Particles containing a non-conducting or semi-conducting nucleus covered with a hybrid conducting layer, their processes of preparation and uses in electrochemical devices

Patent metadata

Field	Value
Publication number	US-9870873-B2
Application number	US-201414220716-A
Country	US
Kind code	B2
Filing date	Mar 20, 2014
Priority date	Jul 12, 2002
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

Mixture of particles comprising a non-conducting or semi-conducting nucleus covered with a hybrid conductor coating and hybrid conductor chains located between the particles of the mixture to constitute a conductivity network, that is prepared by mechanical crushing. Due to a very good conductivity of the network, a low resistivity, a very good capacity under elevated current and/or a good density of energy, these mixtures of particles are advantageously incorporated in anodes and cathodes of electrochemical generators, resulting in highly performing electrochemical systems.

First claim

The invention claimed is:

1. Mixture of particles comprising a non-conducting or semi-conducting nucleus, the nuclei of said particles being at least partially covered with a hybrid conductor coating and said particles being at least partially connected through hybrid conducting chains which provide a network of electrical conductivity, wherein:
the nucleus of said particles is at least 65% of one lithium oxide selected from the group consisting of oxides of the formula:
Li 4 Ti 5 O 12 ;
Li (4-α) Z α Ti 5 O 12 , in which 0<α≦0.33, Z represents a source of at least one metal; and
Li 4 Z β Ti (5-β) O 12 in which 0<β≦0.5, Z represents at least one metal;

each of the hybrid conductor coating and the hybrid conducting chains is a hybrid carbon mixture which comprises at least two different conducting forms of carbon, which are hereunder designated Carbon 1 and Carbon 2, wherein:
Carbon 1 consists of particles with low crystallinity having a d002 greater than 3.36 Å if measured by X-ray diffraction or by Raman spectroscopy, said Carbon 1 possesses a specific surface area which, as measured by the BET method, is equal to or greater than 50 m 2 /g, and particles of Carbon 1 have an average size varying from 10 to 999 nm, and
Carbon 2 consists of at least one of graphite particles and high crystallinity carbon particles with high crystallinity having a d002 smaller than 3.36 Å if measured by X-ray diffraction, particles of Carbon 2 have a specific surface area which, as measured by the BET method, is equal to or smaller than 50 m 2 /g, and the particles of Carbon 2 have a size varying from 2 to 10 μm,

wherein the hybrid conductor coating comprises:
a first, inner coating of Carbon 1 which covers between 50 and 90% of the surface of the nucleus, and
a second, outer coating of Carbon 2.

2. Mixture of particles according to claim 1 , in which the second, outer coating of Carbon 2 comprises particles are connected together to constitute an electrical conductivity network.

3. Mixture according to claim 1 , in which the particles have a D 50 of about 7 micrometers.

4. Mixture according to claim 1 , in which Z represents a particle of a metal selected from the group consisting of Mg, Nb, Al, Zr, Ni and Co.

5. Mixture according to claim 1 , containing from 1 to 6% by weight of carbon in said mixture.

6. Mixture according to claim 5 , containing about 2% by weight of carbon in said mixture.

7. Mixture according to claim 1 , in which Carbon 2 is at least one graphite selected from the group consisting of synthetic graphite, natural graphite, exfoliated graphite and mixtures of two or more of these graphite.

8. Mixture according to claim 1 , in which the weight percentage of Carbon 1 represents from 1 to 10% of the total weight of the coating composed of Carbon 1 and Carbon 2.

9. Mixture according to claim 1 , in which the quantity of Carbon 1 is substantially identical to the quantity of Carbon 2.

10. Mixture according to claim 1 , in which the average diameter of the nucleus of said particles varies from 50 nanometers to 30 micrometers.

11. Mixture according to claim 10 , wherein the average diameter of said nucleus is of the order of about 2 micrometers.

12. Mixture according to claim 1 , in which the average size of said particles, measured according to the electronic scanning microscope method, is between 4 and 30 micrometers.

13. Mixture according to claim 1 , having at least one of the following properties: a very good local conductivity, a very good network conductivity, a low resistivity, a very good capacity under elevated current and a good density of energy.

14. Mixture according to claim 11 , having a local conductivity, measured according to the four point method, that is higher than 10 −6 (Ohm-m).

15. Mixture of particles according to claim 13 , having a network conductivity, measured according to the four point method, that is between 2.6×10 −3 and 6.2×10 −3 .

16. Cathode for electrochemical generator comprising a mixture of particles as defined in claim 1 .

17. Anode for electrochemical generator comprising particles as defined in claim 1 .

18. Electrochemical generator of the lithium type including at least one metallic lithium anode and at least one cathode as defined in claim 16 .

19. Electrochemical generator according to claim 18 , preferably of the rechargeable and/or recyclable type.

20. Electrochemical generator of the lithium type including at least one metallic lithium anode as defined in claim 16 , at least one cathode and comprising at least one electrolyte.

21. Electrochemical generator according to claim 18 , in which at least one anode and/or at least one cathode are provided with an aluminum current collector that is full or of the Exmet type (expanded metal).

22. Electrochemical generator according to claim 18 requiring no previous preparation of the battery.

23. Generator according to claim 18 , in which the electrolyte is a dry polymer, a gel, a liquid or a ceramic.

24. Electrochemical system according to claim 18 , wherein the electrode is prepared without any addition of additional carbon.

25. Mixture according to claim 1 , in which at least some of the particles of Carbon 2 are connected together to constitute an electrical conductivity network.

26. Mixture according to claim 1 , in which about 80% of Carbon 1 is covering the surface of said nuclei; and about 20% of the particles of Carbon 2 are connected together to constitute an electrical conductivity network.

27. Mixture according to claim 1 , in which the nucleus of said particles consists for at least 70% of at least one metal oxide.

28. Mixture according to claim 11 , having a local conductivity, measured according to the four point method, that is higher than or equal to 10 −5 (Ohm-m).

29. Mixture of particles according to claim 13 , having a network conductivity, measured according to the four point method, that is lower than about 6.0×10 −03 (Ohm-m).

30. Electrochemical generator according to claim 18 , in which the anode is of the Li 4 Ti 5 O 12 and/or Li (4-α) Z α Ti 5 O 12 and/or Li 4 Z β Ti (5-β) O 12 type.

31. Electrochemical generator according to claim 18 , in which the anode is of the Li 4 Ti 5 O 12 and/or Li (4-α) Z α Ti 5 O 12 and/or Li 4 Z β Ti (5-β) O 12 type; and the cathode is of the LiFePO 4 , LiCoO 2 , LiMn 2 O 4 and/or LiNiO 2 type.

Assignees

• Hydro Quebec

Inventors

• Zaghib Karim
• Charest Patrick
• Guerfi Abdelbast
• Perrier Michel
• Kinoshita Kimio

Classifications

• H01M4/366

  as layered products · CPC title

• H01M4/131

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

• H01M10/052

  Li-accumulators · CPC title

• H01M4/661

  Metal or alloys, e.g. alloy coatings (H01M4/669 take precedence) · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title