# US 2019/0074508 A1 · Composite anode material including encapsulated buffered active material particles

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- Number: US 2019/0074508 A1
- Document ID: US20190074508A1
- Status: Published application
- Kind: A1
- Application number: 15/694,144
- Filed: 2017-09-01
- Published: 2019-03-07
- Earliest claimed: 2017-09-01
- Assignees: Sinode Systems, Inc.
- Applicants: Sinode Systems, Inc.
- Inventors: Seonbaek HA; Cary M. HAYNER; Joshua J. LAU; James MCKINNEY; Francis WANG; Woo Hyun CHAE
- Web page: https://patentgrep.com/patent/US20190074508A1

## CPC

- H01M 4/366: {as layered products}
- H01M 4/0471: {involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis}
- H01M 4/13: Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M 4/133: Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/134: Electrodes based on metals, Si or alloys
- H01M 4/139: Processes of manufacture
- H01M 4/1395: of electrodes based on metals, Si or alloys
- H01M 4/386: {Silicon or alloys based on silicon}
- H01M 4/483: {for non-aqueous cells (H01M4/485 takes precedence)}
- H01M 4/62: Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M 4/621: {Binders}
- H01M 4/625: {Carbon or graphite}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane
- 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 composite anode material including an active material including a core of silicon, silicon oxide, or combination thereof encased within a buffer layer including a polymeric material, and a shell encapsulating the active material. The shell may include graphene, graphene oxide, partially reduced graphene oxide, or combinations thereof.

## Claims

### Claim 1

A composite anode material, comprising:
capsules comprising graphene, graphene oxide, at least partially reduced graphene oxide, or a combination thereof; and
active material particles disposed within the capsules, each active material particle comprising:
a core comprising silicon, silicon oxide, or combination thereof; and
a buffer layer surrounding the core and comprising a polymeric material.

### Claim 2 (depends on 1)

The composite anode material of claim 1, wherein the cores have an average particle size ranging from about 50 nm to about 400 nm.

### Claim 3 (depends on 1)

The composite anode material of claim 1, wherein:
the capsules comprise a single active material particle or a plurality of the active material particles; and
the active material particles each comprise a single core disposed in the buffer layer or a plurality of the cores disposed in the buffer layer.

### Claim 4 (depends on 1)

The composite anode material of claim 1, wherein the buffer layers are chemically cross-linked.

### Claim 5 (depends on 1)

The composite anode material of claim 1, wherein the buffer layers are chemically cross-linked by a material comprises boric acid, citric acid, glutaraldehyde (GA), fumaric acid, or a combination thereof.

### Claim 6 (depends on 1)

The composite anode material of claim 1, wherein the buffer layers are pyrolyzed.

### Claim 7 (depends on 1)

The composite anode material of claim 1, wherein the polymeric material comprises polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl formal (PVF), polyacrylonitrile (PAN), or a combination thereof.

### Claim 8 (depends on 1)

The composite anode material of claim 1, wherein each of the capsules comprises an interior void space in which at least one active material particle is disposed.

### Claim 9 (depends on 1)

The electrode of claim 1, wherein the composite anode material has an average particle size that ranges from about 0.5 μm to about 10 μm.

### Claim 10 (depends on 1)

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

### Claim 11

An electrode, comprising:
capsules that comprise graphene, graphene oxide, at least partially reduced graphene oxide, or a combination thereof;
at least one active material particle disposed within each of the capsules, each active material particle comprising:
a core comprising silicon, silicon oxide or combination thereof; and
a buffer layer surrounding the core and comprising a polymeric material; and
a binder.

### Claim 12 (depends on 11)

The electrode of claim 11, wherein the cores have an average particle size ranging from about 50 nm to about 400 nm.

### Claim 13 (depends on 11)

The electrode of claim 11, wherein the buffer layers are chemically cross-linked.

### Claim 14 (depends on 11)

The electrode of claim 11, wherein the buffer layers are chemically cross-linked by a chemical comprises boric acid, citric acid, glutaraldehyde (GA), fumaric acid, or a combination thereof.

### Claim 15 (depends on 11)

The electrode of claim 11, wherein the buffer layers are pyrolyzed.

### Claim 16 (depends on 11)

The electrode of claim 11, wherein the polymer comprises polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl formal (PVF), polyacrylonitrile (PAN), or a combination thereof.

### Claim 17 (depends on 11)

The electrode of claim 11, 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.

### Claim 18 (depends on 11)

The electrode of claim 11, wherein 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 measured by dividing the mass of a dried electrode by its volume and the theoretical density is the density of the composite anode material that is 100 percent dense.

### Claim 19 (depends on 1)

A method of fabricating an electrode, the method comprising:
mixing the composite 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 electrode.

### Claim 20 (depends on 19)

The method of claim 19, wherein each of the capsules comprises an interior void space in which at least one active material particle is disposed.

### Claim 21 (depends on 19)

The method of claim 19, 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 mixtures thereof.

### Claim 22 (depends on 19)

The method of claim 19, wherein 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 23

A method of forming composite anode material particles, the method comprising:
combining core particles comprising silicon, silicon oxide, or a combination thereof, with a first liquid and a polymeric material, to form a first mixture;
heating the first mixture at a first temperature to form active material particles comprising the core particles coated with the polymeric material;
combining the active material particles with graphene, graphene oxide, partially reduced graphene oxide or a combination thereof and a second liquid, to form a second mixture; and
heating the second mixture at a second temperature greater than the first temperature, to form composite anode material particles.

### Claim 24 (depends on 23)

The method of claim 23, wherein the heating the second mixture including spray drying the second mixture at the second temperature in an inert atmosphere.

### Claim 25 (depends on 23)

The method of claim 23, wherein the first temperature is from about 25° C. to about 70° C.

### Claim 26 (depends on 25)

The method of claim 25, wherein the second temperature is from about 150° C. to about 220° C.

### Claim 27 (depends on 23)

The method of claim 23, wherein the first mixture further comprises a cross-linking agent comprising boric acid, citric acid, glutaraldehyde (GA), fumaric acid, or a combination thereof.

### Claim 28 (depends on 23)

The method of claim 23, wherein the first liquid and the second liquid are selected from deionized water, isopropanol alcohol (C3H8O), isopropyl alcohol (C3H8O), ethanol (C2H8O), acetone (C3H8O), or combinations thereof.

### Claim 29 (depends on 23)

The method of claim 23, further comprising pyrolyzing the composite anode material particles at a third temperature greater than the second temperature.

### Claim 30 (depends on 29)

The method of claim 29, wherein the third temperature ranges from about 600° C. to about 800° C.

### Claim 31 (depends on 23)

The method of claim 23, wherein the polymeric material comprises polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl formal (PVF), polyacrylonitrile (PAN), or a combination thereof.