The Raw Mixed Conducting Interphase Affords Effective Prelithiation in Working Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Contact prelithiation is crucial for compensating initial capacity loss in lithium-ion batteries.
• Inadequate lithium conversion during prelithiation generates dead lithium, compromising cycling stability.
• Developing efficient prelithiation strategies is key to improving battery longevity.

Purpose of the Study:

• To investigate the use of a mono-solvent dimethyl carbonate (DMC) electrolyte for contact prelithiation.
• To understand the role of the raw electrolyte interphase (REI) formed during DMC-based prelithiation.
• To improve lithium source utilization and cycling stability in rechargeable batteries.

Main Methods:

• Employing a mono-solvent dimethyl carbonate (DMC) electrolyte for contact prelithiation.
• Analyzing the properties of the raw electrolyte interphase (REI) formed on the lithium source and anode.
• Evaluating battery performance metrics including initial Coulombic efficiency and capacity retention.

Main Results:

• A low-organic-content REI was formed, acting as a mixed ion/electron conductor.
• Electron channels were maintained even with complete REI coverage of the lithium source.
• Achieved 92.8% lithium source utilization and a negligible dead lithium yield.
• Demonstrated a high initial Coulombic efficiency of 90.0% and 94.9% capacity retention over 210 cycles.

Conclusions:

• The DMC-based contact prelithiation strategy effectively minimizes dead lithium.
• The mixed ion/electron conductive nature of the REI is critical for successful prelithiation.
• This method significantly enhances the initial Coulombic efficiency and long-term cycling stability of lithium-ion batteries.