Solution Synthesis of Sb2S3 and Na3SbS4 Solid-State Electrolyte

Abstract

Sodium thioantimonate (Na3SbS4) is an attractive solid-state electrolyte for sodium-ion batteries due to its high ionic conductivity and stability in protic solvents. Herein, we describe solution-based routes for its synthesis. First, we demonstrate the synthesis of the Sb2S3 precursor via thermodynamically favorable metathesis between Na2S and SbCl3. This solution-based approach is further extended to couple the resulting Sb2S3 with Na2S for the synthesis of Na3SbS4. It is shown that ethanol is a superior solvent to water for solution-based synthesis of Na3SbS4 with respect to yield, morphology, and performance. Amorphous Sb2S3 synthesized from low-temperature metathesis produced highly crystalline Na3SbS4 with a room temperature Na+ conductivity of 0.52 mS cm−1 and low activation energy, comparable to leading values reported in the literature.