Positive electrode for all-solid secondary battery and all-solid secondary battery including the same

Patent metadata

Field	Value
Publication number	US-11909043-B2
Application number	US-202117190733-A
Country	US
Kind code	B2
Filing date	Mar 3, 2021
Priority date	Mar 3, 2020
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A positive electrode for an all-solid secondary battery including a sulfide-based solid electrolyte includes a first positive active material having an average particle diameter of about 15 μm to about 20 μm, a second positive active material having an average particle diameter of about 2 μm to about 6 μm, and a solid electrolyte, wherein at least one selected from the first positive active material and the second positive active material includes a coating layer including a lithium ion conductor, and each of the first positive active material and the second positive active material includes a core and a shell, wherein the shell includes a nickel-based active material containing cobalt. An all-solid secondary battery includes the positive electrode.

First claim

What is claimed is:

1. A positive electrode for an all-solid secondary battery including a sulfide-based solid electrolyte, the positive electrode comprising:
a first positive active material having an average particle diameter of about 15 μm to about 20 μm,
a second positive active material having an average particle diameter of about 2 μm to about 6 μm, and
a solid electrolyte,
wherein at least one selected from the first positive active material and the second positive active material comprises a coating layer, the coating layer comprising a lithium ion conductor,
wherein each of the first positive active material and the second positive active material comprises a core and a shell,
wherein the shell of the first positive active material or the second positive active material comprises a nickel-based active material comprising cobalt (Co), and
wherein the core of the first positive active material or the second positive active material comprises a nickel-based active material with less cobalt (Co) than that of the corresponding shell.

2. The positive electrode of claim 1 , wherein an amount of cobalt in the nickel-based active material of the shell is about 30 mol % or higher.

3. The positive electrode of claim 1 , wherein the lithium ion conductor is a lithium zirconium oxide, a lithium titanium oxide, a lithium niobium oxide, a lithium lanthanum oxide, a lithium cerium oxide, or a combination thereof.

4. The positive electrode of claim 1 , wherein the lithium ion conductor is a compound represented by Formula 1:
a Li 2 O—ZrO 2 ,  Formula 1

 and
wherein, in Formula 1, 0.1≤a≤2.0.

5. The positive electrode of claim 1 , wherein the nickel-based active material in the shell is a compound represented by Formula 2:
Li a Ni 1-x-y-z Co x M1 y M2 z O 2 ,  Formula 2

 and
wherein, in Formula 2, M1 is manganese (Mn) or aluminum (Al),
M2 is boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zirconium (Zr), aluminum (Al), or a combination thereof, and
0.9≤a≤1.3, 0.3≤x≤0.6, 0.002≤y≤0.05, 0≤z<1, and x+y+z<1.

6. The positive electrode of claim 1 , wherein an amount of the first positive active material is about 60 parts to about 80 parts by weight based on 100 parts by weight of a total weight of the first positive active material and the second positive active material.

7. The positive electrode of claim 1 , wherein the core of the first positive active material and the core of the second positive active material are each a compound represented by Formula 3:
Li a (Ni 1-x-y-z Co x M1 y M2 z )O 2 ,  Formula 3

 and
wherein, in Formula 3, M1 is manganese (Mn), aluminum (Al), or a combination thereof,
M2 is boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zirconium (Zr), aluminum (Al), or a combination thereof, and
0.9≤a≤1.3, x≤(1−x−y−z), y≤(1−x−y−z), 0<x<1, 0≤y<1, and 0≤z<1.

8. The positive electrode of claim 7 , wherein an amount of nickel (Ni) in the compound represented by Formula 3 is about 80 mol % to about 98 mol %.

9. The positive electrode of claim 1 , wherein an amount of the lithium ion conductor is about 0.1 parts to about 5 parts by weight based on 100 parts by weight of a total weight of the nickel-based active material and the lithium ion conductor.

10. The positive electrode of claim 1 , wherein a mixture density of the positive electrode is about 3.4 g/cm 3 to about 3.7 g/cm 3 .

