Positive active material for rechargeable lithium battery, method of preparing the same and rechargeable lithium battery including the same

Patent metadata

Field	Value
Publication number	US-2020295368-A1
Application number	US-202016817163-A
Country	US
Kind code	A1
Filing date	Mar 12, 2020
Priority date	Mar 15, 2019
Publication date	Sep 17, 2020
Grant date	—

Abstract

A positive active material for a rechargeable lithium battery includes nickel-based lithium transition metal oxide secondary particles, in which a plurality of primary particles are aggregated. The primary particles include polycrystalline primary particles composed of 2 to 10 single crystals, and each of the single crystals has a particle diameter of about 0.5 μm to about 3 μm.

First claim

What is claimed is:

1 . A positive active material for a rechargeable lithium battery, the positive active material comprising:
nickel-based lithium transition metal oxide secondary particles in which a plurality of primary particles are aggregated, wherein the primary particles each comprise polycrystalline primary particles composed of 2 to 10 single crystals, and each of the single crystals has a particle diameter of about 0.5 μm to about 3 μm.

2 . The positive active material of claim 1 , wherein the polycrystalline primary particles are about 30% or more of the total number of primary particles.

3 . The positive active material of claim 1 , wherein the primary particle has a particle diameter of about 2 μm to about 5 μm.

4 . The positive active material of claim 1 , wherein the secondary particle has a particle diameter of about 10 μm to about 40 μm.

5 . The positive active material of claim 1 , wherein a peak intensity ratio I(003)/I(101) measured by X-ray diffraction analysis of the positive active material is about 9 to about 11.

6 . The positive active material of claim 1 , wherein a peak intensity ratio I(003)/I(104) measured by X-ray diffraction analysis of the positive active material is about 1.6 to about 2.0, and
a peak intensity ratio I(003)/I(104) measured by X-ray diffraction analysis of an electrode plate comprising the positive active material is about 3.8 to about 4.5.

7 . The positive active material of claim 1 , wherein the nickel-based lithium transition metal oxide is represented by Chemical Formula 1:
Li x Ni 1−a−b−c CO a Mn b McO 2   Chemical Formula 1
wherein, in Chemical Formula 1, 0.9≤x≤1.2, 0<a≤0.4, 0≤b≤0.4, 0≤c≤0.1, and M is at least one element selected from Mg, Ca, Sr, Ba, Ti, Zr, Nb, Mo, W, Zn, Al, Si, Cr, Fe, V, and a rare earth element.

8 . The positive active material of claim 1 , wherein the nickel-based lithium transition metal oxide comprises LiNi 0.9 Co 0.08 Al 0.02 O 2 , LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , Li 1.01 Ni 0.8 Co 0.1 Mn 0.1 O 2 , or a combination thereof.

9 . A method of preparing the positive active material of claim 1 , the method comprising:
mixing an aqueous solution comprising a nickel compound and a cobalt compound with a basic solution; performing a co-precipitation reaction to prepare a resultant; drying the resultant to prepare a transition metal precursor; mixing the transition metal precursor, a lithium compound, and an inert surfactant; and performing a heat-treatment.

10 . The method of claim 9 , wherein the transition metal precursor has a tap density of greater than about 2.0 g/cm 3 and less than or equal to about 2.5 g/cm 3 .

11 . The method of claim 9 , wherein the transition metal precursor is a compound represented by Chemical Formula 2, Chemical Formula 3, or a combination thereof:
Li x Ni 1−a−b−c Co a Mn b M c (OH) 2   Chemical Formula 2
Li x Ni 1−a−b−c Co a Mn b M c O,   Chemical Formula 3
wherein, in Chemical Formula 2 and Chemical Formula 3, 0.9≤x≤1.2, 0<a≤0.4, 0≤c0.1, and M is at least one element selected from Mg, Ca, Sr, Ba, Ti, Zr, Nb, Mo, W, Zn, Al, Si, Cr, Fe, V, and a rare earth element.

12 . The method of claim 9 , wherein the transition metal precursor and the lithium compound are mixed so that a Li/metal (transition metals excluding Li) mole ratio is greater than about 1.0 and less than about 1.1.

13 . The method of claim 9 , wherein the lithium compound is lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate, or a combination thereof.

14 . The method of claim 9 , wherein the inert surfactant is in an amount of less than or equal to about 1 part by weight based on 100 parts by weight of the transition metal precursor.

15 . The method of claim 9 , wherein the heat-treatment is maintained for about 15 hours to about 25 hours at a temperature of greater than about 800° C. and less than 900° C.

16 . A rechargeable lithium battery comprising:
a positive electrode comprising the positive active material of claim 1 ; a negative electrode comprising a negative active material; and an electrolyte.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kong Youngsun
• Ahn Kiyong
• Kim Jinyoung
• Choo Sung Ho
• Kwon Seonyoung

Classifications

• C01G53/82

  Compounds containing nickel, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• H01M10/052

  Li-accumulators · CPC title

• C01G53/50 Primary

  of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2 · CPC title

• C01P2002/74

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

• C01P2004/50

  Agglomerated particles · CPC title