Negative electrode for non-aqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-10319993-B2
Application number	US-201415108097-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 26, 2013
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

Gas evolution during the high-temperature storage of a non-aqueous electrolyte secondary battery is suppressed to improve the high-temperature storage characteristics of the non-aqueous electrolyte secondary battery. A negative electrode for a non-aqueous electrolyte secondary battery contains silicon-containing particles and graphite particles. A covering layer is disposed on each of the graphite particles. The covering layer contains a first covering material and a second covering material, the first covering material containing particles that can be made to swell with a non-aqueous electrolytic solution, the second covering material containing a water-soluble polymer material. The first covering material is disposed on a surface of each of the graphite particles. The mass ratio of the second covering material to the first covering material is higher than 1.

First claim

The invention claimed is:

1. A negative electrode for a non-aqueous electrolyte secondary battery, the negative electrode comprising silicon-containing particles and graphite particles,
wherein a covering layer is disposed on each of the graphite particles,
the covering layer contains a first covering material and a second covering material, the first covering material containing particles that can be made to swell with a non-aqueous electrolytic solution, the second covering material containing a water-soluble polymer material,
the first covering material is disposed on a surface of each of the graphite particles,
a mass ratio of the second covering material to the first covering material in a negative electrode mixture is higher than 1,
wherein coverage of the graphite particles with the first covering material ranges from 10% to 50%, and
wherein the second covering material is disposed on a surface of the first covering material.

2. The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1 , wherein a mass of the first covering material ranges from 0.1% to 5% of a mass of each of the graphite particles.

3. The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the covering layer has an average thickness in the range of 10 to 800 nm.

4. The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the first covering material contains a styrene-butadiene rubber, and the second covering material contains carboxymethyl cellulose.

5. The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1 , wherein a mass ratio of the silicon-containing particles to the graphite particles ranges from 1:99 to 20:80.

6. The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1 , wherein a mass of the second covering material ranges from 1% to 5% of a mass of each of the graphite particles.

7. The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1 , wherein that the covering layer has a thickness in the range of 10 to 400 nm.

Assignees

• Sanyo Electric Co

Inventors

• Wang Na
• Kasamatsu Shinji
• Kato Yoshio

Classifications

• H01M4/622

  being polymers · CPC title

• H01M4/133 Primary

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

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M2300/002

  Inorganic electrolyte · CPC title