Positive active material, positive electrode including the same, and lithium secondary battery including the positive electrode

Patent metadata

Field	Value
Publication number	US-2016156032-A1
Application number	US-201514707986-A
Country	US
Kind code	A1
Filing date	May 8, 2015
Priority date	Nov 28, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

Provided are a positive active material, a positive electrode including the same, and a lithium secondary battery including the positive electrode. The positive active material includes lithium cobalt oxide containing a metal element, and the lithium cobalt oxide containing a metal element has a ratio of a peak intensity of the O3 phase to a peak intensity of the H1-3 phase, I O3 /I H1-3 , that is greater than 1 in a X-ray diffraction (XRD) analysis spectrum using Cu-Kα radiation. Accordingly, a lithium secondary battery including the positive active material may have improved lifespan characteristics even at a high voltage.

First claim

1 . A positive active material for a lithium secondary battery, the positive active material comprising:
a lithium cobalt oxide containing a metal element, wherein the lithium cobalt oxide containing a metal element is represented by Formula 1:
Li a (Co 1.0-x-y Mg x Mn y )O 2   Formula 1

wherein, in Formula 1, 0.8≦a≦1.2, 0.0025≦x≦0.005, and 0.001≦y≦0.0075, wherein the lithium cobalt oxide containing a metal element has a ratio of a peak intensity of an O3 phase to a peak intensity of an H1-3 phase, I O3 /I H1-3 , that is greater than 1 in an X-ray diffraction (XRD) analysis spectrum using Cu-Kα radiation.

2 . The positive active material of claim 1 , wherein the I O3 /I H1-3 is greater than 1.0 and equal to or less than 5.0.

3 . The positive active material of claim 1 , wherein the metal element is placed in a site of the cobalt in a crystal lattice of the lithium cobalt oxide.

4 . The positive active material of claim 1 , wherein the lithium cobalt oxide containing a metal element does not comprise a spinel compound.

5 . The positive active material of claim 1 , wherein
the metal element is one or more elements selected from the group consisting of magnesium (Mg), manganese (Mn), nickel (Ni), aluminum (Al), titanium (Ti), calcium (Ca), iron (Fe), copper (Cu), and zinc (Zn).

6 . The positive active material of claim 1 , wherein the lithium cobalt oxide comprises two or more metal elements.

7 . The positive active material of claim 1 , wherein the metal element comprises Mg and Mn.

8 . The positive active material of claim 1 , wherein the metal element has an oxidation number of 2 or 3.

9 . (canceled)

10 . The positive active material of claim 1 , wherein
the lithium cobalt oxide containing a metal element is Li(CO 0.9965 Mg 0.0025 Mn 0.001 )O 2 , Li(CO 0.995 Mg 0.0025 Mn 0.0025 )O 2 , Li(CO 0.9925 Mg 0.0025 Mn 0.005 )O 2 , Li(Co 0.99 Mg 0.0025 Mn 0.0075 )O 2 , Li(CO 0.994 Mg 0.005 Mn 0.001 )O 2 , Li(CO 0.9925 Mg 0.005 Mn 0.0025 )O 2 , Li(Co 0.99 Mg 0.005 Mn 0.005 )O 2 , Li(CO 0.9875 Mg 0.005 Mn 0.0075 )O 2 , or a combination thereof.

11 . The positive active material of claim 1 , wherein
an average oxidation number N of a metal element contained in the lithium cobalt oxide is in a range of about 2.1 to about 2.75.

12 . The positive active material of claim 1 , wherein
a c-axis lattice parameter of a unit lattice of the lithium cobalt oxide containing a metal element is 14.050 Å or more.

13 . The positive active material of claim 1 , wherein
an average particle diameter D50 of the lithium cobalt oxide containing a metal element is in a range of about 1 μm to about 50 μm.

14 . A positive electrode for a lithium secondary battery, the positive electrode comprising:
the positive active material of any one of claim 1 .

15 . A lithium secondary battery comprising the positive electrode of claim 14 .

16 . The lithium secondary battery of claim 15 , wherein
a charging cutoff voltage of the lithium secondary battery is 4.5 V or more.

17 . The lithium secondary battery of claim 16 , wherein,
after charging, the lithium cobalt oxide containing a metal element in the positive electrode has a ratio of a peak intensity of the O3 phase to a peak intensity of the H1-3 phase, I O3 /I H1-3 , that is greater than 1 in an XRD analysis spectrum using Cu-Kα radiation.

18 . The lithium secondary battery of claim 16 , wherein,
the I O3 /I H1-3 is greater than 1.0 and equal to or less than 5.0.

19 . The lithium secondary battery of claim 16 , wherein,
the metal element is placed in a site of the cobalt in a crystal lattice of the lithium cobalt oxide.

20 . The lithium secondary battery of claim 16 , wherein, wherein
the metal element is one or more elements selected from the group consisting of magnesium (Mg), manganese (Mn), nickel (Ni), aluminum (Al), titanium (Ti), calcium (Ca), iron (Fe), copper (Cu), and zinc (Zn).

Assignees

• Samsung Sdi Co Ltd

Inventors

• Lee Daehoe
• Cho Sangwoo
• Park Sooyoun
• Kim Changwook
• Park Dohyung

Classifications

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/525 Primary

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

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• C01G51/66

  containing alkaline earth metals, e.g. SrCoO3 · CPC title