Compositions and methods for improving the cumulative capacity of solid, secondary electrolytic cells

• US 5,541,020 A
• Filed: 02/04/1994
• Issued: 07/30/1996
• Est. Priority Date: 07/22/1993
• Status: Expired due to Fees

• Current Assignee: Valence Technology Incorporated (Lithium Werks B.V.)
• Original Assignee: Valence Technology Incorporated (Lithium Werks B.V.)
• Inventors: Pradhan, Bhuwon, Moulton, Russell D., Shackle, Dale R., Golovin, Milton N.
• Primary Examiner(s): KALAFUT, STEPHEN J
• Application Number:
  US08/193,047
• Time in Patent Office: 907 Days
• Field of Search: 429/192, 429/197, 429/212
• US Class Current: 429/317
• 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 10/0569 characterised by the solvents
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

This invention is directed to solid electrolytes containing a solvent and, in particular, a solvent comprising a mixture of an organic carbonate and triglyme as well as electrolytic cells prepared from such solid electrolytes. The electrolyte also contains an inorganic ion salt, preferably an alkali metal salt, and most preferably LiPF₆.

Claims

1. A solid, single-phase, solvent-containing electrolyte which comprises:

a solid polymeric matrix;

LiPF₆ ; and

a solvent comprising about a 10;

1 to 1;

2 weight ratio of an organic carbonate and a triglyme represented by Formula I;

space="preserve" listing-type="equation">RO(R.sub.1 O).sub.3 R.sub.2 I

where R and R₂ are independently selected from the group consisting of alkyl of from 1 to 6 carbon atoms, phenyl, alkphenyl of from 7 to 12 carbon atoms, and phenyl substituted with 1 to 3 substituents selected from the group consisting of alkyl of from 1 to 4 carbon atoms, alkoxy of from 1 to 4 carbon atoms, chloro and bromo;

R₁ is --(CR₃ R₄ CR₅ R₆)-- where R₃, R₄, R₅ and R₆ are independently selected from the group consisting of hydrogen and alkyl of from 1 to 4 carbon atoms; and

where the solid electrolyte does not include a separator.

2. The solid, single-phase, solvent-containing electrolyte of claim 1 wherein the R and R₂ are --CH₃ and R₁ is --(CH₂ CH₂)--.

3. The solid, single-phase, solvent-containing electrolyte of claim 2 wherein the organic carbonate is an alicyclic carbonate.

4. The solid, single-phase, solvent-containing electrolyte of claim 3 wherein the alicyclic carbonate is represented by the formula:

##STR9## where R₇, R₈, R₉, R₁₀, R₁₁, and R₁₂ are independently selected from the group consisting of hydrogen and alkyl of from 1 to 2 carbon atoms, and m is an integer equal to 0 or 1.

5. The solid, single-phase, solvent-containing electrolyte of claim 4 wherein m is zero, R₇, R₈, and R₁₁ are hydrogen and R₁₂ is selected from the group consisting of hydrogen, methyl, and --CH₂ CH₃.

6. The solid, single-phase, solvent-containing electrolyte of claim 5 wherein R₁₂ is --CH₂ CH₃.

7. The solid, single-phase, solvent-containing electrolyte of claim 5 wherein R₁₂ is methyl.

8. A solid, single-phase, solvent-containing eletrolyte of claim 1 wherein said LiPF₆ comprises from about 5 to about 25 weight percent based on the total electrolyte.

9. The solid, single-phase, solvent-containing electrolyte of claim 1 wherein the weight ratio of organic carbonate to the triglyme of Formula I is from about 9:

1 to about 1;

1.

10. The solid, single-phase, solvent-containing electrolyte of claim 9 wherein the weight ratio of organic carbonate to the triglyme of Formula I is about 4:

1 to about 2;

1.

11. The solid, single-phase, solvent-containing electrolyte of claim 9 wherein the weight ratio of organic carbonate to the triglyme of Formula I is about 4:

1 to about 1;

1.

12. A solid, secondary electrolytic cell which comprises:

an anode containing a compatible anodic material;

a cathode containing a compatible cathodic material; and

interposed therebetween a solid, solvent-containing electrolyte which comprises;

a solid polymeric matrix;

LiPF₆ ; and

a solvent comprising about a 10;

1 to 1;

2 weight ratio of an organic carbonate and a triglyme represented by Formula I;

space="preserve" listing-type="equation">RO(R.sub.1 O).sub.3 R.sub.2 I

where R and R₂ are independently selected from the group consisting of alkyl of from 1 to 6 carbon atoms, phenyl, alkphenyl of from 7 to 12 carbon atoms, and phenyl substituted with 1 to 3 substituents selected from the group consisting of alkyl of from 1 to 4 carbon atoms, alkoxy of from 1 to 4 carbon atoms, chloro and bromo;

R₁ is --(CR₃ R₄ CR₅ R₆)-- where R₃, R₄, R₅ and R₆ are independently selected from the group consisting of hydrogen and alkyl of from 1 to 4 carbon atoms; and

where the solid electrolyte does not include a separator.

