Negative electrode of secondary battery, and secondary battery using the negative electrode

Patent metadata

Field	Value
Publication number	US-2026094828-A1
Application number	US-202519325496-A
Country	US
Kind code	A1
Filing date	Sep 11, 2025
Priority date	Sep 27, 2024
Publication date	Apr 2, 2026
Grant date	—

Abstract

The negative electrode includes a negative electrode current collector, and a negative electrode active material layer supported by the negative electrode current collector. The negative electrode active material layer includes a first layer existing on a side of a surface layer part and a second layer existing on a side of the negative electrode current collector. The first layer includes first graphite particles and first Si-containing particles. The second layer includes second graphite particles and second Si-containing particles. The Si content ratio in the first Si-containing particle is smaller than that in the second Si-containing particle. Each of the first Si-containing particle and the second Si-containing particle is coated with a conductive material. The ratio of the coating amount (mass %) of the conductive material for the second Si-containing particle to the coating amount (mass %) of the conductive material for the first Si-containing particle is 2.5 or more.

First claim

What is claimed is:

1 . A negative electrode comprising:
a negative electrode current collector; and a negative electrode active material layer supported by the negative electrode current collector, wherein the negative electrode active material layer includes a first layer existing on a side of a surface layer part and a second layer existing on a side of the negative electrode current collector, the first layer includes first graphite particles and first Si-containing particles, the second layer includes second graphite particles and second Si-containing particles, a Si content ratio in the first Si-containing particle is smaller than a Si content ratio in the second Si-containing particle, each of the first Si-containing particle and the second Si-containing particle is coated with a conductive material, and a ratio of a coating amount (mass %) of the conductive material for the second Si-containing particle to a coating amount (mass %) of the conductive material for the first Si-containing particle is 2.5 or more.

2 . The negative electrode according to claim 1 , wherein the conductive material is a carbon nanotube.

3 . The negative electrode according to claim 2 , wherein the coating amount of the conductive material for the first Si-containing particle is 0.05 mass % to 2.0 mass %, and the coating amount of the conductive material for the second Si-containing particle is 0.10 mass % to 3.0 mass %.

4 . The negative electrode according to claim 1 , wherein a ratio of a thickness of the second layer to a thickness of the first layer is 10/90 to 90/10.

5 . The negative electrode according to claim 1 , wherein a ratio of the Si content ratio in the first Si-containing particle to the Si content ratio in the second Si-containing particle is 0.10 to 0.90.

6 . The negative electrode according to claim 1 , wherein the Si content ratio in the first Si-containing particle is 20 mass % to 55 mass %, and the Si content ratio in the second Si-containing particle is 45 mass % to 80 mass %.

7 . The negative electrode according to claim 1 , wherein each of the first Si-containing particles and the second Si-containing particles is particles of a Si—C composite material.

8 . The negative electrode according to claim 1 , wherein
in the first layer, a mass ratio of the first Si-containing particles to a total of the first graphite particles and the first Si-containing particles is 10 mass % to 60 mass %, and in the second layer, a mass ratio of the second Si-containing particles to a total of the second graphite particles and the second Si-containing particles is 10 mass % to 60 mass %.

9 . A secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode is the negative electrode according to claim 1 .

Assignees

• Prime Planet Energy & Solutions Inc

Inventors

• Onodera Naoto

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/133

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

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/366

  as layered products · CPC title