Showing papers on "Ionic conductivity published in 1985"
TL;DR: In this paper, the authors calculated the space charge contribution to the conductance for two-phase systems (bicrystal and dispersion) where the second phase is a "chemically inert" phase such as alumina and silica.
325 citations
TL;DR: In this paper, the authors investigated ionic conductivity σ and mobility σ in amorphous network polymers from poly(propylene oxide) (PPO) containing lithium perchlorate (LiClO4) at the concentration of 0.042 and 0.076.
Abstract: Ionic conductivity σ and mobility μ in the amorphous network polymers from poly(propylene oxide) (PPO) containing lithium perchlorate (LiClO4) at the concentration of [LiClO4]/[PO unit]=0.042 and 0.076 were investigated by means of complex impedance and time‐of‐flight methods. The σ values of the PPO–LiClO4 complexes reached 10−5 S cm−1 at 70 °C. The temperature dependence of σ deviated from a single Arrhenius behavior above a critical temperature (−1 °C and 11 °C) which approximately corresponded to the glass transition temperature Tg. The μ values were relatively high and changed from 10−6 to 10−5 cm2 V−1 s−1 in the temperature range of 40–100 °C. The Nernst–Einstein equation correlated μ with the ionic diffusion coefficient D. The Williams–Landel–Ferry equation with C1≂5 and C2≂30–50 held with a temperature dependence of D in the order of 10−8–10−7 cm2 s−1. The change in the number of ionic carriers n with temperature obeyed the Arrhenius equation with the activation energy of 0.26 and 0.34 eV. The deg...
259 citations
TL;DR: In this article, the effects of various additives were examined to improve the room temperature ionic conductivity of poly(ethylene oxide) doped with lithium salts, and an optimized composition had a much improved conductivity, achieving 10−4 (Ω cm)−1 at 40 °C.
196 citations
TL;DR: In this paper, a poly[lithium methacrylate-co-oligo(oxyethylene)methacryl] film was prepared as a polymeric solid electrolyte which showed lithium ionic conductivity of 2×10−7(S/cm).
114 citations
TL;DR: In this paper, the electrical conductivities of YSZ single crystals with various compositions covering FSZ and PSZ regions were measured by a complex impedance method and a four-probe a.c. method.
Abstract: The electrical conductivities of YSZ single crystals with various compositions covering FSZ and PSZ regions were measured by a complex impedance method and a four-probe a.c. method. The conductivities changed significantly as a function of composition. A simple conduction model for PSZ showed that the tetragonal phase is a good oxygen ionic conductor having an activation energy for motion of about 0.8 to 0.9 eV. It is promising for low temperature application of a solid state electrolyte.
111 citations
AT&T1
TL;DR: In this paper, the ionic conductivities of a series of lithium salt poly (ethylene oxide) complexes have been studied from ambient temperature to approximately 400 K. Plots of the variation of conductivity with temperature indicate a transition in behavior between 330-360 K.
105 citations
Patent•
11 Sep 1985TL;DR: A solid polymeric electrolyte is a macromolecular material in which there is dissolved an ionic compound, particularly in solution in a copolymer of ethylene oxide and a second unit selected so that the copolymers chain maintains a polyether characteristic as mentioned in this paper.
Abstract: A solid polymeric electrolyte comprises a macromolecular material in which there is dissolved an ionic compound, particularly an ionic compound in solution in a copolymer of ethylene oxide and a second unit selected so that the copolymer chain maintains a polyether characteristic. Also a high performance composite electrode embodying this electrolyte, and a process for obtaining this electrolyte.
91 citations
TL;DR: Polymere prepare a partir de bisphenylisocyanate de methylene, ethylenediamine et polyoxyde de propene de masse moleculaire 2000 ou 3000.
Abstract: Polymere prepare a partir de bisphenylisocyanate de methylene, ethylenediamine et polyoxyde de propene de masse moleculaire 2000 ou 3000
85 citations
TL;DR: In this article, a new type of polymer electrolyte called grafted polysiloxane-grafted ethylene oxide (grafted PDMS-LiClO 4 10 wt% electrolyte was proposed.
