Ionic Conductivity Of Solid Electrolytes Research Articles

Glass dispersion favours ionic conduction in 6Li2SO4-4Li2CO3 composite solid electrolyte

The effect of a dispersion of 7Li2O-3B2O3 glass on the electrical conductivity of 6Li2SO4-4Li2CO3 eutectic has been studied. The samples were prepared by two different methods. With the dispersion of glass into the crystalline matrix a prominent increase in the conductivity has been observed. The results have been explained in the light of dispersed phase theory using microstructural evidence. These results would provide a new approach for achieving an enhancement in the ionic conductivity of solid electrolytes.

Ionic Conductivity of Solid Electrolytes Based on Lithium Titanium Phosphate

Solid electrolytes based on lithium titanium phosphate were prepared, and their phase, porosity of the sintered pellets, and electrical conductivity were studied. The conductivity was increased and the porosity decreased greatly by partially replacing Ti4+ and P5+ in with M3+ and Si4+ions, respectively. The maximum conductivity at 298 K is for . The conductivity was considerably increased by the mixing of binders such as or with . The main reason for the conductivity enhancement of these electrolytes seems to be attributable to the increase of the sintered pellet density with the enhancement of the lithium concentration at the grain boundaries.

ChemInform Abstract: Solid Ion Conductors in Heterogeneous Catalysis

The electrochemical measurement of oxygen activity using ion-conducting solid electrolytes (λ-sensors) has become widely known, at least since the application of three-way catalysts in the postcombustion of exhaust gases from spark-ignition engines. However, the use of solid ion conductors is not limited to control devices. There are various other potential applications and numerous problems which can be studied: the formation of oxides in the course of catalytic reactions on metal surfaces, the improvement of selectivity and yield of catalytic reactions, such as the epoxidation of ethylene on silver catalysts and, finally, the cogeneration of electrical energy during oxidation reactions, such as the partial oxidation of methanol to formaldehyde.

Highly Ion-selective and Super Ion-conductive Solid Electrolyte Thin Films of AgCl Supported in a Porous Glass

Abstract A solid electrolyte thin film of AgCl was prepared in a porous silica plate by supplying silver nitrate and sodium chloride aqueous solutions to the opposite faces of the porous plate. The film showed an extremely selective conductivity of silver ion, greater than that in AgCl crystal by seven orders of magnitude.

Sodium ion-conducting solid electrolytes in the system Na 3PO 4Na 2SO 4

In the system Na 3PO 4Na 2SO 4, the high-temperature, cubic γ form of Na 3PO 4 forms an extensive range of solid solutions: Na 3− x (P 1− x S x )O 4, 0 < x < (0.57 to 0.70, depending on temperature). For compositions in the range x = ca. 0.33 to 0.57, these γ solid solutions are thermodynamically stable at all temperatures. The conductivity of the γ solid solutions increases with increasing x and reaches a maximum at x = 0.5 to 0.6, with values of 2 × 10 −5 ohm −1 cm −1 at 100°C, rising to 1.3 × 10 −2 ohm −1 cm −1 by 300°C; this conductivity increase with x is attributed to an increase in the sodium ion vacancy concentration, associated with the solid solution mechanism Na + PS. The phase diagram for the system Na 3PO 4Na 2SO 4 is given together with lattice parameters of the γ solid solutions.

Structural design of polymeric solid electrolytes to increase ionic conductivity

In order to increase ionic conductivity of solid electrolytes, structural design of some kinds of solvent-free polymer-alkali metal salt (M +K −) complexes was investigated. As the host polymer matrixes, oligo(ethylene oxide) graft copolymer (HPEO) and polyphosphazene (PP) derivatives were chosen, because the flexibility of poly(ethylene oxide) side chains would promote the higher ionic conductivity. Among complexes prepared, PP derivative-LiClo 4 complex showed highest conductivity, 3.5×10 −4 [S/cm] around room temperature. Also a single-ionic conducting only M + is mobile) polymer was realized as the result of copolymerization of p-styrenesulfonyl Li and HPEO. Its dc conductivity decayed only 10 % after applying dc 1 [V] for 24 hours, while the conductivity was relatively low.

Stability of alkali ion-conducting solid and liquid electrolytes; Thermodynamic aspects

Thermodynamic stability windows and decomposition reactions of a variety of low temperature ternary alkali electrolytes are discussed with integration of thermodynamic information, phase equilibria, and the composition dependence of electrode potentials. The question of stability of electrolytes versus alkali metals is considered in general terms. It is shown that low and possibly ambient temperature electrolytes exist - certain alkali organo-aluminum and organo-boron phases - that are truly stable versus alkali metals. Hydroxide electrolytes are found to have large potential stability windows, and some are stable at high alkali activities. Certain low melting halide electrolytes are also stable versus lithium and lithium alloys. Alkali amide salts are otherwise attractive, but have narrow stability ranges.

