Melt Quenching Process for the Synthesis of Na₅MSi₄O₁₂-Type Compounds, Sodium-Ion Conducting Solid Electrolytes

Na₅MSi₄O₁₂-type compounds are emerging as viable solid electrolytes for solid-state sodium batteries because of their high ionic conductivity and excellent stability. However, Na₅MSi₄O₁₂-type compounds are often prepared by traditional solid-state synthesis, which involves extensive ball-milling, long sintering times, and multiple processing steps to produce high-purity materials. This leads to long preparation times and energy inefficiency. Here, we show that glasses of Na₅MSi₄O₁₂ (M = Y, Dy, Gd, and Sm) can be synthesized via a simple melt-quenching process. Subsequent annealing of these glasses at respective temperatures resulted in highly conductive glass ceramics. The structure and properties of these glasses and glass-ceramics were studied using simultaneous thermal analysis, XRD, SEM, FTIR, Raman, and EIS. This article presents an energy-efficient, simple, and alternative approach to the synthesis of promising Na₅MSi₄O₁₂-type solid electrolytes for solid-state sodium-ion batteries.