ELECTROSPINNING FOR INTEGRATED SEPARATOR FOR LITHIUM-ION BATTERIES

• US 20120082884A1
• Filed: 09/02/2011
• Published: 04/05/2012
• Est. Priority Date: 09/30/2010
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Brown, Karl M., Yang, Lu, Bolandi, Hooman, Pebenito, Victor, Wang, Connie P., Bachrach, Robert Z., ORILALL, MAHENDRA C., Talwar, Raman
• Granted Patent: US 9,065,122 B2
• Time in Patent Office: Days
• US Class Current: 429/145
• CPC Class Codes: B05B 5/0255 spraying and depositing by electrostatic forces only
• CPC Class Codes: D01D 5/0084 Coating by electro-spinning, i.e. the electro-spun fibres are not removed from the collecting device but remain integral with it, e.g. coating of prostheses
• 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 2220/10 Batteries in stationary systems, e.g. emergency power source in plant
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 2220/30 Batteries in portable systems, e.g. mobile phone, laptop
• 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 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• 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 4/5815 Sulfides
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: H01M 50/403 Manufacturing processes of separators, membranes or diaphragms
• CPC Class Codes: H01M 50/42 Acrylic resins
• CPC Class Codes: H01M 50/423 Polyamide resins
• CPC Class Codes: H01M 50/434 Ceramics
• CPC Class Codes: H01M 50/44 Fibrous material
• CPC Class Codes: H01M 50/451 comprising layers of only organic material and layers containing inorganic material
• CPC Class Codes: H01M 50/491 Porosity
• 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

Abstract

Embodiments of the present invention relate generally to lithium-ion batteries, and more specifically, to batteries having integrated separators and methods of fabricating such batteries. In one embodiment, a lithium-ion battery having an electrode structure is provided. The lithium-ion battery comprises an anode stack, a cathode stack, and a porous electrospun polymer separator comprising a nano-fiber backbone structure. The anode stack comprises an anodic current collector and an anode structure formed over a first surface of the anodic current collector. The cathode stack comprises a cathodic current collector and a cathode structure formed over a first surface of the cathodic current collector. The porous electrospun polymer separator is positioned between the anode structure and the cathode structure.

Claims

1. A lithium-ion battery having an electrode structure, comprising:

an anode stack, comprising;

an anodic current collector; and

an anode structure formed over a first surface of the anodic current collector;

a cathode stack, comprising;

a cathodic current collector; and

a cathode structure formed over a first surface of the cathodic current collector; and

a porous electrospun polymer separator comprising a nano-fiber backbone structure positioned between the anode structure and the cathode structure.

2. The lithium-ion battery of claim 1, wherein the nano-fiber backbone structure further comprises ceramic particles embedded in nano-fibers of the nano-fiber backbone structure.

3. The lithium-ion battery of claim 2, wherein the ceramic particles are selected from the group of:

Pb(Zr,Ti)O₃ (PZT), PB(Mg₃Nb_2/3)O₃—

PbTiO₃ (PMN-PT), BaTiO₃, HfO₂ (hafnia), SrTiO₃, TiO₂ (titania), SiO₂ (silica), Al₂O₃ (alumina), ZrO₂ (zirconia), SnO₂, CeO₂, MgO, CaO, Y₂O₃ and combinations thereof.

4. The lithium-ion battery of claim 3, wherein the nano-fiber backbone structure comprises a first polymer material selected from polyamides, poly(acrylic acid) (PAA), polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), and styrene-butadiene (SBR).

5. The lithium-ion battery of claim 4, wherein the porous electrospun polymer separator further comprises a second polymer material deposited over the nano-fiber fiber backbone structure wherein the second polymer material is different from the first polymer material.

6. The lithium-ion battery of claim 4, wherein the second polymer material is selected from polyamides, poly(acrylic acid) (PAA), polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), and styrene-butadiene (SBR).

7. The lithium-ion battery of claim 1, wherein the cathode structure is a porous structure comprising a cathodically active material selected from the group comprising:

lithium cobalt dioxide (LiCoO₂), lithium manganese dioxide (LiMnO₂), titanium disulfide (TiS₂), LiNixCo_1-2xMnO₂, LiMn₂O₄, LiFePO₄, LiFe_1-xMgPO₄, LiMoPO₄, LiCoPO₄, Li₃V₂(PO₄)₃, LiVOPO₄, LiMP₂O₇, LiFe_1.5P₂O₇, LiVPO₄F, LiAlPO₄F, Li₅V(PO₄)₂F₂, Li₅Cr(PO₄)₂F₂, Li₂CoPO₄F, Li₂NiPO₄F, Na₅V₂(PO₄)₂F₃, Li₂FeSiO₄, Li₂MnSiO₄, Li₂VOSiO₄, LiNiO₂, and combinations thereof.

