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US-20260128313-A1 - PROTECTIVE MATERIAL FOR A LITHIUM METAL ANODE: METHOD FOR ITS PREPARATION AND USE

US20260128313A1US 20260128313 A1US20260128313 A1US 20260128313A1US-20260128313-A1

Abstract

A protective material for protecting a lithium metal sheet, in particular a lithium metal anode. The material comprises a metal fluoride such as AlF 3 and a fluoro alkylene carbonate such as fluoro ethylene carbonate (FEC). A method for using the protective material is provided.

Inventors

  • Andrea Paolella
  • Catherine GAGNON
  • Alexis PEREA
  • Abdelbast Guerfi
  • Karim Zaghib

Assignees

  • HYDRO-QUéBEC

Dates

Publication Date
20260507
Application Date
20260105

Claims (20)

  1. 1 . A method of treating a surface of a lithium metal sheet, comprising: (a) providing a lithium metal sheet; (b) preparing a material which comprises a complex formed from a mixture comprising a metal fluoride and a fluoro alkylene carbonate; (c) depositing the material on the surface of the lithium sheet and causing the material to spread on the surface; and (d) drying the material, thereby forming a coat of protective material on the surface.
  2. 2 . The method according to claim 1 , wherein step (c) comprises passivating the surface.
  3. 3 . The method according to claim 1 , wherein step (d) is conducted at ambient temperature.
  4. 4 . The method according to claim 1 , wherein the metal fluoride is selected from the group consisting of AlF 3 and ZnF 2 ; and the fluoro alkylene carbonate is a C 2-15 fluoro alkylene carbonate.
  5. 5 . The method according to claim 4 , wherein the C 2-15 fluoro alkylene carbonate is a straight chain hydrofluorocarbon or a branched chain hydrofluorocarbon.
  6. 6 . The method according to claim 1 , wherein the metal fluoride is selected from the group consisting of AlF 3 and ZnF 2 ; and the fluoro alkylene carbonate is a C 2-6 fluoro alkylene carbonate.
  7. 7 . The method according to claim 1 , wherein the metal fluoride is AlF 3 and the fluoro alkylene carbonate is fluoro ethylene carbonate (FEC).
  8. 8 . A method of treating a surface of a lithium metal sheet, comprising: (a) providing a lithium metal sheet; (b) preparing a material which comprises a complex formed from a mixture comprising AlF 3 and fluoro ethylene carbonate (FEC); (c) depositing the material on the surface of the lithium sheet and causing the material to spread on the surface; and (d) drying the material, thereby forming a coat of protective material on the surface.
  9. 9 . The method according to claim 1 , wherein the lithium metal sheet is for use as anode in a battery; optionally the battery is a lithium-ion battery.
  10. 10 . A lithium metal sheet having a surface treated by the method as defined in claim 1 .
  11. 11 . A battery comprising a lithium metal anode having a surface thereof treated by the method as defined in claim 1 .
  12. 12 . The battery according to claim 11 , wherein the electrolyte is a not flammable electrolyte and/or the electrolyte is a gel polymer electrolyte; optionally the not flammable electrolyte is selected from the group consisting of trimethylphosphate (TMP), triethylphosphate (TEP), tributylphosphate (TBP), triethylphosphite (TEPi), and combinations thereof.
  13. 13 . The battery according to claim 11 , wherein the cathode is a cathode having a nickel- and/or manganese-based material; optionally the cathode is selected from the group consisting of nickel manganese cobalt (NMC) and nickel cobalt aluminum oxide (NCA).
  14. 14 . A kit for use in the treatment of a lithium metal sheet, comprising: (a) a metal fluoride; (b) a fluoro alkylene carbonate; and (c) instructions for use.
  15. 15 . The kit according to claim 14 , wherein the instructions comprise: instructions for preparing a material which is a complex formed from a mixture of the metal fluoride and the fluoro alkylene carbonate; and/or instructions for depositing the material on the surface of the lithium sheet and causing the material to spread on the surface; and/or instructions for drying the material, thereby forming a coat of protective material on the surface.
  16. 16 . The kit according to claim 14 , wherein the metal fluoride is selected from the group consisting of AlF 3 and ZnF 2 ; and the fluoro alkylene carbonate is a C 2-15 fluoro alkylene carbonate.
  17. 17 . The method according to claim 16 , wherein the C 2-15 fluoro alkylene carbonate is a straight chain hydrofluorocarbon or a branched chain hydrofluorocarbon.
  18. 18 . The kit according to claim 14 , wherein the metal fluoride is selected from the group consisting of AlF 3 and ZnF 2 ; and the fluoro alkylene carbonate is a C 2-6 fluoro alkylene carbonate.
  19. 19 . The kit according to claim 14 , wherein the metal fluoride is AlF 3 and the fluoro alkylene carbonate is fluoro ethylene carbonate (FEC).
