Composite Particle for Electrode, Method for Producing the Same and Secondary Battery

• US 20080160409A1
• Filed: 08/23/2005
• Published: 07/03/2008
• Est. Priority Date: 08/26/2004
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Otsuka, Takashi, Matsuda, Hiroaki, Ishida, Sumihito, Yoshizawa, Hiroshi, Kogetsu, Yasutaka, Asari, Takuma
• Application Number:
  US11/596,182
• Publication Number:
  US 20080160409A1
• Time in Patent Office: Days
• US Class Current: 429/220
• CPC Class Codes: B01J 21/08 Silica
• CPC Class Codes: B01J 21/185 Carbon nanotubes carbon nanotubes per se C01B32/15
• CPC Class Codes: B01J 23/38 of noble metals
• CPC Class Codes: B01J 23/70 of the iron group metals or copper
• CPC Class Codes: B01J 23/74 Iron group metals
• CPC Class Codes: B01J 23/75 Cobalt
• CPC Class Codes: B01J 23/755 Nickel
• CPC Class Codes: B01J 23/78 with alkali- or alkaline earth metals
• CPC Class Codes: B01J 23/8892 Manganese
• CPC Class Codes: B01J 35/23 in a colloidal state
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 2202/34 Length
• CPC Class Codes: C01B 2202/36 Diameter
• CPC Class Codes: C01B 32/162 characterised by catalysts
• CPC Class Codes: D01F 9/127 by thermal decomposition of hydrocarbon gases or vapours or other carbon-containing compounds in the form of gas or vapour, e.g. carbon monoxide, alcohols
• CPC Class Codes: D01F 9/1271 Alkanes or cycloalkanes
• CPC Class Codes: D01F 9/1272 Methane
• CPC Class Codes: D01F 9/1273 Alkenes, alkynes
• CPC Class Codes: H01G 11/22 Electrodes
• CPC Class Codes: H01G 11/24 : characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor
• CPC Class Codes: H01G 11/34 : characterised by carbonisation or activation of carbon
• CPC Class Codes: H01G 11/36 : Nanostructures, e.g. nanofibres, nanotubes or fullerenes
• CPC Class Codes: H01G 11/46 : Metal oxides
• CPC Class Codes: H01M 10/052 : Li-accumulators
• CPC Class Codes: H01M 4/131 : Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/139 : Processes of manufacture
• CPC Class Codes: H01M 4/366 : as layered products
• CPC Class Codes: H01M 4/505 : of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 : of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/625 : Carbon or graphite
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02E 60/13 : Energy storage using capacitors

Abstract

A composite particle for an electrode including an active material particle, carbon nanofibers bonded to the surface of the active material particle, and a catalyst element for promoting the growth of the carbon nanofibers, wherein the active material particle includes an electrochemically active phase. As the catalyst element, for example, Au, Ag, Pt, Ru, Ir, Cu, Fe, Co, Ni, Mo, Mn and the like are used. The composite particle for an electrode may be produced, for example, by means of a method which includes: a step of preparing an active material particle including a catalyst element for promoting the growth of carbon nanofibers at least in the surface layer of the active material particle; and a step of growing carbon nanofibers on the surface of the active material particle in an atmosphere including a raw material gas.

Claims

1. A composite particle for an electrode comprising an active material particle, carbon nanofibers bonded to the surface of said active material particle and a catalyst element for promoting the growth of the carbon nanofibers, wherein said active material particle comprises an electrochemically active phase.

2. The composite particle for an electrode according to claim 1, wherein said catalyst element is at least one selected from the group-consisting of Au, Ag, Pt, Ru, Ir, Cu, Fe, Co, Ni, Mo and Mn.

3. The composite particle for an electrode according to claim 1, wherein said catalyst element is located at least in the surface layer of said active material particle or at the tip of said carbon nanofibers.

4. The composite particle for an electrode according to claim 1, wherein said catalyst element is present in a state of a metal particle and/or a metal oxide particle of 1 nm to 1000 nm in particle size in the surface layer of said active material particle.

5. The composite particle for an electrode according to claim 1, wherein at least one end of said carbon nanofibers is chemically bonded to the surface of said active material particle.

6. The composite particle for an electrode according to claim 1, wherein said carbon nanofibers have a fiber length of 1 nm to 1 mm.

7. The composite particle for an electrode according to claim 1, wherein said carbon nanofibers comprise fibers of 1 nm to 40 nm in fiber diameter.

8. The composite particle for an electrode according to claim 1, wherein said carbon nanofibers comprise at least one selected from the group consisting of tubular carbon, accordion-shaped carbon, plate-shaped carbon and herringbone-shaped carbon.

9. The composite particle for an electrode according to claim 1, wherein said electrochemically active phase comprises at least one metal or semimetal element selected from the group consisting of the elements of the 3B, 4B and 5B groups in the periodic table, and the phase comprising said metal or semimetal element is a compound, an alloy or an elementary substance thereof.

