NEGATIVE ELECTRODE ACTIVE MATERIAL AND LITHIUM ION SECONDARY BATTERY USING THE SAME

• US 20190051928A1
• Filed: 02/22/2017
• Published: 02/14/2019
• Est. Priority Date: 02/29/2016
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: KAWASAKI, Daisuke, OHTSUKA, Takashi, TAMAI, Suguru, YOSHIDA, Noboru, SUDO, Shinya
• Granted Patent: US 10,644,347 B2
• Time in Patent Office: Days
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0566 Liquid materials
• CPC Class Codes: H01M 10/058 Construction or manufacture
• CPC Class Codes: H01M 10/0585 of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/364 as mixtures
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/583 Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/622 being polymers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A negative electrode active material constituting a lithium ion secondary battery having high energy density and excellent cycle characteristics, and a negative electrode and a lithium ion secondary battery comprising the same are provided. The present invention relates to a negative electrode active material comprising graphite particles and crystalline silicon particles, wherein a median diameter of the crystalline silicon particles is 0.7 μm or less, and a weight ratio of the crystalline silicon particles to the total weight of the graphite particles and the crystalline silicon particles is 1 wt % or more and 25 wt % or less.

Claims

1. A negative electrode active material comprising graphite particles and crystalline silicon particles, wherein

a median diameter of the crystalline silicon particles is 0.7 μ

m or less, and

a weight ratio of the crystalline silicon particles to the total weight of the graphite particles and the crystalline silicon particles is 1 wt % or more and 25 wt % or less.

2. The negative electrode active material according to claim 1, further comprising silicon oxide.

3. The negative electrode active material according to claim 1, wherein X/Y is 2/100 or more and 40/100 or less, in which X is a median diameter of the crystalline silicon particles and Y is a median diameter of the graphite particles.

4. A negative electrode comprising the negative electrode active material according to claim 1.

5. The negative electrode according to claim 4, further comprising a negative electrode binder comprising polyacrylic acid and/or polyimide.

6. The negative electrode according to claim 5, wherein the polyacrylic acid comprises a monomer unit based on an ethylenically unsaturated carboxylic acid and a monomer unit based on an alkali metal salt of an ethylenically unsaturated carboxylic acid and/or a monomer unit based on an aromatic vinyl compound.

7. A lithium ion secondary battery comprising the negative electrode according to claim 4.

8-9. -9. (canceled)