A Phenomenological Theory for Hysteresis in the Ionic Conductivity of Solid Electrolytes

A phenomenological theory for ionic conductivity and excess heat capacity in solid electrolytes is modified to account for the hysteresis in the ionic conductivity observed in some solid electrolytes. The model is applied to YF3, LuF3, and the (Ag, Cu)2HgI4 eutectic, all of which exhibit large hysteresis loops in their ionic conductivities as they undergo first-order phase transitions. Domain effects are invoked as a means of modulating the width of the hysteresis loop. Eine phanomenologische Theorie fur Ionenleitfahigkeit und Uberschuswarmekapazitaten in festen Elektrolyten wird fur die Beschreibung der Hysterese der Ionenleitfahigkeit, die in einigen festen Elektrolyten beobachtet worden ist, modifiziert. Das Modell wird auf YF3, LuF3, und dem Eutektikum von (Ag, Cu)2HgI4 angewendet, die alle grose Hysterese-Schleifen in ihrer Ionenleitfahigkeiten zeigen, wenn sie durch Phasenubergange erster Ordnung gehen. Domanen-Effekte werden als Methode zur Modulation der Breite der Hysterese-Schleifen benutzt.

Theory of ionic conductivity in solid electrolytes

A quasi-lattice gas model and its simplified particle-continuum model are discussed which give an excellent account of the characteristic features of the dc and the ac ionic conductivity for α-AgI. Classical hopping is also discussed, giving rise to a unified view on the two typical traits of the ac conductivity, Drude type and non-Drude type.

Oxide ion conductors based on bismuthsesquioxide

Oxide ion conductive solid electrolytes based on bismuthsesquioxide are reviewed. These electrolytes are characterized by their conductivities more than ten times higher than those of conventional oxide ion conductors such as stabilized zirconias.

A phenomenological theory for ionic conductivity in solid electrolytes

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Solid Ionic Conductors: Principles and Applications

AbstractSolid ionic conductors, also called solid electrolytes, transport electric current by means of ions. The best known examples of these usually crystalline compounds include doped ZrO2, as well as AgI, β‐Al2O3, and CaF2. Ionic conduction in solid electrolytes reaches its maximum value if a partial lattice of a solid compound undergoes transition at elevated temperature to a quasimolten state. The ionic conductivity in such solid compounds is then as high as in molten salts. Solid electrolytes have found many scientific and technological applications; thus, they can be used to study thermodynamic and kinetic problems, and to build fuel cells, batteries, sensors, and chemotronic components.

Solid-state electrochemistry-New possibilities for research and industry

The mechanism and possible magnitude of the ionic conductivity of solid electrolytes are discussed. Important solid electrolytes are described. Technical and scientific applications are treated. Technical applications are, e.g., the construction of batteries, fuel cells, sensors and chemotronic building units. The scientific applications are thermodynamic and kinetic investigations not only of solids but also of liquids and gases.

Ionic Conductivity in Solid Electrolytes Based on Lithium Aluminosilicate Glass and Glass‐Ceramic

Ionic conductivity measurements on , i.e., , glass and glass‐ceramic have shown these materials to be good lithium ion conducting solid electrolytes at high temperatures. This composition crystallizes in the β‐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 (β‐eucryptite) samples were crystallized (aided by and nucleating agents) by using a heat‐treatment determined through differential thermal analysis. The conductivity (σ) was measured (to 650°C) with a variety of techniques, including 2‐terminal a.c., 3‐terminal guarded a.c., 4‐terminal a.c., 2‐terminal d.c., and a pulsed method. Vapor‐deposited Cr contacts were used. Different sample geometries, contact geometries, and measurement circuitries were employed. The results from the various measurements are in excellent agreement. The a‐c techniques appear to be the most versatile and accurate of the methods examined. In these materials the conductivity is thermally activated with typical values of and for the glasses, and and for the glass‐ceramics. The and nucleating agents [concentrations up to 2.8 mole per cent (m/o)] did not appear to influence the ionic conductivity. Data were also taken on a (β‐eucryptite) glass‐ceramic with a composition near the β‐eucryptite/β‐spodumene phase boundary. The ionic conductivity of this material is lower than that of the materials. Data are also provided on β‐spodumene material.

Cation Diffusion and Conductivity in Solid Electrolytes. I

The characteristics of cation diffusion and ionic conductivity in solid electrolytes are discussed using β- and β″-alumina as examples. The problem is characterized by a cation migration by the vacancy mechanism in a “cation-disordered phase,” a system in which the number of available vacant sites is of the same order of magnitude as the number of diffusing cations. The path probability method is used to derive both the tracer diffusion and the ionic conductivity; this method avoids the difficulties connected with the application of the ordinary random walk approach to such systems. β″-Alumina is regarded as an example of the “cation-disordered phases” in which all available cation sites are equivalent, while β-alumina represents those in which available cation sites are divided into several nonequivalent sublattice sites. When the derived diffusion coefficient is interpreted using the language of the conventional random walk approach, the jump frequency of cations is found to include two factors, the vacancy availability factor V and the effective jump frequency factor W, both of which take into account the effect of surroundings of the migrating ion and characterize the cooperative mode of the cation motion. Both of these factors, as well as the correlation factor f, depend strongly on composition of cations and on temperature. The Nernst–Einstein relation which relates the tracer diffusion and the charge diffusion is found to include characteristic correlation factors. Even in ionic conductivity, a correlation factor fI is found to appear in the β-alumina-type electrolytes. Although both f and fI vary drastically depending on the cation concentration, the ratio of the two remains within limits determined by the geometry of the crystal lattice. The value of the ratio indicates the predominant mechanism of diffusion.

Solid Electrolyte Galvanic Cells

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