Preparation of sodium-ion-conductive Na₃₋<i>_x</i>SbS₄₋<i>_x</i>Cl<i>_x</i> solid electrolytes

Abstract

Solid electrolytes have become important materials for improving the performance of next-generation all-solid-state sodium rechargeable batteries. Therefore, sodium vacancy doping for Na3SbS4 electrolytes was performed by partially substituting Cl for S. Na3−xSbS4−xClx electrolytes were prepared using a mechanochemical process and consecutive heat treatment. The structures, ionic conductivities, and air safety of the prepared Na3−xSbS4−xClx electrolytes were evaluated via X-ray diffraction and impedance, air stability, and electrochemical tests. The Na2.9375SbS3.9375Cl0.0625 electrolyte showed a higher room-temperature ionic conductivity of 2.9 × 10−3 S cm−1 than that of the Na3SbS4 electrolyte. An all-solid-state Na15Sn4/Na2.9375SbS3.9375Cl0.0625/TiS2 cell showed a reversible capacity of approximately 100 mA h g−1 at room temperature. Thus, the Na2.9375SbS3.9375Cl0.0625 solid electrolyte has the potential for application as a solid electrolyte in all-solid-state batteries.