Cathode active material, positive electrode for lithium ion secondary battery, and lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-2016218358-A1
Application number	US-201514982530-A
Country	US
Kind code	A1
Filing date	Dec 29, 2015
Priority date	Jan 23, 2015
Publication date	Jul 28, 2016
Grant date	—

Abstract

A cathode active material for a positive electrode for a lithium ion secondary battery, comprising a lithium-containing composite oxide represented by aLi(Li 1/3 Mn 2/3 )O 2 ·(1-a)LiMO 2 (M: at least one transition metal element selected from Ni, Co and Mn, and 0<a<1), wherein in an X-ray diffraction pattern of the lithium-containing composite oxide, the ratio of the height (H 020 ) of a peak of (020) plane assigned to a crystal structure with space group C2/m to the height (H 003 ) of a peak of (003) plane assigned to a crystal structure with space group R-3m (i.e. H 020 /H 003 ) is at most 0.038, and the ratio of the height (H 110 ) of a peak of (110) plane assigned to a crystal structure with space group C2/m to the height (H 003 ) of a peak of (003) plane assigned to a crystal structure with space group R-3m (i.e. H 110 /H 003 ) is at most 0.013.

First claim

What is claimed is:

1 . A cathode active material comprising a lithium-containing composite oxide, wherein the lithium-containing composite oxide is represented by aLi(Li 1/3 Mn 2/3 )O 2 ·(1-a)LiMO 2 (wherein M is at least one transition metal element selected from Ni, Co and Mn, and a is more than 0 and less than 1), in an X-ray diffraction pattern of the lithium-containing composite oxide, the ratio of the height (H 020 ) of a peak of (020) plane assigned to a crystal structure with space group C2/m to the height (H 003 ) of a peak of (003) plane assigned to a crystal structure with space group R-3m (i.e. H 020 /H 003 ) is at most 0.038, and in an X-ray diffraction pattern of the lithium-containing composite oxide, the ratio of the height (H 110 ) of a peak of (110) plane assigned to a crystal structure with space group C2/m to the height (H 003 ) of a peak of (003) plane assigned to a crystal structure with space group R-3m (i.e. H 110 /H 003 ) is at most 0.013.

2 . The cathode active material according to claim 1 , wherein in the lithium-containing composite oxide, the ratio of the molar amount of Ni to the total molar amount (X) of Ni, Co and Mn (i.e. Ni/X) is from 0.15 to 0.45, the ratio of the molar amount of Co thereto (i.e. Co/X) is from 0 to 0.15, and the ratio of the molar amount of Mn thereto (i.e. Mn/X) is from 0.55 to 0.85.

3 . The cathode active material according to claim 1 , wherein the specific surface area of the cathode active material is from 0.5 to 4 m 2 /g.

4 . The cathode active material according to claim 1 , wherein the volume-based accumulative 50% size (D 50 ) of the cathode active material is from 3 to 15 μm.

5 . The cathode active material according to claim 1 , wherein in an X-ray diffraction pattern of the lithium-containing composite oxide, the crystallite diameter obtained by the Scherrer equation from a peak of (003) plane assigned to a crystal structure with space group R-3m is from 30 to 120 nm.

6 . The cathode active material according to claim 1 , wherein in an X-ray diffraction pattern of the lithium-containing composite oxide, the crystallite diameter obtained by the Scherrer equation from a peak of (110) plane assigned to a crystal structure with space group R-3m is from 10 to 80 nm.

7 . A positive electrode for a lithium ion secondary battery, which comprises the cathode active material as defined in claim 1 , an electrically conductive material and a binder.

8 . A lithium ion secondary battery, which comprises the positive electrode for a lithium ion secondary battery as defined in claim 7 , a negative electrode and a non-aqueous electrolyte.

Assignees

• Asahi Glass Co Ltd

Inventors

• Sakai Tomohiro
• Takasugi Tsubasa

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/131

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

• C01P2002/74

  by peak-intensities or a ratio thereof only · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title