Positive active material for rechargeable lithium battery, preparing method thereof and rechargeable lithium battery comprising positive electrode including positive active material

Patent metadata

Field	Value
Publication number	US-2021074998-A1
Application number	US-202017102332-A
Country	US
Kind code	A1
Filing date	Nov 23, 2020
Priority date	Dec 4, 2017
Publication date	Mar 11, 2021
Grant date	—

Abstract

A positive active material for a rechargeable lithium battery includes a first positive active material including a secondary particle including at least two agglomerated primary particles, where at least one part of the primary particles has a radial arrangement structure, as well as a second positive active material having a monolith structure, wherein the first and second positive active materials may each include nickel-based positive active materials and the surface of the second positive active material is coated with a boron-containing compound. Further embodiments provide a method of preparing the positive active material, and a rechargeable lithium battery including a positive electrode including the positive active material.

First claim

What is claimed is:

1 . A positive active material for a rechargeable lithium battery, comprising:
a first positive active material comprising a secondary particle comprising at least two agglomerated primary particles, where at least one part of the primary particles has a radial arrangement structure; and a second positive active material having a monolith structure, wherein the first positive active material and the second positive active material each comprise a nickel-based positive active material, and the surface of the second positive active material is coated with a boron-containing compound.

2 . The positive active material of claim 1 , wherein the boron-containing compound is boron oxide, lithium borate, or a combination thereof.

3 . The positive active material of claim 1 , wherein the boron-containing compound is B 2 O 3 , LiBO 2 , Li 3 B 7 O 12 , Li 6 B 4 O 9 , Li 3 B 11 O 18 , Li 2 B 4 O 7 , Li 3 BO 3 , or a combination thereof.

4 . The positive active material of claim 1 , wherein an amount of boron based on a total amount of the second positive active material is about 0.01 mol % to about 0.3 mol %.

5 . The positive active material of claim 1 , wherein an amount of the second positive active material is about 10 wt % to about 50 wt % based on a total weight of the positive active material.

6 . The positive active material of claim 1 , wherein the second positive active material has an average particle diameter of about 0.05 μm to about 10 μm.

7 . The positive active material of claim 1 , wherein in the first positive active material,
the secondary particle comprises a radial arrangement structure, or the secondary particle comprises an internal part comprising an irregular porous structure and an external part comprising the radial arrangement structure.

8 . The positive active material of claim 1 , wherein in the first positive active material,
the primary particles have a plate shape, and a long-axis of at least one part of the primary particles is arranged in a radial direction.

9 . The positive active material of claim 1 , wherein in the first positive active material, an average length of the primary particles is about 0.01 μm to about 5 μm.

10 . The positive active material of claim 1 , wherein in the first positive active material, an average particle diameter of the secondary particle is about 1 μm to about 20 μm.

11 . The positive active material of claim 1 , wherein the first positive active material is represented by Chemical Formula 1:
Li a (Ni 1-x-y-z Co x Mn y M z )O 2 , and  Chemical Formula 1
wherein, in Chemical Formula 1, M is an element selected from boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zirconium (Zr), and aluminum (Al), and 0.95≤a≤1.3, x≤(1-x-y-z), y≤(1-x-y-z), 0<x<1, 0≤y<1, and 0≤z<1.

12 . The positive active material of claim 1 , wherein the second positive active material is represented by Chemical Formula 1:
Li a (Ni 1-x-y-z Co x Mn y M z )O 2 , and  Chemical Formula 1
wherein, in Chemical Formula 1, M is an element selected from boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zirconium (Zr), and aluminum (Al), and 0.95≤a≤1.3, x≤(1-x-y-z), y≤(1-x-y-z), 0<x<1, 0≤y<1, and 0≤z<1.

13 . A method of preparing a positive active material for a rechargeable lithium battery, the method comprising:
subjecting a first precursor to a first heat-treatment in a first oxidizing gas atmosphere to obtain a first nickel-based oxide; subjecting a second precursor to a second heat-treatment in a second oxidizing gas atmosphere to obtain a second nickel-based oxide having a monolith structure; mixing the second nickel-based oxide and a boron-containing precursor and subjecting the mixture to a third heat-treatment to obtain the second nickel-based oxide coated with a boron-containing compound; and mixing the first nickel-based oxide and the second nickel-based oxide coated with the boron-containing compound to obtain a positive active material comprising a first positive active material and a second positive active material having a monolith structure and coated with the boron-containing compound.

14 . The method of claim 13 , wherein the boron-containing precursor is H 3 BO 3 , B 2 O 3 , C 6 H 5 B(OH) 2 , (C 6 H 5 O) 3 B, [CH 3 (CH 2 ) 3 O] 3 B, C 13 H 19 BO 3 , C 3 H 9 B 3 O 6 , (C 3 H 7 O) 3 B, or a combination thereof.

15 . The method of claim 13 , wherein an amount of the boron-containing precursor based on 100 parts by weight of the second nickel-based oxide is about 0.01 parts by weight to about 0.35 parts by weight.

16 . The method of claim 13 , wherein a temperature for the third heat-treatment for the mixture of the second nickel-based oxide and the boron-containing precursor is about 300° C. to 500° C.

17 . The method of claim 13 , wherein the obtaining of the second nickel-based oxide comprises pulverizing a material obtained from subjecting the second precursor to the second heat-treatment to obtain particles having a monolith structure.

18 . The method of claim 13 , wherein the second precursor is obtained by mixing a second composite metal hydroxide having a specific surface area of about 1 m 2 /g to about 30 m 2 /g, as measured utilizing a BET method, with a lithium-based material.

19 . The method of claim 13 , wherein a mixing ratio of the first nickel-based oxide and the second nickel-based oxide coated with the boron-containing compound is about 9:1 to about 5:5 based on a weight ratio.

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

Assignees

• Samsung Sdi Co Ltd

Inventors

• Yun Pilsang
• Kim Jongmin

Classifications

• C01G53/82

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

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/366

  as layered products · CPC title

• C01G53/42

  containing alkali metals, e.g. LiNiO2 · CPC title

• C01P2006/40

  Electric properties · CPC title