Sodium electrochemical interfaces with NaSICON-type ceramics

Patent metadata

Field	Value
Publication number	US-11545723-B2
Application number	US-202017104306-A
Country	US
Kind code	B2
Filing date	Nov 25, 2020
Priority date	Nov 26, 2019
Publication date	Jan 3, 2023
Grant date	Jan 3, 2023

Abstract

The present invention is directed to the modification of sodium electrochemical interfaces to improve performance of NaSICON-type ceramics in a variety of electrochemical applications. Enhanced mating of the separator-sodium interface by means of engineered coatings or other surface modifications results in lower interfacial resistance and higher performance at increased current densities, enabling the effective operation of molten sodium batteries and other electrochemical technologies at low and high temperatures.

First claim

We claim:

1. A method for improving a sodium electrochemical interface, comprising:
providing a sodium-ion conducting NaSICON-type ceramic having a surface, wherein the NaSICON-type ceramic comprises a three-dimensional hexagonal framework of corner-sharing oxide tetrahedra and octahedra having the basic formula A 1+x+y M′ x M 2−x B y B′ 3−y O 12 , wherein A is a sodium ion occupying interstitial sites, M and M′ are multivalent transition metal cations occupying octahedral sites, and B and B′ typically are silicon and phosphorous occupying tetrahedral sites, and wherein 0≤x≤2 and 0≤y≤3;
depositing a coating comprising tin, bismuth, lead, or antimony on the surface of the NaSICON-type ceramic; and
forming a sodium ion-conducting sodium-tin, sodium-bismuth, sodium-lead, or sodium-antimony intermetallic phase on the surface of the NaSICON-type ceramic by sodium electrochemical cell cycling at a temperature below the melting temperature of tin, bismuth, lead, or antimony, respectively, thereby providing a sodium electrochemical interface with improved sodium ion conduction from a sodium source through the NaSICON-type ceramic.

2. The method of claim 1 , wherein the NaSICON-type ceramic comprises Na 1+y Zr 2 Si y P 3−y O 12 , wherein 0≤y≤3.

3. The method of claim 1 , wherein the sodium source comprises sodium metal or a sodium metal alloy.

4. The method of claim 1 , wherein the thickness of the tin coating is greater than a critical thickness at which tin, bismuth, lead, or antimony, respectively, exceeds its solubility limit in molten sodium.

5. The method of claim 1 , wherein tin, bismuth, lead, or antimony, respectively, is insoluble or sparingly soluble in sodium at a temperature at which the intermetallic phase forms.

6. The method of claim 1 , wherein the step of forming comprises coating the surface of the NaSICON-type ceramic with an oxide of a metal, metalloid, or alloy thereof, and forming the intermetallic phase with sodium at a temperature below the melting temperature of the oxide.

7. The method of claim 6 , wherein the oxide comprises Sb 2 O 3 or GeO 2 .

8. The method of claim 1 , wherein the step of forming comprises coating the surface of the NaSICON-type ceramic with a chalcogenide of a metal, metalloid, or alloy thereof, and forming the intermetallic phase with sodium at a temperature below the melting temperature of the chalcogenide.

9. The method of claim 1 , wherein the sodium electrochemical interface operates at a temperature less than 200° C.

10. The method of claim 1 , wherein the sodium electrochemical interface operates at a temperature greater than 200° C.

11. The method of claim 3 , wherein the sodium metal or sodium metal alloy is molten.

12. The method of claim 3 , wherein the sodium metal or sodium metal alloy is solid.

Assignees

• Nat Tech & Eng Solutions Sandia Llc

Inventors

• Spoerke Erik David
• Gross Martha
• Percival Stephen
• Rodriguez Mark A
• Small Leo J

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M50/449 Primary

  having a layered structure · CPC title

• H01M50/434 Primary

  Ceramics · CPC title

• H01M10/054

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

• H01M4/381

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