Solid Electrolyte Interphase Evolution on Lithium Metal in Contact with Glyme-Based Electrolytes.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• A stable solid electrolyte interphase (SEI) is essential for the functionality and longevity of lithium metal batteries.
• Glyme-based electrolytes are commonly used but require careful SEI management for optimal performance.

Purpose of the Study:

• To investigate the formation and evolution of the SEI in glyme-based electrolytes under various conditions.
• To compare the impact of different SEI components, specifically Li_xS_y and Li₃N, on battery stability.
• To comprehensively track the chemical and electrochemical changes of the SEI during battery cycling.

Main Methods:

• Open circuit voltage holds and constant current cycling of lithium metal cells with glyme-based electrolytes.
• X-ray photoelectron spectroscopy (XPS) for chemical analysis of the SEI.
• Electrochemical impedance spectroscopy (EIS) for evaluating the electrochemical properties of the SEI.

Main Results:

• The study identified Li_xS_y species as detrimental components within the SEI.
• Li₃N was found to be a more beneficial component for SEI stability compared to Li_xS_y.
• Detailed chemical and electrochemical evolution of the SEI was mapped under galvanostatic conditions.

Conclusions:

• The composition of the SEI significantly impacts lithium metal battery performance.
• Minimizing Li_xS_y formation and promoting Li₃N are key strategies for enhancing SEI stability.
• Understanding SEI evolution is critical for designing next-generation high-performance lithium metal batteries.