Positive electrode active material, positive electrode, secondary battery, electronic device, and vehicle

Patent metadata

Field	Value
Publication number	US-2025279424-A1
Application number	US-202318858791-A
Country	US
Kind code	A1
Filing date	Apr 12, 2023
Priority date	Apr 25, 2022
Publication date	Sep 4, 2025
Grant date	—

Abstract

A positive electrode active material which inhibits a decrease in discharge capacity during charge and discharge cycles and a secondary battery which includes the positive electrode active material are provided. The secondary battery includes a positive electrode active material. The positive electrode active material contains lithium cobalt oxide. A total mass of magnesium oxide and tricobalt tetraoxide estimated by Rietveld analysis of a pattern obtained by powder X-ray diffraction of the positive electrode active material is less than or equal to 3% with respect to a mass of the lithium cobalt oxide. A volume resistivity of a powder of the positive electrode active material is higher than or equal to 1.0E+8 Ω·cm and lower than or equal to 1.0E+10 Ω·cm under a pressure of 64 MPa.

First claim

1 . A positive electrode active material comprising:
lithium cobalt oxide, wherein the lithium cobalt oxide comprises magnesium, wherein a total mass of magnesium oxide and tricobalt tetraoxide estimated by Rietveld analysis of a pattern obtained by powder X-ray diffraction of the positive electrode active material is less than or equal to 3% with respect to a mass of the lithium cobalt oxide, and wherein a volume resistivity of a powder of the positive electrode active material is higher than or equal to 1.0×10 8 Ω·cm and lower than or equal to 1.0×10 10 Ω·cm under a pressure of 64 MPa.

2 . The positive electrode active material according to claim 1 ,
wherein the lithium cobalt oxide has a layered rock-salt crystal structure belonging to a space group R-3m.

3 . The positive electrode active material according to claim 2 ,
wherein the lithium cobalt oxide further comprises aluminum and nickel.

4 . The positive electrode active material according to claim 3 ,
wherein the lithium cobalt oxide comprises the magnesium and the aluminum in a surface portion, wherein the surface portion is a region to less than or equal to 50 nm from a surface of the lithium cobalt oxide, and wherein the lithium cobalt oxide comprises a region where a peak of the magnesium is closer to the surface of the lithium cobalt oxide than a peak of the aluminum is in line analysis of Energy Dispersive X-ray Spectroscopy in a depth direction.

5 . The positive electrode active material according to claim 4 ,
wherein the surface portion comprises a basal region having a surface parallel to a (00/) plane of the layered rock-salt crystal structure and an edge region having a surface in a direction intersecting the (00/) plane, wherein the edge region comprises the nickel, and wherein the edge region of the lithium cobalt oxide comprises a region where distribution of the magnesium and distribution of the nickel overlap with each other when the EDX line analysis in the depth direction is performed.

6 . The positive electrode active material according to claim 5 ,
wherein the nickel is substantially absent from the basal region.

7 . A positive electrode comprising the positive electrode active material according to claim 1 .

8 . A secondary battery comprising the positive electrode according to claim 7 .

9 . An electronic device comprising the secondary battery according to claim 8 .

10 . A vehicle comprising the secondary battery according to claim 9 .

Assignees

• Semiconductor Energy Lab

Inventors

• Kawatsuki Atsushi
• Saito Jo
• Tanemura Kazuki
• Momma Yohei
• Mikami Mayumi
• Ogita Kaori

Classifications

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/36

  Selection of substances as active materials, active masses, active liquids · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title