• Title/Summary/Keyword: 전해질 분석

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Electrochemical Properties of Activated Carbon Supecapacitor Containing Sulfonated Polypropylene Separator Coated with a Hydrogel Polymer Electrolyte (하이드로겔 고분자 전해질이 코팅된 술폰화 폴리프로필렌 격리막을 포함하는 활성탄 수퍼커패시터 특성)

  • Yoon, Choong Sub;Ko, Jang Myoun;Latifatu, Mohammed;Lee, Hae Soo;Lee, Young-Gi;Kim, Kwang Man;Won, Jung Ha;Jo, Jeongdai;Jang, Yunseok;Kim, Jong Huy
    • Korean Chemical Engineering Research
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    • v.52 no.5
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    • pp.553-557
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    • 2014
  • Sulfonated polypropylene (S-PP) is prepared by sulfuric acid-acetone aldol condensation reaction of polypropylene (PP) separator to yield hydrophilic separator surface with a moderate amount of $-SO_3H$ groups. Activated carbon supercapacitor is also fabricated adopting the S-PP separator coated with potassium polyacrylate (PAAK) hydrogel polymer electrolyte. As a result, the hydrophilic surface of S-PP separator involves better physical and electrochemical properties such as decrease in contact angle, improvements of wettability, electrolyte uptake, and ionic conductivity to give higher specific capacitance and long cycle-life.

Surface modification of Poly-(dimethylsiioxane) using polyelectrolYte multilayers and its characterization (다층의 고분자 전해질을 이용한 Poly-(dimetnylsiloxane)의 표면 개질 및 특성)

  • Shim, Hyun-Woo;Lee, Chang-Hee;Lee, Ji-Hye;Hwang, Taek-Sung;Lee, Chang-Soo
    • KSBB Journal
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    • v.23 no.3
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    • pp.263-270
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    • 2008
  • A poly-(dimethylsiloxane) (PDMS) surface modified by the successive deposition of the polyelectrolytes, poly-(allylamine hydrochloride) (PAH), poly-(diallyldimethylammoniumchloride) (PDAC), poly-(4-ammonium styrenesulfonic acid) (PSS), and poly-(acrylic acid) (PAA), was presented for the application of selective cell immobilization. It is formed via electrostatic attraction between adjacent layers of opposite charge. The modified PDMS surface was examined using static contact angle measurements and fourier transform infrared (FT-IR) spectrophotometer. The wettability of the PDMS surface could be easily controlled and functionalized to be biocompatible through regulation of layer numbers. The modified PDMS surface provides appropriate environment for adhesion to cells, which is essential technology for cell patterning with high yield and viability in the patterning process. This method is reproducible, convenient, and rapid. It could be applied to the fabrication of biological sensing, patterning, microelectronics devices, screening system, and study of cell-surface interaction.

Effect of Cathode Porosity on the Cathodic Polarization Behavior of Mixed Conducting LSCF(La0.6Sr0.4Co0.2Fe0.8O3) (혼합전도체 LSCF(La0.6Sr0.4Co0.2Fe0.8O3) 양극의 기공률에 따른 양극분극 특성)

  • Yun, Joong-Cheul;Lee, Jong-Ho;Kim, Joosun;Lee, Hae-Weon;Kim, Byong-Ho
    • Journal of the Korean Ceramic Society
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    • v.42 no.4
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    • pp.251-259
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    • 2005
  • In order to characterize the influence of the reaction-site density on the cathodic polarization property of LSCF, we chose the porosity of LSCF as a main controlling variable, which is supposed to be closely related with active sites for the cathode reaction. To control the porosity of cathodes, we changed the mixing ratio of fine and coarse LSCF powders. The porosity and pore perimeter of cathodes were quantitatively analyzed by image analysis. The electrochemical half cell test for the cathodic polarization was performed via 3-probe AC-impedance spectroscopy. According to the investigation, the reduction of oxygen at LSCF cathode was mainly controlled by following two rate determining steps; i) surface diffusion and/or ionic conduction of ionized oxygen through bulk LSCF phase, ii) charge transfer of oxygen ion at cathode/electrolyte interface. Moreover, the overall cathode polarization was diminished as the cathode porosity increased due to the increase of the active reaction sites in cathode layer.

Decontamination of simulated radioactive metal waste by modified electrolytic Process with neutral salt electrolytes (개선된 중성염 진해공정을 이용한 모의 방사성 금속폐기물의 제염)

