Effect of anion substitution on the structural and transport properties of argyrodites CuPSeS.

Inspired by the good performance of argyrodites as ion conducting thermoelectrics and as solid electrolytes we investigated the effect of isovalent S substitution for Se in CuPSe. At room temperature CuPSe crystallizes in the primitive cubic β-polymorph of the argyrodite structure and transforms to the face-centered high-temperature (HT) γ-modification above 320 K. The transition for the homologous CuPS occurs at 510 K.