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-2019173076-A1
Application number	US-201816209659-A
Country	US
Kind code	A1
Filing date	Dec 4, 2018
Priority date	Dec 4, 2017
Publication date	Jun 6, 2019
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. The first and second positive active materials may both include nickel-based positive active materials. A method of preparing the positive active material, and a rechargeable lithium battery including a positive electrode including the positive active material are also provided.

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, at least one part of the primary particles having a radial arrangement structure; and a second positive active material having a monolith structure, wherein both of the first positive active material and the second positive active material comprise a nickel-based positive active material.

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

3 . The positive active material of claim 1 , wherein:
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 a radial arrangement structure.

4 . The positive active material of claim 1 , wherein 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.

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

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

7 . The positive active material of claim 1 , wherein a residual lithium concentration in the positive active material is less than or equal to about 1200 ppm.

8 . 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 ,  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), 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.

9 . 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   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), 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.

10 . A method of preparing a positive active material for a rechargeable lithium battery, comprising:
subjecting a first precursor to a first heat-treatment in an oxidizing gas atmosphere to obtain a first nickel-based oxide, subjecting a second precursor to a second heat-treatment in an oxidizing gas atmosphere to obtain a second nickel-based oxide, mixing the first nickel-based oxide and the second nickel-based oxide to yield a mixture, and subjecting the mixture to a third heat-treatment in an oxidizing gas atmosphere to obtain a positive active material comprising a first positive active material and a second positive active material, wherein the second nickel-based oxide comprises particles having a monolith structure.

11 . The method of claim 10 , wherein obtaining the second nickel-based oxide comprises pulverizing a resulting material obtained after subjecting the second precursor to the second heat-treatment in an oxidizing gas atmosphere, the particles having a monolith structure.

12 . The method of claim 10 , 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 using a BET method, with a lithium-based material.

13 . The method of claim 10 , wherein a mixing ratio of the first nickel-based oxide and the second nickel-based oxide is about 9:1 to about 5:5 based on a weight ratio.

14 . 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.

15 . The rechargeable lithium battery of claim 14 , wherein the second positive active material is included in an amount of about 10 wt % to about 50 wt % based on a total weight of the positive active material.

16 . The rechargeable lithium battery of claim 14 , wherein:
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 a radial arrangement structure.

17 . The rechargeable lithium battery of claim 14 , wherein 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.

18 . The rechargeable lithium battery of claim 14 , wherein a residual lithium concentration in the positive active material is less than or equal to about 1200 ppm.

19 . The rechargeable lithium battery of claim 14 , 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 ,  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), 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.

20 . The rechargeable lithium battery of claim 14 , 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   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), 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.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Jongmin
• Kim Jiyoon
• Kim Jinhwa

Classifications

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/1391

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

• H01M4/364

  as mixtures · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/505

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