Sulfide solid electrolyte for all-solid secondary battery, method of preparing same, and all-solid secondary battery including the same

Patent metadata

Field	Value
Publication number	US-11955601-B2
Application number	US-202117412589-A
Country	US
Kind code	B2
Filing date	Aug 26, 2021
Priority date	Aug 31, 2020
Publication date	Apr 9, 2024
Grant date	Apr 9, 2024

Abstract

A sulfide solid electrolyte for all-solid secondary batteries, a method of preparing the same, and an all-solid secondary battery, the sulfide solid electrolyte including lithium, phosphorus, sulfur, and a halogen, wherein: the sulfide solid electrolyte has an argyrodite-type crystal structure, a ratio (I (29.0) /I (30.0) ratio) of a peak intensity at a 2θ of 29±0.1° to a peak intensity at a 2θ of 30±0.1° is 0.06 or less, the peak intensities being obtained by X-ray diffraction analysis of the sulfide solid electrolyte, and a ratio (I (27.1) /I (30.0) ratio) of a peak intensity at a 2θ of 27.1±0.1° to a peak intensity at a 2θ of 30±0.1° is 0.06 or less, the peak intensities being obtained by X-ray diffraction analysis of the sulfide solid electrolyte.

First claim

What is claimed is:

1. A sulfide solid electrolyte for all-solid secondary batteries, the sulfide solid electrolyte being a compound represented by Formula 1 below,
Li a P 1 S b X c   Formula 1

in Formula 1,
X may be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I), and
4.7<a<5.3, 4.4≤b≤4.5, and 0.7<c<1.5,
wherein:
the sulfide solid electrolyte has an argyrodite-type crystal structure,
a ratio (I (29.0) /I (30.0) ratio) of a peak intensity at a 2θ of 29±0.1° to a peak intensity at a 2θ of 30±0.1° is 0.06 or less, the peak intensities being obtained by X-ray diffraction analysis of the sulfide solid electrolyte, and
a ratio (I (27.1) /I (30.0) ratio) of a peak intensity at a 2θ of 27.1±0.1° to a peak intensity at a 2θ of 30±0.1° is 0.06 or less, the peak intensities being obtained by X-ray diffraction analysis of the sulfide solid electrolyte.

2. The sulfide solid electrolyte for all-solid secondary batteries as claimed in claim 1 , wherein the I (29.0) /I (30.0) ratio is from 0.0006 to 0.04.

3. The sulfide solid electrolyte for all-solid secondary batteries as claimed in claim 1 , wherein the I (27.1) /I (30.0) ratio is from 0.055 to 0.059.

4. The sulfide solid electrolyte for all-solid secondary batteries as claimed in claim 1 , wherein an atomic ratio of lithium to sulfur (Li/S) in the sulfide solid electrolyte is 1.13 or higher.

5. The sulfide solid electrolyte for all-solid secondary batteries as claimed in claim 1 , wherein:
the sulfide solid electrolyte is a compound represented by Formula 2 below,
Li a PS b Cl c   Formula 2

in Formula 2,
5.04≤a≤5.28, 4.4≤b≤4.5, and 1.13≤c≤1.34.

6. The sulfide solid electrolyte for all-solid secondary batteries as claimed in claim 1 , wherein the compound represented by Formula 1 is Li 5.04 PS 4.46 Cl 1.13 , Li 5.28 PS 4.47 Cl 1.34 , Li 5.20 PS 4.44 Cl 1.32 , Li 5.20 PS 4.46 Cl 1.29 , or a combination thereof.

7. The sulfide solid electrolyte for all-solid secondary batteries as claimed in claim 1 , wherein the sulfide solid electrolyte has a Young's modulus of 80 GPa or higher.

8. The sulfide solid electrolyte for all-solid secondary batteries as claimed in claim 1 , wherein the sulfide solid electrolyte has an ionic conductivity of 2 mS/cm or higher.

9. An all-solid secondary battery, comprising:
a positive electrode layer;
a negative electrode layer; and
a solid electrolyte layer therebetween,
wherein the positive electrode layer or the solid electrolyte layer includes the sulfide solid electrode as claimed in claim 1 .

10. The all-solid secondary battery as claimed in claim 9 , wherein:
the negative electrode layer includes a negative current collector, a first negative active material layer, and a second negative active material layer,
the second negative active material layer is on the first negative active material layer or between the negative current collector and the first negative active material layer, and
the second negative active material layer includes lithium or a lithium alloy.

11. The all-solid secondary battery as claimed in claim 9 , wherein:
the negative electrode layer includes a negative current collector and a first negative active material layer, and
a carbon layer is between the first negative active material layer and the solid electrolyte layer.

12. A method of preparing the sulfide solid electrolyte for all-solid secondary batteries as claimed in claim 8 , the method comprising:
mixing a sulfur precursor, a phosphorus precursor, and a halogen precursor, as precursors for forming a sulfide solid electrode, to prepare a precursor mixture, and then contacting
the precursor mixture of the sulfur precursor, the phosphorus precursor, and the halogen precursor; and
heat-treating the precursor mixture at a temperature of 350° C. or higher.

13. The method as claimed in claim 12 , wherein the heat-treating is performed under vacuum conditions at a temperature of 500° C. to 650° C. for 5 hours or longer.

14. The method of claim 12 , wherein the contacting of the precursor mixture comprises
mechanically milling the sulfur (S) precursor, the phosphorus (P) precursor, and the halogen precursor.

Assignees

• Samsung Sdi Co Ltd
• Industry Academia Cooperation Group Of Sejong Univ

Inventors

• Sohn Dongrak
• Song Minsang
• Han Jungmin
• Ryu Younggyoon
• Lee Kyulin
• Yi Jeongdoo
• Han Sangil
• Sohn Keesun
• Shim Sunggeun
• Lee Jinhee

Classifications

• H01M10/0562 Primary

  Solid materials · CPC title

• C01B17/22

  Alkali metal sulfides or polysulfides · CPC title

• H01M4/366

  as layered products · CPC title

• H01M4/382

  Lithium (H01M4/405 takes precedence) · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title