# US 2019/0044128 A1 · Composite anode material including surface-stabilized active material particles and methods of making same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2019/0044128 A1
- Document ID: US20190044128A1
- Status: Published application
- Kind: A1
- Application number: 15/667,882
- Filed: 2017-08-03
- Published: 2019-02-07
- Earliest claimed: 2017-08-03
- Assignees: Sinode Systems, Inc.
- Applicants: Sinode Systems, Inc.
- Inventors: James MCKINNEY; Cary M. HAYNER; Joshua J. LAU; Seonbaek HA; Francis WANG
- Web page: https://patentgrep.com/patent/US20190044128A1

## CPC

- H01M 4/133: Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- 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 4/366: {as layered products}
- H01M 4/386: {Silicon or alloys based on silicon}
- H01M 4/483: {for non-aqueous cells (H01M4/485 takes precedence)}
- 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 4/587: for inserting or intercalating light metals
- H01M 4/622: {being polymers}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- C01B 32/198: Graphene oxide
- Y02E 60/10: Energy storage using batteries
- Y02P 20/133: Renewable energy sources, e.g. sunlight
- 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
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Composite anode materials and methods of making same, the anode materials including capsules including graphene, reduced graphene oxide, graphene oxide, or a combination thereof, and particles of an active material disposed inside of the capsules. The particles may each include a core and a buffer layer surrounding the core. The core may include crystalline silicon, and the buffer layer may include a silicon oxide, a lithium silicate, carbon, or a combination thereof.

## Claims

### Claim 1

A composite anode material comprising:
capsules comprising graphene, reduced graphene oxide, graphene oxide, or a combination thereof; and
active material particles disposed inside of the capsules, each particle comprising:
a core; and
a buffer layer surrounding the core,
wherein the buffer layer and the core comprise different materials.

### Claim 2 (depends on 1)

The anode material of claim 1, wherein the core comprises crystalline silicon.

### Claim 3 (depends on 2)

The anode material of claim 2, wherein the buffer layer comprises Si2Ox, where 0<x<0.8.

### Claim 4 (depends on 2)

The anode material of claim 2, wherein the buffer layer comprises silicon oxide, a lithium silicate, carbon, or a combination thereof.

### Claim 5 (depends on 2)

The anode material of claim 2, wherein the buffer layer comprises Li2Si2O5, Li2SiO3, Li4SiO4, or a combination thereof.

### Claim 6 (depends on 1)

The anode material of claim 1, wherein:
the capsules have an average particle size that ranges from about 0.5 μm to about 10 μm; and
the particles have an average particle size that ranges from about 30 nm to about 500 nm.

### Claim 7 (depends on 1)

The anode material of claim 1, wherein the buffer layers have an average thickness that ranges from about 1 nm to about 50 nm.

### Claim 8 (depends on 1)

The anode material of claim 1, wherein the buffer layers have an average thickness that ranges from about 5 nm to about 10 nm.

### Claim 9

An anode, comprising:
capsules comprising graphene, reduced graphene oxide, graphene oxide, or a combination thereof;
active material particles disposed inside of the capsules, each particle comprising:
a core; and
a buffer layer surrounding the core,
wherein the buffer layer and the core comprise different materials; and
a binder.

### Claim 10 (depends on 9)

The anode of claim 9, wherein:
the core comprises crystalline silicon; and
the buffer layer comprises Si2Ox, where 0<x<0.8.

### Claim 11 (depends on 9)

The anode of claim 9, wherein:
the core comprises crystalline silicon; and
the buffer layer comprises Li2Si2O5, Li2SiO3, Li4SiO4, or a combination thereof.

### Claim 12 (depends on 9)

The anode of claim 9, wherein:
the core comprises crystalline silicon; and
the buffer layer comprises a combination of a silicon oxide, lithium silicates, and carbon.

### Claim 13 (depends on 9)

The anode of claim 9, wherein:
the binder comprises polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), poly(acrylic) acid, polyethylenetetrafluoroethylene (ETFE), polyamides, and polyimides, polyethylene (UHMW), styrene-butadiene rubber, cellulose, polyacrylate rubber, or a mixture thereof; and
the electrode has an internal porosity that ranges from about 40 percent to about 60 percent, as measured by the equation:
Internal


Porosity


(
%
)
=
1
-
(
measured


density
theoretical


density
)
where the measured density is calculated by dividing the mass of a dried electrode by its volume, and the theoretical density is the density of the electrochemically active material that is 100 percent dense.

### Claim 14 (depends on 1)

A method of fabricating an anode, the method comprising:
mixing the anode material of claim 1 with a solvent and a binder to form a slurry;
coating a substrate with the slurry; and
drying the coated substrate to form the anode.

### Claim 15 (depends on 14)

The method of claim 14, wherein:
the core comprises crystalline silicon;
the coating comprises silicon oxide, a lithium silicate, carbon, or a combination thereof;
the binder comprises polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), poly(acrylic) acid, polyethylenetetrafluoroethylene (ETFE), polyamides, and polyimides, polyethylene (UHMW), styrene-butadiene rubber, cellulose, polyacrylate rubber, or a combination thereof; and
the solvent comprises water, ethanol, isopropyl alcohol, ethylene glycol, ethyl acetate, polar protiac solvents, polar aprotic solvents, N-methyl-2-pyrrolidone, or a combination thereof.

### Claim 16

A method of forming an anode active material, the method comprising:
heating crystalline silicon particles in an inert atmosphere at a first temperature ranging from about 700° C. to about 900° C.;
heating the particles at the first temperature in an oxidizing atmosphere, for a first time period, to form oxidized particles that each comprise a silicon oxide layer surrounding a crystalline silicon core; and
cooling the oxidized particles in an inert atmosphere.

### Claim 17 (depends on 16)

The method of claim 16, wherein:
the first time period ranges from about 10 minutes to about 40 minutes; and
the particles are heated in a tube furnace.

### Claim 18 (depends on 16)

The method of claim 16, further comprising:
mixing the oxidized particles, a lithium salt, and a solvent to form a mixture;
drying the mixture; and
heating the dried mixture at a temperature ranging from about 600° C. to about 700° C. in an inert atmosphere for a second time period, to form active material particles that each comprise a buffer layer comprising a lithium silicate surrounding a crystalline silicon core.

### Claim 19 (depends on 18)

The method of claim 18, wherein:
the lithium salt comprises lithium acetate dehydrate, LiO2, LiS, LiPF6, bis(oxalato)borate (LiBOB), oxalyldifluoroborate (LiODFB, fluoroalkylphosphate (LiFAP), or a combination thereof;
the mixture comprises a weight ratio of the oxidized particles to the lithium salt ranging from about 1:0.5 to about 1:0.75; and
the mixture comprises a solids content ranging from about 5 wt % to about 15 wt %, based on the total weight of the mixture.

### Claim 20 (depends on 18)

The method of claim 18, wherein:
the lithium salt comprises lithium acetate dehydrate; and
the buffer layer further comprises carbon.

### Claim 21 (depends on 18)

The method of claim 18, further comprising using capillary compression to encapsulate the active material particles in capsules comprising graphene, reduced graphene oxide, graphene oxide, or a combination thereof.