Sulfide-Based Solid Electrolyte for Lithium Ion Cell, and Solid Electrolyte Compound

Patent metadata

Field	Value
Publication number	US-2017352916-A1
Application number	US-201515538667-A
Country	US
Kind code	A1
Filing date	Dec 25, 2015
Priority date	Dec 26, 2014
Publication date	Dec 7, 2017
Grant date	—

Abstract

Relating to a sulfide-based solid electrolyte compound for lithium ion batteries which has a cubic argyrodite-type crystal structure, to provide a compound which can suppress a generation amount of hydrogen sulfide when being left to stand in the air and which can maintain high conductivity even when being left to stand in dry air. Proposed is a sulfide-based solid electrolyte compound for lithium ion batteries containing a crystal phase of the cubic argyrodite-type crystal structure and represented by a composition formula (1): Li 7-x+y PS 6-x Cl x+y , wherein x and y in the composition formula (1) satisfy 0.05≦y≦0.9 and −3.0x+1.8≦y≦−3.0x+5.7.

First claim

1 . A sulfide-based solid electrolyte compound for a lithium ion battery comprising a crystal phase of a cubic argyrodite-type crystal structure, and
being represented by a composition formula (1): Li 7-x+y PS 6-x Cl x+y , wherein x and y in the composition formula (1) satisfy 0.05≦y≦0.9 and −3.0x+1.8≦y≦−3.0x+5.7.

2 . The sulfide-based solid electrolyte compound for a lithium ion battery according to claim 1 , wherein x and y in the composition formula (1) satisfy 0.05≦y≦0.4 and −3.0x+3.9≦y≦−3.0x+5.7.

3 . A solid electrolyte comprising the sulfide-based solid electrolyte compound for a lithium ion battery according to claim 1 .

4 . The solid electrolyte according to claim 3 comprising a single phase of the crystal phase of the cubic argyrodite-type crystal structure.

5 . The solid electrolyte according to claim 3 comprising the crystal phase of the cubic argyrodite-type crystal structure and a crystal phase which is represented by LiCl.

6 . The solid electrolyte according to claim 3 ,
wherein, in an X-ray diffraction pattern, a ratio [IL(200)/IA(220)] of a peak intensity IL(200) of a (200) plane of the LiCl crystal phase with respect to a peak intensity IA(220) of a (220) plane of the cubic argyrodite-type crystal phase is 0.30 or less.

7 . A method for producing the sulfide-based solid electrolyte compound for a lithium ion battery having the solid electrolyte according to claim 3 ,
wherein 38.8 to 72.0 parts (mol %) of lithium sulfide (Li 2 S) powder, 10.2 to 12.4 parts (mol %) of diphosphorus pentasulfide (P 2 S 5 ) powder, and 15.6 to 51.0 parts (mol %) of lithium chloride (LiCl) powder are mixed, and the resultant mixture is calcined at 350 to 500° C. under an inert atmosphere, or at 350 to 550° C. under an atmosphere comprising a hydrogen sulfide gas.

8 . A lithium ion battery comprising the solid electrolyte according to claim 3 .

9 . A lithium ion battery comprising the solid electrolyte according to claim 3 , and a negative electrode active material containing carbon or silicon.

10 . An application method of a lithium ion battery comprising
the solid electrolyte according to claim 3 , a negative electrode active material containing silicon, and a positive electrode active material containing a lithium composite oxide, wherein, in charge and discharge cycles, a termination voltage in a first charging is set to be higher than a termination voltage in a second or later charging.

11 . A solid electrolyte comprising the sulfide-based solid electrolyte compound for a lithium ion battery according to claim 2 .

12 . The solid electrolyte according to claim 11 comprising a single phase of the crystal phase of the cubic argyrodite-type crystal structure.

13 . The solid electrolyte according to claim 11 comprising the crystal phase of the cubic argyrodite-type crystal structure and a crystal phase which is represented by LiCl.

14 . The solid electrolyte according to claim 11 ,
wherein, in an X-ray diffraction pattern, a ratio [IL(200)/IA(220)] of a peak intensity IL(200) of a (200) plane of the LiCl crystal phase with respect to a peak intensity IA(220) of a (220) plane of the cubic argyrodite-type crystal phase is 0.30 or less.

15 . A lithium ion battery comprising the solid electrolyte according to claim 4 .

16 . A lithium ion battery comprising the solid electrolyte according to claim 5 .

17 . A lithium ion battery comprising the solid electrolyte according to claim 6 .

18 . A lithium ion battery comprising the solid electrolyte according to claim 11 .

Assignees

• Mitsui Mining & Smelting Co

Inventors

• Miyashita Norihiko
• Chikumoto Takashi
• Aoki Tatsuya
• Ide Hitohiko
• Matsuzaki Kenji

Classifications

• H01M2300/0068

  inorganic · CPC title

• H01M10/44

  Methods for charging or discharging (circuits for charging H02J7/00) · CPC title

• H01M10/0525

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

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title