Filament-Induced Failure in Lithium-Reservoir-Free Solid-State Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Solid-state batteries offer safety advantages but can fail due to electrical shorting.
• Fracture and lithium metal filament formation are key failure mechanisms in lithium-reservoir-free solid-state batteries.
• Mechanical stress at the solid electrolyte surface, from electrochemical and mechanical sources, induces fractures and promotes lithium filament growth.

Purpose of the Study:

• To investigate how applied stack pressure influences failure mechanisms in lithium-reservoir-free solid-state batteries.
• To understand the interplay between surface roughness, stack pressure, and stress development.
• To identify the critical factors leading to premature short-circuiting.

Main Methods:

• Electrochemical experiments
• 3D synchrotron imaging
• Mesoscale modeling

Main Results:

• Low stack pressure leads to irregular lithium plating and high local current density, driving failure.
• Higher stack pressure promotes uniform lithium plating but induces high tensile stress at surface notches.
• Notch-like features on the solid electrolyte surface fracture under high tensile stress, causing premature short-circuiting.

Conclusions:

• Stack pressure significantly impacts failure modes in solid-state batteries.
• Optimizing surface morphology and controlling stack pressure are crucial for enhancing battery reliability.
• Understanding stress concentration at surface features is key to preventing short-circuit failures.