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Showing papers on "Ionic conductivity published in 1976"


Journal ArticleDOI
TL;DR: In this paper, it was shown that the defect energy required for the formation of a defect pair greatly exceeds the thermal energy, kBT, in a typical ionic crystal, and the same is true of the ionic conductivity.

230 citations


Journal ArticleDOI
TL;DR: In this article, the authors measured the emf of a galvanic cell within the temperature range between 700° and 800°C as a function of the oxygen partial pressure at which the ionic transference number of the solid solution becomes 0.5.
Abstract: The solid solutions exhibit high ionic conduction due to the migration of O2− ions via oxygen ion vacancies. The emf of a galvanic cell,, is measured within the temperature range between 700° and 800°C as a function of . At such high oxygen pressures as in air, the emf changes according to indicating the ionic transference number in the solid solution is unity. With decreasing oxygen pressure, however, the observed emf becomes smaller than the theoretical value. This indicates the onset of electronic conduction generated by the reduction of the solid solution. The dependence of the emf on is described bywhere is a constant corresponding to the oxygen partial pressure at which the ionic transference number of the solid solution becomes 0.5. From the temperature dependence of , partial molar enthalpy changes for the reduction of are calculated.

227 citations



Journal ArticleDOI
TL;DR: In this article, the ionic conductivity of polycrystalline lithium nitride has been determined using ac techniques and complex plane analysis, showing that this material may be an interesting lithium-conducting solid electrolyte.

99 citations


Journal ArticleDOI
TL;DR: The ionic conductivities of samples of lithium orthosilicate containing up to 50 mole % of lithium phosphate have been measured by both a c and d c techniques as discussed by the authors, indicating a large enhancement in lithium ion conduction due to the presence of the phosphate, making these materials attractive candidates for use as solid electrolytes in applications such as battery systems.

88 citations


Journal ArticleDOI
TL;DR: The high temperature heat content of crystalline PbF 2 increases rapidly between 625 and 750 K, with an antropy incre ase of 16.5 JK -1 mol -1.

72 citations


Journal ArticleDOI
TL;DR: In this article, the concept of local structure of a polymer in the neighborhood of an ion is considered along with the relation of ionic conduction to the entropy correlation theory recently developed by Barker and applied to the case of diffusion in oriented polymers by Barker, Tsai, and Willency.
Abstract: There often has been great uncertainty as to whether typical measurements allow one to conclude that conduction in a given polymer is due predominately to ions or to electrons. Many researchers have assumed that relatively pure polymers can be treated as wide band gap semi-conductors but other scientists have believed that most non-conjugated polymers conduct by the movement of ions. Part of the trouble is that many of the theories predict dependences of current on voltage and sample thickness too similar to easily distinguish between the assumed mechanisms unless extensive and very good data are available. Some comparisons are discussed. More recent approaches that use pressure as an added variable, or those that give careful consideration to such things as gas evolution often allow one to deduce the predominant type of conduction. The concept of local structure of a polymer in the neighborhood of an ion is considered along with the relation of ionic conduction to the entropy correlation theory recently developed by Barker and applied to the case of diffusion in oriented polymers by Barker, Tsai, and Willency. According to the evidence, the activation entropy increases under the action of an organizing effect such as uniaxial elongation. Moisture has two important effects on conduction in polymers. At low concentrations it contributes charge carriers by its own dissociation and at higher concentrations it enhances the dissociation of other ionic species present. Some data for the correlation of conductivity and dielectric constant of solid polymers are discussed in terms of the weak electrolyte model developed by Sharbaugh and Barker for organic liquids. The existence of the correlation seems to imply that many polymers, under most circumstances, are predominantly ionic conductors.

71 citations


Journal ArticleDOI
TL;DR: The ionic conductivity of copper selenide was measured in the temperature range of 30 − 180°C by blocking the electronic current by the copper ion high conductivity solid electrolyte, 37CuBr·3[C 6 H 12 N 2 ·2CH 3 Br] as mentioned in this paper.

70 citations


Journal ArticleDOI
TL;DR: In this article, the ionic conductivity for a solid in which the ions are undergoing an order-disorder phase transition is calculated for a lattice gas with a weak hopping term.
Abstract: The ionic conductivity is calculated for a solid in which the ions are undergoing an order-disorder phase transition. The interacting ion system is described by a lattice gas with a weak hopping term. Exact results are obtained in one and two dimensions by using the exact results known for the Ising model. The calculated theoretical conductivity agrees very well with the temperature dependence found experimentally.

