Chemo-Mechanical Failure and Reinforcement of Solid Electrolyte Films for Practical All-Solid-State Li Metal Pouch...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state Li metal batteries (ASLMBs) promise high energy density but practical pouch cell integration is limited.
• Integrating thin solid electrolyte films under high assembly pressures poses a significant challenge, often overlooked.
• Conventional sulfide solid electrolytes show incompatibility with Li metal during pouch cell fabrication.

Purpose of the Study:

• To address the incompatibility of sulfide solid electrolytes with Li metal in ASLMB pouch cells.
• To develop a strategy for enhancing mechanical robustness and Li metal compatibility of solid electrolyte films.
• To enable the practical assembly and high performance of ASLMB pouch cells.

Main Methods:

• Introduced a post-engineering strategy modifying Li6PS5Cl and nitrile butadiene rubber binders.
• Applied high isostatic pressing (up to 450 MPa) to test mechanical robustness.
• Utilized experimental analyses and finite element method (FEM) simulations to understand mechanisms.
• Assembled LiNi0.70Co0.15Mn||Li ASLMB pouch cells without interlayers.

Main Results:

• The post-engineering strategy significantly enhanced mechanical robustness and Li metal compatibility.
• Improved interfacial friction was identified as the key enhancement mechanism.
• Successfully assembled ASLMB pouch cells demonstrating stable 400-cycle performance at 60°C and reliable operation at 30°C.
• Demonstrated a proof-of-concept bipolar-stacked ASLMB pouch cell, indicating scalability.

Conclusions:

• The developed strategy overcomes critical challenges in ASLMB pouch cell assembly.
• This work establishes a new benchmark for ASLMBs and provides design principles for practical high-energy solid-state batteries.
• The findings pave the way for advancing practical all-solid-state battery technologies.