte concentration.

Effect of Cathode in Electrochemical Reaction for Treating Ballast Water (선박평형수 처리를 위한 전기화학 반응에서 음극의 영향)

  • Kim, Dong Seog;Park, Hye Jin;Yoon, Jong Mun;Park, Yong Seok;Park, Young Seek
    • Journal of Environmental Science International
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    • v.23 no.6
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    • pp.1175-1182
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    • 2014
  • In this study, we examined the effect of cathode from electrolysis reactor for treating ballast water. We are going to select a suitable cathode for seawater electrolysis after considering the effect on the generation of the oxidant of cathode and the electrode deposition materials adhering to the surface of cathode. Anode is Ru-Ti-Pd electrode and cathode are Ti, Pt, JP520 (Ni-Pt-Ce) electrodes. Using the cathode of the three types, experiments were conducted to examine the effects of TRO (total residual oxidants) generation concentration and RNO (N, N-Dimethyl-4-nitrosoaniline, indicator of the generation of OH radical) degradation concentration (in 1, 35 psu), ohmic drop, FESEM(field emission scanning electron microscope) observation of cathode surface and EDX (energy dispersive X-ray spectroscopy) measurements of attached fouling material. The results showed that TRO generation concentration and RNO degradation concentration in according to each type of cathode are not different. The attached fouling materials were observed on the surface of Ti and the JP520 electrode by the observation of SEM after electrolysis for two hours, but it was not observed on the surface of Pt electrode. When considering the surface ohmic drop of cathode and the attached fouling materials, Pt electrode was judged as the excellent cathode.

Evaluation of power density in microbial fuel cells using expanded graphite/carbon nanotube (CNT) composite cathode and CNT anode (팽창흑연·소나노튜브 복합 음극과 탄소나노튜브 양극으로 이루어진 미생물 연료전지의 전력수율 평가)

  • Han, Sun-Kee;Lee, Chae-Young
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.4
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    • pp.503-509
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    • 2013
  • Electrochemical redox capacity of a microbial fuel cell (MFC) electrode is an important factor in the power density. This study was conducted to investigate the redox capacity of surface modified anode and cathode electrodes by measuring their conductivities. An anode electrode was modified with nitric acid and a cathode electrode was modified with heat treatment. The anode electrode modified with 20 % of the nitric acid concentration showed the highest conductivity of $6.2{\mu}S/cm/g$ and the maximum power density of $306.0mW/m^2$ when used in a MFC. The cathode electrode modified at $472^{\circ}C$ for 18 min showed the highest conductivity of $5.2{\mu}S/cm/g$ and the maximum power density of $276.20mW/m^2$ when used in a MFC. On the other hand, an MFC using both the electrodes showed the highest maximum power density of $408.2mW/m^2$. Meanwhile, a control MFC without modified electrodes generated very small voltage (0.014 mV), so the power density could not be measured.

Effect of Electrode Structures on Electron Emission of the $Pb(Zr_{0.56}Ti_{0.44})O_3$ Ferroelectric Cathode ($Pb(Zr_{0.56}Ti_{0.44})O_3$ 강유전체 음극의 전극 모형에 따른 전자 방출 특성)

  • Seo, Min-Su;Hong, Ki-Min
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.4
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    • pp.699-707
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    • 2010
  • Electric-field-induced electron emission from the three kinds of $Pb(Zr_{0.56}Ti_{0.44})O_3$ ferroelectric cathodes with different electrode structure has been investigated. Regardless of the electrode structures, a threshold field of the each cathode was 2.5-2.6kV/mm, which is 3 times higher than the coercive field of $Pb(Zr_{0.56}Ti_{0.44})O_3$ material. Although the waveform of the electron currents was affected by the structure of the electrode, no significant difference for the emission properties such as the peak current and the pulse width was observed from the three kinds of the cathodes. However, the current density of the cathode was dependent on the electrode structure. From the simulation of electric field distribution, the surface flashover, and the injury region of the cathode surface, it was proved that the prime electrons were initiated at the electrode-ceramic-vacuum triple point by field emission and the emission currents were strongly enhanced by the surface plasma.

