Lithium secondary battery

Patent metadata

Field	Value
Publication number	US-9570777-B2
Application number	US-201214347978-A
Country	US
Kind code	B2
Filing date	Sep 28, 2012
Priority date	Sep 29, 2011
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A lithium secondary battery of the present invention includes: a positive electrode; a negative electrode; a nonaqueous electrolytic solution; and a separator. The positive active material contains a lithium-containing composite oxide containing nickel. A molar ratio of a total nickel amount with respect to a total lithium amount contained in the entire positive active material is 0.05 to 1.0. The nonaqueous electrolytic solution contains 0.5 to 5.0 mass % of a phosphonoacetate-based compound represented by the following General Formula (1). In the Formula, R 1 , R 2 , and R 3 independently represent an alkyl group, an alkenyl group, or an alkynyl group having 1 to 12 carbon atoms, which may be substituted by a halogen atom, and “n” represents an integer of 0 to 6.

First claim

The invention claimed is:

1. A lithium secondary battery, comprising: a positive electrode; a negative electrode; a nonaqueous electrolytic solution; and a separator,
wherein the positive electrode includes a collector and a positive electrode material mixture layer formed on the collector,
the positive electrode material mixture layer includes a positive active material, a conductive agent, and a binder,
the positive active material contains a lithium-containing composite oxide containing nickel,
wherein a molar ratio of a total nickel amount with respect to a total lithium amount contained in the entire positive active material is 0.05 to 1.0, and
the nonaqueous electrolytic solution contains 0.5 to 5.0 mass % of a phosphonoacetate-based compound represented by the following General Formula (1):

in the General Formula (1), R 1 and R 2 independently represent an alkyl group, an alkenyl group, or an alkynyl group having 1 to 12 carbon atoms, which may be substituted by a halogen atom, R 3 represents an alkynyl group, and “n” represents an integer of 0 to 6.

2. The lithium secondary battery according to claim 1 , wherein the lithium-containing composite oxide is represented by a general composition formula: Li 1+y MO 2 ,
in the general composition formula, “y” satisfies a relationship: −0.15≦y≦0.15, and “M” represents an element group including Ni, Co, and Mn, and
the following relationships: 25≦a≦90, 5≦b≦35, 5≦c≦35, and 10≦b+c≦70 are satisfied, where a (mol %), b (mol %), and c (mol %) respectively represent a ratio of the number of elements of Ni, Co, and Mn included in the element group M with respect to the total number of elements included in the element group M.

3. The lithium secondary battery according to claim 1 , wherein the positive active material further contains another lithium-containing composite oxide containing a transition metal other than nickel.

4. The lithium secondary battery according to claim 3 , wherein the molar ratio is 0.15 to 1.0.

5. The lithium secondary battery according to claim 1 , wherein the positive active material contains the lithium-containing composite oxide containing nickel in a ratio of 10 to 80 mass %.

6. The lithium secondary battery according to claim 1 , wherein the positive electrode material mixture layer has a density of 3.7 g/cm 3 or more.

7. The lithium secondary battery according to claim 1 , wherein the positive electrode material mixture layer contains carbon fibers having an average fiber length of 10 to 1000 nm and an average fiber diameter of 1 to 100 nm as the conductive agent.

8. The lithium secondary battery according to claim 1 , wherein the positive electrode material mixture layer contains polyvinylidene fluoride and a tetrafluoroethylene-vinylidenefluoride copolymer as the binder.

9. The lithium secondary battery according to claim 1 , wherein the negative electrode includes a collector and a negative electrode material mixture layer formed on the collector,
the negative electrode material mixture layer contains a negative active material, and
the negative active material contains a composite of a material containing silicon and oxygen as constituent elements and a carbon material.

10. The lithium secondary battery according to claim 9 , wherein the negative active material further contains a graphitic carbon material.

11. The lithium secondary battery according to claim 1 , wherein a charge voltage is 4.3 V or more.

12. The lithium secondary battery according to claim 1 , wherein the phosphonoacetate-based compound is 2-propynyl(diethylphosphono)acetate.

13. The lithium secondary battery according to claim 1 , wherein the separator includes a porous layer (I) containing a resin having a melting point of 140° C. or less as a main component, and a porous layer (II) containing a resin that is not melted at a temperature of 150° C. or less or an inorganic filler having a heat-resistant temperature of 150° C. or more as a main component.

14. The lithium secondary battery according to claim 1 , wherein a charge voltage is 4.35 V or more.

Assignees

• Hitachi Maxell
• Ube Industries

Inventors

• Kamizori Haruki
• Nakamura Yusuke
• Gosho Itaru
• Yamada Masayuki
• Abe Koji
• Shimamoto Kei

Classifications

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M2300/0025

  Organic electrolyte · CPC title

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• H01M4/525 Primary

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• Y02T10/7011

  Cross-Sectional Technologies · mapped topic