Compatible Dynamically Wetting Electrolyte-Electrode Interface Design for Solid-State Lithium-Sulfur Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state lithium-sulfur batteries offer high energy density but face challenges with ion transport at interfaces and lithium dendrite formation.
• Existing solid polymer electrolytes often struggle with achieving stable and efficient electrode/electrolyte interfaces.

Purpose of the Study:

• To develop a novel solid polymer electrolyte (SPSLL) with a dynamic wetting mechanism for improved solid-state lithium-sulfur batteries.
• To address limitations in ion transport and interfacial stability in solid-state batteries.

Main Methods:

• Fabrication of a solid polymer electrolyte (SPSLL) using a sulfonated copolymer skeleton, incorporating PVDF-HFP, succinonitrile, LiTFSI, and a liquid metal (LM) phase.
• Implementation of a dynamic wetting mechanism to enhance electrolyte-electrolyte and electrolyte-electrode interfaces.
• Testing of the SPSLL in a Li||SPAN solid-state battery to evaluate cycling stability, capacity retention, and Coulombic efficiency.

Main Results:

• The SPSLL demonstrated enhanced lithium salt dissociation and improved thermal stability due to its sulfonated polymer skeleton.
• The liquid metal phase facilitated dynamic active sites, strengthening interfacial contact and promoting alloyed solid electrolyte interphases.
• The Li||SPAN battery with SPSLL achieved 92.2% capacity retention and 99.9% Coulombic efficiency after 500 cycles, with an initial specific capacity of 948 mAh g⁻¹.

Conclusions:

• The dynamic wetting strategy using SPSLL effectively resolves interfacial issues in solid-state batteries.
• This approach significantly enhances the cycling stability and performance of solid-state lithium-sulfur batteries.
• The study presents a promising direction for designing advanced interfaces in next-generation solid-state batteries.