AC conductivity study of mechanochemically synthesized solid electrolytes of Li 6- a M a / n n PS 5 Cl (M = Ca, Mg, Ba, Zn, Al, Y).

Argyrodite-type solid electrolytes of Li 6 PS 5 Cl doped with multivalent cations (Mg 2+ , Ba 2+ , Zn 2+ , Al 3+ , Y 3+ ) were prepared via a mechanochemical synthesis method. The lattice constant ( a 0 ), interplanar spacing ( d 220 , d 311 , d 222 ), and micro-strain ( ε ) showed that the doping elements were incorporated into the crystal structure of Li 6 PS 5 Cl. The lattice constant and interplanar spacing of the doped samples were smaller than those of Li 6 PS 5 Cl. The prepared samples exhibited a positive lattice strain, and the substituted samples exhibited higher strains than Li 6 PS 5 Cl. The doped samples exhibited higher ionic conductivity than Li 6 PS 5 Cl at 25 °C. Li 5.94 Al 0.02 PS 5 Cl exhibited the highest σ DC of approximately 2.36 × 10 -3 S cm -1 at 25 °C. The charge carrier movement at the grain boundary changing from long-range diffusion in Li 6 PS 5 Cl to short-range diffusion in Li 5.94 Al 0.02 PS 5 Cl enhanced the conductivity.