Bis (perfluoralkanesulfonyl)imide surfactant salts in electrochemical systems

• US 6,280,883 B1
• Filed: 03/12/1999
• Issued: 08/28/2001
• Est. Priority Date: 12/10/1997
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Fanta, Alan D., Johnson, Bryan J., Lamanna, William M., Pham, Phat T., Shimada, Hiroshi, Boyd, Steven D., Loch, Robert B.
• Primary Examiner(s): WEINER, LAURA S
• Application Number:
  US09/267,310
• Time in Patent Office: 900 Days
• Field of Search: 429/309, 429/314, 429/315, 429/316, 429/231.1, 429/231.8, 429/199, 429/231.4, 429/307, 252/62.2
• US Class Current: 429/307
• CPC Class Codes: C07C 311/48 having nitrogen atoms of sulfonamide groups further bound to another hetero atom
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 50/417 Polyolefins
• CPC Class Codes: H01M 6/166 by the solute
• CPC Class Codes: H01M 6/168 by additives
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Electrolyte compositions and electrochemical systems containing such compositions are described where the electrolyte includes in a matrix material a combination of a conductive salt and a bis(perfluoroalkanesulfonyl)imide surfactant salt. The compositions improve wettability of electrodes and separators while maintaining and improving conductivity, stability, and compatibility with other cell components.

Claims

1. An electrolyte composition comprising:

(a) a conductive salt comprising

a cation selected from the group consisting of an alkali metal;

an alkaline earth metal;

a Group IIB metal;

a Group IIIB metal;

a transition metal;

a rare earth metal;

a nitrogen onium cation, and a proton; and

an anion selected from the group consisting of R_f⁰SO₃₋

;

in which R_f⁰ is a perfluoroalkyl group having between 2 and 4 carbon atoms;

an anion of the formula;

in which R_f1 and R_f2 are each independently a straight or branched perfluoroalkyl group of 1 to 4 carbon atoms, with R_f1 and R_f2 having a total of up to 5 carbon atoms;

and R_f3 is a perfluoroalkylene moiety of 2 to 4 carbon atoms optionally substituted by a straight or branched perfluoroalkyl group of 1 to 2 carbon atoms, with R_f3 having a total of up to 4 carbon atoms;

an anion having a formula R_f4R_f5N—

(CF₂)_n′

SO₂—

X;

in which X⁻

is —

O⁻

, —

N⁻

SO₂R_f4, or

Z is —

CF₂—

, —

O—

,

or —

SF₄—

;

R_f4, R_f4′

, and R_f5, independently, are —

C_mF_2m+1′

or —

(CF₂)_q—

SO₂—

X⁻

;

R_f6 and R_f7, independently, are —

C_mF_2m+1, —

(CF₂)₄—

SO₂—

X⁻

,

R_f8 is —

C_mF_2m+1, or —

(CF₂)_q—

SO₂—

X⁻

;

R_f6′

and R_f7′

, independently, are perfluoroalkylene moieties having the formula —

C_rF_2r—

;

n′

is 1-4;

r is 1-4;

m is 1-4; and

q is 1-4;

a bis-fluoroalkylsulfonyl methide anion R_f^II—

SO₂—

C⁻

(R)—

SO₂—

R_f^III in which R_f^II and R_f^III, independently, are perfluoroalkyl groups having between 1 and 4 carbon atoms, wherein the sum of R₄^II and R_f^III is up to 5 carbon atoms, and R is H, CN, F, alkyl of 1 to 6 carbon atoms, phenyl or phenyl substituted by alkyl of 1 to 4 carbon atoms;

and a tris-(perfluoroalkanesulfonyl)methide anion of the formula <sup>−

C(SO</sup>₂R_f^II)(SO₂R_f^III)(SO₂R_f^IV) in which R_f^II, R_f^III, and R_f^IV, independently, are perfluoroalkyl groups having between 1 and 4 carbon atoms, wherein the sum of R_f^II, R_f^III and R_f^IV are up to 6 carbon atoms; and

(b) a surfactant salt of the formula;

2. The composition of claim 1, wherein R_f is a straight or branched perfluoroalkyl group of 4 to 12 carbon atoms, and R_f′

is a straight or branched perfluoroalkyl group of 1 to 8 carbon atoms.

