• Title/Summary/Keyword: ethylene carbonate

Search Result 98, Processing Time 0.029 seconds

Effects of Lithium Bis(Oxalate) Borate as an Electrolyte Additive on High-Temperature Performance of Li(Ni1/3Co1/3Mn1/3)O2/Graphite Cells (LiBOB 전해액 첨가제 도입에 따른 Li(Ni1/3Co1/3Mn1/3)O2/graphite 전지의 고온특성)

  • Jeong, Jiseon;Lee, Hyewon;Lee, Hoogil;Ryou, Myung-Hyun;Lee, Yong Min
    • Journal of the Korean Electrochemical Society
    • /
    • v.18 no.2
    • /
    • pp.58-67
    • /
    • 2015
  • The effects of electrolyte additives, lithium bis(oxalate)borate (LiBOB), fluoroethylene carbonate (FEC), vinylene carbonate (VC), 2-(triphenylphosphoranylidene) succinic anhydride (TPSA), on high-temperature storage properties of $Li(Ni_{1/3}Co_{1/3}Mn_{1/3})O_2$/graphite are investigated with coin-type full cells. The 1 wt.% LiBOB-containing electrolyte showed the highest capacity retention after high temperature ($60^{\circ}C$) storage for 20 days, 86.7%, which is about 5% higher than the reference electrolyte, 1.15M lithium hexafluorophosphate ($LiPF_6$) in ethylene carbonate/ethyl methyl carbonate (EC/EMC, 3/7 by volume). This enhancement is closely related to the formation of semi-carbonate compounds originated from $BOB^-$ anions, thereby resulting in lower SEI thickness and interfacial resistance after storage. In addition, the 1 wt.% LiBOB-containing electrolyte also exhibited better cycle performance at 25 and $60^{\circ}C$ than the reference electrolyte, which indicates that LiBOB is an effective additive for high-temperature performance of $Li(Ni_{1/3}Co_{1/3}Mn_{1/3})O_2$/graphite chemistry.

Preparation and Electrochemical Properties of Polymeric Composite Electrolytes Containing Organic Clay Materials (Organic Clay가 첨가된 고분자 복합 전해질의 제조 및 전기화학적 성질)

  • Kim, Seok;Hwang, Eun-Ju;Lee, Jea-Rock;Kim, Hyung-Il;Park, Soo-Jin
    • Polymer(Korea)
    • /
    • v.31 no.4
    • /
    • pp.297-301
    • /
    • 2007
  • In this work, polymer/(layered silicate) nanocomposites (PLSN) based on poly (ethylene oxide) (PEO), ethylene carbonate (EC) as a plasticizer, lithium salt ($LiClO_4$), and sodium montmorillonite ($Na^+-MMT$) or organic montmorillonite (organic MMT) clay were fabricated. And the effects of organic MMT on the polymer matrix were investigated as a function of ionic conductivity. For the application to electrolytes an Li batteries, polymer electrolytes containing the organic nanoclays were used in this work. As a result, the spacing between layers and hydrophobicity of the organic nanoclays were increased, affecting on the exfoliation behaviors of the MMT layers in clay/PEO nanocomposites. From ion-conductivity results, the organic-MMT showed higher values than those of $Na^+-MMT$, and the MMT-20A sample that was treated by methyl dihydrogenated tallow ammonium, showed the highest conductivity in this system.

Effect of ethylene glycol on the nano-sized ZnO nanoparticles using polyol process (폴리올 공정을 이용한 에틸렌 글리콜이 나노 크기의 산화아연 나노입자에 미치는 영향)

  • Dae-Hwan Jang;Bo-Ram Kim;Dae-Weon Kim
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.34 no.4
    • /
    • pp.117-124
    • /
    • 2024
  • Zinc oxide nanoparticles were synthesized using the polyol method with ethylene glycol containing hydroxyl groups (-OH). It was confirmed that the zinc compounds prepared by the polyol method were a mixture of zinc carbonate hydroxide (Zn5(OH)6(CO3)2) and zinc oxide (ZnO) crystalline structures. Calcination at 400℃, 600℃ and 800℃ was performed to examine the effects of calcination temperature on the particle size, morphology and crystallinity of zinc oxide. ZnO powders of calcination at 800 ℃ was evaluated to particle size analysis from ethylene glycol containing precursor solution compared with distilled water based solution. The zinc oxide particles obtained from the former had a particle size of approximately 404 ± 51 nm, whereas those from the latter exhibited a more uniform nanoparticles morphology with a particle size of approximately 109 ± 29 nm. This demonstrates that the addition of ethylene glycol can control the influence of water molecules, enabling the direct synthesis of zinc oxide in the form of uniform nanoparticles.