Enhancement of Electrochemical Performance of Cathode by Optimizing Laccase-Carbon Nanotubes Layers for Enzymatic Fuel Cells (Laccase-탄소나노튜브 적층을 통한 효소 연료전지의 cathode 성능 향상)

  • Wang, Xue;Kim, Chang-Joon
    • 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.

Effect of LiCoO2 Cathode Density and Thickness on Electrochemical Performance of Lithium-Ion Batteries

  • Choi, Jaecheol;Son, Bongki;Ryou, Myung-Hyun;Kim, Sang Hern;Ko, Jang Myoun;Lee, Yong Min
    • Journal of Electrochemical Science and Technology
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    • v.4 no.1
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    • pp.27-33
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    • 2013
  • The consequences of electrode density and thickness for electrochemical performance of lithium-ion cells are investigated using 2032-type coin half cells. While the cathode composition is maintained by 90:5:5 (wt.%) with $LiCoO_2$ active material, Super-P electric conductor and polyvinylidene fluoride polymeric binder, its density and thickness are independently controlled to 20, 35, 50 um and 1.5, 2.0, 2.5, 3.0, 3.5 g $cm^{-3}$, respectively, which are based on commercial lithium-ion battery cathode system. As the cathode thickness is increased in all densities, the rate capability and cycle life of lithium-ion cells become significantly worse. On the other hand, even though the cathode density shows similar behavior, its effect is not as high as the thickness in our experimental range. This trend is also investigated by cross-sectional morphology, porosity and electric conductivity of cathodes with different densities and thicknesses. This work suggests that the electrode density and thickness should be chosen properly and mentioned in detail in any kinds of research works.

In-Situ Analysis of Overpotentials in Direct Methanol Fuel Cell by Using Membrane Electrode Assembly Composed of Three Electrodes (삼전극으로 구성된 막전극접합체를 이용한 직접메탄올 연료전지의 실시간 과전압 분석)

  • Jung, Namgee;Cho, Yoon-Hwan;Cho, Yong-Hun;Sung, Yung-Eun
    • Korean Journal of Materials Research
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    • v.28 no.6
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    • pp.330-336
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    • 2018
  • In this study, a membrane electrode assembly(MEA) composed of three electrodes(anode, cathode, and reference electrode) is designed to investigate the effects of methanol concentration on the overpotentials of anode and cathode in direct methanol fuel cells(DMFCs). Using the three-electrode cell, in-situ analyses of the overpotentials are carried out during direct methanol fuel cell operation. It is demonstrated that the three-electrode cell can work effectively in transient state operating condition as well as in steady-state condition, and the anode and cathode exhibit different overpotential curves depending on the concentration of methanol used as fuel. Therefore, from the real-time separation of the anode and cathode overpotentials, it is possible to more clearly prove the methanol crossover effect, and it is expected that in-situ analysis using the three-electrode cell will provide an opportunity to obtain more diverse results in the area of fuel cell research.

Nurmerical Study on the Discharge Characteristics of Cylindrical Microcavity Structure (수치해석을 통한 초미세 방전 소자의 방전 특성 연구)

  • Seo, Jeong-Hyun;Kang, Kyoung-Doo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.4
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    • pp.641-647
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    • 2008
  • In this paper, we have studied the basic discharge characteristics of ac-type cylindrical microcavity structure. The structure has a two electrodes, which are positioned in the bottom of the cavity and in the side wall of the cylinder, respectively. The discharge showed asymmetric phenomena depending on the position of a cathode electrode. When the bottom electrode was a cathode, the discharge was stronger even though the area of the cathode was smaller than that of the anode. Simulation results revealed that the focused electric field toward the bottom electrode increased ion density in the space which in turn strengthened the cathode sheath and ionization process.