Improvement of interfacial stability between Na metal and Na3PS4 family solid electrolyte for all-solid-state sodium metal batteries

Abstract

In the realm of solid-state batteries, sodium-based batteries are gaining prominence as viable alternatives to traditional lithium-based systems, driven by the increasing need for sustainable energy storage solutions. Despite this progress, challenges persist in addressing interfacial side reactions between sodium and solid-state sodium electrolytes (SSEs). This study addresses challenges associated with sodium-based all-solid-state metal batteries (ASSMBs) by introducing a novel approach utilizing a 4µm-thick NaTFSI/PVDF-HFP (4:10) membrane (MEM) as an artificial interface layer (AIL) between sodium and SSEs. The membrane, exhibiting exceptional properties due to highly polarizable fluorinated groups and a high dielectric constant, facilitates effective interfacial contact between sodium and SSEs while preventing their decomposition. This innovative strategy enhances the interfacial stability of sodium and SSEs, leading to improved performance in both symmetric cells (Na/MEM | SSE | MEM/Na) and full cells (Na/MEM | SSE | TiS2), contributing significantly to the advancement of safer and more efficient energy storage solutions. The developed NaTFSI/PVDF-HFP membrane emerges as a promising solution for enhancing the interfacial stability of sodium-based ASSMBs, thereby paving the way for the development of safer and more efficient energy storage systems.