Positive electrode composition for lithium ion secondary battery, positive electrode for lithium ion secondary battery, and lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-12249709-B2
Application number	US-201917047384-A
Country	US
Kind code	B2
Filing date	Apr 26, 2019
Priority date	May 8, 2018
Publication date	Mar 11, 2025
Grant date	Mar 11, 2025

Abstract

A positive electrode composition for a lithium ion secondary battery includes an active material that can occlude and release lithium ions and a conductive material, wherein the active material is a lithium cobalt composite oxide; the conductive material is carbon black and carbon nanotubes; the carbon black has a BET specific surface area of 100 to 400 m 2 /g and a DBP absorption amount of 210 to 400 ml/100 g; the carbon nanotubes have an average diameter of 20 nm or less, a BET specific surface area of 170 m 2 /g or more, and an aspect ratio of 50 or more; and a carbon black content X (unit: % by mass) and a carbon nanotube content Y (unit: % by mass) in the positive electrode composition satisfy the following conditions (A) and (B): (A) 0.5≤(X+Y)≤2.0; (B) 0.80≤{X/(X+Y)}≤0.95.

First claim

The invention claimed is:

1. A positive electrode composition for a lithium ion secondary battery, comprising an active material that can occlude and release lithium ions and a conductive material, wherein
the active material is a lithium cobalt composite oxide in which lithium and cobalt are the only metal components;
the conductive material is carbon black and carbon nanotubes, wherein the carbon black and the carbon nanotubes are separately dispersed in the active material;
all the carbon black comprised in the positive electrode composition has a BET specific surface area of 133 to 400 m 2 /g and a DBP absorption amount of 210 to 400 ml/100 g;
the carbon nanotubes have an average diameter of 20 nm or less, a BET specific surface area of 170 m 2 /g or more, and an aspect ratio of 50 or more, wherein the BET specific surface area of carbon black and the carbon nanotubes are measured separately; and
a carbon black content X (unit: % by mass) and a carbon nanotube content Y (unit: % by mass) in the positive electrode composition satisfy the following conditions (A) and (B):
0.5≤( X+Y )≤2.0  (A)

0.80≤{ X /( X+Y )}≤0.95.  (B)

2. The positive electrode composition for a lithium ion secondary battery according to claim 1 , wherein the lithium cobalt composite oxide has an average particle diameter D 50 of 10 to 20 μm.

3. The positive electrode composition for a lithium ion secondary battery according to claim 1 , wherein the BET specific surface area of the carbon nanotubes is larger than 200 m 2 /g.

4. The positive electrode composition for a lithium ion secondary battery according to claim 1 , wherein the positive electrode composition for a lithium ion secondary battery comprises 96% by mass or more and lower than 99.5% by mass of the lithium cobalt composite oxide.

5. A positive electrode for a lithium ion secondary battery comprising the positive electrode composition for a lithium ion secondary battery according to claim 1 .

6. A lithium ion secondary battery comprising the positive electrode for a lithium ion secondary battery according to claim 5 .

7. The positive electrode composition for a lithium ion secondary battery according to claim 1 , wherein the carbon black forms conductive paths between the active material, and the carbon nanotubes form conductive paths on a surface of the active material.

Assignees

• Denka Company Ltd

Inventors

• Nagai Tatsuya
• Osumi Shinichiro
• Ito Tetsuya

Classifications

• 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

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/131 Primary

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

• H01M4/625 Primary

  Carbon or graphite · CPC title