Metal fluoride passivation coatings prepared by atomic layer deposition for Li-ion batteries

Patent metadata

Field	Value
Publication number	US-10177365-B2
Application number	US-201514693719-A
Country	US
Kind code	B2
Filing date	Apr 22, 2015
Priority date	Mar 5, 2015
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

The fabrication of robust interfaces between transition metal oxides and non-aqueous electrolytes is one of the great challenges of lithium ion batteries. Atomic layer deposition (ALD) of aluminum tungsten fluoride (AlWxFy) improves the electrochemical stability of LiCoO2. AlWxFy thin films were deposited by combining trimethylaluminum and tungsten hexafluoride. in-situ quartz crystal microbalance and transmission electron microscopy studies show that the films grow in a layer-by-layer fashion and are amorphous nature. Ultrathin AlWxFy coatings (<10 Å) on LiCoO2 significantly enhance stability relative to bare LiCoO2 when cycled to 4.4 V. The coated LiCoO2 exhibited superior rate capability (up to 400 mA/g) and discharge capacities at a current of 400 mA/g were 51% and 92% of the first cycle capacities for the bare and AlWxFy coated materials. These results open new possibilities for designing ultrathin and electrochemically robust coatings of metal fluorides via ALD to enhance the stability of Li-ion electrodes.

First claim

What is claimed is:

1. A method of preparing a metal fluoride passivation coating on a cathode comprising:
performing a atomic layer deposition cycles of TMA at a first deposition temperature between 50° C. and 300° C.; and
performing b atomic layer deposition cycles of WF 6 at a second deposition temperature between 50° C. and 300° C., and
forming a layer consisting of AlW x F y C z on the cathode such that the layer excludes oxygen, where x>0, y>0, and z≥0.

2. The method of claim 1 , wherein the ratio of a:b is selected from the group consisting of 3:1, 2:1, 1:1, and 4:2.

3. The method of claim 1 , wherein the first deposition temperature and the second deposition temperature are about 200° C.

4. The method of claim 1 , wherein the cathode comprises LiCoO 2 .

5. The method of claim 1 , wherein z>0.

6. The method of claim 1 , wherein the AlW x F y C z layer has a thickness of less than about 1 nm.

7. The method of claim 1 , wherein the a cycles each comprise: a 1 second TMA dose followed by a 5 second gas purge.

8. The method of claim 1 , wherein the b cycle depositions each comprise: a 1 second WF 6 dose followed by a 5 second gas purge.

9. The method of claim 1 , wherein the metal fluoride passivation coating comprises particles of WC z , wherein z≥0, disposed in a matrix of AlF 3 .

Assignees

• Uchicago Argonne Llc

Inventors

• Mane Anil U
• Elam Jeffrey W
• Park Joong Sun
• Croy Jason R

Classifications

• C23C16/30

  Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/628

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

• H01M4/1391

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title