85 citations
TL;DR: In this paper, the ionic conductivity of two-phase mixtures of AgBr and Al2O3 has been measured and found to exceed the conductivities of pure AgBr considerably as long as the alumina content is lower than about 15 v/o.
77 citations
TL;DR: Preparation a partir de poly [methacryloyl oligo (oxyde d'ethylene)] et de LiOCl 4 ou LiPF 6 as mentioned in this paper.
Abstract: Preparation a partir de poly [methacryloyl oligo (oxyde d'ethylene)] et de LiOCl 4 ou LiPF 6
01 Apr 1985
TL;DR: In this article, the conduction contributions of the space charge regions in bicrystals and dispersions which may give rise to internal and external vacancy-interstitial (v-i-) junctions are discussed.
Abstract: In the space charge regions near the contact of two ionic conductors, distribution equilibria of the mobile ions — in addition to the bulk phase equilibria — have to be taken into account resulting in charged non-stoichiometric regions with modified electric properties. The thermodynamics of the interfacial behavior are considered and the concentration profiles for the defects in two Frenkel disordered conductors, which are taken as an example, are calculated using the standard defect chemical potentials of the materials as parameters. The conduction contributions of the space charge regions in bicrystals and dispersions which may give rise to internal and external vacancy-interstitial (v-i-) junctions are discussed. — The model is checked by the help of literature data on the conductivity of β-AgI/AgBr dispersions.
TL;DR: In the high-temperature polymorph Na2SO4(I) up to 30% cation vacancies can be generated by substitution of Na + by bi-and trivalent ions as discussed by the authors.
Abstract: In the high-temperature polymorph Na2SO4(I) up to 30% cation vacancies can be generated by substitution of Na + by bi- and trivalent ions. Phase diagrams and lattice parameters of these solid solutions are presented. The hexagonal high-temperature form and its monoclinic distortions can be quenched to room temperature. A structure determination was carried out. Structural and experimental data are: P63/mmc, a=5.326(2), c=7.126(3) A, V=175.06/~ 3, Z=2, Dx = 2.695 Mg m -3, h(Ag Ka) = 0"55936 fk, R = 0.09 for 165 reflections. The crystal structure is characterized by strong orientational disorder of the SOn tetrahedra. The disorder, aliovalent solid solutions, thermal expansion and ionic conductivity are discussed.
TL;DR: In this paper, an enhanced carrier concentration within the interfacial space charge layers has been proposed as one possible mechanism leading to the enhanced ionic conductivity observed for a variety of composite electrolytes containing a dispersed second phase of fine insulating particles such as Al2O3.
Abstract: An enhanced carrier concentration within the interfacial space-charge layers has been proposed as one possible mechanism leading to the enhanced ionic conductivity observed for a variety of composite electrolytes containing a dispersed second phase of fine insulating particles such as Al2O3. This study tests this proposal by estimating the maximum space-charge polarization that might reasonably occur at interfaces of nominally pure AgCl, US -AgI, and LiI. The resulting interface conductances are used in effective medium calculations of the total conductivity of a randomly distributed composite of these salts with Al2O3 particles. Comparison of the results with published conductivities for the composites shows that the modest enhancement found for AgCl/Al2O3 can be accounted for by the interfacial space-charge polarization. However, the large (50- to 500-fold) enhancements found for US -AgI/Al2O3 and LiI/Al2O3 must be attributed to another mechanism.
TL;DR: Ionic conductivity measurements were performed on polycrystalline CaF2, BaF2 and those dispersed with Al2O3 particles, and the effective thickness and electrical conductivity of the interface layer at 500° C were calculated, using a simple mixing model, to be 0.3 to ~ 0.6μm and 10−3 S cm−1, respectively as discussed by the authors.