8. The lithium-ion battery of claim 3, wherein the nano-fibers of the nano-fiber backbone structure have a diameter between about 100 nanometers and about 200 nanometers.

9. The lithium-ion battery of claim 3, wherein the nano-fiber backbone structure has a porosity between about 40% to about 90% as compared to a solid film formed from the same material.

10. The lithium-ion battery of claim 5, wherein the first polymer material has a melting temperature greater than 200°

C. and the second polymer material has a melting temperature less than 140°

C. such that during thermal runaway, the second polymer material is melted and fused together, reducing porosity in the layer and thus slowing Li-ion transport and the associated electrochemical reactions.

11. A method of forming an electrode structure comprising:

providing a first electrode structure; and

electrospinning a nano-fiber backbone structure directly onto a surface of the first electrode structure to form a porous electrospun polymer separator.

12. The method of claim 11, wherein the nano-fiber backbone structure comprises a first polymer material selected from poly(acrylic acid) (PAA), polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), and styrene-butadiene (SBR).

13. The method of claim 12, wherein the electrospinning the nano-fiber backbone structure further comprises electrospinning a second polymer material different from the first polymer material which is selected from poly(acrylic acid) (PAA), polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), and styrene-butadiene (SBR).

14. The method of claim 12, further comprising electrospraying a second polymer material over the nano-fiber backbone structure wherein the second polymer is selected from polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), and styrene-butadiene (SBR).

15. The method of claim 12, wherein the nano-fiber backbone structure further comprises ceramic particles embedded in nano-fibers of the nano-fiber backbone structure.

16. The method of claim 15, wherein the ceramic particles are selected from the group of:

Pb(Zr,Ti)O₃ (PZT), Pb_1-xLa_xZr_1-yTi_yO₃ (PLZT, x and y are independently between 0 and

     1), PB(Mg₃Nb_2/3)O₃—

PbTiO₃ (PMN-PT), BaTiO₃, HfO₂ (hafnia), SrTiO₃, TiO₂ (titania), SiO₂ (silica), Al₂O₃ (alumina), ZrO₂ (zirconia), SnO₂, CeO₂, MgO, CaO, Y₂O₃ and combinations thereof.

17. The method of claim 15, wherein the electrospinning a nano-fiber backbone structure comprises:

depositing a polymer containing liquid mixture onto a surface parallel to a surface parallel to a surface of the first electrode structure, wherein the polymer containing liquid mixture comprises the ceramic particles; and

applying a voltage to the polymer containing liquid mixture to electrospin the nano-fiber backbone structure embedded with the ceramic particles onto the surface of the first electrode structure.

18. The method of claim 12, wherein the electrospinning a nano-fiber backbone structure directly onto a surface of the first electrode structure comprises:

electrospinning a first polymer material having a high melting temperature (T_m) greater than 200°

C.; and

electrospinning a second polymer material having a low melting temperature less than 140°

C. such that during thermal runaway, the low melting temperature polymer lines are melted and fused together, reducing porosity in the layer and thus slowing lithium-ion transport and the associated electrochemical reactions.

19. An in-line substrate processing system for forming an integrated separator over a flexible conductive substrate, comprising:

a microstructure formation chamber for forming at least a portion of an electrode structure over the flexible conductive substrate;

an electrospinning chamber for forming at least a portion of a porous electrospun polymer separator directly on the electrode structure; and

a substrate transfer mechanism configured to transfer the flexible conductive substrate among the chambers, comprising;

a feed roll disposed out side a processing volume of each chamber and configured to retain a portion of the flexible conductive substrate within the processing volume of each chamber; and

a take up roll disposed out side the processing volume and configured to retain a portion of the flexible conductive substrate, wherein the substrate transfer mechanism is configured to activate the feed rolls and the take up rolls to move the flexible conductive substrate in and out each chamber, and hold the flexible conductive substrate in the processing volume of each chamber.

20. The in-line substrate processing system of claim 19, further comprising:

an electrospraying chamber for forming at least a portion of the porous electrospun polymer separator over the flexible conductive substrate.