Proton-conductive complex oxide and fuel cell using same as electrolyte

Patent metadata

Field	Value
Publication number	US-2018179080-A1
Application number	US-201615753904-A
Country	US
Kind code	A1
Filing date	Aug 19, 2016
Priority date	Aug 21, 2015
Publication date	Jun 28, 2018
Grant date	—

Abstract

Provided is a complex oxide that has a space group I-43d, has a high hydrogen content, contains almost no impurity phase, exhibits almost no aluminum substitution in the structure thereof, and is suitable for proton conductivity. This complex oxide is represented by a chemical formula Li 7-x-y H x La 3 Zr 2-y M y O 12 (M represents Ta and/or Nb, 3.2<x≤7-y, and 0.25<y<2) and is a single phase of a garnet type structure belonging to a cubic system, and the crystal structure thereof is a space group I-43d.

First claim

1 . A complex oxide that is represented by a chemical formula Li 7-x-y H x La 3 Zr 2-y M y O 12 (M represents Ta and/or Nb, 3.2<x≤7-y, and 0.25<y<2) and is a single phase of a garnet type structure belonging to a cubic system.

2 . The complex oxide according to claim 1 ,
wherein a crystal structure thereof is a space group I-43d.

3 . A proton conductor comprising:
the complex oxide according to claim 1 .

4 . A fuel cell comprising:
a fuel electrode; an air electrode; and a solid electrolyte containing the proton conductor according to claim 3 .

5 . A method for producing the complex oxide according to claim 1 , comprising:
an exchange step of bringing a raw material complex oxide represented by a chemical formula Li 7-x-y H x La 3 Zr 2-y M y O 12 (M represents Ta and/or Nb, 0≤x≤3.2, and 0.25<y<2) and a compound having a hydroxy group or a carboxy group into contact with each other to exchange at least some of lithium of the raw material complex oxide and hydrogen of the compound having a hydroxy group or a carboxy group.

6 . The method for producing the complex oxide according to claim 5 ,
wherein the compound having a hydroxy group or a carboxy group is included in an acidic aqueous solution or is pure water or alcohol.

7 . The method for producing the complex oxide according to claim 5 ,
wherein in the exchange step, the raw material complex oxide and the compound having a hydroxy group or a carboxy group are brought into contact with each other at a temperature of 80° C. to 200° C.

8 . The method for producing the complex oxide according to claim 5 ,
wherein in the exchange step, the raw material complex oxide and the compound having a hydroxy group or a carboxy group are brought into contact with each other for 12 hours or longer.

Assignees

• Aist

Inventors

• Akimoto Junji
• HAMAO Naoki
• Kataoka Kunimitsu

Classifications

• C01G33/006 Primary

  Compounds containing niobium, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• C01G35/006 Primary

  Compounds containing tantalum, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• C01P2002/30

  Three-dimensional structures · CPC title

• C01P2006/40

  Electric properties · CPC title

• H01M4/88

  Processes of manufacture · CPC title