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

Patent metadata

Field	Value
Publication number	US-11984583-B2
Application number	US-202117190770-A
Country	US
Kind code	B2
Filing date	Mar 3, 2021
Priority date	Mar 3, 2020
Publication date	May 14, 2024
Grant date	May 14, 2024

Abstract

A positive electrode for an all-solid secondary battery includes a positive active material and a sulfide-based solid electrolyte, wherein the positive active material has a structure containing a core and a shell, the shell includes a nickel-based active material containing cobalt at an amount of about 30 mol % or higher, a surface of the positive active material includes a coating layer including at least one lithium ion conductor selected from a lanthanum oxide and a lithium lanthanum oxide, and an amount of the lithium ion conductor is in a range of about 0.1 parts to about 10 parts by weight based on 100 parts by weight of the total weight of the positive active material and the lithium ion conductor.

First claim

What is claimed is:

1. A positive electrode for an all-solid secondary battery,
the positive electrode comprising a positive active material and a sulfide-based solid electrolyte,
wherein:
the positive active material has a structure containing a core and a shell,
the shell comprises a first nickel-based active material containing cobalt (Co), a thickness of the shell, comprising the first nickel-based active material containing cobalt, being in a range of about 5 nm to about 100 nm,
a surface of the positive active material comprises a coating layer comprising at least one lithium ion conductor selected from a lanthanum oxide and a lithium lanthanum oxide, a thickness of the coating layer being in a range of about 0.1 nm to about 50 nm,
an amount of the lithium ion conductor is in a range of about 0.1 parts to about 10 parts by weight based on 100 parts by weight of the total weight of the positive active material and the lithium ion conductor,
wherein an amount of the shell is in a range of about 0.3 parts to about 10 parts by weight based on 100 parts by weight of the total weight of the positive active material having the structure containing the core and the shell, and
wherein the positive electrode has a density of a mixture comprising the positive active material and the sulfide-based solid electrolyte in a range of about 3.4 g/cm 3 to about 3.7 g/cm 3 .

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

3. The positive electrode of claim 1 , wherein the lithium lanthanum oxide is represented by Formula 1:
aLi 2 O-LaO 2 , and   Formula 1

wherein, in Formula 1, 0.1≤a≤2.0.

4. The positive electrode of claim 1 , wherein the first nickel-based active material containing cobalt (Co) is represented by Formula 2:
Li a Ni 1-x-y-z Co x M1 y M2 z O 2 , and   Formula 2

wherein, in Formula 2, 0.9a1.3,
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,
0.3≤x≤0.6, 0.002≤y≤0.05, 0≤z<1, and x+y+z<1.

5. The positive electrode of claim 1 , wherein an amount of the sulfide-based solid electrolyte is in a range of about 5 parts to about 15 parts by weight based on 100 parts by weight of the total weight of the positive electrode.

6. The positive electrode of claim 1 , wherein the core of the positive active material comprises a second nickel-based active material represented by Formula 3:
Li a (Ni 1-x-y-z Co x M1 y M2 z )O 2 , and   Formula 3

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,
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.

7. The positive electrode of claim 6 , wherein an amount of nickel in the second nickel-based active material represented by Formula 3 is in a range of about 80 mol % to about 98 mol %.

8. 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.

9. The all-solid secondary battery of claim 8 , 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, and 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, and 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).

10. The all-solid secondary battery of claim 8 , wherein the negative electrode comprises a negative current collector and a first negative active material layer on the negative current collector,
the first negative active material layer comprises a negative active material and a binder, the negative active material is in the form of particles, and
an average particle diameter of the negative active material is about 4 μm or less.

11. The all-solid secondary battery of claim 10 , 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.

12. The all-solid secondary battery of claim 11 , wherein the carbonaceous negative active material comprises at least one selected from amorphous carbon and crystalline carbon.

13. The all-solid secondary battery of claim 11 , wherein the metal negative active material and/or metalloid negative active material comprises at least one selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kwon Taeri

Classifications

• H01M4/366 Primary

  as layered products · CPC title

• C01G53/42

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

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M4/505

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