Stabilizing Halide Electrolytes against Lithium Metal with a Self-Limiting Layer for All-Solid-State Lithium Metal...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Halide solid-state electrolytes (SSEs) offer high ionic conductivity and voltage stability for all-solid-state batteries.
• Chemical instability at the halide SSE/lithium metal anode interface limits their use in high-energy-density all-solid-state Li metal batteries (ASSLMBs).

Purpose of the Study:

• To develop a protective interface layer for halide SSEs to ensure chemical stability with Li metal anodes.
• To enhance the performance and cycle life of ASSLMBs by mitigating detrimental side reactions.

Main Methods:

• Fabrication of a self-limiting layer (SLL) using InF3 and Li2ZrCl6 (LZC).
• In situ formation of a LiF-rich passivation layer at the LZC/Li metal anode interface.
• Electrochemical testing of Li metal symmetric cells and ASSLMBs.
• Density functional theory (DFT) calculations and post-cycling characterization.

Main Results:

• The SLL effectively suppresses side reactions between the halide SSE and Li metal anode.
• Li metal symmetric cells demonstrated over 3000 hours of stable cycling.
• ASSLMBs with the SLL achieved 99.2% capacity retention over 100 cycles at 0.5 C and 83.5% at 2 C after 250 cycles.
• DFT and experimental data confirmed the formation of a protective LiF-rich layer.

Conclusions:

• The developed SLL provides effective kinetic passivation for the halide SSE/Li metal anode interface.
• This strategy enables the use of stable halide SSEs in high-performance ASSLMBs.
• The self-limiting interface protection is a viable approach for advancing ASSLMB technology.