All-inorganic solvents for electrolytes

• US 10,707,531 B1
• Filed: 09/27/2017
• Issued: 07/07/2020
• Est. Priority Date: 09/27/2016
• Status: Active Grant

• Current Assignee: New Dominion Enterprises, Inc.
• Original Assignee: New Dominion Enterprises, Inc.
• Inventors: Harrup, Mason K., Fraser, Jay
• Primary Examiner(s): Weiner, Laura
• Application Number:
  US15/717,474
• Time in Patent Office: 1,014 Days
• CPC Class Codes: C07F 9/065 Phosphoranes containing the structure P=N-
• CPC Class Codes: C07F 9/65815 n = 3
• CPC Class Codes: C07F 9/659 having three phosphorus atoms as ring hetero atoms in the same ring C07F9/65812 takes precedence
• 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 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 2300/0037 Mixture of solvents
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

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. A solid electrolyte interface layer formed by the electrolyte with an electrode is preferably thermally stable ≥80° C.

Claims

1. An electrolyte solvent formulation comprising:

a phosphoranimine;

a phosphazene present in an amount of between 3 and 30% by volume; and

optionally a monomeric phosphorus compound;

wherein a portion of the electrolyte solvent formulation is labile at a voltage of 5V and the portion is effective to scavenge free radicals and suppress free radical propagation;

being a liquid between at least 0°

C. and 60.6°

C., and having a vapor pressure of combustible components at 60.6°

C. sufficiently low to not produce a combustible mixture in air.

2. The electrolyte solvent formulation according to claim 1, wherein the formulation comprises the monomeric phosphorus compound, selected from the group consisting of a phosphate, phosphonate, phosphinate, phosphine, and a phosphine oxide, having at least two different types of pendent groups, sufficient to achieve a viscosity of the electrolyte solvent formulation of from 1 cp to less than about 30 cp at 35°

C.

3. The electrolyte solvent formulation according to claim 1, wherein the formulation comprises the monomeric phosphorus compound, in an amount of between 10% and 50% by volume, having the structure:

4. The electrolyte solvent formulation according to claim 1, wherein the phosphoranimine has the structure:

5. The electrolyte solvent formulation according to claim 4, wherein R¹, R², and R³ are each independently selected from the group consisting of an alkoxy group, and an aryloxy group.

6. The electrolyte solvent formulation according to claim 1, wherein the phosphazene is a substituted phosphazine having at least two different substituents selected from the group consisting of alkoxy and fluorinated alkoxy groups, and lacking phosphorus-halogen bonds.

7. The electrolyte solvent formulation according to claim 1, wherein the formulation comprises the monomeric phosphorus compound, and

the phosphoranimine is present in an amount of between 20-80% by volume,

and

the monomeric phosphorus compound is present in an amount of 10-80% by volume.

8. A battery, comprising the electrolyte solvent formulation according to claim 1, in combination with an anode, a cathode, a separator, and a supporting salt.

9. The electrolyte solvent formulation according to claim 1, wherein the formulation is substantially free of compounds having any direct halogen-phosphorus bonds.

10. The electrolyte solvent formulation according to claim 1, wherein

the phosphoranimine, the phosphazene, and the monomeric phosphorus compound each lacks phosphorus-halogen bonds, having a stability against degradation under an applied electrical potential of 4 V.