Positive electrode active material for lithium secondary battery, positive electrode for lithium secondary battery, and lithium secondary battery

Patent metadata

Field	Value
Publication number	US-2017237069-A1
Application number	US-201515518471-A
Country	US
Kind code	A1
Filing date	Oct 13, 2015
Priority date	Oct 15, 2014
Publication date	Aug 17, 2017
Grant date	—

Abstract

A positive electrode active material, which has a crystallite size α/crystallite size β ratio (α/β) of 1 to 1.75 or less, wherein the crystallite size α is within a peak region of 2θ=18.7±1° and the crystallite size β is within a peak region of 2θ=44.6±1°, each determined by a powder X-ray diffraction measurement using Cu-Kα ray, and has a composition represented by formula (I) below:
Li[Li x (Ni a Co b Mn c M d ) 1-x ]O 2   (I)

wherein 0≦x≦0.2, 0.3<a<0.7, 0<b<0.4, 0<c<0.4, 0≦d<0.1, a+b+c+d=1, and M is at least one metal selected from the group consisting of Fe, Cr, Ti, Mg, Al and Zr.

First claim

1 . A positive electrode active material, which has a crystallite size α/crystallite size β ratio (α/β) of 1 to 1.75 or less, wherein the crystallite size α is within a peak region of 2θ=18.7±1° and the crystallite size β is within a peak region of 2θ=44.6±1°, each determined by a powder X-ray diffraction measurement using Cu-Kα ray, and has a composition represented by formula (I) below:
Li[Li x (Ni a Co b Mn c M d ) 1-x ]O 2   (I)

wherein 0≦x≦0.2, 0.3<a<0.7, 0<b<0.4, 0<c<0.4, 0≦d<0.1, a+b+c+d=1, and M is at least one metal selected from the group consisting of Fe, Cr, Ti, Mg, Al and Zr.

2 . The positive electrode active material according to claim 1 , wherein a, b and c in the formula (I) satisfy the following relationship: a≧b+c.

3 . The positive electrode active material according to claim 1 , wherein the crystallite size α/crystallite size β ratio (α/β) is 1 to 1.5.

4 . The positive electrode active material according to claim 1 , which has a BET specific surface area of 0.5 m 2 /g to 4 m 2 /g.

5 . The positive electrode active material according to claim 1 , wherein the crystallite size β is 150 Å to 650 Å.

6 . The positive electrode active material according to claim 1 , wherein the average primary particle diameter is 0.05 μm to 1 μm, and the volume-based 50% cumulative particle size D 50 is 1 μm to 10 μm.

7 . The positive electrode active material according to claim 1 , wherein the ratio (D 90 /D 10 ) of volume-based 90% cumulative particle size D 90 to volume-based 10% cumulative particle size D 10 is in the range of from 2.0 to 3.5.

8 . The positive electrode active material according to claim 1 , which has a tapped bulk density of 1.2 to 2.0.

9 . A positive electrode for a lithium secondary battery, comprising the positive electrode active material of claim 1 .

10 . A lithium secondary battery, comprising the positive electrode of claim 9 .

Assignees

• Sumitomo Chemical Co
• Tanaka Chemical Corp

Inventors

• Takamori Kenji
• Kurita Hiroyuki
• Imanari Yuichiro
• Yamashita Daisuke
• Nakao Kimiyasu
• Doumae Kyousuke

Classifications

• C01G53/00

  Compounds of nickel · CPC title

• C01P2006/40

  Electric properties · CPC title

• C01P2004/54

  Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension · CPC title

• C01P2006/11

  Powder tap density · CPC title

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title