3. The composition of claim 1, wherein R_f has at least 8 carbon atoms.

4. The composition of claim 1, wherein the surfactant salt has a cation M⁺n selected from the group consisting of an alkali metal, an alkaline earth metal, a transition metal, a rare earth metal, a group IIB metal, a Group IIIB metal, tetraalkylammonium, N-alkylpyridinium and N,N′

-dialkylimidazolium.

5. The composition of claim 4, wherein the cation is selected from the group consisting of Li⁺, Na⁺, Ca⁺², Ba⁺², Al⁺³, Eu⁺³, Sm⁺³, (C₂H₅)₄N⁺, (CH₃)₄N⁺,

6. The composition of claim 1, wherein the surfactant salt is a member selected from the group consisting of (C₈F₁₇SO₂)N⁻

(SO₂CF₃) Li⁺, (C₄F₉SO₂)₂N⁻

Li⁺, (C₈F₁₇SO₂)₂N⁻

Li⁺, (C₈F₁₇SO₂)N⁻

, (SO₂C₄F₉) Li⁺, and ((CF₃)₂NCF₂CF₂SO₂)₂N⁻

Li⁺.

7. The composition of claim 1, wherein the molar ratio of conductive salt to surfactant salt is between about 99:

1 and about 90;

10.

8. The composition of claim 1, wherein the conductive salt has a (CF₃SO₂)₃C⁻

anion, or has an anion of the formula;

or has an anion of the formula;

 

R_f^VSO₃⁻

in which R_f1 and R_f2 are each independently a straight or branched perfluoroalkyl group of 1 to 4 carbon atoms, with R_f1 and R_f2 having a total of up to 5 carbon atoms;

R_f3 is a perfluoroalkylene moiety of 2 to 4 carbon atoms optionally substituted by a straight or branched perfluoroalkyl group of 1 to 2 carbon atoms, with R_f3 having a total of up to 4 carbon atoms; and

R_f^V is a perfluoroalkyl group having from 2 to 4 carbon atoms.

9. The composition of claim 1, wherein the conductive salt is a member selected from the group consisting of lithium bis(perfluoromethanesulfonyl)imide, lithium perfluoroethanesulfonate, lithium tris(perfluoromethanesulfonyl)methide, lithium bis(perfluoroethanesulfonyl)imide, lithium(perfluorobutanesulfonyl)(per-fluoromethanesulfonyl)imide, lithium perfluorobutane sulfonate, and a mixture thereof.

10. The composition of claim 1, wherein the conductive salt has an anion of the formula:

in which R_f1 and R_f2 are each independently a straight or branched perfluoroalkyl group of 1 to 4 carbon atoms, with R_f1 and R_f2 having a total of up to 5 carbon atoms;

R_f3 is a perfluoroalkylene moiety of 2 to 4 carbon atoms optionally substituted by a straight or branched perfluoroalkyl group of 1 to 2 carbon atoms, with R_f3 having a total of up to 4 carbon atoms.

11. The composition of claim 1, wherein the conductive salt is lithium bis(perfluoroethanesulfonyl)imide.

12. An electrochemical system comprising:

at least one positive electrode;

at least one negative electrode; and

an electrolyte composition comprising;

(a) a conductive salt comprising;

a cation selected from the group consisting of an alkali metal;

an alkaline earth metal;

a Group IIB metal;

a Group IIIB metal;

a transition metal;

a rare earth metal;

a nitrogen onium cation, and a proton; and

an anion selected from the group consisting of R_f⁰SO₃⁻

;

in which R_f⁰ is a perfluoroalkyl group having between 2 and 4 carbon atoms;

an anion of the formula;

in which R_f1 and R_f2 are each independently a straight or branched perfluoroalkyl group of 1 to 4 carbon atoms, with R_f1 and R_f2 having a total of 5 carbon atoms;

and R_f3 is a perfluoroalkylene moiety of 2 to 4 carbon atoms optionally substituted by a straight or branched perfluoroalkyl group of 1 to 2 carbon atoms, with R_f3 having a total of up to 4 carbon atoms;

an anion having a formula R_f4R_f5N—

(CH₂)_n′

SO₂—

X;

in which X⁻

is —

O⁻

, —

N⁻

SO₂R_f4′

or

Z is —

CF₂—

, —

O—

,

or —

SF₄—

;

R_f4, R_f4′

and R_f5, independently, are —

C_mF_2m+1, or —

(CF₂)_q—

SO₂—

X⁻

;

