Binder for an electrode of an electrochemical system, electrode comprising this binder, and electrochemical system comprising this electrode

Patent metadata

Field	Value
Publication number	US-9673480-B2
Application number	US-52619008-A
Country	US
Kind code	B2
Filing date	Feb 8, 2008
Priority date	Feb 9, 2007
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

Binder for an electrode of an electrochemical system having a non-aqueous electrolyte, said binder comprising a first polymer which has functional groups capable of reacting with a crosslinking agent and is crosslinked with said crosslinking agent, the crosslinked first polymer forming a three-dimensional network in which a second polymer chosen from fluoropolymers is imprisoned.

First claim

The invention claimed is:

1. Binder for an electrode of an electrochemical system having a non-aqueous electrolyte, said binder comprising a first polymer having functional groups bonded with a crosslinking agent, and the first polymer is crosslinked with the crosslinking agent, the crosslinked first polymer forming a three-dimensional network in which a second polymer chosen from fluoropolymers is imprisoned, wherein the binder comprises 2 to 5% by weight of the crosslinking agent relative to the weight of the first polymer, and wherein the first polymer is different from the second polymer.

2. Binder according to claim 1 , in which said functional groups bonded with a crosslinking agent are chosen from hydroxyl functional groups, amide functional groups, carboxylic acid functional groups and esters thereof.

3. Binder according to claim 2 , in which the first polymer is a hydroxylated polymer soluble in organic medium, whether said polymer is crosslinked or not, and capable of being obtained by hydrolysis of a non-hydroxylated polymer miscible with the fluoropolymers.

4. Binder according to claim 3 , in which said hydroxylated polymer is chosen from polyvinyl alcohols (PVAs), vinyl alcohol/vinyl acetate (PVA-co-PVAc) copolymers, and blends thereof.

5. Binder according to claim 4 , in which the PVA-co-PVAC copolymers have a degree of hydrolysis of 5% to 99%.

6. Binder according to claim 4 , in which the PVA-co-PVAC has a weight-average molecular weight of 5000 to 600 000 g/mol.

7. Binder according to claim 1 , in which the crosslinking agent is chosen from dialdehyde compounds.

8. Binder according to claim 7 , in which the crosslinking agent is chosen from: aliphatic dialdehydes and aromatic dialdehydes.

9. Binder according to claim 8 , in which the first polymer is a PVA-co-PVAC and the polymer crosslinked with the crosslinking agent satisfies the following formula:

in which R represents:

where n is an integer from 0 to 10.

10. Binder according to claim 1 , in which the second polymer is chosen from vinylidene fluoride polymers (PVDFs), vinylidene fluoride copolymers and blends thereof.

11. Binder according to claim 1 , comprising from 10 to 90% by weight of the first polymer and from 10 to 90% by weight of the second polymer relative to the total weight of the binder.

12. Electrode for an electrochemical system having a non-aqueous electrolyte, comprising a binder according to claim 1 , an electrochemically active material, optionally one or more electronically conductive additives and a current collector.

13. Electrode according to claim 12 , which is a positive electrode of a rechargeable electrochemical accumulator having a non-aqueous electrolyte.

14. Electrode according to claim 13 , in which the electrochemically active material is chosen from: LiCoO 2 ; compounds derived from LiCoO 2 , these being obtained by substitution LiMn 2 O 4 ; LiNiO 2 ; compounds derived from LiMn 2 O 4 , these being obtained by substitution LiMnO 2 ; compounds derived from LiMnO 2 , these being obtained by substitution olivines LiFePO 4 , Li 2 FeSiO 4 , LiMnPO 4 and LiCoPO 4 ; hydrated or non-hydrated iron phosphates and sulphates; LiFe 2 (PO 4 ) 3 ;
hydrated or non-hydrated vanadyl phosphates and sulphates Li 1+x V 3 O 8 ( 0 <x< 4 ); Li x V 2 O 5 ·nH 2 O ( 0 <x< 3 and 0 <n< 2 ); and mixtures thereof.