11. A positive electrode for an all-solid secondary battery including a sulfide-based solid electrolyte, the positive electrode comprising:
a first positive active material having an average particle diameter of about 15 μm to about 20 μm,
a second positive active material having an average particle diameter of about 2 μm to about 6 μm, and
a solid electrolyte,
wherein at least one selected from the first positive active material and the second positive active material comprises a coating layer, the coating layer comprising a lithium ion conductor,
wherein each of the first positive active material and the second positive active material comprises a core and a shell,
wherein the shell of the first positive active material or the second positive active material comprises a nickel-based active material comprising cobalt (Co), and
wherein the solid electrolyte is about 5 parts to about 10 parts by weight based on 100 parts by weight of a total weight of the positive electrode.

12. A positive electrode for an all-solid secondary battery including a sulfide-based solid electrolyte, the positive electrode comprising:
a first positive active material having an average particle diameter of about 15 μm to about 20 μm,
a second positive active material having an average particle diameter of about 2 μm to about 6 μm, and
a solid electrolyte,
wherein at least one selected from the first positive active material and the second positive active material comprises a coating layer, the coating layer comprising a lithium ion conductor,
wherein each of the first positive active material and the second positive active material comprises a core and a shell,
wherein the shell of the first positive active material or the second positive active material comprises a nickel-based active material comprising cobalt (Co), and
wherein an amount of the nickel-based active material in the shell is about 0.1 parts to about 10 parts by weight based on 100 parts by weight of a total weight of the nickel-based active material of the corresponding core and the nickel-based active material of the corresponding shell.

13. An all-solid secondary battery comprising:
the positive electrode of claim 1 ;
a negative electrode; and
a solid electrolyte layer between the positive electrode and the negative electrode,
wherein the solid electrolyte layer comprises the sulfide-based solid electrolyte.

14. The all-solid secondary battery of claim 13 , wherein the sulfide-based solid electrolyte is at least one selected from Li 2 S—P 2 S 5 , Li 2 S—P 2 S 5 —LiCl, Li 2 S—P 2 S 5 —LiBr, Li 2 S—P 2 S 5 —LiCl—LiBr, Li 2 S—P 2 S 5 —Li 2 O, Li 2 S—P 2 S 5 —Li 2 O—LiI, Li 2 S—SiS 2 , Li 2 S—SiS 2 —LiI, Li 2 S—SiS 2 —LiBr, Li 2 S—SiS 2 —LiCl, Li 2 S—SiS 2 —B 2 S 3 —LiI, Li 2 S—SiS 2 —P 2 S 5 —LiI, Li 2 S—B 2 S 3 , Li 2 S—P 2 S 5 —Z m S n (where m and n are each a positive number, and Z is one of Ge, Zn, or Ga), Li 2 S—GeS 2 , Li 2 S—SiS 2 —Li 3 PO 4 , Li 2 S—SiS 2 -Li p MO q (where p and q are each a positive number, and M is one of P, Si, Ge, B, Al, Ga, or In), Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0≤x≤2), and Li 7-x PS 6-x I x (where 0≤x≤2).

15. The all-solid secondary battery of claim 13 , wherein the negative electrode comprises a negative current collector and a first negative active material layer on the negative current collector, and
wherein the first negative active material layer comprises a negative active material and a binder, the negative active material is in a form of particles, and an average particle diameter of the negative active material is about 4 μm or less.

16. The all-solid secondary battery of claim 15 , wherein the negative active material comprises at least one selected from a carbonaceous negative active material, a metal negative active material, and a metalloid negative active material, and
wherein the carbonaceous negative active material comprises at least one selected from amorphous carbon and crystalline carbon.

17. The all-solid secondary battery of claim 13

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kwon Taeri

Classifications

• H01M4/525 Primary

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

• H01M4/131 Primary

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

• H01M4/366

  as layered products · CPC title

• H01M10/0525

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

• H01M2004/028

  Positive electrodes · CPC title