Abstract
? 2022 Elsevier B.V.We present a detailed study of Ag7+x(P1?xGex)S6 (x = 0.1; 0.25; 0.33; 0.5; 0.75) single crystals of novel superionic conductors with argyrodite structure. The single crystals on superionic conductors Ag7+x(P1?xGex)S6 were grown by directional crystallization technique. The crystal structure of Ag7+x(P1?xGex)S6 solid solutions was studied by the Rietveld refinement method. It was found that solid solutions crystallize in three SGs: P213 (x = 0.1), F-43m (x = 0.25; 0.33) and Pna21 (x = 0.5; 0.75). Ag7+x(P1?xGex)S6 solid solutions are characterized by the presence of Ag positions with partial occupancy, which is different from the initial ternary compounds. The frequency and temperature dependences of electrical conductivity were studied by electrochemical impedance spectroscopy method. The structural disordering caused by P+5?Ge+4 heterovalent cationic substitution induces increasing ionic conductivity of the solid solutions by 5 orders of magnitude. The occurrence of favorable conditions for ion transport is explained using simple structural descriptors.
NSTL
Elsevier