Glass Formation and Ionic Conduction Behavior in GeSe₂–Ga₂Se₃–NaI Chalcogenide System

Abstract

Series of glassy and glass‐ceramic samples in the GeSe2–Ga2Se3–NaI system is prepared by melt‐quenching technique and the glass‐forming region is well‐defined by XRD investigations. Na‐ion conduction behavior is systemically studied by impedance measurements. For the glasses in the series (100−2x)GeSe2–xGa2Se3–xNaI, ionic conductivities increased with increasing x, whereas the attributed activation energy of ion conduction decreases. The enhanced mechanism is discussed by employing Raman spectra. In addition, the effect of the crystal phases NaI and Ga2Se3 on the ionic conduction behavior in the (70−x)GeSe2–xGa2Se3–30NaI samples is discussed. Although it shows that the poorly conducting crystallites of NaI and Ga2Se3 have a negative effect on the ionic conductivities in this series, the highest ionic conductivity of 1.65 × 10−6 S/cm is obtained in the 45GeSe2–25Ga2Se3–30NaI glass. Finally, this study also demonstrates a possible way to search appropriate Na‐ion solid electrolytes for all‐solid‐state batteries.

Ultra-stable sodium metal-iodine batteries enabled by an in-situ solid electrolyte interphase

“…This result indicates an improved diffusion dynamics of Na + ions in Na-NaI anode compared with that of pristine Na anode with a formed SEI in carbonate electrolyte [45]. Meanwhile, Sodium iodide (NaI) is an ionic compound with an ionic conductivity of ～3 × 10 −2 S/cm, and it has been reported that the introduction of NaI can enhance the ionic conductivity of sodium solid electrolyte (1.6 × 10 −5 S/cm for 45Ge-Se 2 -25Ga 2 Se 3 -30NaI glass) [46]. In particular, NaI can also be combined with PEO for preparing high ionic conductivity polymer electrolyte (such as PEO-NaI, 5.21 × 10 −5 S/cm) [47,48].…”

Ab initioinvestigation of the stability of electrolyte/electrode interfaces in all-solid-state Na batteries

“…These binaries are generally used as synthesis precursors, e.g., M 2 S or M 2 Se in chalcogenide-based glassy electrolytes, or as additives (especially the halides) to improve the electrochemical performance of more complex electrolyte materials. [67][68][69][70] In all of these binary materials, the anion is fully reduced; therefore, further reaction with the metal anode cannot occur and they are all stable down to 0 V against M/M + .…”

Glass formation and physical properties of Sb2S3–CuI chalcogenide system*

“…The linear dependence of log σ versus (1/T ) follows the Arrhenius law and indicates phase stability over the given temperature range. [20,27] The ionic conductivity of 45Sb 2 S 3 •55CuI glassceramic is more than two order of magnitude higher than that of 70Sb 2 S 3 •30CuI glass. Activation energy (E a ) of Cu + conduction was determined by using the Arrhenius equation and listed in Table 2.…”

“…In addition, fast Cu-ion conduction was also investigated in this glassy system, which is of guiding significance for future designing solid glassy electrolytes. [19][20][21][22]…”