# US 10,374,215 B2 · Centrifugation-assisted preparation of additive-free carbon-decorated magnetite electrodes

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- Number: US 10,374,215 B2
- Document ID: US10374215B2
- Status: Granted
- Kind: B2
- Application number: 14/884,939
- Filed: 2015-10-16
- Published: 2016-04-21
- Granted: 2019-08-06
- Earliest claimed: 2014-10-17
- Assignees: Wayne State University
- Applicants: Wayne State University
- Inventors: Da Deng; Jian Zhu; K. Y. Simon Ng
- Web page: https://patentgrep.com/patent/US10374215B2

## CPC

- H01M 4/0402: {Methods of deposition of the material}
- C01B 32/15: Nano-sized carbon materials
- C01G 49/06: Ferric oxide [Fe2O3]
- C01G 49/08: Ferroso-ferric oxide [Fe3O4]
- H01M 4/131: Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 4/1391: of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 4/362: {Composites}
- H01M 4/523: {for non-aqueous cells (H01M4/525 takes precedence)}
- H01M 4/625: {Carbon or graphite}
- C01P 2002/60: Compounds characterised by their crystallite size
- C01P 2002/72: by d-values or two theta-values, e.g. as X-ray diagram
- C01P 2002/85: by XPS, EDX or EDAX data
- C01P 2002/88: by thermal analysis data, e.g. TGA, DTA, DSC
- C01P 2004/03: obtained by SEM
- C01P 2004/04: obtained by TEM, STEM, STM or AFM
- C01P 2004/30: extending in three dimensions
- C01P 2004/45: Aggregated particles or particles with an intergrown morphology
- C01P 2004/62: Submicrometer sized, i.e. from 0.1-1 micrometer
- C01P 2004/80: Particles consisting of a mixture of two or more inorganic phases
- C01P 2006/40: Electric properties
- H01M 4/661: {Metal or alloys, e.g. alloy coatings (H01M4/669 take precedence)}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- Y02E 60/10: Energy storage using batteries
- 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}
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Iron nanoparticles that are useful for constructing electrodes for lithium ion batteries and a method of making said particles is disclosed herein. The nanoparticles may include magnetite. The electrode may be constructed by centrifuging the nanoparticles to a current collector, such as a disc of copper, without the use of an extrinsic binder. The solvothermal method of making nanoparticles decreases the time of the procedure from about 24 hours to about 75 minutes. The method of making electrode decreases the complexity and number of steps compared to the conventional procedure to prepare an electrode, and eliminates the use of additives (binder and current enhancer) and toxic NMP solvents in the electrode preparation process.

## Claims

### Claim 1

An electrode for a lithium ion battery, the electrode comprising:
a metal current collector having a first face and a second face opposite the first face; and
a plurality of nanoparticles having a particulate form and comprising a composite of Fe3O4 and carbon, the nanoparticles being porous and having a substantially elliptical structure, the nanoparticles being bound directly to the first face of the metal current collector without a polymeric adhesive, the nanoparticles having a carbon content by weight of less than 4%,
wherein the electrode has a specific capacity of at least about 750 mAh/g after about 240 charge-discharge cycles.

### Claim 2 (depends on 1)

The electrode according to claim 1 wherein the nanoparticle has carbon dispersed through the nanoparticle.

### Claim 3 (depends on 1)

The electrode according to claim 1, having a specific capacity of at least about 700 mAh/g when exposed to a current of about 1500 mA/g.

### Claim 4 (depends on 1)

The electrode of claim 1, wherein the nanoparticle is about 300 to about 600 nanometers in length, and about 200 to about 400 nanometers in diameter.

### Claim 5 (depends on 1)

The electrode of claim 1, wherein the carbon content by weight of the nanoparticle is less than 1%.

### Claim 6 (depends on 1)

The electrode of claim 1, wherein α-Fe2O3 is not detected in the nanoparticle by x-ray diffraction.

### Claim 7 (depends on 1)

The electrode of claim 1, wherein a length of the nanoparticle is greater than a diameter in a direction normal the length.