  • Lee, Ji-Hoon;Yuk, Wan-Yi;Yang, Ho-Yeon;Ha, Jong-Hyun
    • Journal of Radiation Protection and Research
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    • v.27 no.2
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    • pp.95-100
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    • 2002
  • Conventional and modified electrolytic decontamination experiment were performed in the 1.7 M solution of sodium sulfate and sodium nitrate tot decontamination of carbon steel as the simulated metal wastes which have been produced in large amounts from nuclear power plants. Anode ant cathode were used as inconel and titanium respective. The reaction time and temperature were 1 hr and $25^{\circ}C$ The analyses were performed of the characteristics such as weight loss arid thickness change of metal waste. suspended solid in electrolyte and SEM observation. In modified electrolyte decontamination system with increased current density ranged from 0.1 to $0.6A/cm^2$, the metal waste showed thickness changes of $0.48{\pm}0.005$ to $67.7{\pm}0.02{\mu}m$ in 1.7 M sodium sulfate and those of $0.06{\pm}0.005$ to $17.7{\pm}0.05{\mu}m$ in sodium nitrate. Metal waste in modified electrolyte decontamination system showed the thickness change of $9.8{\pm}0.01{\mu}m$ while it reacted up to $3.7{\pm}0.03{\mu}m$ in conventional system with $0.3 A/cm^2$ of current density and 1.7 M sodium sulfate. Decontamination efficiencies of modified electrolytic process ate much hither than that of conventional electrolytic process when both are applied to metal waste.

Numerical Modeling of Current Density and Water Behavior at a Designated Cross Section of the Gas Diffusion Layer in a Proton Exchange Membrane Fuel Cell (고분자전해질 연료전지의 동작압력에 대한 가스 확산층의 위치 별 전류밀도 및 수분거동에 대한 수치해석)

  • Kang, Sin-Jo;Kim, Young-Bae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.2
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    • pp.161-170
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    • 2012
  • There are many factors to consider when attempting to improve the efficiency of fuel cell operation, such as the operation temperature, humidity, stoichiometry, operation pressure, geometric features, etc. In this paper, the effects of the operation pressure were investigated to find the current density and water saturation behavior on a cross section designated by the design geometry. A two-dimensional geometric model was established with a gas channel that can provide $H_2$ to the anode and $O_2$ and water vapor to the cathode gas diffusion layer (GDL). The results from this numerical modeling revealed that higher operation pressures would produce a higher current density than lower ones, and the water saturation behavior was different at operation pressures of 2 atm and 3 atm in the cathode GDL. In particular, the water saturation ratios are higher directly below the collector than in other areas. In addition, this paper presents the dependence of the velocity behavior in the cathode on pressure changes, and the velocity fluctuations through the GDL are higher in the output area than in inlet area. This conclusion will be utilized to design more efficient fuel cell modeling of real fuel cell operation.

Preparation and Characterization of Plasticized Poly(vinyl chloride)-g-Poly(oxyethylene methacrylate) Graft Copolymer Electrolyte Membranes (가소화된 Poly(vinyl chloride)-g-Poly(oxyethylene methacrylate) 가지형 고분자 전해질막 제조 및 분석)

  • Seo, Jin-Ah;Koh, Jong-Kwan;Koh, Joo-Hwan;Kim, Jong-Hak
    • Membrane Journal
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    • v.21 no.3
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    • pp.222-228
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    • 2011
  • Poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) graft copolymer was synthesized via atom transfer radical polymerization (ATRP) and used as an electrolyte for electrochromic device. Plasticized polymer electrolytes were prepared by the introduction of propylene carbonate (PC)/ethylene carbonate (EC) mixture as a plasticizer. The effect of salt was systematically investigated using lithium tetrafluoroborate ($LiBF_4$), lithium perchlorate ($LiClO_4$), lithium iodide (LiI) and lithium bistrifluoromethanesulfonimide (LiTFSI). Wide angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) measurements showed that the structure and glass transition temperature ($T_g$) of polymer electrolytes were changed due to the coordinative interactions between the ether oxygens of POEM and the lithium salts, as supported by FT-IR spectroscopy. Transmission electron microscopy (TEM) showed that the microphase-separated structure of PVC-g-POEM was not greatly disrupted by the introduction of PC/EC and lithium salt. The plasticized polymer electrolyte was applied to the electrochromic device employing poly(3-hexylthiophene) (P3HT) conducting polymer.

A Study on the Mechanical Properties of Single and Multiple layer Thin Film of YSZ Electrolyte Produced by E-beam Coating for Solid Oxide Fuel Cells (전자빔 코팅에 의해 제조된 고체산화물 연료전지용 YSZ 전해질 단층 및 다층박막의 기계적 특성 연구)

  • Im, Hae-Sang;Kim, Hui-Jae;Park, Jong-Wan
    • Korean Journal of Materials Research
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    • v.9 no.8
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    • pp.792-797
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    • 1999
  • The 8mol.%Y$_2$$O_3$-$ZrO_2$mainly employed as an electrolyte of solid oxide fuel cells(SOFCs) shows excellent electrical properties but has a weakness in the mechanical properties. Since the electrolyte of SOFCs requires both good electrical and mechanical properties, this study was conducted to meet both requirements. The electrolyte thin films were produced on the LSM(cathode material) substrate of a cell and Si wafer. Four electrolyte film types of single layer and the multiple layer, consisting of 3-YSZ(3mol.%$Y_2$$O_3$) with excellent mechanical properties and 8-YSZ with the excellent electric conduction, were produced by electron beam coating technology. Ther crystal structure and the mechanical properties were also analysed. As the results of the study, the 3-YSZ thin film turned out to be in the tetragonal, partially monoclinic phase, while the 8-YSZ thin film showed the cubic phase. The residual stress in the multiple layer was lower than that of the single layer. The microhardness of the multiple layer was similar to that of the existing 8-YSZ single layer both before and after annealing treatment.

