Crystallization and glass transition kinetics of Na₂s-P₂s₅-based super-ionic glasses

In the present study, sulfide glass xNa2S-(100-x)P2S5, 35 ≤ x ≤ 55 has been synthesized by the melt quenched technique. All the glass samples are characterized by x-ray diffraction (XRD), differential thermal analysis (DTA), dilatometery, and impedance spectroscopy. The XRD pattern of a sample showing a broad halo indicates its amorphous nature. Dilatometric study demonstrates that for x = 45 and x = 55 mol% Na2S samples exhibited higher thermal stability than x = 35, x = 40, and x = 50 samples. To understand the crystallization kinetics, DTA was carried out for x = 45 and 55 samples at different heating rates, viz. 10, 20, 30, and 40°C/min. Crystallization kinetics of synthesized glasses for x = 45 and 55 are calculated using Kissinger's model. The thermal expansion coefficient (TEC) of glasses for x = 45 and x = 55 is found to be almost comparable to β-alumina solid electrolyte, which is being used in rechargeable batteries.