Transport properties of solid electrolytes based on MeSm2S4

Abstract

The solid-solution regions in the Me Sm 2 S 4 -Me S and Me Sm 2 S 4 -Sm 2 S 3 ( Me = Ca, Ba) systems are revealed. The average ion, cation, and anion transport numbers of the synthesized solid electrolytes x Sm 2 S 3 [Ca(Ba)S] · (100 -x )Ca(Ba)Sm 2 S 4 ( x = 1-10 mol %) are determined by the electromotive force (emf) method with the use of concentration cells with and without transfer. In the phases under investigation, the ion transfer in the temperature range 673-723 K is provided by sulfide ions ( = 1.00 ± 0.02). The diffusion coefficients of S 2-ions in the solid electrolytes are determined by potentiostatic chronoamperometry. A vacancy mechanism of defect formation is proposed. It is demonstrated that the transport characteristics of the solid electrolytes based on the CaSm 2 S 4 compound are worse than those of the solid electrolytes based on the BaSm 2 S 4 compound.

Electrochemical Methods for Studying Transport Properties and the Type of Ionic Conduction in Solid Electrolytes Based on CaPr2S4 and Ca(Ba)Sm2S4

“…The ternary sulfides and the solid solutions on their basis were obtained using the procedure described in [6,7].…”

“…Investigation of electrochemical properties of systems CaPr 2 S 4 and CaSm 2 S 4 with a discussion of the feasibility of the existence of sulfide-ion transport in them was performed for the first time in [6,7]. The application of methods of x-ray diffraction analysis (XRDA) and classic conductimetry made it possible to establish the existence in these systems of ternary compounds Ca ( Ba ) Sm ( Pr ) 2 S 4 and a double-sided region of solid solutions Ca ( Ba ) S and Sm ( Pr ) 2 S 3 based on them.…”

Utilizing Sulfide-Selective Membranes with Regenerated Properties in Sensors of Sulfur-Containing Gases

“…Every subsequent measurement was conducted with an identical rate of supply of argon after attaining a constant initial value of emf or a certain time period after taking a measurement, if the blowing with the inert gas was absent. The measurements were conducted in the temperature interval 673-873 K, within limits of which the electrolytes that were utilized in this work possess practically unipolar sulfide-ion conduction (transport numbers for sulfur = 0.9 ± 0.1) [7][8][9].…”

“…(1) The scheme of the construction of the sensor includes three major elements as follows: C | Me + MeS, which are references electrodes, which are manufactured out of sulfides of metals with an additive of relevant metals, which are required in order to stabilize the composition of the sulfides and to obtain a fixed partial pressure of sulfur, which would correspond to the boundary of homogeneity of MeS on the side of excess Me; SEM( S 2-), which is an ion-selective solid electrolyte membrane, which is made of solid solutions of binary sulfides of alkaline-earth and rare-earth metals on the basis of ternary chemical compounds, i.e. thiolanthanates, which possess predominant conduction by the sulfide ion, with the average-ion transport numbers amounting to 10 -4 to 10 -6 [7][8][9]; and the final element is the detector (or working) electrode, which is a mixture of the sulfur-containing gas to be detected and argon at the graphite/solid electrolyte interface.…”