Non-aqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-11923528-B2
Application number	US-201716471944-A
Country	US
Kind code	B2
Filing date	Dec 20, 2017
Priority date	Dec 28, 2016
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

A positive electrode, a negative electrode, and a non-aqueous electrolyte. The negative electrode includes a negative electrode material, a binder, and a thickener, and the negative electrode material includes a lithium silicate phase, and Si particles dispersed in the lithium silicate phase. The ratio of the Si particles in the negative electrode material is 30 mass % or more. The binder includes a poly(meth)acrylic acid, the thickener includes a carboxyalkyl cellulose, and the amount of the poly(meth)acrylic acid relative to 100 parts by mass of the negative electrode material is 0.1 parts by mass or more and 5 parts by mass or less. The non-aqueous electrolyte includes a lithium salt, a non-aqueous solvent, and an acid that exhibits a pKa of 1 to 30 in water at 25° C. The non-aqueous electrolyte secondary battery can suppress the generation of gas during high-temperature storage, and secure excellent cycle characteristics.

First claim

The invention claimed is:

1. A non-aqueous electrolyte secondary battery comprising: a positive electrode capable of electrochemically absorbing and desorbing lithium, a negative electrode capable of electrochemically absorbing and desorbing lithium; and a non-aqueous electrolyte,
wherein the negative electrode includes a negative electrode material, a binder, and a thickener,
the negative electrode material includes an LSX particle including a lithium silicate phase, and silicon particles dispersed in the lithium silicate phase,
a ratio of the silicon particles in the LSX particle is 30 mass % or more,
the binder includes a poly(meth)acrylic acid alkali metal salt,
the thickener includes a carboxyalkyl cellulose,
an amount of the poly(meth)acrylic acid alkali metal salt relative to 100 parts by mass of the negative electrode material is 0.1 parts by mass or more and 5 parts by mass or less, and
the non-aqueous electrolyte includes a lithium salt, a non-aqueous solvent that dissolves the lithium salt, and an acid that exhibits a pKa of 1 to 30 in water at 25 ° C.,
wherein a concentration of the acid in the non-aqueous electrolyte is 0.01 to less than 0.05 mass %, wherein the concentration of the acid in the non-aqueous electrolyte exists at least in an initial state of the battery,
wherein the acid includes polycarboxylic acid, and
wherein the polycarboxylic acid is selected from malonic acid, oxalic acid, fumaric acid, phthalic acid, or combinations thereof.

2. The non-aqueous electrolyte secondary battery according to claim 1 ,
wherein the acid has a pKa of 1 to 20.

3. The non-aqueous electrolyte secondary battery according to claim 1 ,
wherein an amount of the carboxyalkyl cellulose relative to 100 parts by mass of the negative electrode material is 1 part by mass or more and 5 parts by mass or less.

4. The non-aqueous electrolyte secondary battery according to claim 1 ,
wherein an amount of the poly(meth)acrylic acid alkali metal salt relative to 100 parts by mass of the carboxyalkyl cellulose is 10 parts by mass or more and 150 parts by mass or less.

5. The non-aqueous electrolyte secondary battery according to claim 1 ,
wherein a ratio of the silicon particles in the negative electrode material is 80 mass % or less.

6. The non-aqueous electrolyte secondary battery according to claim 1 ,
wherein a composition of the lithium silicate phase is represented by the formula: Li 2 O·xSiO 2 , and satisfies 0.5≤x≤20.

7. The non-aqueous electrolyte secondary battery according to claim 1 ,
wherein the carboxyalkyl cellulose is carboxy C 1-2 alkyl cellulose or a salt thereof.

8. The non-aqueous electrolyte secondary battery according to claim 1 ,
wherein the negative electrode further includes a carbon material that electrochemically absorbs and desorbs lithium, and
a ratio of the negative electrode material to a total of the negative electrode material and the carbon material is 0.1 mass % or more and 30 mass % or less.

9. The non-aqueous electrolyte secondary battery according to claim 1 ,
wherein the lithium silicate phase includes Li 2 O·0.5SiO 2.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Nishitani Satoshi
• Minami Hiroshi
• Deguchi Masaki

Classifications

• H01M4/131 Primary

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

• H01M4/133

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

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/364

  as mixtures · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title