  20. 20 . The kit according to claim 14 , wherein the lithium metal sheet is for use as anode in a battery; optionally the battery is a lithium-ion battery.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisional of U.S. application Ser. No. 17/430,838, filed Aug. 13, 2021, titled “PROTECTIVE MATERIAL FOR A LITHIUM METAL ANODE: METHOD FOR ITS PREPARATION AND USE,” now U.S. Pat. No. 12,519,110, issued Jan. 6, 2026 which is a U.S. national stage of International Application No. PCT/CA2020/050456, filed Apr. 6, 2020, titled “PROTECTIVE MATERIAL FOR A LITHIUM METAL ANODE: METHOD FOR ITS PREPARATION AND USE,” which claims priority to and the benefit of U.S. Provisional Application No. 62/830,777, filed Apr. 8, 2019, the contents of which are hereby incorporated by reference in their entireties. FIELD OF THE INVENTION The present invention relates generally to the control of the reactivity between metallic lithium and the electrolyte in a battery. More specifically, the invention relates to a protective material and use thereof for treating the surface of a lithium metal anode. The protective material according to the invention comprises a metal fluoride and a fluoro alkylene carbonate. BACKGROUND OF THE INVENTION Lithium metal is used as anode in lithium-ion batteries [1]. However, this use is somewhat limited, for safety reasons. Indeed, formation of lithium dendrite may occur, which causes short circuit in the battery. Efforts to deal with this issue have focused on the nature of the electrolyte [2]. Typically, not flammable electrolytes such as trimethylphosphate (TMP), triethylphosphate (TEP), tributylphosphate (TBP), triethylphosphite (TEPi) are used. However, these electrolytes are generally reactive toward lithium metal; and must be used in combination with carbonate solvents in order to avoid any occurrence of unwanted chemical reactions. Other research efforts aim at finding methods of controlling the reactivity between metallic lithium and electrolytes. Various such methods are reported, which involve the use of AlF3. For example, Wang et al. have used AlF3 as scaffold for chemical reactions with melted lithium metal forming new composites based on lithium aluminium alloys and lithium fluoride (LAFN) [3]. AlF3 is used in rechargeable batteries to protect the surface of high voltage cathodes such as Li1.2Ni0.15Co0.10Mn0.55O2 [4] and LiNi0.8Co0.15Al0.05O2 [5]. Wang et al. have reported an improvement in the cycling stability of the battery when using a LiV3O8 cathode coated with AlF3 [6]. Tron et al. have reported an improvement of aqueous LiFePO4 battery performances following a 1-3% weight AlF3 coating of the cathode [7]. AlF3 is used to protect cathodes such as Li4Ti5O12 cathodes; in particular, Li et al. have reported that gas formation is avoided [8]. Graphite anode was protected by AlF3 when adding a mixture of ammonium fluoride and aluminium nitrate [9]. There is still a need for methods of controlling the reactivity between metallic lithium and the electrolyte in a battery. In particular, there is still a need for methods of protecting the surface of a lithium metal anode in a battery. Moreover, there is a general need for methods of protecting a lithium metal surface toward reactivity with other reagents. SUMMARY OF THE INVENTION The inventors have designed and prepared a material for protecting the surface of a lithium metal sheet. In particular, the inventors have designed and performed a method of treating a lithium metal anode surface such as to avoid the occurrence of unwanted chemical reactions in a battery. The lithium metal anode surface is treated using the material according to the invention. The method according to the invention involves use of a protective material which comprises a metal fluoride such as aluminum trifluoride (AlF3) and a fluoro alkylene carbonate such as fluoroethylene carbonate (FEC). The method comprises forming a coat of the protective material on the surface of the lithium metal anode. The invention thus provides the following in accordance with aspects thereof: (1) Material for protecting a lithium metal sheet, comprising a metal fluoride and a fluoro alkylene carbonate.(2) The material according to (1), wherein the metal fluoride is selected from the group consisting of AlF3 and ZnF2.(3) The material according to (1) or (2), wherein the fluoro alkylene carbonate comprises a C2-15 fluoro alkylene group which is straight or branched; or the fluoro alkylene carbonate comprises a C2-6 fluoro alkylene group; optionally the fluoro alkylene carbonate is cyclic.(4) Material for protecting a lithium metal sheet, comprising AlF3 and fluoro ethylene carbonate (FEC).(5) The material according to any one of (1) to (3), wherein the metal fluoride and the fluoro alkylene carbonate are present in amounts of about 1 g and about 0.5-5 mL, respectively; or in amounts of about 1 g and about 2 mL, respectively; or in amounts of about 1 g and about 3 mL, respectively; or in amounts of about 1 g and about 1 mL, respectively; or in amounts of about 1 g and about 0.5 mL, respectively.(6) The material according to (4), whe