Positive active material for alkaline secondary battery, method for manufacturing the same and alkaline secondary battery

Patent metadata

Field	Value
Publication number	US-9269952-B2
Application number	US-201213978957-A
Country	US
Kind code	B2
Filing date	Jan 11, 2012
Priority date	Jan 11, 2011
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

A positive active material for an alkaline secondary battery having a core layer containing nickel hydroxide and a conductive auxiliary layer which coats the surface of the core layer, wherein the conductive auxiliary layer contains a cobalt oxyhydroxide phase and a cerium dioxide phase, and the active material contains lithium.

First claim

The invention claimed is:

1. A positive active material for an alkaline secondary battery comprising a core layer containing nickel hydroxide and a conductive auxiliary layer which coats a surface of the core layer, wherein
the conductive auxiliary layer contains a cobalt oxyhydroxide phase having a rhombohedral crystal structure and a space group R3m crystal structure and a cerium dioxide phase having a fluorite crystal structure and a space group Fm3m crystal structure,
the active material contains lithium, and
the conductive auxiliary layer comprises 10 atomic % or more and 70 atomic % or less cerium.

2. The positive active material for an alkaline secondary battery according to claim 1 , wherein
the active material is subjected to a lithium impregnation treatment.

3. The positive active material for an alkaline secondary battery according to claim 1 , wherein the core layer and the conductive auxiliary layer contain lithium.

4. The positive active material for an alkaline secondary battery according to claim 1 , wherein an amount of lithium contained in the active material corresponds to 0.03% by mass or more and 0.36% by mass or less of lithium as element.

5. The positive active material for an alkaline secondary battery according to claim 1 , wherein the existence ratio of the cerium dioxide phase to a total of the cobalt oxyhydroxide phase and the cerium dioxide phase in the conductive auxiliary layer is 6.5% by mass or more and 88.2% by mass or less.

6. An alkaline secondary battery comprising the positive active material for an alkaline secondary battery according to claim 1 .

7. An alkaline secondary battery comprising:
a positive active material for an alkaline secondary battery having a core layer containing nickel hydroxide and a conductive auxiliary layer which coats the surface of the core layer, wherein the conductive auxiliary layer contains a cobalt oxyhydroxide phase having a rhombohedral crystal structure and a space group R3m crystal structure and a cerium dioxide phase having a fluorite crystal structure and a space group Fm3m crystal structure, and the conductive auxiliary layer comprises 10 atomic % or more and 70 atomic % or less cerium; and
an electrolyte solution containing lithium hydroxide.

8. The alkaline secondary battery according to claim 6 , further comprising an electrolyte solution containing lithium hydroxide.

9. The alkaline secondary battery according to claim 7 , wherein the electrolyte solution contains lithium hydroxide of 0.25 mol/L or more and 1 mol/L or less.

10. The positive active material for an alkaline secondary battery according to claim 1 , wherein the cobalt oxyhydroxide phase comprises cerium at 3a1 site, 3a2 site, or combination thereof of the crystal structure, and the cerium dioxide phase comprises cobalt at 4a site of the crystal structure.

11. The alkaline secondary battery according to claim 7 , wherein the cobalt oxyhydroxide phase comprises cerium at 3a1 site, 3a2 site, or combination thereof of the crystal structure, and the cerium dioxide phase comprises cobalt at 4a site of the crystal structure.

12. The positive active material for an alkaline secondary battery according to claim 1 , wherein the conductive auxiliary layer comprises 30 atomic % or more and 70 atomic % or less cerium.

13. The alkaline secondary battery according to claim 7 , wherein the conductive auxiliary layer comprises 30 atomic % or more and 70 atomic % or less cerium.

Assignees

• Kakeya Tadashi
• Kanemoto Manabu
• Kodama Mitsuhiro
• Gs Yuasa Int Ltd

Inventors

• Kakeya Tadashi
• Kanemoto Manabu
• Kodama Mitsuhiro

Classifications

• H01M4/366

  as layered products · CPC title

• C01G51/00

  Compounds of cobalt · CPC title

• H01M4/382

  Lithium (H01M4/405 takes precedence) · CPC title

• C01P2004/32

  Spheres · CPC title

• C01P2002/77

  by unit-cell parameters, atom positions or structure diagrams · CPC title