Carbon compound-adsorbed cathode active material and lithium battery using the same

• US 7,314,683 B2
• Filed: 02/06/2004
• Issued: 01/01/2008
• Est. Priority Date: 02/07/2003
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Choi, Young-min, Ham, Yong-nam, Park, Jung-joon
• Primary Examiner(s): Ryan; Patrick Joseph
• Assistant Examiner(s): Parsons; Thomas H.
• Application Number:
  US10/772,290
• Publication Number:
  US 20040157127A1
• Time in Patent Office: 1,425 Days
• Field of Search: 429/231.1, 429/231.8, 429/61, 429/53, 429/223, 429/221, 429/224, 429/231.3
• US Class Current: 429/231.1
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• 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 4/364 as mixtures
• 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 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: H01M 4/623 fluorinated polymers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A cathode active material is prepared by mixing a transition metal compound and a lithium compound in a molar ratio of 1:1.0-1:1.2 and thermally treating the mixture while supplying CO₂ and O₂ in a ratio of partial pressures ranging from 1:0.001-1:1,000, and a lithium battery utilizes the cathode active material. The lithium battery ensures safety against over-charging because an overflow of current may be effectively cut off without reducing discharging capacity and cycle life characteristics.

Claims

1. A cathode active material comprising:

a lithium transition metal composite oxide in which a carbon compound is adsorbed to obtain a carbon content of 10-1,000 ppm.

2. The cathode active material of claim 1, wherein the lithium transition metal composite oxide is at least one selected from the group consisting of LiNiO₂, LiCoO₂, LiMn₂O₄, LiFePO₄, LiNi_xCo_1-xO₂ where 0<

x<

1, and LiNi_1-x-yCo_xMn_yO₂ where 0<

x<

1, 0<

y<

1, and 0<

x+y<

1.

3. The cathode active material of claim 1, wherein the carbon compound has a specific surface area of 10-5,000 m²/g.

4. A lithium battery comprising:

a cathode comprising;

a cathode active material that comprises a lithium transition metal composite oxide in which a carbon compound is adsorbed to obtain a carbon content of 10-1,000 ppm;

an anode comprising a carbonaceous material to facilitate intercalating and deintercalating lithium ions;

a separator interposed between the cathode and the anode;

an electrolytic solution containing an electrolytic solute dissolved in a nonaqueous solvent; and

a current cut-off device that operates in response to a rise in an internal pressure of the lithium battery.

5. The lithium battery of claim 4, wherein the carbon compound has a specific surface area of 10-5,000 m²/g.

6. The lithium battery of claim 4, wherein the separator is selected from the group consisting of a glass fiber, polyester, polyethylene, polypropylene, polytetrafluoroethylene, and a combination of thereof.

7. A lithium battery comprising:

a cathode comprising;

a cathode active material that comprises a lithium transition metal composite oxide in which a carbon compound is adsorbed to obtain a carbon content of 10-1,000 ppm and wherein the lithium transition metal composite oxide is at least one selected from the group consisting of LiNiO₂, LiCoO₂, LiMn₂O₄, LiFePO₄, LiNi_xCo_1-xO₂ where 0<

x<

1, and LiNi_1-x-yCo_xMn_yO₂ where 0<

x<

1, 0<

y<

1, and 0<

x+y<

1;

an anode comprising a carbonaceous material to facilitate intercalating and deintercalating lithium ions;

a separator interposed between the cathode and the anode;

an electrolytic solution containing an electrolytic solute dissolved in a nonaqueous solvent; and

a current cut-off device that operates in response to a rise in an internal pressure of the lithium battery.

8. The lithium battery of claim 7, wherein a polymer resin is utilized as a binding agent for the anode and the cathode, and wherein the polymer resin is a vinylidenefluoride-hexafluoropropylene copolymer having 8-25% by weight of hexafluoropropylene.