Promoting a Stable Interface Using Localized High-Concentration Carbonate-Based Electrolyte for Li Metal Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Rechargeable lithium metal batteries (LMBs) offer high energy density but face challenges with metallic lithium reactivity and cathode instability.
• Achieving excellent cycling performance in high-voltage LMBs remains a significant hurdle for practical implementation.

Purpose of the Study:

• To develop a novel electrolyte formulation for high-voltage rechargeable lithium metal batteries.
• To address the reactivity of metallic lithium and instability of high-voltage cathodes by creating stable interfaces.

Main Methods:

• Formulation of a carbonated-based electrolyte with LiPF6, cosolvent, diluent, and additives.
• Adjustment of electrolyte solvation structure to minimize free carbonate solvent decomposition.
• Investigation of the electrolyte's impact on solid-electrolyte interphase (SEI) formation and lithium deposition.

Main Results:

• Demonstrated a thin, LiF-rich SEI and uniform lithium deposition.
• Achieved a high Coulombic efficiency of 99.5% in Li|Cu half cells.
• Showcased good cycling stability in Li||NMC811 full cells with ~80% capacity retention over 280 cycles.

Conclusions:

• The developed electrolyte effectively stabilizes interfaces in high-voltage LMBs.
• The formulation supports aggressive cathodes and enables uniform lithium deposition, crucial for battery longevity.
• The study highlights the potential of this electrolyte for practical, high-energy-density rechargeable lithium metal battery applications.