Ionic conductivity and diffusion in CuCrS2 - AgCrS2 superionic conductors

The dependence of the ionic conductivity of CuCrS2, and AgCrS2 compounds and their alloys on temperature is measured. Structural studies carried out earlier showed that the CuxAg1-x CrS2 alloys exist as a mixture of CuCrS2 and AgCrS2 phases at temperatures below 673 K and as a solid solution on the basis of a matrix structure at temperatures above 673 K. It is established that for all systems the activation energy for ionic conductivity has a jump at the phase transition point, which corresponds to the temperature of complete disordering of monovalent ionic sublattices. Chemical diffusion coefficients and ionic transport numbers for all tested compounds were determined from the build-up and decay curves of concentration polarization.