Showing papers on "Ionic conductivity published in 1989"
TL;DR: In this article, a generalized relationship between dopant size and ionic conductivity in binary systems of MO2 oxides was shown, illustrating that the smaller the difference between the dopant ionic radius and the critical dopant radius, the higher the conductivity.
Abstract: Changes in the lattice parameters of fluorite type MO2 oxides (M = Hf4+, Zr4+, Ce4+, Th4+, U4+) due to the formation of solid solutions can be predicted by proposed empirical equations. The equations show the generalized relationship between dopant size and ionic conductivity in the binary systems of these oxides, illustrating that the smaller the difference between the dopant ionic radius and the critical dopant radius, the higher the conductivity. The solubility limit of the same periodic group elements in fluorite-structure MO2 oxides decreaes linearly with the square of Vegard's slope for each solute as determined from the proposed equations.
587 citations
TL;DR: The electrical conductivities of rare earth oxides were investigated in fluorite lattice of ceria at low additive concentrations in this article, where the ionic radii of the added cation were investigated.
405 citations
TL;DR: In this article, the ionic transport number of BaCe 1-x Gd x O 3-X 2 (x=0.10) was studied by measurement of the total conductivity versus P O2 and the EMF of oxygen and hydrogen concentration cells.
208 citations
TL;DR: In this article, the characteristic properties of vitreous electrolytes are summarised for convenience under the three headings of continuity, variability and vulnerability, which cover respectively the tempe, stability and vulnerability.
Abstract: The characteristic properties of vitreous electrolytes are summarised for convenience under the three headings of ‘continuity’, ‘variability’ and ‘vulnerability’. These cover respectively the tempe...
121 citations
TL;DR: In this paper, a thin film of yttria-stabilized zirconia was coated on the fuel side of ceria-samarium oxide disk by the ion plating method.
116 citations
TL;DR: In this article, the structure of LiP and Li 3 P was studied using X-ray diffraction and elemental analysis, showing that LiP has a monoclinic structure and has a black metallic luster.
111 citations
01 Jan 1989
TL;DR: In this paper, the present status of the field of solid state ionics is updated, starting with an overview of recent trends in ionics and concluding with the assessment of future implications.
Abstract: Superionic solids and solid electrolytes are a special group of materials showing high ionic conductivity with tremendous technological potential This book updates the present status of the field Starting with an overview of recent trends in solid state ionics, the book ends with the assessment of future implications Different theoretical, experimental (including NMR), and materials aspects have been covered along with applications Important materials covered include alkali and silver ion conductors, fluorites, Nasicon, heterogeneous solid electrolytes, and glasses The theoretical topics covered in this volume include phenomenological models, fractal techniques, the pre-exponential problem, and fluctuations
86 citations
78 citations
TL;DR: In this paper, an extended glass forming region has been identified in the Li2O:P2O 5:Nb2O5 system, where a high ionic conductivity value ≅2 × 10 −6 Ω −1 cm −1 at room temperature has been found for the composition 60Li 2O:30P 2O5:10Nb 2O 5.
Abstract: An extended glass forming region has been identified in the Li2O:P2O5:Nb2O5 system. Temperature and composition dependence of conductivity have been measured. A high ionic conductivity value ≅2 × 10 −6 Ω −1 cm −1 at room temperature has been found for the composition 60Li2O:30P2O5:10Nb2O5. Conductivity enhancement observed in this ternary system is discussed with reference to glass transition temperature, decoupling index and structural aspects. AC conductivity analysis and dielectric response of the highest conducting composition are described and compared with similar glasses. With the addition of LiF to this glass a conductivity value of 7 × 10 −4 Ω −1 cm −1 at 150° C is observed. The composition is 0.1LiF: 0.9(0.6Li2O:0.3P2O5:0.1Nb2O5). A decomposition potential of 2.7 V has been determined for this electrolyte. The energy density for the cell Li/electrolyte/(TiS2 + 30% electrolyte) has been found to be 108 W-h/kg.
77 citations
TL;DR: Experimental data of nuclear spin relaxation by two-level systems in alkali silicate, borate, and germanate glasses can be described in terms of a microscopic energy barrier impeding ion motion which is significantly different from the activation energy of ionic conductivity.
Abstract: Experimental data of nuclear spin relaxation by two-level systems in alkali silicate, borate, and germanate glasses from 3\ensuremath{\le}T\ensuremath{\le}700 K can be described in terms of a microscopic energy barrier impeding ion motion which is significantly different from the activation energy of ionic conductivity. This description can be understood in terms of the coupling model of conductivity relaxation in glassy ionic conductors.
75 citations
TL;DR: In this paper, the ionic conductivity of ZrO2 doped with 12 mol% Gd2O3, NdO3 or Yb2O 3 was investigated using ac impedance measurement techniques and analysis of frequency-dependent response in the complex plane.
