Method of preparing a water-reactive sulfide material

Patent metadata

Field	Value
Publication number	US-11542161-B2
Application number	US-202117177988-A
Country	US
Kind code	B2
Filing date	Feb 17, 2021
Priority date	Feb 17, 2020
Publication date	Jan 3, 2023
Grant date	Jan 3, 2023

Abstract

A process for producing a low-cost water-reactive metal sulfide material includes dissolving a substantially anhydrous alkali metal salt and a substantially anhydrous sulfide compound in a substantially anhydrous polar solvent, providing differential solubility for a substantially high solubility alkali metal sulfide and a substantially low solubility by-product, and forming a mixture of the high solubility alkali metal sulfide and the low solubility by-product; separating the low solubility by-product from the mixture to isolate the supernatant including the alkali metal sulfide, and separating the polar solvent from the alkali metal sulfide to produce the alkali metal sulfide. The present invention provides a scalable process for production of a high purity alkali metal sulfide that is essentially free of undesired by-products.

First claim

What is claimed is:

1. A method for producing a water-reactive alkali metal sulfide compound comprising:
dissolving a substantially anhydrous alkali metal salt precursor and a substantially anhydrous sulfide precursor compound in one or more substantially anhydrous polar solvents, wherein the polar solvent provides differential solubility for a high solubility alkali metal sulfide and a low solubility by-product;
forming a mixture comprising a supernatant of the high solubility alkali metal sulfide dissolved in the polar solvent, and a precipitate of the low solubility by-product;
separating the precipitate of the low solubility by-product from the supernatant;
evaporating the polar solvent from the supernatant; and a final heat treatment to isolate the alkali metal sulfide.

2. The method of claim 1 , further comprising addition of a sulfur source at any point during the process to increase the purity of the final alkali metal sulfide product.

3. The method of claim 2 , the sulfur source comprising one or more of elemental sulfur and H 2 S.

4. The method of claim 2 , wherein the sulfur source is added to one or more of the sulfide precursor solution, the alkali metal salt precursor solution, the combined sulfide and alkali metal salt mixture, and the isolated alkali metal sulfide prior to heat treatment.

5. The method of claim 2 , wherein the isolated alkali metal sulfide material further comprises a Li 3 OCl phase which may be subsequently removed following the sulfur source addition and a subsequent heat treatment step.

6. The method of claim 1 , further comprising introducing an anti-solvent compound to the supernatant of the high solubility alkali metal sulfide and the polar solvent, directly following the precipitation of the low solubility by-product.

7. The method of claim 6 , wherein the anti-solvent is selected from one or more of heptane and other non-polar solvents with substantial miscibility in the polar solvent and which increases the differential solubility of the alkali metal sulfide versus the by-products.

8. The method of claim 1 , wherein separating the low solubility by-product from the supernatant further comprises at least one of centrifuging, filtering, gravity settling, and cooling.

9. The method of claim 1 , wherein separating the polar solvent from the supernatant further comprises at least one of evaporating the polar solvent, recrystallization, and heating under vacuum.

10. The method of claim 1 , further comprising adjusting the relative amounts of the alkali metal salt precursor and the sulfide precursor compound added to the solution to adjust the purity of the resultant alkali metal sulfide.

11. The method of claim 10 , wherein the resultant alkali metal sulfide material further comprises alkali metal salt precursor.

12. The method of claim 1 , wherein the substantially anhydrous polar solvent is at least one alcohol selected from the group consisting of ethanol, 1-propanol, 1-butanol, ethanol denaturing agents and mixtures thereof.

13. The method of claim 1 , wherein the alkali metal salt precursor is LiCl.

14. The method of claim 1 , wherein the alkali metal salt precursor and the sulfide precursor compound are independently dissolved in the polar solvent prior to forming of a combined mixture.

15. The method of claim 1 , wherein one of the alkali metal salt precursor and the sulfide precursor compound is dissolved in the polar solvent and the other is added to the solution in solid form.

16. The method of claim 1 , wherein the ratio of the solubility of the alkali metal sulfide to the solubility of the by-product in the polar solvent is at least 90:10.

17. The method of claim 1 , wherein the ratio of the solubility of the alkali metal sulfide to the solubility of the by-product in the polar solvent is at least 97:3.

18. The method of claim 1 , wherein the ratio of the solubility of the alkali metal sulfide to the solubility of the by-product in the polar solvent is at least 99:1.

19. The method of claim 1 , wherein the ratio of the solubility of the alkali metal sulfide to the solubility of the by-product in the polar solvent is at least 99.9:0.1.

20. The method of claim 1 , wherein the sulfide precursor compound is selected from the group consisting of K 2 S, Na 2 S, and (NH 4 ) 2 S.

21. The method of claim 1 , wherein the alkali metal sulfide is Li 2 S.

22. The method of claim 1 , further comprising drying the resultant alkali metal sulfide.

23. A solid electrolyte comprising the water-reactive alkali metal sulfide produced by the method of claim 1 .

24. The solid state electrolyte of claim 23 , wherein the alkali metal sulfide is Li 2 S.

25. A solid electrolyte comprising the material comprising alkali metal sulfide and alkali metal salt produced by the method of claim 11 .

26. The solid state electrolyte of claim 25 , wherein the alkali metal sulfide is Li 2 S and the alkali metal salt is one or more of LiCl and LiBr.

27. A solid state battery comprising the water-reactive alkali metal sulfide produced by the method of claim 1 .

28. The solid state battery of claim 27 , wherein the alkali metal sulfide is Li 2 S.

29. A vehicle powered by a battery comprising the water-reactive alkali metal sulfide produced by the method of claim 1 .

30. The vehicle of claim 29 , wherein the alkali metal sulfide is Li 2 S.

31. A method for producing lithium sulfide comprising:
dissolving substantially anhydrous LiCl and a substantially anhydrous sulfide compound selected from Na 2 S and K 2 S in a solvent selected from ethanol, 1-propanol and 1-butanol;
precipitating the solution to form a supernatant of high solubility Li 2 S alkali metal sulfide and the solvent, and a precipitate of low solubility chloride by-product;
separating the low solubility by-product from the supernatant; and
evaporating the solvent from the supernatant to isolate Li 2 S.

32. The method of claim 31 , further comprising the addition of a sulfur source.

33. The method of claim 32 , the sulfur source comprising one or more of elemental sulfur and H 2 S.

34. The method of claim 31 , further comprising introducing an anti-solvent compound to the supernatant of the high solubility alkali metal sulfide and the polar solvent, directly following the precipitation of the low solubility by-product, wherein the anti-solvent is selected from one or more of heptane and other non-polar solvents with substantial miscibility in the polar solvent and which increases the differential solubility of the alkali metal sulfide versus the by-products.

Assignees

• Solid Power Inc
• Solid Power Operating Inc

Inventors

• Lisenker Ilya
• Culver Sean

Classifications

• C01B17/22 Primary

  Alkali metal sulfides or polysulfides · CPC title

• H01M10/0562

  Solid materials · CPC title

• C01P2006/90

  Other properties not specified above · CPC title

• H01M2300/0068

  inorganic · CPC title

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title