Stable Solvent-Derived Inorganic-Rich Solid Electrolyte Interphase (SEI) for High-Voltage Lithium-Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• The solid electrolyte interphase (SEI) is crucial for lithium metal anode stability.
• Inorganic-rich SEIs offer good compatibility with lithium metal anodes.

Purpose of the Study:

• To construct a stable, inorganic-rich SEI using a novel electrolyte formulation.
• To enhance the safety and performance of lithium metal batteries.

Main Methods:

• Utilized a hydrofluoroether-diluted, low-concentration electrolyte (0.5 M LiPF6).
• Investigated the effect of hydrofluoroether on solvent decomposition pathways.
• Analyzed the composition and properties of the resulting SEI.

Main Results:

• Successfully constructed a stable, inorganic-rich SEI with abundant Li2O crystals.
• The Li2O-rich SEI demonstrated improved passivation and ion conductivity.
• Achieved 96.1% capacity retention in Li|NCM523 batteries after 200 cycles.
• Demonstrated a 374 Wh kg-1 energy density in a 1.1 Ah Li|NCA pouch cell with 45 stable cycles.

Conclusions:

• Tuning solvent decomposition is an effective strategy for creating stable inorganic-rich SEIs.
• The developed SEI offers a promising approach for practical, high-energy lithium metal batteries.