Mobile layer of ionic liquid in electrolytes

Patent metadata

Field	Value
Publication number	US-10910671-B2
Application number	US-201916565500-A
Country	US
Kind code	B2
Filing date	Sep 10, 2019
Priority date	Apr 7, 2016
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

Electrolytes, anodes, lithium ion cells and methods are provided for preventing lithium metallization in lithium ion batteries to enhance their safety. Electrolytes comprise up to 20% ionic liquid additives which form a mobile solid electrolyte interface during charging of the cell and prevent lithium metallization and electrolyte decomposition on the anode while maintaining the lithium ion mobility at a level which enables fast charging of the batteries. Anodes are typically metalloid-based, for example include silicon, germanium, tin and/or aluminum. A surface layer on the anode bonds, at least some of the ionic liquid additive to form an immobilized layer that provides further protection at the interface between the anode and the electrolyte, prevents metallization of lithium on the former and decomposition of the latter.

First claim

We claim:

1. A method for reducing metallization in a lithium ion battery, comprising:
adding, into a carbonate-containing electrolyte of the lithium ion battery, up to 10 percent by volume of at least one ionic liquid, which consists of cations and anions,
forming, during charging of the lithium ion battery and at surfaces of anode material particles thereof, a mobile layer comprising at least some of the cations, and
configuring the formed mobile layer to fill in cracks in the anode material particles.

2. The method of claim 1 , comprising coating the anode material particles with a coating that binds at least some of the cations of the mobile layer.

3. The method of claim 1 , further comprising selecting the cations and/or anions to be at least 50% larger in volume than lithium ions, preventing lithium metallization at the anode material particles by steric hindrance.

4. The method of claim 1 , further comprising selecting the cations and anions to have molecular shapes that prevent, by steric hindrance, lithium metallization on the anode material particles.

5. The method of claim 1 , further comprising selecting the at least one ionic liquid to have a melting temperature below 0° C.

6. The method of claim 1 , further comprising selecting the cations to comprise at least one piperidinium, substituted or unsubstituted.

7. The method of claim 1 , further comprising selecting the anions to comprise at least one sulfonylimide, substituted or unsubstituted.

8. A method for reducing metallization in a lithium ion battery, comprising:
adding, into a carbonate-containing electrolyte of the lithium ion battery, up to 10 percent by volume of at least one ionic liquid, which consists of cations and anions,
forming, during charging of the lithium ion battery and at surfaces of anode material particles thereof, a mobile layer comprising at least some of the cations; and
establishing a gradient of electric charge at the mobile layer during charging of the lithium ion battery, to provide an interphase transition between the electrolyte and the anode material particles, the gradient configured to have a gradual change of parameters which gradually reduces an activation energy of a reduction reaction of lithium ions being charged from the electrolyte into the anode material particles.

9. The method of claim 1 , wherein the adding comprises less than 5 percent by volume of the at least one ionic liquid, added into the carbonate-containing electrolyte.

10. The method of claim 8 , comprising configuring the formed mobile layer to fill in cracks in the anode material particles.

11. The method of claim 1 , further comprising producing the anode material particles from Ge, Si and/or Sn.

12. The method of claim 1 , further comprising preparing the lithium ion battery with the carbonate-containing electrolyte and anodes made of the anode material particles and operating the prepared lithium ion battery through at least one cycle, to carry out the forming of the mobile layer controllably.

13. A method for reducing metallization in a lithium ion battery, comprising:
adding, into a carbonate-containing electrolyte of the lithium ion battery, up to 10 percent by volume of at least one ionic liquid, which consists of cations and anions,
forming, during charging of the lithium ion battery and at surfaces of anode material particles thereof, a mobile layer comprising at least some of the cations; and
coating the anode material particles with a coating that binds at least some of the cations of the mobile layer.

14. The method of claim 13 , wherein the coating comprises at least one lithium sulfonate, substituted or unsubstituted.

15. The method of claim 13 , comprising establishing a gradient of electric charge at the mobile layer during charging of the lithium ion battery, to provide an interphase transition between the electrolyte and the anode material particles, the gradient configured to have a gradual change of parameters which gradually reduces an activation energy of a reduction reaction of lithium ions being charged from the electrolyte into the anode material particles.

16. The method of claim 13 , further comprising selecting the cations and/or anions to be at least 50% larger in volume than lithium ions, preventing lithium metallization at the anode material particles by steric hindrance.

17. The method of claim 13 , further comprising preparing the lithium ion battery with the carbonate-containing electrolyte and anodes made of the anode material particles and operating the prepared lithium ion battery through at least one cycle, to carry out the forming of the mobile layer controllably.

18. The method of claim 13 , further comprising selecting the cations and anions to have molecular shapes that prevent, by steric hindrance, lithium metallization on the anode material particles.

19. The method of claim 8 , further comprising selecting the cations and/or anions to be at least 50% larger in volume than lithium ions, preventing lithium metallization at the anode material particles by steric hindrance.

20. The method of claim 8 , further comprising preparing the lithium ion battery with the carbonate-containing electrolyte and anodes made of the anode material particles and operating the prepared lithium ion battery through at least one cycle, to carry out the forming of the mobile layer controllably.

21. The method of claim 8 , further comprising selecting the cations and anions to have molecular shapes that prevent, by steric hindrance, lithium metallization on the anode material particles.

Assignees

• Storedot Ltd

Inventors

• Burshtain Doron
• Kedem Nir
• Aronov Daniel

Classifications

• H01M4/628

  Inhibitors, e.g. gassing inhibitors, corrosion inhibitors · CPC title

• H01M2300/0025

  Organic electrolyte · CPC title

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M4/5815

  Sulfides · CPC title

• H01M4/602

  Polymers · CPC title