Positive Electrode Active Material, Method for Manufacturing Positive Electrode Active Material, and Secondary Battery

Patent metadata

Field	Value
Publication number	US-2020313177-A1
Application number	US-202016900108-A
Country	US
Kind code	A1
Filing date	Jun 12, 2020
Priority date	Nov 18, 2016
Publication date	Oct 1, 2020
Grant date	—

Abstract

Provided is a positive electrode active material for a lithium ion secondary battery having favorable cycle characteristics and high capacity. A covering layer containing aluminum and a covering layer containing magnesium are provided on a superficial portion of the positive electrode active material. The covering layer containing magnesium exists in a region closer to a particle surface than the covering layer containing aluminum is. The covering layer containing aluminum can be formed by a sol-gel method using an aluminum alkoxide. The covering layer containing magnesium can be formed as follows: magnesium and fluorine are mixed as a starting material and then subjected to heating after the sol-gel step, so that magnesium is segregated.

First claim

1 - 4 . (canceled)

5 . A lithium-ion secondary battery comprising:
a positive electrode comprising a positive electrode active material and a conductive additive, wherein the positive electrode active material comprises a composite oxide containing lithium and cobalt, wherein the positive electrode active material comprises the cobalt, aluminum, magnesium, and fluorine in a superficial portion of the positive electrode active material, and wherein the conductive additive comprises carbon fiber, graphene, or multilayer graphene.

6 . The lithium-ion secondary battery according to claim 5 ,
wherein the magnesium comprises a region where the magnesium is closer to a surface of the positive electrode active material than the aluminum is.

7 . The lithium-ion secondary battery according to claim 5 ,
wherein the magnesium comprises a region where the magnesium is closer to a surface of the positive electrode active material than the aluminum is, and wherein the fluorine comprises a region where the fluorine is closer to the surface of the positive electrode active material than the aluminum is.

8 . The lithium-ion secondary battery according to claim 5 ,
wherein a peak of a concentration of the magnesium is present in a region closer to a surface of the positive electrode active material than a peak of a concentration of the aluminum is in energy dispersive X-ray spectrometry.

9 . The lithium-ion secondary battery according to claim 5 ,
wherein each of a peak of a concentration of the magnesium and a peak of a concentration of the fluorine is present in a region closer to a surface of the positive electrode active material than a peak of a concentration of the aluminum is in energy dispersive X-ray spectrometry.

10 . The lithium-ion secondary battery according to claim 5 ,
wherein a concentration of the magnesium is more than or equal to 5 atomic % and less than or equal to 20 atomic %, and wherein the concentration of the magnesium is measured with X-ray photoelectron spectroscopy by taking a total amount of lithium, aluminum, cobalt, oxygen, magnesium, and fluorine as 100 atomic %.

11 . The lithium-ion secondary battery according to claim 5 ,
wherein a concentration of the fluorine is more than or equal to 3.5 atomic % and less than or equal to 14 atomic %, and wherein the concentration of the fluorine is measured with X-ray photoelectron spectroscopy by taking a total amount of lithium, aluminum, cobalt, oxygen, magnesium, and fluorine as 100 atomic %.

12 . The lithium-ion secondary battery according to claim 5 ,
wherein a concentration of the aluminum is more than or equal to 0.1 atomic % and less than or equal to 10 atomic %, and wherein the concentration of the aluminum is measured with X-ray photoelectron spectroscopy by taking a total amount of lithium, aluminum, cobalt, oxygen, magnesium, and fluorine as 100 atomic %.

13 . The lithium-ion secondary battery according to claim 5 , wherein the carbon fiber is carbon nanofiber or carbon nanotube.

14 . The lithium-ion secondary battery according to claim 5 , further comprising:
a negative electrode; an electrolyte; and an exterior body, wherein the negative electrode comprises a negative electrode active material, and wherein the negative electrode active material comprises a carbon-based material.

15 . The lithium-ion secondary battery according to claim 14 ,
wherein the carbon-based material is graphite.

16 . The lithium-ion secondary battery according to claim 14 ,
wherein the electrolyte comprises LiPF 6 .

17 . An electronic device comprising the lithium-ion secondary battery according to claim 5 .

18 . An electronic device comprising:
the lithium-ion secondary battery according to claim 5 ; and a protection circuit electrically connected to the lithium-ion secondary battery, wherein the protection circuit has a function of preventing overcharge of the lithium-ion secondary battery.

19 . A lithium-ion secondary battery comprising:
a positive electrode comprising a positive electrode active material and a conductive additive, wherein the positive electrode active material comprises a composite oxide containing lithium and cobalt, wherein the positive electrode active material comprises aluminum, magnesium, and fluorine, wherein a peak of a concentration of the magnesium is present in a region from a surface of the positive electrode active material to a depth of 3 nm in line analysis of energy dispersive X-ray spectrometry, and wherein the conductive additive comprises carbon fiber, graphene, or multilayer graphene.

20 . The lithium-ion secondary battery according to claim 19 ,
wherein the magnesium comprises a region where the magnesium is closer to the surface of the positive electrode active material than the aluminum is.

21 . The lithium-ion secondary battery according to claim 19 ,
wherein the magnesium comprises a region where the magnesium is closer to the surface of the positive electrode active material than the aluminum is, and wherein the fluorine comprises a region where the fluorine is closer to the surface of the positive electrode active material than the aluminum is.

22 . The lithium-ion secondary battery according to claim 19 ,
wherein the peak of the concentration of the magnesium is present in a region closer to the surface of the positive electrode active material than a peak of a concentration of the aluminum is in line analysis of energy dispersive X-ray spectrometry.

23 . The lithium-ion secondary battery according to claim 19 ,
wherein each of the peak of the concentration of the magnesium and a peak of a concentration of the fluorine is present in a region closer to the surface of the positive electrode active material than a peak of a concentration of the aluminum is in line analysis of energy dispersive X-ray spectrometry.

24 . The lithium-ion secondary battery according to claim 19 ,
wherein a peak of a concentration of the fluorine is present in a region from the surface of the positive electrode active material to a depth of 3 nm in line analysis of energy dispersive X-ray spectrometry.

25 . The lithium-ion secondary battery according to claim 19 , further comprising:
a negative electrode; an electrolyte; and an exterior body, wherein the negative electrode comprises a negative electrode active material, and wherein the negative electrode active material comprises a carbon-based material.

26 . The lithium-ion secondary battery according to claim 25 ,
wherein the carbon-based material is graphite.

27 . The lithium-ion secondary battery according to claim 25 ,
wherein the electrolyte comprises LiPF 6 .

28 . An electronic device comprising the lithium-ion secondary battery according to claim 19 .

29 . An electronic device comprising:
the lithium-ion secondary battery according to claim 19 ; and a protection circuit electrically connected to the lithium-ion secondary battery, wherein the protection circuit has a function of preventing overcharge of the lithium-ion secondary battery.

30 . A lithium-ion secondary battery comprising:
a positive electrode comprising a positive electrode active material and a conductive additive, wherein the positive electrode active material comprises a composite oxide containing lithium and cobalt, wherein the positive electrode active materia

Assignees

• Semiconductor Energy Lab

Inventors

• Momma Yohei
• Kawakami Takahiro
• Ochiai Teruaki
• Takahashi Masahiro

Classifications

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M2004/021

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

• C01P2002/85

  by XPS, EDX or EDAX data · CPC title

• H01M4/625

  Carbon or graphite · CPC title