Thin film for anode of lithium secondary battery and manufacturing method thereof

• US 20050074673A1
• Filed: 11/29/2004
• Published: 04/07/2005
• Est. Priority Date: 08/25/2001
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Park, Young-sin, Lee, Sung-man, Oh, Joo-yeal, Baik, Hong-koo
• Granted Patent: US 7,316,867 B2
• Time in Patent Office: Days
• US Class Current: 429/231.950
• CPC Class Codes: H01M 10/0436 Small-sized flat cells or batteries for portable equipment
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0562 Solid materials
• 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 4/1391 of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/1397 of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• CPC Class Codes: H01M 4/366 as layered products
• 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 4/525 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 4/54 of silver
• 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

A thin film for an anode of a lithium secondary battery having a current collector and an anode active material layer formed thereon is provided. The anode active material layer is a multi-layered thin film formed by stacking a silver (Ag) layer and a silicon-metal (Si—M) layer having silicon dispersed in a base made from metal reacting with silicon while not reacting with lithium. The cycle characteristic of the thin film for an anode can be improved by suppressing the volumetric expansion and shrinkage of Si occurring during charging/discharging cycles. Thus, a lithium secondary battery with improved life characteristics by employing the thin film for an anode, which greatly improves the chemical, mechanical stability of the interface between an electrode and an electrolyte.

Claims

1. A thin film for an anode of a lithium secondary having a current collector and an anode active material layer formed on the current collector, wherein the anode active material layer is a multi-layered thin film formed by stacking a silver (Ag) layer and a silicon-metal (Si—

M) layer having silicon dispersed in a base made from metal reacting with silicon while not reacting with lithium.

2. The thin film for an anode according to claim 1, wherein the metal (M) is at least one selected from the group consisting of vanadium (V), manganese (Mn), titanium (Ti), nickel (Ni), platinum (Pt), zirconium (Zr), chromium (Cr), iron (Fe), hafnium (Hf), molybdenum (Mo), niobium (Nb), ruthenium (Ru) and tantalum (Ta).

3. The thin film for an anode according to claim 1, wherein the metal (M) content in the Si—

M layer as the anode active material layer is in the range of 5 to 50 mol %.

4. The thin film for an anode according to claim 3, wherein the metal (M) content in the Si—

M layer as the anode active material layer is in the range of 20 to 30 mol %.

5. The thin film for an anode according to claim 1, wherein a buffering layer made from at least one metal selected from the group consisting of V, Ni, Mo and Cu is formed between the current collector and the anode active material layer.

6. The thin film for an anode according to claim 5, wherein the thickness of the buffering layer is in the range of 50 to 250 Å

.

7. The thin film for an anode according to claim 1, wherein the thickness of the Si—

M layer is in the range of 50 to 450 Å and

the thickness of the Ag layer is in the range of 10 to 70 Å

.

8. The thin film for an anode according to claim 1, wherein the Si—

M layer and the Ag layer are alternately formed.

9. The thin film for an anode according to claim 8, wherein the Ag layer is disposed between Si—

M layers.

10. The thin film for an anode according to claim 1, wherein the topmost layer of the multi-layered thin film is made from Ag.

11. A method of manufacturing a thin film for an anode of a lithium secondary battery comprising:

(a) forming a thin film of silicon-metal (Si—

M) by depositing a metal reacting with silicon while not reacting with lithium and silicon on a current collector in forms of thin films;

(b) forming a thin film of silver (Ag) by depositing Ag on the Si—

M layer in form of a thin film; and

(c) forming a multi-layered thin film by repeating the steps (a) and (b) more than one time.

12. The method according to claim 11, wherein the metal (M) is at least one selected from the group consisting of vanadium (V), manganese (Mn), titanium (Ti), nickel (Ni), platinum (Pt), zirconium (Zr), chromium (Cr), iron (Fe), hafnium (Hf), molybdenum (Mo), niobium (Nb), ruthenium (Ru) and tantalum (Ta).

13. The method according to claim 11, wherein the metal (M) content in the Si—

M layer as the anode active material layer is in the range of 5 to 50 mol %.

14. The method according to claim 11, wherein deposition in steps (a) and (b) is performed by a method selected from co-sputtering, e-beam evaporation and ion-beam assisted deposition.