Preparation of sodium ion conducting Na3PS4–NaI glasses by a mechanochemical technique

•Na3PS4–NaI glass electrolytes were prepared by a mechanochemical technique.•Conductivities of the glasses increased with increasing the NaI content.•The glass with 29 mol% NaI showed the highest conductivity of 1.4 × 10− 5 S cm− 1.•Na3PS4–NaI glass-ceramics were prepared by heat treatment of the glasses.•Conductivities of the glass-ceramics were over 10− 4 S cm− 1 at 25 °C.

Structures and ionic conductivities of the (100 − x)Na3PS4∙ xNaI (0 ≤ x (mol%) ≤ 33) glasses and glass-ceramics were investigated. In the XRD patterns, halo patterns were observed in the composition range of 0 ≤ x ≤ 29. The glass-ceramics were prepared by a heat treatment of the glasses. In the glass-ceramics with NaI, an unknown phase which has not been reported was mainly precipitated. The Raman spectra of the glasses and glass-ceramics indicated that all samples included the PS43− units. The conductivities of glasses increased with increasing the NaI content, and the 71Na3PS4 ∙ 29NaI glass showed the highest conductivity of 1.4 × 10− 5 S cm− 1. The conductivities of the glass-ceramics at all composition were over 10− 4 S cm− 1.