66 citations


Journal ArticleDOI
TL;DR: In this article, the authors measured the transport number of Ag ions in the glass-forming region in the system P 2 S 5 Ag 2 S glasses and found that the transport numbers of Ag ion sites in the nonconducting framework composed of both S anions and As, Ge or P cations.
Abstract: The glass-forming region in the system PSAg was determined and density, thermal expansion, dc conductivity and the transport number of Ag ions were measured for P 2 S 5 Ag 2 S glasses found in the PSAg system. The results for the transport number measurement show that P 2 S 5 Ag 2 S glasses are purely ionic conductors owing to the Ag ion migration, like most of the As 2 S 3 Ag 2 S and GeS 2 GeSAg 2 S glasses reported previously. Glass structure and ionic conduction processes in As 2 S 3 Ag 2 S, GeS 2 GeSAg 2 S and P 2 S 5 Ag 2 S glasses are discussed, based on their ionic conductivity and density data. The structural concept of α-Ag 2 S was applied to these glasses, which suggests that the Ag ions in the glasses are distributed in the available Ag ion sites in the non-conducting framework composed of both S anions and As, Ge or P cations. In each system the ionic conductivity increases linearly with increasing Ag + /total cation (%) in glass composition, the determining factor being the activation energy for ionic conduction alone. Thus, the activation energy in these glasses depends predominantly upon the molar ratio of Ag ions to total cation in the glass, irrespective of the kind of system. Small differences in the activation energy among the three systems can be interpreted as arising from differences in the field strength of As, Ge and P cations.

63 citations



Journal ArticleDOI
TL;DR: In this article, the authors measured the conductivities of Li4SiO4 and its solid solutions with Li4GeO4 over a wide frequency range to separate clearly the effects of electrode polarization, conductance relaxations, etc., and to obtain true “dc” conductivities.
Abstract: Conductivity was measured for Li4SiO4 and its solid solutions with Li4GeO4 over a wide frequency range to separate clearly the effects of electrode polarization, conductance relaxations, etc., and to obtain true “dc” conductivities. The conductivities of all the electrolytes are markedly temperature-dependent, ranging from 10−8 to 10−10Ω−1 cm−1 at 100°C to 10−2 to 1010Ω−1 cm−1 at 700°C. For solid solutions with the Li4GeO4 structure, conductivities fit the Arrhenius equation over a wide temperature range, but at higher temperatures a change in activation energy occurs, corresponding to a first-order phase transition. In contrast, solid solutions with the Li4SiO4 structure show changes in activation energy which do not correspond to phase transitions, but which appear to indicate changes in the conduction mechanism.

Journal ArticleDOI
TL;DR: In this paper, the study of ionic conduction in fluorides with fluorite type structure leads to new anionic superconductors of formulation Pb1−xBixF2+x (0 ⩽ x⩽ 0.50).

Journal ArticleDOI
TL;DR: Ionic conductivity measurements on LiAlSiO/sub 4/ glass and glass-ceramic showed these materials to be good lithium ion conducting solid electrolytes at high temperatures as discussed by the authors.
Abstract: Ionic conductivity measurements on LiAlSiO/sub 4/ glass and glass-ceramic showed these materials to be good lithium ion conducting solid electrolytes at high temperatures This composition crystallizes in the beta-eucryptite structure which is attractive for solid electrolyte applications because of its low thermal expansion The glasses were prepared by quenching from the melt and were annealed to remove strain The glass-ceramic (beta-eucryptite) samples were crystallized (aided by TiO/sub 2/ and ZrO/sub 2/ nucleating agents) by using a heat treatment determined through differential thermal analysis The conductivity (sigma) was measured (to 650/sup 0/C) with a variety of techniques, including 2-terminal ac, 3-terminal guarded ac, 4-terminal ac, 2-terminal dc, and a pulsed method Vapor-deposited Cr contacts were used Different sample geometries, contact geometries, and measurement circuitries were employed All results are in excellent agreement, and the a-c techniques appear to be the most versatile and accurate of the methods examined In these materials the conductivity is thermally activated (sigma = sigma/sub 0/e/sup -E/kT/) with typical values of sigma/sub 0/ = 19 x 10/sup 2/ (ohm-cm)/sup -1/ and E approximately 068 eV for the glasses, and sigma/sub 0/ = 21 x 10/sup 4/ (ohm-cm)/sup -1/ and E approximately 105 eV for the glass-ceramics Themore » TiO/sub 2/ and ZrO/sub 2/ nucleating agents (concentrations up to 28 mole percent) did not appear to influence the ionic conductivity Data were also taken on a (beta-eucryptite) glass-ceramic with a composition near the beta-eucryptite/beta-spodumene phase boundary The ionic conductivity of this material is lower than that of the LiAlSiO/sub 4/ materials Data are also provided on beta-spodumene material 8 figures, 35 references (auth)« less

