Polyimide matrix electrolyte and improved batteries therefrom

• US 20040253520A1
• Filed: 05/13/2003
• Published: 12/16/2004
• Est. Priority Date: 05/13/2003
• Status: Abandoned Application

• Current Assignee: Craig R. Nelson, Robert W. Singleton, Scott Gustafson, Wensley C. Glen
• Original Assignee: Craig R. Nelson, Robert W. Singleton, Scott Gustafson, Wensley C. Glen
• Inventors: Wensley, C. Glen, Singleton, Robert W., Nelson, Craig R., Gustafson, Scott
• Application Number:
  US10/437,778
• Publication Number:
  US 20040253520A1
• Time in Patent Office: Days
• US Class Current: 429/306
• CPC Class Codes: H01M 10/0418 with bipolar electrodes
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0565 Polymeric materials, e.g. gel-type or solid-type
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 2300/0091 in the form of mixtures
• 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 4/621 Binders
• CPC Class Codes: H01M 4/622 being polymers
• CPC Class Codes: H01M 50/414 Synthetic resins, e.g. thermoplastics or thermosetting resins
• CPC Class Codes: H01M 50/446 Composite material consisting of a mixture of organic and inorganic materials
• CPC Class Codes: H01M 6/166 by the solute
• CPC Class Codes: H01M 6/181 with polymeric electrolytes
• CPC Class Codes: H01M 6/48 with bipolar electrodes
• 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

A battery includes an anode, a cathode, and a polymer matrix electrolyte (PME) separator disposed between the anode and the cathode. The PME separator includes a polyimide, at least one lithium salt in a concentration of at least 0.5 moles of lithium per mole of imide ring provided by the polyimide, and at least one solvent intermixed. The PME is generally homogeneous as evidenced by its high level of optically clarity. The battery can be a lithium ion or lithium metal battery.

Claims

1. A battery comprising:

an anode;

a cathode, and

at least one polymer matrix electrolyte (PME) separator disposed between said anode and said cathode, said PME separator comprising a polyimide, at least one lithium salt in a concentration of at least 0.5 moles of lithium per mole of imide ring provided by said polyimide, and at least one solvent intermixed, said PME being substantially optically clear.

2. The battery of claim 1, wherein said anode comprises lithium ion intercalation material.

3. The battery of claim 1, wherein said anode comprises lithium metal.

4. The battery of claim 1, wherein said anode comprises a lithium metal alloy anode.

5. The battery of claim 1, wherein a repeat unit weight per imide ring of said polyimide is no more than 350.

6. The battery of claim 1, wherein a repeat unit weight per imide ring of said polyimide is no more than 300.

7. The battery of claim 1, wherein a repeat unit weight per imide ring of said polyimide is no more than 250.

8. The battery of claim 1, wherein said polyimide is soluble at 25°

C. in at least one solvent selected from the group consisting of N-methylpyrrolidinone (NMP), dimethylacetamide (DMAc) and dimethylformamide (DMF).

9. The battery of claim 1, wherein the ionic conductivity of said polymer electrolyte at 25°

C. is at least 1×

10 4 S/cm.

10. The battery of claim 1, wherein the ionic conductivity of said polymer electrolyte at 25°

C. is at least 3×

10<sup>−

4</sup> S/cm.

11. The battery of claim 1, wherein said Li salt is at least one selected from the group consisting of LiCl, LiBr, Lil, LiClO₄, LiBF₄, LiAsF₆, LiPF₆, LiCF₃SO₃, LiBOB, LiN(CF₃SO₂)₂, and lithium bis(trifluorosulfonyl)imide (LiTFSI).

12. The battery of claim 1, wherein said cathode comprises an ion conducting polymeric binder intermixed with an intercalation material.

13. The battery of claim 12, wherein said polymeric binder comprises at least one polyimide.

14. The battery of claim 1, wherein said cathode further comprises an electrochemically active material selected from the group consisting of LiFePO₄, Li_xNi_yCO_zO₂, LiV_xO_y, Li_xMn_yO_z, LiV_xO_y, Li_xMn_yO_z, LiCoO₂, LiNiO₂ and LiTiS₂.

15. The battery of claim 1, wherein said battery provides no significant change in OCV and capacity following heating at 125°

C. for at least 5 minutes while under a pressure of at least 200 psi.

16. The battery of claim 1, wherein said battery provides no significant change in OCV and capacity following heating at 140°

C. for at least 10 minutes while under a pressure of at least 250 psi.

17. The battery of claim 1, wherein said battery is a bicell, wherein said cathode is folded over to sandwich said anode.

18. The battery of claim 1, wherein said salt and said polyimide do not provide any absorption peaks between 1630 and 1690 cm⁻

1, said PME providing at least one absorption between about 1630 and 1690 cm<sup>−

1</sup>.

19. The battery of claim 1, further comprising a package comprising packaging material surrounding said battery to form a packaged battery, said packaging material laminated to all exterior surfaces of said battery.

20. The battery of claim 1, further comprising a package comprising packaging material surrounding said battery and a frame having an opening to accommodate said battery therein to form a packaged battery, wherein said battery is disposed within said opening.

21. The battery of claim 20, wherein said packaged battery provides a thickness uniformity throughout within ±

1 mil.

22. A method for forming a battery, comprising the steps of:

providing a cathode layer disposed on a cathode current collector;

overcoating a mixture of polyimide, lithium salt and solvent on said cathode layer;

drying said mixture to remove at least a portion of said solvent, wherein an electrolyte separator bonded to said cathode (electrolyte/cathode) is formed, and

disposing an anode layer on said electrolyte/cathode.

23. The method of claim 22, wherein said electrolyte separator is a polymer matrix electrolyte (PME), wherein said lithium salt is in a concentration of at least 0.5 moles of lithium per mole of imide ring provided by said polyimide, said polyimide, said lithium salt and said solvent being intermixed, said PME being substantially optically clear.

24. The method of claim 22, wherein said anode is a lithium metal comprising anode.

25. The method of claim 23, wherein said battery is formed by laminating only two layers, a first layer being said PME disposed on said cathode and a second layer being said anode.

26. The method of claim 25, further comprising the step of folding said PME disposed on said cathode over said anode, wherein a bicell is formed.