Crystallization Process for Superionic Li ₇ P ₃ S ₁₁ Glass–Ceramic Electrolytes

The crystallization process of the 70Li 2 S·30P 2 S 5 (mol%) glass was investigated to obtain a guideline for enhancing the crystallinity of Li 7 P 3 S 11 crystals in a glass–ceramic. Results show that the glass softened at around 240°C and that surface crystallization of the glass started at around 250°C. The heat‐treatment conditions with a maximum nucleation rate for the glass were estimated using DSC measurements. The glass–ceramic prepared using two‐step heat treatment of 210°C for 30 min (nucleation) and 280°C for 1 h (crystallization) exhibited high conductivity of 5.2 × 10 −3 S/cm at room temperature.