Positive Electrode Active Material, Method of Preparing the Positive Electrode Active Material, and Positive Electrode and Lithium Secondary Battery Which Include the Positive Electrode Active Material

Patent metadata

Field	Value
Publication number	US-2022013775-A1
Application number	US-202017413100-A
Country	US
Kind code	A1
Filing date	Jan 7, 2020
Priority date	Jan 7, 2019
Publication date	Jan 13, 2022
Grant date	—

Abstract

A positive electrode active material includes a nickel-based lithium transition metal oxide containing nickel in an amount of 60 mol % or more based on a total number of moles of metals excluding lithium, wherein cobalt is included in an amount of greater than 0 ppm to 6,000 ppm or less on a surface of the nickel-based lithium transition metal oxide. A method of preparing the positive electrode active material, a positive electrode for a lithium secondary battery and a lithium secondary battery which includes the positive electrode active material are also provided.

First claim

1 . A positive electrode active material comprising:
a nickel-based lithium transition metal oxide containing nickel in an amount of 60 mol % or more based on a total number of moles of metals excluding lithium; and a cobalt, wherein the cobalt is included in an amount of greater than 0 ppm to 6,000 ppm or less on a surface of the nickel-based lithium transition metal oxide.

2 . The positive electrode active material of claim 1 , wherein the cobalt is included in an amount of 2,000 ppm to 5,000 ppm.

3 . The positive electrode active material of claim 1 , wherein the cobalt has a concentration gradient from a surface of a positive electrode active material particle, and wherein the amount of the cobalt is decreased in a direction toward a center of the positive electrode active material particle.

4 . The positive electrode active material of claim 1 , wherein the cobalt is present within 2,000 nm from the surface of the positive electrode active material particle in the direction toward the center of the positive electrode active material particle.

5 . The positive electrode active material of claim 1 , wherein the nickel-based lithium transition metal oxide is represented by Formula 1:
Li 1+a [Ni x Mn y M 1 z ]O 2   [Formula 1]
wherein, in Formula 1, M 1 is at least one metallic element selected from the group consisting of Al, Mg, Ti, Nb, W, Sc, Zr, Si, V, Fe, Y, and Mo, 0≤a≤0.3, 0.60≤x<1, 0<y≤0.40, and 0≤z≤0.35.

6 . A method of preparing a positive electrode active material, comprising:
preparing a transition metal hydroxide which contains nickel in an amount of 60 mol % or more based on a total number of moles of transition metals and does not contain cobalt; mixing the transition metal hydroxide and a lithium raw material and sintering the mixture; and mixing a cobalt raw material in an amount such that an amount of the cobalt in a finally prepared positive electrode active material is in a range of greater than 0 ppm to 6,000 ppm or less in the mixing of the transition metal hydroxide and the lithium raw material and the sintering of the mixture, or after the sintering.

7 . The method of claim 6 , wherein the transition metal hydroxide is represented by Formula 2:
Ni x1 Mn y1 M 1 z1 (OH) 2   [Formula 2]
wherein, in Formula 2, M 1 is at least one metallic element selected from the group consisting of Al, Mg, Ti, Nb, W, Sc, Zr, Si, V, Fe, Y, and Mo, 0.60≤x1<1, 0<y1≤0.40, and 0≤z1≤0.35.

8 . The method of claim 6 , wherein the cobalt raw material is mixed in an amount such that the amount of the cobalt in the finally prepared positive electrode active material is in a range of 2,000 ppm to 5,000 ppm.

9 . A method of preparing a positive electrode active material, comprising:
preparing a transition metal aqueous solution containing a nickel raw material and a cobalt raw material; preparing a transition metal hydroxide by a co-precipitation reaction of the transition metal aqueous solution; and mixing the transition metal hydroxide and a lithium raw material and sintering the mixture, wherein the nickel raw material is included in an amount such that an atomic ratio of nickel is 60 mol % or more based on a total number of moles of transition metals in the transition metal aqueous solution, and the cobalt raw material is mixed in an amount such that an amount of cobalt in a finally prepared positive electrode active material is in a range of greater than 0 ppm to 6,000 ppm or less.

10 . The method of claim 9 , wherein the cobalt raw material is mixed in the amount such that the amount of the cobalt in the finally prepared positive electrode active material is in a range of 2,000 ppm to 5,000 ppm.

11 . A positive electrode comprising:
a positive electrode collector, and a positive electrode active material layer formed on the positive electrode collector, wherein the positive electrode active material layer comprises the positive electrode active material of claim 1 .

12 . A lithium secondary battery comprising the positive electrode of claim 11 .

Assignees

• Lg Chemical Ltd

Inventors

• Lee Dong Hun
• Park Sung Bin
• Cho Hyung Man
• Han Jung Min
• Hwang Jin Tae
• Jung Wang Mo

Classifications

• 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

• C01P2006/80

  Compositional purity · CPC title

• H01M4/131

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

• H01M2004/028

  Positive electrodes · CPC title

• C01P2002/85

  by XPS, EDX or EDAX data · CPC title