Showing papers on "Ionic conductivity published in 1984"
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01 Jan 1984
TL;DR: In this paper, the authors present a detailed description of the properties of solid state chemistry, including point groups, space groups, and crystal structure, as well as some factors which influence crystal structure.
Abstract: What is Solid State Chemistry? Preparative Methods. Characterization of Inorganic Solids: Application of Physical Techniques. Thermal Analysis. X-ray Diffraction. Point Groups, Space Groups and Crystal Structure. Descriptive Crystal Chemistry. Some Factors Which Influence Crystal Structure. Crystal Defects and Non-Stoichiometry. Solid Solutions. Interpretation of Phase Diagrams. Phase Transitions. Ionic Conductivity and Solid Electrolytes. Electronic Properties and Band Theory: Metals, Semiconductors, Inorganic Solids, Colour. Other Electrical Properties. Magnetic Properties. Optical Properties: Luminescence, Lasers. Glass. Cement and Concrete. Refractories. Organic Solid State Chemistry. Appendixes. Index.
2,106 citations
TL;DR: In this paper, the defect structure of these materials and the resulting transport properties (electrical conductivity, diffusion and transference number) are discussed as a function of temperature, oxygen partial pressure and composition.
278 citations
TL;DR: In this paper, a phase transition of Li 3 PS 4 has been revealed at 190°C both by DTA and by a discontinuity in the Arrhenius plots of conductivity.
274 citations
TL;DR: In this article, a method for the extraction of d.c. conductivities, hopping rates and for estimating carrier concentration effects is described for three different types of material, single-crystal LiGaO2, β″-alumina and Na/Ag β alumina.
Abstract: Over a wide range of frequencies, the a.c. conductivity of ionic materials shows two regions of frequency-dependent conductivity. These are each characterized by a term Kω
p
1−
ω
n where K, n are constants, ω
p is a fundamental frequency identified with the hopping rate and ω is the measuring frequency. This behaviour is an example of Jonscher's Law of Dielectric Response for ionic conductors. In many cases, the region of low-frequency dispersion approximates to a frequency-independent plateau which may be taken as the d.c. conductivity. In others, a significant low-frequency dispersion is present and cannot be ignored in determining the effective d.c. conductivity. A method for the extraction of d.c. conductivities, hopping rates and for estimating carrier concentration effects is described. Data for three different types of material, single-crystal LiGaO2, β″-alumina and Na/Ag β-alumina are used to illustrate the method.
224 citations
163 citations
TL;DR: In this paper, a copolymere par polycondensation de dimethyldichlorosilane avec le mono-, di-, tetra-, ou nonaethyleneglycol was presented.
Abstract: Preparation du copolymere par polycondensation de dimethyldichlorosilane avec le mono-, di-, tetra-, ou nonaethyleneglycol
155 citations
TL;DR: In this paper, the conductivity of polycrystalline Y2O3-ZrO2 samples has been studied by complex impedance and four-probe direct current techniques.
Abstract: The conductivity of several single crystal and polycrystalline Y2O3-ZrO2 samples has been studied by complex impedance and four-probe direct current techniques. For single crystals only one arc, due to lattice conductivity, was observed in the complex impedance representation. Polycrystalline materials showed a second arc, due to grain boundary resistance, the extent of which decreased as the impurity concentration was reduced and as the electrolyte microstructure improved. The activation energies for the volume and total conductivity of the purest polycrystalline samples were similar and agreed with those for the single crystals. These values, however, decreased by 20 to 25 kJ mol−1 on going from low ( 850° C) temperatures. The change in the activation energy with temperature is thought to be due to a gradual transition between an association region, where vacancies are bound to dopant cations, and a dissociation region where vacancies are free and mobile.
147 citations
TL;DR: Ionic conductivity results for LiSO3CF3 complexes with two amorphous poly(methoxy polyethylene glycol monomethacrylates) (PEM) were determined and values as high as ∼6 × 10 −4 Ω −1 cm −1 at 373 K and ∼2 × 10−5 Ω−1 cm−1 at 293 K.
115 citations
TL;DR: In this paper, the Ionic conductivity of phases with general formulaLi x Ln 1/3 Nb 1− x Ti x O 3 (Ln =La, Nd) has been determined for materials with a small value of x, i.e., in composition range with a Ln1/3 nbO 3 perovskite related structure.
104 citations
90 citations
TL;DR: In this paper, an extensive survey of many glass systems including silicates, borates, etc., was conducted with the aim of selecting suitable electrolytes for use in Na/S cells operating around 350°C.
