Cathode active material for lithium-ion secondary batteries, method for producing same, and lithium-ion secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-10468673-B2
Application number	US-201515540519-A
Country	US
Kind code	B2
Filing date	Aug 21, 2015
Priority date	Dec 30, 2014
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

Provided are a positive active material for a lithium secondary battery, a method of preparing the positive active material, and a lithium ion secondary battery including the positive active material, the positive active material including a lithium-containing compound represented by the formula of Li2−xM′O3−y (wherein M′ is at least one element selected from Mg, Al, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Y, Zr, Nb, Mo, Ru, and F; 0≤x≤1; and 0≤y≤3) on a surface or inside of a lithium metal oxide represented by the formula of Li1−xNiyM1−yO2−z (wherein M is at least one element selected from Co and Mn; 0≤x≤0.05; 0.6≤y≤1; and 0≤z≤0.05).

First claim

The invention claimed is:

1. A method of preparing a positive active material for a lithium secondary battery, the method comprising:
coating a lithium metal oxide represented by Formula 1 and having a layered structure with at least one coating material selected from a metal oxide and a fluorine-containing compound by stirring the lithium metal oxide and the at least one coating material at about 8,000 rpm to about 20,000 rpm; and
thermally treating at about 800° C. to 1,000° C. a resulting powder from the coating step to form a lithium-containing compound represented by Formula 2 on the surface or inside of the lithium metal oxide:
Li 1−x Ni y M 1−y O 2−z   [Formula 1]

wherein, in Formula 1, M is at least one element selected from Co and Mn; 0≤x≤0.05; 0.6≤y≤1; and 0≤z≤0.05, and
Li 2−x M′O 3−y   [Formula 2]

wherein, in Formula 2, M′ is at least one element selected from Mg, Al, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Y, Zr, Nb, Mo, Ru, and F; 0≤x≤1; and 0≤y≤3.

2. The method of claim 1 , wherein, in the coating of the lithium metal oxide, the stirring is performed for about 10 seconds to about 60 seconds.

3. The method of claim 1 , wherein the coating is performed by dry coating.

4. The method of claim 1 , wherein, in the thermal treating, the at least one coating material reacts with a residual lithium on the surface or inside of the lithium metal oxide, thereby to form the lithium-containing compound represented by Formula 2 on the surface or inside of the lithium metal oxide.

5. The method of claim 4 , wherein an amount of the residual lithium after the thermal treating is reduced by about 10% to about 20%, compared to that when the lithium metal oxide represented by Formula 1 is heated alone.

6. The method of claim 1 , wherein the metal oxide is an oxide including at least one metal element selected from the group consisting of Mg, Al, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Y, Zr, Nb, Mo, and Ru.

7. The method of claim 1 , wherein the metal oxide is at least one selected from the group consisting of MgO, Al 2 O 3 , CaO, TiO 2 , V 2 O 5 , Cr 2 O 3 , Fe 2 O 3 , CuO, ZnO, Ga 2 O 3 , SrO, Y 2 O 3 , ZrO 2 , NbO 2 , MoO 3 , and RuO 2 .

8. The method of claim 1 , wherein the fluorine-containing compound is at least one selected from the group consisting of NaF, NH 3 F, and PVDF.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Ji Yoon
• Chang Dong Gyu
• Kim Jong Min
• Lee Mi Sun
• Chae Young Joo

Classifications

• H01M10/052

  Li-accumulators · 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

• H01M4/485

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

• H01M4/366 Primary

  as layered products · CPC title

• H01M2004/021

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