Electrolytes for lithium batteries
A lithium ion battery includes a cathode including a cathode active material; an anode including silicon, a conductive carbon, lithium metal, or a combination of any two or more thereof; a separator; and an electrolyte including a lithium sulfonylimide salt, a dicarbonyl solvent, and a fluorinated ether solvent.
1 . An electrochemical cell comprising:
a cathode comprising a cathode active material;
an anode comprising lithium metal;
a separator; and
an electrolyte comprising LiN(SO 2 F) 2 , a dicarbonyl solvent, and a fluorinated ether solvent, wherein the dicarbonyl solvent and the fluorinated ether solvent are presented in a volume ratio from 4:1 to 1:4 and
wherein the dicarbonyl solvent is dimethyldicarbonate; diethyl dicarbonate; acetylacetone; ethyl acetoacetate; di-tert-butyl dicarbonate; 3,3-dimethyl-2,4-pentanedione; 2,2,6,6-tetramethyl-3,5-heptanedione; or 1,1,1-trifluoro-2,4-pentanedione.
2 . The electrochemical cell of claim 1 , wherein the fluorinated ether is a compound represented as Formula I or II:
wherein:
in Formula (I):
R 1 and R 2 may be individually alkyl, R 20 O-alkyl-, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroarylalkyl, heterocyclylalkyl, heterocyclylalkyl, cycloalkyl, cycloalkylalkyl; and
R 20 is H, alkyl, cycloalkyl, cycloalkylalkyl, alkenyl, alkynyl, aryl, aralkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, heteroarylalkyl, or siloxy;
or where R 1 and R 2 may join together to form a cyclic compound incorporating an —O—S(O) 2 —O— group; and
with the proviso that at least one R 1 and R 2 is fluorinated; and
in Formula (II):
R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 may individually be H, alkyl, R 20 O-alkyl-, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroarylalkyl, heterocyclylalkyl, heterocyclylalkyl, cycloalkyl, cycloalkylalkyl, or silyl; and
R 20 is H, alkyl, cycloalkyl, cycloalkylalkyl, alkenyl, alkynyl, aryl, aralkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, heteroarylalkyl, or siloxy;
or where two of R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 may join together to form a cyclic compound incorporating an —O—S(O) 2 —O— group;
with the proviso that at least one R 3 and R 8 is fluorinated.
3 . The electrochemical cell of claim 2 , wherein the fluorinated ether is a compound represented as Formula I or II:
R 1 and R 2 are non-fluorinated alkyl or fluorinated alkyl;
R 3 and R 8 are non-fluorinated alkyl or fluorinated alkyl;
R 4 , R 5 , R 6 , and R 7 are individually H, nonfluorinated alkyl, or fluorinated alkyl; and
x is 0, 1, 2, 3, or 4;
with the provisos that at least one of R 1 or R 2 is fluorinated alkyl; and at least one of R 3 and R 8 is fluorinated alkyl.
4 . The electrochemical cell of claim 2 , wherein R 1 , R 2 , R 3 , and R 8 are individually —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 ; —CH 2 CH 2 CH 2 F; —CF 2 CF 2 CF 2 CF 3 ; —CF 2 CF 2 CF 2 CH 3 ; —CF 2 CF 2 CF 2 CHF 2 ; —CF 2 CF 2 CF 2 CH 2 F; —CH 2 CF 2 CF 2 CF 3 ; —CH 2 CF 2 CF 2 CH 3 ; —CH 2 CF 2 CF 2 CHF 2 ; —CH 2 CF 2 CF 2 CH 2 F; —CHFCF 2 CF 2 CF 3 ; —CHFCF 2 CF 2 CH 3 ; —CHFCF 2 CF 2 CHF 2 ; —CHFCF 2 CF 2 CH 2 F; —CF 2 CH 2 CF 2 CF 3 ; —CF 2 CH 2 CF 2 CH 3 ; —CF 2 CH 