Negative electrode active material for lithium ion secondary battery, negative electrode for lithium ion secondary battery, and lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-9728782-B2
Application number	US-201514693143-A
Country	US
Kind code	B2
Filing date	Apr 22, 2015
Priority date	Apr 25, 2014
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A negative electrode active material for a lithium ion secondary battery includes a network structure formed by at least some of iron oxide particles being linked to each other.

First claim

What is claimed is:

1. A negative electrode active material for a lithium ion secondary battery, comprising a network structure formed by at least some of iron oxide particles being linked to each other, thereby forming an iron oxide wire, wherein
in the network structure, a ratio of an average network pore diameter to the average iron oxide wire diameter (average network pore diameter/average iron oxide wire diameter) is 0.2 or more,
the iron oxide has an average iron oxide wire diameter of 192 nm or less, and
the average iron oxide wire diameter is defined as an average diameter of said iron oxide particles linked to each other.

2. A negative electrode for a lithium ion secondary battery, comprising:
the negative electrode active material according to claim 1 ; and
Ketjen black as a conductive auxiliary agent.

3. A lithium ion secondary battery comprising:
the negative electrode according to claim 2 ;
a positive electrode; and
a nonaqueous electrolyte.

4. The negative electrode active material for a lithium ion secondary battery according to claim 1 , wherein the iron oxide is Fe 2 O 3 .

5. The negative electrode active material for a lithium ion secondary battery according to claim 1 , wherein the iron oxide is α-Fe 2 O 3 .

6. The negative electrode active material for a lithium ion secondary battery according to claim 1 , wherein the iron oxide has an average iron oxide wire diameter of 98 nm or less.

7. The negative electrode active material for a lithium ion secondary battery according to claim 1 , wherein the ratio is from 0.2 to 20.

8. The negative electrode active material for a lithium ion secondary battery according to claim 1 , wherein the negative electrode active material comprises 60% or more of the network structure.

9. The negative electrode active material for a lithium ion secondary battery according to claim 1 , wherein the iron oxide particles forming the network structure have a primary particle diameter of from 10 nm to 100 nm.

Assignees

• Tdk Corp

Inventors

• Kawanaka Yasuyuki
• Kato Tomohiko
• Sano Atsushi

Classifications

• H01M50/489

  Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties · CPC title

• H01M10/0568

  characterised by the solutes · CPC title

• H01M4/1391

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

• H01M4/625

  Carbon or graphite · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title