Porous anode active material, method of preparing the same, and anode and lithium battery employing the same

• US 8,562,869 B2
• Filed: 09/23/2011
• Issued: 10/22/2013
• Est. Priority Date: 12/19/2006
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Mah, Sang-kook, Kim, Han-su, Im, Dong-min
• Primary Examiner(s): Kopec, Mark
• Assistant Examiner(s): THOMAS, JAISON P
• Application Number:
  US13/243,039
• Publication Number:
  US 20120013051A1
• Time in Patent Office: 760 Days
• Field of Search: 252/506, 252/510, 429/231.95, 264/29.1, 264/621
• US Class Current: 252/506
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/1393 of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/364 as mixtures
• CPC Class Codes: H01M 4/38 of elements or alloys
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/387 Tin or alloys based on tin
• CPC Class Codes: H01M 4/42 Alloys based on zinc
• CPC Class Codes: H01M 4/466 Magnesium based
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Provided are a porous anode active material, a method of preparing the same, and an anode and a lithium battery employing the same. The porous anode active material includes fine particles of metallic substance capable of forming a lithium alloy; a crystalline carboneous substance; and a porous carboneous material coating and attaching to the fine particles of metallic substance and the crystalline carboneous substance, the porous anode active material having pores exhibiting a bimodal size distribution with two pore diameter peaks as measured by a Barrett-Joyner-Halenda (BJH) pore size distribution from a nitrogen adsorption. The porous anode active material has the pores having a bimodal size distribution, and thus may efficiently remove a stress occurring due to a difference of expansion between a carboneous material and a metallic active material during charging and discharging. Further, the anode electrode and the lithium battery comprising the anode active material have excellent charge/discharge characteristics.

Claims

1. A method of preparing a porous anode active material, comprising:

preparing a solution containing fine silicon particles, graphite particles, a carbon precursor, and a surfactant;

drying and thermally curing the solution while stirring it to obtain a gelling material; and

sintering the gelling material.

2. The method of claim 1, wherein the concentration of the surfactant in the solution is 10-300 parts by weight, based on 100 parts by weight of the carbon precursor.

3. The method of claim 1, wherein the carbon precursor is a low molecular weight substance having a molecular weight less than 200 or an oligomer substance having a molecular weight of 500-5000.

4. The method of claim 1, wherein the carbon precursor is at least one compound selected from the group consisting of phenol, resorcinol, formaldehyde, and acetaldehyde and oligomers thereof.

5. The method of claim 1, wherein the surfactant is a compound having any one of formulae 1 to 3:

(EO)_l-(PO)_m-(EO)_n 

 

(1)

wherein

EO is ethylene oxide,

PO is propylene oxide,

each of l, m and n is a real number of 5-200,

C_pH_2p+1(OC₂H₄)_rOH 

 

(2)

wherein

each of p and r is a real number of 5-100,

CH₃C(CH₃)₂CH₂C(CH₃)₂C₆H₄(OC₂H₄)_sOH 

 

(3)

wherein

s is a real number of 5-100.

6. The method of claim 1, wherein the surfactant is at least one compound selected from the group consisting of (EO)₁₀₆-(PO)₇₀-(EO)₁₀₆, (EO)₁₀₀-(PO)₃₉-(EO)₁₀₀, (EO)₈₀-(PO)₃₀-(EO)₈₀, (EO)₅-(PO)₇₀-(EO)₅, (EO)₂₀-(PO)₇₀-(EO)₂₀, and (EO)₂₀-(PO)₃₀-(EO)₂₀.

7. The method of claim 1, wherein the fine silicon particles are capped with an organic amine.

8. The method of claim 1, wherein the graphite particles are pretreated with an acid.

9. The method of claim 1, wherein the carbon precursor is sintered at a temperature ranging from a carbonization temperature of the carbon precursor to 1400°

C.