Electrochemical cell

Patent metadata

Field	Value
Publication number	US-11961963-B2
Application number	US-201615575021-A
Country	US
Kind code	B2
Filing date	May 20, 2016
Priority date	May 20, 2015
Publication date	Apr 16, 2024
Grant date	Apr 16, 2024

Abstract

A sodium electrochemical cell that supports a current density at the negative electrode of at least 500 μA/cm 2 , the electrochemical cell comprising (i) a negative electrode and (ii) a sodium-ion ionic liquid electrolyte having a sodium-ion concentration that is no less than 75% of its saturation limit in the electrolyte, wherein the negative electrode has a solid-electrolyte interphase (SEI) layer formed as a result of the electrochemical cell having undergone a polarisation cycle.

First claim

The invention claimed is:

1. A sodium electrochemical cell that supports a current density at the negative electrode of at least 500 μA/cm 2 , the electrochemical cell comprising (i) a negative electrode comprising sodium, and (ii) a sodium-ion ionic liquid electrolyte having a sodium-ion concentration that is no less than 75% of its saturation limit in the electrolyte and is at least 40 mol % wherein the negative electrode has a solid-electrolyte interphase (SEI) layer formed as a result of the electrochemical cell having undergone a polarisation cycle, and wherein the electrolyte comprises a phosphonium-based organic salt.

2. The cell according to claim 1 which supports a current density at the negative electrode of at least 500 μA/cm 2 for at least 20 polarisation cycles.

3. The cell according to claim 1 , wherein the current density at the negative electrode is at least 1,000 μA/cm 2.

4. The cell according to claim 1 , wherein the sodium-ion concentration in the electrolyte is no less than 90% of its saturation limit in the electrolyte.

5. The cell according to claim 1 , wherein the electrolyte comprises Na[TFSI] and [C 3 mpyr][TFSI], Na[TFSI] and [C 4 C 3 pyr][TFSI], Na[TFSI] and [C 3 mpyr][FSI], Na[TFSI] and [C 4 C 3 mpyr][FSI], Na[FSI] and [C 3 mpyr][TFSI], Na[FSI] and [C 4 C 3 mpyr][TFSI], Na[FSI] and [C 3 mpyr][FSI], Na[FSI] and [C 4 C 3 mpyr][FSI], or combinations thereof.

6. The cell according to claim 1 , wherein the electrolyte comprises sodium(bis(fluorosulfonyl)imide (Na[FSI]) and N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (C 3 mpyr[FSI]).

7. The cell according to claim 1 , wherein the negative electrode comprises sodium metal.

8. The cell according to claim 1 , wherein the negative electrode comprises a sodium/carbon composite.

9. The cell according to claim 1 further comprising a counter electrode.

10. The cell according to claim 1 further comprising a positive electrode.

11. The cell according to claim 10 , wherein the positive electrode is a capacitor.

12. A method of manufacturing a sodium electrochemical cell which (i) comprises a negative electrode comprising sodium and a sodium-ion ionic liquid electrolyte having a sodium-ion concentration that is no less than 75% of its saturation limit in the electrolyte and is at least 40 mol %, the electrolyte comprising a phosphonium-based organic salt, and (ii) supports a current density at the negative electrode of at least 500 μA/cm 2 , the method comprising (i) bringing into contact with the negative electrode the sodium-ion ionic liquid electrolyte, and (ii) performing a polarisation cycle of the cell so as to form at the negative electrode a solid-electrolyte interphase (SEI) layer.

13. The method according to claim 12 , wherein the cell further comprises a positive electrode.

14. The method according to claim 12 , wherein the sodium-ion concentration in the electrolyte is no less than 90% of its saturation limit in the electrolyte.

15. The method according to claim 12 , wherein the electrolyte comprises Na[TFSI] and [C 3 mpyr][TFSI], Na[TFSI] and [C 4 C 3 mpyr][TFSI], Na[TFSI] and [C 3 mpyr][FSI], Na[TFSI] and [C 4 C 3 mpyr][FSI], Na[FSI] and [C 3 mpyr][TFSI], Na[FSI] and [C 4 C 3 mpyr][TFSI], Na[FSI] and [C 3 mpyr][FSI], Na[FSI] and [C 4 C 3 mpyr][FSI], or combinations thereof.

16. The method according to claim 12 , wherein the electrolyte comprises sodium(bis(fluorosulfonyl)imide (Na[FSI]) and N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (C 3 mpyr[FSI]).

17. The method according to claim 12 , wherein the negative electrode comprises sodium metal.

18. The method according to claim 13 , wherein the positive electrode is a capacitor.

19. A sodium rechargeable battery that supports a current density at the negative electrode of at least 500 μA/cm 2 , the battery comprising (i) a negative electrode comprising sodium, (ii) a positive electrode and (iii) a sodium-ion ionic liquid electrolyte having a sodium-ion concentration that is no less than 75% of its saturation limit in the electrolyte and is at least 40 mol %, wherein the negative electrode has a solid-electrolyte interphase (SEI) layer formed as a result of the battery having undergone a polarization cycle, and wherein the electrolyte comprises a phosphonium-based organic salt.

Assignees

• Univ Deakin

Inventors

• Howlett Patrick C
• Forsyth Maria
• Macfarlane Douglas Robert
• Yoon Hyun Gook

Classifications

• H01G11/84

  Processes for the manufacture of hybrid or EDL capacitors, or components thereof · CPC title

• H01G11/06

  with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC] · CPC title

• H01M2300/0045

  Room temperature molten salts comprising at least one organic ion · 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