Positive electrode active material, lithium ion battery, electronic device, and vehicle

Patent metadata

Field	Value
Publication number	US-2025279425-A1
Application number	US-202318858957-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 lithium ion battery having excellent charge performance and discharge performance even in a low-temperature environment is provided. A lithium ion battery includes a positive electrode active material containing cobalt, oxygen, magnesium, aluminum, and nickel. The median diameter of the positive electrode active material is greater than or equal to 1 μm and less than or equal to 12 μm. Magnesium and aluminum are included in a surface portion. The surface portion is a region within 50 nm in depth from the surface of the positive electrode active material. The positive electrode active material includes a region where magnesium is distributed closer to the surface side of the positive electrode active material than aluminum is.

First claim

1 . A positive electrode active material comprising:
cobalt, oxygen, magnesium, aluminum, and nickel, wherein a median diameter of the positive electrode active material is greater than or equal to 1 μm and less than or equal to 12 μm, wherein the positive electrode active material comprises the magnesium and the aluminum in a surface portion, wherein the surface portion is a region within 50 nm in depth from a surface of the positive electrode active material, and wherein when the positive electrode active material is subjected to EDX line analysis in a depth direction, the positive electrode active material comprises a region where the magnesium is distributed closer to a surface side of the positive electrode active material than the aluminum is.

2 . The positive electrode active material according to claim 1 ,
wherein the positive electrode active material has a layered rock-salt crystal structure belonging to a space group R-3m, wherein the surface portion comprises a basal region comprising a surface parallel to a (001) plane of the crystal structure and an edge region comprising a surface in a direction intersecting with the (001) plane, and wherein when the positive electrode active material is subjected to EDX line analysis in the depth direction, the edge region comprises a region where distribution of the magnesium and distribution of the nickel overlap with each other.

3 . The positive electrode active material according to claim 2 ,
wherein the nickel is substantially absent in the basal region.

4 . The positive electrode active material according to claim 1 ,
wherein when the positive electrode active material is analyzed by XPS, a number of atoms of the magnesium with respect to a number of atoms of the cobalt, Mg/Co, is greater than or equal to 0.400 and less than or equal to 1.500, and wherein a number of atoms of the nickel with respect to the number of the atoms of the cobalt, Ni/Co, is greater than or equal to 0.050 and less than or equal to 0.150.

5 . The positive electrode active material according to claim 4 ,
further comprising fluorine, wherein when the positive electrode active material is analyzed by XPS, a number of atoms of the fluorine with respect to the number of the atoms of the cobalt, F/Co, is greater than or equal to 0.100 and less than or equal to 1.000.

6 . A lithium ion battery comprising:
a positive electrode comprising the positive electrode active material according to claim 1 ; and an electrolyte, wherein the electrolyte comprises lithium hexafluorophosphate, ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate.

7 . The lithium ion battery according to claim 6 ,
wherein given that a volume of a total content of the ethylene carbonate, the ethyl methyl carbonate, and the dimethyl carbonate in the electrolyte is 100 vol %, a volume ratio between the ethylene carbonate, the ethyl methyl carbonate, and the dimethyl carbonate is x:y:100-x-y, where 5≤x≤35 and 0<y<65.

8 . The lithium ion battery according to claim 7 ,
wherein the electrolyte comprises the lithium hexafluorophosphate of more than or equal to 0.5 mol/L and less than or equal to 1.5 mol/L with respect to the volume of the total content of the ethylene carbonate, the ethyl methyl carbonate, and the dimethyl carbonate.

9 . An electronic device comprising the lithium ion battery according to claim 6 .

10 . A vehicle comprising the lithium ion battery according to claim 6 .

Assignees

• Semiconductor Energy Lab

Inventors

• Saito Jo
• Kawatsuki Atsushi
• Momma Yohei
• Yoshitomi Shuhei
• Nakanishi Kenta
• Kakehata Tetsuya

Classifications

• H01M4/36

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

• H01M2300/0034

  Fluorinated solvents · CPC title

• H01M2004/028

  Positive electrodes · 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