Showing papers on "Ionic conductivity published in 1977"
TL;DR: In this paper, Li ionic conductivity of Czochralski−grown Li3N single crystals using electrochemical transport measurements is reported. But the results are not comparable with the best data reported for Li β−alumina single crystals.
Abstract: Lithium ionic conductivity of Czochralski‐grown Li3N single crystals using electrochemical transport measurements is reported. The highest Li ionic conductivity was found perpendicular to the hexagonal c axis, the anisotropy decreasing from two to one decade between 20 and 200 °C. Ambient Li ionic conductivity parallel to the Li2N planes of the layer structure was found to be σ=10−3 Ω−1 cm−1 with an activation energy of 0.25 eV. These values are comparable with the best data reported for Li β‐alumina single crystals.
377 citations
TL;DR: In this article, Li ion conductivity in solid solutions formed between and has been measured as a function of temperature and composition using a • c technique, and the highest conductivities were found at 50 and 60 mole percent (m/o) phosphate.
Abstract: Lithium ion conductivity in solid solutions formed between and has been measured as a function of temperature and composition using a‐c techniques. Highest conductivities were found at 50 and 60 mole percent (m/o) phosphate. Empirical conductivity parameters are presented and qualitatively analyzed in terms of structural and compositional effects. Unit cell parameters have been determined across the entire range of solid solution by x‐ray powder diffraction.
192 citations
TL;DR: The galvanostatic intermittent titration technique (GITT) has been used to electrochemically determine the chemical and component diffusion coefficients, the electrical and general lithium mobilities, the partial lithium ionic conductivity, the parabolic tarnishing rate constant, and the thermodynamic enhancement factor in Li 3 Sb and Li 3 Bi as a function of stoichiometry in the temperature range from 360 to 600°C as mentioned in this paper.
145 citations
TL;DR: In this article, conductivity data for several new lithium ion conductors are presented, which indicate that the conductivity can be improved by suitable doping, as well as stoichiometric control.
131 citations
TL;DR: In this article, the crystal sturcture of the high temperature modifications have been determined be elastic neutron scattering experiments on powdered samples, which can be summarized as follows: on the basis of these structural data, the different behavior of the ionic conductivity of CuI and CuBr at high temperature can be understood.
109 citations
85 citations
TL;DR: In this article, it was shown that crystal water not only provides a high ionic conductivity which is conditional for a fast electrochromic reaction but also stabilises electrocatalytically active surface sites for fast hydrogen or Li exchange with the adjacent electrolyte.
Abstract: WO3 films prepared under different conditions (evaporation, reactive sputtering and spraying of aqueous solutions of metatungstic acid) differ by orders of magnitude in their electrochromic sensitivity. Diffuse X-ray studies show the evaporated and sputtered films to be amorphous and to consists of a disordered network of corner sharing WO6 octahedra. Sprayed films have different degrees of crystallinity depending on spraying conditions. From differential scanning calorimetry we conclude that the crystal water present in most films strongly affects the local order of the corner sharing octahedra. We find that crystal water not only provides a high ionic conductivity which is conditional for a fast electrochromic reaction but also stabilises electrocatalytically active surface sites for fast hydrogen or Li exchange with the adjacent electrolyte.
80 citations
76 citations
TL;DR: In this article, a phenomenological introduction to the important physical parameters involved in ionic conduction in solids is followed by order of magnitude estimates of these quantities for materials which can be considered to be fast ion conductors.
Abstract: A brief phenomenological introduction to the important physical parameters involved in ionic conduction in solids is followed by order of magnitude estimates of these quantities for materials which can be considered to be fast ion conductors. Experimental techniques are outlined, and a comprehensive compilation of currently available data on fast ion conductors is presented. The conductivity and diffusion data are coupled with additional criteria to indicate broad classes of materials which may show enhanced ion conductivity.
75 citations
TL;DR: In this article, the electrical conductivities of tysonite-type fluorides based on in the sintered state were measured for various aliovalent cation dopants.