TL;DR: Protonic conductivity of heteropoly compounds (HPC) was studied in this paper in dependence on the degree of hydration and temperature, and it was assumed that ionic conduction of HPC is connected with dynamic intracrystalline dissociation of water molecules and formation of virtual protons.
TL;DR: In this article, the first reason for the use of thin films in battery technology was the low ionic conductivity of the solid electrolyte used; reducing its thickness provided a relatively low internal resistance to the cells.
Abstract: Different technologies allow one to obtain battery materials in the form of thin films. Physical methods, i.e. evaporation or sputtering, and chemical methods, i.e. chemical vapour deposition, are mainly used. Thin film microbatteries have been studied for 30 years. The first reason for the use of thin films in battery technology was the low ionic conductivity of the solid electrolyte used; reducing its thickness provided a relatively low internal resistance to the cells. After this first step concerning mainly the electrolyte, thin film technologies were applied to all the battery elements. Following the miniaturization of electronic devices, thin film solid state batteries are receiving some new attention, motivated by the desire for a battery that can be fully integrated with microcircuits. Lithium microbatteries have been the most studied; while some of them are the replica of “classical” batteries using a liquid elettrolyte, e.g. the Li/TiS 2 system, others use new materials. Very interesting results have been obtained. Because of the very high conductivity of silver conducting electrolytes, silver microbatteries have also been extensively studied and significant results obtained with a primary cell design. Other systems using fluoride or copper as ionic conductor have also been considered; they are characterized by a low available voltage.
TL;DR: In this paper, a comparative study of pure and chromium-doped rutile was performed by means of electrical complex impedance spectroscopy at T = 1273 K for both pure and doped rutsile in the oxygen partial pressure range from 10 −12 to 1 atm.
TL;DR: In this paper, a PEO-NaI system was used to mix polymer solid electrolytes with Nasicon and Al2O3 powders, and an increase of ionic conductivity exceeding 10−1 S/cm at room temperature was observed.
Abstract: Polymer solid electrolytes from a PEO-NaI system were mixed with Nasicon and Al2O3 powders. As a result an increase of ionic conductivity exceeding 10−1 S/cm at room temperature was observed for both cases. This increase was due to a higher concentration of amorphous phase which resulted apparently from a higher nucleation rate during the solidification process. The samples were studied using impedance spectroscopy, X-ray diffraction, electron microscopy, NMR, and other techniques.
TL;DR: In this article, it was shown that most NMR measurements are made in the MHz frequency range and for nearly all glasses this frequency range falls in a region where the ionic conductivity shows a frequency dependence and hence a temperature dependence less than that exhibited by the d.c. or frequency independent conductivity.
Patent•
01 Dec 1989
TL;DR: Polymeric solid electrolytes as discussed by the authors are formed by the present invention, namely, by incorporating a low molecular weight polyethylene glycol, a high molecular weightpolyethylene oxide and an alkali metal or ammonium salt in a specific cinnamate ester compound, followed by a polymerization and crosslinking.
Abstract: Polymeric solid electrolytes are formed by the present invention, namely, by incorporating a low molecular weight polyethylene glycol, a high molecular weight polyethylene oxide and an alkali metal or ammonium salt in a specific cinnamate ester compound, followed by a polymerization and crosslinking. The polymeric solid electrolytes have high ionic conductivity, high strength as a film, and good adhesion with electrodes. Therefore, they can be applied widely as ionics materials, e.g., for the total solidification of lithium batteries and plastic batteries and high capacity condensers and as electrolytes for electrochromic displays.
TL;DR: The ionic conductivity of pressed pellets of dehydrated synthetic analcime, sodalite and offretite was determined by a.c. measurements within the range 10 Hz to 10 MHz as mentioned in this paper.
Abstract: The ionic conductivity of pressed pellets of dehydrated synthetic analcime, sodalite and offretite was determined by a.c. measurements within the range 10 Hz to 10 MHz. The ionic conductivity values of those zeolites exchanged with various monovalent cations were determined by the complex impedance plane method. The conduction activation energies range between 63 and 101 kJ mol−1. Sodium analcime shows the best ionic conductivity, namely 1.8×10−4Ω−1 cm−1 at 400° C. A comparison with the conductivity of other ion-conducting solids was made.
TL;DR: In this paper, direct current and alternating current electrical conductivity measurements were used to determine the activation energies for the formation of oxygen vacancies by breakup of bound defect complexes and their migration at low temperatures.
Abstract: The authors discuss direct current and alternating current electrical conductivity measurements used to determine the activation energies for the formation of oxygen vacancies by breakup of bound defect complexes and their migration at low temperatures (<600{sup 0}C) in Y/sub 2/O/sub 3/-fully-stabilized ZrO/sub 2/ single crystals. The defect clusters break up between 360{sup 0} and 450{sup 0}C.
