Solvent Molecule Cooperation Enhancing Lithium Metal Battery Performance at Both Electrodes

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Rechargeable lithium metal batteries (LMBs) are crucial for next-generation energy storage.
• Developing stable and efficient electrolytes is a major challenge for LMBs.
• Electrolyte decomposition on electrode surfaces impacts battery performance.

Purpose of the Study:

• To investigate the role of solvent components in electrolyte decomposition within LMBs.
• To develop a high-performance electrolyte for Li||LiFePO4 batteries.
• To understand the synergistic effects of different solvent molecules on battery performance.

Main Methods:

• Studied Coulombic efficiencies and cycle lives of LMBs with various electrolyte solvents (ethylene carbonate, dimethyl carbonate, ethylene sulfite).
• Analyzed the influence of solvent components dominating the Li+ solvation sheath on electrode decomposition.
• Developed and tested a novel ethylene carbonate-ethylene sulfite (EC-ES) electrolyte.

Main Results:

• Electrolyte decomposition is dependent on the solvent component in the Li+ solvation sheath.
• The EC-ES electrolyte demonstrated high performance in Li||LiFePO4 batteries.
• Carbonate molecules in the solvation sheath improved Coulombic efficiencies for both anode and cathode.
• Sulfite molecules promoted a desirable solid electrolyte interphase (SEI) and extended Li metal anode cycle life.

Conclusions:

• The composition of the Li+ solvation sheath significantly influences electrolyte stability and battery performance.
• The synergistic interaction between carbonate and sulfite solvents in the EC-ES electrolyte leads to enhanced Coulombic efficiency and cycle life.
• This study provides a new strategy for electrolyte optimization in high-performance LMBs.