Abstract: Ionic conductivity measurements were performed on polycrystalline CaF2, BaF2 and those dispersed with Al2O3 particles. The ionic conductivity of both CaF2 and BaF2 increased by about 1 to 2 orders of magnitude by dispersion of Al2O3 particles, while X-ray diffraction measurements showed there were no other phases present other than fluoride and Al2O3. The conductivity of the dispersed system strongly depended on the particle size and the concentration of Al2O3, which suggested the high ionic-conductivity layers were formed at the interface between the ionic conductor matrix and the Al2O3 particles. The effective thickness and electrical conductivity of the interface layer at 500° C were calculated, using a simple mixing model, to be 0.3 to ~ 0.6μm and ~ 10−3 S cm−1, respectively.
TL;DR: In this paper, it was shown that the change of static permittivity of the solution (due to the presence of solute ion-pairs and other polar species, which increase the polarization of solution) can account qualitatively for the behavior of the conductance data and their deviation from the Fuoss-Kraus theory.
Abstract: : Audiofrequency electrical conductivity data are reported in the solvent dimethylcarbonate (DMC) at 25 deg C in the concentration range 00001 to 1M for LiAsF6 and 00001 to 03M for LiClO4 From 00001 to approx = 001M the data are interpreted by the Fuoss-Kraus triple-ions theory leading to the values of the ion pair formation constant Kp and triple ion formation constant KT For the data at higher concentration, it is shown that the change of static permittivity of the solution (due to the presence of solute ion-pairs and other polar species, which increase the polarization of the solution) can account qualitatively for the behavior of the conductance data and their deviation from the Fuoss-Kraus theory These deviations are mostly due to changes in permittivity, not accounted for in the conventional treatment of the data, rather than by the failure of the theory Introduction of the quadrupole formation constant is necessary, however, for LiAsF6 for a more quantiative treatment of the conductance data Microwave complex permitivities in the concentration range 005M to 03M, frequency range approx = 1 to 90- GHz are intepreted by two Debye relaxation processes, one due to the solute and one to the solvent For LiAsF6 the Boettcher plot, (expressing a quantity related to the change of the relaxation strength with the concentration of electrolyte), is nonlinear with the concentration Keywords include: Electrical conductance, and Microwave dielectric relaxation
TL;DR: In this paper, the ion hopping rate values have been confirmed by mechanical relaxation measurements at two frequencies, 1.25 and 10 MHz, and the anomalously high conductivity prefactor, 6.3 × 10 5 ohm −1 cm −1 K, is associated with a large entropy, S, of activation.
Abstract: Measurements of the a.c. conductivity of AgIAg 2 MoO 4 glass over the temperature range − 84 to − 154°C have enabled d.c. conductivities and ion hopping rates to be obtained. The ion hopping rate values have been confirmed by mechanical relaxation measurements at two frequencies, 1.25 and 10 MHz. The anomalously high conductivity prefactor, 6.3 × 10 5 ohm −1 cm −1 K, is associated with a large entropy, S , of activation. A simple relationship between S and activator energy, E , proposed by Dienes, is shown to hold for a range of glassy Ag + conductors whereas the Wert and Zener expression seriously underestimates S , as shown by shear wave velocity and thermal expansion measurements.
TL;DR: The conduction mechanisms in nickel-doped yttrium aluminum garnet (Ni:YAG) have been studied as a function of temperature and partial pressue of oxygen.
Abstract: The conduction mechanisms in nickel‐doped yttrium aluminum garnet (Ni:YAG) have been studied as a function of temperature and partial pressue of oxygen. ac conductivity and ionic transference measurements show that Ni:YAG is a mixed ionic‐electronic conductor with an ionic mobility characterized by an activation energy of 2.0–2.2 eV. The reduction of Ni+3 to Ni+2 causes an increase in the oxygen vacancy concentration and a concurrent rise in the magnitude of the ionic conductivity. Codoping with zirconium, on the other hand, fixes the nickel in the divalent state, increases the n‐type conductivity, and lowers the degree of ionic conductivity. A defect model is presented which is consistent with all of these observations.
TL;DR: In this paper, the free energies of defect processes were calculated from a microscopic model using a large-crystallite method, and the ionic conductivity was calculated directly with experiment.