Journal ArticleDOI
TL;DR: In this article, self-diffusion coefficients of the oxygen ion in a ThO2 single crystal were determined in the temperature range 845-1646°C by the gas-solid isotopic exchange technique using 18O as a tracer.
Abstract: Self‐diffusion coefficients of the oxygen ion in a ThO2 single crystal were determined in the temperature range 845–1646°C by the gas–solid isotopic exchange technique using 18O as a tracer. The self‐diffusion coefficients determined in the higher temperature range were represented as D=5.73×10−2 exp(−49.9×103/RT) cm2/sec and interpreted to be for intrinsic diffusion due to Frenkel‐type defects. Those determined in the lower temperature range were represented as D=1.00×10−6 exp(−17.6×103/RT) cm2/sec and interpreted for extrinsic diffusion. By using these data, it was elucidated that the charge carrier for ionic conduction in ThO2 was the oxygen ion. Activation energies for oxygen permeation in ThO2 and for oxidation of thorium metal were compared with that for oxygen self‐diffusion in ThO2.

Journal ArticleDOI
TL;DR: In this paper, polycrystalline samples of Li5Al04, Li5Ga04, and Li6Zn04 have been synthesized, and their ionic conductivity measured over a range of temperature.

Journal ArticleDOI
TL;DR: The electrical conductivity of three alkali metal chlorluminates has been investigated from room temperature to above the melting point as mentioned in this paper, and the results show that they have 1.2 × 10 −6, 3.5 × 10−7 and 3.2× 10 −9 omh −1 cm −1, and activation enthalpies are 0.47, 0.46 and 0.53 eV.

Journal ArticleDOI
01 Mar 1976
TL;DR: In this paper, the dielectric behavior of polystyrene aqueous suspensions with low ionic conductivity has been investigated in the frequency range 5 kHz to 30 MHz, and the observed dispersions have been studied as due to the overlapping of two distinct processes, on the basis of the Schwarz-Schurr model.
Abstract: The dielectric behavior of polystyrene aqueous suspensions with low ionic conductivity has been investigated in the frequency range 5 kHz to 30 MHz. The observed dispersions have been studied as due to the overlapping of two distinct processes, on the basis of the Schwarz-Schurr model. The characteristic parameters of the model, as a function of temperature, have been valued.

Journal ArticleDOI
TL;DR: The ionic conductivity of polycrystalline samples of three lithium germanates: Li 4 GeO 4, Li 2 GeO 3, and Li 2 G 7 O 15, has been determined using a c techniques and complex plane analysis as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, high-porosity interpolymer ion exchange membranes have been obtained from poly(styrene sulfonic acid), PSSA and poly(vinylidene fluoride) PVdF using a casting solvent of dimethylformamide and hexamethylphosphoramide.
Abstract: Highly porous interpolymer ion-exchange membranes have been prepared from poly(styrene sulfonic acid), PSSA and poly(vinylidene fluoride) PVdF using a casting solvent of dimethylformamide and hexamethylphosphoramide. The membranes have been characterized by their water content, concentration potential, ionic conductivity, and their hydraulic permeability. An estimation of the porosity of the membranes has been made from the relative conductance of the potassium and the tetrabutylammonium ions in the film. This porosity has been compared with that derived from a consideration of the water flux through a Poiseuille-type pore.


