# US 9,437,865 B2 · Active material for lithium ion secondary battery, and lithium ion secondary battery

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- Number: US 9,437,865 B2
- Document ID: US9437865B2
- Status: Granted
- Kind: B2
- Application number: 14/387,801
- Filed: 2013-03-26
- Published: 2015-03-05
- Granted: 2016-09-06
- Earliest claimed: 2012-03-27
- Assignees: TDK Corporation
- Applicants: TDK Corporation
- Inventors: Hideaki Seki; Tomohiko Kato; Hirofumi Nakano; Atsushi Sano
- Web page: https://patentgrep.com/patent/US9437865B2

## CPC

- H01M 4/131: Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 4/485: of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence)
- H01M 4/505: of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
- 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
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 2004/028: {Positive electrodes}
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

To provide an active material having high capacity and excellent cycle characteristics. An active material has a layered crystal structure and is expressed by a compositional formula (1) LiyNiaCobMncMdOx (1), where the element M is at least one kind of element selected from the group consisting of Al, Si, Zr, Ti, Fe, Mg, Nb, Ba, and V; 1.9≦(a+b+c+d+y)≦2.1; 1.05≦y≦1.35; 0<a≦0.3; 0<b≦0.25; 0.3≦c≦0.7; 0≦d≦0.1; and 1.9≦x≦2.1, and wherein 0.69≦Niβ/Niα≦0.85, where Niα is the Ni composition amount at a center portion of the active material primary particle, and Niβ is the Ni composition amount in the vicinity of a surface (in a width of 30 nm from the surface).

## Claims

### Claim 1

An active material in the form of a solid solution for lithium ion secondary battery, the active material having a layered crystal structure and expressed by a compositional formula (1) below,
LiyNiaCobMncMdOx (1) where M is at least one element selected from the group consisting of Al, Si, Zr, Ti, Fe, Mg, Nb, Ba, and V; 1.9≦(a+b+c+d+y)≦2.1; 1.05≦y≦1.35; 0<a≦0.3; 0<b≦0.25; 0.3≦c≦0.7; 0≦d≦0.1; and 1.9≦x≦2.1,
wherein 0.69≦Niβ/Niα≦0.85, where Niα is a Ni composition amount at a center portion of a primary particle of the active material, and Niβ is a Ni composition amount in a region extending from the active material surface in a depth direction by approximately 30 nm,
wherein FWHM (003) in x-ray diffraction pattern/FWHM (104) in x-ray diffraction pattern ≦0.57.

### Claim 2 (depends on 1)

The active material for lithium ion secondary battery according to claim 1, wherein the element M is Fe or V, and d is 0<d≦0.1.

### Claim 3 (depends on 1)

A lithium ion secondary battery comprising:
a positive electrode including a positive electrode collector and a positive electrode active material layer containing a positive electrode active material;
a negative electrode including a negative electrode collector and a negative electrode active material layer containing a negative electrode active material;
a separator positioned between the positive electrode active material layer and the negative electrode active material layer; and
an electrolyte in contact with the negative electrode, the positive electrode, and the separator,
wherein the positive electrode active material contains the active material according to claim 1.

### Claim 4 (depends on 2)

A lithium ion secondary battery comprising:
a positive electrode including a positive electrode collector and a positive electrode active material layer containing a positive electrode active material;
a negative electrode including a negative electrode collector and a negative electrode active material layer containing a negative electrode active material;
a separator positioned between the positive electrode active material layer and the negative electrode active material layer; and
an electrolyte in contact with the negative electrode, the positive electrode, and the separator,
wherein the positive electrode active material contains the active material according to claim 2.

### Claim 5 (depends on 1)

The active material for lithium ion secondary battery according to claim 1, wherein 1.10≦y≦1.35.

### Claim 6 (depends on 1)

The active material for lithium ion secondary battery according to claim 1, wherein 1.15≦y≦1.35.

### Claim 7 (depends on 1)

The active material for lithium ion secondary battery according to claim 1, wherein 1.20≦y≦1.35.

### Claim 8 (depends on 1)

The active material for lithium ion secondary battery according to claim 1, wherein the primary particle has an average particle diameter of 0.2 to 1.0 μm.

### Claim 9 (depends on 1)

The active material for lithium ion secondary battery according to claim 1, wherein the primary particle has an average particle diameter of 0.2 to 0.5 μm.

### Claim 10 (depends on 1)

The active material for lithium ion secondary battery according to claim 1, which has an FWHM (003) in x-ray diffraction pattern ≦0.13°.

### Claim 11 (depends on 1)

The active material for lithium ion secondary battery according to claim 1, which has an FWHM (010) in x-ray diffraction pattern ≦0.15°.

### Claim 12 (depends on 1)

The active material for lithium ion secondary battery according to claim 1, which has an FWHM (104) in x-ray diffraction pattern ≦0.20°.