Positive electrode active material for nickel-hydrogen secondary battery, nickel-hydrogen secondary battery including the positive electrode active material, and method of evaluating positive electrode active material

Patent metadata

Field	Value
Publication number	US-10177385-B2
Application number	US-201615349933-A
Country	US
Kind code	B2
Filing date	Nov 11, 2016
Priority date	Nov 16, 2015
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A nickel-hydrogen secondary battery includes an electrode group including a separator, a positive electrode and a negative electrode, the positive electrode includes a positive electrode active material, the positive electrode active material includes a composite particle including a compound of Co and a compound of Ni, and the ratio R represented by A/B satisfies a relationship of R≥0.3, when the amount of jumping in the X-ray absorption fine structure spectrum of the Co in 7600 to 7800 eV and the amount of jumping in the X-ray absorption fine structure spectrum of the Ni in 8300 to 8500 eV obtained by measurement according to a conversion electron yield method are defined as A and B, respectively.

First claim

What is claimed is:

1. A positive electrode active material for a nickel-hydrogen secondary battery, comprising:
a composite particle comprising a compound of Co and a compound of Ni,
wherein a ratio R represented by A/B satisfies a relationship of R≥0.3, when an amount of jumping in an X-ray absorption fine structure (XAFS) spectrum of the Co in 7600 to 7800 eV and an amount of jumping in an X-ray absorption fine structure (XAFS) spectrum of the Ni in 8300 to 8500 eV obtained by measurement according to a conversion electron yield method are defined as A and B, respectively.

2. The positive electrode active material for a nickel-hydrogen secondary battery according to claim 1 , wherein:
the composite particle comprises a base particle comprising nickel hydroxide as the compound of Ni, and a conductive layer covering a surface of the base particle and comprising the compound of Co, and
the conductive layer comprises an alkali metal.

3. The positive electrode active material for a nickel-hydrogen secondary battery according to claim 2 , wherein the alkali metal is Na.

4. The positive electrode active material for a nickel-hydrogen secondary battery according to claim 2 , wherein the alkali metal is Na and Li.

5. A nickel-hydrogen secondary battery comprising:
a container, and
an electrode group accommodated together with an alkaline electrolytic solution in the container, wherein:
the electrode group comprises a positive electrode and a negative electrode stacked with a separator being interposed therebetween,
the positive electrode comprises a positive electrode active material, and
the positive electrode active material comprises a composite particle comprising a compound of Co and a compound of Ni, wherein a ratio R represented by A/B satisfies a relationship of R≥0.3, when an amount of jumping in an X-ray absorption fine structure (XAFS) spectrum of the Co in 7600 to 7800 eV and an amount of jumping in an X-ray absorption fine structure (XAFS) spectrum of the Ni in 8300 to 8500 eV obtained by measurement according to a conversion electron yield method are defined as A and B, respectively.

6. The nickel-hydrogen secondary battery according to claim 5 , wherein:
the composite particle comprises a base particle comprising nickel hydroxide as the compound of Ni, and a conductive layer covering a surface of the base particle and comprising the compound of Co, and
the conductive layer comprises an alkali metal.

7. The nickel-hydrogen secondary battery according to claim 6 , wherein the alkali metal is Na.

8. The nickel-hydrogen secondary battery according to claim 6 , wherein the alkali metal is Na and Li.

9. A method of evaluating a positive electrode active material for a nickel-hydrogen secondary battery, comprising:
preparing a positive electrode active material powder comprising a composite particle comprising a compound of Co and a compound of Ni,
irradiating the positive electrode active material powder with an X-ray, and sensing an amount of jumping A in an X-ray absorption fine structure (XAFS) spectrum of the Co in 7600 to 7800 eV and an amount of jumping B in an X-ray absorption fine structure (XAFS) spectrum of the Ni in 8300 to 8500 eV obtained by measurement according to a conversion electron yield method, and
determining whether a relationship of R≥0.3 is satisfied, when a ratio of the amount of jumping A to the amount of jumping B, represented by A/B, is defined as R.

Assignees

• Fdk Corp
• Fujitsu Ltd

Inventors

• Imoto Yuzo
• Ito Takeshi
• Yasuoka Shigekazu
• Doi Shuuichi
• Yamazaki Takashi
• Kataoka Yuji

Classifications

• H01M4/366

  as layered products · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/30

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

• H01M10/345

  Gastight metal hydride accumulators · CPC title

• H01M4/32

  Nickel oxide or hydroxide electrodes · CPC title