ANODE AND SECONDARY BATTERY

• US 20090269677A1
• Filed: 04/23/2009
• Published: 10/29/2009
• Est. Priority Date: 04/23/2008
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Fujii, Takayuki, Hirose, Takakazu, Kawase, Kenichi, Noguchi, Kazunori, Takada, Tomoo
• Granted Patent: US 9,634,330 B2
• Time in Patent Office: Days
• US Class Current: 429/338
• 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 10/0569 characterised by the solvents
• CPC Class Codes: H01M 10/0587 of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
• CPC Class Codes: H01M 2300/0037 Mixture of solvents
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/621 Binders
• 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
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A secondary battery capable of improving the cycle characteristics is provided. The secondary battery includes a cathode, an anode, and an electrolytic solution. The electrolytic solution is impregnated in a separator provided between the cathode and the anode. The anode has an anode structure on an anode current collector. The anode structure has a structure in which a plurality of anode active material particles having silicon are held by a plurality of metal fibers forming a three-dimensional network structure. Due to the plurality of metal fibers, sufficient conductive paths are obtained among the plurality of anode active material particles. Thus, compared to a general anode in which an active material layer is provided on a current collector made of a metal foil or the like, the current collectivity is improved.

Claims

1. A secondary battery comprising:

a cathode;

an anode; and

an electrolytic solution,

wherein the anode contains a plurality of metal fibers forming a three-dimensional network structure and a plurality of anode active material particles having silicon (Si).

2. The secondary battery according to claim 1,

wherein the plurality of metal fibers are connected to each other at least partially and thereby forming the three-dimensional network structure, and

at least part of the plurality of anode active material particles is contained in the three-dimensional network structure formed from the plurality of metal fibers.

3. The secondary battery according to claim 1, wherein the metal fibers are at least one selected from the group consisting of titanium (Ti), iron (Fe), stainless, copper (Cu), aluminum (Al), zinc (Zn), silver (Ag), cobalt (Co), nickel (Ni), and chromium (Cr).

4. The secondary battery according to claim 1, wherein diameter D of the metal fibers is from 0.5 μ

m to 50 μ

m both inclusive, and ratio B/A between average cross sectional diameter A and average length B of the metal fibers is 2 or more.

5. The secondary battery according to claim 1, wherein the plurality of metal fibers form a sheet.

6. The secondary battery according to claim 5, wherein a thickness of the sheet is from 10 μ

m to 200 μ

m both inclusive, a porosity of the sheet is from 20% to 95% both inclusive, and a tensile strength of the sheet is 0.1 N/mm or more.

7. The secondary battery according to claim 1,

wherein the anode has a structure extending in one direction, and

when the metal fiber is divided into a component in the extending direction and a component in a direction orthogonal to the extending direction in a cross section along the extending direction of the anode, ratio Y/X between dimension X of the component in the extending direction and dimension Y of the component in the direction orthogonal to the extending direction is 1 or less.

8. The secondary battery according to claim 1, wherein the anode active material particles are at least one of a simple substance of silicon, a compound of silicon, and an alloy of silicon.

9. The secondary battery according to claim 1, wherein a median size of the anode active material particles is from 0.1 μ

m to 30 μ

m both inclusive.

10. The secondary battery according to claim 1, wherein a median size of the anode active material particles is from 1 μ

m to 20 μ

m both inclusive.

11. The secondary battery according to claim 1, wherein the anode contains an anode binder containing at least one resin selected from the group consisting of polyimide, polyamide, and polyamideimide, and at least part of the resin is carbonized.

12. The secondary battery according to claim 1, wherein the anode contains an anode electrical conductor containing a carbon material.

13. The secondary battery according to claim 1, wherein the anode includes an anode current collector supporting the plurality of metal fibers and the plurality of anode active material particles.

14. The secondary battery according to claim 13, wherein arithmetic average roughness Ra of a surface of the anode current collector is 0.2 μ

m or more.

15. The secondary battery according to claim 1, wherein the electrolytic solution contains a solvent containing at least one of a chain ester carbonate having halogen represented by Chemical formula 1, a cyclic ester carbonate having halogen represented by Chemical formula 2, a cyclic ester carbonate having an unsaturated bond represented by Chemical formula 3 to Chemical formula 5, sultone, and an acid anhydride:

where R11 to R16 are a hydrogen group, a halogen group, an alkyl group, or an alkyl halide group, and at least one of R11 to R16 is the halogen group or the alkyl halide group;

where R17 to R20 are a hydrogen group, a halogen group, an alkyl group, or an alkyl halide group, and at least one of R17 to R20 is the halogen group or the alkyl halide group;

where R21 and R22 are a hydrogen group or an alkyl group;

where R23 to R26 are a hydrogen group, an alkyl group, a vinyl group, or an aryl group, and at least one of R23 to R26 is the vinyl group or the aryl group;

where R27 is an alkylene group.

16. The secondary battery according to claim 15, wherein the chain ester carbonate having halogen represented by the Chemical formula 1 is fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, or bis(fluoromethyl)carbonate, the cyclic ester carbonate having halogen represented by the Chemical formula 2 is 4-fluoro-1,3-dioxolane-2-one or 4,5-difluoro-1,3-dioxolane-2-one, the cyclic ester carbonate having an unsaturated bond represented by the Chemical formula 3 is vinylene carbonate, the cyclic ester carbonate having an unsaturated bond represented by the Chemical formula 4 is vinylethylene carbonate, and the cyclic ester carbonate having an unsaturated bond represented by the Chemical formula 5 is methylene ethylene carbonate.

