• Title/Summary/Keyword: ethylene carbonate

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Characterization of Porous Poly(vinylidene fluoride)/Poly(ethylene carbonate) Membranes for Polymer Electrolytes of Lithium Secondary Batteries (리튬 이차전지 고분자 전해질용 다공성 Poly(vinylidene fluoride)/Poly(ethylene carbonate) 막의 특성 연구)

  • Jeon, Jae-Deok;Kwak, Seung-Yeop
    • Proceedings of the Membrane Society of Korea Conference
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    • 2004.05b
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    • pp.69-72
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    • 2004
  • So far the most practical polymer electrolytes are gel systems, which contain a polymeric matrix, a lithium salt, and aprotic organic solvents. This has met with success but has had disadvantages that the addition of solvents promotes deterioration of the electrolyte's mechanical properties and increases its reactivity towards the lithium metal anode.[1](omitted)

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Density Functional Studies of Ring-Opening Reactions of Li+-(ethylene carbonate) and Li+-(vinylene carbonate)

  • Han, Young-Kyu;Lee, Sang-Uck
    • Bulletin of the Korean Chemical Society
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    • v.26 no.1
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    • pp.43-46
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    • 2005
  • Reaction energies were determined for reductive ring-opening reactions of Li$^+$-coordinated ethylene carbonate (EC) and vinylene carbonate (VC) by a density functional method. We have also explored the ring-opening of Li$^+$-EC and Li$^+$-VC by reaction with a nucleophile (CH$_3$O$^-$.) thermodynamically. Our thermodynamic calculations led us to conclude that the possible reaction products are CH$_3$OCH$_2$CH$_2$OCO$_2$Li (O$_2$-C$_3$ cleavage) for Li$^+$-EC +CH$_3$O$^-$., and CH$_3$OCHCHOCO$_2$Li (O$_2$-C$_3$ cleavage) and CH$_3$OCO$_2$CHCHOLi (C$_1$-O$_2$ cleavage) for Li$^+$-VC +CH$_3$O$^-$.. The opening of VC would occur at the C$_1$-O$_2$ side by a kinetic reason, although the opening at the O$_2$-C$_3$ side is more favorable thermodynamically.

Synthesis of Styrenated Phenol Alkoxylate from Styrenated Phenol with Ethylene Carbonate over KOH/La2O3 Catalyst (KOH/La2O3 촉매상에서 Styrenated Phenol과 Ethylene Carbonate의 반응으로부터 Styrenated Phenol Alkoxylate의 합성)

  • Lee, Seungmin;Son, Seokhwan;Jung, Sunghun;Kwak, Wonbong;Shin, Eun Ju;Ahn, Hogeun;Chung, Minchul
    • Applied Chemistry for Engineering
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    • v.29 no.1
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    • pp.62-66
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    • 2018
  • Styrenated phenol alkoxylates (SP-A) were prepared from styrenated phenol (SP) and ethylene oxide (EO) under a homogeneous base catalyst. However, to use EO that is difficult to handle, a high-pressure reaction device capable of controlling the reaction process should be used. Additionally, when a homogeneous base catalyst is used, a neutralization process is required to remove residual bases after the reaction, and it is also difficult to separate the catalyst and the product. Therefore, in this study, we report the results of SP-A prepared from the reaction of SP and EC using only heterogeneous base catalysts. The heterogeneous base catalyst was obtained by supporting KOH on $La_2O_3$ and calcintion. Using EC instead of EO, it was possible to produce SP-A under the atmospheric rather than high-pressure reaction condition. Average molecular weights of synthesized SP-A varied greatly depending on reaction conditions. The average molecular weight of SP-A prepared using the $KOH/La_2O_3$ catalyst could be controlled arbitrarily by controlling the reaction temperature and added catalyst and EC amounts.

Conductivity properties of ion conducting polymer electrolyte based on poly(ethylene oxide) (이온전도성 poly(ethylene oxide)고분자전해질의 전도특성)

  • 김종욱;문성인;진봉수;구할본;윤문수
    • Electrical & Electronic Materials
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    • v.8 no.4
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    • pp.487-494
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    • 1995
  • The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. We investigated the effects of lithium salts, plasticizer addition, temperature dependence of conductivity and electrochemical stability window of polyethylene oxide(PEO) electrolytes. PEO electrolyte completed with LiCIO$\_$4/ shows the better conductivity than the others. PEO-LiCIO$\_$4/ electrolyte, when EO/Li$\^$+/ ratio is 8, showed adequate conductivity around room temperature. By adding propylene carbonate and ethylene carbonate to PEO-LiCIO$\_$4/ electrolyte, its conductivity was higher than that of PEO-LiCIO$\_$4/ without those. Also PEO$\_$8/LiCIO$\_$4/ electrolyte remains stable up to 4.5V vs. Li/Li.

