Rapid crystallization of Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) ₃ glass ceramics via ultra‐fast high‐temperature sintering (UHS)

Abstract Lithium aluminum germanium phosphate solid electrolyte is a promising candidate for all‐solid‐state batteries. The currently available processing techniques based on melting‐quenching require a rather lengthy crystallization step lasting up to 8 hours. In this work, the newly emerged ultra‐fast high‐temperature sintering (UHS) was proposed to achieve in a single step reactive consolidation of powder mixture (GeO ₂ , Al(PO ₃ ) ₃ , LiPO ₃ ) and crystallization of the electrolyte within 16 minutes. Samples produced using UHS had a better phase purity, reduced Li loss, and improved ionic conductivity when compared to the counterparts prepared using conventional crystallization at 850°C for 6 h. In fact, specimens prepared by UHS achieved a crystallinity of 90% and ionic conductivity as high as 1.31 × 10 ⁻⁴ S cm ⁻¹ .