R_f6 and R_f7, independently, are —

C_mF_2m+1′

—

(CF₂)₄—

SO₂—

X⁻

;

R_f8 is —

C_mF_2m+1, or —

(CF₂)_q—

SO₂—

X⁻

;

R_f6′

, and R_f7′

, independently, are perfluoroalkylene moieties having the formula —

C_rF_2r—

;

n′

is 1-4;

r is 1-4;

m is 1-4; and

q is 1-4;

a bis-fluoroalkylsulfonyl methide anion R_f^II—

SO₂—

C⁻

(R)—

SO₂—

R_f^III in which R_f^II and R_f^III, independently, are perfluoroalkyl groups having between 1 and 4 carbon atoms, wherein the sum of R_f^II and R_f^III is up to 5 carbon atoms, and R is H, CN, F, alkyl of 1 to 6 carbon atoms, phenyl or phenyl substituted by alkyl of 1 to 4 carbon atoms;

and a tris-(perfluoroalkanesulfonyl)methide anion of the formula ⁻

C(SO₂R_f^II)(SO₂R_f^III)(SO₂R_f^IV) in which R_f^II, R_f^III, and R_f^IV, independently, are perfluoroalkyl groups having between 1 and 4 carbon atoms, wherein the sum of R_f^II, R_f^III and R_f^IV are up to 6 carbon atoms; and

(b) a surfactant salt of the formula;

13. The system of claim 12, which further comprises a non-aqueous matrix material.

14. The system of claim 12, wherein the molar ratio of conductive salt to surfactant salt is between about 99:

1 and about 90;

10.

15. The system of claim 12, wherein the surfactant salt has a cation M⁺ⁿ selected from the group consisting of an alkali metal, an alkaline earth metal, a transition metal, a rare earth metal, a group IIB metal, a Group IIIB metal, tetraalkylammonium, trialkylammonium, N-alkylpyridinium, N,N′

-dialkylimidazolium, and a proton.

16. The system of claim 15, wherein the cation is selected from the group consisting of Li⁺, Na⁺, Ca⁺², Ba⁺², Al⁺³, Eu⁺³, Sm⁺³, (C₂H₅)₄N⁺,(CH₃)₄N⁺,

17. The system of claim 12, wherein the surfactant salt is a member selected from the group consisting of (C₈F₁₇SO₂)N⁻

(SO₂CF₃)Li⁺, (C₄F₉SO₂)₂N⁻

Li⁺, (C₈F₁₇SO₂)N<sup>−

(SO</sup>₂C₄F₉)Li⁺, (C₈F₁₇SO₂)₂N⁻

Li⁺, and ((CF₃)₂NCF₂CF₂SO₂)₂N⁻

Li⁺.

18. The system of claim 12, wherein the electrolyte composition comprises:

(a) a conductive salt at a concentration from about 0.5 to 1.5 mole per liter; and

(b) a surfactant salt at a concentration from about 10 to 100 millimole per liter.

19. The system of claim 12, wherein the conductive salt has a (CF₃SO₂)₃C⁻

anion, or has an anion of the formula;

or has an anion of the formula;

20. The system of claim 12, wherein the conductive salt is lithium bis(perfluoroethanesulfonyl)imide.

21. The system of claim 12, being a battery or rechargeable battery.

22. The battery or rechargeable battery of claim 21, comprising a lithium-intercalated carbon anode and a metal oxide cathode.

23. A method of improving safety and performance of an electrochemical system which comprises using an electrolyte composition in said system comprising:

(a) an effective amount of a surfactant salt of the formula

24. The method of claim 23, wherein the system is a battery or rechargeable battery.

25. The method of claim 23, wherein the system is a lithium battery.

26. The method of claim 23, wherein the electrolyte composition comprises 10% by weight or more of the surfactant salt based on the weight of the conductive salt.

27. An electrochemical system comprising:

at least one positive electrode;

at least one negative electrode; and

an electrolyte composition comprising in a non-aqueous matrix material;

(a) a conductive salt having a cation selected from the group consisting of an alkali metal;

an alkaline earth metal;

a Group IIB metal;

a Group IIIB metal;

a transition metal;

a rare earth metal;

a nitrogen onium cation; and

a proton; and

an anion of the formula

in which R_f1 and R_f2 are each independently a straight or branched perfluoroalkyl group of 1 to 4 carbon atoms, with R_f1 and R_f2 having a total of up to 5 carbon atoms;

R_f3 is a perfluoroalkylene moiety of 2 to 4 carbon atoms optionally substituted by a straight or branched perfluoroalkyl group of 1 to 2 carbon atoms, with R_f3 having a total of up to 4 carbon atoms; and

(b) an effective amount of a surfactant salt of the formula

28. The system of claim 27, wherein the electrolyte composition comprises 10% by weight or more of the surfactant salt based on the weight of the conductive salt.