Abstract: The electrical conductivities of the tysonite‐type fluorides based on in the sintered state were measured for various aliovalent cation dopants. Doping of difluoride such as , , or up to 5 mole percent made the conductivity increase while the doping of tetrafluoride such as led it to decrease. These facts together with the experimental results of electrolysis indicated that the specimens were fluoride ion conductors resulting from the easy movement of fluoride ion vacancies. The activation energies for conduction at the high temperature range above 250°C were, in general, about 0.25 eV irrespective of divalent dopant species, while those at lower temperatures were depending on the dopant species. Their conductivities are, in general, higher than those of the electrolytes which are also the tysonite‐type fluorides. had the highest conductivity among the tysonite‐type fluorides ever examined.
73 citations
TL;DR: In this paper, the authors reported measurements of the electrical conductivity and 19F nuclear magnetic resonance (NMR) relaxation times T1, T2, T1 rho and T1D in BaF2 single crystals over a temperature range 300K-1200K.
Abstract: Reports measurements of the electrical conductivity and 19F nuclear magnetic resonance (NMR) relaxation times T1, T2, T1 rho and T1D in BaF2 single crystals over a temperature range 300K-1200K The dominant process responsible for the 19F spin relaxation is self-diffusion The magnitude and temperature dependence of the relaxation times are satisfactorily interpreted using the Wolf theory Absolute values of diffusion coefficients calculated from NMR relaxation data assuming a vacancy diffusion process are in excellent agreement (within 15%) with those calculated from ionic conductivity data using the Nernst-Einstein relation From the temperature dependence studies, the diffusion parameters were determined The formation enthalpy for a Frenkel pair was found to be 191 eV and migration enthalpies for free F- vacancies and F- interstitialcies were found to be 057 and 076 eV respectively
TL;DR: In this paper, the electrical conductivity of lithium chloroaluminate has been investigated in the temperature range between room temperature and 180°C, with an activation enthalpy of 047 eV A−C.
Abstract: The electrical conductivity of lithium chloroaluminate has been investigated in the temperature range between room temperature and 180°C It is molten above 145°C The conduction is practically purely ionic and is attributed to the transport of lithium ions The experiments show high values for ionic conductivity in the solid state, only exceeded by Li‐β‐alumina and some LiI‐based materials At 25°C the conductivity was found to be , with an activation enthalpy for of 047 eV A‐C conductivity measurements were influenced by sample preparation and cell arrangement The ionic conductivities of this and several other newly found lithium ionic conductors, as well as those previously known, are compared in the temperature range between 20° and 250°C
TL;DR: In this paper, a galvanic cell was used to measure the conductivity, thermoelectric power, and Hall coefficient of the cell, and the phase diagrams were constructed front these results, especially from E vs T plots.
Abstract: Using the galvanic cell Cu|CuBr·C 6 H 12 N 4 CH 3 Br|Cu 2-δ VI|Pt, the deviation δ from the stoichiometric composition is varied up to 0.2 for Cu 2-δ Se, Cu 2-δ S and their alloys. Electronic conductivity, thermoelectric power and Hall coefficient are measured as functions of e.m.f. of the cell, E , and of temperature, T , (20°C∼200°C). The phase diagrams are constructed front these results, especially from E vs T plots, and the electrical properties arc interpreted by the use of a simple model. Further, the ionic conductivity is measured with the use of the cell in low temperature phase as well as in high temperature one. The value of E seems not to represent the Fermi kinetic energy even in the high temperature phase having the average structure. This is because of the largeness of δ, and can be interpreted as being due to the screening effect of carriers (holes) on copper ion vacancies.
TL;DR: In this paper, experimental evidence for one-dimensional ionic conductivity in β-Eucryptite (LiAlSiO 4 ) by electrochemical transport measurements is presented.
TL;DR: In this article, the glass-forming region and the glass transition temperature in the system Agl-Ag/sub 2/O-MoO/sub 3/ are presented.
Abstract: The glass-forming region and the glass transition temperature (T/sub g/) in the system Agl-Ag/sub 2/O-MoO/sub 3/ are presented.
TL;DR: In this paper, a quarts-like structure with Li + -ions arranged in structure main channels parallel to the cyrstallographic c-axis has been proposed for β-Eucryptite (LiAlSiO 4 ).
