Operando Investigation of Solid Electrolyte Interphase Formation, Dynamic Evolution, and Degradation During Lithium...

Area of Science:

• Electrochemistry
• Materials Science
• Battery Technology

Background:

• The solid electrolyte interphase (SEI) is crucial for lithium metal battery stability and performance.
• Characterizing the SEI is challenging due to its thin, dynamic, and sensitive nature.

Purpose of the Study:

• To directly probe the electronic conductivity of the SEI during its formation and degradation.
• To understand the relationship between SEI properties and lithium plating-stripping behavior.

Main Methods:

• Scanning electrochemical microscopy (SECM) for surface electronic conductivity.
• Operando electrochemical quartz crystal microbalance (EQCM) for mass changes.
• Ex situ X-ray photoelectron spectroscopy (XPS) for compositional analysis.

Main Results:

• Stable anode passivation was observed at 0.5 V vs Li/Li+, independent of anion decomposition potentials above 1.0 V.
• Lithium plating-stripping was found to rupture the SEI.
• Current efficiency during plating-stripping correlates with SEI anodic stability.

Conclusions:

• The SEI's electronic conductivity and stability are critical for battery performance.
• SEI rupture by lithium plating-stripping highlights an interdependent relationship.
• Insights gained can guide the design of robust SEI layers for advanced lithium metal batteries.