2 CF 2 CHF 2 ; —CF 2 CH 2 CF 2 CH 2 F; —CF 2 CHFCF 2 CF 3 ; —CF 2 CHFCF 2 CH 3 ; —CF 2 CHFCF 2 CHF 2 ; —CF 2 CHFCF 2 CH 2 F; —CHFCHFCF 2 CF 3 ; —CHFCHFCF 2 CH 3 ; —CHFCHFCF 2 CHF 2 ; —CHFCHFCF 2 CH 2 F; —CH 2 CH 2 CF 2 CF 3 ; —CH 2 CH 2 CF 2 CH 3 ; —CH 2 CH 2 CF 2 CHF 2 ; —CH 2 CH 2 CF 2 CH 2 F; —CF 2 CF 2 CF 2 CF 2 CF 3 ; —CH 2 CF 2 CF 2 CF 2 CF 3 ; —CF 2 CF 2 CF 2 CF 2 CHF 2 ; —CH 2 CF 2 CF 2 CF 2 CHF 2 ; —CF 2 OCFH 2 ; —CF 2 OCF 2 H; —CF 2 OCF 3 ; —CF 2 OCF 2 CF 3 ; —CF 2 OCF 2 CHF 2 ; —CF 2 OCF 2 CH 3 ; —CF 2 OCF 2 CH 2 F; —CF 2 OCHFCF 3 ; —CF 2 OCHFCHF 2 ; —CF 2 OCHFCH 3 ; —CF 2 OCHFCH 2 F; —CF 2 OCH 2 CF 3 ; —CF 2 OCH 2 CHF 2 ; —CF 2 OCH 2 CH 2 F; —CH 2 OCFH 2 ; —CH 2 OCF 2 H; —CH 2 OCF 3 ; —CH 2 OCF 2 CF 3 ; —CH 2 OCF 2 CHF 2 ; —CH 2 OCF 2 CH 3 ; —CH 2 OCF 2 CH 2 F; —CH 2 OCHFCF 3 ; —CH 2 OCHFCHF 2 ; —CH 2 OCHFCH 3 ; —CH 2 OCHFCH 2 F; —CH 2 OCH 2 CF 3 ; —CH 2 OCH 2 CHF 2 ; —CH 2 OCH 2 CH 2 F; —CHFOCFH 2 ; —CHFOCF 2 H; —CHFOCF 3 ; —CHFOCF 2 CF 3 ; —CHFOCF 2 CHF 2 ; —CHFOCF 2 CH 3 ; —CHFOCF 2 CH 2 F; —CHFOCHFCF 3 ; —CHFOCHFCHF 2 ; —CHFOCHFCH 3 ; —CHFOCHFCH 2 F; —CHFOCH 2 CF 3 ; —CHFOCH 2 CHF 2 ; or —CHFOCH 2 CH 2 F.
5 . The electrochemical cell of claim 2 , wherein R 3 , R 4 , R 5 , and R 6 are individually H, C 1 -C 8 -nonfluorinated alkyl, or C 1 -C 8 fluoroalkyl.
6 . The electrochemical cell of claim 1 , wherein the fluorinated ether is 1,1,2,2-tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)propane; 2,2,3,3-tetrafluoro-1,4-dimethoxybutane; bis(2,2,2-trifluoroethyl) ether; 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; 1,1,2,3,3,3-hexafluoropropyl 2,2,2-trifluoroethyl ether; 1,1,2,2-tetrafluoroethyl-1H,1H,5H-octafluoropentyl ether; 1,2-(1,1,2,2-tetrafluoroethoxy)ethane; 1,3-(1,1,2,2-tetrafluoroethoxy)propane, or a mixture of any two or more thereof.
7 . The electrochemical cell of claim 2 , wherein the dicarbonyl compound is dimethyldicarbonate; diethyl dicarbonate; or di-tert-butyl dicarbonate.
8 . The electrochemical cell of claim 1 further comprising an electrolyte stabilizing additive comprising 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 ), 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.
9 . The electrochemical cell of claim 1 , wherein the electrolyte further comprises an aprotic gel polymer.
10 . The electrochemical cell of claim 1 which is a lithium secondary battery.
11 . The electrochemical cell of claim 10 , wherein the secondary battery is a lithium battery or a lithium-air battery.
12 . 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 l 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 l is greater than 0.
13 . The electrochemical cell of claim 1 , wherein the dicarbonyl solvent comprises dimethyl dicarbonate, the fluorinated ether solvent comprises F 2 HCCF 2 OCH 2 CF 2 CHF 2 , and the dicarbonyl solvent and the fluorinated ether solvent are present at about 2:1 volume ratio and wherein the LiN(SO 2 F) 2 is present in the electrolyte at a molar ratio of about 4:5 with the dicarbonyl solvent.
14 . The electrochemical cell of claim 1 , wherein the dicarbonyl solvent is dimethyldicarbonate or diethyl dicarbonate and the fluorinated ether is 1,1,2,2-tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)propane.