TL;DR: In this article, the ionic conductivity and thermal properties of Li5AlO4 and LiOH have been measured in both wet and dry environments, and it was shown that an endothermic reaction at ∼ 415°C and an associated large increase in conductivity is observed both in Li 5AlO 4 in a wet environment and in LiOH.
TL;DR: The self-diffusion coefficient D of silver ions in α-Ag 2 Te has been measured by the tracer technique using Ag 110m and the mobility µ of cations is estimated from the ionic conductivity σ.
Abstract: The self-diffusion coefficient D of silver ions in α-Ag 2 Te has been measured by the tracer technique using Ag 110m and the mobility µ of cations is estimated from the ionic conductivity σ. The ratio µ/ D is slightly deviated from the Einstein relation. This deviation is discussed in comparison with a theory appropriated to the average crystals proposed by Yokota.
TL;DR: In this paper, both the electronic and ionic conductivity of potassium ferrite (K1+xFe11O17) have been measured at 580°K as a function of x and the coupling between the two fluxes is shown to be very small.
TL;DR: The structure of isotypic Na 5 YSi 4 O 12 is characterized by Si 12 O 36 rings stacked to form columns held apart by MO 6 octahedra.
TL;DR: In this article, solid electrolytes with high copper ionic conductivity and low electronic hole conductivity were found in the RbCl + CuCl system, and the conductivity was measured as functions of temperature and composition.
Abstract: Solid electrolytes with high copper ionic conductivity and low electronic hole conductivity were found in the RbCl + CuCl system. The highest conductivity of RbCu/sub 3/Cl/sub 4/ (75 mole percent (m/o) CuCl) was 2.25 x 10/sup -3/ (..cap omega..-cm)/sup -1/ at 25/sup 0/C. The conductivity was measured as functions of temperature and of composition. X-ray patterns and thermal analyses indicate that the material is a new compound and not a mixture of the constituents. 6 figures, 2 tables.
TL;DR: Ionic and electronic conductivity has been measured in this article, where Ionic conductivity increases abruptly at ∼170°C to ∼1 (Ω−cm)−1, and a transition at this temperature was observed by DSC.
Abstract: Ionic and electronic conductivity has been measured in and. Ionic conductivity was measured by using as a blocking electrode for electronic conduction. Transference numbers were confirmed by cells of the type . Ionic conductivities were for and , respectively, at room temperature. The conductivity of increases abruptly at ∼170°C to ∼1 (Ω‐cm)−1. A transition at this temperature was observed by DSC.
PARC1
TL;DR: An anomalous increase in the NMR relaxation rates of the copper and iodine nuclei in CuI has been observed as the insulator-to-superionic conductor phase transition is approached as mentioned in this paper.
TL;DR: In this article, the authors examined ionic equilibrium, Li+ transport, ionic conductivity, and stability of Li+-Ni+ beta alumina, showing that Li+ ions migrate through the solid electrolyte lattice without significantly altering its Na+ content.
TL;DR: In this paper, the a.c. impedance of single crystal specimens of β-PbF2 has been studied as a function of frequency and temperature in the range 10−2 to 105 Hz and 25 to 320°C.
TL;DR: In this article, the Schottky vacancy pair formation and the energy of a positive ion vacancy for migration and for the association with a divalent cation impurity were obtained from the ionic conductivity curve.
Abstract: Ionic conductivity of LiH crystal has been measured. The energy for Schottky vacancy pair formation (2.3±0.3 eV) and energies of a positive ion vacancy for migration and for the association with a divalent cation impurity (0.54 eV and 0.50 eV, respectively) were obtained from the ionic conductivity curve. The energy for the rotation of a vacancy around divalent cation was 0.38±0.02 eV from the measurements of ionic thermocurrent (ITC). Photoconductivity peaks at 5.05 eV and 6.7 eV are ascribed to the exciton and to the photoemission state, respectively. It is suggested that the defect properties of LiH are similar to those of LiCl and LiF and that the electronic properties are close to those of LiI.