# US 10,312,500 B2 · Formation of slurry for high loading sulfur cathodes

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- Number: US 10,312,500 B2
- Document ID: US10312500B2
- Status: Granted
- Kind: B2
- Application number: 14/988,917
- Filed: 2016-01-06
- Published: 2017-07-06
- Granted: 2019-06-04
- Earliest claimed: 2016-01-06
- Assignees: Toyota Motor Engineering & Manufacturing North America, Inc.
- Applicants: Toyota Motor Engineering & Manufacturing North America, Inc.
- Inventors: Naoki Osada; Claudiu B. Bucur; John Muldoon
- Web page: https://patentgrep.com/patent/US10312500B2

## CPC

- H01M 4/0435: {Rolling or calendering}
- H01M 4/0404: {by coating on electrode collectors}
- H01M 4/139: Processes of manufacture
- H01M 4/366: {as layered products}
- H01M 4/581: {Chalcogenides or intercalation compounds thereof}
- H01M 4/622: {being polymers}
- H01M 4/625: {Carbon or graphite}
- H01M 4/661: {Metal or alloys, e.g. alloy coatings (H01M4/669 take precedence)}
- H01M 10/052: Li-accumulators
- H01M 10/0568: characterised by the solutes
- H01M 10/0569: characterised by the solvents
- 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 high density slurry comprising encapsulated sulfur particles, carbon nanofibers and activated carbon black suitable for use in forming the active material of an electrode. A method for forming the high density sulfur slurry is also provided. A cathode containing the particles and a battery constructed with the cathode as well as methods for their formation are also provided.

## Claims

### Claim 1

A slurry, comprising:
encapsulated chalcogen particles, comprising a chalcogen core and an encapsulate coating disposed on the chalcogen core surface consisting of at least one polymer having both hydrophobic regions and hydrophilic regions;
carbon nanofibers;
carbon black;
carboxymethyl cellulose;
styrene butadiene rubber; and
water;
wherein
a sulfur content of the encapsulated chalcogen particles is greater than 90 wt % relative to the total dry weight of the encapsulated chalcogen particles,
a content of sulfur is greater than 85 wt % relative to a total dry weight of the slurry; and
a ratio of carbon nanofibers to carbon black is 3:1.

### Claim 2 (depends on 1)

The slurry of claim 1, wherein a total content of the carbon nanofiber and carbon black is less than 10 wt % relative to the total dry weight of the slurry.

### Claim 3 (depends on 1)

The slurry of claim 1, wherein a total content of the carboxymethyl cellulose and styrene butadiene rubber is less than 5 wt % relative to the total dry weight of the slurry.

### Claim 4 (depends on 1)

The slurry of claim 1, wherein a ratio of carboxymethyl cellulose to styrene butadiene rubber is 3:1.

### Claim 5 (depends on 1)

The slurry of claim 1, wherein water is present in an amount equal to 0.25-1.25 times the total dry weight of the slurry.

### Claim 6 (depends on 1)

The slurry of claim 1, wherein the chalcogen core further comprises at least one of selenium and tellurium.

### Claim 7 (depends on 1)

The slurry of claim 1, wherein the polymer coating consists of at least one polymer selected from the group consisting of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate, polyvinylpyrrolidone, polyaniline, poly(ethylene oxide), carboxymethyl cellulose, sodium carboxymethyl cellulose, polymethacrylic acid, poly(2-acrylamido-2-methyl-1-propanesulfonic acid), branched polyethylenimine, and poly(diallyl dimethylammonium chloride).

### Claim 8 (depends on 6)

The slurry of claim 6, wherein a selenium content or a tellurium content of the encapsulated chalcogen particles is less than 50 wt % relative to a total weight of the encapsulated chalcogen particles.

### Claim 9 (depends on 6)

The slurry of claim 6, wherein the encapsulated chalcogen core further comprises carbon black particles, functionalized carbon black particles or both which are homogeneously dispersed in the chalcogen core.

### Claim 10 (depends on 1)

A method for forming the slurry of claim 1, comprising:
forming a powder mixture comprising 90 wt % of the encapsulated chalcogen particles relative to the total dry weight of the slurry and 8 wt % of carbon nanofibers and carbon black together relative to the total dry weight of the slurry;
grinding the powder mixture to form a powder of carbon and active material;
adding a weight corresponding to 2 wt % of carboxymethyl cellulose and styrene butadiene rubber together relative to the total dry weight of the slurry to the powder of carbon and active material to form a thick slurry;
adding water to the thick slurry;
mixing the thick slurry to form the slurry.

### Claim 11 (depends on 10)

The method of claim 10, wherein water is added in an amount of 0.4-1.2 mL per g of the thick slurry.

### Claim 12 (depends on 10)

The method of claim 10, wherein the mixing is performed by planetary centrifugation for up to 15 minutes at a speed of greater than 1000 rpm.

### Claim 13 (depends on 10)

The method of claim 10, further comprising ball milling the fine powder of carbon and active material for up to 2 hours at a speed of less than 200 rpm.

### Claim 14 (depends on 1)

An electrode, comprising:
the dried slurry of claim 1 as active material; and
a current collector;
wherein the dried slurry is on a surface of the current collector.

### Claim 15 (depends on 14)

The electrode of claim 14, wherein a sulfur weight per current collector area is in the range of 3-8 mg/cm2.

### Claim 16 (depends on 14)

The electrode of claim 14, wherein the current collector comprises aluminum.

### Claim 17 (depends on 14)

A method for forming the electrode of claim 14, comprising:
pouring the slurry onto the current collector
forming a wet gap of less than 200 μm to obtain a green electrode;
drying the green electrode; and
calendering the dried green electrode to form the electrode.

### Claim 18 (depends on 17)

The method of claim 17, wherein the drying is performed in an oven at a temperature of up to 100° C. for up to 12 hours.

### Claim 19 (depends on 17)

The method of claim 17, wherein the dried green electrode is calendered such that the electrode has less than 50% of the thickness of the dried green electrode.

### Claim 20 (depends on 14)

A battery, comprising:
the electrode of claim 14 as a cathode;
an anode; and
an electrolyte in a solvent.

### Claim 21 (depends on 20)

The battery of claim 20, wherein the anode comprises a metal selected from the group consisting of an alkali metal and an alkaline earth metal.

### Claim 22 (depends on 20)

The battery of claim 20, wherein the anode is lithium and the electrolyte comprises LiTFSI and LiNO3 in a molar ratio of 5:1.

### Claim 23 (depends on 22)

The battery of claim 22, wherein the solvent comprises glyme and dioxolane in a weight ratio of 1:1.

### Claim 24 (depends on 20)

The battery of claim 20, wherein the anode is lithium and the anode is pretreated with a lithium polysulfide.

### Claim 25 (depends on 20)

A vehicle comprising the battery of claim 20.