Nonaqueous liquid electrolyte

• US 20040197665A1
• Filed: 02/23/2004
• Published: 10/07/2004
• Est. Priority Date: 03/22/2002
• Status: Active Grant

• Current Assignee: Quallion, LLC (EnerSys), Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Quallion, LLC (EnerSys)
• Inventors: Vissers, Donald R, Tsukamoto, Hisashi, Wang, Qingzheng, Amine, Khalil, Oh, Bookeun, West, Robert C
• Granted Patent: US 7,695,860 B2
• Time in Patent Office: Days
• US Class Current: 429/313
• 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 2300/0082 Organic polymers
• CPC Class Codes: H01M 6/18 with solid electrolyte

Abstract

Disclosed is a nonaqueous liquid electrolyte comprising poly(siloxane-g-3 ethylene oxide) and its synthesis. This electrolyte provides significant safety, improved electrochemical stability, improved conductivity, lower impedance, and lower manufacturing costs.

Claims

1. A nonaqueous liquid type polymeric electrolyte comprising:

poly(siloxane-g-ethylene oxide) represented by the formula

wherein n=4 to 20, m=0 to 20, and R₄ is [—

O-(alkylene oxide)_k-R₁₁] wherein R₁₁ is alkyl group; and

at least one ionizable salt.

2. The nonaqueous liquid type polymeric electrolyte of claim 1 wherein n is equal to 4 to 12.

3. The nonaqueous liquid type polymeric electrolyte of claim 1 wherein n is approximately equal to 8.

4. The nonaqueous liquid type polymeric electrolyte of claim 1 wherein m is equal to 0 to 8.

5. The nonaqueous liquid type polymeric electrolyte of claim 1 wherein m is approximately equal to 0.

6. The nonaqueous, liquid type polymeric electrolyte of claim 1 wherein n=4 to 12 and m is approximately equal to 0.

7. The nonaqueous liquid type polymeric electrolyte of claim 1 wherein n is approximately equal to 8 and m is approximately equal to 0.

8. The nonaqueous liquid type polymeric electrolyte of claim 1 wherein R1, R2, R3, R8, R9 and R10 are chosen from the group consisting of:

methyl, ethyl, propyl, and butyl.

9. The nonaqueous liquid type polymeric electrolyte of claim 1 wherein R5, R6 and R7 are chosen from the group consisting of:

methyl, ethyl, propyl and butyl.

10. The nonaqueous liquid type polymeric electrolyte of claim 1 wherein said R4 is poly(ethylene oxide) ether.

11. The nonaqueous liquid type polymeric electrolyte of claim 10 wherein said poly(ethylene oxide) ether is methyl ether.

12. The nonaqueous liquid type polymeric electrolyte of claim 10 wherein k is equal to 2 to 10.

13. The nonaqueous liquid type polymeric electrolyte of claim 10 wherein k is approximately equal to 3.

14. The nonaqueous liquid type polymeric electrolyte recited in claim 1 wherein said dissolved ionizable salt is an alkali metal salt.

15. The nonaqueous liquid type polymeric electrolyte recited in claim 14 wherein said alkali metal salt comprises a lithium salt.

16. The nonaqueous liquid type polymeric electrolyte recited in claim 14 wherein said salt comprises at least one salt selected from the group consisting of:

LiN(SO₂CF₃)₂ (LiTFSI), LiClO₄, LiBF₄, LiAsF₆, LiPF₆, LiCF₃SO₃, Li(CF₃SO₂)₂N, LiC(CF₃SO₂)₃, LiN(SO₂C₂F₅)₂, lithium bis(chelato) borate having five to seven membered rings, and lithium alkyl fluorophosphates.

17. The nonaqueous liquid type polymeric electrolyte recited in claim 1 wherein the side chain oxygen vs. lithium ratio is 5:

1 to 50;

1.

