Electrode formulations comprising graphenes

Patent metadata

Field	Value
Publication number	US-9722248-B2
Application number	US-201314405793-A
Country	US
Kind code	B2
Filing date	Jun 19, 2013
Priority date	Jun 20, 2012
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

Disclosed herein are cathode formulations comprising graphenes. One embodiment provides a cathode formulation comprising an electroactive material, and graphene interspersed with the electroactive material, wherein a ratio of (mean electroactive material domain size)/(mean graphene lateral domain size) ranges from 3:2 to 15:1. Also disclosed are cathodes comprising such materials and methods of making such cathodes.

First claim

The invention claimed is:

1. A cathode formulation comprising:
an electroactive material; and
graphene interspersed with the electroactive material;
wherein a ratio of (mean electroactive material domain size)/(mean graphene lateral domain size) ranges from 3:2 to 15:1, and
wherein the cathode formulation is in the form of a paste or a slurry.

2. The cathode formulation of claim 1 , wherein the electroactive material has a domain size ranging from 3 to 20 μm.

3. The cathode formulation of claim 1 , wherein the graphene has a BET surface area ranging from 80 to 800 m 2 /g.

4. The cathode formulation of claim 1 , wherein the graphene is a 2-20 layer graphene.

5. The cathode formulation of claim 1 , wherein the graphene has a mean lateral domain size ranging from 0.5 to 10 μm.

6. The cathode formulation of claim 1 , wherein the ratio of (mean electroactive material domain size)/(mean graphene lateral domain size) ranges from 3:2 to 10:1.

7. The cathode formulation of claim 1 , wherein the electroactive material is a lithium ion-based material.

8. The cathode formulation of claim 1 , wherein the graphene is present in an amount ranging from 0.1 to 2.5% by weight relative to the total weight of the cathode formulation.

9. A cathode, comprising:
an electroactive material; and
graphene interspersed with the electroactive material;
wherein a ratio of (mean electroactive material domain size)/(mean graphene lateral domain size) ranges from 3:2 to 15:1.

10. The cathode of claim 9 , wherein the graphene is present in the cathode in an amount ranging from 0.1 to 2.5% by weight relative to the total weight of the cathode.

11. The cathode of claim 9 , wherein the cathode has a performance, as defined by a discharge capacity at 4 C current, of at least 130 mAh/g.

12. The cathode of claim 9 , further comprising a binder.

13. The cathode of claim 12 , wherein the binder is selected from fluorinated polymers such as poly(vinyldifluoroethylene) (PVDF), poly(vinyldifluoroethylene-co-hexafluoropropylene) (PVDF-HFP), poly(tetrafluoroethylene) (PTFE), polyimides, and water-soluble binders such as poly(ethylene) oxide, polyvinyl-alcohol (PVA), cellulose, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinyl pyrrolidone (PVP), polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), and fluoro rubber, and copolymers and mixtures thereof.

14. The cathode of claim 9 , wherein the graphene is a 2-20 layer graphene having a mean lateral domain size ranging from 0.5 to 10 μm.

15. The cathode of claim 9 , wherein the electroactive material is a lithium ion-based material.

16. A method of making a cathode, comprising:
combining particles comprising an electroactive material, a graphene, and a binder in the presence of a solvent to produce a paste having a solids loading of at least 65% by weight, wherein a ratio of (mean electroactive material domain size)/(mean graphene lateral domain size) ranges from 3:2 to 15:1; and
depositing the paste onto a substrate; and
forming the cathode.

17. The method of claim 16 , wherein the combining comprises adding a sufficient amount of particles to achieve a solids loading of at least 80% by weight.

18. The method of claim 16 , wherein the forming comprises removing the solvent.

19. A cathode paste containing particles comprising:
an electroactive material;
a graphene; and
a binder;
wherein a ratio of (mean electroactive material domain size)/(mean graphene lateral domain size) ranges from 3:2 to 15:1, and
wherein the paste has a solids loading of at least 65% by weight.

20. The cathode paste of claim 19 , wherein the viscosity of the paste ranges from 100 cP to 10,000 cP.

Assignees

• Cabot Corp

Inventors

• Hardman Ned J
• Blizanac Berislav
• Dupasquier Aurelien L
• Oljaca Miodrag
• Kyrlidis Agathagelos

Classifications

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/623

  fluorinated polymers · CPC title

• H01M4/364

  as mixtures · CPC title

• H01M4/587 Primary

  for inserting or intercalating light metals · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title