Journal Article•
TL;DR: In this article, polynuclear indium(III)-hexacyanoferrate(III, II) films were prepared electrochemically on a glassy carbon substrate, and deposition was performed by cycling the potential between 0.85 and 0.0 V vs sce in a fresh 0.5 mM InCl 3 /0.5 M KCl mixture at pH 2.
TL;DR: In this paper, an index known as Image tructural Image npinning Image umber, SUN (S) has been defined for the purpose, based on the unscreened nuclear charge of silver ions and the equilibrium lectronegativities of the halide-oxyanion matrix in these glasses.
TL;DR: In this article, the morphological organization and mesogenic behavior of PEO with organo-alkali salts, such as sodium phenolates and naphtholates, are discussed.
Abstract: Recent work on the crystallographic and morphological structure of semicrystalline PEO complexes with alkali metal salts is described. The thermal properties of the materials and the influence of solvent on complex formation is also considered. The dependence of the ionic conductivity of the complexes on their morphology, the temperature and ionic association is discussed and some current work relating to the mechanism of conduction is considered. The various strategies which have been adopted to suppress crystallinity and so to optimize ionic conductivity, including networks, “comb” structures, and linear copolymers, are reviewed. The morphological organization and mesogenic behavior of some novel crystalline complexes of PEO with organo-alkali salts, such as sodium phenolates and naphtholates, are discussed. Some PEO composite materials which have mixed electronic-ionic mechanisms of conductivity are also described.
TL;DR: In this article, the formation and stability of the phases CaZrO3 and CZr4O9 in calciastabilized zirconia were investigated.
TL;DR: In this article, the tin ion exchanged into the mordenites with up to 3.6 molecules per unit cell was measured in atmospheres with different water partial pressures, and the conductivity increased with increasing tin content until full ion exchange whereafter it remained virtually constant.
TL;DR: In this paper, fast ion conductors based on Li 1−x M 2 −x M−xM′ x P 3 O 12 (M = Hf, Zr; M′ = Ti, Nb) structures have been synthesized and the electrical transport properties are studied to determine their ionic conductivities.
TL;DR: In this paper, the transient ionic current in a ferroelectric liquid crystal (FLC) cell was measured as a function of applied voltage at different temperatures, and the measured current shows a delay peak which decays rapidly to a steady-state value.
Abstract: The transient ionic current in a ferroelectric liquid crystal (FLC) cell was measured as a function of applied voltage at different temperatures. The measured current shows a delay peak which decays rapidly to a steady-state value. The steady-state current exhibits a thermal activated behavior with an activation energy of 0.94 eV, and depends exponentially on the square root of the field strength similar to the Schottky effect. To describe the transport behaviors of the ions, a model with ionization-recombination equations which include a field-dependent ionization coefficient, and a continuity equation for the accumulated surface charges has been introduced. According to the model, the current decay time and the peak position of the delay peak current can be used to determine the ion mobility. Two ionized species have been identified in the FLC medium: a weakly ionized species with a relatively constant mobility of 2.0×10-7 cm2/Vs, and a highly ionized species with a room temperature mobility of 4.1×10-7 cm2/Vs and a thermal activation energy of about 0.71 eV. Detailed calculation of the ionic current and comparison with experimental results are given.
TL;DR: In this paper, the changes in Raman spectra and ionic conductivity in some glasses in silicate, borate and phosphate systems have been studied, and it has been shown that the conductivity of the glass was mainly dependent on the total number of active ions Li + or Na +, but there was also an effect of the structure on conductivity.
Abstract: In the past few years, studies of the changes in Raman spectra and ionic conductivity in some glasses in silicate, borate and phosphate systems showed that the ionic conductivity of the glass was mainly dependent on the total number of active ions Li + or Na + , but there was also an effect of the glass structure on conductivity. When Al 3+ and/or B 3+ ions were present in the glass in the form of AlO 4 and BO 4 and the excess negative charge on them was compensated by the active cation ion, the glass would have higher ionic conductivity. A detailed investigation of the Raman spectra of Li 2 OB 2 O 3 P 2 O 5 glasses has shown that besides phosphate groups, such as metaphosphate (PO 3 ) n n − , tetraphosphate (P 4 O 13 ) 6− , triphosphate (P 3 O 10 ) 5− and pyrophosphate (P 2 O 7 ) 4− ,a nd borate groups, such as diborate (B 4 O 7 ) 2− and chain-type metaborate (BO 2 ) − , there may also be different of kinds of phosphate groups containing BO 4 units, (BOP) 0 and (BOP) − , groups present in this glass system. The active ability of Li + ions present in (B 4 O 7 ) 2– , phosphate groups with BO 4 units and BO 4 units and (BOP) − groups is higher than those present in various phosphate groups with non-bridging oxygen(s).