Journal ArticleDOI
TL;DR: The electrical conductivity of sintered specimens of nominally pure thoria and thoria doped with 1-15 mole percent (m/o) CaO was measured between 600/sup 0/ and 1400/sup 1/C in the P/sub 02/ range of 1-10/sup -25/ atm.
Abstract: The electrical conductivity of sintered specimens of nominally pure thoria and thoria doped with 1-15 mole percent (m/o) CaO was measured between 600/sup 0/ and 1400/sup 0/C in the P/sub 02/ range of 1-10/sup -25/ atm. The measured conductivity decreases initially with decreasing P/sub 02/ (mixed conduction region where electron holes and oxygen ions contribute), until it becomes independent of P/sub 02/ (ionic conduction region). The P/sub 02/ corresponding to the transition between these regions is a function of temperature and composition. The variation of conductivity with temperature gives rise to three regions: the high temperature region where the conductivity is attributed to dissociated vacancies, an intermediate temperature range where associated vacancy-impurity complexes dominate, and a low temperature region where grain boundary effects appear to become significant. The activation energy for electrical conduction is a function of composition and P/sub 02/. (7 figures, 31 references)

Journal ArticleDOI
TL;DR: In this paper, the authors measured the conductivity σ of MnF2 and MgF2 single crystals, pure and doped (with Li+, Na+, Y3+, Gd3+), from room temperature to 500°C.

Journal ArticleDOI
TL;DR: In this paper, electrical conductivity and thermogravimetric measurements were made on SrO-doped nonstoichiometric cerium dioxide (i.e., Ce1−ySryO2−y−x) as a function of temperature and oxygen partial pressure.


Journal ArticleDOI
TL;DR: In this article, X-ray diffraction patterns showed that the specimens of Ga2O3K2O = 4, 5, and 6 had a β-alumina type structure.

Journal ArticleDOI
TL;DR: In this article, a pseudo-binary system of Ag2−xAuxSe (0 ⩽ x ⌽ 0.5) is presented, where the ionic and electronic conductivities have about the same value (1 Ω −1 cm −1 ), d.c.
Abstract: The system Ag2−xAuxSe (0 ⩽ x ⩽ 0.5) is pseudo-binary. Two ordered compounds exist at lower temperatures, viz., β-Ag2Se and β-Ag3AuSe2. At higher temperatures a solid solution with the α-Ag2Se (body-centered cubic) structure exists over the whole composition range. The electronic conductivity of the b.c.c. solid solution decreases rapidly with increasing gold content; for x = 0.4 and 0.5 the ionic- and electronic conductivities have about the same value ( 1 Ω −1 cm −1 ), d.c. Polarisation measurements yielded the ionic conductivities and the chemical diffusion coefficient, D . The difference between the mobility of the electrons as measured by the Hall effect and from D is explained by means of a model in which only part of the electrons compensating the change in concentration of the mobile ions during the polarisation and relaxation process are free to move.

Book ChapterDOI
01 Jan 1976
TL;DR: In this article, large scale disorder appears to be an intrinsic process in superionic conductors, where the ionic conductivity is large, in part, because it is proportional to the density of diffusing ions.
Abstract: Superionic conductors1 have been defined as solids with ion conductances exceeding 0.01 ohm−l cm−1. Invariably this occurs because an ion species in the solid begins diffusing away from its normal lattice position. Usually this ion species is one of the major constituents of the solid. Thus in AgI, all of the Ag+ ions are believed to diffuse at high temperature, while the I− stay in position to define a lattice. In CaF2, it is the F− which move. In usual ionic solids, the very small ionic conductivity is provided by impurities or occasional defects. We are interested in a quite different situation—where large scale disorder appears to be an intrinsic process. Thus the ionic conductivity is large, in part, because it is proportional to the density of diffusing ions. This can be very large—of the order of 1022 cm−3

Journal ArticleDOI
E.J. Murphy1
TL;DR: In this paper, a model was proposed to account for these two types of conduction simultaneously, based upon the consideration that ionic conduction in solids depends upon the presence of transient defects in concentration proportional to a Boltzmann factor.

Journal ArticleDOI
TL;DR: In this paper, the effect of the sorbed molecules C 2 H 2, C 6 H 6, CH 3 COCH 3, H 2 O, CH 3 OH,CH 3 OH 2 OH, CHCl 3, butadiene 1,3, cyclohexane, etc. on the electrical conductivity of X zeolites was investigated in the temperature range 150-370°K.