• Title, Summary, Keyword: Ionic conductivity

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Synthesis and Ionic Conduction Behavior of Linear Phosphate-Polyether Copolymers (선형 포스페이트-폴리에테르 공중합체의 합성과 이온전도거동)

  • 김성훈;김준영;김재경;조현남;김정엽
    • Textile Science and Engineering
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    • v.35 no.11
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    • pp.685-692
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    • 1998
  • Linear phosphate-polyether copolymers (LPC) were synthesized by polycondensation reaction of methylphosphorodichloridate with poly(ethylene glycol) (PEG) and/or poly(tetramethylene glycol) (PTMG) to increase local segmental motion for improved ion transport and ionic conductivity at ambient temperatures. Ionic conductivity and thermal behavior of LPC-salt systems were investigated at various copolymer compositions, salt concentrations and temperatures. The PEG(70)/PTMG(30)/LiCF$_3$SO$_3$ electrolyte exhibited ionic conductivity of 8.04$\times$10$^{-5}$ S/cm at 25 $^{\circ}C$. Salt concentration exhibiting highest ionic conductivity was considerably dependent on EO/TMO compositions in LPC-salt systems. Effect of chain flexibility and solvating ability of host polymer on the ionic conductivity was investigated theoretically with the Adam-Gibbs configurational entropy model. For LPC6 series-salt systems, the temperature dependence on the ionic conductivity fitted well to Vogel-Tamman-Fulcher (VTF) behavior. VTF parameters and apparent activation energy were evaluated by a non-linear least square analysis. These results suggested that the solvating ability of host polymer might be a more dominating factor in improving the ionic conductivity than chain mobility.

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Ionic Conductivity of Anion Receptor Grafted Siloxane Polymers for Solid Polymer Electrolytes

  • Lee, Won-Sil;Kim, Dong-Wook;Lee, Chang-In;Woo, Seong-Ihl;Kang, Yong-Ku
    • Journal of Electrochemical Science and Technology
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    • v.2 no.1
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    • pp.26-31
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    • 2011
  • We have prepared siloxane polymers grafted with trifluoromethane-sulfonylamide and oligoether side chains for solid polymer electrolytes with enhanced ionic conductivity. The grafted trifluoromethane sulfonylamide groups seem to be effective as an anion recepting site to enhance the ionic conductivity of the solid polymer electrolyte. The anion receptor grafted siloxane polymers showed one order of magnitude higher ionic conductivity than the siloxane polymers without anion receptor grafts. The fitting parameter A of the VTF plot which was related to the carrier density of the electrolyte increased with increasing the number of grafted anion receptor. The results of experiment indicate that the anion-complexing site of the anion receptor grafted polymer host effectively traps the anions. The anion receptor grafted polymer was found to be a promising material for lithium polymer batteries.

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 $25^{\circ}C$.

Electrochemical Characterization of Lithium Polyelectrolyte Based on Ionic Liquid

  • Cha, E.-H.;Lim, S.-A.;Kim, D.-W.;Choi, N.-S.
    • Journal of the Korean Electrochemical Society
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    • v.12 no.3
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    • pp.271-275
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    • 2009
  • Five novel lithium polyelectrolyte-ionic liquid systems, using poly (lithium 2-acrylamido-2-methyl propanesulfonate; PAMPSLi) were prepared and their electrochemical properties were measured. The ionic conductivity of the PAMPSLi/1-ethyl-3-methylimidazolium tricyano methanide (emImTCM) system was exhibited high conductivity (1.28 $\times$ $10^{-3}$ $S/cm^{-1}$). The high conductivity and low viscosity of PAMPSLi/emImTCM system is due to the high flexibility of imidazolium cation and dissociation of lithium cation from the polymer chains. The PAMPSLi/N,N-dimethyl-N-propyl-Nbutylammonium tricyanomethanide ($N_{1134}TCM$) and PAMPSLi/N, N-dimethyl-N-propyl-N-butylammonium dicyanamide ($N_{1134}DCA$) systems showed fairly high conductivity (6.3 $\times$ $10^{-4}$ $S/cm^{-1}$, 6.0 $\times$ 10.4 S/cm.1). PAMPSLi/Trihexyl (tetradecyl) phosphonium bis (trifluoromethane sulfonyl) amide ($P_{66614}TFSA$) exhibited low conductivity (2.22 $\times$ $10^{-5}$ $Scm^{-1}$) and thermally stable over 400$^{\circ}C$.

