Lithium-ion secondary battery and method of producing same

Patent metadata

Field	Value
Publication number	US-10050270-B2
Application number	US-201314399894-A
Country	US
Kind code	B2
Filing date	May 6, 2013
Priority date	May 8, 2012
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

A lithium-ion secondary battery including positive and negative electrodes, a separator element, an electrical conductor element and a binder, wherein the positive electrode includes a lithium-containing metal phosphate compound coated with a carbon material having at least one phase selected from a graphene phase and an amorphous phase, and further includes carbon black and a fibrous carbon material and wherein the negative-electrode material includes a graphite carbon material having at least one carbon phase selected from a graphene phase and an amorphous phase, and further includes carbon black and a fibrous carbon material, and wherein the binder includes a water-soluble synthetic resin or a water-dispersible synthetic resin. The most preferred positive electrode includes LiFePO4, The most preferred negative electrode includes artificial graphite or graphitazable powder. The most preferred binder is carboxyl methyl cellulose further including a surface active agent. A method of making the lithium-ion secondary battery.

First claim

The invention claimed is:

1. A lithium-ion secondary battery comprising positive and negative electrodes, a separator element, an electrical conductor element and a binder, wherein:
the positive electrode comprises a lithium-containing metal phosphate compound coated with a carbon material having at least one phase selected from a graphene phase and an amorphous phase, and further comprises conductive carbon black and a fibrous carbon mixed material,
wherein the positive electrode is prepared by a process comprising uniformly and dispersedly mixing the carbon black and lithium-containing metal phosphate compound particulates prior to blending with a dispersion of the fibrous carbon mixed material,
wherein the fibrous carbon mixed material is a mixture of a first fibrous carbon material having a fiber diameter of about 5 to 15 nm and a fiber length of about 1 to 3 μm and a second fibrous carbon material having a fiber diameter of about 70 to 150 nm and a fiber length of about 5 to 10 μm, and

wherein the first fibrous carbon material is mainly present on the surface of the lithium-containing metal phosphate particulates, and the second fibrous carbon material is mainly present between the lithium-containing metal phosphate compound particulates;
the negative-electrode material comprises a graphite material present as particulates having at least one carbon phase selected from a graphene phase and an amorphous phase, and further comprises carbon black and a fibrous carbon mixed material,
wherein the negative electrode is prepared by a process comprising uniformly and dispersedly mixing the carbon black and graphite carbon material prior to blending with a dispersion of the fibrous carbon mixed material,
wherein the fibrous carbon mixed material is a mixture of a first fibrous carbon material having a fiber diameter of about 5 to 15 nm and a fiber length of about 1 to 3 μm and a second fibrous carbon material having a fiber diameter of about 70 to 150 nm and a fiber length of about 5 to 10 μm, and
wherein the first fibrous carbon material is mainly present on the surface of the particulates of graphite material, and the second fibrous material is mainly present between the particulates of graphite material; and

the binder comprises a water-soluble synthetic resin or a water-dispersible synthetic resin.

2. A lithium-ion secondary battery according to claim 1 , wherein the lithium-containing metal phosphate compound is LiFePO 4 , LiCoPO 4 , or LiMnPO 4 .

3. A lithium-ion secondary battery according to claim 1 , wherein the lithium-containing metal phosphate compound is LiFePO 4 .

4. A lithium-ion secondary battery according to claim 1 , wherein the graphite is artificial graphite or graphitazable powder.

5. A lithium-ion secondary battery according to claim 1 , wherein the carbon black is a conductive carbon black selected from acetylene black and Ketjen black.

6. A lithium-ion secondary battery according to claim 1 , wherein the fibrous carbon material is a carbon nanotube, a carbon nanofiber or a mixture thereof.

7. A lithium-ion secondary battery according to claim 1 , wherein the water-soluble synthetic resin or a water-dispersible synthetic resin is polyacrylic acid, styrene-butadiene rubber, polyvinyl alcohol, polyvinyl acetate, polyethylene oxide, polyvinyl pyrrolidone, or polyacrylamide.

