Strategies of Interface Stabilization for Sulfide-Type Sodium Ion Conductors in Solid-State Na Batteries

Due to the abundant sodium (Na) resources in contrast to lithium (Li), the development of sodium-based batteries has become increasingly appealing, making them promising next-generation energy storage solutions for medium- or large-scale systems. Solid-state Na batteries, replacing liquid electrolyte with solid-state ion conductors, provide great potential to improve the energy density, safety and thermal stability. The most popular Na-ion conductors include oxides, sulfides, halides, etc. Each of them shows their unique strength but also is facing their own challenges. Take sulfide-type solid Na-ion conductors as example, they display impressive advantages of high ionic conductivity and densification by cold-pressing, and composition flexibility, and straightforward synthetic approaches, etc. However, they also exhibit air-sensitively and interface instability with Na metal and oxide-based cathode.

In this talk, we will introduce our recent progress to address the interface instability challenge in solid-state Na metal batteries when using representative sulfide-type solid conductors.[1,2] The strategies include: 1) the composition design for solid electrolyte; 2) the materials structure design of solid electrolyte; and 3) the artificial interlayer design at interface. Through these strategies, stable interface between solid electrolyte (Na₃SbS₄-family conductors) and Na metal will be formed, and the solid-state Na batteries with metal sulfide as cathode will be cycled with extended cycling life. These works aim to promote the development of sulfide-based solid ion-conductors for applications in solid-state batteries to achieve high performance.

[1] X. Guo, Y. Li, H. Wang, ACS Appl. Eng. Mater., 2024, 7, 1008-1014.
[2] Y. Li, W. Arnold, S. Halacoglu, J. Jasinski, T. Druffel, H. Wang, Adv. Fun. Mater., 2021, 31, 2101636