Lithium-sulfur battery containing an additive in the electrolyte

Lithium-Sulfur Battery Forming a LiF/LiCl Composite SEI via Fluorine-Chlorine Substituted Dioxolane Additives

This technology incorporates a fluorine and chlorine-substituted 1,3-dioxolane additive into the lithium-sulfur battery electrolyte. During charging, this forms a composite SEI layer containing both LiF and LiCl on the lithium metal anode surface, effectively suppressing lithium dendrite growth.

In lithium-sulfur batteries, lithium metal anodes are prone to dendrite growth during repeated charge-discharge cycles, posing risks of short circuits and fires. Additionally, rapid electrolyte consumption has historically limited battery lifespan.

This technology adds 0.5–10 wt% of 4,4,5,5-tetrachloro-2,2-difluoro-1,3-dioxolane to the electrolyte to create an SEI layer at the anode interface that combines LiCl for fast ion diffusion and LiF for high mechanical strength. The resulting poly(dioxolane) polymer provides flexibility to absorb anode volume changes. Applicable to lithium-sulfur batteries and various lithium-metal batteries using ether-based electrolytes, this single additive enables the in-situ formation of a protective film that balances strength and ion conductivity.

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Key Features:

• A lithium metal anode that faces a cathode containing sulfur-based materials and serves as the anode for a lithium-sulfur battery
• An electrolyte positioned between the cathode and anode, containing a dioxolane-based compound where R1 through R6 are halogen elements
• An additive consisting of 4,4,5,5-tetrachloro-2,2-difluoro-1,3-dioxolane, included at 0.5 to 10 wt% of the total electrolyte
• An SEI layer formed on the anode at the interface between the anode and the electrolyte, containing CFx, LiF, and LiCl

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This invention was developed with support from the Ministry of Science and ICT for the development of core technologies for high-energy-density lithium metal batteries based on the design of natural organic/inorganic composite membrane formation reactions.

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