Conductive composite material of graphene, preparation method therefor, use thereof and lithium-ion battery

Patent metadata

Field	Value
Publication number	US-12281016-B2
Application number	US-202118246866-A
Country	US
Kind code	B2
Filing date	Sep 27, 2021
Priority date	Sep 28, 2020
Publication date	Apr 22, 2025
Grant date	Apr 22, 2025

Abstract

A conductive composite material of graphene contains graphene nano-sheets and conjugated copolymers. The conjugated copolymers has alkynyl groups and are in a linear structure and grafted to the graphene nano-sheets. The preparation of conductive composite material includes the steps of: pretreating the graphene nano-sheets with 4-bromobenzenediazonium tetrafluoroborate, and forming the conjugated copolymers in the presence of the pretreated graphene nano-sheets. The conductive composite material of graphene can be uniformly dispersed in an electrode slurry, reduce the internal resistance of an electrode, and improve the electrical conductivity of an electrode. At the same time, the flexible structure associated with the graphene nano-sheets can buffer the volume expansion of the silicon-containing negative materials during charge-discharge cycling. Such a composite material can be in a lithium-ion battery.

First claim

The invention claimed is:

1. A conductive composite material of graphene, comprising graphene nano-sheets and a conjugated copolymer, wherein the conjugated copolymer comprises alkynyl groups, has a linear structure, and is grafted to the graphene nano-sheets,
wherein the graphene nano-sheets are low-layer graphene comprising 3-5 layers of graphene,
wherein the graphene nano-sheets involve in their Raman spectrum a D peak and a G peak which have the peak heights of Ip and IG, respectively, whereinwhere I D /I G is 0.03-0.30, and
wherein the conductive composite material of graphene has a conductivity of 200-800 S/cm.

2. The conductive composite material of graphene according to claim 1 , wherein the conductive composite material of graphene has a specific surface area of 50-300m 2 /g.

3. The conductive composite material of graphene according to claim 2 , wherein the conductive composite material of graphene has a specific surface area of 100-250 m 2 /g.

4. The conductive composite material of graphene according to claim 1 , wherein, based on a total amount of the conductive composite material of graphene, the graphene nano-sheets are present in an amount of 85%-99% by mass, and the conjugated copolymer is present in an amount of 1%-15% by mass.

5. The conductive composite material of graphene according to claim 1 , wherein the graphene nano-sheets has plane dimensions of 0.05-5.0 μm.

6. The conductive composite material of graphene according to claim 1 , wherein the conjugated copolymer is one or more copolymer selected from copolymers of arylalkyne, copolymers of fluorene, copolymers of p-phenylenevinylene, copolymers of p-phenyleneethynylene, copolymers of thiophene, copolymers of thiophene derivatives, copolymers of pyrrole and copolymers of pyrrole derivatives.

7. A method for preparing the conductive composite material of graphene according to claim 1 , comprising the steps of:
pretreating the graphene nano-sheets with 4-bromobenzenediazonium tetrafluoroborate; and
forming the conjugated copolymer in the presence of the pretreated graphene nano-sheets.

8. The method according to claim 7 , wherein the pretreating comprises the steps of:
under stirring, dripping an aqueous solution of 4 -bromobenzenediazonium tetrafluoroborate into an aqueous dispersion of the graphene nano-sheets, and treating at a temperature of −5° C. to 40° C. for 30-180 min, then drying to obtain the pretreated graphene nano-sheets.

9. The method according to claim 8 , wherein the aqueous solution of 4-bromobenzenediazonium tetrafluoroborate has a concentration of 40%-70% by mass, and the graphene nano-sheets are present in a concentration of 5%-50% by mass in the aqueous dispersion of the graphene nano-sheets.

10. The method according to claim 9 , wherein the monomers comprise at least a first monomer containing halogen and a second monomer comprises an alkynyl group.

11. The method according to claim 9 , wherein the catalyst is at least one selected from palladium catalysts and nickel catalysts.

12. The method according to claim 9 , wherein the polymerizing is carried out under in an inert atmosphere and at a temperature of 80-150° C. for 12 h to 36 h.

13. The method according to claim 8 , wherein 4-bromobenzenediazonium tetrafluoroborate and the graphene nano-sheets are in a mass ratio of 3-6:1.

14. The method according to claim 8 , wherein the drying is drying in vacuum at a temperature of 60-80° C. for 2-10 h.

15. The method according to claim 7 , wherein the forming the conjugated copolymer comprising polymerizing monomers in the presence of a catalyst, a solvent, and the pretreated graphene nano-sheets to obtain the conductive composite material of graphene.

16. A lithium-ion battery, comprising the conductive composite material of graphene according to claim 1 .

17. The conductive composite material of graphene according to claim 1 , wherein the conjugated copolymer is one or more copolymer selected from arylalkyne, copolymers of fluorene, copolymers of thiophene, and copolymers of thiophene derivatives.

18. The conductive composite material of graphene according to claim 1 , wherein the conjugated copolymer is one or more copolymer selected from poly (l,4-dialkynylbenzene-co-triphenylamine), poly (1,4-dialkynylbenzene-co-9-hexylfluorene), poly (1,4-dialkynylbenzene-co-3-hexylthiophene), poly (1,4-dialkynylbenzene-co-thiophene), and poly (1,4-dialkynylbenzene-co-3,4-ethylene dioxy thiophene).

Assignees

• China Petroleum & Chem Corp
• Shanghai Res Inst Petrochemical Tech Sinopec

Inventors

• Sun Sai
• Zhang Siyu
• Dong Wenqian
• Gao Huanxin

Classifications

• H01M10/0525

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

• H01M4/625 Primary

  Carbon or graphite · CPC title

• C01P2004/24

  Nanoplates, i.e. plate-like particles with a thickness from 1-100 nanometer · CPC title

• C01P2004/03

  obtained by SEM · CPC title

• C01P2002/82

  by IR- or Raman-data · CPC title