Electrolyte material having a NASICON structure for solid-state sodium ion batteries and method for the production thereof

Patent metadata

Field	Value
Publication number	US-10566654-B2
Application number	US-201615758345-A
Country	US
Kind code	B2
Filing date	Aug 27, 2016
Priority date	Oct 9, 2015
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

A method for preparing electrolyte material having a NASICON structure, based on a Na 3+x Sc x Zr 2−x (SiO 4 ) 2 (PO 4 ) compound where 0≤x<2. The method includes providing an acidic, aqueous solution which, according to a desired stoichiometry, comprises sodium, scandium and zirconium in the form of water-soluble nitrates, acetates or carbonates, and soluble silicates or orthosilicic acids or organic silicon compounds in dissolved form; subsequently adding phosphoric acid or ammonium dihydrogenphosphate or other soluble phosphates, according to the desired stoichiometry, complex zirconium dioxide phosphates forming as colloidal precipitations; and subsequently drying and calcining the mixture.

First claim

The invention claimed is:

1. A method for preparing electrolyte material having a NASICON structure, based on a Na 3 Zr 2 (SiO 4 ) z (PO 4 ) 3 compound where 0≤x<2, comprising the steps of:
providing an acidic, aqueous solution which, according to a desired stoichiometry, comprises sodium, scandium and zirconium in the form of water-soluble nitrates, acetates or carbonates, and soluble silicates or orthosilicic acids or organic silicon compounds in dissolved form as starting materials;
subsequently adding phosphoric acid or ammonium dihydrogenphosphate or other soluble phosphates, according to the desired stoichiometry, thereby forming a mixture having complex zirconium dioxide phosphates as colloidal precipitations; and
subsequently drying and calcining the mixture.

2. The method according to claim 1 , wherein the starting materials are selected according to the stoichiometry for 0≤x<2.

3. The method according to claim 1 , wherein the mixture is dried at temperatures of between 60° C. and 120° C.

4. The method according to claim 1 , wherein the mixture is calcined at temperatures of between 700° C. and 900° C.

5. The method according to claim 1 , wherein, the dried and calcined mixture comprises particles having a particle size, determined using a scanning electron microscope, of approximately 0.1 μm.

6. The method according to claim 1 , wherein the dried and calcined mixture is subsequently ground.

7. The method according to claim 6 , wherein the dried, calcined and ground mixture is subsequently compressed.

8. The method according to claim 7 , wherein the dried, calcined and ground mixture is compressed at pressures of between 50 and 100 MPa.

9. The method according to claim 7 , wherein the compressed mixture is sintered at temperatures of between 1200° and 1300° C.

10. A sodium ion-conducting membrane comprising a Na 3 Zr 2 (SiO 4 ) z (PO 4 ) 3 compound where 0.3≤x≤0.6, which can be prepared according to claim 1 , having an ionic conductivity of more than 1.2·10 −3 S/cm at 25° C.

11. A sodium ion-conducting membrane according to claim 10 , having a density of more than 90% of a theoretical density.

12. A sodium ion-conducting membrane comprising a Na 3 Zr 2 (SiO 4 ) z (PO 4 ) 3 compound where 0.3≤x≤0.6, which can be prepared according to claim 1 , having an ionic conductivity of more than 3·10 −3 S/cm at 25° C.

13. A sodium ion-conducting membrane according to claim 12 , having a density of more than 90% of a theoretical density.

Assignees

• Forschungszentrum Juelich Gmbh

Inventors

• Ma Qianli
• Tietz Frank
• Naqash Sahir
• Guillon Olivier

Classifications

• C01B33/32

  Alkali metal silicates ({C01B33/24} , C01B33/26 take precedence) · CPC title

• C04B35/645

  Pressure sintering · CPC title

• C04B2235/3201

  Alkali metal oxides or oxide-forming salts thereof · CPC title

• C01B25/26

  Phosphates (perphosphates C01B15/16) · CPC title

• H01M10/0585

  of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators · CPC title