Production of nanostructured Li4Ti5O12 with superior high rate performance

Patent metadata

Field	Value
Publication number	US-9327990-B2
Application number	US-201214137110-A
Country	US
Kind code	B2
Filing date	Jun 27, 2012
Priority date	Jun 27, 2011
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

A process of preparing nanostructured lithium titanate particles. The process contains the steps of providing a solvent containing a soft-template compound, a lithium ion-containing compound, and a titanium ion-containing compound; removing the solvent to obtain a lithium titanate precursor; and calcining the precursor followed by milling and annealing. Also disclosed is a nanostructured lithium titanate particle prepared by this process.

First claim

What is claimed is:

1. A process of preparing nanostructured lithium titanate particles, the process comprising:
providing a solvent containing a soft-template compound, a lithium ion-containing compound, and a titanium ion-containing compound;
removing the solvent to obtain a lithium titanate precursor; and
calcining the lithium titanate precursor to obtain crystalline lithium titanate particles,

wherein the solvent is a mixture of ethanol and water, the lithium ion-containing compound and the titanium ion-containing compound are in a stoichiometric proportion, and the weight ratio of the soft-template compound to the lithium ion-containing compound is 1:2 to 3:2.

2. The process of claim 1 , further comprising, after the calcining step, ball milling the crystalline lithium titanate particles at 200 to 600 rpm for 1 to 5 hours to yield milled lithium titanate particles.

3. The process of claim 2 , wherein the crystalline lithium titanate particles are ball milled at 300 to 400 rpm for 3 to 4 hours.

4. The process of claim 2 , further comprising annealing the milled lithium titanate particles at 400 to 750° C. for 1 to 5 hours to yield nanostructured lithium titanate particles.

5. The process of claim 4 , wherein the milled lithium titanate particles are annealed at 500 to 700° C. for 1 to 2 hours.

6. The process of claim 1 , wherein the lithium titanate precursor is calcined at 600 to 800° C. for 2 to 8 hours.

7. The process of claim 6 , wherein the lithium titanate precursor is calcined at 600 to 750° C. for 4 to 6 hours.

8. The process of claim 1 , wherein the soft-template compound is dodecyltrimethyl-ammonium bromide, cetyltrimethylammonium bromide, octadecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, decyltrimethylammonium bromide, or octyltrimethyl-ammonium bromide; and the solvent is a mixture of ethanol and water, in which the weight ratio of ethanol to water is 1:1 to 6:1.

9. The process of claim 8 , wherein the lithium ion-containing compound is lithium acetate, lithium chloride, lithium hydroxide, or lithium carbonate, and the titanium ion-containing compound is titanium isopropoxide.

10. The process of claim 9 , further comprising, after the calcining step, ball milling the crystalline lithium titanate particles at 200 to 600 rpm for 1 to 5 hours to yield milled lithium titanate particles and annealing the milled lithium titanate particles at 400 to 750° C. for 1 to 5 hours to yield nanostructured lithium titanate particles, wherein the lithium titanate precursor is calcined at 600 to 800° C. for 2 to 8 hours.

11. The process of claim 10 , wherein the lithium titanate precursor is calcined at 600 to 750° C. for 4 to 6 hours, the crystalline lithium titanate particles are ball milled at 300 to 400 rpm for 3 to 4 hours, and the milled lithium titanate particles are annealed at 500 to 700° C. for 1 to 2 hours.

12. The process of claim 9 , wherein the lithium ion-containing compound is lithium acetate or lithium chloride and the titanium ion-containing compound is titanium isopropoxide.

13. The process of claim 12 , further comprising, after the calcining step, ball milling the crystalline lithium titanate particles at 200 to 600 rpm for 1 to 5 hours to yield milled lithium titanate particles and annealing the milled lithium titanate particles at 400 to 750° C. for 1 to 5 hours to yield nanostructured lithium titanate particles, wherein the lithium titanate precursor is calcined at 600 to 800° C. for 2 to 8 hours.

14. The process of claim 13 , wherein the lithium titanate precursor is calcined at 600 to 750° C. for 4 to 6 hours, the crystalline lithium titanate particles are ball milled at 300 to 400 rpm for 3 to 4 hours, and the milled lithium titanate particles are annealed at 500 to 700° C. for 1 to 2 hours.

15. The process of claim 8 , wherein the soft-template compound is cetyl trimethylammonium bromide, dodecyl trimethylammonium bromide, or octyl trimethylammonium bromide; and the solvent is a mixture of ethanol and water, in which the weight ratio of ethanol to water is 1:1 to 3:1.

16. The process of claim 15 , wherein the lithium ion-containing compound is lithium acetate, lithium chloride, lithium hydroxide or lithium carbonate; and the titanium ion-containing compound is titanium isopropoxide.

17. The process of claim 16 , further comprising, after the calcining step, ball milling the crystalline lithium titanate particles at 200 to 600 rpm for 1 to 5 hours to yield milled lithium titanate particles and annealing the milled lithium titanate particles at 400 to 750° C. for 1 to 5 hours to yield nanostructured lithium titanate particles, wherein the lithium titanate precursor is calcined at 600 to 800° C. for 2 to 8 hours.

18. The process of claim 17 , wherein the lithium titanate precursor is calcined at 600 to 750° C. for 4 to 6 hours, the crystalline lithium titanate particles are ball milled at 300 to 400 rpm for 3 to 4 hours, and the milled lithium titanate particles are annealed at 500 to 700° C. for 1 to 2 hours.

19. The process of claim 16 , wherein the lithium ion-containing compound is lithium acetate or lithium chloride and the titanium ion-containing compound is titanium isopropoxide.

20. The process of claim 19 , further comprising, after the calcining step, ball milling the crystalline lithium titanate particles at 200 to 600 rpm for 1 to 5 hours to yield milled lithium titanate particles and annealing the milled lithium titanate particles at 400 to 750° C. for 1 to 5 hours to yield nanostructured lithium titanate particles, wherein the lithium titanate precursor is calcined at 600 to 800° C. for 2 to 8 hours.

21. A nanostructured lithium titanate particle prepared by the process of claim 1 , the nanostructured lithium titanate particle having a particle size of 30 to 500 nm and a pore size of 3 to 10 nm.

22. A nanostructured lithium titanate particle comprising spinel Li 4 Ti 5 O 12 crystals, wherein the particle has a particle size of 30 to 500 nm and a pore size of 3 to 10 nm.

Assignees

• Balaya Palani
• Hariharan Srirama
• Univ Singapore

Inventors

• Balaya Palani
• Hariharan Srirama

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/485

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

• C01G23/005

  Alkali titanates · CPC title

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title

• C01P2006/40

  Electric properties · CPC title