Positive electrode active material for alkaline secondary battery and alkaline secondary battery including the positive electrode active material

Patent metadata

Field	Value
Publication number	US-11228027-B2
Application number	US-202016773367-A
Country	US
Kind code	B2
Filing date	Jan 27, 2020
Priority date	Feb 12, 2016
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

A nickel-hydrogen secondary battery includes an electrode group comprising a separator, a positive electrode, and a negative electrode, and the positive electrode contains a positive electrode active material including a base particle comprising a nickel hydroxide particle containing Mn in solid solution and a conductive layer comprising a Co compound and covering the surface of the base particle, wherein the X-ray absorption edge energy of Mn detected within 6500 to 6600 eV by measurement with an XAFS method is 6548 eV or higher.

First claim

What is claimed is:

1. A method of producing a positive electrode active material for an alkaline secondary battery, the positive electrode active material comprising a core particle comprising a solid solution of unoxidized nickel hydroxide and Mn and a Co compound covering the core particle, the method comprising:
an intermediate product particle preparation step of preparing an intermediate product particle including a base particle comprising a nickel hydroxide particle containing Mn in solid solution and a conductive layer comprising a Co compound and covering a surface of the base particle;
a step of preparing a sodium chlorite aqueous solution containing 5.0% to 20.0% sodium chlorite by mass; and
an oxidization step of selectively oxidizing the Mn contained in the intermediate product particle by heating the sodium chlorite aqueous solution and treating the intermediate product particle with the heated aqueous solution such that an X-ray absorption edge energy of the Mn detected within 6500 to 6600 eV by measurement with an XAFS (X-ray Absorption Fine Structure) method is increased to 6548 eV or higher, thereby providing the positive electrode active material.

2. The method of claim 1 , wherein a content of the Mn in the base particle is 0.1% by mass or more and 2.0% by mass or less based on a quantity of the nickel hydroxide.

3. The method of claim 1 , wherein the conductive layer contains an alkali metal.

4. The method of claim 3 , wherein the alkali metal is Na.

5. The method of claim 3 , wherein the alkali metal is Na and Li.

6. The method of claim 1 , wherein the measurement with an XAFS method is XAFS measurement with a fluorescence yield method.

7. A method of producing an alkaline secondary battery comprising a container and an electrode group contained together with an alkaline electrolytic solution in the container, the method comprising:
producing a positive electrode active material according to the method of claim 1 ; and
forming the electrode group with a negative electrode and a positive electrode that contains the positive electrode active material, the negative electrode and the positive electrode being laminated with a separator sandwiched therebetween, the electrode group being provided inside the container; and
injecting the alkaline electrolytic solution into the container.

8. The method of claim 7 , further comprising:
sealing the container after injecting the alkaline electrolytic solution into the container.

Assignees

• Fdk Corp
• Fujitsu Ltd

Inventors

• Ito Takeshi
• Imoto Yuzo
• Kihara Masaru
• Yano Takayuki
• Yasuoka Shigekazu
• Doi Shuuichi
• Yamazaki Takashi
• Kataoka Yuji

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M10/30

  Nickel accumulators (H01M10/34 takes precedence) · CPC title

• C01P2002/52

  containing elements as dopants · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• C01P2002/50

  Solid solutions · CPC title