18. The nonaqueous liquid type polymeric electrolyte recited in claim 1 wherein the side chain oxygen vs. lithium ratio is about 10:

1 to about 35;

1.

19. The nonaqueous liquid type polymeric electrolyte recited in claim 1 wherein the side chain oxygen vs. lithium ratio is 12:

1 to 28;

1.

20. The nonaqueous liquid type polymeric electrolyte recited in claim 1 wherein the side chain oxygen vs. lithium ratio is about 15:

1 to about 25;

1.

21. The nonaqueous liquid type polymeric electrolyte recited in claim 1 wherein the side chain oxygen vs. lithium ratio is about 15:

1.

22. The nonaqueous liquid type polymeric electrolyte of claim 1 wherein said ionizable salt comprises a quaternary ammonium salt having an anion selected form the following groups:

ClO₄⁻

, BF₄⁻

, AsF₆⁻

, PF₆⁻

, CF₃SO₃⁻

, (CF₃SO₂)₂N<sup>−

, (CF</sup>₃SO₂)₃C⁻

, (C₂F₅SO₂)₂N⁻

, PF₃(C₂F₅)₃⁻

, PF₃(CF₃)₃⁻

, and B(C₂O₄)₂⁻

.

23. The nonaqueous liquid type polymeric electrolyte recited in claim 1 further comprising boron detectable by at least one technique chosen from the following:

mass spectroscopy, nuclear magnetic resonance (NMR), X-ray, and Fourier Transform Infrared Spectroscopy (FTIR).

24. An electrochemical storage device comprising said electrolyte recited in claim 1.

25. A medical device powered by at least one electrochemical storage device recited in claim 24.

26. A method for synthesizing a polyhydrosiloxane intermediary for preparing poly(siloxane-g-ethylene oxide), represented by the formula:

27. The method recited in claim 26 wherein said precursor comprises a cyclic polysiloxane.

28. The method recited in claim 26 wherein said precursor comprises a cyclic polysiloxane with three to ten silicon-oxygen repeating units.

29. The method recited in claim 28 wherein said precursor comprises 1,3,5,7,9-pentamethylcyclopentasiloxane.

30. The method recited in claim 26 wherein said precursor comprises a cyclic polysiloxane with three to five silicon-oxygen repeating units.

31. The method recited in claim 26 wherein said precursor comprises 1,3,5-trimethylcyclotrisiloxane.

32. The method recited in claim 26 wherein said precursor comprises 1,3,5,7-tetramethylcyclotetrasiloxane.

33. The method recited in claim 26 wherein said chain-stopping compound comprises a disiloxane represented by the formula:

34. The method recited in claim 33 wherein R1, R2, R3, R8, R9, and R10 are chosen from the group consisting of:

hydrogen, methyl, ethyl, propyl, and butyl.

35. The method recited in claim 26 wherein said chain-stopping compound comprises hexamethyldisiloxane (HMDS).

36. The method recited in claim 26 wherein said ring opening polymerization comprises the act of adding a chain stopping compound in the presence of sulfuric acid.

37. The method recited in claim 26 wherein said ring opening polymerization comprises the act of adding hexamethyldisiloxane in the presence of sulfuric acid.

38. A method for synthesizing a polysiloxane electrolyte comprising the acts of:

providing a polyhydrosiloxane intermediary represented by the formula;

wherein n=4 to 20 and at least R4, R5, R6, or R7 comprises hydrogen;

mixing with a hydroxyl compound;

adding a dehydrocoupling catalyst;

flushing with inert gas;

adding a solvent;

heating the resulting mixture;

stirring;

drying in a vacuum; and

doping with at least one lithium salt.

39. The method recited in claim 38 wherein said m=0.

40. The method recited in claim 38 wherein said R groups that are not hydrogen are methyl groups.

41. The method recited in claim 38 wherein said polyhydrosiloxane intermediary comprises a structure represented by the formula:

42. The method recited in claim 38 wherein said dehydrocoupling catalyst contains boron.

43. The method recited in claim 38 wherein said dehydrocoupling catalyst comprises tris(pentafluorophenyl)boron (B(C₆F₅)₃).

