Method for the Preparation of Gamma-Liv205

• US 20080076025A1
• Filed: 10/18/2005
• Published: 03/27/2008
• Est. Priority Date: 10/22/2004
• Status: Active Grant

• Current Assignee: Blue Solutions (Bollore SA)
• Original Assignee: BatScap, Centre National De La Recherche Scientifique
• Inventors: Gaubicher, Joel, Dubarry, Matthieu, Morel, Benoit, Deschamps, Marc, Guyomard, Dominique
• Granted Patent: US 7,842,273 B2
• Time in Patent Office: Days
• US Class Current: 429/188
• CPC Class Codes: C01G 31/00 Compounds of vanadium
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2006/40 Electric properties
• 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 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/136 Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• CPC Class Codes: H01M 4/405 Alloys based on lithium
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/58 of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
• CPC Class Codes: H01M 4/5815 Sulfides
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The invention relates to the preparation of an optionally carbonaceous γ-LiV₂O₅ material.

The process consists in preparing a composition formed of carbon and of precursors of Li and of V and in subjecting it to a heat treatment. The composition is prepared by bringing carbon, α-V₂O₅ and a Li precursor into contact in amounts such that the ratio of the [V₂O₅]/[Li] concentrations is between 0.95 and 1.05 and the carbon is in excess of at least 25% with respect to the stoichiometry. The heat treatment is carried out in two stages: a first stage at a temperature between 90° C. and 150° C. for a time of 1 to 12 hours and a second stage at a temperature between 420° C. and 500° C. for a time of between 10 min and 1 hour, under a nitrogen or argon atmosphere or under vacuum. Applications: positive electrode active material.

Claims

1. A process for the preparation of a material composed of pure γ

-LiV₂O₅ or of γ

-LiV₂O₅ as an intimate mixture with carbon comprising preparing a composition formed of carbon and of precursors of Li and of V and subjecting said composition to a heat treatment, wherein;

the composition is prepared by bringing carbon, α

-V₂O₅ and a Li precursor into contact in amounts such that the ratio of the [V₂O₅]/[Li] concentrations is between 0.95 and 1.05 and the carbon is in excess of at least 25% with respect to the stoichiometry; and

the heat treatment is carried out in two stages;

a first stage at a temperature of between 90°

C. and 150°

C. for a time of 1 to 12 hours and a second stage at a temperature of between 420°

C. and 500°

C. for a time of between 10 min and 1 hour, under a nitrogen or argon atmosphere or under vacuum.

2. The process as claimed in claim 1, wherein the first stage is carried out with vigorous stirring.

3. The process as claimed in claim 1, wherein the Li precursor is LiOH.H₂O or Li₂CO₃, and the vanadium precursor α

-V₂O₅, the lithium precursor and the carbon are introduced into an amount of water such that a viscous suspension is obtained and vigorous stirring is maintained for a time of 1 to 2 hours.

4. The process as claimed in claim 3, wherein the concentrations of precursors vary between 0.5 mol/l and 5 mol/l for α

-V₂O₅, between 0.25 mol/l and 2.5 mol/l for the lithium precursor Li₂CO₃ and between 0.5 mol/l and 5 mol/l for the lithium precursor LiOH.H₂O.

5. The process as claimed in claim 1, wherein an aqueous solution comprising from 10 to 50% by volume of hydrogen peroxide is added to the reaction medium, vigorous stirring is maintained for 5 minutes and the limiting concentrations which can be used are from 0.05 mol/l to 2 mol/l for α

-V₂O₅ and from 0.025 mol/l to 2 mol/l for the Li precursor.

6. The process as claimed in claim 5, wherein the lithium precursor is Li₂CO₃, LiOH.H₂O, LiCl, LiNO₃ or a lithium salt of a carboxylic acid.

7. The process as claimed in claim 6, wherein the lithium salt is lithium acetylacetonate, lithium acetate, lithium stearate, lithium formate, lithium oxalate, lithium citrate, lithium lactate, lithium tartrate or lithium pyruvate.

8. The process as claimed in claim 5, wherein an aqueous suspension of α

-V₂O₅ and of carbon is prepared and an aqueous peroxide solution is added thereto, the lithium precursor being introduced into the aqueous suspension of α

-V₂O₅ and of carbon before the addition of the peroxide solution or after the addition of the peroxide solution, during the formation of the gel, and the mixture is left under vigorous stirring for 5 min.

9. The process as claimed in claim 5, wherein the respective amounts of Li precursor and of α

-V₂O₅ in the reaction medium are such that 0.1/z mol.l<sup>−

1</sup><

[Li]<

1 1/z mol.l<sup>−

1</sup>;

0.1 mol.l<sup>−

1</sup><

[V₂O₅]<

1 mol.l<sup>−

1</sup>, z being the number of lithium atoms per formula unit of the precursor.

10. A material composed of pure γ

-LiV₂O₅ or of γ

-LiV₂O₅ as an intimate mixture with carbon prepared by a process comprising preparing a composition formed of carbon and of precursors of Li and of V and subjecting said composition to a heat treatment, wherein;

the composition is prepared by bringing carbon, α

-V₂O₅ and a Li precursor into contact in amounts such that the ratio of the [V₂O₅]/[Li] concentrations is between 0.95 and 1.05 and the carbon is in excess of at least 25% with respect to the stoichiometry; and

the heat treatment is carried out in two stages;

a first stage at a temperature of between 90°

C. and 150°

C. for a time of 1 to 12 hours and a second stage at a temperature of between 420°

C. and 500°

C. for a time of between 10 min and 1 hour, under a nitrogen or argon atmosphere or under vacuum.

11. A composite positive electrode for a lithium battery, comprising a composite material which comprises the material composed of pure γ

-LiV₂O₅ or of γ

-LiV₂O₅ as an intimate mixture with carbon as claimed in claim 10.

12. The composite positive electrode as claimed in claim 11, wherein the composite material additionally comprises:

a binder conferring mechanical strength,

a compound conferring electron conduction, and

optionally a compound conferring ionic conduction.

13. The composite positive electrode as claimed in claim 12, wherein:

the content of the material composed of pure γ

-LiV₂O₅ or of γ

-LiV₂O₅ as an intimate mixture with carbon is between 90 and 100% by weight;

the content of binder is less than 10% by weight;

the content of compound conferring electron conduction is less than or equal to 5% by weight; and

the content of compound conferring ionic conduction is less than 5% by weight.

14. The electrode as claimed in claim 12, wherein the binder comprises a solvating polymer.

15. The electrode as claimed in claim 12, wherein the binder is a mixture of solvating polymer and of nonsolvating polymer.

16. The electrode as claimed in claim 12, wherein the binder additionally comprises a polar aprotic compound.

17. The electrode as claimed in claim 12, the compound conferring ionic conduction is a lithium salt selected from the group consisting of LiClO₄, LiPF₆, LiAsF₆, LiBF₄, LiR_FSO₃, LiCH₃SO₃, lithium bisperfluoroalkylsulfonimides and lithium bis- and trisperfluorosulfonylmethides.

18. A battery comprising of a negative electrode and a positive electrode separated by an electrolyte comprising a lithium salt in solution in a solvent, wherein the positive electrode is an electrode as claimed in claim 11.