Negative electrode active material, mixed negative electrode active material, negative electrode for nonaqueous electrolyte secondary battery, lithium ion secondary battery, and, production method of negative electrode active material

Patent metadata

Field	Value
Publication number	US-10991971-B2
Application number	US-201615768660-A
Country	US
Kind code	B2
Filing date	Oct 24, 2016
Priority date	Nov 17, 2015
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

The present disclosure relates to a negative electrode active material including: particles of negative electrode active material, wherein the particles of negative electrode active material contain particles of silicon compound containing a silicon compound (SiO x : 0.55≤x≤1.6), and the particles of silicon compound includes at least one or more kinds of Li 2 SiO 3 and Li 4 SiO 4 ; the particles of silicon compound contain nickel; and, a mass of the nickel to a mass of the particles of negative electrode active material is 2 mass ppm or more and 100 mass ppm or less. Thus, when used as the negative electrode active material of a secondary battery, a negative electrode active material capable of improving the initial charge/discharge characteristics and cycle characteristics is provided.

First claim

The invention claimed is:

1. A negative electrode active material comprising:
particles of negative electrode active material,
wherein:
the particles of negative electrode active material contain particles of silicon compound;
the particles of silicon compound contain:
(i) a silicon compound (SiO x :0.5≤x≤1.6);
(ii) at least one or more kinds of Li 2 SiO 3 and Li 4 SiO 4 ;
(iii) nickel, a mass of the nickel to a mass of the particles of negative electrode active material is 2 mass ppm or more and 100 mass ppm or less; and
(iv) aluminum in a form of an aluminum-lithium alloy in at least a part of inside of the particles of silicon compound, a mass of the aluminum to the mass of the particles of negative electrode active material is 5 mass ppm or more and 500 mass ppm or less.

2. The negative electrode active material according to claim 1 ,
wherein the particles of silicon compound further contain chromium; and
a sum total of a mass of the nickel and a mass of the chromium to the mass of the particles of negative electrode active material is 2 mass ppm or more and 100 mass ppm or less.

3. The negative electrode active material according to claim 1 , wherein the particles of silicon compound further contain zirconium, and a mass of the zirconium to the mass of the particles of negative electrode active material is 0.5 mass ppm or more and 500 mass ppm or less.

4. The negative electrode active material according to claim 3 , wherein the mass of the zirconium to the mass of the particles of negative electrode active material is 10 mass ppm or more and 100 mass ppm or less.

5. The negative electrode active material according to claim 1 , wherein the particles of silicon compound have a half value width (2θ) of a diffraction peak derived from a Si(111) crystal plane obtained by X-ray diffractometry of 1.2° or more and a crystallite size corresponding to the crystal plane of 7.5 nm or less.

6. The negative electrode active material according to claim 1 , wherein the particles of silicon compound satisfy a relationship of A>B between a maximum peak intensity value A of Si and Li silicate regions provided in −60 to −95 ppm as a chemical shift value obtained from a 29 Si-MAS-NMR spectrum and a peak intensity value B of a SiO 2 region provided in −96 to −150 ppm as the chemical shift value in the particles of silicon compound.

7. The negative electrode active material according to claim 1 , wherein when a test cell formed of a negative electrode containing a mixture of the negative electrode active material and a carbon-based active material and a counter electrode lithium is prepared, in the test cell, charge/discharge formed of charge during which a current is flowed so as to insert lithium into the negative electrode active material and discharge during which the current is flowed so as to detach the lithium from the negative electrode active material is carried out 30 times, and a graph showing a relationship between a differential value dQ/dV obtained by differentiating a discharge capacity Q by a potential V of the negative electrode based on the counter electrode lithium and the potential V is depicted in each charge/discharge, the potential V of the negative electrode during discharges on or after X times (1≤X≤30) has a peak in the range of from 0.40 V to 0.55 V.

8. The negative electrode active material according to claim 1 , wherein the particles of negative electrode active material have a median diameter of 1.0 μm or more and 15 μm or less.

9. The negative electrode active material according to claim 1 wherein the particles of negative electrode active material contain a carbon material on a superficial part.

10. The negative electrode active material according to claim 9 , wherein an average thickness of the carbon material is 10 nm or more and 5000 nm or less.

11. The negative electrode active material according to claim 1 , wherein the mass of the aluminum to the mass of the particles of negative electrode active material is 5 mass ppm or more and 150 mass ppm or less.

12. A mixed negative electrode active material comprising:
the negative electrode active material according to claim 1 and a carbon-based active material.

13. A negative electrode for nonaqueous electrolyte secondary batteries comprising:
the mixed negative electrode active material according to claim 12 ,
wherein a ratio of a mass of the negative electrode active material relative to a sum total of masses of the negative electrode active material and the carbon-based active material is 6% or more.

14. A negative electrode for nonaqueous electrolyte secondary batteries comprising:
a negative electrode active material layer formed with the mixed negative electrode active material according to claim 12 ; and
a negative electrode current collector,
wherein the negative electrode active material layer is formed on the negative electrode current collector; and
the negative electrode current collector contains carbon and sulfur, and each content thereof is 100 mass ppm or less.

15. A lithium ion secondary battery comprising:
a negative electrode containing the negative electrode active material according to claim 1 as a negative electrode.

16. A method of producing a negative electrode active material containing particles of negative electrode active material containing particles of silicon compound comprising:
preparing the particles of negative electrode active material containing a silicon compound (SiO x :0.5≤x≤1.6) containing particles of silicon compound, nickel, and aluminum;
inserting Li into the particles of negative electrode active material to make at least one or more kinds of Li 2 SiO 3 and Li 4 SiO 4 , and form an aluminum-lithium alloy in at least a part of inside of the particles of silicon compound;
selecting, from the particles of negative electrode active material, particles of negative electrode active material that contain:
(a) the nickel of a mass of 2 mass ppm or more and 100 mass ppm or less relative to a mass of the particles of negative electrode active material, and
(b) the aluminum of a mass of 5 mass ppm or more and 500 mass ppm or less relative to the mass of the particles of negative electrode active material;

and
producing the negative electrode active material with the selected particles of negative electrode active material.

17. A production method of a lithium ion secondary battery comprising:
preparing a negative electrode using the negative electrode active material produced according to the production method of the negative electrode active material according to claim 16 ; and
producing a lithium ion secondary battery using the prepared negative electrode.

Assignees

• Shinetsu Chemical Co

Inventors

• Matsuno Takumi
• Hirose Takakazu
• KAMO Hiromichi
• Furuya Masahiro
• Awano Hidekazu

Classifications

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• H01M4/364 Primary

  as mixtures · CPC title

• H01M4/366

  as layered products · CPC title

• H01M4/131 Primary

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/139

  Processes of manufacture · CPC title