Positive electrode active material for rechargeable lithium battery, positive electrode containing the same, and rechargeable lithium battery including the same

Patent metadata

Field	Value
Publication number	US-2025379215-A1
Application number	US-202519073676-A
Country	US
Kind code	A1
Filing date	Mar 7, 2025
Priority date	Jun 11, 2024
Publication date	Dec 11, 2025
Grant date	—

Abstract

Examples include a positive electrode active material for a rechargeable lithium battery, a positive electrode including the positive electrode active material, and a rechargeable lithium battery including the positive electrode active material. A positive electrode active material includes a first particle having an olivine crystal structure and having a first average particle diameter, a second particle having an olivine crystal structure and having a second average particle diameter smaller than the first average particle diameter, and a third particle having an olivine crystal structure and having a third average particle diameter larger than the first average particle diameter.

First claim

What is claimed is:

1 . A positive electrode active material comprising:
a first particle having an olivine crystal structure, and having a first average particle diameter; a second particle having an olivine crystal structure, and having a second average particle diameter smaller than the first average particle diameter; and a third particle having an olivine crystal structure, and having a third average particle diameter larger than the first average particle diameter, wherein at least one of the first to third particles includes a compound represented by Formula 1 below:

where, in Formula 1 above, 0.8≤a1≤1.2, 0.950≤x1≤0.999, 0.001≤y1≤0.05, 0≤b1≤0.05, and 0.99≤x1+y1≤1.01, and B1 comprises at least one of Ti and Mg.

2 . The positive electrode active material of claim 1 , wherein the first particle is a secondary particle including a plurality of first primary particles.

3 . The positive electrode active material of claim 2 ,
wherein the first primary particle has an average size in a range of about 200 nm to about 350 nm, and the first average particle diameter is in a range of about 1 μm to about 5 μm.

4 . The positive electrode active material of claim 1 ,
wherein the first particle comprises a first coating layer containing carbon, and an amount of carbon in the first particle is in a range of about 1.4 wt % to about 1.7 wt %.

5 . The positive electrode active material of claim 1 , wherein the first particle has a specific surface area in a range of about 8 m 2 /g to about 12 m 2 /g.

6 . The positive electrode active material of claim 1 , wherein a span value, obtained by analysis on the first particle using a particle size analyzer, is in a range of about 1.33 to about 1.5.

7 . The positive electrode active material of claim 1 , wherein the first particle has a porosity in a range of about 15% to about 20%.

8 . The positive electrode active material of claim 1 , wherein an amount of the first particle is in a range of about 60 wt % to about 85 wt % with respect to a total weight of the first to third particles.

9 . The positive electrode active material of claim 1 ,
wherein the second average particle diameter is in a range of about 0.5 μm to about 2.5 μm, and the third average particle diameter is in a range of about 5 μm to about 10 μm.

10 . The positive electrode active material of claim 1 ,
wherein the second particle comprises at least one second primary particle, and the third particle comprises a substantially sphere-shaped secondary particle including a plurality of third primary particles.

11 . The positive electrode active material of claim 1 , wherein a mixing ratio of the second particle to the third particle is in a range of about 1:1 to about 1:3 on the basis of weight.

12 . The positive electrode active material of claim 1 ,
wherein at least one of the first to third particles comprises a coating layer containing carbon, an amount of carbon on a surface of the first particle is greater than an amount of carbon on a surface of the second particle, and the amount of carbon on the surface of the first particle is less than an amount of carbon on a surface of the third particle.

13 . The positive electrode active material of claim 1 ,
wherein a porosity of the first particle is less than a porosity of the second particle, and the porosity of the first particle is less than a porosity of the third particle.

14 . A positive electrode for a rechargeable lithium battery, the positive electrode comprising:
a positive electrode current collector; and a positive electrode active material layer on the positive electrode current collector, wherein the positive electrode active material layer includes the positive electrode active material according to claim 1 , a conductive material, and a binder.

15 . The positive electrode of claim 14 , wherein a current density of the positive electrode is equal to or greater than about 4.5 mA/cm 2 .

16 . The positive electrode of claim 14 , wherein a mixture density of the positive electrode is equal to or greater than about 2.5 g/cc.

17 . The positive electrode of claim 14 , wherein an amount of the binder is in a range of about 0.5 parts by weight to about 5 parts by weight with respect to 100 parts by weight of the positive electrode active material layer.

18 . The positive electrode of claim 14 , wherein the binder comprises at least one of polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinylchloride, carboxylated polyvinylchloride, polyvinylfluoride, a polymer including ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, a styrene-butadiene rubber, a (meth)acrylate styrene-butadiene rubber, an epoxy resin, a (meth)acrylic resin, a polyester resin, and nylon.

19 . The positive electrode of claim 14 , wherein an amount of the conductive material is in a range of about 0.5 parts by weight to about 5 parts by weight with respect to 100 parts by weight of the positive electrode active material layer.

20 . The positive electrode of claim 14 , wherein the conductive material comprises at least one of a carbon-based material; a metal-based material in a form of a metal powder or a metal fiber; and a conductive polymer.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Suh Soonsung
• Lee Minju
• Lee Boram
• Choi Aram
• Kim Young-Ki

Classifications

• H01M4/131

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

• H01M10/0525

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

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M4/364 Primary

  as mixtures · CPC title

• H01M4/366

  as layered products · CPC title