13. The solid, secondary electrolytic cell of claim 12 wherein the R and R₂ are --CH₃ and R₁ is --(CH₂ CH₂)--.

14. The solid, secondary electrolytic cell of claim 12 wherein the organic carbonate is an alicyclic carbonate.

15. The solid, secondary electrolytic cell of claim 14 wherein the alicyclic carbonate is represented by the formula:

##STR10## where R₇, R₈, R₉, R₁₀, R₁₁, and R₁₂ are independently selected from the group consisting of hydrogen and alkyl of from 1 to 2 carbon atoms, and m is an integer equal to 0 or 1.

16. The solid secondary electrolytic cell of claim 15 wherein m is zero, R₇, R₈, and R₁₁ are hydrogen and R₁₂ is selected from the group consisting of hydrogen, methyl, and --CH₂ CH₃.

17. The solid, secondary electrolytic cell of claim 16 wherein R₁₂ is methyl.

18. The solid, secondary electrolytic cell of claim 16 wherein R₁₂ is --CH₂ CH₃.

19. The solid, secondary electrolytic cell of claim 12 wherein the weight ratio of organic carbonate to the triglyme of Formula I is from about 9:

1 to about 1;

1.

20. The solid, secondary electrolytic cell of claim 19 wherein the weight ratio of organic carbonate to the triglyme of Formula I is about 4:

1 to about 2;

1.

21. The solid, secondary electrolytic cell of claim 19 wherein the weight ratio of organic carbonate to the triglyme of Formula I is about 4:

1 to about 1;

1.

22. The solid, secondary electrolytic cell of claim 12 wherein said electrolyte further comprises a polyoxyalkylene film forming agent comprising repeating units of ##STR11## where R is hydrogen or alkyl of from 1 to 3 carbon atoms and x is an integer such that the number average molecular weight of the film forming agent is at least about 100,000.

23. The solid, secondary electrolytic cell of claim 22 wherein said electrolyte is prepared by a method comprises the steps of:

(a) combining the solvent and a prepolymer employed to prepare the solid polymeric matrix and mixing until homogeneous;

(b) adding the polyalkylene oxide film forming agent to the composition prepared in step (a) above and mixing until a substantially uniform dispersion is formed;

(c) heating the composition at a temperature above 55°

C. until the polyalkylene oxide is dissolved;

(d) cooling the composition prepared in step (c) to a temperature above the precipitation point for the polyalkylene oxide film forming agent and less than about 55°

C.;

(e) adding the inorganic ion salt to the composition prepared in step (d) while maintaining a temperature in the composition above the precipitation point for the polyalkylene oxide film forming agent and less than about 55°

C.; and

(f) applying a sufficient amount of the solution formed in step (e) onto a cathode and curing said solution so as to form a solid, solvent-containing electrolyte having a thickness of from about 25 to about 250 microns.

24. A solid, secondary electrolytic cell of claim 12 wherein said inorganic ion salt is an alkali metal salt.

25. A solid, secondary electrlytic cell of claim 12 wherein said LiPF₆ comprises from about 5 to about 25 weight percent based on the total electrolyte.

26. A battery comprising a plurality of the solid, secondary electrolytic cells of claim 12.

27. A solid, secondary electrolytic cell which comprises:

an anode containing a compatible anodic material;

a cathode containing a compatible cathodic material; and

interposed therebetween a solid, single-phase solvent-containing electrolyte which comprises;

a solid polymeric matrix;

LiPF₆ ; and

a solvent comprising about a 10;

1 to 1;

2 weight ratio of an aliphatic carbonate and a triglyme wherein the aliphatic carbonate is represented by the formulae;

space="preserve" listing-type="equation">R.sub.13 [OC(O)].sub.n OR.sub.14 and R.sub.13 [OC(O)R.sub.15 ].sub.p OC(O)R.sub.14

where each R₁₃ and R₁₄ are independently selected from the group consisting of alkyl of from 1 to 4 carbon atoms;

R₁₅ is an alkylene group of from 2 to 4 carbon atoms;

n is an integer of from 1 to 2, and p is an integer from 1 to 4 and the triglyme is represented by the Formula I

space="preserve" listing-type="equation">RO(R.sub.1 O).sub.3 R.sub.2 I

where R and R₂ are independently selected from the group consisting of alkyl of from 1 to 6 carbon atoms, phenyl, alkphenyl of from 7 to 12 carbon atoms, and phenyl substituted with 1 to 3 substituents selected from the group consisting of alkyl of from 1 to 4 carbon atoms, alkoxy of from 1 to 4 carbon atoms, chloro and bromo;

R₁ is --(CR₃ R₄ CR₅ R₆)-- where R₃, R₄, R₅ and R₆ are independently selected from the group consisting of hydrogen and alkyl of from 1 to 4 carbon atoms; and

where the solid electrolyte does not include a separator.

