Lithium titanate powder for electrode of energy storage device, active material, and energy storage device using the same

Patent metadata

Field	Value
Publication number	US-9850139-B2
Application number	US-201515312494-A
Country	US
Kind code	B2
Filing date	May 21, 2015
Priority date	May 21, 2014
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Provided is a lithium titanate powder for an electrode of an energy storage device, an active material containing the same, and an energy storage device using the active material. The lithium titanate powder comprises Li 4 Ti 5 O 12 as a main component, and wherein, when a volume surface diameter calculated from specific surface area determined by the BET method is D BET and a crystallite diameter calculated from half-peak width of (111) plane of Li 4 Ti 5 O 12 by the Scherrer equation is D X , D BET is 0.1 to 0.6 μm; D X is larger than 80 nm; D BET /D X (μm/μm), ratio of D BET to D X , is 3 or less; M (wherein M is at least one type of metal element selected from a group consisting of Mg, Zn, Al, Ga, and In) is contained; and when atomic concentrations of the M and titanium at 5 nm inner positions from a surface of a lithium titanate particle are D 1 (atm %) and Dti (atm %) respectively, and when atomic concentration of the M at 100 nm inner position from the lithium titanate particle surface is D 2 (atm %), following formulas (I) and (II) are satisfied.

D 1/ D 2≧5  (I)

0.02≦ D 1/ Dti ≦0.4  (II)

First claim

What is claimed is:

1. A lithium titanate powder, comprising Li 4 Ti 5 O 12 as a main component, wherein,
when a volume surface diameter calculated from specific surface area determined by the BET method is represented as D BET , and when a crystallite diameter calculated from a half-peak width of the peak for (111) plane of Li 4 Ti 5 O 12 by the Scherrer equation is represented as D X ,
D BET is 0.1 to 0.6 μm,
D X is larger than 80 nm,
D BET /D X (μm/μm), ratio of D BET to D X , is 3 or less,

the lithium titanate powder comprises M, wherein M is at least one type of metal element selected from the group consisting of Mg, Zn, Al, Ga, and In, and
in a cross-sectional analysis of a lithium titanate particle using a scanning transmission electron microscope, when atomic concentration of the M and atomic concentration of titanium measured by energy dispersive X-ray spectroscopy at the 5 nm inner position from a surface of the lithium titanate particle along a straight line drawn vertically to tangent of the lithium titanate particle surface are D1 (atm %) and Dti (atm %) respectively, and when atomic concentration of the M at 100 nm inner position from the surface of the lithium titanate particle along the straight line is D2 (atm %), following formulas (I) and (II) are satisfied:
D 1/ D 2≧5  (I)

0.02≦ D 1/ Dti≦ 0.4  (II).

2. The lithium titanate powder according to claim 1 , wherein a following formula (III) is satisfied:
0.02≦ D 1/ Dti≦ 0.3  (III).

3. The lithium titanate powder according to claim 1 , wherein a ratio D BET /D X (μm/μm), is 2 or less.

4. The lithium titanate powder according to claim 1 , wherein T M /T Ti , atomic ratio of M to Ti for the entire lithium titanate powder measured by the inductivity coupled plasma emission spectrometric analysis method is 0.001 to 0.05.

5. An active material, comprising a lithium titanate powder according to claim 4 .

6. An electrode sheet, comprising an active material according to claim 5 .

7. An energy storage device, comprising an active material according to claim 5 .

8. A lithium-ion secondary battery, comprising an active material according to claim 5 .

9. A hybrid capacitor, comprising an active material according to claim 5 .

10. An active material comprising a lithium titanate powder according to claim 1 .

11. An electrode sheet, comprising an active material according to claim 10 .

12. An energy storage device, comprising an active material according to claim 10 .

13. A lithium-ion secondary battery, comprising an active material according to claim 10 .

14. A hybrid capacitor, comprising an active material according to claim 10 .

Assignees

• Ube Industries

Inventors

• Takemoto Hirofumi
• Tanaka Yoshizumi
• Fujino Hiroshi
• Iwamoto Yasumasa

Classifications

• H01G11/50

  specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation · CPC title

• H01G11/46

  Metal oxides · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• C01P2006/12

  Surface area · CPC title

• H01G11/06

  with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC] · CPC title