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

Patent metadata

Field	Value
Publication number	US-2018151873-A1
Application number	US-201615575183-A
Country	US
Kind code	A1
Filing date	Apr 21, 2016
Priority date	Jun 2, 2015
Publication date	May 31, 2018
Grant date	—

Abstract

A negative electrode active material for a non-aqueous electrolyte secondary battery, including: negative electrode active material particles that contain a silicon compound containing a Li compound; wherein the silicon compound is at least partially coated with a carbon coating, the negative electrode active material particles are coated with a coating composed of at least one of a compound having a boron-fluorine bond and a compound having a phosphorous-fluorine bond on at least a part of the surface of either or both of the silicon compound and the carbon coating, the negative electrode active material particles contain a boron or a phosphorous element in a range of 10 to 10000 ppm by mass with respect to the total amount of negative electrode active material particles. This provides a negative electrode active material for a non-aqueous electrolyte secondary battery that can increase battery capacity and improve cycle performance.

First claim

1 - 20 . (canceled)

21 . A negative electrode active material for a non-aqueous electrolyte secondary battery, comprising:
negative electrode active material particles that contain a silicon compound (SiO x : 0.5≤x≤1.6) containing a Li compound; wherein the silicon compound is at least partially coated with a carbon coating, the negative electrode active material particles are coated with a coating composed of at least one compound selected from the group consisting of a compound having a boron-fluorine bond and a compound having a phosphorous-fluorine bond, with the coating being contained on at least a part of a surface of either or both of the silicon compound and the carbon coating, the negative electrode active material particles contain a boron element or a phosphorous element in a range of 10 ppm by mass to 10000 ppm by mass with respect to a total amount of the negative electrode active material particles.

22 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein the negative electrode active material particles contain a boron element or a phosphorous element in a range of 500 ppm by mass to 5000 ppm by mass with respect to the total amount of the negative electrode active material particles.

23 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein the negative electrode active material particles contain at least one selected from the group consisting of an alkali metal, an alkaline earth metal, and a salt thereof.

24 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 23 , wherein the negative electrode active material particles contain at least one selected from the group consisting of sodium, potassium, and a salt thereof as the alkali metal, and the sodium element or the potassium element is contained in a range of 10 ppm by mass to 200 ppm by mass on an individual basis with respect to the total amount of the negative electrode active material particles.

25 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 23 , wherein the negative electrode active material particles contain at least one selected from the group consisting of magnesium, calcium, and a salt thereof as the alkaline earth metal, and the magnesium element or the calcium element is contained in a range of 5 ppm by mass to 50 ppm by mass with respect to the total amount of the negative electrode active material particles.

26 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein one or more of the surface of the silicon compound, the surface of the carbon coating, and the surface of coating composed of at least one compound selected from the group consisting of a compound having a boron-fluorine bond and a compound having a phosphorous-fluorine bond contains aluminum oxide, and an aluminum element is contained in a range of 50 ppm to 500 ppm with respect to the total amount of the negative electrode active material particles.

27 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein the negative electrode active material particles contain at least one selected from the group consisting of chromium, iron, and copper in a range of 10 ppm by mass to 500 ppm by mass with respect to the total amount of the negative electrode active material particles.

28 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein the negative electrode active material particles contain an acid and a Li salt thereof, and the acid and the Li salt thereof are on the outer periphery of the carbon coating.

29 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein the silicon compound contains in its interior at least one Li compound selected from the group consisting of Li 2 SiO 3 , Li 6 Si 2 O 7 , Li 4 SiO 4 .

30 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein the negative electrode active material particles are produced by a process including an electrochemical method.

31 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein the carbon coating exhibits scattering peaks at 1330 cm −1 and 1580 cm −1 in Raman spectrometry and satisfies 0.7<I 1330 /I 1580 <2.0 where I 1330 /I 1580 is a ratio of an intensity of the scattering peak at 1330 cm −1 to that at 1580 cm −1 .

32 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein a content of the carbon coating is 5.0% by mass or more and 20% by mass or less with respect to a mass of the negative electrode active material particles.

33 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein the silicon compound exhibits a diffraction peak having a half width (2θ) of 1.2° or more, the diffraction peak being attributable to a (111) crystal face and obtained by X-ray diffraction, and a crystallite size attributable to the crystal face is 7.5 nm or less.

34 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 , wherein the silicon compound has a median size of 0.5 μm or more and 20 μm or less.

35 . A negative electrode for a non-aqueous electrolyte secondary battery comprising a negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 21 and a carbon-based active material.

36 . The negative electrode for a non-aqueous electrolyte secondary battery according to claim 35 , wherein a ratio of the negative electrode active material for a non-aqueous electrolyte secondary battery is 5% by mass or more with respect to a total amount of the carbon-based active material and the negative electrode active material for a non-aqueous electrolyte secondary battery.

37 . A non-aqueous electrolyte secondary battery comprising a negative electrode for a non-aqueous electrolyte secondary battery according to claim 35 .

38 . A method of producing negative electrode active material particles contained in a negative electrode material for a non-aqueous electrolyte secondary battery, comprising the steps of:
producing a silicon compound shown by the general formula of SiO x (0.5≤x≤1.6), forming a carbon coating on at least a part of a surface of the silicon compound, modifying the silicon compound by inserting Li into the silicon compound to form a Li compound on either or both of the surface and the interior of the silicon compound, and coating at least a part of the surface of either or both of the silicon compound and the carbon coating with a coating composed of at least one compound selected from the group consisting of a compound having a boron-fluorine bond and a compound having a phosphorous-fluorine bond, wherein the surface is coated with the coating composed of at least one compound selected from the group consisting of a compound having a boron-fluorine bond and a compound having a phosphorous-fluorine bond in such a way that a boron element or a phosphorous element is contained in a range of 10 ppm by mass to 10000 ppm by mass with respect to a total amount of the negative electrod

Assignees

• Shinetsu Chemical Co

Inventors

• Matsuno Takumi
• KAMO Hiromichi
• Hirose Takakazu
• Yoshikawa Hiroki

Classifications

• H01M4/483

  for non-aqueous cells (H01M4/485 takes precedence) · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title