44. The method recited in claim 38 wherein said dehydrocoupling catalyst is loaded as a percentage of the moles of Si—

H groups present in the substrates.

45. The catalyst loading of claim 44 wherein said loading percentage is 0.01% to 10.00% on a per mole basis.

46. The catalyst loading of claim 44 wherein said loading percentage is 0.01% to 2.00% on a per mole basis.

47. The catalyst loading of claim 44 wherein said loading percentage is approximately equal to 0.05% on a per mole basis.

48. The method recited in claim 38 wherein said hydroxyl compound comprises a substituted methyl alcohol.

49. The method recited in claim 38 wherein said hydroxyl compound comprises a poly(ethylene glycol) ether.

50. The method recited in claim 38 wherein said hydroxyl compound comprises a poly(ethylene glycol) monomethyl ether.

51. The method recited in claim 38 wherein said hydroxyl compound comprises tri(ethylene glycol) monomethyl ether.

52. The method recited in claim 38 wherein said polyhydrosiloxane contains 4 to 20 siloxane repeating units.

53. The method recited in claim 38 wherein said inert gas is chosen from the group consisting of:

argon, nitrogen, and mixtures thereof.

54. The method recited in claim 38 wherein said inert gas is anhydrous.

55. The method recited in claim 38 wherein said solvent is toluene.

56. The method recited in claim 38, wherein said solvent is benzene.

57. The method recited in claim 38 wherein said heating of said resulting mixture is to a range between 40 and 200°

C.

58. The method recited in claim 38 wherein said heating of said resulting mixture is to about 70 to 75°

C.

59. The method recited in claim 38 wherein said at least one lithium salt is selected from the group consisting of:

LiN(SO₂CF₃)₂ (LiTFSI), LiClO₄, LiBF₄, LiAsF₆, LiPF₆, LiCF₃SO₃, Li(CF₃SO₂)₂N, LiC(CF₃SO₂)₃, LiN(SO₂C₂F₅)₂, bis(chelato) borate having five to seven membered rings, lithium alkyl fluorophosphates, and mixtures thereof.

60. A method for synthesizing poly(siloxane-g-3 ethylene oxide) (n˜

8) comprising the acts of;

providing precursor 1,3,5,7-tetramethylcyclcotetrasiloxane (D₄^H);

providing a chain stopping compound hexamethyldisiloxane (HMDS);

performing a ring opening polymerization reaction;

adding HMDS (in a 1;

2 molar ratio) in the presence of concentrated sulfuric acid;

stirring;

bringing mixture to room temperature;

washing;

dissolving in solvent;

removing the solvent;

mixing with an ethyleneglycol monomethyl ether, and

adding a dehydrocoupling catalyst.

61. The method recited in claim 60 wherein said dehydrocoupling catalyst comprises tris(pentafluorophenyl)boron B(C₆F₅)₃.

62. The method recited in claim 60 further comprising the act of doping with at least one alkali metal salt.

63. The method recited in claim 62 wherein said alkali metal salt comprises a lithium salt.

64. The method recited in claim 63 wherein at least one lithium salt is selected from the group consisting of:

LiN(SO₂CF₃)₂ (LiTFSI), LiClO₄, LiBF₄, LiAsF₆, LiPF₆, LiCF₃SO₃, Li(CF₃SO₂)₂N, LiC(CF₃SO₂)₃, LiN(SO₂C₂F₅)₂, bis(chelato) borate having five to seven membered rings, lithium alkyl fluorophosphates, and mixtures thereof.

65. A nonaqueous electrolyte made by the process of claim 60.

66. An electrochemical storage device comprising said electrolyte recited in claim 65.

67. A medical device powered by at least one electrochemical storage device recited in claim 66.