Low-Temperature and Fast-Charging Lithium Metal Batteries Enabled by Solvent-Solvent Interaction Mediated Electrolyte

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium metal batteries offer high energy density but struggle with low-temperature performance and fast charging.
• Current electrolytes based on ethylene carbonate (EC) have limitations in extreme conditions.

Purpose of the Study:

• To develop an electrolyte formulation for improved low-temperature performance and fast-charging capabilities in lithium metal batteries.
• To investigate electrolyte solvation chemistry for enhanced lithium-ion transport and stability.

Main Methods:

• A novel electrolyte was designed using fluoroethylene carbonate (FEC) and 1,2-difluorobenzene (2FB) as a diluent.
• Intermolecular interactions within the electrolyte were studied to understand their effect on Li+ desolvation and freezing point.
• Electrochemical performance of LiNi0.8Co0.1Mn0.1O2||Li cells was evaluated at low temperatures and high charge/discharge rates.

Main Results:

• The new electrolyte effectively lowered the electrolyte freezing point and facilitated Li+ desolvation due to 2FB's intermolecular interactions.
• The formulated electrolyte enabled stable cycling of LiNi0.8Co0.1Mn0.1O2||Li cells at -30 °C for over 100 cycles.
• A high capacity of 154 mAh g-1 was achieved at a 5.0C rate, demonstrating excellent fast-charging performance.

Conclusions:

• The electrolyte solvation chemistry strategy effectively enhances the performance of lithium metal batteries under extreme conditions.
• The study provides a model for understanding electrolyte behavior and offers insights for designing advanced electrolytes for demanding applications.