Lithium sulfide-carbon complex, process for producing the complex, and lithium ion secondary battery utilizing the complex

Patent metadata

Field	Value
Publication number	US-9337476-B2
Application number	US-200913120237-A
Country	US
Kind code	B2
Filing date	Aug 24, 2009
Priority date	Sep 24, 2008
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

The present invention provides a process for producing a lithium sulfide-carbon composite, the process comprising placing a mixture of lithium sulfide and a carbon material having a specific surface area of 60 m 2 /g or more in an electrically-conductive mold in a non-oxidizing atmosphere, and applying a pulsed direct current to the mold while pressurizing the mixture in a non-oxidizing atmosphere, thereby subjecting the lithium sulfide and the carbon material to heating reaction; and a lithium sulfide-carbon composite obtained by this process, the composite having a carbon content of 15 to 70 weight %, and a tap density of 0.4 g/cm 3 or more when the carbon content is 30 weight % or more, or a tap density of 0.5 g/cm 3 or more when the carbon content is less than 30 weight %. The present invention can improve the electronic conductivity of lithium sulfide, which is expected to be put into practical use as a high-capacity positive electrode active material, so as to further enhance the performance of lithium sulfide as a positive electrode active material for lithium ion secondary batteries.

First claim

The invention claimed is:

1. A process for producing a lithium sulfide-carbon composite, the process comprising:
placing a mixture consisting of lithium sulfide and a carbon material having a specific surface area of 60 m 2 /g or more in an electrically-conductive mold in a non-oxidizing atmosphere; and
applying a pulsed direct current to the mold while pressurizing the mixture in a non-oxidizing atmosphere, thereby subjecting the lithium sulfide and the carbon material to heating reaction,
wherein lithium sulfide-carbon composite comprises lithium sulfide and a carbon material bonded together, the composite having a carbon content of 15 to 70 weight %, and a tap density of 0.4 g/cm 3 or more when the carbon content is 30 weight % or more, or a tap density of 0.5 g/cm 3 or more when the carbon content is less than 30 weight %.

2. The process according to claim 1 , wherein the carbon material is acetylene black, and the amount of carbon material used is 15 to 70 weight % based on the total amount of lithium sulfide and carbon material.

3. The process according to claim 1 or 2 , wherein the reaction is carried out at 700 to 1,400° C. under a pressure of 10 MPa or greater.

Assignees

• Takeuchi Tomonari
• Sakaebe Hikari
• Sakai Tetsuo
• Tatsumi Kuniaki
• Senoh Hiroshi
• Kageyama Hiroyuki
• Tabuchi Mitsuharu
• Nat Inst Of Advanced Ind Scien

Inventors

• Takeuchi Tomonari
• Sakaebe Hikari
• Sakai Tetsuo
• Tatsumi Kuniaki
• Senoh Hiroshi
• Kageyama Hiroyuki
• Tabuchi Mitsuharu

Classifications

• C01B31/00

  Chemistry & Metallurgy · mapped topic

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/0438

  by electrochemical processing (electroless electrochemical plating C23C18/54) · CPC title

• H01M4/136 Primary

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M4/1397

  of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title