# US 10,873,075 B2 · Composite anode material including particles having buffered silicon-containing core and graphene-containing shell

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- Number: US 10,873,075 B2
- Document ID: US10873075B2
- Status: Granted
- Kind: B2
- Application number: 15/694,144
- Filed: 2017-09-01
- Published: 2019-03-07
- Granted: 2020-12-22
- Earliest claimed: 2017-09-01
- Assignees: Nanograf Corporation
- 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/US10873075B2

## 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 crumpled sheets of graphene, crumpled sheets of graphene oxide, crumpled sheets of at least partially reduced graphene oxide, or combinations thereof; and
active material particles disposed within the capsules, each active material particle comprising:
a core comprising silicon, silicon oxide, or a combination thereof; and
a buffer layer at least partially surrounding the core and comprising a polymeric material or a pyrolyzed polymeric material,
wherein each capsule defines an interior void space configured to accommodate volumetric expansion of the active material particles during charging of the composite anode material, and
wherein the composite anode material provides a buffer matrix in which a combination of the buffer layer and the interior void space within each capsule reduce mechanical degradation of the core during lithium ion intercalation and deintercalation.

### 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 composite anode material has an average particle size that ranges from about 0.5 μm to about 10 μm.

### Claim 5 (depends on 1)

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

### Claim 6 (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 7 (depends on 1)

The composite anode material of claim 1, wherein the buffer layers comprise the polymeric material and the polymeric material is chemically cross-linked.

### Claim 8 (depends on 7)

The composite anode material of claim 7, wherein the polymeric material is chemically cross-linked by boric acid, citric acid, glutaraldehyde (GA), fumaric acid, or a combination thereof.

### Claim 9 (depends on 7)

The composite anode material of claim 7, wherein the polymeric material comprises polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl formal (PVF), polyacrylonitrile (PAN), or a combination thereof.

### Claim 10

An electrode, comprising:
capsules comprising crumpled sheets of graphene, crumpled sheets of graphene oxide, crumpled sheets of at least partially reduced graphene oxide, or combinations 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 combinations thereof; and
a buffer layer surrounding the core and comprising a polymeric material or a pyrolyzed polymeric material; and
a binder,
wherein each capsule defines an interior void space configured to accommodate volumetric expansion of the active material particles during charging of the composite anode material, and
wherein the composite anode material provides a buffer matrix in which a combination of the buffer layer and the interior void space within each capsule reduce mechanical degradation of the core during lithium ion intercalation and deintercalation.

### Claim 11 (depends on 10)

The electrode of claim 10, wherein the cores have an average particle size ranging from about 50 nm to about 400 nm.

### Claim 12 (depends on 10)

The electrode of claim 10, wherein the binder comprises polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), poly(acrylic) acid, polyethylenetetrafluoroethylene (ETFE), a polyamide, a polyimide, polyethylene, styrene-butadiene rubber, cellulose, polyacrylate rubber, or a mixture thereof.

### Claim 13 (depends on 10)

The electrode of claim 10, 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 14 (depends on 10)

The electrode of claim 10, wherein the buffer layers comprise the pyrolyzed polymeric material.

### Claim 15 (depends on 10)

The electrode of claim 10, wherein the polymeric material comprises polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl formal (PVF), polyacrylonitrile (PAN), or a combination thereof.

### Claim 16 (depends on 10)

The electrode of claim 10, wherein the buffer layers comprise the polymeric material, and the polymeric material is chemically cross-linked.

### Claim 17 (depends on 16)

The electrode of claim 16, wherein the polymeric material is chemically cross-linked by boric acid, citric acid, glutaraldehyde (GA), fumaric acid, or a combination thereof.

### Claim 18 (depends on 1)

A method of fabricating an anode 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 19 (depends on 18)

The method of claim 18, wherein the binder comprises_polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), poly(acrylic) acid, polyethylenetetrafluoroethylene (ETFE), polyamides, and polyimides, polyethylene, styrene-butadiene rubber, cellulose, polyacrylate rubber, or a mixture thereof.

### Claim 20 (depends on 18)

The method of claim 18, 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.