It was found that the ionic conductivity increased monotonically when CuI was gradually replaced by AgI; with no minimum at intermediate concentrations. The 110Ag tracer diffusion coefficient parallelled the conductivity isotherm with almost the same change, of 4 orders of magnitude, from about 10-12 to 10-8cm2/s. The 64Cu tracer diffusion coefficient increased, by a factor of 20 to 30, when Cu was replaced by Ag. The Cu diffusivity was always lower than the Ag diffusivity. The only exception was a 50:50 CuI-As2Se3 glass; for which the Cu and Ag diffusivities were very similar. The results could be explained in terms of a degenerate mixed-cation effect, with differing trends for Ag and Cu mobile cations.

Degenerated Mixed Cation Effect in CuI-AgI-As2Se3 Glasses: 64Cu and 110Ag Tracer Diffusion Studies. A.Bolotov, E.Bychkov, Y.Gavrilov, Y.Grushko, A.Pradel, M.Ribes, V.Tsegelnik, Y.Vlasov: Solid State Ionics, 1998, 113-115, 697-701