Interfacial Defect of Lithium Metal in Solid-State Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Computational Modeling

Background:

• All-solid-state batteries utilizing lithium metal anodes offer high energy density and enhanced safety.
• Interfacial failure between lithium metal and solid electrolytes (SE) currently limits their practical application.
• Understanding defects at Li-SE interfaces is crucial for improving lithium metal anode performance.

Purpose of the Study:

• To investigate the atomic-scale defects at Li-SE interfaces.
• To understand the impact of these defects on lithium cycling and interfacial stability.
• To identify strategies for mitigating interfacial failure in lithium metal anodes.

Main Methods:

• Large-scale atomistic modeling of Li metal interfaces with common solid electrolytes.
• Systematic comparison of incoherent, coherent, and semi-coherent Li-SE interfaces.
• Analysis of defect formation and its effect on Li stripping and plating.

Main Results:

• A nanometer-thin layer of disordered lithium forms at Li-SE interfaces.
• This interfacial defect layer promotes failure mechanisms like pore formation and contact loss during Li stripping.
• Interfaces with high lattice coherence exhibit fewer lithium defects and suppressed interfacial failure.

Conclusions:

• Atomistic lithium defects at interfaces play a critical role in the failure of Li metal anodes.
• Optimizing interfacial lattice coherence is a promising strategy to enhance the stability of Li metal anodes.
• This work provides fundamental insights for atomistic-level interfacial engineering in solid-state batteries.