Anode for Li-ion battery

Patent metadata

Field	Value
Publication number	US-12199287-B2
Application number	US-201917263721-A
Country	US
Kind code	B2
Filing date	Jul 25, 2019
Priority date	Jul 27, 2018
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

The invention relates to an anode for a Li-ion rechargeable battery, said anode being covered with a protective film based on fluorinated copolymer(s). The invention also relates to the processes for preparing this anode. The invention also relates to a Li-ion rechargeable battery comprising an anode according to the invention. The invention lastly relates to the use of fluorinated copolymer(s) as film for covering an anode for a lithium-ion battery comprising a negative electrode active material.

First claim

The invention claimed is:

1. Anode for lithium-ion battery, comprising a negative electrode active material, said anode being covered with a film comprising at least one copolymer chosen from:
the copolymer comprising vinylidene fluoride and trifluoroethylene units of formula P(VDF-TrFE),
the copolymer comprising vinylidene fluoride and tetrafluoroethylene units of formula P(VDF-TFE), and
a fluorinated terpolymer chosen from: the terpolymer comprising vinylidene fluoride, trifluoroethylene and chlorofluoroethylene units of formula P(VDF-TrFE-CFE), the terpolymer comprising vinylidene fluoride, trifluoroethylene and chlorotrifluoroethylene units of formula P(VDF-TrFE-CTFE), the terpolymer comprising vinylidene fluoride, trifluoroethylene and hexafluoropropylene units of formula P(VDf-TrFE-HFP), the terpolymer comprising vinylidene fluoride, tetrafluoroethylene and chlorofluoroethylene units of formula P(VDF-TFE-CFE), the terpolymer comprising vinylidene fluoride, tetrafluoroethylene and chlorotrifluoroethylene units of formula P(VDF-TFE-CTFE), and the terpolymer comprising vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene units of formula P(VDf-TFE-HFP),
or a blend chosen from: the blend of P(VDF-TrFE) copolymer with the P(VDF-TFE) copolymer; the blend of P(VDF-TrFE) copolymer with one of the aforementioned terpolymers; the blend of P(VDF-TFE) copolymer with one of the aforementioned terpolymers, and the blend of two terpolymers among the aforementioned ones;
in which the negative electrode active material is an alkali metal.

2. Anode according to claim 1 , in which the negative electrode active material is lithium.

3. Anode according to claim 1 , in which said film has a thickness ranging from 1 to 14 μm, limits included.

4. Anode according to claim 1 , in which said film has a density ranging from 1.2 to 2 g/cm 3 .

5. Anode according to claim 1 , in which, when the fluorinated film deposited on said negative electrode active material is formed of a blend of a copolymer and a terpolymer, these are present in a weight ratio of from 50:50 to 1:99.

6. Anode according to claim 1 , in which, in the copolymer of formula P(VDF-TrFE), the proportion of units derived from trifluoroethylene is less than 55 mol % and greater than 18 mol % relative to the sum of the units derived from vinylidene fluoride and from trifluoroethylene.

7. Anode according to claim 1 , in which, in the copolymer of formula P(VDF-TFE), the proportion of units derived from tetrafluoroethylene is less than 60 mol % and greater than 10 mol % relative to the sum of the units derived from vinylidene fluoride and from tetrafluoroethylene.

8. Anode according to claim 1 , in which the molar ratio of the VDF units to the TrFE or TFE units in the terpolymers has a value of from 85/15 to 30/70.

9. Anode according to claim 1 , in which the proportion of units derived from the CFE, HFP or CTFE monomer is from 1 to 15 mol %, relative to all of the units of a terpolymer.

10. Process for manufacturing a negative electrode comprising a layer of negative electrode active material covered with a film of fluorinated copolymer(s) according to claim 1 , said process comprising a step of depositing said film of fluorinated copolymer(s) on the surface of said negative electrode active material.

11. Process according to claim 10 , in which the deposition of the film takes place via a solvent route.

12. Process according to claim 10 comprising a step consisting in dissolving the fluorinated copolymer or the fluorinated terpolymers in a solvent selected from the group consisting of carbonates, carbamates, nitriles, amides, sulfoxides, sulfolane, nitromethane, 1,3-dimethyl-2-imidazolidinone, 1,3-dimethyl-3,4,5,6-tetrahydro-2 (1,H)-pyrimidinone, 3-methyl-2-oxazolidinone, and mixtures thereof.

13. Process according to claim 10 , in which the deposition of the film takes place via a dry route.

14. Li-ion rechargeable battery comprising the negative electrode according to claim 1 , a positive electrode and an electrolyte.

15. A film for covering an anode for a lithium-ion battery comprising a negative electrode active material, the film comprising a copolymer chosen from:
the copolymer comprising vinylidene fluoride and trifluoroethylene units of formula P(VDF-TrFE),
the copolymer comprising vinylidene fluoride and tetrafluoroethylene units of formula P(VDF-TFE), and
a fluorinated terpolymer chosen from: the terpolymer comprising vinylidene fluoride, trifluoroethylene and chlorofluoroethylene units of formula P(VDF-TrFE-CFE), the terpolymer comprising vinylidene fluoride, trifluoroethylene and chlorotrifluoroethylene units of formula P(VDF-TrFE-CTFE), the terpolymer comprising vinylidene fluoride, trifluoroethylene and hexafluoropropylene units of formula P(VDf-TrFE-HFP), the terpolymer comprising vinylidene fluoride, tetrafluoroethylene and chlorofluoroethylene units of formula P(VDF-TFE-CFE), the terpolymer comprising vinylidene fluoride, tetrafluoroethylene and chlorotrifluoroethylene units of formula P(VDF-TFE-CTFE), and the terpolymer comprising vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene units of formula P(VDf-TFE-HFP),
or of a blend chosen from: the blend of P(VDF-TrFE) copolymer with the P(VDF-TFE) copolymer; the blend of P(VDF-TrFE) copolymer with one of the aforementioned terpolymers; the blend of P(VDF-TFE) copolymer with one of the aforementioned terpolymers, and the blend of two terpolymers among the aforementioned ones;
wherein the film is configured to inhibit the formation of lithium dendrites within the negative electrode active material.

16. Anode according to claim 1 , wherein the at least one copolymer has a melt flow index between 0.1 and 100.

17. The film according to claim 15 , wherein the copolymer has a melt flow index between 0.1 and 100.

Assignees

• Arkema France

Inventors

• Plee Dominique
• Domingues Dos Santos Fabrice
• Schmidt Gregory

Classifications

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/382

  Lithium (H01M4/405 takes precedence) · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/1395

  of electrodes based on metals, Si or alloys · CPC title

• H01M4/134 Primary

  Electrodes based on metals, Si or alloys · CPC title