Negative electrode active material for non-aqueous electrolyte secondary battery, non-aqueous electrolyte secondary battery, and method for producing negative electrode material for non-aqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-11316152-B2
Application number	US-201816634357-A
Country	US
Kind code	B2
Filing date	Jul 9, 2018
Priority date	Aug 3, 2017
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

A negative electrode active material for a non-aqueous electrolyte secondary battery, containing a negative electrode active material particle, wherein the negative electrode active material particle includes a silicon compound particle containing a silicon compound (SiOx: 0.5≤x≤1.6), the silicon compound particle contains a Li compound, at least a part of the silicon compound particle is coated with a carbon material, and an O-component fragment and a CH-component fragment are detected from the negative electrode active material particle in a measurement by TOF-SIMS, and a ratio of a peak intensity A of the O-component fragment to a peak intensity B of the CH-component fragment is 0.5≤A/B≤100. This provides a negative electrode active material for a non-aqueous electrolyte secondary battery capable of increasing battery capacity and improving the cycle characteristics and battery initial efficiency.

First claim

The invention claimed is:

1. A negative electrode active material for a non-aqueous electrolyte secondary battery, containing a negative electrode active material particle, wherein
the negative electrode active material particle comprises a silicon compound particle containing a silicon compound, SiO x , where 0.5≤x≤1.6,
the silicon compound particle at least partially contains at least one selected from the group consisting of Li 4 SiO 4 , Li 2 SiO 3 , and Li 2 Si 2 O 5 ,
at least a part of the silicon compound particle is coated with a carbon material,
a coating amount of the carbon material is 0.5 mass % or more and 15 mass % or less relative to a total of the silicon compound particle and the carbon material, and
an O-component fragment and a CH-component fragment are detected from the negative electrode active material particle in a measurement by Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), and a ratio of a peak intensity A of the O-component fragment to a peak intensity B of the CH-component fragment is 0.5≤A/B≤100.

2. The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the negative electrode active material particle has a volume resistivity of 0.01 Ω·cm or more and less than 100 Ω·cm which is measured by a four-point probe method in accordance with JIS K 7194 under a load of 38.2 MPa.

3. The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the silicon compound particle has a diffraction peak attributable to a Si(111) crystal face obtained from an X-ray diffraction, a half value width (2θ) of the diffraction peak is 1.2° or more, and a crystallite size corresponding to the crystal face is 7.5 nm or less.

4. The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 2 , wherein the silicon compound particle has a diffraction peak attributable to a Si(111) crystal face obtained from an X-ray diffraction, a half value width (2θ) of the diffraction peak is 1.2° or more, and a crystallite size corresponding to the crystal face is 7.5 nm or less.

5. The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the silicon compound particle has a median diameter of 0.5 μm or more and 20 μm or less.

6. The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 2 , wherein the silicon compound particle has a median diameter of 0.5 μm or more and 20 μm or less.

7. The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 3 , wherein the silicon compound particle has a median diameter of 0.5 μm or more and 20 μm or less.

8. The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 4 , wherein the silicon compound particle has a median diameter of 0.5 μm or more and 20 μm or less.

9. A non-aqueous electrolyte secondary battery comprising the negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 .

10. A method for producing a negative electrode material for a non-aqueous electrolyte secondary battery containing a negative electrode active material particle comprising a silicon compound particle, the method comprising the steps of:
fabricating the silicon compound particle containing a silicon compound, SiO x , where 0.5≤x≤1.6;
coating at least a part of the silicon compound particle with a carbon material to obtain a coated silicon compound particle, a coating amount of the carbon material being 0.5 mass % or more and 15 mass % or less relative to a total of the silicon compound particle and the carbon material;
inserting Li into the silicon compound particle to modify the silicon compound particle in a manner such that the silicon compound particle at least partially contains at least one selected from the group consisting of Li 4 SiO 4 , Li 2 SiO 3 , and Li 2 Si 2 O 5 ; and
cleaning the coated silicon compound particle after modification; and
selecting the negative electrode active material particle, wherein an O-component fragment and a CH-component fragment are detected from the negative electrode active material particle after cleaning, in a measurement by TOF-SIMS, and a ratio of a peak intensity A of the O-component fragment to a peak intensity B of the CH-component fragment is 0.5≤A/B≤100, and
wherein the negative electrode material for the non-aqueous electrolyte secondary battery is produced using the negative electrode active material particle which has been selected.

11. A method for producing a negative electrode material for a non-aqueous electrolyte secondary battery containing a negative electrode active material particle comprising a silicon compound particle, the method comprising:
fabricating the silicon compound particle containing a silicon compound, SiO x , where 0.5≤x≤1.6;
coating at least a part of the silicon compound particle with a carbon material to obtain a coated silicon compound particle, a coating amount of the carbon material being 0.5 mass % or more and 15 mass % or less relative to a total of the silicon compound particle and the carbon material;
inserting Li into the silicon compound particle to modify the silicon compound particle in a manner such that the silicon compound particle at least partially contains at least one selected from the group consisting of Li 4 SiO 4 , Li 2 SiO 3 , and Li 2 Si 2 O 5 ;
cleaning the coated silicon compound particle after modification; and
fabricating the negative electrode active material particle by performing on the coated silicon compound particle after cleaning, a surface modification to adjust an intensity of an O-component fragment detected in a measurement by TOF-SIMS such that the O-component fragment and a CH-component fragment are detected in a measurement by TOF-SIMS, and a ratio of a peak intensity A of the O-component fragment to a peak intensity B of the CH-component fragment is 0.5≤A/B≤100;
wherein the negative electrode material for the non-aqueous electrolyte secondary battery is produced using the negative electrode active material particle which has been fabricated.

12. The method according to claim 11 , wherein
the surface modification to adjust the intensity of the O-component fragment detected in the measurement by TOF-SIMS includes:
decreasing the ratio of the peak intensity A of the O-component fragment to the peak intensity B of the CH-component fragment by increasing a cleaning time of the coated silicon compound particle after modification with alcohol, alkaline water, weak acid, or pure water; or
increasing the ratio of the peak intensity A of the O-component fragment to the peak intensity B of the CH-component fragment by heating the coated silicon compound particle after cleaning under a CO 2 atmosphere.

Assignees

• Shinetsu Chemical Co

Inventors

• Takahashi Kohta
• Hirose Takakazu
• Matsuno Takumi

Classifications

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/625

  Carbon or graphite · CPC title