15. Electrode according to claim 12 , which is a negative electrode of a rechargeable electrochemical accumulator having a non-aqueous electrolyte.

16. Electrode according to claim 15 , in which the electrochemically active material is chosen from: carbon-based compounds; lithium alloys of the Li x M type where M=Sn, Sb or Si; Li x Cu 6 Sn 5 compounds where 0 <x< 13 ; iron borates; reversibly decomposable simple oxides; pnicures; insertion oxides; and mixtures thereof.

17. Electrode according to any one of claims 12 to 16 , in which the electronically conductive additive is chosen from: metal particles; graphite; carbon black; carbon fibres; carbon nanowires and carbon nanotubes; and electronically conductive polymers and mixtures thereof.

18. Electrochemical system comprising at least one electrode according to claim 12 .

19. Ink, comprising, in a solvent, from 70 to 90% by weight of active material, optionally from 1 to 15% by weight of one or more electronically conductive additives and from 1 to 20% by weight of the binder according to claim 1 .

20. Binder according to claim 4 , in which the PVA-co-PVAC copolymers have a degree of hydrolysis of 5% to 95%.

21. Binder according to claim 8 , in which the aliphatic dialdehydes are chosen from ethanedial and glutaraldehyde.

22. Binder according to claim 8 , in which the aromatic dialdehydes are chosen from ortho-phthalaldehyde, meta-phthalaldehyde, para-phthalaldehyde, 2,6-pyridinedicarbaldehyde and 2,5-thiophenedicarbaldehyde.

23. Binder according to claim 10 , in which the vinylidene fluoride copolymers are chosen from poly(vinylidene fluoride/hexafluoropropylene) (PVDF-HFP).

24. Electrode according to claim 1 , in which the compounds derived from LiCoO 2 are obtained by substitution with Al, Ti, Mg, Ni or Mn.

25. Electrode according to claim 24 , in which the compounds derived from LiCoO 2 are LiAl x Ni y Co( 1−x−y )O 2 or LiNi x Mn x Co 1−2x O 2 , where x <0.5 and y <1.

26. Electrode according to claim 1 , in which the compounds derived from LiMn 2 O 4 are obtained by substitution with Al, Ni or Co.

27. Electrode according to claim 14 , in which the compounds derived from LiMnO 2 are obtained by substitution with Al, Ni, Co, Fe, Cr or Cu.

28. Electrode according to claim 27 , in which the compound derived from LiMnO 2 is LiNi 0.5 O 2.

29. Electrode according to claim 14 , in which the hydrated or non-hydrated vanadyl phosphates and sulphates are VOSO 4 ·nH 2 O or Li x VOPO 4 ·nH 2 O (0<x<3 and 0<n<2).

30. Electrode according to claim 16 , in which the reversibly decomposable simple oxides are CoO, Co 2 O 3 or Fe 2 O 3.

31. Electrode according to claim 16 , in which the pnicures are Li( 3−x−y )Co y N, Li( 3 −x−y )Fe y N, Li x MnP 4 , Li x FeP 2 or Li x FeSb 2.

32. Electrode according to claim 16 , in which the insertion oxides are TiO 2 , Li 4 Ti 5 O 12 , Li x NiP 2 , Li x NiP 3 , MoO 3 or WO 3.

33. Electrode according to claim 16 , in which the carbon-based compounds are natural or synthetic graphites and disordered carbons.

34. Electrode according to claim 17 , in which the metal particles are Ag particles.

Assignees

• Medlege Franck
• Rouault Helene
• Belgacem Naceur
• Blayo Anne
• Inst Nat Polytechnique De Grenoble
• Commissariat Energie Atomique

Inventors

• Medlege Franck
• Rouault Helene
• Belgacem Naceur
• Blayo Anne

Classifications

• H01M4/622

  being polymers · CPC title

• H01M4/623

  fluorinated polymers · CPC title

• H01M10/0525 Primary

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

• H01M4/139

  Processes of manufacture · CPC title

• H01M4/621

  Binders · CPC title