Transport properties of solid electrolytes based on MeSm2S4

Abstract

The solid-solution regions in the MeSm2S4-MeS and MeSm2S4-Sm2S3 (Me = Ca, Ba) systems are revealed. The average ion, cation, and anion transport number of the synthesized solid electrolytes xSm2S3[Ca(Ba)S] · (100 − x)Ca(Ba)Sm2S4 (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 (\(t_{S^2 } \) = 1.00±0.02). The diffusion coefficients of S2− 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 CaSm2S4 compound are worse than those of the solid electrolytes based on the BaSm2S4 compound.