10. The composite particle for an electrode according to claim 9, wherein said compound is at least one selected from the group consisting of an oxide, a nitride, an oxynitride, a carbide and a sulfide.

11. The composite particle for an electrode according to claim 9, wherein said metal or semimetal element is at least one selected from the group consisting of Si, Sn and Ge, and said compound is at least one selected from the group consisting of an oxide, a nitride and an oxynitride.

12. The composite particle for an electrode according to claim 1, wherein said active material particle comprises a core formed of an elementary substance of at least one metal or semimetal element selected from the group consisting of the elements of the 3B, 4B and 5B groups in the periodic table, and an oxide layer covering the surface of said core.

13. The composite particle for an electrode according to claim 1, wherein said electrochemically active phase is formed of a lithium-containing transition metal oxide having-a layered-structure, and said lithium-containing transition metal oxide comprises at least one metal element selected from the group consisting of Cu, Fe, Co, Ni, Mo and Mn.

20. A secondary battery comprising a chargeable and dischargeable positive electrode, a chargeable and dischargeable negative electrode, and a non-aqueous electrolyte, wherein at least one of said positive electrode and said negative electrode comprises the composite particle according to claim 1.

21. An electrochemical capacitor comprising a pair of polarizable electrodes, a separator interposed between the two electrodes and an aqueous or non-aqueous electrolyte, wherein said polarizable electrodes comprise the composite particle according to claim 1.

14. A method for producing a composite particle for an electrode, the method comprising:

a step A of preparing an active material particle comprising an electrochemically active phase and having, at least on the surface thereof, a catalyst element for promoting the growth of carbon nanofibers;

a step B of growing the carbon nanofibers on the surface of said active material particle in an atmosphere comprising a carbon-containing gas; and

a step C of baking said active material particle with the carbon nanofibers bonded thereto at 400°

C. or higher and 1600°

C. or lower in an inert gas atmosphere.

15. The method for producing a composite particle for an electrode according to claim 14, wherein the step A comprises a step of supporting, on the surface of the particle comprising an electrochemically active phase, a particle comprising at least one metal element selected from the group consisting of Au, Ag, Pt, Ru, Ir, Cu, Fe, Co, Ni, Mo and Mn.

16. The method for producing a composite particle for an electrode according to claim 14, wherein the step A comprises a step of reducing the surface of the particle comprising the electrochemically active phase including at least one metal element selected from the group consisting of Cu, Fe, Co, Ni, Mo and Mn.

17. The method for producing a composite particle for an electrode according to claim 14, wherein the step A comprises a step of synthesizing a particle of an alloy of at least one metal or semimetal element selected from the group consisting of the elements of the 3B, 4B and 5B groups in the periodic table and at least one metal element selected from the group consisting of Cu, Fe, Co, Ni, Mo and Mn.

18. The method for producing a composite particle for an electrode according to claim 14, further comprising a step of heat treating in air, after the step C, said composite particle at 100°

C. or higher and 400°

C. or lower.

19. The method for producing a composite particle for an electrode according to claim 14, wherein said catalyst element is Ni, said carbon-containing gas is ethylene, and said carbon nanofibers are of a herringbone shape.

22. A method for producing a composite particle for an electrode, the method comprising:

a step of supporting on the surface of an active material a catalyst element for promoting the growth of carbon nanofibers; and

a step of growing carbon nanofibers on the surface of said active material by bringing the active material that supports said catalyst element into contact with a raw material gas, wherein;

said active material comprises an oxide;

said raw material gas is a carbon-containing gas or a mixed gas composed of a carbon-containing gas and hydrogen gas;

said carbon-containing gas is at least one selected from the group consisting of carbon monoxide (CO), a saturated hydrocarbon gas represented by C_nH_2n+2 (n≧

1), an unsaturated hydrocarbon gas represented by C_nH_2n (n≧

2) and an unsaturated hydrocarbon gas represented by C_nH<sub>2n−

2</sub> (n≧

2); and

the content of said hydrogen gas accounts for less than 5% by volume of said mixed gas.

23. The method for producing a composite particle for an electrode according to claim 22, wherein the surface layer of said active material comprises an oxide.

24. The method for producing a composite particle for an electrode according to claim 22, wherein said catalyst element is at least one selected from the group consisting of Au, Ag, Pt, Ru, Ir, Cu, Fe, Co, Ni, Mo and Mn.

25. The method for producing a composite particle for an electrode according to claim 22, wherein the carbon nanofibers bonded to the surface of said active material are grown by introducing said raw material gas and said active material that supports the catalyst element into a reaction vessel, and by maintaining the temperature inside said reaction vessel at 400 to 750°

C.

26. The method for producing a composite particle for an electrode according to claim 25, wherein said reaction vessel is formed of at least one material selected from the group consisting of cast iron, carbon and alumina.

27. The method for producing a composite particle for an electrode according to claim 22, wherein the active material that supports said catalyst element in a state of a salt or a compound is brought into contact with said raw material gas.