Lithium secondary battery including multi-layered active material layers

Patent metadata

Field	Value
Publication number	US-9318738-B2
Application number	US-201414468645-A
Country	US
Kind code	B2
Filing date	Aug 26, 2014
Priority date	May 23, 2013
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A lithium secondary battery of the present invention may simultaneously improve high output and high capacity characteristics by including a first active material layer having high output characteristics and a second active material layer having high capacity characteristics respectively on a cathode collector and an anode collector.

First claim

The invention claimed is:

1. A lithium secondary battery comprising:
(1) a cathode in which a cathode collector; a first cathode active material layer including a spinel-structured lithium manganese oxide active material on at least one surface of the cathode collector; and a second cathode active material layer including a layer-structured lithium composite oxide active material on the first cathode active material layer are sequentially formed; and
(2) an anode in which an anode collector; a first anode active material layer including an amorphous carbon-based active material on at least one surface of the anode collector; and a second anode active material layer including at least one selected from the group consisting of a silicon (Si)-based material, and a tin (Sn)-based material on the first anode active material layer are sequentially formed,
wherein the silicon (Si)-based material comprises any one selected from the group consisting of single Si; a Si—C composite formed by mechanical alloying of Si and a carbonaceous material; a composite formed by mechanical alloying of Si and metal; a carbon-Si nanocomposite; Si coated with Si oxide and carbon, or Si oxide; and a mixture of two or more thereof.

2. The lithium secondary battery of claim 1 , wherein the spinel-structured lithium manganese oxide active material comprises LiMn 2 O 4 or LiCoMn 2 O 4 .

3. The lithium secondary battery of claim 1 , wherein the layer-structured lithium composite oxide active material is expressed by Chemical Formula 1 or Chemical Formula 2:
<Chemical Formula 1>
Li[Ni x Co y Mn z M v ]O 2
(where M is any one selected from the group consisting of aluminum (Al), gallium (Ga), indium (In), and a mixture of two or more elements thereof; and 0.3≦x<1.0, 0≦y, z≦0.5, 0≦v≦0.1, and x+y+z+v=1)
<Chemical Formula 2>
Li(Li a M b-a-b′ M′ b′ )O 2-c A c

(where 0≦a≦0.2, 0.6≦b≦1, 0≦b′≦0.2, and 0≦c≦0.2; M includes manganese (Mn), and a least one selected from the group consisting of nickel (Ni), cobalt (Co), iron (Fe), chromium (Cr), vanadium (V), copper (Cu), zinc (Zn), and titanium (Ti); M′ is at least one selected from the group consisting of Al, magnesium (Mg), and boron (B); and A is at least one selected from the group consisting of phosphorous (P), fluorine (F), sulfur (S), and nitrogen (N)).

4. The lithium secondary battery of claim 1 , wherein the amorphous carbon-based active material is obtained from at least one amorphous carbon precursor selected from the group consisting of hard carbon raw materials including sucrose, a phenol resin, a naphthalene resin, a polyvinyl alcohol resin, a furfuryl alcohol resin, a polyacrylonitrile resin, a polyamide resin, a furan resin, a cellulose resin, a styrene resin, a polyimide resin, an epoxy resin, or a vinyl chloride resin; and soft carbon raw materials including a coal-based pitch, a petroleum-based pitch, polyvinyl chloride, a mesophase pitch, tar, or heavy oil.

5. The lithium secondary battery of claim 1 , wherein a thickness ratio of the first cathode active material layer:the second cathode active material layer is in a range of 50:50 to 10:90.

6. The lithium secondary battery of claim 5 , wherein the thickness ratio of the first cathode active material layer:the second cathode active material layer is in a range of 50:50 to 30:70.

7. The lithium secondary battery of claim 1 , wherein a thickness ratio of the first anode active material layer:the second anode active material layer is in a range of 50:50 to 10:90.

8. The lithium secondary battery of claim 7 , wherein the thickness ratio of the first anode active material layer:the second anode active material layer is in a range of 50:50 to 30:70.

