Cathode active material, cathode and nonaqueous secondary battery

Patent metadata

Field	Value
Publication number	US-9350022-B2
Application number	US-201414575082-A
Country	US
Kind code	B2
Filing date	Dec 18, 2014
Priority date	May 22, 2009
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

A cathode active material of the present invention is a cathode active material having a composition represented by General Formula (1) below,

LiFe 1-x M x P 1-y Si y O 4   (1),

where: an average valence of Fe is +2 or more; M is an element having a valence of +2 or more and is at least one type of element selected from the group consisting of Zr, Sn, Y, and Al; the valence of M is different from the average valence of Fe; 0<x≦0.5; and y=x×({valence of M}−2)+(1−x)×({average valence of Fe}−2). This provides a cathode active material that not only excels in terms of safety and cost but also can provide a long-life battery.

First claim

What is claimed is:

1. A nonaqueous secondary battery, comprising:
a cathode including:
a cathode active material;
a conductive material; and
a binder,

the cathode active material consisting of a composition represented by General Formula (1) below,
LiFe 1-x M x P 1-y Si y O 4   (1)

where:
Fe takes on a valence of +2 or +3;
an average valence of Fe is +2 or more, which average valence of Fe is an average of valences of all Fe atoms constituting the cathode active material;
M has a valence of +2 or more, and M is at least one type of element selected from the group consisting of Zr, Sn, Y, and Al;
the valence of M is different from the average valence of Fe;
0< x≦ 0.5; and
0< y< 1.0,

the conductive material being a material selected from the group consisting of acetylene black, carbon, graphite, natural graphite, artificial graphite, and needle coke.

2. The nonaqueous secondary battery according to claim 1 ,
wherein:
the binder is a material selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride, polyvinylchloride, ethylene-propylene diene polymer, styrene-butadiene rubber, acrylonitrile-butadiene rubber, fluorocarbon rubber, polyvinyl acetate, polymethyl methacrylate, polyethylene, and nitrocellulose.

3. The nonaqueous secondary battery according to claim 2 ,
wherein:
the conductive material is acetylene black;
the binder is polyvinylidene fluoride;
the acetylene black is contained at 10% to 42% by weight with respect to the cathode active material; and
the polyvinylidene fluoride is contained at 10% to 14% by weight with respect to the cathode active material.

4. The nonaqueous secondary battery according to claim 1 , further comprising:
a current collector to which a slurry has been applied that is obtained by mixing the cathode active material, the conductive material, and the binder,
the slurry including an organic solvent made of a material selected from the group consisting of N-methylpyrrolidone, toluene, cyclohexane, dimethylformamide, dimethylacetoamide, methyl ethyl ketone, methyl acetate, methyl acrylate, diethyltriamine, N—N-dimethylaminopropylamine, ethylene oxide, and tetrahydrofuran.

5. The nonaqueous secondary battery according to claim 1 , further comprising:
a current collector to which a slurry has been applied that is obtained by mixing the cathode active material, the conductive material, and the binder,
the slurry having been applied in an amount of a dry weight of 5 to 20 mg/cm 2 with respect to the current collector.

6. The nonaqueous secondary battery according to claim 1 , further comprising:
a current collector to which a slurry has been applied that is obtained by mixing the cathode active material, the conductive material, and the binder,
the current collector being made of a metal selected from the group consisting of a porous metal having continuous holes, a metal shaped in a honeycomb pattern, a sintered metal, and an expanded metal.

7. A nonaqueous secondary battery, comprising:
a cathode including a cathode active material; and
an anode including an anodic active material and a binder,
the cathode active material consisting of a composition represented by General Formula (1) below,
LiFe 1-x M x P 1-y Si y O 4   (1)

where:
Fe takes on a valence of +2 or +3;
an average valence of Fe is +2 or more, which average valence of Fe is an average of valences of all Fe atoms constituting the cathode active material;
M has a valence of +2 or more, and M is at least one type of element selected from the group consisting of Zr, Sn, Y, and Al;
the valence of M is different from the average valence of Fe;
0< x≦ 0.5; and
0< y< 1.0,

the anodic active material being either artificial graphite or natural graphite.

8. The nonaqueous secondary battery according to claim 7 ,
wherein:
the anodic active material is a graphite particle having amorphous carbon adhering to a surface thereof.

9. The nonaqueous secondary battery according to claim 7 ,
wherein:
the anode includes a conductive material; and
the conductive material is a material selected from the group consisting of acetylene black, carbon, graphite, natural graphite, artificial graphite, and needle coke.

10. The nonaqueous secondary battery according to claim 9 ,
wherein:
the conductive material is acetylene black.

11. A nonaqueous secondary battery, comprising:
a cathode including a cathode active material; and
an anode including an anodic active material and a binder, the cathode active material consisting of a composition represented by General Formula (1) below,
LiFe 1-x M x P 1-y Si y O 4   (1)

where:
Fe takes on a valence of +2 or +3;
an average valence of Fe is +2 or more, which average valence of Fe is an average of valences of all Fe atoms constituting the cathode active material;
M has a valence of +2 or more, and M is at least one type of element selected from the group consisting of Zr, Sn, Y, and Al;
the valence of M is different from the average valence of Fe;
0< x≦ 0.5; and
0< y< 1.0,

the anodic active material being Li 4 Ti 5 O 12 .

12. The nonaqueous secondary battery according to claim 11 ,
wherein:
the anode includes a conductive material; and
the conductive material is a material selected from the group consisting of acetylene black, carbon, graphite, natural graphite, artificial graphite, and needle coke.

13. The nonaqueous secondary battery according to claim 12 ,
wherein:
the conductive material is acetylene black.

Assignees

• Sharp Kk

Inventors

• Ohira Koji
• Nishijima Motoaki
• Sueki Toshitsugu
• Esaki Shogo
• Tanaka Isao
• Koyama Yukinori
• Tanaka Katsuhisa
• Fujita Koji
• Murai Shunsuke

Classifications

• H01M10/052

  Li-accumulators · CPC title

• Y02P20/133

  Renewable energy sources, e.g. sunlight · CPC title

• H01M10/0585

  of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators · CPC title

• H01M4/5825 Primary

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

• H01M10/0481

  Compression means other than compression means for stacks of electrodes and separators · CPC title