Patent Application for Improved Lithium-Ion Battery Technology

Strategic Insights -

Researchers LEE, Eunsung, PAIK, Chi, and SUN, Liyuan have filed a patent application for a method to improve the performance and durability of lithium-ion batteries. The proposed method involves saturating the battery cells with a carbonate-based electrolyte, followed by flushing out the electrolyte with a soft solvents-based electrolyte. This process creates a lithium fluoride-rich passivation layer between the anode and separator, providing electronic insulation and ionic conduction. The inventors claim that their method can expand the operational voltage and temperature ranges of lithium-ion batteries, while also addressing the challenges of long-term calendar life at elevated temperatures.

Key Takeaways:

  • The proposed method involves a two-step process of saturating battery cells with a carbonate-based electrolyte and then flushing out the electrolyte with a soft solvents-based electrolyte.
  • The lithium fluoride-rich passivation layer formed by the method provides electronic insulation and ionic conduction between the anode and separator.
  • The inventors claim that their method can expand the operational voltage ceiling of lithium-ion batteries from 4.3V to a higher range.
  • The method also enables the formation of a thin layer of cathode and anode solid-electrolyte interfaces, which can improve battery performance.
  • The soft solvents-based electrolyte comprises methyldifluoroacetate and methyldifluoro(sulfonyl)acetate, with the option to include a diluent such as 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether.
  • The method may also involve one or more sealing steps post-saturation and post-flushing.
  • The proposed battery cell design includes a cathode, an anode with a pre-formed lithium fluoride-rich passivation layer, and a soft solvents-based electrolyte saturating the cathode and anode.

Statistics:

  • The patent application was filed on December 12, 2023.
  • The patent application was made available online on June 12, 2025.
  • The method proposes to expand the operational voltage ceiling of lithium-ion batteries from 4.3V to a higher range.
  • The lithium fluoride-rich passivation layer formed by the method provides electronic insulation and ionic conduction between the anode and separator.

Sources:

  • LEE, Eunsung; PAIK, Chi; SUN, Liyuan. Post-Formation Electrolyte Refilling. U.S. Patent Application Number 20250192242, filed December 12, 2023 and posted June 12, 2025. Patent URL (for desktop use only): https://ppubs.uspto.gov/pubwebapp/external.html?q=(20250192242)&db=US-PGPUB&type=ids