Process for manufacturing lithium titanium oxides

Patent metadata

Field	Value
Publication number	US-9966599-B2
Application number	US-201414895202-A
Country	US
Kind code	B2
Filing date	May 30, 2014
Priority date	Jun 4, 2013
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

Provided is lithium titanate that is readily pulverized, and readily dispersed in a binding agent. The lithium titanate is characterized in that the value of a degree of pulverization Zd representing the ratio of the 50% cumulative diameter pre- and post-pulverization is 2 or greater. The lithium titanate is produced by the following steps (1)-(3). (1) a step in which titanyl sulfate or titanium sulfate is thermally hydrolyzed to produce metatitanic acid; (2) a step in which a slurry containing the metatitanic acid is prepared, and the slurry, subsequent to neutralization to bring the pH to 6.0-9.0, undergoes solid-liquid separation, to produce a metatitanic acid-containing titanium starting material having a BET specific surface area of 100-400 m 2 /g, and in which the sulfuric acid (SO 4 ) content is 0.01-2.0 mass % with respect to the amount of metatitanic acid, on a TiO 2 -converted basis; and (3) a step in which the titanium starting material and a lithium compound are mixed and baked.

First claim

The invention claimed is:

1. A lithium titanate granulated particle, comprising particles having a degree of grinding Zd, represented by the following Formula 1 is 2 or more,
Zd=D 50,1 /D 50,2  (Formula 1)

wherein D50,1 is a cumulative 50% particle diameter (μm) of lithium titanate before grinding, and D50,2 is a cumulative 50% particle diameter (μm) of the lithium titanate after grinding, resulting in the granulated particle having a physical characteristic such that 1 g of a sample is placed within a circle having an area of 2 cm 2 and pressed with a load at a pressure of 35 MPa applied to the sample for 1 minute, and
the lithium titanate granulated particle has a particle size distribution represented by a SD value being 2.0 to 8.0 um, wherein the SD value is represented by the following Formula 2,
SD (μm)=( D 90− D 10)/2  Formula 2

wherein D10 is a cumulative 10% particle diameter of lithium titanate granulated particle, and D90 is a cumulative 90% particle diameter of lithium titanate granulated particle, and
the chemical formula is Li x Ti y O 4 ,
wherein 0.8<x<1.4 and 1.6<y<2.2.

2. The lithium titanate granulated particle according to claim 1 , having a cumulative 50% particle diameter (D50,1) of 0.5 to 50 μm and a 330 mesh sieve residue of 0.1% by mass or less.

3. The lithium titanate granulated particle according to claim 2 , having a BET specific surface area of 5 to 50 m 2 /g.

4. A lithium titanate granulated particle, comprising particles having a degree of grinding Zd, represented by the following Formula 1, is 2 or more,
Zd=D 50,1 /D 50,2  (Formula 1)

wherein D50,1 is a cumulative 50% particle diameter (μm) of lithium titanate before grinding, and D50,2 is a cumulative 50% particle diameter (μm) of the lithium titanate after grinding, and
the lithium titanate granulated particle having a particle size distribution represented by a SD value being 2.0 to 8.0 μm, wherein the SD value is represented by the following Formula 2,
SD (μm)=( D 90− D 10)/2,  Formula 2

wherein D10 is a cumulative 10% particle diameter of lithium titanate granulated particle, and D90 is a cumulative 90% particle diameter of lithium titanate granulated particle, and
the chemical formula is Li x Ti y O 4 ,
wherein 0.8<x<1.4 and 1.6<y<2.2.

5. The lithium titanate granulated particle according to claim 1 , having a BET specific surface area of 5 to 50 m 2 /g.

6. A method for producing lithium titanate granulated particle according to claim 4 , comprising the steps of:
(1) thermally hydrolyzing titanyl sulfate or titanium sulfate to produce metatitanic acid;
(2) preparing a slurry comprising the metatitanic acid, neutralizing the slurry to pH 6.0 to 9.0, and then subjecting the slurry to solid-liquid separation to produce a titanium raw material comprising metatitanic acid having a BET specific surface area of 100 to 400 m 2 /g and a content of a sulfuric acid component (SO 4 ) of 0.01 to 2.0% by mass based on an amount of the metatitanic acid in terms of TiO 2 ; and
(3) mixing the titanium raw material and a lithium compound and then firing an obtained mixture to produce the lithium titanate granulated particle.

7. The method for producing lithium titanate granulated particle according to claim 6 , wherein in the step of (2), after the metatitanic acid is subjected to solid-liquid separation, the metatitanic acid is dried and dry-ground to produce the titanium raw material comprising the metatitanic acid.

8. The method for producing lithium titanate granulated particle according to claim 6 , wherein the step of (3) is a step of preparing a mixed slurry of the metatitanic acid-containing titanium raw material and a lithium compound and then firing the mixed slurry.

9. The method for producing lithium titanate granulated particle according to claim 6 , wherein the step of (3) is a step of preparing a mixed slurry of the metatitanic acid-containing titanium raw material and a lithium compound, then wet-grinding the mixed slurry, and then firing the mixed slurry.

10. The method for producing lithium titanate granulated particle according to claim 9 , wherein in the step of (3), wet-grinding is performed so that a cumulative 50% particle diameter of the titanium raw material is in a range of 0.5 to 3.0 μm.

11. The method for producing lithium titanate granulated particle according to claim 8 , wherein in the step of (3), the mixed slurry is dried and granulated before firing.

12. The method for producing lithium titanate granulated particle according to claim 6 , wherein in the step of (3), firing is performed at a temperature of 600 to 950° C.

13. The method for producing lithium titanate granulated particle according to claim 6 , further comprising a step of (4) further dry-grinding lithium titanate.

14. An electric storage device electrode obtained by mixing at least the lithium titanate granulated particle or the lithium titanate powder according to claim 1 and a binding agent and fixing an obtained mixture to a current collector.

15. An electric storage device comprising at least the electrode according to claim 14 , a counter electrode to the electrode, and an electrolyte.

16. A method for producing an electric storage device electrode, comprising a step of mixing at least lithium titanate produced by the method according to claim 6 with a binding agent and fixing an obtained mixture to a current collector.

17. An electric storage device comprising at least an electrode produced by the method according to claim 16 , a counter electrode to the electrode, and an electrolyte.

Assignees

• Ishihara Sangyo Kaisha

Inventors

• Horie Hiroomi
• Nagahashi Naoya
• Takeuchi Tsunehisa

Classifications

• H01M4/485 Primary

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• C01G23/04

  Oxides; Hydroxides · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• C01G23/005

  Alkali titanates · CPC title

• H01M4/0404

  by coating on electrode collectors · CPC title