Safe and Stable Lithium Metal Batteries Enabled by an Amide-Based Electrolyte

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Flammable liquid electrolytes in lithium metal batteries pose safety risks and hinder dendrite formation.
• High-energy-density lithium metal batteries require advanced electrolytes for stable performance.

Purpose of the Study:

• To propose and investigate a novel nonflammable amide-based electrolyte for lithium metal batteries.
• To understand the formation mechanism and solvation chemistry of the proposed electrolyte.
• To evaluate the electrochemical performance and safety of the new electrolyte.

Main Methods:

• Molecular dynamics simulations and density functional theory were employed to study solvation and mechanisms.
• Electrochemical testing was performed using LiFePO4 and LiMn2O4 cathodes.
• The electrolyte composition included LiTFSI, butyrolactam, a counter solvent, and additives.

Main Results:

• A nonflammable amide-based electrolyte with high ionic conductivity, thermal stability, and electrochemical stability (>4.7 V) was successfully developed.
• An inorganic/organic-rich solid electrolyte interphase (SEI) composed of LiF, Li3N, and Li-N-C was formed in situ.
• The SEI layer facilitated spherical lithium deposition, suppressing dendrite formation.
• Stable cycling performance was achieved at room temperature and 60°C in lithium metal batteries.

Conclusions:

• The novel amide-based electrolyte offers a promising solution for safe and high-performance lithium metal batteries.
• The in situ formed SEI layer is crucial for enabling stable lithium metal cycling.
• This research provides valuable insights into developing advanced amide-based electrolytes for next-generation energy storage.