Kinetics and Optimization of Dimethyl Carbonate Synthesis by Transesterification using Design of Experiment

  • Lee, Kilwoo;Yoo, Kye Sang
    • Korean Chemical Engineering Research
    • /
    • v.56 no.3
    • /
    • pp.416-420
    • /
    • 2018
  • A comprehensive kinetic study has been conducted on dimethyl carbonate synthesis by transesterification reaction of ethylene carbonate with methanol. An alkali base metal (KOH) was used as catalyst in the synthesis of DMC, and its catalytic ability was investigated in terms of kinetics. The experiment was performed in a batch reactor at atmospheric pressure. The reaction orders, the activation energy and the rate constants were determined for both forward and backward reactions. The reaction order for forward and backward reactions was 0.87 and 2.15, and the activation energy was 12.73 and 29.28 kJ/mol, respectively. Using the general factor analysis in the design of experiments, we analyzed the main effects and interactions according to the MeOH/EC, reaction temperature and KOH concentration. DMC yield with various reaction conditions was presented for all ranges using surface and contour plot. Furthermore, the optimal conditions for DMC yield were determined using response surface method.

Synthesis and Shape Control of Calcium Carbonate Fine Powders by Liquid-Gas Reaction Method (액상-기상 반응법에 의한 탄산칼슘 미분말의 합성과 형상제어)

  • 민경소;최상흘
    • Journal of the Korean Ceramic Society
    • /
    • v.28 no.3
    • /
    • pp.205-214
    • /
    • 1991
  • Calcium carbonate fine powders were synthesized by blowing CO2 gas in CaO or Ca(OH)2 suspension, and the shapes of powders obtained were examined for each synthetic condition. When water was used as a solvent, ultrafine calcite powders with the average size of∼0.03$\mu\textrm{m}$ were obtained. When synthesized using methanol as a solvent, amorphous phase and spherical vaterite phase were obtained by suction filtering and non-filtering, respectively. Reaction did not occured in ethanol medium, but spherical vaterite phase was obtained by adding ethylene glycol in ethanol.

  • PDF

Suppression of Aluminum Corrosion in Lithium Bis(trifluoromethanesulfonyl)imide-based Electrolytes by the Addition of Fumed Silica

  • Louis, Hamenu;Lee, Young-Gi;Kim, Kwang Man;Cho, Won Il;Ko, Jang Myoun
    • Bulletin of the Korean Chemical Society
    • /
    • v.34 no.6
    • /
    • pp.1795-1799
    • /
    • 2013
  • The corrosion property of aluminum by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt is investigated in liquid and gel electrolytes consisting of ethylene carbonate/propylene carbonate/ethylmethyl carbonate/diethyl carbonate (20:5:55:20, vol %) with vinylene carbonate (2 wt %) and fluoroethylene carbonate (5 wt %) using conductivity measurement, cyclic voltammetry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. All corrosion behaviors are attenuated remarkably by using three gel electrolytes containing 3 wt % of hydrophilic and hydrophobic fumed silica. The addition of silica particles contributes to the increase in the ionic conductivity of the electrolyte, indicating temporarily formed physical crosslinking among the silica particles to produce a gel state. Cyclic voltammetry also gives lower anodic current responses at higher potentials for repeating cycles, confirming further corrosion attenuation or electrochemical stability. In addition, the degree of corrosion attenuation can be affected mainly by the electrolytic constituents, not by the hydrophilicity or hydrophobicity of silica particles.

Synthesis Catalytic Application of Several$d^8Transition Metal Diphosphine Complexes, (MCl_2PP) (M = Ni^{2+}, Pd^{2+}, Pt^{2+}, Au^{3+} ; PP = diphosphines)$ (몇가지 $d^8$ 전이금속-디포스핀 착물 ($MCl_2PP$)의 합성과 촉매적 응용 (M = $Ni^{2+}$, $Pd^{2+}$, $Pt^{2+}$, $Au^{3+}$ ; PP = diphosphines))

  • Park Yu-Chul;Kim Kyung-Chae;Cho Young-Jae
    • Journal of the Korean Chemical Society
    • /
    • v.36 no.5
    • /
    • pp.685-691
    • /
    • 1992
  • The $d^8$-transition metal complexes containing diphosphine, $MCl_2PP$ were prepared by using $K_nMCl_m$ as starting materials, wherein M were Ni(II), Pd(II), Pt(II) and Au(III) and PP were bis(diphenylphosphino)methane(dppm), bis(diphenylphosphino)ethane(dppe), bis(diphenylphosphino)propane (dppp) and bis(diphenylphosphino)ethylene(dppety). The complexes were characterized by the spectral property $(^H-NMR$, $^{31}P-NMR$ and UV-Visible spectra) together with elemental analysis. The complexes were tested for the catalytic activity on the formation reactions of 3(2H)-furanone and cyclic carbonate. The only Ni(II)- and Pd(II)-diphosphine complexes displayed a good catalytic effects in the production of 3(2H)-furanone from 2-methyl-3-butyn-2-ol [reaction (1)]. But all the diphosphine complexes as catalyst were almost inactive towards cyclic carbonate production preaction [reaction (2)].

