Solid electrolyte material and method for producing the same

• US 10,403,933 B2
• Filed: 03/28/2018
• Issued: 09/03/2019
• Est. Priority Date: 03/31/2017
• Status: Active Grant

• Current Assignee: Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology)
• Inventors: Kanno, Ryoji, Hori, Satoshi
• Primary Examiner(s): Slifka, Sarah A.
• Application Number:
  US15/938,843
• Publication Number:
  US 20180287205A1
• Time in Patent Office: 524 Days
• Field of Search: None
• CPC Class Codes: C01B 25/14 Sulfur, selenium, or tellurium compounds of phosphorus
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0562 Solid materials
• CPC Class Codes: H01M 2300/0068 inorganic
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

In order to improve the stability of an electrolyte, an object of the present disclosure is to develop, among the sulfide solid electrolytes of Li—P—S—O based containing no metal element other than lithium, a new solid electrolyte having a possibility to have high ion conductivity and a method for producing for obtaining the same easily. The present disclosure achieves the object by providing a solid electrolyte material including a sulfide composition represented by a composition formula Li_4-4y-xP⁴⁺_1+y-xP⁵⁺_xS_4-zO_z (Li_4-4y-xP_1+yS_4-zO_z), wherein 0.6≤x<1, 0≤z≤0.2, and −0.025≤y≤0.1, and a method for producing the same.

Claims

1. A solid electrolyte material comprising a sulfide composition represented by a composition formula Li_4-4y-xP⁴⁺_1+y-xP⁵⁺_xS_4-zO_z (Li_4-4y-xP_1+yS_4-zO_z), wherein 0.6≤

x<

1, 0≤

z≤

0.2, and −

0.025≤

y≤

0.1.

2. The solid electrolyte material according to claim 1, wherein the solid electrolyte material has a peak at a position of 2θ

=29.58°

±

0.50°

in X-ray diffraction measurement using a CuKα

ray, and

the solid electrolyte material does not have a peak at a position of 2θ

=27.33°

±

0.50°

in X-ray diffraction measurement using a CuKα

ray, or when the solid electrolyte material has a peak at the position of 2θ

=27.33°

±

0.50°

, a diffraction intensity of the peak at 2θ

=29.58°

±

0.50°

is regarded as I_A, and a diffraction intensity of the peak at 2θ

=27.33°

=0.50°

is regarded as I_B, a value of I_B/I_A is less than 0.50.

3. The solid electrolyte material according to claim 1, wherein the solid electrolyte material has a peak at a position of 2θ

=17.90°

±

0.20°

, 29.0°

±

0.50°

, and 29.75°

±

0.25°

in X-ray diffraction measurement using a CuKα

ray, and

the solid electrolyte material does not have a peak at a position of 2θ

=18.50°

+0.20°

in X-ray diffraction measurement using a CuKα

ray, or when the solid electrolyte material has a peak at the position of 2θ

=18.50°

±

0.20°

, a diffraction intensity of the peak at 2θ

=17.90°

±

0.20°

is regarded as I_C, and a diffraction intensity of the peak at 2θ

=18.50°

±

0.20°

is regarded as I_D, a value of I_D/I_C is less than 0.50.

4. The solid electrolyte material according to claim 1, wherein the solid electrolyte material has a peak at a position of 2θ

=18.0°

±

0.1°

, 19.4°

±

0.1°

, 21.9°

±

0.1°

, 24.0°

±

0.1° and

31.3°

±

0.1°

in X-ray diffraction measurement using a CuKα

ray.

5. The solid electrolyte material according to claim 1, wherein the solid electrolyte material has a peak at a position of 2θ

=17.8°

±

0.1°

, 19.1°

±

0.1°

, 21.7°

±

0.1°

, 23.8°

±

0.1° and

30.85°

±

0.1°

in X-ray diffraction measurement using a CuKα

ray.

6. The solid electrolyte material according to claim 1, wherein ion conductivity is 0.4 mS/cm or more.

7. A method for producing the solid electrolyte material according to claim 1, the method comprising:

an ion conductive material synthesizing step of synthesizing an ion conductive material using a simple substance of P, a P compound, a S compound, a Li compound, and an O compound as a raw material including a constituent of the sulfide composition; and

a heating step of obtaining the sulfide composition by heating the ion conductive material.

8. The method according to claim 7, wherein a heating temperature in the heating step is in a range of 230°

C. to 300°

C.