Characterization of Ionic Liquid Contained Polymer Gel Electrolyte (이온성 액체를 함유한 고분자 겔 전해질의 특성연구)

  • Ryu, Sang-Woog;Song, Eui-Hwan
    • Polymer Korea
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    • v.32 no.1
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    • pp.85-89
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    • 2008
  • Acrylate polymer gel electrolytes containing N-methoxymethyl-N-methylpyrrolidium bis (trifluoro - methansulfonyl) imide (MPSI) as an ionic liquid were synthesized by solution polymerization in the presence of carbonate solvent. ionic conductivity and mechanical properties of the polymer gel electrolytes were investigated by impedance analyzer and universal testing machine as a function of the amount of polymer, and ionic liquid and type of crosslinker. The maximum ionic conductivity of polymer gel electrolytes was 0.8 mS/cm at $25^{\circ}C$ with 15 wt% of polymer, 30 wt% of ionic liquid and 5 wt% of crosslinker. The mechanical analysis showed that the tensile strength of polymer gel electrolytes increased with additional polymer contents and had the maximum value of 0.5 MPa with a reasonable ionic conductivity.

The correlation between ionic conductivity and cell performance with various compositions of polymer electrolyte in dye-sensitized solar cells (염료감응형 태양전지에서의 고분자 전해질 종류에 따른 이온전도도와의 상호관계)

  • Cha, Si-Young;Kim, Su-Jin;Lee, Yong-Gun;Kang, Yong-Soo
    • 한국신재생에너지학회:학술대회논문집
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    • pp.306-308
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    • 2007
  • Poly(ethylene glycol) dimethyl ether (PEGDME)/fumed silica/ 1-methyl -3-propylimidazolium iodide (MPII)/$I_2$ mixtures were used as polymer electrolytes in solid state dye-sensitized solar cells (DSSCs). The contents of MPII were changed and the concentration of $I_2$ was fixed at 0.1 mole% with respect to the MPII. The maximum ionic conductivity was obtained at [EG]:[MPII]:[$I_2$]=10:1.5:0.15. It was supposed that the maximum of ionic conductivities would match with that of cell efficiencies, if the ionic conductivity is a rate determining step in the sol id state DSSCs. However, the maximum composition did not show the maximum solar cell performance, indicating the mismatch between ionic conductivity and cell performance. This suggests that the ionic conductivity may not be the rate controlling step in determining the cell efficiency in these experimental conditions, whereas other parameters such as the electron recombination might play an important role. Thus, we tried to modify the surface of the $TiO_2$ particles by coating a thin metal oxide such as $Al_2O_3$ or $Nb_2O_5$ layer to prevent electron recombination. As a result, the maximum of the cell efficiency was shifted to that of the ionic conductivity. The peak shifts were also attempted to be explained by the diffusion coefficient and the lifetime of electrons in the $TiO_2$ layer.

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Effect of Li on the Ionic Conductivity and Leaching in Simulated Borosilicate Glasses

  • 이종규;김종구;김승수;지광용;전관식
    • Bulletin of the Korean Chemical Society
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    • v.18 no.7
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    • pp.740-743
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    • 1997
  • The ionic conductivity of several simulated borosilicate glasses was measured in the temperature range 150-600℃ in air. Leaching experiments were also carried out using Soxhlet apparatus at 100 ℃ for 7 days. As Li+ ion increased in simulated borosilicate glasses, both the ionic conductivity and leaching rate increased. The activation energy in the ionic conduction of the simulated borosilicate glasses was 1.38-1.45 eV in the high temperature region and 0.93-1.1 eV in the low temperature region.

