Surface treating method of negative electrode for magnesium secondary battery, negative electrode for magnesium secondary battery, and magnesium secondary battery

Patent metadata

Field	Value
Publication number	US-9515317-B2
Application number	US-201314136231-A
Country	US
Kind code	B2
Filing date	Dec 20, 2013
Priority date	Dec 26, 2012
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

A surface treating method of a negative electrode for a magnesium secondary battery is provided, wherein the magnesium secondary battery includes: a negative electrode capable of releasing magnesium ions during discharging and capable of precipitating elemental magnesium during charging; a positive electrode capable of precipitating a magnesium oxide during the discharging and capable of releasing magnesium ions during the charging; and a non-aqueous ion conductor for conducting magnesium ions as conduction species. The surface treating method comprises initializing the negative electrode by performing the discharging to form a bare surface at a surface of the negative electrode.

First claim

What is claimed is:

1. A surface treating method of a negative electrode for a magnesium secondary battery, wherein the magnesium secondary battery includes: a negative electrode for releasing magnesium ions during discharging and for precipitating elemental magnesium during charging; a positive electrode for precipitating a magnesium oxide during the discharging and for releasing magnesium ions during the charging; and a non-aqueous ion conductor for conducting magnesium ions as conduction species,
the surface treating method comprising:
performing an initializing discharge process to initialize the negative electrode, wherein the initializing discharge process includes, by performing discharging, forming a bare surface at a surface of the negative electrode, and
in the initializing discharge process, the discharging is performed by supplying an electric current from an external power supply under a condition that satisfies the following relation:
X×Y≧ 1.3 mA 2 h/cm 4 ,

where
X is a discharge capacity density expressed as X mAh/cm 2 , and
Y is a discharge current density expressed as Y mA/cm 2 .

2. The surface treating method according to claim 1 , wherein
the negative electrode comprises a magnesium-based metal.

3. The surface treating method according to claim 1 , wherein
just after the initializing discharge process, the negative electrode has an impedance of 1000 Ωcm 2 or less.

4. The surface treating method according to claim 1 , wherein
in the initializing discharge process, the discharging is performed until the entire surface of the negative electrode becomes the bare surface.

5. The surface treating method according to claim 1 , wherein:
an active substance of the positive electrode is oxygen; and
in the initializing discharge process, the discharging is performed in a state where the magnesium secondary battery has been assembled and oxygen is supplied in a battery system.

6. A surface treating method of a negative electrode for a magnesium secondary battery, wherein the magnesium secondary battery includes: a negative electrode for releasing magnesium ions during discharging and for precipitating elemental magnesium during charging; a positive electrode for precipitating a magnesium oxide during the discharging and for releasing magnesium ions during the charging; a non-aqueous ion conductor for conducting magnesium ions as conduction species,
the surface treating method comprising:
performing an initializing discharge process to initialize the negative electrode, wherein the initializing discharge process includes, by performing discharging, forming a bare surface at a surface of the negative electrode; and
performing a charge process after the initializing discharge process, wherein the charge process includes, by performing charging, forming a magnesium film at the surface of the negative electrode, and
in the initializing discharge process, the discharging is performed by supplying an electric current from an external power supply under a condition that satisfies the following relation:
X×Y≧ 1.3 mA 2 h/cm 4 ,

where
X is a discharge capacity density expressed as X mAh/cm 2 , and
Y is a discharge current density expressed as Y mA/cm 2 .

7. The surface treating method according to claim 6 , wherein
after the initializing discharge process, the charge process is performed.

8. The surface treating method according to claim 6 , wherein
the positive electrode active material of the positive electrode is oxygen, and
in the charge process, the charging is performed in a state where the magnesium secondary battery has been assembled and oxygen is supplied in a battery system.

9. The surface treating method according to claim 6 , wherein
a charge capacity density in the charge process is less than or equal to a discharge capacity density in the initializing discharge process.

10. The surface treating method according to claim 6 , wherein
just after the charge process, the negative electrode has an impedance of 100 Ωcm 2 or less just after the charge process.

11. The surface treating method according to claim 6 , wherein
in the charge process, the charging is performed at a charge current density of 0.5 mA/cm 2 or higher.

12. The surface treating method according to claim 6 , wherein
the magnesium film has a lower density than the negative electrode.

13. The surface treating method according to claim 6 , wherein
the magnesium film on the surface of the negative electrode is formed to have a thickness larger than a thickness calculated based on the discharge capacity density.

14. The surface treating method according to claim 6 , wherein
the magnesium film has voids with a pore diameter of 10 Å to 20 Å.

15. The surface treating method according to claim 6 , wherein
the magnesium film has a composition containing oxygen.

16. The surface treating method according to claim 6 , wherein
the magnesium film contains elemental magnesium and magnesium oxide.

17. The surface treating method according to claim 16 , wherein
the magnesium oxide in the magnesium film contains magnesium peroxide and a magnesium monoxide.

18. The surface treating method according to claim 16 , wherein
the magnesium oxide in the magnesium film is amorphous.

Assignees

• Denso Corp

Inventors

• Sakakibara Nobuyoshi
• Adachi Norikazu
• Kami Kenichirou

Classifications

• H01M10/049

  Processes for forming or storing electrodes in the battery container · CPC title

• H01M10/446

  Initial charging measures · CPC title

• H01M10/054

  Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium · CPC title

• C25D3/42

  of light metals · CPC title

• H01M4/381 Primary

  Alkaline or alkaline earth metals elements (H01M4/40 takes precedence) · CPC title