Chlorinated-Solvent-Based Electrolyte for Safe and Stable Lithium Battery Chemistry

Area of Science:

• Electrochemistry
• Materials Science
• Battery Technology

Background:

• Lithium battery safety is a major concern, with current electrolytes offering limited fire retardancy.
• Fluorinated and organophosphorus solvents improve flammability but are insufficient for lithiated anodes.

Purpose of the Study:

• To develop a novel all-chlorinated-solvent electrolyte strategy for durable, non-flammable, and fire-proof lithium batteries.
• To address premature battery failure in chlorinated ether electrolytes by improving anode compatibility and preventing current collector corrosion.

Main Methods:

• Designed an all-chlorinated-solvent electrolyte system.
• Investigated premature failure mechanisms in chlorinated ether electrolytes, identifying issues with the solid electrolyte interphase (SEI).
• Engineered SEI regulation using film-forming chlorinated carbonate and promoted anion reduction.
• Tested graphite||LiFePO4 full cells and high-loading Li||LiNi0.8Co0.1Mn0.1O2 cells with the developed electrolytes.

Main Results:

• Demonstrated that SEI regulation via film-forming chlorinated carbonate and promoted anion reduction overcomes anode incompatibility and aluminum current collector corrosion.
• Achieved high capacity retention and enhanced safety in graphite||LiFePO4 cells under various abuse conditions.
• Attained durable cycling in 4.4 V high-loading Li||LiNi0.8Co0.1Mn0.1O2 cells without current collector corrosion.

Conclusions:

• The all-chlorinated-solvent design strategy enables durable, non-flammable, and fire-proof lithium battery electrolytes.
• SEI regulation is crucial for overcoming limitations in chlorinated ether electrolytes.
• This work provides essential design criteria for developing highly safe, fire-retardant lithium battery electrolytes.