Sulfide solid electrolyte thin film with high ionic conductive from slurry-casting strategy for all-solid-state lithium batteries

Sulfide solid-state electrolyte (SSE) in all-solid-state lithium batteries (ASSLBs) has attracted increasing attention due to its outstanding safety and high energy density. Nevertheless, the two main challenges of sulfidebased electrolyte are how to reduce the thickness of its film and improve its interfacial stability. In this work, Li6PS5Cl is used as a solid electrolyte, cellulose membrane as a self-limiting skeleton, heptane as a dispersant and SEBS as a binder, and a 90 mu m ultrathin sulfide electrolyte film is prepared by using the free-standing slurry casting strategy. The ionic conductivity of sulfide SSE film is 1.09 x 10-3 S cm-1 at room temperature. Furthermore, the ASSLBs with cathode (LiNbO3@LiNi0.6CO0.2Mn0.2O2) and anode materials (lithium-indium alloy) are prepared. The discharge capacity of the button cells assemble with sulfide solid electrolyte film is 161.2 mAh/g after 150 cycles with a capacity retention of 87 % under 0.1 C at 25 degrees C. This study provides ultrahigh ionic conductivity sulfide-based electrolyte film design principle towards promising possible strategies for ASSLBs.

Automated summary

In this study, a 90 μm ultrathin sulfide electrolyte film with high ionic conductivity was prepared using a free-standing slurry casting strategy. The all-solid-state lithium batteries assembled with this sulfide solid electrolyte film exhibited a capacity retention of 87% after 150 cycles. This research provides a design principle for high ionic conductivity sulfide-based electrolyte films and offers promising directions for future research strategies in all-solid-state lithium batteries.