29. The system of claim 27, wherein the surfactant salt is a member selected from the group consisting of (C₈F₁₇SO₂)N⁻

(SO₂CF₃)Li⁺, (C₄F₉SO₂)₂N⁻

Li⁺, (C₈F₁₇SO₂)N⁻

(SO₂C₄F₉)Li⁺, (C₈F₁₇SO₂)₂N⁻

Li⁺, and ((CF₃)₂NCF₂CF₂SO₂)₂N⁻

Li⁺.

30. The system of claim 27, wherein the conductive salt has a lithium cation.

31. The system of claim 27, wherein the conductive salt is lithium bis(perfluoroethanesulfonyl)imide.

32. The system of claim 27, being a battery or rechargeable battery.

33. The battery or rechargeable battery of claim 32, comprising a lithium-intercalated carbon anode and a metal oxide cathode.

34. An electrolyte composition comprising in a matrix material:

(a) a conductive salt having a cation selected from the group consisting of an alkali metal;

an alkaline earth metal;

a Group IIB metal;

a Group IIIB metal;

a transition metal;

a rare earth metal;

a nitrogen onium cation; and

a proton; and

an anion of the formula;

in which R_f1 and R_f2 are each independently a straight or branched perfluoroalkyl group of 1 to 4 carbon atoms, with R_f1 and R_f2 having a total of up to 5 carbon atoms;

R_f3 is a perfluoroalkylene moiety of 2 to 4 carbon atoms optionally substituted by a straight or branched perfluoroalkyl group of 1 to 2 carbon atoms, with R_f3 having a total of up to 4 carbon atoms; and

(b) a surfactant salt of the formula ((R_fSO₂)(R_f′

SO₂)N⁻

)_nM⁺ⁿ

wherein M⁺ⁿ is a cation with a valence equal to n;

n is from 1 to 4;

R_f is a straight or branched perfluoroalkyl group of 1 to 12 carbon atoms, a perfluorocycloalkyl group or a perfluorocycloalkyl perfluoroalkyl group of 4-7 ring carbon atoms and 1-4 carbon atoms in the alkyl chain, which perfluoroalkyl or perfluorocycloalkyl chain may optionally contain catenary heteroatoms; and

R_f′

is a straight or branched perfluoroalkyl group of 1 to 12 carbon atoms, a perfluorocycloalkyl group or a perfluorocycloalkyl perfluoroalkyl group of 4-7 ring carbon atoms and 1-4 carbon atoms in the alkyl chain, which perfluoroalkyl or perfluorocycloalkyl chain may optionally contain catenary heteroatoms, wherein R_f and R_f′

have a total of at least 8 carbon atoms.

35. The composition of claim 34, wherein the conductive salt has a lithium cation.

36. The composition of claim 34, wherein the conductive salt is lithium bis(perfluoroethanesulfonyl)imide.

37. The composition of claim 34, wherein R_f has at least 8 carbon atoms.

38. The composition of claim 34, wherein the surfactant salt has a cation M⁺ⁿ selected from the group consisting of an alkali metal, an alkaline earth metal, a transition metal, a rare earth metal, a group IIB metal, a Group IIIB metal, tetraalkylammonium, N-alkylpyridinium and N,N′

-dialkylimidazolium.

39. The composition of claim 34, wherein the surfactant salt has a lithium cation.

40. The composition of claim 34, wherein the surfactant salt is a member selected from the group consisting of (C8F₁₇SO₂)N⁻

(SO₂CF₃)Li⁺, (C₄F₉SO₂)₂N⁻

Li⁺, (C₈F₁₇SO₂)N⁻

(SO₂C₄F₉)Li⁺, (C₈F₁₇SO₂)₂N⁻

Li⁺, and ((CF₃)₂NCF₂CF₂SO₂)₂N⁻

Li⁺.

41. The composition of claim 34, wherein the surfactant salt comprises 10% by weight or more of the composition based on the weight of the conductive salt.