Lithium titanate crystal structure, composite of lithium titanate crystal structure and carbon, method of production thereof, and electrode and electrochemical element employing said composite

Patent metadata

Field	Value
Publication number	US-9368793-B2
Application number	US-201514656867-A
Country	US
Kind code	B2
Filing date	Mar 13, 2015
Priority date	May 4, 2010
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

Highly dispersed lithium titanate crystal structures having a thickness of few atomic layers level and the two-dimensional surface in a plate form are supported on carbon nanofiber (CNF). The lithium titanate crystal structure precursors and CNF that supports these are prepared by a mechanochemical reaction that applies sheer stress and centrifugal force to a reactant in a rotating reactor. The mass ratio between the lithium titanate crystal structure and carbon nanofiber is preferably between 75:25 and 85:15. The carbon nanofiber preferably has an external diameter of 10-30 nm and an external specific surface area of 150-350 cm 2 /g. This composite is mixed with a binder and then molded to obtain an electrode, and this electrode is employed for an electrochemical element.

First claim

The invention claimed is:

1. A composite of lithium titanate crystal structure and carbon, wherein,
the lithium titanate crystal structure having a thickness of 1 nm or less at 2-5 atomic layers level and having one side of the two-dimensional surface spread in a plate form at 5-100 nm,
the dispersed lithium titanate crystal structure is supported on carbon, and
the mass ratio between the lithium titanate crystal structure and carbon is between 75:25 and 85:15.

2. The composite of lithium titanate crystal structure and carbon according to claim 1 , wherein the two-dimensional surface is a (111) face.

3. The composite of lithium titanate crystal structure and carbon according to claim 2 , having a plate crystal structure with a thickness of few atomic layers level obtained by applying sheer stress and centrifugal force are to a solution comprising a titanium source and a lithium source to allow reaction and producing a lithium titanate crystal structure precursor, and heating this precursor.

4. The composite of lithium titanate crystal structure and carbon according to claim 1 , wherein the ratio between the thickness and one side of the two-dimensional surface is between 1:5 and 1:350.

5. The composite of lithium titanate crystal structure and carbon according to claim 4 , having a plate crystal structure with a thickness of few atomic layers level obtained by applying sheer stress and centrifugal force are to a solution comprising a titanium source and a lithium source to allow reaction and producing a lithium titanate crystal structure precursor, and heating this precursor.

6. The composite of lithium titanate crystal structure and carbon according to claim 1 , having a plate crystal structure with a thickness of few atomic layers level obtained by applying sheer stress and centrifugal force are to a solution comprising a titanium source and a lithium source to allow reaction and producing a lithium titanate crystal structure precursor, and heating this precursor.

7. The composite of lithium titanate crystal structure and carbon according to claim 1 , wherein said carbon has an external diameter of 10-30 nm and an external specific surface area of 150-350 cm 2 /g.

8. The composite of lithium titanate crystal structure and carbon according to claim 1 , wherein sheer stress and centrifugal force are applied to a solution comprising a titanium source, a lithium source, and carbon in amounts so that the mass ratio between the lithium titanate crystal structure and carbon of the composite produced is between 75:25 and 85:15 in a rotating reactor to allow reaction and producing a composite of lithium titanate crystal structure precursors and carbon, and heating this composite to obtain a plate lithium titanate crystal structure with a thickness of few atomic layers level supported on carbon.

9. An electrode obtained by mixing the composite according to claim 1 with a binder and then molding.

10. An electrochemical capacitor that employs the electrode according to claim 9 as a negative electrode and a polarizable electrode as a positive electrode.

11. An electrochemical element that employs the electrode according to claim 1 .

12. A method for producing a composite of lithium titanate crystal structure and carbon, in which sheer stress and centrifugal force is applied to a solution comprising a titanium source, a lithium source, and carbon in amounts so that the mass ratio between the lithium titanate crystal structure and carbon of the composite produced is between 75:25 and 85:15 in a rotating reactor to allow reaction and producing a composite of lithium titanate crystal structure precursors and carbon, and a composite of this precursor and carbon are heated to produce a composite of plate lithium titanate crystal structure and carbon having a thickness of few atomic layers level.

Assignees

• Nippon Chemicon

Inventors

• Naoi Katsuhiko
• Naoi Wako
• Ishimoto Shuichi
• Tamamitsu Kenji

Classifications

• Y10S977/896

  Chemical synthesis, e.g. chemical bonding or breaking · CPC title

• C01G23/005

  Alkali titanates · CPC title

• C01P2006/12

  Surface area · CPC title

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• H01G11/36

  Nanostructures, e.g. nanofibres, nanotubes or fullerenes · CPC title