Lithium-iron-phosphorus-sulfur-carbon composite and method for producing same

Patent metadata

Field	Value
Publication number	US-10367196-B2
Application number	US-201515527185-A
Country	US
Kind code	B2
Filing date	Nov 18, 2015
Priority date	Nov 18, 2014
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

A composite containing phosphorus, lithium, iron, sulfur, and carbon as constituent elements wherein lithium sulfide (Li 2 S) is present in an amount of 90 mol % or more, and wherein the crystallite size calculated from the half-width of a diffraction peak based on the (111) plane of Li 2 S as determined by X-ray powder diffraction measurement is 80 nm or less. The composite exhibits a high capacity (in particular, a high discharge capacity) useful as an electrode active material for a lithium-ion secondary battery (in particular, a cathode active material for a lithium-ion secondary battery), without the need for stepwise pre-cycling treatment.

First claim

The invention claimed is:

1. A composite comprising, as constituent elements, lithium, iron, phosphorus, sulfur, and carbon,
wherein lithium sulfide (Li 2 S) is present in an amount of 90 mol % or more, and
wherein the crystallite size calculated from a half-width of a diffraction peak based on the (111) plane of Li 2 S as determined by X-ray powder diffraction measurement is 80 nm or less.

2. The composite according to claim 1 wherein
the Li content is 30 to 55 atomic %,
the Fe content is 2 to 7 atomic %,
the P content is 1 to 5 atomic %,
the S content is 25 to 40 atomic %, and
the C content is 8 to 25 atomic %.

3. A method for producing the composite according to claim 1 , the method comprising
subjecting a mixture containing a lithium-containing compound, an iron-containing compound, a phosphorus-containing compound, a sulfur-containing compound, and a carbon-containing compound to electric current sintering and mechanical milling.

4. The production method according to claim 3 wherein the electric current sintering and the mechanical milling are performed such that after the mixture containing a lithium-containing compound, an iron-containing compound, a phosphorus-containing compound, and a sulfur-containing compound is subjected to the electric current sintering, an obtained electric-current sintered product is subjected to the mechanical milling together with a carbon-containing compound.

5. The production method according to claim 4 wherein the mixture containing a lithium-containing compound, an iron-containing compound, a phosphorus-containing compound, and a sulfur-containing compound is a mixture of lithium sulfide and iron phosphorus trisulfide, and/or a mixture of lithium sulfide, iron sulfide, and phosphorus.

6. The production method according to claim 3 wherein the electric current sintering and/or the mechanical milling is performed in a non-oxidizing atmosphere.

7. The production method according to claim 3 wherein the electric current sintering and/or the mechanical milling is performed in an electric currently conductive die.

8. The production method according to claim 3 wherein the electric current sintering and/or the mechanical milling is performed under increased pressure.

9. An electrode active material for a lithium battery, the material comprising the composite according to claim 1 .

10. A lithium battery comprising, as a constituent element, the electrode active material for a lithium battery according to claim 9 .

11. The lithium battery according to claim 10 that is a lithium-ion secondary battery.

12. An all-solid-state lithium-ion secondary battery comprising, as constituent elements,
the electrode active material for a lithium battery according to claim 9 and
a lithium-ion conductive solid electrolyte.

13. The all-solid-state lithium-ion secondary battery according to claim 12 wherein the lithium-ion conductive solid electrolyte is at least one member selected from the group consisting of polymer-based solid electrolytes, sulfide-based solid electrolytes, and oxide-based solid electrolytes.

14. A method for producing the composite according to claim 2 , the method comprising
subjecting a mixture containing a lithium-containing compound, an iron-containing compound, a phosphorus-containing compound, a sulfur-containing compound, and a carbon-containing compound to electric current sintering and mechanical milling.

15. The production method according to claim 4 wherein the electric current sintering and/or the mechanical milling is performed in a non-oxidizing atmosphere.

16. The production method according to claim 5 wherein the electric current sintering and/or the mechanical milling is performed in a non-oxidizing atmosphere.

17. The production method according to claim 4 wherein the electric current sintering and/or the mechanical milling is performed in an electric currently conductive die.

18. The production method according to claim 5 wherein the electric current sintering and/or the mechanical milling is performed in an electric currently conductive die.

19. The production method according to claim 6 wherein the electric current sintering and/or the mechanical milling is performed in an electric currently conductive die.

20. The production method according to claim 4 wherein the electric current sintering and/or the mechanical milling is performed under increased pressure.

Assignees

• Aist

Inventors

• Takeuchi Tomonari
• Kageyama Hiroyuki
• Sakuda Atsushi
• Sakaebe Hikari

Classifications

• Y02P70/54

  Cross-Sectional Technologies · mapped topic

• H01M4/58

  of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates · CPC title

• C01G49/12

  Sulfides {(C01G49/0018 takes precedence)} · CPC title

• C01B17/22 Primary

  Alkali metal sulfides or polysulfides · CPC title

• H01M4/38

  of elements or alloys · CPC title