Multifunctional hybrid coatings for electrodes made by atomic layer deposition techniques

Patent metadata

Field	Value
Publication number	US-9531004-B2
Application number	US-201314138267-A
Country	US
Kind code	B2
Filing date	Dec 23, 2013
Priority date	Dec 23, 2013
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

An electroactive material for use in an electrochemical cell, like a lithium ion battery, is provided. The electroactive material comprises a multifunctional hybrid protective coating system formed over an electroactive material. The coating system includes a first oxide-based coating disposed on one or more surfaces of the electroactive material, followed by a second coating deposited via a non-aqueous process. The second coating may be a fluoride-based, nitride-based, or carbide-based coating. The first and second coatings may be applied by atomic layer deposition (ALD) to form conformal ultrathin layers over the electroactive materials. Such a multifunctional hybrid protective coating system can suppress formation of gases within the electrochemical cell and also minimize formation of solid electrolyte interface (SEI) layers on the electrode to improve battery performance. Methods for making such materials and using such materials in electrochemical cells are likewise provided.

First claim

What is claimed is:

1. An electrode for an electrochemical cell comprising:
an electroactive material;
a first oxide-based coating formed on one or more surface regions of the electroactive material; and
a conformal second coating disposed over the entire first oxide-based coating, wherein the conformal second coating is distinct from the first oxide-based coating and is formed from a non-aqueous coating process.

2. The electrode of claim 1 , wherein the first oxide-based coating comprises an oxide of a metal selected from the group consisting of: titanium (Ti), aluminum (Al), tin (Sn), vanadium (V), hafnium (Hf), zirconium (Zr), zinc (Zn) and combinations thereof.

3. The electrode of claim 1 , wherein the first oxide-based coating is selected from the group consisting of: aluminum oxide, silicon dioxide, tin dioxide, titanium dioxide, vanadium pentoxide, hafnium dioxide, zirconium dioxide, and zinc oxide.

4. The electrode of claim 1 , wherein the second coating is selected from the group consisting of: a fluoride-based coating, a carbide-based coating, and a nitride-based coating.

5. The electrode of claim 1 , wherein the second coating is a fluoride-based coating.

6. The electrode of claim 5 , wherein the first oxide-based coating comprises aluminum oxide.

7. The electrode of claim 1 , wherein the electroactive material is selected from the group consisting of: lithium titanate Li (4+x) Ti 5 O 12 , where 0≦x≦3 (LTO), graphite, silicon, silicon-containing alloys, tin-containing alloys, and combinations thereof.

8. The electrode of claim 1 , wherein a thickness of the first oxide-based coating is less than or equal to about 5 nm and a thickness of the second coating is less than or equal to about 50 nm.

9. The electrode of claim 1 , wherein a thickness of the first oxide-based coating is less than or equal to about 15 nm and a thickness of the second coating is less than or equal to about 5 nm.

10. A lithium ion electrochemical cell comprising:
the electrode of claim 1 used as a negative electrode;
a positive electrode;
a separator; and
an electrolyte; wherein the lithium ion electrochemical cell is capable of maintaining charge capacity for greater than or equal to about 500 hours of operation.

11. A method of making an electrode for an electrochemical cell, the method comprising:
applying a first oxide-based coating via a deposition process to one or more surface regions of an electroactive material; and
applying a conformal second coating over the entire first oxide-based coating via a non-aqueous coating process, wherein the second coating is selected from the group consisting of: a fluoride-based coating, a carbide-based coating, and a nitride-based coating.

12. The method of claim 11 , wherein the first oxide-based coating has a thickness of less than or equal to about 5 nm and the second coating has a thickness of less than or equal to about 50 nm.

13. The method of claim 11 , wherein the non-aqueous coating process for applying the second coating is selected from the group consisting of: atomic layer deposition (ALD), physical vapor deposition (PVD), chemical vapor deposition (CVD), chemical vapor infiltration, non-aqueous wet chemistry, and non-aqueous sol-gel.

14. The method of claim 11 , wherein the non-aqueous coating process is a non-aqueous atomic layer deposition process using a precursor selected from the group consisting of: lithium fluoride (LiF), aluminum fluoride (AlF 3 ), titanium carbide (TiC), silicon carbide (SiC), tungsten carbide (WC), titanium nitride (TiN), aluminum nitride (AlN), vanadium nitride (VN), and combinations thereof.

15. The method of claim 11 , wherein the deposition process for applying the first oxide-based coating is atomic layer deposition (ALD) that uses a trimethyl aluminum ((CH 3 ) 3 Al) precursor to form an aluminum oxide coating on the electroactive material and the second coating is a fluoride-based coating applied with a precursor material selected from the group consisting of: lithium fluoride (LiF), aluminum fluoride (AlF 3 ), and combinations thereof.

16. The method of claim 11 , wherein the electroactive material is a negative electroactive material selected from the group consisting of: lithium titanate Li (4+x) Ti 5 O 12 , where 0≦x≦3 (LTO), graphite, silicon, silicon-containing alloys, tin-containing alloys, and combinations thereof.

17. The electrode of claim 1 , wherein the electroactive material is contained in a pre-fabricated electrode layer and the first oxide-based coating and the conformal second coating are applied to at least one surface of the pre-fabricated electrode layer and applied so as to cover the one or more surface regions of the electroactive material.

18. The electrode of claim 1 , wherein the electroactive material is in the form of a plurality of particles.

19. The electrode of claim 1 , further comprising a plurality of carbon black particles and one or more polymeric binders.

20. An electrode for an electrochemical cell comprising:
an electroactive material comprising lithium titanate Li (4+x) Ti 5 O 12 , where 0≦x≦3 (LTO);
a first oxide-based coating formed on one or more surface regions of the electroactive material that may contact an electrolyte or a solvent in the electrochemical cell; and
a conformal second coating disposed over the entire first oxide-based coating, wherein the conformal second coating is distinct from the first oxide-based coating and is formed from a non-aqueous coating process.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Xiao Xingcheng
• Verbrugge Mark W
• Wang John S

Classifications

• H01M4/625

  Carbon or graphite · CPC title

• Y02P70/54

  Cross-Sectional Technologies · mapped topic

• H01M4/0402

  Methods of deposition of the material · CPC title

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title