TL;DR: In this paper, a conductivity vs temperature relationship is derived which results from simplified geometrical considerations of a polycrystalline solid electrolyte, assuming that oxygen ion diffusion only takes place through the grains or along the grain boundaries.
TL;DR: In this article, the electrical conductivity and oxide ion transference number of praseodymia doped ceria systems were measured, and the former increased rapidly with the prasodymia content, while the latter decreased.
Abstract: The electrical conductivity (σ) and oxide ion transference number (t
0) of praseodymia doped ceria systems were measured. The former increased rapidly with the praseodymia content, while the latter decreased. At 600° C, for instance,σ CeO2 and Ce0.6Pr0.4O2 under 0.21 atm of oxygen were 2.0×10−5 and 3.6×10−2 S cm−1; andt
0 in them were 0.59 and 0.11, respectively. This mixed conductor having high electrical conductivity might be useful as a fuel cell electrode if it could be combined with a suitable solid electrolyte.
TL;DR: In this article, the temperature dependences of conductivity CsHSO4, CsHSeO4 and RbHSEO4 have been measured and optical investigation was also made.
Abstract: The temperature dependences of the conductivity CsHSO4, CsHSeO4, RbHSO4, RbHSEO4, and NH4HSO4 have been measured and optical investigation was also made. It was found that the high temperature phase transitions in CsHSO4, CsHSeO4, and RbHSeO4 at 413, 400 and 446 K, respectively are the transitions to the superionic state with 6′7 10−30hm−1.cm−1. Some pecularities of these phase transitions are reported.
TL;DR: The relation entre les caracteristiques moleculaires and la conductivite electrique of ces complexes is discussed in this article. But the relation between the temperature and the conductivité is not discussed.
Abstract: Relation entre les caracteristiques moleculaires et la conductivite electrique de ces complexes. Influence des caracteristiques moleculaires sur la relation entre la temperature et la conductivite
TL;DR: Relation entre les caracteristiques moleculaires and l'influence de la temperature sur la conductivite is discussed in this article, where the authors also consider the influence of the temperature on the conductivité.
Abstract: Relation entre les caracteristiques moleculaires et l'influence de la temperature sur la conductivite
TL;DR: In this article, the ionic conductivity of single crystals of tysonite-type solid solutions La 1− x Ba x F 3− x (0⩽ x ⩽0.095) has been studied parallel and perpendicular to the crystallographic c axis in the temperature range 293-1300 K.
TL;DR: In this article, the ionic conductivity, the stability of the material and the densification during sintering have been considered in relation to the nature and level of a range of dopants described in the literature.
Abstract: The crystal structures of the β-alumina compositions have been described and used to explain the fast ion transport for which these materials are renowned. Measured values of both the single crystal and polycrystalline ionic conductivity show a wide variation; this is explained in terms of the range of chemical compositions of the β-alumina system and also the variety of measuring techniques used. Dopants or impurity ions can have a significant effect on the physical properties of the β-aluminas. The ionic conductivity, the stability of the material and the densification during sintering have been considered in relation to the nature and level of a range of dopants described in the literature. The optimization of the ionic and mechanical properties has been achieved by development of the fabrication techniques and it is this which accounts for much of the present research. Thus the many different methods of producing both single and polycrystalline material have been described, including the range of sintering routes currently available. The advantages and disadvantages of each production route in terms of the resulting properties have also been discussed.
TL;DR: Aqueous suspensions of delaminated zirconium phosphate have been recently obtained in this article by a suitable intercalation-deintercalation of alkylamines.
TL;DR: In this paper, the authors measured the conductivity of the chloride ion in anhydrous, plasticized, quaternary ammonium polymer solid electrolytes and found that the conductivities range from 7 x 001 to 3 x 10 to the minus 4th power/ohms/cm depending on the plasticizer level and temperature.
Abstract: : Chloride ion conductivity in anhydrous, plasticized, quaternary ammonium polymer solid electrolytes is studied Curved plots of 1n(sigma T) vs 1/T indicate that transport of ions in these materials may be described by WLF-type equations AC complex impedance measurements for the ranges 5 Hz-500 kHz and 26-98 C with ion-blocking Pt electrodes and ion-reversible calomel electrodes show that the chloride ion is mobile Conductivities measured range from 7 x 001 to 3 x 10 to the minus 4th power/ohms/cm depending on the plasticizer level and temperature
TL;DR: In this paper, the parameters of ionic and electronic disorder in polycrystalline materials are analyzed and the energy level positions for various dopants are given. But it is not known which ionic disorder mechanism is dominant.