  • PDF

Characterization of a New Poly(acrylonitrile-itaconate) based Gel-electrolyte (새로운 poly(acrylonitrile-itaconate)공중합체를 기초로 한 젤-전해질의 특성)

  • Choi B. K.;Kim S. H.;Gong M. S.
    • Journal of the Korean Electrochemical Society
    • /
    • v.3 no.3
    • /
    • pp.169-172
    • /
    • 2000
  • A new gel polymer electrolyte based on the modified polyacrylonitrile (PAN), polyacrylonitrile-co-bis[2-(2-methoxyethoxy)ethyl]itaconate (abbreviated as PANI) copolymer was synthesized in expectation of enhanced trapping ability of liquid electrolytes. PAN and PANI blend was complexed with organic solvents, ethylene carbonate (EC) and dimethyl carbonate (DMC), and $LiClO_4$ salt. The highest room temperature conductivity of $2\times10^{-3}\;Scm^{-1}$ was found for a film of 25PAN+10PANl+50EC/DMC+$15LiClO_4$. The solvent-rich crystalline part decreases due to the blending of PANI and therefore number of charge carriers increases giving higher ionic conductivity. The addition of PAM as a host polymer in the PAN-based gels has beneficial effects such as higher ionic conductivity, better thermal characteristics, better miscibility with solvent, wider electrochemical stability, and better interfacial stability with lithium electrode, though it exhibits slightly less mechanical rigidity.

Preparation and Characterization of Chemical Gel Based on [Epoxy/PEG/PVdF-HFP] Blend for Lithium Polymer Battery Applications ([Epoxy/PEG/PVdF-HFP] 복합체를 이용한 리튬고분자전지용 화학겔의 제조 및 분석)

  • Kim, Joo-Sung;Seo, Jeong-In;Bae, Jin-Young
    • Polymer(Korea)
    • /
    • v.33 no.6
    • /
    • pp.544-550
    • /
    • 2009
  • In this study, we have designed [Epoxy/PEG] polymer gel electrolyte systems by thermal curing the mixtures of epoxy, PEG, imidazole catalyst, and a plasticizer of 1:1 ethylene carbonate and propylene carbonate in the presence of $LiPF_6$ salt. In order to enhance the poor mechanical property of the Corresponding [Epoxy/PEG] gel electrolyte PVdF-HFP was incorporated into the system. The ionic conductivities of the polymer gel electrolytes were related to the amount of PVdF-HFP in blends as well as the amount of liquid electrolyte. The optimized gel system showed room-temperature conductivities of $2.56\times10^{-3}S/cm$.

Preparation and Electrochemical Behaviors of Polymer Electrolyte Based on PEO/PMMA Containing Li Ion (Li 이온 포함하는 PEO/PMMA 고분자 전해질의 제조 및 전기화학적 거동)

  • Han, A-Reum;Park, Soo-Jin;Shin, Jae-Sup;Kim, Seok
    • Korean Chemical Engineering Research
    • /
    • v.47 no.4
    • /
    • pp.476-480
    • /
    • 2009
  • A polymer composite electrolyte of a blend of poly(methyl methacrylate)(PMMA) and poly(ethylene oxide) (PEO) as a host polymer, the ethylene carbonate as a solvent, and $LiClO_4$ as a salt was studied. The crystallinity of the polymer electrolytes was evaluated using differential scanning calorimeter(DSC). The ionic conductivity of the polymer electrolytes was measured by frequency response analyzer(FRA) method. The effect of PEO/PMMA blend ratios on the ionic conduction in these electrolytes was investigated. The electrolyte films showed a phase separation due to immiscibility of the PMMA with the PEO. The PMMA-rich phase and the PEO-rich phase were produced during a film casting. The ionic conductivity of blend electrolyte was dependent on the content of PMMA and showed the highest value at 20 wt.%. However, when PMMA content exceeds 20 wt.%, the ionic conductivity was decreased due to the slow ionic transport through the PMMA-rich phase.