ELECTRODE-FORMING COMPOSITION

• US 20140342224A1
• Filed: 09/06/2012
• Published: 11/20/2014
• Est. Priority Date: 09/13/2011
• Status: Active Grant

• Current Assignee: Solvay Specialty Polymers Italy S.p.A. (Solvac SA)
• Original Assignee: Solvay Specialty Polymers Italy S.p.A. (Solvac SA)
• Inventors: Pieri, Riccardo, Apostolo, Marco, Cojocaru, Paula
• Granted Patent: US 10,333,146 B2
• Time in Patent Office: Days
• US Class Current: 429/217
• CPC Class Codes: H01G 11/22 Electrodes
• CPC Class Codes: H01G 11/58 Liquid electrolytes
• CPC Class Codes: H01G 9/0029 Processes of manufacture
• CPC Class Codes: H01M 4/0409 by a doctor blade method, slip-casting or roller coating
• CPC Class Codes: H01M 4/0414 by screen printing
• CPC Class Codes: H01M 4/0419 involving spraying
• CPC Class Codes: H01M 4/36 Selection of substances as active materials, active masses, active liquids
• CPC Class Codes: H01M 4/366 as layered products
• CPC Class Codes: H01M 4/38 of elements or alloys
• 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 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: H01M 4/621 Binders
• CPC Class Codes: H01M 4/623 fluorinated polymers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/49115 including coating or impregnating

Abstract

The invention pertains to an aqueous electrode-forming composition comprising:—at least one fluoropolymer [polymer (F)];—particles of at least one powdery active electrode material [particles (P)], said particles (P) comprising a core of an active electrode compound [compound (E)] and an outer layer of a metallic compound [compound (M)] different from Lithium, said outer layer at least partially surrounding said core; and—water, to a process for its manufacture, to a process for manufacturing an electrode structure using the same, to an electrode structure made from the same and to an electrochemical device comprising said electrode structure.

Claims

1. An aqueous electrode-forming composition comprising:

at least one polymer (F), wherein polymer (F) is a fluoropolymer;

particles of at least one powdery active electrode material (P), said particles (P) comprising a core of an active electrode compound (E) and an outer layer of a metallic compound (M) different from Lithium, said outer layer at least partially surrounding said core; and

water.

2. The aqueous electrode-forming composition of claim 1, wherein polymer (F) is a vinylidene fluoride (VDF) polymer comprising:

(a′

) at least 50% by moles of recurring units derived from vinylidene fluoride (VDF);

(b′

) optionally from 0.1 to 20% by moles of a fluorinated monomer different from VDF; and

(c′

) optionally from 0.1 to 10%, by moles, based on the total amount of monomers (a′

) and (b′

), of one or more hydrogenated monomer(s).

3. The aqueous electrode-forming composition of claim 2, wherein polymer (F) is a VDF polymer comprising recurring units derived from vinylidene fluoride (VDF) and from at least one (meth)acrylic monomer (MA) having formula (I):

4. The aqueous electrode-forming composition of claim 1, wherein compound (E) is selected from the group consisting of active cathode compounds (E+).

5. The aqueous electrode-forming composition of claim 4, wherein compound (E+) is selected from the group consisting of:

composite metal chalcogenides represented by a general formula of LiMY₂, wherein M denotes one or more than one transition metal, including Co, Ni, Fe, Mn, Cr and V; and

Y denotes a chalcogen, including O and S; and

lithiated or partially lithiated transition metal oxyanion-based electrode materials of the nominal formula AB(XO₄)_fE<sub>1−

f</sub>, in which A is lithium, which may be partially substituted by another alkali metal representing less that 20% of the A metals, B is a main redox transition metal at the oxidation level of +2 chosen from Fe, Mn, Ni or mixtures thereof, which may be partially substituted by one or more additional metal at oxidation levels between +1 and +5 and representing less than 35% of the main +2 redox metals, including 0, XO₄ is any oxyanion in which X is either P, S, V, Si, Nb, Mo or a combination thereof, E is a fluoride, hydroxide or chloride anion, f is the molar fraction of XO₄ oxyanion, which is comprised between 0.75 and 1.

6. The aqueous electrode-forming composition of claim 5, wherein compound (E+) is selected from the group consisting of LiCoO₂, LiNiO₂, LiMnO₂, LiNi_xCo₁₋

xO₂ (wherein 0<

x<

1), Li_xCo<sub>1−

y</sub>Al_yO₂ (wherein 0<

x<

1, and 0<

y<

1), LiMn₂O₄, LiFePO₄ and Li(Fe_xMn<sub>1−

x</sub>)PO₄ (wherein 0<

x<

1).

7. The aqueous electrode-forming composition of claim 1, wherein the compound (M) comprises at least one of Rh, Ir, Ru, Ti, Re, Os, Cd, Tl, Pb, Bi, In, Sb, Al, Ti, Cu, Ni, Pd, V, Fe, Cr, Mn, Co, Zn, Mo, W, Ag, Au, Pt, Ir, Ru, Pd, Sn, Ge, or Ga.

8. The aqueous electrode-forming composition of claim 7, wherein the compound (M) is Cu, Ag or an alloy of Ag and/or of Cu.

9. The aqueous electrode-forming composition of claim 1, said composition additionally comprising at least one electroconductivity-imparting additive.

10. The aqueous electrode-forming composition of claim 1 said composition being substantially free from additional liquid solvent different from water.

11. A process for manufacturing the electrode-forming composition of claim 1, said process comprising mixing polymer (F) and particles (P), and optionally other ingredients, in an aqueous medium.

12. The process of claim 11, wherein mixing of polymer (F), particles (P) and all optional ingredients is performed by an apparatus selected from a roll kneader, a mixer, a homo mixer, a ball mixer, a bead mill.

13. A process for manufacturing an electrode structure, said process comprising applying the electrode-forming composition of claim 1 onto at least one surface of a substrate.

14. The process of claim 13, wherein the electrode-forming composition is applied by a wet coating process, selected from screen printing, coating using a roll coater, a blade coater, a slit coater, a curtain coater, a wire coater, a sprayer, a foam applicator, and a brush coater.

15. An electrode structure made from the electrode-composition of claim 1.

16. An electrochemical device comprising an electrode structure according to claim 15.

17. The aqueous electrode-forming composition of claim 2, wherein polymer (F) is a vinylidene fluoride (VDF) polymer comprising:

(a′

) at least 80% by moles of recurring units derived from vinylidene fluoride (VDF);

(b′

) optionally from 0.1 to 10% by moles of a fluorinated monomer different from VDF; and

(c′

) optionally from 0.1 to 3% by moles, based on the total amount of monomers (a′

) and (b′

), of one or more hydrogenated monomer(s).

18. The aqueous electrode-forming composition of claim 17, wherein the fluorinated monomer different from VDF is selected from vinylfluoride (VF₁), chlorotrifluoroethylene (CTFE), hexafluoropropene (HFP), tetrafluoroethylene (TFE), perfluoromethylvinylether (MVE), trifluoroethylene (TrFE) and mixtures thereof.

19. The aqueous electrode-forming composition of claim 9, wherein the electroconductivity-imparting additive is at least one additive selected from carbon black, graphene or carbon nanotubes, and powders and fibers of metals, including nickel and aluminium.

20. An aqueous electrode-forming composition comprising:

at least one polymer (F), wherein polymer (F) is a is a vinylidene fluoride (VDF) polymer comprising;

(a′

) at least 80% by moles of recurring units derived from vinylidene fluoride (VDF), and

(c′

) from 0.1 to 3%, by moles of at least one (meth)acrylic monomer (MA) having formula (I);