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Preparation and Characterization of Random Copolymer Electrolyte Membranes Containing PFCB (Perfluorocyclobutane) Group (PFCB (Perfluorocyclobutane) Group을 포함한 랜덤 공중합체 고분자 전해질 막 제조 및 특성연구)

  • Kim Jeong-Hoon;Kim Dong-Jin;Chang Bong-Jun;Lee Soo-Bok;Joo Hyeok-Jong
    • Membrane Journal
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    • v.16 no.3
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    • pp.221-229
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    • 2006
  • This study is about the preparation and characterization of sulfonated random copolymer membranes containing perfluorocyclobutane (PFCB), fluorenyl, and sulfonyl units. The polymers were prepared through three synthetic steps, that is, the synthesis of a trofluorovinylether-terminated monomer, its thermal polymerization, and post-sulfonation using chlorosulfonic acid. A series of sulfonated random copolymers with different ion exchange capacity (IEC) were prepared by changing contents of fluorenyl uints in polymers with fixed molar ratio of chlorosulfonic acid during the post-sulfonation reaction. All the synthesized compounds were characterized by FT-lR, $^1H-NMR$, $^{19}F-NMR$, and Mass spectroscopy. As the content of sulfonated fluorenyl units increased, the IEC, water uptake, and ion conductivity of the sulfonated random copolymer membranes increased. The sulfonated random copolymer S-1 and S-2 showed higher values of ion conductivity than the Nafion-115 in a wide range of temperatures ($25{\sim}80^{\circ}C$).

Performance Analysis of Pyrotechnic Devices on the Reliability of Thermal Batteries (열전지의 신뢰성에 미치는 파이로테크닉 부품의 특성분석)

  • Cheong, Hae-Won;Kang, Sung-Ho;Kim, Kiyoul;Cho, Jang-Hyeon;Ryu, Byungtae;Baek, Seung-Su
    • Journal of the Korean Society of Propulsion Engineers
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    • v.23 no.1
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    • pp.116-123
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    • 2019
  • Thermal batteries are also called molten-salt batteries as the electrolyte is mainly composed of molten salt. The molten-salt electrolyte is a solid that does not conduct electricity at room temperature, but when it is melted by a pyrotechnic heat source, it becomes an excellent ionic conductor. Thermal batteries are a kind of pyrotechnic battery because they operate only when the solid electrolyte is melted by the heat energy provided by pyrotechnic materials. Pyrotechnic components used in a thermal battery include heat sources, fuse strips, and an igniter. The reliability of these pyrotechnic components critically affects the reliability and performance of the battery that must supply electricity stably to guided munitions even under extreme environmental conditions. Different igniter types offer different advantages: notch-type igniters offer improved ignition probability, whereas film-type igniters offer improved safety. The addition of metal oxides to the heat paper could improve the burn rate, and the ignition reliability could be greatly improved by using it with a flame igniter at the same time. Using a two-step reduction process, high-purity Fe particles in coral form can be safely obtained.

Degradation Evaluation of PEM Water Electrolysis by Method of Degradation Analysis Used in PEMFC (고분자전해질 연료전지 열화 분석방법에 의한 PEM 수전해 열화 평가)

  • Oh, Sohyeong;Yang, Jinwon;Chu, Cheun-Ho;Na, Il-Chai;Park, Kwonpil
    • Korean Chemical Engineering Research
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    • v.59 no.1
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    • pp.1-5
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    • 2021
  • The PEM(Proton Exchange Membrane)water electrolysis uses the same PEM electrolyte membrane as the PEM fuel cell and proceeds by the same reaction but the opposite direction. The PEM fuel cell has many methods of degradation analysis since many studies have been conducted on the degradation and durability of the membrane and catalyst. We examined whether PEM fuel cell durability evaluation method can be applied to PEM electrolytic durability evaluation. During the PEM electrolytic degradation process, LSV(Linear sweep voltammetry), CV(Cyclic voltammetry), Impedance, SEM(Scanning Electron Microscope) and FT-IR(Fourier Transform Infrared spectroscopy) were analyzed and compared under the same conditions as the PEM fuel cell. As the PEM fuel cell, hydrogen passing through the membrane was oxidized at the Pt/C electrode, and the hydrogen permeation current density was measured to analyze the degree of degradation of the PEM membrane. Electrode degradation could be analyzed by measuring the electrode active area (ECSA) by CV under hydrogen/nitrogen flowing conditions. While supplying hydrogen and air to the Pt/C electrode and the IrO2 electrode, the impedance of each electrode was measured to evaluate the durability of the electrode and membrane.