Method for developing an electrochemical device

• US 20070169338A1
• Filed: 02/09/2005
• Published: 07/26/2007
• Est. Priority Date: 02/10/2004
• Status: Active Grant

• Current Assignee: Blue Solutions (Bollore SA)
• Original Assignee: BatScap
• Inventors: Deschamps, Marc
• Granted Patent: US 8,852,814 B2
• Time in Patent Office: Days
• US Class Current: 29/623.100
• CPC Class Codes: H01M 10/0436 Small-sized flat cells or batteries for portable equipment
• CPC Class Codes: H01M 10/052 Li-accumulators
• 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 10/0565 Polymeric materials, e.g. gel-type or solid-type
• CPC Class Codes: H01M 10/058 Construction or manufacture
• CPC Class Codes: H01M 2300/0085 Immobilising or gelification of electrolyte
• 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 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

The invention relates to the development of an electrochemical device including a lithium salt/polyether electrolyte film between two films forming the cathode and the anode, respectively. The method of the invention involves assembling a multilayer structure consisting of the current-collecting carrier, the cathode-forming film, the electrolyte-forming polyether film and the anode-forming film. The cathode and/or anode films are made of a composite material containing the lithium salt. The polyether film is lithium salt-free. The assembled device is allowed to rest for long enough to enable the lithium salt in the cathode and/or the anode to be dispersed throughout the polymer film.

Claims

1. A process for the preparation of an electrochemical device composed of a polyether/lithium salt electrolyte film between two films respectively constituting the positive electrode and the negative electrode, wherein the process comprises assembling a multilayer structure comprising a current-collecting support, a film intended to form the positive electrode, a polyether film intended to form the electrolyte and a film intended to form the negative electrode, wherein:

the film intended to form the positive electrode and/or the film intended to form the negative electrode are composed of a composite material comprising the lithium salt;

the polyether film intended to form the electrolyte does not comprise lithium salt;

the assembled device is left at rest for a time sufficient to allow the lithium salt present in the material of the positive electrode and/or in the material of the negative electrode to diffuse into the polymer film.

2. The process as claimed in claim 1, wherein the films respectively constituting the negative electrode, the positive electrode and the electrolyte have thicknesses of between 10 μ

m and 150 μ

m.

3. The process as claimed in claim 1, wherein the polyether is chosen from the copolymers which are obtained from ethylene oxide and from at least one substituted oxirane and which comprise at least 70% of —

CH₂—

CH₂O—

repeat units derived from ethylene oxide.

4. The process as claimed in claim 3, wherein the polyether comprises —

O—

CH₂—

CHR—

units, derived from an oxirane CH₂—

CHR—

O, in which R is an alkyl radical.

5. The process as claimed in claim 4, wherein R is an alkyl radical having from 1 to 16 carbon atoms.

6. The process as claimed in claim 3, wherein the polyether comprises —

O—

CH₂CHR′

—

units, derived from an oxirane CH₂—

CHR′

—

O in which R′

is a group capable of polymerizing by the radical route.

7. The process as claimed in claim 6, wherein said group capable of polymerizing by the radical route is selected from the group consisting of a vinyl, allyl, vinylbenzyl and acryloyl group.

8. The process as claimed in claim 3, wherein the polyether comprises repeat units derived from several substituted oxiranes.

9. The process as claimed in claim 1, wherein the composite material of the film intended to form the positive electrode comprises an active material, a binder, a material conferring electronic conductivity and the lithium salt.

10. The process as claimed in claim 9, wherein the positive electrode active material is selected from the group consisting of Li_1+xV₃O₈, 0<

x<

4, Li_xV₂O₅.nH₂O, 0<

x<

3, 0<

n<

2, LiFePO₄, hydrated or anhydrous iron phosphates and sulfates, hydrated or anhydrous vanadyl phosphates and sulfates, LiMn₂O₄, the compounds derived from LiMn₂O₄ obtained by partial substitution of Mn by Al, Ni and/or Co, LiMnO₂, the compounds derived from LiMnO₂ obtained by partial substitution of Mn by Al, Ni and/or Co, LiCoO₂, the compounds derived from LiCoO₂ obtained by partial substitution of Li by Al, Ti, Mg, Ni and/or Mn, LiNiO₂ and the compounds derived from LiNiO₂ obtained by partial substitution of Ni by Al, Ti, Mg and/or Mn.

