Insight into the Enforced Stability of the Solid Electrolyte Interphase on the Graphite Anode by Prelithiation

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid electrolyte interphase (SEI) formation causes lithium loss in lithium-ion batteries (LIBs).
• Prelithiation is a strategy to mitigate lithium loss and improve battery cycle life.
• The SEI composition differs between prelithiation and standard charging processes.

Purpose of the Study:

• To investigate the differences in SEI formation between prelithiation and charging in graphite anodes.
• To understand how SEI composition impacts the performance of lithium-ion batteries.

Main Methods:

• Preparation of a prelithiated graphite anode via thermal contact.
• Electrochemical measurements to assess battery performance.
• Spectral characterizations to analyze SEI composition.

Main Results:

• Prelithiation significantly improved initial coulombic efficiency (ICE) and cyclic stability.
• The SEI formed by prelithiation is rich in lithium fluoride (LiF).
• This LiF-rich SEI is more stable and robust than the organic/inorganic carbonate SEI formed during charging.

Conclusions:

• Prelithiation effectively compensates for lithium loss by forming a stable, LiF-rich SEI.
• The LiF-rich SEI enhances the cyclic stability of graphite anodes in LIBs.
• This study highlights the importance of SEI composition for battery performance.