TL;DR: In this paper, four classes of solid ionic conductors are distinguished: ion exchangers, electrolytes, electrodes, and chemical stores, and the most important parameters for the synthetic chemist are the factors that govern the activation enthalpy.
Abstract: Four classes of solid ionic conductors may be distinguished: (a) ion exchangers, (b) electrolytes, (c) electrodes, and (d) chemical stores. Each has important applications with different fabrication requirements. Fast ion transport is required in electric-power applications, and various strategies are discussed for power batteries. The design of new materials begins with a theoretical model for ionic transport; the situation in stoichiometric compounds is compared with that in doped compounds, and electrolytes are contrasted with mixed ionic-electronic conductors. The most significant parameters for the synthetic chemist are the factors that govern the activation enthalpy $\Delta$H$\_m$ for diffusion, the concentration c of mobile carriers, and the temperature T$\_t$ for any phase transition from a normal to a fast ionic conductor. Strategies for decreasing $\Delta$H$\_m$ and increasing c prove to be ion-specific, and the most successful strategies for each mobile ion are presented. The origin of a T$\_t$ in stoichiometric compounds and the distinction between smooth and first-order transitions are also considered.
TL;DR: A review of high-pressure studies of ionic conductivity in solids can be found in this paper, where the authors present a brief theoretical background with some of the concepts and results necessary for the analysis and interpretation.
Abstract: Publisher Summary The chapter presents a discussion on high-pressure studies of ionic conductivity in solids. The chapter presents a review and discusses hydrostatic pressure studies performed on a variety of ionic conductors. The chapter presents discussion on the experimental results and their interpretation in terms of relevant concepts and theory. The chapter presents examples, which illustrate special features or show systematic trends or both. Much of the available pressure work has been on relatively simple materials and crystal structures because these are amenable to theoretical treatment. Some of the materials investigated (for example, PbF2 and the thallous halides) are especially interesting because, among other properties, they possess large dielectric constants and also exhibit relatively soft, low-lying phonon modes. These factors are important in relation to ionic conduction because the larger the dielectric constant of an ionic crystal, the lower the energy of formation of lattice defects. Also, physically, ionic transport occurs by hopping motion across an energy barrier, and this barrier might be expected to become smaller the “softer” the lattice. The chapter presents analysis on the evidence for the connection between these properties and the transport properties. The chapter presents a brief theoretical background with some of the concepts and results necessary for the analysis and interpretation. For this purpose it was found most convenient to divide the substances of interest into several groupings as follows: alkali halides (both NaCl and CsCl types), silver halides, thallium halides, fluorites and related structures, and fast ion conductors.
01 Nov 1984
TL;DR: In this article, surface interactions are considered as being responsible for the effect of ionic dispersions in ionic conductors and the maximum effect to be expected by surface induced defects and optimization conditions are discussed.
Abstract: The finding that dispersions of insulators such as alumina or silica in ionic conductors may exhibit considerably enhanced ionic conductivities compared to the pure material, has become a promising topic for optimizing the electric properties in solid state research. Up to now the basic mechanism for this effect is unknown, the more so since two phase mixtures of two ionic conductors have been found to show a similar enhancement. In this work space charge regions are considered as being responsible for the effect. In the case of insulators as second phases possible surface interactions are taken into account resulting in drawing mobile ions out of the boundary layers and thus increasing the vacancy concentration or in pushing mobile ions into interstitial positions. In the case of two ionic conductors with the same mobile ion, the contact equilibria demand a double effect. The concentration distributions are discussed and lead to a quantitative expression for the space charge contribution in such dispersions. These calculations are in excellent accord with conductivity data of silver chloride (+ alumina, silica) as regards temperature, concentration and particle size. Experiments from the literature are also brought into the discussion. The influence of the surface activities of alumina is tested by modifying the surface chemically. Thermodynamic data for the surface interaction are given. The maximum effect to be expected by conductivity enhancements via surface induced defects and optimization conditions are discussed.
TL;DR: BaSnF 4 has an ionic conductivity of 10 -2 (ω cm) -1 at 500 K and an activation energy of 0.34 eV below 400 K and 0.31 eV above 400 K.
TL;DR: Conductivite ionique de reseaux poly(oxyethylene)-polyurethanne contenant soit du tetraphenylborate de sodium and du perchlorate de lithium in fonction de la concentration en sel a temperature reduite constante T-Tg as mentioned in this paper.
Abstract: Conductivite ionique de reseaux poly(oxyethylene)-polyurethanne contenant soit du tetraphenylborate de sodium soit du perchlorate de lithium en fonction de la concentration en sel a temperature reduite constante T-Tg