# US 10,312,516 B2 · Negative-electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery

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- Number: US 10,312,516 B2
- Document ID: US10312516B2
- Status: Granted
- Kind: B2
- Application number: 15/524,395
- Filed: 2016-01-18
- Published: 2018-10-04
- Granted: 2019-06-04
- Earliest claimed: 2015-01-28
- Assignees: Sanyo Electric Co., Ltd.
- Applicants: Sanyo Electric Co., Ltd.
- Inventors: Tatsuya Akira; Hiroshi Minami; Taizou Sunano
- Web page: https://patentgrep.com/patent/US10312516B2

## CPC

- H01M 4/5825: {Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines}
- C01B 33/113: Silicon oxides; Hydrates thereof {(preparing monoxide by reduction of siliceous material C01B33/182)}
- H01M 4/134: Electrodes based on metals, Si or alloys
- H01M 4/136: Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
- H01M 4/1395: of electrodes based on metals, Si or alloys
- H01M 4/1397: of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
- H01M 4/36: Selection of substances as active materials, active masses, active liquids
- H01M 4/364: {as mixtures}
- H01M 4/366: {as layered products}
- H01M 4/38: of elements or alloys
- H01M 4/58: of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- H01M 2004/027: {Negative 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
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A negative-electrode active material for a non-aqueous electrolyte secondary battery containing a silicon material, wherein the negative-electrode active material can constitute a non-aqueous electrolyte secondary battery having high charge capacity, high initial charge/discharge efficiency, and good cycle characteristics. A negative-electrode active material particle according to an embodiment includes a lithium silicate phase represented by Li2zSiO(2+z) {0<z<2} and particles dispersed in the lithium silicate phase. Each of the particles includes a silicon core particle and a surface layer formed of an iron alloy containing Si (FeSi alloy). In an XRD pattern of the negative-electrode active material particle obtained by XRD measurement, a diffraction peak of the FeSi alloy at 2θ=approximately 45 degrees has a half-width of 0.40 degrees or more, and a diffraction peak of a Si (111) plane at 2θ=approximately 28 degrees has a half-width of 0.40 degrees or more.

## Claims

### Claim 1

A negative-electrode active material for a non-aqueous electrolyte secondary battery, comprising:
a lithium silicate phase represented by Li2zSiO(2+z) {0<z<2}; and
particles dispersed in the lithium silicate phase, the particles containing a silicon (Si) core particle and a surface layer formed of an iron alloy containing Si (FeSi alloy),
wherein in an XRD pattern obtained by XRD measurement, a diffraction peak of the FeSi alloy at 2θ=approximately 45 degrees has a half-width of 0.40 degrees or more, and a diffraction peak of a Si (111) plane at 2θ=approximately 28 degrees has a half-width of 0.40 degrees or more.

### Claim 2 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein a diffraction peak of a (111) plane of a lithium silicate in the XRD pattern has a half-width of 0.05 degrees or more.

### Claim 3 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 wherein the metal particles are composed mainly of Fe.

### Claim 4 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the metal or alloy constituting the metal particles forms an alloy with at least one of Si and a lithium silicate.

### Claim 5 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the metal particles constitute 0.01% to 20% by mass of a total mass of a base particle composed of the lithium silicate phase, the silicon particles, and the metal particles.

### Claim 6 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein no SiO2 peak is observed at 2θ=25 degrees in an XRD pattern obtained by XRD measurement.

### Claim 7 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the metal particles have an average particle size of 100 nm or less.

### Claim 8 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the silicon particles have an average particle size of 200 nm or less before initial charging.

### Claim 9 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium silicate phase, the silicon particles, and the metal particles constitute a base particle, and the base particle is covered with an electrically conductive layer.

### Claim 10 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium silicate phase is composed mainly of Li2SiO3.

### Claim 11 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium silicate phase is composed mainly of Li2Si2O5.

### Claim 12 (depends on 1)

The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the negative-electrode active material for a non-aqueous electrolyte secondary battery after charging and discharging contains no Li4SiO4.

### Claim 13 (depends on 1)

A non-aqueous electrolyte secondary battery comprising: a negative electrode containing the negative-electrode active material according to claim 1;
a positive electrode; and
a non-aqueous electrolyte.