Electrode material, paste for electrodes, and lithium ion battery

Patent metadata

Field	Value
Publication number	US-9680149-B2
Application number	US-201514718725-A
Country	US
Kind code	B2
Filing date	May 21, 2015
Priority date	Jun 27, 2014
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

An electrode material includes an electrode active material having a carbonaceous film formed on a surface is used and which is capable of suppressing voltage drop when high-speed charge and discharge is carried out in a low-temperature environment.
The electrode material has a particulate shape and is formed a carbonaceous film on surfaces of electrode active material particles. An average of discharge capacity ratios between a 35C discharge capacity at −10° C. of a single particle of the electrode material and a 1C discharge capacity at −10° C. of a single particle of the electrode material is 0.50 or more.

First claim

The invention claimed is:

1. An electrode material, comprising:
electrode active material particles and a carbonaceous film provided on surfaces of the electrode active material particles, wherein the electrode active material particles having the carbonaceous film provided thereon form an electrode material having a particulate shape;
wherein an average of discharge capacity ratios between a 3C discharge capacity at −10° C. of a single particle of the electrode material and a 1C discharge capacity at −10° C. of a single particle of the electrode material is 0.50 or more,
an XRD (CuKα ray source) peak of the (002) plane derived from graphene layers in the carbonaceous film is 2Θ=25.7° or less, and
an average of plane intervals between (002) planes in the graphene layers is 0.3466 nm or more.

2. The electrode material according to claim 1 ,
wherein an inflection ratio of a lithium ion migration path in the carbonaceous film is in a range of 1.1 to 100.

3. The electrode material according to claim 1 ,
wherein the electrode active material particles have an olivine-type crystal structure.

4. The electrode material according to claim 1 ,
wherein a content rate of the carbonaceous film with respect to a total mass of the electrode material is in a range of 0.5% by mass to 5.0% by mass.

5. The electrode material according to claim 1 ,
wherein a powder resistance value of the electrode material is 300 Ω·cm or less.

6. The electrode material according to claim 1 ,
wherein a ratio between a powder resistance value (Ω·cm) of the electrode active material particles and a content rate (% by mass) of the carbonaceous film is 300 or less.

7. The electrode material according to claim 1 ,
wherein the electrode material is produced by the following steps (1) and (2),
(1) a slurry preparation step of preparing a slurry including the electrode active material particles and/or a precursor of the electrode active material particles, an organic compound i, and an organic compound ii, and
(2) a step of drying the slurry so as to generate a granulated body having a film including the organic compounds i and ii on a surface, firing the granulated body in a non-oxidative atmosphere so as to remove the organic compound ii from the film and carbonize the organic compound i, thereby forming a carbonaceous film made of a carbonaceous material coming from the organic compound i on the surface of the granulated body.

8. The electrode material according to claim 1 ,
wherein the XRD (CuKα ray source) peak of the (002) plane derived from graphene layers in the carbonaceous film is 2Θ=25.4° to 24.0°.

9. The electrode material according to claim 1 ,
wherein the average of the plane intervals between (002) planes in the graphene layers is 0.350 nm to 0.370 nm.

10. The electrode material according to claim 1 ,
wherein an average thickness of the carbonaceous film is 0.5 nm to 20 nm.

11. The electrode material according to claim 1 ,
wherein the average of discharge capacity ratios between a 3C discharge capacity at −10° C. of a single particle of the electrode material and a 1C discharge capacity at −10° C. of a single particle of the electrode material is 0.60 or more.

12. The electrode material according to claim 1 ,
wherein the average of discharge capacity ratios between a 3C discharge capacity at −10° C. of a single particle of the electrode material and a 1C discharge capacity at −10° C. of a single particle of the electrode material is in a range of 0.65 to 0.90.

13. The electrode material according to claim 1 ,
wherein an inflection ratio of a lithium ion migration path in the carbonaceous film is in a range of 1.3 to 50.

14. The electrode material according to claim 1 ,
wherein an inflection ratio of a lithium ion migration path in the carbonaceous film is in a range of 1.5 to 10.

15. The electrode material according to claim 1 ,
wherein an average thickness of the carbonaceous film is 1 nm to 10 nm.

16. The electrode material according to claim 1 ,
wherein an average thickness of the carbonaceous film is 1 nm to 5 nm.

17. The electrode material according to claim 1 ,
wherein a coating proportion of the surface of the electrode material particles with the carbonaceous film is at least 50%.

18. The electrode material according to claim 1 ,
wherein a coating proportion of the surface of the electrode material particles with the carbonaceous film is at least 80%.

19. Paste for electrodes comprising: the electrode material according to claim 1 and a binding agent.

20. A lithium ion battery comprising:
a positive electrode collector having an electrode material layer formed of the paste for electrodes according to claim 19 on a metal foil.

Assignees

• Sumitomo Osaka Cement Co Ltd

Inventors

• Kitagawa Takao
• Mine Hiroyuki
• Yasumiishi Hirofumi

Classifications

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/0471

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

• H01M10/0525

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

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title