Concentrated LiODFB Electrolyte for Lithium Metal Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium metal batteries offer high energy density but suffer from dendrite growth, hindering commercialization.
• Dendrite formation leads to short circuits and safety concerns in lithium metal anodes.

Purpose of the Study:

• To investigate the efficacy of a concentrated lithium difluoro(oxalate)borate (LiODFB) electrolyte in 1, 2-dimethoxyethane (DME) for stabilizing lithium metal anodes.
• To evaluate the electrochemical performance and dendrite suppression capabilities of the LiODFB-DME electrolyte.

Main Methods:

• Utilized a concentrated LiODFB salt in DME as the electrolyte for lithium metal cells.
• Performed galvanostatic cycling tests on Li/Li symmetric cells and Li/LiFePO4 cells.
• Assessed Coulombic efficiency, cycling stability, and performance at elevated temperatures (65°C).

Main Results:

• Achieved high Coulombic efficiency (up to 98.1%) and stable cycling of Li metal anodes without dendrite formation.
• Demonstrated long-term stability of Li/Li cells, cycling for over 3,000 hours at 1 mA cm⁻².
• Observed superior electrochemical performance in Li/LiFePO4 cells using 4 M LiODFB-DME, particularly at high temperatures, compared to conventional electrolytes.

Conclusions:

• The concentrated LiODFB-DME electrolyte effectively suppresses lithium dendrite growth and enhances cycling stability.
• Increased Li+ availability and the properties of LiODFB salt contribute to the observed superior performance.
• This electrolyte system shows significant promise for enabling practical applications of lithium metal anodes in rechargeable batteries.