28. The solid single-phase, solvent-containing electrolyte of claim 27 wherein said LiPf₆ comprises from about 5 to about 25 weight percent based on the total electrolyte.

29. A solid, single-phase, solvent-containing electrolyte which comprises:

a solid polymeric matrix;

LiPF₆ ; and

a solvent comprising about a 10;

1 to 1;

2 weight ratio of an aliphatic carbonate and a triglyme wherein the aliphatic carbonate is represented by the formulae;

space="preserve" listing-type="equation">R.sub.13 [OC(O)].sub.n OR.sub.14 and R.sub.13 [OC(O)R.sub.15 ].sub.p OC(O)R.sub.14

where each R₁₃ and R₁₄ are independently selected from the group consisting of alkyl of from 1 to 4 carbon atoms;

R₁₅ is an alkylene group of from 2 to 4 carbon atoms;

n is an integer of from 1 to 2, and p is an integer from 1 to 4 and the triglyme is represented by the Formula I

space="preserve" listing-type="equation">RO(R.sub.1 O).sub.3 R.sub.2 I

where R and R₂ are independently selected from the group consisting of alkyl of from 1 to 6 carbon atoms, phenyl, alkphenyl of from 7 to 12 carbon atoms, and phenyl substituted with 1 to 3 substituents selected from the group consisting of alkyl of from 1 to 4 carbon atoms, alkoxy of from 1 to 4 carbon atoms, chloro and bromo;

R₁ is --(CR₃ R₄ CR₅ R₆)-- where R₃, R₄, R₅ and R₆ are independently selected from the group consisting of hydrogen and alkyl of from 1 to 4 carbon atoms; and

where the solid electrolyte does not include a separator.

30. A solid, single-phase, solvent-containing electrolyte of claim 29 wherein said LiPF₆ comprises from about 5 to about 25 weight percent based on the total electrolyte.

31. A method for enhancing the cumulative capacity of a solid, secondary electrolytic cell comprising an anode containing a compatible anodic material, a cathode containing a compatible cathodic material;

and interposed therebetween a solid, solvent-containing electrolyte which method comprises;

(a) selecting a solid, single-phase solvent-containing electrolyte which comprises;

a solid polymeric matrix;

LiPF₆ ; and

a solvent comprising about a 10;

1 to 1;

2 weight ratio of an organic carbonate and a triglyme represented by Formula I;

space="preserve" listing-type="equation">RO(R.sub.1 O).sub.3 R.sub.2 I

where R and R₂ are independently selected from the group consisting of alkyl of from 1 to 6 carbon atoms, phenyl, alkphenyl of from 7 to 12 carbon atoms, and phenyl substituted with 1 to 3 substituents selected from the group consisting of alkyl of from 1 to 4 carbon atoms, alkoxy of from 1 to 4 carbon atoms, chloro and bromo;

R₁ is --(CR₃ R₄ CR₅ R₆)-- where R₃, R₄, R₅ and R₆ are independently selected from the group consisting of hydrogen and alkyl of from 1 to 4 carbon atoms where the solid electrolyte does not include a separator; and

(b) incorporating the solid, single-phase solvent-containing electrolyte into the electrolytic cell.

32. The method of claim 31 wherein LiPF₆ comprises from about 5 to about 25 weight percent based on the total electrolyte.

33. The method of claim 31 wherein the R and R₂ are --CH₃ and R₁ is --(CH₂ CH₂)--.

34. The method of claim 33 wherein the organic carbonate is an alicyclic carbonate is represented by the formula:

##STR12## wherein R₇, R₈, R₉, R₁₀, R₁₁, and R₁₂ are independently selected from the group consisting of hydrogen and alkyl of from 1 to 2 carbon atoms; and

m is an integer equal to 0 or 1.

35. The method of claim 34 wherein m is zero, R₇, R₈, R₁₁, and R₁₂ are hydrogen.

36. The method of claim 33 wherein the organic carbonate is an aliphatic carbonate that is represented by the formulae:

space="preserve" listing-type="equation">R.sub.13 [OC(O)].sub.n OR.sub.14 and R.sub.13 [OC(O)R.sub.15 ].sub.p OC(O)R.sub.14

where each R₁₃ and R₁₄ are independently selected from the group consisting of alkyl of from 1 to 4 carbon atoms;

R₁₅ is an alkylene group of from 2 to 4 carbon atoms;

n is an integer of from 1 to 2, and p is an integer from 1 to 4.