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

Patent metadata

Field	Value
Publication number	US-2018175377-A1
Application number	US-201615580556-A
Country	US
Kind code	A1
Filing date	May 10, 2016
Priority date	Jun 17, 2015
Publication date	Jun 21, 2018
Grant date	—

Abstract

A negative electrode active material for a non-aqueous electrolyte secondary battery, includes: 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, and at least a part of a surface of the silicon compound, a surface of the carbon coating, or both of them are coated with a composite layer that contains a composite composed of amorphous metal oxide and metal hydroxide. This provides a negative electrode active material for a non-aqueous electrolyte secondary battery that is highly stable in aqueous slurry, having a high capacity, favorable cycle performance and first efficiency.

First claim

1 - 13 . (canceled)

14 . 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, and at least a part of a surface of the silicon compound, a surface of the carbon coating, or both of them is coated with a composite layer that contains a composite composed of amorphous metal oxide and metal hydroxide.

15 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 14 , wherein the metal oxide and the metal hydroxide contain at least one element selected from the group consisting of aluminum, magnesium, titanium, and zirconium.

16 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 14 , wherein the composite layer has a thickness of 10 nm or less.

17 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 15 , wherein the composite layer has a thickness of 10 nm or less.

18 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 16 , wherein the composite layer has a thickness of 5 nm or less.

19 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 17 , wherein the composite layer has a thickness of 5 nm or less.

20 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 14 , wherein the silicon compound contains Li 2 SiO 3 , as the Li compound.

21 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 15 , wherein the silicon compound contains Li 2 SiO 3 , as the Li compound.

22 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 16 , wherein the silicon compound contains Li 2 SiO 3 as the Li compound.

23 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 17 , wherein the silicon compound contains Li 2 SiO 3 as the Li compound.

24 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 18 , wherein the silicon compound contains Li 2 SiO 3 as the Li compound.

25 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 19 , wherein the silicon compound contains Li 2 SiO 3 as the Li compound.

26 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 14 , wherein the silicon compound has a peak attributable to SiO 2 -region given in the chemical shift value of −95 to −150 ppm in a 29 Si-MAS-NMR spectrum.

27 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 14 , wherein the silicon compound satisfies a relationship of A>B where A and B are respectively an intensity of a peak attributable to Li 2 SiO 3 given in the chemical shift value in the vicinity of −75 ppm and an intensity of a peak attributable to SiO 2 -region given in the chemical shift value of −95 to −150 ppm in a 29 Si-MAS-NMR spectrum.

28 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 14 , wherein
a test cell composed of a negative electrode produced by using a negative electrode active material in which the negative electrode active material for a non-aqueous electrolyte secondary battery and a carbon-based active material are mixed, together with a lithium counter electrode, exhibits a peak at an electric potential V of the negative electrode ranging from 0.40 V to 0.55 V in discharging when the test cell is charged and discharged to graph a relationship between a derivative dQ/dV of a discharging capacity Q with respect to the electric potential V of the negative electrode on the basis of the lithium counter electrode, together with the electric potential V, where current flows in a direction in which the lithium of the negative electrode active material for a non-aqueous electrolyte secondary battery is extracted in the discharging.

29 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 14 , 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 Si(111) crystal face and obtained by X-ray diffraction, and a crystallite size attributable to the crystal face is 7.5 nm or less.

30 . The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 14 , wherein the silicon compound has a median size of 0.5 μm or more and 15 μm or less.

31 . A non-aqueous electrolyte secondary battery comprising the negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 14 .

32 . A method of producing a negative electrode material for a non-aqueous electrolyte secondary battery containing negative electrode active material particles, comprising the steps of:
producing silicon oxide particles shown by the general formula of SiO x (0.5≤x≤1.6), coating each surface of the silicon oxide particles with a carbon coating, subjecting the silicon oxide particles coated with the carbon coating to insertion and extraction of Li to modify the silicon oxide particles, and forming a composite layer that contains a composite composed of amorphous metal oxide and metal hydroxide to coat each surface of the modified silicon oxide particles with the composite layer, wherein the negative electrode material for a non-aqueous electrolyte secondary battery is produced by using the silicon oxide particles coated with the composite layer.

33 . The method of producing a negative electrode material for a non-aqueous electrolyte secondary battery according to claim 32 , wherein the composite layer is formed on the surface of the modified silicon oxide particles by hydrolysis and dehydration condensation of metal alkoxide in the step of forming a composite layer.

Assignees

• Shinetsu Chemical Co

Inventors

• Hirose Takakazu
• KAMO Hiromichi

Classifications

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/1393

  of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/62

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

• H01M4/139

  Processes of manufacture · CPC title