Electrolytes for lithium-ion batteries

1. An electrochemical device comprising:

a cathode having a voltage of greater than 4.2 V v. Li/Li + ;

an anode comprising lithium metal and one or more of natural graphite, synthetic graphite, hard carbon, amorphous carbon, soft carbon, mesocarbon microbeads, acetylene black, Ketjen black, carbon black, mesoporous carbon, porous carbon matrix, carbon nanotube, carbon nanofiber, graphene, and a silicon-carbon composite;

a separator; and

an electrolyte comprising:

a salt;

a fluorinated sulfone represented by Formula (I); and

a fluorinated carbonate;

wherein:

the electrolyte is substantially free of non-fluorinated carbonates;

the fluorinated sulfone represented by Formula (I) is:

R 1 is alkyl or fluorinated alkyl;

R 2 is H, alkyl, fluorinated alkyl, aryl, or aralkyl; and

n is 1, 2, or 3.

2. The electrochemical device of claim 1 , wherein R 1 is —CH 3 , —CH 2 CH 3 , —CH 2 CH 2 CH 3 , —H(CH 3 ) 2 , —CFH 2 , —CF 2 H, —CF 3 , —CF 2 CF 3 , —CF 2 CHF 2 , —CF 2 CH 3 , —CF 2 CH 2 F, —CHFCF 3 , —CHFCHF 2 , —CHFCH 3 , —CHFCH 2 F, —CH 2 CF 3 , —CH 2 CHF 2 , —CH 2 CH 2 F, —CF(CF 3 ) 2 , —CH(CF 3 ) 2 , —CF 2 CF 2 CF 3 , —CF 2 CF 2 CHF 2 , —CF 2 CF 2 CH 3 , —CF 2 CF 2 CH 2 F, —CH 2 CF 2 CF 3 , —CH 2 CF 2 CHF 2 , —CH 2 CF 2 CH 3 , —CH 2 CF 2 CH 2 F, —CHFCF 2 CF 3 , —CHFCF 2 CHF 2 , —CHFCF 2 CH 3 , —CHFCF 2 CH 2 F, —CF 2 CH 2 CF 3 , —CF 2 CH 2 CHF 2 , —CF 2 CH 2 CH 3 , —CF 2 CH 2 CH 2 F, —CF 2 CHFCF 3 , —CF 2 CHFCHF 2 , —CF 2 CHFCH 3 , —CF 2 CHFCH 2 F, —CHFCHFCF 3 , —CHFCHFCHF 2 , —CHFCHFCH 3 , —CHFCHFCH 2 F, —CH 2 CH 2 CF 3 , —CH 2 CH 2 CHF 2 , or —CH 2 CH 2 CH 2 F; R 2 is H; and n is 1.

3. The electrochemical device of claim 2 , wherein R 1 is —CH 3 ; R 2 is H; and n is 1.

4. The electrochemical device of claim 3 , wherein the salt consists of Li[N(FSO 2 ) 2 ].

5. The electrochemical device of claim 1 , wherein the salt comprises Li[CF 3 CO 2 ]; Li[C 2 F 5 CO 2 ]; Li[ClO 4 ]; Li[BF 4 ]; Li[AsF 6 ]; Li[PF 2 (C 2 O 4 ) 2 ]; Li[PF 4 C 2 O 4 ]; Li[CF 3 SO 3 ]; Li[N(FSO 2 ) 2 ]; Li[N(CF 3 SO 2 ) 2 ]; Li[C(CF 3 SO 2 ) 3 ]; Li[N(SO 2 C 2 F 5 ) 2 ]; lithium alkyl fluorophosphates; Li[B(C 2 O 4 ) 2 ]; Li[BF 2 C 2 O 4 ]; Li 2 [B 12 X 12−k H k ]; or Li 2 [B 10 X 10−k′ ]; wherein X is OH, F, Cl, or Br; k is an integer from 0 to 12; and k′ is an integer from 0 to 10.

6. The electrochemical device of claim 1 , wherein the salt comprises Li[PF 6 ] or Li[N(CF 3 SO 2 ) 2 ], Li[N(FSO 2 ) 2 ], or a mixture thereof.

7. The electrochemical device of claim 1 , wherein the salt comprises Li[N(FSO 2 ) 2 ].

8. The electrochemical device of claim 1 , wherein the salt consists of Li[PF 6 ] or Li[N(FSO 2 ) 2 ] or a mixture thereof.

9. The electrochemical device of claim 1 , wherein the salt consists of Li[N(FSO 2 ) 2 ].

10. The electrochemical device of claim 1 , wherein the fluorinated carbonate comprises:

or a mixture thereof.

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

12. The electrochemical device of claim 1 that is a lithium secondary battery.

13. The electrochemical device of claim 1 , wherein the cathode comprises a spinel, an olivine, a carbon-coated olivine 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 provisos that at least one of h, k and 1 is greater than 0, and at least one of x, y and z is greater than 0.

14. The electrochemical device of claim 1 , wherein the cathode comprises LiMn 0.5 Ni 0.5 O 2 , LiCoO 2 , LiNiO 2 , LiNi 1−x Co y Mn z O 2 , or a combination of any two or more thereof, wherein 0≤x≤0.3; 0≤y≤0.5; 0≤z≤0.5.

15. The electrochemical device of claim 1 , wherein:

the cathode comprises LiNi 0.33 Co 0.33 Mn 0.33 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , or LiNi 0.8 Co 0.1 Mn 0.1 O 2 ;

the salt comprises lithium bis(fluorosulfonyl)imide; and

and the fluorinated sulfone is 1,1,2,2-tetrafluoro-3-(methylsulfonyl)propane.

16. An electrochemical device comprising:

a cathode having a voltage of greater than 4.2 V v. Li/Li + ;

an anode comprising lithium metal and one or more of natural graphite, synthetic graphite, hard carbon, amorphous carbon, soft carbon, mesocarbon microbeads, acetylene black, Ketjen black, carbon black, mesoporous carbon, porous carbon matrix, carbon nanotube, carbon nanofiber, graphene, and a silicon-carbon composite;

a separator; and

an electrolyte comprising:

lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, or a mixture thereof;

a fluorinated sulfone; and

a fluorinated carbonate;

wherein the electrolyte is substantially free of non-fluorinated carbonates.

17. The electrochemical cell of claim 16 , wherein the fluorinated sulfone is represented by Formula (I):

R 1 is alkyl or fluorinated alkyl;

R 2 is H, alkyl, fluorinated alkyl, aryl, or aralkyl; and

n is 1, 2, or 3.