11. The process as claimed in claim 1, wherein the film constituting the negative electrode is a lithium film.

12. The process as claimed in claim 1, wherein the film intended to form the negative electrode is composed of a composite material which comprises an active material, a binder, a material conferring electronic conductivity and the lithium salt.

13. The process as claimed in claim 12, wherein the active material is selected from the group consisting of:

carbon compounds,

alloys with lithium of Li_xM type (M=Sn, Sb, Si) (obtained from SnO, from SnO₂, from Sn, Sn—

Fe(—

C) compounds, from Si compounds, from Sb compounds), and

Li_xCu₆Sn₅ (0<

x<

13) compounds, iron borates, pnictides, simple oxides possessing reversible decomposition and insertion oxides, such as titanates, MoO₃ or WO₃.

14. The process as claimed in claim 1, wherein the lithium salt is selected from the group consisting of LiPF₆, LiAsF₆, LiClO₄, LiBF₄, LiC₄BO₈, Li(C₂F₅SO₂)₂N, Li[(C₂F₅)₃ PF₃], LiCF₃SO₃, LiCH₃SO₃ and LiN(SO₂CF₃)₂.

15. The process as claimed in claim 9, wherein the binder is composed either of a nonsolvating polymer and at least one polar aprotic compound, or of a solvating polymer.

16. The process as claimed in claim 15, wherein the polar aprotic compound is selected from the group consisting of linear or cyclic carbonates, linear or cyclic ethers, linear or cyclic esters, linear or cyclic sulfones, sulfamides and nitriles.

17. The process as claimed in claim 15, wherein the nonsolvating polymer is selected from the group consisting of:

vinylidene fluoride homopolymers and copolymers,

copolymers of ethylene, of propylene and of a diene,

tetrafluoroethylene homopolymers and copolymers,

N-vinylpyrrolidone homopolymers and copolymers,

acrylonitrile homopolymers and copolymers,

methacrylonitrile homopolymers and copolymers.

18. The process as claimed in claim 15, wherein the nonsolvating polymer carries ionic functional groups.

19. The process as claimed in claim 15, wherein the binder is a solvating polymer selected from the group consisting of polyethers of linear, comb or block structure, forming or not forming a network, based on poly(ethylene oxide);

copolymers comprising the ethylene oxide or propylene oxide or allyl glycidyl ether unit;

polyphosphazenes;

crosslinked networks based on polyethylene glycol crosslinked by isocyanates;

copolymers of oxyethylene and of epichlorohydrin; and

networks obtained by polycondensation which carry groups which make possible the incorporation of crosslinkable groups.

20. The process as claimed in claim 9, wherein the compound conferring electronic conduction properties is preferably a carbon black which does not catalyze the oxidation of the electrolyte at high potential.

21. The process as claimed in claim 9, wherein the composite material additionally comprises a nonvolatile liquid organic solvent.

22. The process as claimed in claim 21, wherein said liquid solvent is selected from the group consisting of:

polar aprotic compounds, such as linear or cyclic carbonates, linear or cyclic ethers, linear or cyclic esters, linear or cyclic sulfones, sulfamides and nitrites,

phthalates, such as dioctyl phthalate, dibutyl phthalate and dimethyl phthalate,

a polyethylene glycol or poly(ethylene glycol) dimethyl ether of low mass.

23. The process as claimed in claim 1, wherein the polyether of the film intended to form the electrolyte is a copolymer comprising crosslinkable units and in that at least one of the electrodes is composed of a composite material which additionally comprises a crosslinking agent for said polyether.