Process for the preparation of an electrode from a porous material, electrode thus obtained and corresponding electrochemical system

Patent metadata

Field	Value
Publication number	US-9768441-B2
Application number	US-201414479815-A
Country	US
Kind code	B2
Filing date	Sep 8, 2014
Priority date	Jun 25, 2003
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

Process for the preparation of electrodes from a porous material making it possible to obtain electrodes that are useful in electrochemical systems and that have at least one of the following properties: a high capacity in mAh/gram, a high capacity in mAh/liter, a good capacity for cycling, a low rate of self-discharge, and a good environmental tolerance.

First claim

The invention claimed is:

1. Porous silicon material obtained from a source of silicon, by electrochemical treatment, in a bath comprising at least one salt selected from the group consisting of NH X F Y , wherein x is 4 or 5 and y is 1 or 2, wherein the porous silicon material has an average pore size from about 10 nm to about 250 nm.

2. The porous silicon material of claim 1 , wherein the source of silicon is a silicon wafer or a silicon film.

3. The porous silicon material of claim 2 , wherein the silicon wafer or silicon film is obtained from a silicon monocrystal.

4. The porous silicon material of claim 1 , wherein the porous silicon material has a substantially uniform distribution of pores with a d50 between 100 and 150 nm.

5. The porous silicon material of claim 1 , wherein pores are located at the surface of the porous silicon material and extend throughout said porous silicon material, the pores have a depth between 1 μm and 3 mm, and said porous silicon material has a thickness between 2 μm and 3.5 mm.

6. The porous silicon material of claim 1 , wherein pores do not extend entirely throughout the porous silicon material.

7. The porous silicon material of claim 1 , wherein the porous silicon material is capable of forming an alloy with an alkali metal.

8. The porous silicon material of claim 1 , wherein the porous silicon material is obtained from a member of the group consisting of silicon wafers, silicon pellets, silicon films, silicon monocrystals and mixtures thereof.

9. The porous silicon material of claim 1 , wherein the bath contains at least one salt in a solution that is a mixture of H 2 SO 4 , NH 4 F and H 2 O, and of at least one non aqueous solvent that is selected from the group consisting of methanol, ethanol, acetone and mixtures thereof.

10. The porous silicon material of claim 1 , wherein the bath contains, in volume, from:
10 to 60% NH 4 F;
5 to 20% methanol; and
75 to 20% H 2 SO 4 .

11. The porous silicon material of claim 1 , wherein the NH X F Y is NH 4 F.

12. The porous silicon material of claim 1 , wherein the porous silicon material has a porosity of from about 5 volume % to about 95 volume %, as measured according to the porosimeter mercury method.

13. The porous silicon material of claim 12 , wherein the porosity of the porous silicon material is about 75 volume %.

14. The porous silicon material of claim 1 , wherein pores have an average depth of about 1 μm.

Assignees

• Hydro Quebec

Inventors

• Zaghib Karim
• Guerfi Abdelbast
• Charest Patrick
• Kostecki Robert
• Kinoshita Kimio
• Armand Michel

Classifications

• H01M4/1395

  of electrodes based on metals, Si or alloys · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/387

  Tin or alloys based on tin · CPC title

• H01M4/366

  as layered products · CPC title