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The Effects of Plasticizer Addition on the Conductivity of Polymer Electrolyte Based on Poly(ethylene oxide) (이온전도성 Poly(ethylene oxide) 고분자 전해질의 전도도에 미치는 가소제 첨가 효과)

  • 문성인;진봉수;김종욱;윤문수;구할본
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1994.11a
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    • pp.82-85
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    • 1994
  • The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. This paper describes effects of plasticizer addition and temperature dependence of conductivity of these PEO electrolytes. Adding propylene carbonate and ethylene carbonate to PEO-LiClO$_4$electrolyte, its conductivity was higher than PEO-LiClO$_4$ itself. Steady state current method and AC impedance used for the determination of transference number in PEO electrolyte film. The transference number of PEO$\_$8/LiClO$_4$PC$\_$5/EC$\_$5/ polymer electrolyte film is 0.45 at 60$^{\circ}C$.

Improvement of Mechanical and Electrical Properties of Poly(ethylene glycol) and Cyanoresin Based Polymer Electrolytes

  • Oh Kyung-Wha;Choi Ji-Hyoung;Kim Seong-Hun
    • Fibers and Polymers
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    • v.7 no.2
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    • pp.89-94
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    • 2006
  • Ionic conductivity and mechanical properties of a mixed polymer matrix consisting of poly(ethylene glycol) (PEG) and cyanoresin type M (CRM) with various lithium salts and plasticizer were examined. The CRM used was a copolymer of cyanoethyl pullulan and cyanoethyl poly(vinyl alcohol) with a molar ratio of 1:1, mixed plasticizer was ethylene carbonate (EC) and propylene carbonate (PC) at a volume ratio of 1:1. The conductive behavior of polymer electrolytes in the temperature range of $298{\sim}338\;K$ was investigated. The $PEG/LiClO_4$ complexes exhibited the highest ionic conductivity of ${\sim}10^{-5}S/cm$ at $25^{\circ}C$ with the salt concentration of 1.5 M. In addition, the plasticized $PEG/LiClO_4$ complexes exhibited improvement of ionic conductivity. However, their complexes showed decreased mechanical properties. The improvement of ionic conductivity and mechanical properties could be obtained from the polymer electrolytes by using CRM. The highest ionic conductivity of PEG/CRM/$LiClO_4$/(EC-PC) was $5.33{\time}10^{-4}S/cm$ at $25^{\circ}C$.

Effect of Metal Ionic Crosslinking Agents on the Water Resistance and Mechancial Properties of EVA Emulsion (EVA 에멀젼의 내수성 및 기계적 특성에 미치는 금속 이온 가교제의 효과)

  • Lee, Eun-Kyoung;Choi, Sei-Young
    • Journal of Adhesion and Interface
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    • v.9 no.2
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    • pp.24-31
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    • 2008
  • In this work, calcium hydroxide and magnesium carbonate as metal ionic crosslinking agents were used to introduce ionic crosslinking points to the ethylene vinylacetate (EVA) emulsions for the enhancement of water resistance and mechanical properties of emulsion films. The properties of EVA emulsion film were investigated in crosslinking density, thermal features, surface energy, and mechanical properties, such as tensile strength, elongation at break and tear strength. With the increasing content of metal ionic crosslinking agent, the crosslinking density of the EVA emulsion film increases, resulting into the improvement of water resistance. The surface energy and mechanical properties of the EVA emulsion film, however, showed somewhat different behaviors. The highest surface energy, tensile strength, and tear strength were observed when 0.4% for calcium hydroxide and 0.5% for magnesium carbonate was added respectively, because the EVA emulsion containing carboxylic acid forms strong carboxylate-metal bond of ionically-crosslinked system. Therefore, it can be concluded that metal ionic crosslinking agents, such as magnesium carbonate and calcium hydroxide are considered to improve water resistance and mechanical properties of the EVA emulsion.