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Dielectric Characterization of Unsaturated Polyester Curing (불포화 폴리에스터의 경화에 따른 유전특성 연구)

  • 오경성;김홍경;김명덕;남재도
    • Polymer Korea
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    • v.26 no.6
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    • pp.728-736
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    • 2002
  • The thermal and dielectric properties of unsaturated polyester resin system during cure were analyzed under Isothermal conditions. Both $varepsilon$′ and $varepsilon$" decreased and dipole relaxation was observed under isothermal conditions during cure. The ionic conductivity decreased linearly with the conversion according to the Kienle-Rate equation (ln($varepsilon$"$_{ionic}$we$_{0}$)=C$_{r}$$alpha$+C$_{0}$) up to $alpha$=0.15, after which it aparted from the relationship due to the entanglement of polymer chains. The effect of ionic conductivity was revealed to be larger than that of dipole motion during the whole cure through the electrical modulus analysis. Although dielectric motion was analyzed with Debye model, it was observed only at a narrow time region of middle stage of cure. In order to estimate the dielectric properties during the whole cure, the Havriliak-Negami model was considered and modified with the strong effect of ionic conductivity. The changes of $varepsilon$′ and $varepsilon$" were well estimated with this modified Havriliak-Negami model.

Dependence of the lithium ionic conductivity on the B-siteion substitution in $(Li_{0.5}La_{0.5})Ti_{1-x}M_xO_3$

  • Kim, Jin-Gyun;Kim, Ho-Gi
    • Electrical & Electronic Materials
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    • v.11 no.11
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    • pp.9-17
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    • 1998
  • The dependence of the ionic conductivity on the B-site ion substitution in (Li0.5La0.5)Ti1-xMxO3 (M=Sn, Zr, Mn, Ge) system has been studied. Same valence state and various electronic configuration and ionic radius of Sn4+, Zr4+, Mn4+ and Ge4+(4d10(0.69$\AA$), 4p6(0.72$\AA$), 3d10(0.54$\AA$) and 3d3(0.54$\AA$), respectively) induced the various crystallographic variaton with substitutions. So it was possibleto investigate the crystallographic factor which influence the ionic conduction by observing the dependence of the conductivity on the crystallographic factor which influence the ionic conduction by observing the dependence of the conductivity on the crystallographic variations. We found that the conductivity increased with decreasing the radii of B-site ions or vice versa and octahedron distortion disturb the ion conduction. The reason for this reciprocal proportion of conductivity on the radius of B-site ions has been examined on the base of the interatomic bond strength change due to the cation substitutions. The results were good in agreement with the experimental results. Therefore it could be concluded that the interatomic bond strength change due to the cation substitutions may be the one of major factors influencing the lithium ion conductivity in perovskite(Li0.5La0.5) TiO3system.

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Electrical Conduction in $SrZr_{0.95}Y_{0.05}O_{2.975}$ Ceramics

  • Baek, Hyun-Deok;Noh, Jin-Hyo
    • The Korean Journal of Ceramics
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    • v.5 no.3
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    • pp.288-295
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    • 1999
  • Partial conductivities contributed by electron holes, oxygen ions, and protons were caluclated in $SrZr_{0.95}Y_{0.05}O_{2.975}$, using the reported formulae derived from the defect chemistry of HTPCs. Required parameters were obtained from the graphical analysis of total conductivity variation against partial pressure of water vapor and oxygen. Predicted overall conductivities showed a reasonable agreement with experimental measurements. The conductivity of the material showed a linear increase with square root of the water vapor pressure. This increase was due to proton conduction in an almost pure ionic conductivity. The calculation of partial conductivities at $800^{\circ}C$ resulted in an almost pure ionic conductivity at $P_{02}=10^{-10}$ atm and a predominant hole conductivity at $P_{02}=10^{-10}$ atm. Pure proton conduction was not expected at this temperature, contrary to the earlier reports. Discussions were made in relation with reported thermodynamic data and defect structure of the material. It was shown that from the total conductivity dependence on water vapor pressure, the pure ionic conductivity at low oxygen partial pressures could be separated into protonic and oxygen ionic conductivity in $ZrO_2$-based HTPCs.

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