Lithium-ion-conductive solid electrolyte and solid-electrolyte lithium battery

• US 6,277,524 B1
• Filed: 12/08/1998
• Issued: 08/21/2001
• Est. Priority Date: 12/09/1997
• Status: Expired due to Term

• Current Assignee: Genesis Research Institute, Inc., Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Genesis Research Institute, Inc., Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kanno, Ryoji
• Primary Examiner(s): Ryan, Patrick
• Assistant Examiner(s): Pittman, Zidia T.
• Application Number:
  US09/206,961
• Time in Patent Office: 987 Days
• Field of Search: 429/206, 429/223, 429/304, 429/344, 429/345, 296/231
• US Class Current: 429/304
• CPC Class Codes: C03C 3/321 Chalcogenide glasses, e.g. containing S, Se, Te
• CPC Class Codes: C03C 4/18 for ion-sensitive glass
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0562 Solid materials
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 6/18 with solid electrolyte
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A lithium-ion-conductive solid electrolyte includes a lithium-ion-conductive substance expressed by a general formula Li₂S-GeS₂-X wherein “X” is at least one member selected from the group consisting of Ga₂S₃ and ZnS, or Li₂S-SiS₂-P₂S₅. It is superb in terms of stability and safety at elevated temperatures, since it is a crystalline solid of high ion conductivity. It can be applied to a solid electrolyte for lithium batteries.

Claims

1. A lithium-ion-conductive solid electrolyte, comprising:

a crystalline lithium-ion-conductive substance expressed by a general formula Li₂S-GeS₂-X wherein “

X”

is at least one member selected from the group consisting of Ga₂S₃ and ZnS.

2. The lithium-ion-conductive solid electrolyte according to claim 1, wherein said lithium-ion-conductive substance includes Li₂S, GeS₂ and X in a molar ratio of Li₂S:

GeS₂;

X=(from 0.25 to

     6);

(from 0 (not inclusive to

     1);

(from 0 (not inclusive) to

     1).

3. The lithium-ion-conductive solid electrolyte according to claim 2, wherein said crystalline lithium-ion-conductive substance includes Li₂S, GeS₂ and X in a molar ratio of Li₂S:

GeS₂;

X=(from 2.2 to 2.3);

(from 0.5 to 0.8);

(from 0.1 to 0.25).

4. The lithium-ion-conductive solid electrolyte according to claim 1, wherein said crystalline lithium-ion-conductive substance has a composition being surrounded by points “

A”

, “

B”

, “

C” and

“

D”

shown in a ternary system;

Li₂S-GeS₂-Ga₂S₃ illustrated in accompanying FIG. 1.

5. The lithium-ion-conductive solid electrolyte according to claim 1, wherein said crystalline lithium-ion-conductive substance includes Li₂S, GeS₂ and Ga₂S₃ in a molar ratio of Li₂S:

GeS₂;

Ga₂S₃=2.2;

0.8;

0.1.

6. The lithium-ion-conductive solid electrolyte according to claim 1, wherein said crystalline lithium-ion-conductive substance includes Li₂S, GeS₂ and Ga₂S₃ in a molar ratio of Li₂S:

GeS₂;

Ga₂S₃=2.225;

0.75;

0.125.

7. The lithium-ion-conductive solid electrolyte according to claim 1, wherein said crystalline lithium-ion-conductive substance includes Li₂S, GeS₂ and Ga₂S₃ in a molar ratio of Li₂S:

GeS₂;

Ga₂S₃=2.25;

0.7;

0.15.

8. The lithium-ion-conductive solid electrolyte according to claim 1, wherein said crystalline lithium-ion-conductive substance is expressed by a chemical formula Li_4+x+d(Ge₁₋

xGa_x)<sub>1−

d</sub>S₄.

9. The lithium-ion-conductive solid electrolyte according to claim 8, wherein the value “

x”

falls in the range of 0.2<

“

x”

<

0.6.

10. The lithium-ion-conductive solid electrolyte according to claim 1, wherein said crystalline lithium-ion-conductive substance is expressed by a chemical formula Li₄₋

2yGe<sub>1−

y</sub>Zn_yS₄.

11. The lithium-ion-conductive solid electrolyte according to claim 10, wherein the value “

y”

falls in the range of 0<

“

y”

<

0.1.

12. The lithium-ion-conductive solid electrolyte according to claim 1, wherein said crystalline lithium-ion-conductive substance includes Li₂S, GeS₂ and ZnS in a molar ratio of Li₂S:

GeS₂;

ZnS=(from 1.0 to 2.0);

(1.0;

(from 0.0 to 1.0).

13. A lithium-ion-conductive solid electrolyte, comprising:

a crystalline lithium-ion-conductive substance expressed by a general formula Li₂S-SiS₂-P₂S₅.

14. The lithium-ion-conductive solid electrolyte according to claim 13, wherein said crystalline lithium-ion-conductive substance includes Li₂S, SiS₂ and P₂S₅ in a molar ratio of Li₂S:

SiS₂;

P₂S₅=(from 1.5 to 2.0);

(from 0.0 to 1.0);

(from 0.0 to 0.5).

15. A solid-electrolyte lithium battery comprising:

a solid electrolyte including a crystalline lithium-ion-conductive substance,

the crystalline lithium-ion-conductive substance expressed by at least one general formula selected from the group consisting of Li₂S-GeS₂-X wherein “

X”

is at least one member selected from the group consisting of Ga₂S₃ and ZnS, and Li₂S-SiS₂-P₂S₅;

a cathode; and

an anode.

16. The solid-electrolyte lithium battery according to claim 15, wherein

the cathode includes a mixture of a cathode active material and the crystalline lithium-ion conductive substance; and

the anode includes a mixture of an anode active material and the crystalline lithium-ion conductive substance.