Abstract: We show how the free energies of defect processes may be calculated directly from a microscopic model. In addition to the calculation of internal energies, we also calculate the vibrational entropy, using a large-crystallite method. Using the results obtained, we comment on the nature and range of validity of the Arrhenius relation. We calculate the ionic conductivity and compare it directly with experiment. Defect volumes are also calculated and compared with the available data.
TL;DR: In this paper, alternating current and direct current methods using reversible and polarization cells, as well as concentration cells were applied to evaluate the electronic and ionic conductivities, the dielectric constant, and the phase boundary parameters as functions of temperature (700°C) and of oxygen partial pressure (10 1 −10 5 Pa).
TL;DR: In this article, a spin-lattice relaxation with nuclear magnetic resonance and ionic conductivity was used to measure the ionic properties of a solid breeder material under irradiation.
TL;DR: The phase equilibria in the zirconia-rich part of the system were determined at 1200°, 1400°, and 1650°C as mentioned in this paper, and the ionic conductivities of ternary specimens in this system were measured using the complex impedance analysis technique.
Abstract: The phase equilibria in the zirconia-rich part of the system ZrO2−Yb2O3−Y2O3 were determined at 1200°, 1400°, and 1650°C. The stabilizing effects of Yb2O3 and Y2O3 were found to be quite similar with <10 mol% of either being necessary to fully stabilize the cubic fluorite-structure phase at 1200°C. The two binary ordered phases, Zr3Yb4O12 and Zr3Y4O12, are completely miscible at 1200°C. These were the only binary or ternary phases detected. The ionic conductivities of ternary specimens in this system were measured using the complex impedance analysis technique. For a given level of total dopant, the substitution of Yb2O3 for Y2O3 gives only minor increases in specimen conductivity.
TL;DR: In this article, a threshold volume fraction of the conductive phase within perfluorosulfonic acid ionomer Nafion has been determined for a geometrical cluster-network model.
Abstract: This article deals with the method of determination of a threshold volume fraction of the conductive phase within perfluorosulfonic acid ionomer Nafion. Experiments have been performed with the commercial Nafion-120 and Nafion-427 membranes equilibrated with concentrated sodium chloride and sodium hydroxide solutions at 353 K. It has been stated that the insulator-to-conductor transition in membranes occurs at the critical volume fraction of the conductive phase (Vc) equal to 0.1. The same Vc has been estimated for a geometrical cluster-network model. Lower than the theoretical Vc for a classical dense-packed-hard-sphere model (Vc = 0.15), the volume fraction for the membranes is caused mainly by channels connecting the ionic clusters. The critical exponent t has been calculated for both membranes and found to be equal to 1.6 for Nafion-120 and 1.5 for Nafion-427. Both these constants correspond to those theoretically predicted for 3D systems. The ratios of sodium ion mobility in the internal membrane solution to its mobility in the equilibrating NaCl or NaOH solutions (u+/u+) are below unity, and they are dependent on the nature and concentration of the electrolyte.
Journal Article•
TL;DR: Ionic conductivities of layered titanates, Na2Ti3O7 and K2Ti4O9, and their derivatives were measured on the polycrystalline samples.
TL;DR: The structure of spinel-type solid solutions Li2−2xMin1+xCl4 M = Mg, V has been studied by neutron diffraction as discussed by the authors.
TL;DR: In this paper, the properties of polycrystalline KUO 2 PO 4 · 3 H 2 O (KUP) and its isotopic derivatives have been investigated in the 4000-10cm −1 range at different temperatures.
TL;DR: Ionic conductivity and mobility of poly(propylene oxide) networks Dissolving Alkali Metal Thiocyanates as mentioned in this paper, and Polypropylene Oxide Networks.
Abstract: Ionic Conductivity and Mobility of Poly(propylene oxide) Networks Dissolving Alkali Metal Thiocyanates
TL;DR: In this article, the ac conductivity of an ionically conducting glass, 0.4Ca(NO 3 ) 2 : 0.6KNO 3, is reexamined.
TL;DR: In this paper, the conductivity of a sintered pellet of Li 8 ZrO 6 was measured in dry or wet argon atmosphere by the two-terminal technique with an AC Wheatstone bridge in the temperature range 350-1050 K.