17. The secondary battery according to claim 1, wherein the electrolytic solution contains an electrolyte salt containing at least one selected from the group consisting of lithium hexafluorophosphate (LiPF₆), lithium tetrafluoroborate (LiBF₄), lithium perchlorate (LiClO₄), lithium hexafluoroarsenate (LiAsF₆), compounds represented by Chemical formula 6 to Chemical formula 8, and compounds represented by Chemical formula 9 to Chemical formula 11:

where X31 is a Group 1 element or a Group 2 element in the long period periodic table or aluminum (Al), M31 is a transition metal element, a Group 13 element, a Group 14 element, or a Group 15 element in the long period periodic table, R31 is a halogen group, Y31 is —

(O═

)C—

R32-C(═

O)—

, —

(O═

)C—

C(R33)₂-, or —

(O═

)C—

C(═

O)—

, R32 is an alkylene group, an alkylene halide group, an arylene group, or an arylene halide group, R33 is an alkyl group, an alkyl halide group, an aryl group, or an aryl halide group, a3 is one of integer numbers 1 to 4, b3 is 0, 2, or 4, and c3, d3, m3, and n3 are one of integer numbers 1 to 3;

where X41 is a Group 1 element or a Group 2 element in the long period periodic table, M41 is a transition metal element, a Group 13 element, a Group 14 element, or a Group 15 element in the long period periodic table, Y41 is —

(O═

)C—

(C(R41)₂)_b4-C(═

O)—

, —

(R43)₂C—

(C(R42)₂)_c4-C(═

O)—

, —

(R43)₂C—

(C(R42)₂)_c4-C(R43)₂-, —

(R43)₂C—

(C(R42)₂)_c4-S(═

O)₂—

, —

(O═

)₂S—

(C(R42)₂)_d4-S(═

O)₂—

, or —

(O═

)C—

(C(R42)₂)_d4-S(═

O)₂—

, R41 and R43 are a hydrogen group, an alkyl group, a halogen group, or an alkyl halide group, at least one of R41 and R43 is respectively the halogen group or the alkyl halide group, R42 is a hydrogen group, an alkyl group, a halogen group, or an alkyl halide group, a4, e4, and n4 are 1 or 2, b4 and d4 are one of integer numbers 1 to 4, c4 is one of integer numbers 0 to 4, and f4 and m4 are one of integer numbers 1 to 3;

where X51 is a Group 1 element or a Group 2 element in the long period periodic table, M51 is a transition metal element, a Group 13 element, a Group 14 element, or a Group 15 element in the long period periodic table, Rf is a fluorinated alkyl group with the carbon number from 1 to 10 both inclusive or a fluorinated aryl group with the carbon number from 1 to 10 both inclusive, Y51 is —

(O═

)C—

(C(R51)₂)_d5-C(═

O)—

, —

(R52)₂C—

(C(R51)₂)_d5-C(═

O)—

, —

(R52)₂C—

(C(R51)₂)_d5-C(R52)₂-, —

(R52)₂C—

(C(R51)₂)_d5-S—

(═

O)₂—

, —

(O═

)₂S—

(C(R51)₂)_e5-S(═

O)₂—

, or —

(O═

)C—

(C(R51)₂)_e5-S(═

O)₂—

, R51 is a hydrogen group, an alkyl group, a halogen group, or an alkyl halide group, R52 is a hydrogen group, an alkyl group, a halogen group, or an alkyl halide group, and at least one thereof is the halogen group or the alkyl halide group, a5, f5, and n5 are 1 or 2, b5, c5, and e5 are one of integer numbers 1 to 4, d5 is one of integer numbers 0 to 4, and g5 and m5 are one of integer numbers 1 to 3;

Chemical formula 9

LiN(C_mF_2m+1SO₂)(C_nF_2n+1SO₂)

where m and n are an integer number of 1 or more;

where R61 is a straight chain or branched perfluoro alkylene group with the carbon number from 2 to 4 both inclusive;

Chemical formula 11

LiC(C_pF_2p+1SO₂)(C_qF_2q+1SO₂)(C_rF_2r+1SO₂)

where p, q, and r are an integer number of 1 or more.

18. The secondary battery according to claim 17, wherein the compound represented by the Chemical formula 6 is a compound represented by Chemical formulas 12(1) to 12(6), the compound represented by the Chemical formula 7 is a compound represented by Chemical formulas 13(1) to 13(8), and the compound represented by the Chemical formula 8 is a compound represented by Chemical formula 14.

19. The secondary battery according to claim 1, wherein where anode utilization C (=(V1/V2)×

100;

%) is from 20% to 80% both inclusive where an insertion amount of an electrode reactant per unit area in the full charge state of the anode is V1 and an insertion amount of the electrode reactant capable of being electrochemically inserted into the anode per unit area is V2.

20. An anode containing a plurality of metal fibers forming a three-dimensional network structure and a plurality of anode active material particles having silicon (Si).