Positive electrode active material and method for preparing the same

Patent metadata

Field	Value
Publication number	US-2022045320-A1
Application number	US-202016988024-A
Country	US
Kind code	A1
Filing date	Aug 7, 2020
Priority date	Aug 7, 2020
Publication date	Feb 10, 2022
Grant date	—

Abstract

A method for preparing a positive electrode active material and a positive electrode active material prepared thereby are provided. The method includes a first step of reacting a coating precursor preparation solution including a metal solution containing metal ions included in a coating layer and a chelating agent to prepare a coating precursor, which is a complex in which the metal ions and the chelating agent are combined, and a second step of dry-mixing particles having a specific composition and the coating precursor, followed by firing the mixture to form a coating layer having a specific composition on surfaces of the particles.

First claim

1 . A method for preparing a positive electrode active material comprising:
reacting a coating precursor preparation solution comprising a metal solution containing metal ions and a chelating agent to prepare a coating precursor, wherein the coating precursor is a complex in which the metal ions and the chelating agent are combined; and dry-mixing particles having the composition of Formula 1 or Formula 2 below and the coating precursor to obtain a mixture, followed by firing the mixture to form a coating layer having the composition of Formula 3 below on surfaces of the particles:
Li[Co 1-a M 1 a ]O 2   [Formula 1]

wherein, in Formula 1 above, M 1 is one or more selected from the group consisting of B, Mg, Ca, Al, Ti, V, Cr, Fe, Zn, Ga, Y, Zr, Nb, Mo, Ta, and W, and 0≤a<0.1,
Li[Ni b Co c Mn d M 2 e ]O 2   [Formula 2]

wherein, in Formula 2 above, M 2 is one or more selected from the group consisting of B, Mg, Ca, Al, Ti, V, Cr, Fe, Zn, Ga, Y, Zr, Nb, Mo, Ta, and W, and 0.8≤b<1, 0<c<0.2, 0<d<0.2, 0≤e<0.1, and b+c+d+e=1,
Li[Ni f Co g Mn h M 3 i ]O 2   [Formula 3]

wherein, in Formula 3 above, M 3 is one or more selected from the group consisting of B, Mg, Ca, Al, Ti, V, Cr, Fe, Zn, Ga, Y, Zr, Nb, Mo, Ta, and W, and 0<f≤0.4, 0≤g≤0.6, 0≤h≤0.6, 0≤i<0.1, and f+g+h+i=1.

2 . The method of claim 1 , wherein the chelating agent is a Lewis acid compound including a carboxylic acid group or a nitrogen element.

3 . The method of claim 2 , wherein the chelating agent is one or more selected from the group consisting of citric acid, polyvinylpyrrolidone, and glycolic acid.

4 . The method of claim 1 , wherein the coating precursor preparation solution is prepared by adding the metal solution containing ions and the chelating agent to a solvent, followed by mixing.

5 . The method of claim 4 , wherein the solvent is one or more selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 2,3-butanediol.

6 . The method of claim 1 , wherein the average particle diameter (D 50 ) of the coating precursor is 1 nm to 500 nm.

7 . The method of claim 1 , wherein the reacting the coating precursor preparation solution is performed at 200° C. to 300° C.

8 . The method of claim 1 , wherein the firing is performed at a temperature 800° C. to 900° C.

9 . The method of claim 8 , wherein the firing is performed after raising the temperature to 800° C. to 900° C. at a rate of 5° C./min to 10° C./min.

10 . A positive electrode active material comprising:
particles having the composition of Formula 1 or Formula 2 below; and a coating layer formed on surfaces of the particles and having the composition of Formula 3 below:
Li[Co 1-a M 1 a ]O 2   [Formula 1]

wherein, in Formula 1 above, M 1 is one or more selected from the group consisting of B, Mg, Ca, Al, Ti, V, Cr, Fe, Zn, Ga, Y, Zr, Nb, Mo, Ta, and W, and 0≤a<0.1,
Li[Ni b Co c Mn d M 2 e ]O 2   [Formula 2]

wherein, in Formula 2 above, M 2 is one or more selected from the group consisting of B, Mg, Ca, Al, Ti, V, Cr, Fe, Zn, Ga, Y, Zr, Nb, Mo, Ta, and W, and 0.8≤b<1, 0<c<0.2, 0<d<0.2, 0≤e<0.1, and b+c+d+e=1,
Li[Ni f Co g Mn h M 3 i ]O 2   [Formula 3]

wherein, in Formula 3 above, M 3 is one or more selected from the group consisting of B, Mg, Ca, Al, Ti, V, Cr, Fe, Zn, Ga, Y, Zr, Nb, Mo, Ta, and W, and 0<f<0.4, 0≤g≤0.6, 0≤h≤0.6, 0≤i<0.1, and f+g+h+i=1.

11 . The positive electrode active material of claim 10 , wherein the surfaces of the particles are completely surrounded by the coating layer.

12 . The positive electrode active material of claim 10 , wherein the thickness of the coating layer is 1 nm to 500 nm.

13 . A positive electrode for a lithium secondary battery, the positive electrode comprising the positive electrode active material according to claim 10 .

14 . A lithium secondary battery comprising the positive electrode for a lithium secondary battery according to claim 13 .

Assignees

• Lg Chemical Ltd
• Univ California

Inventors

• Jo Chi Ho
• Jung Wang Mo
• Chung Hyeseung
• Meng Ying Shirley

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/505

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

• H01M4/131

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