Electrolyte for electrochemical cell

• US 7,473,491 B1
• Filed: 09/15/2003
• Issued: 01/06/2009
• Est. Priority Date: 09/15/2003
• Status: Active Grant

• Current Assignee: Quallion, LLC (EnerSys)
• Original Assignee: Quallion, LLC (EnerSys)
• Inventors: Zhang, Zhengcheng, West, Robert C., Amine, Khalil, Oh, Bookeun
• Primary Examiner(s): Tsang-Foster; Susy
• Assistant Examiner(s): ECHELMEYER, ALIX ELIZABETH
• Application Number:
  US10/663,024
• Time in Patent Office: 1,940 Days
• Field of Search: None
• US Class Current: 429/303
• CPC Class Codes: C08G 77/46 containing polyether sequences
• CPC Class Codes: H01B 1/122 Ionic conductors
• CPC Class Codes: H01G 11/56 Solid electrolytes, e.g. gels; Additives therein
• CPC Class Codes: H01G 11/62 characterised by the solute, e.g. salts, anions or cations therein
• 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 10/0566 Liquid materials
• CPC Class Codes: H01M 2300/0025 Organic electrolyte
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 2300/0094 in the form of layered products, e.g. coatings
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

The electrolyte includes a cyclic polysiloxane having one or more side chains that each includes a poly(alkylene oxide) moiety and a spacer. Each spacer is positioned between the poly(alkylene oxide) moiety and a silicon on the main chain of the polysiloxane.

Claims

1. An electrochemical device, comprising:

an electrolyte including a cyclic polysiloxane having side chains that each includes a poly(alkylene oxide) moiety and a spacer positioned between the poly(alkylene oxide) moiety and a silicon on a main chain of the polysiloxane,

the polysiloxane having a structure represented by the formula;

2. The device of claim 1, wherein the spacer includes 2 or more CH₂ groups.

3. The device of claim 1, wherein the spacer includes 6 or fewer CH₂ groups.

4. The device of claim 1, wherein the cyclic polysiloxane is cross-linked.

5. The device of claim 1, wherein the electrolyte is a liquid.

6. The device of claim 1, wherein the electrolyte includes at least one alkali metal salt.

7. The device of claim 6, wherein the alkali metal salt is selected from a group consisting of:

LiClO₄, LiBF₄, LiAsF₆, LiPF₆, LiCF₃SO₃, Li(CF₃SO₂)₂N, Li(CF₃SO₂)₃C, LiN(SO₂C₂F₅)₂), lithium alkyl fluorophosphates, lithium bis(chelato)borates, LiPF₃(C₂F₅)₃, and LiPF₃(CF₃)₃.

8. The device of claim 1, wherein the electrolyte includes a lithium bis(chelato)borate having 5 to 10 membered rings.

9. The device of claim 1, wherein the electrolyte includes a lithium bis(chelato)borate having 5 to 7 membered rings.

10. The device of claim 1, wherein the cyclic polysiloxane is entrapped within at least one cross-linked network polymer.

11. The device of claim 10, wherein the electrolyte is a solid.

12. The device of claim 10, wherein the at least one network polymer includes a poly(methacrylate).

13. The device of claim 10, wherein the network polymer is formed from a monomer represented by general formula:

14. The device of claim 10, wherein the network polymer includes a cross-linked polysiloxane.

15. The device of claim 10, wherein the network polymer includes a polysiloxane where at least a portion of the main chain silicons are linked to side chains that each include a poly(alkylene oxide) moiety.

16. The device of claim 15, wherein at least a portion of the main chain silicons are bonded to a cross-linker having a moiety selected from the group consisting of:

O—

(CH₂CH₂O)_q and Si—

O—

(Si—

O)_k—

Si, where q is at least 4 and less than 30, and k is at least 5 and less than 30.

17. The device of claim 15, wherein n of the main chain silicons are bonded to a cross-linker and m of the main chain silicons bonded to a side chain, a ratio of n:

m being in a range of 1;

4 to 1;

200.

18. The device of claim 17, wherein the ratio of n:

m is in a range of 1;

6 to 1;

100.

19. The device of claim 1, wherein the electrolyte further includes:

at least one solid polymer.

20. The device of claim 19, wherein the at least one solid polymer is selected from the group consisting of:

polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVdF), poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinyl acetate), polystyrene, and poly(ethylene oxide) (PEO).

21. The device of claim 1, wherein the average molecular weight of the cyclic polysiloxane is less than or equal to 20,000 g/mol.

22. The device of claim 1, wherein the dynamic viscosity of the cyclic polysiloxane is less than or equal to 10,000 cps.

23. The device of claim 1, wherein a [EO]/[Li] ratio is 5 to 50,

[EO] being a molar concentration in the electrolyte of active oxygens in the polysiloxane, and

[Li] being a molar concentration of the lithium in the electrolyte.

24. The device of claim 1, further comprising:

at least one lithium metal oxide cathode, at least one porous separator, and at least one anode.

25. The device of claim 24, wherein the at least one anode comprises at least one material selected from the group consisting of:

carbon and lithium metal.

26. The device of claim 1, wherein the electrolyte includes a blend of polysiloxanes.

27. The device of claim 1, wherein the spacer includes 3 or more CH₂ groups.

28. The device of claim 1, wherein R₁ is hydrogen.

29. The device of claim 1, wherein the electrolyte further includes a polysiloxane having a structure represented by the formula:

30. The device of claim 29, wherein the electrolyte is a solid.

31. The device of claim 29, wherein at least a portion of the cross-linkers include a moiety selected from the group consisting of O—

(CH₂CH₂O)_q and Si—

O(Si—

O)_k—

Si, where q is at least 4 and less than 30, and k is at least 5 and less than 30.

32. An electrochemical device, comprising:

an electrolyte including a cyclic polysiloxane having side chains that each includes a poly(alkylene oxide) moiety and a spacer positioned between the poly(alkylene oxide) moiety and a silicon on a main chain of the polysiloxane,

the polysiloxane having a structure represented by a formula that includes the variables R, R′

, R₁, R₂, n, and x;

the variable R representing an alkyl or aryl group;

the variable R′

representing an alkyl or aryl group;

the variable R₁ representing hydrogen or an alkyl group;

the variable R₂ representing the spacer and consisting of one or more CH₂ groups;

the variable n being 4 to 100;

the variable x being 1 to 30; and

the formula being