Low temperature lithium production

Patent metadata

Field	Value
Publication number	US-11466376-B1
Application number	US-202016908916-A
Country	US
Kind code	B1
Filing date	Jun 23, 2020
Priority date	Mar 19, 2018
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

A method and electrolysis cell for producing lithium metal at a low temperature. The method includes combining (i) acetonitrile and (ii) a cation bis(trihaloalkylsulfonyl)imide, cation bis(trihalosulfonyl)imidic acid, a cation bis(trihaloalkylsulfonyl)amide, or cation bis(trihaloalkylsulfonyl)amidic acid in a weight ratio of (i) to (ii) about 100:1 to about 5:1 to provide a non-aqueous electrolyte composition. A lithium compound selected from the group consisting of LiOH, Li2O and Li2CO3 is dissolved in the electrolyte composition to provide a lithium doped electrolyte composition. Power is applied to the electrolyte composition to form lithium metal on a cathode of an electrolysis cell. The lithium metal separated from the cathode has a purity of at least about 95 wt. %.

First claim

What is claimed is:

1. A method of producing lithium metal in an electrolysis cell, the method comprising the steps of:
combining (i) acetonitrile and (ii) a cation bis(trihaloalkylsulfonyl)imide, a cation bis(trihalo-sulfonyl)imidic acid, a cation bis(trihaloalkylsulfonyl)amide, or a cation bis(trihaloalkylsulfonyl)amidic acid in a weight ratio of (i) to (ii) of about 100:1 to about 5:1 to provide a non-aqueous electrolyte composition,
dissolving a lithium compound selected from the group consisting of LiOH, Li 2 O and Li 2 CO 3 in the non-aqueous electrolyte composition to provide a doped lithium electrolyte composition,
applying power to the electrolysis cell to form lithium metal on a cathode of an electrolysis cell, and
separating lithium metal from the cathode, wherein the lithium metal on the cathode has a purity of at least about 95 wt. %.

2. The method of claim 1 , wherein the doped lithium electrolyte composition further comprises a zwitterion or internal salt compound.

3. The method of claim 2 , wherein the zwitterion comprises a (carboxyalkyl)trialkyl ammonium compound.

4. The method of claim 1 , wherein the weight ratio of (i) to (ii) of the non-aqueous electrolyte composition is about 20:1 to 10:1.

5. The method of claim 1 , wherein a weight ratio of non-aqueous electrolyte composition to lithium compound ranges from about 5:1 to about 2:3.

6. The method of claim 1 , wherein a weight ratio of non-aqueous electrolyte composition to lithium compound ranges from about 3:1 to about 3:4.

7. The method of claim 1 , wherein the doped lithium electrolyte composition is at a temperature ranging from about 0° to less than about 180° C.

8. The method of claim 1 , wherein the doped lithium electrolyte composition is at a temperature ranging from about 0° to less than about 100° C.

9. The method of claim 1 , wherein the doped lithium electrolyte composition is at a temperature ranging from about 15° to less than about 81° C.

10. The method of claim 1 , wherein the electrolysis cell contains a cover gas above the doped lithium electrolyte composition.

11. The method of claim 1 , wherein the electrolysis cell comprises an anode compartment, a cathode compartment and a separator between the anode compartment and the cathode compartment.

12. The method of claim 11 , wherein the separator is selected from the group consisting of a fritted glass separator, a microporous membrane, and a salt bridge.

13. The method of claim 1 , wherein the cation is selected from the group consisting of a phosphonium ion, a sulfonium ion, an ammonium ion, an imidazolium ion, a piperidinium ion, a pyridinium ion and a pyrrolidinium ion.

14. The method of claim 1 , wherein the cation is selected from the group consisting of an alkali metal, an alkaline earth metal, a metalloid, a transition metal, and a lanthanide.

15. The method of claim 1 , wherein the halo ion is a fluoride ion.

16. The method of claim 1 , wherein the alkyl group is a methyl group.

17. The method of claim 1 , wherein power is applied to the anode and cathode at a current density ranging from about 0.1 mA/cm 2 to about 2.5 mA/cm 2 .

18. An electrolysis cell for producing lithium metal at a temperature comprising:
a cathode compartment comprising a cathode,
an anode compartment comprising an anode,
a separator between the anode compartment and the cathode compartment,
a non-aqueous electrolyte composition in the anode and cathode compartments comprising (i) acetonitrile and (ii) a cation bis(trihaloalkylsulfonyl)imide, a cation bis(trihalosulfonyl)imidic acid, a cation bis(trihaloalkylsulfonyl)amide, or a cation bis(trihaloalkylsulfonyl)amidic acid in a weight ratio of (i) to (ii) of about 100:1 to about 5:1, wherein the electrolyte composition further comprises a lithium compound selected from the group consisting of LiOH, Li 2 O and Li 2 CO 3 dissolved in the electrolyte composition, and wherein the separator is selected from the group consisting of a fritted glass separator, a microporous membrane, and a salt bridge,

whereby power applied to the anode and cathode forms lithium metal on the cathode of the electrolysis cell with a lithium metal purity of greater than 95 wt. %.

19. The electrolysis cell of claim 18 , wherein a weight ratio of non-aqueous electrolyte composition to lithium compound ranges from about 5:1 to about 2:3.

20. The electrolysis cell of claim 18 , wherein the electrolyte composition further comprises a (carboxyalkyl)trialkyl ammonium compound.

21. The electrolysis cell of claim 18 , wherein the cation is selected from the group consisting of a phosphonium ion, a sulfonium ion, an ammonium ion, an imidazolium ion, a piperidinium ion, a pyridinium ion, and a pyrrolidinium ion.

22. The electrolysis cell of claim 18 , wherein the cation is selected from the group consisting of an alkali metal, an alkaline earth metal, a metalloid, a transition metal, and a lanthanide.

23. The electrolysis cell of claim 18 , wherein the halo ion is a fluoride ion.

24. The electrolysis cell of claim 18 , wherein the alkyl group is a methyl group.

25. The electrolysis cell of claim 18 , wherein the electrolysis cell temperature is below about 180° C.

26. The electrolysis cell of claim 18 , wherein the electrolysis cell contains a cover gas above the lithium compound dissolved in the electrolyte composition.

Assignees

• Cons Nuclear Security Llc

Inventors

• Freiderich John W

Classifications

• C25C7/025

  used in cells for the electrolysis of melts · CPC title

• C25C1/02

  of light metals · CPC title

• C25C3/02 Primary

  of alkali or alkaline earth metals · CPC title

• C25C7/005

  of cells for the electrolysis of melts (C25C7/02 - C25C7/06 take precedence) · CPC title