All-inorganic solvents for electrolytes

• US 10,707,526 B2
• Filed: 03/28/2016
• Issued: 07/07/2020
• Est. Priority Date: 03/27/2015
• Status: Active Grant

• Current Assignee: New Dominion Enterprises, Inc.
• Original Assignee: New Dominion Enterprises, Inc.
• Inventors: Harrup, Mason K.
• Primary Examiner(s): Arciero, Adam A
• Application Number:
  US15/082,780
• Publication Number:
  US 20160285125A1
• Time in Patent Office: 1,562 Days
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/056 characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
• CPC Class Codes: H01M 10/0563 Liquid materials, e.g. for Li-SOCl2 cells
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• CPC Class Codes: H01M 2300/002 Inorganic electrolyte
• CPC Class Codes: H01M 2300/0094 in the form of layered products, e.g. coatings
• CPC Class Codes: H01M 4/366 as layered products
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

An all-inorganic electrolyte formulation for use in a lithium ion battery system comprising at least one of each a phosphoranimine, a phosphazene, a monomeric organophosphate and a supporting lithium salt. The electrolyte preferably has a melting point below 0° C., and a vapor pressure of combustible components at 60.6° C. sufficiently low to not produce a combustible mixture in air, e.g., less than 40 mmHg at 30° C. The phosphoranimine, phosphazene, and monomeric phosphorus compound preferably do not have any direct halogen-phosphorus bonds. A solid electrolyte interface layer formed by the electrolyte with an electrode is preferably thermally stable ≥80° C.

Claims

1. An electrolyte for use in a lithium battery, comprising:

lithium ions in an amount of at least 0.1 M;

at least one cyclic phosphazene;

at least one phosphoranimine; and

at least one monomeric phosphorus compound;

wherein the electrolyte;

is a liquid at ≤

0°

C.;

has a viscosity of ≤

30 cp at 35°

C.; and

has a concentration volatile flammable components formed in an air headspace at 30°

C. which is non-flammable.

2. The electrolyte according to claim 1, wherein the at least one cyclic phosphazene is present in an amount of at least 3% and up to 50% by volume.

3. The electrolyte according to claim 2, wherein the at least one phosphoranimine is present in an amount of at least 20% and up to 50% by volume.

4. The electrolyte according to claim 3, wherein the at least one monomeric phosphorus compound is present in an amount of at least 10% and up to 50% by volume.

5. The electrolyte according to claim 1, wherein has a vapor pressure of less than 40 mmHg at 30°

C., a melting point above −

30 C, and a viscosity ≥

1 cp.

6. The electrolyte according to claim 1, wherein the electrolyte consists essentially of compositions lacking direct phosphorus-halogen bonds.

7. The electrolyte according to claim 1, in combination with:

an anode,

a cathode, and

a lithium-ion permeable separator configured to separate the anode and the cathode.

8. The electrolyte according to claim 7, further comprising an electrochemically-formed a solid electrolyte interface layer which stable against degradation at 65°

C.

9. The electrolyte according to claim 1, comprising between 0.1% and 50% by volume of the at least one cyclic phosphazene, between 10% and 50% by volume of the at least one phosphoranimine, and between 10% and 50% by volume of the at least one monophosphorus compound.

10. An electrolyte for use in a lithium battery, which is liquid at 0°

C., comprising;

a supporting lithium salt;

and a solvent comprising;

cyclic phosphazenes in an amount of at least 0.1% and less than 70% by volume;

phosphoranimines in an amount of at least 20% and less than 89.9% by volume; and

monomeric phosphorus compounds in an amount of at least 10% and less that 79.1% by volume;

having a vapor pressure of less than 40 mmHg at 30°

C.

11. The electrolyte of claim 10, wherein the cyclic phosphazenes, phosphoranimines, and monomeric phosphorus compounds each lacks direct phosphorus-halogen bonds.

12. The electrolyte according to claim 10, in combination with:

an anode,

a cathode, and

a separator configured to separate the anode and the cathode and permit lithium ion permeability there-through,

wherein the supporting lithium salt provides a lithium ion concentration of at least 0.2 M, and a solid electrolyte interphase layer selectively forms near a surface of the anode and cathode from degradation products of the electrolyte.

13. The electrolyte of claim 12, wherein a solid electrolyte interface layer formed by the electrolyte with an electrode is thermally stable at ≥

80°

C.

14. The electrolyte of claim 12, wherein the phosphoranimines comprise a plurality of different phosphoranimines, the different phosphoranimines respectively differing by at least having respectfully different substituents.

15. The electrolyte of claim 12, wherein the electrolyte comprises between 3% and 50% of the cyclic phosphazenes by volume and between 20% and 50% of the phosphoranimines by volume.

16. The electrolyte of claim 15, wherein the electrolyte comprises up to 50% by volume of the monomeric phosphorus compounds, and less than 2% purely organic compounds consisting essentially of carbon, hydrogen and oxygen.

17. The electrolyte of claim 10, having a viscosity of ≥

1 cp and ≤

30 cp at 35°

C., a melting point above −

30 C, and a concentration of lithium ions of at least 0.2M.

18. The electrolyte of claim 10, wherein the cyclic phosphazenes comprise a plurality of different cyclic phosphazenes having a plurality of respectfully different substituents.

19. The electrolyte of claim 12, wherein the solid electrolyte interphase layer is stable against degradation at 65°

C.

20. The electrolyte of claim 12, wherein the solid electrolyte interphase layer is stable for at least 245 days at 60°

C.

21. An electrolyte formulation, comprising:

a lithium salt in an amount sufficient to provide at least 0.1 M lithium ions;

a phosphoranimine in an amount of at least 20% and less than or equal to 89.9% by volume;

a cyclic phosphazene in an amount of at least 0.1% and less than or equal to 70% by volume; and

a monomeric phosphorus compound in an amount of at least 10% and less than or equal to 79.9% by volume;

the formulation having;

a viscosity of ≤

30 cp at 35°

C., a melting point below 0°

C., and a vapor pressure of ≤

40 mmHg at 30°

C., wherein none of the phosphoranimine, cyclic phosphazene, and monomeric phosphorus compound has any direct halogen-phosphorus bonds.

22. The formulation of claim 21, wherein the supporting salt comprises LiPF₆.

23. The formulation of claim 21, wherein the monomeric phosphorus compound is selected from the group consisting of a phosphate, phosphonate, phosphinate, phosphine, and a phosphine oxide, having at least two different types of pendent groups.

24. The formulation of claim 21, wherein the phosphoranimine has the structure:

25. The formulation of claim 24, wherein X is selected from the group consisting of an organosilyl group and a tert-butyl group and R¹, R², and R³ are independently selected from the group consisting of a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted aryloxy group.

26. The formulation of claim 21, wherein the cyclic phosphazene comprises a plurality of cyclic phosphazenes having respectively different pendent group substitution, having substituents selected from the group consisting of alkoxy groups and fluorinated alkoxy groups.

27. The formulation of claim 21, comprising less than 2% by weight of organic compounds consisting essentially of at least one of carbon, hydrogen, and oxygen.

28. The formulation of claim 21, wherein the phosphoranimine is present in an amount of between 20-50% by volume, the cyclic phosphazene is present in an amount of between 3-15% by volume, and the monomeric phosphorus compound is present in an amount of 20-50% by volume, the formulation has a viscosity of at least 1 cp, and a melting point of at least −

30 C.

29. A battery comprising the formulation of claim 21, in combination with an anode, a cathode, and a separator.