Electrolytes for lithium batteries

1. An electrochemical cell comprising:

a cathode comprising a cathode active material;

an anode comprising silicon, a graphite, lithium metal, or a combination of any two or more thereof;

a separator; and

an electrolyte comprising a lithium salt and a fluorinated glycol ether and a fluorinated cyclic carbonate;

wherein:

the fluorinated glycol ether is a compound represented as Formula I:

R 1 (O(CH 2 ) m ) x (O(CH 2 ) n ) y OR 2 (I);

R 1 is fluorinated alkyl;

R 2 is fluorinated alkyl;

m is 1, 2, 3, or 4;

n is 0, 1, 2, 3, or 4;

x is 2 to 10; and

y is 0.

2. The electrochemical cell of claim 1 , wherein R 1 and R 2 are at least difluorinated alkyl.

3. The electrochemical cell of claim 1 , wherein R 1 and R 2 are at least trifluorinated alkyl.

4. The electrochemical cell of claim 1 , wherein R 1 and R 2 are individually−(CH 2 ) q (CR 4 R 5 ) p C(R 3 ) 3 ; each R 3 , R 4 , and R 5 is individually H or F, with the proviso that at least one of R 3 , R 4 , and R 5 is F; q is 0, 1, 2, or 3; and p is 0, 1, 2, 3, 4, 5, or 6.

5. The electrochemical cell of claim 1 , wherein R 1 and R 2 are individually−(CH 2 ) q (CR 4 R 5 ) p C(R 3 ) 3 ; R 3 is F; q is 1 or 2; and p is 0.

6. The electrochemical cell of claim 1 , wherein R 1 and R 2 are individually−(CH 2 ) q (CR 4 R 5 ) p C(R 3 ) 3 ; each R 3 , R 4 , and R 5 is individually H or F, with the proviso that at least one of R 3 , R 4 , and R 5 is F; y is 0; x is 2, 3, 4, 5, or 6; m is 1, 2, or 3; q is 0, 1, 2, or 3; and p is 0, 1, 2, 3, 4, 5, or 6.

7. The electrochemical cell of claim 1 , wherein R 1 and R 2 are individually−(CH 2 ) q (CR 4 R 5 ) p C(R 3 ) 3 ; R 3 is F; y is 0; x is 2, 3, or 4; m is 1, 2, or 3; q is 1 or 2; and p is 0.

8. The electrochemical cell of claim 1 , wherein R 1 and R 2 are individually−(CH 2 ) q (CR 4 R 5 ) p C(R 3 ) 3 ; q is 1; p is 0; R 3 is F; y is 0; x is 2 or 3; and m is 2.

9. The electrochemical cell of claim 1 , wherein the fluorinated cyclic carbonate is a compound represented as Formula (II):

wherein:

each of R 10 , R 11 , R 12 , and R 13 is individually, H, F, Cl, Br, I, CN, NO 2 , alkyl, alkenyl, aryl, aralkyl, heterocyclyl, heteroaryl, or heteroaralkyl, with the proviso that at least one of R 10 , R 11 , R 12 , and R 13 is F or contains F.

10. The electrochemical cell of claim 9 , wherein each of R 10 , R 11 , R 12 , and R 13 is individually, H, F, C 1 -C 8 alkyl, or C 1 -C 8 fluoroalkyl.

11. The electrochemical cell of claim 10 , wherein each of R 10 , R 11 , and R 12 are H and R 13 is F; or wherein each of R 10 and R 11 are H, and R 12 and R 13 are F; or wherein each of R 11 and R 12 are H, and R 10 and R 13 are F; or wherein any 3 of R 10 , R 11 , R 12 and R 13 are F while the remaining one is H; or wherein each of R 10 , R 11 , R 12 , and R 13 are F.

12. The electrochemical cell of claim 1 , wherein fluorinated cyclic

carbonate is,

or a mixture of any two or more thereof.

