Self-Templated 3D Porous Sulfide Solid Electrolytes for Solid-State Sodium Metal Batteries

Rechargeable solid-state sodium (Na) batteries have gained great attention for their high-safety, high energy density and low cost. However, due to the high reactive Na anode, poor electrolyte/electrode interfaces compatibility is the biggest obstacle for inorganic sulfide solid electrolytes (e.g., Na₃MS₄, M=P, Sb) to achieve high performance batteries. Thus, it is necessary to design the nanostructure of sulfide solid electrolyte (SE) and modify interface to address that challenge on the electrochemical instability. In this talk, we will introduce a facile and simple synthesis to prepare Na₃SbS₄ (NSS) sulfide solid electrolyte with 3D porous framework, which can be further infiltrated with a phase transition polymer to form a composite solid electrolyte. The Na₃SbS₄-based composite (NSSC) exhibits enhanced interface stability towards Na metal compared with pristine NSS. The fabricated cells with structure of Na|NSSC|TiS₂ shows excellent cycling stability for 200 cycles wit decent capacity retention. This result demonstrates great promise of achieving high-energy sodium metal batteries with sulfide solid electrolytes.