Showing papers on "Ionic conductivity published in 1988"

Oxygen ion conductivity of the ceria-samarium oxide system with fluorite structure

Abstract: Ionic conduction of oxygen in the ceria-samarium oxide system was investigated as a function of temperature, partial pressure of oxygen and the oxide composition, together with its crystal structure, density and defect structure. The ionic conductivity of (CeO2)1−x(SmO1.5)x was the highest in ZrO2-, ThO2- and CeO2-based oxide systems. The system CeO2-SmO1.5 consisted of the solid solution with a fluorite structure atx<50 at.%. The ionic transference number was nearly unity between 600 and 900°C. With an increase in Sm2O3 content, the ionic conductivity gradually decreased due to a decrease in mobility of oxygen ions. The samarium oxide-doped ceria was less reducible than pure and alkaline earth oxide-doped ceria.

Radiation cured solid electrolytes and electrochemical devices employing the same

Abstract: A method for forming an interpenetrating polymeric network containing a liquid electrolyte for use in solid state electrochemical cells which comprises forming a mixture of a liquid monomeric or prepolymeric radiation polymerizable, compound, a radiation inert ionically conducting liquid, and an ionizable alkaline metal salt; subjecting said mixture to actinic radiation to thereby crosslink said radiation polymerizable ionically conducting material and form a solid matrix containing said ionically conducting liquid; and electrode half elements and electrochemical cells incorporating said network.

Electrical properties and microstructure in the system ceria-alkaline earth oxide

Abstract: The ionic conduction of oxygen in the ceria-alkaline earth oxide system was investigated as a function of temperature, partial pressure of oxygen and oxide composition, together with its crystal structure, density, and microstructure. Undoped ceria and its solid solution with alkaline earth oxides have a cubic fluorite structure. The ionic conductivity of ceria is greatly enhanced by additions of calcia and strontia, even when they are added in excess of the solubility limit. The conductivities of ceria-calcia and ceria-strontia were much higher than those of calcia-and yttria-stabilized zirconia. Up to the limit of calcia and strontia, the ionic transference number was nearly unity in the temperature range between 600 and 900°C. With an increase in calcia and strontia content, the ionic conductivity was little affected by the presence of a second phase of CaO and SrCeO3.

Ionic conductivity of polymer electrolytes and future applications.

Abstract: La dissociation ionique dans les polymeres se produit par interaction des ions avec les groupes polaires des polymeres qui sont lies par liaison covalente. Application dans les appareillages electrochimiques solides

Single-ion conduction in poly[(oligo(oxyethylene)methacrylate)-co-(alkali-metal methacrylates)]

Abstract: Preparation de couches minces a partir de solution methanolique de l'oligomere et de methacrylate alcalin par coulee et polymerisation sur une plaque de Teflon sous azote

Ionic conductivity of organosulfur melts for advanced storage electrodes

Abstract: Organosulfur melts show promise as positive electrodes for advanced storage batteries. The attainable energy efficiency and power density of a secondary battery is directly related to polarization losses in the cell under load. One of the contributing factors to polarization of an organosulfur electrode is the rate of ionic transport in the melt. Among the sodium/organosulfur batteries under investigation in this laboratory is the sodium/beta"‐alumina/(tetraethylthiuram disulfide) cell, in which the product of cell discharge is the thiolate salt, sodium diethyldithiocarbamate (NaDEDC). Accordingly, the ionic conductivity of NaDEDC and related electrolytes in molten tetraethylthiuram disulfide (TETD) has been studied as a function of composition and temperature. The ionic conductivity of a NaDEDC/TETD melt of composition corresponding to 2% discharge of a Na/TETD battery was determined to be at 130°C which increases to for a melt corresponding to 28% discharge. The discharge data for Na/TETD batteries indicates that ionic conductivity of the positive electrode melt contributes negligible polarization after a few percent of cell discharge, indicating that ionic conductivity in the above range is acceptable for energy‐efficient operation of these cells over nearly the entire compositional domain. The relationship between the equivalent conductivity of these melts and concentration is also discussed, as well as the implications of the measured viscosity of the pure TETD melt.

Solid State Electrochemistry and Its Applications to Sensors and Electronic Devices

Abstract: 1. Introduction. 2. Ionic and Electronic Conduction of Solid and Liquid Oxides and of Other Ionic Compounds. 3. Relation between the Conductivity and Diffusivity of Ions in Oxides. 4. Diffusion of Ions in Solid and Liquid Oxides. 5. Transport Properties in Oxides with Multicomponents. 6. Equilibrium Electromotive Force of Galvanic Cells with Solid Electrolytes of Oxygen Anion Conduction. 7. Galvanic Cells with Electrolytes with Non-Oxygen Conduction. 8. Overpotential at Interface between a Metal and an Oxide with Ionic Conduction. 9. Electrochemical Kinetics at the Interface between Metals and Liquid Oxides with Ionic Conduction. 10. Industrial Application of Oxygen Sensors with Solid Electrolytes of Oxygen Anion Conduction. 11. Solid-Oxide Oxygen Sensors for the Steelmaking Industry. 12. Various Chemical Sensors with Solid Oxides. 13. Various Oxides used for Electronic Devices. Appendix. Subject Index.

