# US 2021/0344005 A1 · Core-shell structured nanoparticles for lithium-sulfur cells

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- Number: US 2021/0344005 A1
- Document ID: US20210344005A1
- Status: Published application
- Kind: A1
- Application number: 17/369,241
- Filed: 2021-07-07
- Published: 2021-11-04
- Earliest claimed: 2012-11-07
- Assignees: The Regents of the University of California
- Applicants: The Regents of the University of California
- Inventors: Elton J. Cairns
- Web page: https://patentgrep.com/patent/US20210344005A1

## CPC

- H01M 4/366: {as layered products}
- C23C 16/4417: {Methods specially adapted for coating powder}
- H01B 1/122: {Ionic conductors}
- H01M 4/0402: {Methods of deposition of the material}
- H01M 4/0428: {Chemical vapour deposition}
- H01M 4/0471: {involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis}
- H01M 4/131: Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 4/133: Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/136: Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
- H01M 4/137: Electrodes based on electro-active polymers
- H01M 4/1397: of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
- 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 4/5815: {Sulfides}
- 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
- H01M 10/0569: characterised by the solvents
- H01M 10/052: Li-accumulators
- H01M 2004/028: {Positive electrodes}
- H01M 2300/0028: characterised by the solvent
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Described is a method of synthesizing a plurality of core-shell nanoparticles. The method includes forming shells around a plurality of lithium sulfide nanoparticles, wherein the shells conduct electrons and lithium ions.

## Claims

### Claim 1

A method of synthesizing a plurality of core-shell nanoparticles comprising:
providing a plurality of lithium sulfide nanoparticles; and
forming shells around the plurality of lithium sulfide nanoparticles, wherein the shells conduct electrons and lithium ions.

### Claim 2 (depends on 1)

The method of claim 1, further comprising synthesizing the plurality of lithium sulfide nanoparticles, the synthesizing comprising:
dissolving or suspending a plurality of sulfur particles in an organic solvent to form a solution or suspension;
adding a lithium reducing agent to the solution to react with the plurality of sulfur particles and form precipitates comprising the plurality of lithium sulfide nanoparticles; and
separating the plurality of lithium sulfide nanoparticles from the solution.

### Claim 3 (depends on 1)

The method of claim 1, wherein the shells comprise carbon shells and forming the shells around the plurality of lithium sulfide nanoparticles comprises:
performing chemical vapor deposition (CVD) of carbon onto the plurality of lithium sulfide nanoparticles based on heating the plurality of lithium sulfide nanoparticles in the presence of an oxygen free organic vapor.

### Claim 4 (depends on 3)

The method of claim 3, wherein the organic vapor comprises one of methane, ethylene or acetylene.

### Claim 5 (depends on 1)

The method of claim 1, wherein forming the shells around the plurality of lithium sulfide nanoparticles comprises:
adding the plurality of lithium sulfide nanoparticles to a solution comprising a polar organic solvent and a polymer; and
evaporating the polar organic solvent, leaving behind a plurality of coated lithium sulfide nanoparticles having polymer shells formed thereon.

### Claim 6 (depends on 5)

The method of claim 5, wherein the polar organic solvent comprises toluene, the polymer comprises polyaniline, and the shells comprise polyaniline shells.

### Claim 7 (depends on 5)

The method of claim 5, further comprising:
heating the plurality of core-shell nanoparticles to convert the polymer shells into carbon shells.

### Claim 8 (depends on 1)

The method of claim 1, wherein the shells comprise titanium disulfide shells and forming the shells around the plurality of lithium sulfide nanoparticles comprises reacting titanium tetrachloride onto the plurality of lithium sulfide nanoparticles.

### Claim 9 (depends on 1)

The method of claim 1, further comprising:
creating a mixture comprising the plurality of core-shell nanoparticles, an organic solvent and a polymer binder; and
coating an electrical conductor with the mixture to form a positive electrode.

### Claim 10 (depends on 9)

The method of claim 9, further comprising:
providing a negative electrode;
forming a cell of a lithium sulfur battery that comprises the positive electrode, the negative electrode and an electrolyte separating the positive electrode and the negative electrode, wherein the electrolyte comprises a lithium salt dissolved in an ionic liquid and a porous separator, the ionic liquid being absorbed into the porous separator; and
hermetically sealing the cell.

### Claim 11 (depends on 1)

The method of claim 1, wherein the shells comprise carbon.

### Claim 12 (depends on 1)

The method of claim 1, wherein the shells comprise polyaniline.