13. The electrochemical cell of claim 1 further comprising an electrolyte stabilizing additive that is LiBF 2 (C 2 O 4 ), LiB(C 2 O 4 ) 2 , LiPF 2 (C 2 O 4 ) 2 , LiPF 4 (C 2 O 4 ), LiPF 6 , LiAsF 6 , CsF, CsPF 6 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 F) 2 , Li 2 (B 12 X 12-i H i ); Li 2 (B 10 X 10-i′ H i′ ); or a mixture of any two or more thereof;

wherein X is independently at each occurrence a halogen, i is an integer from 0 to 12 and i′ is an integer from 0 to 10.

14. The electrochemical cell of claim 1 , wherein the lithium salt is LiBF 2 (C 2 O 4 ); LiB(C 2 O 4 ) 2 ; LiPF 2 (C 2 O 4 ) 2 ; LiPF 4 (C 2 O 4 ); LiPF 6 ; lithium 4,5-dicyano-2-(trifluoromethyl)imidazole; lithium 4,5-dicyano-2-methylimidazole; trilithium 2,2′,2″-tris(trifluoromethyl)benzotris(imidazolate); LiN(CN) 2 ; Li(CF 3 CO 2 ); Li(C 2 F 5 CO 2 ); LiCF 3 SO 3 ; LiCH 3 SO 3 ; LiN(SO 2 CF 3 ) 2 ; LiN(SO 2 F) 2 ; LiC(CF 3 SO 2 ) 3 ; LiN(SO 2 C 2 F 5 ) 2 ; LiClO 4 ; LiBF 4 ; LiAsF 6 ; LiPF 6 ; LiPF 2 (C 2 O 4 ) 2 ; LiPF 4 (C 2 O 4 ); LiB(C 2 O 4 ) 2 ; LiBF 2 (C 2 O 4 ) 2 ; Li 2 (B 12 X 12-i H i ); Li 2 (B 10 X 10-i′ H i′ ); and a mixture of any two or more thereof, wherein X is independently at each occurrence a halogen, i is an integer from 0 to 12 and i′ is an integer from 0 to 10.

15. The electrochemical cell of claim 1 , wherein the electrolyte further comprises an aprotic gel polymer.

16. The electrochemical cell of claim 1 which is a lithium secondary battery.

17. The electrochemical cell of claim 16 , wherein the secondary battery is a lithium battery or a lithium-air battery.

18. The electrochemical cell of claim 1 , wherein the cathode active material comprises a spinel, an olivine, a carbon-coated olivine LiFePO 4 , LiMn 0.5 Ni 0.5 O 2 , LiCoO 2 , LiNiO 2 , LiNi 1-x Co y Me z O 2 , LiNi α Mn β Co γ O 2 , LiMn 2 O 4 , LiFeO 2 , LiNi 0.5 Me 1.5 O 4 , Li 1=x Ni h Mn k Co 1 Me 2 y′ O 2-z′ F z′ , VO 2 or E x″ F 2 (Me 3 O 4 ) 3 , LiNi m Mn n O 4 , wherein Me is Al, Mg, Ti, B, Ga, Si, Mn, or Co; Me 2 is Mg, Zn, Al, Ga, B, Zr, or Ti; E is Li, Ag, Cu, Na, Mn, Fe, Co, Ni, or Zn; F is Ti, V, Cr, Fe, or Zr; wherein 0≤x≤0.3; 0≤y≤0.5; 0≤z≤0.5; 0≤m≤2; 0≤n≤2; 0≤x′≤0.4; 0≤α≤1; 0≤β≤1; 0≤γ≤1; 0≤h≤1; 0≤k≤1; 0≤l≤1; 0≤y′≤0.4; 0≤z′≤0.4; and 0≤x″≤3; with the proviso that at least one of h, k and 1 is greater than 0.

19. An electrochemical cell comprising:

a cathode comprising a cathode active material;

an anode comprising silicon, a graphite, lithium metal, or a combination of any two or more thereof;

a separator; and

an electrolyte comprising a lithium salt and a fluorinated glycol ether and a fluorinated cyclic carbonate;

wherein:

the fluorinated glycol ether is a compound represented as Formula I:

R 1 (O(CH 2 ) m ) x (O(CH 2 ) n ) y OR 2 (I);

R 1 and R 2 are individually−(CH 2 ) q CF 3 ;

q is 1 or 2;

m and n are individually 0, 1, 2, 3, or 4; and

x and y are 0 to 10, with the proviso that both x and y are not 0.