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

Patent metadata

Field	Value
Publication number	US-2021083287-A1
Application number	US-202017102412-A
Country	US
Kind code	A1
Filing date	Nov 23, 2020
Priority date	Dec 4, 2017
Publication date	Mar 18, 2021
Grant date	—

Abstract

A positive electrode for a rechargeable lithium battery includes a positive active material for a rechargeable lithium battery that includes a first positive active material including a secondary particle including at least two agglomerated primary particles, where at least a portion of the primary particles has a radial arrangement structure, and a second positive active material having a monolith structure, wherein the first and second positive active materials each include a nickel-based positive active material, and an X-ray diffraction (XRD) peak intensity ratio (I(003)/I(104)) of the positive electrode is greater than or equal to about 3. Further embodiments provide a method of manufacturing the positive electrode for rechargeable lithium battery, and a rechargeable lithium battery including the same.

First claim

What is claimed is:

1 . A positive electrode for a rechargeable lithium battery, comprising:
a positive active material 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 an X-ray diffraction (XRD) peak intensity ratio (I(003)/I(104)) of the positive electrode is greater than or equal to about 3.

2 . The positive electrode of claim 1 , wherein the X-ray diffraction (XRD) peak intensity ratio (I(003)/I(104)) of the positive electrode is greater than or equal to about 3.2.

3 . The positive electrode of claim 1 , wherein the positive electrode for the rechargeable lithium battery has a mixture density of greater than or equal to about 3.4 g/cc.

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

5 . The positive electrode 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.

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

7 . The positive electrode 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.

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

9 . The positive electrode of claim 1 , wherein an average particle diameter of the second positive active material is about 3 μm to about 6 μm.

10 . The positive electrode of claim 1 , wherein a residual lithium concentration in the positive active material is less than or equal to about 1000 ppm.

11 . The positive electrode 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 electrode 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 electrode 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, the second nickel-based oxide having a monolith structure; mixing the first nickel-based oxide and the second nickel-based oxide to obtain a mixture; subjecting the mixture to a third heat-treatment in a third oxidizing gas atmosphere to obtain a positive active material comprising a first positive active material and a second positive active material having a monolith structure; mixing the positive active material, a conductive agent, and a binder in a solvent to prepare a positive active material slurry; coating the positive active material slurry on a current collector and then drying it to prepare the positive electrode; and pressing the positive electrode to a density of greater than or equal to about 3.4 g/cc.

14 . 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.

15 . 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.

16 . The method of claim 13 , 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.

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

18 . A method of preparing a rechargeable lithium battery, the method comprising:
preparing the positive electrode according to the method of claim 13 ; preparing a negative electrode; and providing an electrolyte to the positive electrode and the negative electrode.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Ahn Kiyong
• Kim Jongmin

Classifications

• C01G53/82 Primary

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

• H01M4/131

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

• C01P2002/74

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

• C01P2004/54

  Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension · CPC title

• C01P2004/20

  extending in two dimensions, e.g. plate-like · CPC title