Structure and ionic conductivity of LiCl-Li2O-TeO2 glasses

Abstract: The structure and the ionic conductivity of the ternary LiClLi 2 OTeO 2 glasses were investigated. The structure was studied mainly by means of IR spectroscopy. It was observed that the TeO ax bond, where ax stands axial position of the TeO 4 trigonal bipyramid, became weaker with increasing the LiCl content in binary LiClTeO 2 glasses, indicating that LiCl works as a network modifier. On the other hand, the gradual increase in the wave number of the peak due to the TeO ax bond was observed when Li 2 O was replaced with LiCl. This was explained in terms of a difference in bonding characteristics between TeO eq and TeCl eq bonds, where eq denotes the equatorial position. The electrical conductivity of the glasses with a high concentration of Li + ion reached an order of 10 −6 S cm −1 at 25° C. This value was comparable to those of the other fast Li + ion conducting glasses such as LiClLi 2 OB 2 O 3 and LiPO 3 LiCl systems. The composition dependence of the electrical conductivity was discussed in relation to the glass structure, especially in terms of bonding characteristics of TeCl and TeO.

Synthesis, NMR characterization, and electrical properties of siloxane-based polymer electrolytes

Abstract: : A crosslinked siloxane-based polymer has been prepared by the reaction of Poly(methylhudrosiloxane), monomethyl ether poly(ethylene glycol), and poly(ethylene glycol). The polymer, which has been structurally characterized by 29 Si NMR, forms complexes with LISO CF3 that exhibit good ionic conductivities (for a LiSO3CF3 15 wt% complex). The polymer and its salt complexes have been characterized by elemental analysis, 29 Si NMR powder diffraction X-ray powder diffraction, DSC, and AC complex impedance spectroscopy. The dependence of the ionic conductivity was investigated as a function of temperature, salt concentration (91 wt % to 25 wt %), and alkali metal cation (Li, Na, K, Rb, and Cs). Keywords: Polysiloxane, Polyethylene glycol, Copolymers, Polymer electrolytes, Polymer salt complexes, Ionic conductivity.

Structural and dynamical correlations in Ag2Se: A molecular dynamics study of superionic and molten phases

Abstract: We study the structural properties, single‐particle dynamics, and the charge transport in superionic and molten Ag2Se using the method of molecular dynamics. The calculations are based on a model of interionic potentials in which the ions interact through Coulomb interaction, steric repulsion, and charge–dipole interaction due to the large electronic polarizability of the selenium ions. In the superionic phase the Ag ions diffuse through a stable bcc lattice of Se atoms. Structural and dynamical correlations are studied at five temperatures in the superionic phase and three temperatures in the molten phase. Among the structural correlations the results are presented for partial pair distribution functions, coordination numbers, partial structure factors, bond angle distributions, and the wave vector and temperature dependence of the Bragg intensities. Detailed comparison with the neutron and x‐ray single crystal diffraction results are made whenever possible. Diffuse neutron and x‐ray scattering is calcul...

Diffusion path and Haven’s ratio of mobile ions in α - Ag 2 Te

Abstract: A molecular-dynamics method is applied in a study of silver diffusion in superionic conductor ${\mathrm{Ag}}_{2}$Te for several temperatures with use of effective pairwise potentials. The static and dynamical structures are calculated. The density distribution map of silver ions suggests that a Ag ion, located at a tetrahedral site for most of the time, moves to a neighboring tetrahedral site via the vicinity of an octahedral site---a result which is consistent with the explanation of Haven's ratio proposed by Okazaki. The activation energy for a ionic diffusion also is obtained from the Arrhenius plotting of the self-diffusion coefficient of ${\mathrm{Ag}}^{+}$.

Ionic conductivity in mixtures of salts with comb‐shaped polymers based on ethylene oxide macromers

Abstract: Preparation du polymere a partir d'un ether vinylique comprenant trois unites oxyethylene avec un groupe terminal methoxy

Model for the Electrical Conductivity of Reduced Stabilized Zirconia

Abstract: The electrical conductivity of electrochemically reduced samples of stabilized zirconia has been measured by impedance spectroscopy, in the range 500–1000 K. Two different conduction processes are involved depending on the deviation from stoichiometry. For small deviations from stoichiometry, the total electrical conductivity increases only slightly. On the other hand, a large increase in the electrical conductivity is observed when the departure from stoichiometry is high. This is interpreted in terms of an increase in the ionic conductivity due to a variation of the dielectric constant and a high electronic conductivity for large deviations from stoichiometry. The variation of this electronic conductivity is more complex than observed in ceria‐based materials.

Lithium ion conducting glasses in the system LiClLi2OP2O5SiO2

Abstract: Glasses with good ionic conductivity of lithium ions have been prepared in the LiClLi2OSiO2P2O5 system. The SiO2/P2O5 ratio was kept at 1 5 and it was found that below 1200°C, this leads to a Li2O/P2O5 ratio of about two for the glasses formed. The structure of the glasses appears to be composed of linear chains of phosphate polymers. The highest ionic conductivity is observed in the composition 0.25LiCl0.48Li2O0.03SiO20.24P2O5 with σ = 2.5 × 10−3 (Ω-cm)−1 and Ea = 0.54 eV (52 kJ/mol) at 235°C. The conductivity increases, the activation energy and the glass transition temperature decrease with increasing LiCl content. Results of the ionic conductivity, FTIR, and DSC measurements are discussed in terms of composition and structural properties of the chloride glasses, and are compared with those of the corresponding oxide glasses.