Cathode active material, cathode and nonaqueous secondary battery

Patent metadata

Field	Value
Publication number	US-9337489-B2
Application number	US-201514628715-A
Country	US
Kind code	B2
Filing date	Feb 23, 2015
Priority date	May 22, 2009
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

A cathode active material of the present invention is a cathode active material having a composition represented by General Formula (1) below,

LiFe 1−x M x P 1−y Si y O 4   (1),
where: an average valence of Fe is +2 or more; M is an element having a valence of +2 or more and is at least one type of element selected from the group consisting of Zr, Sn, Y, and Al; the valence of M is different from the average valence of Fe; 0<x≦0.5; and y=x×({valence of M}−2)+(1−x)×({average valence of Fe}−2). This provides a cathode active material that not only excels in terms of safety and cost but also can provide a long-life battery.

First claim

What is claimed is:

1. A cathode active material consisting of a composition represented by General Formula (1) below,
LiFe 1−x M x P 1−y Si y O 4   (1),

where:
an average valence of Fe is +2 or more, the average valence of Fe being an average of valences of all Fe atoms constituting the cathode active material;
Fe takes on a valence of +2 or +3;
M has a valence of +2 or more, and M is at least one type of element selected from the group consisting of Zr, Sn, Y, and Al;
the valence of M is different from the average valence of Fe;
0 <x≦0.5; and
y =x×({valence of M}−2)+(1−x)×({average valence of Fe}−2).

2. The cathode active material according to claim 1 ,
wherein:
Fe has a ratio of Fe 2+ :Fe 3+ =95:5 to 100:0 as determined on a basis of an area ratio of a Mössbauer spectrum.

3. The cathode active material according to claim 1 ,
wherein:
M is Zr; and
a substitution amount x on Fe site is 0.25 or less.

4. The cathode active material according to claim 1 ,
wherein:
M is Zr; and
a substitution amount x on Fe site is 0.05≦x≦0.15.

Assignees

• Sharp Kk

Inventors

• Ohira Koji
• Nishijima Motoaki
• Sueki Toshitsugu
• Esaki Shogo
• Tanaka Isao
• Koyama Yukinori
• Tanaka Katsuhisa
• Fujita Koji
• Murai Shunsuke

Classifications

• H01M4/5825 Primary

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M10/0481

  Compression means other than compression means for stacks of electrodes and separators · CPC title

• H01M4/136 Primary

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• Y02P20/133

  Renewable energy sources, e.g. sunlight · CPC title

• H01M10/052

  Li-accumulators · CPC title