Enhancing interface stability and ionic conductivity in the designed Na₃SbP_0.4xS_4-xO_x sulfide solid electrolyte...

The all-solid-state sodium battery has emerged as a promising candidate for energy storage. However, the limited electrochemical stability of the solid electrolyte, particularly in the presence of Na metal at the anode, along with low ionic conductivity, hinders its widespread application. In this work, the design of P and O elements in Na₃SbS₄ solid electrolyte was investigated through a series of structural tests and characterizations. The electrochemical stability was remarkably improved in the Na/Na₃SbP_0.16S_3.6O_0.4/Na battery, exhibiting a stability of 260 h under a current of 0.1 mA cm^-2. Additionally, the room temperature conductivity of Na₃SbP_0.16S_3.6O_0.4 was enhanced to 3.82 mS cm^-1, maintaining a value comparable to commercial standards. The proposed design strategy provides an approach for developing sodium ion solid-state batteries with high energy density and long lifespan. The stability of the solid electrolyte interface at the Na | solid electrolyte interface proves critical for the successful assembly of all-solid-state sodium ion batteries.