# US 10,312,523 B2 · Lithium ion secondary battery

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- Number: US 10,312,523 B2
- Document ID: US10312523B2
- Status: Granted
- Kind: B2
- Application number: 15/437,978
- Filed: 2017-02-21
- Published: 2017-08-31
- Granted: 2019-06-04
- Earliest claimed: 2016-02-25
- Assignees: TDK Corporation
- Applicants: TDK Corporation
- Inventors: Atsushi Sano; Keitaro Otsuki
- Web page: https://patentgrep.com/patent/US10312523B2

## CPC

- H01M 4/628: {Inhibitors, e.g. gassing inhibitors, corrosion inhibitors}
- H01M 4/13: Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M 4/131: Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 4/364: {as mixtures}
- 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 4/5825: {Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/0569: characterised by the solvents
- H01M 4/386: {Silicon or alloys based on silicon}
- 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

A lithium ion secondary battery includes: a positive electrode including a positive electrode active material layer; a negative electrode; and an electrolyte. The positive electrode active material layer contains Lia(M)b(PO4)c (M=VO or V, 0.9≤a≤3.3, 0.9≤b≤2.2, 0.9≤c≤3.3) as a first positive electrode active material, and additionally contains a fluorine compound of 1 to 300 ppm in terms of fluorine with respect to a weight of the positive electrode active material layer.

## Claims

### Claim 1

A lithium ion secondary battery comprising:
a positive electrode including a positive electrode active material layer;
a negative electrode; and
an electrolyte, wherein
the positive electrode active material layer contains Lia(M)b(PO4)c (M=VO or V, 0.9≤a≤3.3, 0.9≤b≤2.2, 0.9≤c≤3.3) as a first positive electrode active material, and additionally contains a fluorine compound of 1 to 300 ppm in terms of fluorine with respect to a weight of the positive electrode active material layer, and
the fluorine compound is present only in a region from a surface to a depth of 100 nm of the positive electrode active material layer.

### Claim 2 (depends on 1)

The lithium ion secondary battery according to claim 1, wherein
the fluorine compound is lithium fluoride.

### Claim 3 (depends on 1)

The lithium ion secondary battery according to claim 1, wherein
the first positive electrode active material contains LiVOPO4 or Li3V2(PO4)3.

### Claim 4 (depends on 1)

The lithium ion secondary battery according to claim 1, wherein the positive electrode active material layer additionally contains LiNixCoyMnzMaO2 (x+y+z+a=1, 0≤x≤1, 0≤y≤1, 0≤z≤1, and 0≤a≤1, where M is one or more elements selected from Al, Mg, Nb, Ti, Cu, Zn, and Cr) as a second positive electrode active material.

### Claim 5 (depends on 4)

The lithium ion secondary battery according to claim 4, wherein
the positive electrode active material layer contains 1 to 30 wt % of the first positive electrode active material with respect to a sum of the first positive electrode active material and the second positive electrode active material.

### Claim 6 (depends on 1)

The lithium ion secondary battery according to claim 1, comprising 4-fluoroethylene carbonate as the electrolyte.

### Claim 7 (depends on 1)

The lithium ion secondary battery according to claim 1, wherein
the negative electrode contains at least one or more selected from silicon and silicon oxide as a negative electrode active material.