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A simple route is presented for scalable production of sodium antimony chalcogenides (Na₃SbCh₄; NaSbCh₂with Ch = S, Se) based on the reactions of Na chalcogenides with appropriately selected metal halides in ethanolic solution at room temperature. 

Two novel approaches for liquid-phase synthesis methods for quaternary chalcogenide solid-state electrolytes with the formula Na₁₁Sn₂SbCh₁₂(Ch = S, Se). 

Li 2 S is the key precursor for synthesizing thio-LISICON electrolytes employed in solid state batteries. However, conventional synthesis techniques such as carbothermal reduction of Li 2 SO 4 aren't suitable for the generation of low-cost, high-purity Li 2 S. Metathesis, in which LiCl is reacted with Na 2 S in ethanol, is a scalable synthesis method conducted at ambient conditions. The NaCl byproduct is separated from the resulting Li 2 S solution, and the solvent is removed by evaporation and thermal annealing. However, the annealing process reveals the presence of oxygenated impurities in metathesis Li 2 S that are not usually observed when recovering Li 2 S from ethanol. In this work we investigate the underlying mechanism of impurity formation, finding that they likely derive from the decomposition of alkoxide species that originate from the alcoholysis of the Na 2 S reagent. With this mechanism in mind, several strategies to improve Li 2 S purity are explored. In particular, drying the metathesis Li 2 S under H 2 S at low temperature was most effective, resulting in high-purity Li 2 S while retaining a beneficial nanocrystal morphology (∼10 nm). Argyrodite electrolytes synthesized from this material exhibited essentially identical phase purity, ionic conductivity (3.1 mS cm −1 ), activation energy (0.19 eV), and electronic conductivity (6.4 × 10 −6 mS cm −1 ) as that synthesized from commercially available battery-grade Li 2 S.