Anode active material, method of preparing the same, and anode and lithium battery containing the material

• US 8,628,884 B2
• Filed: 06/18/2010
• Issued: 01/14/2014
• Est. Priority Date: 10/17/2005
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Kim, Gue-sung, Park, Jin-hwan, Ham, Yongnam
• Primary Examiner(s): Gilliam, Barbara
• Assistant Examiner(s): MARTIN, ANGELA J
• Application Number:
  US12/818,974
• Publication Number:
  US 20100258761A1
• Time in Patent Office: 1,306 Days
• Field of Search: None
• US Class Current: 429/232
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/139 Processes of manufacture
• CPC Class Codes: H01M 4/1393 of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/1395 of electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/366 as layered products
• CPC Class Codes: H01M 4/583 Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/624 Electric conductive fillers
• CPC Class Codes: H01M 4/626 Metals
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An anode active material comprises metal core particles, metal nano wires formed on the metal core particles, pores between the metal core particles and the metal nano wires, and a carbon-based coating layer formed on a surface of the metal core particles and metal nano wires. In the anode active material according to the present invention, the metal core particles and metal nano wires are combined to form a single body, and a carbon-based coating layer is formed on the surface of the metal nano wires and metal core particles. Thus, volume changes in the pulverized metal core particles can be effectively buffered during charging and discharging, and the metal core particles are electrically connected through the metal nano wires. As a result, volume changes in the anode active material and degradation of the electrode can be prevented, thereby providing excellent initial charge/discharge efficiency and enhanced charge/discharge capacity.

Claims

1. A method of preparing an anode active material for a lithium battery, the method comprising:

mixing a metal particle powder, a polymer material and a pore-forming material to prepare a mixture;

pulverizing the mixture; and

sintering the pulverized mixture to prepare an anode active material comprising a carbonized polymer material,

wherein the metal particle powder comprises a metal selected from the group consisting of Si, Sn, Al, Ge, Pb, Bi, Sb, alloys thereof, and combinations thereof as a main component.

2. The method of claim 1, wherein the polymer material comprises a resin selected from the group consisting of vinyl resins, phenol resins, cellulose resins, pitch resins, tar resins and combinations thereof.

3. The method of claim 1, wherein the pore-forming material comprises a compound selected from the group consisting of oxalic acid, citric acid, malic acid, glycine, ammonium carbonate, ammonium bicarbonate, ammonium oxalate and combinations thereof.

4. The method of claim 1, wherein pulverizing the mixture comprises a method selected from the group consisting of high energy milling, mechano fusion and using a hammer mill.

5. The method of claim 1, wherein sintering the pulverized mixture is performed at a temperature ranging from about 500 to about 1,400°

C.

6. The method of claim 1, wherein sintering the pulverized mixture is performed at a temperature ranging from about 700 to about 1,000°

C.

7. The method of claim 1, wherein the weight ratio of the metal particle powder to the polymer material ranges from about 1:

50 to about 10;

1.

8. The method of claim 1, wherein the weight ratio of the metal particle powder to the polymer material ranges from about 1:

10 to about 5;

1.

9. The method of claim 1, wherein the metal particle powder comprises silicon, the polymer material comprises polyvinyl alcohol, the pore-forming material comprises oxalic acid, the pulverizing the mixture comprises high energy milling, and the sintering the pulverized mixture is performed at a temperature ranging from about 700 to about 1,00°

C.

10. The method of claim 1, wherein in the sintering the pulverized mixture, metal nano wires grow from the metal particle powder.