8. A lithium-ion secondary battery according to claim 1 , wherein the binder further comprises a binder dispersant.

9. A lithium-ion secondary battery according to claim 8 , wherein the binder dispersant is carboxyl methyl cellulose.

10. A lithium-ion secondary battery according to claim 1 , wherein the binder further comprises a surface active agent.

11. A lithium-ion secondary battery according to claim 10 , wherein the surface active agent is N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, or dimethyl sulfoxide.

12. A lithium-ion secondary battery according to claim 10 , wherein the surface active agent is a fatty acid, a fatty acid ester, a fatty alcohol ester, an alkoxylated alcohol, an alkoxylated amine, a fatty alcohol sulfate, a phosphate ester, an imidazolium or quaternary ammonium salt, ethylene oxide/propelene oxide, polyoxyethylenesorbitan monooleate, an anionic or nonionic surfactant, a sulfate and a sulfonate and ocytylphenol ethoxylate, a low foam surfactant, alcohol ethoxylates, nonylphenol ethoxylates and an alkyl diphenyl oxide disulfonate.

13. A lithium-ion secondary battery according to claim 10 , wherein the surface active agent is N-methyl-2-pyrrolidone.

14. A lithium-ion secondary battery according to claim 10 , wherein an amount of the surface active agent is about 0.5 to 5 mass % of an amount of the binder.

15. A lithium-ion secondary battery according to claim 1 , wherein a thickness of the coating layer is about 1 to 10 nm.

16. A lithium-ion secondary battery according to claim 1 , wherein in the positive electrode, the ratio of a total content of the carbon black and the fibrous carbon material to a total content of the coated lithium-containing metal phosphate compound is not less than about 2 mass %.

17. A lithium-ion secondary battery according to claim 1 , wherein in the negative electrode, the ratio of a total content of the carbon black and the fibrous carbon material to a total content of the coated graphite carbon material is not less than about 2 mass %.

18. A lithium-ion secondary battery according to claim 1 , wherein electronic conduction occurs between a surface the graphene phase or the amorphous phase, a surface of the carbon black and a surface of the fibrous carbon material, due to compositeness resulting from bonds between carbon atoms.

19. A method of producing a lithium-ion secondary battery as defined in claim 1 , comprising:
(a) mixing, by using a compression shear impact-type particle-compositing method, respectively, the coated lithium-containing metal phosphate compound with the carbon black, and the coated graphite carbon material with the carbon black;
(b) mixing a mixture obtained in step (a) with the fibrous carbon material dispersed in water; and
(c) mixing a mixture obtained in step (b) with a water solution in which the water-soluble resin is dissolved or with a water solution in which the water-dispersible resin is dispersed.

20. A method according to claim 19 , further comprising calcining under inert atmosphere a mixture obtained in step (b).

21. A method according to claim 20 , wherein calcination is performed at a temperature of about 700 to 850° C., for a period of about 0.5 to 2 hours.

22. A method according to claim 19 , wherein in step (c), a binder dispersant is added to the water-soluble resin or the water-dispersible resin prior to mixing with a mixture obtained in step (b).

23. A method according to claim 19 , wherein in step (c), a surface active agent is added to the water-soluble resin or the water-dispersible resin prior to mixing with a mixture obtained in step (b).

24. A method according to claim 22 , wherein the binder dispersant is carboxyl methyl cellulose.

25. A method according to claim 23 , wherein the surface active agent is added at a ratio of about 0.5 to 5 mass % of the amount of the water-soluble resin or the water-dispersible resin.

26. A method according to claim 23 , wherein the surface active agent is N-methyl-2-pyrrolidone.

27. A method according to claim 21 wherein in step (c)

Assignees

• Hydro Quebec

Inventors

• Zaghib Karim
• Saito Shinji
• Guerfi Abdelbast
• Sawai Takehiko
• Urao Kazunori
• Nakagawa Jun
• Barray Francis
• Fréchette Joël

Classifications

• H01M4/622

  being 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

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/133 Primary

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/1393

  of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title