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A Basic Study on Non-aqueous Electrolysis of Neodymium for Room-temperature Metallurgy (상온제련을 위한 네오디뮴의 비수계 전해 기초연구)

  • Park, Jesik;Lee, Churl Kyoung
    • Resources Recycling
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    • v.27 no.4
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    • pp.29-35
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    • 2018
  • In this study, the electrochemical redox behavior of neodymium in non-aqueous electrolytes was investigated to confirm the possibility of neodymium metallurgy at room temperature. The non-aqueous electrolytes include ionic liquids such as $[C_4mim]PF_6$, $[C_4mim]Cl$, and $[P_{66614}]PF_6$, ethanol which are highly soluble in neodymium salts, and mixed electrolytes based on carbonate with highly electrochemical stability. The electrochemical redox properties of neodymium were better than those of other electrolytes in the case of the mixed electrolyte based on ethylene carbonate (EC)/di-ethylene carbonate (DEC). Ethanol was added to improve the physical properties of the mixed electrolyte. Thorough the analysis about ionic conductivity of EC/DEC ratio, ethanol content and $NdCl_3$ concentration, the best electrolyte composition was 50 vol% content of ethanol and 0.5 M of $NdCl_3$. Using cyclic voltametry and linear sweep voltametry, a current peak estimated at -3.8 V (vs. Pt-QRE) was observed as a limiting current of neodymium reduction. Potentiostatic electrolysis for 18 hours at room temperature at -6 V (vs. Pt-QRE) confirmed that metallic neodymium was electrodeposited.

Enhancement of Electrolyte Properties for High Energy Density Supercapacitors by using Additive Materials

  • Kim, Cheong;Habazaki, Hiroki;Park, Soo Gil
    • Journal of Electrochemical Science and Technology
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    • v.7 no.3
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    • pp.214-217
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    • 2016
  • In this study, we studied the enhancement of the energy densities of electrochemical capacitors by improving the working voltage range of the electrolyte. To prevent the decomposition of the electrolyte, stable SEI layers were formed by reductive degradation of additive materials such as fluoro-ethylene carbonate (FEC) and vinyl ethylene carbonate (VEC) before degradation of the base electrolyte. As a result, the solution resistance (Rs) of EC:DMC + SL 20 % + VEC 1 % electrolytes observed 1.47 Ω and the charge transfer resistance (Rct) was 2.64 Ω at the open circuit voltage. Additionally, a cycle retention of 94 % was observed for EC:DMC + SL 20 % + VEC 1 % after 500 cycles at 3.5 V.

Effect of ZnCl2 Co-catalyst in the Synthesis of Dimethyl Carbonate from Ethylene Carbonate and Methanol by Using Base Catalysts (염기 촉매를 이용한 디메틸카보네이트 합성에서 ZnCl2 조촉매의 영향)

  • Kim, Dong-Woo;Park, Moon-Seok;Kim, Moon-Il;Park, Dae-Won
    • Korean Chemical Engineering Research
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    • v.50 no.2
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    • pp.217-222
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    • 2012
  • The synthesis of dimethyl carbonate(DMC) is a promising reaction for the use of naturally abundant carbon dioxide. DMC has gained considerable interest owing to its versatile chemical reactivity and unique properties such as high oxygen content, low toxicity, and excellent biodegradability. In this study, the synthesis of DMC through the transesterification of ethylene carbonate(EC) with methanol was investigated by using ionic liquid and metal oxide catalysts. The screening test of different catalysts revealed that choline hydroxide ([Choline][OH]) and 1-n-butyl-3-methyl imidazolium hydroxide([BMIm][OH]) had better catalytic performance than metal salts catalysts such as MgO, ZnO and CaO. The effects of reaction parameters such as reaction temperature, MeOH/EC mole ratio, and carbon dioxide pressure on the reactivity of [Choline][OH] catalyst were discussed. High temperature and high MeOH/EC mole ratio were favorable for high conversion of EC. However, the yield of DMC showed a maximum when carbon dioxide pressure was 1.34 MPa, and then it decreased for higher carbon dioxide pressure. Zinc chloride($ZnCl_2$) was used as co-catalyst with the ionic liquid catalyst. The mixed catalyst showed a synergy effect on the EC conversion and DMC yield probably due to the acid-base properties of the catalysts.