Positive electrode active material, method for manufacturing positive electrode active material, and secondary battery

Patent metadata

Field	Value
Publication number	US-12327867-B2
Application number	US-202217750436-A
Country	US
Kind code	B2
Filing date	May 23, 2022
Priority date	May 19, 2017
Publication date	Jun 10, 2025
Grant date	Jun 10, 2025

Abstract

A positive electrode active material having high capacity and excellent cycle performance is provided. The positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charge and discharge as compared with those of a known positive electrode active material.

First claim

The invention claimed is:

1. A lithium ion secondary battery comprising a positive electrode, a negative electrode, and an electrolyte solution:
wherein:
the positive electrode comprises a positive electrode active material comprising a positive electrode active material particle, the positive electrode active material particle comprising lithium cobalt oxide, magnesium, and aluminum,
a magnesium concentration in a surface portion of the positive electrode active material particle is higher than a magnesium concentration in an inner portion of the positive electrode active material particle,
in an EDX linear analysis of the positive electrode active material particle, a concentration peak of aluminum is located in a deeper region than a concentration peak of magnesium,
the positive electrode active material has an O3 crystal structure when a charge depth of the positive electrode active material is 0.06 or less,
an X-ray diffraction pattern of the positive electrode active material has at least a first diffraction peak at 2 θ of 19.30+0.20° and a second diffraction peak at 2θ of 45.55=0.10° when the positive electrode is analyzed by powder X-ray diffraction by using CuKal ray, when a battery comprising the positive electrode and a counter electrode of lithium is charged at 4.6V, and
the electrolyte solution comprises vinylene carbonate.

2. The lithium ion secondary battery according to claim 1 , wherein the positive electrode active material particle further comprises fluorine.

3. The lithium ion secondary battery according to claim 1 , wherein, in a crystal structure of the positive electrode active material, coordinate of cobalt is represented by (0, 0, 0.5) and coordinate of oxygen is represented by (0, 0, x), where x is defined as 0.20≤×≤0.25, when the positive electrode is analyzed by powder X-ray diffraction when the battery with the positive electrode and the counter electrode of lithium is charged at 4.6V.

4. The lithium ion secondary battery according to claim 1 , wherein the surface portion of the positive electrode active material particle is a region from a surface of the positive electrode active material particle to a depth of approximately 10 nm.

5. A lithium ion secondary battery comprising a positive electrode, a negative electrode, and an electrolyte solution:
wherein:
the positive electrode comprises a positive electrode active material comprising a positive electrode active material particle, the positive electrode active material particle comprising lithium cobalt oxide, magnesium, and aluminum,
a magnesium concentration in a surface portion of the positive electrode active material particle is higher than a magnesium concentration in an inner portion of the positive electrode active material particle,
in an EDX linear analysis of the positive electrode active material particle, a concentration peak of aluminum is located in a deeper region than a concentration peak of magnesium,
an X-ray diffraction pattern of the positive electrode active material has at least a first diffraction peak at 2θ of 19.30+0.20° and a second diffraction peak at 2 θ of 45.55+0.10° when the positive electrode is analyzed by powder X-ray diffraction by using CuKα1 ray, when a battery comprising the positive electrode and a counter electrode of lithium is charged at 4.6V, and
the electrolyte solution comprises vinylene carbonate.

6. The lithium ion secondary battery according to claim 5 , wherein the positive electrode active material particle further comprises fluorine.

7. The lithium ion secondary battery according to claim 5 , wherein, in a crystal structure of the positive electrode active material, coordinate of cobalt is represented by (0, 0, 0.5) and coordinate of oxygen is represented by (0, 0, x), where x is defined as 0.20≤×≤0.25, when the positive electrode is analyzed by powder X-ray diffraction when the battery with the positive electrode and the counter electrode of lithium is charged at 4.6V.

8. The lithium ion secondary battery according to claim 5 , wherein the surface portion of the positive electrode active material particle is a region from a surface of the positive electrode active material particle to a depth of approximately 10 nm.

9. The lithium ion secondary battery according to claim 5 ,
wherein the battery with the positive electrode and the counter electrode of lithium is charged by CCCV charge.

10. The lithium ion secondary battery according to claim 5 ,
wherein a unit cell volume of a crystal structure of the positive electrode active material is 94.39 Å 3 or greater when the battery comprising the positive electrode and the counter electrode of lithium is charged at 4.6V.

11. A lithium ion secondary battery comprising:
a positive electrode comprising a positive electrode active material comprising a positive electrode active material particle, the positive electrode active material particle comprising lithium cobalt oxide, magnesium, and aluminum,
wherein:
a magnesium concentration in a surface portion of the positive electrode active material particle is higher than a magnesium concentration in an inner portion of the positive electrode active material particle,
in an EDX linear analysis of the positive electrode active material particle, a concentration peak of aluminum is located in a deeper region than a concentration peak of magnesium,
the positive electrode active material has an O3 crystal structure when a charge depth of the positive electrode active material is 0.06 or less, and
an X-ray diffraction pattern of the positive electrode active material has at least a first diffraction peak at 2 θ of 19.30+0.20° and a second diffraction peak at 2 θ of 45.55+0.10° when the positive electrode is analyzed by powder X-ray diffraction by using CuKα1 ray, when a battery comprising the positive electrode and a counter electrode of lithium is charged at 4.6V.

12. The lithium ion secondary battery according to claim 11 , wherein the positive electrode active material particle further comprises fluorine.

13. The lithium ion secondary battery according to claim 11 ,
wherein the positive electrode active material comprises a first region comprising a crystal grain boundary and a second region not comprising a crystal grain boundary, and
wherein a concentration of magnesium in the crystal grain boundary or its vicinity in the first region is higher than a concentration of magnesium in the second region.

14. The lithium ion secondary battery according to claim 11 , wherein, in a crystal structure of the positive electrode active material, coordinate of cobalt is represented by (0, 0, 0.5) and coordinate of oxygen is represented by (0, 0, x), where x is defined as 0.20≤×≤0.25, when the positive electrode is analyzed by powder X-ray diffraction when the battery with the positive electrode and the counter electrode of lithium is charged at 4.6V.

15. The lithium ion secondary battery according to claim 11 ,
wherein the positive electrode comprises a conductive additive, and
wherein the conductive additive includes carbon nanotube or graphene.

16. A lithium ion secondary battery comprising:
a positive electrode comprising a positive electrode active material comprising a positive electrode active material particle, the positive electrode active material particle comprising lithium cobalt oxide, magnesium, and aluminum,
wherein:
in an EDX linear analysis of the positive electrode active material particle, a concentration peak of aluminum is located in a deeper region than a concentration peak of magnesium, and
an X-ray diffraction pattern of the posit

Assignees

• Semiconductor Energy Lab

Inventors

• Mikami Mayumi
• Uchida Aya
• Yoneda Yumiko
• Momma Yohei
• Takahashi Masahiro
• Ochiai Teruaki

Classifications

• H01M4/587

  for inserting or intercalating light metals · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• H01B1/08

  oxides · CPC title

• H01M6/164

  by the solvent · CPC title

• H01M2004/028

  Positive electrodes · CPC title