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

Patent metadata

Field	Value
Publication number	US-2020313178-A1
Application number	US-202016901118-A
Country	US
Kind code	A1
Filing date	Jun 15, 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

What is claimed is:

1 . A lithium-ion secondary battery comprising:
a positive electrode comprising a positive electrode active material; and a negative electrode, wherein the positive electrode active material comprises cobalt, aluminum, and fluorine in a superficial portion of the positive electrode active material, wherein the aluminum has a concentration gradient in the superficial portion of the positive electrode active material, and wherein a peak of the fluorine is present in a region closer to a surface of the positive electrode active material than a peak of the aluminum is in line analysis of energy dispersive X-ray spectrometry.

2 . The lithium-ion secondary battery according to claim 1 ,
wherein the peak 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, and wherein the peak of the aluminum is present at a depth of 0.5 nm or more and 20 nm or less from the surface of the positive electrode active material in line analysis of energy dispersive X-ray spectrometry.

3 . A lithium-ion secondary battery comprising:
a positive electrode comprising a positive electrode active material; and a negative electrode, wherein the positive electrode active material comprises a first region, a second region, and a third region, wherein the first region comprises cobalt, wherein the second region comprises aluminum and cobalt, wherein the third region comprises fluorine, wherein each of the second region and the third region is in a superficial portion of the positive electrode active material, wherein the aluminum has a concentration gradient in the second region, and wherein a peak of the fluorine is present in a region closer to a surface of the positive electrode active material than a peak of the aluminum is in line analysis of energy dispersive X-ray spectrometry.

4 . The lithium-ion secondary battery according to claim 3 ,
wherein the peak of the fluorine is present in a region from the surface of the positive electrode active material to a depth of 3 nm, and wherein the peak of the aluminum is present at a depth of 0.5 nm or more and 20 nm or less from the surface of the positive electrode active material.

5 . The lithium-ion secondary battery according to claim 3 ,
wherein the second region covers at least a part of the first region, and wherein the third region covers at least a part of the second region.

6 . The lithium-ion secondary battery according to claim 3 ,
wherein the second region covers at least a part of the first region, wherein the third region covers at least a part of the second region, wherein the peak of the fluorine is present in a region from the surface of the positive electrode active material to a depth of 3 nm, and wherein the peak of the aluminum is present at a depth of 0.5 nm or more and 20 nm or less from the surface of the positive electrode active material.

7 . A hybrid electric vehicle comprising the lithium-ion secondary battery according to claim 1 .

8 . A hybrid electric vehicle comprising the lithium-ion secondary battery according to claim 3 .

9 . An electric vehicle comprising the lithium-ion secondary battery according to claim 1 .

10 . An electric vehicle comprising the lithium-ion secondary battery according to claim 3 .

11 . A plug-in hybrid electric vehicle comprising the lithium-ion secondary battery according to claim 1 .

12 . A plug-in hybrid electric vehicle comprising the lithium-ion secondary battery according to claim 3 .

13 . A lithium-ion secondary battery comprising:
a positive electrode comprising a positive electrode active material; and a negative electrode, wherein the positive electrode active material comprises cobalt, aluminum, and fluorine in a superficial portion of the positive electrode active material, wherein a peak of the fluorine is present in a region closer to a surface of the positive electrode active material than a peak of the aluminum is in line analysis of energy dispersive X-ray spectrometry.

14 . A lithium-ion secondary battery comprising:
a positive electrode comprising a positive electrode active material; and a negative electrode, wherein the positive electrode active material comprises cobalt, aluminum, and fluorine, wherein a peak of the fluorine 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, wherein a peak of the aluminum is present at a depth of 0.5 nm or more and 20 nm or less from the surface of the positive electrode active material in line analysis of energy dispersive X-ray spectrometry, and wherein the peak of the fluorine and the peak of the aluminum are present in different regions in line analysis of energy dispersive X-ray spectrometry.

15 . The lithium-ion secondary battery according to claim 14 ,
wherein the peak of the fluorine is present in a region closer to the surface of the positive electrode active material than the peak of the aluminum is in line analysis of energy dispersive X-ray spectrometry.

16 . A lithium-ion secondary battery comprising:
a positive electrode comprising a positive electrode active material; and a negative electrode, wherein the positive electrode active material comprises a first region, a second region, and a third region, wherein the first region comprises cobalt, wherein the second region comprises aluminum and cobalt, wherein the third region comprises fluorine, and wherein each of the second region and the third region is in a superficial portion of the positive electrode active material, and wherein a peak of the fluorine and a peak of the aluminum are present in different regions in line analysis of energy dispersive X-ray spectrometry.

17 . The lithium-ion secondary battery according to claim 16 ,
wherein the peak of the fluorine 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 peak of the aluminum is present at a depth of 0.5 nm or more and 20 nm or less from the surface of the positive electrode active material in line analysis of energy dispersive X-ray spectrometry.

18 . The lithium-ion secondary battery according to claim 16 ,
wherein the peak of the fluorine 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, wherein the peak of the aluminum is present at a depth of 0.5 nm or more and 20 nm or less from the surface of the positive electrode active material in line analysis of energy dispersive X-ray spectrometry, and wherein the peak of the fluorine is present in a region closer to the surface of the positive electrode active material than the peak of the aluminum is in line analysis of energy dispersive X-ray spectrometry.

19 . The lithium-ion secondary battery according to claim 16 ,
wherein the second region covers at least a part of the first region, and wherein the third region covers at least a part of the second region.

20 . The lithium-ion secondary battery according to claim 16 ,
wherein the second region covers at least a part of the first region, wherein the third region covers at least a part of the second region, wherein the peak of the fluorine is present in a region from a surface o

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