Studies of diffusion phenomena in 2D superionic conductors of CuCrS₂–AgCrS₂

Abstract

This work presents the results of studies of diffusion phenomena in the compounds of CuCrS₂, AgCrS₂, and their alloys. Chaotic diffusion coefficients are determined on the basis of measurements of partial ion conductivity using the Nernst–Einstein relationship for the Cu_xAg_1–xCrS₂ alloys. For all compositions, the method of radioactive isotopes was used to find self-diffusion coefficients of silver. Studies of silver self-diffusion for the compound of AgCrS₂ were carried out in the temperature range of 473–693 K. The values of diffusion activation energy and the correlation factor are determined. It is shown that the experimentally determined value of the correlation factor agrees well with the theoretically calculated value. The values of chemical diffusion coefficients are determined in the temperature range of 473 to 723 K for all the studied compositions. It is shown that the values of chemical diffusion coefficients that are high as compared to the chaotic diffusion coefficients are due to the high values of thermodynamic factors.