ELECTRODE MIXTURE, ELECTRODE, AND LITHIUM SECONDARY BATTERY

• US 20120315530A1
• Filed: 02/14/2011
• Published: 12/13/2012
• Est. Priority Date: 02/22/2010
• Status: Abandoned Application

• Current Assignee: Sumitomo Chemical Company Limited
• Original Assignee: Sumitomo Chemical Company Limited
• Inventors: Kageura, Jun-ichi
• Application Number:
  US13/579,794
• Publication Number:
  US 20120315530A1
• Time in Patent Office: Days
• US Class Current: 429/144
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• 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 4/505 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 4/622 being polymers
• CPC Class Codes: H01M 4/623 fluorinated polymers
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

An electrode mixture containing a lithium mixed metal oxide having a BET specific surface area of 2 to 30 m²/g, a water-soluble polymer having an acid functional group, water and an electrically conductive material. An electrode produced by applying the electrode mixture on an electrode current collector, and then drying the applied current collector. A lithium secondary battery comprising the electrode as a positive electrode.

Claims

1. An electrode mixture comprising

a lithium mixed metal oxide having a BET specific surface area of 2 to 30 m²/g,

a water-soluble polymer having an acid functional group,

water and

an electrically conductive material.

2. The electrode mixture according to claim 1, wherein the lithium mixed metal oxide is represented by the following formula (1):

Li_z(Ni_1-(x+y)Mn_xM_y)O₂ 

 

(1)

wherein x is not less than 0.3 and less than 1,

y is not less than 0 and less than 0.7,

x+y is not less than 0.3 and less than 1,

z is not less than 0.5 and not more than 1.5 and

M represents one or more elements selected from the group consisting of Co, Al, Ti, Mg and Fe.

3. The electrode mixture according to claim 1, wherein the acid functional group is one or more groups selected from the group consisting of carboxyl group, sulfo group, thiol group and phosphate group.

4. The electrode mixture according to claim 1, wherein the water-soluble polymer having an acid functional group contains one or more compounds selected from the group consisting of carboxymethyl starch, starch phosphate, algic acid, polyacrylic acid, polymethacrylic acid and polystyrene sulfonate.

5. The electrode mixture according to claim 1, further comprising one or more materials selected from the group consisting of an aqueous emulsion and an aqueous dispersion.

6. The electrode mixture according to claim 5, wherein the aqueous emulsion is one or more emulsions selected from the group consisting of an emulsion of vinyl-based polymer and an emulsion of acrylic-based polymer.

7. The electrode mixture according to claim 5, wherein the aqueous dispersion is a polytetrafluoroethylene-based dispersion.

8. The electrode mixture according to claim 1, further comprising a thickening agent.

9. The electrode mixture according to claim 8, wherein the thickening agent contains one or more compounds selected from the group consisting of methyl cellulose, carboxymethyl cellulose, polyethylene glycol, sodium polyacrylate, polyvinyl alcohol and polyvinyl pyrrolidone.

10. The electrode mixture according to claim 1, wherein the electrically conductive material contains a carbonaceous material.

11. An electrode produced by applying the electrode mixture according to claim 1 on an electrode current collector, and then drying the applied current collector.

12. A lithium secondary battery comprising the electrode according to claim 11 as a positive electrode.

13. The lithium secondary battery according to claim 12, further comprising a separator.

14. The lithium secondary battery according to claim 13, wherein the separator is a laminate film in which a heat resistant porous layer and a porous film are stacked on each other.