9. The lithium secondary battery of claim 1 , wherein a net density of the first cathode active material layer is in a range of 4.0 g/cc to 4.3 g/cc, and a net density of the second cathode active material layer is in a range of 4.5 g/cc to 4.9 g/cc.

10. The lithium secondary battery of claim 1 , wherein a net density of the first anode active material layer is in a range of 1.9 g/cc to 2.15 g/cc, and a net density of the second anode active material layer is in a range of 2.15 g/cc to 2.3 g/cc.

11. The lithium secondary battery of claim 1 , wherein a specific surface area of the first cathode active material layer is in a range of 0.4 m 2 /g to 0.5 m 2 /g, and a specific surface area of the second cathode active material layer is in a range of 0.5 m 2 /g to 0.6 m 2 /g.

12. The lithium secondary battery of claim 1 , wherein a specific surface area of the first anode active material layer is in a range of 2 m 2 /g to 2.7 m 2 /g, and a specific surface area of the second anode active material layer is in a range of 2.8 m 2 /g to 3.5 m 2 /g.

13. The lithium secondary battery of claim 1 , wherein a charge and discharge capacity of the first cathode active material layer is in a range of 100 mAh/g to 119 mAh/g, and a charge and discharge capacity of the second cathode active material layer is in a range of 120 mAh/g to 200 mAh/g.

14. The lithium secondary battery of claim 1 , wherein a charge and discharge capacity of the first anode active material layer is in a range of 200 mAh/g to 310 mAh/g, and a charge and discharge capacity of the second anode active material layer is in a range of 300 mAh/g to 400 mAh/g.

15. The lithium secondary battery of claim 1 , wherein the first cathode active material layer and the first anode active material layer are coated by die coating, and the second cathode active material layer and the second anode active material layer are coated by nozzle coating.

16. A lithium secondary battery comprising:
(1) a cathode in which a cathode collector; a first cathode active material layer including a spinel-structured lithium manganese oxide active material on at least one surface of the cathode collector; and a second cathode active material layer including a layer-structured lithium composite oxide active material on the first cathode active material layer are sequentially formed; and
(2) an anode in which an anode collector; a first anode active material layer including an amorphous carbon-based active material on at least one surface of the anode collector; and a second anode active material layer including transition metal oxide on the first anode active material layer are sequentially formed,
wherein the transition metal oxide comprises any one selected from the group consisting of SnO 2 , Fe 2 O 3 , Fe 3 O 4 , NiO, CoO, Co 2 O 3 , CO 3 O 4 , Sn 1-x Ti x O 2 (x=0.1 to 0.9), Zn 2 SnO 4 , CoSnO 3 , CaSnO 3 , ZnCo 2 O 4 , Co 2 SnO 4 , Mg 2 SnO 4 , Mn 2 SnO 4 , and a mixture of two or more thereof.

17. The lithium secondary battery of claim 16 , wherein the spinel-structured lithium manganese oxide active material comprises LiMn 2 O 4 or LiCoMn 2 O 4 .

18. The lithium secondary battery of claim 16 , wherein the layer-structured lithium composite oxide active material is expressed by Chemical Formula 1 or Chemical Formula 2:
<Chemical Formula 1>
Li[Ni x Co y Mn z M v ]O 2
(where M is any one selected from the group consisting of aluminum (Al), gallium (Ga), indium (In), and a mixture of two or more elements thereof; and 0.3≦x<1.0, 0≦y, z≦0.5, 0≦v≦0.1, and x+y+z+v=1)
<Chemical Formula 2>
Li(Li a M b-a-b′ M′ b′ )O 2-c A c

(where 0≦a≦0.2, 0.6≦b≦1, 0≦b′≦0.2, and 0≦c≦0.2; M includes manganese (Mn), and a least one selected from the group consisting of nickel (Ni), cobalt (Co), iron (Fe), chromium (Cr), vanadium (V), copper (Cu), zinc (Zn), and titanium (Ti); M′ is at least one selected f

Assignees

• Lg Chemical Ltd

Inventors

• Kim Ji Sun
• Youn Min Ho
• Shin Dong Seok
• Park Hyo Seok

Classifications

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M4/387

  Tin or alloys based on tin · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title