Oxide electrolyte sintered body and method for producing the same

Patent metadata

Field	Value
Publication number	US-10847794-B2
Application number	US-201715605006-A
Country	US
Kind code	B2
Filing date	May 25, 2017
Priority date	May 27, 2016
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

An oxide electrolyte sintered body with high lithium ion conductivity and a method for producing the same, which can obtain the oxide electrolyte sintered body with high lithium ion conductivity by sintering at lower temperature than ever before. The method for producing an oxide electrolyte sintered body may comprise the steps of: preparing crystal particles of a garnet-type ion-conducting oxide which comprises Li, H, at least one kind of element L selected from the group consisting of an alkaline-earth metal and a lanthanoid element, and at least one kind of element M selected from the group consisting of a transition element that can be 6-coordinated with oxygen and typical elements belonging to the Groups 12 to 15, and which is represented by a general formula (Lix−3y−z,Ey,Hz)LαMβOγ (where E is at least one kind of element selected from the group consisting of Al, Ga, Fe and Si, 3≤x−3y−z≤7, 0≤y<0.22, 0<z≤2.8, 2.5≤α≤3.5, 1.5≤β≤2.5, and 11≤γ≤13); preparing a lithium-containing flux; and sintering a mixture of the crystal particles of the garnet-type ion-conducting oxide and the flux by heating at 400° C. or more and 650° C. or less.

First claim

The invention claimed is:

1. A method for producing an oxide electrolyte sintered body, the method comprising the steps of:
preparing crystal particles of a garnet-type ion-conducting oxide which comprises Li, H, at least one kind of element L selected from the group consisting of an alkaline-earth metal and a lanthanoid element, and at least one kind of element M selected from the group consisting of a transition element that can be 6-coordinated with oxygen and elements belonging to the Groups 12 to 15, and which is represented by a general formula (Li x−3y−z ,E y ,H z )L α M β O γ (where E is at least one kind of element selected from the group consisting of Al, Ga, Fe and Si, 3≤x−3y−z≤7, 0≤y<0.22, 0<z≤2.8, 2.5≤α≤3.5, 1.5≤β≤2.5, and 11≤γ≤13);
preparing a lithium-containing flux; and
sintering a mixture of the crystal particles of the garnet-type ion-conducting oxide and the flux by heating at 400° C. or more and 650° C. or less.

2. The method for producing the oxide electrolyte sintered body according to claim 1 , wherein the element E is Al.

3. The method for producing the oxide electrolyte sintered body according to claim 1 , wherein the element L is La, and the element M is at least one kind of element selected from the group consisting of Zr, Nb and Ta.

4. The method for producing the oxide electrolyte sintered body according to claim 1 , wherein the element M is at least one kind of element selected from the group consisting of Zr and Nb.

5. The method for producing the oxide electrolyte sintered body according to claim 1 , wherein the flux is at least one kind of compound selected from the group consisting of LiNO 3 and LiOH.

6. The method for producing the oxide electrolyte sintered body according to claim 1 , wherein, in the sintering step, the sintering is carried out under a pressure condition more than the atmospheric pressure.

7. The method for producing the oxide electrolyte sintered body according to claim 1 , wherein, in the sintering step, the sintering is carried out by hot-pressing.

8. The method for producing the oxide electrolyte sintered body according to claim 1 , wherein, the general formula is (Li x−3y−z ,Al y ,H z )La 3 (Zr 2−ε ,Nb ε )O 12 (where 3≤x−3y−z≤7, 0≤y≤0.2, 0<z≤2.8, and 0.25≤ε≤0.6).

9. The method for producing the oxide electrolyte sintered body according to claim 1 , wherein the general formula is (Li x−3y−z ,E y ,H z )L α M β O γ (where E is at least one kind of element selected from the group consisting of Al and Ga, 5≤x−3y−z≤7, 0≤y≤0.22, 0<z≤2.0, 2.5≤α≤3.5, 1.5≤β≤2.5, and 11≤γ≤13).

10. An oxide electrolyte sintered body,
wherein the oxide electrolyte sintered body has grain boundaries between crystal particles of a garnet-type ion-conducting oxide which comprises Li, H, at least one kind of element L selected from the group consisting of an alkaline-earth element and a lanthanoid element, and at least one kind of element M selected from the group consisting of a transition element that can be 6-coordinated with oxygen and elements belonging to the Groups 12 to 15, and which is represented by a general formula (Li x−3y−z ,E y ,H z )L α M β O γ (where E is at least one kind of element selected from the group consisting of Al, Ga, Fe and Si, 3≤x−3y−z≤7, 0≤y≤0.22, 0≤z≤2.8, 2.5≤α≤3.5, 1.5≤β≤2.5, and 11≤γ≤13);
wherein a lithium-containing flux is present at grain boundary triple junctions between the crystal particles; and
wherein the oxide electrolyte sintered body satisfies the following formula 1:
R gb /(R b +R gb )≤0.6  Formula 1:

where R b is an intragranular resistance value that is an ion conductivity resistance inside the crystal particles, and R gb is a grain boundary resistance value that is an ion conductivity resistance on grain boundaries between the crystal particles, and
wherein the lithium-containing flux is at least one kind of compound selected from the group consisting of LiNO 3 and LiOH.

11. The oxide electrolyte sintered body according to claim 10 , wherein the element E is Al.

12. The oxide electrolyte sintered body according to claim 10 , wherein the element L is La, and the element M is at least one kind of element selected from the group consisting of Zr, Nb and Ta.

13. The oxide electrolyte sintered body according to claim 10 , wherein the element M is at least one kind of element selected from the group consisting of Zr and Nb.

14. The oxide electrolyte sintered body according to claim 10 , wherein the general formula is (Li x−3y−z ,Al y ,H z )La 3 (Zr 2−ε ,Nb ε )O 12 (where 3≤x−3y−z≤7, 0≤y≤0.2, 0≤z<2.8, and 0.25≤ε≤0.6).

15. The oxide electrolyte sintered body according to claim 10 , wherein the general formula is (Li x−3y−z ,E y ,H z )L α M β O γ (where E is at least one kind of element selected from the group consisting of Al and Ga, 5≤x−3y−z≤7, 0≤y<0.22, 0≤z<2.0, 2.5≤α≤3.5, 1.5≤β≤2.5, and 11≤γ≤13).

Assignees

• Toyota Motor Co Ltd

Inventors

• Yada Chihiro
• Ohta Shingo

Classifications

• C04B2235/5445

  submicron sized, i.e. from 0,1 to 1 micron · CPC title

• C04B35/6455

  Hot isostatic pressing · CPC title

• C04B2235/3281

  Copper oxides, cuprates or oxide-forming salts thereof, e.g. CuO or Cu2O · CPC title

• C04B2235/3244

  Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof · CPC title

• C01P2004/03

  obtained by SEM · CPC title